Transactions of the Canadian Society for Mechanical Engineering
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Volume 37 (2013), Issue 3
Soft food robotic pick and place operation with embedded control structure
Shiuh-Jer Huang, Wei-Han Chang, Janq-Yann Lin
Robotic pick-and-place operation is planned for handling hard objects with on-off control gripper. It does not have force monitoring capability for safe grasping soft objects. Current force/torque sensor is too expensive and difficult to implement. Here, a low cost embedded control structure is designed with distributed FPGA robotic position control and gripper Arduino force control kernels. A model-free intelligent fuzzy sliding mode control strategy is employed to design the position controller of each robotic joint and gripper force controller. Experimental results show that the position and force tracking control errors of this robotic system are less than 1 mm and 0.1 N, respectively for pick-and-place different soft foods.
Aerodynamic performance of an axial compressor with a casing groove combined with injections
Dae-Woong Kim, Jin-Hyuk Kim, Kwang-Yong Kim
Aerodynamic performance of a transonic axial compressor with a casing groove combined with injection has been investigated in this work. Three-dimensional Reynolds-averaged Navier–Stokes equations with k-e turbulence model are discretized by finite volume approximations and solved on hexahedral grids for the flow analyses. For parametric study, the front and rear lengths and height of the casing groove are selected as the geometric parameters and are changed with constant injection to investigate their effects on the stall margin and peak adiabatic efficiency. As a result of the parametric study, the maximum stall margin and peak adiabatic efficiency are found to be obtained in the axial compressor having 70% height of the reference groove. The results show that the application of the casing groove combined with injection to an axial compressor is effective for the simultaneous improvement of both the stall margin and peak adiabatic efficiency of the compressor.
Differential evolution for optimization of PID gain in electrical discharge machining control system
Trias Andromeda, Azli Yahya, Syahrullail Samion, Ameruddin Baharom, Nor Liyana Hashim
PID controller of servo control system maintains the gap between Electrode and workpiece in Electrical Discharge Machining (EDM). Capability of the controller is significant since machining process is a stochastic phenomenon and physical behaviour of the discharge is unpredictable. Therefore, a Proportional Integral Derivative (PID) controller using Differential Evolution (DE) algorithm is designed and applied to an EDM servo actuator system in order to find suitable gain parameters. Simulation results verify the capabilities and effectiveness of the DE algorithm to search the best configuration of PID gain to maintain the electrode position.
Growth characteristics and properties of Al-doped ZnO thin films by DC magnetron sputtering from AZOY® target
Pin-Chuan Yao, Shih-Tse Hang, Menq-Jiun Wu
Transparent conducting Al-doped ZnO (AZO) thin films were deposited on soda-lime glass substrates by DC magnetron sputtering with a novel sintered ceramic target, AZOY® that contains a small amount of Y2O3 in addition to Al2O3 and ZnO. The effect of substrate temperature (Ts) on the structural, electrical and optical properties of the prepared AZO films was evaluated extensively. By elevating Ts, both the electrical conductivity and optical transmittance in the Vis/NIR region of the film could be effectively improved. The substrate heating is closely related to the crystallinity and the surface morphology of the deposited films. It is noteworthy that by employing this target material, high quality AZO thin films could be deposited with a simple and cost effective DC magnetron sputtering system.
Optimization of injection molding parameters for LED lampshade
Kingsun Lee, Jui-Chang Lin
The unibody of LED (light-emitting diodes) lampshades is fabricated by injection mold; the forming technique is complicated, especially for multi-cavity molds. This study applies a finite element analysis to explore the influences of the shrinkage of LED lampshades. The effect of selected injection parameters and their levels on shrinkage size, and the subsequent design of experiments were accomplished using the Taguchi method. The results were confirmed by experiments, which indicated that the selected injection parameters effectively reduce the shrinkage. The error between optimal estimated value and verified value is within 3.82%.
Electromechanical characteristics of polyvinylidene fluoride for flexible electronics
Wen-Yang Chang, Cheng-Hung Hsu
The electromechanical characteristics of PVDF are investigated, including the crystallization, frequency responses, hysteresis, leakage currents, current-voltage characteristics, and fatigue characteristics using Xray 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 adaptive-network-based fuzzy inference system for predicting springback of U-bending
Bor-Tsuen Lin, Kun-Min Huang
Springback will occur when the external force is removed after bending process in sheet metal forming. This paper proposed an adaptive-network-based fuzzy inference system (ANFIS) model for prediction the springback angle of the SPCC material after U-bending. Three parameters were selected as the main factors of affecting the springback after bending, including the die clearance, the punch radius, and the die radius. The training data were obtained from results of U-bending experiment. The training data with four different membership functions – triangular, trapezoidal, bell, and Gaussian functions – were employed in the ANFIS to construct a predictive model for the springback of the U-bending. After the comparison of the predicted value with the checking data, the results show that the triangular membership function has the best accuracy, which make it the best function to predict the springback angle of sheet metals after U-bending.
