Development of a Laser Based Dual-Axial Five-Degrees-of-Freedom Measurement System for an X-Y Stage

2006 ◽  
Author(s):  
Wen-Yuh Jywe ◽  
Chien Hung Liu ◽  
Yun-Feng Teng ◽  
Chun-Jen Chen ◽  
Jing-Chung Shen ◽  
...  
Keyword(s):  
Measurement System ◽  
Simultaneous Measurement ◽  
Degrees Of Freedom ◽  
Laser Interferometer ◽  
Optical Path ◽  
Degree Of Freedom ◽  
Position Errors ◽  
The One ◽  
Three Degree Of Freedom ◽  
Error Verification

This paper presents a new precision multi-DOF measurement system which has been developed and implemented for the simultaneous measurement of 5DOF motion errors (two linear positions, as well as pitch, roll and yaw) of an X-Y stage. In this paper, the 3DOF laser interferometer was produced by designing the optical path from the one-degrees-of-freedom laser interferometer. The system employs two three-degree-of-freedom interferometers to detect two position errors and three angular errors of the X-Y stage. The experimental setups and measuring procedure and a systematic calculated method for the error verification are presented in the paper. The resolution of measuring the angular errors component is about 0.055 arcsec.

Design of a Teaching Robot with Three Degrees of Freedom

2012 ◽  
Vol 619 ◽  
pp. 325-328
Author(s):  
You Jun Huang ◽  
Ze Lun Li ◽  
Zhi Cheng Huang
Keyword(s):  
Degrees Of Freedom ◽  
Low Cost ◽  
Degree Of Freedom ◽  
Good Repeatability ◽  
Main Components ◽  
Opening And Closing ◽  
Three Degree Of Freedom ◽  
Three Degrees Of Freedom ◽  
Application Prospects

A teaching robot with three degree of freedom is designed. The three degrees of freedom are: waist rotation, lifting and stretching of the arm and opening and closing of the gripper. The designs of the main components are: a mobile chassis, parallel rails, horizontal rails and manipulator. The teaching robot designed has the features of low cost, easy to regulation, good repeatability and it has good promotion and application prospects in the field of teaching.

Rudder/Fin Roll Stabilization of the USCG WMEC 901 Class Vessel

1999 ◽  
Vol 36 (03) ◽  
pp. 157-170
Author(s):  
Jerrold N. Sgobbo ◽  
Michael G. Parsons
Keyword(s):  
Degrees Of Freedom ◽  
Multiple Input Multiple Output ◽  
Cross Coupling ◽  
Degree Of Freedom ◽  
Rolling Motion ◽  
Rolling Moment ◽  
Multiple Input ◽  
Input Multiple Output ◽  
Three Degree Of Freedom ◽  
The U.S

The U.S. Coast Guard's 270-ft Medium Endurance Cutter (WMEC) operates with an active fin stabilization system. This system was designed using a one-degree-of-freedom (1-DOF) model in the roll direction. The controller was designed separate from the heading autopilot. The effects of the rudders and their ability to produce a significant rolling moment were also neglected as well as the cross coupling of roll motions into other degrees of freedom. This paper studies the effects of the rudders on the rolling motion of the ship using a three-degree-of-freedom (3-DOF) model. A simple optimal heading autopilot is designed and combined with the existing fin roll controller to investigate the effects of the rudders on the roll motions of this class of vessel. A rudder roll controller and a multiple input-multiple output (MIMO) rudder/fin controller are designed as well. Significant roll reduction can be achieved using the MIMO rudder/fin controller.

scholarly journals Compact Laser Collimation System for Simultaneous Measurement of Five-Degree-of-Freedom Motion Errors

2020 ◽  
Vol 10 (15) ◽  
pp. 5057
Author(s):  
Chuang Sun ◽  
Sheng Cai ◽  
Yusheng Liu ◽  
Yanfeng Qiao
Keyword(s):  
Simultaneous Measurement ◽  
Measurement Accuracy ◽  
Measurement Data ◽  
Optical Path ◽  
Degree Of Freedom ◽  
Experimental Setup ◽  
Collimation System ◽  
Optical Configuration ◽  
Series Of Experiments ◽  
The Common

A compact laser collimation system is presented for the simultaneous measurement of five-degree-of-freedom motion errors. The optical configuration of the proposed system is designed, and the principle of the measurement of five-degree-of-freedom errors is described in detail. The resolution of the roll and the horizontal straightness is doubled compared with other laser collimation methods. A common optical path compensation method is provided to detect light drift in real time and compensate for straightness and angle errors. An experimental setup is constructed, and a series of experiments are performed to verify the feasibility and stability of the system. Compared with commercial instruments, the pitch and yaw residuals are ± 2.5 ″ and ± 3.5 ″ without correction, and the residuals are ± 1.9 ″ and ± 2.8 ″ after correction, respectively. The comparison deviations of the horizontal straightness and vertical straightness changed from ± 4.8   μ m to ± 2.8 μm and ± 5.9 μm to ± 3.6 μm, respectively. The comparison deviation of the roll is ± 4.3 ″ . The experimental results show that the data of the five-degree-of-freedom measurement system obtained are largely the same as the measurement data of commercial instruments. The common optical path compensation can effectively improve the measurement accuracy of the system.

