Output feedback control for linear systems with sensor limitations

In this paper, the control problems for linear systems with sensor constraints are investigated in a united framework, and the extended state observer (ESO) based control approaches are proposed to actively reject the sensor constraints, such as sensor noises, sensor nonlinearities and sensor faults. The ESO-based control approaches include two parts: one is to construct the ESO for systems with sensor constraints, and the other is to design the ESO-based controllers to actively reject the effects of the sensor constraints in the output channels. The existence conditions in terms of matrix rank criterion of the ESO is also established. Then, the disturbance rejection gains are designed analytically, and both the stability and disturbance rejection analysis are performed. It is shown that, with the proposed ESO-based controllers, the sensor constraints can be rejected from the output channel at the steady state successfully. Finally, numerical examples are provided to illustrate the efficiency and advantages of the proposed methods.