6 ms·

This is very exciting! For the last several years I have been developing a brushless motor driver based on the RP2040 [1]. The driver module can handle up to 53

This is very exciting! For the last several years I have been developing a brushless motor driver based on the RP2040 [1]. The driver module can handle up to 53 volts at 30A continuous, 50A peak. I broke the driver out to a separate module recently which is helpful for our farm robot and is also important for driver testing as we improve the design. However this rev seems pretty solid, so I might build a single board low cost integrated single motor driver with the RP2350 soon! With the RP2040 the loop rate was 8khz which is totally fine for big farm robot drive motors, but some high performance drivers with floating point do 50khz loop rate. My board runs SimpleFOC, and people on the forum have been talking about building a flagship design, but they need support for sensorless control as well as floating point, so if I use the new larger pinout variant of the RP2350 with 8 ADC pins, we can measure three current signals and three bridge voltages to make a nice sensorless driver! It will be a few months before I can have a design ready, but follow the git repo or my twitter profile [2] if you would like to stay up to date! [1] https://github.com/tlalexander/rp2040-motor-controller https://github.com/tlalexander/rp2040-motor-controller [2] https://twitter.com/TLAlexander https://twitter.com/TLAlexander

sgu999 2y ago
> for our farm robot That peaked my interest, here's the video for those who want to save a few clicks: https://www.youtube.com/watch?v=fFhTPHlPAAk https://www.youtube.com/watch?v=fFhTPHlPAAk I absolutely love that they use bike parts for the feet and wheels.
- HeyLaughingBoy 2y ago
  I have given some thought to a two-wheeled electric tractor for dealing with mud -- horse paddocks turn into basically a 1-foot deep slurry after heavy rain and it can be easier to deal with something small that sinks through the mud, down to solid ground than something using large floatation tires. Additional problem with large tires is that they tend to throw mud around, making everyone nearby even more dirty. I haven't actually built anything (been paying attention to Taylor's work, though), but I came to the same conclusion that bike wheels & tires would probably be a good choice. It also doesn't hurt that we have many discarded kids' bikes all over the place.
  - littlestymaar 2y ago
    Your description fit what I've seen for rice farming, whose machines usually use bike-like tires.
    - vintagedave 2y ago
      I’m curious there. I’ve seen rice paddies plowed in Vietnam and the tractors used wide paddle-like wheels. I saw two varieties: one with what looked like more normal wheels but much wider, and one which was of metal with fins, very much akin to a paddle steamer, though still with some kind of flat surface that must have distributed weight. Would they be more effective with thin wheels? Both humans and cattle seem to sink in a few inches and stop; I don’t know what’s under the layer of mud and what makes up a rice paddy.
      - littlestymaar 2y ago
        What I saw was in Taiwan, but I guess it must depends on the depth of the mud and the nature of what's below.
- tuatoru 2y ago
  * piqued
  - GeorgeTirebiter 2y ago
    yes, piqued. English, so weird! ;-) (Although, interest peaking is possible!)
    - speed_spread 2y ago
      > English, so weird Borrowed from just-as-weird French "piquer" - to stab or jab.
      - teleforce 2y ago
        As other more than 30% of English words [1]: [1] Is English just badly pronounced French [video]: https://news.ycombinator.com/item?id=40495393 https://news.ycombinator.com/item?id=40495393
        funnybeam 2y ago
        No, French is badly pronounced French - the English (Norman) versions are often closer to the original pronunciation
        inanutshellus 2y ago
        All this reminds me of the now-famous quote about English "borrowing" words... > The problem with defending the purity of the English language is that English is about as pure as a cribhouse whore. We don't just borrow words; on occasion, English has pursued other languages down alleyways to beat them unconscious and rifle their pockets for new vocabulary. (quote swiped from https://en.wikiquote.org/wiki/James_Nicoll https://en.wikiquote.org/wiki/James_Nicoll)
      - bee_rider 2y ago
        It is kind of funny that both of the incorrect versions, peaked or peeked, sort of make more sense just based on the definitions of the individual words. “Peaked my interest” in particular could be interpreted as “reached the top of my interest.” Way better than stabbing my interest, in a French fashion or otherwise.
6451937099 2y ago
[dead]
qdot76367 2y ago
Ah, it's good to see you continuing your work with types of robots that start with f.
- TaylorAlexander 2y ago
  Hah thats right. I did get some parts to try to update the other one you are referring to, but given all my projects it has not made it near the top of the queue yet.
roshankhan28 2y ago
i am not a engineer type of person but to even thing that someone is trying to create a motor is really impressive. When i was a kid , i used t break my toy cars and would get motors from it and felt like i really did something. good ol' days.
- throwaway81523 2y ago
  The motor controller is impressive, but it sounds like a motor controller (as it says), rather than a motor. That is, it's not mechanical, it's electrical, it sends inputs to the motor telling it when to turn the individual magnets on and off. That is a nontrivial challenge since it has to monitor the motor speeds under varying loads and send pulses at exactly the right time, but it's software and electronics, not machinery.
Rinzler89 2y ago
>I have been developing a brushless motor driver based on the RP2040 Can I ask why? There's dedicated MCU for BLDC motor control out there that have the dedicated peripherals to get the best and easiest sensored/sensorless BLDC motor control plus the supporting application notes and code samples. The RP2040 is not equipped to be good at this task.
- SequoiaHope 2y ago
  > dedicated MCU for BLDC motor control During the chip shortage, specialized chips like this were very hard to find. Meanwhile the RP2040 was the highest stocked MCU at digikey and most other places that carried it. The farm robot drive motors don't need high speed control loops or anything. We just needed a low cost flexible system we could have fabbed at JLCPCB. The RP2040 also has very nice documentation and in general is just very lovely to work with. Also SimpleFOC was already ported to the RP2040, so we had example code etc too. Honestly the CPU was the easy part. As we expected, getting a solid mosfet bridge design was the challenging part.
technofiend 2y ago
Taylor, wow! I think you're the only person I've actually seen implement WAAS to boost GPS precision. So cool!

