bluuebunny/crossref_metadata_2025 huggingface dataset:
ADAPTIVE BACKSTEPPING CONTROL OF A PIEZO-POSITIONING MECHANISM WITH HYSTERESIS
Authors: Zhou Jing , Wen Changyun , Zhang Chengjin
Published: April 2018

Piezo-positioning mechanisms are often used in high-precision positioning applications. Due to their materials, nonlinear hysteretic behavior is commonly observed in such mechanisms and can be described by a LuGre model. In this paper, we develop two robust adaptive backstepping control algorithms for piezo-positioning mechanisms. In the first scheme, we take the structure of the LuGre model into account in the controller design, if the parameters of the model are known. A nonlinear observer is designed to estimate the hysteresis force. In the second scheme, there is no apriori information required from these parameters and thus they can be allowed totally uncertain. In this case, the LuGre model is divided into two parts. While the unknown parameters of one part are incorporated with unknown system parameters for estimation, the effect of the other part is treated as a bounded disturbance. An update law is used to estimate the bound involving this partial hysteresis effect and the external load. For both schemes, it is shown that not only global stability is guaranteed by the proposed controller, but also both transient and asymptotic performances are quantified as explicit functions of the design parameters so that designers can tune the design parameters in an explicit way to obtain the required closed loop behavior.
AN INDEPENDENT ACTIVE BALANCER FOR PLANAR MECHANISMS
Authors: Ying Zhang , Yan-An Yao , Jian-Zhong Cha
Published: April 2018

This paper proposed a novel concept of active balancer for dynamic balancing of planar mechanisms. Somewhat similar to a vibration absorber, the active balancer is designed as an independent device, which is placed outside of the mechanism to be balanced and can be installed easily. It consists of a two degree-of-freedom (DOF) linkage with two input shafts, one of which is connected to the output shaft of the mechanism to be balanced by a joint coupling, and the other one is driven by a controllable motor. Flexible dynamic balancing adapted to different working conditions can be achieved by varying speed trajectories of the control motor actively. A design method is developed for selecting suitable speed trajectories and link parameters of the two DOF linkage of the balancer to meet various design requirements and constraints. Numerical examples are given to demonstrate the design procedure and to verify the feasibility of the proposed concept.
MODELING AND MANUFACTURING OF PP-TYPE SINGLE SCREW COMPRESSOR
Authors: Shyue-Cheng Yang , Liang Tsang-Lang
Published: April 2018

A geometric model and a mathematical model of a PP-type single screw rotor with planar gate rotor are derived from the gate-rotor generation process and gear theory. The teeth of gate rotor are planar. Based on the inverse envelope concept, the cutter required for machining the single screw rotor can be obtained using an inverse envelope of a one-parameter family of screw surfaces. The surface of the proposed screw rotor is analyzed using the developed mathematical model. A surface analysis, including stress analysis, of the design and manufacture of the screw compressor is presented. Finally, a numerical example demonstrates the geometric model of the PP-type single screw rotor with a compression ratio of 11:6.
OPTIMIZATION OF REALISTIC REFRIGERATION PLANT UNDER FIXED TOTAL THERMAL CONDUCTANCE CONSTRAINT
Authors: Chang Tong-Bou
Published: April 2018

This study analyzes the internal irreversibility of a realistic refrigeration plant under the design constraint of a fixed total thermal conductance. The internal heat losses are determined using a heat by-pass model. The optimal thermal conductance allocation and optimal coefficient of performance are derived from a series of detailed analyses and formulations. The numerical results indicate that the optimal thermal conductance ratio of the hot end of a realistic refrigeration plant is slightly higher than 0.5.
KINEMATIC MODELLING AND ANALYSIS OF A WIRE-ACTUATED PARALLEL MANIPULATOR
Authors: Sahin Sureyya , Notash Leila
Published: April 2018

The kinematic modelling and analysis of a 4 degrees of freedom wire-actuated parallel manipulator with redundant actuation is investigated. The manipulator employs combinations of rigid links, joints and wires. Hybrid actuation of joints and wires, two actuated joints and three actuated wires, is used. Position and first and second order kinematics of the closed-loop manipulator are formulated based on matrix exponentials. The transfer of first and second order kinematic variables, i.e., wire/joint velocities and accelerations, among the manipulator task space coordinates, active and passive joint coordinates and wire lengths are provided.
DEXTEROUS TASK-PRIORITY BASED REDUNDANCY RESOLUTION FOR UNDERWATER MANIPULATOR SYSTEMS
Authors: Soylu Serdar , Buckham Bradley J. , Podhorodeski Ron P.
Published: April 2018

The problem of redundancy resolution for underwater remote vehicle-manipulator systems (URVM) is addressed in the current work. In URVM applications, it is beneficial to have the underwater remote vehicle (URV) hold station using its thrusters while a human pilot operates the serial manipulator. This provides a stable platform for the manipulator and eases the pilot’s job drastically when current and/or tether disturbances are present. However, when following this objective, the redundancy of the URVM as a whole is wasted; the four actively controlled motions of the URV are not used to improve the efficacy of the manipulator task. In fact, this standard operating procedure frequently puts the manipulator into near singular configurations. This is not desirable from the manipulator controller standpoint since near singular configurations result in undesirably high joint velocities and oscillations. In this work, a new heuristic approach based on the task-priority redundancy resolution scheme is applied to the URVM. The proposed approach provides a means to avoid singular configurations of the manipulator, and provides dexterous manipulation by using the URV’s mobility in an optimal, coordinated manner. This scheme is particularly useful for remote systems where an a priori trajectory generator is not applicable. Numerical case studies are developed to demonstrate the effectiveness of the technique.
AN EXPERIMENTAL STUDY ON FATIGUE CHARACTERISTICS FOR VISCOELASTIC SUSPENSIONS OF CONSTRUCTION VEHICLES
Authors: Sun Da-Gang , Song Yong , Zhang Xue-Liang , Lin Mu-Yi
Published: April 2018

