bluuebunny/crossref_metadata_2025 huggingface dataset:
PREDICTING AND REDUCING GLAZE ICE ACCRETION ON ELECTRIC POWER LINES WITH JOULE HEATING: THEORY AND EXPERIMENTS
Authors: Naterer G.F. , Deng H. , Popplewell N.
Published: April 2018

An analytical model is developed for the prediction of glaze ice accretion with runback water for electric power lines including the Joule heating effect. In this model, the external air flow is coupled with the liquid film flow by slip (non-zero velocity) boundary conditions a the liquid-air interface. In this way, corrections to previous rime ice models are given in order to account for runback water and its effect on wet ice growth in freezing rain conditions with ambient temperatures slightly below 0[°C]. Also, the process of Joule heating in icing conditions is examined from a thermodynamic optimization viewpoint in a manner which permits efficient power transmission while dissipating heat in order to reduce ice accumulation. Good agreement is achieved between theoretical predictions of the glaze ice accretion and experimental results from the freezing rain simulator at the University of Manitoba.
THE CHARACTERISTICS OF A HEAT-RECIRCULATING CERAMIC BURNER
Authors: Arai N. , Shinoda M. , Churchill S.W.
Published: April 2018

An experimental burner of the heat-recirculating type was constructed and its thermal characteristics were investigated for methane-air fuel-lean combustion. Longitudinal temperature distributions of air and burned gas flowing in the passes of the burner were determined by means of both experimental measurements and numerical simulations. Using the heat recirculation rate and the thermal efficiency as criteria for the heat transfer performance of the burner, the optimal design of the burner was examined in terms of a chemical parameter (the equivalence ratio), a fluid-mechanical parameter (the Reynolds number), and two geometrical parameters (the aspect ratio and the number of passes).
EXERGY ANALYSIS OF THE ENVIRONMENTAL IMPACT OF PAVING MATERIAL MANUFACTURE
Authors: Berthiaume R. , Bouchard C.
Published: April 2018

Exergy analysis permits accurate measurement of the degradation of matter and energy using a single concept. A macroscopic exergy accounting method is proposed and applied to assess the environmental impact of road covering material manufacturing. Cement concrete and asphalt covers are examined. From the manufacturing process mass balances and exergy analyses conducted primarily by Szargut and his co-workers, the net exergy consumption for each type of paving material is calculated. This exergy consumption broadly reflects the minimum work required to reform the raw materials and restore the environment to its initial state. This minimum work may serve as a thermodynamic measure of the environmental impact of an entire manufacturing process, from the resource drawn from the environment to the finished product. In the two cases under study, the environmental impact depends on the type, thickness and manufacturing process of the paving material. An older technology, such as the manufacture of cement concrete using the wet process, appears disadvantageous, as is the production of asphalt cover which is manufactured during the fall. The proposed exergy indicator permits ranking of the materials according to their overall long-term impact on the environment.
TECHNO-ECONOMIC ANALYSIS OF IGCC POWER GENERATION SYSTEMS BASED ON FLUIDIZED BED GASIFIERS
Authors: Ong’iro A. , Ugursal V.I. , Al Taweel A.M.
Published: April 2018

A computerized techno-economic model that can be used to predict the thermal, environmental and economic aspects of integrated gasification combined cycles (IGCC) using fluidized bed gasifiers was developed. A brief description of the model is presented and representative applications of the model are demonstrated with a case study. The results verify the favourable characteristics of IGCC systems (i.e. high thermal efficiency, low levelized unit electricity cost, and reduced pollution emissions) and illustrate the effect of various parameters on the performance of IGCC power plants. Models for IGCC with moving bed and entrained bed gasifiers are presented elsewhere.
DESIGN AND ANALYSIS OF A FACILITY FOR FREE – FLOATING FLEXIBLE ROBOTIC MANIPULATORS
Authors: Lovekin D. , Heppler G.R. , McPhee J.
Published: April 2018

The development of the Waterloo Flexible Link Experimental (WATFLEX) facility was initiated at the University of Waterloo to provide resources for conducting experiments involving the dynamics and control of flexible robotic manipulators – specifically, two dimensional dynamic mass capture, impact dynamics and vibration suppression. The system consists of a number of different subsystems including the robotic manipulator, motion and deflection sensors, the digital controller, the data acquisition system, and the pneumatic system that floats the manipulator on a support structure. In this paper, the design and current status of each of these subsystems is described. Experimental analysis results of the support table, the data acquisition system, and some analog sensors are presented and analyzed.
CONSTRUCTION OF SCREW GEOMETRY VIA 3-D CAD SYSTEM FOR THE ANALYSIS AND SYNTHESIS OF SPATIAL MECHANISMS
Authors: Chen F.Z. , Tsai M.J.
Published: April 2018

This paper investigates the application of computer-aided design and drawing (CAD) software to the kinematic analysis and synthesis of spatial mechanisms based upon screw geometry. The advantages of the graphic method for the synthesis and analysis of mechanisms are straightforward, comprehensive, clearly represented, and easy to correlate to a real mechanism. Using conventional 3-D CAD software, the screw axes and joint axes are constructed as virtual parts. The relationships of joint axes that are constrained by screw geometry are the assembly conditions for the virtual parts in the CAD system. This paper shows that, similar to the synthesis of a planar linkage, the synthesis of a spatial C-C dyad by the graphical method in a CAD system is an efficient process.
APPLYING TWO-PARAMETER ENVELOPE THEORY TO DETERMINING SPHERICAL CAM PROFILE WITH CYLINDERICAL FOLLOWERS
Authors: Yang Shyue-Cheng , Chen Cha’o-Kuang
Published: April 2018

