Master/slave manipulator and control method therefor

• US 5,949,686 A
• Filed: 03/20/1997
• Issued: 09/07/1999
• Est. Priority Date: 09/21/1994
• Status: Expired due to Term

• Current Assignee: Komatsu Ltd.
• Original Assignee: Komatsu Ltd.
• Inventors: Okamura, Kenji, Yoshinada, Hiroshi, Yanagi, Kunikazu
• Primary Examiner(s): Gordon, Paul P.
• Application Number:
  US08/809,393
• Time in Patent Office: 901 Days
• Field of Search: 364/478.01, 318/568.11, 318/568.19, 414/909, 395/95, 395/97, 901/6
• US Class Current: 700/213
• CPC Class Codes: B25J 3/04 involving servo mechanisms servo-actuated heads B25J15/02
• CPC Class Codes: B25J 9/1689 Teleoperation
• CPC Class Codes: G05B 2219/40401 Convert workspace of master to workspace of slave
• CPC Class Codes: G05B 2219/40405 Master slave position control
• CPC Class Codes: G05B 2219/45012 Excavator
• CPC Class Codes: G05B 2219/45058 Grinding, polishing robot

Abstract

The present invention relates to a master/slave manipulator and a method for controlling the same, in which a large working area and good controllability can be provided and a corresponding position shift and an enlargement ratio change can also be attained. To this end, a plurality of representing points are set on and inside a closed surface (A1) of an operating area (A) of one manipulator, while a plurality of target points corresponding to the plurality of representing points are set on and inside a closed surface (B1) of a working area (B) of the other manipulator. Working amounts (β1, β2, θ1, θ2) when the leading ends (11, 12) of the one manipulator and the other manipulator respectively reach the plurality of representing points and the plurality of target points, and a corresponding relationship between the working amounts of the two manipulators are obtained; and when the slave (2) is to be operated, the working amounts (β1, β2) of the master (1) are converted into working amounts (θ1, θ2) of the slave (2) to thereby operate the slave (2).

Claims

1. A method for controlling master/slave manipulators in which an operating area of a leading end of a master manipulator and an operating area of a leading end of a slave manipulator are not similar to each other, said method comprising the steps of:

(1) setting a plurality of representing points on a first closed surface which is a limit surface of an operating area of a first one of said master manipulator and said slave manipulator;

(2) setting a plurality of target points, to respectively correspond to the plurality of representing points set in said step (1), on a second closed surface which is a limit surface of an operating area of a second one of said master manipulator and said slave manipulator;

(3) setting a plurality of representing points inside the operating area of said first one;

(4) setting a plurality of target points, to respectively correspond to the plurality of representing points set in said step (3), inside the operating area of said second one;

(5) obtaining working amounts of respective degrees of freedom of said first one when the leading end of said first one reaches each of the respective plurality of representing points set in said steps (1) and (3), while obtaining working amounts of respective degrees of freedom of said second one when the leading end of said second one reaches the corresponding respective plurality of target points set in steps (2) and (4);

(6) obtaining a corresponding relationship between a pair of working amounts of said first one, obtained in step (5), and a pair of working amounts of said second one, obtained in step (5); and

(7) when said slave manipulator is to be operated by operating said master manipulator, converting working amounts of the master manipulator, at the time of operation of the master manipulator, into working amounts of said slave manipulator based on the corresponding relationship obtained in said step (6) to thereby operate said slave manipulator based on the working amounts of said slave manipulator.

2. A method in accordance with claim 1, wherein in at least one of steps (2) and (4) the plurality of target points is set with an inhomogeneous distribution.

3. A method in accordance with claim 2, wherein a plurality of target points inhomogeneously set includes a number of pairs, and wherein step (6) includes obtaining a corresponding relationship of each of said number of pairs, and said method further comprises selecting from the corresponding relationships of said number of pairs a corresponding relationship to be used when said slave manipulator is to be operated by operating said master manipulator.

4. A method for controlling master/slave manipulators in which a corresponding position shift of a master manipulator and a slave manipulator can be freely achieved, and in which a slave operation by said slave manipulator following said master manipulator is attained by comparing in a comparator an operation signal from said master manipulator and an operation signal from said slave manipulator, said method comprising the steps of:

at a time during which a corresponding position shift is to be effected, moving a leading end of said slave manipulator to a target position by operating said master manipulator;

thereafter cutting off the operation signal to said comparator from said master manipulator while inputting to said comparator the operation signal of said slave manipulator, at a time of a cutoff of the operation signal from the master manipulator, instead of the operation signal from said master manipulator; and

during a time of inputting to said comparator the operation signal from said slave manipulator instead of the operation signal from said master manipulator, shifting a leading end of said master manipulator to a desired position.

