Abstract:

Aiming at the issue of serious local lift errors in the cam grinding process, we present a cam lift error compensation method based on the weighted support vector machine (WSVM). The circle rate of symbols is  used to judge whether the cam lift error values are continuous, and then the relationship of angle and weighted value between discrete points and adjacent points is established. The values of cam lift error are fitted by the WSVM. The new cam lift values are obtained by subtracting the fitted cam lift values from the original cam lift values. Then, the number of smooth points of the cam lift values can be maximized by automatically adjusting the weight coefficients according to the circle rate, therefore, the optimal cam lift values can be obtained. The algorithm is simulated and carried on the CNC camshaft grinder YTM833616. The results show that the cam lift error is reduced from 0.059mm to 0.011 mm, and the surface roughness is decreased from 0.32 μm to 0.25 μm, which demonstrates the good effect of the proposed method.

Key words: cam grinding;cam lift error;weighted support vector;machine curve fitting;robustness estimate