Waheed Ur Rehman, Jiang Guiyun, Luo Yuan Xin, Wang Yongqin, Nadeem Iqbal, Shafiq UrRehman and Shamsa Bibi
This paper’s aim is modeling and simulation of an advanced controller design for a novel mechatronics system that consists of a hydrostatic journal bearing with servo control. The…
Abstract
Purpose
This paper’s aim is modeling and simulation of an advanced controller design for a novel mechatronics system that consists of a hydrostatic journal bearing with servo control. The proposed mechatronic system has more worth in tribology applications as compared to the traditional hydrostatic bearing which has limited efficiency and poor performance because of lower stiffness and load-carrying capacity. The proposed mechatronic system takes advantage of active lubrication to improve stiffness, rotor’s stability and load-carrying capacity.
Design/methodology/approach
The current work proposes extended state observer-based controller to control the active lubrication for hydrostatic journal bearing. The advantage of using observer is to estimate unknown state variables and lumped effects because of unmodeled dynamics, model uncertainties, and unknown external disturbances. The effectiveness of the proposed mechatronic system is checked against the traditional hydrostatic bearing.
Findings
Proposed mechatronics active hydrostatic journal bearing system is checked against traditional hydrostatic journal bearing. It is found that novel active hydrostatic journal bearing with servo control has good tribology performance factors such as stiffness, less rotor vibration, no wear and friction under starting conditions and high load-carrying capacity under different conditions of spindle speed, temperature, initial oil pressure and external disturbance. The result shows that proposed mechatronics system has more worth in rotary tribology applications.
Originality/value
The current manuscript designs a novel active hydrostatic journal bearing system with servo control. The mathematical model has advantages in term of estimating unknown state variables and lumped effects because of unmodeled dynamics, model uncertainties and unknown external disturbances. The result shows improvement in dynamic characteristics of a hydrostatic journal bearing under different dynamic conditions.
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Keywords
Kangqu Zhou, Chen Yang, Lvcheng Li, Cong Miao, Lijun Song, Peng Jiang and Jiafu Su
This paper proposes a recommendation method that mines the semantic relationship between resources and combine it with collaborative filtering (CF) algorithm for crowdsourcing…
Abstract
Purpose
This paper proposes a recommendation method that mines the semantic relationship between resources and combine it with collaborative filtering (CF) algorithm for crowdsourcing knowledge-sharing communities.
Design/methodology/approach
First, structured tag trees are constructed based on tag co-occurrence to overcome the tags' lack of semantic structure. Then, the semantic similarity between tags is determined based on tag co-occurrence and the tag-tree structure, and the semantic similarity between resources is calculated based on the semantic similarity of the tags. Finally, the user-resource evaluation matrix is filled based on the resource semantic similarity, and the user-based CF is used to predict the user's evaluation of the resources.
Findings
Folksonomy is a knowledge classification method that is suitable for crowdsourcing knowledge-sharing communities. The semantic similarity between resources can be obtained according to the tags in the folksonomy system, which can be used to alleviate the data sparsity and cold-start problems of CF. Experimental results show that compared with other algorithms, the algorithm in this paper performs better in mean absolute error (MAE) and F1, which indicates that the proposed algorithm yields better performance.
Originality/value
The proposed folksonomy-based CF method can help users in crowdsourcing knowledge-sharing communities to better find the resources they need.
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Keywords
Xueying Zhou, Wentao Sun, Zehui Zhang, Junbo Zhang, Haibo Chen and Hongmei Li
The purpose of this study is to study the quantitative evaluation method of contact wire cracks by analyzing the changing law of eddy current signal characteristics under…
Abstract
Purpose
The purpose of this study is to study the quantitative evaluation method of contact wire cracks by analyzing the changing law of eddy current signal characteristics under different cracks of contact wire of high-speed railway so as to provide a new way of thinking and method for the detection of contact wire injuries of high-speed railway.
