Collaborative robot system

Abstract

To provide a cooperative robot system in which a plurality of cooperative robots can perform a retreat operation in cooperation.SOLUTION: A cooperative robot system 100 according to the present invention includes a plurality of robots 112a and 112b having external force sensors 102A and 102B, a collision detection device 116 that detects that at least one of the plurality of robots has collided with a worker H based on an output of the external force sensor, an operation determination device 118 that switches an operation mode of the robot from an automatic operation mode to a standby mode based on the detection by the collision detection device, and a retreat control device 130 that causes the plurality of robots to execute a retreat operation. When an external force is applied to one robot 102A during the standby mode, the retreat control device performs a separation operation of retreating the robot and operating another robot 102B adjacent to the retreated robot in a direction opposite to the direction of the retreated robot.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a collaborative robot system with safety features. [Background technology]

[0002] Safety measures are required for industrial robots that share a work area with humans, known as collaborative robots. ISO10218-1 specifies several requirements for collaborative operation as the safety standard required for collaborative robots. To meet these requirements, collaborative robots may have a function (called a collision detection function or collision stopping function) that limits the robot's power (torque) and force and stops the robot if the limit is exceeded.

[0003] In addition to collision detection, collaborative robots may also have a retraction function, which detects when a worker pushes the robot's arm after the robot has stopped, and then retracts the arm.

[0004] Patent Document 1 describes a robot system in which multiple robots are controlled by a single control device. In this robot system, when an irregular state is detected in at least one robot (when an irregular reaction force is detected), the robot is made to perform an operation to remove the irregular state. At this time, the other robot is made to continue its operation, or both robots are made to perform a coordinated removal operation, or both robots are made to operate in coordination.

[0005] Furthermore, Patent Document 2 discloses a numerical control system for controlling a collaborative robot with an evacuation function (evacuation mode function). In this numerical control system, a person can push the arm of the collaborative robot to operate the arm and allow the person to evacuate. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 6881525 [Patent Document 2] Patent No. 7260727 Summary of the Invention [Problem to be solved by the invention]

[0007] However, the robot system in Patent Document 1 merely causes multiple collaborative robots to operate in a coordinated manner when an irregular reaction force is detected. Furthermore, Patent Document 1 does not specifically describe how to resolve the irregular state, and does not disclose the circumstances under which coordinated operation occurs.

[0008] In the numerical control system of Patent Document 2, although the collaborative robot has a function of retreating after a collision, there is no description of cooperative operation of multiple collaborative robots.

[0009] In view of the above problems, the present invention aims to provide a collaborative robot system in which multiple collaborative robots can cooperate to perform an escape operation. [Means for solving the problem]

[0010] In order to solve the above problems, a typical configuration of a collaborative robot system according to the present invention includes a plurality of robots each having an external force sensor, a collision detection device that detects that at least one of the plurality of robots has collided with an object based on the output of the external force sensor, an operation determination device that switches the operation mode of the robot from an automatic operation mode to a standby mode based on the detection by the collision detection device, and an evacuation control device that causes the plurality of robots to perform evacuation operations, wherein when an external force is applied to one robot while in standby mode, the evacuation control device causes the robot to evacuate and performs a moving-away operation that moves other robots adjacent to the evacuated robot in a direction opposite to the direction of the evacuated robot.

[0011] In order to solve the above problems, another typical configuration of a collaborative robot system according to the present invention includes a plurality of robots each having an external force sensor, a collision detection device that detects that at least one of the plurality of robots has collided with an object based on the output of the external force sensor, an operation determination device that switches the operation mode of the robot from automatic operation mode to standby mode based on the detection by the collision detection device, and an evacuation control device that causes the plurality of robots to perform evacuation operations, wherein when an external force is applied to one robot while in standby mode, the evacuation control device performs cooperative evacuation operations by causing the robot to evacuate and operating other robots that were operating cooperatively with the robot that has been evacuated so as to maintain their relative positions.

