Deuse, J & Deckert, C 2006, 'Lean Steel Production - Lean production processes in the steel industry', Stahl und Eisen, vol. 126, no. 6, pp. 84-86.
Deuse, J, Petzelt, D & Sackermann, R 2006, 'Modellbildung im Industrial Engineering', Zeitschrift für wirtschaftlichen Fabrikbetrieb, vol. 101, no. 1-2, pp. 66-69.
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Kurzfassung Der Begriff „Digitale Fabrik“ beschreibt den durchgängigen Einsatz von IT-Werkzeugen in allen Phasen der Produktentstehung. Insbesondere für das Aufgabenspektrum des Industrial Engineering erlangt der Einsatz digitaler Modelle, Methoden und Hilfsmittel zunehmend an Bedeutung. Die primäre Zielsetzung besteht in der Reduzierung des Planungsaufwands bei gleichzeitiger Erhöhung der Planungsqualität. Digitale Modelle sind jedoch nicht geeignet, konventionelle, materielle Modelle vollständig zu substituieren. In diesem Beitrag werden die spezifischen Einsatzmöglichkeiten sowohl materieller als auch immaterieller, digitaler Modelle diskutiert und hinsichtlich ihrer Eignung für unterschiedliche Anwendungsfälle im Industrial Engineering bewertet.
Ha, QP & Dissanayake, G 2006, 'Robust Formation Using Reactive Variable Structure Systems', International Transactions on Systems Science and Applications, vol. 1, no. 2, pp. 181-189.
Halkon, BJ & Rothberg, SJ 2006, 'Rotor Vibration Measurements Using Laser Doppler Vibrometry: Essential Post-Processing for Resolution of Radial and Pitch/Yaw Vibrations', Journal of Vibration and Acoustics, vol. 128, no. 1, pp. 8-20.
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Laser Doppler vibrometry is now a well established technique enabling noncontact vibration measurements in the most challenging of environments. Rotor vibration measurements are often highlighted as a major application of laser vibrometers due to their noncontact operation and inherent immunity to shaft runout. In such measurements, resolution of the individual axial and torsional vibration components is possible via particular arrangement of the laser beam(s). Resolution of the radial or pitch/yaw vibration components, however, can only be achieved by essential post-processing of the data from simultaneous orthogonal measurements. This paper describes the principle and rigorous examination of a novel, dedicated resolution algorithm enabling, for the first time, real-time post-processing of the outputs from standard commercial instruments. The system performed well, even in the presence of noise and other typical measurement errors, and was implemented successfully in an engine vibration study.
Halkon, BJ & Rothberg, SJ 2006, 'Vibration measurements using continuous scanning laser vibrometry: Advanced aspects in rotor applications', Mechanical Systems and Signal Processing, vol. 20, no. 6, pp. 1286-1299.
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This paper builds on previous work concerned with the development of a comprehensive velocity sensitivity model for continuous scanning Laser Vibrometry. This versatile model predicts the measured velocity for arbitrary mirror scan angles and arbitrary target motion and it has been especially valuable in revealing the sources of additional components seen in continuous scanning and tracking measurements on rotors. The application to vibration measurements on rotors is the particular focus of this paper which includes, for the first time, a three-dimensional consideration of the incident point on the target and validation of the DC component of measured velocity leading to evaluation of the individual components of the small but inevitable misalignments between the rotor and optical axes. This has not previously been possible. Misalignments in the region 0.5 mm and 0.5° were found and the model shows how additional components of the order 10-20 mm/s result for typical measurements. Such levels are significant as they are comparable with vibration levels likely in real applications and, if unexpected, may lead to data misinterpretation. The first thorough analysis of laser speckle effects in scanning Laser Vibrometer measurements on rotors is presented in the form of a speckle repeat map, together with experimental data quantifying the dramatic reduction in speckle noise found in tracking measurements. Finally, the velocity sensitivity model and the description of laser speckle effects are used to enable confident interpretation of data from a series of measurements on a rotating bladed disc. © 2005 Elsevier Ltd. All rights reserved.
Ji, JC 2006, 'Nonresonant Hopf bifurcations of a controlled van der Pol-Duffing oscillator', JOURNAL OF SOUND AND VIBRATION, vol. 297, no. 1-2, pp. 183-199.
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The trivial equilibrium of a van der Pol-Duffing oscillator with a nonlinear feedback control may lose its stability via Hopf bifurcations, when the time delay involved in the feedback control reaches certain values. Nonresonant Hopf-Hopf interactions may occur in the controlled van der Pol-Duffing oscillator when the corresponding characteristic equation has two pairs of purely imaginary roots. With the aid of normal form theory and centre manifold theorem as well as a perturbation method, the dynamic behaviour of the nonresonant co-dimension two bifurcation is investigated by studying the possible solutions and their stability of the four-dimensional ordinary differential equations on the centre manifold. In the vicinity of the nonresonant Hopf bifurcation, the oscillator may exhibit the initial equilibrium solution, two periodic solutions as well as a quasi-periodic solution on a two-dimensional torus, depending on the dummy unfolding parameters and nonlinear terms. The analytical predictions are found to be in good agreement with the results of numerical integration of the original delay differential equation. © 2006 Elsevier Ltd. All rights reserved.
Jiang, ZY, Tieu, AK, Sun, WH, Tang, JN & Wei, DB 2006, 'Characterisation of thin oxide scale and its surface roughness in hot metal rolling', Materials Science and Engineering: A, vol. 435-436, no. NA, pp. 434-438.
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The deformation of the thin oxide scale formed in hot metal rolling and its surface roughness characterisation are very important for the quality of the finished product. Finite element (FE) simulation of the thin oxide scale deformation and surface roughness transfer has been carried out. The authors focus on the surface asperity deformation of the thin oxide scale and strip. Surface characterisation and the mechanics of the thin oxide scale deformation are obtained from the FE simulation and experimental measurements. Simulation results are close to the measured values. The forming features of surface roughness transfer during hot metal rolling with lubrication are also discussed. (c) 2006 Elsevier B.V. All rights reserved.
Kirchner, N, Paul, G, Liu, DK & PRESS, WUT 2006, 'Bridge maintenance robotic arm: Mechanical technique to reduce the nozzle force of a sandblastine rig', 1st International Symposium on Digital Manufacture, Vols 1-3, vol. 28, no. 164, pp. 12-18.
Kodagoda, KRS, Wijesoma, WS & Balasuriya, AP 2006, 'CuTE: curb tracking and estimation', IEEE Transactions on Control Systems Technology, vol. 14, no. 5, pp. 951-957.
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The number of road accident related fatalities and damages are reduced substantially by improving road infrastructure and enacting and imposing laws. Further reduction is possible through embedding intelligence onto the vehicles for safe decision making. Road boundary information plays a major role in developing such intelligent vehicles. A prominent feature of roads in urban, semi-urban, and similar environments, is curbs on either side defining the road's boundary. In this brief, a novel methodology of tracking curbs is proposed. The problem of tracking a curb from a moving vehicle is formulated as tracking of a maneuvering target in clutter from a mobile platform using onboard sensors. A curb segment is presumed to be the maneuvering target, and is modeled as a nonlinear Markov switching process. The target's (curb's) orientation and location measurements are simultaneously obtained using a two-dimensional (2-D) scanning laser radar (LADAR) and a charge-coupled device (CCD) monocular camera, and are modeled as traditional base state observations. Camera images are also used to estimate the target's mode, which is modeled as a discrete-time point process. An effective curb tracking algorithm, known as Curb Tracking and Estimation (CuTE) using multiple modal sensor information is, thus, synthesized in an image enhanced interactive multiple model filtering framework. The use and fusion of camera vision and LADAR within this frame provide for efficient, effective, and robust tracking of curbs. Extensive experiments conducted in a campus road network demonstrate the viability, effectiveness, and robustness of the proposed method. © 2006 IEEE.
