bluuebunny/crossref_metadata_2025 huggingface dataset:
EFFECT OF SERVO SYSTEMS ON THE CONTOURING ERRORS IN INDUSTRIAL ROBOTS
Authors: Slamani Mohamed , Nubiola Albert , Bonev Ilian A.
Published: April 2018

Two important aspects of the performance of a servo system, tracking errors and contour errors, significantly affect the accuracy of industrial robots under high-speed motion. Careful tuning of the control parameters in a servo system is essential, if the risk of severe structural vibration and a large contouring error is to be avoided. In this paper, we present an overview of a method to diagnose contouring errors caused by the servo control system of an ABB IRB 1600 industrial robot by measuring the robot’s motion accuracy in a Cartesian circular shape using a double ballbar (DBB) measurement instrument. Tests were carried out at different TCP (tool centre-point) speed and trajectory radii to investigate the main sources of errors that affect circular contouring accuracy. Results show that radius size errors and out-of-roundness are significant. A simple experimental model based on statistical tests was also developed to represent and predict the radius size error. The model was evaluated by comparing its prediction capability in several experiments. An excellent error prediction capability was observed.
DIRECT ADAPTIVE FUZZY SLIDING OBSERVATION AND CONTROL
Authors: Gholami Alireza , Markazi Amir H.D.
Published: April 2018

In this paper, a new direct adaptive fuzzy sliding observation and control (AFSOC) method is proposed. The method can be applied to a class of unknown nonlinear systems. The proposed observer estimates the closed-loop state tracking error asymptotically, provided that the output gain matrix includes Hurwitz coefficients. The chattering phenomenon is overcome by using a boundary layer around the sliding surface. The stability of the AFSOC method is proved using the Lyapunov stability theory. Numerical simulation on a benchmark chaotic system depicts the effectiveness of the proposed algorithm.
HEAT TRANSFER FROM TWO DISCRETE FLUSH-MOUNTED HEATERS SUBJECTED TO LAMINAR PULSATING AIR FLOW IN A CHANNEL
Authors: Akdag Unal
Published: April 2018

In this article, a numerical study on heat transfer in laminar pulsating air flow in a channel around two discrete flush-mounted heat sources is reported. Simulations are conducted for five different frequencies and three different amplitudes while the Reynolds number (Re = 125) and Prandtl number (Pr = 0.71) remain constant for all cases. In addition, limited geometric parameters such as spacing between the two discrete heaters are investigated. Numerical simulations are performed by using the commercial CFD code Fluent. The optimum heat transfer parameters are analyzed. The time-mean Nusselt number is obtained for a cycle and given as dimensionless parameters. The heat transfer enhancements are found for low frequencies and high amplitudes.
NUMERICAL INVESTIGATION OF THE EFFECT OF INLET GASES HUMIDITY ON POLYMER EXCHANGE MEMBRANE FUEL CELL (PEMFC) PERFORMANCE.
Authors: Ahmadi Nima , Rezazadeh Sajad , Yekani Mirkazem , Fakouri Alireza , Mirzaee Iraj
Published: April 2018

A full three-dimensional, single phase model of a proton exchange membrane fuel cell (PEMFC) has been developed. A single set of conservation equations developed and numerically solved using a finite volume based computational fluid dynamics technique. In present investigation some parameters such as transport phenomena, fuel cell performance for conventional model (base case) and the effect of inlet gases humidity on cell performance were investigated in more details. The numerical results prove that the inlet gases humidity and membrane water management are most important parameters that affect cell performance and transport phenomena in fuel cell. Finally the numerical results are compared with experimental data, which represent good agreement.
ELECTROMECHANICAL CHARACTERISTICS OF POLYVINYLIDENE FLUORIDE FOR FLEXIBLE ELECTRONICS
Authors: Chang Wen-Yang , Hsu Cheng-Hung
Published: April 2018

The electromechanical characteristics of PVDF are investigated, including the crystallization, frequency responses, hysteresis, leakage currents, current-voltage characteristics, and fatigue characteristics using X-ray diffraction and an electrometer. Results show that the frequency band of PVDF increases with increasing resistive load and capacitance. The hysteresis area of ΔH slightly increases with increasing input voltage. The magnitude of the current values increases with decreasing delay time at a given drive voltage. PVDF film induced larger degradation when the number of stress cycles was increased to about 105 cumulative cycles.
AN EXPERIMENTAL STUDY ON THE CONNECTION OF CROSSBEAMS IN A MODULAR BRIDGE
Authors: Cho Dooyong , Kim WooSeok , Park Sunkyu
Published: April 2018

A recently the application of modular bridge system, an assembly of the structural members, has been required to minimize traffic congestion, to reduce the period of construction, and to improve the quality and workability during the new construction and reconstruction of the bridge. For this reason, the modular bridge system is necessary to prepare for near future. In this study, alternative crossbeam system for modular prestressed concrete (PSC) T-girder bridge was developed. Static loading test was performed to inspect the structural characteristics of the alternative crossbeam system. Experimental results were analyzed and compared with each data. Therefore, the appropriate crossbeam system for modular PSC T-girder bridge was proposed.
ROBUST FINITE TIME CONTROLLER DESIGN FOR SECOND ORDER NONLINEAR UNDERACTUATED MECHANICAL SYSTEMS
Authors: Cheng Chi-Cheng , Yang Kuang-Shine , Yang Jung-Hua
Published: April 2018

