From e0c6872cf40896c7be36b11dcc744620f10adf1d Mon Sep 17 00:00:00 2001 From: Norbert Preining Date: Mon, 2 Sep 2019 13:46:59 +0900 Subject: Initial commit --- macros/latex/contrib/ftc-notebook/src/aug19.tex | 210 ++++++++++++++++++++++++ 1 file changed, 210 insertions(+) create mode 100644 macros/latex/contrib/ftc-notebook/src/aug19.tex (limited to 'macros/latex/contrib/ftc-notebook/src/aug19.tex') diff --git a/macros/latex/contrib/ftc-notebook/src/aug19.tex b/macros/latex/contrib/ftc-notebook/src/aug19.tex new file mode 100644 index 0000000000..3cd4f7875e --- /dev/null +++ b/macros/latex/contrib/ftc-notebook/src/aug19.tex @@ -0,0 +1,210 @@ + \begin{Meeting}[Preseason] + {Programming Chassis Suitable to Test Localization} + {August 19-25} + {20 hours} + {\Signee{Nicolas}, \Signee{Zachary}} + { + \TaskInfo{First Iteration Mecanum Drive Module} + {aug19: programming chassis first draft} + {First attempt at lightweight chassis, worked well but could be made more compact} + \TaskInfo{Second Iteration Mecanum Drive and Integration into Chassis} + {aug19:programming chassis second draft} + {Second attempt is more compact and stronger} + } + +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +% meeting summary, or meeting goal +% high level description of the goal of the meeting, in a paragraph following the command +\MeetingSummary + +The goal of this week is to develop new technology for the season. We +focus on Mecanum wheels, which we have not used for a long time. Our +immediate goal is design a platform to learn to program encoder +wheels. We also want to gain experience in using bear motors, namely +motors without internal gear boxes. + +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +% NEW TASK: First Iteration Mecanum Drive Module +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% + + %1 Strategy; 2 Design; 3 Build; 4 STEM; 5 Software; 6 Team +\Task{2}[3] + +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +\Section{Goals} +\begin{itemize} + \item Design a mecanum chassis to use for testing localization and autonomous driving. + \item Use the chassis to validate (or invalidate) new design ideas (bare motor drivetrain). + \item Low cost. + \end{itemize} + +\Section{Design Process} + +First, we plan components to use for the drive train. We do so by +first considering our design goals for this robot in order of +importance, then assessing how we can best accomplish these +goals. Often, one design choice can satisfy many factors +simultaneously. + +\begin{DescriptionTable}{Factors}{Solutions}% + {Design goals for the programming chassis}{table:aug19:goals} + % + \TableEntryTextItem{Testing New Designs} + { + \item Incorporate odometry wheels (for position tracking) + \item Prototype use of motors without gearboxes (With external reduction) + \item Test mecanum wheels + } \\ \hline + % + \TableEntryTextItem{Low Cost} + { + \item Use motors without gearboxes: this will allow us to use + our classic Neverest 20 motors (which we decommissioned due to + their fragile gearboxes). + \item Design with mostly plywood, EuroBoard, and 3d printed parts. + \item Use Nexus mecanum wheels (already on hand). + \item Use EMS22Q Bourns encoder for odometry wheels (least + expensive compatible encoder that satisfies the design + constraints). } \\ \hline + % + \TableEntryTextItem{Analogous to Typical Competition Robots} + { + \item Make the robot lightweight, so we can add weight to match + any future robot?s weight for testing + \item Use Mecanum wheels (we already have test tank chassis, and + are looking to experiment with mecanum) } + % +\end{DescriptionTable} + + +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +\Section{CAD and Build} + +A complete chassis requires 4 identical wheel modules, which contain a +mecanum wheel and its motor. The CAD model is shown in +\FigureRef{aug19:first cad}. We CNCed the parts as well as 3D printed +the large pulley. The result is shown in \FigureRef{aug19:first + build}. + +\ExplainedPictFigure{src/aug19/first-cad.jpg}[0.4]% + {CAD model of mecanum wheel module (first iteration)}{aug19:first cad} + { + \begin{compactitem} + \item Nexus mecanum wheel + \item Single belt reduction from bare motor to wheel + \item Adjustable tensioner pulley + \item EuroBoard side plates + \item Churro standoffs + \item Extremely compact + \end{compactitem} + } + +\PictFigure{src/aug19/first-build.jpg}[0.4]% + {Prototype of mecanum wheel module (first iteration)}{aug19:first build}% + [\Callout{-8, 4}{Unsupported Idle Pulley}{-0.5, -0.5}] + +\begin{DescriptionTable*}{Works}{Need Improvement}% + {Conclusion after first build}{table:aug19:improvement} + % + \TableEntryItemItem{ + \item Wheel runs smoothly + \item Press fit bearings in wheel work flawlessly + \item Motor standoffs work well + \item EuroBoard is a fantastic prototyping material - cuts easily on the CNC + } { + \item Cantilevered idler bearing deforms the EuroBoard under load - % + needs support from both sides + \item EuroBoard is not very strong - not suitable for competition % + robot drivetrain, but works for light + } +\end{DescriptionTable*} + + +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +\Section{Conclusion} + +The module looks promising, and has already successfully demonstrated +the effectiveness of using EuroBoard as a prototyping material, though +we should avoid using it structurally on a competition robot. The +idler pulley needs to be redesigned with support on either side, and +we can likely make the entire module even more compact by using a +slightly shorter belt! + + +With these small modifications, the module is ready to be used on the +programming chassis. We now need to design the chassis itself, as well +as mounting points for all the sensors. + + +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +% NEW TASK Second Iteration Mecanum Drive and Integration into Chassis +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% + +\Task[\TaskRef{aug19: programming chassis first draft}]{2}[3] + +\Section{Goals} +\begin{itemize} + \item Suggested improvements from \TaskRef{aug19: programming chassis first draft}. + \item Design odometry wheel modules. + \item Design complete chassis. +\end{itemize} + +\newpage + +\Section{Design} + +Using the feedback from \TaskRef{aug19: programming chassis first + draft}, we redesigned the CAD model for the wheel module, shown in +\FigureRef{aug19:second cad}. We reused an odometry design, shown in +\FigureRef{aug19:odometry cad}. The full chassis consists of 4 wheel +modules and 3 odometry modules. The Chassis CAD is shown in +\FigureRef{aug19:chassi cad}. + +We CNCed the parts as well as 3D printed the large pulley. The result +is shown in \FigureRef{aug19:first build}. + +\ExplainedPictFigure{src/aug19/second-cad.jpg}[0.4]% + {CAD model of mecanum wheel module (second iteration)}{aug19:second cad} + { + Improvements: + \begin{compactitem} + \item Idler Bearing supported from both sides + \item Shorter plate layout + \item Slightly smaller pulley on the wheel to avoid scraping on the mat + \end{compactitem} + } + +\ExplainedPictFigure{src/aug19/encoder-cad.jpg}[0.4]% + {CAD model of odometry wheel}{aug19:odometry cad} + { + Features: + \begin{compactitem} + \item 38mm omniwheel + \item 1024 ppr direct mounted encoder + \item Shielding to protect encoder + \item Spring-loaded against the mat for improved reliability + \item Accurate mounting holes + \end{compactitem} + } + +\ExplainedPictFigure{src/aug19/chassi-cad.jpg}[0.4]% + {CAD of entire Chassis}{aug19:chassi cad} + { + Features: + \begin{compactitem} + \item Lightweight simple chassis + \item Fast Mecanum wheel base + \item 3 odometry omniwheels + \item 2 light sensors facing the mat + \item Plywood base - easy to manufacture + \end{compactitem} + } + + \PictFigure{src/aug19/build-pict.jpg}[0.7]% + {Building of full chassis (second iteration)}{aug19:second build} + + +\end{Meeting} + + + -- cgit v1.2.3