[0012] In order to solve the above problems, yet another representative configuration of a collaborative robot system according to the present invention includes a plurality of robots each having an external force sensor, a collision detection device that detects that at least one of the plurality of robots has collided with an object based on the output of the external force sensor, an operation determination device that switches the operation mode of the robot from automatic operation mode to standby mode based on the detection by the collision detection device, and an evacuation control device that causes the plurality of robots to perform evacuation operations, wherein when an external force is applied to one of the robots while in standby mode, if the program being executed when the robot collided with the object was a non-cooperative operation, the evacuation control device causes the robot to evacuate and performs a separating operation by moving other robots adjacent to the evacuated robot in a direction opposite to the direction of the evacuated robot, and if the program being executed was a cooperative operation, the evacuation control device causes the robot to evacuate and performs a cooperative evacuation operation by moving the other robots that were operating cooperatively so as to maintain their relative positions with the evacuated robot.

[0013] When an external force is applied once to each of two adjacent robots, the above-mentioned retraction control device preferably performs a spacing operation to retract the two robots to which the external force has been applied in a direction that increases the distance between them.

[0014] The above-mentioned evacuation control device preferably maintains the stop of a robot when an external force is applied to one robot multiple times within a predetermined time period.

[0015] The above-mentioned retraction control device preferably performs a moving away operation when an external force is applied to one robot multiple times within a predetermined time period.

[0016] The above-mentioned retraction control device preferably performs a cooperative retraction operation when an external force is applied to one robot multiple times within a predetermined time period. [Effects of the Invention]

[0017] According to the present invention, it is possible to provide a collaborative robot system in which a plurality of collaborative robots can cooperate to perform an escape operation. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a block diagram showing the functions of a collaborative robot system according to an embodiment of the present invention. [Figure 2] 2 is a flowchart showing the operation of the collaborative robot system of FIG. 1 in a standby mode. [Figure 3] 2 is a diagram illustrating a separation operation performed by the two robots in FIG. 1. FIG. [Figure 4] FIG. 2 is a diagram illustrating a retraction function by one of the two robots in FIG. 1. [Figure 5] 2 is a diagram illustrating a cooperative retreat operation by the two robots of FIG. 1. FIG. [Figure 6] 10 is a flowchart showing the operation of the collaborative robot system of FIG. 1 in a standby mode according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0019] Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Dimensions, materials, and other specific values ​​shown in the embodiments are merely examples for facilitating understanding of the invention and, unless otherwise specified, do not limit the present invention. In this specification and drawings, elements having substantially the same functions and configurations are designated by the same reference numerals to avoid redundant explanation, and elements not directly related to the present invention are not shown.

[0020] In the following explanation, "collaborative robot" means a robot that can work in the same space as humans and has a collision detection mechanism, speed limiting function, etc. for safety. Also, "collaborative operation" means that multiple robots work together or in unison.

[0021] 1 is a block diagram showing the functions of a collaborative robot system 100 according to an embodiment of the present invention. The collaborative robot system 100 is an industrial robot system that shares a work area with a worker H (see FIG. 3), and includes multiple (here, two) collaborative robots (hereinafter, robots 102A and 102B) and a robot control device 104.

[0022] The robots 102A and 102B are controlled by a robot controller 104 and can operate in cooperation with each other according to a program, or can operate independently. As shown in FIG. 3, the robots 102A and 102B each include an arm 106a, 106b, and an end effector 108a, 108b attached to the tip of the arm 106a, 106b, respectively.

[0023] The robots 102A and 102B also have motors 110a and 110b that drive the arms 106a and 106b, and external force sensors 112a and 112b, respectively. The external force sensors 112a and 112b are used for feedback during automatic operation mode (normal operation in which a robot program is executed). The external force sensors 112a and 112b also detect the application of an external force to the robots 102A and 102B, for example, when a worker H collides with the robots.

[0024] The robot control device 104 includes an external force calculation device 114, a collision detection device 116, an operation determination device 118, switches 120 and 122, a servo control device 124, a robot program storage device 126, a program execution device 128, an escape control device 130, and a cooperation determination device 132.

[0025] In the automatic operation mode, the program execution device 128 is in a state where it can output operation command values ​​to the servo control device 124 via the switch 122. The program execution device 128 reads out a robot program that causes the robots 102A and 102B to operate (normal operation) from the robot program storage device 126, and outputs operation command values ​​to the servo control device 124. In this way, the program execution device 128 executes the automatic operation mode of the robots 102A and 102B.

