Modeling of an Automotive Planetary Gear Set Based on Karnopp Model for Clutch Friction

2003 ◽  
Author(s):  
Josˇko Deur ◽  
Jahan Asgari ◽  
Davor Hrovat
Keyword(s):  
Planetary Gear ◽  
Friction Model ◽  
Modeling Method ◽  
Automatic Transmissions ◽  
Straight Line ◽  
Planetary Gear Sets ◽  
Simulation Results ◽  
Simulation Time

Planetary gear sets of automotive automatic transmissions include several hydraulic and one-way clutches. Clutch friction is traditionally described by the generalized, Stribeck, speed-dependent static function approximated by a steep straight line in the zero-speed region (so-called classical friction model). Another approach based on the Karnopp clutch friction model is proposed in this paper. Simulation results for park/reverse engagement and 1–2 upshift shows that the proposed gear set modeling method compared to the classical friction modelbased method yields significant improvement with respect to simulation time, as well as accuracy.

Matrix-Based Operation Method for Detecting Structural Isomorphism of Planetary Gear Train Structures

2019 ◽  
Vol 142 (6) ◽  
Author(s):  
Xiangyang Xu ◽  
Hanqiao Sun ◽  
Yanfang Liu ◽  
Peng Dong
Keyword(s):  
Planetary Gear ◽  
Gear Train ◽  
Synthesis Algorithm ◽  
Automatic Transmissions ◽  
Detection Approach ◽  
Planetary Gear Sets ◽  
Transmission Structure ◽  
Structural Isomorphism ◽  
Hybrid Configuration ◽  
Isomorphic Structure

Abstract Planetary gear sets (PGSs) have been widely used in automatic transmissions (AT) and dedicated hybrid transmissions (DHTs). In this paper, a novel isomorphic detection method for planetary gear transmission structure is proposed based on matrix operation. The isomorphic detection process includes two main parts. In the first part, various components of the transmission structure are classified. In the second part, isomorphic structures of the numerous structures are detected. Through the application of the proposed detection approach, the structures obtained by different synthesis algorithms can be greatly reduced. Furthermore, by the analysis and transformation of the hybrid configuration to conventional transmission configuration, the scope of use of the algorithm can be expanded through the method. The proposed detection approach is capable of automatically detecting the isomorphic structure of the potential structures obtained by synthesis algorithm.

Axial Thrust Force of Compound Planetary Spur Gear Set

2011 ◽  
Vol 133 (9) ◽  
Author(s):  
Yang Fuchun ◽  
Zhou Jutao ◽  
Zhou Xiaojun ◽  
Zhu Hongqing
Keyword(s):  
Thrust Force ◽  
Planetary Gear ◽  
Spur Gear ◽  
Axial Thrust ◽  
Aerospace Applications ◽  
Automatic Transmissions ◽  
Higher Power ◽  
Planetary Gear Sets ◽  
Torsional Pendulum ◽  
Theory Calculation

Planetary gears are widely used in automotive and aerospace applications. Traditionally, automatic transmissions have four forward speeds, which can be achieved by using two planes of single pinion (sun-pinion-ring) planetary gear sets. Recently, there is a trend that transmissions have more than five forward speeds, which make compound planetary gear sets with two pinions (ring- or sun-pinion1-pinion2-ring) becoming common. Due to demands for higher power density and compactness, needle bearings are often used in these gear sets. There are significant axial thrust forces between the pinions and the carrier, which could lead to excessive wear of thrust faces and deterioration of bearing system performance. In this paper, we analyzed generation mechanism of axial thrust force in compound planetary spur gear set and calculated the axial thrust force. It was shown that axial thrust force always exists because of the torsional pendulum torque acting on the long planet. Experimental test for a compound planetary spur gear was taken to study axial thrust force and validate the theory calculation.

