During the 2022 World Ag Expo we visited the Carbon Robotics booth to check out the newest LaserWeeder device. The recently released agriculture weeding solution was being shown publicly for the first time during the event.
We were fortunate to interview Alex Sergeev, CTO, Carbon Robotics. He explained how the solution works, described the differences between their two LaserWeeder platforms and gave us a demo of a working laser.
Mobile Robot Guide: Is the LaserWeeder fully autonomous? Can you set it up at the end of a row and just let it go? Can you set a path on Google Maps and outline where you want it to work?
Alex Sergeev: Our autonomous version from last year has an 80 inch, fixed row spacing for the laser weeding operation. It’s basically pre-programmed to drive the fields autonomously.
With this version you make a geo fence field around where you want the robot to operate. It knows autonomously how to navigate rows, once you specify the row spacing you want.
It kills the weeds with lasers, identifying the crop plants using cameras and artificial intelligence. The lasers are invisible and safe for humans, because there are no reflections from the ground.
What crops have you trained/optimized the system to work with?
Sergeev: Basically, we can work with any crop, but we primarily do a lot of specialty crops, and some row crops. If you can see the difference between a crop plant and a weed plant as a human, then the LaserWeeder can also be trained to differentiate the plants.
What really matters is economics. High density crops are where we will have the highest return on investment (ROI).
But we’ve seen a lot of different growers do the math about ROI and how much they spend on weeding. Most farms are looking at an ROI between one and three years.
Okay. So, we’ve done a lot of lettuce, but also onions, carrots, spinach and corn.
We’re not constrained by high density, we actually work very well in high density, because we can do very precision, millimeter accuracy. The crop can be a few millimeters from each other, and it kills the weed and doesn’t kill the crop.
Is there a time in the life of the crop that is ideal to use the LaserWeeder?
Sergeev: The best performance comes if you kill the weeds when they’re the smallest. Typically, what people do very successfully is: they plant, and whenever weeds start to come up, they do a first pass with the LaserWeeder.
It depends on the weather, the field conditions, and the soil. It could be from days to a week or a couple of weeks before the weeds start to show up.
Sometimes they do some pre-application using propane torching before the crop starts coming up, because the crops are not harmed by propane. Then, once your crops grow a little bit and your weeds start to pop up again, you can use LaserWeeder in a very precision surgical application. It also works very well with cultivation, because we can direct energy of the laser in sort of either the whole row or some specific parts of the row. If you do row crops, you can basically mark off in the configuration which areas you want to weed and which areas you will cultivate.
How are farmers deploying the solutions in their operations?
Sergeev: Farmers integrate it very well into their farm operations. Their goal is really to replace the hand crews spraying because even with organic spraying, it actually sets crops back quite a bit whenever you spray.
For example, with an onion crop that’s been sprayed, if you cut open the onion you’ll see some of the onion’s rings are clearly stunted or a different color from the rest of the onion. They were damaged by spraying.
Whereas if you laser weed, all the onion’s rings are exactly the same. They’re all perfect. We’ve validated this with blind A/B tests in the field, spaying some rows and LaserWeeding other rows.
This is crucial for high end restaurants that want to serve perfect onions.
What are the differences between the prior autonomous version and the newest version of the LaserWeeder?
Sergeev: With our previous (autonomous) model, we got feedback from farmers that they want to go bigger. So we built the newest LaserWeeder as a pull behind unit that’s not autonomous, it requires a tractor operator.
The autonomous version is an 80 inch width unit. We got feedback from early customers that different farms have different row spacings. So we designed the pull behind version to be 60 to 84 inch adjustable row spacing.
The new LaserWeeder works like any other implement. It’s capable of covering up to three rows at a time. The row modules are movable. You can shift them around to cover the crop spacing in the rows.
The system takes a lot of energy to operate the lasers and it looks like there are now three times as many lasers in the new implement-version of the LaserWeeder. How do you supply the electrical energy to the implement?
Sergeev: So what we do is we mount a generator in the front of the tractor. We support either a PTO generator, or a front mounted diesel generator. It’s up to the farmer to deploy what best fits their needs.
The current autonomous version has eight lasers, where the new version has 30 lasers. This basically allows each row to have 10 lasers.
Do you think this implement-version of LaserWeeder is likely to be a more popular version of the technology?
Sergeev: At first we’re very open in terms of applications. So we’re really listening to farmers reaching out to us. We do get interest from all over the world, a lot in the U.S., a lot of other countries. We are very interested in what farmers see as good applications.
That will help us decide where to go next. But this new implement version is a very familiar form factor for farmers. They’re not intimidated by the concept of an autonomous tractor. They all have an immediate application because a lot of big farms have a real need for this. Labor is key, and costs are continually going up. Plus farmers love all of the data.
