CONTROL APPARATUS AND CONTROL METHOD FOR ROBOT, ROBOT, AND CONTROL PROGRAM THEREFOR

• US 20130006422A1
• Filed: 09/12/2012
• Published: 01/03/2013
• Est. Priority Date: 12/08/2010
• Status: Active Grant

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: KOMATSU, Mayumi
• Granted Patent: US 8,509,950 B2
• Time in Patent Office: Days
• US Class Current: 700/258
• CPC Class Codes: B25J 9/1638 compensation for arm bending/inertia, pay load weight/inertia
• CPC Class Codes: B25J 9/1674 characterised by safety, monitoring, diagnostic

Abstract

There are included a desired joint torque output limiting unit for limiting operations of a desired joint torque output unit and a limit cancellation unit for canceling the limitation by the output limiting unit. An actuator of a joint of a robot is controlled in accordance with modified desired joint torque outputted from the output limiting unit, so that the robot can be controlled to be kept stopped even upon switching between dynamics parameters.

Claims

1. A control apparatus for a robot comprising a joint, the control apparatus comprising:

a dynamics parameter acquisition unit that acquires a plurality of dynamics parameters for the robot and an object gripped by the robot;

a desired joint torque output unit that outputs, as a desired joint torque, a desired value of torque of the joint of the robot;

a dynamics parameter switching unit that switches between the plurality of dynamics parameters acquired by the dynamics parameter acquisition unit;

a desired joint torque output limiting unit that limits an output of the desired joint torque from the desired joint torque output unit after the dynamics parameter switching unit switches between the dynamics parameters; and

a limit cancellation unit that cancels a limitation by the desired joint torque output limiting unit.

2. The control apparatus for a robot according to claim 1, wherein, immediately after the dynamics parameters are switched, the desired joint torque output limiting unit maintains the output of the desired joint torque from the desired joint torque output unit immediately before the dynamics parameters are switched.

3. The control apparatus for a robot according to claim 1, further comprising:

a robot shift detection unit that detects shift of the robot;

wherein

the desired joint torque output limiting unit maintains the desired joint torque outputted from the desired joint torque output unit at a moment when the robot shift detection unit detects shift of the robot.

4. The control apparatus for a robot according to claim 1, further comprising:

a desired angle generation unit that generates and outputs a desired joint angle vector that is used to achieve a desired operation of the robot;

wherein

the desired joint angle vector outputted from the desired angle generation unit is used when the desired joint torque output unit outputs the desired value of the torque of the joint of the robot as the desired joint torque, and the limit cancellation unit cancels the limitation on the output of the desired joint torque from the desired joint torque output unit when determined that a desired position of the robot is changed in accordance with the desired joint angle vector outputted from the desired angle generation unit.

5. The control apparatus for a robot according to claim 1, wherein

the limit cancellation unit further comprises a force detection unit that detects force externally applied to the robot, and

the force detection unit cancels the limitation on the output of the desired joint torque from the desired joint torque output unit when the force detection unit detects a force of a magnitude equal to or more than a threshold.

6. The control apparatus for a robot according to claim 1, wherein the limitation on the output by the desired joint torque output limiting unit is not applied to a joint moving in a vertical direction in the robot.

7. The control apparatus for a robot according to claim 1, wherein

the dynamics parameter switching unit comprises an object grip detection unit that detects that the object is gripped by the robot, and

the dynamics parameter switching unit switches between the dynamics parameters after the object grip detection unit detects that the object is gripped.

8. A robot comprising:

the control apparatus according to claim 1 for the robot;

a robot arm including the joint; and

a hand that is supported at a distal end of the robot arm and is capable of gripping the object.

9. A method of controlling a robot including a joint, the method comprising:

acquiring, by a dynamics parameter acquisition unit, a plurality of dynamics parameters for the robot and an object gripped by the robot;

outputting, from a desired joint torque output unit, a desired value of torque of the joint of the robot as a desired joint torque;

switching, by a dynamics parameter switching unit, between the plurality of the dynamics parameters acquired by the dynamics parameter acquisition unit;

limiting, by a desired joint torque output limiting unit, the output of the desired joint torque from the desired joint torque output unit after the dynamics parameter switching unit switches between the dynamics parameters; and

canceling, by a limit cancellation unit, the limitation by the desired joint torque output limiting unit.

10. A control program for a control apparatus of a robot including a joint, the control program causing a computer to function as:

a dynamics parameter acquisition unit that acquires a plurality of dynamics parameters for the robot and an object gripped by the robot;

a desired joint torque output unit that outputs a desired value of torque of the joint of the robot as a desired joint torque;

a dynamics parameter switching unit that switches between the plurality of dynamics parameters acquired by the dynamics parameter acquisition unit;

a desired joint torque output limiting unit that limits the output of the desired joint torque from the desired joint torque output unit after the dynamics parameter switching unit switches between the dynamics parameters; and

a limit cancellation unit that cancels the limitation by the desired joint torque output limiting unit.