• aditya mehrotra.

learning altium/circuits: building a ROS network compatible motor controller [new project?]

So two things I've always wanted to learn how to design: Arduinos/computers and Motor Controllers. Knowing how to design something like that is interesting to me because then we can build some really creative projects. For example, there are not really any network-based ROS motor controllers on the market that are easy to find or inexpensive enough to use. So what if we were to at least design one, not necessarily build/test but at least theoretically put one together to understand (a) how to use tools like altium designer and (b) how to build a schematic/layout for something like this. It'll help me learn schematics as well.


STEP ONE: Learn the programs w/ a basic project

So I found the schematics for Arduino Online: http://electronoobs.com/eng_arduino_tut31_sch3.php

And from the official site:

https://www.arduino.cc/en/uploads/Main/arduino-uno-schematic.pdf


What I'm going to do is use Altium Designer (preferably) to layout this schematic and then go through it and see what each part is doing. Then hopefully layout a board (what would you want a custom Arduino to look like?)


Once I do that I would prefer to build one and flash the controller and etc but I don't think that will happen right now so I'll move onto the design of the next component until someone can teach me how to flash things after this is all over.


STEP TWO: Designing a ROS-compatible brushless motor controller.



The next question is what would I do with this new-found power of designing electronic systems (kind of). Well I think I'd start by making my own life and the lives of other robotics people so much simpler.


(1) Raspebrry Pi Zero W - a wireless mini linux computer that can run ROS. https://www.raspberrypi.org/documentation/hardware/raspberrypi/schematics/README.md

(2) The VESC 6.5, can handle up to 12s LiPo and 60-80A continuous current up to 150 burst. Perfect for any high-power robotics application that needs brushless motors and ROS. If we combine the VESC motor controlling hardware (just set it to current control mode) and wire and sensors to the Raspberry Pi Zero W (like the encoder), we can create a fusion linux motor controller that runs on ROS.

https://vesc-project.com/sites/default/files/Benjamin%20Posts/VESC_6_plus.pdf


That would be cool. And it's a motor controller that could work over WiFi!!!! How awesome would that be! We'd just need to get rid of any unnecessary components on both devices and add significant cooling. We can also, while we're at it, design a CNC aluminum case for the system!



Even if we don't use VESC we can take components of the VESC design and make the whole thing simpler like in this video. See what comes of that. Even though features of VESC like field oriented control and mapping inputs could come in really handy. I want my controller to have PID Position Control and PID Velocity Control. We can also do trajectories and smart motion.


Definitely going to watch this video as I'll understand the theory behind what I'm trying to do at least someone from this. I'll take notes!


Now: Quick prototype ideas? What would we do to make a quick prototype of the above idea?

(1) We'd acquire a raspberry pi zero w and an ethernet module for the pi zero w or a beagle bone black.

(2) We'd acquire a https://www.amazon.com/Flipsky-Mini-FSESC4-20-Aluminum-Anodized/dp/B07VL7D1WC/ref=sr_1_4?dchild=1&keywords=vesc&qid=1587045952&sr=8-4 Vesc 4.2 for testing.

(3) Raspberry Pi Ethernet Shield for the Pi Zero W.

(4) 8-50v to 5v DC buck converter https://www.amazon.com/SMAKN®-Converter-Voltage-MICRO-USB-Waterproof/dp/B00PXDEZ3C/ref=sr_1_17?dchild=1&keywords=8v-60v+to+5v+converter&qid=1587046293&sr=8-17

(5) Drone PDP and some xt90 connectors (straight parallel connector no converters on the board).


Since that would cost us 160 bucks to do we won't do it now - but we can start working on the allium designs right?


#updates #design #new_projects #ROS_ESC

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