Dynamic Analysis of Flexible Space Manipulators with Harmonic Reducer

2013 ◽  
Vol 584 ◽  
pp. 200-207 ◽  
Author(s):  
Jie Liang Zhao ◽  
Yong Xia Gu ◽  
Shao Ze Yan ◽  
Jia Ning Wu
Keyword(s):  
High Frequency ◽  
Dynamical Property ◽  
Hysteresis Phenomenon ◽  
Harmonic Drive ◽  
Dynamical Models ◽  
Space Manipulator ◽  
Space Manipulators ◽  
Nonlinear Dynamic Characteristics ◽  
Angular Velocities ◽  
Dynamical Properties

Space manipulator is an important tool for spacecraft to complete a variety of tasks in space. The trajectory precision of the manipulator determines whether the mechanism performs normally. Nowadays the harmonic drive is widely used as the reducer in the space manipulator, which may influence the dynamical properties of the flexible space manipulator. This paper establishes the dynamical models of space manipulator considering the harmonic hysteresis phenomenon derived from the harmonic reducer. A numerical simulation is proposed to analyze the nonlinear dynamic characteristics of flexible space manipulator with harmonic drive. The results of angular velocities reveal that non-linear and high-frequency disturbance detected in the output dynamical property is caused by flexibility of the space manipulator. Moreover, the observed hysteresis phenomenon in the dynamic behavior is not only determined by the flexibility of manipulator but the transmission feature embedded the harmonic drive.

Studies of a high frequency hysteresis phenomenon in ZnS:Mn actfel devices

1988 ◽  
Vol 40-41 ◽  
pp. 775-776 ◽  
Author(s):  
Changchang Zhu ◽  
Ralph C. McArthur ◽  
S.John T. Owen
Keyword(s):  
High Frequency ◽  
Hysteresis Phenomenon

Inverse kinematics of free-floating space robots with minimum dynamic disturbance

Robotica ◽  
1996 ◽  
Vol 14 (6) ◽  
pp. 667-675 ◽  
Author(s):  
Fengfeng Xi
Keyword(s):  
Inverse Kinematics ◽  
New Method ◽  
Space Robots ◽  
Simple Fact ◽  
Generalized Jacobian ◽  
Space Manipulator ◽  
End Effector ◽  
Dynamic Disturbance ◽  
Space Manipulators

In this paper a new method is presented for solving the inverse kinematics of free-floating space manipulators. The idea behind the method is to move the space manipulator along a path with minimum dynamic disturbance. The method is proposed to use the manipulator Jacobian instead of the generalized Jacobian of the spacecraft-manipulator system. This is based on the simple fact that, if the space manipulator moves along the so-called Zero Disturbance Path (ZDP), the spacecraft is immovable. As a result, the space manipulator can in this case be treated as a terrestrial fixed-based manipulator. Hence, the motion mapping between the joints and the end-effector can be described directly by the manipulator Jacobian. In the case that the ZDP does not exist, it can be shown that the solutions obtained by the proposed method provide a path with minimum dynamic disturbance.

Breaking waves and the equilibrium range of wind-wave spectra

1997 ◽  
Vol 342 ◽  
pp. 377-401 ◽  
Author(s):  
S. E. BELCHER ◽  
J. C. VASSILICOS
Keyword(s):  
High Frequency ◽  
Wind Wave ◽  
Breaking Waves ◽  
Breaking Wave ◽  
Wave Spectra ◽  
Scale Invariant ◽  
Self Similar ◽  
Dynamical Properties ◽  
Dynamical Balance ◽  
Equilibrium Range

When scaled properly, the high-wavenumber and high-frequency parts of wind-wave spectra collapse onto universal curves. This collapse has been attributed to a dynamical balance and so these parts of the spectra have been called the equilibrium range. We develop a model for this equilibrium range based on kinematical and dynamical properties of breaking waves. Data suggest that breaking waves have high curvature at their crests, and they are modelled here as waves with discontinuous slope at their crests. Spectra are then dominated by these singularities in slope. The equilibrium range is assumed to be scale invariant, meaning that there is no privileged lengthscale. This assumption implies that: (i) the sharp-crested breaking waves have self-similar shapes, so that large breaking waves are magnified copies of the smaller breaking waves; and (ii) statistical properties of breaking waves, such as the average total length of breaking-wave fronts of a given scale, vary with the scale of the breaking waves as a power law, parameterized here with exponent D.