For a class of second order underactuated mechanical systems, a robust finite time control strategy is developed in this paper. The robust finite time controller is to drive the tracking error to be zero at the fixed final time. In order to assure system stability, we present a generalized Lyapunov stability proof for the second order underactuated mechanical system. By utilizing a Lyapunov stability theorem, we can achieve finite time tracking of desired reference signals for underactuated systems, which are subject to both external disturbances and system uncertainties. The proposed control scheme is demonstrated by actual experiments on a Furuta pendulum system.
A NOVEL DESIGN OF SEMI-ACTIVE SUSPENSION SYSTEM USING MAGNETO RHEOLOGICAL DAMPER ON LIGHT-WEIGHT VEHICLE
Authors: Shiao Yaojung , Nguyen Quang-Anh , Lai Chun-Chi
Published: April 2018

This paper focuses on the analysis and control of a semi-active suspension for light-weight vehicles with small compact car body. The suspension was chosen due to its small system space, low complexity and easy maintenance. A new magneto rheological damper was designed and validated by computer simulation. After that, models of a quarter-car suspension with air spring and the new damper were built. Due to the nonlinear dynamic phenomena of system components, a self-tuning fuzzy logic controller was developed. Simulation results showed that the designed suspension system with its controller had good performance in vibration suppression on various operation conditions.
A NEW ELECTROMAGNETIC VALVE TRAIN WITH PM/EM ACTUATOR IN SI ENGINES
Authors: Shiao Yaojung , Dat Ly Vinh
Published: April 2018

This paper proposes a new electromagnetic valve train (EMV), which uses hybrid permanent magnet and electromagnetic coil (PM/EM). The new EMV is characterized by a special structure, simple actuator as well as optimal parameter designs. This EMV brings many benefits, such as valve dynamic, actuator control, and low operation energy consumption, etc. The simulation results show that this EMV achieves a 15% volume reduction and a 20% enhancement in holding force by special armature design. Additionally, the estimated energy consumption of EMV operation for the proposed EMV indicates that this EMV has the lowest operating energy compared with other EMVs.
HYDROSTATIC MECHANISM OF A WAVY-TILT-DAM MECHANICAL SEAL
Authors: Liu Wei , Liu Ying , Zhai Jingjing , Huang Weifeng , Wang Yuming
Published: April 2018

A theoretical model is developed to study the hydrostatic mechanism of the WTD seal in this paper. The influences of structure parameters on the seal performance are studied under different rotor speed and sealed pressure. The results show that the existence of waves will impair the hydrostatic effect in the radial direction and promote the hydrostatic effect in the circumferential direction. The taper β1 will dominate the performance of the WTD seal under the stable working condition when there is no cavitation occurs.
STUDY OF A NEW AND LOW-COST MEASUREMENT METHOD OF VOLUMETRIC ERRORS FOR CNC FIVE-AXIS MACHINE TOOLS
Authors: Wang Shih-Ming , Yu Han-Jen , Liao Hung-Wei
Published: April 2018

An effective and inexpensive volumetric error measurement method is an essential of the software-based error compensation method that can improve the machining accuracy of a CNC machine tool without increasing hardware manufacturing cost. In this paper, a new volumetric-error measurement method incorporating of three derived error models, two-step measurement procedure, and use of telescoping ball-bar was proposed for three major types of five-axis machine tools. Comparing to the methods currently used in industry, the proposed method provides the advantages of low cost, easy setup, and high efficiency. The simulation and experimental results have shown the feasibility and effectiveness of the method.
EXPERIMENTAL STUDY OF FREE CONVECTION HEAT TRANSFER IN THE POROUS METAL-FOAM HEAT SINK
Authors: Jeng Tzer-Ming , Tzeng Sheng-Chung , Yeh Zhi-Ting
Published: April 2018

This study experimentally investigated the free convection heat transfer characteristics of the annular metal-foam heat sinks. The results showed that the heat transfer coefficient (h) decreased as the pore density of metal foams increased when the thickness (tc) of the annular metal foams equaled 5 mm, but the (h) increased as the pore density increased when tc = 11 and 14.5 mm. Besides, the (h) increased firstly and then decreased as (tc) increased. There was better heat transfer effect when tc = 11 mm in the present study.
ATOMISTIC SCALE SIMULATION OF TEXTURED SURFACES ON DRY SLIDING FRICTION
Authors: Chen Ming-Yuan , Hong Zheng-Han , Fang Te-Hua , Kang Shao-Hui , Kuo Li-Min
Published: April 2018

Fe sliding on a Fe substrate with surface texturing is investigated using molecular dynamics simulation. The modified embedded-atom method many-body potential is used to describe the interaction of Fe atoms. The tribological properties of surface texturing during nanosliding are discussed. Results indicate that a textured surface has lower friction than that of a flat surface. In addition, a surface with parallel grooves has lower friction than that of a dimpled surface. Hence, surface texturing greatly affects friction.
EXPERIMENTAL INVESTIGATIONS OF MPPT IN A SMALL SCALE PHOTOVOLTAIC ENERGY SYSTEM BASED ON EXTREMUM SEEKING CONTROL
Authors: Yau Her-Terng , Wu Chen-Han
Published: April 2018

