Abdallah, ME & Waldron, KJ 2009, 'The mechanics of biped running and a stable control strategy', Robotica, vol. 27, no. 05, pp. 789-789.
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Huang, S, Wang, Z, Dissanayake, G & Frese, U 2009, 'Iterated D-SLAM map joining: evaluating its performance in terms of consistency, accuracy and efficiency', AUTONOMOUS ROBOTS, vol. 27, no. 4, pp. 409-429.
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This paper presents a new map joining algorithm and a set of metrics for evaluating the performance of mapping techniques. The input to the new map joining algorithm is a sequence of local maps containing the feature positions and the final robot pose in a local frame of reference. The output is a global map containing the global positions of all the features but without any robot poses. The algorithm is built on the D-SLAM mapping algorithm (Wang et al. in Int. J. Robot. Res. 26(2):187-204, 2007) and uses iterations to improve the estimates in the map joining step. So it is called Iterated D-SLAM Map Joining (I-DMJ). When joining maps I-DMJ ignores the odometry information connecting successive maps. This is the key to I-DMJ efficiency, because it makes both the information matrix exactly sparse and the size of the state vector bounded by the number of features. The paper proposes metrics for quantifying the performance of different mapping algorithms focusing on evaluating their consistency, accuracy and efficiency. The I-DMJ algorithm and a number of existing SLAM algorithms are evaluated using the proposed metrics. The simulation data sets and a preprocessed Victoria Park data set used in this paper are made available to enable interested researchers to compare their mapping algorithms with I-DMJ. © 2009 Springer Science+Business Media, LLC.
Kirchner, N, Liu, D & Dissanayake, G 2009, 'Surface Type Classification With a Laser Range Finder', IEEE SENSORS JOURNAL, vol. 9, no. 9, pp. 1160-1168.
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This paper presents a system for surface classification using a laser range finder. It is shown that the return intensities and range errors provide sufficient information to distinguish a wide range of surfaces commonly found in a number of environments. A supervised learning scheme (using curves representing the return intensity and range error as a function of angle of incidence) is used to classify the surface type of planar patches. Extensive experimental evidence is presented to demonstrate the potential of the proposed technique. The surface type classification, which uses a typical laser range finder, is targeted for use with autonomous robotic systems in which significantly different interaction is required for each of the various materials present. Results from an on-site experiment demonstrate that the information from the laser range finder is sufficient to identify the different materials (via their surface properties) present in a scene where a bridge structure is being prepared for grit blasting. © 2009 IEEE.
Kwok, NM, Ha, QP, Liu, D & Fang, G 2009, 'Contrast Enhancement and Intensity Preservation for Gray-Level Images Using Multiobjective Particle Swarm Optimization', IEEE TRANSACTIONS ON AUTOMATION SCIENCE AND ENGINEERING, vol. 6, no. 1, pp. 145-155.
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The contrast enhancement of gray-level digital images is considered in this paper. In particular, the mean image intensity is preserved while the contrast is enhanced. This provides better viewing consistence and effectiveness. The contrast enhancement is achieved by maximizing the information content carried in the image via a continuous intensity transform function. The preservation of image intensity is obtained by applying gamma-correction on the images. Since there is always a trade-off between the requirements for the enhancement of contrast and preservation of intensity, an improved multiobjective particle swarm optimization procedure is proposed to resolve this contradiction, making use of its flexible algorithmic structure. The effectiveness of the proposed approach is illustrated by a number of images including the benchmarks and an image sequence captured from a mobile robot in an indoor environment. © 2006 IEEE.
Lindsay, ED, Murray, S, Liu, DK, Lowe, DB & Bright, CG 2009, 'Establishment reality vs. maintenance reality: how real is real enough?', European Journal of Engineering Education, vol. 34, no. 3, pp. 229-234.
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Remote and virtual laboratories are increasingly prevalent alternatives to the face-to-face laboratory experience; however, the question of their learning outcomes is yet to be fully investigated. There are many presumptions regarding the effectiveness of these approaches; foremost amongst these assumptions is that the experience must be 'real' to be effective. Embedding reality into a remote or virtual laboratory can be an expensive and time-consuming task. Significant efforts have been expended to create 3D VRML models of laboratory equipment, allowing students to pan, zoom and tilt their perspective as they see fit. Multiple camera angles have been embedded into remote interfaces to provide an increased sense of 'realness'. This paper draws upon the literature in the field to show that the necessary threshold for reality varies depending upon how the students are interacting with the equipment. There is one threshold for when they first interact - the establishment reality - which allows the students to familiarise themselves with the laboratory equipment, and to build their mental model of the experience. There is, however, a second, lower, threshold - the maintenance reality - that is necessary for the students' ongoing operation of the equipment. Students' usage patterns rely upon a limited subset of the available functionality, focusing upon only some aspects of the reality that has been originally established. The two threshold model presented in this paper provides a new insight for the development of virtual laboratories in the future.
Lowe, D, Murray, S, Lindsay, E & Liu, D 2009, 'Evolving Remote Laboratory Architectures to Leverage Emerging Internet Technologies', IEEE TRANSACTIONS ON LEARNING TECHNOLOGIES, vol. 2, no. 4, pp. 289-294.
