Experimental Study On Working Parameters Of Vibratory Blueberry Picking Devices

Blueberry harvesting operation mainly use of artificial harvesting in our country, which is labor-intensive, inefficient and costly. Blueberry harvesting mechanization is the inevitable trend of the development of blueberry industry. Working Parameters of picking devices is an important basis for reasonable designing new type of picking machinery devices. But there is less working parameters research on blueberry picking device currently, domestic technology of blueberry picking device is undeveloped, which exists problems of poor harvesting effects, larger injures to fruit and trunk, etc. Therefore, It is necessary to study on the working parameters of blueberry picking device, which could provide reasonable design basis for blueberry picking machine.Harvesting machine-fruit tree simplified dynamic model of the mass-spring-damp system were constructed.Through model solution and analysis, it obtained that fruits’displacement, velocity and acceleration changed periodically during vibratory harvesting, the main parameters which affected fruit inertia force and vibration shedding were excitation frequency and. amplitude.Test and analysis on variation of blueberry’s binding force during mature period. The results showed that binding force of blueberry fruit during mature period changed between0.48N and0.84N, and decreased as time increased. The surface of blueberry turned blue about5days, binding force significantly reduced, ranging from0.48N to0.57N, and the average value was0.53N. Anti-tensile force and binding force were highly strong correlated with time, but did not correlate significantly with temperature and relative humidity. Shear resistance was strong correlated with time, and moderately correlated with temperature and relative humidity. Ratio of anti-tensile force and shear resistance had gradually converged to2.04trend. BP neural network which extracted by principal component after trained and debug was available for prediction and analysis of blueberry’s binding force.Blueberry picking test device was made after overall structure design and control system design. The test device which had a simple structure and wide accommodation could applied not only to the vibration harvesting test of blueberry but also other small berry.Vibration harvesting test was conducted by using blueberry picking test device. The results showed that primary and secondary order which affected ripe fruit rate was excitation frequency, amplitude and acting time. Excitation frequency had significantly effect on unripe fruit rate while the effect of amplitude and acting time did not significantly. Optimal parameter combination within the range of test level was obtained with excitation frequency1240r/min, amplitude10.3mm and acting time8.4s. excitation frequency could significantly increase ripe fruit rate while unripe fruit rate also increased. The increase of amplitude and acting time could increase ripe fruit rate, but has little effect on unripe fruit rate.The movement of blueberry fruit in the process of vibration harvesting based on high-speed camera technology was analyzed. The result shows that blueberry fruit was mainly under the load of torque and bending moment in the process of shedding. The larger instantaneous velocity of ripe fruit is easier to shed. And ripe fruit is easier to shed than unripe fruit. The closer the fruit away from the local oscillator is easier to shed. There was relative motion between blueberry fruit and collateral. Blueberry shed when the inertia force of shedding is greater than the binding force.The research results in this paper can provide the technical basis for design and development of blueberry picking device. With a certain guiding function and practical significance for mechanized harvesting blueberry.