Design And Validation Of Relative Displacement Self-Sensing Magnetorheological Damper Based On Electromagnetic Induction

Magnetorheological (MR) dampers are considered to be useful in many fields. However, in order to make full use of the advantages of the semiactive suspension system based on MR dampers, it is inevitable to realize the feedback control with the dynamic responses of the plant. One of the presuppositions to realize the feedback control is that the dynamic responces of the plant can be accessed, which are realized through the dynamic sensors. Up to now, the dynamic sensors aligned with the MR dampers in parallel are used to access the dynamic responces of the plant and/or across the MR dampers in the MR damper based semiactive suspension system, which will reslut in the following problems: (1) complicating the system, (2) enlarging the installation space, (3) increasing the cost, and (4) increasing the mass. In the meantime, the separated sensors that are exposed directly into the harmful working environments will be prone to be injured by collisions, water, oil, and electromagnetic field, which will decrease the reliability to some extent. In this case, in order to realize the massive production and application of MR dampers in industry, it is urgent to simplify the structure, improve the reliability, and decrease the cost of the semiactive suspension system based on MR dampers.We can image that it is a good idea to integrate the dynamic sensor into the MR damper 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 elimination the separate sensors and its connectors from the conventional systems. In this dissertation, an integrated relative displacement sensor (IRDS) technology to make MR dampers self-sensing based on the electromagnetic induction and the working principle of an integrated relative displacement self-sensing MR Damper (IRDSMRD) based on the IRDS technology are proposed and realized. On this condition, an IRDSMRD is designed. The semiactive suspension system based on IRDSMRDs can exclude the separated sensors, which can simplify the structure, decrease the cost, and improve the realiability.The major research works completed in this dissertation include:1. According to the integrated sensory technology for linear MR dampers, the mathematic model of the IRDS based on electromagnetic induction is established for the feedback control of MR dampers. 2. On the basis of the mathematic model of IRDS based on electromagnetic induction, the principle of the IRDSMRD are proposed and realized and the method to realize the semiactive suspension system based on IRDSMRDs also explored.3. On the basis of a preliminary parameter model of the IRDSMRD, the transient magnetic field of the IRDS and the static magnetic field of the MR damper are modeled and analyzed through the FEM (finite element modeling) and FEA (finite element analyzing) using the software package of Ansoft/Maxwell 2D. The influences of the key structural parameters, the frequency of the carrier of the IRDS, and the magnetization of AC and DC supplies on the damping and sensory performance of the IRDSMRD are analyzed and a set of the optimum parameters of the IRDSMRD is obtained.4. Based on the optimized parameters of the IRDSMRD, the damping and sensory performance of the IRDSMRD are predicted. The research results indicate that the function of the relative displacement sensing property can be integrated into MR dampers. Furthermore, the IRDSMRD designed in this dissertation possesses the large controllable damping ratio and the good relative displacement sensing performance utilizing the IRDS technology proposed in this dissertation.5. An IRDSMRD prototype is developed and a testing setup for the IRDSMRD is build using PLS-10 vibration test system and the dSPACE prototyping system. The influences of the frequency of the carrier of the IRDS, the frequency of the external vibration and the magnetization of AC and DC supplies on the sensory performance of the IRDS are tested and a set of the values of the IRDSMRD damping force is obtained. The experimental results validate the principle of the IRDSMRD and the simulation results.The research works in this dissertation establish the theoretical foundation to simplify the structure, decrease the cost, and improve the reliability of the semiactive suspension system based on MR dampers. Furthermore, the IRDSMRD proposed and realized in the dissertation possesses a cheerful prospect in industry.