Comparison of Open Chain and Closed Chain Planar Two Degree of Freedom Manipulator for Positional Error

2014 ◽  
Vol 6 (2) ◽  
Author(s):  
H. P. Jawale ◽  
H. T. Thorat
Keyword(s):  
Geometric Approach ◽  
Degree Of Freedom ◽  
The Other ◽  
Dimensionless Number ◽  
Positional Error ◽  
Positional Accuracy ◽  
Open Chain ◽  
Closed Chain ◽  
Error Index ◽  
Two Degree Of Freedom

Open chain and closed chain manipulators are designed for specific objectives. Closed chain five bar manipulator is possible to be configured as a substitute to an open chain two degree of freedom (DoF) manipulator. Positional accuracy is one of the factors for performance evaluation, characterizing suitability of a configuration over the other. Present paper attempts comparative analysis of positional inaccuracy of closed chain five bar manipulator and serial chain configuration. Both manipulators are modeled for positional deviations under identical specifications considering randomness due to joint clearances and backlash in drive. The maximum positional inaccuracy is expressed in terms of dimensionless number as error index (EI) to estimate the comparative behavior of the manipulators. Positional error under influence of backlash and clearances is quantified. Comparison of two configurations is presented and conditional superiority of a configuration over the other is commented using geometric approach.

Positional Accuracy Analysis in Serial Chain and Four-Bar Closed Chain Manipulator

2014 ◽  
Author(s):  
H. P. Jawale ◽  
H. T. Thorat
Keyword(s):  
Sample Path ◽  
Dimensionless Number ◽  
Positional Error ◽  
Input Constraints ◽  
Positional Accuracy ◽  
Serial Chain ◽  
Closed Chain ◽  
Serial Robot ◽  
Joint Clearances ◽  
Error Index

Serial chain robots are integral part of industrial automation. Better reach within workspace, higher Degree of Freedom (DoF), flexibility and positional accuracy are credit performance features behind its wide acceptance. The flexibility and higher DoF of this configuration is underutilized, when it is used for a repetitive task in hard automation. The present paper considers application of closed chain four-bar mechanism as substitute of a serial chain robot for repetitive task involving single trajectory generation. The manipulators are modelled for positional accuracy under the influence of joint clearances and drive backlash. The positional error in both manipulators for a coupler point on sample path is estimated. The manipulators are considered to operate with identical input constraints. The error is expressed in terms of dimensionless number-as Error Index to estimate the comparative behaviour of the manipulators. The paper presents method of analysing the performance of a closed chain manipulator over serial robot.

Investigation of Positional Error in Two Degree of Freedom Mechanism With Joint Clearance

2012 ◽  
Vol 4 (1) ◽  
Author(s):  
H. P. Jawale ◽  
H. T. Thorat
Keyword(s):  
Closed Loop ◽  
Robotic Manipulators ◽  
Simple Approach ◽  
Joint Clearance ◽  
Positional Error ◽  
Link Length ◽  
Positional Accuracy ◽  
Positional Analysis ◽  
Closed Chain ◽  
Two Degree Of Freedom

Closed chain mechanisms are used as robotic manipulators with special features. A planar two-DOF closed loop mechanism provides desired position of an end effecter in a confined workspace with two input motions. Position of end effecter depends on various factors including joint clearance. Positional accuracy forms important parameter for kinematic analysis of mechanism. This paper presents simple approach for quantifying error due to joint clearance in a two-DOF mechanism. Generalized scheme for positional deviation with and without clearance at joint is presented. Orientation of clearance links for maximum positional error is identified. Error at various positions is quantified in relation with clearance link length. Computer programming is used as a tool to workout positional analysis of mechanism. Results show that error is independent of magnitude of clearance, however, a function of location of end effecter in workspace.

scholarly journals Pendekatan Eksperimen Karakteristik Respon Getaran Sistem Two Degree of Freedom dengan Penambahan Independent Dual Dynamic Vibration Absorber

2019 ◽  
Vol 3 (2) ◽  
pp. 85
Author(s):  
Susastro Susastro ◽  
Novi Indah Riani
Keyword(s):  
Vibration Reduction ◽  
Degree Of Freedom ◽  
The Other ◽  
Vibration Absorber ◽  
Dynamic Vibration Absorber ◽  
Maximum Reduction ◽  
Dynamic Vibration ◽  
Translational Vibration ◽  
Mathematical Equations ◽  
Two Degree Of Freedom

