| The traditional passive suspension system can neither adjust the required damping force in real time according to different driving conditions and complex road conditions of the vehicle,nor balance the operational stability and comfort when the vehicle is running.The semi-active suspension system can match the damping force requirements required for the suspension in real time and adjust it according to the actual situation.The magnetorheological damper as a semi-active suspension system actuator has the advantages of simple structure,controllable damping force,large output damping force,fast response speed,large power adjustment coefficient,relatively simple control,and low energy consumption.It has become the main research direction of semi-active suspension.In this paper,the maximum damping force and the maximum dynamic adjustable coefficient of the magnetorheological damper were taken as the objective function,the parameters of the piston assembly structure were taken as the optimization variables,and the influencing factors of the maximum damping force and the maximum dynamic adjustable coefficient were obtained.The multi-objective genetic algorithm was used to optimize the design of the magnetorheological damper by using the mode FRONTIER multi-objective optimization software.The magnetic circuit simulation results were verified by using magnetic field simulation software Ansoft Maxwell.It was concluded that the average magnetic induction intensity of the optimized structure was greatly improved.Finally,the prototype of the magnetorheological damper was made with the optimized solution and the performance characteristics test was carried out to analyze the performance of the magnetorheological damper.The reliability of the design method of the damper was verified by experiments.The specific works carried out are as follows:(1)In this paper,according to the requirements of the suspension damper of a certain type of vehicle,the design principle of the single-cylinder single-outlet magnetorheological damper was proposed.According to the selected working mode and structure type,the mechanical properties of magnetorheological damper were analyzed,and the formula for calculating the damping force was obtained.The structural design process of the magnetorheological damper was introduced in detail.The basic principles of the structural design of the magnetorheological damper were proposed.The overall and the structural parameters of each assembly were designed and checked.The magnetic circuit design was based on the magnetic circuit design theory.Finally,the main structural parameters and material selection of each component that met the requirements were initially determined.(2)According to the preliminary design of the structural parameters of the magnetorheological damper,the simulation structure model was established and the electromagnetic field simulation was performed.Firstly,the magnetic circuit saturation of the magnetorheological damper was analyzed.Then,through the simulation of the magnetic circuit of the single and double-stage coils,it was found that the magnetic field distribution of the reverse current of the two-stage coil was uniform and difficult to reach saturation.Finally,the influence of different structural sizes of the piston assembly on the average magnetic induction intensity at the working gap of the damping channel was explored.The results showed that the working clearance of the damping channel was designed to be between 0.8 and 1.5 mm,the radius of the piston rod was between 5.5 and 7.5 mm,the thickness of the piston casing was between 2.5 and 4.0 mm,and the effective length of the damping channel was between 25 to 28 mm.According to the number of turns required in this paper,the depth design of the coil groove was reasonable between 5 and 7mm.(3)In order to improve the efficiency of structural design of magnetorheological damper,this paper adopted the improved non-dominated genetic algorithm to design multi-objective optimization of structural parameters of magnetorheological damper.The optimization results showed that the most important factors affecting the maximum damping force were the coil groove depth and the effective half-length of the damping channel,and the most important factors affecting the maximum dynamic adjustable coefficient were the clearance of the damping passage and the length of the noneffective area of the damping channel.The magnetic circuit electromagnetic simulation of the optimized structure of the magnetorheological damper was carried out to verify whether the magnetic induction intensity of each area of the optimized piston assembly structure meets the requirements.The simulation results showed that the magnetic induction intensity at the effective length of the damping passage after optimization of piston assembly structure was obviously greater than that before optimization.The average magnetic induction intensity at the effective length of the damping passage before optimization was 460 m T.The average magnetic induction intensity at the effective length of the damping passage after optimization was 576 m T,which increasesed by nearly 25.2%,and greatly improved the magnetic induction intensity at the damping passage and had not reach the magnetic saturation strength value of each material,which met the design goal;The magnetic induction intensity at the length of the non-effective area of the damper channel was almost 0 m T,which made full use of the magnetic induction intensity at the damper channel,thereby increasing the range of the adjustable damping force and meeting the design requirements.(4)Using the before and after optimized structural parameters to make the prototype of the magnetorheological damper,according to QC/T545-1999 ?Automobile barrel damper bench test method?,the PWS-16 electro-hydraulic servo damper comprehensive performance test rig was used to test the damper's dynamometer and speed characteristics.By changing the speed of the damper and the magnitude of the load current,the output damping force of the self-made damper under different conditions was obtained.The experimental results showed that the performance curve of the self-made magnetorheological damper obtained under each condition was smoother and fuller.By analyzing the output damping force,it can be seen that the ratio between the damping force and the viscous damping force of Kulun reached the dynamic adjustment coefficient of the design requirements,so the structure of the design was full of practical application requirements.The output damping force of the magnetorheological damper with optimized structure is larger than that before the optimization.In the case of 0A and the maximum velocity,the resilience increased by 15.7% and the compression force increased by 36.8%.At 3A and the maximum velocity,the resilience increased by 3.5%,and the compression force increased by 21.5%.The reliability of the magnetic circuit design and multi-objective optimization method in this paper has been verified,which has certain reference value for the design of magnetorheological damper in the future. |
PDF Full Text Request