System Design of Automated Test Equipment for Electrical Control Units in Trucks

Abstract: The high level of complexity in today’s electronic systems increases the demands on an advanced validation and verification process. Automated testing facilitates and improves regression testing (rerun of previously executed test cases to uncover and track new bugs) with increased coverage and reduced costs as a result.  A vehicle contains multiple control units, each responsible for a specific part: the engine, brakes, gearbox etc. These intelligent systems must be tested thoroughly to ensure correct behavior - both under normal circumstances and when the vehicle is exposed to unexpected events such as electrical failure (short circuit, broken cables etc.). A breakout box, BOB, is a piece of testing equipment that can be used to induce electrical faults on the wiring of the control units. It is typically operated manually. The objective of this project is to develop an automated version, an ABOB.  A prototype that could induce various faults on arbitrary cables of a control unit was developed. The faults were: short circuit to a variable voltage source with connected or disconnected load, replacement of real signals with simulated ones and open load. The breakout box also performed internal measurements and supplied the user with feedback information about whether or not the test case was successfully executed. Several generations of the system were developed, where the final product had hardware support for up to six connected ECU ports and the possibility to distribute control signals to 256 different ECU ports via a computer based application and a set of communicating microprocessors.  This thesis project focuses on the software design of the ABOB. For further explanation of the hardware, the reader is advised to consult the report Hardware Synthesis of Automated Electrical Fault Testing in Trucks by Martin Orre.