WO2020003569A1 - Electrical power tool, method for controlling same, and control program - Google Patents

Abstract

An electrical power tool (10) is provided with a motor (16), a trigger switch (12), a switching circuit (gate circuit (13) and FET array (14)), and a control unit (20). The trigger switch (12) sets the rotational speed of the motor (16) according to the amount of operation thereof. The gate circuit (13) and the FET array (14) have a plurality of switching elements (14a) and supply electrical power to the motor (16). The control unit (20) controls the gate circuit (13) and the FET array (14) so as to rotationally drive the motor (16) on the basis of the rotational speed set in the trigger switch (12) and, on the basis of a characteristic value that is related to the motor (16) and that is acquired in a first task, sets a control condition for the motor (16) in a second task that is scheduled to be performed following the first task and that is of the same type as the first task.

Description

Electric power tool, control method therefor, and control program

The present invention relates to a power tool, a control method thereof, and a control program.

Electric tools usually perform various operations such as screw tightening and drilling, using the motor control parameters set at the time of factory shipment as they are. For this reason, in drilling and text screw tightening, various processing members (hard materials such as metal and keyaki, soft materials such as gypsum and cedar, heterogeneous materials such as natural solid wood, gypsum board and laminated wood, etc.) However, there was a problem that only moderate workability could be obtained with respect to homogeneous materials.

For example, in Patent Document 1, a learning operation is performed in a predetermined sample mode to learn a use condition of a motor and store it as control information (for example, a tightening time by a motor, a current limit value, a rotation speed, and the like). A power tool that can realize an optimal drive mode for each user is disclosed.

JP 2013-022681 A

However, the above-described conventional power tool has the following problems.
That is, in the electric tool disclosed in the above publication, the motor is driven so as to be under the optimal driving condition at the time of actual work based on the control information obtained by performing the learning operation in the predetermined sample mode. .
However, in order to perform the learning operation, it is necessary to set a predetermined sample mode before performing the actual work, which is troublesome for the user.

An object of the present invention is to provide an electric power tool capable of setting optimum motor control conditions by a simple operation, a control method thereof, and a control program.
A power tool according to a first aspect includes a DC motor, a speed setting unit, a switching circuit, and a control unit. The speed setting unit sets the rotation speed of the DC motor according to the operation amount. The switching circuit has a plurality of switching elements and supplies power to the DC motor. The control unit controls the switching circuit so as to rotate the DC motor based on the rotation speed set by the speed setting unit, and performs the first operation based on the characteristic value regarding the DC motor acquired in the first operation. Then, the control condition of the DC motor in the second operation of the same type as the first operation is set.

Here, for example, when the same kind of work is continuously performed on the same kind of work material using an electric tool used in various kinds of work such as screw tightening and drilling, the DC power acquired in the first work is used. Based on the characteristic values related to the motor, the control condition of the DC motor in the second operation performed after the first operation is optimized.
That is, in the power tool of the present invention, when the same type of work is continuously performed on the same type of processing material, the characteristic values such as the rotation speed and the current value of the DC motor acquired at the time of the operation in the first operation are used. Then, the control condition for the second operation is set so that the second operation in which the same type of operation is performed next is performed under the optimum control condition.

Here, the same kind of work using the electric tool includes, for example, screw tightening, screw loosening, drilling, and the like. Examples of the same type of processing material include various materials such as metal, wood, resin, and rubber.
In addition, the first work and the second work are not limited to the first work and the second work in a series of the same kind of work that is continuously performed. For example, the fifth work and the sixth work are performed. It is sufficient that the work is merely in-context work, such as the second work.

The optimization of the control condition may be repeatedly performed for each operation, may be performed only between the first operation and the second operation of the series of operations, It may be carried out every time the predetermined number of times is reached.
Further, as the characteristic value related to the DC motor, for example, the operation amount of the speed setting unit that rotationally drives the DC motor, the target rotation speed of the DC motor corresponding to this, the actual rotation speed, the battery voltage, the current value flowing through the DC motor , DC motor temperature, and the like.

Accordingly, when the same type of work is continuously performed on the same type of processing material using the electric tool, the first type of operation is performed following the first type of operation based on the characteristic values of the DC motor acquired in the first operation. It is possible to optimize the control condition of the DC motor in the performed second operation.
Therefore, it is not necessary to change the setting to a special mode for the learning operation to optimize the control condition of the DC motor. Can be

A power tool according to a second invention is the power tool according to the first invention, and further includes a detection unit that detects an actual rotation speed of the DC motor. The characteristic value includes a difference between the target rotation speed of the DC motor with respect to the operation amount of the speed setting unit and the actual rotation speed detected by the detection unit.
Here, the difference between the target rotation speed of the DC motor with respect to the operation amount of the speed setting unit and the actual rotation speed detected by the detection unit is used as the characteristic value used in the optimization control of the control condition of the DC motor. .

Specifically, when the difference between the target rotation speed and the actual rotation speed of the DC motor acquired in the first operation is large, the control condition of the DC motor is adjusted to be large in order to reduce the difference. On the other hand, when the difference is small, the control condition of the DC motor is slightly adjusted to further reduce the difference.
Thereby, it is possible to optimize the control condition of the DC motor at the time of performing the second operation according to the magnitude of the difference between the target rotation speed and the actual rotation speed of the DC motor acquired in the first operation. it can.

A power tool according to a third invention is the power tool according to the second invention, wherein the control unit performs an operation of the speed setting unit according to a magnitude of the difference when performing the second work. The table indicating the relationship with the target rotation speed is rewritten.
Here, in the DC motor optimization control using the difference between the target rotation speed and the actual rotation speed of the DC motor acquired in the first operation described above, the operation of the speed setting unit is performed in accordance with the magnitude of the difference. The table showing the relationship between the amount and the target rotation speed is rewritten.

Specifically, when the difference between the target rotation speed of the DC motor and the actual rotation speed obtained in the first work is large, for example, in order to reduce the difference, for example, the operation amount of the speed setting unit and the target The inclination of the table indicating the relationship with the rotation speed is adjusted to be large. On the other hand, when the difference is small, for example, the inclination of the table is slightly adjusted to further reduce the difference.
Thereby, for example, according to the magnitude of the difference between the target rotation speed and the actual rotation speed of the DC motor acquired in the first operation, for example, a table of the relationship between the operation amount of the speed setting unit and the target rotation speed is displayed. By adjusting the inclination and the like, the second operation can be performed under optimal conditions.

An electric power tool according to a fourth aspect is the electric power tool according to the second or third aspect, wherein the control unit outputs to the switching circuit in accordance with the magnitude of the difference when performing the second operation. The control gain to be adjusted.
Here, in the DC motor optimization control using the difference between the target rotation speed and the actual rotation speed of the DC motor acquired in the first operation described above, the DC motor output is output to the switching circuit in accordance with the magnitude of the difference. Control gain (proportional gain, integral gain, derivative gain, etc. in speed feedback control).

Specifically, when the difference between the target rotation speed and the actual rotation speed of the DC motor acquired in the first operation is large, for example, a control gain output to a switching circuit is used to reduce the difference. Adjust to a large value. On the other hand, when the difference is small, for example, the control gain is slightly adjusted to further reduce the difference.
Thereby, the control gain output to the switching circuit is adjusted in accordance with the magnitude of the difference between the target rotation speed and the actual rotation speed of the DC motor acquired in the first operation, so that the optimum condition can be obtained. A second operation can be performed.
The adjustment by the control gain may be performed in combination with the above-described control for adjusting the inclination of the table indicating the relationship between the operation amount of the speed setting unit and the target rotation speed, or may be performed independently. .

