Dissanayake, G, Williams, SB, Durrant-Whyte, H & Bailey, T 2002, 'Map management for efficient simultaneous localization and mapping (SLAM)', Autonomous Robots, vol. 12, no. 3, pp. 267-286.
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Dissanayake, G, Williams, SB, Durrant-Whyte, H & Bailey, T 2002, 'Map management for efficient simultanneous localisation and map building (SLAM) problem', Autonomous Robots, vol. 12, no. N/A, pp. 265-286.
Furukawa, T & Dissanayake, G 2002, 'Parameter identification of autonomous vehicles using multi-objective optimization', Engineering Optimization, vol. 34, no. 4, pp. 369-395.
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In order to properly operate an autonomous vehicle navigation system, it is important that the vehicle and sensor models of the vehicle are defined by an accurate parameter set. This paper presents a technique for identifying parameters of an autonomous vehicle using multi-objective optimization, which enables the identification process without introducing additional parameters. A multi-objective optimization method has been further proposed to solve the optimization problem defined for the identification efficiently and promisingly. Results of numerical examples first show that the proposed optimization method can work well for various multi-objective optimization problems. Then, the proposed identification technique has been applied to the actual parameter identification of the autonomous vehicle developed by the authors, and an appropriate parameter set has been obtained.
Ji, JC & Leung, AYT 2002, 'Resonances of a non-linear s.d.o.f. system with two time-delays in linear feedback control', JOURNAL OF SOUND AND VIBRATION, vol. 253, no. 5, pp. 985-1000.
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The primary, superharmonic, and subharmonic resonances of a harmonically excited non-linear s.d.o.f. system with two distinct time-delays in the linear state feeback are studied. The two different time-delays are presented in the proportional feedback and the derivative feedback respectively. The method of multiple scales is utilized to obtain the first order approximation of response. The effect of the feedback gains and time-delays on the steady state responses of three types of resonances is investigated. It is found that a proper selection of the feedback gains and time-delays can enhance the control performance.
Kodagoda, KRS, Wijesoma, WS & Teoh, EK 2002, 'Fuzzy speed and steering control of an AGV', IEEE Transactions on Control Systems Technology, vol. 10, no. 1, pp. 112-120.
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he development of techniques for lateral and longitudinal control of vehicles has become an important and active research topic in the face of emerging markets for advanced autonomous guided vehicles (AGVs) and mobile robots. In this respect, there has been much literature published, although not so much on the actual performance of such controllers in a practical setting. The primary focus in this paper is on the development and actual implementation of intelligent and stable fuzzy proportional derivative-proportional integral (PD-PI) controllers for steering and speed control of an AGV. The AGV used in this study is an electrically powered golf car, suitably modified for autonomous navigation and control. The use of fuzzy logic for control law synthesis, among other things, facilitates the incorporation of control heuristics, while guaranteeing stability, uncoupling steering control from speed control and providing for easy incorporation of a braking controller. Through experimentation, the designed controllers are demonstrated to be insensitive to parametric uncertainty, load and parameter fluctuations and, most importantly, amenable to real-time implementation. The performance of the proposed uncoupled direct fuzzy PD/PI control schemes for this particular outdoor AGV is also compared against conventional proportional-integral-derivative (PID) controllers. Experimental results demonstrate that the proposed fuzzy logic controllers, which are synthesized from a variable structure systems viewpoint, also outperform conventional PID schemes, particularly in tracking accuracy, steady-state error, control chatter and robustness
Li, QS, Liu, DK, Leung, AYT, Zhang, N & Luo, QZ 2002, 'A multilevel genetic algorithm for the optimum design of structural control systems', International Journal for Numerical Methods in Engineering, vol. 55, no. 7, pp. 817-834.
