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On-line method and apparatus for coordinated mobility and manipulation of mobile robots

  • US 5,550,953 A
  • Filed: 04/20/1994
  • Issued: 08/27/1996
  • Est. Priority Date: 04/20/1994
  • Status: Expired due to Fees
First Claim
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1. 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).

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