37 research outputs found
Motor Current Characterisation Based on Modulation Signal Bispectrum for Online Monitoring of Machining Operations
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Current Analysis Using a Modulation Signal Bispectrum for Machining Status Monitoring
No full textUniversal lathes currently have a place in manufacturing industry. Its processing status monitoring is an urgent problem to be solved because it is related to the quality of produced products. Traditional monitoring methods mainly use vibration sensors to monitor a lathe. This paper proposes the use of a modulated signal bispectrum (MSB) method to analyse current signals of a AC motor, which can monitor the machining state of a lathe connected with a motor. It applies MSB to instantaneous current signals measured step by step in turning experiments of different cutting tools to obtain accurate modulation characteristics and their evolution behavior with a change of workpiece size and cutting depth, to realize the monitoring of machining status. Results show that MSB is more effective than envelope spectrum analysis in extracting the characteristic values of treatment states.</p
Study on Condition Monitoring of Lathe Cutting State under Various Cutting Conditions Based on Motor Current Signature Analysis
No full textLathe machining occupies a large proportion in modern production and processing, which affects the machining accuracy of the workpiece and results in vibration and noise of the machine tool. To improve the efficiency of lathe cutting state monitoring, this paper presents a new method on studying the monitoring of lathe tool, with Motor Current Signal Analysis (MCSA) as the main research method, the characteristics of stator's working current are selected as the analysis object. Three cutting depths, 1mm, 2mm, and 3mm are respectively performed on the same workpiece material, and the cutting conditions are blunt tool and sharp tool. The frequency characteristic of the current is analyzed the under various cutting conditions mentioned above and the internal relation of the current variation and the cutting condition is presented as the conclusion of this paper, by which provides a new idea for the research of conditions monitoring and fault diagnosis in field operation on lathe tool.</p
A Review of Fault Diagnosis Methods for Marine Electric Propulsion System
No full textWith the rapid development of power electronics technology and the proposal of intelligent ships, electric propulsion systems on ships are becoming more and more widespread. As the power source for ship navigation, timely and accurate diagnosis and prediction of faults of electric propulsion system play a vital role in the operation safety of ships. This paper summarises the common faults of electric propulsion systems, reviews the latest developments and applications of fault diagnosis techniques based on fault signal analysis in electric propulsion system fault diagnosis, and discusses the advantages and disadvantages of typical methods in the light of the latest literature and current research problems. The paper concludes by proposing future trends in fault diagnosis and prediction for ship electric propulsion systems.</p
