Research On Installation And Position Measurement Technology Of Nuclear Fusion Device

With the rapid development of nuclear fusion science in China,it has promoted the research and installation of nuclear fusion devices.At present,Tokamak is the mainstream in China.Due to the higher technical parameters,the size of nuclear fusion devices has also become larger.Nowadays,the difficulty of high-precision positioning and installation restricts the research and development of large-scale installations.Since the traditional measurement method is difficult to meet the installation accuracy requirements of the current device,the emergence and development of laser tracker has solved this problem.The laser tracker is a mobile measuring device,which has the advantages of wide measuring range,high accuracy,easy portability,easy operation,flexible station setting,etc.,and can adapt to a more complex measuring environment.Therefore,it is very suitable for installation and measurement of nuclear fusion devices.First,this article introduces some measurement systems suitable for measuring large-size objects in space.By comparing the measurement range,accuracy and station flexibility of various measurement systems,the laser tracker is suitable for the installation and measurement of nuclear fusion devices.It also describes the development of laser trackers at home and abroad,and introduces the measurement principles of laser trackers and the main sources of measurement errors in detail.The principle of coordinate system transformation is explained and implemented with python program,so that the error magnitude of single coordinate transformation can be obtained.On this basis,the measurement error conforming to the laser tracker is added to simulate the accuracy of the transfer station.According to the requirements of the measurement plan,there are multiple transfer stations,which will result in cumulative errors.According to the requirements of the measurement plan,the cumulative error will occur in the case of multiple transfers.It can be determined by simulation.In the three aspects of the selection of common points,the selection of transfer stations and the data calculation after a unified coordinate system,look for Appropriate algorithm to reduce error.Then the simulation is used to verify the effectiveness of the algorithm,and it is used to simulate the establishment of a reference network,and the simulation accuracy and design accuracy are compared to verify the feasibility of the networking procedure.According to the installation environment and design requirements of the nuclear fusion device,formulate the corresponding measurement plan.This includes how to set up the reference network and select the location of the station.When setting up the reference network,the reference points are distributed on the wall and the cement base considering the environment of the installation site.The location of the station is mainly distributed around the installation position of the device,which can simultaneously measure the target measurement point and the reference point on the device.According to the measurement data of each station on the reference point during the installation of the nuclear fusion device,a reference network is formed and combined with the measurement data on the central column to form an assembly coordinate system.Transform the measurement data of the vacuum chamber and the polar field coils of each station to the assembly coordinate system.By calculating the coordinate values of each measuring point of the component in the assembly coordinate system,the technical parameters such as its installation height,coaxiality and mid-plane error are solved.The results show that the installation of the vacuum chamber and the polar field coil meets the design requirements.