| This study presents a strategy for position feedback control, a so-called self-adjusting adaptive sliding mode controller, to obtain a desired steady state error for a DC-motor servo in the presence of Coulomb friction and stiction. Sliding mode controllers are of the type of nonlinear controllers which have been studied extensively by Russian scientists, including V. I. Utkin and V. Itkis. The self adjusting sliding mode control method that this thesis is focused on is an adaptive discontinuous controller with an approximated sliding mode trajectory. The study is concerned with both analytical and experimental performances of such a class of control strategy and a PID (proportional integral and derivative) controller in the presence of dry friction for the purpose of comparison. The study also investigates the effect of nonlinear phenomenon such as torque saturation on the states of the variables of such a system. The result of the paper is finally based on the suitable performance of the suggested control methodology utilizing a new form of sliding mode controller for the second order class of systems, rather than the conventional forms from V. Itkis and V. I. Utkin. |
