Algorithms for on-line parameter and mode shape estimation

Algorithms are presented for on-line parameter and mode-shape estimation. The approach used is based upon a modal decomposition of the dynamic response of the flexible structure and is designed to make use of the parallel processing features of modern minicomputers. Satisfactory performance of the parallel structure identification technique used can be achieved only when the approximation functions noted correspond to the natural modes of the flexible structure. The work summarized here presents a technique for estimating both mode shapes and modal parameters

A Nonlinear Dual-Adaptive Control Strategy for Identification and Control of Flexible Structures

A technique is presented for obtaining a control law to regulate the modal dynamics and identify the modal parameters of a flexible structure. The method is based on using a min-max performance index to derive a control law which may be considered to be a best compromise between optimum one step control and identification inputs. Features of the approach are demonstrated by a computer simulation of the controlled modal response of a flexible beam

Design of a three-axis attitude control system for a spacecraft acted upon by random perturbations Final report

Three axis attitude control system for spacecraft under random perturbation

An adaptive learning control system for large flexible structures

The objective of the research has been to study the design of adaptive/learning control systems for the control of large flexible structures. In the first activity an adaptive/learning control methodology for flexible space structures was investigated. The approach was based on using a modal model of the flexible structure dynamics and an output-error identification scheme to identify modal parameters. In the second activity, a least-squares identification scheme was proposed for estimating both modal parameters and modal-to-actuator and modal-to-sensor shape functions. The technique was applied to experimental data obtained from the NASA Langley beam experiment. In the third activity, a separable nonlinear least-squares approach was developed for estimating the number of excited modes, shape functions, modal parameters, and modal amplitude and velocity time functions for a flexible structure. In the final research activity, a dual-adaptive control strategy was developed for regulating the modal dynamics and identifying modal parameters of a flexible structure. A min-max approach was used for finding an input to provide modal parameter identification while not exceeding reasonable bounds on modal displacement

Stability of attitude control systems acted upon by random perturbations

Mathematical models on stability of attitude control systems acted upon by random perturbation processe

Additional studies of quasi-optimum feedback control techniques

Quasi-optimal control technique for space vehicle attitude, bounded acceleration rendezvous in free space, and aircraft landing proble

TROPIC: Transactional Resource Orchestration Platform In The Cloud

Realizing Infrastructure-as-a-Service (IaaS) cloud requires a control platform to orchestrate cloud resource provisioning, configuration, and decommissioning across a distributed set of diverse physical resources. This orchestration is challenging due to the rapid growth of data centers, high failure rate of commodity hardware and the increasing sophistication of cloud services. This paper presents the design and implementation of TROPIC, a highly available, transactional resource orchestration platform for building IaaS cloud infrastructures. TROPIC’s orchestration procedures that manipulate physical resources are transactional, automatically guaranteeing atomicity, consistency, isolation and durability of cloud operations. Through extensive evaluation of our prototype implementation, we demonstrate that TROPIC can meet production-scale cloud orchestration demands, while maintaining our design goals of safety, robustness, concurrency and high availability

An Evaluation Model For Web-based 3D Mass Customization Toolkit Design

The development of geometric modelling technologies and web technologies provides the ability to present a virtual 3D product in a mass customization (MC) toolkit. Compared with 2D graphic toolkits, 3D toolkit design requires better consideration of individual customer needs, consumer and toolkit interaction, and also a means of integrating with the underlying technical infrastructure. However, there is currently no widely accepted model or criteria to regulate and evaluate 3D MC toolkit design. Given these considerations, in this paper we provide an evaluation model for web-based 3D toolkits and a heuristic evaluation of two representative commercial web-based 3D toolkits. The evaluation results indicate the usefulness and effectiveness of the model as a scale for evaluating 3D toolkits. It also reveals that despite a fair amount of effort that has been devoted to theoretical research, current 3D toolkits are still at an early development stage. We therefore conclude this paper by identifying and encouraging further topics and questions as directions for future research

What the disjunctivist is right about

There is a traditional conception of sensory experience on which the experiences one has looking at, say, a cat could be had by someone merely hallucinating a cat. Disjunctivists take issue with this conception on the grounds that it does not enable us to understand how perceptual knowledge is possible. In particular, they think, it does not explain how it can be that experiences gained in perception enable us to be in ‘cognitive contact’ with objects and facts. I develop this chal- lenge to the traditional conception and then show that it is possible to accommo- date an adequate account of cognitive contact in keeping with the traditional conception. One upshot of the discussion is that experiences do not bear the explanatory burden placed upon them by disjunctivists