Research On Eccentric Hole Type Seed-feeding Device In Rapeseed Displacement Ddetection System Experiment

This paper focuses on Eccentric hole type seed-feeding device as the main body of research,along with the mechanism of oilseed rape movement via the device and the Agronomic needs of rape seeding. We also uses related sensors and motor control theory to seed-feeding device detection and control. Various aspects of researches are as the following.(1).Seed rate via the seed-feeding device detection.The weight change of the metering box per unit time can be seem as likely to the current output volume,to detect the principle of pressure sensor,via the weight of the seed-feeding box changes’detection. We use the STM32as a central processing unit to analyze the current seed feeding box weight by pressure sensor data, amplify circuits and A\D transforming circuits via pressure sensor’s tiny voltage design,in addition to eliminate noise effects on the readings through a new filtering algorithm.(2).Displacement detection error compensation.The stress of the pressure sensor value equals to metering box weight under static conditions,but when it is affected by the mechanical vibration,the force is related to the acceleration,velocity, displacement and weight of the seed feeding box. We establish the vibration mathematical model by theoretical analysis:F=ma+Cv+Ks+mg.We detect the acceleration of the seed-feeding box via the acceleration sensor,conclude the velocity and displacement by integral principle and programming method,indicating the vibration model to calculate the current weight of seed-feeding box.(3).Displacement control system.There exits empirical formula between the seed rate(q) and the rotate speed of feed shaft(n):q=0.2283n+0.6683.We conduct precision adjustment of the rotate speed of feed shaft by the displacement control system made up by servo motor and servo drivers.We calculate the actual seed rate by detecting and calculating the weight increase of seed-feeding box,and figure out the difference by comparison with seed rate needed,draw the actual seed rate to real need via adapting the fuzzy serve system to adjust the metering device motor speed.(4).The bench test indicates:Variable metering system can conduct variable seeding in accordance to the need under static condition.The difference actual and theoretical seed rate is controlled strictly within3%or so and the uniformity coefficient of variation is confined to7%,which can satisfy the agronomic needs of rape seeding.Under the condition of vibration,displacement compensation system can do well in eliminating the effect vibration inserts on metering box weight values.The difference between actual and needed seeding rate enhances to about4%,plus the uniformity coefficient of variation is within8%.The rapeseed variable control system designed in this paper can accurately detect the actual seeding rate and weight of seed-feeding box under various working conditions.It can also conduct adjustment of metering shaft rotational speed of the motor according to seed rate,draw actual rate to rate needed,to enhance the accuracy of rape seeding planting.