TW202508785A - Device and method for limiting the movement of a robot, device and method for setting movement parameters, and computer program - Google Patents

Abstract

When all operations of a robot outside an allowable operation range are prohibited, work efficiency may decrease. Meanwhile, when overload is applied to the robot while operating outside the allowable operation range, damage may occur to the robot. This device for limiting the operation of a robot comprises: an information acquisition unit that acquires information relating to a load applied to a robot; a range determination unit that determines, on the basis of the information acquired by the information acquisition unit, whether or not the robot is outside the allowable operation range determined in accordance with the load; and an operation limiting unit that, when the range determination unit has determined that the robot is outside the allowable operation range, permits an operation of the robot toward the allowable operation range while prohibiting an operation of the robot departing from the allowable operation range.

Description

Device and method for limiting the movement of a robot, device and method for setting movement parameters, and computer program

The present disclosure relates to a device and method for limiting the movement of a robot, a device and method for setting movement parameters, and a computer program.

It is known that there is a device for determining the permissible range of motion of a robot (e.g., Patent Document 1). [Prior Art Document] [Patent Document]

[Patent Document 1] International Publication No. 2021/187378

[The problem the invention is trying to solve]

If all actions of the robot outside the permitted action range are prohibited, the work efficiency may be reduced. On the other hand, if an overload is applied to the robot in action outside the permitted action range, the robot may be damaged. [Technical means to solve the problem]

In one aspect of the present disclosure, a device for limiting the movement of a robot comprises: an information acquisition unit, which acquires information about a load applied to the robot; a range determination unit, which determines whether the robot is outside a permissible movement range determined according to the load based on the information acquired by the information acquisition unit; and a movement restriction unit, which allows the robot to move within the permissible movement range when the range determination unit determines that the robot is outside the permissible movement range, and prohibits the robot from moving away from the permissible movement range.

The device for setting the action parameters of a robot for performing a designated action comprises: an information acquisition unit that acquires information about a load applied to the robot; a parameter setting unit that sets the action parameters for the robot to perform the action based on the information acquired by the information acquisition unit; and a range determination unit that determines whether the robot is outside the permissible action range determined based on the load indicated by the information acquired by the information acquisition unit. When the range determination unit determines that the robot is outside the permissible action range, the parameter setting unit retains the setting of the action parameters.

The method of limiting the movement of a robot is that a processor obtains information about the load applied to the robot, and based on the obtained information, determines whether the robot is outside the allowable movement range determined by the load. When it is determined that the robot is outside the allowable movement range, the robot is allowed to move toward the allowable movement range. On the other hand, the robot is prohibited from moving away from the allowable movement range.

The method for setting the motion parameters of a robot that performs a specified action is that a processor obtains information about a load applied to the robot, sets the motion parameters based on the obtained information so that the robot performs the action, determines whether the robot holding the workpiece is outside the allowable motion range determined by the load indicated by the obtained information, and retains the setting of the motion parameters when it is determined that the robot is outside the allowable motion range.

The following is a detailed description of the embodiments of the present disclosure based on the drawings. In addition, in the various embodiments described below, the same elements are marked with the same symbols, and repeated descriptions are omitted. First, referring to Figures 1 and 2, a robot system 10 of an embodiment is described. The robot system 10 has a robot 12, a control device 14, and a teaching device 16.

The robot 12 is a vertical multi-joint robot and performs a specified action. In this embodiment, as a specified action, the robot 12 performs a transport action CO of transporting a workpiece W placed at a specified initial position Pi to a specified transport position Pc. Specifically, the robot 12 has a robot base 18, a rotating body 20, a lower arm 22, an upper arm 24, a wrist 26, and a manipulator 28. The robot base 18 is fixed to the floor of the work unit or an unmanned transport vehicle (AGV: Automated Guided Vehicle).

The rotating body 20 is provided on the robot base 18 so as to be rotatable around a lead straight axis. The base end of the lower arm 22 is provided on the rotating body 20 so as to be rotatable around a horizontal axis. The base end of the upper arm 24 is provided on the front end of the lower arm 22 so as to be rotatable. The wrist 26 has: a wrist base 26a provided on the front end of the upper arm 24 so as to be rotatable around two axes orthogonal to each other; and a wrist flange 26b provided on the wrist base 26a so as to be rotatable around a wrist axis A1.

The robot 28 is detachably mounted on the wrist flange 24b. As one example, the robot 28 has a plurality of claws that can be opened and closed, and the workpiece W is clamped between the claws to fix the workpiece W. As another example, the robot 28 has a suction part (vacuum suction plate, etc.) that generates negative pressure between the robot 28 and the workpiece W, and the workpiece W is suctioned and fixed by the suction part.

Servo motors 30 (FIG. 2) are provided on each component of the robot 12 (robot base 18, rotating main body 20, lower arm 22, upper arm 24 and wrist 26). The servo motors 30 rotate and drive the drive shafts of the robot 12 according to the instructions from the control device 14, thereby causing the movable components of the robot 12 such as the rotating main body 20, lower arm 22, upper arm 24, wrist base 26a and wrist flange 26b (i.e., robot hand 28) to rotate around the drive shafts respectively. In this way, the robot 12 can move the workpiece W held by the robot hand 28 to any position.

Furthermore, the robot 12 is provided with a force sensor 32 ( FIG. 2 ) for detecting an external force F applied to the robot 12. The force sensor 32 is, for example, a 6-axis force sensor provided on any component of the robot 12 (e.g., the robot base 18 or the wrist 26 ), or a torque sensor provided on each of the servo motors 30 , and supplies detection data Df of the detected external force F to the control device 14.

A robot coordinate system C1 and a tool coordinate system C2 are set on the robot 12. The robot coordinate system C1 is a fixed coordinate system used to control the motion of each movable component of the robot 12. In the present embodiment, the robot coordinate system C1 is set on the robot base 18 in such a way that its origin is arranged at the center of the robot base 18 and its z-axis is parallel to (specifically, consistent with) the rotation axis of the rotating main body 20.

On the other hand, the tool coordinate system C2 is a moving coordinate system that specifies the position P and posture O of the manipulator 28 in the robot coordinate system C1. In the present embodiment, the tool coordinate system C2 is set on the manipulator 28 in such a way that its origin (the so-called TCP) is arranged at the workpiece holding position of the manipulator 28, and its z-axis is parallel to (specifically, consistent with) the wrist axis A1. In addition, the origin of the tool coordinate system C2 may also be arranged at the center of the wrist flange 26b.

When the robot 28 is moved in the robot coordinate system C1, the control device 14 sets the tool coordinate system C2 for the robot coordinate system C1, and arranges the robot 28 at the position P and posture O represented by the set tool coordinate system C2, thereby generating instructions for each servo motor 30. In this way, the control device 14 can position the robot 28 (and the workpiece W held) at an arbitrary position P and posture O in the robot coordinate system C1 by driving each servo motor 30.

The control device 14 is a computer having a processor 34, a memory 36, an I/O (Input/Output) interface 38, a display device 40, and an input device 42. The processor 34 has a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit), etc., and is communicatively connected to the memory 36, the I/O interface 38, the display device 40, and the input device 42 via a bus 43, communicates with these components, and performs calculation processing for realizing various functions described below.

The memory 36 has RAM (Random Access Memory) or ROM (Read Only Memory), etc., and stores various data temporarily or permanently. The memory 36 can also be a non-temporary recording medium that can be read by a computer, such as a semiconductor memory, a magnetic recording medium, or an optical recording medium. The I/O interface 38 has, for example, an Ethernet (registered trademark) port, a USB (Universal Serial Bus) port, an optical fiber connector, or an HDMI (High Definition Multimedia Interface) (registered trademark) terminal, and communicates data with an external device by wire or wirelessly under the command from the processor 34.

The display device 40 has a liquid crystal display or an organic EL (Electro Luminescence) display, etc., and can visually display various data under the command from the processor 34. The input device 42 has a push button, a switch, a keyboard, a mouse or a touch panel, etc., and accepts the input of data from the operator. In addition, the display device 40 and the input device 42 can be integrated into the outer casing of the control device 14, or can be a computer (PC (Personal Computer) etc.) separated from the outer casing of the control device 14 and connected to the I/O interface 38.

The teaching device 16 teaches the robot 12 the actions. Specifically, the teaching device 16 is a computer having a processor 44, a memory 46, an I/O interface 48, a display device 50, and an input device 52. In addition, the teaching device 16 can also be a teaching pendant, or any type of computer such as a notebook or tablet PC.

