Fang, JQ, Li, QS, Liu, DK, Jeary, AP & Wong, CK 2000, 'Wind effects on a very tall building and wavelet analysis', Proceedings of the Institution of Civil Engineers - Structures and Buildings, vol. 140, no. 2, pp. 151-159.
View/Download from: Publisher's site
View description>>
This paper describes the results obtained from full-scale measurements of wind effects on a 70-storey building which has a height of approximately 370 m and is the second tallest structure in Hong Kong. The field data presented include the wind speed, wind direction and wind-induced response, which were measured at the top of this building during the passage of Typhoon Sally in 1996. Application of a wavelet transform to analyse the field data of wind velocity and wind-induced response is presented and discussed. The variation in the local energy content, not accounted for in Fourier spectral analysis, is noted. The comparison of the Fourier spectrum and wavelet scalogram is made.
Kim, J, Moon, S-W, Lee, S-H, Kim, S-H, Hwang, D-H, Lee, S-J & Ra, S-W 2000, 'Implementation of an Initial Alignment Algorithm for a Stapdown Inertial Navigation system', Journal of Institute of Control, Robotics and Systems, vol. 6, pp. 138-145.
Kodagoda, KRS, Wijesoma, WS & Teoh, EK 2000, 'Stable fuzzy state space controllers for an AGV', Neural Networks for Signal Processing - Proceedings of the IEEE Workshop, vol. 2, pp. 672-681.
View description>>
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 for real time implementation. In this paper, we present a stable uncoupled direct fuzzy PD/PI control scheme for an outdoor AGV, which is a converted electrically powered golf-car. The controller performance was assessed both through simulations and experimental results. It was established that the fuzzy logic controller (FLC) yielded good performance even under uncertain and variable parameters in the model, unlike the computed torque technique (CTT) or conventional PID control. And in terms of real-time implementation the availability of custom fuzzy chips and the reduced computational complexity of the fuzzy controller as against the CTT, makes the fuzzy controller, an ideal choice amongst the two schemes.
Li, QS, Fang, JQ & Liu, DK 2000, 'Exact Solutions for Free Vibration of Single-Degree-of-Freedom Systems with Nonperiodically Varying Parameters', Journal of Vibration and Control, vol. 6, no. 3, pp. 449-462.
View/Download from: Publisher's site
View description>>
An analysis of free vibration of single-degree-of-freedom (SDoF) systems with nonperiodically varying parameters, such as variable mass and stiffness, is presented and discussed in this paper The vari ations, relative to time, of mass and stiffness are expressed by the selection of suitable expressions such as power functions and exponential functions, and the general governing differential equation for free vi bration of SDoF systems with nonperiodically varying parameters is established. The exact solutions for free vibration of such time-varying systems are derived. The obtained solutions demonstrate that free vibra tion of several undamped systems with nonperiodically varying parameters cannot be induced by an initial disturbance.
Li, QS, Fang, JQ, Jeary, AP, Wong, CK & Liu, DK 2000, 'Evaluation of wind effects on a supertall building based on full-scale measurements', Earthquake Engineering & Structural Dynamics, vol. 29, no. 12, pp. 1845-1862.
View/Download from: Publisher's site
Li, QS, Li, GQ & Liu, DK 2000, 'Exact solutions for longitudinal vibration of rods coupled by translational springs', International Journal of Mechanical Sciences, vol. 42, no. 6, pp. 1135-1152.
View/Download from: Publisher's site
Li, QS, Liu, DK, Fang, JQ & Tam, CM 2000, 'Multi-level optimal design of buildings with active control under winds using genetic algorithms', Journal of Wind Engineering and Industrial Aerodynamics, vol. 86, no. 1, pp. 65-86.
View/Download from: Publisher's site
Li, QS, Liu, DK, Fang, JQ, Jeary, AP & Wong, CK 2000, 'Damping in buildings: its neural network model and AR model', Engineering Structures, vol. 22, no. 9, pp. 1216-1223.
View/Download from: Publisher's site
Li, QS, Liu, DK, Leung, AYT, Zhang, N, Tam, CM & Yang, LF 2000, 'Modelling of structural response and optimization of structural control system using neural network and genetic algorithm', The Structural Design of Tall Buildings, vol. 9, no. 4, pp. 279-293.
View/Download from: Publisher's site
Li, QS, Liu, DK, Leung, AYT, Zhang, N, Tam, CM & Yang, LF 2000, 'Modelling of structural response and optimization of structural control system using neural network and genetic algorithm', Structural Design of Tall Buildings, vol. 9, no. 4, pp. 279-293.
