Construction method of coordinate frame based on similar material simulation experiment platform and precision analysis

In similar material simulation experiment, it is an important process to obtain the displacement field of the subject investigated scientifically, fast and precisely, and the construction of local coordinate system with high precision is the foundation of obtaining spatial information of subject points.Based on this, this paper puts forward a practical construction method of coordinate frame in similar material simulation experimental platform, meanwhile establishes the coordinate frame error model, obtaines the calculation formula of the point mean square error in the coordinate frame, and analyzes and validates the model through the design of the field experiment.The results show that measuring error increases linearly with the increase of length correction and temperature, respectively.In different measuring precisions of angle, the point mean square error of the coordinate frame, along with the increase of length correction or temperature, has a trend of increase with decrease at first and has its minimum, and the point mean square error decreases with the improvement of instrument measuring precision.The calculated theoretical mean square errors of intending-set points in the coordinate frame are respectively ±0.633 mm and ±0.558 mm.Nevertheless, mean square errors of corresponding points of the field experiment are ±0.409 mm and ±280 mm, which are better than the theoretical calculated values.