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AbstractA multilevel genetic algorithm (MLGA) is proposed in this paper for solving the kind of optimization problems which are multilevel structures in nature and have features of mixed‐discrete design variables, multi‐modal and non‐continuous objective functions, etc. Firstly, the formulation of the mixed‐discrete multilevel optimization problems is presented. Secondly, the architecture and implementation of MLGA are described. Thirdly, the algorithm is applied to two multilevel optimization problems. The first one is a three‐level optimization problem in which the optimization of the number of actuators, the positions of actuators and the control parameters are considered in different levels. An actively controlled tall building subjected to strong wind action is considered to investigate the effectiveness of the proposed algorithm. The second application considers a combinatorial optimization problem in which the number and configuration of actuators are optimized simultaneously, an actively controlled building under earthquake excitations is adopted for this case study. Finally, some results and discussions about the application of the proposed algorithm are presented. Copyright © 2002 John Wiley & Sons, Ltd.
Luo, Q & Tong, L 2002, 'Exact static solutions to piezoelectric smart beams including peel stresses', International Journal of Solids and Structures, vol. 39, no. 18, pp. 4677-4695.
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Luo, Q & Tong, L 2002, 'Exact static solutions to piezoelectric smart beams including peel stresses. II. Numerical results, comparison and discussion', International Journal of Solids and Structures, vol. 39, no. 18, pp. 4697-4722.
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Tam, CM, Leung, AWT & Liu, DK 2002, 'Nonlinear Models for Predicting Hoisting Times of Tower Cranes', Journal of Computing in Civil Engineering, vol. 16, no. 1, pp. 76-81.
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Wijesoma, WS, Kodagoda, KRS & Teoh, EK 2002, 'Stable Fuzzy State Space Controller for Lateral Control of an AGV', The Journal of VLSI Signal Processing, vol. 32, no. 1/2, pp. 189-201.
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Zhang, N, Liu, DK, Jeyakumaran, JM & Villanueva, L 2002, 'Modelling of dynamic characteristics of an automatic transmission during shift changes', PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART I-JOURNAL OF SYSTEMS AND CONTROL ENGINEERING, vol. 216, no. I4, pp. 331-341.
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Zhang, N, Liu, DK, Jeyakumaran, JM & Villanueva, L 2002, 'Modelling of dynamic characteristics of an automatic transmission during shift changes', Proceedings of the Institution of Mechanical Engineers, Part I: Journal of Systems and Control Engineering, vol. 216, no. 4, pp. 331-341.
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This paper describes modelling of the transient dynamics of an automatic transmission during gear changes. A brief introduction to the automatic transmission system and the dynamic characteristics of the transmission components during the gear changes are presented. Then, detailed mathematical models of a four-speed automatic transmission manufactured by BTR Automotive, Australia, are developed. A mode description method is used to describe the transient shifting process and a modular structure of the transmission system, which consists of a torque converter module, geartrain module, hydraulic system module and modules of clutches and bands, is presented. As an application, the developed simulation system is applied to investigate the transient performance of the automatic transmission during the 1–2 shift process. The output torque profiles predicted by the model simulation correlate very well with the experimental data measured from vehicle tests.
Crowther, A, Zhang, N, Liu, D & Jeyakumaran, J 1970, 'A FINITE ELEMENT METHOD FOR DYNAMIC ANALYSIS OF AUTOMATIC TRANSMISSION GEAR SHIFTING', The Proceedings of the International Conference on Motion and Vibration Control, International Conference on Motion and Vibration Control, Japan Society of Mechanical Engineers, Saitama, Japan, pp. 514-519.
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Gu Fang & Dissanayake, G 1970, 'Time-optimal feedback control of a non-holonomic vehicle using neural networks', 7th International Conference on Control, Automation, Robotics and Vision, 2002. ICARCV 2002., ICARV 2002: The Seventh International Conference on Control, Automation, Robotics and Vision, Nanyang Technological Univ, pp. 1458-1463.
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This paper presents a minimum-time feedback controller for maneuvering a non-holonomic vehicle. A trajectory planning algorithm that generates minimum-time trajectories for moving a vehicle from an arbitrary starting location to the origin is presented. Trajectories generated are used to train a neural network that computes instantaneous velocity and steering commands as a function of the current vehicle state. The proposed strategy is illustrated by developing a neural network based controller for backing up a truck. Computer simulations are presented that demonstrates the effectiveness of the proposed technique in the presence of disturbances.
