Warwickshire farmer’s son Tom Beach has recently achieved notoriety by designing, developing and building a remote controlled vegetable harvesting system based around a John Deere 6210 tractor. Simon Henley went to see the machine in action.
Tom Beach is a farmer’s son who works part-time on the family’s 100 hectare farm near Alcester. Here at Mudwalls Farm they specialise in growing purple sprouting broccoli, a winter crop typically picked between September and March.
Mr Beach studied Agricultural Engineering at Harper Adams and has since focussed his work on robotics and autonomy in the agricultural industry. Having also spent four-years working for several large vegetable growers, his experience has taught him a great deal when it comes automatization in the agricultural workplace.
One of his most recent projects has been to improve the efficiency of the harvesting process on the family farm. Picking purple sprouting is a labour intensive process which requires a gang of pickers to individually harvest the flowers. Knowing what to harvest and what not too is important to keep the plants producing their purple buds throughout the season.
Because this is a winter crop, harvesting frequently requires working in the rain and cold, walking through muddy fields. Picking at Alcester is mainly handled by an Eastern European workforce, who slowly harvest the purple sprouts by walking through the beds of plants ready for cropping. The beds can extend the full length of the field, so besides the picking there is also a lot of walking to do.
As the purple sprouts are picked, they are packed carefully into shallow crates, which are stacked on a flat-bed packing trailer towed behind a tractor. In normal circumstances, the tractor would require a driver to inch it forward a few feet at a time while the gang works its way across the field.
Having witnessed this process thousands of times, Mr Beach decided he wanted to improve the efficiency of the harvesting process. With the support of farm manager Russell Duggan, his idea was to develop a remote control system which would allow the tractor to be controlled by the farm foreman on the packing trailer, thus eliminating the need to tie up one person sitting in the tractor cab.
To define converting a 25 year old tractor into a remote controlled vehicle as ‘daunting’ would be a profound understatement. Initially, Mr Beach decided to convert a New Holland orchard tractor, equipped with a hydrostatic transmission. However, it was soon realised the little blue model did not have the power to pull the packing trailer, so Mr Beach decided to focus his efforts on robotising the farm’s John Deere 6210.
The first problem he faced was deciding how to control a tractor with a mechanical semi-powershift gearbox. He needed to control both the right-hand forward-reverse selector and the four-speed powershift lever. To do this, he elected to use two electronic actuators, which were attached to a bespoke frame mounted in front of the lever console and bolted to the floor.
“I drew the electrical circuit for the system on paper, so I could suss out how to make it work,” explains Mr Beach. “I then added a numerical tag to each wire to identify the circuit it related to, so I could quickly diagnose any faults and problems which materialised.
“The remote-control system is activated using a master switch mounted on a control box in the cab. The control box also features an over-ride switch, so the tractor can be driven manually.”
He adds: “To operate the gearbox, the electronic actuators on the gear levers are equipped with sensors to calculate their exact position. This allows them to extend or retract to the precise point required to either engage, select or change gears.
“During the design phase, I decided the actuator system should not be allowed to select reverse. This was purely from the perspective of safety. If you do need to reverse the tractor, you over-ride the system on the control box, so it can be driven manually.”
Steering the tractor was another issue which faced Mr Beach. Working in muddy fields, sometimes on slippery inclines, the tractor could not be relied upon to maintain a straight course without a driver.
To overcome this problem, Mr Beach used electronic sensors to control the oil flow on the tractor’s double acting steering ram, to identify which way the wheels should turn. Having established how to control the position of the front wheels, the next challenge was to provide hydraulic pressure to the steering ram.
In normal operation, the hydraulic pressure would be provided by the power-steering hydraulic system, which is activated by turning the tractor’s steering wheel. Since the position of the wheels was now being controlled electronically, the solution was to provide hydraulic power from the tractor’s rear spool valves.
With some bespoke hydraulic pipes connected to one of the spool valves, the spool lever in the cab is placed into the constant pumping position. This provides constant hydraulic pressure so the steering system can now be remotely operated without turning the steering wheel.
For normal operation, the remote control system is once again over-ridden and the spool valve taken out of constant pumping position. This returns the control of the tractor’s front wheels to the steering wheel.
Out in the field, once the master switch in the cab is engaged, the tractor is controlled by the farm foreman using a control box mounted on the packing trailer. A warning buzzer sounds three loud beeps during a three-second delay, before the tractor starts moving very slowly forward. Once underway, it can be steered effortlessly and stopped when required, so the pickers walking along side can continue their work.
To make life a little more pleasurable for the pickers, Mr Beach also designed and built a folding retractable canopy to protect the team from the elements. Designed to fold-up to less than 3m in width for road-legal transportation, the canvas roof and sides are mounted on an aluminium cantilever frame (also designed and built by Mr Beach) attached to the packing trailer.
With the canopy unpacked in the field, at the front of the folding structure is a portable 6m conveyor, onto which the pickers place the harvested purple sprouting. Equipped with an audible warning system which announces it is about to start, the conveyor shuttles the crop onto the packing trailer, where it is picked off the belt, placed into the packing crates and stacked.
Further safety measures include trailer brakes which automatically lock on when the tractor stops. This feature was achieved by reversing the trailer brake actuation system, so that hydraulic pressure is required to release them. While working, as soon as the remote control system stops the tractor, the hydraulic pressure shuts-off and activates the trailer brakes.
Other neat features integrated into this design are conveniently placed emergency stop buttons inside the canopy structure, which the pickers can use to stop the tractor if necessary. These shut-off the tractor’s engine, and once stopped it requires a manual re-set in the cab before it can be re-started.
The retractable canopy has also been equipped with a melee of LED light bars, providing all the lighting power necessary to cope with early morning winter starts.
Having watched this tractor working in the field, the performance of this rig can only be described as truly inspiring. There is nothing homemade or Heath Robinson about the way this set-up works, and you can bet your last Rolo this will not be the last example of agricultural automation we see from Tom Beach in the future.
Hydraulic power to the tractors remotely controlled steering, is provided by one of the tractors rear spool valves. Trailer brakes have been modified to automatically lock-on when the tractor stops.