Mathematical description and control design for the simultaneous levitation and propulsion of a conveyor vehicle

Magnetic levitation is still an important issue for industry and research. Wherever high dynamics, position accuracy, high reliability and low mechanical wear are required, magnetic levitation is an effective alternative to conventional technologies. Conventional systems with mechanical guiding have shown to be limited in speed. For transporting goods over long distances, levitation can thus lead to a significant saving in time and cost. This paper describes a control design for an autonomous magnetically levitated conveyor vehicle with a linear direct drive for propulsion. Based on a mathematical description as a 2-rigid-body system with elastic coupling in torsion, a simulation environment for the vehicle is created. After that, a degree-of-freedom control is designed for the levitation operation, whereas a conventional PI control is used for the propulsion. This control design is based on the representation of the system as a 2-body system as well. The combination of control and simulation environment offers the opportunity for extensive testing and optimization before the control is applied to a test bench. By intensive analysis the stable and efficient operation of the vehicle is determined. An assortment of measurement results is presented and discussed in this paper.