Drill Motor Anti-reverse Pins...

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Posted by Ken.

Student on team #192, Gunn Robotics Team, from Henry M. Gunn Senior High School.

Posted on 2/17/2000 12:32 AM MST




What are the advantages and disadvantages for taking out the Anti-reverse pins in the drill motor gearbox?

Can anyone help us?

Ken L.

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Posted by Daniel.

Coach on team #483, BORG, from Berkeley High School and NASA Ames & UC Berkeley.

Posted on 2/17/2000 12:50 AM MST


In Reply to: Drill Motor Anti-reverse Pins... posted by Ken on 2/17/2000 12:32 AM MST:



When you have a 130 pound robot moving along at a pretty decent clip, and it runs into something...those pins will lock up and all the impact will be transfered through the tabs that the shaft wings fit between. If those break, you're dead. Without those pins, you're fighting the motor instead of the internal mechanisms. This is a MUCH better way to go. From all I've heard and from what I've seen, those pins should be removed asap. We ditched ours.

It's also kinda nice if you want to be able to push your robot around instead of having to break your back.

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Posted by Ken.

Student on team #192, Gunn Robotics Team, from Henry M. Gunn Senior High School.

Posted on 2/18/2000 2:03 AM MST


In Reply to: ditch 'em posted by Daniel on 2/17/2000 12:50 AM MST:



: When you have a 130 pound robot moving along at a pretty decent clip, and it runs into something...those pins will lock up and all the impact will be transfered through the tabs that the shaft wings fit between. If those break, you're dead. Without those pins, you're fighting the motor instead of the internal mechanisms. This is a MUCH better way to go. From all I've heard and from what I've seen, those pins should be removed asap. We ditched ours.

One thing:

When we take out the pin and the robot is on the ramp, the robot slide down from the ramp. This would make it pretty hard to take over the ramp.

Ken L.

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Posted by Daniel.

Coach on team #483, BORG, from Berkeley High School and NASA Ames & UC Berkeley.

Posted on 2/18/2000 2:49 AM MST


In Reply to: Re: ditch 'em posted by Ken on 2/18/2000 2:03 AM MST:



You could try setting the jumper on the speed controller to electronic breaking. I actually think that may not be enough to stop you from rolling down but it's worth a try.

-DL

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Posted by Daniel.

Coach on team #483, BORG, from Berkeley High School and NASA Ames & UC Berkeley.

Posted on 2/18/2000 3:35 AM MST


In Reply to: Re: ditch 'em posted by Daniel on 2/18/2000 2:49 AM MST:



Don't follow my advice without using the right precautions!!

If you don't have a ramped deceleration programmed in for the drill motors....you're gonna go straight to break after you stop powering the drill motor. That would be BAD. I know you guys so I know you'll have it but I just wanted to make sure you don't try it witout a programmed decelearation.

-DL

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Posted by Dodd Stacy.

Engineer on team #95, Lebanon Robotics Team, from Lebanon High School and CRREL/CREARE.

Posted on 2/18/2000 6:12 AM MST


In Reply to: warning!! posted by Daniel on 2/18/2000 3:35 AM MST:




: If you don't have a ramped deceleration programmed in for the drill motors....you're gonna go straight to break after you stop powering the drill motor....

This reminds me of a dumb question I've been meaning to ask: Do the drill motors (or any other motors) produce more decelerating torque in the dynamic braking mode than they do in the accelerating mode?

Except for gearbox friction, etc adding to braking torque vs subtracting from accelerating torque, I can't see any reason why a motor would make a more powerful generator than it is a motor. Unless maybe the generated voltage in the dynamic braking mode is allowed to go much higher than 12V? (or the current in the windings to go much higher) Can anyone help me out with this? Thanks.

Dodd