Study On Typical Sandy Shrub Stumping Technology And Equipment

Sandy shrub is the important plant for preventing and controlling desertification, and improving desertification land in Chinese western region. And it plays an important role in managing desertification hazards in our country. Owing to its biological characteristics that it needs to be stumped timely, mostly sandy shrub shows various degrees of degeneration because it hasn’t been stumped in time, and now it runs the risk of secondary desertification. Sandy shrub not only has great ecological benefits, but also has great economic benefits. The paper is one of the key tasks of national science and technology support project. The research purpose is to break through the key sandy shrub mechanize harvesting technology, and to develop sandy shrubs harvesting equipment that adapted to Chinese situations.Sandy shrubs growing environment and biological characteristics in our country and relevant research dynamic at home and abroad were discussed. On the basis of summarizing and analyzing the fundamental characteristics and cutting performance of typical sandy shrubs salix and caragana korshinskii, design and experiments on reciprocating shovel type cutter, reciprocating single acting type cutter, rotary sling blade type cutter and saw blade were carried out. The results indicate that the reciprocating cutter is suitable for harvesting young and low diameter shrub in flat terrain, and the circular saw blade cutter is suitable for harvesting more than3years old shrub with higher degree lignifications. However, reciprocating shovel type cutter and rotary sling blade type cutter are not suitable for harvesting shrub.Based on the cutting efficiency, energy consumption and cutting effect of the cutter, comprehensive comparison and optimization of cutting mechanism and motion parameter were carried out and two kinds of shrubs stubble machine were designed. In order to harvest young and low diameter shrub, a kind of reciprocating double knife shrub harvester with symmetrical double crank and rocker mechanism was designed. The relationship between the displacement, velocity, acceleration and the crank rotation angle of cutter was analyzed and was verified by simulation. According to the shrub tending problem on complex growth terrain conditions and higher degree lignifications, a self-propelled saw-blade shrub stumping machine with transverse and longitudinal profiling function was designed. The relationship between disc diameter, number of teeth, and feed rate of each tooth, rotation speed of saw-blade and machine speed was analyzed. New shrub stumping profiling method, a combination of artificial manipulation profiling and machine self-adaption profiling, was proposed.According to the harvesting experiment on2-year-old caragana microphylla by using reciprocating double knife shrub harvester, following results were obtained. The best work parameters are crank rotation speeds n is632r/min and cutting speed ratio λq is1.6and the indicators are the fraction defective of stubble height is less than or equal to2.5%, the broken stubble rate is less than or equal to3.1%, loss cutting rate is less than or equal to2.5%, and productivity is0.38hm2/h.The experiment of self-propelled saw-blade shrub stumping machine on5-year-old salix mongolica was carried out, and the best stubble parameters were concluded as follows. The proper linear cutting velocity is50m/s, and the travel speed is0.44m/s when the number of shrubs plant is less than80per clump, and is0.34m/min when the number of shrubs plant is from80to110per clump, and is0.24m/min when the number of shrubs plant is more than110per clump. The number and diameter of the plant of salix psammophila clump, and the dune height have larger effect on machine operation speed. The machine walking speed should be adjusted timely according to brush growing situation. Research and experiment results show that self-propelled saw-blade shrub stumping machine designed in the paper can realize profiling combined manual copying and machine adaptive imitation, and can meet the machine walking requirement combined lowest harvesting walking speed on the brush and highest moving walking speed among the brush. The designed articulated body structure can make sure that the joint-point-centered arc cutting trajectory of the cutting parts can be formed during stopping or walking. And it improves the machine flexibility, enhances the harvesting width, and increases the harvesting efficiency. The innovative structures, the profiling structure combined double four-linkage structure and extension spring and the rotating-shaft articulated structure between mainframe and cutting parts, can implement self-adapting transverse and longitudinal profiling. The counter-outward-rotating circular saw-blade cooperated with inverted V-induction-rod can collapse the after cut branches and create conditions for branches removed from the field efficiently in future.The sandy shrub stubble machine designed in the paper shows good working performance in the field experiment. It can meet the requirement of stumping and rejuvenation for different types of shrub, and has a good application prospect in our country.