A new family of spatial 3-DoF fully-parallel manipulators with high rotational capability

Most fully-parallel manipulators encountered today have a common disadvantage, i.e., their low rotational capability. To overcome such a difficulty, this paper focuses its attention on the proposal of a new family of three-degree-of-freedom (3-DoF) fully-parallel manipulators capable of high rotational capability. Parallelogram allows the output link to remain at a fixed orientation with respect to an input link, for which it has many unique roles, especially when creating a desirable DoF output in the design of parallel manipulators. The role of a parallelogram herein described, is used completely for the design of a new parallel manipulator family. In this family, the moving platform of a parallel manipulator is connected to the base by three non-identical legs. The fact that all joints involved in the rotational DoF are with single DoF guarantees the high rotational capability performance of the manipulators. The parallel manipulators proposed here have wide applications in industrial robots, simulators, micro-motion manipulators, parallel kinematics machines, and any other manipulation devices that a high rotational capability is needed. The research provides a new design methodology of novel parallel manipulators.