Genetic-algorithm-based mix proportion design method for recycled aggregate concrete
Several desirable characteristics of concrete, such as strength, slump, durability and low CO2 emission, cannot always be obtained by current conventional mix proportion design methods for recycled aggregate concrete (RAC), because Recycled aggregate generally has lower quality than natural aggregate owing to residual cement paste and various impurities. We treat optimal concrete mix proportioning as a multicriteria problem, and suggest a new method based on genetic algorithms (GAs) to solve the mix proportion design problem for RAC through a simulated biological evolutionary process. In this method, several fitness functions for the desired properties of concrete, i.e., slump, strength, carbonation speed coefficient, price, and emission of CO2, were considered based on conventional data or adopted from previous studies. We thus arrived at optimal mix proportions for RAC that meet the desired performance criteria.
Monitoring and breakthrough control of laser drilled holes by means of machine vision
Chao-Ching Ho, Yuan-Jen Chang, Jin-Chen Hsu, Chia-Lung Kuo, Jun-Jia He
An on-line monitoring system for breakthrough detection in laser drilling is proposed to maximize the material removal rate and energy efficiency of laser through-hole drilling. The system is based on visual monitoring of the working surface using a digital camera, coupled with microcontroller control of the drilling laser operation. The camera is installed adjacent to the entry surface of the workpiece, and the spatial extend of the laser-induced plasma at the working site is monitored radially as the criterion for breakthrough detection. Experimental results show that the proposed system successfully detects when the laser beam has broken through a workpiece, and turns off the laser automatically by feedback control.
The mechanical behaviour of cobalt superalloy with Ti element addition
The influence of titanium element, strain rate and tested temperatures on the mechanical properties and microstructural characteristics will be investigated in this paper. These cobalt-based superalloys are tested using material testing system (MTS) at strain rates of 10-3, 10-2 and 10-1 s-1 and at temperatures of 700, 500 and 25° C, respectively. It is found that the flow stress increases with increasing strain rate and Ti, but decreases with increasing temperature. Furthermore, the strain rate sensitivity increases with increasing strain rate, but decreases with increasing temperature. The microstructural observations confirm that the mechanical response of the cobalt superalloy specimens is directly related to the effects of the titanium contents, strain rate and temperature on the evolution of the microstructure. It can be observed that the strengthening effect in cobalt-based superalloys is a result primarily of dislocation multiplication. The dislocation density increases with increasing strain rate, but decreases with increasing temperature.
Fuzzy simplex-type sliding-mode control
Ta-Tau Chen, Sung-Chun Kuo
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
Yung Hsiang Chen, Tzuu Hseng S. Li, Yung Yue Chen
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
Dongjun Shin, Zhan Fan Quek
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.
Robust adaptive trajectory control for an omnidirectional vehicle with parametric uncertainty
Ya-Chao Yang, Chi-Cheng Cheng
In this paper, a robust adaptive control strategy is proposed for trajectory control of an omnidirectional vehicle with three omni-wheels, which have the ability to move simultaneously with independently rotational motion. The omnidirectional vehicle experiences uncertainties and unknown system parameters. The robust adaptive controller is designed based on the symmetric property of the damping matrix, which allows the matrix can be split into two parts. By the Lyapunov stability, the asymptotic tracking performance can be assured. The proposed control scheme is demonstrated by actual tracking experiments using the omnidirectional vehicle system. Experimental results showed promising tracking performance for the proposed method as compared to traditional sliding mode controller.
Performance analysis of several quasi-orthogonal codes optical CDMA for radio-over-fiber system
Chih-Ta Yen, Ing-Jr Ding, Cheng-Mu Tsai
An optical code-division multiple-access (OCDMA) network for radio-over-fiber (RoF) transmissions was proposed. The network encoders/decoders (codecs) were structured based on arrayed-waveguide-grating (AWG) routers coded using modified prime codes (MPCs). In the proposed system, the lower in-phase cross correlation could reduce the beating noise, and in the proposed study, its performance was compared with that of a conventional system that uses M-sequence and Walsh-Hadamard codes. The performance of both systems was numerically evaluated by analyzing the effect of phase-induced-intensity noise (PIIN). The results showed that the new code families that had lower cross correlation can suppress the intensity of the noise and effectively cancel out the multiple-access interference (MAI) in balanced detection processes, which improved system performance. By using the proposed MPC-coded OCDMA ROF network codecs, each network required only two AWGrouters to accomplish the spectral coding of radio base stations (RBSs) and the decoding of control stations (CSs), resulting in a simple and low-cost system. Therefore, it is possible to produce interference- and crosstalk-free optical CDMA systems for RoF transmissions.
