Research On Vision Measurement Of Mass Center For Non-cooperative Target In Space

Vision Measurement for Non-cooperative Target in Space is widely used in space counterwork, fragment disposal, satellite on-orbit service, etc. It has many advantages, such as passiveness, real time, non-contact, high precision, etc. The research on Vision measurement of mass center is of significance for evaluating the movement of non-cooperative target in space. This paper combines rigid kinematics, proposes a novel method that applies vision measurement to position the mass center of non-cooperative target, and puts up a simulation for it. The method does nothing to the target, only applies vision measurement to affirm the feature points'velocity and position on the target when it is rotating, and calculates the mass center of the target afterwards. It has a wide application perspective.In the very beginning, a vision measurement system is designed according to practical application request; a classical precision evaluation method for binocular vision measurement system is introduced. Based on the classical precision evaluation method, the precision evaluation and validation is executed using the vision measurement system designed in this paper.A novel method that applies the feature points'velocity and position to position the mass center of non-cooperative target is proposed, namely mass center measurement based on rigid kinematics, and a superficial simulation demonstrates its validity. Ascertaining the measurement conditions, this paper has also discussed the parameters that can be measured in other conditions.A method that applies quaternion dynamic equations and Euler dynamic equations to calculate the symmetrical satellite freeness movement parameter relative to inertia reference frame is adopted and the movement parameter is simulated by Runge-Kutta method. By the simulation of simplified symmetrical satellite model's movement parameters, the correctness of the simulation is approved. Using the symmetrical satellite movement parameters, the conclusion is validated that the mass center can be calculated by just a period of observation when the rotation is not around the inertia principal axis. In the end, the influence of whirling vector, nutation vector, rotation vector, target size, observation while and rotation inertia to measure precision is evaluated.To simulate the movement parameter conveniently, this paper chooses the symmetrical satellite as the target, but this term is not used in the mass center measurement, the method proposed in this paper is applicable to non-cooperative target all the same.