The processor 44 is communicatively connected to the memory 46, the I/O interface 48, the display device 50, and the input device 52 via the bus 53. In addition, since the configurations of the processor 44, the memory 46, the I/O interface 48, the display device 50, and the input device 52 are the same as those of the processor 34, the memory 36, the I/O interface 38, the display device 40, and the input device 42 described above, repeated descriptions thereof will be omitted.

In this embodiment, the processor 34 of the control device 14 is configured to execute the micro-motion mode MD1 and the direct teaching mode MD2 as the operation mode MD of the robot 12. In the micro-motion mode MD1, the processor 34 moves the movable components of the robot 12 according to the micro-motion command CMj input by the operator through the input device 42 of the teaching device 16.

On the other hand, in the direct teaching mode MD2, the processor 34 receives the operating force Fh applied by the operator to any movable component of the robot 12 (for example, the wrist 26 or the manipulator 28) as a direct teaching instruction CMd, so that the movable component to which the operating force Fh is applied moves in the direction of the operating force Fh.

The processor 34 can calculate the magnitude and direction of the operator's operating force Fh based on the detection data Df of the force sensor 32, and specify the movable component to which the operating force Fh is applied. In this way, in this embodiment, the processor 34 moves the robot 12 according to the operator's micro-movement command CMj or direct teaching command CMd (operating force Fh).

Next, referring to FIG3 , the functions of the robot system 10 are described. Next, the functions of the robot system 10 when the operator teaches the above-mentioned transport action CO to the robot 12 are described. The operator gives the above-mentioned micro-movement instruction CMj or direct teaching instruction CMd to the processor 34 so that the robot 28 holds the workpiece W placed at the initial position Pi. When the processor 34 holds the workpiece W with the robot 28, the process of FIG3 is started.

In step S1, the processor 34 obtains information IF1 of the load L applied to the robot 12 from the workpiece W. The load L applied to the robot 12 includes, for example, the weight WG and inertia IN of the workpiece W, the moment MO applied from the workpiece W to the wrist 26 (specifically, the wrist flange 26b), and the load torque TQ applied to each servo motor 30. The information IF1 of the load L includes, for example, the value of the load L (i.e., the weight WG, the inertia IN, the moment MO or the load torque TQ, etc.) and the coordinates Qg of the center of gravity of the load L. The coordinates Qg of the center of gravity can also be expressed as the coordinates of the tool coordinate system C2 set on the robot 28 holding the workpiece W.

For example, the type (identification code or model number, etc.) of the workpiece W carried by the robot 12 is associated with the information IF1 of the load L (i.e., the value of the load L, the coordinates Qg of the center of gravity, etc.) pre-stored in the memory 36 (or 46). The processor 34 can also identify the type of the workpiece W held by the robot 12 at the start point of FIG. 3 and obtain the information IF1 corresponding to the workpiece W by reading it from the memory 36.

In this case, the operator may also operate the input device 42 (or 52) to input the type of workpiece W. Alternatively, the processor 34 may also obtain the type of workpiece W from the teaching program. As another example, the operator may operate the input device 42 (or 52) to manually input the information IF1 of the load L, and the processor 34 may obtain the information IF1 through the input device 42.

As another example, the processor 34 can measure the value of the load L (weight WG, inertia IN, moment MO or load torque TQ) based on the detection data Df of the force sensor 32 as information IF1. In this way, the processor 34 obtains the information IF1 of the load L by reading from the memory 36, input from the operator or actual measurement. Therefore, the processor 34 functions as the information acquisition unit 62 (Figure 2) that obtains the information IF1 of the load L.

In step S2, the processor 34 determines the permissible motion range AR based on the load L indicated by the information IF1 obtained in step S1. Here, the permissible motion range AR is determined for the robot 12 based on the load L in order to avoid overloading the robot 12. An example of the permissible motion range AR is shown in FIG4.

In this embodiment, the allowable range of motion AR is an allowable position range that determines the allowable range of position P of the robot 12 (specifically, the manipulator 28 or the tool coordinate system C2). In the example shown in FIG. 4 , as the allowable range of motion AR, an allowable range of motion AR1, an allowable range of motion AR2 that is larger than the allowable range of motion AR1, and an allowable range of motion AR3 that is larger than the allowable range of motion AR2 are determined. The maximum allowable range of motion AR3 can also be defined by the maximum reachable distance that the robot 12 can make the manipulator 28 reach.

For example, the permissible motion range AR1 is applied to a range where the distance d from the robot base 18 (i.e., the origin of the robot coordinate system C1) is d≦d1 (e.g., d1=100 [mm]), and the load L is L≧L1 (e.g., load L=weight WG≧L1=20 [kg]). On the other hand, the permissible motion range AR2 is applied to a range where the distance d is d≦d2 (e.g., d2=300 [mm]), and the load L is L2≦L＜L1 (e.g., L2=10 [kg]≦L=WG≦L1=20 [kg]).

Furthermore, the permissible motion range AR3 is applied to the range where the distance d is d≦d3 (for example, d3=500 [mm]), and the load L is 0≦L＜L2. In addition, FIG. 4 shows an example of determining three permissible motion ranges AR1, AR2, and AR3, but two permissible motion ranges AR may be determined, or four or more permissible motion ranges AR may be determined.

As an example, as shown in Fig. 4, a database 100 is created in advance to store a plurality of allowable motion ranges AR1, AR2, and AR3 having different ranges in association with the load L. An example of the database 100 is shown in Fig. 5. The database 100 is created by an operator and stored in advance in the memory 36 (or 46).

In step S2, the processor 34 selects the permissible motion range AR corresponding to the load L shown in the information IF1 obtained in step S1 from the plurality of permissible motion ranges AR1, AR2 and AR3 stored in the database 100. For example, in the information IF1 obtained in step S1, the load L = weight WG = 15 [kg], and L2 = 10 [kg], and L1 = 20 [kg]. In this case, the processor 34 applies the load L = 15 [kg] to the database 100 and selects the permissible motion range AR2 for the load L such that L2 = 10 [kg] ≤ L < L1 = 20 [kg]. In this way, the processor 34 selects the permissible motion range AR1, AR2 or AR3 corresponding to the load L.

As another example, the processor 34 performs a specified operation using the load L indicated by the information IF1 obtained in step S1, and obtains the allowable range of motion AR corresponding to the load L through the operation. For example, the distance d defining the allowable range of motion AR can be expressed as a function of the load L of d=f(L). Each term of the function f(L) can be determined by the operator. For example, in the information IF1 obtained in step S1, the load L=weight WG=15[kg].

In this case, the processor 34 substitutes the load L = weight WG = 15 [kg] into the function f (L). Assuming that when d = f (15 [kg]) = 300 [mm], the processor 34 obtains the allowable range of motion AR2 for d ≧ 300 [mm]. In this way, the processor 34 obtains the allowable range of motion AR corresponding to the load L by performing the specified operation (the operation of the expression d = f (L)) using the load L.

As described above, in this embodiment, when the processor 34 obtains the information IF1 in step S1, it determines the permissible motion range AR (e.g., the permissible motion range AR1, AR2, or AR3) by selecting from the database 100 according to the load L indicated by the information IF1 or performing a specified operation. Therefore, the processor 34 functions as a range setting unit 64 (FIG. 2) that determines the permissible motion range AR according to the load L. The permissible motion range AR determined in step S2 is set as the motion parameter OP for the robot 12 to perform the transport motion CO.

In step S3, the processor 34 determines whether the robot 12 holding the workpiece W is outside the permissible motion range AR based on the information IF1 obtained in step S1. For example, the processor 34 obtains the coordinate Q1 of the origin of the tool coordinate system C2 at that time in the robot coordinate system C1 as the current position _Pn of the robot 12.

Alternatively, the processor 34 may also obtain the coordinates Q2 of the center of gravity position of the load L at that time in the robot coordinate system C1 as the current position _Pn of the robot 12. The coordinates Q2 of the center of gravity position in the robot coordinate system C1 can be obtained from the coordinates Q1 of the tool coordinate system C2 in the robot coordinate system C1 and the coordinates Qg of the center of gravity position in the tool coordinate system C2 included in the information IF1 obtained in step S1.

Furthermore, the processor 34 determines whether the acquired current position _Pn is outside the permissible motion range AR (e.g., the permissible motion range AR1, AR2, or AR3) set in step S2 based on the information IF1 (i.e., the load L). When the current position _Pn is outside the permissible motion range AR, the processor 34 determines YES and proceeds to step S4. On the other hand, when the current position _Pn is inside the permissible motion range AR, the processor 34 determines NO and proceeds to step S5. Thus, in the present embodiment, the processor 34 functions as the range determination unit 66 (FIG. 2) that determines whether the robot 12 is outside the permissible motion range AR based on the information IF1.