Optimization of RANS Solver Simulation Setup for Propeller Open Water Performance Prediction

2015 ◽  
Author(s):  
Mohammed Islam ◽  
Fatima Jahra ◽  
Michael Doucet
Keyword(s):  
Domain Size ◽  
Open Water ◽  
Fractional Factorial ◽  
Navier Stokes ◽  
Calm Water ◽  
Simulation Results ◽  
Open Water Performance ◽  
Thrust And Torque ◽  
Simulation Time ◽  
Fixed Pitch

Mesh and domain optimization strategies for a RANS solver to accurately estimate the open water propulsive characteristics of fixed pitch propellers are proposed based on examining the effect of different mesh and computation domain parameters. The optimized mesh and domain size parameters were selected using Design of Experiments (DoE) methods enabling simulations to be carried out in a limited memory environment, and in a timely manner; without compromising the accuracy of results. A Reynolds-Averaged Navier Stokes solver is used to predict the propulsive performance of a fixed pitch propeller. The predicted thrust and torque for the propeller were compared to the corresponding measurements. A total of six meshing parameters were selected that could affect the computational results of propeller open water performance. A two-level fractional factorial design was used to screen out parameters that do not significantly contribute to explaining the dependent parameters: namely simulation time, propeller thrust and propeller torque. A total of 32 simulations were carried out only to find out that the selected six meshing parameters were significant in defining the response parameters. Optimum values of each of the input parameters were obtained for the DOE technique and additional simulations were run with those parameters. The simulation results were validated using open water experimental results of the same propeller. It was found that with the optimized meshing arrangement, the propeller opens simulation time was reduced by at least a factor of 6 as compared to the generally popular meshing arrangement. Also, the accuracy of propulsive characteristics was improved by up to 50% as compared to published simulation results. The methodologies presented in this paper can be similarly applied to other simulations such as calm water ship resistance, ship propulsion to systematically derive the optimized meshing arrangement for simulations with minimal simulation time and maximum accuracy. This investigation was carried out using STAR-CCM+, a commercial CFD package; however the findings can be applied to any RANS solver.

Development of 2 Stage CVT Shift Control Algorithm to Reduce Torque Variation During 1-2 Upshift of Planetary Gear

2012 ◽  
Author(s):  
Jeongman Park ◽  
Sunghyun Ahn ◽  
Oheun Kwon ◽  
Youngho Jun ◽  
Minhyo Kim ◽  
...  
Keyword(s):  
Control Algorithm ◽  
Planetary Gear ◽  
Gear Ratio ◽  
Shift Quality ◽  
Response Characteristics ◽  
Shift Control ◽  
Variable Transmission ◽  
Vehicle Simulator ◽  
Simulation Results ◽  
Fuzzy Control Algorithm

In this paper, a 2 stage continuously variable transmission (CVT) shift control algorithm is proposed for the 1–2 upshift of the planetary gear to achieve the shift quality. A fuzzy control algorithm is designed considering the relatively slower response characteristics of CVT. In order to evaluate the performance of the control algorithm, a 2 stage CVT vehicle simulator is developed including a dynamic model of the CVT powertrain. From the simulation results, it is found that CVT gear ratio changes faster in the inertia phase and remains constant after the inertia phase of the planetary gear shift, which provides the reduced torque variation by the proposed control algorithm.

The Research on Natural Characteristic and Eigensensitivity of Ravingneaux Compound Planetary Gear Sets

2013 ◽  
Vol 446-447 ◽  
pp. 590-596
Author(s):  
Bo Qian ◽  
Shi Jing Wu
Keyword(s):  
Natural Frequency ◽  
Planetary Gear ◽  
Torsional Stiffness ◽  
Ring Gear ◽  
Vibration Model ◽  
Planetary Gear Sets ◽  
Planet Gear ◽  
Natural Characteristic ◽  
Gear Ring ◽  
The Moment

The dynamic model of Ravingneaux compound planetary gear sets has been built. Then the Natural frequency and vibration model have been solved in the Ravingneaux compound planetary gear sets. The eigensensitivity to parameters have been researched based on the dynamical model. The varying trend of natural frequency according to the varying of parameters have been researched, which include gear mass (sun gear, ring gear , or planet gear), the moment of inertia of gears, the support stiffness , the torsional stiffness.