Halkon, B & Rothberg, S 1970, 'Comprehensive velocity sensitivity model for scanning and tracking laser vibrometry', Proceedings of SPIE - The International Society for Optical Engineering, 20th IMAC Conference on Structural Dynamics, SOC EXPERIMENTAL MECHANICS INC, LOS ANGELES, CA, pp. 1166-1170.
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Recent work set out a comprehensive analysis of the velocity sensed by a single laser vibrometer beam incident in an arbitrary direction on a target that is of substantial interest in engineering - a rotating shaft requiring three translational and three rotational co-ordinates to describe its vibratory motion fully. Six separate 'vibration sets', each a combination of motion parameters, appeared in the full expression for vibration velocity sensitivity and the difficulties associated with resolving individual vibration components within a complex motion were highlighted. One specific way in which the model has been extended is the subject of this paper. The scanning laser Doppler vibrometer has become an increasingly popular instrument especially for experimental modal analysis. Continuously scanning strategies, in which the laser beam orientation is a continuous function of time, have received considerable attention. Researchers have reported use of several different types of scan profile including a tracking profile in which the probe laser beam remains fixed on a single point on a target such as a rotating disc. When the velocity sensitivity model was originally reported, it was stated that it could be used with such applications and this is shown explicitly, for the first time, in this paper.
Halkon, B & Rothberg, SJ 1970, '<title>A comprehensive velocity sensitivity model for scanning and tracking laser Doppler vibrometry on rotating structures</title>', SPIE Proceedings, Fifth International Conference on Vibration Measurements by Laser Techniques, SPIE, ANCONA, ITALY, pp. 9-21.
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Recent work set out a comprehensive analysis of the velocity sensed by a single laser Doppler vibrometer beam incident in an arbitrary direction on a target that is of substantial interest in engineering - a rotating, shaft requiring three translational and three rotational co-ordinates to describe its vibratory motion fully. Six separate 'vibration sets', each a combination of motion parameters, appeared in the full expression for vibration velocity sensitivity and the difficulties associated with resolving individual vibration components within a complex motion were highlighted. The velocity sensitivity model can incorporate time dependent beam orientation and this is described in this paper with reference to scanning laser Doppler vibrometry. Continuously scanning strategies, in which the laser beam orientation is a continuous function of time, have recently received considerable attention, including a tracking profile in which the probe laser beam remains fixed on a single point on a target such as a rotating disc. Typically, one beam deflection mirror is driven using a cosine function whilst the other is driven with a sine function, resulting in a slightly elliptical beam trajectory. This and other more significant issues such as the effects of misalignment are easily accommodated in the velocity sensitivity model and a thorough analysis of their influence on the measured vibration signal is reported in this paper.
Huang, S & Lam, J 1970, 'Control of uncertain bilinear systems using linear controllers: Stability region estimation and controller design', Proceedings of the IEEE Conference on Decision and Control, IEEE, Las Vegas, Nevada, USA, pp. 662-667.
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This paper studies the problem of stability region estimation and controller design for uncertain bilinear systems when linear controllers are used. Iterative linear matrix inequality (ILMI) algorithms are presented to estimate the closed-loop stability region and design the controllers. No tuning of parameters is needed in the design methods. The design aims to optimize between the size of the stability region, damping of the state variables, and the feedback gain.
Huynh, BP 1970, 'Coat Thickness in Wire-Coating Process With Corrugated Die', Materials: Processing, Characterization and Modeling of Novel Nano-Engineered and Surface Engineered Materials, ASME 2002 International Mechanical Engineering Congress and Exposition, ASMEDC, pp. 19-32.
