Many of today's Embedded Systems are used to run multiple control applications, each in charge of stabilizing one closed loop system (plant). Usually, the designer selects, designs and assigns one dedicated controller for each plant - i.e., each plant is managed by one and the same controller all the time.
In contrast to this usual approach, however, the developer might choose to design (and implement) more than one control algorithm per individual plant and switch between them during runtime - depending on the current state of the respective plant. The aim of such a switched system is to improve both the overall control performance (e.g., by temporarily switching to a high-end controller during a disturbance) and the efficiency of the Embedded System (e.g., by avoiding unnecessarily complex control calculations whilst all plants are in steady-state).
To investigate the impact of this approach on "real-world control loops", a test setup based on a Levitating Ball is being developed.

The goal of this thesis is to evaluate (at least) two different controllers for a Magnetic Levitating Ball (plant) on an FPGA-System (featuring a Xilinx Virtex 5). The plant is already interfaced to the FPGA-System which allows reading the sensor (a light barrier) and writing to the actuator (a magnetic coil). First of all, a simple software PID controller will be implemented (on a Xilinx Microblaze CPU) to familiarize with the FPGA platform and to characterize the plant. Based thereon, additional controllers are implemented and compared against each other. To speed up the implementation, Matlab Coder and HDL Coder can be used. Finally, an evaluation of the "switched controller" approach is performed to identify the up- and downsides of the approach.