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There is growing research into, and development of, the use of the internet to support remote access by students to physical laboratory infrastructure. These remote laboratories can, under appropriate circumstances, support or even replace traditional (proximal) laboratories, provide additional or improved access at reduced cost, and encourage interinstitutional sharing of expensive resources. Effective design of remote laboratories requires attention to the design of both the pedagogy and the technical infrastructure, as well as how these elements interact. In this paper, we consider the architectures of remote laboratories, the shortcomings of existing implementations, and we argue that emerging internet technologies can assist in overcoming these shortcomings. We also consider the opportunities which these technologies provide in moving beyond both existing remote laboratories and existing proximal laboratories, to create opportunities which were not previously possible. © 2009 IEEE.
Paul, G, Liu, D, Kirchner, N & Dissanayake, G 2009, 'An Effective Exploration Approach to Simultaneous Mapping and Surface Material-Type Identification of Complex Three-Dimensional Environments', JOURNAL OF FIELD ROBOTICS, vol. 26, no. 11-12, pp. 915-933.
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This paper presents an integrated exploration approach for geometric mapping and surface material-type identification of complex three-dimensional (3D) environments using a six-degree-of-freedom industrial robot manipulator. Maps of the surface geometry with the surface material type identified are required for an autonomous robotic system to perform operations in steel bridge maintenance. The proposed approach utilizes information theory to enable multiobjective exploration while new 3D geometric and surface-type data are fused via probabilistic updates. It is verified that the integrated approach enables the robotic system to perform exploration and surface inspection in real-world environments. © 2009 Wiley Periodicals, Inc.
Pedraza, L, Rodriguez-Losada, D, Matia, F, Dissanayake, G & Valls Miro, J 2009, 'Extending the Limits of Feature-Based SLAM With B-Splines', IEEE TRANSACTIONS ON ROBOTICS, vol. 25, no. 2, pp. 353-366.
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This paper describes a simultaneous localization and mapping (SLAM) algorithm for use in unstructured environments that is effective regardless of the geometric complexity of the environment. Features are described using B-splines as modeling tool, and the set of control points defining their shape is used to form a complete and compact description of the environment, thus making it feasible to use an extended Kalman-filter (EKF) based SLAM algorithm. This method is the first known EKF-SLAM implementation capable of describing general free-form features in a parametric manner. Efficient strategies for computing the relevant Jacobians, perform data association, initialization, and map enlargement are presented. The algorithms are evaluated for accuracy and consistency using computer simulations, and for effectiveness using experimental data gathered from different real environments. © 2009 IEEE.
Sankaran, S, Hou Tay, B & Orr, M 2009, 'Managing organizational change by using soft systems thinking in action research projects', International Journal of Managing Projects in Business, vol. 2, no. 2, pp. 179-197.
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PurposeThis paper aims to show how systems thinking can be incorporated in action research (AR) interventions to successfully implement organizational change. The two case studies described in this paper would be useful to managers who want to implement change in their own organizations.Design/methodology/approachBoth projects used AR as the methodology due to its flexible, responsive and emergent nature. In one project, there was a deliberate attempt to incorporate soft systems thinking whereas in the other project soft systems thinking was used as a sense‐making process while carrying out AR. As an added benefit both approaches have resulted in successful completion of doctoral research.FindingsSoft systems methodology (SSM) and AR can both help in addressing ill‐structured problems faced by managers, in collaboration with stakeholders using questioning and reflection. Both lead to an increased understanding about the problem situation. The difference is that SSM uses a more structured approach while AR is emergent in its application. SSM practitioners advocate that action researchers would benefit by declaring in advance an intellectual framework to guide their research. This has the additional benefit of overcoming obstacles in an academic environment where research processes are still governed based on traditional research methods.Practical implicationsThe ideas presented in the paper could be particularly useful to a practice‐based discipline such as project management where research into its practice is in demand.Origina...
Shuhong Wang, Xiangjun Meng, Ningning Guo, Haibo Li, Jie Qiu, Jian Guo Zhu, Youguang Guo, Dikai Liu, Yi Wang & Wei Xu 2009, 'Multilevel Optimization for Surface Mounted PM Machine Incorporating With FEM', IEEE Transactions on Magnetics, vol. 45, no. 10, pp. 4700-4703.
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In this paper, Multilevel Genetic Algorithm (MLGA) is presented to solve the optimization of surface mounted permanent magnet synchronous machine (SPMSM), which has features of mixed continuous and discrete design variables, multi-modal objective functions, etc. Firstly, the multilevel optimization problem is described by using the problem matrix. The values in the problem matrix are deduced by correlation analysis. Secondly, the architecture and implementation of MLGA are carried out. Thirdly, the new algorithm is applied to a bilevel optimization of SPMSM to verify this multilevel optimization. The results compared with those of traditional genetic algorithm (GA) and discussions of the multilevel optimization are presented. © 2009 IEEE.