FPGA-based motion controller for wafer-handling robot
Hsin-Hung Chou, Ying-Shieh Kung, Tai-Wei Tsui, Stone Cheng
This study applies FPGA (Field Programmable Gate Arrays) technology to implement a motion controller for wafer-handling robot which has three-DOF (Degree of Freedom) motion. The proposed FPGA-based motion controller has two modules. The first module is Nios II processor which is used to realize the motion trajectory computation and the three-axis position/speed controllers. The second module is demonstrated to implement the three-axis current vector controllers by using FPGA hardware, and VHDL (VHSIC Hardware Description Language) is adopted to describe the controller behavior. Therefore, a fully digital motion controller for wafer-handling robot, such as one trajectory planning, three current vector controllers and three position/speed controllers are all implemented with an FPGA chip.
Design of surface-mounted permanent magnet brushless DC motors combined with gear mechanisms
Yi-Chang Wu, Hong-Sen Yan
This paper presents novel design concepts by integrating surface-mounted permanent-magnet brushless DC (BLDC) motors with embedded planetary gear trains (PGTs) to form compact structure assemblies with desired functions. The operational principles and configurations of surface-mounted permanent-magnet BLDC motors are introduced. With the aid of fundamental circuits, kinematic characteristics of PGTs are identified. For rationalizing integrated design concepts, design requirements and constraints are concluded. Four feasible design concepts with interior and exterior configurations are successfully generated subject to these design requirements and constraints. The features of the integrated devices are also indicated.
Optimization of an ultrathin centrifugal fan based on the Taguchi method with fuzzy logics
Kuang-Hung Hsien, Shyh-Chour Huang
This paper presents the use of fuzzy-based Taguchi method to optimize the design of the ultrathin centrifugal fan with multiple performance characteristics. An orthogonal array, the signal-to-noise (S/N) ratio, multiresponse performance index, analysis of variance (ANOVA), and computational-fluid-dynamics were used to study the multiple-objectives in the ultrathin centrifugal fan design. The design parameters, outlet dimensions, inlet dimensions, blade angle, and impeller diameter were optimized with considerations of the performance characteristics, including volume flow ratio, static pressure, and noise. The results demonstrate that volume flow rate of the new design fan was almost 29% larger than that of the original design. This study also identified the optimized design parameters that affect the cooling performance of the centrifugal fan.
A study of digital watermarking recognition using orthogonal code sequences with a back-propagation neural network
Chih-Ta Yen, Ing-Jr Ding, Zong-Wei Lai
Digital watermarking is an encryption technology commonly used to protect intellectual property and copyright. In this study, we restored watermarks that had already been affected by noise interference, used the Walsh–Hadamard codes as the watermark identification codes, and applied salt-and-pepper noise and Gaussian noise to destroy watermarks. First method, we used a low-pass filter and median filter to remove noise interferences. The second one, we used a back-propagation neural network algorithm to suppress noises. We removed nearly all noise and recovered the originally embedded watermarks of Walsh–Hadmard codes.
Fuzzy logic-based intelligent control for SVM speaker verification with the support of GMM prior information
Ing-Jr Ding, Chih-Ta Yen, Zih-Jheng Lin
In this paper, a fuzzy logic-based intelligent control (FLIC) scheme for support vector machine (SVM) speaker verification, called FLICSVM, is developed. The proposed FLICSVM method enhances SVM training by considering the property of training utterances for establishing the SVM model and therefore could further ensure the robustness of the SVM classifier on speaker verification. In FLICSVM, when establishing the SVM model in the training procedure, the popular fuzzy control methodology is employed to tune certain specific SVM parameter according to the prior information of SVM training utterances that is derived from Gaussian mixture model (GMM) calculations. Experimental results demonstrated that proposed FLICSVM is apparently superior to conventional SVM in the recognition accuracy.
An experimental study on the connection of crossbeams in a modular bridge
Dooyong Cho, WooSeok Kim, Sunkyu Park
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.
The development of motorcycle adaptive rearview system using grey prediction
Yaojung Shiao, Quang-Anh Nguyen, Chun-Fang Hou
The conventional rearview mirrors in a motorcycle are usually fixed, which is easy to cause instant rear blind area for driver on turns or hubbly roads. This study proposes an adaptive rearview mirror system using grey prediction for motorcycle. It can provide up-to-date information and ease to be embedded. According to sensor signals, this system adaptively adjusts the rearview mirrors to compensate the changes of vehicle dynamics in pitching, steering and rolling under different road conditions. A grey predictor was also developed to estimate the change of vehicle dynamics in advance. This system can provide wide and appropriate rear views to the driver to enhance driver’s safety.