Kwok, NM, Liu, DK & Dissanayake, G 2006, 'Evolutionary computing based mobile robot localization', ENGINEERING APPLICATIONS OF ARTIFICIAL INTELLIGENCE, vol. 19, no. 8, pp. 857-868.
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Evolutionary computing techniques, including genetic algorithms (GA), particle swarm optimization (PSO) and ants system (AS) are applied to the localization problem of a mobile robot. Salient features of robot localization are that the system is partially dynamic and information for fitness evaluation is incomplete and corrupted by noise. In this research, variations to the above three evolutionary computing techniques are proposed to tackle the specific dynamic and noisy system. Their performances are compared based on simulation and experiment results and the feasibility of the proposed approach to mobile robot localization is demonstrated.
Leung, C, Huang, S, Kwok, N & Dissanayake, G 2006, 'Planning under uncertainty using model predictive control for information gathering', Robotics and Autonomous Systems, vol. 54, no. 11, pp. 898-910.
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This paper considers trajectory planning problems for autonomous robots in information gathering tasks. The objective of the planning is to maximize the information gathered within a finite time horizon. It is assumed that either the Extended Kalman Filter (EKF) or the Extended Information Filter (EIF) is applied to estimate the features of interest and the information gathered is expressed by the covariance matrix or information matrix. It is shown that the planning process can be formulated as an optimal control problem for a nonlinear control system with a gradually identified model. This naturally leads to the Model Predictive Control (MPC) planning strategy, which uses the updated knowledge about the model to solve a finite horizon optimal control problem at each time step and only executes the first control action. The proposed MPC framework is demonstrated through solutions to two challenging information gathering tasks: (1) Simultaneous planning, localization, and map building (SPLAM) and (2) Multi-robot Geolocation. It is shown that MPC can effectively deal with dynamic constraints, multiple robots/features and a range of objective functions. © 2006 Elsevier Ltd. All rights reserved.
Leung, C, Huang, S, Kwok, N & Dissanayake, G 2006, 'Planning under uncertainty using model predictive control for information gathering', ROBOTICS AND AUTONOMOUS SYSTEMS, vol. 54, no. 11, pp. 898-910.
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Li, C & Dai, W 2006, 'The Application of Grey Relation Close Degree Model in the Fault Diagnosis', Mechanics Research Communications, vol. 33, no. 5, pp. 614-619.
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In this paper, the dynamics of a system of two van der Pol oscillators with delayed position and velocity coupling is studied by the method of averaging together with truncation of Taylor expansions. According to the slow-flow equations, the dynamics of 1:1 internal resonance is more complex than that of non-1:1 internal resonance. For 1:1 internal resonance, the stability and the number of periodic solutions vary with different time delay for given coupling coefficients. The condition necessary for saddle-node and Hopf bifurcations for symmetric modes, namely in-phase and out-of-phase modes, are determined. The numerical results, obtained from direct integration of the original equation, are found to be in good agreement with analytical predictions. © 2005 Elsevier Ltd. All rights reserved.
Li, X, Ji, JC & Hansen, CH 2006, 'Dynamics of two delay coupled van der Pol oscillators', MECHANICS RESEARCH COMMUNICATIONS, vol. 33, no. 5, pp. 614-627.
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In this paper, the dynamics of a system of two van der Pol oscillators with delayed position and velocity coupling is studied by the method of averaging together with truncation of Taylor expansions. According to the slow-flow equations, the dynamics of 1: 1 internal resonance is more complex than that of non-1: 1 internal resonance. For 1: 1 internal resonance, the stability and the number of periodic solutions vary with different time delay for given coupling coefficients. The condition necessary for saddle-node and Hopf bifurcations for symmetric modes, namely in-phase and out-of-phase modes, are determined. The numerical results, obtained from direct integration of the original equation, are found to be in good agreement with analytical predictions.
Li, X, Ji, JC & Hansen, CH 2006, 'Non-linear normal modes and their bifurcation of a two DOF system with quadratic and cubic non-linearity', INTERNATIONAL JOURNAL OF NON-LINEAR MECHANICS, vol. 41, no. 9, pp. 1028-1038.
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The non-linear normal modes (NNMs) and their bifurcation of a complex two DOF system are investigated systematically in this paper. The coupling and ground springs have both quadratic and cubic non-linearity simultaneously. The cases of ω1:ω2 = 1:1, 1:2 and 1:3 are discussed, respectively, as well as the case of no internal resonance. Approximate solutions for NNMs are computed by applying the method of multiple scales, which ensures that NNM solutions can asymtote to linear normal modes as the non-linearity disappears. According to the procedure, NNMs can be classified into coupled and uncoupled modes. It is found that coupled NNMs exist for systems with any kind of internal resonance, but uncoupled modes may appear or not appear, depending on the type of internal resonance. For systems with 1:1 internal resonance, uncoupled NNMs exist only when coefficients of cubic non-linear terms describing the ground springs are identical. For systems with 1:2 or 1:3 internal resonance, in additional to one uncoupled NNM, there exists one more uncoupled NNM when the coefficients of quadratic or cubic non-linear terms describing the ground springs are identical. The results for the case of internal resonance are consistent with ones for no internal resonance. For the case of 1:2 internal resonance, the bifurcation of the coupled NNM is not only affected by cubic but also by quadratic non-linearity besides detuning parameter although for the cases of 1:1 and 1:3 internal resonance, only cubic non-linearity operate. As a check of the analytical results, direct numerical integrations of the equations of motion are carried out. © 2006 Elsevier Ltd. All rights reserved.
Li, XY, Ji, JC, Hansen, CH & Tan, CX 2006, 'The response of a Duffing-van der Pol oscillator under delayed feedback control', JOURNAL OF SOUND AND VIBRATION, vol. 291, no. 3-5, pp. 644-655.
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The nonlinear dynamics of a Duffing-van der Pol oscillator under linear-plus-nonlinear state feedback control with a time delay are investigated. By means of the averaging method and Taylor expansion, two slow-flow equations for the amplitude and phase of the primary resonance response are derived, from which the relations between the amplitude and phase of the primary resonance response and all other parameters are obtained, respectively. The singularity analysis of the equation governing the amplitude of the primary resonance response shows that the bifurcation modes are perturbations of the pitchfork bifurcation. Conditions preventing multiple solutions, corresponding to two different kinds of bifurcation modes, are given, since cases for which multiple solutions are available should be avoided. The stable condition for steady-state response is also given by the Routh-Hurwitz criterion. It is also shown that coupled nonlinear state feedback control can be replaced by uncoupled nonlinear state feedback control.
Liu, DK, Wu, X, Paul, G, Dissanayake, G & PRESS, WUT 2006, 'Case studies on an approach to multiple autonomous vehicle motion coordination', 1st International Symposium on Digital Manufacture, Vols 1-3, vol. 26, no. 164, pp. 26-31.
Luo, Q & Tong, L 2006, 'A sequential linear least square algorithm for tracking dynamic shapes of smart structures', International Journal for Numerical Methods in Engineering, vol. 67, no. 1, pp. 66-88.
