Research On The Design Of The Intelligent "Variable Length" Photoelectric Reference Scale

The new laser electronic theodolite system provides a new way for the automatic measurement for the coordinates in the large space and size,because it has the function of laser targeting and servo drive.However,precision laser electronic theodolites are so strict in manufacturing process that they are expensive,which limits its application.So it is necessary to draw on the three axis structure mode of traditional theodolite,but breaking the orthogonal structure of the three axes,and develop a new non-orthogonal shafting "laser theodolite" measurement system.When the non-orthogonal shafting "laser theodolite" measurement system is set up,the determination of the space position and attitude between theodolites is the key to establish the mode of measurement system,which affects the accuracy of the results of the system measurement.In order to orientate the non-orthogonal shafting “laser theodolite” measurement system quickly and accurately,this paper proposes and studies a construction technology of intelligent “variable length” photoelectric reference scale based on high-precision photoelectric position sensitive detector.The study details are as follows:1.With the analysis of the coordinate measurement system in the large space and size and common directional reference scales at home and abroad,according to development of the high-precision photoelectric position sensitive detector,this paper proposes a construction technology of intelligent “variable length” photoelectric reference scale according to the non-orthogonal shafting "laser theodolite" measurement system.2.Two kinds of the orientation principle of traditional theodolite system are analyzed,which are precision aiming and bundle adjustment methods.On this basis,we propose the working principle of the non-orthogonal shafting "laser theodolite" measurement system and its orientation program and process,which identifies the necessity of the photoelectric reference scale.3.The basic theory of high-precision photoelectric position sensitive detector is studied in detail,which mainly includes the structure and principle of PSD,PSD equation and the principle of PSD detecting the center of gravity.On this basis,we propose and study overall design scheme of the intelligent “variable length” photoelectric reference scale,calibrate the spatial position relationship of the two PSDs and the selection of the material of the photoelectric reference rod.4.The hardware design of the intelligent “variable length” photoelectric reference scale is completed,including PSD signal processing module and wireless communication module.PSD signal processing module includes the analysis of the impact and elimination of interference signals,solution of PSD multi-channel signals and design of signal preprocessing circuit.Wireless communication module includes wireless communication technology,selection of radio frequency chip and design of wireless communication module based on n RF24E1.5.We validate the accuracy of the repeatability of PSD position detection and calibrate the spatial position relationship of the two PSDs.Experimental platform for the accuracy evaluation of photoelectric reference scale has been built and the feasibility of the scheme of the intelligent “variable length” photoelectric reference scale and the related technology is verified.At last,the cause of the error is analyzed.