Dynamic Analysis of a Geared Infinitely Variable Transmission

2016 ◽  
Vol 12 (3) ◽  
Author(s):  
X. F. Wang ◽  
Z. R. Li ◽  
W. D. Zhu
Keyword(s):  
Dynamic Analysis ◽  
Speed Ratio ◽  
Force Analysis ◽  
Maximum Torque ◽  
Input Shaft ◽  
Continuous Output ◽  
Input Side ◽  
Variable Transmission ◽  
Infinitely Variable Transmission ◽  
Output Side

Dynamic analysis of a geared infinitely variable transmission (IVT) that can generate a continuous output-to-input speed ratio from zero to a certain value is studied for vehicle and wind turbine applications. With the IVT considered as a multirigid-body system, the Lagrangian approach is used to analyze its speeds and accelerations, and the Newtonian approach is used to conduct force analysis of each part of the IVT. Instantaneous input and output speeds and accelerations of the IVT have variations in one rotation of its input shaft. This work shows that the instantaneous input speed has less variation than the instantaneous output speed when the inertia on the input side is larger than that on the output side and vice versa. The maximum torque on the output shaft that is a critical part of the IVT increases with the input speed.

Dynamic Analysis of a Novel Geared Infinitely Variable Transmission

2014 ◽  
Author(s):  
Z. R. Li ◽  
X. F. Wang ◽  
W. D. Zhu
Keyword(s):  
Dynamic Analysis ◽  
Wind Turbine ◽  
Speed Ratio ◽  
Lagrangian Dynamics ◽  
Input And Output ◽  
Newtonian Dynamics ◽  
Continuous Output ◽  
Variable Transmission ◽  
Infinitely Variable Transmission ◽  
Crank Length

A novel geared infinitely variable transmission (IVT) that can generate a continuous output-to-input speed ratio from zero to a certain value is studied for vehicle and wind turbine applications. The principle of changing the output-to-input speed ratio is to use a crank-slider mechanism; the output-to-input speed ratio is controlled by adjusting the crank length. Since the crank-slider mechanism can lead to relatively large variation of the output-to-input speed ratio in one rotation of the crank, the instantaneous input and output speeds and accelerations have variations and the corresponding forces exerted on each part of the IVT can have obvious changes in one rotation of the crank. Since forces on some parts of the IVT are critical and can cause failure of the IVT, a dynamic analysis of the IVT is necessary to simulate the input and output speeds and accelerations. A method that combines Lagrangian dynamics and Newtonian dynamics is developed in this work to analyze the motion of the IVT. The dynamic analysis results can be used to evaluate the design of the IVT.

Design, Modeling, and Simulation of a Geared Infinitely Variable Transmission

2014 ◽  
Vol 136 (7) ◽  
Author(s):  
X. F. Wang ◽  
W. D. Zhu
Keyword(s):  
Planetary Gear ◽  
Speed Ratio ◽  
Start Up ◽  
Continuous Output ◽  
Direction Control ◽  
Variable Transmission ◽  
Infinitely Variable Transmission ◽  
Planetary Gear Sets ◽  
Working Principle ◽  
Crank Length

An infinitely variable transmission (IVT) to provide a continuous output-to-input speed ratio from zero to a certain value is designed, and its working principle is illustrated. It is a geared IVT (GIVT), since its function to achieve the continuously varied speed ratio is implemented by gears. Crank-slider systems are used in the GIVT; the output-to-input speed ratio is changed with the crank length. Racks and pinions, whose motion is controlled by planetary gear sets, are used to change the crank length when the cranks rotate. One-way bearings are used to rectify output speeds from different crank-slider systems to obtain the output speed of the GIVT. Since the crank-slider systems can introduce variations of the instantaneous speed ratio, a pair of noncircular gears is designed to minimize the variations. A direction control system is also designed for the GIVT using planetary gear sets. Finally, a vehicle start-up simulation and a wind turbine simulation to maintain a constant generator speed are developed based on a GIVT module in the Matlab Simulink environment.

Infinitely Variable Transmission of Racheting Drive Type Based on One-Way Clutches

2004 ◽  
Vol 126 (4) ◽  
pp. 673-682 ◽  
Author(s):  
F. G. Benitez ◽  
J. M. Madrigal ◽  
J. M. del Castillo
Keyword(s):  
Numerical Simulation ◽  
Dynamic Analysis ◽  
Numerical Simulations ◽  
Mechanical Efficiency ◽  
Testing Equipment ◽  
Epicyclic Gear ◽  
The Family ◽  
Variable Transmission ◽  
Infinitely Variable Transmission ◽  
Oscillatory Character

An infinitely variable transmission (IVT), based on the use of one-way action clutches, belonging to the family of ratcheting drives is described. The mechanical foundations and numerical simulations carried out along this research envisage a plausible approach to its use as gear-box in general mechanical industry and its prospective use in automobiles and self-propelled vehicles. The system includes one-way clutches—free wheels or overrunning clutches—and two epicyclic gear systems. The output velocity, with oscillatory character, common to the ratcheting drives systems, presents a period similar to that produced by alternative combustion motors, making this transmission compatible with automobile applications. The variation of the transmission is linear in all the working range. The kinematics operating principles behind this IVT is described followed by a numerical simulation of the dynamic analysis. A prototype has been constructed and tested to assess its mechanical efficiency for different reduction ratios. The efficiency values predicted by theory agree with those experimentally obtained on a bench-rig testing equipment.

