Singular configuration research of RRRP manipulators in space

End-effector will lose one or some independent component motion when serial mechanism moves to singular configuration, which leads to decreasing of degree of Freedom. That not only affects the finish of expectant motion, but also makes the control of manipulator difficult. A general solver is set up to deal with the problem of the expressing of the joint screws of open series robot. Then the solver is applied to find the singular configuration to the RRRP mechanism. The condition of singular configuration is attained. And the linear correlation of axis screws is analyzed by using Grassmann line geometry method. The results provide an important reference to the Utilizing and avoiding of singular configuration when designing and controlling the manipulators in space.