Abstract:  In order to avoid the scratches on the workpiece in the high hardness sphere grinding, the grinding force was got indirectly by measuring the motorized spindle current which is used as a feedback to control the grinding force of the high hardness sphere grinding. A fuzzy adaptive control optimization strategy based on dynamic threshold (DTFACO) was applied according to the features of the grinding force generated in the high hardness sphere grinding process. The current threshold can be auto obtained and rectified on line. The depth of cut and the swing angular speed which affect the grinding force can also be adjusted on line by fuzzy strategy to maintain the grinding process stable. The experimental results indicate that the fuzzy adaptive control optimization strategy based on dynamic threshold can decrease the roughness of the workpiece without decreasing the grinding efficiency. It can avoid the scratches on the workpiece in the high hardness sphere grinding.

Key words: high hardness sphere, grinding, dynamic threshold, fuzzy adaptive control optimization