Asymptotic Output Tracking With Malfunctioning Actuators and Twisted/Biased Feedback

It is highly desirable yet challenging to maintain stable system operation in the presence of unexpected malfunctioning sensors and actuators arising from internal component faults and/or external malicious attacks. In this note, we investigate the reliable control problem for a class of nonlinear systems with mismatched modeling uncertainties and unknown control gain matrix as well as abnormal actuating and sensoring units. Such malfunctioning sensors and actuators not only bring about additional modeling uncertainties but also literally pollute the original control influence gain matrix, making the underlying problem further complicated. By using the backstepping-like design procedure, we present an adaptive control solution with relaxed controllability conditions, capable of achieving asymptotic stabilization under severely twisted feedback information due to malicious attacks/sensor failures. Besides a primary actuator, we also propose a strategy to use additional actuators as the backup ones to enhance system survivability, where the actuator replacement automatically and seamlessly takes place from the primary actuator to a backup one, once a severe failure at the primary actuator is detected. Numerical simulation also confirms the effectiveness and benefits of the proposed method.