Sprinkle, J, Eklund, JM, Gonzalez, H, Grotli, EI, Upcroft, B, Makarenko, A, Uther, W, Moser, M, Fitch, R, Durrant-Whyte, H & Sastry, SS 2009, 'Model-based design: a report from the trenches of the DARPA Urban Challenge', SOFTWARE AND SYSTEMS MODELING, vol. 8, no. 4, pp. 551-566.
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To, WK, Paul, G, Kwok, NM & Liu, D 2009, 'An efficient trajectory planning approach for autonomous robots in complex bridge environments', International Journal of Computer Aided Engineering and Technology, vol. 1, no. 2, pp. 185-185.
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This paper presents an efficient trajectory planning approach for a 6DOF robotic manipulator conducting grit-blasting in complex bridge structural environments. The proposed approach extends upon robotic grit-blasting planning and incorporates joint movement minimisation in addition to path length minimisation. A genetic algorithm is implemented to optimise initial path plans based on a heuristic pattern for the coverage of surface areas to be blasted. A customised gradient based method is applied for the generation of collision-free joint configurations for grit-blasting based on the identified path plan. A grit-blasting coverage model is developed for discrete non-planar 3D coverage determination to verify the performance of the plan. Extensive simulation and experimental results are also presented in this paper. © 2009 Inderscience Enterprises Ltd.
Waldron, KJ, Estremera, J, Csonka, PJ & Singh, SPN 2009, 'Analyzing Bounding and Galloping Using Simple Models', Journal of Mechanisms and Robotics, vol. 1, no. 1.
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This paper focuses on modeling the gait characteristics of a quadrupedal gallop. There have been a number of studies of the mechanics of the stance phase in which a foot is in contact with the ground. We seek to put these studies in the context of the stride, or overall motion cycle. The model used is theoretical, and is kept simple in the interest of transparency. It is compared to empirical data from observations of animals, and to data from experiments with robots such as our KOLT machine, and results from sophisticated simulation studies. Modeling of the energy loss inherent in the interaction between the system and the environment plays a key role in the study. Results include the discovery of a hidden symmetry in the gait pattern, usually regarded as being completely asymmetrical. Another result demonstrates that the velocities with which the two front feet impact and leave the ground are different, and similarly for the rear feet. The velocities of the foot pairs mirror each other. This is consistent with empirical observation, but is at variance with the assumption used almost universally when modeling stance. A further result elicits the importance of the pitch moment of inertia and other effects that make the mammalian architecture, in which the center of mass is closer to the shoulders than to the hips, beneficial..
Alempijevic, A, Kodagoda, S & Dissanayake, G 1970, 'Mutual Information Based Data Association', PROCEEDINGS OF THE 2009 FIFTH INTERNATIONAL CONFERENCE ON INTELLIGENT SENSORS, SENSOR NETWORKS AND INFORMATION PROCESSING, Conference on Novel Optical Systems Design and Optimization XIII, IEEE, San Diego, CA, pp. 97-102.
Alempijevic, A, Kodagoda, S, Dissanayake, G & IEEE 1970, 'Cross-Modal Localization Through Mutual Information', 2009 IEEE-RSJ INTERNATIONAL CONFERENCE ON INTELLIGENT ROBOTS AND SYSTEMS, International Conference on Intelligent Robots and Systems, IEEE, St Louis, Missouri, pp. 5597-5602.
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Relating information originating from disparate sensors observing a given scene is a challenging task, particularly when an appropriate model of the environment or the behaviour of any particular object within it is not available. One possible strategy to address this task is to examine whether the sensor outputs contain information which can be attributed to a common cause. In this paper, we present an approach to localise this embedded common information through an indirect method of estimating mutual information between all signal sources. Ability of L1 regularization to enforce sparseness of the solution is exploited to identify a subset of signals that are related to each other, from among a large number of sensor outputs. As opposed to the conventional L2 regularization, the proposed method leads to faster convergence with much reduced spurious associations. Simulation and experimental results are presented to validate the findings. © 2009 IEEE.
Alempijevic, A, Kodagoda, S, Dissanayake, G & IEEE 1970, 'Mutual Information Based Data Association', 2009 INTERNATIONAL CONFERENCE ON INTELLIGENT SENSORS, SENSOR NETWORKS AND INFORMATION PROCESSING (ISSNIP 2009), International Conference on Intelligent Sensors, Sensor Networks and Information Processing, IEEE, Melbourne, Australia, pp. 97-102.
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Relating information originating from disparate sensors without any attempt to model the environment or the behaviour of any particular object within it is a challenging task. Inspired by human perception, the focus of this paper will be on observing objects moving in space using sensors that operate based on different physical principles and the fact that motion has in principle, greater power to specify properties of an object than purely spatial information captured as a single observation in time. The contribution of this paper include the development of a novel strategy for detecting a set of signals that are statistically dependent and correspond to each other related by a common cause. Mutual Information is proposed as a measure of statistical dependence. The algorithm is evaluated through simulations and three application domains, which includes, (1.) Grouping problem in images, (2.) Data association problem in moving observers with dynamic targets, and (3.) Multi-modal sensor fusion. © 2009 IEEE.
