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Motion Segmentation For Humanoid Control Planning, Matthew Field, David A. Stirling, Fazel Naghdy, Zengxi Pan
Motion Segmentation For Humanoid Control Planning, Matthew Field, David A. Stirling, Fazel Naghdy, Zengxi Pan
Dr David Stirling
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 …
Control Of Autonomous Airship, Yiwei Liu, Zengxi Pan, David A. Stirling, Fazel Naghdy
Control Of Autonomous Airship, Yiwei Liu, Zengxi Pan, David A. Stirling, Fazel Naghdy
Dr David Stirling
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 …
Q-Learning Algorithm For Navigation Control Of Autonomous Blimp, Yiwei Liu, Zengxi Pan, David A. Stirling, Fazel Naghdy
Q-Learning Algorithm For Navigation Control Of Autonomous Blimp, Yiwei Liu, Zengxi Pan, David A. Stirling, Fazel Naghdy
Dr David Stirling
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 …
Ambient Intelligence Through Wireless Ad-Hoc Control Networks, Antoine Desmet, Fazel Naghdy, Montserrat Ros
Ambient Intelligence Through Wireless Ad-Hoc Control Networks, Antoine Desmet, Fazel Naghdy, Montserrat Ros
Dr Montserrat Ros
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 …
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
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
Gursel Alici
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 …
Towards The Position Control Of Conducting Polymer Trilayer Bending Actuators With Integrated Feedback Sensor, Stephen John, Gursel Alici, Christopher D. Cook
Towards The Position Control Of Conducting Polymer Trilayer Bending Actuators With Integrated Feedback Sensor, Stephen John, Gursel Alici, Christopher D. Cook
Gursel Alici
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 (
Robust Adaptive Control Of Conjugated Polymer Actuators, Yang Fang, Xiaobo Tan, Gursel Alici
Robust Adaptive Control Of Conjugated Polymer Actuators, Yang Fang, Xiaobo Tan, Gursel Alici
Gursel Alici
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 …
Robust Motion Tracking Control Of Piezoelectric Actuation Systems, Hwee Choo Liaw, Denny Oetomo, Bijan Shirinzadeh, Gursel Alici
Robust Motion Tracking Control Of Piezoelectric Actuation Systems, Hwee Choo Liaw, Denny Oetomo, Bijan Shirinzadeh, Gursel Alici
Gursel Alici
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 …
Motion Tracking Control Of Piezo-Driven Flexure-Based Mechanism Based On Sliding Mode Strategy, Hwee Choo Liaw, Bijan Shirinzadeh, Julian Smith, Gursel Alici
Motion Tracking Control Of Piezo-Driven Flexure-Based Mechanism Based On Sliding Mode Strategy, Hwee Choo Liaw, Bijan Shirinzadeh, Julian Smith, Gursel Alici
Gursel Alici
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 …
Model-Based Adaptive Control Of Piezoelectric Actuation Systems, Hwee Choo Liaw, Denny Oetomo, Bijan Shirinzadeh, Gursel Alici
Model-Based Adaptive Control Of Piezoelectric Actuation Systems, Hwee Choo Liaw, Denny Oetomo, Bijan Shirinzadeh, Gursel Alici
Gursel Alici
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 …
Special Class Of Positive Definite Functions For Formulating Adaptive Micro/Nano Manipulator Control, Hwee Choo Liaw, Denny Oetomo, Gursel Alici, Bijan Shirinzadeh
Special Class Of Positive Definite Functions For Formulating Adaptive Micro/Nano Manipulator Control, Hwee Choo Liaw, Denny Oetomo, Gursel Alici, Bijan Shirinzadeh
Gursel Alici
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 …
Robust Control Framework For Piezoelectric Actuation Systems In Micro/Nano Manipulation, Hwee Choo Liaw, Denny Oetomo, Bijan Shirinzadeh, Gursel Alici
Robust Control Framework For Piezoelectric Actuation Systems In Micro/Nano Manipulation, Hwee Choo Liaw, Denny Oetomo, Bijan Shirinzadeh, Gursel Alici
Gursel Alici
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 …
Evaluation Of Control Techniques For Dip Transfer Gas Metal Arc Welding, Gary Dean, John Norrish, Christopher D. Cook
Evaluation Of Control Techniques For Dip Transfer Gas Metal Arc Welding, Gary Dean, John Norrish, Christopher D. Cook
Christopher Cook
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 …
Characterisation And Control Of A Prototype Hts Smes Device, Christopher J. Hawley, Dominic Cuiuri, Christopher D. Cook, Steve Gower, Timothy Beales
Characterisation And Control Of A Prototype Hts Smes Device, Christopher J. Hawley, Dominic Cuiuri, Christopher D. Cook, Steve Gower, Timothy Beales