To acquire the fatigue characteristics of viscoelastic suspensions mounted in newly-developed construction vehicles, an experimental study of fatigue characteristics should be carried out on the vibration damping rubber suspension components. However, due to the lack of corresponding fatigue failure criteria for the damping rubber components, how to determine the parameters for the accelerated fatigue experiments becomes a new research subject. Based on the accelerated fatigue experiments on the viscoelastic suspensions, the parameters on fatigue failure characteristics such as the cycle index (ne), the slope (k) of S–N logarithm curve and the allowable temperature rise, and so on, were investigated. To develop a new viscoelastic suspension for the crawler bulldozer, three types of rubber made from different formulas for the viscoelastic suspensions were studied and their experimental loads were divided into 8 levels in terms of the practical working conditions of the bulldozer. The accelerated fatigue experiments of viscoelastic suspensions were performed and the obtained parameters were applied to the fatigue experiments for the suspensions of a newly-designed 386 kW crawler bulldozer. Under the industrial application over 4,000 hours, the results were shown to be consistent with the predicted experimental values.
SOFT BODY IMPACT SIMULATION ON COMPOSITE STRUCTURES
Authors: Ensan M. Nejad , Zimcik D.G. , Lahoubi M. , Andrieu D.
Published: April 2018

The paper describes recent progress on numerical simulation of soft body impact onto a fibre reinforced composite wing leading edge structure. The work is based on the application of non-linear explicit finite element analysis to simulate the response of composite wing structures under soft body impact loads. Soft body impactors such as gelatine (substitute bird) or ice (hailstones) are highly deformable on impact and flow over the structure spreading the impact load. Therefore, first benchmark simulations were carried out for soft body impact onto a rigid target. Soft body impactor was modeled using the Arbitrary Lagrangian-Eulerian (ALE) method. The results obtained using this impact model for different velocity were compared to the experimental test results in terms of local pressure, including Hugoniot and stagnation pressures, and global load to validate the accuracy of the model. Then, the impact of soft body onto a composite wing structures was described. A composite failure model which includes ply damage and interplay delamination model has been used to predict impact damage in the structure modeled using shell elements. The simulation tool predicts the impact damage in leading edge structure.
FUNDAMENTALS OF THE SQUEEZE-FLOW BETWEEN A HEAT SINK AND A FLIP-CHIP
Authors: Marois M.A. , Lacroix M.
Published: April 2018

The paper presents the fundamentals of the squeeze-flow of the thermal interface material (TIM) that takes place during the pressing of a heat sink to the back side of a flip-chip is studied. A two-dimensional string model is developed for predicting the time-varying plate separation and squeeze-rate in terms of the squeeze force. The predictions are compared to a one-dimensional string model and to a squeeze-drop flow model. Results indicate that the flow resulting from the squeezing of a string of TIM between two rigid plates is truly two-dimensional. The effect of surface tension and of the heat transfer is found to be negligible under the assembly conditions. The flow behaviour of the TIM with suspensions of high thermal conductivity particles is also investigated. It is shown that the fluid remains Newtonian for particle volume fractions smaller than 30%. For volume fractions larger than 30%, the fluid becomes Non-Newtonian during the early stages of the squeezing process, i.e. for t ≤ 1s. In the later stages however (t > 10s), the fluid may be considered Newtonian.
OPTIMIZATION OF ICEBERG TOWING VELOCITY FOR WATER SUPPLY
Authors: Lefrançois Simon , Doyon-Poulin Philippe , Gosselin Louis , Lacroix Marcel
Published: April 2018

A mathematical model for determining the optimum towing velocity of tabular icebergs is presented. The optimization problem is formulated in terms of a benefit function that takes into account the ice mass delivered and the total fuel consumption for the tow. Results indicate that the optimum towing velocity is mainly affected by the water-to-fuel cost ratio. It is shown that towing icebergs from Antarctica to South Africa is a profitable way of supplying fresh-water provided that the towing velocity is optimized with the proposed method.
FEASIBILITY OF COMBINED HEAT AND POWER SYSTEM IN THE CENTRAL BUSINESS DISTRICT OF SHANGHAI
Authors: Xuan Ji , Gao Weijun
Published: April 2018

As one of the most developed and energy intensive cities in China, the Shanghai’s municipal government tries to make Shanghai one of the leading cities of energy conservation in China. Expanding the use of combined heat and power (CHP) system is the one of the main ways to optimize Shanghai’s energy structure and to protect its environment. This paper aims to analyze the feasibility of introducing CHP in the central business district, in Shanghai, to determine the energy savings, environmental impact and economic efficiency. Three types of energy supply systems are considered: electricity-only system, 2 CHP systems with electric tracking and thermal tracking. Relative to the conventional electricity-only system, the CHP systems are capable of reducing the primary energy consumption by approximately 24% and 4%, CO2 emission by 38% and 11%, respectively. For CHP, although the initial costs are often substantially higher than a conventional system, it is expected to dramatically reduce the cost of running. The result shows if introducing CHP, it only takes approximately 5 years can return the initial investment, in each case. This implies that the introduction of CHP can achieve high profitability.
MODELING AND OPTIMIZATION OF AN AMMONIA-WATER COMPRESSION-RESORPTION HEAT PUMPS WITH WET COMPRESSION
Authors: Zamfirescu Calin
Published: April 2018

