Difference between revisions of "Provisional Dewbot V Chassis"
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Drive-train is [[6wd]] Tank. Middle wheels are directly driven by the gearbox. Fore and aft wheels are slave-chain driven from the middle wheels. This arrangement provides reliability, as the loss of any one drive chain (a common problem with [[DEWBOT III]] and [[DEWBOT IV]], but so far never an issue with [[DEWBOT V]]) would have a minimal impact on robot mobility. | Drive-train is [[6wd]] Tank. Middle wheels are directly driven by the gearbox. Fore and aft wheels are slave-chain driven from the middle wheels. This arrangement provides reliability, as the loss of any one drive chain (a common problem with [[DEWBOT III]] and [[DEWBOT IV]], but so far never an issue with [[DEWBOT V]]) would have a minimal impact on robot mobility. | ||
| − | Fore and aft wheels are anchored in Bearing Block Assemblies bolted into 80/20 1010 channel. The Bearing Block Assemblies contain ½" ID flangeless ball bearing assemblies. Bearing Block Covers retain the bearing races. By mounting the Bearing Block Assemblies on 80/80 1010 profile, adjusting wheel position to maintain chain tension is straightforward. | + | Fore and aft wheels are anchored in Bearing Block Assemblies bolted into 80/20 1010 channel. The Bearing Block Assemblies contain ½" ID flangeless ball bearing assemblies. Bearing Block Covers retain the bearing races. By mounting the Bearing Block Assemblies on 80/80 1010 profile, adjusting wheel position to maintain chain tension is straightforward. View pdf format [[Media:Hypothetical_6wd_wheel_bearing_block_2008.pdf | bearing block drawings]]. |
Middle wheels have no bearing blocks. Their drive shafts are cantalievered from the gearboxes. | Middle wheels have no bearing blocks. Their drive shafts are cantalievered from the gearboxes. | ||
| − | ===Direct-Drive Gearbox=== | + | Type 35 steel chain is used. Each of the (4) chain circuits has 102 links. |
| + | |||
| + | ====wheels==== | ||
| + | |||
| + | ====Direct-Drive Gearbox==== | ||
===Attention to Servicability=== | ===Attention to Servicability=== | ||
Revision as of 19:58, 14 June 2009
Based on what the team learned during prototype testing in summer of 2008, and subsequent drive-train analysis, a Provisional 6wd drive-train and chassis was designed during the Fall with the expectation of using this for DEWBOT V. A great deal of thought and analysis went into this design (as the urgencies of build season were absent). In the end, this design was not built owing to the unique attributes of FRC's Lunacy competition. The effort was not wasted, however, as the thought processes and analyses employed in this design were swiftly put to good use in designing DEWBOT V's chassis and drive-train. Many of the design features described here found a home in DEWBOT V.
Contents
Overview
Design is a traditionally-oriented (long) 6wd FRC Chassis fitting the typical FRC starting envelope (38" x 28").
Key objectives in this design were:
- A maneuverable, stable, fast, reliable, high-traction and high-power chassis
- Provide logical, protected & servicable space for electronic and pneumatic systems
- Provide a clear platform for scoring systems
- Build servicability into the design from the start (make it front-of-mind)
- Keep high-precision custom machined components to a minimum
- Manage weight
- Did I already say reliable? A robot with an unreliable drive-train spends a lot of very embarasing time sitting still in competition. Been there. Done that.
Design Details
View the pdf format chassis drawings.
Open the Microsoft Excel Drive-train Model.
Drive-train
Drive-train is 6wd Tank. Middle wheels are directly driven by the gearbox. Fore and aft wheels are slave-chain driven from the middle wheels. This arrangement provides reliability, as the loss of any one drive chain (a common problem with DEWBOT III and DEWBOT IV, but so far never an issue with DEWBOT V) would have a minimal impact on robot mobility.
Fore and aft wheels are anchored in Bearing Block Assemblies bolted into 80/20 1010 channel. The Bearing Block Assemblies contain ½" ID flangeless ball bearing assemblies. Bearing Block Covers retain the bearing races. By mounting the Bearing Block Assemblies on 80/80 1010 profile, adjusting wheel position to maintain chain tension is straightforward. View pdf format bearing block drawings.
Middle wheels have no bearing blocks. Their drive shafts are cantalievered from the gearboxes.
Type 35 steel chain is used. Each of the (4) chain circuits has 102 links.
wheels
Direct-Drive Gearbox
Attention to Servicability
Legacy in DEWBOT V
