Real-time position sensorless estimation of position and force of solenoid actuator for haptic devices

Haptic devices are receiving a lot of attention, especially in robotics and medical field. Position and force of actuators are needed to communicate the haptic information. This paper aims to realize sensorless estimation of position and force of solenoid actuators for haptic devices. The simultaneous estimation of position and force is conducted by applying DC and superposed AC voltage to the solenoid actuator. From the DC signals, the force is estimated. From the AC signals, the position is estimated. Experiments of the estimation were conducted to validate this proposal. The proposal succeeded in realizing high precision position estimation with an accuracy of 50 μm. The simultaneous estimation of the position and force was accurately achieved in real time. This technique is useful, as the application field of the solenoid actuators is enhanced.