LiDaR sensing to monitor straw output quality of a combine harvester

Combine harvesters play a key role in agriculture as threshable crops take up about two thirds of the worldwide arable land. From an economic perspective there is a continuous demand for increased productivity of these machines, but the limits for the outside dimensions have been reached and the increased processing efficiency should not compromise the quality of the end product.The reduction of the straw length in the threshing section of a combine harvester is considered to be an important indicator for the crop processing quality. An aggressive threshing action or discontinuous flow of the crop material invokes high impact and friction forces on the crop. This breaks up the straw, resulting in a swath of low volume which complicates the subsequent baling process. Therefore, the impact of the settings of the threshing process on the straw quality, expressed in terms of the swath volume has been assessed in this study. An experimental design involving different combinations of machine settings has been applied and for each of these setting combinations the resulting swaths have been scanned with a LiDaR (Light Detection and Ranging)-sensor. By a backward stepwise regression a quadratic relation between the concave clearance and rotor speed setting and the swath height was found (R2 = 0.79). All terms in the model were significant (p value of F-statistic <0.05). The observed relation between machine parameters and straw quality is interpreted as a combination of forces on the crop and residence time of the crop in the threshing and separation section. Insight in the interaction of crop and machine is gained that could be a useful input for optimizing the settings of the threshing and separation section.

► Identify combine harvester settings potentially aggressive to straw. ► Damaged straw results in flat swath. ► Feasible to measure swath height with LiDaR sensor in field conditions. ► Non-linear relation between certain settings and swath height. ► Straw damage combined effect of impacts and transport in process.