Torque control of electrorheological fluidic resistive actuators for haptic vehicular instrument controls

Force-feedback mechanisms have been designed to simplify and enhance the human-vehicle interface. The increase in secondary controls within vehicle cockpits has created a desire for a simpler more efficient human-vehicle interface. By consolidating various controls into a single, haptic feedback control device, information can be transmitted to the operator, without requiring the driver's visual attention. In this paper the experimental closed loop torque control of electro-rheological fluids (ERF) based resistive actuators for haptic applications is performed. ERFs are liquids that respond mechanically to electric fields by changing their properties, such as viscosity and shear stress electroactively. Using the electrically controlled rheological properties of ERFs, we developed resistive-actuators for haptic devices that can resist human operator forces in a controlled and. tunable fashion. In this study, the ERF resistive-actuator analytical model is derived and experimentally verified and accurate closed loop torque control is experimentally achieved using a non-linear proportional integral controller with a feedforward loop.