Research On Magnetoelectric Relative Displacement Self-Sensing Magnetorheological Dampers

With the improvement of Magnetorheological (MR) technologies, the study andapplication of the semiactive suspension systems based on MR dampers have been paidspecial attention to. In general, a semiactive suspension system based on MR dampersmainly comprises MR dampers, springs, dynamic sensors, semiactive controller andrequired circuits. In order to make full use of the advantages of the semiactivesuspension system based on MR dampers, it is inevitable to realize the feedback controlof the semiactive suspension system with the dynamic responses of the plant. One of thepresuppositions to realize the feedback control is that the dynamic responces of theplant can be accessed, which are realized through the dynamic sensors. Up to now, thedynamic sensors aligned with the MR dampers in parallel are used to access thedynamic responces of the plant and/or across the MR dampers in the MR damper basedsemiactive suspension system, which will increase the cost of the system apparently. Inthe meantime, the separated sensors in the semiactive suspension system complicate thestructure, enlarge the installation space and need more cables and connectors.Furthermore, the separated sensors that are exposed directly into the harmful workingenvironments will be prone to be injured by collisions, water, oil and electromagneticfield, which will enlarge the size of the system and decrease the reliability. In this case,in order to realize the massive production and application of MR dampers in industry, itis urgent to simplify the structure, improve the reliability, and decrease the cost of thesemiactive suspension system based on MR dampers.We can image that it is a good idea to integrate the dynamic sensor into the MRdamper to compose an MR damper with self-sensing ability of the dynamic responses,which can not only decrease the cost but also improve the reliability with eliminationthe separate sensors and its connectors from the conventional systems. In thisdissertation, a novel approach to make MR damper self-sensing based on the magneticflux linkage measurement and the working principle of an Integrated RelativeDisplacement Sensor (IRDS) directly integrated into a commercially available MRdamper are proposed and realized. In addition, the principle and structure of aMagnetoelectric Self-Sensing MR Damper (MSMRD) are proposed and realized basedon the IRDS proposed in this dissertation. The semiactive suspension system based onMSMRDs can exclude the separated sensors, which can simplify the structure, decreasethe cost, and improve the realiability.The major research works completed in this dissertation include: 1. For the feedback control of MR dampers, the principles and pertinent structuresof two different sensing modes of the IRDS, which includes (a) the rod sensing modeand (b) the cylinder sensing mode, are proposed. According to the prelimary researchresults, the IRDS based on the cylinder sensing mode is more prone to be integrated intocommercially available MR dampers. The mathematic model of the IRDS based on thecylinder sensing mode is established in this dissertation. 2. Based on the mathematic model of IRDS based on the cylinder sensing mode,the principle of the MSMRD are proposed and realized and the method to realize thesemiactive suspension system based on MSMRDs also explored. 3. Based on the Bingham visco-plasticity model of MR fluids and the Parallel-Platemodel of MR dampers, the quasi-static model of MR damper of the MSMRD is buildand can well estimate the damping force of the MSMRD. 4. On the basis of a preliminary parameter model of the MSMRD, the harmonicmagnetic field of the IRDS and the static magnetic field of the MR damper are modeledand analyzed through the FEM (finite element modeling) and FEA (finite elementanalyzing) using the software package of ANSYS/EMAG. The analyzing results withANSYS show that not only is the integrated approach of the MSMRD validatedqualitatively, but also the structure and the main flux paths of the MSMRD are rational. 5. According to the principle of the MSMRD, the sensing model of IRDS, and thequasi-static model of MR damper, the simulation model to estimate the performance ofthe IRDS and the MR damper in MATLAB/SIMULINK are build, respectively. Somekey design parameters of the MSMRD that influence on the performance of the IRDS,the MR damper, and MSMRD are explored and determined through the abovesimulation models and a set of the optimum parameters of the MSMRD is obtained. 6. Based on the optimum parameters of MSMRD, the harmonic magnetic field ofthe IRDS and the static magnetic field of the MR damper are modeled and analyzed,respectively. Then, the finite element analysis results of the optimum parameters ofMSMRD are used as the input of the performance simulation model, which are carriedout to validate and estimate quantitatively the performance of MSMRD. The simulatingresults show that the output of the IRDS is directly proportional to the displacement ofthe piston and the relationship between the damping force and the displacement and therelationships between the damping force and the velocity validate the the damping forcemodel of the MSMRD.7. Based on the principle studying and the simulation validating of the MSMRD,the MSMRD prototype is developed. In order to experimentally validate theperformance of the IRDS, a testing setup for the IRDS is build using MTS 849 vibrationtest system and the dSPACE rapid prototyping system. The experimental results indicatethat the principle of the IRDS is feasible. 8. The nonlinearity of the IRDS of MSMRD is explored and two linearcompensating methods are proposed. The research works in this dissertation establish the theoretical foundation tosimplify the structure, decrease the cost, and improve the reliability of the semiactivesuspension system based on MR dampers. Furthermore, the MSMRD proposed andrealized in the dissertation possesses a cheerful prospect in industry.