Sensorless Cutting Force Estimation in Large Scale Ball-Screw-Driven Machine Tool

Abstract:

The cutting force is widely regarded as being the most valuable information when observing a metal cutting process. Considering practicability, indirect cutting force measurement methods which forego additional sensors have been studied in academic field. Disturbance observer-based cutting force estimation method was known as a typical example, and its validity was verified in linear motor driven stage. However, accurate cutting force estimation is still difficult in ball-screw driven stage because of non-linear friction and resonance. In this study, feasibility of sensorless cutting force estimation was verified by using large scale commercial machine tool. Considering that the motion of rotational and translational elements independently, cutting force observer (CFOB) was modeled as two-degree-of-freedom system. The CFOB was mounted to control systems of both stage and spindle head which were driven by ball-screw and servo motor. While friction force and torque have non-linear position dependence, high repeatability was confirmed. Thus, their non-linearity could be attenuated by identifying friction force and torque beforehand machining operation. From experimental results, it was shown that tooth-pass frequency and second harmonics component of the cutting forces could be estimated accurately by using the CFOB. The results were acquired from control systems of both stage and spindle head.

• Periodical: Advanced Materials Research (Volume 1136)
• Pages: 645-650
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.1136.645
• Online since: January 2016
• Authors: Yuki Yamada*, Yasuhiro Kakinuma, Takamichi Ito, Jun Fujita, Atsushi Tada, Makoto Sagara
• Keywords: Ball-Screw-Driven System, Cutting Force, Cutting Force Observer, Disturbance Observer, Non-Linearity, Process Monitoring

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