Abstract
No one can know how players exert forces and moments on the grip handle from the swing motion. Because the club is manipulated by the hands during swing motion, the upper limbs and the club make a closed multiple-segment loop. This paper proposed a calibration method of the instrumented club under several axial-load conditions for the purpose of studying various tensile-force conditions. The relationship between the sensor output voltage and the applied bending moment at each sensor showed very good linearity and showed little crosstalk in terms of the moments acting about other axes. However, as the tensile loads affected the relationship, the gradients of linearity were calculated by using interpolating functions with respect to the tensile loads. As for the axial forces, the sensor output voltages also showed good linearity with respect to the applied loads, but cross-talking occurred between the tensile forces and the applied bending moments measured at the sensor points. Therefore, the interferences terms were approximated by using polynomial functions and substituted by them. A skilled golf player volunteered to participate in this study as subject. He performed shots using sand wedge club. From the results obtained by this study, the validity of the proposed method was clarified.
