The Research Of X-Y Type Space Two-dimensional Pointing Mechanism's Error

The space two-dimensional pointing mechanism is a space equipment with searching,capturing and tracking capabilities,which is the key mechanism of space remote sensing satellite.With the continuous improvement of the requirement for space tasks,improving the precision of two-dimensional pointing mechanism is the key to improving the performance of the whole satellite.In this paper,the influence of static deviation and dynamic deviation of the space two-dimensional pointing mechanism is analyzed.First of all,the two-sate model of the “contact-separation” is being used to describe the kinematic pair with clearance,the non-linear hertz model is being used to describe the contact force of the kinematic pair and the Coulomb model is chosen to be the model of the friction of the kinematic pair.Based on the Newton-Euler method,the dynamic equation of the space two-dimensional pointing mechanism is established.Secondly,put forward the space two-dimensional pointing mechanism manufacture error analysis method,namely to find out the sources produced in the design,production and processing of the mechanism,and classify the error sources and superimpose them on the three axes.The static erros model of the space twodimensional pointing mechanism is created by D-H method.The static errors model is calculated by MATLAB software,the surface graphs of the error with the change of the position and posture of the mechanism are obtained and the influence of each error source on the mechanism accuracy is analyzed.Then,the dynamics of the space two-dimensional pointing mechanism with joint clearance are calculated by MATLAB software,and the curves of contact deformation of motion pair,velocity,angular velocity and displacement of the mechanism are obtained and compared when different conditons are given.The influence of the joint clearance,stiffness and damping on the accuracy and stablility of the mechanism is analyzed.Finally,the deviation compensatory model of the space two-dimensional pointing mechanism is established by perturbation deviation offset and its principle.The simulation gets compensation quantity of movement variable and new deviation values,The feasibility of the compensation method is verified.