The Research Of Space Two-dimensional Pointing Mechanism’s Pointing Precision

The space heavy precision two-dimensional pointing mechanism is a space equipment with large dynamic pointing range and tracking capabilities, which is used in space optical camera, remote sensing satellite and so on. What the most important indicators of this equipment is its pointing precision. So researching in the factors that affect machine’s pointing accuracy and how to improve the pointing accuracy become the most concern of contemporary scholars. Owing to the heavy and precision characteristics of this machine and the gravity difference between the manufacturing debugging phase and the working phase, the influence of gravity to pointing accuracy is studied in this paper.The kinematic pair deformation in this machine has an important pact on the pointing accuracy. Firstly, the finite element model of the kinematic pair in the two-dimensional pointing equipment is established. Using the classical theory of the finite element and the static analysis software, the distortion form in the overweight environment during launch and the deformation degree under different position in the standard gravitational environment is analyzed. Owing the result shows the deformation is elastic, so we can only consider the deference between the gravity on the ground and the microgravity on the space. Then, the effect of deformation on kinematic pair clearance and how the change of the kinematic pair clearance affect the pointing accuracy of this mechanism is also studied.The support deformation directly affects the pointing accuracy of this pointing machine. Secondly, the finite element model of support in this two-dimensional pointing mechanism is built. The form of support deformation in the overweight environment during launch is also simulated. Under the standard gravitational field, as the change of pitch axis and bearing axis, the change of the mechanism’s pointing error under the condition that the base is level fixed and vertical fixed are all analyzed. After calculating the optical axis deviation Angle under different pose state, a method of adjusting pointing accuracy is proposed.Finally, under the effect of gravity, how the support geometry structure, the material and the speed of the pith axis of the pointing mechanism affect the pointing accuracy is studied, providing the reference for the design of support framework, the selection of material and the speed of pitch axis in next stage.