JP2018103345A - Robot system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress a decrease in production efficiency while ensuring safety when an obstacle such as a person approaches a robot main body. A distance sensor 4 is attached to the surface of a robot body 2 and can detect a distance L to an obstacle such as a person located substantially in the normal direction with respect to the surface. The collision prevention controller 8 sends a command to the robot controller 5 to operate the robot body 2 so as to avoid a collision with a person or the like according to the detection result of the distance L. The collision prevention controller 8 stores a plurality of threshold values T1, T2, T3 (T1> T2> T3) for determining the degree of approach of a human or the like to the robot body 2. In the case of L ≦ T1, the command for operating at a low speed, in the case of L ≦ T2, the command for continuing the work while retracting, and in the case of L ≦ T3, the command for stopping is the collision prevention controller. It is sent from 8 to the robot controller 5, and the robot body 2 operates based on the command. [Selection diagram] Fig. 1

Description

  The present invention relates to a robot system capable of cooperating with a person.

  In recent years, attention has been paid to the technology of a robot system capable of cooperating with a person. Specifically, for example, development of a robot apparatus that performs assembling work alongside a person on a production line is underway. Patent document 1 discloses this kind of robot apparatus. The robot apparatus of Patent Document 1 includes a manipulator as a robot, an intrusion detection unit that monitors an intrusion of an obstacle such as a person near the manipulator movable region, and a control unit that controls the operation of the manipulator. It has become.

JP 2010-208002 A

  In the robot apparatus of Patent Document 1, when an intrusion of an obstacle such as a person into a warning area that covers the movable area of the manipulator and is wider than the movable area is detected, the control means is controlled. The operation of the manipulator is decelerated. Also, when an obstacle such as a person enters the movable area of the manipulator and the distance between the manipulator and the obstacle is less than a predetermined distance, the operation of the manipulator is stopped by controlling the control means. Let's make it happen.

  As a result, when a person enters a warning area wider than the movable area of the manipulator, the operation speed of the manipulator is reduced, and the person is moved to a place where the distance between the person and the manipulator is less than or equal to a predetermined distance in the warning area. When approaching the manipulator, the manipulator is stopped to reduce the threat to the person of the robot apparatus.

  However, in the configuration of Patent Document 1, the manipulator is frequently decelerated and stopped because the operating speed of the manipulator is decelerated or stopped even when the threat to the human being of the robot apparatus is not particularly problematic. There was a problem that the production efficiency decreased.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a robot system capable of suppressing a decrease in production efficiency while ensuring safety when an obstacle such as a person approaches the robot body. It is to provide.

  The problems to be solved by the present invention are as described above. Next, means for solving the problems and the effects thereof will be described.

  According to an aspect of the present invention, a robot system having the following configuration is provided. That is, the robot system includes a robot body, a control unit, at least one detection unit, and a collision prevention control unit. The control unit controls the operation of the robot main body to perform work. The detection unit is attached to a surface of the robot body or a tool attached to the robot body, and can detect a distance to an obstacle positioned in a direction substantially normal to the surface. The collision prevention control unit sends a command for operating the robot body to prevent a collision with the obstacle according to the detection result of the detection unit. The collision prevention control unit stores a plurality of threshold values for determining the degree of approach of the obstacle to the robot body or the tool. The collision prevention control unit, when the detection result of the detection unit is less than or equal to a first threshold value, causes the robot body to operate at a lower speed than when the detection result of the detection unit exceeds the first threshold value. Send a low speed operation command. The collision prevention control unit is configured to continue the operation while retracting the robot body in a direction away from the obstacle when the detection result of the detection unit is equal to or smaller than a second threshold value that is smaller than the first threshold value. Either a retreat operation command that is a command or a stop command that is a command for stopping the operation of the robot body is sent. The collision prevention control unit sends either the retraction operation command or the stop command when the detection result of the detection unit is equal to or smaller than a third threshold value smaller than the second threshold value.

  Thereby, the fall of production efficiency can be suppressed, ensuring the safety when the person etc. as an obstruction approach the robot main body and the tool.

  ADVANTAGE OF THE INVENTION According to this invention, the fall of production efficiency can be suppressed, ensuring the safety when obstructions, such as a person, approached the robot main body.

1 is a schematic diagram showing an overall configuration of a robot system according to an embodiment of the present invention. The block diagram which shows the main structures of a collision prevention controller. The figure explaining the determination content based on the some threshold value memorize | stored in a collision prevention controller. The block diagram which shows the main structures of a robot controller. The figure which illustrates the description of the operation | movement program memorize | stored in a robot controller. The figure which illustrates typically the spatial judgment performed with a robot controller in order to acquire feasible evacuation operation | movement. The flowchart which shows the process performed with a collision prevention controller. The flowchart which shows the process performed with a robot controller regarding a collision prevention command.

  Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram showing an overall configuration of a robot system 1 according to an embodiment of the present invention.

  A robot system 1 shown in FIG. 1 is a robot system according to the present embodiment, and controls the robot body 2 so that it can cooperate with a person. The robot system 1 of the present embodiment is installed in a factory that manufactures industrial products such as transport machines and electrical equipment. The production line provided in the factory is equipped with a conveyor device such as a belt conveyor or a roller conveyor. With the conveyor device, an unfinished workpiece is placed on a support stand or the like from the upstream side to the downstream side. It flows toward. A plurality of robot main bodies 2 are arranged side by side from the upstream side to the downstream side on the side of the transfer device. Each robot body 2 performs predetermined operations such as assembly of parts, welding, and painting on unfinished workpieces. In the present embodiment, there is a place where a human work area is arranged in the vicinity of (for example, adjacent to) the work area of the robot body 2 in the production line of the factory. That is, there is a case where the robot main body 2 performs assembly work along with people on the production line. As a result, for example, the robot main body 2 can share the mechanical work that can be performed in accordance with the manual operation, and the person can share the delicate work that is difficult unless it is performed manually. Thus, the work can be efficiently completed. .