In step S4, the processor 34 executes the out-of-range program. Referring to FIG. 6 , the step S4 is described. In step S11, the processor 34 determines whether the instruction CM for causing the robot 12 to perform the transport action CO has been accepted. For example, in order for the robot 12 to perform the transport action CO, the operator gives the processor 34 the above-mentioned micro-motion instruction CMj or the direct teaching instruction CMd as the instruction CM. When the processor 34 has accepted the instruction CM (CMt or CMd), it determines that it is yes and proceeds to step S12. On the other hand, when it is determined that it is no, it proceeds to step S18.

In step S12, the processor 34 determines whether the robot 12 is moving inside the permissible motion range AR set in step S2 when the robot 12 performs the transport motion CO according to the command CM received in the most recent step S11. For example, the processor 34 obtains the target position Pn ₊₁ for moving the robot 28 (i.e., the workpiece W) according to the command CM.

For example, the processor 34 obtains the coordinates Q3 of the origin of the tool coordinate system C2 set in the robot coordinate system C1 as the target position Pn ₊₁ according to the command CM. Alternatively, the processor 34 obtains the coordinates Q4 of the robot coordinate system C1 of the center of gravity position of the workpiece W moved by the robot 12 as the target position Pn ₊₁ according to the command CM. The coordinates Q4 of the center of gravity position can be obtained from the coordinates Q3 of the origin of the tool coordinate system C2 and the coordinates Qg of the center of gravity position included in the information IF1 obtained in step S1.

Furthermore, the processor 34 obtains the distance δ n _{+1 from the obtained target position P n +1} to the boundary B of the allowable motion range AR set in step S2, and the distance δ _n from the current position P _n of the robot 12 at that time point to the boundary B. Furthermore, when the condition δ _n+1 <δ _n is satisfied, the processor 34 determines that the robot 12 is heading to the inside of the allowable motion range AR (i.e., yes).

As another example, the processor 34 obtains the moving direction (or moving vector) DR for moving the robot 28 (i.e., the workpiece W) according to the command CM. For example, the processor 34 obtains the direction from the above-mentioned current position _Pn toward the target position Pn ₊₁ as the moving direction DR. Furthermore, when the moving direction (movement vector DR) intersects the boundary B of the allowable motion range AR set in step S2, the processor 34 determines that the robot 12 is facing the inside of the allowable motion range AR (i.e., yes).

If the processor 34 determines that it is yes, it proceeds to step S13, and if it determines that it is no, it proceeds to step S14. If the processor 34 determines that it is no in step S12, it proceeds to step S14. If the processor 34 determines that it is no in step S12, it means that when the robot 12 is operated according to the command CM received in step S11, the robot 28 (i.e., the workpiece W) moves in a direction away from the permissible operating range AR.

In step S13, the processor 34 causes the robot 12 to perform the transport action CO. Specifically, the processor 34 causes the robot 12 to move according to the command CM (CMt or CMd) received in the most recent step S11, so as to move the workpiece W held by the robot arm 28. At this time, the robot 12 moves the workpiece W in a direction toward the inside of the permissible motion range AR set in step S2.

On the other hand, if the determination in step S12 is negative, in step S14, the processor 34 generates an alarm AL1. For example, the processor 34 generates an image or sound alarm AL1 of "The robot is overloaded. It cannot perform any action other than the action within the allowable action range." And, the processor 34 displays the generated alarm AL1 on the display device 40 (or 50), or outputs it through a speaker (not shown). And, the processor 34 returns to step S11. In this way, in the present embodiment, the processor 34 functions as an alarm generating unit 68 (FIG. 2) that generates the alarm AL1.

As described above, when the processor 34 determines that it is yes in step S12, it allows the transport action CO to be executed in step S13. On the other hand, even if the processor 34 continues to accept the instruction C in step S11, during the period when it determines that it is no in step S12, the loop of steps S11, S12 and S14 is repeated, thereby prohibiting the execution of the transport action CO of step S13. Therefore, the processor 34 functions as the action restriction unit 70 (Figure 2), that is, it allows the robot 12 to perform the transport action CO within the allowable action range AR, and on the other hand, prohibits the robot 12 from performing the transport action CO away from the allowable action range AR.

In step S15, the processor 34 determines whether the robot 12 is in contact with the surrounding environmental object E (operator, structure such as a column, or other workpiece, etc.) based on the detection data Df of the force sensor 32. Specifically, the processor 34 calculates the size and direction of the contact force Fc applied to the robot 12 by the environmental object E based on the detection data Df.

Furthermore, the processor 34 determines that the calculated contact force Fc exceeds the specified threshold value _Fth (F> _Fth ). The processor 34 proceeds to step S16 when the determination is yes, and proceeds to step S17 when the determination is no. Thus, in this embodiment, the processor 34 functions as a contact determination unit 72 (FIG. 2) that determines whether the robot 12 is in contact with the environmental object E based on the detection data Df.

In step S16, the processor 34 causes the robot 12 to perform the retreat action RO. Specifically, the processor 34 stops the transport action CO of the robot 12 being performed in step S13. For example, a brake mechanism (not shown) is provided to brake the rotation of each servo motor 30, and the processor 34 brakes the servo motor 30 by activating the brake mechanism, thereby stopping the transport action CO of the robot 12 in an emergency.

Next, the processor 34 causes the robot 12 to execute the evacuation action RO of moving the manipulator 28 in the opposite direction DR' of the moving direction DR in the transport action CO of step S13. The processor 34 can obtain the vector from the target position Pn ₊₁ of the transport action CO of step S13 to the current position Pn before the robot 12 is arranged at the target position Pn _{+1 as} the direction DR'.

Here, the processor 34 functions as the action limiting unit 70 in the above steps S12 and S13, and prohibits the robot 12 from performing the transport action CO far from the permissible action range AR. However, in the step S16, the processor 34 functions as the action limiting unit 70, and allows the retreat action RO even if the direction DR' of the retreat action RO is toward the direction outside the permissible action range AR (i.e., the direction far from the permissible action range AR) in order to surely eliminate the contact between the robot 12 and the environmental object E. As a result, the robot 12 performs the retreat action RO of moving the manipulator 28 in the direction DR'.

In addition, the processor 34 may also move the robot 12 (robot 28) in the direction opposite to the direction of the contact force Fc obtained in the nearest step S15 in the retraction action RO. In addition, the processor 34 may move the robot 12 (robot 28) a predetermined distance in the retraction action RO, or may monitor the magnitude of the contact force Fc during the execution of the retraction action RO and continue the retraction action RO until the magnitude becomes less than the threshold value _Fth (F≦ _Fth ). In addition, the processor 34 may also move the robot 12 in the retraction action RO at a speed V2 (<V1) lower than the speed V1 of the robot 12 in the transport action CO of step S13.

Furthermore, when executing the above-mentioned direct teaching mode MD2, the processor 34 may also make the robot 12 move in the direction of the operating force Fh applied to the robot 12 by the operator in the retreat action RO until a specified time (e.g., 10 seconds) has passed. In this case, even if the direction of the operating force Fh is outside the allowable motion range AR, the processor 34 allows the robot 12 to move outside the allowable motion range AR (i.e., in the direction of the operating force Fh).

In step S17, the processor 34 functions as the range determination unit 66, and determines whether the robot 12 is outside the permissible motion range AR, similar to the above-mentioned step S3. If the processor 34 determines that it is yes, the process proceeds to step S18. On the other hand, if the processor 34 determines that it is no (i.e., the robot 12 is within the permissible motion range AR), the process proceeds to step S5 in FIG. 3 .

In step S18, the processor 34 determines whether the transport action CO is completed. For example, the processor 34 determines that it is yes when the workpiece W has been transported to the transport position Pc by the robot 12. Alternatively, the processor 34 may determine that it is yes when receiving the action completion instruction from the operator. When the processor 34 determines that it is yes, the process of FIG. 6 is terminated, and accordingly, the process of FIG. 3 is terminated. On the other hand, when the processor 34 determines that it is no, it returns to step S11.

Referring again to FIG. 3, if the determination result in step S3 is negative, in step S5, the processor 34 executes the in-range program. The step S5 is described with reference to FIG. 7. In step S21, the processor 34 determines whether the command CM is accepted, similarly to the above-mentioned step S11. If the determination result is positive, the process proceeds to step S22. On the other hand, if the determination result is negative, the process proceeds to step S28.

