Real Time Message Scheduling and Bandwidth Allocation on CAN Bus

• Main Authors: H.W.Yan, 顏豪緯
• Other Authors: C.P.Hung"M.S.Chen
• Format: Others
• Language: zh-TW
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/64694852930555508796

碩士 === 大葉大學 === 電機工程學系碩士班 === 93 === CAN (Controller Area Network) was developed in 1980’s, it was originally designed for automobile industry but now it is also widely applied on industrial automation. CAN overcomes the problems that traditionally centralized control encountered, but it also brings other problems. The most serious problem is the requirement of Real-Time System. Some scholars present methods to schedule messages transmission and attempt to satisfy the requirement of Real-Time System, including FP (Fixed priority), CMS (Centralized Master-Slaves) and EDF (Earliest Deadline First). But there are still some drawbacks in these methods, we will integrate the advantages and disadvantages of these methods and present another method named “MCFC (Multiple Classes FIFO CAN)”. In this paper, we use MCFC to schedule messages transmission on CAN bus and ensure it can satisfy the requirement of Real-Time System. MCFC can be divided into two parts. First, we use MSC (Messages Schedule Controller) to schedule the different class messages transmission. Second, we use FIFO (First In First Out) to schedule the same class messages transmission. MSC is the structure of RBFN (Radial Basis Function Network), it can allocate bandwidth to different class messages according to messages waiting time and network flow. We will present the methods of BTT (Back Through Time), PI (Parameter Identification) and SI (Structure Identification) to make MSC having the capability of self learning and adjusting. From the result of simulation, MCFC (MSC+FIFO) can reduce the rate of delay transmission effectively.