Performance analysis of an AKF based tightly-coupled INS/GNSS integrated scheme with NHC for land vehicular applications
Kun-Yao Peng, Cheng-An Lin, Kai-Wei Chiang
INS/GNSS integrated scheme can overcome the shortcoming of INS or GNSS alone to provide superior performance. AKF is based on the maximum likelihood criterion for choosing appropriate weight and thus to adjust factors online. The primary advantage of AKF is that the filter has less relationship with priori statistical information. There are two NHC available for land navigation which the velocity of vehicle in the plane perpendicular to the forward direction is zero. To validate the performance of proposed scheme, the preliminary results illustrated AKF based tightly-coupled INS/GNSS integrated scheme can provide more stable solutions combined with NHC during GNSS outages. Generally speaking, the improvement ratio of 3D positioning reach 40% compared to EKF.
A modified Z-map computational interpolation algorithm for surface machining simulation
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.
Unmanned vehicle obstacle detection and avoidance using danger zone approach
Ta-Chung Wang, Tz-Jian Lin
This paper proposes an obstacle avoidance algorithm for unmanned vehicles in unknown environment. The vehicle uses an ultrasonic sensor and a servo motor which rotates from 0 to 180 degrees to obtain the distance data, and the profile of the obstacle. In this avoidance algorithm we will use the danger zone concept to judge whether the obstacle will cause a possible collision. The danger zone concept surrounds the vehicle through the intersection of semi-algebraic sets. These semi-algebraic sets use the relative velocity of the obstacle to calculate the area in which obstacles will collide with the vehicle within a pre-specified time period. Combining the profile of the boundary of the obstacle with the danger zone concept, a method for determining the safe maneuvers to avoid collisions is also provided.
Development of a laser measurement system for flatness and thickness of the rubber and racket
Yu-Fen Chen, Chien-Hung Liu, Te-Hua Fang
This study analyzes the flatness of the commercial rackets measured by the modified S500 rubber thickness gauge mounted on a moving stage. A least square fitting method was used to calculate the racket flatness of these rackets. The experimental results showed the average flatness of all samples is 0.03 mm and the triple standard deviation is ±0.03 mm. The flatness of the rackets will lead to an in accurate examination of the rubber thickness before a match.
Robust finite time controller design for second order nonlinear underactuated mechanical systems
Chi-Cheng Cheng, Kuang-Shine Yang, Jung-Hua Yang
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.
Passivity-based parameter estimation and composite adaptive position control of induction motors
In the rotor reference frame, the input-output linearization theory was adopted to decouple the rotor position and rotor flux. We then designed two adaptation laws to estimate the rotor resistance and mechanical parameters of the motor. The passive properties of the negative feedback connection from the rotor flux observer to the rotor resistance estimator, and the position controller were analyzed according to the passivity theorem. The overall control system was proved to be globally stable. Finally, experimental results show that the proposed scheme is robust to the variations of the rotor resistance and load torque disturbances. Furthermore, the estimated parameters can converge to the actual values.
Force and position control of the pneumatic cylinders through a microscope with a CCD camera
Chen Hung I, Shih Ming Chang
In this paper, the pneumatic driven manipulation system is driven by the pneumatic cylinders. The proposed system is built by the designed pneumatic force control system and the microscope, which are integrated with the control interface. Visual C++ code from MFC is used to finish the control interface. A self tuning fuzzy controller with a dead zone compensator is designed to improve the force precision of the proposed system. From experimental results, the force error can be controlled within ±1 mN and the position error can be stayed within ±1 pixel using the visual servo.
Robust control for a pneumatic muscle actuator system
Liu-Hsu Lin, Jia-Yush Yen, Fu-Cheng Wang
This paper presents the modeling and robust control of a pneumatic muscle actuator system. Due to the inherent nonlinear and time-varying characteristics of this system, it is difficult to achieve excellent performance using conventional control methods. Therefore, we apply identification techniques to model the system as linear transfer functions and regard the un-modeled dynamics as system uncertainties. Because H∞ robust control is well-known for its capability in dealing with system uncertainties, we then apply H∞ robust control strategies to guarantee system stability and performance for the system. From the experimental results, the proposed H∞ robust controller is deemed effective.
Adaptive iterative learning control of robotic systems using backstepping design
Ying-Chung Wang, Chiang-Ju Chien, Chi-Nan Chuang
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.
Construction of an elementary model for the dynamic analysis of a pressurized water reactor
Chiung-Wen Tsai, Chunkuan Shih, Jong-Rong Wang
A lumped-parameter numerical model was constructed based on the conservation laws of mass and energy and the point neutron kinetics with 6 groups of delayed neutron to represent the dynamics of a pressurized water reactor core. On the viewpoint of control theory, the coupled phenomenon of neutron kinetics and thermal-hydraulics can be recognized as a dynamic system with feedback loops by the Doppler effect and the coolant temperature. Scilab was implemented to construct the equivalent transfer functions and associated feedback loops of a PWR core. The dynamic responses were performed by the perturbations of positive reactivity insertion, coolant flow rate, and coolant inlet temperature. This elementary PWR core model has been qualitatively assessed against independent numerical data to ensure the models and codes have a certain level of confidence or validation.
