A Neural Network Approach for Force and Contour Error Control in Multi-Dimensional End Milling Operations

The problem of controlling the average resultant cutting force together with the contour error in multi-dimensional end milling operations is considered in this study. Two sets of neural networks are used in the control system. The first set is used to specify the feed rate to maintain a desired cutting force. This feed rate is resolved along the feed axes using a parametric interpolation algorithm so that the desired part shape is obtained. The second set is used to make corrections to the feed rate components specified by the parametric interpolation algorithm to minimize the contour error caused by the dynamic lag of the closed-loop servo systems controlling the feed drives. In addition, the control system includes a feedforward input to compensate for static friction effects. Experimental results are presented for machining two-dimensional circular slots and a three-dimensional spherical surface to show the validity of the proposed approach.

[1]  A. Galip Ulsoy,et al.  Model Reference Adaptive Force Control in Milling , 1989 .

[2]  Masayoshi Tomizuka,et al.  On the design of digital tracking controllers , 1993 .

[3]  Wen Feng Lu,et al.  Force Control in Two-Dimensional End Milling Operations Using Recurrent Neural Networks , 1995 .

[4]  Y. C. Shin,et al.  Control of Cutting Force for End Milling Processes Using an Extended Model Reference Adaptive Control Scheme , 1996 .

[5]  Masayoshi Tomizuka,et al.  Low Velocity Friction Compensation and Feedforward Solution Based on Repetitive Control , 1993 .

[6]  Carlos Canudas de Wit,et al.  A survey of models, analysis tools and compensation methods for the control of machines with friction , 1994, Autom..

[7]  Snehasis Mukhopadhyay,et al.  Adaptive control of nonlinear multivariable systems using neural networks , 1993, Proceedings of 32nd IEEE Conference on Decision and Control.

[8]  Ali Galip Ulsoy,et al.  DYNAMIC MODELING FOR CONTROL OF THE MILLING PROCESS. , 1985 .

[9]  Barry K. Fussell,et al.  Adaptive control of force in end milling operations— an evaluation of available algorithms , 1991 .

[10]  M. Tomizuka,et al.  Adaptive Force Control of Two Dimensional Milling , 1992, 1992 American Control Conference.

[11]  K. Srinivasan,et al.  Optimal Contouring Control of Multi-Axial Feed Drive Servomechanisms , 1989 .

[12]  Jun-Ho Oh,et al.  Model Reference Adaptive Control of the Milling Process , 1983 .

[13]  Masayoshi Tomizuka,et al.  Feedforward Tracking Controller Design Based on the Identification of Low Frequency Dynamics , 1993 .