In step S22, the processor 34 causes the robot 12 to perform the transport operation CO, similar to the above-mentioned step S13. In the transport operation CO, the robot 12 moves the workpiece W not only within the permissible motion range AR set in step S2, but also in a direction outside the permissible motion range AR.

In step S23, the processor 34 functions as the contact determination unit 72, and similarly to the above-mentioned step S15, determines based on the detection data Df whether the robot 12 is in contact with the environmental object E. If the processor 34 determines that it is yes, the process proceeds to step S24, and if it determines that it is no, the process proceeds to step S25.

In step S24, the processor 34 causes the robot 12 to execute the evacuation action RO, similar to the above-mentioned step S16. In the evacuation action RO, the processor 34 may cause the robot 12 to move in the opposite direction DR' to the moving direction DR of the transport action CO in step S22, or in the opposite direction to the direction of the contact force Fc obtained in the most recent step S23. Furthermore, even if the robot 12 moves outside the permissible action range AR during the execution of the evacuation action RO, the processor 34 functions as the action limiting unit 70 and permits the evacuation action RO.

In step S25, the processor 34 determines whether the robot 12 is outside the permissible motion range AR at that time point, similarly to the above-mentioned step S3. When the processor 34 determines that it is yes, it proceeds to step S4 in FIG. 3 . On the other hand, when it determines that it is no, it proceeds to step S26. In step S26, the processor 34 determines whether the robot 12 performing the transport action CO has approached the boundary B of the permissible motion range AR. Specifically, the processor 34 obtains the current position _Pn (e.g., coordinates Q1 or Q2) of the robot 12 at that time point. At that time point, since the robot 12 performs the transport action CO within the permissible motion range AR, the current position _Pn becomes within the permissible motion range AR.

Next, the processor 34 obtains the distance δ _n from the obtained current position P _n to the boundary B of the allowable motion range AR set in step S2. When the obtained distance δ _n becomes less than the specified threshold δ _th (δ _n ≦δ _th ), the processor 34 determines that it is yes and proceeds to step S27. On the other hand, when δ _n >δ _th , the processor 34 determines that it is no and proceeds to step S28.

In step S27, the processor 34 functions as the alarm generating unit 68 and generates an alarm AL2. For example, the processor 34 generates an image or sound alarm AL2 of "approaching the boundary of the allowable range of motion." Furthermore, the processor 34 displays the generated alarm AL2 on the display 40 (or 50) or outputs it through a speaker (not shown).

Alternatively, a light-emitting device (rotating lamp, LED (Light Emitting Diode) lamp, etc.) may be provided in the control device 14, the teaching device 16 or the robot 12, and the processor 34 generates an alarm AL2 to make the light-emitting device emit light. Alternatively, a vibrator (or a tactile generating device) may be provided in the teaching device 16 or the robot 12, and the processor 34 generates an alarm AL2 to make the vibrator vibrate.

Thus, in this embodiment, the processor 34 functions as the alarm generating unit 68, and generates an alarm AL2 when the robot 12 executing the transport action CO within the allowable action range AR approaches the boundary B of the allowable action range AR. In step S28, the processor 34 determines whether the transport action CO is completed, similarly to the above-mentioned step S18. When the processor 34 determines that it is yes, the process of FIG. 7 is terminated, thereby terminating the process of FIG. 3. On the other hand, when the processor 34 determines that it is no, it returns to step S21.

As described above, in the present embodiment, the processor 34 functions as the information acquisition unit 62, the range setting unit 64, the range determination unit 66, the alarm generation unit 68, the action restriction unit 70, and the contact determination unit 72 to restrict the action (specifically, the transport action CO) performed by the robot 12. Therefore, the information acquisition unit 62, the range setting unit 64, the range determination unit 66, the alarm generation unit 68, the action restriction unit 70, and the contact determination unit 72 constitute the device 60 for restricting the action of the robot 12 (FIG. 2).

In the device 60, the information acquisition unit 62 acquires information IF1 (value of the load L, coordinates Qg, etc.) of the load L (weight WG, inertia IN, moment MO, load torque TQ, etc.) applied to the robot 12 (step S1). Furthermore, the range determination unit 66 determines whether the robot 12 holding the workpiece W is outside the allowable motion range AR (for example, the allowable motion range AR1, AR2, or AR3) determined according to the load L based on the information IF1 acquired by the information acquisition unit 62 (steps S3, S17, S25).

Furthermore, when the action restriction unit 70 determines through the range determination unit 66 that the robot 12 is outside the permitted action range AR (i.e., in step S3, S17 or S25), the robot 12 is allowed to move toward the action CO within the permitted action range AR (step S13). On the other hand, the robot 12 is prohibited from moving away from the action CO within the permitted action range AR (loop of steps S11, S12 and S14).

Here, for example, when teaching the robot 12 a transport action CO, the robot 12 may be caused to hold a workpiece W with an excess load L outside the permissible action range AR. In this case, if any action of the robot 12 is prohibited, the teaching operation has to be interrupted, and the operation efficiency is reduced. On the other hand, even if the robot 12 is outside the permissible action range AR, as long as the action is directed toward the permissible action range AR, the possibility of ensuring the safety of the robot 12 is high.

According to the device 60, even when the robot 12 is outside the permissible range of motion AR, the safety of the robot 12 can be ensured and the work efficiency can be improved by allowing the action CO toward the permissible range of motion AR. On the other hand, when the robot 12 is outside the permissible range of motion AR, if it moves in a direction away from the permissible range of motion AR, the possibility of damage to the components of the robot 12 due to overload increases. According to the device 60, by prohibiting the action CO away from the permissible range of motion AR, damage to the robot 12 can be prevented.

Furthermore, in the device 60, when the information acquisition unit 62 acquires the information IF1, the range setting unit 64 determines the permissible motion range AR (AR1, AR2 or AR3) according to the load L indicated by the information IF1 (step S2). According to this configuration, since the permissible motion range AR corresponding to the load L applied to the robot 12 can be appropriately determined, it is possible to avoid setting the permissible motion range AR too large or, conversely, too narrow. Thereby, the safety of the robot 12 can be more effectively ensured, and the operation efficiency can be more effectively improved.

In one example of the device 60, a plurality of mutually different permissible motion ranges AR1, AR2, and AR3 (FIG. 4) are associated with the load L and pre-stored in the memory 36 (or 46), and the range setting unit 64 selects the permissible motion range AR1, AR2, or AR3 corresponding to the load L indicated by the information IF1 from the plurality of permissible motion ranges AR1, AR2, and AR3 (step S2). According to this configuration, the permissible motion range AR1, AR2, or AR3 corresponding to the load L can be determined quickly and with a simple algorithm.

In another example of the device 60, the range setting unit 64 performs a specified operation (for example, an operation of the expression d=f(L)) using the load L indicated by the information IF1 to obtain the allowable motion range AR corresponding to the load L. According to this configuration, the allowable motion range AR most suitable for the load L can be quickly determined by appropriately designing the operation expression: d=f(L).

Furthermore, in the device 60, the alarm generating unit 68 generates an alarm AL1 (step S14) when the action limiting unit 70 prohibits the action CO. According to this configuration, the operator can intuitively recognize that the action CO cannot be performed in a direction away from the permissible action range AR. On the other hand, the alarm generating unit 68 generates an alarm AL2 (step S27) when the robot 12 performing the action CO (step S22) within the permissible action range AR approaches the boundary B of the permissible action range AR. According to this configuration, since the operator can intuitively recognize that the robot 12 is approaching the boundary B, the robot 12 can be prevented from moving outside the permissible action range AR.

Furthermore, in the device 60, the contact determination unit 72 determines whether the robot 12 is in contact with the environmental object E based on the detection data Df of the force sensor 32 that detects the external force F applied to the robot 12 (steps S15, S23). Furthermore, when the contact determination unit 72 determines that the robot 12 is in contact with the environmental object E (yes in step S15 or S23), the action restriction unit 70 allows the robot 12 to perform an evacuation action RO outside the permitted action range AR in order to eliminate the contact. According to this configuration, even if the robot 12 is in contact with the environmental object (such as the operator) during the execution of the action CO, damage to the robot 12 or the environmental object E can be avoided.

In addition, in the above-mentioned embodiment, the operator has been described to teach the robot 12 the transport action CO. However, this is not limited to this, and the processor 34 can also execute the process of Figure 3 when making the robot 12 automatically execute the transport action CO according to the action program PG1 for the transport action CO.

