Modified Preview Control for a Wireless Tracking Control System With Packet Loss

In this paper, a modified preview control technique is proposed to compensate packet loss in a wireless tracking control system, where future reference signals over a finite horizon can be previewed. In order to utilize the future reference information for controller design, the system model is augmented with a reference generator whose states are the future reference signals. As a response to the packet loss that occurs in the wireless network, the preview control technique is modified by employing Bernoulli variables to represent packet losses in both controller-actuator and sensor-controller channels. The Bernoulli packet loss model, along with tracking errors and control inputs, is included in a quadratic cost function, and the optimal controller gain that minimizes the cost function is obtained by dynamic programming. A modified Kalman filter considering packet loss is utilized for full state estimation and state feedback control. Stability of the modified preview control system is studied using linear matrix inequalities (LMIs). Choice of preview horizon is discussed and performance of the proposed controller is verified by simulation and experimental results.