Wet ammonia-water compression-resorption heat pumps constitute an attractive alternative to the commonly known heat pumps based on Osenbrück cycle because they eliminate the necessity of oil-liquid refrigerant separation. In this respect, a special designed oil-free compressor operating under wet (two-phase) conditions equips the heat pump. The compressor is lubricated by the liquid refrigerant which is carried-out while compressing the vapor. The thermodynamic cycle is located completely inside the two-phase region. In this paper are demonstrated two procedures to optimize the design for COP maximization. It is shown that there is: (i) an optimal choice of the vapor quality at suction, and (ii) an optimal distribution of heat transfer surface between the resorber and the desorber (the total amount of heat transfer surface, being an expression of investment cost, is fixed). The circulating concentration of ammonia has to be chosen such that the minimum pressure in the system is over one bar (to avoid air penetration from the atmosphere) and the maximum pressure is bounded by a technical-economical maximal limit. A general procedure for calculation of the optimal cycle parameters is presented and exemplified for a case with practical relevance. The paper presents only the trends and rough quantitative estimations because the analyzed case is restricted to the ideal isentropic compression. Further research is needed to quantify in detail the effect of compression irreversibility.
NUMERICAL AND EXPERIMENTAL ANALYSES OF THE FLOW AROUND A HORIZONTAL WALL-MOUNTED CIRCULAR CYLINDER
Authors: Akoz M. Sami , Kirkgoz M. Salih
Published: April 2018

The numerical modeling of two-dimensional turbulent flow around a horizontal wall-mounted circular cylinder at Reynolds numbers in the range of 1000≤ReD≤7000 is investigated. Ansys® 10.0-FLOTRAN program package is used to solve the governing equations by finite element method, and the performance of the standard k-ε, standard k-ω and SST turbulence models are examined. A sensitivity study for the three turbulence models is carried out on eight computational meshes with different densities and structures. The computational velocity fields from the present simulations are compared with the experimental results obtained from particle image velocimetry (PIV) measurements for validation purposes. The point of the boundary layer detachment from the cylinder surface and the lengths of primary and secondary separation regions occurring around the cylinder are determined numerically and compared with those obtained experimentally. From these comparisons it is found that the numerical modeling using either of k-ω and SST turbulence models is reasonably successful. Using the results of numerical solutions, the drag and lift coefficients, Cd and Cl, are also calculated and compared with the measured values.
A TIME-PHASED PRODUCTION SCHEDULING SYSTEM FOR MULTIPLE ORDER WITH SINGLE ITEM
Authors: Lan Chun-Hsiung , Liu Kuo-Chien
Published: April 2018

A mathematical model which minimizes the production cost of an automatic and networktype multiple-order-production (MOP) system with restriction of time-phased order completion is presented. A step-by-step algorithm is described to find the minimal cost of production. In order to solve the combinatorial problems of the production rate, the machine cost, and numerous machines in parallel at each workstation of the production line, a feedback approach is also applied in the algorithm. An example of a large number of orders which is subdivided into different deadlines is shown to demonstrate the application of the algorithm that results in decreased production cost, enhanced production rate, improved efficiency of the production schedule, and on-time completion of production.
ON THE FORCES AND STROUHAL NUMBERS IN THE LOW REYNOLDS NUMBER WAKES OF TWO CYLINDERS IN TANDEM
Authors: Zheng Tinghui , Tang S. K. , Fei Baoling
Published: April 2018

The flow around two circular cylinders of equal diameter in tandem arrangement was investigated numerically using the finite volume method in the present study. The code was validated by comparison with previous works at the Reynolds number of 200. A systematic investigation of the relationships of Strouhal number and the aerodynamic forces with cylinder separation and Reynolds number was done. Results demonstrate not only the important combined effects cylinder separation and Reynolds number on the wake aerodynamics, but also on the relative strengths of the forces acting on the two cylinders (both mean and fluctuations)
CALCULATION OF MODULATION TRANSFER FUNCTION OF AN OPTICAL SYSTEM BY USING SKEW RAY TRACING
Authors: Tseng Kuo-Hwa , Kung Chieh , Liao Te-Tan , Chang Hao-Peng
Published: April 2018

The resolution and performance of an optical system can be characterized by a quantity known as the modulation transfer function (MTF), which is a measurement of an optical system’s ability to transfer contrast from the specimen to the intermediate image plane at a specific resolution. Accordingly, this study employs skew ray tracing based on a 4 × 4 homogeneous coordinate transformation matrix and Snell’s law to develop a detailed methodology for determining the spot diagram on the image plane when light rays pass through the optical system. And the authors present calculations of the MTF of an optical system by using the spot diagram on the image plane. The numerical results of the proposed methodology are demonstrated using a symmetrical optical system.
SYMBOLIC TREATMENT FOR THE EQUATIONS OF MOTION FOR RIGID MULTIBODY SYSTEMS
Authors: Ikoki Bukoko C. , Richard Marc J. , Bouazara Mohamed , Datoussaïd Sélim
Published: April 2018