  However, when the robot body 2 and a person work together, it is necessary to take sufficient measures for human safety. In general, in order to reduce the threat to the human body of the robot body 2, the operation speed of the robot body 2 is set to be safe in order to prevent a great damage even if the robot body 2 contacts the person. It is possible to reduce the speed. However, if the operating speed of the robot body 2 is reduced even when it is not necessary and urgent, the production efficiency will be lowered. In consideration of such points, the robot system 1 according to the present embodiment performs specific control for ensuring both safety and improvement of production efficiency, which were difficult to achieve in the past. The details of the control performed by the robot system 1 will be described in detail later.

  As shown in FIG. 1, a robot system 1 includes a robot body 2, an end effector (tool) 3, a plurality of distance sensors 4, a robot controller (control unit) 5, and a collision prevention controller (collision prevention control unit). 8 is mainly provided.

  The robot body 2 is a known industrial articulated robot, and has a multi-joint arm 11 having a plurality of joints. Each joint is provided with an actuator. By adjusting the driving force applied to these actuators, each arm is rotated at a desired speed by a desired angle. Thereby, it is possible to cause the robot body 2 to perform a desired operation.

  The end effector 3 is a part (tool) having a function of directly acting on the workpiece, and is attached to the tip of the multi-joint arm 11. Various end effectors 3 to be mounted are conceivable. For example, a gripper or a multi-finger hand can be used. Wires, tubes, and the like that are connected to the end effector 3 from an electric motor, a control device, and the like are routed along the longitudinal direction of the articulated arm 11. As a result, driving force and electrical signals are transmitted to the end effector 3.

  The distance sensor 4 of the present embodiment is a sensor attached to a plurality of locations on the surface of the robot body 2 and the surface of the end effector 3 attached to the robot body 2. In this embodiment, a flexible printed circuit board in which a plurality of photoelectric sensors are arranged in an array is attached to the surface of the robot main body 2 and the surface of the end effector 3 attached to the robot main body 2, so that a large number of distance sensors can be obtained. 4, 4,... Are attached to the robot body 2 and the end effector 3.

  In the present embodiment, each distance sensor 4 is configured as a photoelectric sensor, and includes a light projecting unit and a light receiving unit. Light such as visible light and infrared light (detection light having an appropriate wavelength) is irradiated from the light projecting portion of this photoelectric sensor, and light reflected by the surface of an obstacle (detection object) such as a person is received by the light receiving portion. A sensor output value is obtained in accordance with the amount of received light. This distance detection is repeatedly performed at sufficiently short time intervals. In addition, the direction in which the light projecting unit emits the detection light is substantially perpendicular to the surface of the robot body 2 or the end effector 3 at the installation location.

  The detection result (sensor output value) of the distance sensor 4 is input to the conversion device 7 and subjected to appropriate signal processing, so that a person who is positioned in a direction approximately normal to the surface from the distance sensor 4 Is converted into a signal indicating the distance to the obstacle (hereinafter, sometimes referred to as a distance signal). The distance signal output from the conversion device 7 is input to the collision prevention controller 8.

  The collision prevention controller 8 sends an appropriate command signal (collision prevention command signal) to the robot controller 5 for preventing a collision between the robot body 2 and an obstacle such as a person according to the input distance signal. Output.

  The robot body 2 and the end effector 3 are connected to the robot controller 5 via wiring or the like or via a communication network. The robot controller 5 is connected to the collision prevention controller 8 via wiring or the like or via a communication network.

  The robot controller 5 is configured as a computer and includes a CPU (arithmetic unit), a ROM, a RAM, and the like. The ROM stores (stores) an appropriate operation program for operating the robot body 2 and the end effector 3 based on control data (for example, numerical data). By cooperation of this software and hardware, the robot controller 5 operates the actuators and end effectors 3 provided at the joints of the multi-joint arms 11 of the robot body 2 as appropriate, and performs predetermined operations to the robot body 2. It is possible to function as a command unit that sends a command signal for causing the device to perform the operation.

  The collision prevention controller 8 is configured as a computer like the robot controller 5 and includes a CPU (calculation unit), ROM, RAM, and the like. The ROM determines the degree of approach between an obstacle such as a person and the robot body 2 (end effector 3) according to the input distance signal, and sends a collision prevention operation command signal for preventing a collision to the robot. An appropriate program for sending to the controller 5 is stored. A command for sending a collision prevention operation command signal to the robot controller 5 for causing the collision prevention controller 8 to perform an operation for preventing the collision with an obstacle such as a person by the cooperation of this software and hardware. It is possible to function as a part.

  Below, each structure with which the collision prevention controller 8 is provided is demonstrated in detail with reference to FIG. FIG. 2 is a block diagram showing a main configuration of the collision prevention controller 8.

  The collision prevention controller 8 includes a distance signal acquisition unit 83, a threshold storage unit 84, an approach distance determination unit 85, a collision prevention command generation unit 87, a collision prevention command transmission unit 88, a distance information transmission unit 91, and the like.

  The distance signal acquisition unit 83 acquires a distance signal obtained as a result of the distance detection performed by each of the plurality of distance sensors 4.

  The distance information transmission unit 91 transmits the distance signal acquired by the distance signal acquisition unit 83 (in other words, the detection result of each distance sensor 4) to the robot controller 5.

  The threshold storage unit 84 is a memory that stores a plurality of thresholds used to determine the degree of approach of an obstacle such as a person to the robot body 2 (or the end effector 3). In the present embodiment, a first threshold T1, a second threshold T2 that is smaller than the first threshold T1, and a third threshold T3 that is smaller than the second threshold T2 are stored in the threshold storage unit 84.