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Luo, Q & Tong, L 2006, 'High precision shape control of plates using orthotropic piezoelectric actuators', Finite Elements in Analysis and Design, vol. 42, no. 11, pp. 1009-1020.
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Luo, Z, Chen, L-P, Yang, J & Zhang, Y-Q 2006, 'Multiple stiffness topology optimizations of continuum structures', The International Journal of Advanced Manufacturing Technology, vol. 30, no. 3-4, pp. 203-214.
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This paper presents a new multi-objective topology optimization algorithm for continuum structures under multiple loading cases. An expert evaluation method of weights based on grey system theory is proposed to calculate the objective weights when the compromise programming approach is employed as a multi-objective optimization scheme converting the multi-objective problem to a single objective problem. A modified updating scheme with a self-adaptive move limit for design variables is also suggested, SIMP is regarded as density-stiffness interpolation scheme and the optimality criteria method is used as the optimizer. Numerical instabilities, such as checkerboards and mesh dependencies, are also discussed. The validities of these methods in this paper are demonstrated by some numerical applications.
Luo, Z, Chen, L-P, Yang, J, Zhang, Y-Q & Abdel-Malek, K 2006, 'Fuzzy tolerance multilevel approach for structural topology optimization', Computers & Structures, vol. 84, no. 3-4, pp. 127-140.
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This paper presents a novel methodology, fuzzy tolerance multilevel programming approach, for applying fuzzy set theory and sequence multilevel method to multi-objective topology optimization problems of continuum structures undergoing multiple loading cases. Ridge-type nonlinear membership functions in fuzzy set theory an. applied to embody fuzzy and uncertain characteristics essentially involved by the objective and constraint functions. Sequence multilevel method is used to characterize the different priorities of loading cases at different levels making contribution to the final optimum solution, which is practically beneficial to reduce the subjective influence transferred by using weighted approaches. The solid isotropic material with penalization (SIMP) is adopted as the density-stiffness interpolation scheme to relax the original optimization problem and indicate the dependence of material properties with element pseudo-densities. Sequential linear programming (SLP) is used as the optimizer to solve the multi-objective optimization problem formulated using fuzzy tolerance multilevel programming scheme. Numerical instabilities, such as checkerboards and mesh dependencies are summarized and a duplicate sensitivity filtering method, in favor of contributing to the mesh-dependent optimum designs, is subsequently proposed to regularize the singularity of the optimization problem. The validation of the methodologies presented in this work has been demonstrated by detailed examples of numerical applications
Luo, Z, Du, Y, Chen, L, Yang, J & Abdel-Malek, K 2006, 'Continuum topology optimization for monolithic compliant mechanisms of micro-actuators', Acta Mechanica Solida Sinica, vol. 19, no. 1, pp. 58-68.
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A multi-objective scheme for structural topology optimization of distributed compliant mechanisms of micro-actuators in MEMS condition is presented in this work, in which mechanical flexibility and structural stiffness are both considered as objective functions. The compliant micro-mechanism developed in this way can not only provide sufficient output work but also have sufficient rigidity to resist reaction forces and maintain its shape when holding the work-piece. A density filtering approach is also proposed to eliminate numerical instabilities such as checkerboards, mesh-dependency and one-node connected hinges occurring in resulting mechanisms. SIMP is used as the interpolation scheme to indicate the dependence of material modulus on element-regularized densities. The sequential convex programming method, such as the method of moving asymptotes (MMA), is used to solve the optimization problem. The validation of the presented methodologies is demonstrated by a typical numerical example.
Luo, Z, Yang, J & Chen, L 2006, 'A new procedure for aerodynamic missile designs using topological optimization approach of continuum structures', Aerospace Science and Technology, vol. 10, no. 5, pp. 364-373.
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This paper presents a multi-objective programming scheme for the conceptual design of aerodynamic missile's structure using topological optimization approaches, in which both the compliance and eigenfrequency are regarded as static and dynamic optimization objectives, respectively. During the conceptual design of the aerodynamic missile with multiple loadings, both the multilevel sequential programming approach and the compromising programming method are coupled together to settle the associated difficulties when the whole structure of the missile body is considered as a pre-defined design domain. The compromise programming method is first applied to describe the statically loaded multi-stiffness topology optimization, and the dynamic formulation is used to establish the subsequent optimization problem mainly concerned with free vibration. The main advantage of the proposed scheme is the flexibility of dealing with optimal topology designs for the whole structures of aerodynamic missiles with complicated loading cases. Solid isotropic material with penalization (SIMP) is used as the interpolation scheme to indicate the dependence of material modulus upon regularized element densities. The sequential convex programming approach is applied to solve the optimization problem. An engineering application is used to demonstrate the characteristics of the presented methodologies based on the commercial software package of Hyperworks.OptiStruct at Altair(R
Luo, Z, Yang, J, Chen, L-P, Zhang, Y-Q & Abdel-Malek, K 2006, 'A new hybrid fuzzy-goal programming scheme for multi-objective topological optimization of static and dynamic structures under multiple loading conditions', Structural and Multidisciplinary Optimization, vol. 31, no. 1, pp. 26-39.
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This work presents a hybrid fuzzy-goal multiobjective programming scheme for topological optimization of continuum structures, in which both static and dynamic loadings are considered. The proposed methodology for topological optimization first employs a fuzzy-goal programming scheme at the top level for multi-objective problems with static and dynamic objectives. For the static objective with multi-stiffness cases in the fuzzy-goal formulation, a hybrid approach, involving a hierarchical sequence approach or a hierarchical sequence approach coupled with a compromise programming method, is especially suggested for the statically loaded multi-stiffness structure at the sub-level. Concerning dynamic optimization problems of free vibration cases, nonstructural mass, oscillation of the objective function, and repeated eigenvalues are also discussed. Solid Isotropic Material with Penalization density-stiffness interpolation scheme is used to indicate the dependence of material modulus upon regularized element densities. The globally convergent version of the method of moving asymptotes and the sequential linear programming method are both employed as optimizers. Several applications have been applied to demonstrate the validation of the presented methodologies
Mitchell, R, Cavanagh, M & Eager, D 2006, 'Not all risk is bad, playgrounds as a learning environment for children', International Journal of Injury Control and Safety Promotion, vol. 13, no. 2, pp. 122-124.
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The article discusses the implications of risk-free playgrounds on the development of children's social, cognitive, physical and emotional skills. Some experts would argue that children do not lose interest in playgrounds that is not challenging, while school-aged children indicate that risk free environment is not enjoyable. It concludes that it is important that playgrounds should provide opportunities to allow children to extend themselves in a challenging yet semi-controlled environment.
Saha, SC, Lei, C & Patterson, JC 2006, 'NATURAL CONVECTION IN A TRIANGULAR ENCLOSURE SUBJECT TO PERIODIC THERMAL FORCING', Natural Convection.
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Wei, D, Han, J, Jiang, ZY, Lu, C & Tieu, AK 2006, 'A study on crack healing in 1045 steel', Journal of Materials Processing Technology, vol. 177, no. 1-3, pp. 233-237.
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Alempijevic, A, Kodagoda, S, Underwood, J, Kumar, S, Dissanayake, G & IEEE 1970, 'Mutual information based sensor registration and calibration', 2006 IEEE/RSJ INTERNATIONAL CONFERENCE ON INTELLIGENT ROBOTS AND SYSTEMS, VOLS 1-12, IEEE/RSJ International Conference on Intelligent Robots and Systems, IEEE, Beijing, China, pp. 25-30.
