Hi, xacro is a macro format for generating urdf's on the fly. You can do that in the terminal as well, you'll find samples online, here's one https://automaticaddison.com/how-to-convert-a-xacro-file-to-urdf-and-then-to-sdf/

For anyone interested, here's what the newest velocity control implementation might look like in practice. It allows for over 10 times faster acceleration amd velocity than the original position based control, while maintaining smaller position and goal errors. @ycheng517 is merging these new changes into his solution, see https://www.anninrobotics.com/forum/general-discussion/ros-2-driver-for-ar4-now-available WhatsApp Video 2024-12-03 at 10.09.51.mp4 (Original trajectory and goal limits are 0.02)

No changes necessary, as long as the switches give the same output as the original - some work in reverse.

Hi, here's a few pictures of the limit switches on linear track and J2.

Hi, been traveling so I haven't had a chance to get the pictures yet, but haven't forgotten. Well, I've only replaced a few so far, but with the optical switches the linear track is astoundingly accurate, zero-point is more accurate than 0.1 mm. I think the main performance issue is play in the gears/motors, but for starting positions these do really help.

Hi! I bought a bunch of these and some with alternative rotations https://www.aliexpress.com/item/1005004869889677.html you could just drop them in place (same wiring), but you need to 3d-print or otherwise create some blocks to keep them nicely in place. J2 and the linear track are the easiest, for the others I haven't made reliable solutions yet. I can post closer pictures of these.

Hi all, brief update. I have done work on the ROS2 solution to include a linear track, Pilz Motion Planner and velocity control (instead of the original position control) for a huge increase in speed while maintaining tolerances, among many other things. I replaced some of the limit switches with optical switches, added a voltage and amperage display and incorporated a panic button in the code. WhatsApp Video 2024-10-22 at 14.27.19.mp4 WhatsApp Video 2024-10-22 at 14.27.30.mp4 I'm using PlotJuggler in testing to validate the velocities, positions and accelerations, it's very helpful.

Hi, this actually happens to me too. :/ lifting the cables higher up on the arm helped, but they still sometimes get pinched

Thanks, super much appreciated. You're right, the price difference is big and changing the motor for the linear track later on is easy (compared to changing say a motor of the arm). Your build look very neat and professional, hopefully I'll manage to pull off something similar. :D Now learning to work with ros 2 and build some c++ for control.

Beautiful! Thank you for the update. How does the linear track look like in action? I see you've got a beautiful cable chain, printed or purchased? :) What motor did you go for for the linear track, I wonder if I should get one with an encoder or not. :o

This is really cool! Any video of this in action?

I have tested this with the MK3, looks very promising and works. We are still working with @ycheng517 on calibration details, my joints are a little off.

Small caps helped me as well!

Hi! Since you can tell it's too loud for your taste, I assume you've got the AR up and running? How about measuring the actual temperatures during high load? Then you could slow down the fan and see how that changes. You could do this either by lowering the voltage by a constant (say, with a zener), or making it adjustable (voltage divider and potentiometer). Or if you want to make it fancy do, pwm with an attiny or the teensy - you could adjust speed based on temperatures.

..but as Richard mentioned, when you actually read the manual and watch which way the housing goes on the screw, only the very tip needs to be filed. :)

Hi, I seem to have the same issue, disappointed with stepperonline. The entire screw is 8.1-8.2 mm thick. Have to go filing something like half the screw as well..

From what I've read online it should be safe for the steppers (and drivers) to move them by hand slowly. Moving fast could potentially generate a voltage that would damage some part of the circuit connected to the motors.

Nothing to hammer, shaft moves quite easily into the slot and motor bottoms out in the spacer.

Thanks for your quick responses, guys! Spacer seems to be 10.75mm, and after making sure the motor is fully seated in the spacer there's still 13.3mm of the housing sticking out. I will sandpaper the spacer a fraction of a mm and then we should be very close (within half a mm) to the correct values. How crucial is it that the gap between the J2 gearbox motor housing and the J2 tension ring is 1 and not say 2 or 3 mm?

I purchased mine just a few weeks ago, and the screws really were quite tight. I got them all off by carefully using an impact driver.