Theoretical and Experimental Analysis of a Cycloidal Speed Reducer

2007 ◽  
Author(s):  
Piermaria Davoli ◽  
Carlo Gorla ◽  
Francesco Rosa ◽  
Claudio Longoni ◽  
Franco Chiozzi ◽  
...  
Keyword(s):  
Theoretical Model ◽  
Structural Characteristics ◽  
Design Procedure ◽  
Experimental Tests ◽  
Mechanical Efficiency ◽  
Industrial Applications ◽  
Fine Tuning ◽  
Design Parameters ◽  
Good Efficiency ◽  
Speed Reducer

Compared with common speed reducers, the cycloidal ones (also known as cycloid drives) cover a wider range of transmission ratios, have a higher load-carrying capacity, are smaller, exhibit a smoother running and a good efficiency. These characteristics make them attractive for industrial applications, especially for robotics applications, machine tools and linear axis positioning in assembly machinery. In this paper, a theoretical and experimental investigation on an innovative cycloidal speed reducer will be presented. The typical cycloid drive has a planet wheel, the profile of which is the inner offset of an epitrochoid, meshing with cylindrical rollers connected to the case. This reducer, on the contrary, has an external ring gear, the transverse profile of which is the external offset of an epitrochoid, and engages with the planet wheel by means of cylindrical rollers. This paper will investigate the structural characteristics and the kinematical principles of this type of reducer. A theoretical approach based on the envelope theory (following Litvin’s approach) will be developed and compared with a development of Blanche and Yang’s approach. Furthermore, a simplified procedure to calculate force distribution on cycloid drive elements, as well as its power losses and theoretical mechanical efficiency will be presented. The effects of design parameters on the values of the forces will be studied, for an optimal design of this type of reducer. The theoretical model will be then tuned using the results of tests on a specific rig. As a result of the experimental tests, the reducer mechanical efficiency dependency on speed and torque will be described. The aim of this work is to perform the fine tuning of a theoretical model in order to predict the operating behavior of the cycloid drive, and to improve its design procedure.

Theoretical and Experimental Analysis of a Cycloidal Speed Reducer

2008 ◽  
Vol 130 (11) ◽  
Author(s):  
Carlo Gorla ◽  
Piermaria Davoli ◽  
Francesco Rosa ◽  
Claudio Longoni ◽  
Franco Chiozzi ◽  
...  
Keyword(s):  
Theoretical Model ◽  
Structural Characteristics ◽  
Design Procedure ◽  
Mechanical Efficiency ◽  
Design Parameters ◽  
Ring Gear ◽  
Power Losses ◽  
Transverse Profile ◽  
Speed Reducer ◽  
Simplified Procedure

In this paper, a theoretical and experimental investigation on an innovative cycloidal speed reducer is presented. The typical cycloid drive has a planet wheel, the profile of which is the internal offset of an epitrochoid meshing with cylindrical rollers connected to the case. This reducer, on the contrary, has an external ring gear, the transverse profile of which is the external offset of an epitrochoid and engages with the planet wheel by means of cylindrical rollers. This paper investigates the structural characteristics and the kinematic principles of this type of reducer. A theoretical approach based on the theory of gearing (following Litvin’s approach) is developed and compared to a development of Blanche and Yang’s approach. Furthermore, a simplified procedure to calculate the force distribution on cycloid drive elements, its power losses, and theoretical mechanical efficiency is presented. The effects of design parameters on the values of forces are studied for an optimal design of this type of reducer. The theoretical model is tuned on the basis of the results of tests made on purpose. The mechanical efficiency dependency on speed and torque is described. The main aim of this work is to tune a theoretical model in order to predict the operating behavior of the cycloid drive and to improve its design procedure.

scholarly journals Development of Dynamics for Design Procedure of Novel Grating Tiling Device with Experimental Validation

