Motion Planning For Free-Floating Space Robot

With the development of space technology, space robots especially to free-floating space robots (FFSR) are applied widely. The FFSR consists of a space vehicle and manipulators fixed on the space vehicle. It can float freely in space and take the place of astronauts to work on orbits. The space vehicle is not controlled at work, so the fuel used to control the vehicle location and orientation can be saved and long the life of the space robot. In this paper, kinematics modeling, path planning of free-floating space robots are studied.Firstly, the history and current status of the development of space robot at home and abroad are summed up. The theory of the robots based on ground is applied in the description of the attitude and the foundation of the D-H coordinate system of space robots.And then the kinematics model of free-floating space robot is deduced. This model can easily show velocity mapping relations among base, end tool point and joints of space robot. The characteristics of space robot, i.e. base attitude disturbance characteristic, nonholonomic and the workspace of free-floating space robot are discussed. The work discussed above is the theoretical foundation of path planning for free-floating space robot.Finally, a path planning methodology for free-floating space robot systems is developed, which is on the purpose of fuel optimal. The method is based on mapping the angular momentum to a space where it can be satisfied trivially. Smooth and continuous functions such as polynomials are employed driving the system to a desired configuration. The methodology allows endpoint Cartesian location control, and simultaneous control of the spacecraft's attitude. At the end the examples are presented.