A Study on Preview Control of Machine Tools by Means of a Predicted Cutting Torque Pattern

研究了在有限切削扭矩约束下，通过控制进给速度实现切削效率最大化的问题。我们指出自适应控制方案不能解决这个问题，因为它需要一个团队时间。在本研究中，提出了基于切削仿真对切削扭矩预测的预估算法。以下是得到的重要结果。1)建立了基于工件模型的切削仿真系统，以估计切削过程中切削扭矩的变化。2)主轴转速波动信号能清晰显示切削扭矩的变化，有效检测刀具故障。3)根据预测的切削扭矩，可以计算出维持有限恒定切削扭矩所需的进给速度。考虑进给驱动系统的动态响应，提出了从期望进给速率得到输入进给速率的预估算法。4)搭建了一个由加工中心和个人计算机组成的实验系统，对该方法的有效性进行了评价。切削实验表明，即使工件几何形状发生突变，切削力矩也能保持恒定。

This research deals with the problem of maximizing cutting efficiency by controlling the feed rate with the constraint of limited cutting torque. We pointed out that the adaptive control scheme does not provide a solution to this problem because it requires a Teaming time. In this research, the preview algorithm is proposed based on the prediction of a cutting torque patted by cutting simulation. The followings are important results obtained.1)A cutting simulation system based on the workpiece, inodel has been developed to estimate the change in cutting torque in the course of the cutting operation.2)Fluctuation signal of a spindle rotational speed clearly shows the change in the cutting torque, and is efficient to detect tool failure.3)The desired feed rate patted to maintain the limited and constant cutting torque can be calculated from the predicted cutting torque patted. The preview algorithm has been developed to obtain the input feed rate patted from the desired feed rate patted by considering the dynamic response of the feed drive system.4)An experimental system which consists of a machining center and a personal computer has been constructed to evaluate the effectiveness of the method. The cutting experiments show that the cutting torque was kept at a constant value even at an abrupt change of the workpiece geometry.