Taiwan Association of Engineering and Technology Innovation: E-Journals
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An Improved Model Predictive Control Method to Drive an Induction Motor Fed by Three-Level Diode-Clamped Indirect Matrix Converter
Get PDFIn this paper, an improved model predictive control method is proposed to drive an induction motor fed by a three-level matrix converter. The main objective of this paper is to present a novel method to increase the switching frequency at a constant sampling time. Also, it is analytically discussed that increasing the switching frequency not only can decrease the motor current ripples, but it can also significantly reduce its torque ripples. Finally, this study demonstrates that reducing the motor current ripple will improve the quality of the supply current. To be the accurate model and validate the motor drive system, a co-simulation method, which is a combination of FLUX and MATLAB software packages, is employed to find the simulation results. The findings indicate that the proposed method diminishes the THD of the supply current up to 26% approximately. Furthermore, increasing the switching frequency results in the torque ripple reduction by up to 10% almost
Personalized Rehabilitation Recognition Model upon ANFIS
Get PDFThis study applied the Adaptive Neuro-Fuzzy Inference System (ANFIS) to design a recognition model of personalized rehabilitation. In the model, the user may take a wearable sensor and follow the assigned joint-relax exercise to measure the motions of the upper limbs. The sensor that is embedded with the chips of accelerometer, gyroscope, and inclinometer produced the sample datasets due to the exercise schedule of physiotherapy assignment. All motion samples were labeled by arbitrary numbers, which can be identified to the specific motion, for the data training process. A Fuzzy Inference System (FIS) was initially designed by the steps of data pre-processing, featuring, fuzzifying, and ruling Fuzzy logics according to the sample datasets. The FIS was then trained by the ANFIS for optimization by tuning parameters of the features. In testing, the accomplished FIS could recognize the motion features by the defuzzifier that infers the label corresponding to the motion. As a result, the average recognition rate was higher than 90% when the testing motions followed the sampling schedule of the physiotherapy assignment. The model can be applied in the ubiquitous healthcare measurement for health services. The professionals can assess whether the subject obeyed the assigned program or not based on detail motions of the exercise. This approach can be enabled on the trackable interface for the physiatrists to screen the motions of routine rehabilitation
Dynamic Modeling of a Spatial Cable-Driven Continuum Robot Using Euler-Lagrange Method
Get PDFContinuum robots are kinematically redundant and their dynamic models are highly nonlinear. This study aims to overcome this difficulty by presenting a more practical dynamic model of a certain class of continuum robots called cable-driven continuum robot (CDCR). Firstly, the structural design of a CDCR with two rotational degrees of freedom (DOF) is introduced. Then, the kinematic models are derived according to the constant curvature assumption. Considering the complexity of the kinetic energy expression, it has been approximated by the well-known Taylor expansions. This case corresponds to weak bending angles within the specified bending angle range of the robot. On the other hand, due to the low weight of the CDCR components, the gravitational energy effects can be neglected compared to those stemmed from the elastic energy. Thereafter, the corresponding dynamic model is established using Euler-Lagrange method. Static and dynamic models have been illustrated by examples. This analysis and dynamic model development have been compared with the existing scientific literature. The obtained results shown that the consistency and the efficiency of accuracy for real-time have been carried out. However, the dynamic modeling of CDCR with more than 2-DOF leads to a more complex mathematical expression, and cannot be simplified by adopting the similar assumptions and methodology used in the case of 2-DOF
A Circuit-Level Implementation of Voltage-Tuning Scheme for Realizing Optical PAM-4 Using Three-Segment Microring Modulator
Get PDFSilicon Photonics, as one of the solutions to satisfy ever-increasing data bandwidth growth, becomes more challenging due to the latest technologies such as Internet of Things (IoT). Higher order pulse amplitude modulation (PAM) schemes is one of the answers to push towards higher data transmission in the presence of bandwidth limited optical devices. In this paper, we have implemented a circuit-level PAM-4 transmitter design based on the voltage-tuning scheme for realizing optical PAM-4 using a three-segment microring modulator. Simulation results based on the extracted layout using TSMC 65nm LP technology and IMEC-ePIXfab SiPhotonics ISIPP50G technology show that our proposed circuit-level transmitter structure is able to achieve PAM-4 data rate of 25-Gb/s with extinction ratio of 9dB and PAM-4 energy efficiency of 0.5pJ/bit. The results also verify that the scheme is able to achieve high tuning flexibility, but the proposed transmitter will consume more power as a result
Side Resistance of Drilled Shafts Socketed into Rocks for Serviceability and Ultimate Limit States
Get PDFThis study evaluates the analysis models of side resistance in rock sections by utilizing a wide variety of load test data. Available analytical models including the empirical adhesion factor versus the rock’s uniaxial compressive strength and its root are analyzed and compared statistically to determine the optimum relationships. The interpretation criteria for the L1 and L2 methods are used to analyze the load test results for serviceability and ultimate limit states, respectively. The analysis results show that the relationship model with the empirical adhesion factor versus the root of the rock’s uniaxial compressive strength exhibits better correlation than the one with the rock’s uniaxial compressive strength. Moreover, the general coordinate axes regression equation demonstrates better reliability than the semi-logarithmic and full logarithmic axes equations for both limit states. Based on these analyses, specific design recommendations for the side resistance of drilled shafts socketed into rocks are developed and provided with the appropriate statistics to verify their reliability
Design and Optimization of Micro-Machined Sierpinski Carpet Fractal Antenna Using Ant Lion Optimization
Get PDFThis study investigates the optimized Sierpinski carpet fractal patch antenna and also explores the possibility of the integration of the proposed design with monolithic microwave integrated circuits. The optimization process has been performed using an ant lion optimization algorithm to achieve the required operating frequency and impedance matching. Further, due to surface waves excitation in the high index substrates used for the antenna design, the performance of the antenna degrades. Therefore, a process of micro-machining has been adopted to overcome this limitation. The micro-machining process creates an air cavity underneath the patch which further creates the low index environment in the patch antenna causing drastic improvement in the performance parameters along with the compatibility with monolithic microwave integrated circuits. The design shows multiple resonance frequencies in X-band and Ku-band. The proposed micro-machined design shows the resonance at 7.9 GHz, 9.6 GHz, 13.6 GHz, and 19 GHz with a maximum gain of 6 dBi. 
