Pseudo-rigid-body dynamic modeling and analysis of compliant mechanisms

2017 ◽  
Vol 232 (9) ◽  
pp. 1665-1678 ◽  
Author(s):  
Yue-Qing Yu ◽  
Qian Li ◽  
Qi-Ping Xu
Keyword(s):  
Rigid Body ◽  
Dynamic Model ◽  
Dynamic Modeling ◽  
Dynamic Models ◽  
Compliant Mechanisms ◽  
Lagrange Equation ◽  
Dynamic Responses ◽  
Modeling And Analysis ◽  
Rigid Body Dynamic ◽  
Body Dynamic

An intensive study on the dynamic modeling and analysis of compliant mechanisms is presented in this paper based on the pseudo-rigid-body model. The pseudo-rigid-body dynamic model with single degree-of-freedom is proposed at first and the dynamic equation of the 1R pseudo-rigid-body dynamic model for a flexural beam is presented briefly. The pseudo-rigid-body dynamic models with multi-degrees-of-freedom are then derived in detail. The dynamic equations of the 2R pseudo-rigid-body dynamic model and 3R pseudo-rigid-body dynamic model for the flexural beams are obtained using Lagrange equation. Numerical investigations on the natural frequencies and dynamic responses of the three pseudo-rigid-body dynamic models are made. The effectiveness and superiority of the pseudo-rigid-body dynamic model has been shown by comparing with the finite element analysis method. An example of a compliant parallel-guiding mechanism is presented to investigate the dynamic behavior of the mechanism using the 2R pseudo-rigid-body dynamic model.

Kinematic and dynamic analysis of compliant mechanisms considering both lateral and axial deformations of flexural beams

2018 ◽  
Vol 233 (3) ◽  
pp. 1007-1020 ◽  
Author(s):  
Yue-Qing Yu ◽  
Peng Zhou ◽  
Qi-Ping Xu
Keyword(s):  
Rigid Body ◽  
Dynamic Analysis ◽  
Dynamic Model ◽  
Compliant Mechanisms ◽  
Dynamic Responses ◽  
Flexible Beams ◽  
Rigid Body Dynamic ◽  
Body Model ◽  
Rigid Body Model ◽  
Body Dynamic

The kinematic and dynamic analysis of compliant mechanisms is investigated comprehensively in this work. Based on the pseudo-rigid-body model, a new PR model is proposed to simulate both the lateral and axial deformations of flexural beams in compliant mechanisms. An optimization for the characteristic factors and a linear regression for the stiffness coefficients of PR pseudo-rigid-body model are presented. Compared with the 1R and 2R pseudo-rigid-body model, the advantage of the PR model is well illustrated. The dynamic modeling of flexible beams in compliant mechanisms is then developed based on the PR pseudo-rigid-body model. The dynamic equation of a PR pseudo-rigid-body dynamic model is derived and the dynamic responses are then presented. The kinematic and dynamic analysis of a compliant slider-crank mechanism is presented by the 1R, 2R and PR model, respectively. The effectiveness of pseudo-rigid-body models and the superiorities of the PR pseudo-rigid-body model and PR pseudo-rigid-body dynamic model are shown clearly in the numerical example.

Pseudo-Rigid-Body Dynamic Models for Design of Compliant Members

2019 ◽  
Vol 142 (3) ◽  
Author(s):  
Vedant ◽  
James T. Allison
Keyword(s):  
Rigid Body ◽  
Dynamic Models ◽  
Compliant Mechanisms ◽  
Flexible Beam ◽  
Dynamical Response ◽  
Structural Members ◽  
Element Analysis ◽  
Rigid Body Dynamic ◽  
Revolute Joints ◽  
Body Dynamic

Abstract Movement in compliant mechanisms is achieved, at least in part, via deformable flexible members, rather than using articulating joints. These flexible members are traditionally modeled using finite element analysis (FEA)-based models. In this article, an alternative strategy for modeling compliant cantilever beams is developed with the objectives of reducing computational expense and providing accuracy with respect to design optimization solutions. The method involves approximating the response of a flexible beam with an n-link/m-joint pseudo-rigid-body dynamic model (PRBDM). Traditionally, static pseudo-rigid-body models (PRBMs) have shown an approximation of compliant elements using two or three revolute joints (2R/3R-PRBM). In this study, a more general nR-PRBDM model is developed. The first n resonant frequencies of the PRBDM are matched to exact or FEA solutions to approximate the response of the compliant system and compared with existing PRBMs. PRBDMs can be used for co-design studies of flexible structural members and are capable of modeling large deflections of compliant elements. We demonstrate PRBDMs that show dynamically accurate response for a random geometry cantilever beam by matching the steady-state and frequency response, with dynamical response accuracies up to 10% using a 5R-PRBDM.