This study carried out experimental validation based on the simulation analysis results of Yau and Wu [1], and compared the MPPT situations of three kinds of extremum seeking control. It was proved that the sliding mode extremum seeking control has better transient response and steady-state characteristic, and changes the sunshine intensity to test the performance of algorithm, thus proving that the system can track the maximum power point rapidly in the environment with rapid atmospheric changes.
USING ADAMS FOR MECHANISM SIMULATION APPLICATION OF MULTIAXIS MACHINES
Authors: Lee Yi-Ming , Hsu Kuei-Shu , Chang Shyue-Bin
Published: April 2018

The aim of this paper is to implement the efficiency of the new model multi-axis CNC machine by using a visual solid mechanism simulation methodology design. The advantage of this simulation design is to activate each running procedure simultaneously when a transient motion occurs in the mechanism system. Using the simplified elements of a conceptual dynamic mechanism simulated by ADAMS we will demonstrate the feasibility in design through kinematics analysis of the new five axis CNC model.
INTELLIGENT PASSIVE CONTROL FOR LOWER LIMB REHABILITATION SYSTEM
Authors: Hsieh Ming-Shium , Chen Chin-Sheng , Chien Kuan-Sheng
Published: April 2018

This paper proposes the design and control of continuous passive motion (CPM) machine based on constraint-induced movement therapy (CIMT). First, the dynamic model of the CPM machine is derived for further controller design by the principal of virtual work. Then, an intelligent sliding-mode control (ISMC) system which involved recurrent Hermite neural network (RHNN) estimator to estimate the unknown external disturbance and uncertainty is proposed to track the angular position and velocity of the CPM machine.
NUMERICAL SIMULATION OF MIXED CONVECTION WITHIN NANOFLUID-FILLED CAVITIES WITH TWO ADJACENT MOVING WALLS
Authors: Esfe Mohammad Hemmat , Ghadi Ariyan Zare , Noroozi Mohammad Javad
Published: April 2018

In this study, nanofluid flow and heat transfer in a cavity with two moving lids are investigated. Governing equations are solved by finite volume approach using SIMPLE algorithm over a staggered gird system. The results show that when the moving lids have opposing effect, the streamlines contain two main vortices. By increasing the Richardson number, intensity of the vortex complying with buoyancy force increases, while intensity of the other vortex decreases. When the moving lids have aiding effect, the streamlines contain one the primary dominant vortex in which its strength increases with increase of the buoyancy force. In this case, rate of heat transfer is more than other cases.
EFFECTS OF IMPACT LOCATION AND ANGLE OF A FLYING CROSS BAR ON THE PROTECTION OF A LONG-ROD PENETRATOR
Authors: Yoo Yo-Han , Paik Seung Hoon , Kim Jong-Bong , Shin Hyunho
Published: April 2018

Based on a finite element analysis, the performance of a flying cross bar in protecting a long-rod penetrator increases as the impact location moves toward the head of the penetrator. It also increases as the impact angle approaches right angle. The optimal impact location along the span direction of the bar varies depending on the bar diameter.
EFFECT OF AMBIENT TEMPERATURE ON THE PERFORMANCE OF A COMBINED CYCLE POWER PLANT
Authors: Tiwari Arvind Kumar , Hasan Mohd. Muzaffarul , Islam Mohd.
Published: April 2018

The aim of the present paper is to examine the effect of ambient temperature on the performance of a combined cycle power plant. For this work, the combined cycle plant chosen is NTPC (National Thermal Power Corporation) Dadri, India where a gas unit of 817 MW is installed. The effect of ambient temperature on combined cycle efficiency, gas turbine cycle efficiency, exergy destruction in different components, exergy loss via exhaust and air fuel ratio at lower and higher turbine inlet temperature are reported. The results show that the net decrease in combined cycle efficiency is 0.04% and the variation in exergy destruction of different plant components is up to 0.35% for every °C rise in ambient temperature.
EFFECT OF INTERNAL POWER-ANGLE ON TURBO-GENERATOR ROTOR VIBRATION CHARACTERISTICS UNDER ECCENTRICITY FAULTS
Authors: Wan Shuting , He Yuling , Zhan Changgeng
Published: April 2018

This paper investigates the effect of the turbo-generator internal power-angle on the rotor radial vibration characteristics under air gap eccentricity faults. Firstly the air gap magnetomotive force, the magnetic permeance and the magnetic flux density of the eccentricity faults is deduced, and the formula of the magnetic pull per unit area is obtained. Then the restrictive factors of the magnetomotive force and the internal powerangle are analyzed. The unbalanced magnetic pull (UMP) that acts on the rotor is further deduced, and the rotor vibration characteristics are given. Finally the experiments are taken on a SDF-9 non-salient fault simulating generator to verify the theoretical results. The investigation results of this paper will be beneficial to air gap eccentricity faults diagnosis of turbo-generator.
A NUMERICAL AND EXPERIMENTAL INVESTIGATION OF COALESCENCE BETWEEN CYLINDRICAL HOLES
Authors: Griffin Joel S. , Butcher Clifford J. , Chen Zengtao
Published: April 2018

A sequential digital image technique was employed to detect the onset of coalescence between pairs of holes in tensile specimens. The coalescence event was induced between cylindrical holes that were positioned with various spacing and ligament orientations. Using finite-element analysis as a framework, the coalescence predictions of a classic micromechanical model were compared with the experimental coalescence results. It was found that the predicted strains at coalescence could be significantly improved by accounting for local work-hardening in the ligament region between the two holes. Digital image correlation was used to extract strain values from the digital image record, for both the far-field and the intervoid ligament.
DYNAMICS OF A SORTING PROCESS WITH A STREAM OF DISCRETE IMPACT LOADS
Authors: Piatkowski Tomasz , Sempruch Janusz , Tomaszewski Tomasz
Published: April 2018

