The Analysis, Improvement And Test Of Real-Time Performance For CAN Bus

The CAN Bus is now increasingly and extensively used in industry control,automobile electronics, mechanical manufacturing and other area where require high real-time ability. For some application of short frame, CAN bus is very flexible and has perfect ability of real-time performance. However, one of the perceived drawbacks of CAN is the inability to bound accurately the worst-case response time of a given message.This paper presents the reaserch background of CAN bus real-time ability firstly. And then explains CAN protocol precisely. According to the media access controlling method of CAN protocol, the reason of delay time was discussed. A kind of message delay mathematical model was set up and extended under nomal and error condition. To improve the real-time performance of CAN bus, the paper apply a higher protocol STT-CAN which employ the method of TDMA on traditional CAN bus.We also design a real-time testing system to evaluate the delay time in CAN mode and STT-CAN mode. Both hardware and software components were illustrated detailedly. At last the result of test was calculated and given out. The result indicate that the real-time ability of STT-CAN protocol performed better than CAN protocol under some conditions. But its flexibility is reduced a little.