Measurement mothod based on stereo vision for nozzle motion

Stereo vision in motion measurement simultaneously acquires the sequence image of feature points from different view angle, and the related motion parameters of the moving targets are sovled on basis of the established equations and the 3D coordinates of the feature points in different moment. In recent years, it has emerged as an effective approach for contactless measurements. The nozzle motion parameters such as vector angle and rotation center are required to measure as very important index of rocket engine in ground testing. In this paper, a novel measurement method for nozzle motion parameters based on stereo vision is proposed. Firstly through nozzle's twice swing on different axes the nozzle motion coordinates system is established. Then every instantaneous vector angle and roation center can be obtained by solving pose matrix. Finally, the experiments test is present based on the nozzle motion platform, using the proposed method and validating the feasibility of the measurement method. The experiment results proved the method was able to measure nozzle motion parameters, and the measurement errors was relatively smaller as vector angle becoming smaller.