Computation of Multibody System Dynamics by a Multiprocessor Scheme

The computation of applied torques in real time in the dynamic control of a strongly coupled multibody linkage system is complicated and time consuming. The Newton-Euler state-space formulation is used for computing the dynamics. By using this formulation, the backward recursion for calculating angular velocities and angular accelerations is eliminated. The calculation of linear acceleration is simplified, and it involves only two steps. This reduction in the height of the evaluation tree in calculating the applied torques makes parallel processing more effective. A multiprocessor system composed of a central CPU and a group of satellite CPU´s is suggested for implementing the computations. The task of each satellite CPU is to take care of one link of the system by calculating all its related data. The central CPU´s task is to compute the applied torques. Because of this arrangement, the required software system is the same for all satellite CPU´s. This modularity reduces the burden of software design greatly. The proposed multiprocessing scheme results in a flexible and modular system which is adaptive for a variety of dynamic configurations. Computer simulation results of this strategy are presented to show that the suggested multiprocessing scheme achieves a good speedup factor over the uniprocessing system.