Beck, C, Miro, JV, Dissanayake, G & IEEE 1970, 'Trajectory Optimisation for Increased Stability of Mobile Robots Operating in Uneven Terrains', 2009 IEEE INTERNATIONAL CONFERENCE ON CONTROL AND AUTOMATION, VOLS 1-3, IEEE International Conference on Control and Automation, IEEE, Christchurch, NZ, pp. 1913-1919.
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A mechanism capable of enhancing the safety of paths followed by mobile robots which significantly modify their mass distribution while operating in uneven terrains is presented. This is the case, for instance, of kinematically reconfigurable platforms or robots equipped with manipulator arms. For a given path, a trajectory optimiser that finds suitably 'safer' paths in terms of tip-over prevention and equal force distribution over the supporting contact points is proposed. Other kinematic considerations such as operating within given nominal joint positions or low energy motions can also be exploited to improve system stability while being deployed in specific domains such as security, rescue, etc. Simulation results of the proposed optimised motion planner for an iRobot Explorer tracked vehicle are presented. They are also compared with a non-optimised planners to show the validity of the approach. ©2009 IEEE.
Boydell, S, Watson, N, Mangioni, V, McMillan, MD & Sankaran, S 1970, 'The Republic and its impact on property rights in Sydney', State of Australian Cities (SOAC) Conference, State of Australian Cities Conference, SOAC, Perth, Australia, pp. 1-21.
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In 1973, the Federal Commission of Inquiry into Land Tenures identified that `in our modern complex society, an individualistic approach to property rights and land ownership is incompatible with public interest, unless individual rights are restricted to the use and enjoyment of the land (Else-Mitchell et al., 1973, p.17). We offer a theoretical inquiry into the institutional arrangements to enable an innovative land restitution model for Sydney within a new Republic, by vesting the superior interest in land (and buildings thereon) in the stewardship of the customary indigenous guardians (rather than the State or Crown). The model analyses leasehold solutions and land tax implications to ensure the continued economic growth of the City of Sydney under such a restitution arrangement.
Brooks, PA, Manamperi, P, Liu, D & Dissanayake, G 1970, 'A robotic grit-blasting system for steel bridge maintenance', The 2009 Australasian Corrosion Association (ACA) conference, 15-18 November 2009,, Coffs Harbour, NSW, Australia.
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Corrosion is the primary cause of failure in steel bridges. Stripping of rust and deteriorated paint and then repainting the steel are the procedures in steel bridge maintenance, and is one of the biggest expenditure items in bridge maintenance activities. Grit-blasting, which is an effective and efficient method of paint stripping, is extremely labour intensive and hazardous. Workers have to not only spend long periods of time handling forces of 100N and above, but also need to take precautions to avoid exposure to the dust containing hazardous materials and chemicals. Thus supplementing manual labour in grit-blasting with robotic aids has a significant health, safety and economic impact.
Cheong, CY, Tan, KC & Liu, DK 1970, 'Solving the berth allocation problem with service priority via multi-objective optimization', 2009 IEEE Symposium on Computational Intelligence in Scheduling, 2009 IEEE Symposium on Computational Intelligence in Scheduling (CI-Sched), IEEE, Sheraton Music City Hotel, Nashville, TN, USA, pp. 95-102.
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This paper studies a multi-objective instance of the berth allocation problem (BAP). The BAP involves the determination of exact berthing times and positions of incoming ships in a container port so as to minimize concurrently the three objectives of makespan of the port, total waiting time of the ships, and degree of deviation from a predetermined service priority schedule. These objectives represent the interests of both port and ship operators. Unlike most existing approaches in the literature which are singleobjective- based, a multi-objective evolutionary algorithm (MOEA) that incorporates the concept of Pareto optimality is proposed for solving the multi-objective BAP. The multiobjective approach reveals several interesting characteristics of the BAP.
Chotiprayanakul, P & Liu, DK 1970, 'Workspace mapping and force control for small haptic device based robot teleoperation', 2009 International Conference on Information and Automation, 2009 International Conference on Information and Automation (ICIA), IEEE, Zhuhai/Macau, China, pp. 1613-1618.
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When a large robot manipulator is remotely controlled by means of a small haptic device, there are two issues which should be addressed: mapping of robot arm workspace and haptic device workspace, and accurate and safe control of the movement of the robot arm. This paper presents a haptic device workspace spanning control method for haptic-based teleoperation. The spanning control method includes haptic-space scaling control, drift control and edge motion control. A force control algorithm is also presented to control the robot arm's motion in complex 3D environments. Experimental results demonstrate that the mapping method and the force control algorithm can remotely control a robot arm to rapidly reach target positions, minimize the oscillation of the haptic device handle, achieve accurate positioning and provide the operator with efficient touch sensing. © 2009 IEEE.
Chotiprayanakul, P & Liu, DK 1970, 'Workspace Mapping and Force Control for Small Haptic Device based Robot Teleoperation', ICIA: 2009 INTERNATIONAL CONFERENCE ON INFORMATION AND AUTOMATION, VOLS 1-3, IEEE International Conference on Information and Automation (ICIA 2009), IEEE, Zhuhai, PEOPLES R CHINA, pp. 1588-1593.