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Knowledge of calibration, that defines the location of sensors relative to each other, and registration, that relates sensor response due to the same physical phenomena, are essential in order to be able to fuse information from multiple sensors. In this paper, a Mutual Information (MI) based approach for automatic sensor registration and calibration is presented. Unsupervised learning of a nonparametric sensing model by maximizing mutual information between signal streams is used to relate information from different sensors, allowing unknown sensor registration and calibration to be determined. Experiments conducted in an office environment are used to illustrate the effectiveness of the proposed technique. Two laser sensors are used to capture people mobbing in an arbitrarily manner in the environment and MI from a number of attributes of the motion are used for relating the signal streams from the sensors. Thus the sensor registration and calibration is achieved without using artificial patterns or pre-specified motions. © 2006 IEEE.
Athapornmongkon, C, Deuse, J & Wong, C 1970, 'Pull Production Cycle-Time under Varying Product Mixes', Proceedings of the 2006 Winter Simulation Conference, 2006 Winter Simulation Conference, IEEE, pp. 1997-2002.
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To satisfy customer requirements and simultaneously fully utilize the production machines, there is a need to determine appropriate cycle time. Especially in pull systems with varying product mixes, accurate cycle time is even more crucial. Accurate cycle time also reduces the need for buffers. When the product mix varies, especially in a pull production system with parallel flow, determination of accurate cycle time becomes problematic. Hence this paper studies the relations between cycle times and product mixes in a parallel pull production system using discrete event simulation. Experiments with varying product mixes for parallel production systems are simulated. The simulation results show that optimal cycle time is inversely proportional to product mixes, when the product mix is 50:50 e.g. 120 sec. should be set to each parallel machine to obtain overall cycle time of 60 sec. However, when the mixes are more than 50:50, the proportional rule is not valid. © 2006 IEEE.
Cheong, CY, Tan, KC, Liu, DK & Xu, JX 1970, 'A multiobjective evolutionary algorithm for solving vehicle routing problem with stochastic demand', 2006 IEEE CONGRESS ON EVOLUTIONARY COMPUTATION, VOLS 1-6, IEEE Congress on Evolutionary Computation, IEEE, Vancouver, CANADA, pp. 1355-+.
Cheong, CY, Tan, KC, Liu, DK & Xu, JX 1970, 'A multiobjective evolutionary algorithm for solving vehicle routing problem with stochastic demand', 2006 IEEE Congress on Evolutionary Computation, CEC 2006, pp. 1370-1377.
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This paper considers the routing of vehicles with limited capacity from a central depot to a set of geographically dispersed customers where actual demand is revealed only when the vehicle arrives at the customer. The solution to this vehicle routing problem with stochastic demand (VRPSD) involves the optimization of complete routing schedules with minimum travel distance, driver remuneration, and number of vehicles, subject to a number of constraints such as vehicle time window and capacity. To solve such a multiobjective combinatorial optimization problem, this paper presents a multiobjective evolutionary algorithm that incorporates two VRPSD-specific heuristics for local exploitation and a route simulation method to evaluate the fitness of solutions. A novel way of assessing the quality of solutions to the VRPSD on top of comparing their expected costs is also proposed. It is shown that the algorithm is capable of finding useful tradeoff solutions which are robust to the stochastic nature of the problem. © 2006 IEEE.
Cheong, CY, Tan, KC, Liu, DK & Xu, JX 1970, 'A Multiobjective Evolutionary Algorithm for Solving Vehicle Routing Problem with Stochastic Demand', 2006 IEEE International Conference on Evolutionary Computation, 2006 IEEE International Conference on Evolutionary Computation, IEEE, Vancouver, Canada, pp. 5519-5526.
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This paper considers the routing of vehicles with limited capacity from a central depot to a set of geographically dispersed customers where actual demand is revealed only when the vehicle arrives at the customer. The solution to this vehicle routing problem with stochastic demand (VRPSD) involves the optimization of complete routing schedules with minimum travel distance, driver remuneration, and number of vehicles, subject to a number of constraints such as vehicle time window and capacity. To solve such a multiobjective combinatorial optimization problem, this paper presents a multiobjective evolutionary algorithm that incorporates two VRPSD-specific heuristics for local exploitation and a route simulation method to evaluate the fitness of solutions. A novel way of assessing the quality of solutions to the VRPSD on top of comparing their expected costs is also proposed. It is shown that the algorithm is capable of finding useful tradeoff solutions which are robust to the stochastic nature of the problem.
Dissanayake, G, Paxman, J, Miro, JV, Thane, O & Thi, H-T 1970, 'Robotics for Urban Search and Rescue', First International Conference on Industrial and Information Systems, First International Conference on Industrial and Information Systems, IEEE, Peradeniya, Sri Lanka, pp. 294-298.
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This paper describes a team of robots that are designed for urban search and rescue applications. The team CASualty consists of four tele-operated robots and one autonomous robot. A brief description of the capabilities of the robot team is presented together with the details of capabilities of the autonomous robot HOMER. In particular, the software architecture, user interface, strategies used for mapping, exploration and the identification of human victims present in the environment are described. The team participated in an international competition on urban search and rescue (RoboCup Rescue) held in Bremen, Germany in June 2006 where HOMER was placed second in the autonomy challenge
Dissanayake, G, Paxman, J, Miro, JV, Thane, O & Thi, H-T 1970, 'Robotics for Urban Search and Rescue', 2006 International Conference on Industrial and Information Systems, 2006 International Conference on Industrial and Information Systems, IEEE, Peradeniya, SRI LANKA, pp. 294-298.
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This paper describes a team of robots that are designed for urban search and rescue applications. The team CASualty consists of four tele-operated robots and one autonomous robot. A brief description of the capabilities of the robot team is presented together with the details of capabilities of the autonomous robot HOMER. In particular, the software architecture, user interface, strategies used for mapping, exploration and the identification of human victims present in the environment are described. The team participated in an international competition on urban search and rescue (RoboCup Rescue) held in Bremen, Germany in June 2006 where HOMER was placed second in the autonomy challenge. ©2006 IEEE.
Ellekilde, L, Valls Miro, J & Dissanayake, G 1970, 'Fusing range and intensity images for generating dense models of three-dimensional environments', Proceedings of the 2006 IEEE International Conference on Man-Machine Systems (ICoMMS 2006), IEEE International Conference on Man-Machine Systems, IET, Langkawi, Malaysia, pp. 1-5.
Ha, QP, Ha, HM & Dissanayake, G 1970, 'Robotic formation control using variable structure systems approach', DIS 2006: IEEE WORKSHOP ON DISTRIBUTED INTELLIGENT SYSTEMS: COLLECTIVE INTELLIGENCE AND ITS APPLICATIONS, PROCEEDINGS, IEEE Workshop on Distributed Intelligent Systems, IEEE Computer Soc, Prague, CZECH REPUBLIC, pp. 37-42.
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This paper addresses robust control of multiple mobile robots moving in desired formations. A rigorous control technique for such an agent-based robotic system may encounter problems of singularity, parameter sensitivity and inter-robot collision. Our pr
Herath, DC, Kodagoda, KRS & Dissanayake, G 1970, 'Modeling Errors in Small Baseline Stereo for SLAM', 2006 9th International Conference on Control, Automation, Robotics and Vision, 2006 9th International Conference on Control, Automation, Robotics and Vision, IEEE, Singapore, pp. 836-841.