  With reference to FIG. 3, each threshold value T1, T2, T3 is demonstrated concretely. FIG. 3 is a diagram for explaining the determination contents of the plurality of threshold values T1, T2, and T3 stored in the collision prevention controller 8. All of the three threshold values T1, T2, and T3 of the present embodiment are set so that the distance sensor 4 is shorter than a limit distance at which the reflected wave from an obstacle such as a person can be detected. As described above, the second threshold T2 is smaller than the first threshold T1, and the third threshold T3 is smaller than the second threshold T2 (T1> T2> T3). Therefore, it can be said that these threshold values T1, T2, and T3 are for determining the degree of danger of collision between an obstacle such as a person and the robot body 2.

  The approach distance determination unit 85 determines the degree of approach of the person or the like to the robot body 2 obtained from the distance signal acquired by the distance signal acquisition unit 83 in a stepwise manner. More specifically, the approach distance determination unit 85 determines the magnitude relationship between the approach distance L of the person such as the robot body 2 (or the end effector 3) and the three threshold values T1, T2, and T3.

  The collision prevention command generation unit 87 performs an appropriate operation on the robot body 2 to prevent a collision between the robot body 2 (or the end effector 3) and a person or the like according to the determination result in the approach distance determination unit 85. A collision prevention command signal for generating

  This will be specifically described below. As a result of the determination by the approach distance determination unit 85, when the approach distance L of the person or the like to the robot body 2 (or the end effector 3) exceeds the first threshold value T1, the person or the like and the robot body 2 collide (contact). There is little need to consider the possibility of doing so. Therefore, in this case, the collision prevention command generation unit 87 does not generate a collision prevention command signal.

  As a result of the determination by the approach distance determination unit 85, when the approach distance L is equal to or less than the first threshold value T1, the collision prevention command generation unit 87 considers that the robot body 2 is somewhat close to a person or the like. A low-speed operation command signal that is a command for causing the operation (work) to be performed at a lower speed than normal (that is, when the approach distance L exceeds the first threshold value T1) is generated.

  As a result of the determination by the approach distance determination unit 85, if the approach distance L is equal to or less than the second threshold value T2, the possibility that the robot body 2 will collide with an obstacle such as a person is somewhat increased. Generates a retreat operation command signal that is a command for continuing the work while retreating the robot body 2 away from a person or the like.

  As a result of the determination by the approach distance determination unit 85, when the approach distance L is equal to or smaller than the third threshold value T3, it can be said that an obstacle such as a person is close to the robot body 2 and the risk of collision is high. Therefore, in this case, the collision prevention command generation unit 87 generates a stop command signal that is a command for stopping the operation of the robot body 2.

  The collision prevention command transmission unit 88 sends the collision prevention command signal generated by the collision prevention command generation unit 87 (specifically, the low speed operation command signal, the retreat operation command signal, and / or the stop command signal) to the robot controller 5. Send.

  Note that the low-speed operation command signal, the retreat operation command signal, and the stop command signal described above are not selectively transmitted to the robot controller 5, but can be transmitted in an appropriate combination. For example, when the approach distance L is equal to or less than the second threshold value T <b> 2, the low speed operation command signal and the retreat operation command signal are transmitted to the robot controller 5. When the approach distance L is equal to or smaller than the third threshold value T3, the low speed operation command signal, the retreat operation command signal, and the stop command signal are transmitted to the robot controller 5.

  Below, each structure with which the robot controller 5 is provided is demonstrated in detail with reference to FIG. FIG. 4 is a block diagram showing the main configuration of the robot controller 5. FIG. 5 is a diagram illustrating an operation program stored in the robot controller 5.

  As shown in FIG. 4, the robot controller 5 includes an operation program storage unit 51, a collision prevention command reception unit 52, a space determination unit 53, a retraction correction value calculation unit 55, a target position update unit 56, a distance transition storage unit 57, an operation A speed control unit 58, a control signal transmission unit 59, a collision prevention control unit 60, a distance information reception unit 64, a retreat permission / prohibition determination unit 65, and the like are provided.

  The operation program storage unit 51 stores an operation program in which one or more operation steps to be performed by the robot body 2 are described. By executing the operation program read from the operation program storage unit 51, it is possible to cause the robot body 2 to perform a predetermined operation.

  By the way, in the present embodiment, there is a case where the operation is continued while the robot main body 2 performs the retreat operation as described above. However, the operation performed by the robot main body 2 is slightly misaligned depending on the purpose of the operation. There are what is allowed and what is not. In this regard, in the present embodiment, it is possible to distinguish and describe the work that allows the positional deviation of the robot body 2 and the work that is not so in the operation program.

  In the example of the operation program shown in FIG. 5, the prohibition of the evacuation operation (EVASION_END) is described immediately before the operation step (for example, a series of operation steps describing the pick-and-place operation) that cannot allow the positional deviation of the robot body 2. Has been. Immediately after a series of operation steps that describe work in which the positional deviation of the robot main body 2 cannot be permitted, permission for retreat operation (EVASION_START) is described. As a result, it is possible to clearly indicate on the program an operation in which the displacement of the position of the robot main body 2 is not allowable and an allowable operation.

  The collision prevention command receiving unit 52 receives a collision prevention command signal transmitted from the collision prevention controller 8.

  The collision prevention control unit 60 performs control for operating the robot body 2 so as not to collide with an obstacle such as a person based on the collision prevention command signal received by the collision prevention command receiving unit 52. The collision prevention operation performed by the robot body 2 includes a “low-speed operation” in which the robot body 2 is operated at a lower speed than normal, and the robot body 2 is retreated (moved) in a direction away from an obstacle such as a person. There are “retreat operation” to be continued and “stop” to stop the operation of the robot body 2 main body. The collision prevention control unit 60 appropriately operates the robot body 2 in accordance with the type of command signal received by the collision prevention command receiving unit 52 (low speed operation command signal, retraction operation command signal, or stop command signal).

