Model-based control design techniques for small systems using low-power microcontrollers

The primary purpose of the following considerations is the model-based control design of mechatronic systems. The focus of our work is the utilization of these techniques by developers, which are normally afraid of doing the model-based approach because of increased time consumption in early development stages, unsatisfying or missing hardware support within design tools, or the assumption of inefficient code from automated code builds. This paper will therefore show the usage of model-based design techniques, including automatic code generation, for applications using small 8-bit microcontrollers with limited computing power and memory. Initially, the used concept for the code generation is discussed in detail, which is the key issue for model-based design methods. To show the efficiency of this approach, an industrial application [1] is designed by using this model-based method. This application will realize a breathing air conditioning device, which will be used for medical and training purposes to simulate high altitude air conditions. It will use a fuel cell to adjust the percentage of oxygen for special conditions. To achieve this goal, the application will require special control algorithms which are different from those control algorithms usually used for fuel cells. One of the key aspects is the required reduction of hydrogen consumption. The heat and electrical power generated by the fuel cell are used to heat the breathing air and to supply the electronic circuits with electrical power. Especially the control algorithms have to be designed for robustness and safety due to the used hydrogen. Usage of a model-based approach for this purpose will allow early testing of the designed control algorithms including boundary tests which are not possible or dangerous with the real system.