[0026] The external force calculation device 114 receives signals from the robot's external force sensors 112a and 112b. The external force calculation device 114 calculates an external force value based on the sensor values ​​output from the external force sensors 112a and 112b, and outputs the external force value to the collision detection device 116 and the evacuation control device 130. If the external force value occurs at an unexpected time or is equal to or greater than a predetermined value, the collision detection device 116 detects that the robots 102A and 102B have collided with an object, i.e., worker H, and outputs a collision detection signal to the operation determination device 118.

[0027] When a collision detection signal is input from the collision detection device 116, the operation determination device 118 turns off the switch 120 and outputs a stop instruction to the servo control device 124. The stop instruction is an instruction to urgently stop the automatic operation mode, which is the normal operation of the robots 102A and 102B. When the stop instruction is input from the operation determination device 118, the servo control device 124 outputs operation command values ​​to the motors 110a and 110b of the robots 102A and 102B, and urgently stops the automatic operation mode of the robots 102A and 102B.

[0028] Furthermore, when a collision detection signal is input from the collision detection device 116, the operation determination device 118 switches the switch 122 to switch the operation mode of the robots 102A, 102B from the automatic operation mode to the standby mode. That is, the program execution device 128 is disconnected from the servo control device 124, and the evacuation control device 130 is connected to the servo control device 124. In the standby mode, an operation command value from the evacuation control device 130 can be output to the servo control device 124 via the switch 122, as shown in FIG. 1.

[0029] After the operation mode of the robots 102A and 102B has been switched from the automatic operation mode to the standby mode, when an instruction to start automatic operation is input from an input device (operation unit 134) such as an operation button or an external system, the operation determination device 118 turns on the switch 120 and further switches the switch 122 to switch the operation mode back to the automatic operation mode.

[0030] Figure 2 is a flowchart showing the standby mode operation of the collaborative robot system 100 of Figure 1. As described above, the standby mode is initiated when the collision detection device 116 detects that the robots 102A, 102B have collided with the worker H, the operation determination device 118 turns off the switch 120, and the automatic operation mode of the robots 102A, 102B is brought to an emergency stop.

[0031] First, the evacuation control device 130 determines whether an external force has been applied to one of the robots 102A and 102B during standby mode (step S100). At this time, the evacuation control device 130 waits by repeating the process of step S100 until an external force value is input from the external force calculation device 114 (No in S100).

[0032] When an external force value is input from the external force calculation device 114 (Yes in S100), in step S102, the cooperation determination device 132 refers to the robot program stored in the robot program storage device 126 in response to an instruction from the evacuation control device 130. Then, the cooperation determination device 132 determines whether or not the command of the robot program being executed at the time of the emergency stop was a cooperative operation (whether or not it was recorded as a cooperative operation in teaching), and outputs the cooperative operation determination result to the evacuation control device 130.

[0033] Next, based on the cooperative operation determination result of the cooperative operation determination device 132, if it is determined that one robot to which an external force has been applied is not operating cooperatively, i.e., is operating non-cooperatively (step S102, No), the evacuation control device 130 determines whether there is a sufficient gap between the two robots 102A and 102B (step S104).

[0034] Figure 3 is a diagram illustrating the separation operation of the two robots 102A and 102B in Figure 1. Figure 3(a) shows a state in which the gap between the end effectors 108a and 108b of the robots 102A and 102B is narrow. The gap between the end effectors 108a and 108b (their respective positions) can be known from the coordinates of the end effectors 108a and 108b at the time of emergency stop (step S104, No).

[0035] 3(b), when an external force is applied by worker H to one of robots 102A and 102B, robot 102A, retraction control device 130 retracts robots 102A and 102B in a mirror-image manner (step S106). Specifically, retraction control device 130 retracts robot 102A in the direction of the external force indicated by arrow A, and performs a separation operation to move other robot 102B adjacent to robot 102A in the opposite direction indicated by arrow B.

[0036] The gap between the adjacent robots 102A and 102B becomes larger, allowing the worker H to escape with certainty. Therefore, according to the collaborative robot system 100, the robots 102A and 102B can cooperate to perform the evacuation operation, thereby improving safety.

