SUPER-TWISTING OBSERVER-BASED INTEGRAL SLIDING MODE CONTROL FOR TRACKING THE RAPID ACCELERATION OF A PISTON IN A HYBRID ELECTRO-HYDRAULIC AND PNEUMATIC SYSTEM

A new hybrid electro-hydraulic and pneumatic actuator system and its dynamic model for high-performance control are presented. This work focuses on tracking control of rapidly changing acceleration that is an advanced area with various practical applications in industries. The impact motion control of the actuator is one of challenging task due to the system instability during the transition state. Since composite disturbances derived from the inaccurate and unmodeled dynamics considerably reduce the control performance. A novel structure of variable integral sliding mode controls integrated with a sliding mode disturbance observer is proposed based on the super-twisting algorithm. With the control strategy, not only does the controller overcome the extreme sensitivity of the system during rapid movements, but it also eliminates the internal parameter uncertainties and external load disturbance while tracking rapid gain-scheduled acceleration. The results of the numerical simulation and field experiment are presented to assess the effectiveness of the proposed control scheme.