Subject:
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Re: Motor Sensor (fwd)
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Newsgroups:
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lugnet.robotics
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Date:
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Wed, 9 Jun 1999 22:23:38 GMT
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Original-From:
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Shawn Menninga <smq@dwarfrune.STOPSPAMMERScom>
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Viewed:
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1359 times
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At 07:14 09-06-99 -0500, you wrote:
>
> ----- Forwarded message from Kekoa Proudfoot -----
>
> > It's actualy not velocity, it's angular accelleration.
>
> It's actually not angular acceleration, it's angular velocity.
>
> ----- End of forwarded message from Kekoa Proudfoot -----
>
> Can't be dude. Re-read your basic mechanics. For *any* object to go in a
> circle it's 'accelleration', otherwise there is no way to take into account
> the change in vector of the velocity vector which is always chaning
> (precessing in a circle). Last time I checked anytime a velocity vector
> changed that was an accelleration (dv/dt).
Exerpted from the appendix of my college physics book: :-)
Standard Representations for Newtonian Kinematic Quantities
1) Linear forms
Position (x) -- units from a fixed origin in one dimension
Velocity (v) -- time rate of change of linear position (dx/dt)
Acceleration (a) -- time rate of change of linear velocity (dv/dt)
2) Vector forms
Position (P = <x,y,z,...>) -- units from a fixed origin in two or more
dimensions
Velocity (V) -- time rate of change of vector position
(dP/dt = <dx/dt,dy/dt,dz/dt,...>)
Acceleration (A) -- time rate of change of vector velocity (dV/dt)
3) Angular forms
Position (theta) -- angular units (radians) from a fixed angular position
Velocity (omega) -- time rate of change of angular position (d theta/dt)
Acceleration (nu) -- time rate of change of angular velocity (d omega/dt)
So with a simple spinning wheel, you've got angular velocity and vector
acceleration. Case closed. :-)
Also, in case anyone's interested, yes, there is a fourth set dealing
with rotations about axes in multiple dimensions. Position is usually
given as a 3-tuple (theta, phi, psi) of angular positions. Velocity and
acceleration, hoverer, are considerably more complex mathematically than
the forms above. For anyone who really wants to know, I'd recommend
"Quaternions and Rotation Sequences: A Primer with Applications to Orbits,
Aerospace, and Virtual Reality; Jack B. Kuipers; Princeton University
Press; 1999" but beware that the math gets deep really quickly...
Now back to your regularly scheduled vacuum cleaners. :-)
-SMQ Shawn Menninga smq@dwarfrune.com
--=--=--=--=--=--=--=--=--=--=--=--=---=--=--=--=--=--=--=--=--=--=--=--=--
"Well I've wrestled with reality for thirty-five years now, doctor, and I'm
happy to state I've finally won out over it." -- Elwood P. Dowd, Harvey
--
Did you check the web site first?: http://www.crynwr.com/lego-robotics
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Message is in Reply To:
 | | Re: Motor Sensor (fwd)
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| ----- Forwarded message from Kekoa Proudfoot ----- Subject: Re: Motor Sensor (fwd) Date: Wed, 9 Jun 1999 01:56:23 GMT (...) It's actually not angular acceleration, it's angular velocity. ----- End of forwarded message from Kekoa Proudfoot ----- (...) (25 years ago, 9-Jun-99, to lugnet.robotics)
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