Synthesis of sampling modes for adaptive control

Abstract

Recent studies have shown that adaptively regulating the sampling rate results in significant reduction in the computational resources of embedded software based control. Selecting a uniform sampling rate for a control loop is robust, but pessimistic for sharing processors among multiple control loops. Fine-grained regulation of periodicity achieves better resource utilization, but is hard to implement online in a robust way. However, an offline control theoretic analysis of the system illustrates the benefits of proper period selection for different modes. Such analysis reveals the necessity to automatically derive a multi-mode scheduler and converge on suitable periods for each mode. This paper proposes a methodology to automatically generate such a scheduler for an embedded real-time control system leveraging its design attributes. The proposed method provides significant gains in computational efficiency without trading off the performance.