Design of a Self-Actuating, Traction Drive Speed Reducer

2000 ◽  
Author(s):  
Donald R. Flugrad ◽  
Abir Z. Qamhiyah
Keyword(s):  
Friction Coefficient ◽  
Normal Force ◽  
Drive System ◽  
Traction Drive ◽  
Sliding Motion ◽  
Output Torque ◽  
Speed Reducer ◽  
Rolling Elements ◽  
Drive Speed ◽  
High Output

Abstract Traction drive speed reducers offer certain advantages over geared speed reducers. In particular, they generally run quieter than geared units, and they provide an opportunity for higher efficiency by eliminating sliding motion between contacting elements. In order to generate a sufficiently high output torque, some means must be provided to create a normal force between the rolling elements. This normal force, along with the friction coefficient, enables the device to transmit torque from one rolling member to the next. The speed reducer proposed here is designed so that the configuration of the rolling elements creates the needed normal force in response to the torque exerted back on the system by the downstream loading. Thus the device is self-actuating. Since the normal force is only present when needed, the rolling elements of the device can readily be disengaged. This eliminates the need for a separate clutch in the drive system. This feature can be exploited to design a transmission with several distinct speed ratios which can be engaged and disengaged in response to changing speed requirements.

A Self-Actuating Traction-Drive Speed Reducer

2004 ◽  
Vol 127 (4) ◽  
pp. 631-636 ◽  
Author(s):  
Donald R. Flugrad ◽  
Abir Z. Qamhiyah
Keyword(s):  
Friction Coefficient ◽  
Normal Force ◽  
Drive System ◽  
Traction Drive ◽  
Sliding Motion ◽  
Output Torque ◽  
Speed Reducer ◽  
Rolling Elements ◽  
Drive Speed ◽  
High Output

Traction-drive speed reducers offer certain advantages over geared speed reducers. In particular, they generally run quieter than geared units and provide an opportunity for higher efficiency by eliminating sliding motion between contacting elements. In order to generate a sufficiently high output torque, some means must be provided to create a normal force between the rolling elements. This normal force, along with the friction coefficient, enables the device to transmit torque from one rolling member to the next. The speed reducer proposed here is designed so that the configuration of the rolling elements creates the needed normal force in response to the torque exerted back on the system by the downstream loading. Thus the device is self-actuating. Since the normal force is only present when needed, the rolling elements of the device can readily be disengaged, thus eliminating the need for a separate clutch in the drive system. This feature can be exploited to design a transmission with several distinct speed ratios that can be engaged and disengaged in response to changing speed requirements.

scholarly journals Highly efficient traction drive system with a normal force controller using a piezoelectric actuator

2017 ◽  
Vol 9 (10) ◽  
pp. 168781401772883 ◽  
Author(s):  
Rui Fukui ◽  
Taira Okabe ◽  
Masayuki Nakao ◽  
Yukihiro Honda
Keyword(s):  
Piezoelectric Actuator ◽  
Normal Force ◽  
Drive System ◽  
Traction Drive ◽  
Highly Efficient

Automotive Traction Drive Speed Reducer Efficiency Testing

2021 ◽  
Author(s):  
Wei Wang ◽  
James M. Durack ◽  
Michael J. Durack ◽  
Jun Zhang ◽  
Peng Zhao
Keyword(s):  
Traction Drive ◽  
Speed Reducer ◽  
Drive Speed

Design of a Self-Actuating, Traction Drive System for High-Speed Ratios

2003 ◽  
Author(s):  
Michael J. Harper ◽  
Donald R. Flugrad ◽  
Abir Z. Qamhiyah
Keyword(s):  
High Speed ◽  
Power Transmission ◽  
Drive System ◽  
Speed Ratio ◽  
Rolling Motion ◽  
Traction Drive ◽  
Rolling Elements ◽  
Drive Systems ◽  
Two Stages ◽  
Efficient Power

Traction drive systems offer unique advantages over geared systems. They will typically run quieter and they can be designed to eliminate all backlash. Furthermore, rolling elements are easy to manufacture and the rolling motion will produce very efficient power transmission. In this paper the authors describe a two-stage, self-actuating, traction drive system that has been fabricated to produce a speed ratio of 50:1. Given specific values for coefficients of friction, the geometry of each stage of the device must be designed to ensure self-actuation. In addition, dimensions of the drive rollers and output rings for the two stages must be selected to ensure that one stage does not cause the other stage to overrun.

