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Fully Autonomous Weedings

A project log for WEEDINATOR 2019

The WEEDINATOR project continues .... The inevitability of robots working on farms draws ever nearer ....

capt-flatus-oflahertyCapt. Flatus O'Flaherty ☠ 07/21/2018 at 17:220 Comments

Finally ……. After one whole year of work ….. We have autonomous weeding. Actually the machine can now navigate through a series of waypoints using super accurate error correcting 'RTK' GPS and, additionally, it can now navigate along a bed of seedlings and weed the bed with a rotating claw to an accuracy of about +- 5mm. Navigation on the bed itself uses a line following camera - the Pixy2 as even the very best GPS can't navigate to the accuracy that we need to avoid killing the plants.

The CNC claw is programmed to move in the pattern shown above, weeding two rows of seedlings every time the machine stops. Some of the code can be seen in the previous log. When the claw reaches position 15, the whole machine moves slowly forwards with the claw still weeding, following a white rope, until it reaches a barcode. Then, when the Pixy2 sees the barcode move to a certain point in the it's field of view, it stops the machine dead and tells the CNC to do another circuit. Full details of the code can be seen here.

So what's next? This certainly is not the end of the project as, apart from anything else, there are a few annoying bugs to fix and the drive motors used are either not set up correctly or simply not appropriate ….. If only I could bypass the positioning feature of the motor drivers when the machine is driving up paths etc. …… They're great on the beds of seedlings though.

In terms of the mechanics of the machine, the next stage would be to start thinking about performing another task such as planting. This is actually probably more challenging than weeding, although sowing seeds would be easy enough. Seedlings are a different matter as they are in plugs of compost with roots and stems. The CNC mechanism can perform planting seedlings with the weeding claw apparatus swapped out for a different device ….. Who knows what that will look like?

In reality, there's quite a bit of work to do on the control system. The original aim of the project was to try and use advanced Ai based object detection to help with navigation and this now seems to be very much more realistic. Now that the vegetable season here has pretty much finished, the main focus of the project has switched to working on the Jetson TX2 Ai platform to enable plant recognition.

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