Speed Sensorless and Sensor-Fault Tolerant Optimal PI Regulator for Networked DC Motor System With Unknown Time-Delay and Packet Dropout

Sensorless and sensor-fault-resilient control of a networked dc motor system (NDCMS) with an optimal integral-square-error proportional-integral (PI) controller is considered, while network-induced delays and packet dropouts are taken into account. A sliding-mode observer is developed to estimate rotor speed and unknown load torque for the networked system. Then, a PI controller is designed such that the overall NDCMS with complete or partial sensor failure is stabilized and a linear quadratic cost function is sufficiently minimized. Optimal controller parameters are determined by solving bilinear matrix inequalities. The numerical and experimental tests are performed to evaluate the feasibility and applicability of the networked sensorless or sensor-fault-tolerant controller. The results show good performance in both estimation and control objectives.