A novel 3D precision displacement system of large travel

nanometer level and displacement measurement by itself has been developed. The precision displacement system is designed with modular structure. The driving mechanisms of three directions are adopted with identical design structure and called as X direction

Y direction and Z direction one-dimensional worktable respectively. The dual-stage actuators of coarse and fine driving have been applied in the precision displacement system in X

Y and Z directions and three sets of metrology gratings are installed in X

Y and Z directions respectively. In this system

the driving mechanisms of X direction and Y direction are placed horizontally with upper and lower stacked structure

the driving mechanism of Z direction is placed vertically. In every direction

AC servomotor coordinating with precision lead screw and linear guide actuate the coarse driving

piezoelectric micro-displacement actuator coordinating with flexure hinge actuate the fine driving

a set of metrology grating is used for the displacement measurement of the coarse driving and fine driving. Therefore the need of large travel

nanometer level and displacement measurement by itself of the displacement system can be satisfied. The structure design of the displacement system is introduced. The displacement resolution

the metrology principle and the motion performance of this displacement system are also analyzed in details. Thereby the theoretical basis for displacement system design is provided.