Forward Kinematics Analysis of 6-PORO Secondary Mirror Alignment Mechanisms

This paper presents a new 6 degree of freedom(6-DOF)secondary mirror alignment mechanism for space optical payload. The moving platform is connected to the base by six kinematic branch chains, each branch chain is composed of Prismatic joint P, two Offset RR-hinges and Revolute joint R. Compared to the parallel platforms with universal joint configuration, the forward kinematics problem of the parallel platform with Offset RR-hinges is much more complicated due to the existence of dependent joint variables. In this paper, the numerical solution of the forward kinematics is presented and solved by the Newton-Raphson method. The simulation results are carried out to verify the accuracy and efficiency of the forward kinematics solution. The prototype has been developed and the proposed procedure is verified by the experimental test.