Morris

COWBOT! Coming to a field near you?

November 2021

By Joel Haskard, photos courtesy of Eric Buchanan

Leave it to the amazing team at the West Central Outreach & Research Center outside of Morris MN to be experimenting with a solar-powered Cowbot.

We asked renewable energy scientist Eric Buchanan to tell us a bit more.

What is Cowbot and what does it do?

The Cowbot is an autonomous mower for weed control in cow pastures. It is a collaboration with researchers in the Computer Science and Engineering department (CSE) and The Toro Company. The Cowbot can come into a pasture after cows have grazed and cut down the weeds the cows didn't eat without cutting the grass. This is especially important in organic pastures where herbicides cannot be used. It uses a flail mower instead of a standard deck mower to better cut large weeds like thistles that are typical in pastures.

The Cowbot is driven around the area to be mowed while an operator logs the GPS coordinates. The onboard controller then calculates the most efficient path to mow that area and returns to a charging trailer when finished.

The Cowbot can come into a pasture after cows have grazed and cut down the weeds the cows didn't eat without cutting the grass. This is especially important in organic pastures where herbicides cannot be used.

Eric Buchanan, renewable energy scientist

How is Cowbot powered?

The Cowbot started life as a diesel powered Toro fairway mower, but was converted to run with an electric motor and to be "drive by wire" which means it can be operated electronically including steering, throttle, and engaging the mower. The battery pack can hold 29 kWh of energy and can be recharged in the pasture with a custom built solar charging trailer. The Cowbot can mow for up to 4 hours before recharging.

Tell us about the trailer? Can you buy these somewhere or do you have to build them yourself?

I have not seen a commercial charging trailer, but I have seen several different versions of custom built trailers. We added 10 solar panels (just over 3 kW) to the roof of an enclosed 17 foot trailer large enough to haul the Cowbot. There are three levels of panels. The top level is fixed, but the bottom two levels slide out on heavy duty drawer slides to collect sunlight. Inside the trailer a charge controller manages the charging of a 48 volt battery pack. The batteries are deep-cycle, solar lead-acid batteries. DC power from the batteries is turned into AC power by a power inverter. The AC power then feeds a few outlets and a level 2 electric car charger which is used to charge the Cowbot, but can also charge electric cars.

So, for now, you will still have to build a charging trailer yourself. The Cowbot itself is still in the research phase so you will get strange looks if you ask your Toro dealer for one.