الفهرس | Only 14 pages are availabe for public view |
Abstract The high accuracy, performance, stability, and dexterity of industrial robots are the main aims of designers and manufacturers, one of the effective factors to achieve the goal is the stability of the robot structure, the determination of the dynamic structural characteristics which can cosidered be the primary step to evaluate the performance also unlock the knowledge of amendment and improvement of the structure to get the optimum design. This thesis aims to evaluate the dynamic structural performance of three degrees of freedom parallel robot machine tools and study the influence of the platform dimension change on the performance of the parallel robot and modifications suggestions according to obtained results. Firstly, The fifteen models with different platform dimensions were modeled using Solid works software and exported to Ansys finite element (FE) software, the modeled systems were used to obtain dynamic characteristics from the frequency response curve (FRF) and modal analysis, experimental modal analysis was applied to the models using a data acquisition system. The natural frequencies and damping ratios for all models were collected. The results were correlated to evaluate the system performance and verify the accuracy of the two methods, also the effect of using damping in FEM was studied. The modifications were applied to update the specified models according to the maximum deformation location results, the model’s components (Platform, Links, and Joints) were replaced on Solid works and finite element software with other types to study the effect of changing parallel robot elements on the machine performance. The results give a clear view to designers and operators about the range of resonance frequencies that must be avoided during the selection of machining operation, furthermore provide the scope of errors between the used methods, and supply a valuable guide to evaluate the quality of the structural integrity of the parallel robot and present a proper guide to the redesign methodology. |