Intelligent Guideways to Improve Servo Control Performance of NC Machine Tools

1.两轴进给试验台接触式智能导轨的研制智能导轨是一种在导轨上装有闸瓦的滚动导轨。通过控制制动力，可以动态地控制导轨上的摩擦。我们开发了一个测试台的两个轴进给驱动与建议的智能导轨，以评估其有效性。采用高速电子阀的气动执行器控制制动器。特别是在新型高速、高加速度数控机床中，结构振动是一个关键问题，对闭环稳定性和轮廓精度有着重要影响。通过在进给驱动系统中采用智能导轨，可以改善这种结构振动的阻尼特性。通过实验台的实验研究，验证了智能导轨对结构低频振动的动态阻尼作用，以及对系统闭环响应的显著改善.进给驱动系统阻尼控制方案的比较研究为了解决进给驱动系统中的振动问题，例如机器的结构振动或滚珠丝杠的纵向振动，人们提出了各种阻尼控制方案。特别是，相对速度反馈控制方案的有效性进行了数学分析和比较不同的设置。基本上，该方案实现了工作台的线速度和伺服电机的旋转速度之间的差的附加反馈回路。相对速度可以反馈到伺服电机控制系统或直接反馈到工作台。为了将相对速度直接反馈到转台，可以采用智能导轨，对各种类型的相对速度控制方案进行了理论、仿真和实验对比研究。

1. Development of the contact-type Intelligent Guideway on a test stand of a two-axis feed drive The Intelligent Guideway is a roller guideway with brake shoes installed on the guide rail. By controlling the braking force, one can dynamically control the friction on the guideway. We developed a test stand of a two-axis feed drive with the proposed Intelligent Guideway to evaluate its effectiveness. A pneumatic actuator with using a high-speed electronic valve is used to control brakes. Particularly in latest high-speed, high-acceleration NC machine tools, the structural vibration is a critical issue that has a significant effect on the closed-loop stability and contouring accuracies. By employing the Intelligent Guideway in feed drive systems, the damping characteristics of such structural vibration can be improved. Experimental studies on the test stand validated the dynamic damping given by the Intelligent Guideway to low-frequency structural vibrations, and the significant improvement in the system's closed-loop response.2. Comparison studies of damping control schemes for feed drive systems In order to address vibration issues in feed drive systems such as the machine's structural vibration or the longitudinal vibration of the ball screw, various damping control schemes have been proposed. In particular, the effectiveness of the relative velocity feedback control scheme was mathematically analyzed and compared with different setups. Basically, this scheme implements an additional feedback loop of the difference between the linear velocity of the table and the rotational velocity of the servo motor. The relative velocity can be feedbacked to either the servo motor control system or directly to the table. In order to feedback the relative velocity directly to the table, the Intelligent Guideway can be used.Theoretical, simulation, and experimental comparison studies were conducted with various types of relative velocity control schemes.