  The retreat permission / prohibition determination unit 65 determines whether or not the retreat operation of the robot body 2 is permitted in the operation program. The evacuation permission / prohibition determination unit 65 refers to the operation program stored in the operation program storage unit 51 and permits the evacuation operation in the operation step describing the operation to be performed by the robot body 2 from now on. It is determined whether or not it has been done. In the example of FIG. 5, when an operation step after a description (EVASION_END) for prohibiting the save operation and before a description (EVASION_START) for permitting the save operation is to be executed, allow / prohibit save. The determination unit 65 determines that the retreat operation is prohibited.

  The space determination unit 53 determines whether or not it is possible to cause the robot body 2 to perform a retraction operation based on a retraction correction value calculated by a retraction correction value calculation unit 55 described later. The space determination unit 53 uses the first determination space S1 and the second determination space S2 to determine whether or not the robot body 2 can perform a reasonable retreat operation (specifically, the robot body 2) whether or not the retreat operation can be performed while always securing a margin around 2.

  Details of the determination performed by the space determination unit 53 will be described in more detail with reference to FIG. FIG. 6 is a diagram schematically illustrating a spatial determination performed by the robot controller 5 in order to acquire a feasible retreat operation.

  The first determination space S1 is a virtual space comprehensively including a space in which the robot body 2 and the end effector 3 can be moved when the robot body 2 is retracted, and is determined by calculation. The first determination space S1 is obtained as a rectangular parallelepiped space, for example.

  The second determination space S2 is a virtual space that includes representative points set in the robot body 2 and the end effector 3 and moves together with the representative points. The second determination space S2 is obtained as a spherical or cylindrical space centered on the representative point, for example. This representative point can be set for each joint of the multi-joint arm 11 and the end effector 3, for example.

  The space determination unit 53 of the present embodiment causes the robot main body 2 to perform a retreat operation in a state where the second determination space S2 is always included in the first determination space S1 (does not protrude outside the first determination space S1). It is determined by performing a three-dimensional simulation. As a result of the simulation, the space determination unit 53 only performs the retraction operation when the robot body 2 can perform the retraction operation with the second determination space S2 always included in the first determination space S1. Is determined to be possible.

  The target position acquisition unit 54 reads an operation program for operating the robot body 2 from the operation program storage unit 51 and acquires the target position of the robot body 2 by referring to the description.

  The evacuation correction value calculating unit 55 (1) has received the evacuation operation command signal from the collision prevention command receiving unit 52, and (2) an operation to be performed by the robot body 2 from now on is an evacuation operation on the operation program. The evacuation correction value is calculated when the operation corresponds to an operation step performed while the operation is permitted. When the conditions (1) and (2) are satisfied, the retraction correction value calculation unit 55 calculates a retraction correction value based on the distance information obtained by the distance information reception unit 64. Specifically, the retraction correction value is determined so that the robot body 2 is moved away from the obstacle after the positional relationship between the robot body 2 and the obstacle is obtained based on the detection results of the one or more distance sensors 4. Calculated as appropriate.

  The target position update unit 56 adds the retraction correction value calculated by the retraction correction value calculation unit 55 to the target position acquired by the target position acquisition unit 54 when the robot main body 2 is to perform the retraction operation. Thus, the target position is updated. The updated target position indicates the target position of the robot main body 2 when the robot main body 2 performs the retraction operation (the control position of the robot main body 2 when the retraction operation is taken into consideration). However, if the space determination unit 53 determines that the movement to the new target position is not possible spatially, the update of the target position is canceled (as a result, the retreat operation is not performed).

  The distance transition storage unit 57 stores the distance information acquired by the distance information receiving unit 64, specifically, the distance L from the surface of the robot body 2 (or the end effector 3) to an obstacle such as a person in association with time. , The transition of the distance L is accumulated.

  The operation speed control unit 58 controls the speed at which the robot body 2 is moved to the target position. Specifically, the operation speed control unit 58 operates the robot body 2 at a normal speed (for example, a speed determined by the operation program) when the collision prevention command receiving unit 52 has not received the low speed operation command. Let On the other hand, when the collision prevention command receiving unit 52 receives the low speed operation command, the robot body 2 is operated at a lower speed than normal, for example, at a speed of 50%.

  The operation speed control unit 58 also controls the speed at which the robot main body 2 is retracted (away from the obstacle) when the robot main body 2 performs the retraction operation. Specifically, the operation speed control unit 58 of the present embodiment refers to the contents of the distance transition storage unit 57, and as the speed at which an obstacle such as a person approaches the robot body 2 or the end effector 3 increases, the robot Control is performed so that the speed of retracting the main body 2 is increased.

  The control signal transmission unit 59 includes the target position obtained by the target position acquisition unit 54 (or the updated target position when updated by the target position update unit 56), the operation speed indicated by the operation speed control unit 58, Based on the above, a control signal is sent to the actuator of the robot body 2 to operate it.

  Hereinafter, the flow of processing performed by the collision prevention controller 8 in order to send the collision prevention command signal for causing the robot body 2 to perform the collision prevention operation to the robot controller 5 will be described in detail with reference to FIG. . FIG. 7 is a flowchart showing processing performed by the collision prevention controller 8.

  The collision prevention controller 8 sends a collision prevention command for causing the robot body 2 to perform a collision prevention operation (either low speed operation, retraction operation, or stop) to the robot controller 5 from step S101 to step S113. Process.

  First, the distance signal acquisition unit 83 of the collision prevention controller 8 acquires the approach distance L to the robot body 2 (or the end effector 3) of an obstacle such as a person (an obstacle detected by the distance sensor 4) in step S101. To do.

  Subsequently, the approach distance determination unit 85 of the collision prevention controller 8 compares the approach distance L acquired in step S101 with the first threshold T1 read from the threshold storage unit 84, so that the approach distance L is the first. It is determined whether or not it is equal to or less than a threshold value T1 (step S102). Specifically, for example, it is determined whether the shortest approach distance L among the detection results acquired from the plurality of distance sensors 4 is equal to or less than the first threshold T1.

