Design And Experiment Of MR Fluid Based SBW Force Feedback Device

Steer-by-wire(SBW) system is a technology that steering wheel and the front wheels connected by a control signal instead of the conventional mechanical interface. Because the lack of direct mechanical linkage, the feedback force from the road surface and the force generated by the tire incentives cannot be passed directly to the steering wheel. Therefore, SBW system requires a specific device, connecting with the steering wheel, to achieve simulation of road feel and the function of steering self-returnability.The present majority of SBW force feedback systems consist of DC motor with the reducing mechanism. But DC motor often have large size after matching reducing mechanism, and also have other insufficiencies, such as obvious rigid impact at work, high energy consumption. In this paper, a kind of magneto rheological(MR) fluid based rotary damping device is presented in order to solve these problems, and to realize the force feedback function in SBW system. Based on the previous studies, magneto rheological device can better meet the actual engineering requirements of SBW system, due to its characteristics of sensitive reaction, smooth operation and wide torque adjustable range. The main work of this dissertation including the following aspects:① On the basis of mechanical steering system, the feedback torque of conventional steering system was analyzed. The mathematical model of feedback torque was established according to the structure parameters of a vehicle. The relationship between the front wheel and feedback torque of steering wheel was obtained using numerical simulation. A MR based SBW system force feedback device was raised.② A MR force feedback(FFB) device, which utilizing both the side and the end surface of the rotor, was designed based on the requirements of Steer-by-Wire(SBW) system. According to the single-type mode, the hybrid-type torque model and the design method of magnetic circuit and structure were proposed.③ According to the basic law of magnetic circuit, magnetic circuit model of hybrid-type was established. By using the finite element software ANSYS, the validity of theoretical design method was verified, and the influence factors of hybrid-type mode torque were studied. The main structure parameters of FFB device was optimized by the APDL parametric design language.④ The mechanical structure of FFB device was designed. The design ideas and selection methods of the main components were introduced, including the overall layout. According to the test requirements, the experimental platform of force feedback device has been design. The FFB device’s hysteresis phenomena, torque-speed characteristic and dynamic performance were tested using force feedback experimental platform. Experimental results show that FFB device can be used in SBW force feedback system. The experimental system can be used for further research on control algorithm.