Engineering Commons^™

Structural Control Of D-F Interaction In The Cefe1−Xruxaso System System, Cao Wang, Hao Jiang, Yongkang Luo, Chunmu Feng, Wenxian Li, Zhu-An Xu, Guanghan Cao, Jung Ho Kim, S. X. Dou

Faculty of Engineering - Papers (Archive)

The isovalent substitution effect of Ru in CeFe1−xRuxAsO (0 ≤ x ≤ 1) has been systematically studied by powder X-ray diffraction, electrical resistivity, magnetization, and specific heat measurements. The antiferromagnetic (AFM) ordering of both d and 4f electrons are suppressed upon Ru doping, followed by Pauli paramagnetism (d electrons) and local moment paramagnetism (4f electrons) with strong ferromagnetic fluctuation, respectively. Neither superconductivity above 2K nor pronounced Kondo screening are observed in the substitution phase diagram. Combined with published results of the cerium-based quaternary compounds CeMXO(M =Fe, Ru; X =P, As), our data suggest that the end member CeRuAsO is on …

Use Of The Soil Modulus For Compaction Control Of Compacted Soils, Ana Heitor, Buddhima Indraratna, Cholachat Rujikiatkamjorn

Faculty of Engineering - Papers (Archive)

Insufficient compaction conditions can cause significant roadway infrastructure maintenance costs. Conventional compaction control, using nuclear methods, is based on the discrete in situ determination of the dry density and moisture content. Recently, there has been an increase interest in alternative methods for compaction control using intelligent compaction technologies. This method enables the continuous measurement of the soil modulus and the degree of compaction on the layer that is being compacted. Thus, the efficiency of the compaction process can be maximized. Although the adoption of this method is very promising, it constitutes a change of project specification for the contractors (i.e. …

A New Adaptive Fuzzy-Hybrid Control Strategy Of Semi-Active Suspension With Magneto-Rheological Damper, Pipit Wahyu Nugroho, H Du, W H. Li, G Alici

Faculty of Engineering - Papers (Archive)

This paper presents the design and analysis of a new adaptive fuzzy (AF) logic and hybrid (skyhook plus groundhook) control technique applied to a semi-active suspension system of a quarter car mode. The hybrid control is applied because of its very good performance in ride comfort and road handling. Meanwhile, Fuzzy adaptive system is suitable for analysis of stability with non-linear performances. The adaptive fuzzy algorithm is used to approximate the estimated mass of the variable damping in the Hybrid loop. This model is adopting a Takagi-Sugeno configuration with a back propagation learning method typically used in a neural network …

Mine Gas Drainage And Outburst Control In Australian Underground Coal Mines, Najdat I. Aziz, Dennis Black, Ting Ren

Faculty of Engineering - Papers (Archive)

Australia produces both black and brown coal and is the world's fourth largest producer of black coal, after China, USA and India. Australian underground coal mines operate under controlled safety codes. The establishment of the mine safety management system, including the 1994 outburst management plan, contributed to a significant improvement in mine safety leading to non-fatality in outburst related incidences since 1994. The management of outburst risk, as a part of the overall safety and health management system is described. Also discussed are the introduction of outburst threshold limit values and the desorption rate index which forms the basis for …

Review Of Gas Emission Prediction And Control Methods For Multi-Seam Mining In Chinese Coal Mines, Zhongwei Wang, Ting Ren, Lei Zhang

Faculty of Engineering - Papers (Archive)

In China, the practice of multi-seam mining with high gas emission rates is common, and many coal mines are suffering from major gas management issues. To deal with these problems, empirical formulas for gas emission prediction and gas control methods suitable for site-specific conditions are developed. Specifically, the statistical method and split–source-method are widely used for gas emission prediction. In addition to ventilation, various gas control methods, including cross-measure boreholes, directional long-holes, dedicated roadways and surface goaf wells are used for gas drainage. Techniques for integrated extraction of coal and coal seam gas have been developed in these coal mines, …

Development Of A Water-Mist Based Venturi System For Dust Control From Maingate Chocks And Bsl, Ting Ren, Graeme Cooper, Srinivasa Yarlagadda

Faculty of Engineering - Papers (Archive)

