Research On The Non-orthogonal Measurement Instrument For Large-scale Metrology

With development of the aerospace engineering,the ocean vessel and the automobile manufacturing,the large-scale metrology becomes a crucial area for modern industry.However,the conventional large-scale measurement machines,such as theodolite,total station and laser tracker,need cooperative targets or manual collimation to achieve a high precision measurement.What’s worse,their measurement accuracy highly relies on their structure orthogonality,which increases their expenditure.To solve this conflict,we have proposed the so-called non-orthogonal instrument.This thesis starts with the introduction of the general structure of the sensor unit of the non-orthogonal instrument,and then analyzes its abstract model,a pivoting machine with three skew lines.These lines are named as “vertical axis”,“horizontal axis” and “sight axis”,and their initial spatial position are named as internal parameters,which are calibrated by a higher precision instrument.The calibration method for internal parameters and the kinematic models of the sensor unit are two of the key points of our research.Next,for two different applications,this thesis proposed two different non-orthogonal measurement instruments named as “non-orthogonal theodolite system”(N-Theodolite)and “non-orthogonal total station system”(N-TS).We developed specific calibration methods for each instrument.And since the system parameters of N-Theodolite indicate the spatial relationship between two sensor units,it is called external parameters specifically.In addition,we found the pointing accuracy of the non-orthogonal instrument varies with different poses.So an accuracy improving method is proposed to improve the measurement accuracy of both systems.Finally,the simulations and experiments validate the measurement accuracy of non-orthogonal instruments and prove their feasibility for industrial application.