A power tool according to a fifth invention is the power tool according to any one of the first to fourth inventions, further comprising a current measuring unit that measures a current flowing in a circuit connected to the DC motor. ing.

Here, a current flowing in a circuit connected to the DC motor is measured using a current measuring unit.
Thereby, in addition to the optimization control based on the difference between the target rotation speed and the actual rotation speed of the DC motor acquired in the first operation, the optimization control based on the current value such as the average current and the current ripple is performed. can do.

A power tool according to a sixth invention is the power tool according to the fifth invention, wherein the characteristic value is at least one of an average current and a current ripple calculated based on the current value measured by the current measurement unit. Is included.
Here, at least one of the average current and the current ripple calculated based on the current value measured by the current measurement unit is used as the characteristic value used in the optimization control of the control condition of the DC motor.
Thereby, the control condition of the DC motor when performing the second operation can be optimized according to at least one of the average current and the current ripple acquired in the first operation.

An electric power tool according to a seventh aspect is the electric power tool according to the sixth aspect, wherein the control section performs a second operation, wherein the speed setting section performs at least one of the average current and the current ripple. Rewrite the table indicating the target rotation speed of the DC motor corresponding to the operation amount.

Here, in the DC motor optimization control using at least one of the average current and the current ripple acquired in the above-described first operation, the operation amount of the speed setting unit according to the value of the average current and / or the current ripple. The table showing the relationship between the target rotation speed and the target rotation speed is rewritten.
Thereby, for example, the relationship between the operation amount of the speed setting unit and the target rotation speed is determined in accordance with the average current of the current flowing in the circuit connected to the DC motor and / or the value of the current ripple obtained in the first operation. The second operation can be performed under optimal conditions by adjusting the inclination of the table shown.

The power tool according to an eighth invention is the power tool according to the sixth or seventh invention, wherein the control unit performs at least one of the average current and the current ripple when performing the second operation. Adjust the control gain output to the switching circuit.
Here, in the optimization control of the DC motor using at least one of the average current and the current ripple acquired in the first operation described above, the DC current is output to the switching circuit according to the value of the average current and / or the current ripple. Adjust the control gain.

Thereby, for example, by adjusting the control gain output to the switching circuit according to the average current and / or the current ripple value of the current flowing in the circuit connected to the DC motor acquired in the first operation, The second operation can be performed under optimal conditions.
The adjustment by the control gain may be performed in combination with the above-described control for adjusting the inclination of the table indicating the relationship between the operation amount of the speed setting unit and the target rotation speed, or may be performed independently. .

A power tool according to a ninth aspect is the power tool according to any one of the first to eighth aspects, wherein the control unit is configured to perform the control based on the characteristic value of the DC motor acquired in the first operation. Estimate the quality of the processing material.
Here, from the characteristic values of the DC data acquired in the first operation, the material of the processing material to be screwed, loosened, drilled, or the like is estimated.

Specifically, for example, when the difference between the actual rotation speed detected by the detection unit and the target rotation speed of the DC motor with respect to the operation amount of the speed setting unit described above is large on the minus side, the processing material is a hard material. It is presumed that there is. Conversely, when the difference is large on the positive side, it is estimated that the processed material is a soft material.
Thus, by estimating the material of the processing material using one or more of the characteristic value such as the difference between the actual rotation speed with respect to the target rotation speed, the average current of the DC motor, and the current ripple, the second work can be performed. , More optimal control conditions can be set.

A power tool according to a tenth aspect is the power tool according to the ninth aspect, wherein the material of the processing material includes hardness and homogeneity.
Here, the hardness and homogeneity of the material are listed as the material of the estimated processing material.
With this, when performing the same kind of work continuously, it is necessary to set the optimal control condition of the DC motor at the time of the second work in consideration of the hardness and homogeneity of the material to be worked on. Can be.

An electric power tool according to an eleventh aspect is the electric power tool according to any one of the first to tenth aspects, further comprising a storage unit that stores a characteristic value of the DC motor.
Here, the characteristic values used for the above-described DC motor optimization control are stored in the storage unit.
With this, the difference between the target rotation speed of the DC motor with respect to the operation amount of the speed setting unit and the actual rotation speed of the DC motor, the average current, the current ripple, and other various characteristic values stored in the storage unit are used. Optimization control of the DC motor during the two operations can be performed.

A power tool according to a twelfth aspect is the power tool according to any one of the first to eleventh aspects, further comprising a reset switch for returning a control condition of the DC motor to an initial condition.
Here, when a series of similar operations performed continuously is completed and another type of operation is started, a reset switch is operated to reset the control conditions of the DC motor to the initial conditions.
As a result, when transitioning from the same type of work performed successively to another work, the optimized control conditions of the previous work are deleted, the initial conditions are restored, and then the optimization control is performed again. Can be implemented.

A power tool according to a thirteenth aspect is the power tool according to any one of the first to twelfth aspects, wherein the control unit performs the second operation based on the characteristic value acquired in the first operation. Is set using fuzzy inference.

Here, the above-described DC motor optimization control is performed using fuzzy inference.
Thereby, the optimization control of the DC motor using the difference between the target rotation speed and the actual rotation speed acquired in the first operation described above, the average current, the current ripple, and the like is performed by using fuzzy inference. The control conditions can be optimized according to the material of the work material to be worked.

A power tool control method according to a fourteenth invention is the power tool control method according to any one of the first to thirteenth inventions, and wherein the electric tool control method according to any one of claims 1 to 13 is provided. A method for controlling a tool, comprising the following steps. A step of rotating the DC motor under a preset control condition in the first operation. In a first operation, a step of obtaining a characteristic value of the DC motor. Adjusting a control condition of the DC motor in a second operation of the same type as the first operation, which is performed subsequent to the first operation, based on the characteristic value acquired in the first operation. In the second operation, a step of rotating the DC motor according to the adjusted control condition.

Here, for example, when the same kind of work is continuously performed on the same kind of work material using an electric tool used in various kinds of work such as screw tightening and drilling, the DC power acquired in the first work is used. Based on the characteristic values related to the motor, the control condition of the DC motor in the second operation performed after the first operation is optimized.
That is, in the power tool of the present invention, when the same type of work is continuously performed on the same type of processing material, the characteristic values such as the rotation speed and the current value of the DC motor acquired at the time of the operation in the first operation are used. Then, the control condition for the second operation is set so that the second operation in which the same type of operation is performed next is performed under the optimum control condition.

Here, the same kind of work using the electric tool includes, for example, screw tightening, screw loosening, drilling, and the like. Examples of the same type of processing material include various materials such as metal, wood, resin, and rubber.
In addition, the first work and the second work are not limited to the first work and the second work in a series of the same kind of work that is continuously performed. For example, the fifth work and the sixth work are performed. It is sufficient that the work is merely in-context work, such as the second work.

The optimization of the control condition may be repeatedly performed for each operation, may be performed only between the first operation and the second operation of the series of operations, It may be carried out every time the predetermined number of times is reached.
Further, as the characteristic value related to the DC motor, for example, the operation amount of the speed setting unit that rotationally drives the DC motor, the target rotation speed of the DC motor corresponding to this, the actual rotation speed, the battery voltage, the current value flowing through the DC motor , DC motor temperature, and the like.

Accordingly, when the same type of work is continuously performed on the same type of processing material using the electric tool, the first type of operation is performed following the first type of operation based on the characteristic values of the DC motor acquired in the first operation. It is possible to optimize the control condition of the DC motor in the performed second operation.
Therefore, it is not necessary to change the setting to a special mode for the learning operation to optimize the control condition of the DC motor. Can be

The control method for a power tool according to a fifteenth invention is the control method for a power tool according to the fourteenth invention, wherein the characteristic value includes a target rotation speed of the DC motor with respect to an operation amount of the speed setting unit, and a DC motor. The difference from the actual rotation speed is included.
Here, the difference between the target rotation speed of the DC motor with respect to the operation amount of the speed setting unit and the actual rotation speed detected by the detection unit is used as the characteristic value used in the optimization control of the control condition of the DC motor. .

