Analysis and Design of a Spatial Planetary Noncircular Gear Train for Rice Seedling Transplanting Based on Three Given Positions

2020 ◽  
Vol 63 (1) ◽  
pp. 165-176
Author(s):  
Liang Sun ◽  
Yuzhu Zhou ◽  
Hengmin Huang ◽  
Chuanyu Wu ◽  
Guofeng Zhang
Keyword(s):  
Lateral Displacement ◽  
Kinematic Model ◽  
Planetary Gear ◽  
Gear Train ◽  
Transmission Ratio ◽  
List Type ◽  
Gear Pair ◽  
Planetary Gear Train ◽  
Analysis And Design ◽  
Noncircular Gears

HighlightsA method for solving a spatial transplanting mechanism with noncircular gears is proposed.A new mechanism for transplanting rice pot seedlings is proposed.A trajectory with a small lateral displacement at the preparation phase is obtained.The working performance is validated by simulations and field tests.Abstract. This study proposes a method of solving the parameters of a spatial planetary gear train with noncircular gears to meet the requirements of wide-narrow row pot seedling transplanting (WPST). First, the planetary gear train was simplified to a spatial open-chain 2R mechanism (planetary carrier). A kinematic model of the 2R mechanism was derived from the three given homogeneous matrices describing the spatial position and attitude information of grasping, extracting, and planting seedlings. Second, the length of each link, attitude of each rotation axis, and relative initial angles were calculated. The model for solving the transmission ratio was deduced. A spatial planetary gear train configuration with a single planet carrier and two-stage driving was derived, in which the middle axis could be determined by combining the selected configuration, represented trajectory, and transmission ratio of each gear pair. Finally, a planetary gear train combining a noncircular gear pair and a helical gear pair was used in the WPST mechanism design. Simulations and tests conducted on a prototype confirmed the correctness of the theoretical model and the practicality of the design. Keywords: Noncircular gear, Planetary gear train, Spatial trajectory, Transmission ratio, Transplanting mechanism.

Novel approach for planetary gear train dimensional synthesis through kinematic mapping

2019 ◽  
Vol 234 (1) ◽  
pp. 273-288 ◽  
Author(s):  
Liang Sun ◽  
Zhenfei Wang ◽  
Chuanyu Wu ◽  
Guofeng Zhang
Keyword(s):  
Angular Displacement ◽  
Planetary Gear ◽  
Gear Ratio ◽  
Gear Train ◽  
Transmission Ratio ◽  
Dimensional Synthesis ◽  
Open Chain ◽  
Planetary Gear Train ◽  
Kinematic Mapping ◽  
Noncircular Gears

The synthesis of a kinematic trajectory traversed by an output link (planet gear) and posture of a planetary gear train with noncircular gears can be divided into two phases: dimensional synthesis of the open-chain 2R mechanism (planetary carrier) and optimization of the transmission ratio of noncircular gear pairs. According to kinematic mapping theory, more than one closed coupler trajectory can be obtained by five preset poses. Simultaneous consideration of the trajectory shape, posture, and gear ratio is difficult during planetary gear train synthesis. This work therefore proposes a new method for the synthesis of planetary gear train in which different path segments in different trajectories are selected and a group of same-type 2R mechanisms is employed to pass through them in order to rebuild a new, closed trajectory. Subsequently, the transmission ratio of noncircular gear pairs can be determined using the relative angular displacement of the 2R mechanism. To improve the roundness of the pitch curves of noncircular gears, two optimization steps are implemented using a genetic algorithm without alternating the data points of the requisite open trajectories. For example, a mechanism for rice pot seedling transplanting is obtained by using the method.

scholarly journals Design of Vegetable Pot Seedling Pick-up Mechanism with Planetary Gear Train

2020 ◽  
Vol 33 (1) ◽  
Author(s):  
Zhipeng Tong ◽  
Gaohong Yu ◽  
Xiong Zhao ◽  
Pengfei Liu ◽  
Bingliang Ye
Keyword(s):  
Design Method ◽  
Planetary Gear ◽  
Gear Train ◽  
Dimensional Synthesis ◽  
Planetary Gear Train ◽  
Key Points ◽  
Physical Prototype ◽  
Noncircular Gears ◽  
Pitch Curve ◽  
Parameter Values

