State-based switching multi-rate controller for improving resource utilization on predictable and composable platforms

Resource sharing is a crucial design consideration in design of embedded systems for cost and resource utilization reasons. The system-level performance is negatively influenced by resource sharing due to inter-application interference. For a control application, this further implies a trade-off between the resource utilization and the control performance. For a control application, the sampling rate is an important knob to perform trade-off between resource utilization and the control performance. In this paper, we present a state-base switching multi-rate controller (SSMC) scheme targeting predictable and composable multi-core platforms. In the proposed scheme, the controller switches between multiple sampling rates (or application periods) based on the state of the system i.e., the transient and steady state. We propose two multi-rate control laws targeting SSMC — one using single gain and one using multiple gains over different actuating points. We address the impact of model uncertainty by using a parallel observer system. We validate the effectiveness of the proposed scheme performing hardware-in-the-loop simulations targeting an industrial multi-core platform — Verintec, synthesized on a PYNQ Z2 FPGA board. Finally, we demonstrated that the proposed scheme outperforms the state-of-the-art techniques in terms of resource utilization and the control performance.