Papers by Author: Lun Shi

Abstract: A comprehensive performance testing table of the constant velocity joint drive shaft assembly is discussed in this paper. This testing table is able to operate 9 testing items. The mechanical structure, the working principle, and the software system of the testing table is introduced respectively. Intelligent measuring method and LCOD technique is used in the system. System identification method is applied while designing the control system. An example of slip curve testing program is also given at this paper.

Abstract: A comprehensive performance testing table, on which 9 testing items can be done, of the constant velocity joint drive shaft assembly is developed. The principle of the system is introduced and the mechanical structure and the computer measuring and control system of it are discussed particularly. Some intelligent measuring methods, such as fuzzy method, are used in the system and an example of testing the slip curve characteristic of the joint assembly by fuzzy measuring method is presented in detail, including its membership function and fuzzy rules of fuzzy reasoning. The slip curve measured by traditional method compared with that by fuzzy method. The experimental results show that the measurement precision by fuzzy method is more accurate than that by the traditional one.

Abstract: Spindle thermal deformation is the main error source of many precision profile grinders. In this paper, the relationship between spindle temperature and either radial or axial thermal deformation is studied based on experiments. The placement and amount of temperature sensors are optimized. Then a kind of thermal error modeling method based on support vector machine is presented and applied in the modeling of thermal error of profile grinding. The result shows the model is robust and the on-line accurate prediction of grinding thermal error is realized based on monitoring of temperature rise of spindle. Finally, the error compensation strategy is discussed for further application of thermal error modeling.

Abstract: Because of the high precision in roundness, straightness and roughness, it is very difficult to machining the inner surface of injection nozzle. Honing machine is the main equipment for machining the injection nozzle. The key honing control techniques and honing test for injection nozzle on the developed high precision vertical honing machine are analyzed. The quantitative expansion，which is one of the most important feeding styles in honing process, is discussed in detail. Some machining tests on the developed honing machine are made and the work pieces of injection nozzles with inner surface Φ11mm are honed successfully with roundness tolerance less than 0.4μm, straightness tolerance less than 1μm and roughness tolerance less than 0.04μm.

Abstract: Present modeling algorithm for large-sized revolving parts’ camber can not ensure the smoothness, so a new modeling algorithm based on NURBS Curve was proposed in this study. In detail, the new modeling algorithm is as following: Firstly transfer these discrete points, which are measured along the part’s axial lead by equal distant, into a weighting unity sequence. Secondly filter this sequence by wavelet de-noising algorithm. Thirdly replace the discrete points’ amplitudes by the corresponding weights of filtered sequence, thus yield a group of new discrete points. Lastly calculate the control vertexes and weighting factors by local rational interpolation algorithm, and construct a spatial NURBS Curve through the new discrete points to obtain the model of large-sized revolving parts’ camber. It was experimentally confirmed that this model can represent drilling stem’s camber smoothly and improve its pressure straightening precision.