Dynamic Modeling and Response Analysis of a Planar Rigid-Body Mechanism With Clearance

2019 ◽  
Vol 14 (5) ◽  
Author(s):  
Chen Xiulong ◽  
Jiang Shuai ◽  
Deng Yu ◽  
Wang Qing
Keyword(s):  
Rigid Body ◽  
Dynamic Model ◽  
Dynamic Modeling ◽  
Contact Force ◽  
Kinematic Model ◽  
Dynamic Responses ◽  
Response Analysis ◽  
Prototype Model ◽  
Force Model ◽  
Normal Contact

In order to understand dynamic responses of planar rigid-body mechanism with clearance, the dynamic model of the mechanism with revolute clearance is proposed and the dynamic analysis is realized. First, the kinematic model of the revolute clearance is built; the amount of penetration depth and relative velocity between the elements of the revolute clearance joint is obtained. Second, Lankarani-Nikravesh (L-N) and the novel nonlinear contact force model are both used to describe the normal contact force of the revolute clearance, and the tangential contact force of the revolute clearance is built by modified Coulomb friction model. Third, the dynamic model of a two degrees-of-freedom (2DOFs) nine bars rigid-body mechanism with a revolute clearance is built by the Lagrange equation. The fourth-order Runge–Kutta method has been utilized to solve the dynamic model. And the effects of different driving speeds of cranks, different clearance values, and different friction coefficients on dynamic response are analyzed. Finally, in order to prove the validity of numerical calculation result, the virtual prototype model of 2DOFs nine bars mechanism with clearance is modeled and its dynamic responses are analyzed by adams software. This research could supply theoretical basis for dynamic modeling, dynamic behaviors analysis, and clearance compensation control of planar rigid-body mechanism with clearance.

Dynamic Modeling and Analysis of a Fruit and Vegetable Picking Robot

2012 ◽  
Vol 241-244 ◽  
pp. 1845-1849
Author(s):  
Yan Wang ◽  
Yun Wang Ge ◽  
Xiao Li Wang
Keyword(s):  
Dynamic Modeling ◽  
Trajectory Planning ◽  
Dynamic Models ◽  
Lagrange Equation ◽  
Angular Displacement ◽  
Fruit And Vegetable ◽  
Robot System ◽  
Modeling And Analysis ◽  
Abrupt Changes ◽  
Simulation Results

According to characteristics of the fruit and vegetable picking operations, an articulated picking robot with four degree-of-freedom is developed. And in order to perform an expected motion of picking work, the kinematic and dynamic models have to be constructed firstly. Kinematics is established based on Denavit-Hartenberg notation. Then, the explicit expressions of dynamic models are presented through Lagrange equation. Finally, trajectory planning from one point to another point is carried out with cycloidal motion, and the angular displacement, velocity, acceleration and torque curves of each joint are analyzed. Simulation results show that the torque curves are quite smooth and with no abrupt changes, which indicates that the motions of each joint won’t result vibrations and can ensure stability of the robot system.

Investigating Rigidity of Military Vehicle Body Using Operating Deflection Shape (ODS) Analysis

2006 ◽  
Vol 49 (2) ◽  
pp. 16-24 ◽  
Author(s):  
Mark Bounds ◽  
George White
Keyword(s):  
Rigid Body ◽  
Dynamic Models ◽  
The Body ◽  
Vehicle Body ◽  
Rigid Body Dynamic ◽  
Military Vehicle ◽  
Acceleration Data ◽  
Specific Frequency ◽  
Body Dynamic ◽  
Insight Into

The Army has many rigid-body dynamic models of various vehicle platforms. The adequacy of these rigid-body models has been questioned. In an effort to gain insight into the significance of flexibility in the development of dynamic vehicle models, operating deflection shape (ODS) techniques were applied to acceleration data gathered from the body of a wheeled military vehicle. The data were analyzed in an effort to determine a specific frequency range over which the assumption of rigidity would be valid. For the particular platform examined in this study, the assumption of rigidity would apply up to approximately 14 Hz. Future efforts include using operational modal analysis (OMA) to further examine the problem.

Pseudo-Rigid Body Dynamic Modeling of Compliant Members for Design

2019 ◽  
Author(s):  
Vedant ◽  
James T. Allison
Keyword(s):  
Rigid Body ◽  
Compliant Mechanisms ◽  
Flexible Beam ◽  
Finite Element Models ◽  
Structural Members ◽  
Resonant Frequencies ◽  
Design Studies ◽  
Rigid Body Dynamic ◽  
Revolute Joints ◽  
Body Dynamic

Abstract Movement in compliant mechanisms is achieved, at least in part, via deformable flexible members, rather than using articulating joints. These flexible members are traditionally modeled using Finite Element Models (FEMs). In this article, an alternative strategy for modeling compliant cantilever beams is developed with the objectives of reducing computational expense, and providing accuracy with respect to design optimization solutions. The method involves approximating the response of a flexible beam with an n-link/m-joint Pseudo-Rigid Body Dynamic Model (PRBDM). Traditionally, PRBDM models have shown an approximation of compliant elements using 2 or 3 revolute joints (2R/3R-PRBDM). In this study, a more general nR-PRBDM model is developed. The first n resonant frequencies of the PRBDM are matched to exact or FEM solutions to approximate the response of the compliant system. These models can be used for co-design studies of flexible structural members, and are capable of modeling higher deflection of compliant elements.

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