Actuator Control Device, Actuator Control Method, Actuator, Robot Apparatus, and Computer Program

• US 20090272585A1
• Filed: 04/29/2009
• Published: 11/05/2009
• Est. Priority Date: 05/01/2008
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: NAGASAKA, Kenichiro
• Granted Patent: US 8,340,822 B2
• Time in Patent Office: Days
• US Class Current: 180/8.600
• CPC Class Codes: B25J 9/1633 compliant, force, torque control, e.g. combined with position control
• CPC Class Codes: G05B 2219/39319 Force control, force as reference, active compliance
• CPC Class Codes: G05B 2219/39355 Observer, disturbance observer
• CPC Class Codes: Y10T 74/20317 including electric motor

Abstract

There is provided an actuator control device for force-controlling a joint driving actuator according to a commanded joint force command value τ_a. The actuator control device includes a joint value detecting means for detecting a joint value q at an output stage of the actuator, an action force detecting means for detecting an action force τ_e in a joint driving direction at the output stage of the actuator, and a driving force determining means for determining an instructed driving force τ to the actuator, on the basis of an ideal response model of the actuator which specifies the relationship of a joint value acceleration target value achieved as the actuator responds ideally when the joint force command value τ_a, the action force τ_e, and a joint value velocity obtained by time-differentiating the joint value q are given.

Claims

1. An actuator control device for force-controlling a joint driving actuator according to a commanded joint force command value τ

_a, the actuator control device comprising;

a joint value detecting means for detecting a joint value q at an output stage of the actuator;

an action force detecting means for detecting an action force τ

_e in a joint driving direction at the output stage of the actuator; and

a driving force determining means for determining an instructed driving force τ

to the actuator, on the basis of an ideal response model of the actuator which specifies the relationship of a joint value acceleration target value achieved as the actuator responds ideally when the joint force command value τ

_a, the action force τ

_e, and a joint value velocity obtained by time-differentiating the joint value q are given.

2. The actuator control device according to claim 1,

wherein the ideal response model of the actuator includes an virtual inertia or an virtual viscous resistance coefficient υ

_a which acts according to the magnitude of the joint value velocity obtained by time-differentiating the joint value q.

3. The actuator control device according to claim 1,

wherein the driving force determining means applies a disturbance observer to determine the driving force τ

of the actuator.

4. The actuator control device according to claim 1,

wherein the disturbance observer estimates a driving force which has acted on the joint on the basis of the joint value velocity obtained by time-differentiating the joint value q detected by the joint value detecting means when the joint actuator is driven by the driving force τ

determined by the driving force determining means, and subtracts the estimated driving force from the driving force τ

to calculate a disturbance joint force τ

_d.

5. The actuator control device according to claim 4,

wherein the driving force determining means corrects a joint force target value τ

^ref, which is based on the joint value acceleration target value obtained from the ideal response model, by the disturbance joint force τ

_d obtained by the disturbance observer in a previous control cycle, and determines the instructed driving force τ

in a current control cycle.

6. An actuator control method for force-controlling a joint driving actuator according to a commanded joint force command value τ

_a, the method comprising the steps of;

obtaining a joint value q at an output stage of the actuator;

obtaining an action force τ

_e in a joint driving direction at the output stage of the actuator; and

determining an instructed driving force τ

to the actuator, on the basis of an ideal response model of the actuator which specifies the relationship of a joint value acceleration target value achieved as the actuator responds ideally when the joint force command value τ

_a, the action force τ

_e, and a joint value velocity obtained by time-differentiating the joint value q are given.

7. The actuator control method according to claim 6,

wherein the ideal response model of the actuator includes an virtual inertia or an virtual viscous resistance coefficient υ

_a which acts according to the magnitude of the joint value velocity obtained by time-differentiating the joint value q.

8. The actuator control method according to claim 6,

wherein a disturbance observer is applied to determine the driving force τ

of the actuator in the driving force determining step.

9. The actuator control method according to claim 6,

wherein the disturbance observer estimates a driving force which has acted on the joint on the basis of the joint value velocity obtained by time-differentiating the joint value q obtained in the joint value obtaining step when the joint actuator is driven by the driving force τ

determined in the driving force determining step, and subtracts the estimated driving force from the driving force τ

to calculate a disturbance joint force τ

_d.

10. The actuator control device according to claim 9,

wherein, in the driving force determining step, a joint force target value τ

^ref, which is based on the joint value acceleration target value obtained from the ideal response model, is corrected by the disturbance joint force τ

_d obtained by the disturbance observer in a previous control cycle, and the instructed driving force τ

in a current control cycle is determined.

11. An actuator comprising:

a motor which generates a rotary torque;

a motor driver which drives the motor;

a reducer which converts a rotary force of the motor into a sufficient generation force;

a encoder which measures a joint angle q at an output shaft of the reducer;

a torque sensor which detects an external torque τ

_e of the motor at the output shaft of a reducer; and

a control unit which determines an instructed torque τ

on the basis of an ideal response model of the actuator which specifies the relationship of a joint value acceleration target value achieved as the actuator responds ideally when the torque command value τ

_a, the external torque τ

_e, and a joint value velocity obtained by time-differentiating the joint value q are given, and which converts and outputs the determined torque into a control signal for a motor driver.

12. The actuator according to claim 11,

wherein the ideal response model includes an virtual inertia or an virtual viscous resistance coefficient υ

_a which acts according to the magnitude of the joint angular velocity obtained by time-differentiating the joint value q measured by the encoder.

13. The actuator according to claim 11,

wherein, the control unit includes a disturbance observer estimates a torque, which has acted on the joint based on a joint angular velocity obtained by time-differentiating the joint angle q detected by the encoder, when the actuator is driven by the joint torque τ

, and subtracts the estimated torque from the instructed torque τ

to calculate a disturbance torque τ

_d, and corrects a joint force target value τ

^ref, which is based on the joint value acceleration target value obtained from the ideal response model, by the disturbance joint force τ

_d obtained by the disturbance observer in a previous control cycle, and determines the instructed driving force τ

in a current control cycle.

14. A robot apparatus comprising a link structure constructed by connecting a plurality of rigid body links, and joint actuators which drive joints which connect between the links, and at least some joint actuators are constituted by the actuators according to claim 11.

15. A computer program described in a computer readable format so as to execute processing for force-controlling a joint driving actuator according to a commanded joint force command value τ

_a on a computer,

the program causing the computer to function as;

a joint value detecting means for detecting a joint value q at an output stage of the actuator;

an action force detecting means for detecting an action force τ

_e in a joint driving direction at the output stage of the actuator; and

a driving force determining means for determining an instructed driving force τ

to the actuator, on the basis of an ideal response model of the actuator which specifies the relationship of a joint value acceleration target value achieved as the actuator responds ideally when the joint force command value τ

_a, the action force τ

_e, and a joint value velocity obtained by time-differentiating the joint value q are given.

16. An actuator control device for force-controlling a joint driving actuator according to a commanded joint force command value τ

_a, the actuator control device comprising;

a joint value detector detecting a joint value q at an output stage of the actuator;

an action force detector configured to detect an action force τ

_e in a joint driving direction at the output stage of the actuator; and

a driving force determining unit configured to determine an instructed driving force τ

to the actuator, on the basis of an ideal response model of the actuator which specifies the relationship of a joint value acceleration target value achieved as the actuator responds ideally when the joint force command value τ

_a, the action force τ

_e, and a joint value velocity obtained by time-differentiating the joint value q are given.