Contact Stress Reduction Mechanisms for the CAM-Based Infinitely Variable Transmission

2007 ◽  
Author(s):  
Derek F. Lahr ◽  
Dennis W. Hong
Keyword(s):  
Contact Stress ◽  
Stress Reduction ◽  
Kinematic Model ◽  
Three Dimensional ◽  
Speed Ratio ◽  
Cam Mechanism ◽  
Expected Performance ◽  
Differential Mechanism ◽  
Variable Transmission ◽  
Infinitely Variable Transmission

The Cam-based Infinitely Variable Transmission (IVT) is a new type of ratcheting IVT based on a three dimensional cam and follower system which provides unique characteristics such as generating specific functional speed ratio outputs including dwells, for a constant velocity input. This paper presents several mechanisms and design approaches used to improve the torque and speed capacity of this unique transmission. A compact, lightweight, and capable differential mechanism based on a cord and pulley system is developed to double the number of followers in contact with the cam at any time, thereby reducing the contact stress between the followers and the cam surface considerably. A kinematic model governing the motion of this differential is developed and a few experimental results from the prototype are presented, showing an overall increase in performance including a smooth output, a wide gear range, and the ability to shift under load. Plans for future improvements to the design, including an inverted external cam mechanism, is also presented along with the expected performance gains.

Design of a Series-Type Independently Controllable Transmission Mechanism

2012 ◽  
Author(s):  
Guan-Shyong Hwang ◽  
Der-Min Tsay ◽  
Jao-Hwa Kuang ◽  
Tzuen-Lih Chern ◽  
Tsu-Chi Kuo
Keyword(s):  
Angular Velocity ◽  
Planetary Gear ◽  
Transmission Mechanism ◽  
Alternative Form ◽  
Input Shaft ◽  
Planetary Gear Trains ◽  
Variable Transmission ◽  
Infinitely Variable Transmission ◽  
Gear Trains ◽  
Series Type

This study proposes a design of transmission mechanism which is referred to as a series-type independently controllable transmission (ICT). The series-type ICT is an alternative form of the parallel-types proposed in the former researches. The series-type ICT can serve as a continuously or an infinitely variable transmission mechanism, and it can also produce a required angular output velocity that can be independently manipulated by a controller and not affected by the angular velocity of the input shaft. The series-type ICT mechanism is composed of two planetary gear trains and two transmission-connecting members. Kinematic and dynamic characteristics of the ICT mechanism are analyzed and their analytical equations are derived for application in this study.

Analysis of a New Form of Intrinsically Automatic Continuously Variable Transmission

2010 ◽  
Author(s):  
Timothy Cyders ◽  
Robert L. Williams
Keyword(s):  
Power Transmission ◽  
Mechanical Design ◽  
Peak Torque ◽  
Continuously Variable Transmission ◽  
Speed Ratio ◽  
Input Shaft ◽  
Positive Displacement ◽  
Variable Transmission ◽  
System Output ◽  
Human Powered

Effective continuously variable transmission (CVT) designs have been sought after for many years as their integration into many different mechanical systems can give many advantages over a discrete transmission system. Currently, CVTs are becoming popular for applications from automotive power transmission to wind power generation. Most CVT technologies, however, are friction- or hydraulic-based designs limited by both performance and system characteristics. This paper will evaluate a new, patented form of purely mechanical, intrinsically automatic CVT which is not based on belts, pulleys, gears or hydraulics. This new transmission is based on a deformable four-bar design incorporating a one-way clutch for positive displacement of the output. As torque demand on the system output is varied, the output’s displacement varies inversely to maintain a constant peak torque on the input shaft. The end result of this behavior is a possible instantaneous variation of speed ratio over an extreme range with a lightweight, simple mechanical design. This paper provides an analysis of the mechanism and its performance, as well as simulation results incorporating real-world measurement of system output into several different mechanical applications: a human-powered vehicle, an automobile and a centrifugal pump.

