Abstract:In order to solve the problems of low efficiency, low fruit picking rate and large damage rate in the harvesting process of high-acid apples, a hydraulically controlled high-acid apple vibration picking machine was developed according to the actual harvesting needs of high-acid apples in Qingdao, China. Based on the working principle of vibrating picker, the structural design of vibrating picking device, excitation device and hydraulic control system was completed, and the clamping force of the clamping pliers on the trunk was calculated and analyzed to be 7254N, and the clamping height range of the clamping pliers was 12~103cm. The dynamic model of fruit-branch pendulum of high-acid apple was established, the fruit shedding conditions were analyzed, the differential equation of fruit vibration was obtained, and the vibration frequency, amplitude and clamping height were determined as the main influencing factors of picking effect. ANSYS software was used to simulate the free modal response and harmonic response of the fruit tree model, and the results showed that when the vibration frequency was 9~12Hz,the amplitude was 1~2cm, and the clamping height was 40~70cm, the displacement of the third-order and second-level branches was the most obvious. In order to determine the optimal working parameters of the picker, a three-factor three-level combination field experiment was carried out to obtain a regression model of fruit picking net rate and fruit damage rate, and the test data and regression model response surface were analyzed and optimized by Design-Expert software, when the vibration frequency was 10.0Hz, the amplitude was 1.6cm and the clamping height was 58.7cm, the fruit picking net rate was 95.9% and the fruit damage rate was 1.3%, which met the quality requirements of high-acid apple harvesting.