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Effects of die wall corrugation on coat thickness t in the wire-coating process are investigated numerically, using non-isothermal viscous fluids of a Newtonian type as coating material and a finite element method. Corrugation is assumed to be in the form of sine waves near die exit. It can be seen that shorter wavelength or larger wave amplitude depresses t, whereas higher Nahme-Griffith number Na increases it; however, the changes in t are only very small. t is also depressed slightly when die wall’s exit angle θ is large and negative; but in general it is insensitive to variation in θ when this is small. That t is only slightly affected by Na and θ is in stark contrast to extrudate’s swelling behaviour in simple extrusion through annular dies under comparable conditions. Furthermore, wire speed does not affect t over the ranges of Na value considered here. One interesting aspect relating to isothermal smooth-wall situation is that the ratio t/ΔR, ΔR being annular gap size, is nearly constant and equal to 0.5, independent of wire radius ratio Rwire/Rdie. This constancy is in contrast to the variation in coat thickness that results from a pure drag flow in the annulus.
Kirpitchenko, I, Zhang, N, Tchernykh, S & Liu, D 1970, 'DYNAMICS AND CONTROL OF GRINDING MACHINES', The Proceedings of the International Conference on Motion and Vibration Control, Japan Society of Mechanical Engineers, Saitama, Japan, pp. 1039-1044.
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Kodagoda, KRS, Wijesoma, WS & Balasuriya, AP 1970, 'Road curb and intersection detection using A 2D LMS', IEEE International Conference on Intelligent Robots and Systems, IEEE/RSJ International Conference on Intelligent Robots and Systems, IEEE, Switzerland, pp. 19-24.
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In most urban roads, and similar environments such as in theme parks, campus sites, industrial estates, science parks and the like, the painted lane markings that exist may not be easily discernible by CCD cameras due to poor lighting, bad weather conditions, and inadequate maintenance. An important feature of roads in such environments is the existence of pavements or curbs on either side defining the road boundaries. These curbs, which are mostly parallel to the road, can be hardnessed to extract useful features of the road for implementing autonomous navigation or driver assistance systems. However, extraction of the curb or road edge feature using vision image data is a very formidable task as the curb is not conspicuous in the vision image. To extract the curb using vision data requires extensive image processing, heuristics and very favorable ambient lighting. In our approach, road curbs are extracted speedily using range data provided by a 2D Laser range Measurement System (LMS). Experimental results are presented to demonstrate the viability, and effectiveness, of the proposed methodology and its robustness to different road configurations including road intersections.
Kodagoda, KRS, Wijesoma, WS & Balasuriya, AP 1970, 'Road feature extraction using a 2D LMS', 7th International Conference on Control, Automation, Robotics and Vision, 2002. ICARCV 2002., ICARV 2002: The Seventh International Conference on Control, Automation, Robotics and Vision, Nanyang Technological Univ, Singapore, pp. 453-458.
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In most urban roads, and similar environments such as in the theme parks, campus sites, industrial estates, science parks and the like, the painted lane markings that exist may not be easily discernible by CCD cameras due to poor lighting, bad weather conditions and inadequate maintenance. An important feature of roads in such environments is the existence of pavements or curbs on either side defining the road boundaries. These curbs, which are mostly parallel to the road, can be harnessed to extract useful features of the road for implementing autonomous navigation or driver assistance systems. However, extraction of the curb or road edge feature using vision image data is a difficult task as curbs are not conspicuous in the vision image. To extract the curb from a camera image requires extensive image processing, heuristics and very favorable lighting. In our approach, road curbs are extracted speedily using range data provided by a 2D laser measurement system (LMS). Experimental results are presented to demonstrate the viability, and effectiveness, of the proposed methodology and its robustness to different obstacle, weather and lighting conditions.
Leal, J, Scheding, S, Dissanayake, G, IEEE, IEEE & IEEE 1970, 'Stochastic simulation in surface reconstruction and application to 3D mapping', 2002 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION, VOLS I-IV, PROCEEDINGS, IEEE International Conference on Robots and Automation, Institute of Electrical and Electronic Engineering, Washington DC,USA, pp. 1765-1770.