Specifically, when the difference between the target rotation speed and the actual rotation speed of the DC motor acquired in the first operation is large, the control condition of the DC motor is adjusted to be large in order to reduce the difference. On the other hand, when the difference is small, the control condition of the DC motor is slightly adjusted to further reduce the difference.
Thereby, it is possible to optimize the control condition of the DC motor at the time of performing the second operation according to the magnitude of the difference between the target rotation speed and the actual rotation speed of the DC motor acquired in the first operation. it can.

A control method for a power tool according to a sixteenth invention is the control method for a power tool according to the fifteenth invention, wherein, in the second operation, the operation amount of the speed setting unit and the target rotation are adjusted according to the magnitude of the difference. Rewrite the table showing the relationship with speed.
Here, in the DC motor optimization control using the difference between the target rotation speed and the actual rotation speed of the DC motor acquired in the first operation described above, the operation of the speed setting unit is performed in accordance with the magnitude of the difference. The table showing the relationship between the amount and the target rotation speed is rewritten.

Specifically, when the difference between the target rotation speed of the DC motor and the actual rotation speed obtained in the first work is large, for example, in order to reduce the difference, for example, the operation amount of the speed setting unit and the target The inclination of the table indicating the relationship with the rotation speed is adjusted to be large. On the other hand, when the difference is small, for example, the inclination of the table is slightly adjusted to further reduce the difference.
Thereby, for example, according to the magnitude of the difference between the target rotation speed and the actual rotation speed of the DC motor acquired in the first operation, for example, a table of the relationship between the operation amount of the speed setting unit and the target rotation speed is displayed. By adjusting the inclination and the like, the second operation can be performed under optimal conditions.

A control method for a power tool according to a seventeenth invention is the control method for a power tool according to the fifteenth or sixteenth invention, and is output to the switching circuit in the second operation according to the magnitude of the difference. Adjust the control gain.
Here, in the DC motor optimization control using the difference between the target rotation speed and the actual rotation speed of the DC motor acquired in the first operation described above, the DC motor output is output to the switching circuit in accordance with the magnitude of the difference. Control gain (proportional gain, integral gain, derivative gain, etc. in speed feedback control).

Specifically, when the difference between the target rotation speed and the actual rotation speed of the DC motor acquired in the first operation is large, for example, a control gain output to a switching circuit is used to reduce the difference. Adjust to a large value. On the other hand, when the difference is small, for example, the control gain is slightly adjusted to further reduce the difference.
Thereby, the control gain output to the switching circuit is adjusted in accordance with the magnitude of the difference between the target rotation speed and the actual rotation speed of the DC motor acquired in the first operation, so that the optimum condition can be obtained. A second operation can be performed.
The adjustment using the control gain may be performed in combination with the above-described control for adjusting the inclination of the table indicating the relationship between the operation amount of the speed setting unit and the target rotation speed, or may be performed independently.

An electric tool control method according to an eighteenth aspect of the present invention is the electric tool control method according to any one of the fourteenth to seventeenth aspects, wherein the characteristic value flows to a circuit connected to the DC motor. At least one of an average current and a current ripple calculated based on the current value measured by the current measurement unit that measures the current is included.

Here, at least one of the average current and the current ripple calculated based on the current value measured by the current measurement unit is used as the characteristic value used in the optimization control of the control condition of the DC motor.
Thereby, the control condition of the DC motor when performing the second operation can be optimized according to at least one of the average current and the current ripple acquired in the first operation.

A power tool control method according to a nineteenth aspect is the power tool control method according to the eighteenth aspect, wherein, in the second operation, the operation of the speed setting unit is performed according to at least one of the average current and the current ripple. The table indicating the target rotation speed of the DC motor corresponding to the amount is rewritten.
Here, in the DC motor optimization control using at least one of the average current and the current ripple acquired in the above-described first operation, the operation amount of the speed setting unit according to the value of the average current and / or the current ripple. The table showing the relationship between the target rotation speed and the target rotation speed is rewritten.
Thereby, for example, the relationship between the operation amount of the speed setting unit and the target rotation speed is determined in accordance with the average current of the current flowing in the circuit connected to the DC motor and / or the value of the current ripple obtained in the first operation. The second operation can be performed under optimal conditions by adjusting the inclination of the table shown.

A control method for a power tool according to a twentieth invention is the control method for a power tool according to the eighteenth or nineteenth invention, wherein, in the second operation, the switching circuit is controlled according to at least one of an average current and a current ripple. Adjust the control gain output to.

Here, in the optimization control of the DC motor using at least one of the average current and the current ripple acquired in the first operation described above, the DC current is output to the switching circuit according to the value of the average current and / or the current ripple. Adjust the control gain.
Thereby, for example, by adjusting the control gain output to the switching circuit according to the average current and / or the current ripple value of the current flowing in the circuit connected to the DC motor acquired in the first operation, The second operation can be performed under optimal conditions.
The adjustment by the control gain may be performed in combination with the above-described control for adjusting the inclination of the table indicating the relationship between the operation amount of the speed setting unit and the target rotation speed, or may be performed independently. .

A power tool control method according to a twenty-first aspect is the power tool control method according to any one of the fourteenth to twentieth aspects, wherein the control method is based on a DC motor characteristic value acquired in the first operation. And estimating the material of the processing material.

Here, from the characteristic values of the DC data acquired in the first operation, the material of the processing material to be screwed, loosened, drilled, or the like is estimated.
Specifically, for example, when the difference between the actual rotation speed detected by the detection unit and the target rotation speed of the DC motor with respect to the operation amount of the speed setting unit described above is large on the minus side, the processing material is a hard material. It is presumed that there is. Conversely, when the difference is large on the positive side, it is estimated that the processed material is a soft material.
Thus, by estimating the material of the processing material using one or more of the characteristic value such as the difference between the actual rotation speed with respect to the target rotation speed, the average current of the DC motor, and the current ripple, the second work can be performed. , More optimal control conditions can be set.

電動 A power tool control method according to a twenty-second aspect is the power tool control method according to the twenty-first aspect, wherein the material of the working material includes hardness and homogeneity.

Here, the hardness and homogeneity of the material are listed as the material of the estimated processing material.
This makes it possible to set optimal control conditions in consideration of the hardness and homogeneity of the material to be worked, when performing the same kind of work continuously.
A control program for a power tool according to a twenty-third invention is a control program for a power tool according to any one of the first to thirteenth inventions, wherein a control method for a power tool including the following steps is provided to a computer. Let it run. A step of rotating the DC motor under a preset control condition in the first operation. In a first operation, a step of obtaining a characteristic value of the DC motor. Adjusting a control condition of the DC motor in a second operation of the same type as the first operation, which is performed subsequent to the first operation, based on the characteristic value acquired in the first operation. In the second operation, a step of rotating the DC motor according to the adjusted control condition.

Here, for example, when the same kind of work is continuously performed on the same kind of work material using an electric tool used in various kinds of work such as screw tightening and drilling, the DC power acquired in the first work is used. Based on the characteristic values related to the motor, the control condition of the DC motor in the second operation performed after the first operation is optimized.
That is, in the power tool of the present invention, when the same type of work is continuously performed on the same type of processing material, the characteristic values such as the rotation speed and the current value of the DC motor acquired at the time of the operation in the first operation are used. Then, the control condition for the second operation is set so that the second operation in which the same type of operation is performed next is performed under the optimum control condition.