Advances in modern longwall (LW) technology have resulted in high production faces with more powerful chocks and shearers that can advance at faster rates. As longwall chocks (supports) advance, crushed roof coal and/or rock can fall from the top of the chock canopy into the face ventilation airflow. Dust survey showed that chock movement is a significant source of dust exposure for shearer operators, accounting for about 47% of total LW face dust make during the cutting cycle. 3D CFD models have been developed to understand the behaviour of longwall dust particles from various sources including maingate (MG) chocks and …

Dust Monitoring And Control Efficiency Measurement In Longwall Mining, Brian Plush, Ting Ren, Ken Cram, Najdat I. Aziz

Faculty of Engineering - Papers (Archive)

Occupational hygiene has been an integral part of the mining industry for centuries; however its importance has grown with developments in mechanisation. While the focus in the past has quite correctly been on improving the controls on dust exposure, the future lies in identifying the efficiency of installed controls on operating longwalls, evaluating them through robust and quantitative sampling methods to ensure the most effective controls are in place to prevent occupational disease from occurring. The current statutory testing regime identifies the exposure levels of personnel on an operating face, which gives a snapshot of the dust that these persons …

Implementation And Application Of A Real-Time Control System Using Matlab/Xpc, Xiaofeng He, Zhengyi Jiang, Christopher David Cook, Yinshui Liu

Faculty of Engineering - Papers (Archive)

A real-time control system for rolling mill control such as the Hille 100 experimental rolling mill was developed based on Matlab Simulink, Real-Time Workshop and xPC Target. The Host-Target PCs architecture for the control system was introduced, then the approach for the implementation of data acquisition, real-time control and the associated graphic user interface (GUI), were discussed in detail. Some limitations of the commercial software were also presented. The developed control system has been verified with Hille 100 rolling mill in laboratory, indicating the effective application in rolling mill control.

Inversion-Based Feedforward Control Of Polypyrrole Trilayer Bender Actuators, Stephen W. John, Gursel Alici, Christopher David Cook

Faculty of Engineering - Papers (Archive)

Conducting polymer bending actuators show potential for unique manipulation devices, particularly at the microscale, given low actuation voltages, controllable manufacture, biocompatibility, and ability to operate in either air or liquid environments; however, the impracticalities of implementing feedback in these environments and at these scales can impede positional control of the actuator. This paper presents an application of inversion-based feedforward positional control to a trilayer bender actuator, which is shown to improve the performance without the use of feedback or adjustments to the chemistry of the device. The step and dynamic displacement responses have all been improved under the feedforward control …

The Comparison Between Nanostructure Control And Other Modifications To Improve The Electrochemical Performance Of Sno, Yong-Mook Kang, Min-Sik Park, Hua-Kun Liu, S. X. Dou

Faculty of Engineering - Papers (Archive)

With an advent of the ubiquitous era, the demand for rechargeable batteries with a higher energy density is getting more and more critical. It is because applications are emerging such as electric vehicles and various types of portable electronic devices. Carbonaceous materials are commonly adopted as the anode material for commercial lithium-ion secondary batteries because it can reversibly intercalate or de-intercalate Li ion. However, low capacity of carbon has become a limiting factor in wider applications, and high capacity alternative to carbonaceous material has thus been sought for. Even if tin and silicon have been considered as one of the …

Q-Learning Algorithm For Navigation Control Of Autonomous Blimp, Yiwei Liu, Zengxi Pan, David A. Stirling, Fazel Naghdy

Faculty of Engineering - Papers (Archive)

In this research, an autonomous control system for blimp navigation was developed using reinforcement learning algorithm. The aim of this research is to provide a blimp the capability to approach a goal position autonomously in an environment, where the dynamical models of the blimp and the environment are unknown. Webots™ Robotics Simulator (WRS) was used to simulate and evaluate the control strategy obtained through a one-step Q-learning method. The simulation data generated via WRS were then processed and analysed within MATLAB. The simulation results showed that the control policy acquired from Q-learning is much more effective compared to the traditional …

Control Of Autonomous Airship, Yiwei Liu, Zengxi Pan, David A. Stirling, Fazel Naghdy

Faculty of Engineering - Papers (Archive)

Scientific research and development on the control of autonomous airship have shown a significant growth in recent years. New applications appear in the areas such as freight carrier, advertising, monitoring, surveillance, transportation, military and scientific research. The control of Autonomous airship is a very important problem for the aerial robots research. In this paper, the previous research on the control of autonomous blimp is reviewed, Several popular control methods are categorized and discussed in detail. Then an intelligent navigation control method, reinforcement learning control, is introduced in the autonomous blimp which was used for 2007 UAV Outback Challenge. The future …

