Restriction provision for robot control

Abstract

A robot system includes: a robot arranged in a real workspace and having a plurality of drive axes each having a degree of freedom for moving an end effector; a simulation unit configured to set a specified point in a task and virtually execute a simulated posture of the robot at the specified point through simulation based on a robot model indicating the robot; a determination unit configured to calculate a tolerance degree indicating how far the simulated posture is from a limit posture of the robot and determine a constraint condition of at least one of the plurality of drive axes at the specified point based on the calculated tolerance degree; and a robot control unit configured to control the robot based on the constraint condition.

Claims

[1] A robot system (1) comprising: a robot (2) arranged in a real workspace (9) and having a plurality of drive axes, each having a degree of freedom for moving an end effector (2a); a simulation unit (11) configured to set a specified point in a task and virtually execute a simulated posture of the robot (2) at the specified point through a simulation based on a robot model indicating the robot (2); a determination unit (13) configured to calculate a tolerance degree indicating how far the simulated posture is from a limit posture of the robot (2), and to determine a constraint condition of at least one of the plurality of drive axes at the specified point based on the calculated tolerance degree; and a robot control unit (16) configured to control the robot (2) based on the constraint condition. [2] The robot system (1) according to claim 1, wherein the plurality of drive axles includes a redundant axle and wherein the determination unit (13) is configured to determine a position on the redundant axis as a constraint condition. [3] The robot system (1) according to claim 1 or 2, further comprising a (4) sensor configured to detect a real position of a workpiece (8) present in the real work space (9) as a workpiece position, wherein the robot control unit (16) is configured to control the robot (2) to machine the workpiece (8) based on the constraint condition and the workpiece position detected by the sensor (4). [4] The robot system (1) according to claim 3, further comprising an adjustment unit (14) configured to adjust the set point based on the workpiece position detected by the sensor (4), wherein the robot control unit (16) is configured to control the robot (2) to machine the workpiece (8) based on the adjusted set point. [5] The robot system (1) according to claim 4, further comprising a path generation unit (15) configured to generate a path for moving the end effector (2a) to the adjusted predetermined point. [6] The robot system (1) according to any one of claims 1 to 5, further comprising a task storage unit (12) configured to store a task for machining a workpiece (8), wherein the simulation unit (11) is configured to: a starting position, ie a position at which the end effector (2a) in the task begins to act on the workpiece (8), is set as a fixed point; and a work scene in which the robot positions the end effector (2a) by the simulated posture at the start position in order to machine the workpiece (8), virtually executes through the simulation, and wherein the determination unit (13) is configured to determine the restriction condition for the action of the end effector (2a) on the workpiece (8). [7] The robot system (1) according to claim 6, wherein the task storage unit (12) is configured to store two or more of the tasks, and wherein the simulation unit (11) is configured to: sets the specified point for each of the two or more tasks; and virtually executes the work scene including the two or more tasks in a state in which a position of each of the at least one of the plurality of drive axes is fixed at a common position that is the same position among the two or more tasks, and wherein the determination unit (13) is configured to determine the constraint condition common to the two or more tasks based on the degree of tolerance in each of the two or more tasks. [8] The robot system (1) according to claim 2, wherein the simulation unit (11) is configured to virtually execute the simulated posture for each of the plurality of candidate positions fixed on the redundant axis, and wherein the determination unit (13) is configured to: calculates the tolerance level for each of the plurality of candidate positions based on the simulated posture for each of the plurality of candidate positions and the boundary posture; and a candidate position among the plurality of candidate positions is determined as a constraint condition based on the tolerance degree for each of the plurality of candidate positions. [9] A robot control method executable by a robot control system (10) comprising at least one processor (161) controlling a robot (2) arranged in a real workspace (9) and having a plurality of drive axes, each of which has a degree of freedom for moving an end effector (2a), the method comprising: setting (S11) a fixed point in a task; virtually executing (S13) a simulated posture of the robot (2) at the specified point by a simulation based on a robot model indicating the robot (2); calculating (S14) a tolerance level indicating how far the simulated posture is from a limit posture of the robot (2); determining (S15) a constraint condition of at least one of the plurality of drive axes at the specified point based on the calculated tolerance level; and controlling (S19) the robot (2) based on the constraint condition. [10] A robot control program that causes a computer (100) to act as a robot control system (10) to control a robot (2) arranged in a real workspace (9) and having a plurality of drive axes, each having a degree of freedom for moving an end effector (2a), the robot control program comprising instructions that, when the program is executed by the computer (100), cause the computer (100) to perform the following: setting (S11) a fixed point in a task; virtually executing (S13) a simulated posture of the robot (2) at the specified point by a simulation based on a robot model indicating the robot (2); calculating (S14) a tolerance level indicating how far the simulated posture is from a limit posture of the robot (2); determining (S15) a constraint condition of at least one of the plurality of drive axes at the specified point based on the calculated tolerance level; and controlling (S19) the robot (2) based on the constraint condition.

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