Dynamic analysis of space robot manipulator considering clearance joint and parameter uncertainty: Modeling, analysis and quantification

摘要

Clearance joint as an inevitable nonlinear factor in space robot manipulator modifies dynamic response of the mechanism, justifies deviations between predictions and measurements, and enhances sensitivity of mechanism response to parameter variation. The coupling of clearance joint and parameter uncertainty, therefore, would further significantly influence the kinematic accuracy and dynamic response of a space robot manipulator. In this paper, the dynamic performance of space robot manipulator with consideration of joint clearance and parameter uncertainty is analyzed. Quantification of parameter effect on the dynamic response is also presented. In the analysis, joint elements are modelled as colliding bodies, where the nonlinear contact force model and hybrid friction model are employed to describe the impact-contact phenomena. Motion equations of the mechanism are derived in which nonlinear forces are considered as external forces. Then, the Chebyshev polynomial method is introduced to explicate the relation between the mechanism response and parameters. Based on the Chebyshev polynomial method, dynamic response of the uncertain mechanism could be calculated through the use of interval algorithm, and a sensitivity analysis method is introduced to quantify the parameter effect. The dynamics of a space robot manipulator with joint clearance and parameter uncertainty is further investigated, where the clearance size and friction coefficients are taken as single and multiple uncertain parameters, and effects of the uncertainties on the manipulator response are quantified. This study could help for the design, analysis and test of a space robot manipulator with consideration of both clearance and uncertainty.