The Development of a Real Time Recursive Frequency Based Active Chatter Controller

Author(s):  
Sun Kim ◽  
Karl B. Ousterhout

Abstract In most machining processes, large amounts of energy are needed to accomplish the machining operation. When this energy is transmitted through a structure that has minimal damping characteristics, such as a lathe or a milling machine, self sustained oscillations (chatter) can develop. When chatter develops, it can be viewed as a basic performance limitation of the machine tool. In order to suppress the chatter, a real-time controller using digital signal processing techniques has been implemented. This paper discusses a novel method for the real time computation of the transfer function of the machine tool-workpiece combination and illustrates how a real-time active chatter controller can be designed and integrated into existing machine tools to overcome this performance limitation.

Author(s):  
Karl B. Ousterhout

Abstract In most machining processes, large amounts of energy are needed to accomplish the machining operation. When this energy is transmitted through a structure that has minimal damping characteristics, such as a lathe or a milling machine, self sustained oscillations (chatter) can develop. When chatter develops, it can be viewed as a basic performance limitation of the machine tool. In order to suppress the chatter, a real-time controller using digital signal processing techniques has been implemented. This paper discusses a novel way of computing the transfer function of the machine tool-work piece combination and illustrates how a real-time active chatter controller could be designed and integrated into existing machine tools to overcome this performance limitation. Currently, experimental verification of the analytical work is being pursued.


2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Zhehuang Huang ◽  
Yidong Chen

Exon recognition is a fundamental task in bioinformatics to identify the exons of DNA sequence. Currently, exon recognition algorithms based on digital signal processing techniques have been widely used. Unfortunately, these methods require many calculations, resulting in low recognition efficiency. In order to overcome this limitation, a two-stage exon recognition model is proposed and implemented in this paper. There are three main works. Firstly, we use synergetic neural network to rapidly determine initial exon intervals. Secondly, adaptive sliding window is used to accurately discriminate the final exon intervals. Finally, parameter optimization based on artificial fish swarm algorithm is used to determine different species thresholds and corresponding adjustment parameters of adaptive windows. Experimental results show that the proposed model has better performance for exon recognition and provides a practical solution and a promising future for other recognition tasks.


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