Abstract: In near future, multi-branch space robot system will be an important tool in the universe exploring. There are many differences between general serial/parallel robots and multi-branch space robot system. The multi-branch space robot system has its own features. A three-branch space robot system is proposed. Basing on the structure of the special three-branch space robot system and forward displacement solution of some parallel manipulator, the inverse displacement solution is derived to this system. Through this method, all the inverse displacement solutions of the three-branch space robot system can be obtained conveniently and rapidly.

Key words: Inverse displacement solution, Space robot, Three-branch