Study On Magnetorheological Semi-active Seat Suspension Three-stage Control

The suspension of commercial vehicles and construction machinery are often stiff,and the driving environments are relatively harsh.Passengers will continue to experience various types of vibration or shock while driving,which may cause physical discomfort.Long-term exposure to such an environment will lead to various physical diseases,and the serious vibration will affect the driver’s operations.Therefore,as the key step of vehicle vibration isolation,the seat plays an important role in protecting the occupants and improving comfort and safety.Seat suspension can generally be divided into passive suspension,active suspension and semi-active suspension.Among them,the passive suspension is difficult to adjust for different working conditions due to the fixed parameters,while the active suspension has excellent vibration isolation effect,but the structure is complex and the cost is high.The semi-active seats have received extensive attention due to their relatively simple structure and their ability to reduce vibrations according to environmental changes,and the magnetorheological semi-active suspension has attracted the attention of many researchers because of the advantages of fast speed,low energy consumption,and large response range.How to design an algorithm to control the seat suspension to accurately judge the working state and respond to it is a crucial link in the design of the semi-active seat suspension,which has important research significance.There have been many studies on semi-active seat control algorithms,but they mainly focus on improving seat vibration isolating performance,increasing comfort,and reducing vibration amplitude.There is a lack of targeted research on the extreme conditions that lead to End-stop impact,which may cause serious discomfort.At the same time,in order to improve the adaptability and accuracy of seat control algorithms,the difficulty of new algorithms is also increasing,which often leads to an increase in seat hardware requirements,making it difficult for the algorithms to be practically applied.Based on the above problems,this paper not only improves the comfort and safety of the seat and reduces the vibration amplitude,but also designs the control to prevent the seat from impacting the limit.The dynamic model of the chair suspension is studied and analyzed from the aspects of simulation and experiment.The main contents of this paper are divided into the following aspects:(1)The excitation models are build based on seat working conditions.The mechanical characteristics and structure of the main components of seat suspension are analyze.The dynamic model of magnetorheological damper and equivalent force curve of air spring are established with experiment and calculation,which is the basis of dynamic model of seat suspension.Then the simulation model is built to get ready for simulation experiments.(2)The logic of three-stage control is designed based on the analysis to working requirements and vibration characteristics of seat suspension,and the logic of safe,middle and dangerous stage of three-stage control are designed respectively for different working conditions.Then,the appropriate parameters of algorithm are selected according to the seat suspension structure and working conditions.(3)According to the dynamic simulation model built,the correctness and actual effect of the third-order control algorithm are simulated and verified.The performance of the third-order control algorithm in terms of comfort,safety and comprehensive improvement is verified through fixed frequency sinusoidal excitation,bump excitation and random excitation,and the required algorithm parameters are adjusted again according to the simulation results.(4)The seat vibration experiment is conducted based on the d SPACE and vibration bench.The same fixed-frequency sinusoidal excitation,bump excitation and random excitation are used to conduct comparative experiments to analyze the performance of the third-order control under various conditions and compare it with passive and skyhook-controlled seats to study the effectiveness and superiority of the third-order control algorithm.The shortcomings are mutually confirmed with the simulation results.