Application of Independent Joint Control Strategy for Discrete-Time Servo Control of Overhead Cranes

In this study, a new servo control system is presented for the overhead crane based on discrete-time state feedback approach. It provides both robust tracking and load swing suppression. Inspired from independent joint and computed torque control in robot manipulator field, a new model is derived in which the crane actuators are considered as the main plant. The crane nonlinearities are then treated as disturbances acting on each actuator and being compensated via feedforward control. The load swing control is integrated to the servo controller through modifying the reference trolley acceleration. The stability of the tracking error and swing dynamics are proven based on error dynamic equation and passivity theory. Experimental results indicate the high performance and great potential for industrial application of the proposed control system.