The sorting process applied to a stream of unit loads (cubiform objects, parcels) transported on conveyors is investigated. The sorting process is performed by means of an active fence (flexible arm) that makes a 1dof rotary motion. The manipulated loads are treated as bodies with nonlinear elastic-damping properties described by modified nonlinear Kelvin model. The equations of motion of the flexible fence, and those of the interacting object, are derived using the finite element method. The assessment of influence of constructional and operating parameters of the fence on the course of the sorting process and dynamic forces exerted on the loads handled is studied.
DETERMINATION OF THE ELEMENTS OF PRODUCTION CYCLE TIME IN SERIAL PRODUCTION: THE SERBIAN CASE
Authors: Ćoćkalo Dragan , Stanisavljev Sanja , Đorđević Dejan , Klarin Milivoj , Brkić Aleksandar Đ.
Published: April 2018

A model for the stochastic determination of the elements of production cycle time is proposed and experimentally verified in this survey. The originality of the model as reflected in the idea of using a work sampling model to monitor the production cycle is one of the most significant indicators of production effectiveness and efficiency, instead of applying classical methods. It has been experimentally proved that for a corresponding representative set the elements of working time range according to normal distribution law and that, dynamically viewed, it is possible to use mean value calculations to establish control limits on three standard deviations for the individual elements of working time and thus to master the process. Based on our experimental investigations, it has been proved that in the practice of small and medium-sized enterprises with serial production it is possible to design and apply a very simple but accurate enough stochastic model to determine the elements of working cycle time and in this way optimize the duration of production cycle time.
RELATIVE IMPORTANCE OF FUEL PROPERTIES ON GDI FUEL SPRAY TIP PENETRATION
Authors: Bruyère-Bergeron Simon , Seers Patrice
Published: April 2018

Experiments were conducted to propose correlations of fuel spray tip penetration of a direct-injection injector fed with ethanol, butanol, isooctane, gasoline, and associated blends at different injection and ambient pressures. Correlations are proposed that enable predicting spray tip penetration as a function of fuel properties. The main findings are that alcohols offer less penetration than isooctane and gasoline, which have similar behaviour at 295 K. Ambient density played a major role in spray tip penetration, while the boiling temperature and enthalpy of vaporization were important fuel properties under warmer conditions.
MESH CONVERGENCE STUDY FOR 2-D STRAIGHT-BLADE VERTICAL AXIS WIND TURBINE SIMULATIONS AND ESTIMATION FOR 3-D SIMULATIONS
Authors: Zadeh Saman Naghib , Komeili Matin , Paraschivoiu Marius
Published: April 2018

Mesh resolution requirements are investigated for 2-D and 3-D simulations of the complex flow around a straight-blade vertical axis wind turbine (VAWT). The resulting flow, which may include large separation flows over the blades, dynamic stall, and wake-blade interaction, is simulated by an Unsteady Reynolds-Averaged Navier–Stokes analysis, based on the Spalart-Allmaras (S–A) turbulence model. A grid resolution study is conducted on 2-D grids to examine the convergence of the CFD model. Hence, an averaged-grid residual of y+ > 30 is employed, along with a wall treatment, to capture the near-wall region’s flow structures. Furthermore a 3-D simulation on a coarse grid of the VAWT model is performed in order to explore the influence of the 3-D effects on the aerodynamic performance of the turbine. Finally, based on the 2-D grid convergence study and the 3-D results, the required computational time and mesh to simulate 3-D VAWT accurately is proposed.
DESIGN AND ANALYSIS OF GENEVA MECHANISM WITH CURVED SLOTS
Authors: Hsieh Jung-Fa
Published: April 2018

A simple yet comprehensive method is proposed for the design of a Geneva indexing mechanism with curved slots. In the proposed approach, conjugate surface theory is used to derive an analytical description of the profile of the curved slots with and without an offset feature. Analytical formulae are then presented for the pressure angle of the Geneva mechanism and the principal curvatures of the curved slots. The effectiveness of an appropriate offset angle in eliminating the singular points and double-points on the curved slot profile is then demonstrated. Finally, a Geneva mechanism is fabricated in order to demonstrate the feasibility of the proposed approach.
EFFECTS OF SLIP ON THE VON KÁRMÁN SWIRLING FLOW AND HEAT TRANSFER IN A POROUS MEDIUM
Authors: Sahoo Bikash , Poncet Sébastien , Labropulu Fotini
Published: April 2018

Numerical solutions are obtained for the fully coupled and highly nonlinear system of differential equations, arising due to the steady Kármán flow and heat transfer of a viscous fluid in a porous medium. The conventional no-slip boundary conditions are replaced by partial slip boundary conditions owing to the roughness of the disk surface. Combined effects of the slip λ and porosity γ parameters on the momentum and thermal boundary layers are studied in detail. Both parameters produce the same effects on the mean velocity profiles, such that all velocity components are reduced by increasing either λ or γ. The temperature slip factor β has a dominating influence on the temperature profiles by decreasing the fluid temperature in the whole domain. The porosity parameter strongly decreases the heat transfer coefficient at the wall for low values of β and tends to an asymptotical limit around 0.1 for β ≃ 10. The porosity parameter γ increases the moment coefficient at the disk surface, which is found to monotonically decrease with λ.
FAULT DIAGNOSIS BASED ON LMD-SVD AND INFORMATION-GEOMETRIC SUPPORT VECTOR MACHINE FOR HYDRAULIC PUMPS
Authors: Tian Ye , Lu Chen , Wang Zhipeng , Wang Zili
Published: April 2018

