Master-slave manipulator control

• US 5,053,975 A
• Filed: 06/08/1989
• Issued: 10/01/1991
• Est. Priority Date: 06/10/1988
• Status: Expired due to Term

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Aoki, Tatsu, Takarada, Shinichi, Yamamoto, Hiroshi, Iwamoto, Taro, Nakajima, Kichio, Tsuchihashi, Akira
• Primary Examiner(s): MacDonald, Allen R.
• Assistant Examiner(s): Davis, George
• Application Number:
  US07/363,071
• Time in Patent Office: 845 Days
• Field of Search: 364/513, 364/191, 901/2, 901/3, 901/4, 901/14, 901/15, 901/19, 901/27, 901/28
• US Class Current: 700/264
• CPC Class Codes: G05B 19/427 Teaching successive positions by tracking the position of a joystick or handle to control the positioning servo of the tool head, master-slave control G05B19/423 takes precedence

Abstract

After positional information of the master arm is transformed into first generalized world coordinates corresponding to positional information representing a calculated position of the slave arm, when a signal instructing an interruption of the associated operation between the master arm and the slave arm is received and then the positional relationships between the master arm and the slave arm connected thereto by use of an imaging device are updated, the first generalized world coordinates are transformed into the second generalized world coordinates based on the new positional relationships so as to restart the associated operation therebetween. The optimal control of the manipulator is conducted through matrix operations related to the change-over between imaging devices, the reset operation conducted in an area of the movable range of the master arm, and the alteration of the ratio between the movements of the associated operation.

Claims

1. A manipulator control system comprising:

(a) a master arm including a plurality of first links sequentially connected by joints;

(b) a slave arm including a plurality of second links sequentially connected by joints;

(c) an operational panel having means for generating operating signals for adjusting the operability of said master arm;

(d) a plurality of controllers for effecting movement control of said slave arm by following a movement of said master arm;

(e) first transform means connected to said controllers for transforming information of positions of said master arm into first generalized world coordinates associated with instructive positional information of said slave arm based on an initial relative positional relationship between said master arm and said slave arm;

(f) second transform means for receiving the operating signals of said operation panel and the first generalized world coordinates supplied form said first transform means so as to transform the first generalized world coordinates into second generalized world coordinates for selectively establishing a change in a relative positional relationship between said master arm and said slave arm; and

,

(g) inverse transform means for receiving as an input the second generalized world coordinates so as to determine coordinate values of the joints of the slave arm.

2. The manipulator control system according to claim 1 further comprising:

a plurality of image input devices each for obtaining an image of said slave arm; and

change-over means for selecting an arbitrary one of said plurality of image input devices wherein

based on information about a direction with respect to said slave arm, said image input device is selected by use of said change-over means, and said second transform means transforms the first generalized world coordinates into the second generalized world coordinates.

3. A manipulator control system according to claim 1 wherein said controllers include:

control means for stopping the movement of said slave arm in response to a signal instructing an interruption of an operation of said slave arm following said master arm;

means for effecting a coordinate transformation to correct an amount of the movement of said slave arm in association with an amount of a positional shift achieved by said master arm while said slave arm is in a stopped state; and

control means for restarting an operation of said slave arm in response to a signal indicating a restart of the operation of said slave arm following said master arm.

4. The manipulator control system according to claim 1 further comprising:

joy stick means disposed together with said master arm for generating an operation positional signal;

control means for effecting control in response to a signal to select either one of said master arm and said joy stick means so as to cause the movement of said slave arm to follow either one of the movements of said master arm and said joy stick means; and

means connected to said control means for effecting a transformation of the first generalize world coordinates in response to the selection signal.

5. A method of controlling a manipulator in a master/slave apparatus having an operation arm and a manipulator operating in association with a movement of the operation arm comprising the following steps of:

setting an origin to establish a one-to-one correspondence between the operation arm and the manipulator so as to transform positional information of the operation arm and the manipulator into generalized world coordinates;

effecting a first coordinate transformation to match an origin of a generalized world coordinate with an origin of the operation arm and an origin of the manipulator to effect a coordinate transformation to attain instruction values of each axis so as to operate the manipulator;

effecting a second coordinate transformation to transform the first generalized world coordinates into second generalized world coordinates by an outside signal indicating a change in a positional effect of the operation arm to the manipulator and keeping the one-to-one correspondence between the operation arm and the manipulator; and

controlling the manipulator in response to the second generalized world coordinates.

6. A method of controlling a manipulator according to claim 5 wherein said effecting a second coordinate transformation further includes a step for achieving a display of the second generalized world coordinates to conduct an animation.

7. The manipulator control method according to claim 6 wherein said step for achieving a display of the second generalized world coordinate to conduct an animation further includes a step for superimposing the animation onto a real image obtained through an image input device.

8. A method of controlling a manipulator according to claim 5 wherein said step of effecting a second coordinate transformation further includes a step operative to effect a display on an image display by achieving a change-over between two or more image input devices for transforming the first generalized world coordinates into the second generalized world coordinates in association with a direction of an arrangement orientation of each of the image input devices.

9. A method of controlling a manipulator according to claim 5 wherein the first generalized world coordinates are transformed into the second generalized world coordinates depending on a zooming ratio of an image input device.

10. A manipulator control method according to claim 5 further including a step for integrating with respect to time a velocity instruction issued from each said operation arm to produce a virtual position information.