Theoretical and experimental investigation of six-degree-of-freedom force/thrust measurement stand

Abstract

Thrust testing units with a piezoelectric dynamometer have unique traits such as excessive stiffness, tremendous measurement accuracy, dynamic performance and no hysteresis. These are widely used in the applications requiring force/ thrust measurements in the aerospace industry and high-end tool condition monitoring. The performance of these units is necessary to be evaluated. In this study, an improved layout of six-degree of freedom force/thrust measurement stand is proposed and analysed theoretically and experimentally. The measurement stand is a structural component to measure six components of force, such as axial force/thrust (FX, FY, and FZ) and other components (MX, MY, and MZ). Test stand consists of seven piezoelectric sensors in two sections. The front part consists of four piezoelectric force sensors, while the rear part consists of three sensors. The rear section is hexagonal, with three sensors mounted at 120°. The measurement stand can measure the principal force/thrust up to 50,000 N. A mathematical model is derived for every sensor against forces in all directions. To calibrate the stand, a calibration platform is designed and fabricated. The calibration platform can generate a range of forces/moments. Calibration experiments verifies that the measurement stand is fairly functional to measure variety of forces/moments with high repeatability.