Analysis Of Energy Feeding Characteristics Of Linear Motor-driven Active Suspension

The automobile suspension system is an elastic connecting structural system connecting the body and the wheel(or axle).Traditional passive suspension is designed with fixed spring stiffness and damping parameters,which can’t be actively adjusted according to real-time road conditions,and it’s difficult to ensure the good ride comfort of vehicles in poor road conditions.In order to solve the problem that the parameters of the traditional passive suspension system cannot be self-adjusted and the energy is wasted due to road impact,this paper introduces a linear motor as the actuator of the active suspension.The new suspension system has the characteristics of non-contact,non-friction,and non-lubricating energy feeding,and the safety characteristics of the original suspension system are still retained when the motor failed.The main contents of the paper include the following aspects:(1)On the basis of the original passive suspension of the real vehicle,a new cylindrical linear motor-driven active suspension was constructed.On the basis of explaining the structure and working principle of the linear motor and the active suspension,the mathematical model of the linear motor in d-q coordinates,the energy feeding model of the linear motor with induced electromotive force and energy feeding power,and the mechanical model of the linear motor were established by coordinate transformation.Based on the simulation and verification of the above models,a quarter suspension dynamics model was established.(2)An Ansys/Maxwell finite element two-dimensional model of the linear motor was established for transient simulation,and the magnetic field of the linear motor was analyzed,which met the normal working requirements;The main size of the motor was optimized.Moreover,the rationality of the optimized motor structure was verified by analyzing the influence of parameters such as permanent magnets and air gaps on the magnetic induction intensity in the energy-feeding characteristics.(3)The random pavement model and the sinusoidal pavement model were established by MATLAB/Simulink.The four evaluation indicators of the energy-feeding characteristics were analyzed,namely,the vertical acceleration of the vehicle body,the dynamic load of the tire,the dynamic deflection of the suspension and the induced electromotive force.Simulation analysis was carried out to verify the feasibility of the suspension system energy feeding.(4)Based on the stochastic road surface model,the energy-feeding characteristics of different road grades and different vehicle speeds were simulated and analyzed;under sinusoidal road surface,the influence of road surface parameters and suspension parameters on energyfeeding characteristics is deduced.The influence of road parameters and suspension parameters on the energy-feeding characteristics was deduced,and the energy-feeding characteristics of road input amplitude,road input frequency,sprung mass,unsprung mass,suspension stiffness and wheel stiffness were simulated and analyzed;The results compared the energy-feeding effects of this suspension with several commonly used suspensions.(5)The principle prototype of the linear motor-driven active suspension was designed,and the test bench was built to conduct the energy-feeding characteristic test.The energy feeding characteristics of linear motor-driven active suspension system under sinusoidal road excitation with constant amplitude and constant frequency amplitude were studied.The experimental results were compared with the simulation results.The practical engineering application effect of the suspension energy feeding was verified by the external load.