基于等幅变频晋升CAN总线动态调度算法的研究

Constant Amplitude and Variable Frequency Based Dynamic Scheduling Algorithm for CAN Bus

针对目前CAN总线帧标识域编码欠佳、动态调度算法实现复杂和优先权更新开销较大等问题,为提高网络利用率、保证报文传输实时性和改善网络使用公平性,根据优先级动态晋升原理,提出一种CAN报文帧标识域分段编码、以幅度相等频率不同方式晋升(SSVP)的动态调度算法.首先,阐明动态调度算法的基本要求、晋升函数和晋升控制要素——幅度与频率.然后定义了帧标识域的分段编码和基于截止期的晋升函数,讨论类内优先权的初始化、更新幅度和更新频率,描述SSVP动态调度算法,并对算法的可调度性和通信时延进行分析.最后,仿真实验结果表明SSVP动态调度算法能可靠地实现报文通信和提高网络利用率.

Currently, the controller area network （CAN） bus suffers from poor frame-identifier coding, a complex dynamic scheduling algorithm, and a large overhead of priority updating. To improve network utilization, en- sure real-time data transmission, and improve the fairness of network use, we propose a dynamic scheduling algorithm in which the CAN message frame identifier domain is segmented, encoding the amplitude and varia- ble frequency promotion （SSVP） according to the principle of priority dynamic promotion. First, we demon- strate the basic requirements for the dynamic scheduling algorithm, the promotion function, and its control el- ements （i. e., amplitude and frequency）. We then define the segmented encoding for a frame identifier and promotion-function-based deadline; and discuss the initialization, updating amplitude, and the updating fre- quency of intra-class priority. We describe the SSVP dynamic scheduling algorithm and analyze its scheduling ability and communication time delay. The simulation results show that the SSVP dynamic scheduling algo- rithm is reliable for message communication and can improve network utilization,