Epicyclic Gear Trains Research Articles

Study of Influence of Element Deformation and Manufacturing Errors of an Epicyclic Gear Train on the Load Distribution among Satellites

Study of Influence of Element Deformation and Manufacturing Errors of an Epicyclic Gear Train on the Load Distribution among Satellites

Kinematic and dynamic analysis of a planetary gear box in steady-state working regime

The paper presents a method for analysis of planetary gear boxes in order to calculate the speed and torque of the epicyclic gear trains elements. Based on these findings, the power flow within the gear box is determined. Additionally, the mechanical efficiency is estimated in order to assess the overall efficiency of the transmission.

Design, Load Analysis and Optimization of Epicyclic Gear Trains

Abstract: Mechanical power transmission systems rely heavily on Epicyclic gear trains, as their failure can compromise the entire system. Consequently, identifying and mitigating the causes of gear failure is crucial. Various gear failure modes, including bending pitting (contact stresses), failure (load failure), abrasive wear, and scoring, are discussed in literature by J.R. Davis(2005) [24], Khurmi & Gupta (2006) [23], and P. Kannaiah (2006) [21][22]. These failures are often linked to the loads acting on the gears. This research focuses on optimizing gear design to reduce gear load failure. Table 1 summarizes various research efforts on Epicyclic gear trains conducted by different authors. This study delves into the optimization of epicyclic gear trains in India to minimize load failure. The analysis focuses on optimizing the gear train through load analysis of the pinions, gears, and annulus, including the sun and planet gears. The goal is to determine the optimal load conditions for the gear train to function effectively without succumbing to load failure. Epicyclic Gear Trains are widely used in industry due to their numerous advantages, including high torque capacity, improved efficiency, relatively smaller size, lower weight, and a highly compact package. However, there has been no comprehensive study of their load-bearing performance with respect to various parameters such as rotational speed, material, and power. This research paper aims to fill this gap by investigating the load performance of epicyclic gear trains under different parameters such as loading conditions and rotational speeds. This process helps in identifying the optimized design of epicyclic gear trains, ensuring optimal performance and minimizing gear loads and choosing correct rotational speed. The primary objective of this research investigation is to optimize epicyclic gear trains through load analysis to prevent future load failures.

An effective modelling approach for multi-body dynamic analysis of epicyclic gear train of GTF considering both structural flexibility and mechanical interactions

In this paper, a new modelling approach is proposed for the dynamic investigation of epicyclic gear train, and the novelty of this work lies in consideration of both structural flexibility and mechanical interactions during the analysis procedure. The method is of capacity to directly present the dynamic results of the supporting structure for convenient practical engineering evaluation and reduce the dimension of the system reasonably with appropriate assumptions for better computational efficiency. Firstly, the mechanical interactions among components are discussed in detail, and the principle that the structural flexibility works is also explained at length. Secondly, taking the epicyclic gear train of the geared turbofan (GTF) engine; for example, the dynamic model of the system is then established based on the developed hybrid user-defined elements. For model validation, the governing equations of the system are also derived by the lumped mass method. Thirdly, with the same values of the parameters, the results of normal dynamic meshing force obtained by the proposed model are compared with the ones by the lumped mass model. It can be stated from the data that (1) the maximum relative error between the theoretical value and the average value calculated by the two models is 8.28%, (2) the gear mesh frequency obtained by the two models are sufficiently close to the theoretical value, and (3) the fluctuation trends of the dynamic force keep basically consistent with each other. In summary, the comparison presented clearly indicates that the proposed model is indeed reasonable, which provides a new way for dynamic investigation and structural redesign of a large epicyclic gear train. Finally, as a practical engineering application, the vibration result of the deformable supporting structure of the GTF gear train is also presented, which directly provides valuable reference for vibration monitoring, fault diagnosis and other engineering problems in practice.

Analysis of the Influence of Calculation Parameters on the Design of the Gearbox of a High-Power Wind Turbine

As wind turbine power requirements have evolved from the order of kilowatts (kWs) to the order of several megawatts (MWs), wind turbine components have been subjected to more demanding and critical operating conditions. The wind turbine must cope with higher wind loads due to larger blade sizes, which are also time-varying, and, ultimately, higher power levels. One of the challenges in the manufacture of high-power wind turbines lies in the gearbox and consists of achieving ever-greater power density without compromising efficiency, i.e., greater load capacity with lower weight (and production cost) and reduced power losses. Epicyclic geartrains are used to build the gearbox due to various advantages in relation to conventional gear systems, such as higher feasible gear ratios, higher efficiency, compactnesss, and lower weight. In this paper, several epicyclic geartrains with different structures will be analysed to reveal the influence that certain design parameters have on the size and weight of the gearbox components in the selected model and, therefore, of the gearbox itself. For this purpose, the theoretical model of the gearbox will be planned and the influence of the calculation parameters on the gearbox design will be analyzed following ISO 6336. Special emphasis is placed on the influence of the material used; the modulus and tooth width on the size and weight of the gearbox will be observed. Critical stresses are also calculated. The goal is to prepare the theoretical basis for an optimization process subject to geometric, kinematic, and dynamic constraints that will result in a gearbox as compact, energy-dense, and light as possible without compromising the service life of the components.