The library of symbolic C++ routines is broadly used throughout the world. In this article, we consider its application in the symbolic treatment of rigid multibody systems through a new software KINDA (KINematic & Dynamic Analysis). Besides the attraction which represents the symbolic approach and the effectiveness of this algorithm, the capacities of algebraical manipulations of symbolic routines are exploited to produce concise and legible differential equations of motion for reduced size mechanisms. These equations also constitute a powerful tool for the validation of symbolic generation algorithms other than by comparing results provided by numerical methods. The appeal in the software KINDA resides in the capability to generate the differential equations of motion from the choice of the multibody formalism adopted by the analyst.
DETERMINATION OF THE ANALYTICAL WORKSPACE BOUNDARIES OF A NOVEL 2-DOF PLANAR TENSEGRITY MECHANISM
Authors: Arsenault Marc
Published: April 2018

Tensegrity mechanisms are slowly emerging as potential alternatives to more conventional mechanisms for certain types of applications where a reduced inertia of the mobile parts and a high payload to weight ratio are sought. With this in mind, a two-degree-of-freedom planar tensegrity mechanism is developed using a simple actuation strategy to keep the mechanism in self-stressed configurations. Solutions to the mechanism’s direct and inverse kinematic problems are first developed and are then used to determine analytical expressions for its workspace boundaries.
A NEW ALGORITHM FOR U-SHAPED TWO-SIDED ASSEMBLY LINE BALANCING
Authors: Yegul Mustafa Fatih , Agpak Kursad , Yavuz Mustafa
Published: April 2018

This study introduces a new hybrid design for a specific case of assembly lines, and proposes a multi-pass random assignment algorithm to find the minimum number of stations required. The algorithm also finds the sequence and the schedule of the tasks assigned. The new design is a combination of two-sided lines and U-shaped lines, which benefits from the advantages of both designs at the same time. One side of the line is arranged in U-shape allowing stations with crossovers, and the other side of the line is balanced like a traditional straight flow. Depending on product direction, either Left or Right side of the line can be designed in U-shape. Small and large-sized two-sided assembly line test-bed problems were solved using the algorithm. Optimal results are achieved for all small-sized problems. Due to the novelty of the design, results of largesized problems are compared to findings of studies on simple two-sided balancing. Algorithm produced better results in most of the cases.
FUZZY TAGUCHI DEDUCTION OPTIMIZATION ON MULTI-ATTRIBUTE CNC TURNING
Authors: Lan Tian-Syung
Published: April 2018

In this paper, four parameters with three levels are considered to optimize the multi-attribute finish CNC (computer numerical control) turning based on L9(34) orthogonal array. Additionally, nine fuzzy control rules with respective to five linguistic grades for each attribute are constructed. The TOPSIS (Technique for Order Preference by Similarity to Ideal Solution) is moreover utilized to integrate and evaluate the multiple machining attributes for Taguchi experiment to receive the optimum general deduction parameters. It is shown that the attributes from the fuzzy Taguchi deduction optimization parameters are all significantly advanced comparing to those from benchmark.
NUMERICAL ANALYSIS OF DISPLACEMENTS IN SPATIAL MECHANISMS WITH SPHERICAL JOINTS UTILIZING AN EXTENDED D-H NOTATION
Authors: Hsieh Jung-Fa
Published: April 2018

Spherical joints consist of a pair of concave and convex spherical surfaces engaged in such a way as to prevent translational motion of the ball and socket whilst simultaneously allowing three degrees of rotational freedom. The kinematics of spatial mechanisms comprising links and joints are commonly analyzed using the Denavit-Hartenberg (D-H) notation. However, whilst this method allows the kinematics of mechanisms containing prismatic, revolute, helical and cylindrical joints to be explicitly defined, it cannot be directly applied to mechanical systems containing spherical pairs. Accordingly, this paper proposes an extended D-H notation which allows the independent parameters of any spatial mechanism, including one with spherical pairs, to be derived for analysis and synthesis purposes. The validity of the proposed notation is demonstrated via its application to the analysis of mechanisms containing revolute (R), spherical (S), cylindrical (C) and prismatic (P) joints. The results confirm the viability of the extended D-H notation as a means of analyzing the displacements of mechanical systems containing kinematic chains such as RSCR, RSCP, CSSR and CSSP.
PARETO BASED MULTI-OBJECTIVE OPTIMIZATION OF SOLAR THERMAL ENERGY STORAGE USING GENETIC ALGORITHMS
Authors: Khalkhali Abolfazl , Sadafi Mohamadhosein , Rezapour Javad , Safikhani Hamed
Published: April 2018

Net energy stored (Q net) and the discharge time of Phase Change Material (t PCM) in a solar system, are important conflicting objectives to be optimized simultaneously. In the present paper, multi-objective genetic algorithms (GAs) are used for Pareto approach optimization of a solar system using modified NSGA II algorithms. The competing objectives are Q net and t PCM and design variables are some geometrical parameters of solar system. It is shown that some interesting and important relationships as useful optimal design principles involved in the performance of solar system can be discovered. These important results can be used for better design of a solar system.
CLIMBING MODEL AND OBSTACLE-CLIMBING PERFORMANCE OF A CABLE INSPECTION ROBOT FOR A CABLE-STAYED BRIDGE
Authors: Xu Feng-yu , Wang Xing-song , Wang Lei
Published: April 2018

