Combinatorial Testing for an Automotive Hybrid Electric Vehicle Control System: A Case Study

Embedded electrical systems for passenger vehicles are highly complex distributed systems with varying system boundaries. The surge towards further electrification of vehicles demands the deployment of high voltage systems that provide propulsion through an electric motor as part of a hybrid electric or pure electric drive train. This demands additional care and robust deployment to ensure the safety of the end user and the environment around them. Exhaustive testing is not feasible for large systems and the use of formal approaches can be restrictive. In the presented work a combinatorial test approach is applied to a real Hybrid Electric Vehicle control system as part of a hardware-in-the-loop test system. 2-way, 3-way and mixed strength up to 4-way testing is carried out. The concept of CAN main and local is devised to intercept CAN messages and replace them with the generated combinatorial tests using the HIL simulator's own processor to assure real-time testing. Early results indicate that the approach is effective in exposing incidents in system behavior not normally found during traditional functional testing.