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Re: Robot Arm C
Posted: May 3rd, 2012, 5:28 pm
by scm424
Where might a beginner learn how to build robots?
Re: Robot Arm C
Posted: May 3rd, 2012, 7:41 pm
by twototwenty
If you are a complete beginner, I would recommend getting the owi kit, espescially if you don't have much to spend, builing it with the instructions, then designing the necessary extensions for it to make it long enough. My team did that, and it ended up placing 3rd at my regionals, and that was with minimal practice. Of course, this only works for lower levels of the competition.
Re: Robot Arm C
Posted: May 3rd, 2012, 8:13 pm
by mrsteven
scm424 wrote:Where might a beginner learn how to build robots?
I'm still learning as I'm going. depending on how in depth you want to go with the design from a basic one to a more complicated requires-coding type systems. To my knowledge there isn't a singular guide to help but if you know some principles and basic idea on function, many schools engineering teachers will help you figure out how to assembly logistically and if required, help with coding
OWI is what I started off with, it can be very helpful with learning the ideas of how one should function to abed further development. Also if you really want to you can steal the board from it and use the controls with another bot with similar motors
Re: Robot Arm C
Posted: May 5th, 2012, 7:27 pm
by twototwenty
What strength (torque) servos are you guys using, in particular for the "elbow", "shoulder" and overall rotation joints?
Re: Robot Arm C
Posted: May 7th, 2012, 5:27 pm
by iwonder
If properly counterweighted, I've used the HS-645MG(133oz in) for the secondary axis(elbow), and could possibly use it for the primary, however I use a HS-805MG in a geared configuration for the main axis(shoulder) which is rated at 1715oz in of torque, this is a little crazy for a normal sized arm, but mines about twice the size it needed to be
. I use another HS-645 in the base, but I've shredded the gears twice(small gear teeth...) and before I broke the mechanical stop on a karbonite servo(HS-485HB). I do have an HS-7950TH that I've put in the base and it works well(a little overshoot, but the servo controls it) that is rated for 402oz in@6v(titanium gears) however it's not very smooth to control so I can't use it in competition.
Re: Robot Arm C
Posted: May 20th, 2012, 5:12 am
by harryk
So, anybody know how many perfect scores there were at Nats? Chalkers?
Re: Robot Arm C
Posted: May 20th, 2012, 5:22 am
by chalker7
harryk wrote:So, anybody know how many perfect scores there were at Nats? Chalkers?
6
Re: Robot Arm C
Posted: May 20th, 2012, 8:46 am
by illusionist
chalker7 wrote:harryk wrote:So, anybody know how many perfect scores there were at Nats? Chalkers?
6
How about least number of motors used? (I'm guessing Mr. Anderson would have to answer this one)
And also, how difficult was it to break a tie using the quality of the technical drawings?
Re: Robot Arm C
Posted: May 20th, 2012, 8:56 am
by AlphaTauri
I heard there was a 3-motor one, but it didn't get as good a score as the 4-motor arms.
Re: Robot Arm C
Posted: May 20th, 2012, 10:48 am
by FueL
All the robots that got perfect scores used 4 (or possibly more) motors. I think LASA had a 3 motor arm, but it didn't get a perfect.