In contrast to the previous test rigs, only the sensor element is calibrated without the rim and tire. The LBF scientists screw the wheels over the wheel flange onto a lockable turntable. Instead of the rim, they attach a load introduction ring via which they introduce the loads in the directions to be tested. This is done at eight positions of the wheel circumference - not in combination, but one after the other. The loads are increased stepwise or continuously and recorded via a single force measuring element located in the direct load flow. A load calculation is not necessary. This increases accuracy and eliminates sources of error.
The new calibration test bench can be used to determine the sensitivity of the wheel force sensor in the radial, lateral and tangential load directions and to determine the measuring accuracy for each force component. The crosstalk between the determined load components is calculated. "Sensors should be calibrated at least every two years. This ensures measurement accuracy and identifies possible problems with the sensors," emphasizes Käsgen.
More information: https://www.lbf.fraunhofer.de/en.html