Using the envelope theory of two-parameter family of ball surfaces, two geometric models of spherical cam can be easily obtained when the follower-motion program has been given. The results of the envelope theory are used to determine an optimal spherical cam profile with an oscillating cylindrical follower. Some investigations of geometric characteristic, such as pressure angle and cutting path, are determined using the obtained geometric model. The principle curvatures are analyzed to avoid undercutting. Finally, a numerical example is given to illustrate the application of the procedure.
THE BAUSCHINGER AND HARDENING EFFECT ON RESIDUAL STRESSES IN THICK-WALLED CYLINDERS OF SUS 304
Authors: Ghorbanpour A. , Loghman A. , Khademizadeh H. , Moradi M.
Published: April 2018

A thick-walled cylinder of strain hardening material with closed ends, which is assumed to obey Von-Mises yield criterion is considered. An elastoplastic and residual stress analysis of thick-walled cylinders is performed with the incremental theory of plasticity. Critical pressures of direct and reverse yielding are investigated using the Von-Mises yield criterion as well as the Bauschinger effect factor (BEF). The material selected is SUS 304 stainless steel. The material's loading and unloading properties including the (BEF) are obtained experimentally and represented mathematically as a continuous function of effective plastic strain. The material model and the BEF have been incorporated in an analytical-numerical model so as to predict the cylinders plastic and residual stresses as well as the critical pressures of direct and reverse yielding. The analytical-numerical model for the prediction of critical inner pressure, plastic stress distributions and the subsequent residual stresses of thick-walled cylinders is validated by using experimental results. Residual stresses with and without the BEF are obtained and the corresponding results are compared. In the case study of a specific cylinder (Radii ratio of β=2), it has been concluded that residual stresses subsequent to a 45% overstrained condition are at the onset of reverse yielding when the BEF is considered.
ULTRASONIC IMAGING OF MATERIAL CONDITION USING ADVANCED SIMPLIFIED ULTRASONIC CT
Authors: Kim Kyung Cho , Fukuhara Hiroaki , Yamawaki Hisashi
Published: April 2018

In this research, a new measurement method to estimate on infinitesimal change in material condition, the simplified ultrasonic CT system, which uses the information of three directions, that is, 90°, +45° and -45° to the inspection plane is proposed. The use of a simplified ultrasonic CT system has two merits: firstly, the measurement time is very short compared to a general CT; secondly, it can detect sensitively very infinitesimal defects in vertical or slant directions about the inspection plane because the obtained image is not a C scan image but a CT image calculated from three directions. Because of these merits, this method can be considered very effective for the evaluation of material condition. In order to know the applicability of actual NDT, several kinds of welded specimens were investigated. The results showed that the CT images obtained were very similar to the actual defect of specimens. Also, in order to confirm the performance of simplified ultrasonic CT, the D scan image by the TOFD method was obtained for the same specimen. The C scan or CT image gave better information than the D scan image obtained from TOFD method. In this research, the frequency analysis method for enhancing the C scan or CT image is developed. This frequency analysis method is based on the frequency response property of the material. By comparing the magnitude at frequency domain, the special frequency which shows the greatest difference between welded joint and base material was searched for and used to get a C scan or CT image.
TRADEOFF COORDINATION AND ITS AUTOMATION IN ROBUST DESIGN
Authors: Chen Li
Published: April 2018

A formal coordination-based method is presented to systematically deal with the subjective tradeoff between “performance precision” and “performance accuracy” in robust design, where the coordination of tradeoff is treated as analogous to the control of a physical process. A two-objective optimization model that minimizes design variability and maximizes design functionality is formulated to characterize design robustness. By treating coordination as a control process, a fuzzy control approach is suggested to express and configure the coordination mechanism based on fuzzy logic by which design tradeoffs can be automatically coordinated via fuzzy control rules. To underlie the coordination-based method, three design models are derived with respect to three design schemes in robust design. By adjusting a design control parameter, these models enable one to obtain alternate Pareto-optimal design solutions. Based on the fuzzy control rules (also serving as a “design super-criterion”), design coordination can be governed toward the most desirable robust design in the Pareto-optimal solution domain. A welded beam design example is implemented to illustrate validity and applicability of the method.
OBJECT SHAPE EXPLORATION AND RECOGNITION IN 2D USING A TWO-FINGERED ROBOTIC HAND
Authors: Du Yonghui , Bone Gary M.
Published: April 2018

Exploration with a robotic hand is a method for measuring the shape and location of objects. This information may be used to recognize the object from a given set, or to generate a model of the object. A novel two-dimensional exploration method employing multiple wrapping grasps without tactile sensors is presented. An object shape model is produced from the finger position information. An efficient procedure for recognizing the object from a given reference set is presented. Experiments are conducted with a two-fingered robotic hand with five degrees-of-freedom. Objects with circular, square and triangular cross-sections are explored, modeled and recognized using as few as six grasps.
SENSOR BASED ROBOT LOCALISATION AND NAVIGATION: USING INTERVAL ANALYSIS AND NONLINEAR KALMAN FILTERS.
Authors: Ashokaraj Immanuel , Tsourdos Antonios , Silson Peter , White Brian
Published: April 2018

