Control energy comparison between 1st and 2nd order sliding mode approach with application to a SCARA robot

In this paper, a second order sliding mode control (SMC) design has been developed in order to realize an efficient motion control task. The objective is to realize a robust trajectory tracking behavior while achieving a significant minimization of the control energy amount, inasmuch as the energy saving has been constantly considered as a key condition, especially in the industrial sector. In a first step, a first order sliding mode controller has been developed and implemented on a robot manipulator system. Hence, aiming to improve the proposed control strategy and to reduce the energy amount consumption, a second control law approach has been developed based on the second order sliding mode design. Finally, in order to achieve required objectives in the dynamic system control, a control energy comparison between the 1st and the 2nd order sliding mode approach has been accomplished to prove the effectiveness of the higher order SMC in eliminating disturbing oscillating control signals and preserving the control energy saving. Simulation results performed on a 3 - DOF SCARA robot demonstrate improved performances with the proposed second order SMC design.