Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 5 of 5
Full-Text Articles in Engineering
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 …
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
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 …
Using Asterisms To Decode Multi-User Mimo Systems, Phillip Conder, Tadeusz A. Wysocki
Using Asterisms To Decode Multi-User Mimo Systems, Phillip Conder, Tadeusz A. Wysocki
Faculty of Engineering - Papers (Archive)
The area of Multiple Input Multiple Output (MIMO) communications systems has received enormous attention recently as they can provide a roughly linear increase in data rate by using multiple transmit and receive antennas. MIMO combined with an Turbo coding has been shown as a promising way to achieve near capacity for wireless channels. This paper proposes applying an Asterism based decoder to produce an additional multi user access scheme on top of the primary access method for Ad Hoc networks. After reviewing Sphere and Asterism decoding for MIMO systems with a larger number of transmit than receive antennas, this paper …
Analysis And Modelling Of Trust In Distributed Information Systems, Weiliang Zhao, Vijay Varadharajan, George Bryan
Analysis And Modelling Of Trust In Distributed Information Systems, Weiliang Zhao, Vijay Varadharajan, George Bryan
Faculty of Engineering - Papers (Archive)
In this paper, we consider the analysis and modelling of trust in distributed information systems.We review the relations of trust relationships in our previous work.We discuss trust layers and hierarchy based on formal definition of trust relationship.We provide a set of definitions to describe the properties of trust direction and trust symmetry under our taxonomy framework.In order to analyze and model the scope and diversity of trust relationship, we define trust scope label under our taxonomy framework.We provide some example scenarios to illustrate the proposed definitions about properties of trust relationship. The proposed definitions are new elements of the taxonomy …
Combined Asterism And Sphere Decoder For Large Asymmetric Mimo Systems, Phillip Conder, Tadeusz A. Wysocki
Combined Asterism And Sphere Decoder For Large Asymmetric Mimo Systems, Phillip Conder, Tadeusz A. Wysocki
Faculty of Engineering - Papers (Archive)
Multiple input multiple output (MIMO) communications systems have received enormous attention recently as they can provide a roughly linear increase in data rate by using multiple transmit and receive antennas. The optimal detection strategy for a MIMO receiver is to perform a maximum-likelihood (ML) search over all possible transmitted symbol combinations which has an exponential complexity when the constellation size of the number of transmit antennas increases. Sphere and asterism decoders are schemes that achieved ML performance for MIMO systems, but both have shortcomings in computational complexity, sphere decoding when nt>nr and asterism when nt r. …