DROP-INDUCED SHOCK MITIGATION USING ADAPTIVE MAGNETORHEOLOGICAL ENERGY ABSORBER
Energy absorbers have been developed for modern vehicles,such as aircraft,helicopters and ground vehicles,to minimize the probability of injury to occupants,or to protect avionics or electronics,during survivable crash events.Magnetorheological energy absorbers(MREAs)have the potential to revolutionize crashworthiness because they can adapt their stroking load to severity of impact and customize their maximum stroking load to the particular payload.Wereley et al.1 investigated an optimal Bingham number control strategy that achieves a soft landing(no end stop impact),while minimizing stroking load and fully utilizing available stroke.However,this method did not fully exploit the energy absorption capacity of a shock mount,and as a result,the maximum impact speed was limited.This study develops a hybrid method to adaptively control MREAs for drop-induced shock mitigation at high sink rates.The control objective is to ensure that the payload mass comes to rest at the end of the available stroke of the MREA,that is,to achieve a soft landing,without exceeding a maximum allowable stroking load that is associated with an acceptable probability of injury to the occupant or damage to equipment.To accomplish this,the equation of motion of a single-degree-of-freedom(SDOF)system with an MREA is analyzed.The control algorithm is developed as follows for a given available stroke.For impact speeds below a critical sink rate,the optimal Bingham number control algorithm is used 1.Above this critical impact speed or sink rate,the maximum MREA stroking load is initially set to the maximum allowable stroking load and held constant until the remaining damper stroke and payload velocity are such that the constant Bingham number control can be used for the terminal trajectory to ensure a soft landing.Using this hybrid control algorithm,an optimal Bingham number can be selected based on the drop velocity,payload mass,and passive damping to fully utilize the remaining MREA stroke.A second limiting critical sink rate is the sink rate at which the maximum stroking load must be used over the entire stroke.Above this sink rate,the stroking load must exceed the maximum allowable stroking load,so that unacceptable probability of occupant injury or payload damage would result.The applicable sink rate range for optimal Bingham number control(low speed),hybrid constant stroking load plus Bingham number control(high speed)are calculated,along with the maximum critical sink rate.The optimal criteria to switch between these three control methods based on the drop velocity and maximum available stroke is also presented.
magnetorheological energy absorber shock mitigation optimal Bingham number constant force control hybrid control
Mukai Wang Zhaobo Chen Norman Wereley
School of Mechatronics Engineering,Harbin Institute of Technology,Harbin,150001,China Department of Aerospace Engineering,University of Maryland,College Park,MD 20742,USA
国际会议
哈尔滨
英文
1-2
2019-09-20（万方平台首次上网日期，不代表论文的发表时间）