A cable inspection robot is proposed to automatically check the cables of a cable-stayed bridge. First, a climbing model supported by an independent spring and an inspection robot is designed. Second, the dimensionless parameter, h/r, which is the ratio of the vertical height of the obstacle to the radius of the obstacle-climbing wheel, is selected as the evaluation standard of the climbing ability of the robot; after which a mathematical model of such obstacle-climbing ability is established. Third, the bearing capacity of the driving wheel rubber is studied using the finite element method. Afterwards, the analysis of the climbing performance is then carried out through simulation by studying two influential perspectives, namely, the positive pressure from the passive end spring and the swinging angle of the passive wheel. Finally, field experiments are carried out on the HuangPu Cable-Stayed Bridge. Based on the results, the robot can climb steadily on various inclined cables.
ADAPTIVE FINITE ELEMENT METHOD TO DETERMINE KI AND KII OF CRACK PLATE WITH DIFFERENT EINCLUSION/EPLATE RATIO
Authors: Limtrakarn Wiroj , Dechaumphai Pramote
Published: April 2018

An adaptive finite element method is presented to determine the KI and KII stress intensity factors of crack plate with different inclusions. The paper starts from describing two-dimensional fracture mechanics theory, an adaptive finite element formulation and the reflection photoelastic technique. An adaptive finite element method is evaluated by analyzing two examples. A single edge cracked plate made from polycarbonate. The second example is the slant edge 45° cracked plate subjected to a uniform uniaxial tensile stress. The KI and KII results are found to be function of the crack length per width and the inverse function of E ratio. These examples demonstrate the efficiency of the adaptive finite element method to provide accurate solutions as compared to those from the reflection photoelastic technique.
DYNAMIC ANALYSIS OF A ROTARY HOLLOW SHAFT WITH HOT-FIT PART USING CONTACT ELEMENTS WITH FRICTION
Authors: Chen Shin-Yong , Kung Chieh , Hsu Jung-Chun
Published: April 2018

One of the key factors in designing a motor built-in high speed spindle is to assemble the motor rotor and shaft by means of hot-fit. Presented in this paper is a study of the influence of a hot-fit rotor on the local stiffness of the hollow shaft. Dynamic analyses of the rotor-hollow shaft assembly using contact elements are conducted. The normal contact stress state between the rotor and the hollow shaft is obtained through the use of contact elements with friction effects included. The normal contact stress, considered as the pr-stress between the rotor and the hollow shaft, is then adopted for subsequent modal analyses. In this study, the modal analysis results are verified by a modal testing experiment. The percent errors of the first natural frequency and the second natural frequency are down to about 0.58% and 0.79%, respectively.
INVESTIGATION OF EFFECT ON LATERAL DISPLACEMENT AND FORCES OF CUTTING MODE IN SAWABILITY OF METAL PROFILE USING CUTTING DISC
Authors: Ucun İsmail
Published: April 2018

In this study, the cutting performance of cutting discs used to cut metal materials depending on the cutting modes is determined with an experimental study. Tests are performed using a computer-controlled cutting machine. For the tests, peripheral speeds of 40, 60 and 80 m/sec and feed speeds of 0.3, 0.4, 0.5, 0.6, and 0.7 m/min. are preferred as cutting parameters. Up cutting and down cutting are taken into consideration as cutting modes. A three-point dynamometer is used to determine the forces applied on the disc during cutting. A KEYENCE laser displacement measuring device is used to measure lateral displacements of the cutting disc. According to the test results, feed speed is observed as a significant parameter in determining the cutting forces and lateral displacements. Up and down cutting modes used in the study has a significant effect on determining the forces applied on the cutting disc and lateral displacements of the disc. In particular, lateral displacements obtained in down cutting mode are observed to be greater than the displacements obtained in up cutting mode.
METHODOLOGY OF THE ASSESSMENT OF THE ABRASIVE TOOL’S ACTIVE SURFACE USING LASER SCATTEROMETRY
Authors: Kapłonek Wojciech , Łukianowicz Czesław , Nadolny Krzysztof
Published: April 2018

Diagnostics of abrasive tools requires the use of modern measurement techniques which allows for fast assessment of a surface in order to determine, for example, the degree of its wear or to detect various type of defects. A wide group of optical measurement methods used for this type of assessment are based on the phenomenon of light scattering. One such method based on imaging and analysis of light scattering from a surface is laser scatterometry. In this paper, by utilizing laser scatterometry supported by image analysis techniques, a proposal for a methodology of assessment of the degree to which smearing of the grinding wheel active surface (GWAS) occurs during the plunge grinding process, was presented and discussed. Select results of experimental investigations carried out on bearing steel 100Cr6 were also presented. The obtained results confirmed the efficacy of the above-mentioned techniques that could be an interesting alternative to other methods already used in such measurements.
RESEARCH ON THEORY AND APPLICATIONS OF VIRTUAL TOLERANCE
Authors: Xiaohui Wang , Shouhua Ren
Published: April 2018