2021 ◽  
Vol 11 (24) ◽  
pp. 11716
Author(s):  
Qingshun Bai ◽  
Mohamed Shehata ◽  
Ayman Nada ◽  
Zhongxi Shao
Keyword(s):  
Dimensional Space ◽  
Three Dimensional ◽  
Real Life ◽  
Design Procedure ◽  
Industrial Applications ◽  
Differential Algebraic Equations ◽  
System Stability ◽  
Design Parameters ◽  
Measuring Instruments ◽  
Algebraic Equations

The article proposes a dynamic for design (DFD) procedure for a novel aperture grating tiling device using the multibody system (MBS) approach. The grating device is considered as a rigid-flexible MBS that is built primarily based totally at the load assumptions because of grating movement. This movement is utilized in many industrial applications, such as the compression of laser pulse, precision measuring instruments, and optical communication. A new design procedure of tiling grating device frame is introduced in order to optimize its design parameters and enhance the system stability. The dynamic loads are estimated based on the Lagrange multipliers that are obtained from the solution of the MBS model. This model is fully non-linear and moves in the three-dimensional space, and the relative movement of its bodies is restricted by the description of the constraints function in the motion manifold. The mechanism of the grating device is structurally analyzed in keeping with the dynamic conduct and therefore the generated forces. The symbolic manipulation as well as the computational work of solving the obtained differential-algebraic equations (DAEs) is carried out using MATLAB Symbolic Toolbox. Once the preliminary design has been attained, the stress behavior of the grating device is examined using the MATLAB FEATool Multiphysics toolkit, regarding system stability and design aspects. Moreover, the design was constructed in real life, and the movement has been verified experimentally, which confirms the effectiveness of the proposed procedure. In conclusion, the DFD procedure with trade-off optimization is utilized successfully to design the grating unit for maximum ranges of grating movements.

Compliant Foil Bearing Structural Stiffness Analysis—Part II: Experimental Investigation

1993 ◽  
Vol 115 (3) ◽  
pp. 364-369 ◽  
Author(s):  
C.-P. Roger Ku ◽  
Hooshang Heshmat
Keyword(s):  
Theoretical Model ◽  
Structural Characteristics ◽  
Tracking System ◽  
Operating Conditions ◽  
Optical Tracking ◽  
Design Parameters ◽  
Friction Forces ◽  
Foil Bearings ◽  
Light Load ◽  
Wide Range

This paper describes the second part of an investigation into the mechanism of deformation of the corrugated foil (bump foil) strips used in compliant surface foil bearings. In the earlier work, a theoretical model was developed to predict the structural characteristics of bump foil strips under various loads, including the effects of the friction forces between the compliant elements, local interaction forces, load distribution profiles, and bump configurations. In the experiments described here in, two-dimensional deflections of bump foils were recorded via an optical tracking system for a wide range of operating conditions to verify the feasibility of the theoretical model. Test results corroborate the theoretical model for the linear regions of load and the deflection parameters. The effects of the bearing design parameters, such as bump configuration, load profile, and surface coating and lubricant, on the structural characteristics of the bump foil strip were investigated. In addition, the source and mechanism of nonlinear behavior of the bump foil strips under light load conditions were examined, and more effective methods of achieving both Coulomb damping and optimum structural compliance were investigated. An understanding of the analytical and semi-empirical relations resulting from this work offers designers the potential for enhancing the design of high-performance compliant foil bearings.

The influence of confocal microscope design on imaging performance

1993 ◽  
Vol 51 ◽  
pp. 144-145
Author(s):  
C J R Sheppard
Keyword(s):  
Image Quality ◽  
Fluorescence Imaging ◽  
Confocal Microscope ◽  
Industrial Applications ◽  
Three Dimensions ◽  
Design Parameters ◽  
Weak Signals ◽  
Size And Shape ◽  
Imaging Performance ◽  
Fundamental Limitation