  If the approach distance L is equal to or less than the first threshold T1 as a result of the determination in step S102 (step S102, Yes), the collision prevention command generation unit 87 generates a low speed operation command signal as a collision prevention command, and this low speed operation command A signal is transmitted to the robot controller 5 by the collision prevention command transmitter 88 (step S103).

  On the other hand, as a result of the determination in step S102, if the approach distance L exceeds the first threshold value T1 (No in step S102), the low speed operation command signal is not generated, and instead, the low speed operation command signal is transmitted at the present time. It is determined whether or not it has been performed (step S104). When the low speed operation command signal has been transmitted (step S104, Yes), the collision prevention command generation unit 87 cancels the low speed operation and automatically returns the robot body 2 to normal work. Is transmitted to the robot controller 5 (step S105). Thereafter, the collision prevention command generation unit 87 performs a process of sending a retreat operation release signal and a stop release signal to the robot controller 5 as necessary (step S108, step S109, step S112, and step S113), and then proceeds to step S101. Return. When the low-speed operation command signal is not transmitted (No at Step S104), the process returns to Step S101.

  After step S103, the approach distance determination unit 85 of the collision prevention controller 8 compares the approach distance L acquired in step S101 with the second threshold value T2 read from the threshold value storage unit 84, thereby obtaining the approach distance L. It is determined whether or not it is equal to or less than the second threshold T2 (step S106).

  As a result of the determination in step S106, when the approach distance L is equal to or smaller than the second threshold T2 (step S106, Yes), the collision prevention command generation unit 87 generates a retraction operation command signal as a collision prevention command, and this retraction operation command A signal is transmitted to the robot controller 5 by the collision prevention command transmission unit 88 (step S107).

  On the other hand, if the approach distance L is greater than the second threshold value T2 as a result of the determination in step S106 (No in step S106), the retraction operation command signal is not generated, and instead, the retraction operation command signal is transmitted at the present time. It is determined whether or not it has been made (step S108). If the retraction operation command signal has been transmitted (step S108, Yes), the collision prevention command generation unit 87 transmits a retraction operation cancel signal for canceling the retraction operation to the robot controller 5 (step S109). Thereafter, the collision prevention command generation unit 87 performs a process of sending a stop release signal to the robot controller 5 as necessary (steps S112 and S113), and returns to step S101. If the evacuation operation command signal has not been transmitted (No at Step S108), the process returns to Step S101.

  After step S107, the approach distance determination unit 85 of the collision prevention controller 8 compares the approach distance L acquired in step S101 with the third threshold value T3 read from the threshold value storage unit 84, thereby obtaining the approach distance L. It is determined whether or not it is equal to or less than a third threshold value T3 (step S110).

  As a result of the determination in step S110, when the approach distance L is equal to or smaller than the third threshold T3 (step S110, Yes), the collision prevention command generation unit 87 generates a stop command signal as a collision prevention command, and the stop command signal It is transmitted to the robot controller 5 by the collision prevention command transmitter 88 (step S111).

  On the other hand, if the approach distance L is greater than the third threshold value T3 as a result of the determination in step S110 (No in step S110), a stop command signal is not generated, but instead, is a state in which the stop command signal is transmitted at this time? It is determined whether or not (step S112). When the stop command signal has been transmitted (step S112, Yes), the collision prevention command generation unit 87 transmits a stop cancel signal for canceling the stop to the robot controller 5 (step S113). Then, it returns to step S101.

  Through the above processing, when an obstacle such as a person approaches the robot main body 2, a command for causing the robot main body 2 to perform a collision prevention operation is performed in the order of a low speed operation command, a retreat operation command, and a stop command. be able to. In addition, when the obstacle moves away from the robot body 2 thereafter, the above commands can be canceled in the order of a stop command, a retreat operation command, and a low speed operation command.

  Next, a flow of processing performed by the robot controller 5 in order to cause the robot body 2 to perform a collision prevention operation according to the collision prevention command from the collision prevention controller 8 will be described with reference to FIG. FIG. 8 is a flowchart showing processing performed by the robot controller 5 in relation to the collision prevention command.

  The robot controller 5 causes the robot body 2 to perform any one of a collision prevention operation of low speed operation, retreat operation, or stop according to the degree of approach of the human body or the like to the robot body 2 (or the end effector 3). The processes from step S201 to step S210 are performed.

  First, the collision prevention command receiving unit 52 of the robot controller 5 receives the collision prevention command signal sent from the collision prevention command transmitting unit 88 of the collision prevention controller 8, thereby acquiring the collision prevention command (step S201). ).

  Subsequently, the collision prevention control unit 60 determines whether or not a low speed operation command has been received (step S202).

  If the result of determination in step S202 is that a low speed operation command has not been received (step S202, No), processing returns to step S201.

  As a result of the determination in step S202, if a low speed operation command has been received (step S202, Yes), the operation speed control unit 58 of the robot controller 5 determines the operation speed of the actuator provided in the robot body 2 as normal. Control is performed so that the speed is lower than that (step S203). Thereby, the work by the robot body 2 can be continued while taking into account the possibility of collision with surrounding obstacles to some extent.

  After step S203, the collision prevention control unit 60 determines whether an evacuation operation command has been received (step S204).

  If the result of determination in step S204 is that a save operation command has not been received (step S204, No), processing returns to step S201.

  As a result of the determination in step S204, if a retraction operation command has been received (step S204, Yes), the retraction permission / prohibition determination unit 65 of the robot controller 5 stores the operation program stored in the operation program storage unit 51. Referring to this, it is determined whether or not the retreat operation is permitted in the operation step describing the operation to be performed by the robot body 2 (step S205). As a result of the determination in step S205, if the save operation is prohibited (No in step S205), the process returns to step S201. Thereby, when the retracting operation is prohibited in the operation program, the robot body 2 can be prevented from performing the retracting operation.