Improving eigenspace-based fuzzy logic system using a linear interpolation scheme for speech pattern recognition
Ing-Jr Ding, Chih-Ta Yen
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.
Evaluation of analytical and finite element modeling on piezo-electric cantilever bimorph energy harvester
Long Zhang, Keith A. Williams, Zhengchao Xie
Harvesting the electrical energy from their working environment has become a feasible choice of realizing self-powered systems or providing supplementary power sources to the battery. In this paper, a pre-loaded piezoelectric cantilever bimorph (PCB) energy harvester is adopted as the research object, for which a single degree-of-freedom analytical model and finite element modeling have been carried out to study its dynamic responses. The laboratory experiments have also been performed to validate the analytical and the finite element modeling. It shows that finite element modeling has a better agreement with the experimental results than the analytical model, while the latter has a rough accuracy and can be used to obtain quick estimations of the dynamic response of the PCB energy harvester in certain cases.
Liquid-liquid mixtures flow in microchannels
This study constitutes an experimental and numerical investigation into the single-phase flow of liquid–liquid mixtures and of water in uniform, converging and diverging microchannels. The experimental results for the pressure drop in three microchannels show good agreement with both theoretical predictions and CFD simulation results. The numerical velocity profiles in microchannels are also presented and show excellent agreement with the analytical velocity profiles. In addition, the pressure distribution prediction for the converging and diverging microchannels is also consistent with that obtained through the CFD results.
A study on the engine compartment airflow of a light aircraft using computational fluid dynamics
Hsu-jeng Liu, Chih-chun Su, Sheng-liang Huang
This study applies FLUENT to simulate and analyze the flow characteristics in the engine compartment of a light aircraft. The air inlet, air duct, guide vane, and air outlet are designed to improve the flow conditions according to the drawbacks of the prototype model. The results show that the air duct and guide vane lead the airflow to the certain position of cylinders, and the air outlet reduces the pressure in the engine compartment. Moreover, combining these designs significantly increases the overall airflow velocity in the engine compartment.
A microfluidic device integrated active cooling channel for DNA amplification
Jyh Jian Chen, Xian Cheng Qiu, Chia Ming Shen, Sin Jhih Chen, Yu Wei Ko
This paper presents a novel flow-through polymerase chain reaction (PCR) chip with active water cooling characteristics. A micro-reactor comprising two heating blocks and a cooling channel for three temperature zones and a fluidic chip with serpentine microchannels is integrated. One important feature of this system is the temperature of the annealing zone is controlled by the flow rate of the fluid inside a water cooling channel under the glass chip. Commercial software is utilized to determine the chip materials and flow rates in the cooling channel those are responsible for creating the denaturation, annealing and extension temperature zones within the chip. DNA fragments with three different lengths are successfully amplified with the device.
Gear fault diagnosis in time domains via Bayesian networks
Chun-Chieh Wang, Yuan Kang, Chin-Chi Liao
In gear or rolling bearing systems, it is difficult to extract symptoms from vibration signals where shock vibration signals are present. However, the neural network method cannot provide satisfactory diagnosis results without adequate training samples. Bayesian networks provide an effective approach for fault diagnosis in cases given uncertain and incomplete information. In this study, the statistical factors of vibration signals in the time-domain were used and the diagnosis results by using Bayesian networks were superior to other neural network methods.
Passivity-based integral control and stability analysis of a constrained single-link flexible arm
Liang Y. Liu, Hsiung C. Lin
The design of flexible manipulator is complicated due to inherently infinite dimension in nature. The sequential challenge is the problem such a non-minimum phase that is the cause of system instability. In this paper, a constrained single-link flexible arm is fully investigated using a linear distributed parameter model. In order to overcome the inherent limitations, a new input induced by the joint angular acceleration and an output generated using the contact force and root shear force are defined. A necessary and sufficient condition is thus derived so that all poles and zeros of the new transfer function lie on the imaginary axis. Also, the passive integral control is designed to accomplish the regulation of the contact force. The excellent performance of the passive integral controller is verified through numerical simulations.
On the design of new programmable exact path generators
A design method of new programmable exact path generators is proposed. The instantaneous positions of the linear input link corresponding to current angular positions of the rotational input link for each point of exact paths are also derived. By controlling the instantaneous position of linear and rotational input link, the required exact paths can be generated during a cycle. This design approach makes the proposed linkage mechanism programmable and adjustable, and increases their flexibility in practical applications.
