Research

4450 KiB

Open AccessArticle

Remote Servo Tuning System for Multi-Axis CNC Machine Tools Using a Virtual Machine Tool Approach

by Chien-Yu Lin and Ching-Hung Lee

Appl. Sci. 2017, 7(8), 776; https://doi.org/10.3390/app7080776 - 30 Jul 2017

Cited by 14 | Viewed by 8589

Servo systems affect the performances of machining in accuracy and surface quality for high speed and precision machine tools. This study introduces an efficient servo tuning technique for Computer Numerical Control (CNC) feed drive systems using particle swarm optimization (PSO) algorithm by virtual [...] Read more.

Servo systems affect the performances of machining in accuracy and surface quality for high speed and precision machine tools. This study introduces an efficient servo tuning technique for Computer Numerical Control (CNC) feed drive systems using particle swarm optimization (PSO) algorithm by virtual machine tool approach. The proposed approach contained a system identification phase and a servo tuning phase based on the same bandwidth for all axes feed drive systems. The PSO algorithm was adopted to obtain the system parameters and maximize the corresponding bandwidth. An efficient two-step servo tuning method based on gain and phase margins was proposed for high speed and precision requirements. All feed drive systems controller gains were optimized simultaneously for synchronization. A remote system called Machine Dr. was established for servo tuning and monitoring. Simulation and experimental results were introduced to illustrate the effectiveness of the proposed approach. Full article

(This article belongs to the Special Issue Selected Papers from the 2016 International Conference on Inventions)

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7748 KiB

Open AccessArticle

Vibration Control Design for a Plate Structure with Electrorheological ATVA Using Interval Type-2 Fuzzy System

by Chih-Jer Lin, Chun-Ying Lee and Ying Liu

Appl. Sci. 2017, 7(7), 707; https://doi.org/10.3390/app7070707 - 08 Jul 2017

Cited by 9 | Viewed by 5671

Abstract

This study presents vibration control using actively tunable vibration absorbers (ATVA) to suppress vibration of a thin plate. The ATVA is made of a sandwich hollow structure embedded with electrorheological fluid (ERF). ERF is considered to be one of the most important smart [...] Read more.

This study presents vibration control using actively tunable vibration absorbers (ATVA) to suppress vibration of a thin plate. The ATVA is made of a sandwich hollow structure embedded with electrorheological fluid (ERF). ERF is considered to be one of the most important smart fluids and it is suitable to be embedded in a smart structure due to its controllable rheological property. ERF’s apparent viscosity can be controlled in response to the electric field and the change is reversible in 10 microseconds. Therefore, the physical properties of the ERF-embedded smart structure, such as the stiffness and damping coefficient, can be changed in response to the applied electric field. A mathematical model is difficult to be obtained to describe the exact characteristics of the ERF embedded ATVA because of the nonlinearity of ERF’s viscosity. Therefore, a fuzzy modeling and experimental validations of ERF-based ATVA from stationary random vibrations of thin plates are presented in this study. Because Type-2 fuzzy sets generalize Type-1 fuzzy sets so that more modeling uncertainties can be handled, a semi-active vibration controller is proposed based on Type-2 fuzzy sets. To investigate the different performances by using different types of fuzzy controllers, the experimental measurements employing both type-1 fuzzy and interval type-2 fuzzy controllers are implemented by the Compact RIO embedded system. The fuzzy modeling framework and solution methods presented in this work can be used for design, performance analysis, and optimization of ATVA from varying harmonic vibration of thin plates. Full article

(This article belongs to the Special Issue Selected Papers from the 2016 International Conference on Inventions)

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3320 KiB

Open AccessArticle

Innovation of New Occlusion Devices for Cancers

by Hao-Ming Hsiao, Tzu-Yuan Lin, Chien-Erh Lin, Han-Yu Lee and Yi-Ping Wang

Appl. Sci. 2017, 7(5), 530; https://doi.org/10.3390/app7050530 - 19 May 2017

Cited by 1 | Viewed by 4935

Abstract

Liver cancer, a life-threatening disease, can be cured if found early. A common treatment for liver tumors that cannot be removed by surgery is hepatic artery embolization. It involves injecting small beads to block the blood flow towards cancer cells. In this paper, [...] Read more.

Liver cancer, a life-threatening disease, can be cured if found early. A common treatment for liver tumors that cannot be removed by surgery is hepatic artery embolization. It involves injecting small beads to block the blood flow towards cancer cells. In this paper, we propose the world’s first nitinol spherical occlusion device, which can be deployed in the upstream of an artery to reduce the blood flow to the downstream cancer cells. Finite element models were developed to predict the device’s mechanical integrity during manufacturing and deployment. Computational fluid dynamics were applied to simulate the device’s clinical occlusion performance. Simulation results suggested that devices with a metal density of 14–27% would reduce the average blood flow rate by 30–50%. A conceptual prototype was first cut by pulsed-fiber optic laser, and a series of expansions and heat treatments were used to shape the device to its final geometry. Flow experiments were conducted for proof of concept, and results showed that the spherical occlusion device successfully reduced the flow as designed. The occlusion device with the metal density of 27% was able to reduce 44% of flow, which agreed well with the simulation results. Full article