Here, the same kind of work using the electric tool includes, for example, screw tightening, screw loosening, drilling, and the like. Examples of the same type of processing material include various materials such as metal, wood, resin, and rubber.
In addition, the first work and the second work are not limited to the first work and the second work in a series of the same kind of work that is continuously performed. For example, the fifth work and the sixth work are performed. It is sufficient that the work is merely in-context work, such as the second work.

The optimization of the control condition may be repeatedly performed for each operation, may be performed only between the first operation and the second operation of the series of operations, It may be carried out every time the predetermined number of times is reached.
Further, as the characteristic value related to the DC motor, for example, the operation amount of the speed setting unit that rotationally drives the DC motor, the target rotation speed of the DC motor corresponding to this, the actual rotation speed, the battery voltage, the current value flowing through the DC motor , DC motor temperature, and the like.

Accordingly, when the same type of work is continuously performed on the same type of processing material using the electric tool, the first type of operation is performed following the first type of operation based on the characteristic values of the DC motor acquired in the first operation. It is possible to optimize the control condition of the DC motor in the performed second operation.
Therefore, it is not necessary to change the setting to a special mode for the learning operation to optimize the control condition of the DC motor. Can be
(The invention's effect)
ADVANTAGE OF THE INVENTION According to the electric power tool which concerns on this invention, an optimal motor control condition can be set with a simple operation | movement.

FIG. 1 is a control block diagram illustrating a configuration of a power tool according to an embodiment of the present invention. 3A is a table showing a relationship between an operation amount of a trigger switch and a target rotation speed stored in a storage unit of the power tool in FIG. 1; (B) is the graph. 3 is a flowchart showing a flow of optimization control using the electric tool of FIG. 1. 4 is a flowchart showing a flow of an initial setting process of the flowchart of FIG. 3; (A) to (c) show three characteristic values (speed deviation, current ripple, and average value) acquired during the first operation when fuzzy inference is applied to the optimization process of the motor control conditions of the power tool in FIG. 4 is a graph showing a membership function regarding current (current) and properties (hardness, homogeneity) of a processed material. (A) is a graph which shows the membership function regarding the change of the inclination of a target speed table. (B) is a graph which shows the membership function regarding change of PI gain. 5A to 5C are graphs showing examples in which specific numerical values are applied to the characteristic values of the graphs showing the membership functions of FIGS. 5A to 5C. 6A and 6B are graphs showing examples in which specific numerical values are applied to the membership functions shown in FIGS. 6A and 6B to form a graphic.

The power tool 10 according to one embodiment of the present invention will be described below with reference to FIGS. 1 to 8B.
Here, in the present embodiment, a motor for continuously performing the same kind of operation, such as a drilling operation, among the drilling operations such as screw tightening, screw loosening, and drilling using the power tool 10 is described. Will be described below.

電動 The power tool 10 according to the present embodiment rotates a tip tool such as a driver or a drill mounted on the tip portion by a brushless motor (motor 16) supplied with power from the battery 11. As shown in FIG. 1, the power tool 10 includes a battery (power supply unit) 11, a trigger switch (speed setting unit) 12, a switching circuit (gate circuit 13, an FET (Field Effect Transistor) array 14), and a current detection resistor. 15, a motor 16, a magnetic pole position detection circuit 17, a reset switch 18, and a control unit 20.

The battery (power supply unit) 11 is, for example, a replaceable rechargeable battery mounted on a grip portion of the power tool 10, and is used as a power source of the power tool 10. Further, as shown in FIG. 1, the battery 11 is connected to the FET array 14 and the control unit 20, and supplies power to each.
Although not shown, a constant-voltage power supply for generating a constant-voltage power supply in which the voltage of the battery 11 is reduced to a predetermined constant voltage Vcc (for example, 5 V) is provided in the driving device of the electric tool 10. I have. The constant voltage power supply (Vcc) is used as a power supply for operating a predetermined circuit in the driving device including the control unit 20.

The trigger switch (speed setting unit) 12 is an operation part for rotating the motor 16 of the electric tool 10 at a rotation speed according to the operation amount (retraction amount), and as shown in FIG. Including vessel. The variable resistor has one end connected to the constant voltage Vcc and the other end connected to the ground line. The trigger switch 12 is configured as a so-called potentiometer, and inputs a voltage (trigger operation amount signal) corresponding to the operation amount of the trigger switch 12 to the trigger operation amount signal input port of the control unit 20 using the constant voltage Vcc as a power supply. I do.

The gate circuit 13 constitutes a switching circuit together with the FET array 14, and is provided for individually turning on / off each switching element 14a in the FET array 14, as shown in FIG. The six gate drivers 13a included in the gate circuit 13 are controlled by the control unit 20.
As shown in FIG. 1, the FET array 14 connects a terminal of each phase of the motor 16 to the positive terminal of the battery 11 and a terminal of each phase of the motor 16 and the negative terminal of the battery 11. It is configured as a half-bridge circuit including six switching elements 14a including a low-side switch to be connected.

Further, the switching element 14a constituting the FET array 14 is constituted by an n-channel FET. Each switching element 14a is connected to a gate circuit 13 that turns on each switching element 14a by applying a drive voltage equal to or greater than a threshold value between the gate and the source.
The current detection resistor 15 is provided for detecting a current flowing through the motor 16, and is connected to a current calculation unit 25 described later, as shown in FIG.

As shown in FIG. 1, the motor 16 is configured by a three-phase (U-phase, V-phase, W-phase) brushless motor, and a terminal of each phase is connected to a battery 11 as a DC power supply via an FET array 14. It is connected to the. The motor 16 has three coils 16a, three Hall ICs (or Hall elements) 16b, and a rotor 16c.
The coil 16a is provided for each of three phases (U-phase, V-phase, and W-phase), and is located at a position close to the rotor 16c on the rotor side and on the stator side.

The Hall IC 16b outputs a pulse signal to the control unit 20 according to the rotation position of the motor 16 detected by the magnetic pole position detection circuit 17 (that is, each time the motor 16 rotates a predetermined number).
The rotor 16c is equipped with a tip tool such as a drill, and as shown in FIG. 1, is configured by embedding a permanent magnet including a pair of N poles and a pair of S poles. And are arranged facing each other.

As shown in FIG. 1, the magnetic pole position detection circuit 17 detects the positional relationship between the three-phase (U-phase, V-phase, and W-phase) coils 16a and the rotor 16c based on the output signals of the three Hall ICs 16b. I do. Then, the magnetic pole position detection circuit 17 transmits the detected result to the control unit 20 (current speed calculation unit 23).
The reset switch 18 is, for example, a button-type switch provided on the outer surface of the power tool 10, and when operated by a user, as shown in FIG. Send

The control unit 20 controls the rotational driving of the motor 16 according to the control conditions when the motor 16 of the electric tool 10 is rotationally driven.
In the power tool 10 of the present embodiment, the control unit 20 calculates the rotation position and the current speed of the motor 16 based on a pulse signal from the magnetic pole position detection circuit 17 that detects the rotation position of the motor 16. Then, the control unit 20 performs PWM (Pulse Width Modulation) control on the motor 16 so that the current rotation speed matches a target rotation speed determined by the operation amount of the trigger switch 12.

Here, when the trigger switch 12 is turned on by operating the trigger switch 12, the control unit 20 controls each switching element 14 a in the FET array 14 via the gate circuit 13 based on the detection signal from the Hall IC 16 b included in the motor 16. Is turned ON / OFF. Thus, the control unit 20 controls the current supplied to the coil 16a of each phase of the motor 16 to rotate the motor 16 in a predetermined direction at a predetermined rotation speed. Then, the control unit 20 inputs a control signal for driving each switching element 14a to the gate circuit 13.

