Attitude control law design for spacecraft large angle maneuvers is investigated in this paper. The feedback linearization technique is applied to the design of a nonlinear tracking control law. The output function to be tracked is the quaternion attitude parameter. The designed control law turns out to be a combination of attitude and attitude rate tracking command. The attitude-only output fu...

......................................................................................................... 5 PREFACE ............................................................................................................ 6 LIST OF ORIGINAL PUBLICATIONS ................................................................ 8 INTRODUCTION ...............................................................

The goal of the present study is to develop a decentralized coordinated attitude control algorithm for satellite formation flying. To handle the nonlinearity of the dynamic system, the problems of absolute and relative attitude dynamics are formulated for the State-Dependent Riccati Equation (SDRE) technique. The SDRE technique is for the first time utilized as a nonlinear controller of the rel...

This paper describes a method for estimating the attitude of an underwater robot. The method employs a new concept of sine rotation vector and uses both an attitude heading and reference system (AHRS) and a Doppler velocity log (DVL) for the purpose of measurement. First, the acceleration and magnetic-field measurements are transformed into sine rotation vectors and combined. The combined sine ...

This study focuses on the development of a precise attitude control system for small satellites. In general, conventional methods used for attitude control in standard-sized satellites are not applicable to small satellites because of constraints of power consumption, space requirements, and mass. In addition, small satellites are more greatly affected than standard-sized satellites by attitude...

This paper explores consumers' commitment to and conviction about their beliefs in the form of attitude certainty. Based on a review of past research, we present a new framework for understanding attitude certainty and how consumers' attitude certainty is shaped by their resisting or yielding to persuasive messages, or even by their reflections on the evidence supporting their attitudes. We pro...

The dental profession has a high risk of hepatitis B virus (HBV) contamination and can play a crucial role in controlling HBV cross-contamination. In this cross-sectional study we used unique methods to assess Tehran dentists' knowledge, attitude and behaviour regarding HBV. Two simulated HBV-positive patients visited 300 general/specialist dentists in their offices and recorded dentists' willi...

The more accessible an attitude is, the stronger is its influence on information processing and behavior. Accessibility can be increased through attitude rehearsal, but it remains unknown whether attitude rehearsal also affects the accessibility of related attitudes. To investigate this hypothesis, participants in an experimental condition repeatedly expressed their attitudes towards exemplars ...

Television news has gained a new dimension in terms of ideological approaches as a result of such factors as globalization, cross monopolization, presence of international companies etc. and certain strategies have been developed at the production, presentation and distribution stages of news. In this study, television news about a process called “settlement process” was investigated. In this f...

The present research explored the mechanisms of judgmental and memory correction for communication influence. Participants described a target person to an addressee who either liked or disliked the target. Participants’ descriptions were more positive when the addressee liked the target than when the addressee disliked the target. Mediation analyses showed that the effect of the addressee’s att...