基于改进型遗传算法优化的TTCAN网络研究与实现

发布时间：2018-06-03 01:26

本文选题：遗传算法 + CAN总线　；参考：《杭州电子科技大学》2017年硕士论文

【摘要】：CAN总线相比于传统现场总线在可靠性、实时性和灵活性方面具有很大的优势,被广泛应用于汽车工业、航空航天、船舶、工业控制、传感器等领域。在CAN协议使用过程中发现其事件触发机制的缺陷,会导致CAN总线在一些对于实时性、稳定性要求特别高的系统中不能很好的工作。为了解决CAN协议缺陷,基于时间触发的TTCAN协议被提出,并越来越受到人们的重视。TTCAN采用分割时间窗的方法保证了周期型消息的实时性,同时设立仲裁窗兼顾事件型消息的传输。同样,TTCAN协议存在着系统矩阵优化问题规模过大,不能应用于动态网络等问题。本文立足于TTCAN协议和遗传算法,对TTCAN系统矩阵和系统部署更新方式进行了改进,完成了算法设计和实验验证。具体内容如下:1.提出了使用改进型遗传算法优化TTCAN系统矩阵。该算法能够有效提高TTCAN的实时性、可靠性和带宽利用率。针对提出的矩阵编码和实数编码相结合的创新性编码方式,设计出生成系统矩阵算法,解决了随机生成初始个体不合理的问题,同时相应的改变了交叉、突变步骤;2.提出了一种动态更新TTCAN系统矩阵机制。解决了传统TTCAN系统矩阵采用静态离线预先生成而导致其无法应用于动态网络的缺陷。该机制在网络发生改变时,能够自动重新生成新的系统矩阵并部署到系统中;3.设计并实现实验验证平台。使用该平台对改进型遗传算法优化TTCAN系统矩阵算法和动态更新机制进行验证。该平台是包含多个节点的TTCAN网络,由嵌入式开发平台(上位机)和采用STM32F105作为MCU的节点共同组成。针对该实验平台设计了基于嵌入式Linux与STM32环境的CAN驱动和QT总控程序;4.基于TTCAN网络系统实验验证平台,开展了改进型遗传算法的性能分析,实际测试了动态更新TTCAN系统矩阵的性能。并且对硬件系统进行了基本功能、实时性和错误率的测试。实验表明,以汽车工业中的国际标准PSA消息集合为例,本文算法可以将TTCAN网络的带宽利用率提高4.3%,在仲裁窗范围内每秒钟增加了73个随机报文的发送机会,提高了网络的可靠性。动态更新机制能够在网络节点发生增删时保证带宽利用率始终维持在高水平,可以满足应用于动态网络的需求。
[Abstract]:Compared with traditional fieldbus, CAN bus has great advantages in reliability, real-time and flexibility, and is widely used in automotive industry, aerospace, ship, industrial control, sensor and other fields. In the process of using CAN protocol, the defects of event triggering mechanism will be found, which will lead to the CAN bus not working well in some systems with high real-time and high stability requirements. In order to solve the defect of CAN protocol, the time-triggered TTCAN protocol is proposed, and more people pay attention to it. The method of partitioning time window ensures the real-time performance of periodic message. At the same time, an arbitration window is set up to take into account the transmission of event-type message. The TTCAN protocol also has some problems such as the system matrix optimization problem is too large and can not be applied to the dynamic network and so on. Based on the TTCAN protocol and genetic algorithm, this paper improves the TTCAN system matrix and system deployment update method, and completes the algorithm design and experimental verification. The details are as follows: 1. An improved genetic algorithm is proposed to optimize the TTCAN system matrix. This algorithm can effectively improve the real-time, reliability and bandwidth utilization of TTCAN. Aiming at the innovative coding method of combining matrix coding with real number coding, an algorithm of generating system matrix is designed, which solves the unreasonable problem of random generation of initial individuals, and changes the crossover and mutation steps accordingly. A dynamic updating TTCAN system matrix mechanism is proposed. It solves the problem that the traditional TTCAN system matrix can not be applied to the dynamic network because of its static off-line pre-generation. When the network changes, the mechanism can automatically regenerate the new system matrix and deploy it to the system. The experimental verification platform is designed and implemented. The platform is used to verify the matrix algorithm and dynamic updating mechanism of the improved genetic algorithm for optimizing TTCAN system. The platform is a multi-node TTCAN network, which is composed of embedded development platform (host computer) and STM32F105 as the node of MCU. The CAN driver and QT master control program based on embedded Linux and STM32 environment are designed for this experiment platform. Based on the experimental verification platform of TTCAN network system, the performance analysis of improved genetic algorithm is carried out, and the performance of dynamically updating TTCAN system matrix is tested. The basic function, real-time and error rate of the hardware system are tested. The experimental results show that, taking the international standard PSA message set in the automotive industry as an example, the bandwidth utilization of TTCAN network can be increased by 4.3%, and 73 random packets per second are added in the arbitration window. The reliability of the network is improved. The dynamic updating mechanism can ensure that the bandwidth utilization rate remains at a high level when the network node is added or deleted, and can meet the requirements of the dynamic network.
【学位授予单位】：杭州电子科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP18;TP273

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