Determination of Power Flow and Calculation of Transmission Efficiency for 2K-H Closed Epicyclic Gear Train

Determination of Power Flow and Calculation of Transmission Efficiency for 2K-H Closed Epicyclic Gear Train

The HA4M dataset: Multi-Modal Monitoring of an assembly task for Human Action recognition in Manufacturing

This paper introduces the Human Action Multi-Modal Monitoring in Manufacturing (HA4M) dataset, a collection of multi-modal data relative to actions performed by different subjects building an Epicyclic Gear Train (EGT). In particular, 41 subjects executed several trials of the assembly task, which consists of 12 actions. Data were collected in a laboratory scenario using a Microsoft® Azure Kinect which integrates a depth camera, an RGB camera, and InfraRed (IR) emitters. To the best of authors’ knowledge, the HA4M dataset is the first multi-modal dataset about an assembly task containing six types of data: RGB images, Depth maps, IR images, RGB-to-Depth-Aligned images, Point Clouds and Skeleton data. These data represent a good foundation to develop and test advanced action recognition systems in several fields, including Computer Vision and Machine Learning, and application domains such as smart manufacturing and human-robot collaboration.

Approximate Motion Generation of an Epicyclic Gear Train With Noncircular Gears Based on Optimization–Homotopy Algorithm

Abstract This study aims to make approximate motion generation that has multiple solutions to facilitate the selection of the best mechanism parameters. Therefore, an approximate synthesis method for an epicyclic gear train (EGT) with noncircular gears based on optimization–homotopy algorithm is proposed in this paper. First, the multipose synthesis objective function of a simplified model of EGT (planar RR dyad) is established. The approximate motion generation is transformed into the extremum problem of multivariate function, and a variable is introduced to expand the solution space. A homotopy algorithm is used to solve the gradient equation of the objective function to obtain the finite range solution domain. Second, the feasible solution domain of EGT is obtained by identifying the total rotation of revolute joints of the RR dyad, and a mechanism error evaluation index is established. In accordance with actual constraints, the most suitable solution is selected in the feasible solution domain, and the relative angular displacement relationship of the selected RR dyad is used to determine the transmission ratio and pitch curve of noncircular gears to realize the design of an EGT. Lastly, a design example is provided to illustrate the feasibility of the method.

A novel variable stiffness actuator based on a rocker-linked epicyclic gear train

• A novel variable stiffness actuator based on a rocker-linked epicyclic gear train is proposed. • The simultaneous relocations of the pivot and torsion spring permit a wide-range stiffness adjustment. • The energy efficiency is improved by introducing a linear guide and a cam follower. • A dynamic single-neuron adaptive PID controller is presented for trajectory tracking. This paper presents a novel variable stiffness actuator based on a rocker-linked epicyclic gear train (REGT-VSA). The stiffness adjustment principle of the actuator is to change the lever ratio of force by converting the differential motion of the planetary gear train into the linear motion of the elastic element. The unique design of the rocker-linked epicyclic gear train ensures the compactness of structure and the accuracy of transmission. The simultaneous relocations of the pivot and torsion spring permit a wide-range stiffness adjustment. By introducing a linear guide and a cam follower, the internal friction is reduced, and the energy efficiency is improved. A prototype and its trajectory tracking controller are developed to evaluate the performance of REGT-VSA. An exponential function is used to train the neuron proportion coefficient of the conventional single-neuron adaptive proportional-integral-derivative (PID) controller to compensate for the position error in real time, thus creating the dynamic single-neuron adaptive PID controller. The stiffness identification and trajectory tracking experiments under different conditions prove the feasibility of the actuator and the proposed algorithm.

