CHAPTER 15: Magnetorheological Devices with Multiple Functions

This chapter is focused on the magnetorheological (MR) fluid devices with multiple functions, including linear dampers and rotary actuators. The benefits of functional integration of linear MR dampers are introduced. Novel self-sensing MR dampers with power generation are proposed to integrate the dynamic sensing, MR damping and power generation functions. Concepts and key issues for integrating multiple functions are presented. Methods applicable for integrating MR dampers with multiple functions are discussed. The structure design, principle, and modeling for the proposed multifunctional MR damper are presented, with the discussions on the magnetic field interaction. Results show that the self-sensing MR damper with power generation can perform several functions simultaneously. In addition, a multifunctional rotary actuator is also proposed to integrate the motor/generator part with MR fluid into a single device. The actuator could function as motor, generator, clutch and brake, with compact size and less power consumption. In the condition of limited working space, it would be desirable to have a single device with multiple functions, instead of several separate components. The finite element method is utilized to analyze the magnetic circuits, influence of permanent magnets on MR fluid and magnetic flux distribution. Different inner coils, in the form of interior, exterior and axial, are considered. A prototype is then fabricated and each function of the developed multifunctional actuator is tested. The results show that the developed actuator would be beneficial to applications that favour multiple functions with compact size.