An output feedback sliding mode speed regulator for DC drives

Synthesis of the switching surface equation in a variable structure speed controller is accomplished by using a phase lead type compensator. In addition, the switching control is designed using only the sign of the switching surface function and an estimate of the maximum value of the equivalent sliding control. As a result, the proposed variable structure controller relies only upon output feedback. The problem of control chattering is addressed by substituting a saturation function for the switching control. The practical significance of the work is demonstrated by designing a robust speed regulator for a DC drive, without direct acceleration measurement or the use of a state estimator. Results from a control experiment complement the discussion