Control study with a pilot crane

The pilot crane and its instrumentation are briefly introduced. The crane offers a uniform environment for a complete control engineering design starting from modeling and ending with tuning of different controllers. The potential possibilities of the crane environment for practical education of control engineering are described. The modeling issues are considered, and different identification methods are compared. Different control algorithms are applied to the load transfer in the pilot crane. The experiments show that the controllers must adapt automatically to the rope length. The velocity-controlled crane, which is a standard in industry, is the focus of the discussion. An illustrative open-loop minimum-time control is derived for the load transfer. A simple root-locus method is used to tune a cascade type of PID controller, which works satisfactorily with fixed rope length. Different pole-placement methods suffered from sensitivity and robustness problems. Good results are achieved after ill-conditioning is understood and avoided. As an example, an adaptive pole-placement control law which was tested successfully is provided. >