The singular value decomposition method of improved incidence matrix for isomorphism identification of epicyclic gear trains

Abstract. The epicyclic gear train (EGT) is an advanced gear transmission mechanism, which is widely applied in drive systems. It is of great significance to eliminate the same structure in the type synthesis of EGTs. In this paper, an isomorphism identification method of EGTs based on the singular value decomposition of improved incidence matrix is proposed. Firstly, the improved incidence matrix is used to describe the structure of EGTs. Then, the degree sequence of links and kinematic pairs can be extracted and used as a basic information for preliminary screening. The improved incidence matrix can effectively distinguish multiple joints. Next, the topological connection relationship between the links and the kinematic pairs is extracted by the singular value decomposition of the matrix, which is used as the final value for isomorphism identification of EGTs. Finally, the effectiveness of this method is verified through a lot of examples.

An attachment with the hand pump to lift water without any external source

Without proper irrigation to farm, sustainability on agriculture is not possible; irrigation helps to grow the crop. There are numbers of irrigation methods available to supply water to the crop. Maximum percentages of people in rural areas are depending on agriculture. They are using traditional methods for their irrigation. So it is required to provide them better training towards technology based irrigation. The developed and technology based irrigation method provides maximum output for agriculture, maximum output from the agriculture provides better sustainability to farmers. In this work a new technology based irrigation system has been presented. It is required to attach this system with the hand pump. The system consists of an epicyclic gear train arrangement, simple gear train arrangement, fly wheel and handle. All these arrangements are provided on a frame. The weight and cost of the developed system is very less. So poor farmers can attach this system with their hand pump to lift water for irrigation. The designed system works by the concept of Mechanical Advantage (MA), Velocity Ratio (VR) and energy storage. Irrigation by this designed method does not require any external sources like petrol, diesel and kerosene operated pump, and the designed model is environment friendly. Only a small amount installation cost is required to attach the designed system with the hand pump.

Vibration analysis of planetary gearbox using empirical mode decomposition and automatic fault prediction using artificial neural network

The planetary gearbox works on an epicyclic gear train consisting of sun gear meshed with planets gears and ring gear. It got advantages due to its large torque to weight ratio and reduced vibrations. It is mostly employed in analog clocks, automobile automatic gearbox, Lathe machines, and other heavy industries. Therefore, it was imperative to analyze the various faults occurring in a gearbox. Furthermore, come up with a method so that failures can be avoided at the early stage. It was also a reason why it became the field of intensive research. Moreover, the technology of neural networks emerged recently, where machine learning models are trained to detect uneven vibrations on their own. This attracted many researchers to perform the study to devise their own methods of prediction. The central concept of fault prediction by the neural network without human beings’ interference inspired this study. Most industries always wanted to know if their operation line is working fine or not. In this study, an attempt was made to apply the method of deep learning on one of the most critical gearboxes because of its components and functionality. A significant part of the study also involved filtering the vibration data obtained while testing. Comparative analysis of the variation of the peak of acceleration was performed for healthy and faulty conditions.

Mechanical Efficiency of HMCVT under Steady-State Conditions

Hydromechanical continuously variable transmission (HMCVT) technology has been widely used due to its advantages of ride comfort and fuel economy. The relatively uniform efficiency expression of HMCVT is obtained by studying torque and transmission ratios to reveal steady-state characteristics and predict the output torque. Mathematical models of torque ratios are derived by analyzing the HMCVT system power flow and calculating the equivalent meshing power of epicyclic gear train and efficiency for the hydraulic system. The relationship between mechanical system transmission and hydraulic system parameters is established using the torque ratios, and a mechanical system demanding surface is proposed. Two numerical examples of the HMCVT system with single and dual variable units are demonstrated to establish an effective and convenient method. The method is validated through a physical prototype TA1-02 test.

Revelation of metamorphic phenomenon through the equivalent mechanisms and development of the novel metamorphic epicyclic gear trains

Epicyclic gear train, a typical higher pair mechanism with one-wheel axis that revolves around another fixed axis, has been widely used in mechanism design. However, applying the metamorphic mechanisms to the epicyclic gear trains remains a challenge. This paper analyses the metamorphic phenomenon of epicyclic gear trains using the equivalent mechanism approach and presents for the first time a set of novel metamorphic epicyclic gear trains with variable motion branches and changed configurations. Three 5-bar equivalent mechanisms of typical epicyclic gear trains and their equivalent geometrical relationships are introduced based on the instantaneous screw axes of the gear pairs. First- and second-order kinematic models of the equivalent mechanisms are established to obtain motion branches and their corresponding constraint conditions. With the equivalent geometrical relationship, the configurations and the motion branches of the epicyclic gear train are identified, and the constraint conditions are obtained. A set of novel metamorphic epicyclic gear trains are therefore designed by implementing the metamorphosis technique that can realize the configuration transformation of an epicyclic gear train under constraint conditions. A metamorphic epicyclic bevel gear clamping mechanism is further designed as an example to demonstrate the application of the metamorphic epicyclic gear mechanisms.

