Instrumentations Design Of Automobile Security Performance

At present, the demand for motor vehicle detection is growing fast. But the vehicle automatic detection line is built mainly in large and medium cities with high construction and test costs. Therefore, according to current market needs, researching and developing a set of stand-alone instruments, which is easy to combine, with high universality, small bulk, simple structure, high reliability and low-cost which can meet the needs of different users, would bring huge social and economic benefits.This paper discussed three aspects of the common vehicle detections, including the braking performance test, the steering wheel sideslip test and the speed approval, and compared their common detection methods. Three stand-alone instrumentations were designed according to the characteristics of the roller opposite forces type brake tester, the double slide-type sideslip test-bed and the roller automobile speedometer tester. A 16-bit microcontroller selected from Microchip Inc.'s dsPIC30F series as core control chip, together with front-end circuit, consisted of the hardware of the instrumentations. The running process control of the tester, especially the axle brake composite tester and its panel display, were accomplished by the software. Detection process can be automated. Piecewise linear calibration was used for steering wheel sideslip test and vehicle braking test in order to reduce the sensor's measurement error caused by nonlinearity. Necessary system parameters were pre-stored, which can be modified based on the actual situation to make instrumentations more universal.Field calibration tests were carried out and the running process of tester were checked. The instrumentations have the characteristics of convenient debugging, stable operation and high accuracy, and their performances are better than the existing ones. They meet the design requirements.