Tolerance where the upper deviation is smaller than the lower deviation is defined as virtual tolerance. The essence of virtual tolerance is illustrated in this paper: the absolute value of virtual tolerance is the amount of error compensation whose range is the difference between the upper deviation and the lower deviation. This value can be described as virtual tolerance and provides a basis for the theory of tolerance. Based on this theory, we can unify calculation principles and methods regarding various types of assembly dimension chains, accurately calculate the tolerance of dimensional chains for assembly with compensation assemblies, and put forward a general calculation method for false waste product intervals.
CONTROLLABLE WORKSPACE OF CABLE-DRIVEN REDUNDANT PARALLEL MANIPULATORS BY FUNDAMENTAL WRENCH ANALYSIS
Authors: Loloei Azadeh Zarif , Taghirad Hamid D.
Published: April 2018

Workspace analysis is always a crucial issue in robotic manipulator design. This paper introduces a set of newly defined fundamental wrenches that opens new horizons to physical interpretation of controllable workspace of a general cable-driven redundant parallel manipulator. Based on this set of fundamental wrenches, a novel tool is presented to determine configurations of cable-driven redundant parallel manipulator that belong to the controllable workspace. Analytical expressions of such workspace boundaries are obtained in an implicit form and a rigorous mathematical proof is provided for this method. Finally, the proposed method is implemented on a spatial cable-driven manipulator of interest.
MULTI-BEAM LASER HEATING OF STEEL: TEMPERATURE AND THERMAL STRESS ANALYSIS
Authors: Shuja Shahzada Zaman , Yilbas Bekir Sami
Published: April 2018

Laser multi-beam heating of steel sheet surface is considered. The irradiated laser spots are located along an arc to increase heated surface area during laser scanning at a constant speed. Temperature and stress fields are predicted for various number of spots along the arc. It is found that temperature and stress fields in the irradiated substrate can be controlled through proper selection of the number of irradiated spots along the arc. Increasing number of irradiated spots results in development of almost uniform high temperature and high stress fields around the arc; however, local heating and discontinuous stress field giving rise to large differences in von Mises stress occurring for reduced number of spots in the arc.
IMPROVING THE FORMABILITY OF STAINLESS STEEL 321 THROUGH MULTISTEP DEFORMATION FOR HYDROFORMING APPLICATIONS
Authors: Anderson Melissa , Gholipour Javad , Bridier Florent , Bocher Philippe , Jahazi Mohammad , Savoie Jean , Wanjara Priti
Published: April 2018

Tube hydroforming (THF) is a well established process in the automotive industry and its application is being extended to the aerospace for manufacturing complex geometries. However, most of the alloys used in aerospace are high in strength and low in formability, which renders the application of THF more challenging. The objective of this paper is to present a method to increase the formability of an austenitic stainless steel. A multistep forming process was simulated through interrupted uniaxial tensile testing experiments to study the influence of the latter process on formability. The tensile test was divided into several deformation steps with a stress relief heat treatment after each forming step. The results indicated that the application of intermediate heat treatments considerably increased the formability of the stainless steel 321 alloy (SS321). Microstructure evolution as a function of deformation or heat treatment parameters was also investigated and revealed the formation of strain-induced martensite after the first deformation and heat treatment cycle without any deleterious effect on formability enhancement.
USE OF SPATIOTEMPORAL DIAGRAMS TO CHARACTERIZE A SILO DISCHARGING PROCESS
Authors: Nsom Blaise , Latrache Noureddine
Published: April 2018

To get a better knowledge of discharging flows of ensiled granular materials, a small scale silo was designed and built. It is equipped with a flat bottom and it has a rectangular cross section. Moreover, it is entirely transparent for image processing purpose. First of all, a physical and mechanical characterization of wood granules (inert materials) was performed using a shear box testing. Then, silo emptying flows were generated. Flow regimes and flow rate were determined using spatiotemporal diagrams extracted from images of the free surface of the ensiled material. The same method was then used to measure the flow rate of discharging flows of soya, colza and rye seeds which were characterized in a previous study. For each material studied, the flow rate measured with this non intrusive method was successfully compared with a direct method consisting in weighing a volume of grains discharged during a unit time and with Berveloo’s formula.
MOTION PLANNING FOR 6-DOF ASSEMBLY PART POSITIONING AND ALIGNMENT ADJUSTMENT
Authors: Hong Jun , Wang Shao F. , Chukwuma Emenike , Zhang Jing H. , Liu Zhi G.
Published: April 2018

In this paper, a 4-PPPS redundantly actuated parallel mechanism and its motion planning method are proposed. The mechanism can be applied to the positioning and alignment of large subassembly in engineering assembly. The optimization of the positioning and alignment trajectory is performed with the minimum energy consumption as the objective function. The system test data shows that the assembly platform and the motion planning method can satisfy the requirements of accuracy, efficiency and stability of the positioning and alignment operations.
FUZZY SIMPLEX-TYPE SLIDING-MODE CONTROL
Authors: Chen Ta-Tau , Kuo Sung-Chun
Published: April 2018

In this paper, a novel fuzzy simplex sliding-mode controller is proposed for controlling a multivariable nonlinear system. The fuzzy logic control (FLC) algorithm and simplex sliding-mode control (SSMC) theory are integrated to form the fuzzy simplex sliding mode control (FSSMC) scheme which improves the system states response and reduces system states chattering phenomenon. In this paper, at first, we introduce the principle of simplex method, and then develop fuzzy controls based on the simplex method. Finally, a numerical example is proposed to illustrate the advantages of the proposed controllers, the simulation results demonstrate that the fuzzy simplex type sliding mode control scheme is a good solution to the chattering problem in the simplex sliding mode control.
A PRACTICAL TRAJECTORY TRACKING APPROACH FOR AUTONOMOUS MOBILE ROBOTS: NONLINEAR ADAPTIVE H2 DESIGN
Authors: Chen Yung Hsiang , Li Tzuu Hseng S. , Chen Yung Yue
Published: April 2018

