I am looking at doing some leveling of my own land. A one-time project. Looking at OpenGrade3D I don’t see tandem support - am I right?
I presume to add it I would need to modify the application to add a second NMEA input from a second rover over the back blade and then add support to control the valve? Am I overlooking anything?
I am currently not sure which way to go, whether to do this or buy an FMX unit with Field Level II. I am confident I can modify the software to add support for tandem scrapers but I would then have to debug it and I live 1,200 miles from my land, so that is a bit of an issue.
So first, I don’t really know about Field Level II but OG3D work with a design map you create from a third party software like Optisurface, the import file is .agd
So, what OG3D mostly do: it simply output the delta between real and target altitude.
You could also run 2 completely separate systems, one for each scraper. (I understand that tandem is one behind the other?)
Limitations right now:
OG3D use one USB for the receiver right now so in your setup that means longs cables somehow.
And a second USB port for machine control.
I have one branch on GitHub that use UDP and AgIO but it’s highly experimental. I just copy pasted things from AOG without reading really know what I was doing.
This version still control the machine through USB and can’t run other AOG software besides (socket problem if someone understand that )
Machine control:
You want to use the JD/Case analog SCV feature or add proportional valves?
One advantage from OG3D: if you have internet in the tractor you can connect and debug from distance via remote desktop or wireshark.
I want to completely bypass the tractor, so I presume I need to use the cytron to directly control the proportional valve on each scraper.
For tandem operation when cutting the front scraper fills first and then the rear scraper. Am I understanding correctly that OpenGrade3D does not automatically raise the blade when the scraper is full? I.e. how would it know the scraper is full? I’m not sure commercial systems even do this.
I have loaded my ags file into OpenGrade3D but I am not sure how to simulate the cutting operation. I see the yellow representation of the blade but it just cuts at whatever height I set it. How do I simulate the automatic blade height control? Do I need an Arduino hooked up with the ino file running to see that work?
You have to change the antenna height in simulator.
In real work, lifting/lowering make the antenna height move(of course) then OG calculate next delta for next valve command.
There is quite latency is this. 60ms for the F9P calculation, transfer to tablet, OG calculation, transfer to machine module.
The antenna height trigger the valve lifting or lowering.
I have a proportional lever on my machine ino.
In automatic mode I can lower the blade, auto then enable.
As soon as I lift, auto disable.
Unless you install something to monitor the filling, the operator must lower to start filling and lift at the end.
I am trying to visualize how this works. Suppose I have a 0.5m hill that I need to remove. Obviously that can’t be done in one pass, so how does the OG blade follow the profile of the hill on the first pass? Does it remove just the top or does it follow the profile of the hill removing a consistent amount?
Then as you approach the proposed elevation it starts to automatically remove less and less?
Sadly the operator must manually lift and control the filling until it can cut to the final height.
I was thinking it could be cool to read the tractor slippage and power usage (over CANBUS) to automatically lift the blade. But that’s far on the enhancement list!
A maximum cut feature could indeed be cool. But for now all the actual cut recording stuff is not really usable (I don’t have the coding skills for this). So more or less, OG3D doesn’t really know how much earthwork actually has been moved.
Suppose at a specific location the existing height is 2m and the proposed height (from OptiSurface) is 1.5m. The cut/fill is therefore -0.5m.
OG is getting RTK corrected NMEA data. The GPS antenna is on the scraper over the blade.
What does OG do in regards to the blade height as it approaches this location?
Does it drop the blade to 1.5m to try and remove everything in one go? If not, what will it drop the blade to?
I do have the programming skills to work on this, but first I am trying to understand the current capabilities and see how far off it is from what I need.
Thanks Pat. My understanding (having never done any leveling) is that if you try to remove more than 0.2 ft at a time the scraper will bog down.
So, as far as you know, OG3D hasn’t been used so far on a hilly field? Because I am not seeing how it would work, unless I am misunderstanding something.
Please understand, I am not critizing, just trying to evaluate if I should jump in and start working on OG3D or go with a commercial option and resell it after I am done.
The GPS height is the height of the antenna. If the height of the antenna to ground is known then the height of the ground can be easily calculated.
Lets say I have a hill with a 2m survey height and a proposed height of 1.5m. I drive over that point and using the GPS antenna height to calculate the ground height gives 1.3m, then I know I must haved removed 0.2m on previous passes.
So the software doesn’t need to keep track of what was removed it seems.
So all that is needed is when the ground height is still above the proposed height, lower the blade to the max cut depth.
If the ground height is less than the max cut depth above the proposed height then lower the blade to the proposed height.
So the cut/fill map is not used, only the proposed height map.
For tandem operation my understanding is that the front is loaded first and then the rear. It seems to me all that is needed is for both blades to be set to the cutting depth then the front scraper will block the rear scraper.
Then when the front scraper is full that blade is lifted to allow the rear scraper to fill. Perhaps this could be done by watching and pressing a footswitch?
For dumping I believe the rear is unloaded first and then the front. When the front is being slowly unloaded the blade for the rear is lowered to grade the dirt being released from the front. I guess this can be done manually. Perhaps it always is done manually? I am not sure.
I guess this means there needs to be a max fill height parameter, so in the fill areas the blade doesn’t go higher than specified to grade the output?
Those are just variant of the same data. proposed map is the target height (which is used for calculation). Cut/Fill is the visual so the operator know where to cut and fill.
One thing you should also note is that OG3D doesn’t compensate for roll and tilt so be sure to take the survey points with the same distance from ground (height on vehicle) than the height the antennas will be installed on the scrappers. Especially if you’re on hilly ground.
I think this could be also the case for some commercial systems.
Maybe @kansasfarmer can give some insight about box scrapers and commercial systems.
Two scrapers, each with GPS rover and IMU. Two tablets. One running OpenGrade3D and the other running my custom haul analysis and planning softrware.
The tablets are linked via COM ports so that OpenGrade3D can send info to the second tablet about the scraper states and also the current position, allowing it to dynamically update the cut/fill map and show where I have been already.
Because it is all about the diesel, and therefore time, I am hoping I can replace some leveling experience with software analysis of the hauling routes then put those on a map to give me some guidance.
My plan is to run millions of haul simulations to see if I can brute-force an optimal strategy. I will give my simulator some initial guidance using the haul map from Optisurface.
The buttons will control the manual scraper operations - raising the blades, dumping the dirt, but passing that through the Arduino allows me to report back to OpenGrade3D what is going on.
Blue is user interface.
Green is front scraper
Purple is rear scraper
Orange is a custom circuit board I will design.