Research On Macro Positioning Method Of Heavy Haul Workbench For Dividing System Of Large And High Precision Diffraction Grating Ruling Engine

With continuous development of the spectral detection technology,the grating features excellent spectroscopic behavior and can satisfy the use requirements in all bands,so it gradually replaces the prism and becomes one of the extensively applied spectroscopic devices in the world today.As a famous expert from America in the grating manufacturing field,Professor George R.Harrison gives such comment on the grating,“It's difficult for us to find a unit part like the diffraction grating which can provide such rich information to plentiful scientific fields.” This comment incisively summarizes that the grating has been playing an irreplaceable role in multiple important scientific technology fields.Since the first grating was born,the grating has been developing for more than 200 years and the method for its manufacturing has changed dramatically.As one of the most ancient methods for manufacturing gratings,mechanical engraving is still the unique choice for manufacturing some special gratings,such as the infrared grating with large spacing and a large depth-to-width ratio and the echelle grating with higher resolution capability.To obtain better light gathering and resolution capability in celestial observation and other related fields,the above two types of gratings with a larger caliber are preferred.The best solution for this issue lies in that a grating ruling engine with maximum stroke shall be built.With the increase of the grating ruling area,the building difficulty will grow exponentially,so it is very challenging to build one such grating ruling engine.The operation precision of a grating ruling machine has a larger impact on the performance indicators of gratings.Positioning precision and oscillation angle precision of the dividing system of a grating ruling engine with large stroke will directly affect performance indexes such as gratings' diffractive wavefront quality,stray light level and ghost-strength.The operation precision of the dividing system shall be ensured for a good grating.Although the dividing system adopts the design concept of macro-micro dual driving,the final precision is determined by the micro positioning stage.The operation precision of the macro positioning stage is also very important according to the related control theory.The workbench component of a large-stroke grating ruling engine is characterized by a mammoth mass,so it is difficult to ensure the operation precision of the macro positioning stage.This paper mainly carries out research on the macro positioning implementation method for a grating ruling engine with large stroke to reload the workbench of its dividing system.This paper mainly involves the following contents:First,the general design plan of the dividing system and design method of the critical kernel components of the large-stroke grating ruling engine.The paper proposes the general design plan of the dividing system of the large-stroke grating ruling engine by taking consideration to “reload”,“high precision” and “large stroke”,and designs in detail the screw-nut pair and double V-type roller guide pair for the positioning precision and oscillation angle precision,puts forward one open-close-type nut structure for real-time compensation of the intermediate diameter error and transmission accuracy improvement,optimize the roller quantity of the roller guide pair,and conducts the finite element analysis of the statics deformation of the double V-type roller guide pair under actual operation conditions.Secondly,ultraprecise grinding and detection method of the screw-nut pair.To guarantee the positioning precision of the macro positioning stage of the dividing system,the screw-nut pair shall be grinded in an ultraprecise manner.The ultraprecise grinding of the screw-nut pair shall be based on the error detection method with very high precision.The existing transmission accuracy detection method cannot truly detect the transmission accuracy of the nut to the screw shaft,so a new transmission accuracy detection method is proposed to eliminate the axial movement error in real time and the Abbe error is corrected.This method features very high measurement precision,so it is very suitable for the guidance on grinding of the screw nut pair.Thirdly,the ultraprecise grinding,detection,installation and resetting method of the double V-type guide rail pair.The oscillation angle of the macro positioning of the dividing system is mainly implemented by the double V-type guide rail pair.To improve the guide precision of the double V-type guide rail pair,it is necessary to adopt the means of grinding.To reduce the machining difficulty and improve its precision,a machining plan is proposed to first process separately and then combine together.Like machining of the screw nut pair,the grinding of a single guide rail is also based on the error detection method with very high precision,so we propose a guide rail linearity error detection method based on the autocollimator.For the later combination and resetting phase,a guide rail parallelism detection method based on the laser interferometer and autocollimator is proposed.The contactless measurement method is used in two detection methods,so they can realize very high measurement precision.Fourthly,to verify the general operation precision of the macro positioning stage of the dividing system,related tests are performed.The operation precision of the grating macro positioning step with different grating densities is tested.The test results show that the dividing system of the grating ruling engine can realize higher positioning precision and oscillation angle positioning angle at the macro positioning step and can satisfy the requirements of the further closed feedback control for the operation precision at the macro positioning stage.