Angle measurement is the basic problem of mechanical testing theory and technology. High-precision angle measuring sensor is the core component that is irreplaceable for scientific research, advanced manufacturing and test measurement. In this paper, for the long-term technical problems of difficult to suppress the shaft axis error of the circular grating angle measuring sensor, the size and precision are difficult to reconcile, a new concept of multi-grating angle measuring sensor is proposed, and the error of the sensor itself, installation error, electronic subdivision error, and multi-grating measurement are studied. The angle sensor suppresses the shafting error and establishes a simulation model. A multi-grating angle measuring sensor experimental system was built. The experimental results show that the angle error of the multi-grating angle measuring sensor is 134.32"". The proposal of multi-grating angle measuring sensor provides a new way for mechanical angle measurement theory and method.
The shafting error has a great influence on the measurement accuracy of the laser tracker. Based on the error expression form, a mathematical model is established for the eccentricity error of the shafting system, and the simulation analysis is carried out. The tilting error of the shafting system is obtained from the angle of the geometric angle and the moiré fringe respectively. A specific analysis was carried out. A laser tracker angle measuring system was built to analyze the shafting error in the system and correct the shafting error. The experimental results show that the original error of the laser tracker angle measurement is 189.31", and the corrected angle error is 127.13", which provides a theoretical basis for the highprecision measurement of the laser tracker.
The effective application of high performance measurement technology can greatly improve the large-scale equipment manufacturing ability. Therefore, the geometric parameters measurement, such as size, attitude and position, requires the measurement system with high precision, multi-function, portability and other characteristics. However, the existing measuring instruments, such as laser tracker, total station, photogrammetry system, mostly has single function, station moving and other shortcomings. Laser tracker needs to work with cooperative target, but it can hardly meet the requirement of measurement in extreme environment. Total station is mainly used for outdoor surveying and mapping, it is hard to achieve the demand of accuracy in industrial measurement. Photogrammetry system can achieve a wide range of multi-point measurement, but the measuring range is limited and need to repeatedly move station. The paper presents a non-contact opto-electronic measuring instrument, not only it can work by scanning the measurement path but also measuring the cooperative target by tracking measurement. The system is based on some key technologies, such as absolute distance measurement, two-dimensional angle measurement, automatically target recognition and accurate aiming, precision control, assembly of complex mechanical system and multi-functional 3D visualization software. Among them, the absolute distance measurement module ensures measurement with high accuracy, and the twodimensional angle measuring module provides precision angle measurement. The system is suitable for the case of noncontact measurement of large-scale equipment, it can ensure the quality and performance of large-scale equipment throughout the process of manufacturing and improve the manufacturing ability of large-scale and high-end equipment.
Before the star sensor completes the attitude measurement task with the launch of the spacecraft, it must be calibrated on the ground. In order to meet the requirements of high precision star sensor calibration, according to some specific problems of optical structure of conventional ground calibration equipment in response to large aperture, long focal length and wide spectrum requirements, an off-axis collimator was designed as a collimating optical system, and the image quality was evaluated, and mechanical structure of the off-axis collimator was also designed in detail. Control technology of star brightness was researched and analyzed, and a set of lighting control system is designed. Analysis and test results show that a variety of seven consecutive magnitudes can be simulated by the lighting control system, and the simulated error between neighboring magnitudes is less than 8‰, to meet the current high precision star sensor calibration technical requirements.
In a rotating angle measuring system, errors of grating sensor, installation and rotor run-outs will affect angle measuring error. The error caused by rotor run-outs is usually the biggest and the hardest to eliminate of them. To improve the accuracy, the table should be fabricated precisely, thus, the table system will be complicated and expensive. This paper provides a method to solve the challenge by using two gratings in the same table, whose gratings respectively grooved on end face and side face. The error mechanism of end face and side face caused by axial and radial rotor run-outs by were deduced. It can be concluded from the analysis that end face grating is sensitive when radial rotor run-outs happens, side face grating is sensitive when axial rotor run-outs happens. Due to the conclusion, combined type gratings with one end face grating and one side face grating can be used to restrain the error caused by Rotor Run-outs of table.