Process Control And Automation Developments In Welding, J Norrish

Faculty of Engineering - Papers (Archive)

With an international shortage of skilled welders and concerns about exposure of personnel to welding hazards it is appropriate to consider how joining processes can be simplified and automated. The paper reviews the process control techniques which have been applied to enhance the productivity and quality of welded joints. It seeks to explain the influence of power source design and computer control on these developments. In particular it will address the real time control of short arc GMAW and explain how by modulation of the transient electrical properties and high speed wire feed oscillation process performance has enhanced in several …

Online Performance Evaluation Of Alternative Control Strategies For Building Cooling Water Systems Prior To In-Situ Implementation, Zhenjun Ma, Shengwei Wang, Fu Xiao

Faculty of Engineering - Papers (Archive)

This paper presents the online test and evaluation of the performance of five practical control strategies (fixed set-point control method, fixed approach control method, two near optimal strategies and one optimal strategy) for building cooling water systems to identify the best strategy for future field validation. All of these strategies were tested and evaluated in a simulated virtual environment similar to the situation when they are actually implemented in practice. A virtual building system representing the real building and its central chilling system was developed and used to test the operational performance of the system controlled by different strategies. The …

Towards The Position Control Of Conducting Polymer Trilayer Bending Actuators With Integrated Feedback Sensor, Stephen John, Gursel Alici, Christopher D. Cook

Faculty of Engineering - Papers (Archive)

Conducting polymers have a wide range of reversibly controllable properties, leading to a number of potentially useful devices for robotic applications, including actuators, sensors and batteries. Conducting polymers have the advantages of low weight, low cost, flexibility, small activation potentials (

Motion Segmentation For Humanoid Control Planning, Matthew Field, David A. Stirling, Fazel Naghdy, Zengxi Pan

Faculty of Engineering - Papers (Archive)

The discovery of major management behaviours from human motion data and uncovering their underlying components is investigated. A range of methods for segmenting major shifts in multidimensional time series are compared in inducing plausible behaviours from motion data. These behaviours are considered as supersets of motion primitives that define a repertoire of manoeuvres available to the human. The resulting multilayered symbolic model is used as a framework for humanoid imitation and control. It is hoped that with appropriate matching and scaling of degrees of freedom, models can be tested by extracting a trajectory for a simulation of the Nao soccer …

Online Optimal Control Of The Central Chilling System In A Super High-Rise Commercial Building, Shengwei Wang, Zhenjun Ma

Faculty of Engineering - Papers (Archive)

This paper presents the online optimal control strategies of the central chilling system in a super high-rise building in Hong Kong. The work presented aims at developing a package of optimal control strategies and evaluating their energy saving potentials and finally implementing these strategies in the building to enhance its energy efficiency. Based on testing the effects of interactions within the cooling water system and chilled water system on the system operation performance, the optimal control strategies for the cooling water system and variable speed pumps with different installations in the secondary chilled water system are developed. These strategies are …

Robust Adaptive Control Of Conjugated Polymer Actuators, Yang Fang, Xiaobo Tan, Gursel Alici

Faculty of Engineering - Papers (Archive)

Conjugated polymers are promising actuation materials for bio- and micromanipulation systems, biomimetic robots, and biomedical devices. Sophisticated electrochemomechanical dynamics in these materials, however, poses significant challenges in ensuring their consistent, robust performance in applications. In this paper, an effective adaptive control strategy is proposed for conjugated polymer actuators. A self-tuning regulator is designed based on a simple actuator model, which is obtained through reduction of an infinite-dimensional physical model and captures the essential actuation dynamics. The control scheme is made robust against unmodeled dynamics and measurement noises with parameter projection, which forces the parameter estimates to stay within physically meaningful …

Ambient Intelligence Through Wireless Ad-Hoc Control Networks, Antoine Desmet, Fazel Naghdy, Montserrat Ros

Faculty of Engineering - Papers (Archive)