In this case, the processor 34 automatically receives the action command CMo as the command CM in the command code specified by the program PG1 in the above step S11 or S21. In addition, in the above embodiment, the robot 12 can also continuously perform the transport action CO of transporting multiple types of workpieces _W1 , _W2 , ..., _Wm with different loads L. In this case, the processor 34 can execute the flow of Figure 3 each time a new workpiece _Wk is held.

In the above embodiment, the processor 34 (range setting unit 64) has been described as determining the permissible motion range AR according to the load L in step S2. However, the invention is not limited thereto, and the permissible motion range AR may be predetermined. For example, as described above, a transport operation CO of transporting a plurality of workpieces W ₁ , W ₂ , ..., W _m having different loads L is performed.

In this case, the load _Lk of the workpiece _Wk among the loads L of the plurality of workpieces _W1 , _W2 , ..., _Wm is set to be the largest. In this case, the permissible motion range AR (e.g., the permissible motion range AR1 in FIG. 4 ) corresponding to the maximum load _Lk can also be predetermined by the motion parameter OP. That is, in this case, step S2 can be omitted from the flow of FIG. 3 , and the range setting unit 64 can be omitted from the device 60 .

Furthermore, when the robot 12 is not allowed to hold the actual workpiece W during teaching, and the general movement of the transport operation CO is to be determined, the operator does not need to pay attention to the allowable movement range AR corresponding to the maximum load _Lk every time by predetermining the allowable movement range AR corresponding to the workpiece W. As a result, when the robot 12 is allowed to perform the transport operation CO after teaching, it can be avoided that the robot 12 cannot move due to overload.

Furthermore, step S14 may be omitted from the flow of FIG. 6, and step S27 may be omitted from the flow of FIG. 7. That is, in this case, the alarm generating unit 68 may be omitted from the device 60. Furthermore, steps S15 and S16 may be omitted from the flow of FIG. 6, and steps S23 and S24 may be omitted from the flow of FIG. 7. That is, in this case, the contact determining unit 72 may be omitted from the device 60.

In addition, the processor 34 may also execute the process shown in FIG. 3 according to the computer program PG2 pre-stored in the memory 36 (or 46). Furthermore, the functions of the device 60 (i.e., the information acquisition unit 62, the range setting unit 64, the range determination unit 66, the alarm generation unit 68, the action restriction unit 70, and the contact determination unit 72) executed by the processor 34 may also be a functional module implemented by the computer program PG2.

Next, referring to FIG8 and FIG9, other functions of the robot system 10 are described. The processor 34 of the control device 14 shown in FIG8 executes the process shown in FIG9. The processor 34 starts the process shown in FIG9 when the robot arm 28 holds the workpiece W, similar to the process of FIG3. In step S31, the processor 34 functions as the information acquisition unit 62, and acquires the information IF1 of the load L, similar to the above-mentioned step S1.

In step S32, the processor 34 obtains information IF2 of the permissible motion range AR. For example, the processor 34 determines the permissible motion range AR based on the load L indicated by the information IF1 obtained in step S1 in the same manner as step S2 in FIG. 3. For example, a plurality of permissible motion ranges AR1, AR2, and AR3 are pre-stored in the database 100, and the processor 34 selects the permissible motion range AR corresponding to the load L from the plurality of permissible motion ranges AR1, AR2, and AR3.

Alternatively, the processor 34 may also perform a specified operation using the load L (e.g., an operation of the expression d=f(L)) to obtain the allowable motion range AR corresponding to the load L. The processor 34 obtains information IF2 of the allowable motion range AR determined based on the load L (e.g., the distance d described above, or the coordinates of the boundary B of the allowable motion range AR in the robot coordinate system C1). As another example, the specified allowable motion range AR may be determined in advance and stored in the memory 36 (or 46), and the processor 34 obtains the information IF2 of the allowable motion range AR by reading it from the memory 36.

In step S33, the processor 34 functions as the range determination unit 66 to determine whether the robot 12 holding the workpiece W is outside the permissible motion range AR. Specifically, based on the information IF2 obtained in step S32, the processor 34 determines whether the current position _Pn (coordinates Q1 or Q2, etc.) of the robot 12 at that time is outside the permissible motion range AR indicated by the information IF2. If the processor 34 determines that it is yes, the process proceeds to step S34. On the other hand, if the processor 34 determines that it is no, the process proceeds to step S35.

In step S34, the processor 34 functions as the alarm generating unit 68 and generates an alarm AL3. For example, the processor 34 generates an image or sound alarm AL3 of "The robot is overloaded and cannot start to move. Please set the load-related action parameters again." In addition, the processor 34 displays the generated alarm AL3 on the display device 40 (or 50), or outputs it through a speaker (not shown). In addition, the processor 34 ends the process of Figure 9.

On the other hand, if the determination in step S33 is negative, in step S35, the processor 34 sets the action parameter OP based on the information IF1 obtained in step S31. The action parameter OP is a parameter that specifies the action conditions for the robot 12 to perform the transport action CO, and includes, for example, information IF1 of the load L, information IF2 of the permissible action area AR determined based on the load L, and conditions such as the speed V and acceleration α of the robot 12.

Here, in this embodiment, if at least one of the action parameters OP (for example, the allowable action area AR determined by the load L, and conditions such as the speed V and the acceleration α) is not formally set (for example, if it is not registered in the parameter database DB), the processor 34 cannot execute the transport action CO.

In step S35, the processor 34 formally sets the information IF1 of the load L obtained in step S31 and the information IF2 of the permissible motion range AR obtained in step S32 together with the conditions such as the velocity V and the acceleration α as the motion parameter OP (for example, registers it in the parameter database DB). As a result, the processor 34 becomes in a state where the transport motion CO can be executed according to the motion parameter OP. In this way, in the present embodiment, the processor 34 functions as a parameter setting unit 82 (FIG. 8) that sets the motion parameter OP based on the information IF1.

In step S36, the processor 34 executes the in-range program. Referring to FIG. 10 , the step S36 is explained. In addition, in the process shown in FIG. 10 , the same step numbers are used for the same programs as those in the process of FIG. 7 , and repeated explanations are omitted. When it is determined as yes in step S21, in step S41, the processor 34 functions as the range determination unit 66, and when the robot 12 is caused to perform the transport action CO according to the instruction CM received in the most recent step S21, it is determined whether the robot 12 has moved outside the allowable action range AR set as the action parameter OP in step S35.

Specifically, the processor 34 obtains the target position P _n+1 of the instruction CM in the same manner as in the above-mentioned step S12. Furthermore, the processor 34 determines whether the obtained target position P _n+1 is outside the permissible motion range AR. When the target position P _n+1 is outside the permissible motion range AR, the processor 34 determines that it is yes and proceeds to step S42. On the other hand, when the target position P _n+1 is within the permissible motion range AR, the processor 34 determines that it is no and proceeds to step S22 to cause the robot 12 to perform the transport motion CO according to the instruction CM.

If the judgment in step S41 is yes, in step S42, the processor 34 functions as the alarm generating unit 68 and generates an alarm AL4. For example, the processor 34 generates an image or sound alarm signal AL4 that "the robot is outside the permitted range of motion, so it cannot move in that direction." In addition, the processor 34 displays the generated alarm AL4 on the display device 40 (or 50), or outputs it through a speaker (not shown). In addition, the processor 34 returns to step S21.

Thus, when the processor 34 determines in step S41 that it is no (i.e., the robot 12 moves within the permitted range of motion AR), the transport action CO of step S22 is permitted. On the other hand, even if the processor 34 continues to accept the instruction C in step S21, the loop of steps S21, S41, and S42 is repeated during the period when the processor 34 determines in step S41 that it is yes, thereby prohibiting the execution of the transport action CO of step S22.

That is, the processor 34 functions as the action restriction unit 70, that is, the transport action CO that allows the robot 12 to move within the permitted action range AR, and on the other hand, the transport action CO that prohibits the robot 12 from moving outside the permitted action range AR. After step S22, the processor 34 functions as the contact determination unit 72 and the alarm generation unit 68, and executes the above-mentioned steps S23, S24, S26, S27 and S28 in sequence.

As described above, in the flow of Fig. 9, when the processor 34 determines that it is yes in step S33, the setting of the action parameter OP in step S35 is not performed. In this case, the processor 34 receives input of information IF1 of a new load L from the operator in step S31, and then, when it determines that it is no in step S33, it executes step S35 to set the action parameter OP.

