Wheel force transducers (WFT) play an increasing role in endurance evaluation of road vehicles, ride and handling optimization, tire development and vehicle dynamics. Seven WFT-systems, which split basically into three design categories: strain gaged beam and spoke, individual load cells and mechanically separated load components are looked at in this investigation.
After a general evaluation the two systems which seem to be most promissing are compared in more detail: Angle error correction and material selection (Titanium alloy versus carbon fibre composite) appeared to be the most significant differences of these two systems.
FE-temperature analysis shows that during downhill braking temperature limits of the carbon fibre material are reached or exceeded. As in addition manufacturing of the special wheels (also partly made of carbon fibre) is expensive and cannot be done by the customer, using light weight metals seems to be the better choice.
Due to suspension kinematics the knuckle rotates relatively to the vehicle body. All WFT-systems connecting the angle encoder to this component show significant errors (called “angle error”) in the vertical direction force Fz, moment Mz (up to 10%) and in the longitudinal direction force Fx, moment Mx (up to and even more than 100%). Thus an “angle error”-correction system is crucial.