Research On Magnetorheological Damper And Semi-active Control Method Of Helicopter Seat

When the helicopter hits a hard landing or crashes,it will cause an impact load that will cause damage to the crew and passengers.In order to protect them,magneto-rheological energy absorber is installed in the seat system to absorb the energy transmitted to the seat when the helicopter hits the ground,thereby maximally protecting the safety of the passengers.As a smart device,magnetorheological energy absorber has the ability to adapt to different load mass and impact velocity,and is the focus of research in the field of impact.In this paper,the purpose of mitigating impact is to study the design and modeling of magnetorheological energy absorber,finite element analysis of magnetic field and flow field,optimal Bingham number control and constant damping force.The details are as follows:Based on the simpler magnetorheological energy absorber Bingham-Plastic model,a Bingham-Plastic-Minor model considering turbulence and microloss is established.An effective design strategy for magnetorheological energy absorbers under impact environment is proposed.According to the working environment requirements of the helicopter seat system,a magneto-rheological energy absorber is designed for helicopter seat system,including structural design and magnetic circuit design.The static electromagnetic field finite element analysis of the magnetorheological energy absorber is used to verify the correctness of the proposed energy absorber principle and obtain the electromagnetic characteristics of the magnetorheological energy absorber,which provides the basis for calculating the damping force.Through transient electromagnetic finite element analysis,The response time of the excitation coil is obtained.The fluid finite element analysis of the magnetorheological energy absorber is used to verify the correctness of the damping force model.Finally,the magneto-rheological damper was evaluated and it was found that the design energy absorber is superior to the same type of energy absorber.Using a optimal Bingham number control,a single-degree-of-freedom helicopter seat system model was established to analyze the presence or absence of response time,resulting in an optimal control solution in both cases.Based on the design of the magnetorheological energy absorber.The effects of different passenger masses(5^thh female,50^th male and 90^th male)and different initial impact velocitys?3m/s,4m/s and5m/s?on the optimal response of the passenger seat is analyzed.Three semi-active control strategies?BangBang control strategy,PID control strategy and fuzzy control strategy?were used to design three kinds of controllers for semi-active control simulation.The control effects and achievability of the three control strategies were compared.The fuzzy control is optimal,the PID control is second,and the Bang-Bang control is the worst.