Research On RTOS-Centric Platform-Based Design For Embedded System

In recent years, with increasing needs and demands, embedded systems are becoming more and more complicated, large-scale and smart, and have many constraints which always conflict with each other, such as features, performance, power and cost. How to make a good balance among different requirements and constraints is a great challenge of embedded system design in the future. Corresponding to this challenge, Platform-Based Design (PBD) is an appropriate method to make a trade-off among different requirements and constraints. Platform-based design is a system level design methodology where the core one hand is the programmability and reusability in both software and hardware to guarantee the flexibility for different applications, the other hand is the hardware/software co-design to optimize the design. For real-time and small-to middle scale embedded systems, the Real-Time Operating System (RTOS)-centric platform based design is a more appropriate approach. In this thesis, a detailed research on it is presented. A hardware&software all programmable rapid protype platform for small-to middle-scale embedded system is constructed above on Toyobashi OPen Platform for Embedded Real-time System (TOPPERS), and applied in different fields such as motion control system, instrument and meter and mobile robot. The main contributions of this thesis are as follow.As the core and base of platform based design in this thesis, the features of RTOS such as performance, memory footprint, and scalability have a great impact on the whole platform. A detailed qualitative and quantitative evaluation of representative open source RTOSs is presented. The differences, advantages and disadvantages of selected RTOSs are discussed. The key criterias of RTOS and the corresponding benchmark methods are also proposed, and are useful for the selection, application, design and improvement of RTOS. Through evaluation and comparison, TOPPERS is chosen as the core and base,The details of RTOS-centric platform-based design are researched. A hardware and software all programmable rapid protype platform is proposed and implemented. In hardware, this platform has hybrid architecture of processor-programmable logic; In software, this platform is constructed on TOPPERS software components. An RTOS-centric hardware/software co-design approach is also proposed for this platform, including the construction of a hardware/software co-simulation environment. The evaluation results and the real application show that this platform is all programmable in hardware and software, and makes a balance among cost, features and performance.As a specific application of the previous platform, a Hybrid Real-time Mobile Robot Platform (HRMRP) is proposed and has the features of hybrid, real-time and component. There are3layers in HRMRP, data layer for sensors and actuators, real-time layer for real-time control of mobile robot’s behavior, and high performance layer for more advanced and complex operations. In hardware, the performance of core devices is enhanced; In software, more middlewares are designed and the adoption of Robot Operating System (ROS) makes the platform more complete for mobile robot application.Finally, for more complex high-end embedded systems, we propose the corresponding improvements based on a heterogeneous multi-core all-programmable System on Chip (SoC). Although the constraints on power and cost are loosen, the improvements on features, performance and flexibility are obvious. The dual-OS virtualization of RTOS and General-Purpose Operating System (GPOS) in multi-core system is implemented. The RTOS and GPOS are isolated from each other through hardware security mechanism, so the functionality of GPOS and the real-time and reliability of RTOS are guaranteed together.