The trigger operation amount signal captured by the control unit 20 is used by the table reference unit 21 to output a target rotation speed table indicating a target rotation speed corresponding to the operation amount of the trigger switch 12 (FIGS. 2A and 2B). Is converted to the target rotation speed.
FIG. 2A shows an example of a target rotation speed table showing the relationship between the operation amount of the trigger switch 12 and the target rotation speed. As shown in the graph of FIG. 2B, the target rotation speed of the motor 16 with respect to the operation amount of the trigger switch 12 is set to increase (partially unchanged) as the operation amount increases.

In the power tool 10 of the present embodiment, with such a configuration, when the user pulls the trigger switch 12 (for example, when the user pulls a small amount), the target rotation speed is set according to the trigger operation amount signal from the variable resistor. You. Then, the control unit 20 starts the PWM control of the motor 16 so as to rotate the motor 16 at the target rotation speed. That is, the drive duty ratio of the FET array 14 is adjusted so that the rotation speed increases as the operation amount of the trigger switch 12 increases (that is, the drive duty ratio increases).

More specifically, as shown in FIG. 1, the control unit 20 includes a table reference unit 21, an operation amount calculation unit 22, a current speed calculation unit (detection unit) 23, a correction coefficient calculation unit 24, a current calculation unit 25, A storage unit 26 and a PWM signal generation unit 27 are provided.
The table reference unit 21 corresponds to the current operation amount of the trigger switch 12 with reference to the target rotation speed table (graph) stored in the storage unit 26 (see FIGS. 2A and 2B). Find the target rotation speed. Then, the table reference unit 21 transmits the target rotation speed to the operation amount calculation unit 22.

Further, the table reference unit 21 receives a table correction coefficient from a correction coefficient calculation unit 24 described later and corrects a target rotation speed table (for example, a gradient of a graph). The correction processing of the target rotation speed table will be described later in detail.
The operation amount calculation unit 22 receives the target rotation speed of the motor 16 corresponding to the operation amount of the trigger switch 12 received from the table reference unit 21, and causes the PWM signal generation unit to rotate the motor 16 at the target rotation speed. The duty ratio is transmitted to 27. Further, the operation amount calculation unit 22 calculates a difference between the actual rotation speed of the motor 16 received from the current speed calculation unit 23 and the target rotation speed, and transmits the difference to the storage unit 26.

The current speed calculation unit (detection unit) 23 is connected to the magnetic pole position detection circuit 17 and calculates the current actual rotation speed of the motor 16 based on the detection result received from the magnetic pole position detection circuit 17. Then, the current speed calculation unit 23 transmits the calculated actual rotation speed to the operation amount calculation unit 22.
The correction coefficient calculation unit 24 calculates a difference between the target rotation speed of the motor 16 corresponding to the operation amount of the trigger switch 12 received from the table reference unit 21 and the actual rotation speed of the motor 16 received from the current speed calculation unit 23 ( Speed deviation) is read out from the storage unit 26. Then, the correction coefficient calculation unit 24 calculates a correction coefficient for correcting the target rotation speed table, and transmits the correction coefficient to the table reference unit 21. Further, the correction coefficient calculator 24 transmits the correction coefficient and the control gain adjusted for feedback control to the manipulated variable calculator 22.

In the power tool 10 according to the present embodiment, in order to optimize the control conditions for the same type of work (second work) performed after the current work (first work), the power is output from the correction coefficient calculator 24. A correction coefficient for table correction and a control gain for feedback control are used.
The current calculation unit 25 is connected between the FET array 14 and the current detection resistor 15 and calculates a current flowing through the motor 16. Then, the current calculation unit 25 transmits the characteristic values (average current and current ripple described later) calculated from the calculation result to the storage unit 26.

The storage unit 26 stores the speed deviation received from the operation amount calculation unit 22, the average current and the current ripple received from the current calculation unit 25, and a control program of the power tool 10 described later.
The PWM signal generation unit 27 calculates the difference (speed deviation) between the target rotation speed received from the table reference unit 21 and the actual rotation speed of the motor 16 received from the current speed calculation unit 23 by adding PI compensation. The operation amount (the duty of the PWM output) is output to the switching circuit (gate circuit 13 and FET array 14).

In addition, the PWM signal generation unit 27 uses the characteristic values (the magnitude of the difference (speed difference), the average current, the current ripple, and the like) acquired in the current work (first work) to perform the current work (the first work). The control conditions of the motor 16 in the operation (second operation) performed after the first operation are optimized. Note that the process of optimizing the control condition of the second operation will be described in detail later.
Here, when shifting from the work of the same kind (for example, drilling) that has been continuously performed to another kind of work (for example, screw tightening and screw loosening), the reset switch 18 is operated by the user. Is operated. As a result, a reset signal is transmitted from the reset switch 18 to the correction coefficient calculation unit 24, and the optimization control for the second operation, such as correction (rewriting) of the target rotation speed table and adjustment of the control gain, which will be described later, is reset. Is returned to the initial state.

<Calculation of operation amount based on target rotation speed and current rotation speed>
In the power tool 10 of the present embodiment, the operation amount (drive duty ratio) of the trigger switch 12 is calculated by the following control (proportional control, integral control, differential control, etc.).
The proportional control (P control) is a control in which an operation amount is obtained by multiplying a difference (speed deviation) between a target rotation speed and the current rotation speed of the motor 16 by a proportional control gain KP. The operation amount is calculated by 1).

Manipulated variable = proportional control gain KP x deviation N0 (1)
The integral control (I control) is a control in which an accumulated amount of a difference (speed deviation) between the target rotational speed and the current rotational speed of the motor 16 is multiplied by an integral control gain KI to obtain an operation amount. The operation amount is calculated by Expression (2).
Manipulated variable = integral control gain KI x (current deviation N0 + previous deviation N1 + two-time previous deviation N2) (2)
The differential control (D control) is obtained by multiplying a difference between a current difference (speed deviation) between the target rotation speed and the current rotation speed of the motor 16 and a previous difference (speed deviation) by a differential control gain KD. In this control, the operation amount is calculated by the following equation (3).

Manipulated variable = differential control gain KD x (current speed deviation N0-previous speed deviation N1) (3)
The proportional + integral control (PI control) is a control in which the above-described proportional control and integral control are combined, and is an operation obtained by using the proportional control equation (1) and the integral control equation (2), respectively. The operation amount is calculated by adding the amounts and adding / subtracting the current operation amount.

The proportional + integral + differential control (PID control) is a control in which the proportional control, the integral control, and the differential control are combined, and uses the equations (1) to (3) of the proportional control, the integral control, and the differential control. The operation amount is calculated by adding the operation amounts obtained respectively and adding / subtracting the current operation amount.
Here, the integral control (I control) is a control for reducing an error with respect to a target speed, and is performed to improve speed accuracy. The differential control improves the response of the control, and is performed to cope with a sudden load change when the power tool 10 is used.

It should be noted that the optimum values of the proportional control gain KP, the integral control gain KI, and the differential control gain KD need to be obtained in advance by experiments or the like.
<Optimization control of motor 16>
In the power tool 10 of the present embodiment, the optimization control of the motor 16 in the same type of work (second work) performed after the currently performed work (first work) is performed according to the flowchart shown in FIG. I do.

That is, as shown in the flowchart of FIG. 3, in step S1, for example, when the charged battery 11 is connected to the power tool 10, the initial setting is performed.
The initial setting in step S1 is performed according to the flowchart shown in FIG. In the initial setting, the control unit 20 includes the control gains KP, KI, and KD described above, the relational expression between the operation amount of the trigger switch 12 and the target rotation speed, and the counter. Various initialization processes required for the operation are performed.

