Research On Design And Control Of Small-size Multi-degree-of-freedom Vibration Isolation Platform Based On Magnetorheological Dampe

Nowadays,vehicle-mounted equipment such as vehicle-mounted medical equipment,vehicle-mounted imaging equipment,and geological exploration equipment are becoming more and more miniaturized and refined,which requires higher and higher stability for the transportation environment.However,there are still many karst landforms in China,such as Guizhou and Yunnan,and their road conditions are more complicated.Vibration and shock from the ground will affect the accuracy and life of vehicle-mounted equipment.In addition,in recent years,magneto-rheological damper(MRD)is more and more widely used in aerospace,bridges,biomedical and other fields,because of its variable damping characteristic,stable structure,fast response speed,and low energy consumption.Therefore,this paper uses its variable damping characteristic to design a small-sized multi-degree-of-freedom vibration isolation platform based on MRD for the protection of vehicle-mounted equipment.The main research contents are as follows:In this paper,Gaussian white noise is used to construct the road surface input model of the D-level road surface.The vibration shock of the vehicle-mounted equipment of the driving vehicle mainly comes from the vertical motion of the vehicle and the pitch angle motion of the vehicle body.Therefore,the theoretical model and simulation model of the 1/2 vehicle are established.The road input model is used as the excitation signal to obtain the vehicle’s vertical motion and pitch angle motion,which are used as the excitation signal of the vibration isolation platform.Based on this,a semi-active vibration isolation platform with small size and compact structure is designed,and a dynamic simulation platform is constructed using Solidworks&Matlab,which lays the foundation for the research of motion control algorithms in the following text.In order to explore the dynamic characteristics of MRD,this paper designs and builds the external characteristic test platform of linear and rotary magneto-rheological dampers.Then,collect the test data by using NI acquisition technology.Processe the data by filtering,phase addition,etc.And then,use Matlab/Simulink to construct the Bouc-wen model of MRD,and explore the physical meaning of each parameter in detail.Based on this,the parameter identification of the Bouc-wen model is completed by using the least square method,and the simulation model of the MRD is obtained,which paves the way for the research of the motion control algorithm.Based on the designed vibration isolation platform model and MRD model,this paper designs a switch-type shyhook controller,which has simple structure,fast response speed and good stability.But it is prone to jitter in the high frequency band.Therefore,based on the idea of equivalent shyhook,this paper designs a continuous equivalent shyhook fuzzy controller by introducing fuzzy control to improve this shortcoming.In addition,since there are two different MRDs,this paper normalizes the input of the fuzzy controller,which improves the generality of the fuzzy controller.Finally,through simulation comparison and analysis,compared with passive dynamic vibration isolation,the vibration isolation effect has been significantly improved,and the fuzzy control can effectively suppress the high frequency band of the excitation,which is better than the switch-type shyhook control.