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US5550953A
Expired / Lapsed
US
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On-line method and apparatus for coordinated mobility and manipulation of mobile robots
Assignee: California Institute of Technology
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Filing: 1994-04-20
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Granted: 1996-08-27
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Expires: 2014-04-20
Abstract
Abstract A simple and computationally efficient approach is disclosed for on-line coordinated control of mobile robots consisting of a manipulator arm mounted on a mobile base. The effect of base mobility on the end-effector manipulability index is discussed. The base mobility and arm manipulation degrees-of-freedom are treated equally as the joints of a kinematically redundant composite robot. The redundancy introduced by the mobile base is exploited to satisfy a set of user-defined additional tasks during the end-effector motion. A simple on-line control scheme is proposed which allows the user to assign weighting factors to individual degrees-of-mobility and degrees-of-manipulation, as well as to each task specification. The computational efficiency of the control algorithm makes it particularly suitable for real-time implementations. Four case studies are discussed in detail to demonstrate the application of the coordinated control scheme to various mobile robots.
Inventors
- 👤 Homayoun Seraji
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 18:34
CPC Classifications
B; B25; B25J; B25J9/00; B25J9/16; B25J9/1615; B25J9/162; G; G05; G05B; G05B2219/00; G05B2219/30; G05B2219/39; G05B2219/39081; G05B2219/39172; G05B2219/39174; G05B2219/40; G05B2219/40252; G05B2219/40293; G05B2219/40297; G05B2219/40298; G05B2219/40327; G05B2219/40349
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
230 words
A method of controlling a mobile robot, the robot of the type having a mobile base having at least one degree of mobility and a manipulatable arm having at least one degree of manipulation; the method comprising the steps of: (a) generating a forward kinematic model that relates arm and base joint coordinates to end-effector coordinates; (b) generating a differential kinematic model that relates end-effector velocity to arm and base joint velocities including Jacobian matrices of the arm and base, respectively; (c) augmenting by column the arm Jacobian matrix with the base Jacobian matrix to obtain an overall end-effector Jacobian matrix where the availability of base mobility appears as extra columns in the end-effector Jacobian matrix because of effectively increasing the dimension of the joint space; (d) augmenting by row the end-effector Jacobian matrix of step (c) with a constraint Jacobian matrix which relates to a user-defined additional task to be accomplished due to kinematic redundancy where said additional task results in extra rows in the end-effector Jacobian matrix due to an increase of the task space; (e) selecting end-effector and constraint task weighting factors and arm and base joint velocity weighting factors; (f) finding the optimal arm and base motions using a closed-loop damped-least-squares approach; and (g) moving the arm and base of said robot in accordance with the optimal motions resulting from carrying out steps (a) through (f).
Claim 2
Independent Claim
230 words
A method of controlling a mobile robot, the robot of the type having a mobile base having at least one degree of mobility and a manipulatable arm having at least one degree of manipulation; the method comprising the steps of: (a) generating a forward kinematic model that relates arm and base joint coordinates to end-effector coordinates; (b) generating a differential kinematic model that relates end-effector velocity to arm and base joint velocities including Jacobian matrices of the arm and base, respectively; (c) augmenting by column the arm Jacobian matrix with the base Jacobian matrix to obtain an overall end-effector Jacobian matrix where the availability of base mobility appears as extra columns in the end-effector Jacobian matrix because of effectively increasing the dimension of the joint space; (d) augmenting by row the end-effector Jacobian matrix of step (c) with a constraint Jacobian matrix which relates to a user-defined additional task to be accomplished due to kinematic redundancy where said additional task results in extra rows in the end-effector Jacobian matrix due to an increase of the task space; (e) selecting end-effector and constraint task weighting factors and arm and base joint velocity weighting factors; (f) finding the optimal arm and base motions using a closed-loop damped-least-squares approach; and (g) moving the arm and base of said robot in accordance with the optimal motions resulting from carrying out steps (a) through (f).
Claim 3
Dependent Claim
39 words
The method recited in claim 1 wherein said kinematic redundancy recited in step (d) results from a task space which is at least one dimension less than the sum of the revolute joints and prismatic joints of said robot.
Claim 4
Dependent Claim
14 words
The method recited in claim 1 wherein said mobile robot is a tracked robot.
Claim 5
Dependent Claim
14 words
The method recited in claim 1 wherein said mobile robot is a gantry robot.