Specifically, as shown in FIG. 4, in step S11, the target rotation speed table is reset to return to the default setting table.
Next, in step S12, the operation amount adjusted based on the characteristic values obtained in the previous and previous work is reset.
Next, in step S13, the control gain is reset. Specifically, the above-described KP = 0.80 and KI = 0.02, and the initialization process ends.

Subsequently, in step S2 of the flowchart shown in FIG. 3, after the initial setting in step S1, the control unit 20 waits until the trigger switch 12 is turned on (that is, the trigger switch 12 is operated), and When 12 is operated, the process proceeds to step S3.
Next, in step S3, when the trigger switch 12 is operated in step S2, the control unit 20 reads the operation amount of the trigger switch 12. That is, the potential divided by the trigger switch 12 is taken into the control unit 20 via an A / D converter (not shown).

Next, in step S4, the target rotation speed of the motor 16 is determined with reference to a table (see FIG. 2A) showing the relationship between the operation amount of the trigger switch 12 and the target rotation speed. The calculation of the target rotation speed of the motor 16 may be performed using a relational expression between the operation amount of the trigger switch 12 and the target rotation speed.
Next, in step S5, the control unit 20 obtains the current rotation speed of the motor 16. More specifically, the current speed calculation unit 23 of the control unit 20 calculates the current rotation speed of the motor 16 using the signal cycle of the Hall IC 16b received from the magnetic pole position detection circuit 17, and the like.

Next, in step S6, the control unit 20 determines whether the current rotation speed calculated by the current speed calculation unit 23 is equal to the target rotation speed corresponding to the operation amount of the trigger switch 12 obtained by referring to the target rotation speed table. Calculate the difference (speed deviation) from the rotation speed. More specifically, the operation amount calculation unit 22 of the control unit 20 calculates a difference between the target rotation speed obtained from the table reference unit 21 and the current rotation speed of the motor 16 obtained from the current speed calculation unit 23, The data is transmitted to the storage unit 26. Then, the storage unit 26 stores the value of the difference as one of the characteristic values used when performing the optimization control.

Next, in step S7, the control unit 20 applies a PI (proportional integral) compensation to the difference (speed deviation) between the current rotation speed of the motor 16 and the target rotation speed, and thereby performs an operation amount (drive duty ratio). ) Is calculated and output to the gate circuit 13 via the PWM signal generation unit 27.
In step S7, the immediately preceding work has been completed during the same kind of work that is continuously performed, and the storage unit 26 stores the target rotational speed table and the adjusted table and values of the control gain. If so, the output to the gate circuit 13 is set using the adjusted table and control gain.

In the power tool 10 of the present embodiment, the target rotation speed table and the target rotation speed table are obtained by using the characteristic values obtained in the immediately preceding operation (first operation) in the same type of operation performed continuously by such processing. By adjusting the control gain, it is possible to make the control conditions of the motor 16 at the time of the succeeding work (second work) more suitable than the immediately preceding work (first work).
Then, each time one operation (the first operation) is performed, these operations are repeatedly performed for the next operation of the same type (the second operation), so that the same type of operation such as drilling is repeatedly performed. In this case, the control conditions of the motor 16 can be optimized.

Next, in step S8, if the state in which the trigger switch 12 is operated (ON state) is continued, the process returns to step S2, and the processing from reading the operation amount is repeated again. On the other hand, when the trigger switch 12 is in the open state (OFF state) in step S8, in step S9, the PWM signal generation unit 27 of the control unit 20 outputs a signal indicating that the operation amount Duty = 0. To the gate circuit 13 to stop the rotation of the motor 16.

Next, in step S10, after the rotation of the motor 16 is stopped, the target rotation speed is optimized in order to optimize the control conditions of the motor 16 when performing the same type of work (second work) to be subsequently performed. Adjust the table and control gain.
After the target rotational speed table and the control gain are adjusted in step S10, the processes in step S2 and thereafter are repeatedly performed.

<Adjustment of target rotation speed table and control gain>
In the power tool 10 of the present embodiment, the control condition of the motor 16 when performing the same kind of work (second work) that is continuously performed after the previous work (first work) is optimized. Therefore, the target rotation speed table and the control gain are adjusted. In the present embodiment, for example, fuzzy logic is applied to the adjustment of the target rotation speed table and the control gain. Hereinafter, an example in which fuzzy logic is applied to optimization control of the motor 16 will be described.

First, FIG. 5 shows a relationship between characteristic values (difference (speed deviation), average current, current ripple) of the motor 16 obtained from a series of operations in the immediately preceding operation (first operation) and properties of a processing material. The membership functions shown in FIGS. 5A to 5C are set.
Note that the membership functions shown in FIGS. 5A and 5C indicate the hardness (softness) of the processed material in terms of the degree of hardness (softness) (0 to 1.0). It is. The membership function shown in FIG. 5 (b) indicates the homogeneity (heterogeneity) of the processed material by the degree of homogeneity (heterogeneity) (0 to 1.0).

By using the membership function of fuzzy inference in this way, the properties (hardness, homogeneity) of the work material can be linked to the property values (difference, average current, current ripple) obtained during the actual work. it can.
In the present embodiment, when performing the optimization control of the motor 16, three characteristic values of a difference (speed deviation) between the target rotation speed and the actual rotation speed of the motor 16, an average current flowing through the motor 16, and a current ripple. Are used in combination.

Specifically, FIG. 5A shows the relationship between the hardness (solid line) and the softness (broken line) of the processed material with respect to the difference (speed deviation) between the target rotation speed and the actual rotation speed of the motor 16. This is indicated by the membership function.
That is, the membership function of the speed deviation shown in FIG. 5A shows that the resistance during the processing is large until the work material has a predetermined hardness (1.0), so that the speed deviation is linearly reduced to −20%. Become smaller. Similarly, in the membership function, since the resistance during processing is small until the processing material has a predetermined softness (1.0), the speed deviation increases linearly up to + 20%.

FIG. 5B shows the relationship between the current ripple and the homogeneity (solid line) and inhomogeneity (dashed line) of the processed material by a membership function.
That is, in the membership function of the current ripple shown in FIG. 5B, if the homogeneity of the processing material is high, the variation in resistance at the time of processing is small. If the homogeneity is high, the variation in resistance at the time of processing increases, so that the current ripple is 20% or more.

FIG. 5C shows the relationship between the average current of the motor 16 and the softness (solid line) and hardness (dashed line) of the processed material by a membership function.
That is, the membership function of the average current shown in FIG. 5 (c) is a function indicating the hardness of the processing material as in FIG. 5 (a), and the processing material has a predetermined softness (1.0). Since the resistance during processing is small, the average current decreases linearly from 20 A to 10 A. Similarly, in the membership function, the average current increases linearly from 20 A to 30 A because the resistance during processing is large until the processing material has a predetermined hardness (1.0).

In the power tool 10 according to the present embodiment, the following eight fuzzy inference rules (1) to (8) are used for the method of adjusting the target rotation speed table and the control gain from the characteristics (hardness, homogeneity) of the work material. Enact.
(1) "If the work material is considerably hard and non-homogeneous, lower the inclination of the target rotation speed table."
(2) "If the processing material is fairly hard and homogeneous, the target rotation speed table remains the same."
(3) "If the processing material is quite hard and non-homogeneous, lower the control gain (PI gain)."
(4) "If the processing material is fairly hard and homogeneous, increase the control gain (PI gain)."
(5) "If the processing material is soft and homogeneous, raise the inclination of the target rotation speed table."
(6) "If the processing material is soft and inhomogeneous, raise the inclination of the target rotation speed table."
(7) "If the processing material is soft and homogeneous, the control gain (PI gain) remains unchanged"
(8) "If the processing material is soft and non-homogeneous, the control gain (PI gain) remains unchanged"
In the above eight rules of fuzzy inference (1) to (8), “if, if” is the antecedent part, and “to” is the consequent part.