A Novel Loaded Tooth Contact Analysis Procedure With Application to Internal–External Straight Bevel Gear Mesh in a Pericyclic Drive

Abstract A comprehensive numerical loaded tooth contact analysis (LTCA) model is proposed for straight bevel gears that exhibit large number of teeth in contact, well beyond the involute line of action limits. This kind of contact is observed when the meshing gears have conformal surfaces, as in a pericyclic mechanical transmission, and is traditionally analyzed using finite element simulations. The pericyclic drive is kinematically similar to an epicyclic bevel gear train and is characterized by load sharing over large number of teeth in an internal–external bevel gear mesh, large shaft angles (175–178 deg), nutational gear motion, and high reduction ratio. The contact region spreads over a large area on the gear tooth flank due to high contacting surface conformity. Thus, a thick plate finite strip method (FSM) was utilized to accurately calculate the gear tooth bending deflection. Based on the tooth deformation calculation model and accounting for initial surface separation, a variational framework is developed to simultaneously solve for load distribution and gear tooth deformation. This is followed by calculation of contact stress, bending stress, mesh stiffness, and transmission error. The results demonstrate the high-power density capabilities of the pericyclic drive and potential for gear noise reduction. The model developed herein is applied with real gear tooth surfaces, as well.

Comparative study between modified path matrix approach, modified gradient method and Bocher’s technique to detect isomorphism in EGTs

The Structural synthesis and topological analysis of Epicyclic gear trains (EGTs) have been great research area for checking isomorphic properties of mechanisms since few decades. In this paper, comparative analysis was done between three methods as Modified path matrix approach (MPM), Modified gradient method (MGM) and Bocher’s Technique (BT) for checking isomorphism in EGTs and its inversions. These methods have computed on the basis of reliability of results, computational application & structural properties for theirs merits and demerits by using MATLAB software. The methods have been compared with examples of 4-link EGTs and 6-link EGTs One-DOF. All examples have found satisfactory results on the basis of literature.

Generation of one- DOF epicyclic gear trains with up to eight links

The generation of epicyclic gear trains (EGTs) by application of graph theory has a major focus by researchers to avoid duplicity of mechanisms as well as topological structural and synthesis analysis. This paper presents the generation of EGTs with one degree of freedom up to eight links. The method has been formulated on the basis of conventional graphs, the graphs converted into adjacency matrices and then, obtained wiener number for structural synthesis and isomorphic property. The results obtained by this method have been fully satisfied with references

Equivalent Circuit Method for Isomorphism Identification of Complex Epicyclic Gear Train

Equivalent Circuit Method for Isomorphism Identification of Complex Epicyclic Gear Train

The Mechanical Efficiency of Harmonic Drives: A Simplified Model

Abstract Harmonic drives are widely used devices in robotic and space applications. As for any device transmitting motion, its mechanical efficiency is one of the main concerns for the designer. In this paper, it is proposed a new model to estimate this significant feature. The proposed approach makes use of the kinematic correspondence between the harmonic drive and an epicyclic gear train. Although the authors introduced simple approximations to describe the complex tribological phenomena during harmonic drive teeth meshing, the numerical results match the trend of experimental evidence. In particular, assuming the harmonic drive working at the rated torque, the plots of the mechanical efficiency versus different parameters such as temperature and angular speed have been simulated.

PRIMENA EPICIKLIČNIH ZUPČASTIH PRENOSNIKA SA NEOKRUGLIM ZUPČANICIMA ZA POVEĆANJE STEPENA KORISNOSTI SUS MOTORA

Povećanje efikasnosti SUS motora je tema mnogih diskusija u struci, i jedan pristup koji se sreće je modifikacija termodinamičkog radnog ciklusa motora kojom se realni cilkus približava idealnom. Ovaj rad pokušava to da postigne izmenom kinematike klipnog mehanizma uvođenjem epicikličnih neokruglih zupčanika između kolenastog vratila i zamajca. Dodatak neokruglih zupčanika menja radni ciklus uvođenjem prisilnog perioda mirovanja klipa tokom ključnih momenata tokom ciklusa. Moguća rešenja oblika zupčanika izračunata su na osnovu prenosnog odnosa izraženog poznatom periodičnom funkcijom. Konačni rezultat je epiciklični prenosnik sa neokruglim zupčanicima sa primetnim uticajem na kinematiku klipnog mehanizma, što za posledicu ima povećanje efikasnosti motora.