Difference between revisions of "DEWBOT X Ball Handling"

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While the Roller Frame itself is a simple mechanism, a great deal of mind-time went into the details of its design; especially in terms of materials selection, roller drive, specific geometry and mounting arrangements.  Minding those details ended up making a huge difference, especially in reliability & durability.
 
While the Roller Frame itself is a simple mechanism, a great deal of mind-time went into the details of its design; especially in terms of materials selection, roller drive, specific geometry and mounting arrangements.  Minding those details ended up making a huge difference, especially in reliability & durability.
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==Description==
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The system consists of two components: the '''Roller Frame''' and the '''Boot'''.
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The '''Roller Frame''' is a U-frame open and anchored to the chassis with a pivot joint at the bottom.  There are three main structural elements: the sides and the bottom (at the top) of the "U". These three structural elements are connected to each other via (4) bolted 6061 Al gussets.  One of these gussets (left-rear) also serves as a motor mount.
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The '''Roller Frame''' is anchored to the chassis weldment via a custom welded 3/8" steel roller pin secured with an e-clip.  The roller pin passes through a custom pillow block with a bronze bushing securely bolted to the chassis weldment (via 1/4"-20 SHCS's and rivet nuts).  As originally built, the pillow block was a purchased COTS item (McMaster-Carr 5912K3), but the sintered aluminum proved to be brittle and failed repeatedly during testing.  The COTS pillow block was replaced with a CNC-machined 6061 Al block which has held up to competition service.
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==Materials==
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==Drive & Clutch==
  
  

Revision as of 12:04, 4 May 2014

Loading ball in autonomous
The team designed a very effective Roller Frame to control ball movement. While originally envisioned primarily for the purpose of picking the ball up off of the floor, the finished system performed the following functions:
  • Rapidly gaining control of the ball on the floor and loading it into the robot's shooter
  • Holding the ball securely in the shooter during aggressive play and maneuvers
  • "Packing" the ball into the shooter to facilitate accurate shooting
  • Rolling the ball out of the shooter and passing to an alliance robot
  • Passing directly to an alliance robot as an inbounder
  • Rolling the ball out of the shooter and scoring into the low goal
  • Loading the ball into the shooter at the start of autonomous
  • Facilitating catching the ball - from a truss shot (rare) or from a human player (very common)

A lot of utility for a single, simple mechanism!

As the only part of DEWBOT X to extend beyond the frame perimeter, the Roller Frame was also subject to an enormous amount of physical abuse. The design had to accommodate this.

While the Roller Frame itself is a simple mechanism, a great deal of mind-time went into the details of its design; especially in terms of materials selection, roller drive, specific geometry and mounting arrangements. Minding those details ended up making a huge difference, especially in reliability & durability.

Description

The system consists of two components: the Roller Frame and the Boot.

The Roller Frame is a U-frame open and anchored to the chassis with a pivot joint at the bottom. There are three main structural elements: the sides and the bottom (at the top) of the "U". These three structural elements are connected to each other via (4) bolted 6061 Al gussets. One of these gussets (left-rear) also serves as a motor mount.

The Roller Frame is anchored to the chassis weldment via a custom welded 3/8" steel roller pin secured with an e-clip. The roller pin passes through a custom pillow block with a bronze bushing securely bolted to the chassis weldment (via 1/4"-20 SHCS's and rivet nuts). As originally built, the pillow block was a purchased COTS item (McMaster-Carr 5912K3), but the sintered aluminum proved to be brittle and failed repeatedly during testing. The COTS pillow block was replaced with a CNC-machined 6061 Al block which has held up to competition service.

Materials

Drive & Clutch