Publications

Clark, S. & Dissanayake, G. 1999, 'Simultaneous localisation and map building using millimetre wave radar to extract natural features', Proceedings - IEEE International Conference on Robotics and Automation, vol. 2, pp. 1316-1321.
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This paper discusses the use of a 77GHz millimetre wave radar as a guidance sensor for autonomous land vehicle navigation. An extended Kalman filter (EKF) maintains an estimate of map features in addition to vehicle state. This map augmented EKF is implemented with radar reflectors, designed for high visibility from all orientations. An improvement on this approach enables natural features to be identified, using the polarisation of returned radar signals. Those that are suitable as navigational markers are used to update estimates of vehicle and feature locations. This method requires no a priori knowledge of the environment and no target infrastructure.

Dissanayake, G., Sukkarieh, S., Nebot, E. & Durrant-Whyte, H. 1999, 'New algorithm for the alignment of inertial measurement units without external observation for land vehicle applications', Proceedings - IEEE International Conference on Robotics and Automation, vol. 3, pp. 2274-2279.
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This paper describes a real time, on-the-fly, Roll and Pitch alignment algorithm for Inertial Measurement Units (IMUs) mounted on land vehicles. Unlike conventional strategies, the alignment is achieved without external observations. This is achieved by exploiting the non-holonomic constraints that govern the motion of a vehicle on a surface to obtain the Roll and Pitch of the IMU. The position of the vehicle along its path is still unobservable and the algorithm is effective only when there is sufficient excitation in all degrees of freedom. However, with the proposed alignment algorithm, the IMU is able to provide sufficiently accurate position information for substantially longer periods of time compared with conventional methods. Experimental results are provided along with a comparison of an IMU/GPS navigation loop showing the effectiveness of the algorithm.

Huang, S. & Zhang, S. 1999, 'Some control problems for symmetric circulant composite systems', Kongzhi Lilun Yu Yingyong/Control Theory and Applications, vol. 16, no. 4.
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In this paper, we study the output regulation for symmetric circulant composite systems and the quadratic stability and the quadratic stabilization for uncertain symmetric circulant omposite systems. It is shown that because of the special structure of the system, the output regulator roblems for such a system can be transfered to the output regulator problem for sys tems with lower rder. The quadratic stability for such a system can be simplified by considering the quadratic stability of several independent systems of lower order. And the quadratic stabilization controller of such a system can be constructed by the quadratic stabilization controller of systems with lower order.

Huang, S., Lam, J., Yang, G.H. & Zhang, S. 1999, 'Fault tolerant decentralized H∞ control for symmetric composite systems', IEEE Transactions on Automatic Control, vol. 44, no. 11, pp. 2108-2114.
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This note discusses a class of large-scale systems composed of symmetrically interconnected identical subsystems. We consider the decentralized H ∞ control design problem and study the fault tolerance of the resulting system. By exploiting the special structure of the systems, a sufficient condition for the existence of a decentralized H ∞ controller is derived. Moreover, for the nominal case as well as for contingent situations characterized by control channel failures, the poles and the H ∞ -norm of the closed-loop system can be calculated easily based on certain systems of reduced dimensions. Consequently, the tolerance to actuator failure can be easily tested.

Madhavan, R., Dissanayake, G., Durrant-Whyte, H., Roberts, J., Corke, P. & Cunningham, J. 1999, 'Issues in autonomous navigation of underground vehicles', Mineral Resources Engineering, vol. 8, no. 3, pp. 313-324.
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This paper describes current research at the Australian Centre for Field Robotics (ACFR) in collaboration with the Commonwealth Scientific and Industrial Research Organisation (CSIRO) within the Cooperative Research Centre (CRC) for Mining Technology and Equipment (CMTE) towards achieving autonomous navigation of underground vehicles, like a Load-Haul-Dump (LHD) truck. This work is being sponsored by the mining industry through the Australian Mineral Industries Research Association Limited (AMIRA). Robust and reliable autonomous navigation can only be realised by achieving high level tasks such as path-planning and obstacle avoidance. This requires determining the pose (position and orientation) of the vehicle at all times. A minimal infrastructure localisation algorithm that has been developed for this purpose is outlined and the corresponding results are presented. Further research issues that are under investigation are also outlined briefly.