Fitch, R, Lal, R & IEEE 1970, 'Experiments with a ZigBee Wireless Communication System for Self-Reconfiguring Modular Robots', ICRA: 2009 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION, VOLS 1-7, IEEE International Conference on Robotics and Automation, IEEE, Kobe, JAPAN, pp. 3965-3970.
Haslett, T & Sankaran, S 1970, 'Applying multi-methodological systems theory to project management', 53rd Annual Conference of the International Society for the Systems Sciences 2009: Making Liveable, Sustainable Systems Unremarkable, pp. 824-835.
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This paper begins with the proposition that most project managers are dealing with complex systems. Complex systems are defined as systems with numerous stakeholders, nonlinearities, multiple interdependencies and feedback systems. Typical nonlinearities are often unanticipated changes in the scope of the project, the dismissal of project managers, shedding people with critical labour skills or the termination of credit arrangements with banks. The interdependencies are the relationships between project management, the suppliers and contractors, the clients and the other stakeholders. The feedback systems most common to the success and failure of project management are the rework cycles and their impact on both the demand for labour and the final budget and completion date. The paper outlines a methodology for project management that integrates a number of systems thinking tools into the project management process.
Hernandez-Gutierrez, A, Nieto, JI, Vidal-Calleja, T & Nebot, E 1970, 'Large scale visual odometry using stereo vision', Proceedings of the 2009 Australasian Conference on Robotics and Automation, ACRA 2009.
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This paper presents a system for egomotion estimation using a stereo head camera. The camera motion estimation is based on features tracked along a video sequence. The system also estimates the tridimensional geometry of the environment by fusing the visual information from multiple views. Furthermore, the paper presents comparisons between two different algorithms. The first one is by applying triangulation to 3D points. Motion estimation using 3D points suffers from the problem of nonisotropic noise due to the large uncertainty in depth estimation. To deal with this problem we present results with a second approach that works directly in the disparity space. Experimental results using a mobile platform are presented. The experiments cover long distances in urban-like environments with the presence of dynamic objects. The system presented is part of a bigger project involving autonomous navigation using vision only.
Hu, G, Huang, S, Dissanayake, G & IEEE 1970, '3D I-SLSJF: A Consistent Sparse Local Submap Joining Algorithm for Building Large-Scale 3D Map', PROCEEDINGS OF THE 48TH IEEE CONFERENCE ON DECISION AND CONTROL, 2009 HELD JOINTLY WITH THE 2009 28TH CHINESE CONTROL CONFERENCE (CDC/CCC 2009), IEEE Conference on Decision and Control, IEEE, Shanghai, China, pp. 6040-6045.
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This paper presents an efficient and reliable algorithm for autonomous robots to build large-scale three dimensional maps by combining small local submaps. The algorithm is a generalization of our recent work on two dimensional map joining algorithm - Iterated Sparse Local Submap Joining Filter (I-SLSJF). The 3D local submap joining problem is formulated as a least squares optimization problem and solved by Extended Information Filter (EIF) together with smoothing and iterations. The resulting information matrix is exactly sparse and this makes the algorithm efficient. The smoothing and iteration steps improve the accuracy and consistency of the estimate. The consistency and efficiency of 3D I-SLSJF is demonstrated by comparing the algorithm with some existing algorithms using computer simulations. ©2009 IEEE.
Kuo, V & Fitch, R 1970, 'Towards a parallel wireless radio communication architecture for modular robots', Proceedings of the 2009 Australasian Conference on Robotics and Automation, ACRA 2009.
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Provisioning a scalable communication architecture in self-reconfiguring (SR) modular robots is one of the major challenges in their large-scale implementation in hardware. The infrared and hardwired communication systems usually employed are complex, are unreliable, and can lead to unrecoverable errors. Wireless mesh networks offer a robust and versatile solution but do not scale in terms of bandwidth and latency. By exploiting the unique properties of modular robots, we address the scalability problem in this paper. We propose a novel multi-radio, multi-channel mesh network architecture that guarantees fixed bandwidth and latency for inter-module communication, independent of the robot size. We present experimental results using modified ZigBee radios in a well-controlled setup that is free from unpredictable properties of radio propagation such as multi-path interference. By eliminating variables that would otherwise be present in a practical environment, we are able to precisely validate the principles and assumptions of our architecture. Using results from our experiments as a baseline we also qualitatively show that our approach has in-built protection from multi-path interference.
Lal, R & Fitch, R 1970, 'A hardware-in-the-loop simulator for distributed robotics', Proceedings of the 2009 Australasian Conference on Robotics and Automation, ACRA 2009.
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Developing planning and control algorithms for distributed robotic systems involves implementing complex asynchronous algorithms on embedded hardware platforms with limited computational resources. The ability to efficiently validate such algorithms in hardware is critical, yet challenging due to their decentralised nature. We propose the use of hardware-in-the-loop simulation as an intermediate step to improve the process of performing such validation. We present the design and implementation of a custom hardware-in-the-loop simulator consisting of 27 embedded units with wireless communication and a special gateway device for interfacing with a desktop computer. We also present two case studies that illustrate the use and benefits of this system.
