Cranes are machines that can be used to move or lift heavy objects to a wide variety of heights. Because of these capabilities, cranes are frequently used in harbors, where the loading and unloading of containers demand that the they are placed on the top of each other from above as precisely as possible. They are also very useful at construction sites, where building materials need to be lifted on top of high-rise buildings.
During the movement of the crane the swinging of the load can be dangerous to both the cargo and its environment. For precise movements, swinging must be minimized, but if done manually, it is very time-consuming, and it also requires that the crane operator is highly skilled. For time-efficient work, some kind of controller is necessary.
During my thesis semester, I had access to a laboratory crane model which could be moved in a vertical two-dimensional plane using a Quarc rapid prototyping system. My project was to design speed and position controllers for the vertical and horizontal directions in the Matlab-Simulink environment, and comparing these controllers in terms of ergonomics, speed and precision. In order to assist the work of the operator a swing dampening system has also been implemented, with which the oscillation time can be reduced to one-hundredth.