Reduced-order Output Feedback Controllers Research Articles

Reduced-order output feedback controllers for the robust H∞ performance problem

This note considers robust H∞ control problems for a class of systems with time-varying uncertainty lying in a hyperrectangle. It has two features: (i) Output feedback controllers are discussed instead of the state feed-back ones. It is proved that the problem can be reduced to finite-dimensional convex programming problems of finite vertex LMIs. All desired output feedback controllers can be parameterized based on the solutions of 2m LMIs. (ii) Reduced-order controller design is considered and the design idea is also formulated as solutions to LMIs. These results are also an extension of the main theorems about reduced-order controllers discussed in ref. [8] for uncertain systems. Based on the approaches presented here, similar problems in the discrete-time case could be dealt with.

Disturbance Attenuation Via a Reduced-Order Output Feedback Controller for Rigid Robotics Manipulators

This note presents a solution to the problem of external disturbance attenuation in robotics systems via a reduced-order output feedback controller. The proposed controller based on a point-to-point control law ensures both asymptotic stability of the equilibrium point of the robot system and external disturbance attenuation. The approach is based on the notion of the L2-gain.

Output feedback control of nonminimum-phase nonlinear processes

This work concerns the development of a general framework for the analysis and output feedback control of open-loop stable nonminimum-phase nonlinear processes. A Smith-type abstract operator structure is introduced, allowing the reduction of the controller synthesis problem for nonminimum-phase processes to the one for minimum-phase processes. State-space methods are used to derive a reduced-order output feedback controller that induces a desired input/output behavior for processes with unstable inverse dynamics and deadtime. The underlying structure of the reduced-order controller is also identified and studied. Finally, an example from a class of chemical reaction systems with nonminimum-phase characteristics is used for evaluating the performance and robustness of the developed control method.