Vibration is one of the problems that must be reduced in a vehicle. There are many ways to reduce vibration in vehicles, one of them is by adding Dynamic vibration absorber (DVA). While Dual Dynamic vibration absorber (dDVA) is a DVA period that is able to move in the translational direction given to the system to reduce translation vibration and when there is resonance. Translation DVA is an additional type of time used to reduce the vibration of the translation direction. So far there is not much research related to the use of translational DVA to reduce rotational vibrations as well as translation. In this study, a study was conducted related to the use of independent double translational DVA (dDVA) to reduce translation vibrations as well as rotation of the beam. The research was conducted by modeling the system obtained into mathematical equations and simulations were carried out to determine the characteristics of vibrations that arise. In the simulation, one of the DVA periods is placed at the center of the main system period, while the other DVA period is given a change between the center period and the end of the system. The results of the study show that the maximum reduction in translational vibration is 95.51% and occurs when the absorber is placed at the center of the system, while the maximum rotation vibration reduction is 56.62% and is obtained when the system is given with an arm ratio of 1 and zero.

Vibration Response of Linear Damped Complex Systems

1963 ◽  
Vol 30 (1) ◽  
pp. 70-74 ◽  
Author(s):  
Robert Plunkett
Keyword(s):  
Linear System ◽  
Complex Systems ◽  
Normal Modes ◽  
Continuous System ◽  
Vibration Response ◽  
Degree Of Freedom ◽  
The Other ◽  
Maximum Response ◽  
Approximate Expressions ◽  
Two Degree Of Freedom

Hahnkamm has found the changes in the amplitudes of each of the two maxima of the unit vibration response of a two-degree-of-freedom linear system as the strength of the single linear dashpot is changed. This paper develops two approximate expressions for the change in all of the response maxima of a multidegree or continuous system as the dashpot constant of the single linear damper is changed. One of these approximations is derived from a perturbation solution around the minimax values, and the other is derived from an expansion in normal modes. These expressions are useful in determining the sensitivity of the maximum response value to small changes in the damping constant.

Stability analysis of switched systems with extended average dwell time

2017 ◽  
Vol 40 (5) ◽  
pp. 1425-1434 ◽  
Author(s):  
Qiang Yu ◽  
Yunfei Yin ◽  
Xudong Zhao
Keyword(s):  
Stability Analysis ◽  
Continuous Time ◽  
Switched Systems ◽  
Dwell Time ◽  
Average Dwell Time ◽  
The Other ◽  
Open Chain ◽  
Closed Chain ◽  
Special Cases ◽  
Stability And Stabilization

The problem of stability for switched systems with extended average dwell time (ADT) is investigated in both the continuous-time and discrete-time cases. By proposing three novel concepts of closed-chain, r-open-chain, and quasi-cyclic switching signals, stability and stabilization conditions of switched systems with ADT or mode-dependent ADT (MDADT) switching are obtained. This paper develops and enriches the existing results on stability under constrained switching, since the existing results based on both ADT and MDADT can be seen as the special cases of ours. On the other hand, the paper provides a solution to the open problem of how to obtain a tighter bound on ADT or MDADT. Finally, some comparisons between the existing results and ours show the superiority of the theoretical findings of this paper.

A Geometric Approach for Establishing Dynamic Buckling Loads of Autonomous Potential Two-Degree-of-Freedom Systems

1999 ◽  
Vol 66 (1) ◽  
pp. 55-61 ◽  
Author(s):  
A. N. Kounadis
Keyword(s):  
Geometric Approach ◽  
Energy Balance Equation ◽  
Dynamic Buckling ◽  
Degree Of Freedom ◽  
Buckling Loads ◽  
Total Potential ◽  
Total Energy Balance ◽  
Highly Nonlinear ◽  
Planar Systems ◽  
Two Degree Of Freedom

Nonlinear dynamic buckling of autonomous potential two-degree-of-freedom nondissipative systems with static unstable critical points lying on nonlinear primary equilibrium paths is studied via a geometric approach. This is based on certain salient properties of the zero level total potential energy “surface” which in conjunction with the total energy-balance equation allow establishment of new dynamic buckling criteria for planar systems. These criteria yield readily obtained “exact” dynamic buckling loads without solving the highly nonlinear initial-value problem. The simplicity, reliability, and efficiency of the proposed technique is illustrated with the aid of various dynamic buckling analyses of two two-degree-of-freedom models which are also compared with those obtained by the Verner-Runge-Kutta scheme.

