Studies Of High-precision Roll Measurement Methods For Simultaneous Measurements Of Multi-degree-of-freedom Errors

The study of multi-degree-of-freedom errors measurement methods and techniques has already become a common concern in many fields such as mechanical manufacturing and instruments, and it is also a difficult measurement problem that has been not yet solved properly, especially for roll measurement.Based on analyzing the relevant references home and abroad, the optical measurement methods for roll error are studied in details in this dissertation, several optical methods for roll error of machine tool are put forward, and the corresponding systems are developed, the reliability of the methods and the systems are verified through a variety of experiments and the research work. Furthermore, based on a FDMS, several corresponding optical methods for simultaneously measuring multi-degree-of-freedom errors are put forward.The innovative research achievements achieved in the dissertation are as follows:1. A novel roll measurement method based on a one-dimensional grating is presented. In this method, a grating is used as an element for measuring the roll, and the direction of the collimated laser is used as the reference, and the differential measurement based on the±1order diffractive beams is adopted. This method is characterized by simple structure and small target.2. A novel roll measurement method based on a rectangular-prism is presented. A rectangular-prism with splitting film is used as an element for measuring the roll. The spatial position of the collimated laser is used as the reference and the differential measurement is adopted based on two parallel beams coming from the rectangular-prism.3. A novel roll measurement method based on the pentagonal prisms and retro-reflectors is presented. In this method, the measuring beam is splitted into two parallel beams by a pair of pentagonal prisms and a pair of retro-reflectors is used as the element for measuring the roll. The spatial position of the collimated laser is used as the reference and the differential measurement is adopted based on two parallel beams. Furthermore, an improved method with double measurement resolution and common-path structrue is put forward.4. The systems based on the above three methods are developed and the feasibility of the systems is verified by theoretical analysis and experiments. Theoretical analysis shows that error separation can be realized in the above three methods and the anti-interference ability of the system can be enhanced. The influence of the parallelism error is analyzed and discussed in detail. Due to the feature of error separation, a parallelism error measurement method adopting calibration method is put forward and applied in measurement experiments.