Robust time delay compensation in a wireless motion control system with double disturbance observers

Time delay is a common phenomenon which can be varying and unknown in many networked motion control systems. Since time delay negatively affects the stability and tracking performance, it needs to be carefully handled in controller design. Moreover, both external disturbance and sensor noise exist in such systems, which makes the controller design more challenging. In this paper, a double disturbance observer (DDOB) structure is proposed to handle time delay, external disturbance, and measurement noise simultaneously. Design of disturbance observers (DOBs) and baseline controllers are elaborated. An RT-WiFi wireless network is developed for high-speed and real-time control applications. The RT-WiFi network is integrated with a DC motor and its performance is examined. Simulation and experimental results are demonstrated to verify the effectiveness of the proposed algorithm.