Control Surface Actuator

A device which actuates aircraft control surfaces is disclosed. The actuator is disposed entirely within the control surface structure. This allows the gap between the wing structural box and the control surface to be reduced. Reducing the size of the gap is especially desirable for wings with high aspect ratio, wherein the volume of the structural box is at a premium

Geometric control of bacterial surface accumulation

Controlling and suppressing bacterial accumulation at solid surfaces is essential for preventing biofilm formation and biofouling. Whereas various chemical surface treatments are known to reduce cell accumulation and attachment, the role of complex surface geometries remains less well understood. Here, we report experiments and simulations that explore the effects of locally varying boundary curvature on the scattering and accumulation dynamics of swimming Escherichia coli bacteria in quasi-two-dimensional microfluidic channels. Our experimental and numerical results show that a concave periodic boundary geometry can decrease the average cell concentration at the boundary by more than 50% relative to a flat surface.Comment: 10 pages, 5 figure

Configurational and system requirements for control of large space systems

Control of large space systems, modeling, and control difficulties are discussed. Ground based analysis of spaceflight data are presented to determine structural dynamics characteristics for the purpose of revising control laws, and to trim the surface contour. Systems identification for adaptive control and automatic surface control are also considered

Surface control system for the 15 meter hoop-column antenna

The 15-meter hoop-column antenna fabricated by the Harris Corporation under contract to the NASA Langley Research Center is described. The antenna is a deployable and restowable structure consisting of a central telescoping column, a 15-meter-diameter folding hoop, and a mesh reflector surface. The hoop is supported and positioned by 48 quartz cords attached to the column above the hoop, and by 24 graphite cords from the base of the antenna column. The RF reflective surface is a gold plated molybdenum wire mesh supported on a graphite cord truss structure which is attached between the hoop and the column. The surface contour is controlled by 96 graphite cords from the antenna base to the rear of the truss assembly. The antenna is actually a quadaperture reflector with each quadrant of the surface mesh shaped to produce an offset parabolic reflector. Results of near-field and structural tests are given. Controls structures and electromagnetics interaction, surface control system requirements, mesh control adjustment, surface control system actuator assembly, surface control system electronics, the system interface unit, and control stations are discussed

Nonlinear Control of Unmanned Surface Vehicle

An Unmmaned Surface Vehicle is a marine vehicle which has a complicated nonlinear model and partially uncertain parameters in its model. Therefore, an USV needs an advance control technique to solve this complicated problem. Nonlinear control is the most suitable technique to control this model. Nonlinear control is less sensitive to parameter uncertainty and disturbance perturbation which is beneficial for Unmanned Surface Vehicle which has highly disturbance parameter perturbation also. In the previous work, a disturbance model has never been considered in the control process due to highly perturbation in the model. Therefore, this work take account of the disturbance factors of Unmanned Surface Vehicle model