Agriculture Reference
In-Depth Information
Fig. 12.4 Systems for material fl ow measurement in forage harvesters
Auernhammer et al. ( 1997 ) reported on the accuracy of a sensing system that
relies on gamma ray absorption by the fl ow of maize forage in the spout of a
forage harvester. The evaluation was based on control weighing a very high
number of trailer loads. After optimising of the meter, the standard deviation of
the relative error was 3.3 %. For a system that relies on the distance of the feeder
rolls and with whole crop barley, Ehlert ( 1999 , 2002 ) obtained a standard devia-
tion of the relative error of 5.9 %. Finally when used with maize, the standard
deviation of the relative error with the friction compensated curved plate in the
spout as developed by Missotten et al. ( 1997 ) was 2.7 %.
Research on systems for local yield detection in round balers , square balers and
self-loading trailers (Auernhammer and Rottmeier 1990 ; Behme et al. 1997 ; Sauter
et al. 2001 ; Shinners et al. 2003 ) initiated a development which resulted in the com-
mercial availability of weighing systems for large square balers. These systems are
able to deliver the weight of each single large square bale by integrating load cells
in the bale chute and to record this information together with the position (and mois-
ture) of the bale in the fi eld. One manufacturer offers the individual identifi cation of
the bales using RFID tags - that are capable to locate via r adio- f requency - together
with the recording of the bale weight, material moisture and bale location. However,
because the systems are not able to correctly measure the increase of the weight of
a bale until it is tied and passes the chute, it is not possible to obtain the site-specifi c
yield in the fi eld. The time- and distance lags that are involved prevent this.
Search WWH ::




Custom Search