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Re: Robot Arm C

Posted: September 8th, 2011, 6:24 pm
by illusionist
I don not have the rules yet, so are we allowed to use autonomous robots, or is it human-electronic control only?

Re: Robot Arm C

Posted: September 8th, 2011, 6:42 pm
by harryk
blazer wrote:Rule 7d is included.
harryk wrote:I have an idea for an arm with a single motor; using a complex transmission to direct power to different joints, though I think this would prove to be slow, clunky, fragile, and hard to operate, so you probably wouldn't get full points and the advantage of having one motor wouldn't be reaped
Wouldn't you need a second motor to control the transmission?
You manually control the transmission, as far as I know it should be legal since you're not actually powering the arm, only controlling it

Re: Robot Arm C

Posted: September 8th, 2011, 9:22 pm
by 28
what factor will time play in the scoring/tie brakers?

Re: Robot Arm C

Posted: September 8th, 2011, 11:06 pm
by sachleen
harryk wrote:I have an idea for an arm with a single motor; using a complex transmission to direct power to different joints, though I think this would prove to be slow, clunky, fragile, and hard to operate, so you probably wouldn't get full points and the advantage of having one motor wouldn't be reaped
Wouldn't it always move in the same way every time? Meaning, it would extend forward the same amount as it goes down, and back as it goes up. I fail to see how a single motor could be used to make the arm move in different ways.

Re: Robot Arm C

Posted: September 9th, 2011, 6:15 am
by twototwenty
harryk's idea might work if there were two motors, one to power the whole arm and one to switch which piece of the arm the motor was controlling. But to make this type of arm work at all you would need a very high power motor to power the whole arm from one place ( not to metion a very well engineered gear system), and this type of motor would not have enough voltage due to the voltage limits for the competition (unless these limits have been very significantly changed, as I don't ahve the oficial rules yet).

Re: Robot Arm C

Posted: September 9th, 2011, 9:41 am
by sachleen
twototwenty wrote:harryk's idea might work if there were two motors, one to power the whole arm and one to switch which piece of the arm the motor was controlling. But to make this type of arm work at all you would need a very high power motor to power the whole arm from one place ( not to metion a very well engineered gear system), and this type of motor would not have enough voltage due to the voltage limits for the competition (unless these limits have been very significantly changed, as I don't ahve the oficial rules yet).
I think three for the arm and possibly one for the gripper would be a minimum for a practical design. No need to complicate things.
I'd use one to rotate the arm at the base, and have 2 joints. That should allow you to reach anywhere and extend far enough to place objects in the goal box.

Re: Robot Arm C

Posted: September 9th, 2011, 11:34 am
by chalker
28 wrote:what factor will time play in the scoring/tie brakers?
None

Re: Robot Arm C

Posted: September 9th, 2011, 11:45 am
by chalker7
Note that while time doesn't play a direct role in scoring, last year a lot of teams (most, in fact) still ran out of time without attempting to move objects, so you should definitely consider arm speed in your design process.

Re: Robot Arm C

Posted: September 9th, 2011, 1:54 pm
by trp2011
Will cost play a role in scoring?

Re: Robot Arm C

Posted: September 9th, 2011, 1:58 pm
by chalker7
trp2011 wrote:Will cost play a role in scoring?
It will not play a role.