Sensorless load and position estimation in linear reluctance actuator

Sensorless load and position estimation of linear reluctance actuator is investigated in this paper. Due to wide application of these actuators in several industrial automation systems, sensorless techniques are significant to decrease the cost of the system and increase the reliability in the closed-loop control systems. In this paper, based on dynamic model of the actuator and the characteristics of its subsystems, the possibility of sensorless estimation of mechanical parameters is explored. Considering nonlinear behavior of magnetic subsystem, the position of the plunger could be estimated based on the winding inductance and the excitation current value. Then, the amount of load force could be determined based on current value and estimated position. Laboratory measurements of the actuator’s characteristics assist in increasing the accuracy of estimation besides dynamic modeling.