Multiple sensor fusion for robot localisation and navigation has attracted a lot of interest in recent years. This paper describes a sensor based navigation and localisation approach for an autonomous mobile robot using an interval analysis (IA) based adaptive mechanism for the non-linear Kalman filter namely the Extended Kalman filter (EKF). The map used for this study is two-dimensional and assumed to be known a priori. The robot is equipped with inertial sensors (INS), encoders and ultrasonic sensors. A non-linear Kalman filter is used to estimate the robots position using the inertial sensors and encoders. The ultrasonic sensors use an Interval Analysis (IA) algorithm for guaranteed robot localisation. Since the Kalman Filter estimates may be affected by bias, drift etc. we propose an adaptive mechanism using IA to correct these defects in estimates. In the presence of landmarks the complementary interval robot position information from the IA algorithm with uniform distribution using ultrasonic sensors is used to estimate and bound the errors in the non-linear Kalman filter robot position estimate with a Gaussian distribution.
FORCE-UNCONSTRAINED POSES FOR PARALLEL MANIPULATORS WITH REDUNDANT ACTUATED BRANCHES
Authors: Firmani Flavio , Podhorodeski Ron P.
Published: April 2018

A study of the effect of including a redundant actuated branch on the existence of force-unconstrained configurations for a planar parallel layout of joints is presented1. Two methodologies for finding the force-unconstrained poses are described and discussed. The first method involves the differentiation of the nonlinear kinematic constraints of the input and output variables with respect to time. The second method makes use of the reciprocal screws associated with the actuated joints. The force-unconstrained poses of non-redundantly actuated planar parallel manipulators can be mathematically expressed by means of a polynomial in terms of the three variables that define the dimensional space of the planar manipulator, i.e., the location and orientation of the end-effector. The inclusion of redundant actuated branches leads to a system of polynomials, i.e., one additional polynomial for each redundant branch added. Elimination methods are employed to reduce the number of variables by one for every additional polynomial. This leads to a higher order polynomial with fewer variables. The roots of the resulting polynomial describe the force-unconstrained poses of the manipulator. For planar manipulators it is shown that one order of infinity of force-unconstrained configurations is eliminated for every actuated branch, beyond three, added. As an example, the four-branch revolute-prismatic-revolute mechanism (4-RPR), where the prismatic joints are actuated, is presented.
A COMPARISON OF THE EFFECTIVENESS OF DOUBLE- AND SINGLE-GIMBALED CONTROL MOMENT GYROSCOPES FOR VIBRATION SUPPRESSION
Authors: Muise Aaron , Bauer Robert J.
Published: April 2018

Control Moment Gyroscopes (CMGs) have typically been used for attitude control of satellites. This paper extends the application of CMGs to regulate vibrations in the flexible appendages of orbiting spacecraft using a novel double- and single-gimbaled CMG prototype design. System Identification and control experiments were carried out to compare the effectiveness of this new CMG to regulate lightly damped, low frequency vibrations in a single flexible rib. Experimental results conclude that the CMG can be effectively used to regulate vibrations in flexible structures and, for equivalent values of gyricity and disturbance, the double-gimbaled CMG performance can be two to three times more effective and independent of the direction of applied disturbance.
DYNAMIC SIMULATION OF A SPATIAL 3-DOF TENSEGRITY MECHANISM
Authors: Arsenault Marc , Gosselin Clément M.
Published: April 2018

Tensegrity mechanisms have the advantage of being relatively lightweight due to. their extensive use of cables and springs. As such, they have the potential of being an attractive alternative to conventional mechanisms in certain application environments. However, the presence of unconstrained degrees of freedom in tensegrity mechanisms leads to a dynamic behaviour that cannot be directly controlled with the actuators. In this work, the dynamic model of a novel spatial three-degree-of-freedom (3-DOF) tensegrity mechanism is developed using the Lagrangian formulation. The resulting equations of motion are then solved to simulate the mechanism's motion between equilibrium configurations. Since the mechanism is subjected to holonomic nonlinear geometrical constraints, these must be considered during the solution of its forward dynamic problem. It is seen that the use of damping in the springs is not very efficient in dissipating the mechanism's energy during motion.
SYSTEMATIC ADAPTIVE FUZZY LOGIC MODELLING OF COMPLEX SYSTEMS FROM INPUT-OUTPUT DATA
Authors: Zeinali Meysar , Notash Leila
Published: April 2018

