Command shaping for vibration reduction of container cranes.pdfVIP

2012 12th International Conference on Control, Automation and Systems Oct. 17-21, 2012 in ICC, Jeju Island, Korea 1. INTRODUCTION Container cranes (or quay cranes) are used for vessel-to-truck and truck-to-vessel loading and unloading of containers at container terminals. Container cranes consist of a supporting structure called the gantry that can traverse the length of a quay or yard, a trolley, and a moving gripper called a spreader. The trolley runs along rails, which are located on the top or sides of the boom, transferring containers to or from the ship. The spreader can be lowered on top of a container, and locks on to the containers four locking points by means of twist-lock mechanisms. The container is then lifted and transferred onto a truck, which takes the container to a storage yard. The crane also unloads containers from the truck and transfers them to the ship. Cranes normally transport single containers; however, some new cranes are capable of loading/unloading up to four 20-foot containers at once. Since the movement of the trolley sways the container during transport, the main issue in container crane control is quick suppression of the vibrations caused by trolley motions at the trolley’s goal position. Additionally, a residual sway, due to crane dynamics and disturbances such as winds, occurs at the end of the trolley’s movement. Thus, researchers working in the area of container crane control always have been obliged to deal with sway suppression. Container oscillation and the obligation to suppress it, in fact, constitute a transportation bottleneck headache for container terminal officials. Although the container crane is a special case of many types of cranes, early crane control results are still relevant to the present concern. Feedback control methods and algorithms have been applied to crane systems [1-8]. These algorithms need to measure the sway angle. Normally, an industry camera detects marker