| The Transmission Control Unit(TCU)of the Dual Clutch Transmission(DCT)is the central brain responsible for ensuring the proper function and performance of the DCT.The application of precise,real-time,efficient,and effective test cases is crucial for verifying the control strategy of the TCU,especially during hardware-in-the-loop testing.Developing well-designed test cases not only improves testing efficiency and ensures the correctness,effectiveness,and coverage of the tests,but also facilitates the maintenance and updates of the test cases in the future.Therefore,the development of high-quality test cases is of practical significance and engineering value for ensuring the proper and reliable function of the TCU.This paper focuses on the testing requirements analysis,test case design and review,and test verification of the control strategy of a certain DCT Transmission Control Unit(TCU).The following aspects of work have been carried out:(1)Analysis of the control strategy and testing requirements of the TCU.Based on the vehicle usage conditions,the control functions of the DCT TCU have been comprehensively analyzed.Taking low-speed control,gear position control,and shift control as examples,the control strategies of the TCU have been analyzed.The testing requirements and testing items for the low-speed crawling control,starting control,gear shifting control,and other functions have been identified,and the testing points have been further extracted using mind mapping.(2)Test case design and review.By using a combination of weak robust equivalent class partitioning and robust boundary value analysis,more than 2,000 functional test cases have been designed based on the testing points extracted from the testing requirements.The test cases have been designed for the brake crawling,D-gear starting,and gear shifting control functions of the TCU.The test case design has been reviewed in accordance with relevant enterprise protocols and regulations,and the results show that the designed test cases are characterized by clear,concise,accurate,reusable,and maintainable language,and comply with the principles of testing based on testing requirements,determinability,and reproducibility.The test cases have passed the design review.(3)Test verification and application of test cases.The hardware-in-the-loop(HIL)simulation testing method has been used to study the hardware and software of the testing platform,and the HIL testing platform has been built by integrating the software and hardware.The hardware selection includes the DSPACE SCALEXIO cabinet and various boards owned by the enterprise,and they have been appropriately matched.Based on the signal pin definition of the controller,the mapping relationship between the TCU signal pins and the I/O board channels has been established.The closed-loop model has been built in the test system software,and the integration of the software and hardware has been completed in the HIL testing platform.To ensure the correctness and reliability of the testing platform and test cases,the test cases have been tested and reviewed.The brake crawling,D-gear starting,and gear shifting functions have been tested and reviewed using the HIL testing platform.The test results show that the TCU control modules function normally,and all the test cases of the testing points have passed the HIL test.The control software that has passed the HIL test has been packaged for flash writing and has undergone vehicle-level testing,including D-gear crawling on flat/steep roads,D-gear starting on flat/steep roads,and D-gear shifting at a constant throttle.The vehicle-level test results show that they comply with the standards and have passed the test,further verifying the correctness and reliability of the control software,as well as the correctness,effectiveness,and coverage of the tested test cases. |
PDF Full Text Request