Instead, the processor 34 moves to step S37 (out-of-range procedure) in FIG. 11 described later, and then executes the setting of the action parameter OP when receiving the command C. In this way, in the present embodiment, the processor 34 functions as the parameter setting unit 82, and when the determination in step S33 is yes, the setting of the action parameter OP is retained (in other words, temporarily prohibited) until the specified condition is met (for example, the information IF2 of the load L is obtained again, or the process moves to the out-of-range procedure).

In addition, when the processor 34 determines in step S33 that the setting of the action parameter OP is retained, the flag FG indicating the subject can also be effectively set. During the period when the flag FG is valid, the processor 34 cannot perform the setting of the action parameter OP. Furthermore, when the processor 34 determines in step S33 that the setting is negative, the flag FG can also be set to invalid.

As described above, in the present embodiment, the processor 34 functions as the information acquisition unit 62, the range determination unit 66, the alarm generation unit 68, the motion restriction unit 70, the contact determination unit 72, and the parameter setting unit 82 to set the motion parameter OP of the robot 12 that performs the designated motion (specifically, the transport motion CO). Therefore, the information acquisition unit 62, the range determination unit 66, the alarm generation unit 68, the motion restriction unit 70, the contact determination unit 72, and the parameter setting unit 82 constitute a device 80 for setting the motion parameter OP ( FIG. 8 ).

In the device 80, the information acquisition unit 62 acquires the information IF1 of the load L (step S31), and the range determination unit 66 determines whether the robot 12 holding the workpiece W is outside the permissible motion range AR determined based on the load L indicated by the information IF1 (step S33). The parameter setting unit 82 sets the motion parameter OP based on the information IF1 acquired by the information acquisition unit 62 so that the robot 12 performs the motion CO (step S35). Here, when the range determination unit 66 determines that the robot 12 is outside the permissible motion range AR (yes in step S33), the parameter setting unit 82 retains the setting of the motion parameter OP.

Previously, the action parameter OP was automatically set based on the information IF1 of the acquired load L. In contrast, in the device 80, even if the information acquisition unit 62 acquires the information IF1 in step S31, if it is determined to be yes in step S33, the action parameter OP is not set, thereby prohibiting the action CO. According to this configuration, the robot 12 outside the permissible action range AR can be surely prohibited from executing the action CO in an overload state. As a result, the safety of the robot 12 can be surely ensured.

Furthermore, in the device 80, when the range determination unit 66 determines that the robot 12 is within the permissible motion range AR (No in step S33), the parameter setting unit 82 sets the permissible motion range AR as the motion parameter OP (step S35). Furthermore, the motion restriction unit 70 permits the robot 12 to perform a transport motion CO within the permissible motion range AR (step S22 in FIG. 10 ), and prohibits the robot 12 from performing a transport motion CO outside the permissible motion range AR (the loop of steps S21, S41, and S42 in FIG. 10 ). According to this configuration, since the robot 12 can be prevented from moving outside the permissible motion range AR and becoming overloaded, the safety of the robot 12 can be effectively ensured.

In the device 80, the alarm generating unit 68 generates an alarm AL3 (step S34) when the range determining unit 66 determines that the robot 12 is outside the permissible motion range AR (yes in step S33). According to this configuration, the operator can intuitively recognize that the setting of the motion parameter and the purpose of the motion CO cannot be performed due to overload.

In the above embodiment, the information IF1 of the load L and the information IF2 of the permissible motion area AR are set as the motion parameter OP. However, the present invention is not limited thereto, and the motion parameter OP may include only the conditions such as the velocity V and the acceleration α as the motion parameter OP without including the information IF1 and IF2.

Furthermore, steps S41 and S42 may be omitted from the flow of FIG. 10. That is, in this case, the action limiting unit 70 may be omitted from the device 80. Furthermore, step S34 may be omitted from the flow of FIG. 9, and steps S42 and S47 may be omitted from the flow of FIG. 10. That is, in this case, the alarm generating unit 68 may be omitted from the device 80. Furthermore, steps S23 and S24 may be omitted from the flow of FIG. 10. That is, in this case, the contact determining unit 72 may be omitted from the device 80.

In addition, the processor 34 may also execute the process shown in FIG. 9 according to the computer program PG3 pre-stored in the memory 36 (or 46). Furthermore, the functions of the device 80 (i.e., the information acquisition unit 62, the range determination unit 66, the alarm generation unit 68, the action restriction unit 70, the contact determination unit 72 and the parameter setting unit 82) executed by the processor 34 may also be a functional module implemented by the computer program PG3.

Next, another example of the operation flow executed by the robot system 10 shown in FIG8 will be described with reference to FIG11. The flow shown in FIG11 is different from the flow shown in FIG9 in the following procedures. That is, in the flow shown in FIG11, after step S34, the processor 34 moves to the out-of-range procedure of step S37.

This step S37 is shown in FIG12. In addition, when moving to step S37, the processor 34 may set the flag FG to be invalid, and set the information IF1 of the load L obtained in step S31 in FIG11 and the information IF2 of the allowable motion range AR obtained in step S32 together with the conditions such as the speed V and the acceleration α as the motion parameter OP.

In step S37 shown in FIG12, the processor 34 executes steps S11 to S18 in the same manner as step S6 in FIG6, but if the determination in step S17 is negative, the process proceeds to step S36 in FIG11. In addition, in the process of FIG11, step S4 shown in FIG6 may be executed to replace step S36, and step S5 shown in FIG7 may be executed to replace step S37.

Next, referring to Fig. 13, the other functions of the robot system 10 are described. In this embodiment, the processor 34 functions as the above-mentioned device 60, and the device 60 further has an image generation unit 74. Next, referring to Fig. 14, the function of the image generation unit 74 is described. The process shown in Fig. 14 is different from the process of Fig. 3 in step S6.

Specifically, after step S2, in step S6, the processor 34 generates image data 110 that displays the allowable motion range AR determined in step S2. An example of the image data 110 is shown in FIG15. In the example shown in FIG15, the image data 110 includes an action parameter display area 112 and a model display area 114. In the action parameter display area 112, the action parameter OP set at that time is displayed.

In the example shown in FIG. 15 , the information IF1 of the load L (specifically, the weight WG, the inertia IN, and the center of gravity position (coordinate Qg)) is displayed in the motion parameter display area 112 as the motion parameter OP. In addition, as the information IF1 of the load L, the moment MO and the load torque TQ may also be displayed. Furthermore, the conditions such as the speed V and the acceleration α may also be displayed in the motion parameter display area 112 as the motion parameter OP.

In the model display area 114, a robot model 12M (for example, a 3DCAD (3 Dimensions Computer-Aided Design) model) that models the robot 12 and the allowable range of motion AR determined in step S2 are displayed in three dimensions. In addition, FIG. 15 shows an example of displaying the allowable range of motion AR2. In this way, in the present embodiment, the processor 34 functions as an image generation unit 74 that generates image data 110 that displays the allowable range of motion AR.

The processor 34 displays the generated image data 110 on the display device 40 (or 50). In addition, the processor 34 can also obtain the current position _Pn of the robot 12 at the start time of step S6, and display the robot model 12M configured at the current position _Pn in the model display area 114. According to this structure, the operator can easily confirm the position relationship between the allowable motion range AR2 determined in step S2 and the robot 12 (specifically, the robot hand 28) relative to the boundary B. In addition, after step S32 in FIG. 9, step S6 can be executed to generate and display the image data 110 of the allowable motion range AR determined in step S32. That is, in this case, the device 80 in FIG. 8 further has an image generation unit 74.

In the above-mentioned embodiment, the allowable range of motion AR is an allowable range of position that determines the allowable range of position P of the robot 12. However, the allowable range of motion AR is not limited to this, and the allowable range of motion AR may also be an allowable range of posture that determines the allowable range of posture O of the robot 12 (specifically, the robot arm 28 or the tool coordinate system C2) instead of the allowable range of position (or in addition to the allowable range of position).

The allowable motion range AR as the allowable posture range is described with reference to FIGS. 16 to 18. In the examples shown in FIGS. 16 to 18, the allowable motion range AR (allowable posture range) is defined as the angle θ between the wrist axis A1 of the robot 12 and the vertical direction J. Specifically, the allowable motion range AR includes an allowable motion range AR11 (FIG. 16), an allowable motion range AR12 (FIG. 17) larger than the allowable motion range AR11, and an allowable motion range AR13 (FIG. 18) larger than the allowable motion range AR12.