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In the past few years, there has been significant advancement in localization and mapping using stereo cameras. Despite the recent successes, reliably generating an accurate geometric map of a large indoor area using stereo vision still poses significant challenges due to the accuracy and reliability of depth information especially with small baselines. Most stereo vision based applications presented to date have used medium to large baseline stereo cameras with Gaussian error models. Here we make an attempt to analyze the significance of errors in small baseline (usually <0.1m) stereo cameras and the validity of the Gaussian assumption used in the implementation of Kalman Filter based SLAM algorithms. Sensor errors are analyzed through experimentations carried out in the form of a robotic mapping. Then we show that SLAM solutions based on the Extended Kalman Filter (EKF) could become inconsistent due to the nature of the observation models used. © 2006 IEEE.
Herath, DC, Kodagoda, KRS & Dissanayake, G 1970, 'Modeling errors in small baseline stereo for SLAM', 2006 9TH INTERNATIONAL CONFERENCE ON CONTROL, AUTOMATION, ROBOTICS AND VISION, VOLS 1- 5, 9th International Conference on Control, Automation, Robotics and Vision, IEEE, Singapore, SINGAPORE, pp. 2034-+.
Herath, DC, Kodagoda, S, Dissanayake, G & IEEE 1970, 'Simultaneous localisation and mapping: A stereo vision based approach', 2006 IEEE/RSJ International Conference on Intelligent Robots and Systems, Vols 1-12, IEEE/RSJ International Conference on Intelligent Robots and Systems, IEEE, Beijing, China, pp. 922-927.
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With limited dynamic range and poor noise performance, cameras still pose considerable challenges in the application of range sensors in the context of robotic navigation, especially in the implementation of Simultaneous Localisation and Mapping (SLAM) with sparse features. This paper presents a combination of methods in solving the SLAM problem in a constricted indoor environment using small baseline stereo vision. Main contributions include a feature selection and tracking algorithm, a stereo noise filter, a robust feature validation algorithm and a multiple hypotheses adaptive window positioning method in 'closing the loop'. These methods take a novel approach in that information from the image processing and robotic navigation domains are used in tandem to augment each other. Experimental results including a real-time implementation in an office-like environment are also presented. © 2006 IEEE.
Huang, S, Dissanayake, G & IEEE 1970, 'Convergence analysis for extended Kalman filter based SLAM', 2006 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION (ICRA), VOLS 1-10, IEEE International Conference on Robots and Automation, IEEE, Orlando, USA, pp. 412-417.
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The main contribution of this paper is a theoretical analysis of the Extended Kalman Filter (EKF) based solution to the simultaneous localisation and mapping (SLAM) problem. The convergence properties for the general nonlinear two-dimensional SLAM are provided. The proofs clearly show that the robot orientation error has a significant effect on the limit and/or the lower bound of the uncertainty of the landmark location estimates. Furthermore, some insights to the performance of EKF SLAM and a theoretical analysis on the inconsistencies in EKF SLAM that have been recently observed are given. © 2006 IEEE.
Huang, S, Wang, Z, Dissanayake, G & IEEE 1970, 'Mapping large scale environments using relative position information among landmarks', 2006 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION (ICRA), VOLS 1-10, IEEE International Conference on Robots and Automation, IEEE, Orlando, FL, pp. 2297-2302.
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The main contribution of this paper is a new SLAM algorithm for the mapping of large scale environments by combining local maps. The local maps can be generated by traditional Extended Kalman Filter (EKF) based SLAM. Relationships between the locations of the landmarks in the local map are then extracted and used in an Extended Information Filter (EIF) to build a global map. An important feature is that the information matrix for the global map is exactly sparse, leading to significant computational advantages. This paper thus presents an algorithm that combines the advantages of both the existing local map joining SLAM algorithms, which reduces the linearization error in EKF SLAM and allows computationally demanding global map fusion to be scheduled off-line, and the Decoupled SLAM (D-SLAM) algorithm, which provides an efficient strategy for building large maps using relative location information. The effectiveness of the new algorithm is illustrated through computer simulations. © 2006 IEEE.
Huynh, P 1970, 'Free Convection Cooling of a Horizontol Cylinder Positioned Above a Plane', Proceedings - 13th International Heat Transfer Conference, International Heat Transfer Conference, Begell House Inc, Sydney, Australia, pp. 1-12.
Jiang, ZY, Zhu, HT, Wei, DB & Tieu, AK 1970, 'An approach to analyse the special rolling of thin strip', Journal of Materials Processing Technology, 11th International Conference on Metal Forming 2006, Elsevier BV, Birmingham, ENGLAND, pp. 130-133.
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Work roll edge contact may affect the mechanics of cold rolling of thin strip and the crown of the rolled strip. In this paper, the authors developed a modified influence function method to simulate this special rolling. The rolling force, intermediate force, roll edge contact force, the crown of the rolled strip and the edge contact length for different strip widths and traverse friction coefficients are obtained. The calculated rolling forces are compared to experimental values. The developed model is effective and applicable in the cold rolling of thin strip with work roll edge contact. (c) 2006 Elsevier B.V. All rights reserved.
Jiang, ZY, Zhu, HT, Wei, DB & Tieu, AK 1970, 'An influence function method to analyse thin strip rolling with work roll edge contact', Proceedings of the 5th International Conference on Engineering Computational Technology.
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In this paper, based on the theory of the slit beam, the cold rolling of thin strip with work roll edge contact was calculated using an influence function method. A comparison of the forces and the strip shape with or without the work roll edge contact was carried out. The effect of the different rolling parameters, such as the reduction, strip width, friction coefficient and transverse friction distribution, on the mechanics and deformation of the cold rolling of thin strip were analysed. The developed model is useful to improve the shape and profile quality of thin strip in cold rolling process. According to the developed method, a comprehensive model which is suitable for simulating work roll edge contact or not can be obtained. © 2006 Civil-Comp Press.
Kirchner, N, Liu, D & Dissanayake, G 1970, 'Bridge Maintenance Robotic Arm: Capacitive Sensor for Obstacle Ranging in Particle Laden Air', Proceedings of the International Symposium on Automation and Robotics in Construction (IAARC), 23rd International Symposium on Automation and Robotics in Construction, International Association for Automation and Robotics in Construction (IAARC), Tokyo, Japan, pp. 596-601.
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This paper describes an Adaptive Capacitive Sensor Network for Obstacle Ranging (ACSOR) that is intended to provide entire arm encompassing obstacle range data for a robotic arm conducting the task of sandblasting a bridge. A multi-channel capacitive sensor capable of dynamic obstacle ranging in air heavily laden with lead contaminated sandblasting refuse has been developed. Experimental results have shown the ACSOR's working range to be 50cm, that it is relatively immune from airborne lead contaminated sandblasting refuse and that it is capable of ranging an obstacle 21cm away whilst fitted to a robotic arm moving at 2cm/s with an obstacle range error of less than 1cm.
Kodagoda, KRS, Alempijevic, A, Underwood, J, Kumar, S & Dissanayake, G 1970, 'Sensor Registration and Calibration using Moving Targets', 2006 9th International Conference on Control, Automation, Robotics and Vision, 2006 9th International Conference on Control, Automation, Robotics and Vision, IEEE, Singapore, pp. 830-835.
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Multimodal sensor registration and calibration are crucially important aspects in distributed sensor fusion. Unknown relationships of sensors and joint probability distribution between sensory signals make the sensor fusion nontrivial. In this paper, we adopt a Mutual Information (MI) based approach for sensor registration and calibration. It is based on unsupervised learning of a nonparametric sensing model by maximizing mutual information between signal streams. Experiments were carried out in an office like environment with two laser sensors capturing arbitrarily moving people. Attributes of the moving targets are used. Problems due to target occlusions are alleviated by the multiple model tracker. The registration and calibration methodology does not require any artificially generated patterns or motions unlike other calibration methodologies. © 2006 IEEE.