The complex nonlinear systems, which are difficult to be mathematically modelled, can be described by a fuzzy model. This article attempts to improve and to address the problems concerning the systematic fuzzy-logic modelling of multi-input-muiti-output (MIMO) systems, by introducing the following three concepts. 1) A generalized and parameterized reasoning mechanism constructed based on the weighted sum of the normalized defuzzified output value of each individual rule. Then the crisp outputs of the fuzzy model can be directly calculated from the crisp inputs using the parameterized reasoning mechanism. This reasoning mechanism is suitable for online learning and real-time control applications. 2) A gradient-descent based parameter adjustment to tune the parameters of reasoning mechanism (which are equal to the number of rules) instead of the existing heuristic complex parameter identification in the literature. 3) An improved method to select the main system input from all input candidates in the presence of singularity. The proposed systematic method of fuzzy modelling has the advantages of simplicity, flexibility, and high accuracy. The two example data, which have been widely used in the literature as benchmark, are used to evaluate the performance of the proposed method.
VELOCITY-LEVEL KINEMATICS OF THE ATLAS SPHERICAL ORIENTING DEVICE USING OMNI-WHEELS
Authors: Robinson J.D. , Holland J.B. , Hayes M.J.D. , Langlois R.G.
Published: April 2018

Using a novel actuation concept employing omni-directional wheels (or simply omni-wheels), the Atlas simulator motion platform provides unlimited angular displacement about any axis. The Atlas concept completely decouples the orienting and positioning degrees-of-freedom and further decouples each of the positioning degrees-of-freedom. It consists of an omni-wheel driven sphere for orientation that has its geometric centre positioned by an $XYZ$-table. The Jacobian of the orienting device is independent of time and dependent only on the mechanism architecture, meaning that it is always invertible for any configuration provided that the initial design parameters do not result in architecture singularities. An examination of the Atlas Jacobian and its determinant identifies architecture singular design conditions. It is found that these are not design limiting. Discussion highlights the uniqueness of the Atlas concept and its associated kinematic advantages.
THE OPTICS OF THE COMPRESSIBLE N = 2 VORTEX
Authors: Vatistas Georgios H.
Published: April 2018

This paper deals with the refracted shadows generated by the n = 2 compressible vortex. A more pragmatic picture of the optical phenomenon emerges when the flow instead of being isentropic is permitted to transfer heat and dissipate mechanical energy. The visual side of the formulation adheres to the long-established shadowgraph technique. It is shown that although the constant entropy hypothesis retains the qualitative nature of the phenomenon, the present approach improves on the quantitative side of the problem. It reveals that the central dark disk boundary does not mark the vortex core radius, renders the center of the vortex slightly darker, and the halo considerably brighter than the earlier isentropic flow estimates. Furthermore, it offers an alternative explanation for the peculiar set of alternating dark and bright circular bands that appeared in the shadow imprints of an earlier blade tip vortex experiment. The improved methodology can now be used to advance the experimental description of compressible vortices through shadowgraphy.
GENERALIZATION OF AN ANALYTICAL TWO-PHASE STEAM FLOW CALCULATOR TO HIGH-PRESSURE CASES
Authors: Kermani M. J. , Zayemouri M. , Avval M. Saffar
Published: April 2018

Extension of a recently developed analytical two-phase steam flow calculator to high pressure cases is performed in this paper. The initial solution, obtained in earlier study was developed for low pressure cases. In low pressure cases, the vapor portion of the two-phase mixture reliably obeys the ideal gas Equation of State (EOS). In the present high pressure study, real gas effects are included using the more suitable EOS of “Lee-Kesler”. The model similar to the low pressure model assumes local equilibrium between the phases, in which condensation onsets as soon as the saturation line is closed. Before the condensation onset, the stagnation properties echo those at the inflow. However, beyond the condensation onset, the transfer of latent heat toward the vapor portion of the two-phase mixture rises its stagnation temperature. To evaluate this rise in the vapor portion stagnation temperature, a non dimensional parameter ζ is defined. Comparison for low- and high-pressure cases between the present analytical solution and the published experimental values in the literature show very good agreement.
POTENTIAL OF BRAGG GRATING SENSORS FOR AIRCRAFT HEALTH MONITORING
Authors: Mrad Nezih
Published: April 2018

The increased requirement to operate military platforms and aerospace structures beyond their designed life imposes heavy maintenance and inspection burden on aircraft operators and owners. In-service structural health monitoring is potentially a cost-effective approach by which service usage information can be obtained and knowledgeable decisions can be made. Advanced sensor technology, such as optical fibres, are expected to provide existing and future aircraft with added intelligence and functionality, reduced weight and cost, enhanced robustness and performance. This paper furthers the understanding of technical and practical issues related to full implementation of a fibre optic sensor based structural health monitoring system for aerospace and military platforms. It also reports experimental findings on the use of fibre Bragg grating sensors for measurement of parameters relevant to aircraft structural monitoring and smart structures; with an emphasis on the suitability of multifunctional fibre optic sensor system. Experimental evaluations revealed that Bragg grating sensors correlate well with conventional sensors technology for temperature, stain, crack growth and cure monitoring and were insensitive to pressures up to 300 psi. These sensors were determined to have minimum impact on the structural integrity when embedded parallel to host fibres into composite laminates. Recommendations on the implementation and integration of these sensors into a structural health monitoring system are also provided.
EXPERIMENTAL IDENTIFICATION OF CONFIGURATION DEPENDENT LINKAGE VIBRATION IN A PARALLEL ROBOT USING SMART MATERIAL ACTUATORS AND SENSORS
Authors: Wang Xiaoyun , Mills James K.
Published: April 2018

