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Did you consider using an actuator with feed back for steering? It would make life so much easier than trying to mount a wheel angle sensor.
 

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Discussion Starter #23
Yeah I did try to get an actuator with feedback but the only one I could find in the UK was way too slow. Also the relationship between the stroke length and the angle is not linear (not sure how to explain this without pictures) thinking on it again I don't think it would have been as big of a problem as I initially thought. Now I know the length of ram I need and the rough speed I need I might try and order one from AliExpress with feedback.
 

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No need for pictures, I know what you mean. To keep things linear is just a matter of keeping the distances of the ends of the actuator equal and adjusting those distances to get the speed you need. I have a couple of FB actuators, all slow although not much difference between non FB actuators. The one plus(or negative) is you are doing a rear steer. Generally you do not need as much travel on the steer compared to front steer so a slow actuator would be to your benefit. If you want a good supplier from Aliexpess, pm me. I don't like advertising or endorsing particular suppliers in case something goes wrong.
 

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Discussion Starter #26
The feedback actuator was my original idea, it may be time soon to switch back to the idea as I am making things more complicated than they need to be. I have bought a string potentiometer to play around with so I might need to persevere until I can bring myself to spend more money on this project.
 

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Discussion Starter #27 (Edited)
The feedback actuator was my original idea, it may be time soon to switch back to the idea as I am making things more complicated than they need to be. I have bought a string potentiometer to play around with so I might need to persevere until I can bring myself to spend more money on the project.

The main reasons I went against the FB actuator was the lack of choice in speed and stroke length. Also that the linear actuators do not seem to follow the arc of the steering. 1mm of movement depending on the position of the actuator does not always = the same amount of degrees of travel round the arc. The string pot solved this by pulling the string round a circular pulley on the steering.
 

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Keep it simple. I have plenty of experience of making things way to complicated. Stop over thinking things as I think you are on the right track :).
 

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Discussion Starter #29
Thanks Beerwise. You are definitely right. Please send me the link to the feedback actuator source that you recommend. Many thanks Gav
 

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Discussion Starter #30 (Edited)
A small test in the field. Seems to have a decent amount of power for a 200w motor running at half its rated voltage. Plenty of traction as I load up the front Axel by sitting on the machine you can see the back wheel still has grip to push me along. You can see the belt now has a sprung tensioner helping to wrap the belt more around the pulley really helps to prevent the belt skipping teeth.

 

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Needs a seat, for testing purposes of course:D. It just looks fun to ride on. I may have to build one for doing lawns once they are mapped.
 

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Discussion Starter #34
Thanks guys, finding time for projects is probably the biggest barrier to getting this stuff built.

Mk2 should definitely come with a seat.. or a Hammock!
 

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Discussion Starter #35
Finally got a chance to wire up the self steer and have my first play around with agopengps

Great bit of software!

I found that when I switch to rear wheel steering it makes a turn in the wrong direction and then loses control and makes its way across the field at 90 degrees to the ab lines. Does the rear wheel steer function work at the moment. The video shows it working well in front steer mode but obviously back to front. Thanks

 

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Discussion Starter #38
Does the simulator inside Agopengps also simulate the Arduino ie steering angle feedback. Could this be the reason the rear steer does not function correctly in simulation mode?
 

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Does the simulator inside Agopengps also simulate the Arduino ie steering angle feedback. Could this be the reason the rear steer does not function correctly in simulation mode?

The simulator works just inside AOG, it won't talk to the arduino at all properly or do anything with the information that comes back. The simulator, when set up a rear steer vehicle does work correctly.
 

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Discussion Starter #40
Docknet v1. I trained a neural network to identify broadleaved docks in grass backgrounds/fields.

https://www.thecombineforum.com/forums/attachment.php?attachmentid=149877&thumb=1

A python loop chops the original image into squares of 256 x 256 pixels, a neural network identifies if the image square contains a dock or not dock. Python then inverts the image block colours if it see a dock. The squares are then stitched back together to form the output. The inverted blocks stand out so we can see where the weeds are. A toy example that shows the effectiveness of neural network for weed identification.
 

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