An optimal wheel-torque control on a compliant modular robot for wheel-slip minimization

Robotica ◽  
2015 ◽  
Vol 35 (2) ◽  
pp. 463-482 ◽  
Author(s):  
Avinash Siravuru ◽  
Suril V. Shah ◽  
K. Madhava Krishna
Keyword(s):  
Friction Coefficient ◽  
Normal Force ◽  
Experimental Studies ◽  
Traction Force ◽  
Static Stability ◽  
Wheel Speed ◽  
Torque Control ◽  
Modular Robot ◽  
Wheel Slip ◽  
Wheel Torque

SUMMARYThis paper discusses the development of an optimal wheel-torque controller for a compliant modular robot. The wheel actuators are the only actively controllable elements in this robot. For this type of robots, wheel-slip could offer a lot of hindrance while traversing on uneven terrains. Therefore, an effective wheel-torque controller is desired that will also improve the wheel-odometry and minimize power consumption. In this work, an optimal wheel-torque controller is proposed that minimizes the traction-to-normal force ratios of all the wheels at every instant of its motion. This ensures that, at every wheel, the least traction force per unit normal force is applied to maintain static stability and desired wheel speed. The lower this is, in comparison to the actual friction coefficient of the wheel-ground interface, the more margin of slip-free motion the robot can have. This formalism best exploits the redundancy offered by a modularly designed robot. This is the key novelty of this work. Extensive numerical and experimental studies were carried out to validate this controller. The robot was tested on four different surfaces and we report an overall average slip reduction of 44% and mean wheel-torque reduction by 16%.

Slip-Clutch Torque Estimation via Real-Time Adaptive Lookup Table

2021 ◽  
Vol 2 (2) ◽  
Author(s):  
Wenpeng Wei ◽  
Hussein Dourra ◽  
Guoming Zhu
Keyword(s):  
Friction Coefficient ◽  
Real Time ◽  
Mean Squared Error ◽  
Surface Friction ◽  
Lookup Table ◽  
Recursive Least Squares ◽  
Time Varying ◽  
Squared Error ◽  
Output Torque ◽  
Clutch Torque

Abstract Transfer case clutch is crucial in determining traction torque distribution between front and rear tires for four-wheel-drive (4WD) vehicles. Estimating time-varying clutch surface friction coefficient is critical for traction torque control since it is proportional to the clutch output torque. As a result, this paper proposes a real-time adaptive lookup table strategy to provide the time-varying clutch surface friction coefficient. Specifically, the clutch-parameter-dependent (such as clutch output torque and clutch touchpoint distance) friction coefficient is first estimated with available low-cost vehicle sensors (such as wheel speed and vehicle acceleration); and then a clutch-parameter-independent approach is developed for clutch friction coefficient through a one-dimensional lookup table. The table nodes are adaptively updated based on a fast recursive least-squares (RLS) algorithm. Furthermore, the effectiveness of adaptive lookup table is demonstrated by comparing the estimated clutch torque from adaptive lookup table with that estimated from vehicle dynamics, which achieves 14.8 Nm absolute mean squared error (AMSE) and 2.66% relative mean squared error (RMSE).

High-Cycle Fatigue of Shafts due to Starting Transients in Drive Systems

1988 ◽  
Vol 202 (3) ◽  
pp. 201-209 ◽  
Author(s):  
S G Velonias ◽  
N A Aspragathos
Keyword(s):  
Structural Characteristics ◽  
Drive System ◽  
Suggested Approach ◽  
Loss Of Life ◽  
Speed Reducer ◽  
Starting Conditions ◽  
General Drive ◽  
Drive Systems ◽  
Non Linear System ◽  
Spring Constants

This paper investigates some of the effects that structural characteristics and main non-linearities of a drive system have on systems response and its shaft fatigue. In the suggested approach a general drive system, including a motor, load and speed reducers, is modelled as a multi-degree-of-freedom torsional vibrations non-linear system. The differential equations of the system are formed automatically. The user of the developed program must input just the constants of the components. An algorithm to compute the loss of life of the shafts due to fatigue is also incorporated into the program. As an example, a drive system, including a motor, a speed reducer and load is modelled and tested under starting conditions. The effects of changing spring constants of the shafts and the backlash of the speed reducer are investigated.

scholarly journals Modelling of Friction Coefficient for Shoes Type LL By Means of Polynomial Fitting

2018 ◽  
Vol 12 (1) ◽  
pp. 114-127 ◽  
Author(s):  
L. Cantone ◽  
A. Ottati
Keyword(s):  
Experimental Data ◽  
Friction Coefficient ◽  
Input Data ◽  
Normal Force ◽  
Loading Conditions ◽  
Polynomial Fitting ◽  
Maximum Acceleration ◽  
Stopping Distance ◽  
Freight Traffic ◽  
Brake Cylinder

Introduction: The paper describes the automatic procedure, implemented in UIC software TrainDy, for the simulation of friction coefficient of new LL shoes, used to avoid noise from freight traffic. Method: This procedure uses certified experimental data obtained at dynamometer bench as input data and computes a series of polynomials laws that describe the evolution of friction coefficient with speed, for different values of normal force between brake blocks and wheel and for different initial braking speeds. Result: Numerical results are compared against two series of experimental slip tests, carried on Trenitalia freight wagons, in terms of both stopping distances (for different starting speeds and loading conditions) and pressure in brake cylinder, speed and acceleration. Errors in terms of stopping distance are always below 5% whereas errors in terms of maximum acceleration are up to 20%.

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