The confocal microscope is now widely used in both biomedical and industrial applications for imaging, in three dimensions, objects with appreciable depth. There are now a range of different microscopes on the market, which have adopted a variety of different designs. The aim of this paper is to explore the effects on imaging performance of design parameters including the method of scanning, the type of detector, and the size and shape of the confocal aperture.It is becoming apparent that there is no such thing as an ideal confocal microscope: all systems have limitations and the best compromise depends on what the microscope is used for and how it is used. The most important compromise at present is between image quality and speed of scanning, which is particularly apparent when imaging with very weak signals. If great speed is not of importance, then the fundamental limitation for fluorescence imaging is the detection of sufficient numbers of photons before the fluorochrome bleaches.

scholarly journals AC Current Ripple in Three-Phase Four-Leg PWM Converters with Neutral Line Inductor

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1430
Author(s):  
Aleksandr Viatkin ◽  
Riccardo Mandrioli ◽  
Manel Hammami ◽  
Mattia Ricco ◽  
Gabriele Grandi
Keyword(s):  
Numerical Simulations ◽  
Pulse Width Modulation ◽  
Neutral Line ◽  
Experimental Tests ◽  
Performance Comparison ◽  
Design Parameters ◽  
Switching Frequency ◽  
Three Phase ◽  
Ac Current ◽  
Current Ripple

This paper presents a comprehensive study of peak-to-peak and root-mean-square (RMS) values of AC current ripples with balanced and unbalanced fundamental currents in a generic case of three-phase four-leg converters with uncoupled AC interface inductors present in all three phases and in neutral. The AC current ripple characteristics were determined for both phase and neutral currents, considering the sinusoidal pulse-width modulation (SPWM) method. The derived expressions are simple, effective, and ready for accurate AC current ripple calculations in three- or four-leg converters. This is particularly handy in the converter design process, since there is no need for heavy numerical simulations to determine an optimal set of design parameters, such as switching frequency and line inductances, based on the grid code or load restrictions in terms of AC current ripple. Particular attention has been paid to the performance comparison between the conventional three-phase three-leg converter and its four-leg counterpart, with distinct line inductance values in the neutral wire. In addition to that, a design example was performed to demonstrate the power of the derived equations. Numerical simulations and extensive experimental tests were thoroughly verified the analytical developments.

scholarly journals A Two-Round Optimization Design Method for Aerostatic Spindles Considering the Fluid–Structure Interaction Effect

2021 ◽  
Vol 11 (7) ◽  
pp. 3017
Author(s):  
Qiang Gao ◽  
Siyu Gao ◽  
Lihua Lu ◽  
Min Zhu ◽  
Feihu Zhang
Keyword(s):  
Optimal Design ◽  
Optimization Design ◽  
Design Method ◽  
Fluid Structure Interaction ◽  
Design Procedure ◽  
Design Parameters ◽  
Geometrical Parameters ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Aerostatic Spindle

The fluid–structure interaction (FSI) effect has a significant impact on the static and dynamic performance of aerostatic spindles, which should be fully considered when developing a new product. To enhance the overall performance of aerostatic spindles, a two-round optimization design method for aerostatic spindles considering the FSI effect is proposed in this article. An aerostatic spindle is optimized to elaborate the design procedure of the proposed method. In the first-round design, the geometrical parameters of the aerostatic bearing were optimized to improve its stiffness. Then, the key structural dimension of the aerostatic spindle is optimized in the second-round design to improve the natural frequency of the spindle. Finally, optimal design parameters are acquired and experimentally verified. This research guides the optimal design of aerostatic spindles considering the FSI effect.

Development of an End-Effector for Mitigation of Collisions

2021 ◽  
Author(s):  
Domenico Tommasino ◽  
Matteo Bottin ◽  
Giulio Cipriani ◽  
Alberto Doria ◽  
Giulio Rosati
Keyword(s):  
Numerical Simulations ◽  
Industrial Applications ◽  
Operating Conditions ◽  
Contact Forces ◽  
Design Parameters ◽  
End Effector ◽  
Linear Behavior ◽  
Stable Mechanism ◽  
Robot Tasks ◽  
The Impact