A new lightweight planar parallel robot is designed to achieve high acceleration and execute high-speed pick and place tasks. However, due to the lightweight structure of the system, unwanted structural vibrations are induced during motion of the platform. This work focuses on the investigation of the characteristics of this structural vibration utilizing distributed Lead Zirconate Titanate (PZT) transducers. Experimental Modal Analysis (EMA) tests were performed on an experimental three degree of freedom planar parallel robot with one flexible linkage, for cases in which the robot is stationary and in motion. For both cases, configuration dependency of link structural vibration is investigated by performing EMA in different configurations using different combinations of transducers. It is observed that FRFs obtained for the case in which the robot is in motion have more complex frequency compositions and more - significant configuration-dependency than those in which the robot is stationary. However, the two groups of analyses exhibit two nearly identical most-significant modes. Based on this observation, the transfer function from motor inputs to linkage vibration is simplified permitting an linear active vibration controller to be used.
A PROJECTED GRADIENT AUGMENTED LAGRANGIAN APPROACH TO MULTI-OBJECTIVE TRAJECTORY PLANNING OF REDUNDANT ROBOTS
Authors: KHOUKHI Amar , BARON Luc , BALAZINSKI Marek
Published: April 2018

In this paper, a multi-objective trajectory planning system is developed for redundant manipulators. This system involves kinematic redundancy resolution, as well as robot dynamics, including actuators model. The kinematic redundancy is taken into account through a secondary criterion of joint limits avoidance. The optimization procedure is performed subject to limitations on actuator torques and workspace, while passing through imposed poses. The Augmented Lagrangian with decoupling (ALD) technique is used to solve the resulting constrained non-convex and non-linear optimal control problem. Furthermore, the final state constraint is solved using a gradient projection. Simulations on a three degrees of freedom planar redundant serial manipulator show the effectiveness of the proposed system.
GEOMETRIC OPTIMIZATION OF PLANAR 3-R

P

R PARALLEL MECHANISMS
Authors: Jiang Qimi , Gosselin Clément M.
Published: April 2018

To pursue the maximal singularity-free workspace of parallel mechanisms is a very important concern for robot designers. This paper focuses on the case of planar 3-RPR parallel mechanisms. First, a relatively simple singularity equation of any point on the platform is derived. The obtained singularity equation shows that the singularity locus of any point on the platform is a circle of the same size, as long as the base and the platform are similar triangles. Furthermore, the three centres of the workspace circles lie exactly on the singularity circle. With these useful observations, the singularity-free workspace as well as the maximal leg length ranges can be determined. For a base of unit area, it is found that robots with equilateral triangle base and platform can obtain the maximal singularity-free workspace. Three case studies demonstrate this observation. Finally, a procedure for this kind of robot geometric design is provided.
SELF CALIBRATION OF 3-PRS MANIPULATOR WITHOUT REDUNDANT SENSORS
Authors: O’Brien S. M. , Carretero J. A. , Last P.
Published: April 2018

In this paper a new calibration strategy that does not require any sensors beyond those used to control actuators is applied to the 3-PRS parallel manipulator. Parallel manipulators have several advantages over their serial counterparts, but have seen limited use because of low accuracy, among other reasons. Calibration allows the kinematic model that is used to control the manipulator to be adjusted to more closely replicate the physical manipulator. The architecture and kinematics of the 3-PRS are presented, as well an explanation of this new calibration strategy. The strategy makes use of direct kinematic singularities to obtain the redundant information required for calibration Implementation of the algorithms accomplished via a nested series of optimization problems, each one accomplishing a simpler stage of the overall procedure. A simulated calibration is performed, and the algorithm successfully returns the exact values used to generate the test data.
EXPERIMENTAL CALIBRATION OF THE CONSTRAINING LINKAGE OF A 4 DEGREES OF FREEDOM PARALLEL MANIPULATOR
Authors: Notash Leila , Horne Andrew , Lee Victoria
Published: April 2018

In this article, an experimental calibration of the constraining linkage of a wire-actuated parallel robot is discussed. The experimental test bed includes a prototyped 4 degrees of freedom wire-actuated parallel manipulator and an optical tracking system. The parallel manipulator employs hybrid actuation of joints and wires and includes a rigid branch to constrain the motion of its mobile platform in roll and yaw rotations. The kinematic calibration of the rigid branch is performed. A point-to-point path is designed for the manipulator and an optical tracking system is used as an external measuring device to track a tool attached to the mobile platform and to register the manipulator poses. The deviation between the actual (measured) pose of the mobile platform and the calculated pose (via direct kinematics using the joint encoders), which could be due to errors in the kinematic parameters, actuators and sensors, is used as the error function.
MIXED CONVECTION IN AN INCLINED AND LID-DRIVEN RECTANGULAR ENCLOSURE HEATED AND COOLED ON ADJACENT WALLS
Authors: Öğüt Elif Büyük
Published: April 2018