Synthesis and Analysis of a Parallel-Type Independently Controllable Transmission Mechanism

2016 ◽  
Vol 8 (4) ◽  
Author(s):  
Guan-Shong Hwang ◽  
Wei-Hsiang Liao ◽  
Der-Min Tsay ◽  
Bor-Jeng Lin
Keyword(s):  
Power Flow ◽  
Transmission Mechanism ◽  
Variable Speed ◽  
Constant Frequency ◽  
Torque Distribution ◽  
Input Shaft ◽  
Variable Speed Wind Turbine ◽  
Variable Transmission ◽  
Infinitely Variable Transmission ◽  
Parallel Type

This study proposes an innovative transmission mechanism, called parallel-type independently controllable transmission (ICT). The proposed mechanism can provide functions similar to those of infinitely variable transmission (IVT) or continuously variable transmission (CVT) mechanisms. The parallel-type ICT can transmit rotational output speed that can be independently regulated using a controller and is unaffected by the speed variation of the input shaft. Thus, a variable speed wind turbine can generate electricity with a constant frequency and improved quality. The kinematic characteristics, torque distribution, and power flow of this transmission mechanism were verified using a prototype of the ICT to demonstrate the feasibility of its application.

Self-Powered Flywheel-Infinitely Variable Transmission Actuator for Artificial Knee Joints

2017 ◽  
Vol 11 (3) ◽  
pp. 361-367
Author(s):  
Roberta Aló ◽  
◽  
Francesco Bottiglione ◽  
Giacomo Mantriota
Keyword(s):  
Knee Joint ◽  
Knee Joints ◽  
Total Power ◽  
Speed Ratio ◽  
Power Requirement ◽  
Human Knee ◽  
Wearable Robots ◽  
Variable Transmission ◽  
Infinitely Variable Transmission ◽  
Self Powered

The efficient energetics of human walking could possibly be used to fulfill the total power requirement of human knee, without requiring any additional sources of energy. This study intends to addresses this issue by examining the idea of a novel self-powered actuator for artificial knee joints of wearable robots. The self-powered Flywheel-Infinitely Variable Transmission (F-IVT) is an actuator whose only source of power is a flywheel that stores and delivers energy from and to the knee joint by changing the speed ratio of the IVT according to the phase of the gait cycle. This study evaluates the efficacy of this novel actuator by estimating the amount of energy it can deliver to the knee joint while the subject walks on level ground at varied speeds.

Design, Modeling, and Experimental Validation of a Novel Infinitely Variable Transmission Based on Scotch Yoke Systems

2015 ◽  
Vol 138 (1) ◽  
Author(s):  
X. F. Wang ◽  
W. D. Zhu
Keyword(s):  
Planetary Gear ◽  
Speed Ratio ◽  
Control Module ◽  
Kinematic Behavior ◽  
Input Control ◽  
Variable Transmission ◽  
Infinitely Variable Transmission ◽  
Planetary Gear Sets ◽  
Noncircular Gears ◽  
Crank Length

A novel infinitely variable transmission (IVT) based on scotch yoke systems is designed to provide a continuously varied output-to-input speed ratio from zero to a specified value. By changing the crank length of scotch yoke systems, the speed ratio of the IVT can be continuously adjusted. The IVT consists of a pair of noncircular gears and two modules: an input-control module and a motion conversion module. The input-control module employs two planetary gear sets to combine the input speed of the IVT with the control speed from the stepper motor that changes the crank length of scotch yoke systems. The motion conversion module employs two scotch yoke systems to convert the combined speeds from the input-control module to translational speeds of yokes, and the translational speeds are converted to output speeds through rack–pinions. The speed ratio between the output of the motion conversion module and the input of the input-control module has a shape of a sinusoidal-like wave, which generates instantaneous variations. Use of scotch yoke systems provides a benefit to isolate the interaction between the crank length and the shape of the speed ratio, and a pair of noncircular gears can be used to eliminate the instantaneous variations of the speed ratio for all crank lengths. A prototype of the IVT was built and instrumented, and its kinematic behavior was experimentally validated. A driving test was conducted to examine the performance of the IVT.

A New Technique for Scan Chain Failure Diagnosis

2002 ◽  
Author(s):  
Ruifeng Guo ◽  
Srikanth Venkataraman
Keyword(s):  
Hold Time ◽  
Failure Diagnosis ◽  
Second Step ◽  
Fault Type ◽  
Transition Faults ◽  
Input Side ◽  
Output Side ◽  
A New Technique ◽  
Scan Chain ◽  
Diagnostic Resolution

Abstract In this paper, we present a scan chain fault diagnosis procedure. The diagnosis for a single scan chain failure is performed in three steps. The first step uses special chain test patterns to determine both the faulty chain and the fault type in the faulty chain. The second step uses a novel procedure to generate special test patterns to identify the suspect scan cell within a range of scan cells. Unlike previously proposed methods that restrict the location of the faulty scan cell only from the scan chain output side, our method restricts the location of the faulty scan cell from both the scan chain output side and the scan chain input side. Hence the number of suspect scan cells is reduced significantly in this step. The final step further improves the diagnostic resolution by ranking the suspect scan cells inside this range. The proposed technique handles both stuck-at and timing failures (transition faults and hold time faults). The experimental results based on simulation and silicon units for several products show the effectiveness of the proposed method.

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