SCHEDULING AND TIMING ANALYSIS FOR SAFETY-CRITICAL REAL-TIME SYSTEMS

摘要

The car you drive almost certainly depends for its safe operation on concurrent software executing within embedded systems. And as brake-by-wire, steer-by-wire and throttle-by-wire systems become more common-place, your safety will become ever more dependent on the timing properties of these systems.rnThe diagram in Figure 1 represents a brake-by-wire system. Its control unit (ECU1) reads the sensors, computes the outputs, writes the outputs to the actuators (e.g. ECU2) and resets the watchdog timer - set to 20ms. This system worked fine, but after a small change in the software the steering mechanism became wobbly. What had happened?