Study Of High-precision Positon Pose Measurement Technique Based On Laser Tracker

In recent years,high precision position-pose measurement technology is a hot research area in precise engineering manufacturing.With the development of large-scale industrial manufacturing in China,and the continued support and investment to the equipment manufacturing industry in our country,the high-end industrial equipment is being developed rapidly.Meanwhile,as one of the embodiments of the development of this field,measurement technology is getting more and more attention,and the demand on measuring is getting higher and higher.Due to the structural diversity and the motion complexity of measuring objects,the purpose of measuring is not only to obtain higher measurement precision of the location information,but also get their position-pose information and corresponding time information.The measurement means and methods are various,but most of them can only be applied for a specific application environment.The installation and detection for large industrial equipment is lack of a unified measuring method,which can satisfy the high accuracy and dynamic measuring demand.Based on the summary and analysis of the existing position measurement methods,combining the requirements in the construction of big scientific projects,in weaponry testing and in manned spaceflight engineering,this paper proposes a set of laser tracker based position-pose measurement methods.The main contents of this paper are as follows:1.The existing position-pose measuring technique is summarized,including the defining methods of common coordinate systems and theories for static or dynamic position-pose measurement.Taking the joint survey of iGPS and theodolite as an example,cubic prism based position-pose measuring method of multisensory combination is studied,and the measurement principle and calculation model of dedicated position-pose measuring accessory for laser tracker are analyzed and deduced.2.This paper presents a static position-pose measuring method to realize survey and alignment for cubic prism based on laser trackers.The mainstream approach of measuring the position-pose of cubic prism is high precision electronic theodolite.However,the measurement process is complicated,time-consuming and susceptible to artificial observation.Based on the reflectance measurement principle when measuring a mirror with a laser tracker,a method is designed to measure the position-pose of a cubic prism.By combining error analysis and experiments,the reliability and feasibility of this method is verified,and its advantages over classical methods are analyzed.3.To get higher precision position,the adjustment model of 3D trilateration survey based on the distance observations of multiple laser trackers is explored.The influence of coordinates' initial value on adjustment results is analyzed.And a method to calculate the coordinates' initial value using common point transformation is proposed,the calculated results is verified by comparing with the measured value of laser interferometer.To calculate position and pose simultaneously,the adjustment model of 3D trilateration survey is explored.Since the weight of observation determined by experience is far from enough,a new weighting method is proposed based on Helmert variance component estimation.By using posterior information of horizontal angle,vertical angle and distance observation,the weight of all observations are adjusted,which makes the weight more reasonable and helps to achieve better adjustment result.The optimization design method for control network of multiple laser trackers is discussed.Based on genetic algorithm,choosing proper objective function and constraint conditions,the optimization method and procedures of multiple laser trackers' control network are designed,and its precision is verified.4.A high-accuracy measuring method of time synchronization for multiple laser trackers is proposed,and a synchronization trigger is designed and developed.By utilizing GNSS standard time source is to discipline high stability thermostatic vibrator,accurate local time service is achieved,and the measuring method of time synchronization for multiple laser trackers is studied and realized.Error sources of time synchronization are analyzed,a test method is designed to comprehensively test the time synchronization precision.5.The computing model of multiple laser trackers based dynamic position-pose measurement is established,and a set of position measurement and data processing methods are presented.Data preprocessing includes gross error detection and removal,data interpolation and data filtering.According to the characteristics of synchronous measurement data of multiple laser trackers,based on state-constraint conditions,gross error removal method and Kalman filtering method are proposed to process the data,and the methods are tested in experiments.6.Position-pose measurement software is developed.This software can implement the functions of multiple laser trackers on-line control,control network construction,synchronous trigger measurement and real-time position-pose calculation,and it has been applied in practical projects.