Patent ID: 7424937

Claim:
A method for estimating a torque/force exerted by a load against an actuator driven by an electric motor against the load, wherein the method comprises the steps of: a) measuring motor current of the electric motor; b) calculating a motor torque/force of the electric motor from the measured motor current; c) measuring a position/angle or speed/angular speed of the actuator when the actuator is driven by the electric motor to engage the load; d) calculating an actuator-experienced torque/force due to the electric motor and the load from the measured position/angle or the measured speed/angular speed using a mathematical model of the actuator without calculating a difference between the measured position/angle or the measured speed/angular speed and an estimated position/angle or estimated speed/angular speed of the actuator derived from using at least the calculated actuator-experienced torque/force; and e) calculating the torque/force exerted by the load against the actuator using at least a difference between the calculated motor torque/force and the calculated actuator-experienced torque/force.