Transducer for Measuring Force Exerted on Plant Stem

A strain gauge transducer was designed to measure force exerted by the gathering chains and stalk flipper on a whole-stalk sweet sorghum harvester. Stalks were adequately held when the spacing between the chains was adjusted to achieve an average force measured with the transducer, of 25.3 N (5.7 lbf). Maximum force was 38.5 N (8.7 lbf) and did not damage the stalk. Average crushing force for 15 stalks tested in the laboratory was 460 N (103 lbf). The stalk flipper exerted more force on the transducer; a maximum of 86 N (19.3 lbf) was measured. The transducer was sized to quantify force exerted on 20 mm (0.8 in.) diameter sorghums stalks, but the design concept could be used to quantify the force exerted on different size stems by various plant handling mechanisms on field machines.