Development of a novel mechatronic system for mechanical weed ...

6 Summary
Summary
Neither a mechanical nor a physical system for effective intra-row weed control
in row crops has been commercialised until today. Online detection of single
plant position and plant/weed distinction are the bottlenecks of intra-row
weeding systems, but considering the rapidly growing research and
development in this field, it is expected that appropriate systems will soon be
available. In the meantime, construction and adjustment possibilities of
implements which take into account the role of soil properties and mechanics
need to be optimised toward universal intra-row weeding tools, which can be
used in different plant spacing systems, different plant intra-row distances and
growth stages.
In this work development of a universal intra-row weeding tool is presented from
the idea to the first prototype.
Accurate intra-row weed control requires either detection of the position of every
crop plant or detection of every weed. In this work a simplified methodology and
system for plant position detection based on the spectral characteristics of crop
plants combined with the context information of the planting pattern was
developed and tested.
The experimental results showed that the combination of the RGB sensor and
laser sensor can be used for accurate detection of the plant centre position
independently from illumination conditions. In the conducted experiments the
maximum deviation of the estimated centre positions from the plant measured
centre positions, detected by RGB sensor, was 31 mm, whereby 50% of the
samples were inside the interval 0 to 5 mm and 90% of the samples were inside
the interval 0 to 16,9 mm. For the laser sensor, the maximum deviation of the
estimated centre positions from the plant measured centre positions was 25
mm, whereby 50% of the samples were inside the interval 0 to 3 mm and 90%
of the samples were inside the interval 0 to 6.9 mm.
The main shortage of the presented system is that sensors require ad-hoc
parameter adjustment before the measurement to provide good plant detection.
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