5. A method in accordance with claim 4, further comprising, during said time of inputting to said comparator the operation signal from said slave manipulator instead of the operation signal from said master manipulator, changing an enlargement ratio between the master manipulator and the slave manipulator.

6. A method for controlling master/slave manipulators in which an enlargement ratio between a master manipulator and a slave manipulator can be freely changed, and in which a slave operation by said slave manipulator following said master manipulator is attained by comparing in a comparator an operation signal from said master manipulator and an operation signal from said slave manipulator, said method comprising the steps of:

at a time during which an enlargement ratio change is to be effected, halting the operation of the master manipulator;

cutting off the operation signal to said comparator from said master manipulator while inputting to said comparator the operation signal of said slave manipulator, at a time of a cutoff of the operation signal from the master manipulator, instead of the operation signal from said master manipulator; and

during a time of inputting to said comparator the operation signal from said slave manipulator instead of the operation signal from said master manipulator, changing the enlargement ratio between the master manipulator and the slave manipulator.

7. Apparatus comprising:

a master manipulator having a leading end;

a slave manipulator having a leading end, wherein an operating area of the leading end of the master manipulator, based on a working amount β

of the master manipulator, and a working area of the leading end of the slave manipulator, based on a working amount θ

of the slave manipulator, are not similar to each other;

a control means including a memory;

wherein said memory contains corresponding relationships between working amounts of respective degrees of freedom of a first one of said master manipulator and said slave manipulator and working amounts of respective degrees of freedom of a second one of said master manipulator and said slave manipulator;

wherein the working amounts of said first one are represented by a first plurality of representing points on a first closed surface which is a limit surface of an operating area of said first one and a second plurality of representing points inside the operating area of said first one;

wherein the working amounts of said second one are represented by a first plurality of target points, which respectively correspond to said first plurality of representing points, on a second surface which is a limit surface of an operating area of said second one, and a second plurality of target points, which respectively correspond to said second plurality of representing points, inside the operating area of said second one;

wherein the working amounts of said first one are those when the leading end of said first one reaches each of the respective representing points in said first and second pluralities of representing points; and

wherein the working amounts of said second one are those when the leading end of said second one reaches the corresponding respective target point in said first and second pluralities of target points;

a master working amount detecting means for detecting said working amount β and

for inputting to said control means a signal representing the thus detected working amount β

; and

a slave operating means for receiving from said control means a signal representing the working amount θ

of said slave manipulator and for operating said slave manipulator based on the thus received signal representing said working amount θ

;

wherein, at the time of operating said master manipulator, said control means converts the working amount β

obtained from said master working amount detecting means into said working amount θ

, based on the corresponding relationships in said memory, and outputs to said slave operating means said signal representing said working amount θ

.

8. Apparatus in accordance with claim 7, wherein the corresponding relationships in said memory are corresponding relationships based on an inhomogenous distribution of target points.

9. Apparatus in accordance with claim 7, further comprising a selection command sending means;

wherein said memory contains a number of corresponding relationships for different degrees of inhomogenous distribution; and

wherein said control means selects a desired corresponding relationship from said number of corresponding relationships, based on a command from said selection command sending means.

10. Apparatus comprising:

a master manipulator for providing a master operation signal;

a slave manipulator for providing a slave operation signal;

a first comparator;

an enlargement ratio multiplier;

an adder;

a second comparator for comparing said master operation signal and said slave operation signal;

wherein said first comparator, said enlargement ratio multiplier, and said adder are interposed between said master manipulator and said second comparator in the named order beginning from the master manipulator;

a first open/close switch and a first sample-and-hold device, which are connected in series in a circuit which is in parallel to a circuit connecting said master manipulator to said first comparator, with the first open/close switch being between said master manipulator and said first sample-and-hold device; and

a second open/close switch and a second sample-and-hold device, which are connected in series in a circuit which connects said slave manipulator and said adder, with said second open/close switch being between said slave manipulator and said adder.

11. Apparatus in accordance with claim 10, further comprising:

a third open/close switch which is connected between a connection of said second sample-and-hold device to said adder and a connection of said first open/close switch to said first sample-and-hold device.