A nonlinear adaptive trajectory tracking design for autonomous mobile robot and its practical implementation are presented in this paper. This approach can be applied to generate trajectory tracking control commands for autonomous mobile robot tracking predefined trajectories. The design objective is to specify one nonlinear controller with a parameter adaptive law that satisfies the adaptive H2 optimal performance. In general, it is hard to obtain the closed-form solution from this nonlinear trajectory tracking problem. Fortunately, based on the property of the trajectory tracking error dynamic system of the autonomous mobile robot, one closed-form solution to this problem can be obtained with a very simple form for the preceding control design.
EFFECTIVE DYNAMIC STIFFNESS MODEL AND ITS EFFECTS ON ROBOT SAFETY AND PERFORMANCE
Authors: Shin Dongjun , Quek Zhan Fan
Published: April 2018

Due to the limited control bandwidth of pneumatic artificial muscles, joint stiffness characteristics and their effects on safety and performance of human-friendly robots should be considered in the frequency domain. This paper introduces the concept of effective dynamic stiffness and validates its model with the Stanford Safety Robot. Experimental results show that the dynamic stiffness demonstrates limited effects on the impact acceleration given the same impact velocity and controller gain, whereas it significantly affects control performance of position tracking due to pressure-induced non-linearities. A stiffness optimization strategy for safety and performance is discussed as a design guideline of human-friendly robots.
A MODIFIED Z-MAP COMPUTATIONAL INTERPOLATION ALGORITHM FOR SURFACE MACHINING SIMULATION
Authors: Tsai Jo-Peng
Published: April 2018

The Z-Map algorithm is one of the most simplistic methods for NC code simulation in obtaining the machined working surface information; therefore, it is often being applied in NC simulation. In this paper, a modified Z-Map computational algorithm was proposed to calculate mesh position and Z coordinates of tool scanning surface according to tool path and initial tool scanning boundary in reducing the long computation time. The proposed algorithm not only can be used to derive straight line and arc machining tool path, but also can be adopted for helical and spline curves. There is no need to simplify the non-linear curves beforehand. The method proposed in this paper provides a feasible reference for decision about the reliability and suitability of each machining step.
ADAPTIVE ITERATIVE LEARNING CONTROL OF ROBOTIC SYSTEMS USING BACKSTEPPING DESIGN
Authors: Wang Ying-Chung , Chien Chiang-Ju , Chuang Chi-Nan
Published: April 2018

In this paper, a backstepping adaptive iterative learning control (AILC) is proposed for robotic systems with repetitive tasks. The AILC is designed to approximate unknown certainty equivalent controller. Finally, we apply a Lyapunov like analysis to show that all adjustable parameters and the internal signals remain bounded for all iterations.
IMPROVING EIGENSPACE-BASED FUZZY LOGIC SYSTEM USING A LINEAR INTERPOLATION SCHEME FOR SPEECH PATTERN RECOGNITION
Authors: Ding Ing-Jr , Yen Chih-Ta
Published: April 2018

The Eigen-FLS approach using an eigenspace-based scheme for fast fuzzy logic system (FLS) establishments has been attempted successfully in speech pattern recognition. However, speech pattern recognition by Eigen-FLS will still encounter a dissatisfactory recognition performance when the collected data for eigen value calculations of the FLS eigenspace is scarce. To tackle this issue, this paper proposes two improved-versioned Eigen-FLS methods, incremental MLED Eigen-FLS and EigenMLLR-like Eigen-FLS, both of which use a linear interpolation scheme for properly adjusting the target speaker’s Eigen-FLS model derived from an FLS eigenspace. Developed incremental MLED Eigen-FLS and EigenMLLR-like Eigen-FLS are superior to conventional Eigen-FLS especially in the situation of insufficient data from the target speaker.
THE INNOVATIVE DESIGN OF AUTOMATIC TRANSMISSIONS FOR ELECTRIC MOTORCYCLES
Authors: Hsieh Long-Chang , Tang Hsiu-Chen
Published: April 2018

Due to the reason of pollution-free, electric motorcycle become more and more popular in city traffic. The purpose of this work is to propose a design methodology for the invention of planetary gear automatic transmissions for electric motorcycles. First, applying the check list method (combining and extending methods), the design concepts are proposed. Then, based on the train value equation of planetary gear train, we derive reduction-ratio equations of these planetary gear automatic transmissions. In this paper, five new design concepts including three 3-speed and two 4-speed are synthesized. Three examples of the kinematic design of planetary gear automatic transmissions are accomplished to illustrate the design methodology.
ANALYSIS OF NO FORMATION IN COUNTER-FLOW PREMIXED HYDROGEN-AIR FLAME
Authors: Xie Tianfang , Wang Peiyong
Published: April 2018

