Robot dog can kill weeds by blowing them away with a burner

Robot dogs equipped with burners could be used to prevent weeds from growing on farms, offering a potential alternative to harmful herbicides.

Even highly targeted herbicides can cause environmental problems and affect local wildlife, and “superweeds” are rapidly evolving resistance to the most common herbicides like glyphosate.

Searching for an alternative solution, Dezhen Song of Texas A&M University and his colleagues developed a weed-control system that uses short bursts of heat from a propane-powered torch controlled by a robotic arm attached to a Boston Dynamics Spot robot.

Rather than incinerating weeds, the robot is designed to identify and heat the core of the plant, which can stop weed growth for weeks, Song said. “It doesn’t kill the weeds, it just inhibits their growth, giving the crop a chance to fight them.”

Song and his team first tested the flame nozzle to see if it could accurately target the center of the weeds, then deployed the robot in a cotton field that was also planted with weeds, including sunflowers, which are native to Texas.Sun Flower) and giant ragweed (Ambrosia trifidaFive tests showed the robot could find weeds and focus an average of 95 percent of its flames on them to burn them down.

One of the Spot robot’s major limitations is its battery life — in this setup it can only operate for about 40 minutes before needing to be recharged — but the team is working on upgrading it to a longer-lasting device, Song said. They’re also considering equipping the robot dog with an electric shock device that can deliver more than 10,000 volts of current, which would allow it to stop weeds from growing for longer.

“Other machines have used fairly broad, imprecise flames to kill weeds. This has been done for a while, but I’ve never seen anything this precise,” says Simon Pearson of the University of Lincoln in the U.K. The robot’s success will depend on how precisely it can cast the flames and avoid damaging valuable crops, he says.