Next, the membership functions shown in FIGS. 6A and 6B are set for the consequent part.
The membership function shown in FIG. 6A is based on a membership function indicating the relationship between the three characteristic values shown in FIG. 5A to FIG. The processing of "lower" (dashed-dotted line), "as is" (solid line), and "raise" (broken line) the slope of the graph is shown as a function.

The membership function shown in FIG. 6B is based on a control gain (PI) based on a membership function showing the relationship between the three characteristic values shown in FIGS. 5A to 5C and the characteristics of the work material. The processing of "decrease" (gain and dash-dot line), "as is" (solid line), and "increase" (dashed line) is shown as a function.
Here, as an example of each actually acquired characteristic value, the target rotation speed table and the control gain (PI gain) when “speed deviation: −13%, current ripple: 5%, average current: 25 A” are set. The method of adjusting is described quantitatively.

First, since the difference (speed deviation) between the target rotation speed and the actual rotation speed of the motor 16 is −13%, the degree of conformity of the “very hard” element is determined by the membership function shown in FIG. The fitness of the "soft" element is 0.6 points, and the fitness is 0.1 point.
Similarly, since the current ripple is 5%, the degree of conformity of the “homogeneous” element is 1.0 point by the membership function shown in FIG. 7B. Then, since the average current is 25 A, the degree of conformity of the “very hard” element is 0.5 point by the membership function shown in FIG. 7C.

Thereby, in the power tool 10 of the present embodiment, using the above-mentioned three characteristic values (difference (speed deviation), average current, and current ripple) acquired in the previous operation (first operation), The material (hardness, homogeneity) can be estimated.
Next, the characteristics of the processed material are applied to the fuzzy inference rules (1) to (8) established above.

When two different degrees of matching are obtained with the same element, the larger numerical value is used, and the smaller numerical value is used between different elements.
According to the rule (1), as described above, the fitness degree of the element which is “very hard” by the membership function is obtained as two points of 0.6 point and 0.5 point. Adopted. The degree of conformity of the “heterogeneous” element was 0 point.

Since the smaller numerical value of both elements is 0 point, "the tilt of the target rotational speed table does nothing".
(1) "If it is quite hard (0.6 (> 0.5)) and non-uniform (0), lower the inclination of the target rotation speed table."
-> Do nothing The same operation is repeated for rules (2) to (8).
(2) "If it is quite hard (0.6 (> 0.5)) and homogeneous (1), the target rotation speed table remains as it is"
-> The inclination of the target rotation speed table remains unchanged (0.6)
(3) "If it is quite hard (0.6 (> 0.5)) and non-homogeneous (0), lower the control gain (PI gain)."
-> Do nothing (4) "If it is quite hard (0.6 (> 0.5)) and homogeneous (1), increase the control gain (PI gain)."
-> Increase control gain (PI gain) (increase to 0.6)
(5) "If it is soft (0.1) and homogeneous (1), increase the inclination of the target rotation speed table"
-> Increase the inclination of the target rotation speed table (increase by 0.1)
(6) "If soft (0.1) and inhomogeneous (0), increase the tilt of the target rotation speed table"
-> Do nothing (7) "If soft (0.1) and homogeneous (1), control gain (PI gain) remains as it is"
-> The control gain (PI gain) remains unchanged (0.1)
(8) "If it is soft (0.1) and heterogeneous (0), the control gain (PI gain) remains as it is"
-> Do Nothing Next, as shown in FIGS. 8A and 8B, the numerical values of the consequent parts of each of the rules (1) to (8) are graphically represented.

Since the consequent part of the rule (2) has a degree of conformity of 0.6 points of “the target rotational speed table is as it is”, the membership function “change of the target speed table inclination” has a height of “as is” of 0.6. Draw a line there.
Similarly, for rules (4), (5), and (7), a line is drawn on the membership function. As for rules (1), (3) and (6), nothing is performed because the antecedent part is 0.

Finally, the composite figure in the hatched portion is digitized. This is called defuzzification (defuzzification). Specifically, the center of gravity of the composite figure (hatched portion) is obtained and set as a numerical value.
As for “adjustment of the inclination of the target rotation speed table”, as shown in FIG. 8A, a weight of 0.6 is applied to × 1.0, and a weight of 0.1 is applied to × (1.0 + 1.25) / 2. Therefore, the center of gravity is
1 + 0.125 / 7 = 1.018
It becomes.

Similarly, regarding “adjustment of control gain (PI gain)”, the center of gravity is 1.429, as shown in FIG. 8B.
Therefore, when the trigger switch 12 is operated in the next operation of the same type (second operation), the target rotation speed is determined based on the characteristic value obtained in the previous operation (first operation). The inclination of the table is 1.018 times, and the control gain (PI gain) is 1.429 times.

As described above, the power tool 10 according to the present embodiment is set for the next same type of work (second work) based on the work history (characteristic value) obtained in the work (first work) up to that time. Control parameters (parameters) to be adjusted (optimized).
Thereby, when repeating the same kind of work such as drilling, for example, the user can perform a later work under the optimized control condition. Therefore, the work efficiency is improved and the power tool 10 is easy to use, and the power consumption of the power tool 10 can be reduced.

Further, since the control condition of the motor 16 is automatically rewritten to a condition suitable for each work, work mistakes (failures) can be reduced, work yield can be improved, and loss of work material can be reduced. .
Further, the arithmetic processing in the present optimization control is performed during a continuous work and an idle time of the work. Therefore, the load on the control unit 20 is light and can be realized at low cost.

Furthermore, for example, when the operation content is switched from the drilling operation to the screw tightening operation, the user operates the reset switch 18 to discard the learning content accumulated up to that time and reset the initial state. (For example, at the time of factory shipment). Therefore, when performing another type of work (screw tightening), the control of the subsequently performed screw tightening work (second work) is again performed using each characteristic value obtained by the first work. Conditions can be optimized. As a result, in each type of work, control conditions suitable for each type of work can be set each time the work is performed.

Further, in the power tool 10 of the present embodiment, when performing the same kind of work continuously, the data (the operation amount of the trigger switch 12, the operation amount Duty to the motor driver, the battery voltage , Motor speed, motor current, motor temperature, etc.), the material (hardness, homogeneity, etc.) of the processing material can be inferred. Therefore, the control condition (control parameter) optimized according to the material of the processing material can be automatically set for the operation to be performed subsequently (the second operation).

As a result, when repeatedly performing the same kind of work, the user can automatically perform the optimum control condition (control) by simply performing the normal work repeatedly without performing any special mode setting such as the learning mode. Parameter), it is possible to work comfortably.
[Other embodiments]
As mentioned above, although one Embodiment of this invention was described, this invention is not limited to the said Embodiment, A various change is possible within the range which does not deviate from the summary of this invention.

(A)
In the above embodiment, the adjustment of the target rotation speed table and the control gain are performed using the magnitude of the difference between the target rotation speed and the actual rotation speed with respect to the operation amount of the trigger switch 12, and the respective characteristic values including the average current and the current ripple. The above description has been made with reference to an example in which both adjustments are performed. However, the present invention is not limited to this.
For example, the configuration may be such that only one of rewriting of the speed table and adjustment of the control gain is performed based on each of the characteristic values.

(B)
In the above embodiment, based on three characteristic values of the magnitude of the difference between the target rotation speed and the actual rotation speed with respect to the operation amount of the trigger switch 12 acquired in the first operation, the average current, and the current ripple, The description has been given by taking an example of optimizing the control condition for the second operation to be performed. However, the present invention is not limited to this.

