We have robot arm itself (e.g. Ur5) without controller. Not yet actually, but let`s imagine.
We have our own industrial computer with closed loop feedback from some imaginary production process. Conmputer with almost any I/O possible - rs, can, eth, di, do, etc. Where our custom software deployed which is generating control commands for the robot (move there, pick that in non-linear series based on feedback). ROS or some direct drive commands not sure yet.
This production process has only 24v available voltage supply so we will arrange our own power supply box with 48V boost converter of sufficient power output and all protections nessesary.
So we have an arm, custom PC, custom power supply.
Connecting supply voltage looks straighforward. But what about custom PC(controller) conenction. Is it possible to control robot directly from non genuine hardware?
What do we need? RS485 protocols descriptions (are they available for general public or at least UR customers?) Wiring diagrams? ROS?
Is it even possible? Where to start?
All replies is much appreciated. Thanks in advance. Alex.
Safety protocols are implemented on UR controller, and joint drives. Controller or arm can not be used safely on it’s own.
On top of that UR invested millions in software for these components. It would be unwise not to use it.
Yes i understand that and agree to some extent, but how can we get full RS485 protocol description for joint drives? Are they disclosed or this is total no go?
I know that this experiments might and will void warranty. But i can gurantee tho that all safety requirements will be present and if this approach fails miserably we will come back to regular programming.
if space is a concern you can go with the OEM control boxes without pendant which are much more compact and directly powered by DC supplies, and if you want to bypass the motion planner you can use servoj/speedj commands with your own control loops, or through the ROS driver directly.
I understand the interest as I myself wondered if that was even possible, but it likely will be an immense rabbit hole of trying to recreate what you already have in hand? Or what is the purpose of ditching the controller?
Can someone provide a link to documentation about the UR5 Controller? It would be good to read up on what exactly is provided and what is not. I assume it must be closed loop and I l read somewhere that it does the Inverse kinematics but I would like to know in detail.
as far as i know there is no documentation of the low level protocol on the rs-485 bus between controller and robot joints, you could try reverse engineering it but you’d also need to reverse engineer everything going in the firmware of each joints since they are all independently running unlike “simple” servos with encoders on typical robots with servo drives in the controller. You can easily find the ur user manual and programming references but there’s nothing very deep regarding low level hardware.