Abstract It has been challenging to design seedling pick-up mechanism based on given key points and trajectories, because it involves dimensional synthesis and rod length optimization. In this paper, the dimensional synthesis of seedling pick-up mechanism with planetary gear train was studied based on the data of given key points and the trajectory of the endpoint of seedling pick-up mechanism. Given the positions and orientations requirements of the five key points, the study first conducted a dimensional synthesis of the linkage size and center of rotation. The next steps were to select a reasonable solution and optimize the data values based on the ideal seedling trajectory. The link motion was driven by the planetary gear train of the two-stage gear. Four pitch curves of noncircular gears were obtained by calculating and distributing the transmission ratio according to the data. For the pitch curve with two convex points, the tooth profile design method of incomplete noncircular gear was applied. The seedling pick-up mechanism was tested by a virtual prototype and a physical prototype designed with the obtained parameter values. The results were consistent with the theoretical design requirements, confirming that the mechanism meets the expected requirements for picking seedlings up. This paper presents a new design method of vegetable pot seedling pick-up mechanism for an automatic vegetable transplanter.

Novel Gear Transmission Mechanism With Twice Unequal Amplitude Transmission Ratio

2019 ◽  
Vol 141 (9) ◽  
Author(s):  
Gaohong Yu ◽  
Zhipeng Tong ◽  
Liang Sun ◽  
Junhua Tong ◽  
Xiong Zhao
Keyword(s):  
Structural Characteristics ◽  
Angular Displacement ◽  
Planetary Gear ◽  
Gear Transmission ◽  
Transmission Mechanism ◽  
Gear Train ◽  
Transmission Ratio ◽  
Gear Pair ◽  
Pitch Curve ◽  
Gear Rack

The operation effectiveness of multi-bar transplanting mechanisms is low, and the specific changing law of the transmission ratio (the curve of the transmission ratio has twice unequal amplitude [TUA] fluctuation.), which is needed in vegetable pot seedling transplanting, is difficult to fulfill using a planetary gear train with noncircular gears and a single-planet carrier. To address this problem, we propose a noncircular gear pair that comprises an incomplete noncircular gear, rack, partial noncircular gear, and elliptical gear. The structural characteristics and the working principle of the TUA gear pair were analyzed. The pitch curve equation of the noncircular TUA gears was derived from the relationship of the angular displacement of the corresponding pitch curves. The influence of central angle α and eccentricity k on the shape of the pitch curve, angular displacement, and transmission ratio of the TUA gear pair was analyzed. The TUA gear pair was applied to a proposed vegetable seedling pickup mechanism (SPM) considering the design requirements. Finally, the feasibility of the new noncircular TUA gear transmission mechanism was verified by an SPM test.

A novel planar motion generation method based on the synthesis of planetary gear train with noncircular gears

2019 ◽  
Vol 33 (10) ◽  
pp. 4939-4949 ◽  
Author(s):  
Jun Ye ◽  
Xiong Zhao ◽  
Ying Wang ◽  
XinCheng Sun ◽  
JianNeng Chen ◽  
...  
Keyword(s):  
Planetary Gear ◽  
Gear Train ◽  
Planar Motion ◽  
Motion Generation ◽  
Planetary Gear Train ◽  
Noncircular Gears

Multi-Objective Optimization for the Efficiency and Weight of Helicopter Transmission Planetary Gear Train

2014 ◽  
Vol 635-637 ◽  
pp. 177-180
Author(s):  
Kang Huang ◽  
Xiao Hui Zhu ◽  
Xiang Chen ◽  
Gong Chuan Xia
Keyword(s):  
Planetary Gear ◽  
Optimization Method ◽  
Gear Train ◽  
Transmission Ratio ◽  
Design Parameters ◽  
Multi Objective Optimization ◽  
Planetary Gear Train ◽  
Multi Objective ◽  
Critical Design ◽  
Helicopter Transmission

A multi-objective optimization method for the optimization of the efficiency and weight of helicopter transmission planetary gear train was established. Taking the transmission ratio, efficiency weight, and reliability as critical design parameters, taking the conditions of the planetary gear train itself and the strength check constraint for the gear train as constraint functions, making the weight and efficiency of the planetary gear train asoptimization targets and using the Matlab function fgoalattain, a multi-objective optimization has been made. Comparison between the initial and the optimized results showed the success of the optimized planetary gear train in reducing the weight and increasing the efficiency.

