Research on pose error relations of parallel radiotherapy bed based on total differential method

摘要

On the purpose of meeting the requirement of precise radiotherapy, research for pose error relations of six degrees of freedom parallel radiotherapy bed was conducted by total differential method. At first, the error model of the radiotherapy bed taken by the closed-loop vector method was established to obtain the main factors which influenced the pose errors of the radiotherapy bed. Total differential method was performed on the error model to get the pose error relations and the main factors. Then, the sensitive parameters which had greater impact on pose errors and the sensitive direction of the pose errors of the radiotherapy bed could be obtained by analyzing when errors existed on condition of single branched chain and multiple branched chains. The result shows that the sensitive parameters and the sensitive directions, which can be used to guide the design precision and assembly precision of the parts, can provide a theoretical basis for the establishment of the calibration model and improve the accuracy of radiotherapy bed at last.