This study proposes a fault diagnosis method for hydraulic pumps based on local mean decomposition (LMD), singular value decomposition (SVD), and information-geometric support vector machine (IG-SVM). First, the nonlinear and non-stationary vibration signals are decomposed using LMD into several product functions (PFs). Then, the PFs are processed by SVD to obtain more stable and compact feature vectors. Finally, the health states are identified by an IG-SVM classifier, which is less-dependent on the selected kernel function and parameters than SVM. In addition, the comparisons between LMD, EMD, and WPD demonstrate the superiority of LMD in feature extraction. Compared with SVM and BP neural network, IG-SVM shows higher classification accuracy and computational efficiency in dealing with small-sample fault diagnosis. From the experimental results, it was concluded that the proposed method can effectively realize fault diagnosis for hydraulic pumps under small-sample conditions.
REAL-TIME RELIABILITY ASSESSMENT AND LIFETIME PREDICTION FOR BEARINGS USING THE INDIVIDUAL STATE DEVIATION BASED ON THE MANIFOLD DISTANCE
Authors: Gan Zu-wang , Ma Jian , Lu Chen , Liu Hongmei , Shan Tian-min
Published: April 2018

In recent years, the real-time reliability evaluation and life prediction for rolling bearings has attracted more attention. Most of the existing methods employ real-time transformation of traditional reliability indices, performance degradation trajectory or distribution analysis, which usually have certain limitations in terms of accuracy and applicability. This paper proposes a method for bearing real-time reliability evaluation and life prediction to avoid the negligence of real-time transformation of the monitored individual, as well as reduce the errors caused by the randomness from individual bearing operational process. The individual state deviation of a running rolling bearing geometrically measured by manifold distance is normalized into a state deviation degree, which is used to formulate a modified real-time reliability model for realtime reliability evaluation and lifetime prediction. Finally, the feasibility and efficiency of this method is validated by bearing run-to-failure experiments.
ON-LINE PERFORMANCE ASSESSMENT AND FAULT DIAGNOSIS OF MECHANICAL SYSTEMS
Authors: Chen Shang-Liang , Cheng Yin-Ting , Liu Hsien-Cheng , Chen Yun-Yao
Published: April 2018

This study integrates sensors, signal capture equipment, industrial computers and machinery health check-up software to develop an On-line Performance Assessment and Fault Diagnosis of Mechanical System, helping engineers predict mechanical conditions. Physical quantities captured by the sensors is utilized to process physical signals, and the Wavelet Packet Energy method is used for the feature extraction of non-stationary signals in coordination with the Principal Component Analysis for feature selection. This study establishes On-line Performance Assessment and Fault Diagnosis of Mechanical System based on Discriminant Analysis which is able to immediately determine the mechanical performance. When abnormal mechanical conditions occur, Bayesian Network will be activated to construct error diagnostic model and determine possible causes of error or malfunction of the machinery. Finally, the system is applied to the fan motor, high-speed spindle motor and AC motor of the machine tool. Experimental results show that the theory can effectively diagnose mechanical performance remarkable with an accuracy rate of 92.50% or higher.
DEFECT IMPROVEMENT OF EXTRUSION DIES USING COMBINATION OF FEM STRESS ANALYSIS WITH THE TAGUCHI METHOD
Authors: Chang Kao-Hua , Shih Ching-Wei , Tzou Gow-Yi
Published: April 2018

This study aims at analyzing the influence of the maximum principal stress on Tungsten Carbide Steel die core in an extrusion die which caused the crack of die core, and then adjusts the dies assembly method in order to improve the service life of die. In this study, we combine FEM simulation software with the Taguchi Method L9(34) to choose the cobalt content for die core materials, and the quantity of shrink fit while assembling the die core and die case as the reference parameters. When carrying out the simulation process, we compared the changes of the maximum principal stress of the die core caused by the plastic deformation of die materials to achieve the minimum expected value as the goal for the most optimal die combination. Then, the results obtained are to make dies in trial and mass-production practically; as a result, the die life is improved from the original 1000 to 150,000 pcs, which is more than 150 times better than before.
ON THE NEW MECHANICAL PRESS WITH A PLANETARY GEAR TRAIN
Authors: Soong Ren-Chung
Published: April 2018

A new 1-DOF mechanical press with a geared eight-bar linkage mechanism is presented. The proposed press can generate the required kinematic and dynamic performance for drawing, stamping, deep drawing, and precision cutting processes by simply adjusting the offset of the ram. The press consists of an elementary planetary gear train with a pair of planet gears, a slider-crank mechanism, and a slider-crank mechanism with a variable-length crank. The configuration and a solid model are described, and a kinematic analysis, dynamic analysis, and optimized dimensional synthesis of the press are discussed. Examples are provided to verify the feasibility and effectiveness of the design methodology. The proposed press could lead to more flexible and cost-effective applications.
PARAMETRIC TRAJECTORY OPTIMISATION FOR INCREASED PAYLOAD
Authors: Gallant André , Gosselin Clément
Published: April 2018

