Computation of customized symbolic robot models on peripheral array processors

The authors address the problem of the optimal evaluation of robot inverse dynamics on array processors. The inverse dynamics models used are the symbolic customized models with near-minimum numerical complexity, which are computer-generated given the robot arm parameters. Such models represent the input for a proposed scheduling algorithm that distributes the computation of the model over several multipliers and adders. The scheduling algorithm is automatic and minimizes the number of microcycles. The algorithm was tested on several standard robots, and processor efficiency up to 84% was achieved. Experimental results on a 30 MFLOPS array processor showed that the inverse dynamics of a three-link PUMA-like robot requires 25.5 μs. For a six-link robot, the computation of the inverse dynamics and the control law takes about 100 μs on this processor. Thus, the control of high-speed robots could be achieved by attaching low-cost array processors (10 MFLOPS) to the control processor of the robot controller