Kodagoda, KRS, Alempijevic, A, Underwood, J, Kumar, S & Dissanayake, G 1970, 'Sensor registration and calibration using moving targets', 2006 9TH INTERNATIONAL CONFERENCE ON CONTROL, AUTOMATION, ROBOTICS AND VISION, VOLS 1- 5, 9th International Conference on Control, Automation, Robotics and Vision, IEEE, Singapore, SINGAPORE, pp. 1992-+.
Kodagoda, S, Hemachandra, EASM, Jayasekara, PG, Peiris, RL, De Silva, AC & Munasinghe, R 1970, 'Obstacle Detection and Map Building with a Rotating Ultrasonic Range Sensor using Bayesian Combination', 2006 International Conference on Information and Automation, 2006 International Conference on Information and Automation, IEEE.
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Kodagoda, S, Hemachandra, EASM, Pannipitiya, PAAR, Bartholomeuz, LS & Pasqual, AA 1970, 'Minimal Invasive Headband for Brain Computer Interfacing and Analysis', 2006 International Conference on Information and Automation, 2006 International Conference on Information and Automation, IEEE.
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Kulatunga, AK, Liu, DK, Dissanayake, G & Siyambalapitiya, SB 1970, 'Ant colony optimization based simultaneous task allocation and path planning of autonomous vehicles', 2006 IEEE Conference on Cybernetics and Intelligent Systems, CIS 2006, IEEE International Conference on Cybernetics and Intelligent Systems, IEEE, Bangkok, Thailand, pp. 823-828.
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This paper applies a meta-heuristic based Ant Colony Optimization (ACO) technique for simultaneous task allocation and path planning of Automated Guided Vehicles (AGV) in material handling. ACO algorithm allocates tasks to AGVs based on collision free path obtained by a proposed path and motion planning algorithm. The validity of this approach is investigated by applying it to different task and AGV combinations which have different initial settings. For small combinations, i.e. small number of tasks and vehicles, the quality of the ACO solution is compared against the optimal results obtained from exhaustive search mechanism. This approach has shown near optimal results. For larger combinations, ACO solutions are compared with Simulated Annealing algorithm which is another commonly used meta-heuristic approach. The results show that ACO solutions have slightly better performance than that of Simulated Annealing algorithm. © 2006 IEEE.
Kulatunga, AK, Liu, DK, Dissanayake, G, Siyambalapitiya, SB & IEEE 1970, 'Ant colony optimization based simultaneous task allocation and path planning of autonomous vehicles', 2006 IEEE Conference on Cybernetics and Intelligent Systems, Vols 1 and 2, IEEE Conference on Cybernetics and Intelligent Systems, IEEE, Bangkok, THAILAND, pp. 727-732.
Kwok, NM, Ha, QP, Liu, DK, Fang, G & IEEE 1970, 'Intensity-preserving contrast enhancement for gray-level images using multi-objective particle swarm optimization', 2006 IEEE International Conference on Automation Science and Engineering, Vols 1 and 2, IEEE Conference on Automation Science and Engineering, IEEE, Shanghai, China, pp. 21-26.
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This paper addresses the enhancement of the contrast of gray-level digital images while preserving the mean image intensity, thus, providing better viewing consistence and effectiveness. The contrast enhancement is achieved by maximizing the information content carried in the image with a continuous intensity transform function and the mean image intensity is preserved, by using the gamma-correction approach. Since the contrast enhancement and intensity preservation are contradicting, a multi-objective particle swarm optimization (MPSO) algorithm is developed to resolve this trade-off. Benchmark images, street senses and skyline images are included to illustrate the effectiveness of the proposed approach. © 2006 IEEE.
Kwok, NM, Liu, DK, Tan, KC & Ha, QP 1970, 'An empirical study on the settings of control coefficients in particle swarm optimization', 2006 IEEE Congress on Evolutionary Computation, CEC 2006, pp. 823-830.
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The effects of randomness of control coefficients in Particle Swarm Optimization (PSO) are investigated through empirical studies. The PSO is viewed as a method to solve a coverage problem in the solution space when the global-best particle is reported as the solution. Randomness of the control coefficients, therefore, plays a crucial role in providing an efficient and effective algorithm. Comparisons of performances are made between the uniform and Gaussian distributed random coefficients in adjusting particle velocities. Alternative strategies are also tested, they include: i) pre-assigned randomness through the iterations, ii) selective hybrid random adjustment based on the fitness of the particles. Furthermore, the effect of velocity momentum factor is compared between a constant and random momentum. Numerical results show that performances of the proposed variations are comparable to the conventional implementation for simple test functions. However, enhanced performances using the selective and hybrid strategy are observed for complicate functions. ©2006 IEEE.
Kwok, NM, Liu, DK, Tan, KC, Ha, QP & IEEE 1970, 'An empirical study on the settings of control coefficients in Particle Swarm Optimization', 2006 IEEE CONGRESS ON EVOLUTIONARY COMPUTATION, VOLS 1-6, IEEE Congress on Evolutionary Computation, IEEE, Vancouver BC, Canada, pp. 823-830.
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The effects of randomness of control coefficients in particle swarm optimization (PSO) are investigated through empirical studies. The PSO is viewed as a method to solve a coverage problem in the solution space when the global-best particle is reported as the solution. Randomness of the control coefficients, therefore, plays a crucial role in providing an efficient and effective algorithm. Comparisons of performances are made between the uniform and Gaussian distributed random coefficients in adjusting particle velocities. Alternative strategies are also tested, they include: i) pre-assigned randomness through the iterations, ii) selective hybrid random adjustment based on the fitness of the particles. Furthermore, the effect of velocity momentum factor is compared between a constant and random momentum. Numerical results show that performances of the proposed variations are comparable to the conventional implementation for simple test functions. However, enhanced performances using the selective and hybrid strategy are observed for complicate functions.
Lau, H, Huang, S, Dissanayake, G & IEEE 1970, 'Probabilistic search for a moving target in an indoor environment', 2006 IEEE/RSJ INTERNATIONAL CONFERENCE ON INTELLIGENT ROBOTS AND SYSTEMS, VOLS 1-12, IEEE/RSJ International Conference on Intelligent Robots and Systems, IEEE, Beijing, China, pp. 3393-3398.
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We consider a search for a target moving within a known indoor environment partitioned into interconnected regions of varying sizes. The knowledge of target location is described as a probability distribution over the regions, and the searcher can only move from one region to another as the structure allows. The objective is to find a feasible path through the regions that maximizes the probability of locating the target within fixed time. This problem generalizes the existing optimal searcher path problem (OSP) by additionally stipulating a minimum amount of time that a finite-speed searcher must spend to travel through a region before reaching the next. We propose a technique to obtain the upper bound of detection for solving the problem in a branch and bound framework. Comparisons show that the technique is also superior to known bounding methods for the original optimal searcher path problem. © 2006 IEEE.
Leung, C, Huang, S, Dissanayake, G & IEEE 1970, 'Active SLAM using model predictive control and attractor based exploration', 2006 IEEE/RSJ International Conference on Intelligent Robots and Systems, Vols 1-12, IEEE/RSJ International Conference on Intelligent Robots and Systems, IEEE, Beijing, China, pp. 5026-5031.
