Cranes and other types of weight handling equipment are used to carry heavy loads. In many cases, the load is attached to the mechanical structure with a rope, so the load position cannot be directly actuated and the resulting oscillatory behavior may present serious difficulties to inexperienced human operators. The weight handling problem can be solved automatically by a computer, which calculates the reference trajectory between the desired initial and final points first, then controls the transportation procedure itself. The topic of this thesis is the development and implementation of a tracking controller for two-dimensional overhead cranes.
A possible way to control non-linear systems is the use of exact linearization and the application of a tracking controller to ensure exponential decay of the error along the reference trajectory. In case of overhead cranes, it can be used if the load coordinates are known which is not the case in real applications, where the motor axis displacements are usually measured. This thesis applies the linearization techniques such that the calculations of unmeasured states are realized with an observer, which is constructed for the linear approximation of the dynamics along the reference trajectory.
After the controller design process, simulation results are provided to prove the applicability of the concept. In the second part of the thesis, the theoretical results are implemented and tested on a laboratory equipment of the Intelligent Robots Laboratory at BME.