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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
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 …
A New Qim-Based Image Watermarking Method And System, Wenming Lu, Wanqing Li, Reihaneh Safavi-Naini, Philip O. Ogunbona
A New Qim-Based Image Watermarking Method And System, Wenming Lu, Wanqing Li, Reihaneh Safavi-Naini, Philip O. Ogunbona
Faculty of Engineering - Papers (Archive)
Embedding capacity, distortion and resilience to attacks are three key indicators to the performance of any image watermarking systems. Study has shown that Quantization Index Modulation (QIM) can in general achieve higher embedding capacity than Spread Spectrum (SS) systems at the same level of distortion. However, QIM is more sensitive to simple attacks such as Additive White Gaussian Noise (AWGN), Uniform Distribution Noise (UDN), and JPEG compression. This paper proposed a system to decompose the host signal into the embedding signal that is designed to be resilient to attacks and the correction signal. QIM is applied on the embedding signal …
Synthesis And Characteristics Of A Semi-Interpenetrating Polymer Network Based On Chitosan/Polyaniline Under Different Ph Conditions, Geoffrey M. Spinks, Seon Jeong Kim, Sun I. Kim, In Young Kim, Su Ryon Shin
Synthesis And Characteristics Of A Semi-Interpenetrating Polymer Network Based On Chitosan/Polyaniline Under Different Ph Conditions, Geoffrey M. Spinks, Seon Jeong Kim, Sun I. Kim, In Young Kim, Su Ryon Shin
Faculty of Engineering - Papers (Archive)
The chitosan/polyaniline (PANi) semi-interpenetrating network polymers (semi-IPN)s were prepared under different pH conditions. Changes of structural properties were investigated using Fourier transform infrared (FT-IR) spectroscopy, Solid-state 13C NMR and wide angle X-ray diffraction (WAXD). The spectroscopic studies revealed that the PANi had converted to its pH-switched, emeraldine salt (ES) form when prepared from solutions of pH
Poly (3-Methylthiophene) Based Electrochemical Actuators, Binbin Xi, Van-Tan Truong, Philip G. Whitten, Jie Ding, Geoffrey M. Spinks, G G. Wallace
Poly (3-Methylthiophene) Based Electrochemical Actuators, Binbin Xi, Van-Tan Truong, Philip G. Whitten, Jie Ding, Geoffrey M. Spinks, G G. Wallace
Faculty of Engineering - Papers (Archive)
Polythiophene, one of the most extensively studied conducting polymers, was selected as an actuator material due to its chemical and electrochemical stability both in air and moisture. In this work, poly(3-methylthiophene) based actuators were constructed electrochemically with a tubular geometrical configuration. The actuation behaviour was investigated regarding to the actuation strain generated, the stress produced and work per cycle performed by poly(3-methylthiophene) actuators. The effect of potential sweep rate and different electrolytes (ionic liquid and organic solvent) on the actuation performance were also explored. Poly(3-methylthiophene) actuators show an increase in actuation strain with an increase in applied load.
Characterization Of Conducting-Polymer-Based Bimorph Vibration Sensors, Weihua Li, Geoffrey M. Spinks, Lianbin Zhao, Yanzhe Wu, Dezhi Zhou, G G. Wallace
Characterization Of Conducting-Polymer-Based Bimorph Vibration Sensors, Weihua Li, Geoffrey M. Spinks, Lianbin Zhao, Yanzhe Wu, Dezhi Zhou, G G. Wallace
Faculty of Engineering - Papers (Archive)
This paper presents theoretical and experimental investigation of mechanical-electrical properties of conducting polymers based bimorph sensors. A material parameter, hCP , is proposed to represent linear relationship between induction charge and the applied external deformation. Based on this assumption, a constitutive equation for bimorph sensors under steady-state external loadings are constructed and then solved. Mechanical-electrical properties of bimorph sensors are experimentally studied using both vibration-amplitude sweep mode and frequency sweep mode. The material parameter hCP , is identified by comparing theoretical analysis and experimental results. The applications of conducting polymers based bimorph sensors in smart structures are also …
High-Temperature Creep-Deformation Behavior Of The Ni-Based Superalloy M963, Hongtao Zhu, Cheng Lu, A K. Tieu, Lizi He, Q. Zheng, X. F. Sun, Z. Q. Hu, H. R. Guan
High-Temperature Creep-Deformation Behavior Of The Ni-Based Superalloy M963, Hongtao Zhu, Cheng Lu, A K. Tieu, Lizi He, Q. Zheng, X. F. Sun, Z. Q. Hu, H. R. Guan
Faculty of Engineering - Papers (Archive)
The high-temperature creep-deformation behavior of a Ni-based M963 superalloy has been investigated over a broad stress range of 80 to 600 MPa at high temperatures (800 °C to 975 °C). The detailed dislocation configurations at different creep stages are examined through transmission electron microscopy (TEM). The results show that the deformation mechanism is stress and temperature dependent and mainly consists of three dislocation-controlling mechanisms: stacking faults and dislocation-pair shearing, dislocation bowing and Orowan looping, and dislocation climb.