sgu999 2y ago

> for our farm robot That peaked my interest, here's the video for those who want to save a few clicks: https://www.youtube.com/watch?v=fFhTPHlPAAk https://www.youtube.com/watch?v=fFhTPHlPAAk I absolutely love that they use bike parts for the feet and wheels.

HeyLaughingBoy 2y ago
I have given some thought to a two-wheeled electric tractor for dealing with mud -- horse paddocks turn into basically a 1-foot deep slurry after heavy rain and it can be easier to deal with something small that sinks through the mud, down to solid ground than something using large floatation tires. Additional problem with large tires is that they tend to throw mud around, making everyone nearby even more dirty. I haven't actually built anything (been paying attention to Taylor's work, though), but I came to the same conclusion that bike wheels & tires would probably be a good choice. It also doesn't hurt that we have many discarded kids' bikes all over the place.
- littlestymaar 2y ago
  Your description fit what I've seen for rice farming, whose machines usually use bike-like tires.
  - vintagedave 2y ago
    I’m curious there. I’ve seen rice paddies plowed in Vietnam and the tractors used wide paddle-like wheels. I saw two varieties: one with what looked like more normal wheels but much wider, and one which was of metal with fins, very much akin to a paddle steamer, though still with some kind of flat surface that must have distributed weight. Would they be more effective with thin wheels? Both humans and cattle seem to sink in a few inches and stop; I don’t know what’s under the layer of mud and what makes up a rice paddy.
    - littlestymaar 2y ago
      What I saw was in Taiwan, but I guess it must depends on the depth of the mud and the nature of what's below.
tuatoru 2y ago
* piqued
- GeorgeTirebiter 2y ago
  yes, piqued. English, so weird! ;-) (Although, interest peaking is possible!)
  - speed_spread 2y ago
    > English, so weird Borrowed from just-as-weird French "piquer" - to stab or jab.
    - teleforce 2y ago
      As other more than 30% of English words [1]: [1] Is English just badly pronounced French [video]: https://news.ycombinator.com/item?id=40495393 https://news.ycombinator.com/item?id=40495393
      - funnybeam 2y ago
        No, French is badly pronounced French - the English (Norman) versions are often closer to the original pronunciation
        inanutshellus 2y ago
        All this reminds me of the now-famous quote about English "borrowing" words... > The problem with defending the purity of the English language is that English is about as pure as a cribhouse whore. We don't just borrow words; on occasion, English has pursued other languages down alleyways to beat them unconscious and rifle their pockets for new vocabulary. (quote swiped from https://en.wikiquote.org/wiki/James_Nicoll https://en.wikiquote.org/wiki/James_Nicoll)
    - bee_rider 2y ago
      It is kind of funny that both of the incorrect versions, peaked or peeked, sort of make more sense just based on the definitions of the individual words. “Peaked my interest” in particular could be interpreted as “reached the top of my interest.” Way better than stabbing my interest, in a French fashion or otherwise.

6451937099 2y ago

[dead]

qdot76367 2y ago

Ah, it's good to see you continuing your work with types of robots that start with f.

TaylorAlexander 2y ago
Hah thats right. I did get some parts to try to update the other one you are referring to, but given all my projects it has not made it near the top of the queue yet.

roshankhan28 2y ago

i am not a engineer type of person but to even thing that someone is trying to create a motor is really impressive. When i was a kid , i used t break my toy cars and would get motors from it and felt like i really did something. good ol' days.

throwaway81523 2y ago
The motor controller is impressive, but it sounds like a motor controller (as it says), rather than a motor. That is, it's not mechanical, it's electrical, it sends inputs to the motor telling it when to turn the individual magnets on and off. That is a nontrivial challenge since it has to monitor the motor speeds under varying loads and send pulses at exactly the right time, but it's software and electronics, not machinery.

Rinzler89 2y ago

>I have been developing a brushless motor driver based on the RP2040 Can I ask why? There's dedicated MCU for BLDC motor control out there that have the dedicated peripherals to get the best and easiest sensored/sensorless BLDC motor control plus the supporting application notes and code samples. The RP2040 is not equipped to be good at this task.

SequoiaHope 2y ago
> dedicated MCU for BLDC motor control During the chip shortage, specialized chips like this were very hard to find. Meanwhile the RP2040 was the highest stocked MCU at digikey and most other places that carried it. The farm robot drive motors don't need high speed control loops or anything. We just needed a low cost flexible system we could have fabbed at JLCPCB. The RP2040 also has very nice documentation and in general is just very lovely to work with. Also SimpleFOC was already ported to the RP2040, so we had example code etc too. Honestly the CPU was the easy part. As we expected, getting a solid mosfet bridge design was the challenging part.

technofiend 2y ago

Taylor, wow! I think you're the only person I've actually seen implement WAAS to boost GPS precision. So cool!