DESIGN AND ANALYSIS OF SYNCHRONIZATION FOR REAL-TIME CLOSED-LOOP CONTROL IN ROBOTICS

In the framework of the ORCCAD system, periodic and multirate control laws are implemented in terms of a set of computing tasks to be execut ed under a real-time operating system. Simulations and experiments dem onstrate that partially synchronizing such tasks can improve the pract ical performance of the implementation. However, using synchronization s may lead to dead-locks or temporal inconsistencies. In this paper, w e examine the consequences of introducing such synchronization in term s of structural and temporal problems which may occur and how they may be detected using Petri net modeling and analysis. We conclude with s ome guidelines about how to add such synchronization to design deadloc k-free and efficient implementations of real-time periodic control law s.