Study On Hydraulic Interconnected Energy-regenerative Suspension Multi-mode Switching System

The stiffness and damping of the hydraulic interconnected energy-regenerative suspension can be allocated and adjusted separately to effectively improve the vehicle riding stability and steering stability.At the same time,the suspension is widely used in heavy vehicles or off-road vehicles where a great amount of energy is wasted because of suspension violent vibration.The energy recovery unit can recover the vibration energy to achieve the purpose of energy conservation and emission reduction at the price of reducing the dynamic performance of the vehicle.On count of this,a hydraulic interconnected energy-regenerative suspension multi-mode switching system is proposed,which is designed to take into account the riding comfort and handling stability of the vehicle and effectively recover the vibration energy of the suspension at the same time.The main research content is as follows:Firstly,the dynamic model of hydraulic interconnected energy-regenerative suspension multi-mode switching system is established and a hydraulic rectifier bridge is designed to improve the stability of hydraulic system.Constant current control circuit is used in the energy-regenerative circuit to take semi-active control on the suspension system.A semivehicle and vehicle model of the hydraulic interconnected energy-regenerative suspension multi-mode switching system is built and co-simulated in AMESim and MATLAB/ Simulink.Secondly,the frequency is determined as the switching threshold of the suspension multi-mode switching system and the vehicle body acceleration,tire dynamic load and feeding power is used as the performance evaluation indicators of the system,based on which the three modes of working mode named comfort mode,safety mode and feeding mode are designed.The optimal current values of the constant current control circuit in each mode are calculated based on the simulation of the suspension multi-mode switching system.The suspension performances of the three working modes are simulated and compared on the sinusoidal road and the random road to verify the rationality of the suspension working modes designed.Thirdly,the Kalman filter is used to estimate the input speed of the road and the primary frequency of the road input is detected according to the first-order zero-crossing detection method.The reasonable working mode of the suspension system is determined according to the road input frequency detected.In order to improve the stability among the switching process,a fuzzy controller is designed to perform mode switching control and the simulation is performed.The results show that compared with the single-mode suspension system,the suspension multi-mode switching system designed can effectively reduce the vehicle body acceleration and tire dynamic load,and improve the feeding power of the suspension at the same time.Finally,the prototype of hydraulic interconnected energy-regenerative suspension multi-mode switching system is designed and the test is performed on the MTS320 fourchannel pavement simulator by selecting the sinusoidal road surface,random road surface and sectioned variable frequency sinusoidal twisted road surface as the test pavement input.The vehicle body acceleration,tire dynamic load and feeding power of the three working modes of the multi-mode switching system designed are tested to verify the effectiveness of the hydraulic interconnected energy-regenerative suspension multi-mode switching system designed.Results show that compared with single-mode suspension system,the hydraulic interconnected energy-regenerative suspension multi-mode switching system designed reduces the vehicle body acceleration and tire dynamic load by 8.94% and 18.81% respectively,and it also increases the feeding power by 18.93% at the same time under complex driving conditions.That is,the hydraulic interconnected energy-regenerative suspension multi-mode switching system designed can effectively increase the feeding power and reduce the body acceleration and tire dynamic load during driving to effectively take into account the riding comfort,handling stability and suspension feeding characteristics to meet the optimal performance of the overall conditions.