At up to 400 horsepower, the GridCON from John Deere is a few cable lengths closer to reality in the field. Deere’s autonomous platform relies on plenty of extension cord, not unlike some mining equipment, to get it back and forth in the field.
John Deere says it is plowing ahead to develop electric powered agricultural machinery and has introduced an electric cable-powered tractor delivering up to 400 horsepower.
The GridCON research project and tractor offers farmers the opportunity to supply and use their own energy for field work.
Although John Deere presented its first fully electric tractor, known as the SESAM (Sustainable Energy Supply for Agricultural Machinery), in 2016, this new GridCON tractor looks very different to its predecessor.
The biggest visual differences on the new model are the lack of a cab and no rows of batteries underneath the hood. Still green and yellow, it is the first vehicle to be fully electric, permanently cable-powered and capable of fully autonomous operation in the field.
Based on a John Deere 6210R tractor chassis, GridCON uses a cable connection from a field’s border to the machine, transferring power continuously at more than 300 kilowatts. A 100 kW electric motor feeds an IVT transmission, and there is an additional outlet for implements powered by up to a 200 kW electric motor.
A drum fixed to the tractor carries up to 1,000 metres of cable, although the length can be extended as required, making it applicable to a variety of farming types, including some broad acre operations.
In the field, the cable is fed out and reeled in while guided by a robot arm to keep the operation friction-free and at the low load on the tractor. An intelligent guidance system is also used to prevent the tractor from running into or over the cable.
During working operations, the tractor follows preset rows autonomously at operating speeds of up to slightly more than 12 m.p.h. The vehicle can also be guided manually using a remote control, which is particularly useful when manoeuvring the tractor to start work on field borders, for example.
A power supply of 2.5 kilovolts AC is required, and the GridCON tractor uses a 700 volts DC bus for electric power distribution both onboard and for implements. The machine employs a cooling infrastructure for off-board electrical use, while total efficiency of the drive train is in the region of 85 percent.
The total empty weight of the working prototype GridCON tractor including cable drum and robot arm is about 8.5 tonnes, so it is about the same weight as a conventional John Deere 6195R tractor but with twice as much power. John Deere says its research engineers are aiming to reduce the weight further by at least one tonne.
The concept also offers the twin benefits of noiseless and emission-free operation. As well, compared to battery-powered tractors, the GridCON tractor delivers around 50 percent lower machine and operating costs.
Researchers in Germany have modelled the pairing of additional units in the field in a daisy-chain configuration, covering larger acreages with greater efficiency for refilling in planter and seeders operations.
The GridCON project is funded by the German economic affairs and energy ministry and managed by the German Aerospace Centre eV in Cologne. It is a joint project of John Deere, the University of Kaiserslautern and BAUM Consult GmbH.