A Hardware/Software Co-Design Approach for Control Applications with Static Real-Time Reallocation

The reliability of a system can be increased by redundancy. With redundancy, faults can be detected through comparison and failing components can be replaced. In order to avoid the verification of different implementations, the creation of redundant components from a single source is beneficial. In this paper, we propose a hardware/software (hw/sw) co-design approach for control applications that target a hardware platform based on the Xilinx Zynq-7000. Our approach contains a tool chain that allows to generate the software task, as well as a hardware accelerator from the same controller model. Moreover, it includes an architecture which allows to switch between the two implementations while maintaining soft real-time constraints. The hardware accelerator can be instantiated multiple times and the software task can be started on multiple processor cores in order to increase the redundancy. We evaluated our approach with a closed-loop controller in a process automation scenario, in which the water of a tank is kept at a constant level. We show, that redundancy can be added with only little effort during development time as well as runtime, and that the control mechanism is not influenced by dynamic reallocation.