[Dprglist] Recommendations for Robot Platform

[Doug Paradis]

>
> Carl,
>
>     One of the most frequently asked questions by hobbyist roboticists is
> "How can I make an inexpensive robot that I can grow with?". This was the
> quest pursued by the DPRG 2016 Club Robot design. This design also had the
> mantra that it would be built using "goodish" parts that would not need to
> be replaced.
>
>
>
>     A lot was learned from the 2016 Club Robot, and I think that for a
> robot of its size it is a good design. With its separate back and front
> plate assembly feature it is a very configurable. The integral motor cage
> assembly insures good alignment between the motors, making its’ tracking
> very accurate.  The original design uses an Arduino Mega as the main
> processor, which allows beginners an easy entry point to get started. With
> David Anderson's (and Ron Grant) STM32 Nucleo breakout controller board,
> the robot can be upgraded to ARM processors without extreme heart failure.
> Another processor board configuration that includes a Raspberry Pi board is
> the Pololu A-Star 32U4 Robot Controller SV with Raspberry Pi Bridge. The
> chassis design, BOM, and a starting code base is available on DPRG's
> GitHub. There is also a series of videos to show how to build it in its
> original configuration. The motors have encoders.
>
>    The biggest issues with the 2016 Club Robot are:
>
>    1.  The open source code base that we have on GitHub uses
>    David's cooperative scheduling multitasking system, which is not exactly
>    beginner friendly. It is powerful and not overly complex, but I admit that
>    it can sometimes cause problems when troubleshooting. However, this issue
>    could be fixed by adding an alternate code base that didn’t use the
>    cooperative scheduling.
>    2.  The laser cut chassis is not easily obtainable for people without
>    access to a laser cutter. Club members can always have one of the DPRG/DMS
>    members cut one for them for a nominal cost. Laser cut services are also
>    available. Note: You need to make sure your material thickness is the same
>    as the design.
>    3.  The original design's front plate (front halve of robot) could be
>    simplified. Everyone modifies it. I would recommend a special purpose front
>    plate be created based by the roboticist for the desired primary task of
>    the robot.
>
>      I am currently working on a smaller (~6" wheelbase) and simpler robot
> that utilizes features from the 2016 Club Robot design. Its controller
> board is a Raspberry Pi 3A board with a Pololu A-Star 32U4 Robot
> Controller SV hat. This provides motor controllers and a 32U4 (Arduino
> compatible) processor for real time sensor processing. I plan to use the
> Rpi mainly for AI and vision processing. It is powered by the 3500mAh 18650
> batteries that you told me about. I want to use this robot for testing
> Donkey Car code, and as my Challenge LF robot (a different front assembly).
> It uses DFRobot metal gear TTmotor motors with encoders, which I purchased
> from Mouser. If you are interested let me know.
>
>
>
>     There are several off the shelf robot kits that have potential, but
> lack one or more features. I have looked at the kits made by Sunfounder
> (see sunfounder.com or Amazon), they are like a host of kits coming from
> China and elsewhere. The price for these kits is from about $70 to $130.
> They look like they are well thought out, but they are limited by their
> cost constraints. It also depends on what you want to do. They almost
> always lack encoders and use TTmotor TGP yellow motors. Pololu offers kits
> that use "micro" gear motors, these motors are fine for small robots and
> can be had with encoders. The Pololu robots also have excellent
> documentation. I just personally don't like their chassis as general
> robots, but I do own 2, a 3pi and a Balboa.
>
>
>
>     I would be interested in your reason for exploring robot learning
> platforms. If you are looking at STEM activities, I think the Vorpal
> Hexapod robot (search Thingiverse) would be worth considering as a starting
> point to generate interest in robots. If you want a more traditional
> differential robot design, the cheapest way is still the Amazon kit we used
> in the "Build More Robots" training series.
>
>
>
>     Let's talk at RBNO.
>
>
>
> Regards,
>
> Doug P.
>
>
>
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