Liu, M, Huang, S & Dissanayake, G 1970, 'A new observation model for B-Spline SLAM', Proceedings of the 2009 Australasian Conference on Robotics and Automation, ACRA 2009, Australasian Conference on Robotics and Automation, Australian Robotics and Automation Association Inc., Sydney, Australia, pp. 1-8.
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Recently, a novel laser data based SLAM algorithm using B-Spline as features has been developed in [Pedraza et al., 2007]. EKF is used in the proposed BS-SLAM algorithm and the state vector contains the current robot pose together with the control oints of the splines. The obervation model used for the EKF update is the intersections of the laser beams with the splines contained in the map. In this paper, we propose a new observation model for B-Spline SLAM. By properly defining the control pointsfor the splines, the observation model can be expressed as a function of relative positions between control points and the robot pose, which is the same format as what used in point feature based SLAM. This new observation model make it possible to apply optimization based techniques to B-Spline SLAM, which has the potential to resolve the inconsistency issues of B-Spline SLAM.
Miro, JV, Osswald, V, Patel, M & Dissanayake, G 1970, 'Robotic assistance with attitude: A mobility agent for motor function rehabilitation and ambulation support', 2009 IEEE International Conference on Rehabilitation Robotics, the Community (ICORR), IEEE, Kyoto, Japan, pp. 529-534.
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This paper presents the design of an intelligent walking aid for the frail and elderly as well as for patients who are recovering from surgical procedures, in order to enhance safer mobility for these study populations. The device augments a conventional rolling walker aid with sensing and navigational abilities to safely travel through an environment following user's perceived intentions, unless collisions or instability is imminent. The agent, embodied as a Partially Observable Markov Decision Process (POMDP), critically relies on minimal user input to seamlessly recognise user's short-term intended behaviour, constantly updating this projection to allow for inconspicuous user-robot integration. This, in turn, shifts user's focus from fine motor-skilled control to coarse indications broadly intended to convey intention. Overall, the system can afford an increase in safety for the cognitive user through preventative care - reduced number of falls or collision with surrounding objects, minimising health-care expenses as well as increasing independent living for people with gait disorders. Successful simulation and experimental results demonstrate the validity of the proposed architecture for a practical robotic rollator design. ©2009 IEEE.
Miro, JV, Osswald, V, Patel, M & Dissanayake, G 1970, 'Robotic Assistance with Attitude: a Mobility Agent for Motor Function Rehabilitation and Ambulation Support', 2009 IEEE 11TH INTERNATIONAL CONFERENCE ON REHABILITATION ROBOTICS, VOLS 1 AND 2, 11th IEEE International Conference on Rehabilitation Robotics, IEEE, Kyoto, JAPAN, pp. 616-+.
Sehestedt, S, Kodagoda, S, Alempijevic, A & Dissanayake, G 1970, 'Efficient learning of motion patterns for robots', Proceedings of the 2009 Australasian Conference on Robotics and Automation, ACRA 2009, Australasian Conference on Robotics and Automation, Australian Robotics and Automation Association Inc., Sydney, Australia, pp. 1-7.
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In this work we present a novel approach to learning dynamics of an environment perceived by a mobile robot. More precisely, we are interested in general motion patterns occurring in the environment rather than object dependent ones. A sampling algorithm is used to update a sample set, which represents observed dynamics, using the Bayes rule. From this set of samples a Hidden Markov Model is learnt online, which allows fast and efficient matching and prediction in the learnt model. Such models are useful for a number of tasks such as path planning, localisation and compliant motion. The approach is validated through simulation as well as experiments.
Sola, J, Vidal-Calleja, T & Devy, M 1970, 'Undelayed initialization of line segments in monocular SLAM', 2009 IEEE/RSJ International Conference on Intelligent Robots and Systems, 2009 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS 2009), IEEE, St. Louis, MO, pp. 1553-1558.
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This paper presents 6-DOF monocular EKF-SLAM with undelayed initialization using linear landmarks with extensible endpoints, based on the Plücker parametriz-ation. A careful analysis of the properties of the Plücker coordinates, defined in the projective space ℙ5, permits their direct usage for undelayed initialization. Immediately after detection of a segment in the image, a Plücker line is incorporated in the map. A single Gaussian pdf includes inside its 2-sigma region all possible lines given the observed segment, from arbitrarily close up to the infinity range, and in any orientation. The lines converge to stable 3D configurations as the moving camera gathers observations from new viewpoints. The line's endpoints, maintained out of the map, are constantly retro-projected from the image onto the line's local reference frame. An extending-only policy is defined to update them. We validate the method via Monte Carlo simulations and with real imagery data. © 2009 IEEE.
To, AW, Paul, G, Kwok, N & Liu, D 1970, 'An integrated approach to planning for autonomous grit-blasting robot in complex bridge environments', Proceedings of 2008 Fourth I*PROMS Virtual Conference International Conference on Innovative Production Machines and Systems, International Conference on Innovative Production Machines and Systems, Whittles Publishing, Cardiff University, Wales, UK, pp. 313-318.
