Abstract: To meet the need to improve the control precision of rocket engines, a piezoelectric measurement system is developed with quartz crystal as the forcesensitive element for measuring the dynamic thrust vector of an attitude/orbit rocket. After introducing and calculating the describing parameters of the thrust vector, this article puts forward a measurement scheme. According to the static balance principle, the general equations for solving the describing parameters are derived and proved reliable. The nonlinear modal analysis is improved to build a theoretical dynamic model based on actual frequency response and phase response. The dynamic performance and the pulse measurement performance are obtained by Laplace transform and the inverse and convolution theorem. In studying the pulse measurement, dynamic error is produced, mainly by acceleration. A compensation algorithm for acceleration is advanced based on the theoretical dynamic model. Finally, the experimental results prove that the measurement scheme and the compensation algorithm are feasible and reasonable.

Key words: thrust measurement, modal analysis, dynamic response, acceleration