(This article belongs to the Special Issue Selected Papers from the 2016 International Conference on Inventions)

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8954 KiB

Open AccessArticle

Swirling Gas Jet-Assisted Laser Trepanning for a Galvanometer-Scanned CO₂ Laser

by Chao-Ching Ho, Ke-Ying Shen, Chang-Sheng Chen, Yuan-Jen Chang, Jin-Chen Hsu and Chia-Lung Kuo

Appl. Sci. 2017, 7(5), 502; https://doi.org/10.3390/app7050502 - 17 May 2017

Viewed by 5288

Abstract

Laser-drilled hole arrays are part of an important field that aim to improve efficiency without affecting the quality of laser-drilled holes. In this paper, a swirling gas jet was implemented to assist with laser trepanning for a galvanometer scanned CO₂ laser. The [...] Read more.

Laser-drilled hole arrays are part of an important field that aim to improve efficiency without affecting the quality of laser-drilled holes. In this paper, a swirling gas jet was implemented to assist with laser trepanning for a galvanometer scanned CO₂ laser. The proposed swirling gas jet is based on laser trepanning. This swirling gas jet nozzle was composed of four inlet tubes to produce the flow of the vortex. Then, the plume particles were excluded, and spatter on the surface of the workpiece decreased. Thus, this approach can mitigate the problem of overcooling. This study manipulated the appropriate parameter settings, which were simulated by computational fluid dynamics software ANSYS CFX. The proposed swirling gas jet can be used with galvanometer-based scanner systems to keep the laser beam from interference by spatter. In addition, a hollow position of the vortex was achieved by using the four inlet tubes, which resulted in pressure asymmetry in the nozzle and velocity distribution on the surface of the workpiece. The experiment verified that the depth of processing could be enhanced by 110% when trepanning at a scanning speed of 30 mm/s, and that the removal of volume could be enhanced by 71% in trepanning at a diameter of 1 mm by using a swirl assistant compared with a non-assisted condition. Furthermore, the material removal rate of the swirling jet increases when the machining area of the galvanometer-based scanner is larger. Full article

(This article belongs to the Special Issue Selected Papers from the 2016 International Conference on Inventions)

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2684 KiB

Open AccessArticle

Operational Temperature Effect on Positioning Accuracy of a Single-Axial Moving Carrier

by Kun-Ying Li, Win-Jet Luo, Jun-Zheng Huang, Yung-Chao Chan, Pratikto and Dini Faridah

Appl. Sci. 2017, 7(4), 420; https://doi.org/10.3390/app7040420 - 20 Apr 2017

Cited by 13 | Viewed by 4625

Abstract

This study investigated the ambient environmental temperature effect on the positioning accuracy of a periodically-moving carrier. The moving carrier was operated in an environmental chamber in which the operational temperature could be controlled by an air conditioning system. Different operational temperature modes, including [...] Read more.

This study investigated the ambient environmental temperature effect on the positioning accuracy of a periodically-moving carrier. The moving carrier was operated in an environmental chamber in which the operational temperature could be controlled by an air conditioning system. Different operational temperature modes, including a stable environment, a rise in temperature, a decline in temperature, summer daytime hours, and winter nighttime hours in terms of seasonal climate change in Taiwan, were generated within the environmental chamber by an air conditioning system to investigate the operational temperature’s effect on positioning accuracy. From the experimental measurements of a periodically-moving carrier, it is found that the operational temperature conditions can significantly affect the positioning accuracy of the moving carrier, especially in the case of an operational temperature decline. Under stable operational conditions, the positioning accuracy of the moving carrier can be considerably improved. In comparison to the case of an operational temperature decline, the positioning accuracy improvement can reach 29.6%. Moreover, the effect of the temperature distributions within the chamber on the positioning accuracy was further investigated. It was found that, with a parallel flow pattern in the chamber, the positioning accuracy can be further enhanced. Full article

(This article belongs to the Special Issue Selected Papers from the 2016 International Conference on Inventions)

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2416 KiB

Open AccessArticle

Extended Backstepping Sliding Controller Design for Chattering Attenuation and Its Application for Servo Motor Control

by Li-Hsin Chen and Chao-Chung Peng

Appl. Sci. 2017, 7(3), 220; https://doi.org/10.3390/app7030220 - 27 Feb 2017

Cited by 14 | Viewed by 4918

Abstract

This paper presents a robust backstepping design for motion control in the presence of model uncertainties and exogenous disturbances. The main difficulty in dealing with motion control is to reduce the effect of friction, which exists in the moving mechanism and induces nonlinear [...] Read more.