  As a result of the determination in step S205, if the retreat operation is permitted (step S205, Yes), the retraction correction value calculation unit 55 of the robot controller 5 continues based on the distance information received by the distance information reception unit 64. Then, a retraction correction value to be added to the target position acquired by the target position acquisition unit 54 is calculated (step S206).

  Next, the space determination unit 53 determines whether or not the retraction operation to be performed by the robot body 2 is spatially possible based on the target position and the retraction correction value (step S207).

  As a result of the determination in step S207, if the evacuation operation is spatially impossible (No in step S207), the process returns to step S201. Thereby, it is possible to prevent the robot body 2 from performing an excessive retreat operation.

  As a result of the determination in step S207, when the retreat operation is spatially possible (step S207, Yes), the target position update unit 56 of the robot controller 5 generates target position information for realizing the retreat operation. Specifically, the target position update unit 56 generates a corrected target position by adding the above-described retraction correction value to the target position acquired by the target position acquisition unit 54, and the control signal transmission unit 59 Then, a control signal based on the new target position is transmitted (step S208). Thereby, the operation can be continued while the robot body 2 is retracted in a direction away from a person or the like. Therefore, compared to the case where the robot body 2 is not retracted, the threat to the person of the robot body 2 can be reduced, and the production efficiency is not significantly impaired.

  After step S208, the collision prevention control unit 60 of the robot controller 5 determines whether or not a stop command has been received (step S209). When the stop command has been received (step S209, Yes), the collision prevention control unit 60 controls the control signal transmission unit 59 to transmit a stop signal to the actuators and end effectors 3 of the joints of the robot body 2. (Step S210). As a result, the operations (operations) of the robot body 2 and the end effector 3 are stopped, so that the possibility that a person or the like collides with the robot body 2 is reduced as compared with the case where the operation is continued in the robot body 2. . Thereafter, the process returns to step S201.

  If the result of determination in step S209 is that a stop command has not been received (step S209, No), processing in step S210 is skipped and processing returns to step S201.

  Although not shown in the flowchart of FIG. 8, when the retracting operation command received by the robot controller 5 is canceled after the retracting operation described in step S <b> 208 is performed, the collision prevention control of the robot controller 5 is performed. The unit 60 automatically controls the robot main body 2 so as to eliminate the positional deviation caused by the retreat operation. Thereby, it is possible to resume the predetermined work in a state where the influence of the past retreat operation is removed (at the position as defined by the operation program).

  As described above, the robot system 1 of the present embodiment includes the robot body 2, the robot controller (control unit) 5, the at least one distance sensor (detection unit) 4, and the collision prevention controller (collision prevention control unit). 8). The robot controller 5 controls the operation of the robot body 2 to perform work. The distance sensor 4 is attached to the surface of the robot body 2 or an end effector (tool) 3 attached to the robot body 2, and is a distance (approach distance) L to an obstacle such as a person positioned in a direction substantially normal to the surface. Can be detected. The collision prevention controller 8 sends to the robot controller 5 a command for operating the robot body 2 so as to avoid a collision with an obstacle such as a person according to the detection result of the distance sensor 4. The collision prevention controller 8 stores a plurality of threshold values T1, T2, and T3 for determining the degree of approach of an obstacle such as a person to the robot body 2 or the end effector 3. When the detection result of the distance sensor 4 is equal to or less than the first threshold value T1, the collision prevention controller 8 causes the robot body 2 to operate at a lower speed than when the detection result of the distance sensor 4 exceeds the first threshold value T1. Sends a low speed operation command. When the detection result of the distance sensor 4 is equal to or smaller than the second threshold value T2, which is smaller than the first threshold value T1, the collision prevention controller 8 continues the operation while retracting the robot body 2 away from an obstacle such as a person. One of a retreat operation command that is a command for the operation and a stop command that is a command for stopping the operation of the robot body 2 is sent. When the detection result of the distance sensor 4 is equal to or smaller than the third threshold value T3 that is smaller than the second threshold value T2, the collision prevention controller 8 sends either the retraction operation command or the stop command.

  As a result, the frequency at which the work is stopped can be suppressed by continuing the work while the robot body 2 is made slower than usual or by continuing the work while evacuating. Therefore, for example, a significant decrease in production efficiency can be suppressed while ensuring safety when a person or the like as an obstacle approaches the robot body 2 or the end effector 3.

  In the present embodiment, the collision prevention controller 8 is provided separately from the robot controller 5, but the CPU of the collision prevention controller 8 is omitted, and the control shown in FIG. May be used. In other words, a configuration in which the collision prevention controller 8 is integrated into the robot controller 5 may be employed.

  In this case, the configuration related to the control of the robot system 1 can be simplified by sharing the configuration.

  In the robot system 1 of the present embodiment, the space determination unit 53 of the robot controller 5 defines a first determination space S1 and a second determination space S2 shown in FIG. It is determined whether or not it is possible. The first determination space S1 comprehensively includes a space in which the robot body 2 and the end effector 3 can be moved when the robot body 2 is retracted. The second determination space S2 includes representative points set in at least one of the robot body 2 and the end effector 3, and moves together with the representative points. The robot controller 5 causes the robot body 2 to perform the retreat operation within a range where the second determination space S2 is included in the first determination space S1.

  This makes it possible to acquire a feasible save operation with simple logic. Further, the robot body 2 can be retreated in a predetermined space while always ensuring a margin around the robot body 2 and the like.

  Further, in the robot system 1 of the present embodiment, the robot controller 5 is configured to be able to operate the robot body 2 according to one or more operation steps described in the input operation program. As shown in FIG. 5, the operation program is configured to include a description for permitting or prohibiting the save operation. The retreat permission / prohibition determination unit 65 of the robot controller 5 executes the operation step after the description for prohibiting the retreat operation (EVASION_END) and before the description for permitting the retreat operation (EVASION_START). In this case, the robot body 2 is controlled not to perform the retreat operation.