Abstract In robotics the risk of collisions is present both in industrial applications and in remote handling. If a collision occurs, the impact may damage both the robot and external equipment, which may result in successive imprecise robot tasks or line stops, reducing robot efficiency. As a result, appropriate collision avoidance algorithms should be used or, if it is not possible, the robot must be able to react to impacts reducing the contact forces. For this purpose, this paper focuses on the development of a special end-effector that can withstand impacts and is able to protect the robot from impulsive forces. The novel end-effector is based on a bi-stable mechanism that decouples the dynamics of the end-effector from the dynamics of the robot. The intrinsically non-linear behavior of the end-effector is investigated with the aid of numerical simulations. The effect of design parameters and the operating conditions are analyzed and the interaction between the functioning of the bi-stable mechanism and the control system is studied. In particular, the effect of the mechanism in different scenarios characterized by different robot velocities is shown. Results of numerical simulations assess the validity of the proposed end-effector, which can lead to large reductions in impact forces.

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 Design of Biomechanical Legs with a Passive Toe Joint for Enhanced Human-like Walking

2017 ◽  
Vol 14 (2) ◽  
pp. 166 ◽  
Author(s):  
Riadh Zaier ◽  
A. Al-Yahmedi
Keyword(s):  
Design Procedure ◽  
Human Walking ◽  
Human Gait ◽  
Design Parameters ◽  
Sultan Qaboos University ◽  
Motion Trajectories ◽  
Normal Human ◽  
Working Principle ◽  
Mass Spring ◽  
Torsion Springs

This paper presents the design procedure of a biomechanical leg, with a passive toe joint, which is capable of mimicking the human walking. This leg has to provide the major features of human gait in the motion trajectories of the hip, knee, ankle, and toe joints. Focus was given to the approach of designing the passive toe joint of the biomechanical leg in its role and effectiveness in performing human like motion. This study was inspired by experimental and theoretical studies in the fields of biomechanics and robotics. Very light materials were mainly used in the design process. Aluminum and carbon fiber parts were selected to design the proposed structure of this biomechanical leg, which is to be manufactured in the Mechanical Lab of the Sultan Qaboos University (SQU). The capabilities of the designed leg to perform the normal human walking are presented. This study provides a noteworthy and unique design for the passive toe joint, represented by a mass-spring damper system, using torsion springs in the foot segment. The working principle and characteristics of the passive toe joint are discussed.  Four-designed cases, with different design parameters, for the passives toe joint system are presented to address the significant role that the passive toe joint plays in human-like motion. The dynamic motion that is used to conduct this comparison was the first stage of the stance motion. The advantages of the presence of the passive toe joint in gait, and its effect on reducing the energy consumption by the other actuated joints are presented and a comparison between the four-designed cases is discussed.

scholarly journals ARMOUR UNIT STRUCTURAL RESPONSE - A PARAMETRIC STUDY

1988 ◽  
Vol 1 (21) ◽  
pp. 176
Author(s):  
C. David Anglin ◽  
William F. Baird ◽  
Etienne P.D. Mansard ◽  
R. Douglas Scott ◽  
David J. Turcke
Keyword(s):  
Wave Height ◽  
Parametric Study ◽  
Structural Integrity ◽  
Design Procedure ◽  
Structural Response ◽  
Design Parameters ◽  
Coastal Structures ◽  
Log Normal ◽  
Wave Induced ◽  
Hydraulic Stability

There is a general lack of knowledge regarding the nature and magnitude of loads acting on armour units used for the protection of rubblemound coastal structures. Thus, a comprehensive design procedure incorporating both the hydraulic stability and the structural integrity of the armour units does not exist. This paper presents the results of a detailed parametric study of the structural response of armour units to wave-induced loading in a physical breakwater model. The effect of the following design parameters is investigated: breakwater slope, armour unit location, wave period and wave height. This research has made a number of significant contributions towards the development of a comprehensive design procedure for concrete armour units. It has identified a linear relationship between the wave-induced stress in the armour units and the incident wave height. In addition, it has shown that the conditional probability of waveinduced stress given wave height can be estimated by a log-normal distribution. Finally, a preliminary design chart has been developed which incorporates both the structural integrity and the hydraulic stability of the armour units.

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