This paper presents a robust backstepping design for motion control in the presence of model uncertainties and exogenous disturbances. The main difficulty in dealing with motion control is to reduce the effect of friction, which exists in the moving mechanism and induces nonlinear behavior. In this study, the friction dynamic is considered as the external disturbance, and the proposed backstepping control algorithm is integrated with the sliding mode control, so that the effect of matching disturbances can be eliminated. The proposed approach guarantees the system asymptotic stability, globally, without significant chatter. Therefore, the developed algorithm can be realized for practical manufacturing motion control stages. Experiments including positioning and tracking controls are conducted to demonstrate the feasibility of the proposed method. Full article

(This article belongs to the Special Issue Selected Papers from the 2016 International Conference on Inventions)

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7502 KiB

Open AccessArticle

Nonlinear Integral Type Observer Design for State Estimation and Unknown Input Reconstruction

by Chao-Chung Peng

Appl. Sci. 2017, 7(1), 67; https://doi.org/10.3390/app7010067 - 14 Jan 2017

Cited by 9 | Viewed by 4914

Abstract

This paper is concerned with model-based robust observer designs for state observation and its application for unknown input reconstruction. Firstly, a sliding mode observer (SMO), which provides exponential convergence of estimation error, is designed for a class of multivariable perturbed systems. Observer gain [...] Read more.

This paper is concerned with model-based robust observer designs for state observation and its application for unknown input reconstruction. Firstly, a sliding mode observer (SMO), which provides exponential convergence of estimation error, is designed for a class of multivariable perturbed systems. Observer gain matrices subject to specific structures are going to be imposed such that the unknown perturbation will not affect estimate precision during the sliding modes; Secondly, to improve discontinuous control induced in the SMO as well as pursue asymptotic estimate precision, a proportional-integral type observer (PIO) is further developed. Both the design procedures of the SMO and PIO algorithms are characterized as feasibility issues of linear matrix inequality (LMI) and thus the computations of the control parameters can be efficiently solved. Compared with the SMO, it will be demonstrated that the PIO is capable of achieving better estimation precision as long as the unknown inputs are continuous. Finally, a servo-drive flexible robot arm is selected as an example to demonstrate the applications of the robust observer designs. Full article

(This article belongs to the Special Issue Selected Papers from the 2016 International Conference on Inventions)

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2859 KiB

Open AccessArticle

PSO-Based Voltage Control Strategy for Loadability Enhancement in Smart Power Grids

by Heng-Yi Su, Yu-Liang Hsu and Yi-Chung Chen

Appl. Sci. 2016, 6(12), 449; https://doi.org/10.3390/app6120449 - 20 Dec 2016

Cited by 7 | Viewed by 4886

Abstract

This paper proposes a new voltage control methodology using the particle swarm optimization (PSO) technique for smart grid loadability enhancement. The goal of this paper is to achieve reliable and efficient voltage profile/stability regulation in power grids. This methodology is based on the [...] Read more.

This paper proposes a new voltage control methodology using the particle swarm optimization (PSO) technique for smart grid loadability enhancement. The goal of this paper is to achieve reliable and efficient voltage profile/stability regulation in power grids. This methodology is based on the decouple power flow equations and the worst-case design technique. Specifically, the secondary voltage control (SVC) problem is formulated as an L-infinity norm minimization problem which considers overall load voltage deviations in electrical power systems as an objective model, and the PSO technique is employed to determine a robust control action which aims to improve voltage profile and to enlarge transmission grid loadability by optimal coordinated control of VAR sources. The methodology was successfully tested on several IEEE benchmark systems. Full article

(This article belongs to the Special Issue Selected Papers from the 2016 International Conference on Inventions)

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10210 KiB

Open AccessArticle

The Machining of Hard Mold Steel by Ultrasonic Assisted End Milling

by Ming Yi Tsai, Chia Tai Chang and Jihng Kuo Ho

Appl. Sci. 2016, 6(11), 373; https://doi.org/10.3390/app6110373 - 21 Nov 2016

Cited by 20 | Viewed by 7798

Abstract

This study describes the use of ultrasonic-assisted end milling to improve the quality of the machined surface of hard Stavax (modified AISI 420) mold steel and to reduce the amount of work involved in the final polishing process. The effects of input voltage, [...] Read more.

This study describes the use of ultrasonic-assisted end milling to improve the quality of the machined surface of hard Stavax (modified AISI 420) mold steel and to reduce the amount of work involved in the final polishing process. The effects of input voltage, the stretch length and cutter holding force on the amplitude of the ultrasonic vibration used were measured. The effect of ultrasonic frequency (25 and 50 kHz) and amplitude (0, 2.20 and 3.68 μm) as well as the effect of the rake angle (6° and −6°) and the cutter helix angle (25°, 35° and 45°) on tool wear and quality of the workpiece surface finish were also investigated. It was found that the ultrasonic amplitude increased with cutter stretch length and input voltage, as expected. The amplitude remained constant when the cutter holding force exceeded 15 N. The experimental results showed that the ultrasonic amplitude had an optimum value with respect to surface finish. However, large amplitude ultrasonics did not necessarily improve quality. Furthermore, the cutters used for ultrasonic-assisted milling show less wear than those used for normal milling. It was also found that a positive rake angle and cutters with a large helix angle gave a better surface finish. Full article

(This article belongs to the Special Issue Selected Papers from the 2016 International Conference on Inventions)

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