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This paper describes an integrated approach to robot manipulator path and motion planning in complex bridge environments. It incorporates grit-blasting specific considerations including blasting effect, coverage, path length and robot arm joint movement. A genetic algorithm is implemented for path planning with the use of environment data to increase planning efficiency. A customized gradient based method is applied in selecting collision free joint configurations for the identified path. A grit-blast coverage model is also developed for discrete non-planar 3D coverage determination to verify the performance of the planned path and motion.
Vidal-Calleja, TA, Berger, C & Lacroix, S 1970, 'Event-driven loop closure in multi-robot mapping', 2009 IEEE/RSJ International Conference on Intelligent Robots and Systems, 2009 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS 2009), IEEE, St Louis, MO, pp. 1535-1540.
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A large-scale mapping approach is combined with multiple robots events to achieve cooperative mapping. The mapping approach used is based on hierarchical SLAM global level and local maps, which is generalized for the multi-robot case. In particular, the
Wang, JJ, Hu, G, Huang, S & Dissanayake, G 1970, '3D landmarks extraction from a range imager data for SLAM', Proceedings of the 2009 Australasian Conference on Robotics and Automation, ACRA 2009, Australasian Conference on Robotics and Automation, Australian Robotics and Automation Association Inc., Sydney, Australia, pp. 1-8.
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This paper introduces a new 3D landmark extraction method using the range and intensity images captured by a single range camera. Speeded up robust features (SURF) detection and matching is used to extract and match features from the intensity images. The range image information is used to transfer the selected 2D features into 3D points. The range measurement bias and uncertainty of the range camera are analysed, and their models are developed for improving the range estimation. After outliers' detection and removal using random sampling consensus (RANSAC), reliable 3D points are obtained. 3D landmarks for simultaneous localisation and mapping (SLAM) are selected from the 3D points considering several factors, such as the uncertainty and geometry of their locations. Because of the availability of the SURF descriptor, the data association in SLAM has been performed using both the geometry and the descriptor information. The proposed method is tested in unstructured indoor environments, where the range camera moves in six degrees of freedom. Experimental results demonstrate the success of the proposed 3D landmark extraction method for SLAM.
Wang, JJ, Kodagoda, S & Dissanayake, G 1970, 'Vision aided GPS/INS system for robust land vehicle navigation', 22nd International Technical Meeting of the Satellite Division of the Institute of Navigation 2009, ION GNSS 2009, pp. 195-204.
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This paper introduces a new approach for improving land vehicle navigation by integrating a digital camera with a GNSS receiver and a MEMS INS, to provide seamless robust navigation solutions in urban environment. As a camera has the ability to detect surrounding environment, it can measure its relative position and direction to the surrounding objects. The integration of heterogeneous sensors with very different characters, such as GNSS, INS and image in this approach, can complement each other and provide cost-effective and robust navigation solutions. In the proposed system, INS is selected as the reference navigation sensor as it provides complete navigation solutions without disruptions. The navigation errors caused by its inherent nonlinear and time-varying characteristics can be corrected by the camera and GNSS. Vision based navigation (VBN) is one of the fundamental issues in computer vision and is relatively well developed. In this paper mono vision (MV) based navigation technologies are merged with GNSS and INS measurement, termed as GNSS/INS/MV (GlMV) integration. VBN is at the core of proposed robust navigation system, in which a relative range scale factor is estimated by continuously applying structure-from-motion in the MV navigation. Due to the complexity of multi-sensor integration, it needs an optimal sensor fusion framework with reliable system design, modeling and quality control procedures. The proposed sensor fusion method consists of two local and one master data fusion units, based on extended Kalman filter and fuzzy logic. It takes the advantages of federate architecture, and can select using either GNSS or VBN navigation solutions for PNS correction according to their quality. GNSS/INS integration is the mainstream for navigation when the vehicle travels in an open area with good GNSS signal. At the same time, the modeling parameters of INS and camera are estimated. When the system is navigating in areas with weak GNSS signals,...
Wang, JJ, Kodagoda, S, Dissanayake, G, Wang, J, Feng, Y & Wang, C 1970, 'Vision Aided GPS/INS System for Robust Land Vehicle Navigation', PROCEEDINGS OF THE 22ND INTERNATIONAL TECHNICAL MEETING OF THE SATELLITE DIVISION OF THE INSTITUTE OF NAVIGATION (ION GNSS 2009), 22nd Int. Tech. Meeting of the Satellite Division of the U.S. Inst. of Navigation, U.S. Inst. of Navigation, Savannah International Convention Center, Savannah, GA, US, pp. 600-609.