The Design and Prototype Manufacture of a Planetary Gear Reducer
Get PDFThe gear reducer of the power system can be ordinary spur gear reducer, worm and worm gear reducer, or planetary gear reducer. Due to the compact size, light weight, and multi-degrees of freedom; planetary gear reducers are commonly used in various transmissions. One of its applications is used as the gear reducer for industrial purpose. The reduction ratios of 1-stage planetary gear reducers are limited to 3 ~ 10. This paper focused on the design and prototype manufacture of a 1-stage planetary gear reducer. First, according to the concept of train value equation, the planetary gear reducer with reduction ratio 4 is proposed. Based on the involute theorem, the gear data of the planetary gear reducer are obtained. Finally, based on the results of kinematic design and meshing efficiency analysis, the integrated design of the planetary gear reducer was carried out and the prototype was manufactured to verify the design theorem. The results of this paper can be used as a reference for engineers to design the gear reducers for industrial purpose
Performance Characterization of Surface Quality and Tool Wear of Wet/Dry Drilling on Steels by Using Coated Drill Bits
Get PDFThe creation of holes by the drilling operation is a normal process which we were followed from the earlier days. Especially the drill bits’ usage is an Important consideration among the different drilling operations. Here we considered the coated form of drill bits for the purpose of improving the surface quality and to overcome the tool wear by the particulate deposition over the surface of the specimen. The drilling features are to find out over the specimen EN 8 Alloy steel and mild steel which are experimentally verified. In the view of differentiating the eminence of surface roughness and tool wear an appearance of Alloy steel and mild steel specimens, the wet and dry conditioned drilling operations are performed by the manifestation of coolants. The importance of Pertura and Latuma tool coated drill bits developed by the Physical Vapour Deposition (PVD) method are used for this operation. Based on the drilling conditions whether usage or non-usage of coolants is majorly influenced on surface roughness, and the tool coatings are politely influenced on the surface roughness of each specimen have been found out. Likewise, the tool coatings and the rotational speed influenced more on machining time has been recognized. Tool wear patterns are categorized and compared with the simulation data of drilling in Deform 3D. Effective stress is identified and related to the value of surface coarseness in both conditions of drilling on different steel specimens
0D/2D P-doped ZnxCd1-xS/g-C3N4 Heterojunctions towards Highly Efficient Photocatalytic Hydrogen Evolution
Get PDFSolar-driven water splitting over semiconductor photocatalysts is a promising approach for converting solar energy into renewable and storable chemical energy. CdS, an efficient photocatalyst for hydrogen evolution, suffers from high recombination of photogenerated electron-hole pairs and high photocorrosion in aqueous media, which limit its practical applications. Doping and the formation of heterojunctions are two efficient methods to improve the photocatalytic activities of photocatalysts. Herein, we rationally designed and fabricated P-doped 0D/2D ZnxCd1-xS/g-C3N4 nanocomposites by in-situ immobilizing ZnxCd1-xS onto the surface of g-C3N4 nanosheets in a hydrothermal environment, followed by a phosphorization process. The as-prepared P-doped ZnxCd1-xS/g-C3N4 nanocomposites were systematically characterized by analyzing the phase structure, chemical components, electronic and optical properties and separation of charge carriers. More importantly, these P-doped ZnxCd1-xS/g-C3N4 heterostructures have been proven to be highly efficient visible light responsive photocatalysts for hydrogen evolution, and meanwhile exhibit excellent photo-stability during recycling runs. The sufficient evidence exhibit that the significantly improved photocatalytic performance is mainly attributed to the prolonged lifetime of charge carriers and the improved separation efficiency of photogenerated electron-hole pairs
The Innovative Design of the Massage Mechanisms for Massage Chair
Get PDFThis study focuses on the innovative design of massage-mechanisms for massage chair. In this paper, we synthesize the massage-mechanisms based on the modified Yan’s creative design methodology. First, we analyze the topological structure and motion characteristics of existing massage mechanisms and conclude its design requirements and constraints. All existing massage mechanisms with beating and kneading functions are mechanisms with 2 degrees of freedom (DOF). The purpose of this paper is to synthesize all the feasible designs of massage mechanisms (including F=2 and F=3). For the mechanisms with 3 DOF, they must have 1 redundant degree of freedom. Then, based on the design requirements and constraints and modified Yan’s creative design methodology, we synthesize 14 design concepts of massage-mechanisms for massage chair. One of the design concepts will be completed the practice including kinematic design, engineering drawing, and the prototype manufacture. As the results, we conclude that the new design has only 5 links (less than existing design) and same kneading and beating traces, and is better than existing design