Study On Designs Of Featured Control And Bushing Spring For Double-vibration Reduction Structure Based Active Suspension

In order to provide a practical double-vibration reduction structure for a double-vibration reduction active suspension using a PMSM-ball screw actuator,a new structure of bush spring with flat outer ring and an expansion plate on the inner tube is proposed.The structural parameters of the bush spring were designed based on the ideal stiffness and damping parameters determined by the specific vibration reduction requirements.According to the nonlinear stiffness and damping of the newly designed bushing spring,a corresponding nonlinear control system is designed for double-vibration reduction active suspension.The main contents were described in these aspects detailly:Firstly,the mechanical characteristic of the prototype actuator was tested on a CNC hydraulic servo single-channel test bench.The ideal output mechanical model of the actuator prototype was modified based on the experimental analysis.The relevant parameters of the actuator modified mechanical model were identified based on the test data.The actuator model was built in MATLAB/Simulink to verify the practicality of the prototype actuator modified mechanical model.Secondly,in order to provide a practical double-vibration reduction structure for the double-vibration reduction active suspension,a new structure of bush spring with flat outer ring and an expansion plate on the inner tube is proposed.A simplified bush spring mechanical model was used to improve the H₂/H_?controller of the active suspension,and a new optimized objective function was proposed to determine the functional parameters of the bush spring structure and improved H₂/H_?controller constraint parameters.Select a rubber material on the market to make a test piece for uniaxial tensile test and shear test,and perform ABAQUS simulation according to the rubber material model parameters fitted to the test data to determine the structural parameters of the bushing spring.A nonlinear mechanical model of the bushing spring was fitted based on the ABAQUS simulation results.Thirdly,the 1/4 car model is selected as the application scenario for research,and the control system of the double-vibration reduction active suspension is designed by considering the nonlinear mechanical model of the bush spring.The actual active control force controller was designed through three steps:linearization of the control system,design and improvement of the H₂/H_?controller for the linearized control system,and inverse linearization of the control variables.The hysteresis current controlle was used to provide the real-time demand current calculated by the demanded active control force for the actuator motor.Finally,four suspension models of passive suspension,traditional active suspension structure,linear double-vibration reduction active suspension structure and non-linear double-vibration reduction active suspension structure were built in MATLAB/Simulink.The numerical analysis results show that the double-vibration reduction active suspension structure can solve the problem of active control force of the equivalent inertial mass amplification without affecting the overall performance index of the suspension.And the performance index were closed to the ideal traditional active suspension without equivalent inertial mass.