For example, control for optimizing the control condition for the second operation may be performed based on at least one of the difference between the target rotation speed and the actual rotation speed, the average current, and the current ripple. .
Alternatively, the control condition of the motor of the power tool may be optimized based on another characteristic value other than the three characteristic values described in the above embodiment.

(C)
In the above embodiment, the operation from the time when the trigger switch 12 is turned on by the operation of the trigger switch 12 to the time when the trigger switch 12 is turned off is regarded as the first operation. The work from the time when the work becomes OFF to the OFF state is defined as a second work, and optimization of the motor control conditions for the second work is repeatedly performed for each work based on a difference or the like acquired in the first work. The example has been described. However, the present invention is not limited to this.

For example, several operations may be set as the first operation, and the control condition for the second operation performed thereafter may be optimized based on the average value of the differences acquired in the several operations.
Alternatively, the optimization of the control conditions for the second work is not only performed after the completion of the first work, but also the first work is set every predetermined number of times, and the control conditions for the second work are optimized thereafter. May be implemented.

(D)
In the above-described embodiment, an example in which the inclination of the target rotation speed table is adjusted and the control gain is adjusted is described as the optimization control for the second operation. However, the present invention is not limited to this.
For example, the optimization control for the second operation is not limited to the control described above, and the control condition for the second operation may be optimized by another control.

(E)
In the above embodiment, an example using fuzzy inference when performing the optimization control for the second operation has been described. However, the present invention is not limited to this.
In the method of controlling a motor of a power tool according to the present invention, the use of fuzzy inference is not essential, and may be implemented by other methods.

(F)
In the above-described embodiment, an example in which the material such as the hardness and the homogeneity of the processed material is estimated using the characteristic values (speed deviation, average current, current ripple) acquired in the previous operation (first operation). Explained. However, the present invention is not limited to this.
For example, the material of the processing material estimated in the present invention may be a material other than hardness and homogeneity.

(G)
In the above embodiment, an example in which a brushless motor is used as the motor 16 has been described. However, the present invention is not limited to this.
For example, a DC motor other than the brushless motor that is driven to rotate in accordance with the operation amount of the trigger switch may be used.

(H)
In the above-described embodiment, an example has been described in which the present invention is implemented as the power tool 10 and the control method of the power tool 10. However, the present invention is not limited to this.
For example, the present invention may be realized as a control program that causes a computer to execute the control method of the power tool 10 described in the above embodiment.

The control program only needs to be stored in the storage unit 26 shown in FIG. 1, and is read by the CPU, whereby the computer can execute the control method described above.

The power tool of the present invention has an effect that an optimum motor control condition can be set by a simple operation, and thus can be widely applied to power tools used in various works.

10 Power tool 11 Battery (power supply)
12 Trigger switch (speed setting section)
13 Gate circuit (switching circuit)
14 FET array (switching circuit)
14a Switching element 15 Current detection resistor 16 Motor (DC motor)
16a Coil 16b Hall IC
16c Rotor 17 Magnetic pole position detection circuit 18 Reset switch 20 Control unit 21 Table reference unit 22 Operation amount calculation unit 23 Current speed calculation unit (detection unit)
24 Correction coefficient calculation unit 25 Current calculation unit (current measurement unit)
26 storage unit 27 PWM signal generation unit

Claims (23)

A DC motor,
A speed setting unit that sets the rotation speed of the DC motor according to an operation amount;
A switching circuit having a plurality of switching elements and supplying power to the DC motor,
The switching circuit is controlled to rotate the DC motor based on the rotation speed set by the speed setting unit, and the first circuit is controlled based on the characteristic value of the DC motor acquired in the first operation. A control unit that sets a control condition of the DC motor in a second operation of the same type as the first operation, which is to be performed following the operation;
A power tool equipped with. A detection unit that detects an actual rotation speed of the DC motor, further includes:
The characteristic value includes a difference between the target rotation speed of the DC motor with respect to the operation amount of the speed setting unit and the actual rotation speed detected by the detection unit.
The power tool according to claim 1. The control unit, when performing the second operation, rewrites a table indicating a relationship between the operation amount of the speed setting unit and the target rotation speed according to the magnitude of the difference,
The power tool according to claim 2. The control unit, when performing the second operation, adjusts a control gain output to the switching circuit according to the magnitude of the difference,
The power tool according to claim 2. A current measuring unit that measures a current flowing through a circuit connected to the DC motor, further comprising:
The power tool according to any one of claims 1 to 4. The characteristic value includes at least one of an average current and a current ripple calculated based on the current value measured by the current measuring unit.
The power tool according to claim 5. The control unit, when performing the second operation, according to at least one of the average current and the current ripple, a table indicating a target rotation speed of the DC motor corresponding to the operation amount of the speed setting unit. rewrite,
The power tool according to claim 6. The control unit adjusts a control gain output to the switching circuit according to at least one of the average current and the current ripple when performing the second operation.
The power tool according to claim 6. The control unit estimates a material of a processing material based on the characteristic value of the DC motor obtained in the first operation.
The power tool according to any one of claims 1 to 8. The material of the processing material includes hardness, homogeneity,
The power tool according to claim 9. A storage unit that stores the characteristic value related to the DC motor,
The power tool according to any one of claims 1 to 10. A reset switch for returning a control condition of the DC motor to an initial condition, further comprising:
The power tool according to any one of claims 1 to 11. The control unit sets a control condition of the DC motor in the second operation based on the characteristic value acquired in the first operation using fuzzy inference.
The power tool according to any one of claims 1 to 12. It is a control method of the electric tool as described in any one of Claims 1 to 13, Comprising:
In the first operation, rotating the DC motor under the control condition set in advance;
In the first operation, obtaining the characteristic value of the DC motor;
Adjusting the control condition of the DC motor in the second operation of the same type as the first operation, which is performed subsequent to the first operation, based on the characteristic value acquired in the first operation;
Rotating the DC motor according to the adjusted control condition in the second operation;
The control method of the electric tool provided with. The characteristic value includes a difference between a target rotation speed of the DC motor with respect to the operation amount of the speed setting unit and an actual rotation speed of the DC motor.
A method for controlling a power tool according to claim 14. In the second operation, a table indicating a relationship between the operation amount of the speed setting unit and the target rotation speed is rewritten according to the magnitude of the difference.
A method for controlling a power tool according to claim 15. Adjusting the control gain output to the switching circuit according to the magnitude of the difference in the second operation;
A method for controlling a power tool according to claim 15. The characteristic value includes at least one of an average current and a current ripple calculated based on a current value measured by a current measurement unit that measures a current flowing in a circuit connected to the DC motor.
A method for controlling a power tool according to any one of claims 14 to 17. In the second operation, a table indicating a target rotation speed of the DC motor corresponding to an operation amount of the speed setting unit is rewritten according to at least one of the average current and the current ripple,
A method for controlling a power tool according to claim 18. In the second operation, a control gain output to the switching circuit is adjusted according to at least one of the average current and the current ripple,
The control method for a power tool according to claim 18. Further comprising estimating a material of a processing material based on the characteristic value of the DC motor obtained in the first operation,
The control method for a power tool according to any one of claims 14 to 20. The material of the processing material includes hardness, homogeneity,
A method for controlling a power tool according to claim 21. It is a control program of the electric tool according to any one of claims 1 to 13,
In the first operation, rotating the DC motor under the control condition set in advance;
In the first operation, obtaining the characteristic value of the DC motor;
Adjusting the control condition of the DC motor in the second operation of the same type as the first operation, which is performed subsequent to the first operation, based on the characteristic value acquired in the first operation;
Rotating the DC motor according to the adjusted control condition in the second operation;
A control program for causing a computer to execute a power tool control method including

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