Research On Helicopter Seat Buffer Control Based On Magnetorheological Technology

The seat serves as the last line of defense to ensure the safety of human body when the helicopter crashes,and has a very crucial role.Traditional helicopter seats use passive energy-absorbing devices to dissipate impact energy,which can only achieve good energy-absorbing effects under specific working conditions.As a new semi-active intelligent device,the magnetorheological buffer can adjust the input current to change the damping force or torque according to the control strategy under different working conditions,and the energy consumption required is lower than that of active control,at present,some scholars have applied it to the cushion of helicopter seats,but the actuator is mainly the linear magnetorheological buffer,which is greatly affected by the speed and has low controllability,however,the rotary magnetorheological buffer is less affected by speed,which is more conducive to the design and implementation of control strategies.Therefore,in this paper,the helicopter seat buffer system based on rotary magnetorheological buffer is studied,the design method and control strategy of the magnetorheological buffer are explored,the main work has the following aspects:(1)The helicopter seat magnetorheological buffer system is established,and a rotary magnetorheological buffer is designed.According to the helicopter seat buffering requirements,the structural design and the finite element simulation analysis of buffer are carried out,the calculation model of the damping torque of the magnetorheological buffer is derived.(2)Based on the designed parameters of magnetorheological buffer,a prototype of the rotary magnetorheological buffer is developed,low-speed torsion and high-speed continuous rotation tests are carried out.According to the low-speed torsion test results,the basic mechanical properties of the magnetorheological buffer are analyzed.Based on the high-speed continuous rotation test results,the mechanical properties of the buffer at high speed are analyzed,and a mechanical model of the buffer is established.(3)The human-seat multi-degree-of-freedom dynamic model of the helicopter seat magnetorheological buffer system is established,the control strategy is designed,and the simulation analysis is carried out.With the goal of making full use of the stroke,a control strategy that adjusts the force according to the working conditions to optimize the buffering effect is designed;and the evaluation criteria for the helicopter seat system are established.The simulation under multiple working conditions is carried out and compared with the simulation under passive energy absorber.The simulation results verify the effectiveness of control strategy.(4)A helicopter seat drop test system is designed and built,and the verification tests of the helicopter seat magnetorheological buffer system’s feasibility and the control strategy’s effectiveness are conducted.The test results show that under different currents,the helicopter seat magnetorheological buffer system can effectively change the buffer stroke,and the force is stable with the stoke.Under the effect of the control strategy,the buffer stroke can be fully utilized,the acceleration of seat meets the standard,which can protect human better.