Real-time sensorless estimation of position and force for solenoid actuators

In various fields, small actuation systems are required to aid human activities in a narrow space and to realize fine motions. Although some miniature actuators have been developed, the size of the sensors attached to them prevents the miniaturization of the systems. In this paper, a sensorless actuation system with a compact solenoid actuator is proposed. An input signal including the AC and DC components is used. The inductance and position are estimated from the AC component. The DC component is applied in order to drive the solenoid actuator. Simulations and experiments concerning frequency characteristics and simultaneous estimation are conducted to verify the validity of the proposal. From the results of the frequency characteristics, the position and force estimation are accurately achieved up to 10Hz frequency. As a result of the simultaneous estimation, the position and force are simultaneously estimated in real time. This proposal is useful, because a small solenoid actuation system whose position and force are simultaneously estimated in real time without the need for any position and force sensors is realized.