Steady, laminar, mixed convection flow was considered in an inclined lid-driven rectangular enclosure heated from one side moving with a constant speed and cooled from the stationary adjacent side while the other sides are kept stationary and adiabatic. The governing equations were solved numerically for the stream function, vorticity, and temperature ratio using the differential quadrature method for various Reynolds, Grashof, and Richardson numbers as well as different aspect ratios and inclination angles for the enclosure. The results show that the motion of the side wall, the aspect ratio, and the inclination angle of the enclosure had significant effects on the flow and temperature fields.
SPHERICAL FOUR-BAR MOTION GENERATION WITH A PRESCRIBED RIGID-BODY LOAD
Authors: SHEN QIONG , RUSSELL KEVIN , SODHI RAJ S. , HE YONG
Published: April 2018

In motion generation, the objective is to calculate the mechanism parameters required to achieve or approximate a set of prescribed rigid-body positions. This work introduces a new design constraint that considers driving link static torque for a given rigid-body load. By incorporating this new constraint into a conventional spherical four-bar motion generation model [1], spherical four-bar mechanisms are synthesized to achieve-not only prescribed rigid-body positions-but also satisfy a maximum driver static torque for a given rigid-body load.
COST-EFFECTIVE AND RELIABLE DESIGN OF A SOLAR THERMAL POWER PLANT
Authors: Aliabadi A. A. , Wallace J. S.
Published: April 2018

A design study was conducted to evaluate the cost-effectiveness of solar thermal power generation in a 50 kWe power plant that could be used in a remote location. The system combines a solar collector-thermal storage system utilizing a heat transfer fluid and a simple Rankine cycle power generator utilizing R123 refrigerant. Evacuated tube solar collectors heat mineral oil and supply it to a thermal storage tank. A mineral oil to refrigerant heat exchanger generates superheated refrigerant vapor, which drives a radial turbogenerator. Supplemental natural gas firing maintains a constant thermal storage temperature irregardless of solar conditions enabling the system to produce a constant 50 kWe output. A simulation was carried out to predict the performance of the system in the hottest summer day and the coldest winter day for southern California solar conditions. A rigorous economic analysis was conducted. The system offers advantages over advanced solar thermal power plants by implementing simple fixed evacuated tube collectors, which are less prone to damage in harsh desert environment. Also, backed up by fossil fuel power generation, it is possible to obtain continued operation even during low insolation sky conditions and at night, a feature that stand-alone PV systems do not offer.
CONJUGATION IN THE DISPLACEMENT GROUP AND MOBILITY IN MECHANISMS
Authors: Hervé Jacques M.
Published: April 2018

The paper deals with the Lie group algebraic structure of the set of Euclidean displacements, which represent rigid-body motions. We begin by looking for a representation of a displacement, which is independent of the choice of a frame of reference. Then, it is a simple matter to prove that displacement subgroups may be invariant by conjugation. This mathematical tool is suitable for solving special problems of mobility in mechanisms.
NUMERICAL SIMULATIONS OF INVISCID AIRFLOWS IN RAMJET INLETS
Authors: Akbarzadeh M. , Kermani M. J.
Published: April 2018

The performances of three different ramjet inlets and an entire ramjet are numerically studied in this paper. The fluid is assumed to be inviscid. Inlet 1 is a SCRAMJET inlet and is chosen from the literature. Inlets 2 and 3 are instead designed based on the Oswatitsch principle. Inlets 2 and 3 produce a series of oblique shocks merging at the engine cowl lip followed by a terminating normal shock just downstream of the inlet throat. In ramjet, the combustion is modeled using a non-uniform volumetric heat source distributed in the combustor area. The position of the terminating normal shock in Inlets 2 and 3 is controlled via the inlet’s back pressure. Instead, in ramjet it is bounded by the amount of heat rate added in combustor and the exhaust nozzle throat area. For the numerical simulations, the Roe (1981) and MacCormack (1969) schemes are used. To prevent the spurious numerical oscillations in high resolution computations by Roe scheme the van Albada flux limiter (1982) is used, while in MacCormack scheme artificial viscosity terms are added to damp the oscillations. To double check the accuracy of the computations, the Fluent software package has also been used. Comparisons show very good agreement.
A COMPUTERIZED APPROACH FOR TOLERANCE ANALYSIS OF DISK CAM MECHANISMS WITH A FLAT-FACED FOLLOWER
Authors: Chang Wen-Tung , Wu Long-long
Published: April 2018

A computerized approach for analyzing the tolerances in disk cam mechanisms with a flat-faced follower is presented in this paper. Based on the simulated higher-pair contact analysis, the kinematic deviation of the follower motion caused by the tolerance amount of each design parameter can be determined numerically. The method is validated by means of analyzing the case of an eccentric circular cam mechanism; such a case has an exact solution of the follower motion error. Compared with the exact solutions, the presented computerized approach is demonstrated to be able to provide excellent accuracy and sufficient efficiency no matter how large the level of the tolerance is. Then, both the offset translating oblique flat-faced follower and the oscillating flat-faced follower cases are given to illustrate the presented method. The presented computerized approach and the obtained results can be helpful for tolerance allocation tasks of disk cam mechanisms with a flat-faced follower.
A STUDY ON A NOVEL QUICK RETURN MECHANISM
Authors: Hsieh Wen-Hsiang , Tsai Chia-Heng
Published: April 2018

