Enabling Wireless Network Support for Gain Scheduled Control

Abstract

To enable cooperation of cyber-physical systems in latency-critical scenarios, control algorithms are placed in edge systems communicating with sensors and actuators via wireless channels. The shift from wired towards wireless communication is accompanied by an inherent lack of predictability due to interference and mobility. The state of the art in distributed controller design is proactive in nature, modeling and predicting (and potentially oversimplifying) channel properties stochastically or pessimistically, i. e., worst-case considerations. In contrast, we present a system based on a real-time transport protocol that is aware of application-level constraints and applies run-time measurements for channel properties. Our run-time system utilizes this information to select appropriate controller instances, i. e., gain scheduling, that can handle the current conditions. We evaluate our system empirically in a wireless testbed employing a shielded environment to ensure reproducible channel conditions. A series of measurements demonstrates predictability of latency and potential limits for wireless networked control.