Comments

Supported in part by the National Science Foundation Engineering Research Center Grant CDR 8500022. Any opinions, findings, and conclusions or recommendations expressed in this article are those of the authors and do not necessarily reflect the views of the funding agency.

Abstract

Computing the robot forward dynamics is important for real-time computer simulation of robot arm motion. Two efficient parallel algorithms for computing the forward dynamics for real-time simulation were developed to be implemented on an SIMD computer with n. processors, where h is the number of degrees-of-freedom of the manipulator. The first parallel algorithm, based on the Composite Rigid-Body method, generates the inertia matrix using the parallel Newton-Euler algorithm, the parallel linear recurrence algorithm, and the row-sweep algorithm, and then inverts the inertia matrix to obtain the joint acceleration vector desired at time t. The time complexity of this parallel algorithm is of the order 0(n2) with 0(n) processors. Further reduction of the order of time complexity can be achieved by implementing the Cholesky’s factorization procedure on array processors. The second parallel algorithm, based on the conjugate gradient method, computes the joint accelerations with a time complexity of 0(n) for multiplication operation and 0(nlogn) for addition operation. The proposed parallel computation results are compared with the existing methods.

Date of this Version

2-1-1987

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