This work aims to propose a novel design for quick return mechanisms, and the new mechanism is composed by a generalized Oldham coupling and a slider-crank mechanism. First, the kinematic dimensions that affect the time ratio are found by investigating the geometry of the proposed design. By transforming into its kinematically equivalent mechanism, and then the design equations of time ratio are derived. Furthermore, a design example is given for illustration. Moreover, the design is validated by kinematic simulation using ADAMS software. Finally, a prototype and an experimental setup are established, and the experiment is conducted. The results show that proposed new mechanism is feasible and with reasonable accuracy. In addition, it is more compact and easier to be balanced dynamically than a conventional quick return linkage.
NUMERICAL ASSESSMENT OF REVERSE-FLOW MUFFLERS USING A SIMULATED ANNEALING METHOD
Authors: Chiu Min-Chie
Published: April 2018

Because of the necessity of maintenance and operation in industries in which the equipment layout is occasionally tight, the space for a muffler is constrained. An interest in maximizing the acoustical performance of mufflers within a limited space is of paramount importance. As mufflers hybridized with reverse-flow ducts may visibly increase acoustical performance, the main purpose of this paper is to numerically analyze and maximize their acoustical performance within a limited space. In this paper, a four-pole system matrix for evaluating the acoustic performance —sound transmission loss (STL)— is derived by using a decoupled numerical method. Moreover, simulated annealing (SA), a robust scheme used to search for the global optimum by imitating the metal annealing process, has been used during the optimization process. Before dealing with a broadband noise, the STL’s maximization with respect to a one-tone noise (300 Hz) is introduced for a reliability check on the SA method. Moreover, an accuracy check of the mathematical model is performed. Results reveal that the STL of a muffler with reverse-flow perforated ducts can be maximized at the desired frequency for pure tone elimination; moreover, the noise reduction for a broadband noise can reach 97.5 dB. Consequently, the approach used for the optimal design of the mufflers is simple and effective.
COMBINING TAGUCHI METHOD, PRINCIPAL COMPONENT ANALYSIS AND FUZZY LOGIC TO THE TOLERANCE DESIGN OF A DUAL-PURPOSE SIX-BAR MECHANISM
Authors: Chen Fu-Chen , Tzeng Yih-Fong , Hsu Meng-Hui , Chen Wei-Ren
Published: April 2018

A hybrid approach of combining Taguchi method, principal component analysis and fuzzy logic for the tolerance design of a dual-purpose six-bar mechanism is proposed. The approach is to firstly use the Taguchi orthogonal array to carry out experiments for calculating the S/N ratios of the positional errors to the angular error of the dual-purpose six-bar mechanism. The principal component analysis is then applied to determine the principal components of the S/N ratios, which are transformed via fuzzy logic reasoning into a multiple performance index (MPI) for further analysis of the effect of each control factors on the quality of the mechanism. Through the analysis of response table and diagram, key dimensional tolerances can be classified, which allows the decision of either to tighten the key tolerances to improve mechanism quality or to relax the tolerance of non-key dimensions to reduce manufacturing costs to be made.
A NEW FOUR-BAR LINKAGE COMPLETING DELASSUS’ FINDINGS
Authors: Hervé Jacques M.
Published: April 2018

In 1922, E. Delassus found out four-bar linkages including parallel screw joints (or helical pairs), which are movable with one degree of freedom. The Delassus linkages can move only when geometric conditions based on the Euclidean metric are achieved; their mobility is said to be paradoxical. Delassus stated that there is no paradoxical four-bar linkage with three helical H pairs and one prismatic P pair. In fact, Delassus did one error of logical deduction. After the error detection, the paper introduces a new HHHP linkage with a paradoxical mobility. Its three H axes are parallel and intersect a plane that is orthogonal to the H axes in three points forming an isosceles triangle. The P pair is parallel to the triangle side, which has a variable length. The three pitches have to satisfy one scalar relation. Through the consideration of helical trajectories in relative motions, the new mechanism is related to a geometric property of the right helicoid. Helices with a pitch that is half the helicoid pitch can be drawn on the right helicoid.
MODELING AND MULTI-OBJECTIVE OPTIMIZATION OF FORWARD-CURVED BLADE CENTRIFUGAL FANS USING CFD AND NEURAL NETWORKS
Authors: Khalkhali Abolfazl , Farajpoor Mehdi , Safikhani Hamed
Published: April 2018

In the present study, multi-objective optimization of Forward-Curved (FC) blade centrifugal fans is performed in three steps. In the first step, Head rise (HR) and the Head loss (HL) in a set of FC centrifugal fan is numerically investigated using commercial software NUMECA. Two meta-models based on the evolved group method of data handling (GMDH) type neural networks are obtained, in the second step, for modeling of HR and HL with respect to geometrical design variables. Finally, using the obtained polynomial neural networks, multi-objective genetic algorithms are used for Pareto based optimization of FC centrifugal fans considering two conflicting objectives, HR and HL.
EXACT LINEARIZATION AND DISCRETIZATION OF NONLINEAR SYSTEMS SATISFYING A LAGRANGE PDE CONDITION
Authors: Sakamoto Takashi , Hori Noriyuki , Ochi Yoshimasa
Published: April 2018

