Author
Haifeng Ma
Other affiliations: Northeastern University (China), Hong Kong Polytechnic University, Chinese Ministry of Education ...read more
Bio: Haifeng Ma is an academic researcher from Shandong University. The author has contributed to research in topics: Sliding mode control & Control theory. The author has an hindex of 5, co-authored 17 publications receiving 134 citations. Previous affiliations of Haifeng Ma include Northeastern University (China) & Hong Kong Polytechnic University.
Papers
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TL;DR: In this paper, the effect of cutting dynamics on the machining process is discussed and a thorough review on pros and cons of HSMC can help to effectively utilize its advantages and circumvent its shortcomings.
Abstract: The research and application of high speed metal cutting (HSMC) is aimed at achieving higher productivity and improved surface quality. This paper reviews the advancements in HSMC with a focus on the material removal mechanism and machined surface integrity without considering the effect of cutting dynamics on the machining process. In addition, the variation of cutting force and cutting temperature as well as the tool wear behavior during HSMC are summarized. Through comparing with conventional machining (or called as normal speed machining), the advantages of HSMC are elaborated from the aspects of high material removal rate, good finished surface quality (except surface residual stress), low cutting force, and low cutting temperature. Meanwhile, the shortcomings of HSMC are presented from the aspects of high tool wear rate and tensile residual stress on finished surface. The variation of material dynamic properties at high cutting speeds is the underlying mechanism responsible for the transition of chip morphology and material removal mechanism. Less surface defects and lower surface roughness can be obtained at a specific range of high cutting speeds, which depends on the workpiece material and cutting conditions. The thorough review on pros and cons of HSMC can help to effectively utilize its advantages and circumvent its shortcomings. Furthermore, the challenges for advancing and future research directions of HSMC are highlighted. Particularly, to reveal the relationships among inherent attributes of workpiece materials, processing parameters during HSMC, and evolution of machined surface properties will be a potential breakthrough direction. Although the influence of cutting speed on the material removal mechanism and surface integrity has been studied extensively, it still requires more detailed investigations in the future with continuous increase in cutting speed and emergence of new engineering materials in industries.
78 citations
TL;DR: The findings demonstrated that the second order optimal weighted contribution rate has a high application value in the fault diagnosis of rub-impact and the new index shows better superiority.
71 citations
TL;DR: This paper presents the design, analysis, and verification of a novel reaching law for discrete-time sliding-mode control that has the capability to amend the control gains in a wise manner, further mitigate chattering, and guarantee a smaller width of the quasi-sliding-mode domain (QSMD).
Abstract: This paper presents the design, analysis, and verification of a novel reaching law for discrete-time sliding-mode control. The control gains of the reaching law are automatically regulated by the power function and the exponential term that dynamically adapts to the variation of the switching function. The reaching law also employs the perturbation estimation and the difference function to redefine the change rate as the second-order difference of the uncertainty. Compared with previous methods, the proposed reaching law has the capability to amend the control gains in a wise manner, further mitigate chattering, and guarantee a smaller width of the quasi-sliding-mode domain (QSMD). In order to describe the system dynamics in the reaching phase and the sliding phase with respect to control gain values, both the decrement band and the QSMD (ultimate band) of the proposed reaching law are theoretically analyzed. The reaching steps for the switching function to converge toward the sliding surface are also obtained. The effectiveness of the proposed method is verified through numerical simulations and experimental investigations on a piezoelectric actuator.
47 citations
TL;DR: Different from existing similar works, the presented new reaching law has the ability to obtain a quasi-sliding mode (QSM) with an adjustable order $O(T^{n+ 1})$ boundary layer and can be guaranteed and the chattering can be further mitigated.
Abstract: In this paper, a novel dead zone sliding mode reaching law with disturbance compensation is developed for uncertain discrete-time systems. The reaching law is established based on the dead zone function and a high-order disturbance compensator, which estimates and compensates the disturbance by the high-order difference function. The exponential function, which is constructed based on the switching function, is employed to regulate the control gains. Different from existing similar works, the presented new reaching law has the ability to obtain a quasi-sliding mode (QSM) with an adjustable order $O(T^{n+ 1})$ boundary layer. Hence, much smaller ultimate magnitude of the QSM domain (QSMD) can be guaranteed and the chattering can be further mitigated. Moreover, system dynamics in and out the decrement band and the QSMD is theoretically analyzed. Numerical simulations are employed to demonstrate the superiority of the developed new method.
28 citations
TL;DR: A multi-condition identification method based on sensor fusion is proposed by fusing multi-source heterogeneous data with different spatial time–frequency distributions and shows that the proposed method can identify the multi-milling condition composed of chatter and tool wear failure.
24 citations
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22 Oct 2007
TL;DR: The fifth edition of "Numerical Methods for Engineers" continues its tradition of excellence and expanded breadth of engineering disciplines covered is especially evident in the problems, which now cover such areas as biotechnology and biomedical engineering.
Abstract: The fifth edition of "Numerical Methods for Engineers" continues its tradition of excellence. Instructors love this text because it is a comprehensive text that is easy to teach from. Students love it because it is written for them--with great pedagogy and clear explanations and examples throughout. The text features a broad array of applications, including all engineering disciplines. The revision retains the successful pedagogy of the prior editions. Chapra and Canale's unique approach opens each part of the text with sections called Motivation, Mathematical Background, and Orientation, preparing the student for what is to come in a motivating and engaging manner. Each part closes with an Epilogue containing sections called Trade-Offs, Important Relationships and Formulas, and Advanced Methods and Additional References. Much more than a summary, the Epilogue deepens understanding of what has been learned and provides a peek into more advanced methods. Approximately 80% of the end-of-chapter problems are revised or new to this edition. The expanded breadth of engineering disciplines covered is especially evident in the problems, which now cover such areas as biotechnology and biomedical engineering. Users will find use of software packages, specifically MATLAB and Excel with VBA. This includes material on developing MATLAB m-files and VBA macros.
578 citations
TL;DR: A three-stage SSL approach using data augmentation (DA) and metric learning is proposed for an intelligent bearing fault diagnosis under limited labeled data to demonstrate that the proposed method can perform better in bearing fault diagnosed under limited labeling samples than existing diagnostic methods.
141 citations
TL;DR: A deep learning-based fault diagnosis method is proposed, exploring additional unsupervised data which are generally easy for collection and achieves promising diagnostic performance on the semi-supervised learning tasks with few labeled data, but also is well suited for pure un supervised learning problems.
96 citations
TL;DR: A class weighted adversarial neural network is proposed to encourage positive transfer of the shared classes and ignore the source outliers in a challenging partial transfer learning problem using deep learning-based domain adaptation method.
92 citations
TL;DR: An improved direct torque control (DTC) with sliding mode controller and observer is developed to reduce the torque ripples of a four-phase SRM.
Abstract: The industrial application of the switched reluctance motor (SRM) is limited by its high torque ripples caused by the doubly salient structure. In this article, an improved direct torque control (DTC) with sliding mode controller and observer is developed to reduce the torque ripples of a four-phase SRM. First, a sliding mode controller based on a new reaching law is developed for designing a sliding mode speed controller (SMSC) for the DTC system. An antidisturbance sliding mode observer (ADSMO) is then proposed and combined with the SMSC to build a composite antidisturbance speed control strategy. Moreover, detailed simulation validations are carried out to reveal the effectiveness of the new reaching law, SMSC and ADSMO. Finally, experiments are conducted to verify the performance of the proposed SMSC–ADSMO in a DTC system with a four-phase SRM prototype.
69 citations