Fast cooperative obstacle-avoidance path planning for multiple space manipulators

For a space manipulator with multiple links, joints, and degrees of freedom, it is necessary to comprehensively consider the motion state of each link to make the manipulator reach the target position. In this regard, this study proposes a fast cooperative obstacle-avoidance path planning method for multiple space manipulators. The proposed method can quickly determine the obstacle-avoidance path of each link in multiple space manipulators with multiple degrees of freedom. In this method, first, the geometric relationship between the space manipulator and the target is used to constrain the range of motion of each link in the space manipulator. Thereafter, the Bezier shape-based (SB) method is used to generate the obstacle-avoidance motion path of each of these links. By comparing the results of the Bezier SB method, the finite Fourier series (FFS) SB method, and the Gauss pseudospectral method (GPM), the effectiveness and superiority of the proposed method are verified. The simulation results show that the Bezier SB method yields better results with shorter computation time than the FFS SB method. The results obtained using the Bezier SB method are employed as the initial values for the GPM. And the computation time for the Bezier SB method is less than 2.5% that of the GPM, while yielding results with a performance index difference of approximately 2%. Thus, the proposed method is proved to be considerably effective for quickly determining the cooperative obstacle-avoidance path of multiple manipulators in complex on-orbit service tasks.