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In this paper, BP neural network is used to collect header height, AMEsim is used to simulate and analyze header height adjustment hydraulic system, and fuzzy PID control is used to adjust header lifting hydraulic cylinder to stabilize header height. The experimental results of harvesting different crops show that under the header height automatic control system, the error between the actual height of crop harvesting and the set height is within 15 mm, and the harvesting effect is good, which can meet the automatic regulation requirements of the header height of the multi crop combine harvester. [ABSTRACT FROM AUTHOR]

Grain sieve losses are important parameters to judge the performance of cleaning shoes in combine harvesters. To keep grain sieve loss within acceptable limits, an impact-type piezoelectric sensor was developed for real-time monitoring. Rice grain and short straw particle models were established according to their physical properties, and discrete element method (DEM) simulations were carried out to understand their collision behaviour with the sensor. The influence of grain shape, straw length and impact angle on variations of the maximum normal contact force and force rise-time were analysed in detail. Differences in normal collision force, and force rise-time occurred which lead to corresponding differences in signal frequency and voltage amplitude. A signal processing circuit, which mainly consisted of a band-pass filter circuit and a voltage comparator circuit, was designed to discriminate for full grains. Field tests results indicated that measurement errors recorded by the sensor and checked against manually measurements were <4.48%.Highlights· Collision behaviour of rice grain and straw with the sensor was studied utilizing DEM simulations. · A signal processing circuit was designed to discriminate for rice grains. · Field tests results indicated that measurement errors of the developed sensor were <4.48%. [ABSTRACT FROM AUTHOR]

To improve the driving comfort of combine harvesters, driver seat low-frequency vibration and related driver ride-comfort problems were investigated on a Chinese CFFL-850 crawler-type full-feed combine harvester based on ISO2631. Driver vibration and driving seat transmission characteristics were measured under the following conditions: no-load idling, driving on the road, driving in the field, and simulated harvesting. The root mean square values composite vibration under four conditions were 3.63 m/s², 2.35 m/s², 3.34 m/s², and 2.67 m/s2 , respectively. For the same condition, the maximum root mean square scores of vibration component on driver whole-body occurred in the seat support surface (test point 1) and vertical direction (Z direction), which were 3.56 m/s², 2.05 m/s², 3.15 m/s², and 2.43 m/s², respectively. The test point 2 to test point 1 vertical-transfer function curve trends were nearly identical. Nearly all of the transfer coefficients were greater than 1 in the range of 1-50 Hz, therefore, the seat vibration attenuation performance was poor. Based on the analysis results, the driver seat structure was altered and a verification test was performed. The test results indicated that after an X-damping mechanism was installed, vibration acceleration, on the surface of the seat support under the road-driving conditions, decreased from 2.35 m/s 2 to 1.68 m/s2 . Under the simulated harvesting condition, the vibration acceleration decreased from 2.56 m/s2 to 1.46 m/s² . Nearly all of the seat vertical transfer coefficients were less than 1 within the frequency range of 1-80 Hz, therefore the dynamic comfort of the seat was ameliorated after structural improvement. [ABSTRACT FROM AUTHOR]

To reduce the inertial force of the oscillating sieve and return pan of a rice combine harvester, partial equilibrium was adopted. Firstly, based on the kinematic analysis of a slider-crank mechanism, the appropriate mass of counterweight intervals was achieved. Then, an ADAMS dynamic simulation was used to determine the optimum balance mass of the oscillating sieve and return pan individually. Considering the relative motion between the return pan and the oscillating sieve, the overall inertial force of the two parts would be reduced. The simulation results indicated that the optimum counterweight of the oscillating sieve was 15.5 kg based on an analysis of the movement tracks of the mass center and overall inertial force. The results also showed that the overall balance of inertial force not only reduced the counterweight but also decreased the overall inertial force of the oscillating sieve and return pan. Finally, a search for the most suitable crank initial angle of the return pan to reduce the overall inertial force and optimize the overall balance revealed three groups of initial angles: φ=0°, φ=45°, and φ=90°. The results indicated that arranging the initial angle of the crank of the oscillating sieve and return pan in the same position (φ=90°) was the most favorable for reducing the overall inertial force. In this situation, the optimum counterweight of the oscillating sieve was only 14.0 kg. The results can provide references for the design of the overall balance of the inertial force in the cleaning components of a combine harvester. [ABSTRACT FROM AUTHOR]