Automatic guidance can preserve precious plants

29 June 2001

Automatic guidance can preserve precious plants

Accidentally digging up

valuable plants when using

an inter-row cultivator could

soon be a thing of the past

as automatic guidance

systems gather pace.

THE ability to drive straight and true among rows of growing plants has long been a required skill for operators of inter-row cultivators – a nervous twitch of the steering wheel can easily wipe out metres of valuable young plants.

However, inter-row cultivators can now be specified with numerous automatic electronic steering aids to preserve plant life, as growers search for low-cost, effective weed control systems.

"There is a greater emphasis being placed on chemical-free weed control systems, particularly for organic, vegetable and root crop growers," says Philip Garford of Garford Farm Machinery.

Garford is now offering its Robocrop Video Guidance (RVG) system as an option on inter-row cultivators. "Robocrop is the culmination of four years work by the Silsoe Research Institute after it went in search of the perfect image tracking system," he says.

Claimed to be accurate from the two-leaf stage in sugar beet, Robocrop uses colour image separation to identify the crop, making it reliable in a wide range of lighting conditions and soil types. An in-cab visual display keeps the operator informed of the tracking process.

"Robocrop tracks the crop using a combination of multiple row imaging and dead reckoning," says Mr Garford. "It then alters the position of the cultivator on the tractors three-point linkage using a hydraulic side-shift mechanism to keep the cultivator in the correct position between the rows."

According to Mr Garford, accurate row tracking has been maintained at speeds of over 12kph. And in extreme weed infestations where it is virtually impossible to identify the row, Robocrop will inform the operator.

The Advanced Tool Control (ATC) system is a similarly advan-ced, automatic guidance device from Danish manufacturer Eco-Dan. Imported by Tony Deptford Agricultural Marketing of Boston, Lincs, ATC uses a vision system, guidance frame and wheel sensor.

The vision system uses two cameras sited on the front of the tool bar frame, above the row. Each camera continuously photographs 1.1m sections of its own plant row, with images being transferred by computer to a reference line stored in its memory.

The computer then checks the position of the cultivator in relation to the reference line, and any deviation results in signals being sent to the hydraulic system to adjust the guidance frame accordingly, to keep the cultivator firmly between the rows.

Eco-Dans guidance frame uses an inner and outer A-frame which separates the cultivator from the tractors three-point linkage. A-frame alignment can be altered hydraulically by up to 15cm to either side of a central position. Such a system clearly has its advantages for those carrying out inter-row cultivation across gently sloping ground.

Track mark

In addition, a wheel assembly with sensor is fitted at the front of the implement to detect if the cultivator is working, raised or lowered. ATC can also be specified as a Combi-Vision system which follows a track mark made in the soil, enabling cultivation to be carried out at early growth stages. The ATC system is priced from £3950.

The latest versions of Tim Thyregod TRV tractor-mounted inter-row cultivators being marketed by Kongskilde UK also offer automated steering systems.

Automated weeding with the TRV is achieved using what the firm describes as a Vision Control Steering (VCS) system, which is a computer-based optical system that steers the row units and allows them to cultivate close to young plants.

VCS operates using two digital cameras located about 70cm above the row on the cultivators tool bar. Both cameras are connected to an in-cab control box, which allows the operator to set the system according to row widths and the crop being grown.

Colour recognition

The digital cameras identify the crop as lines, supplemented by colour recognition. With a line of growing plants identified, the cameras send an impulse to the hydraulic system, which corrects the position of the cultivator through a hydraulic side-shift linkage between the cultivator and the tractors three-point linkage.

Using digital cameras, Kong-skilde claims its system allows early cultivation – when plants are between 2cm and 2.5cm in size. It also allows the operator to work at forward speeds of 10-14kph.

Weeding at earlier growth stages is possible, says the firm, if a tracking wheel is fitted to the drill to leave a visible marking that can be followed. This is achieved by reversing the camera to activate a laser – the laser beam then follows the track marking and inter-row steering is maintained.

The TRV inter-row cultivator is available in six, 12 and 18 rows, and is suitable for row widths from 25-75cm. &#42

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