Optimization design of non-circular planetary gear trains pricking hole mechanism based on MATLAB

Abstract: In recent years, as China government policies in agriculture are focused on improving agriculture machinery, deep-fertilization liquid fertilizer applicator with high efficiency, low price, easy operation and environment protection attracts more and more concerns. Deep fertilization for liquid fertilizer is a technology that liquid fertilizer is application accurately in 120-150 mm depth soil, which decreases fertilizer volatilization, increases crop's nutrient absorbance in fertilizer, decreases environmental pollution brought by fertilizer, and increases crop yield and quality. Deep fertilization for liquid fertilizer is to make the liquid fertilizer into the soil. Northeast Agricultural University developed all elliptic planetary gears for pricking hole mechanism of 1YJ-140 type deep-fertilization liquid fertilizer applicator. Although the mechanism was obtained via using design method for obverse operation, there were a certain blindness in the process of seeking the optimal parameters and a long process of seeking parameters. The transmission part of pricking hole mechanism adopted all elliptic planetary gears so its transmission ratio was fixed. It was difficult to find a perfect path curve. So the non-circular planetary gear trains for pricking hole mechanism was proposed. Several date points on the motion trace of fertilizer-spraying needle tip were selected, and then the curve fitting technique of cubic non-uniform B-spline was applied to control and ascertain the whole trace curve. The inverse kinematics model of the pricking hole mechanism was established on this basis. Then, other parameters could be reversed easily. To meet agronomic requirements of verticality and hole mouth size for deep-fertilization liquid fertilizer machine' fertilizer-spraying needle when it came in and went out of the soil, the simulation software of reverse design and kinematics analysis was compiled, which was for pricking hole mechanism of the non-circular gear planetary system . The software avoided the blindness that the obverse design method tried the wrong parameters. By changing the coordinates for some types of value points on static trajectory to control fertilizer-spraying needle point posture, the reverse process, simulation result and mechanism motion process were showed intuitively and dynamically, and the optimized parameters were that the gears' center distance was 61.5 mm, the distance between planetary gear center and fertilizer-spraying needle point was 161 mm, the cave mouth width was 28 mm, the track height was 252 mm and the width was 182 mm. High-speed photography bench was established and tested. The relative motion trajectory of fertilizer-spraying needle point and the key point posture were inspected in the process of actual operation. The results showed that the fertilizer-spraying needle point trajectory height was 246 mm and the width was 188 mm, and the accuracy and feasibility of reverse design and analysis were validated. This study uses many methods such as theoretical analysis mathematics, computer numerical simulation, high speed camera technology and rack experiments, and provides the reference for improving agricultural machinery quality and fertilizer applicator design level.