Variable Torque Transmission Control Utilizing Movement of Magnetic Fluid : 3rd Report, Torque Control under PWM and Fuzzy Reasoning

This paper describes the characteristics of torque transmission in a magnetic fluid coupling when a magnetic field is controlled under the PWM (pulse width modulation) and the fuzzy controller. Whenever a magnetic field is applied to a fluid coupling, the magnetic fluid shifts to the outer area of the rotating disk, and a torque is transmitted through the viscous friction of the magnetic fluid between the disk and the case. The output torque is changed by the PWM controller that determines an amount of electric current to the coil at a high velocity of the rotating disk. Since the relation between the duty ratio of the applied voltage to the coil and the output torque is nonlinear, fuzzy controller is used to get a desired torque. It is confirmed experimentally that the output torque can be controlled under the PWM and the fuzzy controller. This system is also valid for the disturbance of temperature.