Hi,
Me and my advisor are looking to build a solo12. We’re exploring the possibility of using the TI Evaluation boards instead of the custom BLMC μDriver.
What extra work would be involved in getting the robot up and running? Can they be flashed with the same drivers, and are they electronically interchangeable? We are doing this for cost and and also reusability concerns. We are aware that 6 evaluation boards won’t fit, but we think we are able to create our own mounts, unless we are overlooking some limitation.
Will this be difficult? Would you advice against it?
Hi,
yes - that’s possible.
The robot will be bulkier, about 500g heavier and you will need 6 CAN connections and 3 dual channel can cards to run the robot. The can-to-pci cards are quite expensive - so I am not sure how much money you’ll save.
The main difficulty is probably to redesign the body structure and to make enough space for the electronics. You can for example remove the bottom pin headers on the booster packs to save some space.
We using the Masterboard and the Micro Driver electronics - and we are working on enhancements that you won’t be able to use with the TI eval boards.
With the new electronics we are now able to run the PD+ controllers at 10kHz on the micro driver cards. With the Masterboard we can control up to 16 motors and transmit IMU data at 1kHz via a single Ethernet wire. We are also working on the wireless communication and the onboard battery integration.
The TI boards cannot be flashed wit the same drivers. (we repurposed an SPI channel to communicate with the master board)
The drivers for using the TI boards can be found here:
Best. Felix
Hello again,
Whats the reason we need 3 dual channel CAN cards? Are suggesting we need to connect the channels 1-1 with the TI cards? To me it seemed like you used one can card for the solo8, but I could of course be mistaken there.
CAN uses broadcast messages, so why the 1-1 connections? Is this a bandwidth issue, or is this due to ease of implementation?
Could we buy one 1 dual channel and 1 four channel card?
We are probably gonna buy the replacement for the one listed on GitHub, as that one has gone out of production.
I was a bit mistaken when I first posted this question, our main problem with the custom boards isn’t cost, but availability and ease of getting a replacement, if that would be needed:)
It seems my questions were recently answered here, so I would look there TriFinger Build Questions
Hello,
for Solo8 v1 we are using two dual-channel CAN cards to control the 8 degrees of freedom.
In the beginning we were using a 3 axis force sensor at the foot that was also communicating via CAN.
With that sensor on the same CAN bus there was no more bandwidth available.
@felixwidmaier would know better if it’s now possible to combine two cards on one channel and what changes to the firmware would be required.
Thanks for letting us know that the PCAN-PCI Express cards are now longer available.
The FD version should be backwards compatible - but we haven’t tested those cards.
From what I recall we are using almost the full bandwidth with one card to be able to run at 1 kHz, so two cards on the same CAN bus would not work.
It would probably be possible if you reduce the control rate but this would require some bigger change in the firmware as the messages of the two boards would need to be distinguished somehow.
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