Experimental analysis of mixed convection heat transfer on heat sink of LED lamp
Sheng-Chung Tzeng, Tzer-Ming Jeng
The device made of fan and pin-fin heat sink should be a powerful heat sink for LED lamp. This study used transient liquid crystal experimentation to measure the end-wall heat transfer coefficient of linearly arrayed square pin array in the rectangular channel, and discussed the influence of longitudinal spacing on heat transfer. The relative transverse spacing (XT = ST/d) was set as 3, and the relative longitudinal spacing (XL = SL/d = 1.88–5) and the Reynolds number (Re = 11047–17937) were changed. Considering the endwall area, the average Nusselt number with square pin was 1.46–2.58 times of that without square pin, and the square pin array of XT = 3.75 had the maximum end-wall heat transfer gain.
Simulation of workpiece deformation caused by releasing the clamping force
Xiao-Dong Shao, Si-Meng Liu, Liu Zhang, Zhao-Xu Lin
A novel algorithm to predict machining error caused by releasing the clamping force is put forward in this paper. First, the deformity of the workpiece by clamping force is calculated using FEM. Then the relaxing deformity of the workpiece caused by releasing the clamping force is calculated by the mapping method based on mesh model. The machining error is achieved using error analysis technology. A test is conducted to verify the performance of the simulation result.
Structural synthesis of novel basic two-DOF differentials
Differentials are very important in many crucial applications, but almost all differentials are geared differential mechanisms. Therefore, the main purpose of this paper is to synthesize non-gear or novel differentials. All kinds of basic differentials can be contained in the results by the method. First, a modified graph representation is provided for differential mechanisms with different type. Second, the design concept of composition and decomposition the geometric constraint is presented. Then, ten fundamental entities and seven properties of differentials are collated. Finally, eight feasible results with two degrees-of-freedom and two basic loops are obtained. About the eight results, there are two are existing designs and the other six are novel.
A novel design of semi-active suspension system using magneto rheological damper on light-weight vehicle
Yaojung Shiao, Quang-Anh Nguyen, Chun-Chi Lai
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 study on thermal initial properties for inverse technique
Sung-Deok Hong, Chan-Soo Kim, Migyung Cho, Cheolho Bai, Sung-Yull Hong, Jaesool Shim
The Levenberg–Marguardt algorithm is used to study on convergence for inverse heat conduction in the unsteady state. In this model, the finite volume method is used to obtain an estimated temperature, which is necessary for minimizing inverse error. Six simulations were performed to investigate the sensitivity to initial thermo-physical properties such as thermal conductivity (k) and heat capacity (ρCp ≡ C) by changing three different damping ratios of the Levenberg–Marquardt algorithm. Our results show that an appropriate selection of thermal-physical properties and damping ratio helps numerical stability and convergence and reduces convergence time.
The innovative design of automatic transmission for electric motorcycles
Long-Chang Hsieh, Hsiu-Chen Tang
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.
Combined temperature and moisture effect on the strength of carbon nanotube reinforced epoxy materials
Yi-Ming Jen, Chien-Yang Huang
This study experimentally analyzed the hygrothermal effect on the static and fatigue strengths of multiwalled carbon nanotubes (CNTs)/epoxy composites. The results show that the static and fatigue strengths decreased slightly at 25°C/85% RH environments compared with those tested under the 25°C/60% RH condition. However, the strengths decreased substantially under the 40°C/85% RH condition, indicating that the combined temperature and humidity environments weaken the interfacial adhesion between the CNT surfaces and the epoxy matrix.
The influence on the thermal resistance of LED packaging with different submount and surrounding conditions
Farn-Shiun Hwu, Ho-Chih Cheng, Ya-Hui Hu, Gwo-Jiun Sheu
A three-dimensional numerical model using the finite element method is proposed in the present study to accurately simulate the influences of the thermal resistance on the submount of an LED. In a system with adiabatic lateral boundaries, the internal thermal resistance of the submount is principally analyzed from the series connection effect of the spreading thermal resistance and one-dimensional material resistance. However, the total thermal resistance is used for analysis under various heat dissipating conditions due to the complex coupling relations among the material resistance, the spreading thermal resistance, and the external thermal resistance. A higher contact ratio between heat source and submount, a larger external convective effect, and dissipation of heat from the symmetrical axis of the submount will decrease the spreading thermal resistance.
Application of homogenous transformation matrix to the modeling of a ball-end cutter
This paper presents a comprehensive and straightforward method for the mathematical modeling of a generic ball-end cutter. In the proposed approach, a mathematical model of the rake surface is developed based on a normal helix cutting edge geometric model. A mathematical model of the flank surface is then derived based on the assumption of a constant clearance angle. The proposed model is applicable to a wide range of ball-end cutters. As a result, it provides an ideal basis for the generation of the NC equations required to machine ball-end cutters on a 6-axis CNC grinding machine.
A new electromagnetic valve train with PM/EM actuator in SI engines
Yaojung Shiao, Ly Vinh Dat
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.
