A New Auxiliary Steering Angle Sensor for Power-Steering in Four-Wheelers

Electric Power-steering (EPS) has currently become one of the most essential features of a four-wheeler. An EPS module has a Steering Angle Sensor (SAS) that detects the angular displacement of the steering wheel made by the driver and produces signals that will in turn trigger the electric motor in the steering assembly to rotate the front wheels of the vehicle as required. When the SAS is faulty or aged, its functionality will be compromised and this can affect the passenger’s safety. Therefore, it is being proposed to install an auxiliary SAS on all four-wheelers. This auxiliary SAS will be also calibrated just like the built-in SAS of the vehicle. Therefore, any the difference between its indication and the actual front-wheel orientation will point to an issue in the EPS. Thus, it will act as a condition assessment tool for the EPS. But since this is an add-on system, its output can be also made to serve additional functions such as, data collection, parking assistance etc. The choice of transducer for this auxiliary SAS is a resistive potentiometric transducer as it can be easily coupled with the steering rod, making it a plug & play system. But, resistive transducers too are prone to wear & tear. Hence a new non-contact type transducer has been developed whose details are being presented in this paper. This paper also presents some preliminary evaluation results of this new sensor.