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.
Fang, JQ, Li, QS & Liu, DK 1999, 'Non-spillover control design of tall buildings in modal space', Wind and Structures, vol. 2, no. 3, pp. 189-200.
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In this paper, a new algorithm for active control design of structures is proposed and investigated. The algorithm preserves the decoupling property of the modal vibration equation and eliminates the spillover problem, which is the main shortcoming in the independent modal space control (IMSC) algorithm. With linear quadratic regulator(LQR) control law, the analytical solution of algebraic Riccati equation and the optimal actuator control force are obtained, and the control design procedure is significantly simplified. A numerical example for the control design of a tall building subjected to wind loads demonstrates the effectiveness of the proposed algorithm in reducing the acceleration and displacement responses of tall buildings under wind actions.
Fang, JQ, Li, QS, Jeary, AP & Liu, DK 1999, 'Damping of tall buildings: its evaluation and probabilistic characteristics', The Structural Design of Tall Buildings, vol. 8, no. 2, pp. 145-153.
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Fang, JQ, Li, QS, Jeary, AP, Liu, DK & Wong, CK 1999, 'Probabilistic characteristics of damping in buildings', Wind and Structures, vol. 2, no. 2, pp. 127-131.
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This paper describes probabilistic characteristics of damping in a tall building based on the results of full-scale measurement. It is found, through statistical analysis of the damping data, that the probability density function(PDF) of damping at the high amplitude plateau can be well represented by Normal distribution (Gaussian distribution). A stochastic damping model is proposed to estimate amplitude-dependent damping for practical application.
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, Zheng, L, Yang, G-H & Zhang, S 1999, 'The decoupling of a class of large-scale systems with symmetric circulant structure', IFAC Proceedings Volumes, vol. 32, no. 2, pp. 5903-5908.
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Ji, JC & Chen, YS 1999, 'Bifurcation in a parametrically excited two-degree-of-freedom nonlinear oscillating system with 1 : 2 internal resonance', APPLIED MATHEMATICS AND MECHANICS-ENGLISH EDITION, vol. 20, no. 4, pp. 350-359.
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The nonlinear response of a two-degree-of-freedom nonlinear oscillating system to parametric excitation is examined for the care of 1 : 2 internal resonance and, principal parametric resonance with respect to the lower mode. The method of multiple scales is used to derive four first-order autonomous ordinary differential equations for the modulation of the amplitudes and phases. The steady-state solutions of the modulated equations and their stability are investigated. The trivial solutions lose their stability through pitchfork bifurcation giving rise to coupled made solutions. The Melnikov method is used to study the global bifurcation behavior, the critical parameter is determined at which the dynamical system possesses a Smale horseshoe type of chaos.
Ji, JC, Yu, L & Chen, YS 1999, 'Amplitude modulated motions in a two degree-of-freedom system with quadratic nonlinearities under parametric excitation: Experimental investigation', MECHANICS RESEARCH COMMUNICATIONS, vol. 26, no. 4, pp. 499-505.
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Ji, JC, Yu, L & Chen, YS 1999, 'Bifurcation and amplitude modulated motions in a parametrically excited two-degree-of-freedom non-linear system', JOURNAL OF SOUND AND VIBRATION, vol. 228, no. 5, pp. 1125-1144.
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The non-linear response of a T-shaped beam-mass structure is investigated theoretically and experimentally for the case of one-to-two internal resonance and principal parametric resonance of the lower mode. The method of multiple scales is used to determine four first order amplitude- and phase-modulation equations. The non-trivial steady state solutions are obtained from trivial solutions through pitchfork bifurcation. The Melnikov's method is used to predict the critical parameter at which the dynamical system possesses a Smale horseshoe type of chaos. To verify the analytical results, experiments were performed on the T-shaped beam-mass structure. The periodically amplitude-modulated motions and chaotically amplitude-modulated motions were observed during experiments. The results of the experiment showed good qualitative agreement with the theoretical predictions.
Li, Q, Cao, H, Li, G, Li, S & Liu, D 1999, 'Optimal design of wind-induced vibration control of tall buildings and high-rise structures', Wind and Structures, vol. 2, no. 1, pp. 69-83.