Two-Degree-of-Freedom Decoupled Nonredundant Cable-Loop-Driven Parallel Mechanism

2013 ◽  
Vol 6 (1) ◽  
Author(s):  
Hanwei Liu ◽  
Clément Gosselin ◽  
Thierry Laliberté
Keyword(s):  
Parallel Mechanism ◽  
Degrees Of Freedom ◽  
Degree Of Freedom ◽  
The Other ◽  
End Effector ◽  
Two Degrees Of Freedom ◽  
Actuation Redundancy ◽  
Rigid Link ◽  
Force Closure ◽  
Two Degree Of Freedom

A novel two-degree-of-freedom (DOF) cable-loop slider-driven parallel mechanism is introduced in this paper. The novelty of the mechanism lies in the fact that no passive rigid-link mechanism or springs are needed to support the end-effector (only cables are connected to the end-effector) while at the same time there is no actuation redundancy in the mechanism. Sliders located on the edges of the workspace are used and actuation redundancy is eliminated while providing force closure everywhere in the workspace. It is shown that the two degrees of freedom of the mechanism are decoupled and only two actuators are needed to control the motion. There are two cable loops for each direction of motion: one acts as the actuating loop while the other is the constraint loop. Due to the simple geometric design, the kinematic and static equations of the mechanism are very compact. The stiffness of the mechanism is also analyzed in the paper. It can be observed that the mechanism's stiffness is much higher than the stiffness of the cables. The proposed mechanism's workspace is essentially equal to its footprint and there are no singularities.

Development of 2-DOF Hybrid Actuator System

2012 ◽  
Vol 523-524 ◽  
pp. 733-738
Author(s):  
Ryota Okeya ◽  
Manabu Aoyagi
Keyword(s):  
Force Feedback ◽  
Piezoelectric Actuators ◽  
Degree Of Freedom ◽  
Performance Characteristics ◽  
The Other ◽  
Haptic Display ◽  
Different Types ◽  
Actuator System ◽  
Two Degree Of Freedom ◽  
Hybrid Actuator

Ordinal force-feedback devices mainly employ electromagnetic motors (EMMs), and are excellent at expressing springy sensations. However, it is not easy to express a realistic sense of hardness and roughness using such devices. On the other hand, an actuator system (AS) using multilayered piezoelectric actuators exhibits performance characteristics that are opposite to those of an ordinal AS using an EMM. The objective of the present study is to develop an ideal AS for a haptic display. A two-degree-of-freedom AS utilizing a pair of hybrid AS units, each consisting of an EMM, an ultrasonic motor and a piezoelectric clutch, is proposed and evaluated. Such an arrangement allows the different types of actuators to complement each other, thus compensating for their individual weaknesses. This hybrid AS can expand the range of representable sensations. The results show that the proposed AS can realistically express both hardness and softness by switching between actuator combinations.

Free Periodic Motions of an Undamped Two-Degree-of-Freedom Oscillatory System With Nonlinear Unsymmetrical Elasticity

1950 ◽  
Vol 17 (2) ◽  
pp. 185-190
Author(s):  
Walter W. Soroka
Keyword(s):  
Nonlinear Systems ◽  
Linear Systems ◽  
Oscillatory System ◽  
Degree Of Freedom ◽  
The Other ◽  
Periodic Motions ◽  
Deflection Curve ◽  
Approximate Treatment ◽  
Load Deflection Curve ◽  
Two Degree Of Freedom

Abstract Precise solutions are presented for a two-degree-of-freedom oscillatory system containing a preset spring. Such a system is characteristic of an aircraft propeller-engine-supercharger installation. The periodic free motions obtained indicate the possibility of highly unconventional motions when the nonlinearity is pronounced, motions which may be easily overlooked in the usual approximate treatment of nonlinear systems. The results presented in this paper show that one mass may oscillate several times while the other mass is going through one oscillation. The ratio of oscillations of one mass with respect to the other changes with amplitude. By considering the load-deflection curve for the nonlinear spring to be a broken line, periodic motions may be obtained to any desired degree of precision by combining conventional general solutions for two-degree-of-freedom linear systems.

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