FIELD AND SPACE ROBOTICS LABORATORY

DEPARTMENT OF MECHANICAL ENGINEERING

MASSACHUSETTS INSTITUTE OF TECHNOLOGY

HOME

FACILITIES

PEOPLE

PROJECTS

CURRENT PROJECTS

SPONSORS

PUBLICATIONS

RESEARCH OPPORTUNITIES

 

MIRROR PROJECT

Principal Investigator

Steven Dubowsky

Richard Wiesman

Group Members

Paul Lee, MS Student

LiFang Li, Visiting Student

Richard Heller, MS Student

Amy Bilton, PHD Student

Motivation

 The shape of reflective surfaces in space telescopes and solar concentrators determines their performance.  Manufacturing of these precision surfaces is difficult, and their performance can be degraded by disturbances such as wind or thermal warping.  Embedding simple binary actuators in the mirror structure has the potential to simplify manufacturing processes and increase system performance.

 Research Focus

 This work focuses in three main areas to make shape correction through binary actuators practical for implementation in solar concentrators and space telescopes: Structure design optimization, shape control, experimental concept evaluation.

 Structure Design Optimization

 Research is currently being conducted to optimize the design of the structures.  Analytical models are also currently being developed for a generalized structure with embedded binary actuators.  These models will be utilized to create precise arrangements with the minimum number of actuators.  Finite element models are also currently being developed to analyze the performance of the initial target applications.  A sample FEA model of the experimental setup can be seen in Figure 1.

 

Figure 1: FEA Model of Experimental Setup

 

Control

 Closed-loop control will be required to correct the mirror shape.  Although the control signal is simple, determining which actuators to deploy to correct the mirror shape is not trivial.  The system model will likely be imprecise due to uncertainties in the structural parameters.  Control algorithms that accommodate this model uncertainty are currently being developed.

 Experimental Evaluation

 In support of the above research areas, an experimental system has been built.  The system will be utilized to experimentally validate analytical models and finite element analysis.  This system uses 12 binary actuators to control the shape of the mirror surface.  The system can be seen in Figure 2 below.

 

Figure 2: Experimental System Setup

 


 

Sponsors

Northrop Grumman

 

Copyright 1995-2010 by MIT.

All rights reserved.