Nonlinear Dynamic Characteristics of Giant Magnetostrictive Nanofilm-SMA Composite Beam in Axial Stochastic Excitation

2013 ◽  
Vol 284-287 ◽  
pp. 173-177
Author(s):  
Zhi Wen Zhu ◽  
Wei Guo ◽  
Jia Xu
Keyword(s):  
Probability Density Function ◽  
Probability Density ◽  
Density Function ◽  
Dynamic Characteristics ◽  
Nonlinear Dynamic ◽  
Composite Beam ◽  
Stochastic Bifurcation ◽  
Hysteresis Phenomenon ◽  
Stochastic Excitation ◽  
Nonlinear Dynamic Characteristics

In this paper, nonlinear dynamic characteristics of giant magnetostructive nanofilm-shape memory alloy (SMA) composite beam in axial stochastic excitation were studied. Von del Pol nonlinear difference item was introduced to interpret the hysteresis phenomenon of the strain-stress curve of SMA, and the hysteretic nonlinear dynamic model of giant magnetostructive nanofilm-SMA composite beam in axial stochastic excitation was developed. The steady-state probability density function and the joint probability density function of the system were obtained in quasi-nonintegrable Hamiltonian system theory. The result of simulation shows that the stability of the trivial solution varies with bifurcation parameter, and stochastic Hopf bifurcation appears in the process. The result is helpful to stochastic bifurcation control to giant magnetostructive nanofilm-SMA composite beam.

Design and Analysis of Suspension Scheme for Space Manipulator Low-Gravity Test

2014 ◽  
Vol 940 ◽  
pp. 321-326
Author(s):  
Wei Feng ◽  
Wang Min Yi ◽  
Fan Wei Meng ◽  
Xiao Peng Shen ◽  
Xiao Dong Song
Keyword(s):  
Theoretical Analysis ◽  
Optimal Location ◽  
Motion Path ◽  
Test Results ◽  
Low Gravity ◽  
Space Manipulator ◽  
Experimental Scheme ◽  
Space Manipulators ◽  
Gravity Test

In this paper, a low gravity experimental scheme with weight-balanced suspenders is proposed to solve the problem of the low-gravity environments simulation for the space manipulators (SM), in which the optimal location of the hanging point can be obtained from theoretical analysis. In addition, according to low gravity experiment requirement and motion path of the SM, the kinematical equation in terms of D-H method is built, the suspender adaptability under horizontal and inclined conditions are studied respectively using MATLAB, and a solution for suspender interference is proposed and verified. The test results confirmed the validity of the proposed scheme.

scholarly journals Specifications of Resonant Acoustic Rotating Waves in Circular and Annular Domains

2020 ◽  
Vol 19 ◽  
Keyword(s):  
High Frequency ◽  
Low Frequency ◽  
Modern Technology ◽  
Frequency Region ◽  
High Frequency Region ◽  
Rotating Waves ◽  
Vibration Properties ◽  
Frequency Branch ◽  
Angular Velocities ◽  
Annular Domains

Circular and annular domains of hydroacoustic vibration are very common in modern technology due to their simplicity. On the other hand it turns out that such a shape possesses remarkable vibration properties. It is determined that there are two classes of resonant rotating waves, predominantly tangential and predominantly radial, in terms of prevalence of tangential or radial components of the vectors of vibrational velocities and displacements. The complete map of resonant angular velocities shows that all predominantly tangential angular velocities for all values of ring thickness are assembled into the self-isolating unique single low-frequency branch, whereas predominantly radial ones fill the entire high-frequency region very densely.

scholarly journals Estimation of Vibration Characteristics of a Space Manipulator From Air Bearing Supported Test Data

2021 ◽  
Vol 8 ◽  
Author(s):  
Haiquan Li ◽  
Qingqing Wei ◽  
Jianxun Liang ◽  
Weiyan Ren ◽  
Zixin Tang ◽  
...  
Keyword(s):  
Test Data ◽  
Joint Stiffness ◽  
Test System ◽  
Vibration Characteristics ◽  
Air Bearing ◽  
Air Bearings ◽  
Space Manipulator ◽  
Space Manipulators ◽  
Ground Test ◽  
Stiffness And Damping

Space manipulators have attracted much attention due to their implications in on-orbit servicing in recent years. Air bearing based support equipment is widely used for ground test to offset the effect of gravity. However, an air bearing support introduces a new problem caused by additional inertial and mass properties. Additional mass and inertial load will influence the dynamics behavior, especially stiffness information and vibration response of the whole ground test system. In this paper, a set of procedures are presented to remove the influence of air bearings and identify the true equivalent joint stiffness and damping from the test data of a motor-braked space manipulator with an air bearing support. First, inertia parameters are identified. Then, the equivalent joint stiffness and damping are determined by using a genetic algorithm (GA) method. Finally, true vibration characteristics of the manipulator are estimated by removing the additional inertia caused by the air bearings. Moreover, simulations and experiments are carried out to validate the presented procedures.

Dynamical models of high-frequency data analysis

2007 ◽  
Vol 177 (1-2) ◽  
pp. 187
Author(s):  
Gyuchang Lim ◽  
Soo Yoo Kim ◽  
Ji-Hyun Kang ◽  
Kyungsik Kim
Keyword(s):  
Data Analysis ◽  
High Frequency ◽  
High Frequency Data ◽  
Frequency Data ◽  
Dynamical Models
Sign in / Sign up

Export Citation Format

Share Document