I am currently in the process of putting together a design to run the UR20 robot arm with a 48V LiFePo battery being the power source. My intent is to use a DC/DC supply to get a consistent voltage and load.
Does anyone have an experience with running in a configuration as such? On one hand, I would like to source something that can handle absolutes for the robot, which mean getting 1500W power supply. Given the other electronics we need to support, that’s looking at close to 2000W. While possible, it will be difficult in the space constraint I have to work with.
Alternatively, I know that I’m not using that much power. I know that during our use case the UR20, according to the debug menu, is not pulling any more than 100W. I know there will be a higher peak to worry about during initial power up.
So my question is, has anyone ran the UR20 off of DC/DC supplies and if so which ones? And alternatively, has anyone ran the UR20 off of a smaller wattage supply and is there any additional workaround to ensure the power draw is sufficient? I found a (possibly outdated) document that talks about modifying the urcontrol.conf file and changing the “power_supply” parameter. However I’ve not been able to find anything else regarding what exactly that accomplishes.
I hope that explains things. Help would be greatly appreciated.
The biggest power draw is definitely acceleration of the robot arm, as you mention yourself. So running the robot at a slow pace will draw less current.
But it is a matter of testing, I believe. I wouldn’t trust the reading on the debug menu too much, though.
Adjusting the “power_supply” property in the /root/.urcontrol/urcontrol.conf will let “URControl”(the process that is managing the motion control of the arm) be aware of the limited power. And will limit acceleration based on the power limit and the dynamics of the robot. The readings in the log menu is a good indicator but as @efn mention you might miss spikes that are short in time.
You might leave a little headroom, for the consumption of the Control box itself and to avoid too much struggle😉
We would be happy to see a video, when you have it running🙏
I think my best option is going to be sourcing the largest power supply I can fit with my space constraints but I will also utilize that modification of the power_supply property.
@Ebbe do you happen to know of some documentation, such as a developers guide, that goes over the parameters of these config files?
This is one of the implicit APIs that is not intended for use. But also give you the freedom to limit the robots power consumption. There is limited public documentation.
So unless you have any specific needs, I would recommend not to touch the rest of it😉
