Re: MADEFAST Design, Trdeoffs, and Affordability

Ruzena Bajcsy <>
Message-id: <>
To: dwhitney@MIT.EDU (Dan Whitney)
        Bill Birmingham <>,
        Susan_Finger@WYVERN.CIMDS.RI.CMU.EDU,,,,,,, gruber@HPP.Stanford.EDU,
        "Glenn A. Kramer" <>,,,,,
        "Greg Twiss" <>,
        Kevin Lyons <>, Pradeep Khosla <>,
        "Peter F. Brown" <>, Mike McGrath <>,
Subject: Re: MADEFAST Design, Trdeoffs, and Affordability 
In-reply-to: Your message of "Mon, 07 Mar 1994 08:23:15."
Date: Mon, 07 Mar 1994 08:47:31 EST
From: Ruzena Bajcsy <>

 >>I'm glad to see the "design" part of the program starting to take some 
 >>shape.  I'd like to add some other considerations that may stretch the 
 >>group a little but are a basic part of realistic design and may get 
 >>ARPA's attention:
 >>The specifications for a seeker include pointing accuracy and bandwidth.  
 >>These together mean that it should be able to find and lock onto a 
 >>target and keep hold of it even if it moves rapidly.  It should also be 
 >>able to report the target's heading in two angle dimensions accurately, 
 >>both when the target is apparently stationary and when it is moving.  It 
 >>should also be able to do this when the target is dim and hard to 
I could not agree with you more!!!
 >>These requirements "flow down" to particular design parameters like 
 >>gimbal motor torque, servo gain and damping, gimbal stiffness and mass, 
 >>rate gyro sensitivity,  bearing runout, sensor sensitivity (hence size 
 >>and weight), and assembled tolerances (do the two gimbal axes intersect? 
 >>do they intersect at the center of the sensor, etc.)
 >>There is an overall diameter and weight limit as well.  These limits 
 >>make it hard to meet the requirements above.  A cost limit will be even 
 >>harder to meet.  
 >>Altogether this mixed set of requirements will require tradeoffs to be 
 >>made between cost and performance.  This is a basic trade which is 
 >>little practiced in DoD work, though it is the main driver in commercial 
 >>work.  Developing collaborative tools to do tradeoffs would be a big 
 >>contribution as DoD strives to define what "affordability" means.

All above what you said is so much true and offers beatifull design research
Right on,