Difference between revisions of "DEWBOT XIII Shooter"
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==Shooter== | ==Shooter== | ||
+ | The shooter is a basic single-wheel shooter. While simple, this mechanism went through an enormous amount of testing and development, including multiple prototypes, the last few being CNC-produced. | ||
+ | |||
+ | Some key learnings: | ||
+ | * A flywheel reduces the magnitude of speed reduction while shooting, but not recovery time | ||
+ | * More power reduces speed recovery time | ||
+ | * Holes in balls (fuel) interacting randomly with thin shooter rails randomly throw off ball trajectory | ||
+ | * 6 inch wheels provide more consistency than 4 inch | ||
+ | * 2 inch wide wheels provide more consistency than 1 inch wide | ||
+ | * Printed guides expanding the ball contact area from narrow rails to >1/3<sup>rd</sup> circumference, thereby improving shooting consistency | ||
+ | |||
+ | Key design features: | ||
+ | * PID controlled wheel speed | ||
+ | * 3:1 reduction via 1-stage versaplanetary gearbox | ||
+ | * Up to (3) 775 Pro drive motors | ||
+ | * Adjustable shooting trajectory 60-85° from horizontal - adjustment via a quarter scale (large) servo. The servo drives a 14T gear (20 DP - 14° contact angle) which drives an 84T half gear on the trajectory hood. A 180° rotation of the servo rotates the trajectory hood by 30°. | ||
+ | * Trajectory hood rotates co-axially with shooter wheel axle. | ||
+ | |||
+ | As of FRC Championship, we seem to have a shooter capable of shooting ~6 balls/s with good accuracy. We, however, are not able to feed this shooter consistently at this rate. As a result, shooting rate is erratic. | ||
<gallery widths=250 heights=250 perrow=3> | <gallery widths=250 heights=250 perrow=3> | ||
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image:DB13_170114-12.jpg|next prototype | image:DB13_170114-12.jpg|next prototype | ||
image:DB13_170114-13.jpg| | image:DB13_170114-13.jpg| | ||
− | image:DB13_shooter_170119.jpg|early CAD | + | image:DB13_shooter_170119.jpg|early CAD with CIM drive |
image:DB13_shooter_170121.jpg|Double shooter CAD | image:DB13_shooter_170121.jpg|Double shooter CAD | ||
image:DB13_170121-4.jpg|Aashay & Gary | image:DB13_170121-4.jpg|Aashay & Gary | ||
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image:DB13_170122-3.jpg| | image:DB13_170122-3.jpg| | ||
image:DB13_170122-5.jpg| | image:DB13_170122-5.jpg| | ||
− | image:DB13_shooter_170126.jpg|CAD of duplex shooter | + | image:DB13_shooter_170126.jpg|CAD of duplex shooter - now using 775 Pro motor w/ 3:1 reduction |
image:DB13_170128-1.jpg|Shooter frame | image:DB13_170128-1.jpg|Shooter frame | ||
image:DB13_170129-6.jpg| | image:DB13_170129-6.jpg| | ||
image:DB13_170129-7.jpg| | image:DB13_170129-7.jpg| | ||
image:DB13_170203-1.jpg|CAD showing early elevation adjustment hood | image:DB13_170203-1.jpg|CAD showing early elevation adjustment hood | ||
− | image:DB13_170203-17.jpg| | + | image:DB13_170203-17.jpg|Shooter with double 775 Pro drive |
image:DB13_170204-7.jpg| | image:DB13_170204-7.jpg| | ||
image:DB13_shooter_170208.jpg|CAD with revised elevation hood | image:DB13_shooter_170208.jpg|CAD with revised elevation hood | ||
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image:DB13_170219-7.jpg|Shooter mounted | image:DB13_170219-7.jpg|Shooter mounted | ||
image:1640 2017 Shooter.png|Shooter with printed guides in place | image:1640 2017 Shooter.png|Shooter with printed guides in place | ||
+ | image:DB13_shooter-5.jpg|6 inch flywheel | ||
+ | image:DB13_shooter-6.jpg|3-motor (750 Pro) shooter gearbox | ||
+ | image:DB13_shooter-9.jpg|3-motor shooter w/ 6" flywheel in ''deux'' | ||
</gallery> | </gallery> | ||
==Feeder== | ==Feeder== | ||
+ | <gallery widths=250 heights=250 perrow=3> | ||
+ | image:DB13_170118-4.jpg|Hopper tests | ||
+ | image:DB13_170121-5.jpg|prototype | ||
+ | image:DB13_170121-8.jpg|testing | ||
+ | image:DB13_170124-2.jpg| | ||
+ | image:DB13_170124-3.jpg| | ||
+ | image:DB13_170125-2.jpg| | ||
+ | image:DB13_170126-3.jpg| | ||
+ | image:DB13_170128-6.jpg| | ||
+ | image:DB13_170128-14.jpg|First rotor-type prototype | ||
+ | image:DB13_170128-17.jpg| | ||
+ | image:DB13_170128-18.jpg| | ||
+ | image:DB13_170131-1.jpg|Rotors | ||
+ | image:DB13_170210-1.jpg| | ||
+ | image:DB13_170218-40.jpg| | ||
+ | image:DB13_170219-11.jpg| | ||
+ | image:DB13_170219-14.jpg| | ||
+ | image:DB13_170220-22.jpg| | ||
+ | </gallery> | ||
==Ball Pickup== | ==Ball Pickup== |
Latest revision as of 10:30, 11 May 2017
It had been the team's intention and strategy for DEWBOT XIII to be a high-performance shooter (together with good rear running capabilities and a fast, reliable climb). Alas, we did not accomplish the critical shooting goal. Our shooter was definitely middling. While very consistent in its shooting and capable of shooting consistently at up to 6 balls/s, feed issues limited us to an average 2.5 balls/s. In addition, while shooter elevation and wheel speed are adjustable,we had a limited number of pre-set shooting solutions and limited objective data on which to base such solutions.
The Shooter System comprises several interacting components:
- Shooter
- Feeder
- Ball Pickup
- Hopper
Contents
Shooter
The shooter is a basic single-wheel shooter. While simple, this mechanism went through an enormous amount of testing and development, including multiple prototypes, the last few being CNC-produced.
Some key learnings:
- A flywheel reduces the magnitude of speed reduction while shooting, but not recovery time
- More power reduces speed recovery time
- Holes in balls (fuel) interacting randomly with thin shooter rails randomly throw off ball trajectory
- 6 inch wheels provide more consistency than 4 inch
- 2 inch wide wheels provide more consistency than 1 inch wide
- Printed guides expanding the ball contact area from narrow rails to >1/3rd circumference, thereby improving shooting consistency
Key design features:
- PID controlled wheel speed
- 3:1 reduction via 1-stage versaplanetary gearbox
- Up to (3) 775 Pro drive motors
- Adjustable shooting trajectory 60-85° from horizontal - adjustment via a quarter scale (large) servo. The servo drives a 14T gear (20 DP - 14° contact angle) which drives an 84T half gear on the trajectory hood. A 180° rotation of the servo rotates the trajectory hood by 30°.
- Trajectory hood rotates co-axially with shooter wheel axle.
As of FRC Championship, we seem to have a shooter capable of shooting ~6 balls/s with good accuracy. We, however, are not able to feed this shooter consistently at this rate. As a result, shooting rate is erratic.