TitleSliding mode control for systems with slow and fast modes
NameNguyen, Thang Tien (author), Gajic, Zoran (chair), Pompili, Dario (internal member), Spasojevic, Predrag (internal member), Su, Wu-Chung (outside member), Rutgers University, Graduate School - New Brunswick,
SubjectElectrical and Computer Engineering,
Sliding mode control
DescriptionThis dissertation addresses the problems of sliding mode control for systems with slow and fast dynamics. A system using a sliding mode control strategy can display robust performances against parametric and exogenous disturbances under the matching condition (Drazenovic's condition). We investigate the problem of output feedback sliding mode control for sampled-data systems with an unknown external disturbance. Given an output sliding surface, we construct a discrete-time control law. Since the external disturbance in the control law is unknown, we approximate it by system information from the previous time instant. The synthesized control law provides promising results with high robustness against the external disturbance. These results are further improved by a method which better approximate the disturbance by system information from two previous time instants. The stability and robustness of the closed-loop system are analyzed by studying a transformed singularly perturbed discrete-time system. The second topic is to study sliding mode control for singularly perturbed systems which exhibit slow and fast dynamics. A state feedback control law is designed for either slow or fast modes. Then, the system under that state feedback control law is put into a triangular form. In the new coordinates, a sliding surface is constructed for the remaining modes using Utkin and Young's method. A sliding mode control law is synthesized by a method which is an improved version of the unit control method by Utkin. Lastly, a composite control law is synthesized from the two components. The topic is also addressed by Lyapunov approaches. A state feedback composite control law is designed to stabilize the system. Accordingly, Lyapunov functions are constructed to synthesize a sliding surface. Two sliding surfaces and two sliding mode controllers are proposed. Asymptotic stability and disturbance rejection are achieved. Sliding mode control for singularly perturbed discrete-time systems with parametric uncertainties is also investigated. Proceeding along the same lines as in the continuous-time case, we propose two approaches to construct a composite control law. It is shown that the closed-loop system under the proposed control laws is asymptotically stable provided the perturbation parameter is small enough.
NoteIncludes bibliographical references
Noteby Thang Tien Nguyen
CollectionGraduate School - New Brunswick Electronic Theses and Dissertations
Organization NameRutgers, The State University of New Jersey
RightsThe author owns the copyright to this work.