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Three dimensional terrain maps are useful representations of environments for various robotic applications. Unfortunately, sensor data (from which such maps are built) is uncertain and contains errors which are usually not accounted for in existing terrain building algorithms. In real-time applications, it is necessary to quantify these uncertainties to allow map construction decisions to be made online. This paper addresses this issue by providing a representation that explicitly accounts for sensing uncertainty. This is achieved through the use of stochastic simulation techniques. The result is in an algorithm for online 3D multiresolution surface reconstruction of unknown, and unstructured environments. Results of the surface reconstruction algorithm in a real environment are presented.
Liu, D, Zhang, N, Brown, TA & Tam, C 1970, 'A Multilevel Hybrid Genetic Algorithm For Structural Control System Optimization', Proc. of the 6th Int. Conference on Motion and Vibration Control, International Conference on Motion and Vibration Control, JSME, Saitama, Japan, pp. 154-159.
LIU, DK, ZHANG, N, JEYAKUMARAN, JM & VILLANUEVA, L 1970, 'TRANSIENT CHARACTERISTICS OF AN AUTOMATIC TRANSMISSION DURING SHIFT CHANGES', Applied Mechanics, Proceedings of the Third Australasian Congress on Applied Mechanics, WORLD SCIENTIFIC, Sydney, Australia, pp. 683-688.
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LUO, Q & TONG, L 1970, 'A FINITE ELEMENT ANALYSIS FOR PIEZOELECTRIC SMART PLATES INCLUDING PEEL STRESSES', Recent Advances in Computational Science and Engineering, Proceedings of the International Conference on Scientific and Engineering Computation (IC-SEC) 2002, PUBLISHED BY IMPERIAL COLLEGE PRESS AND DISTRIBUTED BY WORLD SCIENTIFIC PUBLISHING CO..
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LUO, Q & TONG, L 1970, 'PEELING EFFECTS ON PERFORMANCE OF PIEZOELECTRIC ACTUATORS AND SENSORS IN SMART BEAMS', Applied Mechanics, Proceedings of the Third Australasian Congress on Applied Mechanics, WORLD SCIENTIFIC.
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Madhavan, R, Durrant-Whyte, H, Dissanayake, G, IEEE, IEEE & IEEE 1970, 'Natural landmark-based autonomous navigation using curvature scale space', 2002 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION, VOLS I-IV, PROCEEDINGS, IEEE International Conference on Robots and Automation, Institute of Electrical and Electronic Engineering, Washington DC,USA, pp. 3936-3941.
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The paper describes a terrain-aided navigation system that employs points of maximum curvature extracted from laser scan data as primary landmarks. A scale space method is used to extract points of maximum curvature from laser range scans of unmodified outdoor environments. This information is then fused with odometric information to provide localization information for an outdoor vehicle. The method described is invariant to the size and orientation of the range images under consideration (with respect to rotation and translation), is robust to noise, and can reliably detect and localize naturally occurring landmarks in the operating environment. The algorithm is demonstrated in the application of a road vehicle in an unmodified operating domain.
Wang, M, Zhang, N, Chapman, C, Brown, T & Jeyakumaran, JM 1970, 'Design and torsional vibration analysis of a complex vehicle powertrain system test rig', PROCEEDINGS OF THE 5TH INTERNATIONAL CONFERENCE ON VIBRATION ENGINEERING, International Conference on Vibration Engineering, CHINA AVIATION INDUSTRY PRESS, NANJING, PEOPLES R CHINA, pp. 303-309.
Wijesoma, WS, Kodagoda, KRS & Balasuriya, AP 1970, 'A laser and a camera for mobile robot navigation', 7th International Conference on Control, Automation, Robotics and Vision, 2002. ICARCV 2002., ICARV 2002: The Seventh International Conference on Control, Automation, Robotics and Vision, Nanyang Technological Univ, Singapore, pp. 740-745.
