Design Of The Multidimensional Maggots Sieving Machine Among Maggots Handling Livestock Excrements

China is the largest pig breeding country around the world, about half of the global livestock pig is breeding in China. With the development of pig and other livestock breeding industry, a large amount of excrements are generated, especially solid excrements which leads to great pollution of the environment in our country. Most livestock excrements are directly discharged without any treatment which causes serious environmental pollution and waste abundant resources. Treated livestock excrements are good for breeding maggots and have become the hot topic of the breeding industry. Maggots can not only consume large amounts of livestock excrements, but also as protein supplement in feeding animals. However, the technology of using treated livestock excrements to breed maggots has just started in China, which greatly falls behind the developed countries. The characteristics of maggot breeding industry currently in China are small scale, simple technology, low processing depth, backward sieving technology of maggots and substrates. The main reason of un-forming full scale industry chain is the low level of mechanization and automation of sieving machine between maggots and substrates and poor controllability of sieving system which limit the development of maggot breeding industry.The multidimensional maggots sieving machine was designed for maggots handling livestock excrements industry for the above reasons. The sieving machine was able to improve the sieving efficiency. This machine had great value and broad prospect of presenting theories and designing practical equipment of vibrating sieve. The research contents of this paper mainly include:Firstly, movement theory of substrate was researched based on DEM. The model of traditional reciprocating sieving machine was established. The force and sieving probability of single substrate particle was analyzed. The geometric models of substrate particle and sieving mesh were established. Collision model between two substrate particles was determined, parameters of which were calculated, including contact force, elastic coefficient and damping coefficient. The DEM solving process of substrate particles was analyzed.Secondly, structure was analyzed and a parallel mechanism was selected. Four movement forms of parallel mechanism about 3T, 2T1 R, 1T2 R and 3R were present, detailed structure of which was analyzed with robot topology theory. One movement form of parallel mechanism was selected to become the main model of the multidimensional maggots sieving machine among maggots handling livestock excrements.Then, kinematics was analyzed and simulation was carried out. Mathematical model was established based on the selected main model of the multidimensional maggots sieving machine. Positive and inverse equation of kinematics that used mathematical methods and theories of higher institutions was calculated, which was lead to MATLAB to acquire theoretical motion curve. 3D model of sieving machine was established by Pro/E, it was lead into ADAMS by interface software Mech/Pro to acquire simulative motion curve after adding drivers. The theoretical curve and simulative curve were compared to verify the correctness of the positive kinematic equation. Velocity and acceleration were analyzed and curves of them were acquired. Decoupling of the mechanism was analyzed based on the positive and negative Jacobian matrix. Singular configuration of the mechanism was analyzed based on Jacobian algebraic method.Next, influence factors of sieving rate were analyzed. 3D models of substrate particle, maggot and geometry were established by Pro/E based on the selected main model of the multidimensional maggots sieving machine, then they were lead into EDEM to simulate collide. The sieving rate of different frequency and amplitude were explored with different movement forms of sieving frame, which was also explored with different DOFFinally, relevant experiments were carried out. A prototype of the multidimensional maggots sieving machine was manufactured. Position and orientation experiment and impact of sieving rate of DOF were carried out to acquire the relevant test data based on suitable test instruments and corresponding test principles and steps.