Claim 6
Dependent Claim
14 words
The method recited in claim 1 wherein said mobile robot is a wheeled robot.
Claim 7
Dependent Claim
14 words
The method recited in claim 1 wherein said mobile robot is a compound robot.
Claim 8
Dependent Claim
36 words
The method recited in claim 1 wherein the number of degrees-of-freedom of said mobile robot is equal to the sum of the number of degrees-of-manipulation of said arm and the number of degrees-of-mobility of said base.
Claim 9
Dependent Claim
31 words
The method recited in claim 1 wherein said end-effector and constraint task weighting factors are selected on-line based on user requirements for real-time implementation of on-line control of said mobile robot.
Claim 10
Independent Claim
256 words
A method for on-line, real-time control of a mobile robot having a mobile base and a manipulatable arm mounted on the base to provide a number of degrees-of-freedom equal to the sum of the number of degrees-of-base-mobility and the number of degrees-of-arm-manipulation, the robot operating in a multi-dimension task space wherein the number of task-space-dimensions is less than the degrees-of-freedom; the method comprising the steps of: (a) generating a forward kinematic model that relates arm and base joint coordinates to end-effector coordinates; (b) generating a differential kinematic model that relates end-effector velocity to arm and base joint velocities including Jacobian matrices of the arm and base, respectively; (c) augmenting by column the arm Jacobian matrix with the base Jacobian matrix to obtain an overall end-effector Jacobian matrix where the availability of base mobility appears as extra columns in the end-effector Jacobian matrix because of effectively increasing the dimension of the joint space; (d) augmenting by row the end-effector Jacobian matrix of step (c) with a constraint Jacobian matrix which relates to a user-defined additional task to be accomplished due to kinematic redundancy where said additional task results in extra rows in the end-effector Jacobian matrix due to an increase of the task space; (e) selecting end-effector and constraint task weighting factors and arm and base joint velocity weighting factors; (f) finding the optimal arm and base motions using a closed-loop damped-least-squares approach; and (g) moving the arm and base of said robot in accordance with the optimal motions resulting from carrying out steps (a) through (f).
Claim 11
Independent Claim
256 words
A method for on-line, real-time control of a mobile robot having a mobile base and a manipulatable arm mounted on the base to provide a number of degrees-of-freedom equal to the sum of the number of degrees-of-base-mobility and the number of degrees-of-arm-manipulation, the robot operating in a multi-dimension task space wherein the number of task-space-dimensions is less than the degrees-of-freedom; the method comprising the steps of: (a) generating a forward kinematic model that relates arm and base joint coordinates to end-effector coordinates; (b) generating a differential kinematic model that relates end-effector velocity to arm and base joint velocities including Jacobian matrices of the arm and base, respectively; (c) augmenting by column the arm Jacobian matrix with the base Jacobian matrix to obtain an overall end-effector Jacobian matrix where the availability of base mobility appears as extra columns in the end-effector Jacobian matrix because of effectively increasing the dimension of the joint space; (d) augmenting by row the end-effector Jacobian matrix of step (c) with a constraint Jacobian matrix which relates to a user-defined additional task to be accomplished due to kinematic redundancy where said additional task results in extra rows in the end-effector Jacobian matrix due to an increase of the task space; (e) selecting end-effector and constraint task weighting factors and arm and base joint velocity weighting factors; (f) finding the optimal arm and base motions using a closed-loop damped-least-squares approach; and (g) moving the arm and base of said robot in accordance with the optimal motions resulting from carrying out steps (a) through (f).
Claim 12
Dependent Claim
39 words
The method recited in claim 9 wherein said kinematic redundancy recited in step (d) results from a task space which is at least one dimension less than the sum of the revolute joints and prismatic joints of said robot.
Claim 13
Dependent Claim
14 words
The method recited in claim 9 wherein said mobile robot is a tracked robot.
Claim 14
Dependent Claim
14 words
The method recited in claim 9 wherein said mobile robot is a gantry robot.
Claim 15
Dependent Claim
14 words
The method recited in claim 9 wherein said mobile robot is a wheeled robot.
Claim 16
Dependent Claim
14 words
The method recited in claim 9 wherein said mobile robot is a compound robot.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-08-27 | 2000-02-26 | 2000-08-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-08-27 | 2004-02-26 | 2004-08-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-08-27 | 2008-02-26 | 2008-08-27 | $7700.00 | Window Closed / Lapsed |