Subject:
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Re: Inertial guidance
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Newsgroups:
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lugnet.robotics
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Date:
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Sat, 12 Jan 2002 18:28:23 GMT
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Viewed:
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2846 times
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In lugnet.robotics, sjbaker1@airmail.net writes:
> Ian Warfield wrote:
> >
> > In lugnet.robotics, Pete Sevcik writes:
> > > Has anyone tried to do inertial guidance with the RCX ?
> >
> > Uh, how do you mean? Inertia pretty much guides itself, unless you want to
> > abolish Newton's First Law...?
>
> The term "inertial guidance" refers to a navigational technique that involves
> carefully measuring the rotational and translational accelleration of the
> vehicle, then integrating that to derive the velocity and integrating *that*
> to get the vehicles position.
>
> The big problem with inertial guidance is precision. If you make even a
> tiny error in measuring accelleration, that will add up over time to create
> a larger error in your velocity - which in turn adds up over time to make
> for huge positional errors.
>
> It's generally useful to use inertial navigation only when you can
> periodically reset the error by reference to some absolute positioning
> cue. It's not generally a good idea to use inertial guidance on systems
> that can be the victims of impact forces - since those induce very large
> accellerations for very short amounts of time - those are almost impossible
> to measure with enough precision. Hence, the technique is mostly used on
> aircraft, missiles and spacecraft (where you don't expect to hit anything!)
>
> You also generally need six sensors in order to measure the accellerations
> in all six degrees of freedom - that's not gonna be nice for an RCX!
Ah, I see. Thanks for your explanation.
How would one make inertial sensors for the RCX anyway? I suppose you could
rig a plumb bob to a rotation sensor - but as you had already pointed out,
rotation sensors are inaccurate at low rotation speeds. Hmm...
--Ian
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Message has 1 Reply:
 | | Re: Inertial guidance
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| I am developing a two axis acceleration sensor that is RCX compatible. Unfortunately, that by itself is not sufficient for inertial navigation in a fixed plane. (i.e. a robot that stays on the floor) A fully inertial system would need a rotational (...) (25 years ago, 12-Jan-02, to lugnet.robotics)
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Message is in Reply To:
| | Re: Inertial guidance
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| (...) The term "inertial guidance" refers to a navigational technique that involves carefully measuring the rotational and translational accelleration of the vehicle, then integrating that to derive the velocity and integrating *that* to get the (...) (25 years ago, 12-Jan-02, to lugnet.robotics)
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