Design and application of second order sliding mode control algorithms
The thesis considers the development and application of second order sliding mode control algorithms. Second order sliding mode control keeps the main advantages of standard sliding modes and has the additional advantage that it can be used to remove chattering effect, providing smooth or at least piecewise smooth control. The method also provides better accuracy with respect to switching delays.;A comparison has been made between dynamic sliding modes and higher order sliding modes. The application of dynamic sliding mode control has been demonstrated for systems not affine in the control in a MIMO case study for the control of an IC engine. The super-twisting algorithm has been implemented for robust speed control of a diesel engine available in the laboratory where the sliding variable has relative degree one with respect to the control input. A theoretical case has been made for the application of the algorithm and bounds on the controller parameters have been generated. The implementation results demonstrate the practical importance of higher order sliding mode control.;A new second order-sliding algorithm has been developed to stabilize systems where the sliding variable has relative degree two with respect to the control input. More over, it does not require the derivative of the sliding variable to be measured or observed and hence reduces the number of sensors required for control implementation. Closed loop simulation of various systems has been carried out to validate the theory. The algorithm has been applied using dSPACE for position and speed control of a DC motor in SISO configuration.;The algorithm has also been extended for a class of nonlinear uncertain MIMO systems. A MIMO case study for water level control in coupled twin-tanks system has been presented. The controller has been implemented in the laboratory to validate the theoretical assertions made in the thesis.