[0037] Fig. 4 is a diagram illustrating the retraction function of one robot 102A of the two robots in Fig. 1. When the gap between the end effectors 108a and 108b is wide during an emergency stop (step S104 in Fig. 2, Yes), if an external force is applied by worker H to one of the robots 102A and 102B, robot 102A, as shown in Fig. 4, the retraction control device 130 retracts only one robot, robot 102A, in the direction of the external force indicated by arrow C (step S108). In this way, if retracting only one robot is sufficient to allow escape, retracting only robot 102A to which the external force is applied allows worker H to reliably escape, thereby improving safety.

[0038] 2, if the evacuation control device 130 determines that one robot to which an external force has been applied is performing a cooperative operation based on the cooperative operation determination result of the cooperation determination device 132 (Yes), the evacuation control device 130 performs the process of step S110. In step S110, the evacuation control device 130 executes a cooperative evacuation operation to evacuate the two robots 102A and 102B while maintaining their relative positions (see FIG. 5).

[0039] Figure 5 is a diagram illustrating the cooperative retreat operation of the two robots 102A and 102B in Figure 1. Figure 5(a) shows a state in which the adjacent robots 102A and 102B are cooperatively operating to grasp a workpiece W with the end effectors 108a and 108b, and a worker H is surrounded by the arms 106a and 106b of the robots 102A and 102B and the workpiece W.

[0040] As shown in FIG. 5(b), when an external force is applied by worker H to one of robots 102A and 102B, robot 102B, the evacuation control device 130 performs a cooperative evacuation operation in which robot 102B is evacuated in the direction of the external force indicated by arrow D, and the other robot 102A, which was operating cooperatively, is moved in the direction indicated by arrow E so as to maintain the relative positional relationship between them.

[0041] Therefore, in the collaborative robot system 100, even when adjacent robots 102A and 102B cooperate to grip the workpiece W, the workpiece W will not be dropped and damaged, and the dropped workpiece W will not collide with the worker H. This improves the safety of the worker H who is trying to escape.

[0042] Furthermore, after the cooperative retraction operation, the arms 106a, 106b of the robots 102A, 102B do not collide with the worker H and maintain an appropriate gap. This ensures that the safety of the worker H is not compromised. In other words, the collaborative robot system 100 not only ensures the safety of the worker H but also prevents the workpiece W from falling by performing the cooperative retraction operation.

[0043] Furthermore, the evacuation control device 130 may perform a cooperative evacuation operation by moving the robots 102A and 102B in the directions indicated by arrows D and E in Figure 5(b) and then lifting the arms 106a and 106b. By performing such a cooperative evacuation operation, the worker H can be reliably allowed to escape even if a wall is located behind the worker H.

[0044] 6 is a flowchart showing the operation of the standby mode in another embodiment of the collaborative robot system 100 of FIG. 1. First, the retraction control device 130 determines whether an external force is applied to only one robot during the standby mode (step S200). Here, when the external force calculation device 114 receives sensor values ​​from both the external force sensors 112a and 112b of the robots 102A and 102B, it outputs two external force values ​​to the retraction control device 130. When the external force calculation device 114 receives a sensor value from only one of the external force sensors 112a and 112b, it outputs one external force value to the retraction control device 130.

[0045] In step S200, if the retraction control device 130 determines that an external force has been applied to one of the robots (Yes), it performs a retraction operation (step S208). In the retraction operation in step S208, the retraction control device 130 executes steps S100 to S110 in the standby mode shown in Fig. 2, performs a separation operation shown in Fig. 3, retracts only one robot 102A shown in Fig. 4, or performs a cooperative retraction operation shown in Fig. 5.

[0046] In step S200, when two external force values ​​are input from the external force calculation device 114, the evacuation control device 130 determines that an external force has been applied to the two robots 102A and 102B (step S200, No), and performs loop processing starting from step S202. In step S202, the evacuation control device 130 determines whether an external force has been applied to each of the two robots 102A and 102B two or more times.

[0047] In step S202, if an external force is applied only once to each of the two robots 102A and 102B (No), the evacuation control device 130 performs a spacing operation to evacuate the robots 102A and 102B in a direction that increases the distance between them (step S204). This allows the worker to escape reliably, improving safety.

