Dynamic behavior of a trolley traction system with a flexible driving rope

The rope traction driven trolleys are widely used in modern port machineries especially on the quayside cranes since it has so many benefits compared with a self-driving system. However, the system is more complex for automatic control since: (1) the system has different mass distribution varies according to different load cases; (2) the rope´s equivalent stiffness depends on the current position of the trolley. In this paper, kinemics and dynamic model of the trolley traction system considering the interaction between the trolley position and the stiffness of the system are put forward. Several numerical experiments based on the system´s model considering the influence of trolley positions and payload weights are tested. The results indicate the great influence in stiffness and mass of the system are greatly changed during operation. A controller with scheduled gains adjusting gains in both position and velocity circle to the most suitable according to current payload weight and trolley position is introduced and tested. The behavior shows the effectiveness of the controller with scheduled gains.