Study of double gimballed momentum wheels in the attitude and orbit control system of a geostationary communication satellite

The potentials of a double glmballed mcwientum wheel as an actuator for the attitude oontrol of a geostationary communication satellite are discussed with respect to the related systems. A justification of the IXaW is given and the characteristics defining the wheel system are determined. They can serve to be the input to a detailed design of an...

Experimental and system study of Reaction Wheels. Part II: System study on wheel state feedback

The increasing power of on-board processors allows more freedom in the design and operation of reaction wheel control systems. This report discusses several performance and implementation aspects of the operation of wheel systems which have their own internal feedback control system. A model following control concept is found to be superior. The...

The use of orbital angular momentum of light beams for optical data storage

We present a method to optically store multiple information in one location by having angular momentum imparted to the scanning beam by optical phase objects that make up the information areas on a surface. We show that the light beam thus perturbed carries an optical vortex, the rotation of which can be detected in the near-field focal region...

Angular momentum dynamics and the intrinsic drift of monopolar vortices on a rotating sphere

On the basis of the angular momentum equation for a fluid shell on a rotating planet, we analyze the intrinsic drift of a monopolar vortex in the shell. Central is the development of a general angular momentum equation for Eulerian fluid mechanics based on coordinate-free, general tensorial representations of the underlying fluid dynamics on the...

Spatial mode projection for side-wall angle measurements

Finding a fast and precise method to measure the side-wall angle of periodic (or non-periodic) structures is still a very challenging problem in lithographic applications. For this reason, over the years, many techniques have been proposed to circumvent this limitation, with the final goal to give the most precise geometrical description of...

Graphic analysis of the linear and angular momentum of a dynamically balanced 1-dof pantographic linkage

This article presents a graphical analysis method for the verification of the gravity force balance and shaking force and shaking moment balance of a 1-DoF pantographic linkage. First the joint velocities of the linkage are graphically found of which the procedure is well known. To obtain the linear and angular momentum graphically, the mass...

Clebsch-Gordan Coefficients: A Quantum Mechanical and Mathematical Perspective

In this work, Clebsch-Gordan coefficients are studied from both a quantum mechanical and a mathematical perspective. In quantum mechanics, Clebsch-Gordan coefficients arise when two quantum systems with a certain angular momentum are combined and the total angular momentum is to be found. We start by discussing the relevant postulates of quantum...

Recovery from sagittal-plane whole body angular momentum perturbations during walking

Healthy individuals highly regulate their whole body angular momentum (WBAM) during walking. Since WBAM regulation is essential in maintaining balance, a better understanding is required on how healthy individuals recover from WBAM perturbations. We therefore studied how healthy individuals recover WBAM in the sagittal plane. WBAM can be...

Sagittal-plane balance perturbations during very slow walking: Strategies for recovering linear and angular momentum

Spatiotemporal gait characteristics change during very slow walking, a relevant speed considering individuals with movement disorders or using assistive devices. However, we lack insights in how very slow walking affects human balance control. Therefore, we aimed to identify how healthy individuals use balance strategies while walking very...

Ultrafast Time Dynamics of Plasmonic Fractional Orbital Angular Momentum

The creation and manipulation of optical vortices, both in free space and in two-dimensional systems such as surface plasmon polaritons (SPPs), has attracted widespread attention in nano-optics due to their robust topological structure. Coupled with strong spatial confinement in the case of SPPs, these plasmonic vortices and their underlying...

Effect of perturbation timing on recovering whole-body angular momentum during very slow walking

Humans prioritize regulation of the whole-body angular momentum (WBAM) during walking. When perturbed, modulations of the moment arm of the ground reaction force (GRF) with respect to the centre of mass (CoM) assist in recovering WBAM. For sagittal-plane perturbations of the WBAM given at toe off right (TOR), horizontal GRF modulations and...

Assessing Angular Momentum, Kinetics, and Energetics of a Rigid Body Using a Single Inertial Measurement Unit

Angular momentum, kinetics, and energetics, including total mechanical energy and its rate of change in relation to power exchange, are important quantities when analyzing human motion in sports, physical labor, and rehabilitation. Inertial measurement units (IMU)-based motion capture (MOCAP) systems provide a portable solution for the...