On-Line Energy-Based Milling Chatter Detection

2018 ◽  
Vol 140 (11) ◽  
Author(s):  
Hakan Caliskan ◽  
Zekai Murat Kilic ◽  
Yusuf Altintas
Keyword(s):  
Fourier Transforms ◽  
Energy Operator ◽  
Forced Vibrations ◽  
Chatter Detection ◽  
Line Energy ◽  
Natural Modes ◽  
Chatter Vibrations ◽  
On Line ◽  
Milling Chatter ◽  
Periodic Components

Milling exhibits forced vibrations at tooth passing frequency and its harmonics, as well as chatter vibrations close to one of the natural modes. In addition, there are sidebands, which are spread at the multiples of tooth passing frequency above and below the chatter frequency, and make the robust chatter detection difficult. This paper presents a novel on-line chatter detection method by monitoring the vibration energy. Forced vibrations are removed from the measurements in discrete time domain using a Kalman filter. After removing all periodic components, the amplitude and frequency of chatter are searched in between the two consecutive tooth passing frequency harmonics using a nonlinear energy operator (NEO). When the energy of any chatter component grows relative to the energy of forced vibrations, the presence of chatter is detected. The proposed method works in discrete real time intervals, and can detect the chatter earlier than frequency domain-based methods, which rely on fast Fourier Transforms. The method has been experimentally validated in several milling tests using both microphone and accelerometer measurements, as well as using spindle speed and current signals.

Investigation on Adaptive Filter for On-Line Detection and Active Control of Chatter Vibration in Milling Process

2019 ◽  
Author(s):  
Shaoke Wan ◽  
Xiaohu Li ◽  
Wenjun Su ◽  
Jun Hong
Keyword(s):  
Active Control ◽  
Adaptive Filter ◽  
Rotation Frequency ◽  
Milling Process ◽  
Spindle Speed ◽  
Line Detection ◽  
Spindle Rotation ◽  
On Line ◽  
Milling Chatter ◽  
Periodic Components

Abstract On-line detection and active control of chatter vibration have always been important issues in milling process respectively. To some extent, the signals obtained with sensors determine the performance of on-line detection and active control of chatter. However, due to the characteristics of milling process, the obtained signals are mainly consisted with spindle rotation frequency and its harmonics, and the chatter components are usually submerged by these stable harmonics, imposing negative effects for the detection and active control of milling chatter. Then, it is highly needed to design a real-time filter to filter out the spindle rotation frequency and its harmonics. In this paper, an adaptive filter is designed to filter out the spindle speed related components. Moving average (MR) model and adaptive filter theory is utilized to estimate these periodic components. The influence of filter order and step size factor on the filter characteristics are also analyzed. Considering that the filter order needs to be adjusted under different cutting conditions, which will alter the filter’s performance, an improved adaptive filter is proposed. Experiments are also performed and the experimental results show that, not only the spindle speed related components can be filtered out effectively, but the chatter frequency components are amplified with appropriate initial step factor, which is beneficial for the detection of milling chatter at early stage. Meanwhile, the periodic components caused by the installation error and the other spindle speed related components can be effectively filtered out real-timely, preventing the saturation of actuator caused by these stable components.

A Model Based Computationally Efficient Method for On-Line Detection of Chatter in Milling

2013 ◽  
Author(s):  
Lei Ma ◽  
Shreyes Melkote ◽  
James Castle
Keyword(s):  
Efficient Method ◽  
Chip Thickness ◽  
Line Detection ◽  
Chatter Detection ◽  
Computationally Efficient ◽  
Model Based ◽  
Force Signal ◽  
On Line ◽  
Regeneration Effect ◽  
Milling Chatter

This paper presents a model-based computationally efficient method for detecting milling chatter in its incipient stages. Based on a complex exponentials model for the dynamic chip thickness, the chip regeneration effect is amplified and isolated from the cutting force signal for early chatter detection. The proposed method is independent of the cutting conditions. With the aid of a one tap adaptive filter, the proposed method is also found to be able to distinguish between chatter and the dynamic transients in the cutting forces due to sudden changes in workpiece geometry and tool entry/exit. The proposed method is experimentally validated.

On-Line Chatter Detection Using Wavelet-Based Parameter Estimation

2000 ◽  
Author(s):  
Taejun Choi ◽  
Yung C. Shin
Keyword(s):  
Parameter Estimation ◽  
Estimation Algorithm ◽  
Cutting Process ◽  
High Dimensional ◽  
Detection Accuracy ◽  
Chatter Detection ◽  
Ml Estimation ◽  
On Line ◽  
Low Dimensional ◽  
Low Dimensional Dynamics

Abstract A new method for on-line chatter detection is presented. The proposed method characterizes the significant transition from high dimensional to low dimensional dynamics in the cutting process at the onset of chatter. Based on the likeness of the cutting process to the nearly-1/f process, this wavelet-based maximum likelihood (ML) estimation algorithm is applied for on-line chatter detection. The presented chatter detection index γ is independent of the cutting conditions and gives excellent detection accuracy and permissible computational efficiency, which makes it suitable for on-line implementation. The validity of the proposed method is demonstrated through the tests with extensive actual data obtained from turning and milling processes.

On Line Distributions of Kelvin Sources

1964 ◽  
Vol 8 (04) ◽  
pp. 45-52
Author(s):  
E. O. Tuck
Keyword(s):  
Free Surface ◽  
Physical Properties ◽  
Velocity Potential ◽  
Fourier Transforms ◽  
Point Sources ◽  
Straight Line ◽  
On Line ◽  
New Form ◽  
Line Of Singularities

The velocity potential for the flow due to point sources distributed arbitrarily along a straight line near to or at a linearized gravitational free surface is obtained in a new form by use of Fourier transforms. Such a method of representing the potential facilitates the determination of its behavior near to the line of singularities; this behavior is derived formally and its physical properties discussed. A brief illustration is given of a method of using this result in o theory for the motion of a slender ship.

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