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: This paper introduces a new approach for improving land vehicle navigation by integrating a digital camera with a GNSS receiver and a MEMS INS, to provide seamless robust navigation solutions in urban environment. As a camera has the ability to detect surrounding environment, it can measure its relative position and direction to the surrounding objects. The integration of heterogeneous sensors with very different characters, such as GNSS, INS and image in this approach, can complement each other and provide cost-effective and robust navigation solutions. In the proposed system, INS is selected as the reference navigation sensor as it provides complete navigation solutions without disruptions. The navigation errors caused by its inherent nonlinear and time-varying characteristics can be corrected by the camera and GNSS. Vision based navigation (VBN) is one of the fundamental issues in computer vision and is relatively well developed. In this paper mono vision (MV) based navigation technologies are merged with GNSS and INS measurement, termed as GNSS/INS/MV (GIMV) integration. VBN is at the core of proposed robust navigation system, in which a relative range scale factor is estimated by continuously applying structure-from-motion in the MV navigation. Due to the complexity of multi-sensor integration, it needs an optimal sensor fusion framework with reliable system design, modeling and quality control procedures. The proposed sensor fusion method consists of two local and one master data fusion units, based on extended Kalman filter and fuzzy logic. It takes the advantages of federate architecture, and can select using either GNSS or VBN navigation solutions for INS correction according to their quality. GNSS/INS integration is the mainstream for navigation when the vehicle travels in an open area with good GNSS signal. At the same time, the modeling parameters of INS and camera are estimated. When the system is navigating in areas with weak GNSS signals, such as...
Yu, Y, Kodagoda, S & Ha, QP 1970, 'Relative Distance Estimation for Indoor Multi-Robot Control Using Monocular Digital Camera', Proceedings of the 3rd International Workshop on Artificial Intelligence in Science and Technology, International Workshop on Artificial Intelligence in Science and Technology, The University of Tasmania, Hobart, Australia, pp. 1-6.
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Distance measurement methodologies based on the digital camera usually require extensive calibration routines, some are even derived from complicated image processing algorithms resulting in low picture frame rates. Particularly, in a dynamic camera system, due to the unpredictability of intrinsic and extrinsic parameters, the reliable measuring results are highly dependent on the accuracy of extra sensors. In this paper, a simple algorithm for relative distance estimation is proposed for multi-robot control with a monocular digital camera. Reasonable accuracy is achieved by judging the 2D perspective projection image ratio (PPIR) of robots' labels on a TFT-LCD (Thin Film Transistor-Liquid Crystal Display) monitor without any additional sensory cost and complicated calibration effort. Further, the algorithm does not contain any trigonometric functions so that it can be easily implemented on an embedded system using the field programmable gate array (FPGA) technology.
Yuan, S, Huang, S, Liu, D, Lau, H, Pagac, D & Pratley, T 1970, 'Problem formulation of simultaneously dynamic scheduling and collision-free path planning for multiple autonomous vehicles in automated container terminals', International Symposium for Maritime Logistics and Supply Chain Systems, Singapore.
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This work is motivated by an actual application of dispatching and path planing for a fleet of autonomous straddle carriers operated by Patrick Stevedores at the fully automated container terminal located in Brisbane, Australia. In this application, the straddle carriers can localize themselves and navigate autonomously within in the seaport. They can also pick up, transport, and drop down the containers without any human interference. The container transportation tasks performed by the fully autonomous straddle carriers include moving containers from quay crane area to yard, from yard to quay crane area, from yard to yard, from truck area to yard and from yard to truck area.
Yuan, S, Lau, H, Liu, DK, Huang, SD, Dissanayake, G, Pagac, D & Pratley, T 1970, 'Simultaneous dynamic scheduling and collision-free path planning for multiple autonomous vehicles', 2009 International Conference on Information and Automation, 2009 International Conference on Information and Automation (ICIA), IEEE, Zhuhai/Macau, China, pp. 522-527.
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When autonomous vehicles are deployed to perform transportation tasks within a confined space and strict time constraint, the problem of optimizing the assignment of tasks to vehicles is complicated by the need to ensure safety (they do not collide with or impede each other) and maximize the efficiency and productivity. With the increasing number of autonomous vehicles in practical settings, the ability to schedule tasks in a manner that inherently considers the effects of task allocations on space contention (which in turn compromises efficiency) is important to performance improvement. The main contribution of this paper is an approach to simultaneously conduct dynamic task allocation and collision-free path planning in an environment where multiple autonomous vehicles operate on a network of paths and where each path segment can only be occupied by one vehicle at a given instant. In particular, a generic algorithm for effective task allocation is investigated and applied in conjunction with an application-specific objective function. The proposed approach is able to solve the dynamic scheduling, planning and collision avoidance problem in an integrated way such that the overall productivity of the transportation system is improved. Simulation results based on a real-world industrial material handling environment demonstrate the feasibility and effectiveness of the proposed method. © 2009 IEEE.
Yuan, S, Lau, H, Liu, DK, Huang, SD, Dissanayake, G, Pagac, D & Pratley, T 1970, 'Simultaneous Dynamic Scheduling and Collision-Free Path Planning for Multiple Autonomous Vehicles', ICIA: 2009 INTERNATIONAL CONFERENCE ON INFORMATION AND AUTOMATION, VOLS 1-3, IEEE International Conference on Information and Automation (ICIA 2009), IEEE, Zhuhai, PEOPLES R CHINA, pp. 507-+.