Influence of Load Prediction Equation Variations on Balance Load Predictions

A new approach is presented that may be used to assess the influence of load prediction equation variations on strain-gage balance load predictions. Small coefficient differences of a load prediction equation are often observed if a coefficient obtained during the analysis of a new balance calibration data set is compared with the corresponding coefficient that was obtained during the analysis of an older data set. The suggested approach uses the first derivative of the predicted load component with respect to the coefficient's regression model term as input. This first derivative equals the coefficient of the regression model term of the given calibration data if the Non-Iterative Method is applied. Therefore, the new approach can be used for the assessment of each individual regression model coefficient that the Non-Iterative Method uses. The approach can also be used for the assessment of the coefficients of the non-iterative part of the load iteration equation that the Iterative Method needs for the load prediction. Machine calibration and check load data of NASA's MC60D six-component force balance are used to illustrate application and benefits of the new approach.