The allowable motion range AR11 is applied to a range where the angle θ is θ≦θ1 (for example, θ1=30°) and the load L is L≧L1 (for example, L1=20[kg]). On the other hand, the allowable motion range AR12 is applied to a range where the angle θ is θ≦θ2 (for example, θ2=60°＞θ1) and the load L is L2≦L＜L1 (for example, L2=10[kg]). Furthermore, the allowable motion range AR13 is applied to a range where the angle θ is θ≦θ3 (for example, θ3=90°＞θ2) and the load L is 0≦L＜L2. In addition, as the allowable posture range, an arbitrary number of allowable motion ranges AR may be determined.

The processor 34 may also determine the allowable posture range AR11, AR12 or AR13 as the allowable posture range based on the information IF1 of the load L in the above-mentioned step S2 or S32. In addition, the processor 34 may also determine the allowable position ranges AR1, AR2 and AR3 and the allowable posture ranges AR11, AR12 or AR13 as the allowable posture range AR.

In this case, the processor 34 may also determine the allowable position range AR1, AR2 or AR3, and the allowable posture range AR11, AR12 or AR13 as the allowable posture range AR in the above-mentioned step S2 or S32, and execute the above-mentioned steps S3, S12, S17, S25, S33 or S41 for each of the determined allowable position range AR1, AR2 or AR3, and the allowable posture range AR11, AR12 or AR13.

In addition, the processor 34 may also have the functions of the device 60 (information acquisition unit 62, range setting unit 64, range determination unit 66, alarm generating unit 68, motion restriction unit 70, contact determination unit 72, image generating unit 74) and the functions of the device 80 (information acquisition unit 62, range determination unit 66, alarm generating unit 68, motion restriction unit 70, contact determination unit 72 and parameter setting unit 82).

Furthermore, in the above-mentioned embodiment, the case where the functions of the device 60 (information acquisition unit 62, range setting unit 64, range determination unit 66, alarm generation unit 68, motion restriction unit 70, contact determination unit 72, image generation unit 74) are installed in the control device 14 has been described. However, at least one of the functions of the device 60 may also be installed in another computer (for example, the teaching device 16). In this case, the processor (processor 44) of the other computer (teaching device 16) functions as the device 60. Similarly, at least one of the functions of the device 80 (information acquisition unit 62, range determination unit 66, alarm generation unit 68, motion restriction unit 70, contact determination unit 72, parameter setting unit 82) may also be installed in another computer (for example, the teaching device 16).

In addition, in the above-mentioned embodiment, the case where the actual robot 12 executes the process of FIG. 3, FIG. 9, FIG. 11 and FIG. 14 has been described. However, it is not limited to this. The processor 34 can also function as the device 60 or 80 to make the robot model 12M arranged in the virtual space simulate and execute the process of FIG. 3, FIG. 9, FIG. 11 or FIG. 14 (i.e., simulation). In addition, the robot 12 is not limited to a vertical multi-joint robot, and can also be a horizontal multi-joint robot, a parallel rod robot, or any other type of robot that can transport the workpiece W. In addition, the robot 12 can also be set in any place such as the wall or ceiling of the work unit.

In addition, in the above-mentioned embodiment, the robot 12 has been described as performing the transporting action CO as the designated action. However, the robot 12 is not limited to this, and can also perform the welding action WO of welding the workpiece W using a plurality of types of welding guns GN (not shown) of different weights as the designated action. In this case, the robot 12 sequentially attaches and detaches the various types of welding guns GN to the wrist flange 26b in a series of welding actions WO. In this case, the load L applied to the robot 12 from the welding gun GN changes according to the progress of the welding action WO.

When the processor 34 (or 44) performs such a welding action WO, it can also execute the same process as that of FIG. 3, FIG. 9, FIG. 11 or FIG. 14. In this case, for example, when the processor 34 (or 44) replaces the welding gun GN mounted on the wrist flange 26b at the designated tool replacement location, it can start the process of FIG. 3, FIG. 9, FIG. 11 or FIG. 14 and execute the process based on the load L applied to the robot 12 from the welding gun GN. In this way, the concept of the present disclosure is not limited to the transport action CO, but can also be applied to any other action such as applying a load L to the robot 12.

The present disclosure has been described in detail above, but the present disclosure is not limited to the above-mentioned embodiments. These embodiments may be added, replaced, changed, partially deleted, etc., without departing from the scope of the present disclosure, or without departing from the scope of the present disclosure derived from the contents recorded in the scope of the patent application and its equivalents. Moreover, these embodiments may also be implemented in combination. For example, in the above-mentioned embodiments, the sequence of each action or the sequence of each processing is shown as an example, and is not limited to this. Moreover, the same applies to the description of the above-mentioned embodiments using numerical values or formulas.

This disclosure discloses the following aspects. (Aspect 1) A device 60 that limits the action of a robot 12 (e.g., a transport action CO) comprises: an information acquisition unit 62 that acquires information IF1 of a load L applied to the robot 12; a range determination unit 66 that determines whether the robot 12 is outside the permissible action range AR (AR1, AR2, AR3, AR11, AR12, AR13) determined according to the load L based on the information IF1 acquired by the information acquisition unit 62; and an action restriction unit 70 that allows the robot 12 to move toward the permissible action range AR when the range determination unit 66 determines that the robot 12 is outside the permissible action range AR, and prohibits the robot 12 from moving away from the permissible action range AR. (Aspect 2) The device 60 described in aspect 1 further includes a range setting unit 64, which determines the permissible motion range AR based on the load L indicated by the information IF1 when the information acquisition unit 62 acquires the information IF1. (Aspect 3) The device 60 described in aspect 2, wherein a plurality of mutually different permissible motion ranges AR1, AR2, AR3, AR11, AR12, AR13 are associated with the load L and pre-stored, and the range setting unit 64 selects the permissible motion range AR1, AR2 or AR3, or AR11, AR12 or AR13 corresponding to the load L indicated by the information IF1 from the plurality of permissible motion ranges AR1, AR2, AR3, AR11, AR12, AR13. (Aspect 4) The device 60 described in aspect 2, wherein the range setting unit 64 performs a specified operation using the load L indicated by the information IF1 to obtain the allowable range of motion AR corresponding to the load L. (Aspect 5) The device 60 described in any one of aspects 2 to 4 further includes an image generating unit 74 that generates image data 110 that displays the allowable range of motion AR determined by the range setting unit 64. (Aspect 6) The device 60 described in any one of aspects 1 to 5 further includes an alarm generating unit 68 that generates an alarm AL1 when the action limiting unit 70 prohibits an action that deviates from the allowable range of motion AR. (Sample 7) A device 80 for setting the action parameter OP of a robot 12 that performs a specified action (e.g., a transport action CO), comprising: an information acquisition unit 62 that acquires information IF1 of a load L applied to the robot 12; a parameter setting unit 82 that sets the action parameter OP based on the information IF1 acquired by the information acquisition unit 62 so that the robot 12 performs the action; and a range determination unit 66 that determines whether the robot 12 is outside the permissible action range AR determined based on the load L indicated by the information IF1 acquired by the information acquisition unit 62; and the parameter setting unit 82 retains the setting of the action parameter OP when the range determination unit 66 determines that the robot 12 is outside the permissible action range AR. (Aspect 8) The device 80 described in aspect 7, wherein the action parameter OP includes at least one of the load L and the permissible action range AR. (Aspect 9) The device 80 described in aspect 8, wherein when the range determination unit 66 determines that the robot 12 is within the permissible action range AR, the parameter setting unit 82 sets the permissible action range AR as the action parameter OP, and the device 80 further includes an action restriction unit 70 that allows the robot 12 to move within the permissible action range AR, and prohibits the robot 12 from moving outside the permissible action range AR. (Aspect 10) The device 80 described in any one of aspects 7 to 9 further includes an alarm generating unit 68, which generates an alarm AL3 when the range determining unit 66 determines that the robot 12 is outside the permissible action range AR. (Aspect 11) The device 60, 80 described in any one of aspects 1 to 10, wherein the permissible action range AR has at least one of the permissible position ranges AR1, AR2 and AR3 that determine the permissible range of the position P of the robot 12, and the permissible posture ranges AR11, AR12 and AR13 that determine the permissible range of the posture O of the robot 12. (Aspect 12) The device 60, 80 described in aspect 11, wherein the allowable posture ranges AR11, AR12, and AR13 are defined as the angle θ between the wrist axis A1 of the robot 12 and the vertical direction J. (Aspect 13) The device 60, 80 described in any one of aspects 1 to 12 further includes an alarm generating unit 68, which generates an alarm AL2 when the robot 12 performing an action within the allowable action range AR approaches a boundary B of the allowable action range AR. (Aspect 14) The device 60, 80 described in aspect 1 or 9 further comprises a contact determination unit 72, which determines whether the robot 12 is in contact with the environmental object E based on the detection data Df of the force sensor 32 that detects the external force F applied to the robot 12; the action restriction unit 70 allows the robot 12 to perform an evacuation action RO outside the permissible action range AR in order to eliminate the contact when the contact determination unit 72 determines that the robot 12 is in contact with the environmental object E. (Sample 15) A method for limiting the action of the robot 12 (e.g., the transport action CO) is that the processor 34 obtains information IF1 of the load L applied to the robot 12, and based on the obtained information IF1, determines whether the robot 12 is outside the allowable action range AR determined according to the load L. If it is determined that the robot 12 is outside the allowable action range AR, the robot 12 is allowed to move within the allowable action range AR, and on the other hand, the robot is prohibited from moving away from the allowable action range AR. (Example 16) A method for setting an action parameter OP of a robot 12 that performs a specified action, wherein the processor 34 obtains information IF1 of a load L applied to the robot 12 from a workpiece W, sets the action parameter OP based on the obtained information IF1 so that the robot 12 performs the action, determines whether the robot 12 is outside the allowable action range AR determined based on the load L indicated by the obtained information IF1, and retains the setting of the action parameter OP when it is determined that the robot 12 is outside the allowable action range AR. (Example 17) A computer program PG2, PG3, which causes the processor 34 to execute the method described in Example 15 or 16.