The potential of Wireless Ad-hoc Control Networks (WACNets) in realising ambient intelligence in a home environment is explored in this paper. The main objective is to achieve energy and resource efficiency while maintaining optimal comfort. WACNets is a novel concept developed by the Centre for Intelligent Mechatronics Research at the University of Wollongong for the purpose of providing a framework for highly distributed, intelligent wireless control networks. A WACNet consists of intelligent nodes developed on the IEEE 1451 Smart Sensor and ZigBee standards. The WACNet platform is fully selforganizing and employs a mesh of star-topology clusters. The development of an …

Motion Tracking Control Of Piezo-Driven Flexure-Based Mechanism Based On Sliding Mode Strategy, Hwee Choo Liaw, Bijan Shirinzadeh, Julian Smith, Gursel Alici

Faculty of Engineering - Papers (Archive)

This paper presents a motion tracking control methodology based on sliding mode strategy for a flexure-based micro/nano manipulator driven by a piezoelectric actuator. This control methodology is proposed for tracking of desired motion trajectories in the presence of uncertain system parameters, non-linearities including the hysteresis effect, and external disturbances in the control system. In this paper, a four-bar link is investigated and a lumped parameter dynamic model is established for the formulation of the proposed sliding mode motion control methodology. The convergence of the position tracking error to zero is assured by the approach in the presence of the aforementioned …

Robust Adaptive Control Of Conjugated Polymer Actuators, Yang Fang, Xiaobo Tan, Gursel Alici

Faculty of Engineering - Papers (Archive)

Conjugated polymers are promising actuation materials for bio and micromanipulation systems, biomimeticrobots, and biomedical devices. Sophisticated electrochemomechanical dynamics in these materials, however,poses significant challenges in ensuring their consistent, robust performance in applications. In this paper aneffective adaptive control strategy is proposed for conjugated polymer actuators. A self-tuning regulator isdesigned based on a simple actuator model, which is obtained through reduction of an infinite-dimensionalphysical model and captures the essential actuation dynamics. The control scheme is made robust againstunmodeled dynamics and measurement noises with parameter projection, which forces the parameter estimates tostay within physically-meaningful regions. The robust adaptive control method is applied …

The Simulation Of Magnetorheological Elastomers Adaptive Tuned Dynamic Vibration Absorber For Automobile Engine Vibration Control, X.C Zhang, X.Z. Zhang, W.H. Li, B. Liu, X.L. Gong, P.Q Zhang

Faculty of Engineering - Papers (Archive)

The aim of this article is to investigate the use of a Dynamic Vibration Absorber to control vibration of engine by using simulation. Traditional means of vibration control have involved the use of passive and more recently, active methods. This study is different in that it involves an adaptive component in the design of vibration absorber using magnetorheological elastomers (MREs) as the adaptive spring.

MREs are kind of novel smart material whose shear modulus can be controlled by applied magnetic field. In this paper, the vibration mode of a simple model of automobile engine is simulated by Finite Element Method …

Robust Motion Tracking Control Of Piezoelectric Actuation Systems, Hwee Choo Liaw, Denny Oetomo, Bijan Shirinzadeh, Gursel Alici

Faculty of Engineering - Papers (Archive)

This paper proposes a robust control methodology for piezoelectric actuation systems to track specified motion trajectories. This is motivated by the search for an effective control strategy to deal with the problem of nonlinear behaviour in the piezoelectric actuation systems. The basic concept associated with this approach lies in the specification of a target performance and the formulation of a robust control scheme for the system to ensure the convergence of the position tracking error to zero in the presence of parametric uncertainties and hysteresis effect inclusive of other un-modelled disturbances. Stability of the control system is proven theoretically and …

Characterisation And Control Of A Prototype Hts Smes Device, Christopher J. Hawley, Dominic Cuiuri, Christopher D. Cook, Steve Gower, Timothy Beales

Faculty of Engineering - Papers (Archive)

A 2.79 kJ prototype high transition temperature Superconducting Magnetic Energy Storage (SMES) device has been constructed. The coil for the prototype has been wound using High Temperature Superconducting (HTS) BSCCO-2223 tape. The refrigeration system is a gaseous helium cold head cryocooler used to maintain the SMES coil at a temperature of 30 K, improving the Ic characteristic of the coil by a factor of 4.7 compared to that at 77 K. The SMES device is capable of supplying a 3-phase load during power interruptions, and has been constructed during a program to develop a larger 20 kJ system aimed at …

Experimental Evaluation Of Adaptive And Variable Structure Control Of Piezoelectric Actuation Systems For Micro/Nano Manipulation, Hwee Choo Liaw, Bijan Shirinzadeh, Denny Oetomo, Gursel Alici