Design/methodology/approach
Based on the principle of eddy current detection and the specification parameters of high-speed railway contact wires in China, a finite element model for eddy current testing of contact wires was established to explore the variation patterns of crack signal characteristics in numerical simulation. A crack detection system based on eddy current detection was built, and eddy current detection voltage data was obtained for cracks of different depths and widths. By analyzing the variation law of eddy current signals, characteristic parameters were obtained and a quantitative evaluation model for crack width and depth was established based on the back propagation (BP) neural network.
Findings
Numerical simulation and experimental detection of eddy current signal change rule is basically consistent, based on the law of the selected characteristics of the parameters in the BP neural network crack quantitative evaluation model also has a certain degree of effectiveness and reliability. BP neural network training results show that the classification accuracy for different widths and depths of the classification is 100 and 85.71%, respectively, and can be effectively realized on the high-speed railway contact line cracks of the quantitative evaluation classification.
Originality/value
This study establishes a new type of high-speed railway contact wire crack detection and identification method, which provides a new technical means for high-speed railway contact wire injury detection. The study of eddy current characteristic law and quantitative evaluation model for different cracks in contact line has important academic value and practical significance, and it has certain guiding significance for the detection technology of contact line in high-speed railway.
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Lijun Meng, Xinyu Li and Xin Tan
A fiber Bragg grating (FBG) sensor was designed to measure the door gap of automobile bodies.
Abstract
Purpose
A fiber Bragg grating (FBG) sensor was designed to measure the door gap of automobile bodies.
Design/methodology/approach
The gap sensor was designed through a combination of the sliding wedge and cantilever beam, involving a magnetic force installation and arc structure of the force transmission point. Moreover, the sliding block adopted an anti-magnetic and wear-resistant material and the temperature compensation of the two FBGs was conducted. The magnetic force and contact stress of the sensor were examined to ensure that the sensor exhibited a certain magnetic attraction force and fatigue life. The performance of the gap sensor was examined experimentally.
Findings
The sensor could measure gaps with dimensions of 5 mm to 11 mm, with a sensitivity and measurement accuracy of 150.9 pm/mm and 0.0063% F.S., respectively. Moreover, the sensor exhibited a small gap sensitivity, with a repeatability error of 0.15%, anti-creep properties and magnetic interference abilities.
Originality/value
The sensor is compact and easy to install, as well as use for multiple sensor locations, with a maximum size of 43 mm, a mass of 26 g and installation type of magnetic suction. It can be used for high-precision static and dynamic measurements of the door inner clearance with a resolution of 0.013 mm to improve the efficiency of internal clearance on-line analysis and assembly quality inspection.
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Waheed Ur Rehman, Xinhua Wang, Yingchun Chen, Xiaogao Yang, Zia Ullah, Yiqi Cheng and Marya Kanwal
The purpose of this paper is to improve static/dynamic characteristics of active-controlled hydrostatic journal bearing by using fractional order control techniques and optimizing…
Abstract
Purpose
The purpose of this paper is to improve static/dynamic characteristics of active-controlled hydrostatic journal bearing by using fractional order control techniques and optimizing algorithms.
Design/methodology/approach
Active lubrication has ability to overcome the unpredictable harsh environmental conditions which often lead to failure of capillary controlled traditional hydrostatic journal bearing. The research develops a mathematical model for a servo feedback-controlled hydrostatic journal bearing and dynamics of model is analyzed with different control techniques. The fractional-order PID control system is tuned by using particle swarm optimization and Nelder mead optimization techniques with the help of using multi-objective performance criteria.
Findings
The results of the current research are compared with previously published theoretical and experimental results. The proposed servo-controlled active bearing system is studied under a number of different dynamic situations and constraints of variable spindle speed, external load, temperature changes (viscosity) and variable bearing clearance (oil film thickness). The simulation results show that the proposed system has better performance in terms of controllability, faster response, stability, high stiffness and strong resistance.
Originality/value
This paper develops an accurate mathematical model for servo-controlled hydrostatic bearing with fractional order controller. The results are in excellent agreement with previously published literature.
Peer review
The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-07-2020-0272