Research On Self-powered And Self-sensing Magnetorheological Damper

With the growing popularity of vehicle in modern society, higher requirements of vehicle driving comfort and handling stability are put forward. As a smart damping device, more and more attention are paid on magnetorheological(MR) damper for its advantage of fast response, compact structure, wide adjustable damping force in automotive semi-active suspension vibration control research. However, Damping force generated by the MR damper need external magnetic field, while the external magnetic field is excited by the current. If the vehicle battery is used to power the MR damper, additional wiring is needed, resulting in the reduction of system reliability. At the same time, four MR dampers in the suspension could cause a lot of energy consumption during the long running process. In order to solve the energy supply problem, improve the reliability of the magneto-rheological damper, MR damper requires self-powered function. Simultaneously, as an intelligent control system, MR damping system need to have the ability to perceive its own dynamic vibration information, to provide the motion parameters for intelligent control. Vibration information of MR damper is necessary to be acquired to achieve the function of intelligent control for MR damping system. The dynamic vibration information of controlled object is the relative displacement, velocity and acceleration between the cylinder and the piston rod of MR damper. This paper takes self-powered and self-sensing technology for MR damper in the field of vehicles as the background. A vibration energy harvester based on disc permanent magnet generator drove by ball screw is proposed. Based on the linear relationship between the electrical signal and the relative speed for the cylinder and the piston rod, the self-sensing performance damping system is studied, revealing The changing rule of damping force for MR damper under self-powered is revealed. Deep theoretical difficulty and practical significance are contained in this research. The solution of the problem will provide theoretical guidance for long-term reliable operation of MR damper in MR damping system. It will also provide technical foundation for the magneto-rheological technology application. The main content includes followings:(1) Literatures are reviewed.The background and significance of the research is also illustrated.This paper points out the important research significance of MR damper equipped with the function of self-powered and self-sensing. The paper describes three ways of vibration energy harvesting. The research status of domestic and international scholars about achieving self-powered self-sensing function for MR damper is discussed, and the problem in the research is also analyzed.(2)The vibration energy harvester is designed.The dimensions of the disk generator are determined.The basic electromagnetic relation is studied.To solve the self-powered problem for MR damper in MR damping system, a vibration energy harvester based on disc permanent magnet generator is proposed and ball screw is selected as the motion conversion mechanism. The key structure dimension of the disc permanent magnet generator is determined. The magnetic circuit is designed. The formula for calculating back electromotive force is derived.(3)The electromagnetic simulation model of the disk generator is established to analyze its power performance.The electromagnetic simulation model of the disc permanent magnet generator is established by Maxwell 3D software. A rectifier and filter circuit is designed. The load characteristics, no load characteristics and electromagnetic counter-force performance are analyzed under constant rotation speed excitation and harmonic excitation.(4) The self-powered and self-sensing testing system is established for performance verification.According to the dimension parameters of vibration energy harvester based on disc permanent magnet generator and MR damper, the prototype of vibration energy harvester and MR damper are fabricated. The test system based on the MTS is established to test the MR damping system performance, including self-powered performance of vibration energy harvester, self-sensing performance and the size of the controllable damping force. Proposed based on the output voltage of the envelope of self-sensing solutions.(5)A self-sensing solution based on the envelope of the output voltage is proposed.Based on the linear relationship between the the electrical signal and the relative speed among the sprung mass and the unsprung mass, a solution to acquire relative speed based on the envelope of the output voltage is proposed. The self-sensing performance of the disc generator is evaluated.