Faculty of Engineering - Papers (Archive)

This paper proposes and evaluates an adaptive technique and a variable structure control approach for piezoelectric actuation systems to track specified motion trajectories. The proposed control methodologies are formulated to accommodate unknown or uncertain system parameters, nonlinearities including the hysteresis effect, and external disturbances in the piezoelectric actuation systems without any form of feed-forward compensation. In this study, both control methodologies are demonstrated to possess a promising motion tracking ability experimentally. In comparison, the variable structure control approach is evaluated to be superior to the adaptive technique in the motion tracking control. With the ability to track motion trajectories under …

Special Class Of Positive Definite Functions For Formulating Adaptive Micro/Nano Manipulator Control, Hwee Choo Liaw, Denny Oetomo, Gursel Alici, Bijan Shirinzadeh

Faculty of Engineering - Papers (Archive)

This paper presents a special class of positive definite functions for the formulation of adaptive control strategies, specifically in the research of an effective control algorithm for piezoelectric actuation systems in micro/nano manipulation. To deal with the control problems of unknown system parameters, nonlinear hysteresis effects, and disturbances in the piezoelectric actuation systems, an adaptive control methodology is proposed. Using the saturation function derived from a positive definite function to formulate the control methodology, the closed-loop system stability can be guaranteed. Furthermore, the control methodology is proposed to track a desired motion trajectory in position, velocity, and acceleration. In this …

Physical Layer Of Wireless Ad-Hoc Control Networks, Shengrong Bu, Fazel Naghdy, Philip Ciufo

Faculty of Engineering - Papers (Archive)

A new concept called Wireless ad-hoc control networks (WACNets), designed for distributed and remote monitoring and control is explored in this work. It is suggested that ad-hoc control networks are the next stage in the development of distributed control and monitoring. WACNet explores a framework for organic, evolutionary and scalable method of integrating a large number of nodes with sensing and/or actuation, local intelligence and control, data processing and communication capabilities. A combination of IEEE 1451 compliant Smart Sensor and Bluetooth standard is employed to develop the first generation test-bed for the study of WACNets. The concept is introduced and …

Evaluation Of Control Techniques For Dip Transfer Gas Metal Arc Welding, Gary Dean, John Norrish, Christopher D. Cook

Faculty of Engineering - Papers (Archive)

Dip transfer gas metal arc welding (GMAW) is used extensively for high productivity welding of thin sheet steel, and is also useful for positional welding of thicker section steels. Unfortunately in the past, the process has gained a reputation for fusion defects, which becomes more apparent when welding traditionally difficult materials such as coated steels. This reputation can be attributed in some instances to the method of control used and the changeable nature of variables crucial to controlling heat transfer during the welding process. The paper examines the relationship between weld fusion, heat input and current for coated steel welding …

Model-Based Adaptive Control Of Piezoelectric Actuation Systems, Hwee Choo Liaw, Denny Oetomo, Bijan Shirinzadeh, Gursel Alici

Faculty of Engineering - Papers (Archive)

This paper proposes a model-based adaptive control methodology for piezoelectric actuation systems to follow specified motion trajectories. This is motivated by a search for an effective control strategy to deal with the problem of parametric uncertainties such as disturbance and hysteresis effects. The proposed adaptive law is formulated by combining a parameter compensator and a conventional PD feedback control for a system to drive its position tracking error converging to zero. The fundamental concept lies in the properties of a quasinatural potential function, which allows a saturated position error function in the control formulation. Implementation of the control law requires …

Robust Control Framework For Piezoelectric Actuation Systems In Micro/Nano Manipulation, Hwee Choo Liaw, Denny Oetomo, Bijan Shirinzadeh, Gursel Alici

Faculty of Engineering - Papers (Archive)

Micro/nano manipulation has been identified as one of the key enabling technologies for many emerging challenges. Within this scope, piezoelectric actuators have played major roles in achieving the required nano-resolution motion. This paper proposes a robust control framework for piezoelectric actuation systems to follow specified motion trajectories. The basic concept associated with this methodology lies in the specification of a target performance and the robust control scheme formulation for piezoelectric actuation systems to ensure the convergence of the position tracking error to zero. This control methodology is attractive as its implementation requires only the knowledge of the estimated system parameters …