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In most urban roads, and similar environments such as in theme parks, campus sites, industrial estates, science parks and the like, the painted lane markings that exist may not be easily discernible by CCD cameras due to poor lighting, bad weather conditions, and inadequate maintenance. An important feature of roads in such environments is the existence of pavements or curbs on either side defining the road boundaries. These curbs, which are mostly parallel to the road, can be harnessed to extract useful features of the road for implementing autonomous navigation or driver assistance systems. However, extraction of the curb or road edge feature using vision image data is a very formidable task as the curb is not conspicuous in the vision image. To extract the curb using vision data requires extensive image processing, heuristics and very favourable ambient lighting. In our approach, the curb data is extracted speedily using range data provided by a 2D laser range measurement device. This information is then used to extract the mid-line(s) in the vision image using an extended Kalman filtering (EKF) approach. Subsequently midline data is used for the prediction of the road boundaries. Experimental results are presented to demonstrate the viability, and effectiveness, of the proposed methodology.
Wijesoma, WS, Kodagoda, KRS & Balasuriya, AP 1970, 'Laser and vision sensing for road detection and reconstruction', Proceedings. The IEEE 5th International Conference on Intelligent Transportation Systems, IEEE 5th International Conference on Intelligent Transportation Systems., IEEE, Singapore, pp. 248-253.
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In most urban roads, and similar environments such as in theme parks, campus sites, industrial estates, science parks and the like, the painted lane markings that exist may not be easily discernible by CCD cameras due to poor lighting, bad weather conditions, and inadequate maintenance. An important feature of roads in such environments is the existence of pavements or curbs on either side defining the road boundaries. These curbs, which are mostly parallel to the road, can be harnessed to extract useful features of the road for implementing autonomous navigation or driver assistance systems. However, extraction of the curb or road edge feature using vision image data is a very formidable task as the curb is not conspicuous in the vision image. To extract the curb using vision data requires extensive image processing, heuristics and very favorable ambient lighting. In our approach, the curb data is extracted speedily rising range data provided by a 2D laser range measuring device. This information is then used to extract the mid-line(s) in the vision image using an extended Kalman filtering approach. Subsequently, midline data is used for the prediction of the road boundaries. Experimental results are presented to demonstrate the viability and effectiveness of the proposed methodology.
Williams, SB, Dissanayake, G, Durrant-Whyte, H, IEEE, IEEE & IEEE 1970, 'An efficient approach to the Simultaneous Localisation and Mapping problem', 2002 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION, VOLS I-IV, PROCEEDINGS, IEEE International Conference on Robots and Automation, Institute of Electrical and Electronic Engineering, Washington DC,USA, pp. 406-411.
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This paper presents a novel approach to the Simultaneous Localisation and Mapping (SLAM) algorithm that exploits the manner in which observations are fused into the global map of the environment to manage the computational complexity of the algorithm and improve the data association process. Rather than incorporating every observation directly into the global map of the environment, the Constrained Local Submap Filter (CLSF) relies on creating an independent, local submap of the features in the immediate vicinity of the vehicle. This local submap is then periodically fused into the global map of the environment using appropriately formulated constraints between the common feature estimates. This approach is shown to be effective in reducing the computational complexity of maintaining the global map estimates as well as improving the data association process.
Williams, SB, Dissanayake, G, Durrant-Whyte, H, IEEE, IEEE & IEEE 1970, 'Towards multi-vehicle simultaneous localisation and mapping', 2002 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION, VOLS I-IV, PROCEEDINGS, IEEE International Conference on Robots and Automation, Institute of Electrical and Electronic Engineering, Washington DC,USA, pp. 2743-2748.
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This paper presents a novel approach to the multi-vehicle simultaneous localisation and mapping (SLAM) problem that exploits the manner in which observations are fused into the global map of the environment to manage the computational complexity of the algorithm and improve the data association process. Rather than incorporating every observation directly into the global map of the environment, the constrained local submap filter (CLSF) relies on creating an independent, local submap of the features in the immediate vicinity of the vehicle. This local submap is then periodically fused into the global map of the environment. This representation is shown to reduce the computational complexity of maintaining the global map estimates as well as improving the data association process. This paper examines the prospect of applying the CLSF algorithm to the multi-vehicle SLAM problem
