Research on the key technique for numerical control grinding arbitrary n-polygon shafts

Though analyzing the structure characteristics of arbitrary n-polygon non-circular sections, the mathematical formulas among the characteristic parameters were set up, and the theorem for designing this kind of sections was deduced by mathematical induction method. Based on mechanistic transmission principle, the control theorem for the numerical control (NC) grinding of arbitrary n-polygon non-circular sections and the control model for the multi-coordinate motion were built. The real-time interpolation algorithm was presented based on central angle division, and the method of acceleration-deceleration according to the curvature of surface was given. The dynamic model of the AC position servo system of grinding n-polygon non-circular sections is set up by experiment identification, and its parameter adjustment method is also studied. Then a feedforward control strategy is analyzed systematically, the tracking performance and contour error of the feedforward tracking controller for grinding n-polygon non-circular sections were deeply studied on the view of qualitative and quantitative analysis, the results show that the feedforward tracking control method is good in contour tracking and precision. Then a NC machine tool for grinding n-polygon non-circular sections was developed. The test results of the grinded parts showed that the section profiles accorded to the design demands; the roughness was less than 0.32 μm and the dimensional accuracy was within 8 μm. The results prove that the proposed theorems and method can effectively direct the design and manufacture of the polygonal non-circular connection.