Dynamic Parameter Identification Of Space Robot

This article is mainly discussed with the issue of dynamic parameter identification on space robot. It presents space robot and robotics-based method for modeling and identification algorithm of inertia properties of spacecraft separately. The content of the study is mainly through establishing dynamic model, using different identification algorithm for dynamic parameter identification, then testing the stability of the identification algorithm through simulation.Here we mainly study the following points:The article establishes a dynamic model of space robot system Firstly, the derivation of equation uses Lagrange's method in the momentum conservation equation constraints, and gives the equation of the Jacobian matrix representation.Secondly, the article concerns with parameter identification method for inertial parameters of the unknown object handled by manipulators on a free-flying space robot. Under the condition that no external forces and torques are applied to the space robot. The article is based on the conservation principle of linear and angular momentum. The feature of the proposed method is to use the kinematical information. The kinematical information is measured by sensors installed on the satellite base or on the other part of the system. When the measurements contain some sensor noises, the parameters have been estimated with rather small error. Finally, the feasibility of the method is demonstrated by numerical simulation.Lastly, the article discusses a robotics-based method for on-orbit identification of the inertia properties of spacecraft. The method makes use of an onboard robotic arm to change the inertia distribution of the spacecraft system. As the result of the inertia redistribution, the velocity of the spacecraft system will change correspondingly. Since the velocity change is measurable and the inertia change of the robotic arm is precisely computable, the inertia parameters of the spacecraft body become the only unknown in the momentum equations of the spacecraft system and hence, can be identified. In order to treat the problem as a linear identification problem, which is much easier to solve, a two-step approach is introduced. The first step is to identify the mass and mass center of the spacecraft; and the second step is to identify the inertia tensor of the spacecraft. Finally, the feasibility of the method is demonstrated by numerical simulation.