Though hydrogen fuel reduces the carbon dioxide emission, it still produces NOx. However, gaps exist in the fundamental understanding of hydrogen-air combustion and the NO emission; most previous research has focused on the flames burning with mixture such as H2 mixed with CH4, rather than pure H2 flame. Here, a computational study is presented to investigate the stretch effect on NO formation in counter-flow premixed hydrogen-air flame. The simulation of premixed hydrogen flame was performed with OPPDIF code and UCSD chemical mechanism. Result indicates that the NO formation is affected by three factors: radical concentration, flame temperature, and residence time of reactants. The flame temperature, the reaction rate of NO, and the NO emission index all decrease when the stretch rate increases. Moreover, the formation of NO through thermal mechanism, NNH mechanism, and N2O mechanism is discussed, as well as the percentage of their contribution.
INK JET PRINTED THIN FILMS ON GLASS AND POLYIMIDE SUBSTRATES
Authors: Li Tsai-Cheng , Chang Rwei-Ching , Li Yen-Choung
Published: April 2018

Silver conductive thin films deposited on glass and polyimide substrates by using ink jet printing are studied in this work. Characterization of the printed thin films and comparison with sputtered films are investigated. The micro texture, residual stress, adhesion, hardness, optical reflectance, and electric resistance of the thin films are discussed. The result shows that the ink jet printing has the possibility to replace sputtering in thin film deposition, especially for the polymer substrates.
HYBRID MODIFIED ELMAN NN CONTROLLER DESIGN ON PERMANENT MAGNET SYNCHRONOUS MOTOR DRIVEN ELECTRIC SCOOTER
Authors: Lin Chih-Hong , Lin Chih-Peng
Published: April 2018

The electric scooter driven by permanent magnet synchronous motor (PMSM) has nonlinear and time-varying characteristic. An accurate dynamic model is not easy to establish for electric scooter in the linear controller design. In order to conquer the above problem, a novel hybrid modified Elman neural network (NN) control scheme is proposed to control for electric scooter driven by PMSM. The proposed control system consists of a supervisor control, a modified Elman NN and a compensated control with adaptive law. Finally, the effectiveness of the proposed novel hybrid modified Elman NN control system is demonstrated in comparison with the PI controller from some experimental results.
HYDRAULIC SYSTEM FAULT DIAGNOSIS BASED ON EMD AND IMPROVED PSO-ELMAN ANN
Authors: Dong Zengshou , Zhang Xiaoyu , Zeng Jianchao
Published: April 2018

The element parameters of engineering machinery hydraulic system are detected, the fault eigenvector is extracted, and the information is applied to neural network fault diagnosis. Experience mode decomposition (EMD) is used to extract fault characteristic vectors in this paper, combined with the pressure, temperature and flow rate of dominant signal as neural network’s inputs. In addition, the paper improves the Elman neural network learning algorithm by the PSO algorithm. It can effectively increase network convergence rate and computing power. The particle swarm is used to optimize Elman neural network weights and the threshold value and then applied in the fault diagnosis system by training the network. The results show that the method increases the neural network convergence rate and reduces diagnoses error.
AN EXPERIMENTAL STUDY ON FRICTION DRILLING OF ST12 STEEL
Authors: Kaya Mehmet Tuncay , Aktas Alaattin , Beylergil Bertan , Akyildiz Hamza K.
Published: April 2018

The aim of this study is to investigate the effects of drilling parameters such as friction angle, friction contact area ratio (FCAR), feed rate and spindle speed on workpiece surface temperature, thrust force and torque in friction drilling of ST12 material. The tool material is tungsten carbide coated with TiN treatment. Experimental results reveal that the thrust force and torque increases gradually with increasing friction angle, feed rate and FCAR. On the other hand, the thrust force and torque decreases with increasing drilling speed. It is found that drilling speed has an important effect on the workpiece surface temperature. As the drilling speed increases, the workpiece surface temperature increases. Increasing or decreasing the friction angle and FCAR has no significant effect on the workpiece surface temperature.
INVESTIGATION ON ELECTROMAGNETIC FORCES AND EXPERIMENTAL VIBRATION CHARACTERISTICS OF STATOR END WINDINGS IN GENERATOR
Authors: Wan Shuting , Zhan Changgeng , Yao Xiaofang , Deng Yanmin , Zhou Guowei
Published: April 2018

This paper investigates the electromagnetic forces acting on the stator end windings, by using the stator end windings structure of a 600 MW large-capacity turbo-generator as the analysis object. Firstly, based on the method of images, the Biot–Savart Law and superposition theorem, the calculation model of the stator end windings is proposed. Then, the average electromagnetic forces acted on the end windings and the relationship between radial and tangential electromagnetic force densities are analyzed. The result shows that the tangential electromagnetic force should be treated as radial one and should not be ignored. Finally, the radial and tangential vibrations are measured to verify the theoretical analysis. The investigation results will be beneficial to the binding and fault diagnosis of stator end windings.
TRANSIENT HEAT CONDUCTION FROM SPHEROIDS
Authors: Alassar Rajai , Abushosha Mohammed , El-Gebeily Mohammed
Published: April 2018

We study the unsteady heat conduction from a spheroid (prolate or oblate) initially heated and then left to cool in an unbounded medium of constant temperature. We present two solutions of the problem. The first makes use of the spheroidal wave functions as basis. The second, which is numerical, is obtained by expanding the dimensionless temperature in terms of Legendre functions and then solving the resulting set of differential equations in the radial direction using an implicit finite difference scheme. The two solutions are further verified by comparing them to the limiting case of a sphere. We study the effect of the axis ratio on the time development of temperature inside the spheroid and the heat flux across the surface.