INTELLIGENT TEST-CASE GENERATION FOR AUTOMATED VALIDATION OF TCUs

Automatic transmissions are difficult to test and validate, due to the complex interaction of mechanics, hydraulics, electronics, and transmission control software. This paper introduces how simulation-based automatic generation of test scenarios can maximize test coverage and reduce test workload at the same time. This tool, TestWeaver, has been applied by SAGW during the development of the application software for a new Dual-Clutch Transmission. TestWeaver is based on a novel approach that aims at maximizing test coverage with minimal work load for the test engineer specifying test cases. TestWeaver can be applied to Simulink models (MiL), SiL setups or HiL setups. For testing a system, TestWeaver does not require any test scripts. Instead, TestWeaver generates, runs and evaluates thousands of tests cases (driving maneuvers) automatically using a unique technology for intelligent test generation and evaluation of reactive systems. The intelligent generation strategy guarantees high test coverage with reduced work effort for engineers. For their DCT application, SAGW used TestWeaver with Simulink models to identify issues such as gearshift oscillations, overtime shifts or clutch overheat. 10,000's of scenarios are generated overnight and provides fast feedback about maturity of a software release, typically within 12 hours. Specific uses cases and applications at SAGW are introduced. Besides MiL application, TestWeaver can also be connected to HiL systems in various manners. However, the main drawbacks of HiL testing are (1) much slower speed compared to MiL/SiL and (2) increased complexity due to simulation non-determinisms, management of fault codes and EEPROM reset. At SAGW, TestWeaver scenario generation is done on MiL to quickly reach a high coverage. Selected scenarios are then reproduced and verified on HiL.