  As a result, among the series of operation steps included in the operation program, the operation steps that permit the saving operation and the operation steps that are prohibited can be clearly indicated by the description of the operation program. Therefore, for example, when performing an operation in which the displacement of the position of the robot body cannot be permitted, such as a pick-and-place operation, the robot system 1 can be clearly instructed in the operation program not to perform the retreat operation.

  Further, in the robot system 1 of the present embodiment, the robot controller 5 operates the robot body 2 so as to eliminate the positional deviation caused by the retreat operation performed in the past after the retreat operation command is canceled. .

  As a result, it is possible to cause the robot body 2 to perform normal work after removing the influence of the past retreat operation.

  Further, in the robot system 1 of the present embodiment, the target position update unit 56 of the robot controller 5 performs the robot main body 2 with respect to the designated target position of the robot main body 2 when the robot main body 2 is retracted. The target position is updated by adding a correction value (retraction correction value) in a direction away from an obstacle such as a person, and the robot body 2 is controlled to reach the updated target position.

  Thereby, the specific movement when the robot body 2 is retracted can be obtained by calculation.

  In the robot system 1 of the present embodiment, the operation speed control unit 58 of the robot controller 5 controls the speed at which the robot body 2 is retracted based on the change over time of the detection result of the distance sensor 4.

  Thereby, the speed at which the robot body 2 is retracted can be changed according to the speed at which an obstacle such as a person approaches the robot body 2. Therefore, it is possible to cause the robot main body 2 to perform an appropriate operation according to the degree of urgency of the change in the situation.

  The collision prevention controller 8 may store one or a plurality of further threshold values (threshold values for speed reduction) that are smaller than the first threshold value T1. With this configuration, the robot controller 5 controls the robot body 2 so that the operation speed of the robot body 2 becomes lower as the detection result (approach distance L) of the distance sensor 4 is smaller than the threshold value. .

  In this case, as an obstacle such as a person approaches the robot body 2, the operation of the robot body 2 can be gradually reduced, and the speed of the robot body 2 can be finely reduced.

  In the robot system 1 of the present embodiment, the collision prevention controller 8 sends the low speed operation command when the detection result of the distance sensor 4 exceeds the first threshold T1 after sending the low speed operation command to the robot controller 5. To release. The collision prevention controller 8 cancels the retraction operation command when the detection result of the distance sensor 4 exceeds the second threshold value T2 after sending the retraction operation command to the robot controller 5. Furthermore, the collision prevention controller 8 cancels the stop command when the detection result of the distance sensor 4 exceeds the third threshold value T3 after sending the stop command to the robot controller 5.

  As a result, when the distance to the obstacle such as a person (approach distance L) is increased and the risk of collision is reduced, the robot body 2 can be restored in stages so that the operation becomes normal. Production efficiency can be improved.

  The timing at which the distance sensor 4 repeatedly detects the distance (approach distance L) may be configured to be changeable by setting of a sensor control device (not shown), for example. Moreover, you may comprise so that the wavelength of the detection light used for the detection of the distance sensor 4 can be changed with the setting of the said sensor control apparatus.

  For example, when operating a plurality of robot systems 1, 1,..., The detection timing of the distance sensor 4 and the wavelength of light used for detection are different between the robot systems 1, 1,. By setting to, the distance sensor 4 of each robot body 2 can detect the distance (approach distance L) with an obstacle such as a person well without being affected by other influences.

  The preferred embodiment of the present invention has been described above, but the above configuration can be modified as follows, for example.

  In the above embodiment, the distance sensor 4 detects the distance L between the person as an example of the obstacle and the robot main body 2 or the end effector 3, but the obstacle is not limited to the person. For example, it is good also as a work trolley etc. which drive | work in a factory.

  In the above embodiment, when the approach distance L detected by the distance sensor 4 is equal to or smaller than the second threshold value T2 and exceeds the third threshold value T3, the robot body 2 is caused to perform a retreat operation, and the approach distance L is In the case of the third threshold value T3 or less, the robot body 2 is stopped. However, the present invention is not necessarily limited to this. That is, instead of this, the robot body 2 is stopped when the approach distance L is equal to or less than the second threshold value T2 and exceeds the third threshold value T3, and when the approach distance L is equal to or less than the third threshold value T3. It is good also as what makes the robot main body 2 perform retraction | saving operation | movement.

  In the above embodiment, the distance sensor 4 is a photoelectric sensor including a light projecting unit and a light receiving unit. However, the configuration of the sensor is not limited to this. For example, instead of this, an ultrasonic sensor or the like is used. Also good.

  In the above embodiment, the space determination unit 53 defines the space that comprehensively includes the position where the robot body 2 and the end effector 3 can be moved when the robot body 2 is retracted as the first determination space S1. However, it is not limited to this. That is, instead of this, a space that comprehensively includes positions where the robot body 2 and the end effector 3 cannot move when the robot body 2 is retracted may be defined as the first determination space. In that case, the robot controller 5 may cause the robot body 2 to perform the retreat operation within a range where the second determination space S2 does not overlap with the first determination space.

  In the above embodiment, the representative points set when the space determination unit 53 determines the second determination space S2 are arranged at each joint of the multi-joint arm 11 and the end effector 3, respectively. However, the number and arrangement of the representative points are arbitrary. For example, a plurality of representative points may be arranged in the middle of each of the plurality of arms constituting the multi-joint arm 11.

  In the above-described embodiment, after the operation of the robot body 2 is stopped based on the stop command, if the detection result of the distance sensor 4 exceeds the third threshold value T3, the stop of the robot body 2 is automatically released. It is configured. However, not only the detected distance exceeds the third threshold T3 but also the stop of the robot body 2 is released only when there is an explicit manual operation (for example, an operation of pressing the recovery button) by the operator. It may be configured. Similarly, the release of the low-speed operation and the release of the retracting operation may be performed on the condition of manual operation.

