Stiffness analysis of a hybrid manipulator applied to a multi-dimensional vibration isolator

A hybrid manipulator is investigated in this paper, which is applied to a multi-dimensional (MD) vibration isolator. The vibration isolator and this hybrid manipulator are described firstly. Then the stiffness model is presented based on the screw theory method considering actuations and constraints simultaneously. When modeling, the hybrid manipulator is decomposed into two subsystems and the overall Jacobian matrices of them are derived assuming the other one is rigid. Then stiffness model of the entire system can be obtained with the linear superposition principle. Further, a generalized Jacobian matrix of constraints is proposed in this paper. Finally, the stiffness is evaluated by utilizing the compliances in different directions and the extremum values in workspace.