Feedforward Control of Waves in Lattice Elements.

Abstract

The motion in a lattice substructural element, within which longitudinal stress waves propagate nondispersively and without attenuation, is assumed to be governed by the classical wave equation. A feedforward controller configuration is proposed to isolate a portion of the substructure from longitudinal wave disturbances. The governing equations for the propagation of incoming and controller-generated stress waves in the substructure are determined. To prevent instability, the controller must respond to incoming stress waves only, disregarding self-generated outgoing waves. The transfer function for the controlled substructure system is derived. The dependence of the transfer function magnitude on the input waveform frequency as well as on controller error parameters is demonstrated. The ranges of acceptable controller error are determined for the operational goals of disturbance cancellation and disturbance amplitude attenuation. Keywords: Wave propagation; Control; Lattice structures; Large space structures.

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Document Details

Document Type
Technical Report
Publication Date
Aug 01, 1985
Accession Number
ADA164009

Entities

People

  • Gregory A. Norris
  • James H. Williams Jr.
  • Samson S. Lee

Organizations

  • Massachusetts Institute of Technology

Tags

Communities of Interest

  • Sensors
  • Space

DTIC Thesaurus Topics

  • Actuators
  • Classification
  • Closed Loop Systems
  • Control Systems
  • Equations
  • Feedback
  • Frequency
  • Frequency Response
  • Large Space Structures
  • Linear Systems
  • Scientific Research
  • Stress Waves
  • Transfer Functions
  • Wave Equations
  • Wave Propagation
  • Waveforms
  • Waves

Readers

  • Atmospheric Science / Meteorology, specifically Wind Wave Turbulence.
  • Robotics and Automation.
  • Structural Health Monitoring of Composite Structures.

Technology Areas

  • Space
  • Space - Spacecraft Maneuvers