Low-Cost Slip Angle Sensor for Use in Analysing Vehicle Handling Characteristics

Tyres are essential to a vehicle; all of the forces are transmitted through them and they have to try and resist these forces while maintaining grip to the road. Maximising the performance of tyres is a major factor in vehicle dynamics and has far reaching implications for vehicle handling and safety. Tyre slip angle is one of the central pieces of data used to analyse tyres. Slip angle is the difference between where a wheel is pointing and the actual direction of travel. It is developed due to the elastic nature of rubber tyres trying to resist the turning moment. In this project a low-cost, $1-2k, slip angle sensor is developed. The underlying theory and mechanical/electrical design are presented. The design is focused on a mechanical device to measure the vehicle sideslip angle, which can then be transformed into the front and rear slip angle. The device in question is a manual trailing arm in direct contact to the road and physically attached to the vehicles longitudinal axis. The theory centres around the trailing arm following the tangent of the curve while the fixed section remains in-line with the vehicle, creating an angular difference that is measured by a potentiometer. The dissertation encompasses the background research, conceptual design, solid modelling and finite element analysis through to prototype manufacture and testing. The concept was designed and modelled using Creo Parametric 3.0 solid modelling software and analysed using its internal finite element software. The prototype was then manufactured using a combination of off-the-shelf components and fully manufactured parts. The prototype was tested with the help of the Curtin Motorsport Team using their Formula SAE competition vehicle. During the testing the design itself performed well and the theory appeared viable. However, electrical issues and interference during the test rendered the test data unsuitable for proving the theory, or comparison with other technologies. The results suggest that the approach and theory will work. The design itself is workable and shows good signs of being a viable low-cost option for measuring slip angle. Further testing and development is warranted