Time-Triggered Cooperative Scheduling Distributed Embedded System And Its Application In Vehicle ACCS

Distribute Embedded Systems (DES) which are based on CAN-bus are implemented everywhere, the function of control and protection of the system is become more and more complicated. During the manufacturing these highly safety required system, it is need to implement full test and parameter confirming of the digital controller. It is not appropriate to test on the real system,before debug the all malfunctioning elements and errors in the controller.Using the real-time Simulation is an efficient way to solve the problem, replace the real"actuator-vehicle-sensor"with its real-time model, connect with the real embedded controller to form a close-loop control system. For there are real control computer hardware I/O in the loop, it is called Hardware in the loop Simulation, HIL for short. This paper follows the recent research result from home and abroad, complete a series of Hardware-In- the-Loop (HIL) simulation that base on the ARM7 LPC2119 CPU.This paper deeply analyses the preemptive scheduler and the cooperative scheduler, based on the time-triggered cooperative scheduler which propounded by Pont, migrated this embedded scheduler on one node ARM MPU. Time-triggered cooperative scheduler uses timer to drive task scheduling and to synchronize the slave nodes. No task pre-emption occurs in the whole system, and it has milliseconds response time, has the characteristics of reliability and divination.Communication and synchronization are crucial technology of distributed control system, they carry out the resource sharing. This paper analyses the standard CAN bus protocol in detail, complete a type of laboratorial time-triggered CAN protocol and a time-triggered distributed cooperative scheduler for multi-processor. The HIL simulation is used to test the real time performance and reliability of the protocol and scheduler.