Control device for robot

• US 8,532,824 B2
• Filed: 12/27/2010
• Issued: 09/10/2013
• Est. Priority Date: 12/28/2009
• Status: Active Grant

• Current Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Original Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Inventors: Orita, Atsuo
• Primary Examiner(s): Tran, Khoi
• Assistant Examiner(s): Kiswanto, Nicholas
• Application Number:
  US12/978,915
• Publication Number:
  US 20110160907A1
• Time in Patent Office: 988 Days
• Field of Search: 700/245, 700/247, 700/250, 700/251, 700/260, 700/261, 700/262, 700/263
• US Class Current: 700/260
• CPC Class Codes: B25J 9/1607 Calculation of inertia, jacobian matrixes and inverses
• CPC Class Codes: B62D 57/032 with alternately or sequentially lifted supporting base and legs; with alternately or sequentially lifted feet or skid B62D57/024 takes precedence

Abstract

A control device for a robot determines, as a desired driving force to be imparted to a joint, a component value corresponding to the displacement amount of each joint out of a desired generalized force vector τcmd that satisfies the relationship indicated by expression 01 given below by using basic parameter group of M, N, and G, Jacobian matrixes Jc and Js, a desired value ↑C of the motion acceleration of a contact portion representative element representing a motion of a contact portion of a robot 1, generalized variable observation information, and a desired value ↑S′ of a first-order differential value of a predetermine type of state amount, and then controls the operation of an actuator of the robot 1 on the basis of the determined desired driving force.
S′+(Js*M⁻¹*Tc−Js′)*q′=(Js*M⁻¹*Pc)*(τcmd−τcmpn)  Expression 01

Claims

1. A control device for a robot configured to determine a desired driving force to be imparted to each joint of a robot, which has a plurality of links interconnected through joints and actuators which drive the joints, and to control the operation of each of the actuators on the basis of the determined desired driving force in the case where a motion of the robot is effected while causing at least one or more contact portion of the robot to come in contact with an external world of the robot, the control device comprising:

a basic parameter group calculating unit which calculates a basic parameter group constituted of an inertia matrix for converting the second-order differential value of a generalized variable vector of the robot, which includes at least the displacement amount of each joint of the robot as a component, into a generalized force vector, and a gravity-dependent generalized force vector value, which is the value of a generalized force vector produced by the gravitational force acting on each link of the robot, or a basic parameter group constituted of the inertia matrix, the gravity-dependent generalized force vector, and a centrifugal force/Coriolis force-dependent generalized force vector value, which is the value of a generalized force vector generated by a centrifugal force and a Coriolis force acting on each link of the robot, on the basis of generalized variable observation information, which includes at least the observed value of an actual displacement amount of each joint of the robot;

a contact portion Jacobian matrix calculating unit which receives contact state information indicating the contact state of the one or more contact portions and the generalized variable observation information and calculates a contact portion Jacobian matrix, which is a Jacobian matrix expressing a relationship between the motion velocity of a predetermined contact portion representative element set as an element representing the motion of the one or more contact portions in contact with the external world and a first-order differential value of the generalized variable vector on the basis of at least the received contact state information and generalized variable observation information;

a state amount Jacobian matrix calculating unit which receives the generalized variable observation information and calculates a state amount Jacobian matrix, which is a Jacobian matrix expressing a relationship between a predetermined type of state amount having a value dependent upon the value of the generalized variable vector and the first-order differential value of the generalized variable vector on the basis of at least the received generalized variable observation information;

a desired driving force determining unit which receives the basic parameter group, the contact portion Jacobian matrix and the state amount Jacobian matrix, which have been calculated, a desired value of a contact portion representative element motion acceleration, which is the desired value of the motion acceleration of the contact portion representative element, the generalized variable observation information, and the desired value of the first-order differential value of the predetermined type of state amount, uses the received data to calculate a component value corresponding to the displacement amount of each joint in a desired generalized force vector τ

cmd, which is a target of a generalized force vector that satisfies the relationship of expression 01 given below, and determines the calculated component value as a desired driving force to be imparted to the joint; and

an actuator control unit which controls the operation of the actuator on the basis of at least the determined desired driving force;

S′

+(Js*M<sup>−

1</sup>*Tc−

Js′

)*q′

=(Js*M<sup>−

1</sup>*Pc)*(τ

cmd−

τ

cmpn) 

 

Expression 01

where

q;

generalized variable vector

q′

;

observed value of first-order differential value of q (=dq/dt)

S;

state amount

S′

;

desired value of first-order differential value of S (=dS/dt)