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Active SLAM poses the challenge for an autonomous robot to plan efficient paths simultaneous to the SLAM process. The uncertainties of the robot, map and sensor measurements, and the dynamic and motion constraints need to be considered in the planning process. In this paper, the active SLAM problem is formulated as an optimal trajectory planning problem. A novel technique is introduced that utilises an attractor combined with local planning strategies such as Model Predictive Control (a.k.a. Receding Horizon) to solve this problem. An attractor provides high level task intentions and incorporates global information about the environment for the local planner, thereby eliminating the need for costly global planning with longer horizons. It is demonstrated that trajectory planning with an attractor results in improved performance over systems that have local planning alone. © 2006 IEEE.
Liu, DK, Wang, D & Dissanayake, G 1970, 'A Force Field Method Based Multi-Robot Collaboration', 2006 IEEE Conference on Robotics, Automation and Mechatronics, 2006 IEEE Conference on Robotics, Automation and Mechatronics, IEEE, Bangkok, Thailand, pp. 662-667.
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A force field (F2) based multi-robot collaboration method is presented in this paper. In this method, a virtual force field is generated for every moving robot and continuously changing based on the robot status including its traveling speed, dimension, priority, location and environment, etc. The interactions among robots' force fields and obstacles provide a natural way for collision avoidance and collaboration while robots are on their way to goals. In this paper, the definition of reaction force direction is modified to reduce robot orientation oscillations which occur when a robot approaches obstacles or other robots. Then the influence of task priority on motion planning and the problem of deadlock in multi-robot cases are discussed. Simulations in a real indoor environment were carried out and demonstrated the feasibility and effectiveness of this method. © 2006 IEEE.
Liu, DK, Wang, D & Dissanayake, G 1970, 'A force field method based multi-robot collaboration', 2006 IEEE CONFERENCE ON ROBOTICS, AUTOMATION AND MECHATRONICS, VOLS 1 AND 2, IEEE Conference on Robotics, Automation and Mechatronics, IEEE, Bangkok, THAILAND, pp. 511-+.
Liu, DK, Wu, X, Kulatunga, AK & Dissanayake, G 1970, 'Motion coordination of multiple autonomous vehicles in dynamic and strictly constrained environments', 2006 IEEE Conference on Cybernetics and Intelligent Systems, IEEE International Conference on Cybernetics and Intelligent Systems, IEEE, Bangkok, Thailand, pp. 204-209.
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With the increasing applications of fully autonomous vehicles, efficient motion coordination of multi-autonomous vehicles becomes a very important problem as it significantly affects the productivity. This problem is even harder to solve with the increases of the number of autonomous vehicles employed in a dynamic changing environment and constraints to vehicle movement. This paper presents a simultaneous path and motion planning (SiPaMoP) approach to coordinate motions of multi-autonomous vehicles in dynamic and strictly constrained environments. This approach integrates the path planning, collision avoidance and motion planning into a comprehensive model, which has so far not attracted a lot of attention in the academic literature, and optimizes vehicles' path and speed to minimize the completion time of a set of tasks. Simulation results demonstrated that this approach can effectively coordinate the motion of a team of vehicles, and solve the problems of traffic congestion and collision under various traffic conditions. © 2006 IEEE.
Liu, DK, Wu, X, Kulatunga, AK, Dissanayake, G & IEEE 1970, 'Motion coordination of multiple autonomous vehicles in dynamic and strictly constrained environments', 2006 IEEE Conference on Cybernetics and Intelligent Systems, Vols 1 and 2, IEEE Conference on Cybernetics and Intelligent Systems, IEEE, Bangkok, THAILAND, pp. 683-688.
McIntyre, DG, Liu, D, Lasky, V & Murray, SJ 1970, 'A Remote Water-Level Rig Laboratory for e-Learning', Proceedings of the 7th International Conference on Information Technology base Higher Education and Training, International Confernce on Information Technology Base Higher Education and Training, IEEE, Sydney, Australia, pp. 1-5.
McIntyre, DG, Liu, DK, Lasky, VL, Murray, SJ & IEEE 1970, 'A remote water-level rig laboratory for e-learning', 2006 7th International Conference on Information Technology Based Higher Education and Training, Vols 1 and 2, 7th International Conference on Information Technology Based Higher Education and Training, IEEE, Sydney, AUSTRALIA, pp. 77-81.
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Miro, JV, Zhou, W, Dissanayake, G & IEEE 1970, 'Towards vision based navigation in large indoor environments', 2006 IEEE/RSJ International Conference on Intelligent Robots and Systems, Vols 1-12, IEEE/RSJ International Conference on Intelligent Robots and Systems, IEEE, Beijing, China, pp. 2096-2102.
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The main contribution of this paper is a novel stereo-based algorithm which serves as a tool to examine the viability of stereo vision solutions to the simultaneous localisation and mapping (SLAM) for large indoor environments. Using features extracted from the scale invariant feature transform (SIFT) and depth maps from a small vision system (SVS) stereo head, an extended Kalman fllter (EKF) based SLAM algorithm, that allows the independent use of information relating to depth and bearing, is developed. By means of a map pruning strategy for managing the computational cost, it is demonstrated that statistically consistent location estimates can be generated for a small (6 m × 6 m) structured office environment, and in a robotics search and rescue arena of similar size. It is shown that in a larger office environment, the proposed algorithm generates location estimates which are topologically correct, but statistically inconsistent. A discussion on the possible reasons for the inconsistency is presented. The paper highlights that, despite recent advances, building accurate geometric maps of large environments with vision only sensing is still a challenging task. ©2006 IEEE.
Parnell, J & Samuels, S 1970, 'A comparison of tyre/road noise generated on NSW pavements to international studies', 1st Australasian Acoustical Societies' Conference 2006, ACOUSTICS 2006: Noise of Progress, pp. 369-375.
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A study of the tyre/road noise generated by 20 pavements surfaces representing a wide range of construction materials, techniques and surface textures constructed in NSW was undertaken and compared against the results of similar studies of 75 pavements constructed overseas. A range of more than 14 dB in passby noise levels was reported over the pavement types investigated with the NSW data being consistent with international data for similar pavement types. In general a range of low noise asphalts were found to return the lowest overall noise levels followed by concrete pavements that had minimal surface texture. Dense grade and stone mastic asphalts, and exposed aggregate concrete were found to perform better than randomly transverse tyned concrete pavements. Longitudinally tyned concrete pavements are not a design that is used in NSW however in international studies they were found to return noise levels similar to that of dense graded asphalts. Uniformly tyned pavements and those which generate acoustic energy in discrete frequency bands were found to be amongst the loudest pavements. Copyright © (2006) by the Australian Acoustical Society.
Parnell, J & Samuels, S 1970, 'Pavement surfaces and in-cabin noise levels', 1st Australasian Acoustical Societies' Conference 2006, ACOUSTICS 2006: Noise of Progress, pp. 363-367.
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This paper deals with a Roads and Traffic Authority of NSW funded study of the resultant in-cabin noise levels generated by a passenger vehicle travelling under controlled conditions. The objective of the study was to investigate the relationship between externally and internally measured noise levels and to compare the internally measured noise levels with those recorded in overseas studies. The study investigated 20 pavement surfaces that represented a wide range of construction materials and techniques and surface textures adopted in NSW. A range of purportedly low noise asphalt and a dense graded asphalt were found to return the lowest overall noise levels followed by a concrete pavement that had minimal surface texture. A stone mastic asphalt along with an exposed aggregate concrete were found to perform better than randomly transverse tyned concrete pavements. Uniformly tyned concrete pavements and chip seal pavements were found to be amongst the loudest pavements. The present study found that generally, trends in internal noise levels followed those measured externally; however there were some exceptions such as chip seal pavements that recorded higher internal noise levels than did concrete pavements with comparable external noise levels. Copyright © (2006) by the Australian Acoustical Society.
