Event-triggered controller design of nonlinear discrete-time networked control systems in T-S fuzzy model

This article is concerned with event-triggered fuzzy control design for a class of discrete-time nonlinear networked control systems (NCSs) with time-varying communication delays. Firstly, a more general mixed event-triggering scheme (ETS) is proposed. Secondly, considering the effects of the ETS and communication delays, based on the T-S fuzzy model scheme and time delay system approach, the original nonlinear NCSs is reformulated as a new event-triggered networked T-S fuzzy systems with interval time-varying delays. Sufficient conditions for uniform ultimately bound (UUB) stability are established in terms of linear matrix inequalities (LMIs). In particular, the quantitative relation between the boundness of the stability region and the triggering parameters are studied in detail. Thirdly, a relative ETS is also provided, which can be seen as a special case of the above proposed mixed ETS. As a difference from the preceding results, sufficient conditions on the existence of desired fuzzy controller are derived to ensure the asymptotic stability of the closed-loop system with reduced communication frequency between sensors and controllers. Moreover, a co-design algorithm for simultaneously determining the gain matrices of the fuzzy controller and the triggering parameters is developed. Finally, two illustrative examples are presented to demonstrate the advantage of the proposed ETS and the effectiveness of the controller design method.     

COVALENT,a method for co-designing value exchange in community-centred design

Abstract

It is challenging to design for mutually beneficial relationships in a multi-actor service system when these actors have diverse and conflicting interests, and lack usable methods and tools that support the design process. This study introduces a novel method for co-designing value exchange (COVALENT). COVALENT integrates the value analysis model, co-design strategy and service design tools, to support the conceptualisation of reciprocal value exchanges based on the analysis of and matching between, stakeholders’ needs and resources. Its perceived effectiveness was validated through application to the development of community business models in Ulsan, South Korea. This study contributes to the knowledge of co-design by providing a method for co-designing services that aim to achieve reciprocal value exchanges in the context of community-centred design and by discussing the effectiveness of that method as perceived by users.     

State-of-the-art technologies and methodologies for collaborative product development systems

In order to facilitate product realisation processes, presently, research is actively being carried out to develop methodologies and technologies to support geographically dispersed teams to organise collaborative design based on the quickly evolving information technologies. A number of research works and commercial systems have appeared to provide solutions for collaborative and distributed product development, and the practical applications are getting more pervasive and mature. In this paper, the recently related works are summarised from three aspects—visualisation-based collaborative systems, co-design collaborative systems and CE (concurrent engineering)-based collaborative systems. Around these aspects, about 100 papers and 30 commercial systems/international standards published or launched recently are discussed. The current research and development statuses and issues, underlying algorithms, mechanisms and system architectures, and the future trends and challenges are explained and compared in detail.     

An interactive co-evolutionary CAD system for garment pattern design

Traditional CAD (Computer-Aided Design) methods in garment pattern design (GPD) fail to utilize the knowledge of experts for inexperienced designers. Moreover, the interactive and co-evolutionary features are not supported. We propose an interactive co-evolutionary CAD system for GPD (ICE-GCAD). The functionality model, modular architecture and data flow of the system are proposed. Then, the interactive co-evolutionary system whose core module is an immune-inspired co-evolutionary algorithm is studied. Finally, the flow of co-design in the system is proposed. As a case demonstration, we study a design sample of a leisure shirt. The experimental studies show that our approach has promising performance and appealing effects. We believe ICE-GCAD is applicable to support the collaboration among garment designers and experts.     

Algorithmic aspects for functional partitioning and scheduling in hardware/software co-design

Hardware/software (HW/SW) partitioning and scheduling are the crucial steps during HW/SW co-design. It has been shown that they are classical combinatorial optimization problems. Due to the possible sequential or concurrent execution of the tasks, HW/SW partitioning and scheduling has become more difficult to solve optimally. In this paper more efficient heuristic algorithms are proposed for the HW/SW partitioning and scheduling. The proposed algorithm partitions a task graph by iteratively moving the task with highest benefit-to-area ratio in higher priority. The benefit-to-area ratio is updated in each iteration step to cater for the task concurrence. The proposed algorithm for task scheduling executes the task lying in hardware-only critical path in higher priority to enhance the task forecast. A large body of experimental results conclusively shows that the proposed heuristic algorithm for partitioning is superior to the latest efficient combinatorial algorithm (Tabu search) cited in this paper. Moreover, the Tabu search for partitioning has been further improved by utilizing the proposed heuristic solution as its initial solution. In addition, the proposed scheduling algorithm obtains the improvements over the most widely used approaches by up to 10% without large increase in running time. This work was presented in part at 2006 IEEE International Conference on Field Programmable Technology (ICFPT).     

Particle swarm optimization applied to the co-design of a fuel cell air circuit

This paper presents an optimization approach applied to a whole fuel cell (FC) air supply system including its geometry and its control. The aim is to optimize its power consumption along with its mass. Particle swarm optimization (PSO) algorithm is used to define the design parameters of both permanent magnet synchronous motor (PMSM) and a fuzzy logic controller (FLC). The results are compared with those obtained by a sequential optimization process and advantages of co-design optimization approach are clearly shown. Indeed, a significant reduction of the objective function (made up on both motor mass and energy consumption) on a considered operating cycle can be obtained.     

SystemC:一种新的系统建模语言

文章介绍了一种国外正在研究的新的系统建模语言SystemC，因其较好地结合了面向对象的设计方法和硬件建模的特点，从而有望解决系统建模和HW／SW协同设计中等一系列问题。     

QoS-oriented design of embedded systems with specification PEARL

Only recently have methodical tools adequate to design real-time systems been formally introduced in design methodologies. Naturally, they were present from the beginning, but due to the large diversity of embedded systems’ areas of deployment, specially dedicated formalisms have been developed and used. High-level language programming and integration of modeling formalisms into design methods eased the development of more complex real-time applications. With the emerging object-oriented programming languages and design methods, their integration into larger information systems has become more transparent. It was the UML methodology, however, which eventually merged also the design methods and concepts of real-time systems into a consistent whole. It took a large consortium and a long process to persuade industry of the benefits the new integral methodology can offer. On the other hand, there are some trade-offs, and there are some features not completely covered, yet. Here, a different, more straightforward approach to program and design (embedded) real-time systems is presented. Since it emerged from the real-time community, it includes most features relevant there. Independent of the UML profile for schedulability, performance and time specification, a profile was devised for use in PEARL-oriented UML design. The strengths of the mentioned language and design methods for QoS-oriented design of (embedded) real-time systems are emphasised throughout this article.     

嵌入式系统软硬件功能分配的研究

首先简要介绍了嵌入式系统及其传统的顺序设计方法和协同设计方法，然后论述了软硬件划分问题的由来、软硬件划分在协同设计中的地位、发展过程、主要问题及技术难点。     

面向RTOS的嵌入式软件模拟器构造与实现方法

提出一种快速嵌入式软件验证工具——RTOS软件模拟器。在RTOS软件模拟器验证方法中，利用RTOS模块化、层次化设计特点，快速实现嵌入式软件在不同目标机器间的代码移植，通过扩展RTOS API功能，建立硬件模拟驱动，实现软件模拟器和硬件模拟器通信连接和协同模拟同步控制。RTOS软件模拟器克服ISS速度低的缺点，从更高层次验证嵌入式软件功能。