Dynamic Test Scheduling in Hardware In the Loop Simulation of Commercial Vehicles 2012-01-2028
Modern day commercial vehicles use Electronic Control Units that are complex. Integration testing of these Control Units as one control system has many challenges. Many of these challenges are met by driving Integration test activities towards automation, based on Hardware In the Loop (HIL) simulation. The simulation scenarios consist of functional tests designed with the aim of replicating real world tests that are performed in an actual vehicle. However, most of the HIL simulators used these days in industry have functional tests which are assumed to be independent and are executed in a sequence pre-determined by a Test engineer. We demonstrate that the assumption of test independence doesn't hold well in many simulation scenarios. Integration test process efficiency can be shown to be improved by dynamically scheduling functional tests while simulation is running instead of a pre-determined sequence. We propose two solutions to for the dynamic test scheduling problem. One solution is to model the integration test process as a state machine. The second proposed solution is functionally similar to a state machine but its implementation is derived from logic design. The dynamic test scheduler was implemented in a software module and integrated to the HIL simulator. It acts like a Test engineer, virtually driving the vehicle in simulation and dynamically scheduling the tests based on states of the vehicle dynamic control system.