Research On Algorithm Of Non-contact Steering Wheel Angle Detection

With the wide application of intelligent control system like electronic power steering system and electronic stability system in cars, how to design a steering wheel angle sensor with large-scale and high precision has been a research hotspot of automotive electronics manufacturers and related institutes. In order to meet the requirement of the above-mentioned intelligent control system, this dissertation proposes mean filtering algorithm and piecewise functioning method, which improves the output precision and the measure range of the steering wheel angle sensor.Firstly, according to the requirement of the output angle’s precision of steering wheel angle sensor, a test platform and measure system of angle is established. This platform uses the angle of high precision grating encoding as the reference value, and a scheme of circumvolution is adopted to measure the angle. Based on a three gear mechanism, the measure system of steering wheel through an analysis of magnetic field intensity and a design of circuit diagram is established.Secondly, making full use of the high precision of small gear and high reliability of vernier principle algorithm, the mean filtering algorithm is put forward. This algorithm avoids the difference error in the vernier principle algorithm and reflects the accuracy of output angle of steering wheel angle sensor more precisely. The segmentation function algorithm bases on the vernier principle algorithm and the characteristic of angle sensor, and this algorithm realizes the extension of measure range of steering wheel angle sensor without adjusting the tooth number relationship among the three gears. The segmentation function algorithm solves the problem that precision of detection declines linearly with the increasement of measure range.Finally, the static performances of the output angle signal of vernier principle algorithm and the algorithm proposed are analyzed respectively, and the result reveals that a great superiority when using the algorithm proposed.