The load-carrying capacity of manipulators is often considered to be the same throughout their workspace. However, the actual capacity of manipulators largely depends on their posture, their velocity, their acceleration and the limits of their actuators. In this paper, a method is proposed to increase the payload capacity of manipulators through trajectory optimisation. This optimisation is performed on a task basis and therefore, the load-carrying capacity varies from task to task. An extensive analysis of the method is conducted based on its application on a planar RR serial two degree-of-freedom manipulator. This analysis evaluates the ability of the method to find feasible trajectories and compares the results with those obtained using Bang-bang type methods. It is shown that, although the trajectories produced by the proposed method are not time optimal, the method is much more versatile and much simpler to implement than its Bang-bang counterparts.
A SOLUTION FOR NONLINEAR STABILITY ANALYSIS OF QFT CONTROLLERS DESIGNED FOR HYDRAULICALLY ACTUATED SYSTEMS
Authors: Esfandiari Masoumeh , Sepehri Nariman
Published: April 2018

Quantitative feedback theory (QFT) is a well-established technique to design robust and linear controllers. However, the important open problem of extending the small signal stability to nonlinear stability verification has remained an ongoing research in the design of QFT controllers. In this paper, we show that Takagi–Sugeno (T–S) fuzzy modeling approach and its stability theory provide a new opportunity to study the nonlinear stability of QFT controllers in fluid power systems. To validate the approach, two case studies are provided first. The first case study establishes the reliability of the approach by confirming the results for a hydraulic system of which nonlinear stability has already been proven. The second case study establishes that using the proposed approach, we can further study and extend the stability region of previously developed hydraulic controllers to include parametric uncertainty. Followed by the successful validation of the effectiveness of our approach through these two case studies, the stability of a QFT position controller, for which the nonlinear stability was never proven, is investigated.
DRY SLIDING WEAR BEHAVIOR OPTIMIZATION OF STIR CAST LM6/ZrO2 COMPOSITES BY RESPONSE SURFACE METHODOLOGY ANALYSIS
Authors: Karthikeyan G. , Jinu G.R.
Published: April 2018

LM6 was reinforced with various percentages of ZrO2 particles by using stir casting method. The prepared samples were subjected to tensile and wear test at variable loads by using a pin-on-disc wear tester. The curve fitting technique was used to develop the respective linear, logarithmic, polynomial, power law equations. The wear worn surface and surface roughness of the specimen were studied. Response Surface Methodology (RSM) was used to minimize the number of experimental conditions and develop the mathematical model between the key process parameters namely weight percentage of ZrO2, load and sliding distance. Analysis of Variance technique was applied to check the validity of the developed model. The mathematical model developed for the specific wear rate was predicted at 99% confidence level and some useful conclusions were made.
NONLINEAR DYNAMIC CHARACTERISTICS OF MAGNETIC SHAPE MEMORY ALLOY ACTUATOR
Authors: Zhu Zhi-Wen , Li Xin-Miao , Xu Jia
Published: April 2018

A kind of hysteretic nonlinear model of magnetic shape memory alloy (MSMA) is developed in this paper, and the nonlinear dynamic characteristics of a MSMA actuator are studied. Nonlinear differential items are introduced to explain the hysteretic phenomena of MSMA, and the magneto-mechanical coupled model of MSMA actuator in harmonic magnetic fields is developed. The relationship between input magnetic signal and output displacement is obtained, and the phenomena of the MSMA actuator’s accuracy aggravation in high-frequency magnetic field are explained. The theoretical and experimental results show that there are multiple frequencies in the response of the system, and the system’s motions change from periodic orbits to chaos with the increase in the level of the input magnetic signals; the multi-frequency vibration is induced by the hysteretic nonlinear characteristics of magnetic shape memory alloy.
DYNAMIC BEHAVIOR OF A STEEL PLATE SUBJECTED TO BLAST LOADING
Authors: Park Jong Yil , Jo Eunsun , Kim Min Sook , Lee Seung Jae , Lee Young Hak
Published: April 2018

This paper presents the results of an experimental test conducted on the blast resistance of a steel plate. A supporting steel frame on a concrete foundation was designed for testing a steel plate target against blast loading. A 1220 mm × 2140 mm × 10 mm steel plate was tested and subjected to the explosion of 50 kg of TNT (tri-nitro toluene) at a stand-off distance of 20 m. Data collected from the specimen included the strain and deflection of the steel plate. The test data were analyzed to evaluate the performance of the plate. The test results were compared with the results of Autodyn, which is a finite element method-based commercial software. The analytical results showed minor differences from the test results when the boundary conditions of the steel plate assumed that the upper and lower sides were fixed and the other sides were free.
THE SYSTEMATIC DESIGN OF PLANETARY-TYPE GRINDING DEVICES FOR OPTICAL FIBER FERRULES AND WAFERS
Authors: Hsieh Long-Chang , Chen Tzu-Hsia
Published: April 2018

The traditional planetary grinding device can only polish one optical fiber ferrule. The other grinding device with donut polishing trace is also proposed for polishing wafer. This grinding device has a problem, that is, “the polishing qualities of different points on the wafer are not the same”. Hence, this paper proposes a new planetary grinding device for polishing more optical fiber ferrules and more wafers. Based on the kinematics of planetary gear train, the equations of polishing trace and velocity are derived. Then, the velocity deviation percentage (Vdp) is calculated, which is an important design parameter. Area ratio (AR) is defined as polishing area divided by grinding pad area. The area ratio (AR) is another important design parameter for designing planetary grinding devices. In this paper, two design examples are used to illustrate the design process. The research results of this paper can provide an experience for the systematic design of planetary grinding devices.
A SELF-CALIBRATION METHOD FOR ARTICULATED ARM COORDINATE MEASURING MACHINES
Authors: Gao Guanbin , Na Jing , Wu Xing , Guo Yu
Published: April 2018

