Dynamic parameter identification of free-floating space robots after capturing targets

The problem of dynamic parameter identification of a space robot system after capturing a target is investigated. An excitation trajectory design method is proposed to maintain persistent excitation for the dynamic parameter identification of a free-floating space robot. Firstly, the dynamic parameter identification model of the free-floating space robot is derived based on the momentum conservation principle. Next, finite Fourier series is used to parameterize the joint trajectories and the coefficients of the finite Fourier series are optimized for minimal condition number of the regression matrix as a constrained nonlinear optimization problem. The QR decomposition based recursive least-square algorithm is used to estimate the unknown dynamic parameters. The numerical simulation results show that the proposed excitation trajectory design method is able to improve the convergence rate and accuracy of the parameter identification for free-floating space robots.