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 Robotics / 19492
19491  |  19493
Subject: 
Re: articulation points?
Newsgroups: 
lugnet.robotics, lugnet.build.mecha, lugnet.technic
Date: 
Wed, 20 Nov 2002 15:03:32 GMT
Viewed: 
1521 times
  
In lugnet.robotics, Eric Sophie writes:

You present interesting aspects of the term, could it be that the term has
many meanings and really if we understood it correctly we would do justice
to the proper meaning. Context is everything, yet you raise ideas and
examples that indeed correspond. Interesting way to put it.

I think you've hit the nail on the head here Eric. To me, the most logical
way of looking at a robot arm would be from the point of view of the end
effector, i.e. what it can and cannot do. The way the arm moves to get there
may be of less concern, or it may not in some cases, I suppose.

Stating n DOF (for large n) seems to be somehow cheating, marketing speak, a
bit like 6 head video recorders! You could have a robot arm where the end
effector only has 4 DOF, yet according to some measures the arm has 6 or
more DOF. To state it is a 6 DOF machine seems misleading, so what then is
the true measure?

This seems to be quite a good guide, they also have the concept of the
"mobility" of a device:

   http://www-2.cs.cmu.edu/People/rapidproto/mechanisms/

How many DOF does a normal tracked vehicle have? What about a Killough platform?

Jennifer



Message has 2 Replies:
  Re: articulation points?
 
(...) Here I go, tossing my 2 cents in to the fray: I would say that any differential drive on a flat surface has 3 DOF: -Assume it drives along the X axis (thats 1) -it can rotate around the Z axis (2 now) -once it rotates it can drive along the y (...) (22 years ago, 18-Nov-02, to lugnet.robotics, lugnet.build.mecha, lugnet.technic)
  Re: articulation points?
 
The main reason it would make sense to quote the total DOF is that is determines the volume the arm needs or is able to work in. For example imagine a snake-bot with a dozen 2 DOF joints. It can reach around objects to position it's effector. So it (...) (22 years ago, 21-Nov-02, to lugnet.robotics, lugnet.build.mecha, lugnet.technic)

Message is in Reply To:
  Re: articulation points?
 
You present interesting aspects of the term, could it be that the term has many meanings and really if we understood it correctly we would do justice to the proper meaning. Context is everything, yet you raise ideas and examples that indeed (...) (22 years ago, 20-Nov-02, to lugnet.robotics)

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