Control device for mobile robot

Patent metadata

Field	Value
Publication number	US-9862095-B2
Application number	US-201514802344-A
Country	US
Kind code	B2
Filing date	Jul 17, 2015
Priority date	Sep 24, 2014
Publication date	Jan 9, 2018
Grant date	Jan 9, 2018

Abstract

The present invention provides a control device for a mobile robot. While a mobile robot 1 is in a predetermined motion state, if a load evaluation amount, which is either the magnitude of a load detected on a particular joint or an estimated temperature value of a joint actuator for driving the joint, exceeds a predetermined threshold value, then a desired displacement amount of each joint of the mobile robot 1 is determined with a requirement that the load evaluation amount remains to be the threshold value or less, and the joint actuator is controlled on the basis of the determined desired displacement amount.

First claim

What is claimed is:

1. A control device for a mobile robot having a base body, a plurality of joints, a movable link connected to the base body such that the movable link moves with respect to the base body by a motion of one or more joints among the plurality of the joints, and a joint actuator that drives each of the joints, the control device comprising at least one processor and a memory, the memory having stored thereon a program which, when executed by the at least one processor, causes the control device to function as a plurality of units, comprising:
a joint load detecting unit that detects a load on each joint of the mobile robot; and
a joint control unit which discriminates whether a load evaluation amount exceeds a predetermined threshold value in a predetermined motion state of the mobile robot, and, when the joint control unit discriminates that the load evaluation amount exceeds the predetermined threshold value in the predetermined motion state of the mobile robot, determines a desired displacement amount of each joint of the mobile robot that satisfies a requirement that the load evaluation amount remains the predetermined threshold value or less, and the joint control unit controls the joint actuator for driving each joint of the mobile robot based on the desired displacement amount,
wherein the load evaluation amount is either a magnitude of the load detected on a particular joint of the mobile robot by the joint load detecting unit or an estimated temperature value of the joint actuator for driving the particular joint in a predetermined time obtained based on the magnitude of the load detected on the particular joint of the mobile robot by the joint load detecting unit, and
wherein the predetermined motion state is a motion state including a motion according to a motion command.

2. The control device for the mobile robot according to claim 1 ,
wherein the mobile robot has a plurality of movable links, which include the movable link, connected to the base body such that each of the plurality of movable links moves with respect to the base body by the motion of one or more joints among the plurality of the joints driven by the joint actuator, and
wherein the predetermined motion state is a state in which the motion of at least a contact movable link, which is at least one of the plurality of movable links which is brought into contact with an external object to be subjected to a contact reaction force against a gravitational force acting on the mobile robot, is at a halt.

3. The control device for the mobile robot according to claim 2 ,
wherein the joint control unit is configured to determine, as the desired displacement amount of each joint of the mobile robot, the desired displacement amount which can be attained while holding the contact movable link in contact with the external object and which makes it possible to satisfy the requirement in the state in which the motion of the contact movable link is at a halt at the desired displacement amount, and to control the joint actuator for driving each joint so as to change an actual displacement amount of each joint of the mobile robot to the determined desired displacement amount.

4. The control device for the mobile robot according to claim 1 ,
wherein the joint control unit is configured to determine the desired displacement amount of each joint of the mobile robot which makes it possible to satisfy the requirement under a constraint condition related to a position of a contact portion to be brought in contact with an external object during the predetermined motion state among individual portions of the mobile robot, a contact reaction force acting on the contact portion, and a position of the center of gravity of the mobile robot.

5. The control device for the mobile robot according to claim 4 ,
wherein the constraint condition related to the position of the contact portion is a constraint condition that restricts a desired position of the contact portion to an actual position of the contact portion, the constraint condition related to the contact reaction force is a constraint condition that restricts a moment acting on the mobile robot due to the contact reaction force, and the constraint condition related to the position of the center of gravity is a constraint condition that restricts a positional relationship between the position of the center of gravity and the contact portion.

6. The control device for the mobile robot according to claim 1 ,
wherein the joint control unit is configured to control the joint actuator for driving each joint such that, in the case where an actual displacement amount of each joint of the mobile robot is changed to the determined desired displacement amount, a magnitude of a temporal change rate of the displacement amount of each joint in a period immediately after a start of a transition and a period immediately before an end thereof is smaller than that in a period between the period immediately after the start of the transition and the period immediately before the end thereof.

Assignees

• Honda Motor Co Ltd

Inventors

• Takagi Yutaka
• Tanaka Chiaki

Classifications

• B62D57/032

  with alternately or sequentially lifted supporting base and legs; with alternately or sequentially lifted feet or skid (B62D57/024 takes precedence) · CPC title

• G05B2219/42289

  Avoid overload servo motor, actuator limit servo torque · CPC title

• G05B2219/42282

  If displacement rate of actuator exceeds limit, lower it · CPC title

• G05B19/4063

  Monitoring general control system (G05B19/4062 takes precedence) · CPC title

• Y10S901/01

  Mobile robot · CPC title