Refined Design of a Measuring Wheel

The measurement of the contact forces between road and tires is of fundamental importance while designing road vehicle control systems. In this paper, the detail design of a measuring wheel (smart wheel) for a small two-seater vehicle is presented. The smart wheel concept design is based on a patented three-spoke structure connected to the wheel rim. The spokes are instrumented by means of strain gauges and the smart wheel is able to measure the three forces and the three moments acting at the interface between the tire and the road. The main objective of the design process presented in the paper is improving the sensibility and the accuracy of the measuring system while limiting its mass complying with maximum stress constraints. An iterative process is undertaken by employing both simple (analytical) and complex (finite element) models of the smart wheel to evaluate its performance and the structural stress levels during vehicle running. The complex model includes a finite element model of the tire to accurately apply the loads on the rim while operating. The simple design, the good performance, in terms of accuracy, dynamic behaviour, limited mass and the low cost represent the main features of the designed system.