Design and Experiment of Device for Ring-cut Cluster Branch Separation Unit of Green Prickleyash Picking Machine

During harvest of green pricklyash，most of protruded oil glands on peel are easy to break，which causes fruit to turn black after dry，and effective components volatilize，which seriously affects quality.Damage degree of oil bud of green pricklyash directly affects its quality.In order to realize mechanized harvesting of green pricklyash，under premise of ensuring low damage rate of oil bud，based on principle of branch loop cutting，a kind of spike and branch separation device of green prickleyash harvester was designed.Structural parameters and operation parameters affecting the harvest were obtained through theoretical analysis.According to physical characteristics and machining economy of branches，structural parameters and operating parameters were optimized.Angle of ring cutting edge，speed of ring cutting tool and feeding speed of branch were selected as experimental factors.Harvest efficiency and damage rate of oil bud were used as evaluation indexes.Single factor and quadratic orthogonal rotation combination tests were carried out.Response surface method was used to analyze test results，and multi-objective optimization algorithm of Design-Expert software was used to optimize parameters.Results showed that，main factors affecting harvest efficiency and damage rate of oil bracts were feeding rate of branches.Effects of various factors on harvesting efficiency and damage rate of oil bracts were in descending order from the top to the bottom：feeding speed of branches＞revolving speed of ring cutting＞angle of ring cutting edge.With increase of feeding speed of branches，harvesting efficiency increased rapidly，and damage of oil bud increased sharply after first slow increase.With increase of rotary speed of ring cutter，harvest efficiency did not increase obviously.When feeding speed was less than 0.4 m/s，damage rate of oil bud decreased slightly at first，then stabilized，and finally increased slightly with increase of rotary speed of ring cutter.When feeding speed was greater than 0.4 m/s，damage rate of oil bud decreased steadily with increase of rotary speed of ring cutter.Optimal parameter combination of the device was as follows：rotation speed of ring cutter was 2 800 r/min，feeding speed of branches was 0.45 m/s，and angle of ring cutting edge was 25°.Field experiment with prototype showed that harvesting efficiency and damage rate of oil bract was 50.7 kg/h and 6.7% respectively，which were better than current manual picking.