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I was having a fun discussion with google AI about trying to build a 4WD 4WS gps guided lawnmower. The idea is to build a chassis with 4 "slew drive units" (SDUs), one on each corner. The SDU would consist of a drive wheel and a vertical rotation axis capable of +- 180 degrees. I currently have a very basic RC lawnmower I built. The only thing I don't like is doing 180s with it, it is only 2WD, but if you're not careful with it, it does dig into the lawn. It's "skid steer", no turing steering, just casters.

So my new concept with the 4 SDUs would have 2 distinct drive modes:

1. conventional curve follow mode. this would pretty much act like a 4WD platform and it would use front and rear steering to gently follow medium size curves up to straight lines. The "body" of the platform would align with the direction of motion following the curve. Say during a mild left curve the front 2 SDUs would turn a bit left and the rear 2 SDUs would turn a bit right to allow a nice following of the curve and keep the platform aligned with the direction of motion.

2. transition to next "parallel" row. this would be kind of like a zig pattern in machining. The idea is to transition at the end of one row to the beginning of the next row without any tight turns or reversing wheels spinning on the grass. If the machine is moving say, directly East and it arrives at the end of it's row, the main platform is pointed East and will maintain that Eastward direction as the 4 SDUs "slew" each steering unit through a 180 degree rotation that drives it to the next row, say to the South, all 4 SDUs would turn say 30 degrees to the right and keep driving "forward". During this transition, "forward" eventually become directly to the West (after each SDU has completed a 180 degree arc), but the platform body is still facing East. Each SDU will follow a "perfect" 180 degree equi-radius path bringing the still-facing-East-platform to the next row. The exact opposite of this would happen at the end of the West running row (and untangling the SDUs wires) to bring everything back to normal at the beginning of the next East facing row.

So Ardupilot is a system used for RC airplanes and drones and such that allows GPS guided "missions". By using RTK GPS you can get cm level accuracy. The software already has a "rover" version that can do conventional mowing patterns but it can't do the kind of motion I'd like to try.

So I asked AI if Linuxcnc could help with this. Of course it said, "That is some next level genius engineering solution, just let HAL take care of it for you."  And I said "can you just make that happen for me?"

At this point it's just a thought exercise, but if you understand what I'm trying to do, could you give me advice as to how I should learn how HAL works? I run Linuxcnc on my DIY 3 Axis router, so I'm familiar with that, but not HAL.

I'm imagining loading a lawnmower path g-code into LinuxCNC and it would use 8 Axii (4 drive motors and four rotational axii for steering). Maybe it could use custom M-codes to specify which mode it's running in (curve follow or slew mode row transition). Somehow we would need to get GPS feedback into LinuxCNC to correct for slip. There would actually be two GPSs on the platform to provide a heading instead of the unreliable magnetic compass. I think I would just use the Ardupilot Mission Planner to read the GPSs and somehow that needs to get to LinuxCNC for feedback.

I'm imagining the code would all be G1 moves and for the tight turns at the end, simply allow the path look ahead to decelerate the drives and accelerate the steering as setup on each axis physical limits.

I'll try to draw up some diagrams if the turning strategy is confusing as I'm not sure I explained it right.

I have an LS486, but I can't find any information about the signal pinout of the connector.

The problem is that I don't have the original cable, and the replacement cable is quite expensive.

Does anyone have the pinout or wiring information for the connector, or perhaps a diagram showing which signals correspond to each pin?

Any help would be greatly appreciated.

Thank you!

 

Todd, have a look here
forum.linuxcnc.org/38-general-linuxcnc-q...or-consultant#349473
And let me know when done so i can delete this.
Thank you.

Hi Cofhal,

Thank you for your purchase.

1) Full 3D Toolpaths - Adaptive Clear, Pocket Clear, Z Level Finish, Parallel / Raster Finish dont get surfaced by Feature Recognition. They are for whole part or selection by face or chains.

2) After Feature Recognition is done, you can hover over each feature and it lights up on the model. You can keep the model semitransparent to better view buried features like holes.

I will create a detailed thread on our community forum where you have already signed up in case you need more details.

What is the best way to contact Todd. Sorry I am new to the forum.

