Minimizing deceleration for drop-induced shock systems using magnetorheological energy absorber

A control algorithm for shock mitigation system based on magnetorheological energy absorber (MREA) under dropinduced excitation is experimentally investigated, with the objective of “soft landing” (i.e., the final velocity of the payload exactly reduces to zero when consuming the total piston stroke of the MREA). The dynamic model of the shock mitigation system is established. A feedforward damping force tracking approach based on a basic resistor-capacitor (RC) operatorbased hysteresis model is presented and is further employed to accurately describe and predict the hysteretic nonlinearity of the MREA. According to the real-time states of the dropped mass, including the displacement, velocity and acceleration, the system controller outputs the appropriate damping force command to the MREA to achieve the desired minimized deceleration of the payload. The feasibility and the capability of the designed control algorithm are validated via simulation analyses and experimental tests.