View/Download from: Publisher's site
View description>>
This paper proposes an integrated approach to the modelling and optimization of structural control systems in tall buildings. In this approach, an artificial neural network is applied to model the structural dynamic responses of tall buildings subjected to strong earthquakes, and a genetic algorithm is used to optimize the design problem of structural control systems, which constitutes a mixed-discrete, nonlinear and multi-modal optimization problem. The neural network model of the structural dynamic response analysis is included in the genetic algorithm and is used as a module of the structural analysis to estimate the dynamic responses of tall buildings. A numerical example is presented in which the general regression neural network is used to model the structural response analysis. The modelling method, procedure and the numerical results are discussed. Two Los Angeles earthquake records are adopted as earthquake excitations.
Waldron, KJ & Hubert, CJ 2000, 'Control of contact forces in wheeled and legged off-road vehicles', EXPERIMENTAL ROBOTICS VI, vol. 250, pp. 205-214.
View description>>
The use of variable configuration vehicles creates the possibility of direct control of the contact forces between the foot or wheel of a vehicle and the ground. That control is an important element of the coordination of practical walking machines. Cont
Dissanayake, G, Durrant-Whyte, H & Bailey, T 1970, 'Computationally efficient solution to the simultaneous localisation and map building (SLAM) problem', Proceedings - IEEE International Conference on Robotics and Automation, pp. 1009-1014.
View description>>
The theoretical basis of the solution to the simultaneous localisation and map building (SLAM) problem where an autonomous vehicle starts in an unknown location in an unknown environment and then incrementally build a map of landmarks present in this environment while simultaneously using this map to compute absolute vehicle location is now well understood. Although a number of SLAM implementations have appeared in the recent literature, the need to maintain the knowledge of the relative relationships between all the landmark location estimates contained in the map makes SLAM computationally intractable in implementations containing more than few tens of landmarks. In this paper, the theoretical basis and a practical implementation of a computationally efficient solution to SLAM is presented. The paper shows that it is indeed possible to remove a large percentage of the landmarks from the map without making the map building process statistically inconsistent. Furthermore, it is shown that the efficiency of the SLAM can be maintained by judicious selection of landmarks, to be preserved in the map, based on their information content.
Liu, D, Zhang, N, Jeyakumaran, JM & Villanueva, L 1970, 'Dynamics and Shift Control of Automatic Transmissions', Proc. of the Fifth International Conference on Motion and Vibration Control, International Conference on Motion and Vibration Control, UTS, Sydney, australia, pp. 597-602.
Liu, D, Zhang, N, Lu, F & Q, SL 1970, 'Optimal Number and Positions of Actuators in Actively Controlled Structures', Proc. of the 5th International Conference on Motion and Vibration Control, International Conference on Motion and Vibration Control, UTS, Sydney, Australia, pp. 347-352.
Mongan, P, Bankes, A, Keneally, R, Carmichael, M & Fontana, J 1970, 'Pyruvate improves hepatic energy and antioxidant status during hemorrhagic shock in swine', ANESTHESIOLOGY, LIPPINCOTT WILLIAMS & WILKINS, pp. U159-U159.
Wijesoma, WS & Kodagoda, KRS 1970, 'Design of stable fuzzy controllers for an AGV', Proceedings. 2000 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS 2000) (Cat. No.00CH37113), Proceedings. 2000 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS 2000), IEEE, Japan, pp. 1044-1049.
View/Download from: Publisher's site
View description>>
Fuzzy logic control is a relatively new technology and hence it needs rigorous comparative analyses with other well-established conventional control schemes. Further, fuzzy controller stability analysis is a major hindrance for its popularity among control engineers. This paper shows how stable fuzzy controllers may be synthesized for a typical AGV from the perspective of variable structure systems (VSS) theory. VSS or sliding model control (SMC) is an established robust non-linear control methodology. The AGV is characterized by highly non-linear, coupled and configuration dependent dynamics, with uncertainty in model parameters. Similarity in performance of the fuzzy controllers to the SMC controller is demonstrated through experimental results obtained for steer control of the AGV.
Williams, SB, Newman, P, Dissanayake, G & Durrant-Whyte, H 1970, 'Autonomous underwater simultaneous localisation and map building', Proceedings - IEEE International Conference on Robotics and Automation, pp. 1793-1798.
View description>>
In this paper we present results of the application of a Simultaneous Localisation and Map building (SLAM) algorithm to estimate the motion of a submersible vehicle. Scans obtained from an on-board sonar are processed to extract stable point features in the environment. These point features are then used to build up a map of the environment while simultaneously providing estimates of the vehicle location. Results are shown from deployment in a swimming pool at the University of Sydney as well as from field trials in a natural environment along Sydney's coast. This work represents the first instance of a deployable underwater implementation of the SLAM algorithm.