10: Robot system 12: Robot 12M: Robot model 14: Control device 16: Teaching device 18: Robot base 20: Rotating body 22: Lower arm 24: Upper arm 26: Wrist 26a: Wrist base 26b: Wrist flange 28: Robot hand 30: Servo motor 32: Force sensor 34: Processor 36: Memory 38: I/O interface 40: Display device 42: Input device 43: Bus 44: Processor 46: Memory 48: I/O interface 50: Display device 52: Input device 53: Bus 60: Device 62: Information acquisition unit 64: Range setting unit 66: Range determination unit 68: Alarm generation unit 70: Action restriction unit 72: Contact determination unit 74: Image generation unit 80: Device 82: Parameter setting unit 100: Database 110: Image data 112: Action parameter display area 114: Model display area A1: Wrist axis AR1: Allowable action range AR2: Allowable action range AR3: Allowable action range AR11: Allowable action range (allowable posture range) AR12: Allowable action range (allowable posture range) AR13: Allowable action range (allowable posture range) C1: robot coordinate system C2: tool coordinate system d: distance d1: distance d2: distance d3: distance J: lead vertical direction L: load L1: load L2: load S1~S5: steps S11~S18: steps S21~S28: steps S31~S37: steps S41,S42: steps W: workpiece θ1: angle θ2: angle θ3: angle

FIG. 1 is a schematic diagram of a robot system of an embodiment. FIG. 2 is a block diagram of the robot system shown in FIG. 1. FIG. 3 is a flow chart showing the functions of the robot system shown in FIG. 2. FIG. 4 shows an example of an allowable range of motion. FIG. 5 shows an example of a database of allowable range of motion. FIG. 6 is a flow chart showing an example of the process of step S4 in FIG. 3. FIG. 7 is a flow chart showing an example of the process of step S5 in FIG. 3. FIG. 8 is a block diagram showing other functions of the robot system shown in FIG. 1. FIG. 9 is a flow chart showing the functions of the robot system shown in FIG. 8. FIG. 10 is a flow chart showing an example of the process of step S36 in FIG. 9. FIG. 11 is a flowchart showing other functions of the robot system shown in FIG. 8 FIG. 12 is a flowchart showing an example of the process of step S37 in FIG. 11 FIG. 13 is a block diagram showing other functions of the robot system shown in FIG. 2 FIG. 14 is a flowchart showing the functions of the robot system shown in FIG. 13 FIG. 15 shows an example of image data representing the allowable action range AR. FIG. 16 shows an example of the allowable posture range. FIG. 17 shows an example of the allowable posture range. FIG. 18 shows an example of the allowable posture range.

10: Robotic system

12:Robots

14: Control device

16: Teaching device

30:Servo motor

32: Force sensor

34: Processor

36: Memory

38:I/O interface

40: Display device

42: Input device

43: Bus

44:Processor

46: Memory

48:I/O interface

50: Display device

52: Input device

53: Bus

60: Device

62: Information Acquisition Department

64: Range setting department

66: Range determination unit

68: Alarm generation department

70: Movement restriction unit

72: Contact determination unit

Claims (17)

A device for limiting the movement of a robot comprises: an information acquisition unit for acquiring information about a load applied to the robot; a range determination unit for determining whether the robot is outside a permissible movement range determined according to the load based on the information acquired by the information acquisition unit; and a movement restriction unit for allowing the robot to move toward the permissible movement range when the range determination unit determines that the robot is outside the permissible movement range, and prohibiting the robot from moving away from the permissible movement range. The device of claim 1 further comprises a range setting unit, which determines the allowable range of movement based on the load indicated by the information when the information acquisition unit acquires the information. As in the device of claim 2, a plurality of mutually different allowable motion ranges are associated with the load and stored in advance, and the range setting unit selects the allowable motion range corresponding to the load indicated by the information from the plurality of allowable motion ranges. As in the device of claim 2, wherein the range setting unit obtains the allowable motion range corresponding to the load by performing a specified operation using the load indicated by the information. The device of claim 2 further comprises an image generating unit for generating image data for displaying the above-mentioned allowable movement range determined by the above-mentioned range setting unit. The device of claim 1 further comprises an alarm generating unit for generating an alarm when the action limiting unit prohibits the remote action. A device for setting the action parameters of a robot that performs a specified action, comprising: an information acquisition unit that acquires information about a load applied to the robot; a parameter setting unit that sets the action parameters based on the information acquired by the information acquisition unit so that the robot performs the action; and a range determination unit that determines whether the robot is outside the allowable action range determined based on the load indicated by the information acquired by the information acquisition unit; and the parameter setting unit retains the setting of the action parameters when the range determination unit determines that the robot is outside the allowable action range. A device as claimed in claim 7, wherein the above-mentioned action parameters include at least one of the above-mentioned load and the above-mentioned allowable action range. The device of claim 8, wherein when the range determination unit determines that the robot is within the allowable range of motion, the parameter setting unit sets the allowable range of motion as the motion parameter, and the device further comprises a motion restriction unit that allows the robot to move within the allowable range of motion and prohibits the robot from moving outside the allowable range of motion. The device of claim 7 further comprises an alarm generating unit for generating an alarm when the range determination unit determines that the robot is outside the allowable range of motion. A device as claimed in claim 1 or 7, wherein the allowable range of motion has at least one of an allowable position range that determines the allowable range of the position of the robot and an allowable posture range that determines the allowable range of the posture of the robot. As in the device of claim 11, the above-mentioned allowable posture range is defined as the angle formed by the wrist axis of the above-mentioned robot and the vertical direction. The device of claim 1 or 7 further comprises an alarm generating unit for generating an alarm when the robot performing the above-mentioned action within the above-mentioned allowable action range approaches the boundary of the allowable action range. The device of claim 1 or 9 further comprises a contact determination unit, which determines whether the robot is in contact with an environmental object based on detection data of a force sensor that detects an external force applied to the robot; When the contact determination unit determines that the robot is in contact with the environmental object, the action restriction unit allows the robot to retreat outside the allowable action range in order to eliminate the contact. A method for limiting the movement of a robot is to have a processor obtain information about a load applied to the robot from the workpiece, and to determine whether the robot is outside a permissible range of movement determined based on the load based on the obtained information. If the robot is determined to be outside the permissible range of movement, the robot is allowed to move toward the permissible range of movement, and on the other hand, the robot is prohibited from moving away from the permissible range of movement. A method for setting the motion parameters of a robot that performs a specified motion, wherein a processor obtains information about a load applied to the robot, sets the motion parameters based on the obtained information so that the robot performs the motion, determines whether the robot holding the workpiece is outside the allowable motion range determined based on the load indicated by the obtained information, and retains the setting of the motion parameters when it is determined that the robot is outside the allowable motion range. A computer program that causes the above-mentioned processor to execute the method as claimed in claim 15 or 16.