Design And Development Of EOL Test System For Commercial Vehicle Air ABS Controller

With the government's vigorous implementation of air ABS standards in the field of commercial vehicles,the demand for commercial vehicle air ABS products are increasing continuously.EOL(End of Line)test technology for air ABS controller lags behind the development of the controller itself since domestic market is in the process of nationalization.The EOL test technology has become an important factor which limits the output and quality of domestic controllers.Therefore,taking a series of domestic commercial vehicle air ABS controller as test object,a commercial vehicle air ABS controller EOL test system with high stability,high efficiency and high economy was designed and developed by adopting the integrate method of theory analysis and prototype test.The main research work is as follows.(1)On basis of test object characteristics and enterprise demands,functional requirements and performance indicators of EOL test system were determined.Based on unit-integration test principle,EOL test mechanism was investigated.Through constructing wheel speed simulation model,the relation among test condition,wheel speed and ABS valve control logic was obtained.EOL test system scheme and workflow were designed on basis of functional requirements and test mechanism.The analysis indicates that the key to raising test efficiency and reducing rated power consumption lies in the design of fixture pneumatic circuit and control unit.(2)Framework of automatic fixture and its pneumatic circuit was designed.In order to raise EOL test efficiency and reduce system rated power,influences of circuit diameter and pressure on fixture action time and circuit air consumption were analyzed by modeling the pneumatic circuit.Parameter optimization design for dual target was implemented by adopting response surface and min-max standardization method and the optimal circuit diameter and pressure were obtained.(3)The embedded control unit of the EOL test system design was described from three aspects,i.e.,hardware designing,programming and wheel speed simulating.Adopting modular design method,control unit hardware was designed including system basic module,A/D module,A/O module,etc.Corresponding basic drivers were developed according to hardware modules.Algorithm for application layer was developed to implement automatic execution of EOL test system workflow.Wheel speed simulation model was established and coded based on MATLAB/Simulink to port into the embedded program.(4)Prototype of commercial vehicle air ABS controller EOL test system was set up based on the development of automatic fixture and control unit.Prototype test plan was designed and carried out to verify the functions and performance indicators of the EOL test system.The commercial vehicle air ABS controller EOL test system is in accordance with the development trend of automotive electronic product EOL test technology.The work of this dissertation can provide theoretical and technical basis for the EOL test technology research of air ABS controller and related automotive electronic products.