An improved sensor system for wheel force detection with motion-force decoupling technique

Wheel force transducer/sensor (WFT) is an effective instrument in automotive testing field to directly measure the wheel forces and moments under dynamic conditions. As a large-range load sensor mounted on the wheel, there are added inertial effect and rotational couplings that will greatly decrease the sensor accuracy, but they can hardly be eliminated by the conventional calibration with the standard loading devices. In this paper, the motion-force decoupling technique is proposed to address this problem. An improved wheel force sensor system is developed by integrating the force-sensing unit, the angle encoder, and an inertial measurement unit. The motion signals including the angle, angular rates and accelerations are used to compute the actual loads and compensate the errors of force measurement in rotating state of the wheel. Experiments are performed to verify the proposed approaches and calibrate the system. Road test also indicates that the sensor can be successfully used in practice to get more reasonable wheel loads.