Multi-objective optimal mechanical power for turbine of river current power generation using fuzzy dominant directed-graph method
Jian-Long Kuo, Kai-Lun Chao
The fuzzy dominant directed graph (fuzzy DDG) method is proposed in this paper to realize the multiobjective optimal mechanical turbine power of a river current (RC) power generation system. The testing case illustrates the problem with vertex S/N ratio values included. Fuzzy potential values are derived. The experimental results are provided to verify the validity of the fuzzy-DDG method. It is clear that this method is applicable; it easily and quickly finds the optimal solution.
Hydrostatic mechanism of a wavy-tilt-dam mechanical seal
"Wei Liu, Ying Liu, Jingjing Zhai, Weifeng Huang, Yuming Wang"
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.
Sum of sinusoidal plus noise model to extract component error from a double ballbar measurement error map
Agung-Shamsuddin Saragih, Tae-Jo Ko
The double ballbar (DBB) test, which captures actual data from multiple error origins of axes interaction, was defined as sinusoid error map model plus noise. When the number of sinusoids is the same as the number of individual errors of moving axis in the test map, we can extract a single source geometric error value from the DBB error map by modeling the well-known geometric error of linear axis. We considered the "noise" as mixed errors from other sources than geometric errors. This method is applicable to both a full circle and a truncated DBB test path.
Study of a new and low-cost measurement method of volumetric errors for CNC five-axis machine tools
Shih-Ming Wang, Han-Jen Yu, Hung-Wei Liao
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
Tzer-Ming Jeng, Sheng-Chung Tzeng, Zhi-Ting Yeh
This study experimentally investigated the free convection heat transfer characteristics of the annular metalfoam 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.
Analysis of NO formation in counter-flow premixed hydrogen-air flame
Tianfang Xie and Peiyong Wang
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.
Mechanical behavior of copper thin films subjected to various strain rate loadings
Kuan-Jung Chung, Chi-Feng Lin and Wei-Cheng Chiang
In this study, a micro-force tensile testing machine (MTS Tytron 250) was applied to test the polyimide samples coated with different thicknesses of copper (500–1500 nm). The experiments using different strain rates (1.6 ×10-4 to 1.6 ×10-2 s-1) were conducted to the test vehicles. The results showed that the stress and strain of Cu films were strongly correlated with the strain rate and film thickness. The mechanical strength, yield stress, Young’s modulus, and maximum tensile stress, increase as the strain rate increases or the thickness decreases. Strain rate sensitivity rapidly increases as the thickness decreases from 750 to 500 nm to imply that the workhardening rate increases while the thickness decreases, resulting in a higher probability of brittle failure.
Ink jet printed thin films on glass and polyimide substrates
Tsai-Cheng Li, Rwei-Ching Chang, Yen-Choung Li
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.
Technical development of heat energy recovery for vehicle power system
Tzer-Ming Jeng, Sheng-Chung Tzeng
A Toyota 2200 c.c. vehicle with four-cylinder four-cycle engine was used for real vehicle test to discuss the influence of the vehicle’s engine speed and external cooling air flow on the energy output of the waste heat recovering thermoelectric conversion system. This study found that the energy output increased with the engine speed. However, if the engine speed was too high (exceeding 2500 rpm), the thermoelectric generator would be overheated and damaged. Besides, there was an optimal external cooling air flow to generate the maximum energy output.
Thermal performance of vertical heat sinks with different piezofan arrangements
Jin-Cherng Shyu, Jhih-Zong Syu
This study examines various effects on the heat transfer enhancement of several vertical heat sinks with a running piezofan. Both plate-fin heat sink and pin-fin heat sink having a 10-mm-high or 30-mm-high fin array were tested with either a vertical or a horizontal piezofan. Results show that the piezofan tip located at x/L = 0.5 usually yielded the highest heat transfer enhancement. Besides, heat transfer enhancement factors ranged from 1.2 to 2.4 for the present 10-mm-high plate-fin heat sink, and from 1.1 to 2.6 for the 10-mm-high pin-fin heat sink.
On the design and analysis of acoustic horns for ultrasonic welding
Kuen-Ming Shu, Wen-Hsiang Hsieh, Hoa-Shen Yen
The acoustic horn plays a very vital part in high energy ultrasonic machining, and its design is critical to the quality and the efficiency of machining. This paper performs the analysis and design of acoustic horns for ultrasonic machining by employing ANSYS finite element software. The results indicate that not only the natural frequencies of horns designed by theoretical models are more close to the vibration frequencies of ultrasonic generators, but also their amplitudes are superior to commercially available horns.
Prediction of fluid flow and heat transfer through square duct with twisted tape insert and interrupted rib
Ho Keun Kang, Soo Whan Ahn, Myung Sung Lee, Dae Hee Lee
Numerical predictions of characteristics of turbulent flows through a square duct (30 × 30 mm) with twisted tape inserts and with twisted tape inserts plus interrupted ribs are conducted to investigate regionally averaged heat transfer and friction factors. The twisted tape is a 0.1 mm thick carbon steel sheet with a diameter of 28 mm, length of 900 mm and 2.5 turns. The present study demonstrates that the twisted tape with interrupted ribs provides a greater overall heat transfer performance over the twisted tape with no ribs in the square duct.
