Fault-tolerant sliding mode control design for an electromechanical system

The purpose of this thesis is to propose an adaptive dynamic proportional–integral–derivative sliding surface based second-order fault-tolerant sliding mode controller for speed control of an electromechanical system under uncertainties and disturbances. The sliding-mode control technique is a robust control scheme that obtains the desired output with a concept of changing the controller's structure in response to change the state of the system. The online adaption skill of adaptive control makes it superior to sliding mode control in terms of constant or slowly-varying parameters for a non-linear dynamical system having uncertainties. Fault-tolerant control schemes are utilized commonly in safety-critical systems. This study aims to show how to utilize the robust properties of second-order adaptive dynamic sliding-mode control on the problem of component fault. The control design process prioritizes, even in the existence of the unsuitable conditions, providing the closed-loop stability for overall system. The Lyapunov theorem is used for affirming the design and stability of the closed-loop system. The presented adaptive dynamic first and second-order fault-tolerant sliding-mode controllers and the traditional sliding-mode controller are compared with each other and the results are discussed. The experimental results of the proposed fault-tolerant controller, concerning parametric uncertainties and disturbances, acquire suitable tracking performance and show more robustness than the traditional sliding-mode control.