[0048] On the other hand, if an external force is applied to each of the robots 102A and 102B two or more times within the predetermined time in step S202 (Yes), the retraction control device 130 stops the robots 102A and 102B (step S206). The term "stop" in step S206 means that, when the robots are already stopped in standby mode, they are maintained in a stopped state without performing any retraction or spacing operation. "When an external force is applied two or more times within a predetermined time" refers to a so-called double tap, triple tap, or the like. By allowing the operator to apply an external force to the robots 102A and 102B and command them to stop, the operator's intention can be communicated to the retraction control device 130, and the operator can command an operation more suited to the situation, thereby further improving safety.

[0049] In the above example, a single tap is used to perform the retreat operation (S208) or the interval operation (S204), and a double tap is used to stop the robot (S206). However, the present invention is not limited to this, and it may be set so that a single tap stops the robot and a double tap initiates the retreat operation. In this way, by changing the behavior of the stop or retreat operation depending on the number of times an external force is applied to a single robot within a specified time, the worker can give the robot appropriate commands. Furthermore, by being able to issue commands to stop the robot in addition to retreating, safety can be improved.

[0050] While the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to such examples. It is clear that those skilled in the art can conceive of various modifications and alterations within the scope of the claims, and it is understood that such modifications and alterations also fall within the technical scope of the present invention. [Industrial Applicability]

[0051] The present invention is applicable to collaborative robot systems with safety features. [Explanation of symbols]

[0052] 100... collaborative robot system, 102A, 102B... collaborative robot, 104... robot control device, 106a, 106b... arm, 108a, 108b... end effector, 110a, 110b... motor, 112a, 112b... external force sensor, 114... external force calculation device, 116... collision detection device, 118... operation determination device, 120, 122... switch, 124... servo control device, 126... robot program storage device, 128... program execution device, 130... evacuation control device, 132... cooperation determination device, 134... operation unit, H... worker, W... work

Claims

1. a plurality of robots each having an external force sensor; a collision detection device that detects, based on an output from the external force sensor, that at least one of the plurality of robots has collided with an object; an operation determination device that switches the operation mode of the robot from an automatic operation mode to a standby mode upon detection by the collision detection device; an evacuation control device that causes the plurality of robots to perform an evacuation operation, a retraction control device for retracting a robot when an external force is applied to the robot during standby mode, and for performing a separation operation to move another robot adjacent to the retracted robot in a direction opposite to the direction of the retracted robot;

2. a plurality of robots each having an external force sensor; a collision detection device that detects, based on an output from the external force sensor, that at least one of the plurality of robots has collided with an object; an operation determination device that switches the operation mode of the robot from an automatic operation mode to a standby mode upon detection by the collision detection device; an evacuation control device that causes the plurality of robots to perform an evacuation operation, The collaborative robot system is characterized in that, when an external force is applied to one robot while in standby mode, the retraction control device retracts the robot and performs cooperative retraction operation by operating other robots that were operating cooperatively with the retracted robot so as to maintain their relative positions.

3. a plurality of robots each having an external force sensor; a collision detection device that detects, based on an output from the external force sensor, that at least one of the plurality of robots has collided with an object; an operation determination device that switches the operation mode of the robot from an automatic operation mode to a standby mode upon detection by the collision detection device; an evacuation control device that causes the plurality of robots to perform an evacuation operation, When an external force is applied to one of the robots during the standby mode, the evacuation control device If the program being executed when the robot collides with the object is a non-cooperative operation, the robot is made to retreat, and a separation operation is performed in which another robot adjacent to the retreated robot is made to move in a direction opposite to the direction of the retreated robot; A collaborative robot system characterized in that, if the program is for cooperative operation, the robot is evacuated and a cooperative evacuation operation is performed in which other robots operating cooperatively are operated so as to maintain their relative positions with the evacuated robot.

4. 4. The collaborative robot system according to claim 1, wherein the retraction control device performs a spacing operation to retract the two adjacent robots to which the external force has been applied in a direction that increases the distance between them when an external force is applied to each of the two adjacent robots once.

5. 4. The collaborative robot system according to claim 1, wherein the evacuation control device maintains the stop of one robot when an external force is applied to the robot multiple times within a predetermined time.

6. 4. The collaborative robot system according to claim 1, wherein the retraction control device performs the separating operation when an external force is applied to one robot multiple times within a predetermined time.

7. 4. The collaborative robot system according to claim 2, wherein the retraction control device performs the cooperative retraction operation when an external force is applied to one robot multiple times within a predetermined time.

Images