To improve the accuracy of articulated arm coordinate measuring machines (AACMM) and simplify the calibration process, an improved self-calibration method was proposed. Unlike the traditional calibration methods, which need external expensive precision instruments and elaborate setups, the proposed self-calibration method only requires a gauge to assist the data acquisition operation. By designing a movement trajectory of the AACMM, a series of joint angles can be obtained to form overdetermined equations based on the kinematic model of the AACMM. Therefore, the structural parameters of the AACMM can be obtained by solving the equations. Consequently, the calibration can be achieved by solving these equations. The coefficient matrix of the equations was further analyzed to simplify the equations, and a constructive method was presented to identify the structural parameters by solving the simplified equations with a modified simulated annealing algorithm, in which an optimized search strategy was applied to improve the robustness and efficiency. Experimental studies on an AACMM validate the convenience and effectiveness of the proposed AACMM self-calibration approach.
SWINGING LEG CONTROL OF A LOWER LIMB EXOSKELETON VIA A SHOE WITH IN-SOLE SENSING
Authors: Zhu Yanhe , Zhang Chao , Fan Jizhuang , Yu Hongying , Zhao Jie
Published: April 2018

A lower limb exoskeleton can help in weight-bearing and walking to assist laborers doing heavy work. For exoskeleton-assisted walking, the wearing comfort and walking convenience are important so there must be minimal interference with leg movement. Hence, a peculiar design strategy based on an in-sole sensing shoe is presented to achieve real-time motion detection and follow-up control of the moving leg. Compared to the elastic muscle extension, the sensor must exhibit minimal deflection under load. Therefore, an ultra-thin structure integrating 6 bar linkages and 3 cantilevers has been used in the design of the in-sole sensing shoe which can detect force in two directions and torque in one. A swing phase experiment and a random leg motion test were carried out. Results show validity of human motion detection and follow-up control strategy based on this plantar surface sensor.
DOCUMENT DELIVERY ROBOT BASED ON IMAGE PROCESSING AND FUZZY CONTROL
Authors: Juang Jih-Gau , Yang Chang-Yen
Published: April 2018

The objective of this study is to integrate image processing, pattern recognition, RFID, and fuzzy theory into an omnidirectional wheeled mobile robot for receiving and delivering documents between rooms. In image pre-processing, the Hue-Saturation-Lightness color space is applied to avoid light interference, and then grayscale image threshold is used to obtain binary image. The median filter is utilized to filter the noises of speckle and salt-and-pepper, so color segmentation is then applied to capture desired color for tracking control. Pattern recognition is performed by the Adaptive Resonance Theory. RFID reader and room tag is used to verify the room number of the destination so that the recognition error from image processing can be avoided. Fuzzy theory is implemented into an omnidirectional wheeled mobile robot control design for driving the wheels of the robot. Experimental results show that the proposed control scheme can make the omnidirectional mobile robot move to destination, receive and deliver documents between offices.
DESIGN OF A FUZZY-PID CONTROLLER FOR A NANOSCALE X-Y PLATFORM
Authors: Zheng Xiuli , Fan Yi-Hua , Chen Ching-En , Lin Ya-Qi , Liao Hung-Wen , Hsieh Sheng-Chung
Published: April 2018

A fuzzy-PID controller design was proposed in this paper for a nanoscale platform positioning system. The target nanoscale X-Y platform is mounted on a pantograph mechanism and restricts the rotation by two small sliders; the device is driven by a traditional X-Y platform with common precision. The goal of this study is to drive the target platform’s movement in the region of 5 mm × 5 mm for the positioning, with repeated positioning accuracy error less than 200 nm by the traditional X-Y platform. Due to the different PID parameters affecting platform positioning accuracy and system response for the two axes, the fuzzy-PID controller will train to fit the mechanism to promote the positioning precision and path control effect. The simulation and experimental results indicated that the proposed method is feasible for nano-scale micro-platform positioning.
SUB-OPTIMAL ALGORITHM SECOND-ORDER SLIDING MODE CONTROL FOR A SYNCHRONOUS RELUCTANCE MOTOR SPEED DRIVE
Authors: Chiang Huann-Keng , Lin Wen-Bin
Published: April 2018

A sub-optimal algorithm second-order sliding mode controller (SOSMC) was presented for a synchronous reluctance motor (SynRM) speed drive. SOSMC is an effective tool for the control of uncertain nonlinear systems since it overcomes the main chattering drawback of conventional sliding mode control. The practical implementation of SOSMC has simple control laws and assures an improvement in sliding accuracy with respect to conventional sliding mode control. This paper proposes a control scheme based on sub-optimal algorithm SOSMC. The proposed SOSMC is robust against motor parameter variations and mitigates chattering phenomenon. Experiments were conducted to validate the proposed method.
BEARING PERFORMANCE DEGRADATION ASSESSMENT BY ORTHOGONAL LOCAL PRESERVING PROJECTION AND CONTINUOUS HIDDEN MARKOV MODEL
Authors: Liu Tao , Wu Xing , Guo Yu , Liu Chang
Published: April 2018