Madhavan, R., Nettleton, E., Nebot, E., Dissanayake, G., Cunningham, J., Durrant-Whyte, H., Corke, P. & Roberts, J. 1999, 'Evaluation of internal navigation sensor suites for underground mining vehicle navigation', Proceedings - IEEE International Conference on Robotics and Automation, vol. 2, pp. 999-1004.
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This paper describes a series of trials that were done at an underground mine in New South Wales, Australia. Experimental results are presented from the data obtained during the field trials and suitable sensor suites are evaluated.

Scheding, S., Dissanayake, G., Nebot, E. & Durrant-Whyte, H. 1999, 'An Experiment In Autonomous Navigation Of An Underground Mining Vehicle', IEEE Transactions On Robotics And Automation, vol. 15, no. 1, pp. 85-95.
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This paper describes the theoretical development and experimental evaluation of a navigation system for an autonomous load, haul, and dump truck (LHD) based on the results obtained during extensive in-situ field trials. The particular contributions of th

Schmiedeler, J.P. & Waldron, K. 1999, 'The Mechanics Of Quadrupedal Galloping And The Future Of Legged Vehicles', International Journal Of Robotics Research, vol. 18, no. 12, pp. 1224-1234.
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Previous studies have noted that biological quadrupeds adjust their gaits when encountering drag in their locomotion. This paper investigates the hypothesis that these gait adjustments allow the legs to operate at an optimal working length when generatin

Waldron, K. 1999, 'Drafting A New Plan For Design', Mechanical Engineering, pp. 37-38.
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Wang, J. 1999, 'Mending Broken Handwriting with a Macrostructure Analysis Method to Improve Recognition', Pattern Recognition Letters, vol. 20, no. 8, pp. 855-864.
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Abstract: Broken characters always create problems in handwriting recognition systems, especially those using boundary and/or skeleton information. This paper presents a macrostructure analysis (MSA) mending method based on skeleton and boundary information and an MSA that investigates the stroke tending direction and other properties of handwritings. A new skeleton end extension algorithm is introduced, which compensates the defectiveness of the skeletonization algorithm and obtains a satisfactory skeleton. When combined with suitable parameters, improved performance from a handwriting classifier is achieved. The experimental results from over 13000 numerals show the efficiency and robustness of the proposed method, raising recognition rates by over 10% for broken handwritten digits, from 74.8% to 86.4%.

Wijesoma, W.S., Kodagoda, K.R.S. & Teoh, E.K. 1999, 'Un-coupled fuzzy controller for longitudinal and lateral control of a golf car-like AGV', IEEE Conference on Intelligent Transportation Systems, Proceedings, ITSC, pp. 142-147.
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The 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 AGVs and mobile robots. The primary focus is on the development of an intelligent control scheme, which is insensitive to parametric uncertainty, load and parameter fluctuations and most importantly amenable to real time implementation. We have reviewed promising control schemes for steering and speed control of mobile robots. In this paper, we present an effective uncoupled direct fuzzy PD/PI control scheme for a particular outdoor AGV, which is a converted electrically powered golf-car. The controller performance is assessed against the required performance criteria and another nonlinear technique, viz. the computed torque technique (CTT).

Kodagoda, S., Wijesoma, W.S. & Teoh, E.K. 2005, 'Robust Un-Coupled Fuzzy Controller for Longitudinal and Lateral Control of an AGV', Lecture Notes in Computer Science 1625, International Conference on Computational Intelligence, Theory and Applications, Springer, Germany, pp. 370-381.

Wijesoma, W.S. & Kodagoda, S. 1999, 'Synthesis of Stable Fuzzy PD/PID control laws for Robotic Manipulators from a Variable Structure Systems Standpoint', Lecture Notes in Computer Science 1625, International Conference on Computational Intelligence, Theory and Applications,, Springer, Germany, pp. 495-511.