Atomistic scale simultion of textured surfaces on dry sliding friction
Ming-Yuan Chen, Zheng-Han Hong, Te-Hua Fang, Shao-Hui Kang, Li-Min Kuo
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.
GA based hybrid fuzzy rule optimization approach for elevator group control system
Ta-Cheng Chen, Yuan-Yong Hsu, An-Chen Lee, Shiang-Yu Wang
Elevators are the essential transportation tools in high buildings so that elevator group control system (EGCS) is developed to dynamically layout the schedule of elevators in a group. In this study, a fuzzy rule based intelligent EGCS optimized by genetic algorithm has been proposed where the rules with the corresponding parameters are generated optimally so as to maximize service quality. The experimental results show that the performance of our approach is superior to these of traditional approaches in the literature.
On the symbolized representation of innovative bicycle with functional elements characteristics for creative design
Nien-Te Liu, Chang-Tzuoh Wu
This paper proposes representations for bicycles. Innovative bicycles are analyzed and arranged one by one to find functional elements of creative characteristics. The elements of bicycles can be classified into three kinds: functional elements, form elements, and material elements. For the functional elements, they are classified into 14 kinds, where controlling, moving, and input elements are necessary for bicycles. By using symbols, bicycles can be represented simply and quickly for innovation design.
Automatic design of shift-and-add based color space converter using genetic algorithm
Ching-Yi Chen, Ching-Han Chen, Chih-Hao Ma, Po-Yi Wu
The main purpose of this paper is to investigate a novel design method using a genetic algorithm (GA) to automatically evolve the multiplierless CSC circuit architecture. In order to demonstrate the effectiveness of the described design method, several test images are adopted respectively to perform RGB to YCbCr color conversion experiment. The experimental results represent that the performance of the implemented hardware architecture is good when carrying out color space conversion from RGB to YCbCr. It also has the advantage of being high-speed, low-complexity, and low-area.
Missile guidance algorithm design using particle swarm optimization
Chien-Chun Kung, Kuei-Yi Chen
This paper presents a PSO guidance (PSOG) algorithm design for the pursuit-evasion optimization problem. The initialized particles are randomly set within the guidance command solution space and the relative distance is taken as the objective function. As the PSOG algorithm proceeds, the iteration will execute until the global optimum is reached. Two pursuit-evasion scenarios show that the PSOG algorithm has satisfied performance in execution time, terminal miss distance, time of interception, final stage turning rate and robust pursuit capability.
Cloud computing based intelligent manufacturing scheduling system using the quality prediction method
Chung-Lin Huang, Chung-Chi Huang
This paper proposes the development of a cloud computing based intelligent manufacturing scheduling system (CBIMS) using the quality prediction method. A CBIMS continuously builds up many different production line layout modes. We use the cloud database for scattering and storing data, and the scheduling engine contains a sequence score system of products, an optimized layout system, and a monitoring system for all available resources. The results show the advantages, including low cost, good quality, production fluency, and flexible management.
An interactive nanomanipulation visualization based on molecular dynamics simulation and virtual reality
Chun-Ta Chen, Shin-Yong Chen, Chien-Hsiang Liao, Shi-Chang Zeng
In this paper, an interactive virtual environment for nanomanipulation is developed. The technique for nanomanipulation visualization is based on molecular dynamics simulation and virtual reality. Using the developed interactive virtual environment for the intuitive nanomanipulation visualization, the operator can characterize and control the behavior of nanoparticles in the virtual SPM through physical simulation and 3D visualization.
Experimental investigations of MPPT in a small scale photovoltaic energy system based on extremum seeking control
Her-Terng Yau, Chen-Han Wu
This study carried out experimental validation based on the simulation analysis results of Yau and Wu , 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
Yi-Ming Lee, Kuei-Shu Hsu, Shyue-Bin Chang
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
Ming-Shium Hsieh, Chin-Sheng Chen, Kuan-Sheng Chien
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.
Synchronous measurements of finger surface temperature from three different kinds of temperature sensors
Fong-Lin Jang, Chyun-Chau Lin
The aim of this study was to explore new valid sensors for temperature biofeedback. Three kinds of temperature sensors (thermography imaging, thermistor, and infrared thermopile) were employed to record participants’ finger surface temperatures simultaneously. The skin temperature readings resulted in strong correlations between sensors. These results suggested that contact and non-contact temperature sensors all had good synchronous temperature covariance in measuring finger surface temperature.
Full journal title: Transactions of the Canadian Society for Mechanical Engineering
Abreviated journal title: Trans. Can. Soc. Mech. Eng.
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