Research On Performance And Bench Test Of Magnetorheological Semi-active Suspension System

The magnetorheological damper has the function of changing the damping coefficient under the energized magnetic field,and has a large dynamic adjustable range,a fast response speed and low power requirements.Therefore,the semi-active suspension with the magnetorheological damper is gradually becoming a research hotspot.The fast and accurate control of the damping characteristics of magnetorheological dampers requires high-precision dynamic models to characterize their dynamic characteristics,and then the design and development of the controller could be performed.At present,most of the existing models cannot accurately describe the strong nonlinear characteristics of magnetorheological dampers under different excitation conditions,and the research on magnetorheological semi-active suspension systems lacked experimental verification.In the early stage of research and development,the magnetorheological semi-active suspension system mainly relied on simulation and bench test methods.In this paper,a bench test platform for magnetorheological semi-active suspension system was built and a complete semi-active control program including magnetorheological damper magic formula model and the control strategy of acceleration drive damping was established.The magnetorheological semi-active suspension system was studied by simulation and bench test methods.In this paper,based on the 2 degree of freedom dynamics model of 1/4 vehicle suspension system,the different damping coefficients were selected to analyze the frequency domain characteristics of the suspension system.The results showed that in different excitation frequency bands,different damping coefficients were required to achieve the desired performance of the suspension system,which lays a theoretical foundation for the study of the damping adjustable semi-active suspension.According to the bench test method of automobile cylinder damper QC/T545-1999,the vibration excitation experiment of a magneto-rheological damper was carried out under different excitation frequency,stroke and control current.According to the experimental data,the magic formula of the magnetorheological damper was established by using the least squares parameter identification method.The inverse kinetic model was obtained by a direct inverse push method.These work provided damper models for magnetorheological semi-active suspension simulation and bench control experiments.The 1/4 vehicle magnetorheological semi-active suspension system bench test platform was designed and built.Among them,the electro-hydraulic servo excitation system could realize four kinds of excitation signals of random road surface,impact,sine and sweep.The LMS Test.Lab test system quantified the vibration state of a quarter-vehicle suspension system by collecting acceleration and body height sensor signals.As the carrier of the control strategy,the rapid prototype controller provided a reliable software and hardware system for the realization of magnetorheological semi-active suspension control.The reliability of the input and output during the control process was guaranteed by debugging the motion state signals of acceleration,velocity and displacement obtained by the sensor and establishing the relationship between the PWM output and the control current I.Based on the established forward and reverse dynamics model of the magnetorheological damper magic formula,a two-degree-of-freedom 1/4 vehicle magnetorheological semi-active suspension system simulation model was built in Matlab/Simulink.The impact and random road surface excitation simulation experiments were carried out using an acceleration-driven damping control strategy.The effectiveness of the complete control strategy of the magnetorheological damper magic formula model and the control algorithm was verified,which laid a good foundation for the bench control test.A complete control program containing the damper magic formula model and control algorithm was built in Simulink and compiled into the rapid prototype controller.Then,the semi-active control test of impact and random road excitation was carried out on the test platform of the magnetorheological semi-active suspension bench.The test showed that the magnetorheological semi-active suspension bench test platform could effectively implement the magnetorheological semi-active suspension control test.The forward and reverse dynamics models of the magnetorheological damper magic formula were successfully applied to semi-active control;The acceleration-driven damping control strategy effectively improved the comfort performance of the suspension system.