Christopher Cook
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 …
Computer Control Of Machines With Friction For Precise Motion, Simon Webb, Zheng Li, Christopher David Cook
Computer Control Of Machines With Friction For Precise Motion, Simon Webb, Zheng Li, Christopher David Cook
Christopher Cook
We study the problem of precise control of machines with static and Coulomb friction. An experimental X-Y testbed built for testing various control methods is described and initial experimental results are presented. A simple pole placement controller is designed for computer control of the X-Y testbed based on a generalised sampled-data hold. Robustness and stability of the controller are analysed. Simulation suggests that this controller is able to achieve precise position control even when parameters of both the dynamics of the machine and the characteristics of friction are unknown
Implementation And Application Of A Real-Time Control System Using Matlab/Xpc, Xiaofeng He, Zhengyi Jiang, Christopher David Cook, Yinshui Liu
Implementation And Application Of A Real-Time Control System Using Matlab/Xpc, Xiaofeng He, Zhengyi Jiang, Christopher David Cook, Yinshui Liu
Christopher Cook
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
Inversion-Based Feedforward Control Of Polypyrrole Trilayer Bender Actuators, Stephen W. John, Gursel Alici, Christopher David Cook
Christopher Cook
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 Dynamics Of Legged Locomotion: Models, Analyses, And Challenges, Philip Holmes, Robert J. Full, Daniel E. Koditschek, John Guckenheimer
The Dynamics Of Legged Locomotion: Models, Analyses, And Challenges, Philip Holmes, Robert J. Full, Daniel E. Koditschek, John Guckenheimer
Daniel E Koditschek
Cheetahs and beetles run, dolphins and salmon swim, and bees and birds fly with grace and economy surpassing our technology. Evolution has shaped the breathtaking abilities of animals, leaving us the challenge of reconstructing their targets of control and mechanisms of dexterity. In this review we explore a corner of this fascinating world. We describe mathematical models for legged animal locomotion, focusing on rapidly running insects and highlighting past achievements and challenges that remain. Newtonian body–limb dynamics are most naturally formulated as piecewise-holonomic rigid body mechanical systems, whose constraints change as legs touch down or lift off. Central pattern generators …
Thermophysical Properties Of Slags For Process Control, Brian J. Monaghan, Robert F Brooks
Thermophysical Properties Of Slags For Process Control, Brian J. Monaghan, Robert F Brooks
Brian Monaghan
Thermophysical properties have been shown to be important in a number of industrial processes. Unfortunately, for a number of properties there are scant data available and/or the data that are available are 'of dubious quality. In the Thermo-Physical Property Group at the National Physical Laboratory (NPL) the aim has been to develop measurement techniques capable of working in the difficult environments that are typical of industrial processes. This paper presents current developments at NPL in techniques to measure the thermal diffusivity of liquid slags using a laser flash and insights into the copper smelting process using interfacial tension techniques.
Learning Lessons In Resilient Traffic Management: A Cross-Domain Study Of Vessel Traffic Service (Vts) And Air Traffic Control (Atc), Gesa Praetorius, Fulko Van Westrenen, Deborah Mitchell, Erik Hollnagel
Learning Lessons In Resilient Traffic Management: A Cross-Domain Study Of Vessel Traffic Service (Vts) And Air Traffic Control (Atc), Gesa Praetorius, Fulko Van Westrenen, Deborah Mitchell, Erik Hollnagel
Gesa Praetorius
Although younger than the maritime domain, aviation has had a huge impact on the system design and development within shipping. Stakeholders often look towards aviation to make shipping, and the way that traffic is handled and organised, safer, more efficient and more effective. Although legally not the same, Vessel Traffic Service (VTS) is frequently compared to Air Traffic Control (ATC). In this article the area of traffic management within the maritime and aviation domains is addressed from a Resilience Engineering perspective. Focus is placed on the arrival part of a mission. The comparison is based on information collected during two …