Temperature estimation of lead screw drive using disturbance observer for sensorless force control

This study proposes a sensorless force control system and temperature estimation of lead screw drive systems. A control system for a lead screw drive is designed easily based on a simple mathematical model due to the simple structure. Therefore, lead screw systems are suitable for low-speed range applications, such as force control. A sensorless force control system is proposed for a lead screw drive system with friction compensation based on the approximated hyperbolic function. The performance of the sensorless force control method is verified by experiments. In addition, this paper proposes temperature estimation method for fine force control. The stick-slip phenomenon occurs on the lead screw due to frictional heating by the lead screw driving. Force estimation error is increased due to change of the frictional properties of the lead screw, that is confirmed by the experiments in this paper. Therefore, the proposed method estimates the temperature of the lead screw using the estimated vertical force between lead screw and nut based on the reaction force observer. The proposed method realizes fine force control of the lead screw driving system. The validity of the proposed method is verified by a comparison of numerical simulation results and experimental results.