Closed-Loop-Based Self-Adaptive Hardware/Software-Embedded Systems: Design Methodology and Smart Cam Case Study

摘要

This article presents our methodology for implementing self-adaptivness within an OS-based and re-configurable embedded system according to objectives such as quality of service, performance, or power consumption. We detail our approach to separate application-specific decisions and hardware/software-implementation decisions at system level. The former are related to the efficiency control of applications and based on the knowledge of application engineers. The latter are generic and address the choice between various hardware and software implementations according to user objectives. The decision management is implemented as an adaptive closed-loop model. We describe how each design step may be implemented and especially how we solved the issue of stability. Finally, we present a video-tracking application implemented on a FPGA to demonstrate the effectiveness of our solution, results are given for a system built around a NIOS soft-core with μCOS II RTOS and new services for managing hardware and software tasks transparently.