  In the transition period in which the normal operation is shifted to the low-speed operation in accordance with the low-speed operation command, the operation speed control unit 58 of the robot controller 5 determines that an obstacle such as a person is a robot based on the change over time of the detection result of the distance sensor 4. The robot body 2 may be controlled to decelerate more rapidly as the speed of approaching the body 2 or the end effector 3 increases.

  In the above embodiment, when the approach distance L gradually increases from the state in which the low speed operation command, the retreat operation command, and the stop command are sent, the collision prevention controller 8 determines the third threshold value based on the flowchart of FIG. The stop command is canceled when it exceeds T3, the retreat operation command is canceled when it exceeds the second threshold T2, and the low-speed operation command is canceled when it exceeds the first threshold T1. However, instead of restoring the operation of the robot body 2 stepwise according to the approach distance L in this way, for example, when the approach distance L exceeds the first threshold value T1, the three commands are canceled at once. It may be a thing.

  In the above embodiment, the robot controller 5 receives the retracting operation command, but the retracting operation is prohibited (No in step S205 in FIG. 8), or the retracting operation is determined to be spatially impossible. (Step S207, No), the robot body 2 is controlled so as to continue the operation without performing the retreat operation. However, instead of this, control for stopping the robot body 2 in the above case may be performed.

  A plurality of robot systems 1 may communicate with each other and automatically adjust the detection timing of each distance sensor 4 and the wavelength of detection light so as not to affect the detection results of each other. Good.

  In the above embodiment, the tool mounted on the robot body 2 is the end effector 3, but this is not a limitation. For example, the tool may be attached to a place other than the tip of the robot body 2.

  In the above embodiment, the robot body 2 is illustrated as having a structure including one articulated arm 11 (see FIG. 1), but the robot body to which the present invention is applied has one articulated arm. The robot main body is not limited to the robot main body having only two, and may be, for example, a robot main body having two articulated arms in pairs. Further, the number of joints may be singular. For example, the present invention can be applied even to a robot whose arm rotates only in the horizontal direction.

1 Robot system 2 Robot body 3 End effector (tool)
4 Distance sensor (detection unit)
5 Robot controller (control unit)
L Approach distance (distance)
T1 first threshold T2 second threshold T3 third threshold

Claims (10)

The robot body,
A control unit for controlling the operation of the robot body and performing work;
At least one detection unit that is attached to the surface of the robot body or a tool attached to the robot body and that can detect a distance to an obstacle located in a direction substantially normal to the surface;
In accordance with the detection result of the detection unit, a collision prevention control unit that sends a command for operating the robot body to avoid a collision with the obstacle to the control unit,
With
The collision prevention control unit stores a plurality of threshold values for determining the degree of approach of the obstacle to the robot body or the tool,
The collision prevention control unit
When the detection result of the detection unit is less than or equal to a first threshold value, a low-speed operation command that is a command for causing the robot body to operate at a lower speed than when the detection result of the detection unit exceeds the first threshold value. Send,
A retraction operation command that is a command for continuing the operation while retreating the robot main body in a direction away from the obstacle, when the detection result of the detection unit is equal to or smaller than a second threshold smaller than the first threshold; Or, any one of stop commands that are commands for stopping the operation of the robot body is sent,
When the detection result of the detection unit is equal to or smaller than a third threshold value that is smaller than the second threshold value, the robot system sends either the retraction operation command or the stop command. The robot system according to claim 1,
The robot system according to claim 1, wherein the collision prevention control unit performs control using a calculation unit included in the control unit. The robot system according to claim 1 or 2,
A first determination space that comprehensively includes a space in which the robot body and the tool can be moved or cannot be moved when the robot body is retracted;
A second determination space that includes a representative point set in the robot body or the tool and moves together with the representative point;
Is established,
The control unit causes the robot body to perform the retreat operation in a range in which the second determination space is included in the first determination space or in a range in which the second determination space does not overlap the first determination space. A robot system characterized by this. The robot system according to any one of claims 1 to 3, wherein
The control unit is configured to be able to operate the robot body according to one or more operation steps described in the input operation program,
The operation program is configured to include a description for permitting or prohibiting the save operation,
The controller does not perform the retraction operation of the robot body when the operation step is executed after the description prohibiting the retraction operation and before the description permitting the retraction operation. Characteristic robot system. The robot system according to any one of claims 1 to 4, wherein
The controller is configured to operate the robot body so as to eliminate a positional shift caused by the retraction operation performed in the past after the retraction operation command is canceled. A robot system according to any one of claims 1 to 5, wherein
The control unit adds a correction value in a direction in which the robot body is moved away from the obstacle to the target position of the designated robot body when the robot body is to be retracted. And the robot body is controlled to reach the updated target position. The robot system according to any one of claims 1 to 6, wherein
The control unit controls a speed at which the robot main body is retracted based on a change over time in the detection result of the detection unit. The robot system according to any one of claims 1 to 7,
The collision prevention control unit stores one or more additional threshold values that are smaller than the first threshold value,
The controller is
The robot system is characterized in that the robot body is controlled such that the lower the detection result of the detection unit is, the lower the threshold value, the slower the operation speed of the robot body. The robot system according to any one of claims 1 to 8,
The collision prevention control unit
After sending the low speed operation command, if the detection result of the detection unit exceeds the first threshold, cancel the low speed operation command,
After sending one of the retreat operation command or the stop command, when the detection result of the detection unit exceeds the second threshold, cancel the one command,
A robot system that cancels the other command when the detection result of the detection unit exceeds the third threshold value after sending either one of the retreat operation command or the stop command. . The robot system according to any one of claims 1 to 9,
A robot system configured to be able to change a timing at which the detection unit repeatedly detects the distance or a wavelength of detection light used for detection by the detection unit.

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