Design and prototyping of a steering wheel angle measuring system for automotive quality tests

Vehicles just released from the assembly line have to undergo a series of quality tests, among which a calibration check of the steering wheel is performed. The already existent devices aimed to realize this check have large tolerances, making it difficult to achieve precise measurements. This thesis work is finalized to the design and development of a steering wheel angle measuring system granting high accuracy, versatility, simple mounting and low cost. The activity is realized in collaboration with the Turin-based engineering company AMET Srl involved in the development and design of automotive systems. On the basis of the previous studies realized on the project and the new research conducted on the subject was agreed to use inertial platforms to manage the measurement. An Extended Kalman Filter is designed to combine the data obtained from the accelerometers and gyroscopes employed, filtering the noise affecting them and providing the estimation of the steering wheel angle value. Three main components can be identified in the design of the measuring system: a device located on the steering wheel to carry out the angular measurements, a second measuring element placed on the steering column to sense the dynamic of the vehicle and a dedicated tool for the interface with the CAN network. The data collected from the CAN line concerns the speed of the vehicle and its identification number (VIN). The model of the system is realized and validated through a simulation campaign performed with the combination of MATLAB Simulink and CarSim environments. A conclusive experimental session, for which a first prototype of the device is realized, is carried out to test the model with real data. The validation phase confirmed the reliability of the model and the potential of the approach chosen, while the experimental activity stated the importance of highly accurate data to achieve the quality of the measurement required from specifications. In light of the results obtained, further work will focus on device engineering, in terms of construction and performance boost.