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The most common used control device on tall buildings and high-rise structures is active and passive tuned mass damper (ATMD and TMD). The major advantages of ATMD and TMD are discussed. The existing installations of various passive/active control devices on real structures are listed. A set of parameter optimization methods is proposed to determine optimal parameters of passive tuned mass dampers under wind excitation. Simplified formulas for determining the optimal parameters are proposed so that the design of a TMD can be carried out easily. Optimal design of wind-induced vibration control of frame structures is investigated. A thirty-story tall building is used as an example to demonstrate the procedure and to verify the efficiency of ATMD and TMD with the optimal parameters.
Li, QS, Fang, JQ & Liu, DK 1999, 'Evaluation of structural dynamic responses by stochastic finite element method', Structural Engineering and Mechanics, vol. 8, no. 5, pp. 477-490.
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Li, QS, Liu, DK & Fang, JQ 1999, 'Optimum Design of Actively Controlled Structures Using Genetic Algorithms', Advances in Structural Engineering, vol. 2, no. 2, pp. 109-118.
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Optimal placement of actuators in actively controlled structures is a mixed-discrete optimization problem; it has the characteristics of nonlinear, non-continuous, and so on. For this type of optimization problem, traditional optimization methods based on mathematical programming may not be effective. In this paper, the complexity, discreteness and non-linearity of the optimal design problems of actuator placement are investigated. An optimal control algorithm and active tendon controllers are applied to control the response of a 16-storey building under earthquake loads. A mathematical model of optimal actuator configuration is established. Based on the special optimization problem of actuator configuration in an actively controlled structure, a modified genetic algorithm is presented and applied to solve the problems. A design procedure/method is presented for this kind of optimization problem, and the suitability of this method for the optimization problem is investigated. The numerical calculation and analysis are carried out for the building controlled by active tendon control mechanisms, and the results are discussed and analyzed in detail.
Li, QS, Liu, DK, Fang, JQ, Jeary, AP & Wong, CK 1999, 'Using neural networks to model and predict amplitude dependent damping in buildings', Wind and Structures, vol. 2, no. 1, pp. 25-40.
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In this paper, artificial neural networks, a new kind of intelligent method, are employed to model and predict amplitude dependent damping in buildings based on our full-scale measurements of buildings. The modelling method and procedure using neural networks to model the damping are studied. Comparative analysis of different neural network models of damping, which includes multi-layer perception network (MLP), recurrent neural network, and general regression neural network (GRNN), is performed and discussed in detail. The performances of the models are evaluated and discussed by tests and predictions including self-test, `one-lag' prediction and `multi-lag' prediction of the damping values at high amplitude levels. The established models of damping are used to predict the damping in the following three ways: (1) the model is established by part of the data measured from one building and is used to predict the another part of damping values which are always difficult to obtain from field measurements: the values at the high amplitude level. (2) The model is established by the damping data measured from one building and is used to predict the variation curve of damping for another building. And (3) the model is established by the data measured from more than one buildings and is used to predict the variation curve of damping for another building. The prediction results are discussed.
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. 08, no. 03, 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, EM & 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
Shoudong Huang, Lam, J, Guang-Hong Yang & Siying Zhang 1999, 'Fault tolerant decentralized H/sub ∞/ control for symmetric composite systems', IEEE Transactions on Automatic Control, vol. 44, no. 11, pp. 2108-2114.
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Wei, D, Cheng, D, Wu, D & Bai, G 1999, 'Experimental study on deformation of sharpened stock corner in grooveless rolling', Kang T'ieh/Iron and Steel (Peking), vol. 34, no. 1, pp. 27-30.
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The sharp corner coefficient is defined to describe quantitatively the degree of sharpened corner of grooveless rolled stock. The deformation of the sharpened corner was studied. The stock corners tend to sharp unavoidably in grooveless rolling. The degree of sharpened corner is related with the draft ratio and the ratio of height to width of the pre-rolled stock. It is favorable to alleviate corners to sharpen extremely that adopting the rectangle/rectangle sequence in grooveless rolling.
Wijesoma, WS, Kodagoda, KRS & Teoh, EK 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).