A sufficient condition for exact linearization of a nonlinear system via an exponential transformation is obtained as a Lagrange partial differential equation. When its solution can be found, the transformation is determined such that the nonlinear systemis exactly converted into a linear system with arbitrary dynamics. When the transformation is invertible, this technique can be applied to exact discretization. Several examples are given to demonstrate the linearization and discretization processes and associated conditions. Asimulation result is presented to show that, under proper conditions, the obtained discrete-time model gives values that are identical to the continuous-time original at discrete-time instants for any sampling intervals.
THE CALIBRATION OF AN ARRAY OF ACCELEROMETERS
Authors: Dubé Dany , Cardou Philippe
Published: April 2018

An accelerometer-array calibration method is proposed in this paper by which we estimate not only the accelerometer offsets and scale factors, but also their sensitive directions and positions on a rigid body. These latter parameters are computed from the classical equations that describe the kinematics of rigid bodies, and by measuring the accelerometer-array displacements using a magnetic sensor. Unlike calibration schemes that were reported before, the one proposed here guarantees that the estimated accelerometer-array parameters are globally optimum in the least-squares sense. The calibration procedure is tested on OCTA, a rigid body equipped with six biaxial accelerometers. It is demonstrated that the new method significantly reduces the errors when computing the angular velocity of a rigid body from the accelerometer measurements.
PITTING DAMAGE LEVELS ESTIMATION FOR PLANETARY GEAR SETS BASED ON MODEL SIMULATION AND GREY RELATIONAL ANALYSIS
Authors: Zhe Cheng , Niaoqing Hu , Fengshou Gu , Guojun Qin
Published: April 2018

The planetary gearbox is a critical mechanism in helicopter transmission systems. Tooth failures in planetary gear sets will cause great risk to helicopter operations. A gear pitting damage level estimation methodology has been devised in this paper by integrating a physical model for simulation signal generation, a three-step statistic algorithm for feature selection and damage level estimation for grey relational analysis. The proposed method was calibrated firstly with fault seeded test data and then validated with the data of other tests from a planetary gear set. The estimation results of test data coincide with the actual test records, showing the effectiveness and accuracy of the method in providing a novel way to model based methods and feature selection and weighting methods for more accurate health monitoring and condition prediction.
TRANSACTIONSOF THE CANADIAN SOCIETY FORMECHANICAL ENGINEERING SPECIAL ISSUE ON MECHANISMS, MACHINES AND MECHATRONICS GUEST EDITORIAL
Authors: Hayes M. John D. , Boudreau Roger
Published: April 2018

The Canadian Committee for the Theory of Machines and Mechanisms (CCToMM) was formally recognized as a national committee member of the International Federation for the Theory of Machines and Mechanisms (IFToMM) at the Third World Congress on Theory of Machines and Mechanisms, held in Dubrovnik in 1971. CCToMM, as a national committee member of IFToMM, shares the objectives of the latter, namely, the promotion of research and development in the field of Machines and Mechanisms by theoretical and experimental methods, along with their practical applications.

Every two years since its inception in 1972, CSME sponsors a national forum, in even numbered years, to promote the communication and transfer of technology between mechanical engineering experts, now known as the CSME Congress. At these congresses, which are hosted by different universities across Canada, CCToMM has negotiated a symposium to be held as a parallel session. CCToMM began organizing its own biennial M3 (Mechanisms, Machines, and Mechatronics) symposia in alternating years (the odd-numbered years). In 1999, the first CCToMM M3 Symposium was held as a stand-alone one-day event, but has grown into an event requiring two days. In an effort to highlight the high quality of a number of the works presented in the symposium, CCToMM has established the practice of publishing selected papers from the symposia in special editions of the Transactions of the Canadian Society for Mechanical Engineering.

Continuing with this practice, this Special Issue presents eight papers selected from the proceedings of the 2011 CCToMM M3 Symposium hosted at McGill University in Montreal, QC, June 2–3, 2011. The symposium was co-chaired by Professors József Kövecses, Roger Boudreau, and Juan A. Carretero. Eighteen full papers and five extended abstracts were accepted for presentation and organized into seven sessions: Control; Dynamics I; Kinematics; Wire Actuated Parallel Manipulators; Dynamics II; Design and Implementation; and Wire Actuated Parallel Manipulators and Failure Analysis.

All of the papers submitted to the 2011 CCToMM M3 Symposium were first subject to examination by at least two independent reviewers prior to the symposium. The eight selected papers subsequently underwent complete Transactions of the Canadian Society for Mechanical Engineering peer-review. Acceptance into this Special Issue was based on completion of the reviewers recommended and mandatory changes and final examination by the Guest Editors.
GEOMETRIC ANALYSIS OF THE KINEMATIC SENSITIVITY OF PLANAR PARALLEL MECHANISMS
Authors: Saadatzi Mohammad Hossein , Masouleh Mehdi Tale , Taghirad Hamid D. , Gosselin Clément , Cardou Philippe
Published: April 2018

The kinematic sensitivity is a unit-consistent measure that has been recently proposed as a mechanism performance index to compare robot architectures. This paper presents a robust geometric approach for computing this index for the case of planar parallel mechanisms. The physical meaning of the kinematic sensitivity is investigated through different combinations of the Euclidean and infinity norms and by means of several illustrative examples. Finally, this paper opens some avenues to the dimensional synthesis of parallel mechanisms by exploring the meaning of the global kinematic sensitivity index.