单片机类毕业论文设计-英文翻译.doc

河南科技大学本科毕业设计（论文）单片机类毕业论文设计英文资料翻译A modeling-based methodology for evaluating the performance of a real-time embedded control systemKlemen Perko, Remy Kocik, Redha Hamouche, Andrej TrostABSTRACTThis paper presents a modelling-based methodology for embedded control system (ECS) design. Here, instead of developing a new methodology for ECS design, we propose to upgrade an existing one by bridging it with a methodology used in other areas of embedded systems design. We created a transformation bridge between the control-scheduling and the hardware/software (HW/SW) co-design tools. By defining this bridge, we allow for an automatic model transformation. As a result, we obtain more accurate timing-behaviour simulations, considering not only the real-time software, but also the hardware architecture’s impact on the control performance. We show an example with different model-evaluation results compared to real implementation measurements, which clearly demonstrates the benefits of our approach.© 2011 Elsevier B.V. All rights reservedKEY WORDS: Modeling, Model transformations, Embedded control systems design, Real-time systems1. IntroductionEmbedded control systems (ECSs) are ubiquitous nowadays. They are used in a broad spectrum of applications, from simple temperature control in household appliances to complex and safety–critical automotive brake systems or aircraft flight control systems. Different applications have different demands with regards to the real-time execution, control performance, energy consumption, price, etc., of the ECS being used. Modern technologies for hardware (HW) and software (SW) design provide a variety of possibilities for designing ECSs (e.g., distributed and networked HW, multi-processor systems, a variety of SW control algorithms and real-time operating systems (RTOSs), etc.) [1]. It is commonly acknowledged that the designing and verifying of reliable and efficient ECSs for a particular application are challenging tasks.1.1. Traditional control-system designThe aim of designing an ECS is to build a computing system that is able to control the behavior of a physical system, e.g., a plant. Such a plant is made up of interconnected mechanical, electrical and/or chemical elements. A typical ECS consists of electronic sensors for data acquisition from the plant, a computing system for processing the control algorithm, and electronic actuators to drive the plant.The ECS design process involves different actors and areas of expertise (control theory, signal processing, real-time SW and HW engineers). Each of these engineers is familiar with their own modeling languages, models, design tools, etc. This heterogeneity introduces cuts in the design process. Model transformations are needed between each design step; however, they are often carried out manually and, as a result, are prone to mistakes and subject to interpretation, which of course depends on the skill of the designer. The traditional form of ECS design is performed in two separated domains – the control SW domain and the HW domain – using specific design tools and their respective system models. In the first domain, control engineers define the control laws and the SW engineers write the code that executes the operations required by the control laws. A so-called control-scheduling co-design is performed. Decisions made in the real-time (RT) software design affect the control design, and vice versa. For instance, different SW scheduling policies have different impacts on the latency distributions in the control loops and, consequently, on their performance. Also, the control-loop performance directly affects (by constraining) the SW execution parameters (i.e., sampling periods, task-execution jitter, etc.).In the second domain the HW engineers design an HWplatform that will execute the control SW. The connections of all the sensors and actuators to the platform are made via the available communication channels. However, because the HW platform is designed separately, control engineers cannot estimate its impact on the control-loop performance. For instance, the data from sensors and to actuators can pass through one or more communication channels. A HW engineer can, in general, choose from among a variety of communication protocols, and each type introduces different latencies and jitter, which therefore affects the SW execution. The control engineer cannot, however, evaluate the effect of these latencies before the system is actually implemented. Hence, the desired performance of the system may not be achieved, and it is necessary to change and tune the control laws (calibration phase) in order to compensate for the impact of these communication and execution delays. The fact that the calibration has to be performed on an actual plant can be very expensive and time-consuming, especially when the desired performance cannot be achieved using the current HWplatform and a redesign is requir。