Pick motors for robot

[rhauch]

This of course depends upon the design, but we can start documenting which motors we think we might wan to for the different aspects of each design (as needed).

[rhauch]

Latest design uses two arms with powered rollers (one on each side of the ball, roller axes are vertical) and propel the ball away from the robot. The rollers would have a high-friction surface (e.g., plaction material) and would be geared together and have a single motor per arm. The rollers would rotate slowly to pull in the ball between the arms and would stop when the ball is near the rear of the robot. To release, rotate the rollers in the opposite direction to push the ball down the arms and away from the robot. The arms would rotate vertically (up to shoot, down to pick up a robot).

The RS775 Motor (am-0915) with PG27 planetary gear box might be a good choice to power the rollers. It's relatively small, with a 26.9:1 gear reduction resulting in a free-load RPM of 198; this is in the range where, with no load, 2.5" diameter rollers (circumference of 7.85") would provide a surface speed of about 2.15 ft/sec) with no additional gearing. This motor has decent torque.

[Polluxium]

We can use the AndyMark PG71 gearbox with RS775 motor (am-0914) (the little motor with the attached gearbox) for the conveyer mechanism movement. If we were to use a 1 inch gear on the link axle (controls the movement of BOTH conveyer mechanisms) then we could use this motor and still pull the conveyer with ~96 lbs of force (IF the chain is mounted on the conveyer ~21 inches above the link axle with the chain mounted ~30 inches away from the gear). And that is just with one motor+gearbox. We could use two motor+gearboxes, and double the force applied. One drawback is that the am-0914 weighs almost 2 pounds.

[rhauch]

We've approaching a complete design for the competition robot, and have reduced the number of motors to:

• 4 CIMs for drive train
• 1 motor for the roller on the drop-down capture arm (maybe the PG27 Planetary Gearbox with RS775 Motor (that has 192 rpm, or about 3.2rev/sec). Even though we have one of the motors, AndyMark doesn't seem to sell just the PG27 Planetary Gearbox by itself.
• Potentially another motor for the net arms, though we're hoping to use pneumatics.

We now think that we're going to use pneumatics to raise/lower the drop-down capture arm. We only need two positions: up and down. There should be little resistance (other than gravity, accidental collision with other robot) to raising the capture arm, and we'd want to lower it when there is and is not a ball in the way. The ball will provide resistance, but the roller should be spinning (to move the ball into the robot), and we can control how much down-force the pneumatics place on the arm.

[randej]

The planetary gearbox by itself is available from BaneBots.

Refer to the JVN motor calcs spreadsheet for more information and help on selecting motors.

We will need pneumatic cylinders and solenoids to complete robot. We should have all other components (other than maybe another low-side regulator and gauge). @randej can order the latter from AndyMark.

Rande J.

On Jan 23, 2014, at 9:47 AM, Randall Hauch notifications@github.com wrote:

We've approaching a complete design for the competition robot, and have reduced the number of motors to:

4 CIMs for drive train 1 motor for the roller on the drop-down capture arm (maybe the PG27 Planetary Gearbox with RS775 Motor (that has 192 rpm, or about 3.2rev/sec). Even though we have one of the motors, AndyMark doesn't seem to sell just the PG27 Planetary Gearbox by itself. Potentially another motor for the net arms, though we're hoping to use pneumatics. We now think that we're going to use pneumatics to raise/lower the drop-down capture arm. We only need two positions: up and down. There should be little resistance (other than gravity, accidental collision with other robot) to raising the capture arm, and we'd want to lower it when there is and is not a ball in the way. The ball will provide resistance, but the roller should be spinning (to move the ball into the robot), and we can control how much down-force the pneumatics place on the arm.

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[rhauch]

@randej, see issue #32 for obtaining the pneumatic cylinders and solenoids. We won't create an issue for the regulator and gage, which we can probably obtain pretty easily.

[randej]

Two sizes available at 6": 3/4" or 1 1/16" bores.

3/4 provides 13 lbs of force at 30 psi, the larger one is 26 lbs. Preference? I'm think larger since it's not that much heavier/bigger and offers twice the force (we need to plan at least 25% extra for light loading).

Rande J.

On Jan 23, 2014, at 9:57 AM, Randall Hauch notifications@github.com wrote:

@randej, see issue #32 for obtaining the pneumatic cylinders and solenoids. We won't create an issue for the regulator and gage, which we can probably obtain pretty easily.

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[rhauch]

Larger is probably fine. We'll just have to be sure it's not physically too large to obstruct the ball falling down into the interior of the robot after catching.

[rhauch]

We have 4 CIMs for the chassis, 2 window motors from Team 1208 for the rear net arms, and for the roller arm one Banebots P60K-44-0004 gearbox for use with one of the AndyMark motors.

[randej]

May not want to close this one yet - we want to make sure the roller motor can do the job. Looks like BaneBots gearboxes need a break in period, see

http://www.chiefdelphi.com/forums/showthread.php?t=103884&highlight=BaneBots+gearbox+grease

Rande J.

On Feb 4, 2014, at 10:50 AM, Randall Hauch notifications@github.com wrote:

Closed #19.

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[rhauch]

Do we need to order some extra pinions, per the above forum discussion?

[randej]

Possibly. Not sure how many we got with motor. We do have second motor and wouldn't hurt to have it ready to go.

May also need to check grease we have. May need another type unless running this for awhile does the trick. I'm going to ask Triad and O'Fallon for advice.

Rande J.

On Feb 4, 2014, at 11:42 AM, Randall Hauch notifications@github.com wrote:

Do we need to order some extra pinions, per the above forum discussion?

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