Vehicle Braking Performance Testing Measurement Research And The Portable Testing Instrument Design

This paper mainly discussed the Vehicle Braking Performance Testing Method and designed the Portable Testing Instrument based on LabVIEW and MATLAB mixed programming. The measurement vectors are vehicle acceleration and wheel velocity which acquired from the vehicle Anti-lock Braking System's ECU. Other parameters are estimated by soft measurement algorithm. The data acquisition system is based on USB bus. The whole software platform is based on the Virtual Device (LabVIEW) System. There are three parts of testing content: The whole vehicle braking performance test, the ABS work performance test and the vehicle braking stability performance test. The Virtual Testing Instrument not only provided the new idea for vehicle performance road test and also offered the test platform for correlated parameters design.The research content of this paper includes five parts:Firstly, the schematic design of the vehicle performance portable testinginstrument. We realized the braking performance road testing only usingacceleration sensor.Secondly, the design of USB data acquisition system. As the mainly hardwaredevice of the testing instrument, the USB data acquisition device not only cansuccessfully collect the data, but also has simple interface that fit for portableinstrument utilizing.Thirdly, the vehicle braking state estimation based on Extended Kalman Filter.We estimate the vehicle braking state and tire friction forces based onseven-degree of freedom vehicle dynamic model and adaptive Kalman filter.We took the wheel velocity and the vehicle acceleration as measurementvector. This method also avoided to create the tire model that simplified thecalculate process and realized the on-line estimation for the statisticalcharacteristic of system noise and observation noise.