Study On Basic Physical Properties And Vibration Harvested Parameters Of Raspberry

Raspberry as a new fruit has the very high economic value and good prospects for development, it can be a food fresh fruit and raw material to deep processing. Because of the raspberry tree is short and branches is soft, meanwhile raspberry is soft and juicy fruit, so raspberry mainly picked by manual, it belongs to the labor-intensive industries. With the increase of labor cost, raspberry harvesting mechanization has become a hindering to the development of the raspberry scale and industrialization. The study on raspberries physical properties and by analyzing the compressive limit of raspberry fruit, all that can provide reference basis to reduce the injury in harvesting, transportation and storage. Through the study on stalk stretching force of different maturity raspberry and the influence law between vibration position, amplitude, frequency and harvesting rate, immature raspberry harvesting rate all that can provide theory and reference for the development and design of harvesting system mechanical. Under such a background, this paper study on raspberries physical properties and vibration harvesting parameters, the main work is as follows:(1)The basic physical parameters of raspberry fruit are measured. The quality of two varieties raspberry fruit are measured by electronic scales and the raspberry along the direction of raspberry fruit stalk(altitude) and the stalk vertical direction(diameter) is measured by vernier caliper. The result shows that the diameter of the DNS-1and the Re-velie respectively is(17.8±4.6) mm,(19.1±5.1) mm, height respectively is(17.5±4.5) mm,(18.7±6.6) mm, quality respectively is(2.6 ±1.5) g,(2.9±1.7) g.(2)The compressive limit of raspberry fruit is determined by using stalk stretching force along the direction of raspberry fruit stalk pressure(vertical pressure) and the peduncle vertical direction(lateral pressure). The compressive limit of raspberry fruit is obtained by analyzing the pressure curve of different maturity of raspberry fruit in two directions. The results show that the vertical pressure and lateral pressure of DNS-1 respectively is(1.04±0.58) N,(0.71±0.40) N. vertical pressure and lateral pressure of Revelie respectively is(1.08±0.48) N,(0.73±0.42) N. In harvest period, with the increase of maturity, the vertical and lateral pressure of two varieties raspberry tend to significantly reduce the limit. Along with the harvest date delayed, the vertical and lateral pressure of two varieties raspberry generally showed a trend of decrease. The vertical and lateral pressure of two varieties raspberry harvested in July 16, 2014 date were significantly higher than the other four times, within the last four harvest date vertical and lateral pressure change trend is gradually slow down. In the same harvest date, the same maturity of raspberry fruit,vertical pressure was obviously higher than lateral pressure.(3)Different maturity raspberry stalk stretching force and the stalk stretching force changing with the harvest time are determined. Stalk stretching force with different maturity and different harvest time raspberry stalk stretching force experiment was carried out, through the analysis of stalk stretching force curve, we get different maturity and different harvest time of raspberry stalk stretching force. The results showed that DNS-1and Revelie raspberry stalk stretching force respectively is(1.09±1.02) N,(l.02±1.04) N. On harvest period, two varieties of raspberry stalk stretching force along with the harvest date delay is roughly decreases gradually; the stalk stretching force that picked on 16 July significantly higher than the other four harvest date, both varieties raspberry shows the trend. In the last four harvest date, stalk stretching force decreased greatly. In harvest period, stalk stretching force of not ripe fruit II is significantly higher than the other three. To, Ⅳ III and Ⅴ maturity raspberry, stalk stretching force in different harvest time applied for a certain difference, but the difference is not big and the differences between the two varieties are slim.( 4) Established the mathematical model between vibration position, amplitude, frequency and harvesting rate, immature raspberry harvesting rate, then analyzes the influence law between three factors and harvesting rate, immature raspberry harvesting rate by designexpert. The results show that when the vibration frequency of 15-19 Hz, amplitude of 21-26 mm, vibration clamping position of 0.5, harvesting rate is more than 70 %, immature raspberry harvesting rate is less than 16 %. The optimal vibration harvesting parameter are that vibration position at 0.48, the amplitude of 23 mm, the vibration frequency of 18 Hz, where raspberry harvesting rate and immature raspberry harvesting rate respectively is 71.0 % and 15.6 %.(5)Suspension test were tested on agricultural material suspension speed test-bed, then established the suspension speed range of mature raspberry fruit and immature raspberry fruit, raspberry branch, raspberry stalk, whole and simple leaf, the result shows that suspension speed range respectively is 15.4-17.9 m/s,11.2-14.6 m/s,3.6-5.7 m/s,9.8-12.3 m/s,3.1-4.2 m/s,2.2-3.3 m/s. The overlapping of each material suspension speed range is not big, suspension speed of mature raspberry fruit with other materials have larger gap.