Method of estimating and compensating interference torque of lifting system

A method of estimating and compensating an interference torque of a lifting system applied to a motor for driving the lifting system, the motor configured to drive a traction wheel to rotate, and a wire rope across the traction wheel configured to drive an elevator car to move upward and downward in a hoistway, the method of estimating and compensating the interference torque comprising steps of:

• (a) continuously integrating a speed of the motor and performing an absolute value calculation to an integration value obtained from the integration of the speed of the motor if the integration value is negative when the elevator car moves upward and downward between a top and a bottom of the hoistway from an initial position to acquire a maximum travel position of the elevator car in the hoistway, (b) estimating a rope load constant of the wire rope according to the initial position and the maximum travel position when the motor operates at a constant speed, and calculating a rope load torque according to the maximum travel position, the rope load constant, and a present position of the motor, (c) estimating a car and counterweight load torque according to a car weight of the elevator car and a counterweight weight when the motor operates at a zero speed, and (d) estimating an interference torque and performing a feedforward compensation applied to the motor for driving the lifting system based on the interference torque according to the rope load torque and the car and counterweight load torque.