An Active Disturbance Rejection Control Study Of Crane Control

Overhead crane system is a kind of nonlinear, strongly coupled, underactuation system. It is difficult to control the system which requires that goods are carried to the designated location quickly and minimizing the swing angle of the load. It is also required that the system should resist wind and friction disturbance. Another problem in the system is that the length of the rope and the quality of the load will change while the system is operating, which leads to changes in parameters of the model.Firstly, the thesis regards the overhead crane as the controlled object and builds the model of it, taking the disturbance factors into consideration. Now crane system is often analyzed by the input shaping method. The substance of suppressing swing angle is concluded through theoretical derivation that the input shaping controller introduces a feedforward controller to offset the oscillation. So a PID controller with a pole-zero cancellation is proposed which is compared with input shaping method.According to the characteristics of the controlled object, load position feedback control scheme and trolley position feedback control scheme are proposed. A fourth-order ADRC(Active Disturbance Rejection Control) is designed based on load position feedback control scheme. Considering the restrictions of the experimental platform, the fourth order ADRC platform experiment is difficult to achieve, so an easier achieved second-order ADRC is designed while 0b is increased and the higher order terms are viewed as a disturbance. Then a second order ADRC is designed based on the trolley position feedback control scheme. The simulation results show that the ADRC controller is more efficient, then the ADRC scheme is compared with the input shaping scheme.Finally, the experimental system of the overhead crane is designed, which the swing angle measuring device is completed with the industrial camera and OpenCV method, the measurement frequency is up to 50 frame/s or more. The test results of the overhead crane show that the ADRC has advantages in such control systems.