Paul, G & Liu, DK 1970, 'Replanning of multiple autonomous vehicles in material handling', 2006 IEEE CONFERENCE ON ROBOTICS, AUTOMATION AND MECHATRONICS, VOLS 1 AND 2, IEEE Conference on Robotics, Automation and Mechatronics, IEEE, Bangkok, THAILAND, pp. 721-+.
Paul, G & Liu, DK 1970, 'Replanning of Multiple Autonomous Vehicles in Material Handling', 2006 IEEE Conference on Robotics, Automation and Mechatronics, 2006 IEEE Conference on Robotics, Automation and Mechatronics, IEEE, Bangkok, Thailand, pp. 1-6.
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The fully automated docks in Australia present opportunities for applications of autonomous vehicles and engineering innovation. When planning tasks to be done by multi-autonomous vehicles in an enclosed area with a known dynamic map (i.e. bi-directional path network), there are many issues that have not yet been comprehensively solved. The real world presents more complexity than the initial algorithms addressed. There are problems that occur due to interaction with the real-world. This means autonomous vehicles can stop, are affected, or face problems, and hence tasks and vehicles' paths and motion need to be replanned. In order to replan, a greater understanding of the state of vehicles, the state of the map, and importantly the importance of tasks and vehicles is definitely needed. This paper explores the improvements made to replanning by gaining a thorough understanding of the map and then utilising map information to make the best, most efficient replanning decision. Five replanning Methods are investigated and four Options which combine the Methods in different ways, are tested in this research. A map analysis Method is also presented. Simulation studies show that map information based replanning is the most efficient Method out of those tested. © 2006 IEEE.
Taha, T, Miro, J & Liu, D 1970, 'An Efficient Path Planner for Large Mobile Platforms in Cluttered Environments', 2006 IEEE Conference on Robotics, Automation and Mechatronics, 2006 IEEE Conference on Robotics, Automation and Mechatronics, IEEE, Bangkok, Thailand, pp. 225-230.
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This paper presents a one step smooth and efficient path planning algorithm for navigating a large robotic platform in known cluttered environments. The proposed strategy, based on the generation of a novel search space, relies on non-uniform density sampling of the free areas to direct the computational resources to troubled and difficult regions, such as narrow passages, leaving the larger open spaces sparsely populated. A smoothing penalty is also associated to the nodes to encourage the generation of gentle paths along the middle of the empty spaces. Collision detection is carried out off-line during the creation of the configuration space to speed up the actual search for the path, which is done on-line. Results prove that the proposed approach considerably reduces the search space in a meaningful and practical manner, improving the computational cost of generating a path optimised for fine and smooth motion. © 2006 IEEE.
Taha, T, Miro, JV & Liu, D 1970, 'An efficient path planner for large mobile platforms in cluttered environments', 2006 IEEE CONFERENCE ON ROBOTICS, AUTOMATION AND MECHATRONICS, VOLS 1 AND 2, IEEE Conference on Robotics, Automation and Mechatronics, IEEE, Bangkok, THAILAND, pp. 671-+.
Taha, T, Valls Miro, J & Dissanayake, G 1970, 'Sampling based time efficient path planning algorithm for mobile platforms', Proceeding of the 2006 IEEE International Conference on Man-Machine Systems (ICoMMS 2006), IEEE International Conference on Man-Machine Systems, IET, Langkawi, Malaysia, pp. 1-6.
Takezawa, S, Ishimoto, T & Dissanayake, G 1970, 'Optimal Control for Simultaneous Localisation and Mapping Problems in Indoor Environments with Stereo Vision', IECON 2006 - 32nd Annual Conference on IEEE Industrial Electronics, IECON 2006 - 32nd Annual Conference on IEEE Industrial Electronics, IEEE, pp. 4749-4754.
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This paper proposes a optimal control method for simultaneous localisation and mapping (SLAM) in an indoor environment using stereo vision. Specially designed artificial landmarks distributed in the environment are observed and extracted from a camera image. The disparity map obtained from the stereo vision system is used to obtain the ranges to these landmarks. The main contribution of the paper is the formulation of the mathematical framework for SLAM for a robot moving on a planar surface among landmarks distributed in three dimensional space. The paper also presents the results of experiments for optimal control conducted using a Pioneer robot and a Triclops stereo vision system. It is demonstrated that accurate robot and feature locations can be obtained using the proposed technique. © 2006 IEEE.
Vidal-Calleja, T, Davison, AJ, Andrade-Cetto, J & Murray, DW 1970, 'Active control for single camera SLAM', Proceedings 2006 IEEE International Conference on Robotics and Automation, 2006. ICRA 2006., 2006 IEEE International Conference on Robotics and Automation, 2006. ICRA 2006., IEEE, Orlando, FL, pp. 1930-1936.
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In this paper we consider a single hand-held camera performing SLAM at video rate with generic 6DOF motion. The aim is to optimise both the localisation of the sensor and building of the feature map by computing the most appropriate control actions or mo
Wang, D, Liu, D, Dissanayake, G & IEEE 1970, 'A Variable Speed Force Field method for multi-robot collaboration', 2006 IEEE/RSJ INTERNATIONAL CONFERENCE ON INTELLIGENT ROBOTS AND SYSTEMS, VOLS 1-12, IEEE/RSJ International Conference on Robots and Intelligent Systems, IEEE, Beijing, China, pp. 2697-2702.
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A novel Force Field (F2) method with variable speed for multi-robot motion planning and collaboration is presented in this paper. The basic concept of the F2 method is to generate a force field for every robot based on and continuously changing according to its status including traveling speed, dimension, priority, location and environmental factor, etc. The interactions among robots' force fields and obstacles provide a natural way for collision avoidance and collaboration while robots are on their way to goals. Previous F2 method assumes that robots travel with constant speeds and can react instantly to the resultant force to change their orientations. Starting from a problematic situation brought out by this hypothesis, this paper remedies the F2 method by taking robots' dynamics and kinematics characteristics into consideration. In the Variable Speed Force Field method (VSF2), a robot can change its own speed according to environment information and its own status. Simulations in a real indoor environment were carried out and demonstrated the feasibility and effectiveness of this method. © 2006 IEEE.
Wang, Z, Huang, S & Dissanayake, G 1970, 'Implementation issues and experimental evaluation of D-SLAM', Field and Service Robotics, International Conference on Field and Service Robotics, Springer-Verlag Berlin, Port Douglas, Australia, pp. 155-166.
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D-SLAM algorithm first described in [1] allows SLAM to be decoupled into solving a non-linear static estimation problem for mapping and a threedimensional estimation problem for localization. This paper presents a new version of the D-SLAM algorithm that uses an absolute map instead of a relative map as presented in [1]. One of the significant advantages of D-SLAM algorithm is its O(N) computational cost where N is the total number of features (landmarks). The theoretical foundations of D-SLAM together with implementation issues including data association, state recovery, and computational complexity are addressed in detail. Evaluation of the D-SLAM algorithm is provided using both real experimental data and simulations. © Springer-Verlag Berlin/Heidelberg 2006.