Optimal Synthesis and Analysis of a New Leg Mechanism: The Planetary Gear Leg

1992 ◽  
Author(s):  
Ning-Xin Chen ◽  
Shin-Ming Song
Keyword(s):  
Planetary Gear ◽  
Optimization Method ◽  
Maximum Deviation ◽  
Walking Machine ◽  
Straight Line ◽  
Force Moment ◽  
Good Energy ◽  
Line Trajectory ◽  
Leg Design ◽  
Straight Line Trajectory

Abstract The leg mechanism of a walking machine has a strong influence on the performance of the machine. A successful leg mechanism should be energy efficient, compact in size, strong and simple. In order to achieve good energy efficiency, a walking machine leg should be able to generate an exact or approximate straight line at the foot with only one driving actuator. This paper deals with the synthesis and analysis of a new leg mechanism — the planetary gear leg mechanism. Four types of planetary gear legs are studied. By the SUMT optimization method, a 20 inch tall leg is able to generate an approximate straight line trajectory with a maximum deviation of 0.12805 inches in a 20 inch stroke. The direct and inverse kinematics and velocities of the legs are analyzed. Also, the distribution of actuator force/moment during walking are studied. The results show that this leg design has great potential to be used as a practical walking machine leg.

Mechanical Structural Interference Detection for Dedicated Hybrid Transmissions

2021 ◽  
Vol 143 (9) ◽  
Author(s):  
Hanqiao Sun ◽  
Xiangyang Xu ◽  
Yanfang Liu ◽  
Peng Dong ◽  
Shuhan Wang ◽  
...  
Keyword(s):  
Graph Theory ◽  
Graph Model ◽  
Planetary Gear ◽  
Modeling Method ◽  
Structural Synthesis ◽  
Original Graph ◽  
Power Sources ◽  
Detection Approach ◽  
Hybrid Transmission ◽  
Planetary Gear System

Abstract Planetary gear set (PGS) has been one of the best components to constitute a transmission configuration, including the dedicated hybrid transmission (DHT). Using different synthesis approaches, the DHT configurations can be obtained through algorithms. However, different synthesis results correspond to different connection states of the planetary gear system. There are a certain number of results that violate the motion requirements of the mechanical principal need to be detected and removed. Therefore, this paper presents a novel modeling method to systematically remove the interference structures, with graph theory in structural synthesis. Based on the original graph theory, this paper proposes an equivalent replacement modeling method to convert the motor graph model into a brake-like graph model. Based on the conversion, avoid the appearance of the hanging points in the graph model. By applying the proposed approach, a DHT structure proves the feasibility of the method. The proposed detection approach can systematically detect all the PGS-based transmission with multi-PGSs, multi-shifting elements, and multi-power sources.

An Analytical and Numerical Investigation of Modulation Sidebands of a Planetary Gear Under Fluctuated External Torque

2018 ◽  
Author(s):  
Yunbo Yuan ◽  
Wei Liu ◽  
Yahui Chen ◽  
Donghua Wang
Keyword(s):  
Planetary Gear ◽  
Transmission Error ◽  
Operating Conditions ◽  
Radial Acceleration ◽  
External Torque ◽  
Gear Mesh ◽  
Planetary Gear Sets ◽  
Static Transmission Error ◽  
Frequency Modulations ◽  
Mesh Phasing

Certain operating conditions such as fluctuation of the external torque to planetary gear sets can cause additional sidebands. In this paper, a mathematical model is proposed to investigate the modulation mechanisms due to a fluctuated external torque (FET), and the combined influence of such an external torque and manufacturing errors (ME) on modulation sidebands. Gear mesh interface excitations, namely gear static transmission error excitations and time-varying gear mesh stiffness, are defined in Fourier series forms. Amplitude and frequency modulations are demonstrated separately. The predicted dynamic gear mesh force spectra and radial acceleration spectra at a fixed position on ring gear are both shown to exhibit well-defined modulation sidebands. Comparing with sidebands caused by ME, more complex sidebands appear when taking both FET and ME into account. An obvious intermodulation is found around the fundamental gear mesh frequency between the FET and ME in the form of frequency modulations, however, no intermodulation in the form of amplitude modulations. Additionally, the results indicate that some of the sidebands are cancelled out in radial acceleration spectra mainly due to the effect of planet mesh phasing, especially when only amplitude modulations are present.

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