M;

inertia matrix

τ

cmpn;

vector defined by τ

cmpn≡

(N+G)−

Pc<sup>−

1</sup>*Cc or τ

cmpn≡

G−

Pc<sup>−

1</sup>*Cc

G;

gravity-dependent generalized force vector value

N;

centrifugal force/Coriolis force-dependent generalized force vector value

Pc;

matrix defined by Pc≡

I−

Jc^T*(Jc#)^T

I;

unit matrix

Jc;

contact portion Jacobian matrix

Jc#;

matrix defined by Jc#≡

(M<sup>−

1</sup>)^T*Jc^T*Rc^T

Rc;

matrix defined by Rc≡

((Jc*M<sup>−

1</sup>*Jc^T)<sup>−

1</sup>)^T

Cc;

vector defined by Cc≡

−

Jc^T*Rc*C

C;

desired value of contact portion representative element motion acceleration (scalar or vector)

Tc;

matrix defined by Tc≡

−

Jc^T*Rc*Jc′

Jc′

;

matrix obtained by subjecting Jc to first-order differentiation (=dJc/dt)

Js;

state amount Jacobian matrix

Js′

;

matrix obtained by subjecting Js to first-order differentiation (=dJs/dt).

2. The control device for a robot according to claim 1,

wherein the robot is a bipedal mobile robot that travels on a floor surface by carrying out a motion in which the distal portions of two leg links alternately come in contact with the floor surface, and

the contact portion representative element is an element, the position and posture of which exhibit springy displacements based on a total floor reaction force, which is the resultant force of floor reaction forces acting on the two individual leg links, and also an element in which the springy displacement amounts of the position and posture of the contact portion representative element are such that the springy displacement amounts of the position and posture of the distal portion of a first leg link caused by a floor reaction force acting on the first leg link out of the two leg links and the springy displacement amounts of the position and posture of the distal portion of a second leg link caused by a floor reaction force acting on the second leg link out of the two leg links have a relationship denoted by expression 02 given below, and

the contact portion Jacobian matrix calculating unit calculates the contact portion Jacobian matrix Jc by calculating the right side of expression 03 given below:

Xcc=r at*A1*X1+(1−

r at)*A2*X2 

 

Expression 02

Jc=r at*A1*J1+(1−

r at)*A2*J2 

 

Expression 03

where

Xcc;

vector, the components of which are the springy displacement amounts of the position and posture of a contact portion representative element

r at;

coefficient set according to contact state information such that r at=0 in a state wherein only the first leg link is in contact with the ground, r at=1 in a state wherein only the second leg link is in contact with the ground, or r at continuously changes in a range defined by 0≦

r at≦

1 in a state wherein both the first leg link and the second leg link are in contact with the ground

X1;

vector, the components of which are the springy displacement amounts of the position and posture of the distal portion of the first leg link caused by a floor reaction force acting on the first leg link

X2;

vector, the components of which are the springy displacement amounts of the position and posture of the distal portion of the second leg link caused by a floor reaction force acting on the second leg link

A1;

matrix for converting a first floor reaction force vector constituted of a translational force component and a moment component of a floor reaction force acting on the first leg link into a floor reaction force vector acting on the contact portion representative element

A2;

matrix for converting a second floor reaction force vector constituted of a translational force component and a moment component of a floor reaction force acting on the second leg link into a floor reaction force vector acting on the contact portion representative element

J1;

Jacobian matrix expressing the relationship between a first-order differential value X1′

of X1 (=dX1/dt) and a first-order differential value q′

of a generalized variable vector q by X1′

=J1*q′

J2;

Jacobian matrix expressing the relationship between a first-order differential value X2′

of X2 (=dX2/dt) and a first-order differential value q′

of a generalized variable vector q by X2′

=J2*q′

.

3. The control device for a robot according to claim 1,

wherein the actuator control unit comprises a contact portion external force desired value determining unit which determines a contact portion external force desired value as an estimated value of an external force acting on the contact portion by carrying out processing of inverse dynamics calculation, using the desired driving force and the contact portion motion acceleration desired value, which have been determined, in the case where it is assumed that a driving force to be actually imparted to each joint of the robot coincides with the determined desired driving force and the actual motion acceleration of the contact portion representative element coincides with the desired value of the contact portion representative element motion acceleration, and a driving force correction amount calculating unit which determines a correction amount of the desired driving force according to a feedback control law such that a difference between the contact portion external force desired value and an observed value of an external force actually acting on the contact portion is converged to zero, wherein the operation of the actuator is controlled on the basis of the desired driving force that has been corrected using the correction amount.

4. The control unit for a robot according to claim 2,

wherein the actuator control unit comprises a contact portion external force desired value determining unit which determines a contact portion external force desired value as an estimated value of an external force acting on the contact portion by carrying out processing of inverse dynamics calculation, using the desired driving force and the contact portion motion acceleration desired value, which have been determined, in the case where it is assumed that a driving force to be actually imparted to each joint of the robot coincides with the determined desired driving force and the actual motion acceleration of the contact portion representative element coincides with the desired value of the contact portion representative element motion acceleration, and a driving force correction amount calculating unit which determines a correction amount of the desired driving force according to a feedback control law such that a difference between the contact portion external force desired value and an observed value of an external force actually acting on the contact portion is converged to zero, wherein the operation of the actuator is controlled on the basis of the desired driving force that has been corrected using the correction amount.