Spacecraft simulators are widely used to study the dynamics, guidance, navigation, and control of a spacecraft on the ground. A spacecraft simulator can have three rotational degrees of freedom by using a spherical air-bearing to simulate a frictionless and microgravity space environment. The moment of inertia and center of mass are essential for control system design of ground-based three-axis...

The mechanical behavior of a supersolid is studied in the framework of a fully explicit model derived from the Gross-Pitaevskii equation without assuming any defect or vacancy. A set of coupled nonlinear partial differential equations plus boundary conditions is derived. The conditions of mechanical equilibrium are studied under external constraints such as steady rotation and external stress. ...

We show that a supersolid phase, exhibiting simultaneously solid and superfluid behavior, properly describes the finite electron crystallites that form in two-dimensional quantum dots under high magnetic fields. These crystallites rotate already in their ground state and exhibit a nonclassical rotational inertia. They are precursors to a supersolid crystal in the lowest Landau level. We use exa...

The biomechanical properties of an animal's locomotor structures profoundly influence the relationship between neuromuscular inputs and body movements. In particular, passive stability properties are of interest as they may offer a non-neural mechanism for simplifying control of locomotion. Here, we hypothesized that a passive stability property of animal flight, flapping counter-torque (FCT), ...

We investigate the behavior of impurity fields immersed in a larger condensate field in various dimensions. We discuss the localization of a single impurity field within a condensate and note the effects of surface energy. We derive the functional form of the attractive condensate-mediated interaction between two impurities. Generalizing the analysis to N impurity fields, we show that within va...

This paper demonstrates that techniques in flexible body dynamics can yield surprising results when applied to rigid bodies. The discussion presents a technique for constructing rigid bodies from collections of masses and springs, and demonstrates that the simulation calculates many features of rigid body dynamics such as the behavior of the center of mass and the moments of inertia, free of ch...

The authors investigated the mechanical basis of length perception through dynamic touch using specially designed rods in which the various moments of mass distribution (mass, static moment, and rotational inertia) were varied independently. In a series of 4 experiments, exploration style and rod orientation were manipulated such that the relative salience of moments of mass distribution varied...

The author studies the minimax optimal control problem for an extensible beam equation that takes into account rotational inertia effects. A velocity term multiplied by bilinear and disturbance functions to construct a strategy is added. existence of pair, meaning perturbation, proved assuming some conditions on considered quadratic cost function. pairs are provided adjoint systems correspond p...