Bearing is the key component in rotating machine. It is important to assess the performance degradation degree of bearings for making proactive maintenance and realizing near-zero downtime. A methodology based on orthogonal local preserving projection (OLPP) and continuous hidden Markov model (CHMM) is introduced in bearing performance degradation assessment. Firstly, the time domain, frequency domain and time-frequency domain features are extracted from the vibration signals. Then, the multi-dimensional features are reduced by OLPP. And the selection of the adjacent paragraph parameters in OLPP is optimized adaptively by minimizing the ratio of between-class distance to within-class distance. A CHMM is trained by using the reduced feature in normal condition. At last, the test bearing data are input into the pre-trained CHMM to calculate the log-likelihood of the test data, which can assess the performance degradation of bearings quantitatively. A bearing accelerated life experiment is performed to validate the feasibility and validity of the proposed method.
Dynamic analysis and optimization of a kinematically redundant planar parallel manipulator
Authors: Boudreau Roger , Léger Jérémie , Tinaou Hakim , Gallant André
Published: April 2018

This paper presents the dynamic model of a kinematically redundant planar parallel manipulator and an optimization method to minimize the actuator torques when the end-effector is subjected to a wrench while following a trajectory. A previous study proposed a static approach to solve the same problem. The objective of the work presented here was to verify if the static assumption was valid. Including the dynamic model in the optimization produced some undesirable oscillations and required the use of a different objective function. It is shown that for the application considered, the static approach provided an acceptable solution.
Simplification of the dynamic model of a hydraulic rockbreaker for implementation in a model-based control scheme
Authors: Tremblay Louis-Francis Y. , Arsenault Marc , Zeinali Meysar
Published: April 2018

A model-based approach to control the automation of hydraulic excavators and rockbreakers necessitates an adequate dynamic model to increase the robustness of the controller and improve its performance (e.g., reduce tracking error). Most previous efforts in developing dynamic models for excavators have assumed planar motion while neglecting the dynamic effects of hydraulically driven prismatic actuators. In this paper, a dynamic model of the mechanical subsystem of a hydraulic rockbreaker is developed using the Euler–Lagrange formulation. The model considers the contributions of the hydraulic actuators and does not assume planar motion. Potential simplifications to the dynamic model are then introduced to facilitate the model’s parameterization for developing an adaptive control algorithm. To evaluate their level of accuracy, these simplified dynamic models are then evaluated based on the required joint torques for specified trajectories. It is shown that the proposed simplifications reduce the complexity of the dynamic model while preserving its accuracy, which is attractive for real-time control applications.
Electrothermal coupling analysis and experimental verification for wirebond devices
Authors: Kao Chin-Li , Chen Tei-Chen
Published: April 2018

The thermal performance of a powered wirebond device with package level and board level test specimens was investigated by both analytical and experiment methods. The effects of thickness and thermal conductivity of the molding compound and heat spreader attached to the top surface of the molding compound on the performance of the Au wire and silicon die were modeled and evaluated by three-dimensional electrothermal coupling analysis. An advanced quad flat no-lead (QFN) sample was selected to experimentally measure the maximum allowable current in Au wire for packages either with or without molding compound. Two failure modes, namely the fusing of the wire and the decomposition temperature of the molding compound, were established in analysis. A board level test specimen with a thermal test die was also employed to measure the real time package thermal performance. The major achievement of this work is in the complete combination of modeling, experiment, and optimization for thermal performance evaluation purpose of a powered wirebond device. Results of this physical analysis can provide a reliable and useful guide to estimate the maximum allowable currents in Au wires for a wirebond device under practical application conditions.
Meshing performance of spiral bevel gear with different loads and modules considering edge contact by finite element method
Authors: Hou Xiangying , Fang Zongde , Fu Xuezhong , Zhang Xijin
Published: April 2018

To analyze the edge contact of spiral bevel gears, owing to its effect on meshing performance, batch processing is performed based on a static solver and the finite element method (FEM) because of its computational speed advantage. A series of programs automatically perform the functions of modeling, analysis, and extraction of performance indexes. Starting from the entrance meshing position to the exit meshing position, a series of models was built and analyzed to describe the whole meshing process of the gear pair. For a specific gear pair, contact and bending stresses, contact stress patterns, loaded transmission errors, contact forces, and load sharing coefficients are calculated under five different load conditions and the change rules are summarized. Edge contact phenomenon occurs as the load increases to a critical value, resulting in a sharp increase in contact stress. As the load increases, the load sharing coefficient decreases gradually and the absolute value of transmission error increases, but the fluctuation of transmission error first decreases and then increases. In addition, the effect of modules is discussed and the results show that large modulus will decrease stress, contact ratio, and edge contact, but there is a certain module to minimize the fluctuation of transmission error.
Study of the temperature configuration of parallel tempering for the traveling salesman problem
Authors: Hasegawa Manabu
Published: April 2018

The effective temperature configuration of parallel tempering (PT) in finite-time optimization is studied for the solution of the traveling salesman problem. An experimental analysis is conducted to decide the relative importance of the two characteristic temperatures, the specific-heat-peak temperature referred to in the general guidelines and the effective intermediate temperature identified in the recent study on simulated annealing (SA). The results show that the operation near the former has no notable significance contrary to the conventional belief but that the operation near the latter plays a crucial role in fulfilling the optimization function of PT. The method shares the same origin of effectiveness with the SA and SA-related algorithms.