Reliability sensitivity analysis of tooth modification on dynamic transmission error of helical planetary gears

2020 ◽  
Vol 234 (19) ◽  
pp. 3903-3918
Author(s):  
Zhang Jun ◽  
Tang Wei-min ◽  
Chen Qin ◽  
Chen Tao
Keyword(s):  
Quantitative Relationship ◽  
Planetary Gear ◽  
Transmission Error ◽  
Gear Train ◽  
Gear Pair ◽  
Tooth Contact Analysis ◽  
Planetary Gear Train ◽  
Dynamic Transmission Error ◽  
Tooth Modification ◽  
Meshing Characteristics

As one of the most influential factors leading to gear vibrations, transmission errors of the engaging gears must be controlled to achieve a desirable dynamic performance for a power transmission system. It is well known that tooth modification is an effective way to reduce the fluctuations of the transmission error of a gear pair. The challenge is determining how to establish a quantitative relationship between the tooth modification parameters and the transmission error fluctuations of a gear pair. The present study aims to reveal the sensitivity of the tooth modification parameters on the transmission error fluctuations of a helical planetary gear train in a wind turbine gearbox. For this purpose, a sophisticated parametric three-dimensional contact model that included the micro-geometries of the tooth modification is developed in the ROMAX® environment. Based on this model, a loaded tooth contact analysis is carried out to compute the meshing characteristics, such as the contact pressure and transmission error of each gear pair in the planetary gear train. With the obtained meshing characteristics, the tooth modification amounts of the engaging gears were determined using empirical formulas. These modification amounts are designated as the mean values of the samples generated by the central composite method. After repeating the loaded tooth contact analysis process for each generated sample, a quadratic polynomial function is derived using the response surface method to describe the quantitative relationship between the tooth modification parameters and the dynamic transmission error fluctuations. A large number of random samples are generated using a Monte Carlo method, and the corresponding dynamic transmission error fluctuations are determined with the aforementioned quadratic polynomial function. Based on these samples, a reliability sensitivity analysis is carried out to demonstrate the effects of the tooth modification parameters on the dynamic transmission error fluctuations of the helical planetary gear train.

Analysis on Transient Dynamic Load of Planetary Gear Pair

2014 ◽  
Vol 988 ◽  
pp. 353-358
Author(s):  
Xian Long Jiang ◽  
Suo Huai Zhang ◽  
Yan Xu Jia ◽  
Hao Zhang
Keyword(s):  
Finite Element ◽  
Planetary Gear ◽  
Element Model ◽  
Tooth Profile ◽  
Gear Train ◽  
Contact Theory ◽  
Gear Pair ◽  
Time Curve ◽  
Planetary Gear Train ◽  
Element Theory

The geometry of a precise involute NGW planetary gear train has been built by Solidworks, the overall finite element model of planetary gear train has been built in ANSYS Workbench. According to the non-linear finite element contact theory and the finite element theory, instantaneous state mesh of Planetary Gear Pair has been simulated dynamically. And the time curve of the maximum stress strain for planetary gear train and the stress law of the mesh for each gear in different tooth profile were obtained. The variation of stress in different tooth profile of mesh has been analyzed to improve the performance of the planetary gear and reliability to provide some theoretical guidance.

Dynamic Characteristics of Double Helical Planetary Gear Train With Tooth Friction

2015 ◽  
Author(s):  
Fengxia Lu ◽  
Rupeng Zhu ◽  
Haofei Wang ◽  
Heyun Bao ◽  
Miaomiao Li
Keyword(s):  
Degrees Of Freedom ◽  
Sliding Friction ◽  
Planetary Gear ◽  
Gear Train ◽  
Variable Step Size ◽  
Step Size ◽  
Planetary Gear Train ◽  
Gear Mesh ◽  
Meshing Stiffness ◽  
Nonlinear Dynamics Model

A new nonlinear dynamics model of the double helical planetary gear train with 44 degrees of freedom is developed, and the coupling effects of the sliding friction, time-varying meshing stiffness, gear backlashes, axial stagger as well as gear mesh errors, are taken into consideration. The solution of the differential governing equation of motion is solved by variable step-size Runge-Kutta numerical integration method. The influence of tooth friction on the periodic vibration and nonlinear vibration are investigated. The results show that tooth friction makes the system motion become stable by the effects of the periodic attractor under the specific meshing frequency and leads to the frequency delay for the bifurcation behavior and jump phenomenon in the system.

Specific Conditions of A I ¯ -Planetary Gear Train

2019 ◽  
pp. 27-30
Author(s):  
Kiril Arnaudov ◽  
Dimitar Petkov Karaivanov
Keyword(s):  
Planetary Gear ◽  
Gear Train ◽  
Planetary Gear Train
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