Email me at This email address is being protected from spambots. You need JavaScript enabled to view it. and we can take it from there.

I have some electronic diagrams for that one; they might be useful to you.
www.illianaindtech.com/PartsBook3-14-14/...00guid.htm#ALostSink
Try talking to Jerry at JB cnc repair in New York. He knows the controls very well. Since most anilam controls were a retrofit he may have an idea where to find you more info.

gbouvier2.wixsite.com/website/anilam-parts-book

Been following on that occasionally, glad to know something is being done to fix that.
Thank you.

Holzwurm56 wrote:

I’d like to try LCNC again on a different PC. Is there perhaps a mini live ISO with a real-time kernel—available on a USB stick or DVD—that contains only the latency test? That way, I could test the PCs beforehand rather than wiping everything, installing LCNC, and then finding out it doesn't work. Thanks,
Hans

You can do all that with the official ISO.

I’ve purchased the license and am testing the program, but I have one remaining question. When automatically generating machining tasks, I noticed that it doesn't detect any 3D tasks. Another issue is that, upon generating these tasks, they cannot be viewed on the model until the toolpath itself is generated; sometimes, it’s hard to tell which machining task was created, making it difficult to select the right tool.

Thank You !

Yes, the installer is also a live system so run it up, select live and run your tests  It won't save any settings between sessions so I just  usually install Linux and test on the PC itself.

If your spindle is on a VFD, you can save 4 pins by using mb2hal and Modbus RTU from a serial port (forward,reverse, PWM, at speed). By using HOME_SEQUENCE you can reduce the number of inputs required by sharing a single pin for homing. You also gain torque feedback, a more noise resilient system and much more accurate spindle speeds. You don't loose anything. People mistakenly think you need 0-10v spindle control for rigid tapping. But that's not right. In LinuxCNC spindle control is not real time and with rigid tapping, Z axis motion is synchronized by the spindle encoder.
But for the sake of a couple of weeks, why not wait for a mesa card?

tommylight wrote:

tuxcnc wrote:

"Ethercat is faster" is not a valid argument,...

He did not say "faster", he said more efficient, and even that does not seem correct to me from what i read around here, no experience with ethercat yet except rare services of machines using them.
I am intentionally refusing to use ethercat until something is done to have proper feedback, so far it does not work or it does work with big delays.
But, i would really like to have the redundancy it may offer, for now only in showrooms.

I think you are out of date Tommy. Grandixximo has done a lot of work and maintains an improved version of Ethercat specifically for LinuxCNC and also ahs done changes to the core code in LinuxCNC that improves how the Ethercat thread and servo thread sync on startup. Drive feedback form the encoder is just another variable on the Ethercat bus.The included lcec-configgen will build the xml file for you.

The system I use is a Compaq Presario Desktop having 3.3 GB memory, AMD Athelon 64X2 dual core processor 4200+ x2. 
Linux 12.04 setup says 32 bit os.  Its 196 GB hard disk currently setup with the rtai kernel booting on one partition  and Ubuntu 24.04 LTS booting on the other partition.  There's about 80 GB left on either partition.  The mill I have is a Taig 4019 3 Axis  and a cnc rotary table, so its a 4 axis machine.  The mill controller board is a xylotex XS3525/8S-4  which supports 4 stepper motors.  The Taig mill has no sensers and neither does the rotary table so testing feed synchronization isn't (as in tapping) easy.  As far as updating is concerned I'd liketo replace the 24.04 LTS with a linux cnc kernel that still supports my mill but don't know if one is available and the rtai kernel continues to work so the only thing wrong is interrnet access, I keep the net shut of when running the mill with the rtai kernel anyway.  The system is cabled through a router that's supposed to be 100MB/sec.  I don't know how much disk space may be needed if we're rebuilding kernels or Axis from source code, hopefully 80GB might be enough  Also I don't have a lot of code ready to test the synch between linear motion and the cnc rotary table which I mostly use for sharpening endmills. If testing the rtai driver means sending some code to be installed on the rtai partition, I can do that too, the 24.04 LTS machine can read and write in the rtai partition but the rtai os doesn't understand the format of the 24 partition.