High Speed and High Precision Feed Drive of NC Machine Tools by Dual Actuation

为了实现高速、高生产率的加工，高速进给驱动器被引入到加工中心中。高导程滚珠丝杠驱动器通常用于实际应用中，因为它们具有成本效益并且对诸如切削力的干扰具有鲁棒性。然而，滚珠丝杠驱动器由于通常用于高速进给驱动器中的滚珠或滚子导轨的低阻尼而遭受振动。本研究探讨一种双作动驱动器，其在驱动工作台中具有子作动器，以及传统的滚珠丝杆驱动机构。在我们的研究中使用的实际致动器是线性电机和摩擦控制指南（智能指南）。通过仿真和实验得到以下事实。(1)对工作台致动器（主动阻尼器）和电动机（常规速度反馈）的直接速度反馈不能独立地控制振动极点。反之，电机和转台的相对速度反馈可以独立控制振动杆。(2)从运动控制的角度来看，对工作台致动器的速度反馈可以控制零位。(3)二质量振动系统的阻尼比由惯性比和速度反馈增益决定。双作动器的相对速度反馈可在较宽的惯性比范围内提供高阻尼。(4)由于相对速度反馈给工作台驱动器不增加导向力，因此可以降低主运动电机的功率。(5)如果子致动器存在饱和，则与线性反馈控制相比，非线性速度反馈控制可以提供更好的阻尼性能以抑制振动。结论（1）-（3）有助于高种子和高精度进给驱动器的设计性能，结论（3）-（5）有助于整个系统的成本效益和紧凑性。

High speed feed drives are being introduced to machining centers for aiming high speed and high productive machining. High lead ballscrew drives are generally used in practical applications, as they are cost-effective and robust to disturbances such as cutting forces. However, ballscrew drives suffer from vibration due to low damping of ball or roller guideways which are commonly used in high speed feed drives. This study deals with a dual actuation drive, which has sub actuators in the drive table as well as conventional ballscrew drive mechanism. Actual Actuators used in our study are a linear motor and a friction control guide (an intelligent guide) . Following facts are obtained by simulations and experiments.(1) Direct velocity feedback to the table actuator (active damper) and to motor (conventional velocity feedback) can't control vibration poles independently. On the contrary, relative velocity feedback of motor and table can control vibration pole independently.(2) Velocity feedback to the table actuator can control zero positions from motion control view.(3) Damping ratio of 2 mass vibration system is decided by inertia ratio and velocity feedback gain. Relative velocity feedback to dual actuators provides high damping in wide range of inertia ratio.(4) As relative velocity feedback to the table actuator doesn' t increase guide force, the power of main motion motor can be lowered.(5) If saturation of a sub actuator exists, nonlinear velocity feedback control may offer better damping performance to suppress vibration compared to linear feedback control. The conclusions (1)-(3) contribute to design performance of high seed and high precision feed drive and the conclusions (3)-(5) contribute to cost-effectiveness and compactness of the total system.