scholarly journals Feedback Linearisation for Nonlinear Vibration Problems

2014 ◽  
Vol 2014 ◽  
pp. 1-16 ◽  
Author(s):  
S. Jiffri ◽  
P. Paoletti ◽  
J. E. Cooper ◽  
J. E. Mottershead
Keyword(s):  
Degrees Of Freedom ◽  
Nonlinear Problems ◽  
Second Order ◽  
Degree Of Freedom ◽  
Sensors And Actuators ◽  
Order Matrix ◽  
Problem Class ◽  
Aeroelastic Model ◽  
Matrix Differential ◽  
Three Degree Of Freedom

Feedback linearisation is a well-known technique in the controls community but has not been widely taken up in the vibrations community. It has the advantage of linearising nonlinear system models, thereby enabling the avoidance of the complicated mathematics associated with nonlinear problems. A particular and common class of problems is considered, where the nonlinearity is present in a system parameter and a formulation in terms of the usual second-order matrix differential equation is presented. The classical texts all cast the feedback linearisation problem in first-order form, requiring repeated differentiation of the output, usually presented in the Lie algebra notation. This becomes unnecessary when using second-order matrix equations of the problem class considered herein. Analysis is presented for the general multidegree of freedom system for those cases when a full set of sensors and actuators is available at every degree of freedom and when the number of sensors and actuators is fewer than the number of degrees of freedom. Adaptive feedback linearisation is used to address the problem of nonlinearity that is not known precisely. The theory is illustrated by means of a three-degree-of-freedom nonlinear aeroelastic model, with results demonstrating the effectiveness of the method in suppressing flutter.

Inertial Vibration Damping Control for a Flexible Base Manipulator

2002 ◽  
Author(s):  
Lynnane E. George ◽  
Wayne J. Book
Keyword(s):  
Performance Index ◽  
Degrees Of Freedom ◽  
Position Control ◽  
Joint Space ◽  
Vibration Damping ◽  
Degree Of Freedom ◽  
Inertia Effects ◽  
Inertial Interaction ◽  
Flexible Base ◽  
Three Degree Of Freedom

A rigid (micro) robot mounted serially to the tip of a long, flexible (macro) manipulator is often used to increase reach capability, but flexibility in the macromanipulator can interfere with positioning accuracy. A rigid manipulator attached to a flexible but unactuated base was used to study a scheme to achieve positioning of the micromanipulator combined with enhanced vibration damping of the base. Inertial interaction forces and torques acting between the robot and its base were modeled and studied to determine how to use them to damp the vibration. One issue is that there are locations in the workspace where the rigid robot loses its ability to create interactions in one or more degrees of freedom. These “inertial singularities” are functions of the rigid robot’s joint variables. A performance index was developed to predict the ability of the rigid robot to damp vibration and will help ensure the robot is operating in joint space configurations favorable for inertial damping. When the performance index is used along with the appropriate choice of feedback gains, the inertia effects, or those directly due to accelerating the robot’s links, have the greatest influence on the interactions. By commanding the robot link’s accelerations out of phase with the base velocity, vibration energy will be removed from the system. This signal is then added to the rigid robot’s position control signal. Simulations of a rigid three degree of freedom anthropomorphic robot mounted on a flexible base were developed and show the effectiveness of the control scheme. In addition, experimental results demonstrating two degree of freedom vibration damping are included.

scholarly journals A Global Approach for Using Kinematic Redundancy to Minimize Base Reactions of Manipulators

1989 ◽  
Author(s):  
C. L. Chung ◽  
S. Desa
Keyword(s):  
Degrees Of Freedom ◽  
Degree Of Freedom ◽  
Redundancy Resolution ◽  
Global Approach ◽  
Local Approach ◽  
Time Integral ◽  
Point Motion ◽  
Point To Point ◽  
The Moment ◽  
Three Degree Of Freedom

Abstract An important consideration in the use of manipulators in Microgravity environments is the minimization of the base reactions, i.e. the magnitude of the force and the moment exerted by the manipulator on its base as it performs its tasks. One approach which has been proposed and implemented is to use the redundant degrees of freedom in a kinematically redundant manipulator to plan manipulator trajectories to minimize base reactions. In this paper we develop a global approach for minimizing the magnitude of the base reactions for kinematically redundant manipulators which integrates the Partitioned Jacobian method of redundancy resolution, a 4-3-4 joint-trajectory representation and the minimization of a cost function which is the time-integral of the magnitude of the base reactions. We also compare the global approach with a local approach developed earlier for the case of point-to-point motion of a three degree-of-freedom planar manipulator with one redundant degree-of-freedom. The results of study show that the global approach is more effective in reducing and smoothing the base force while the local approach is superior in reducing the base moment.

Three-degree-of-freedom micro-vibration measurement system based on dual-frequency laser interference

2019 ◽  
Vol 27 (7) ◽  
pp. 1435-1443
Author(s):  
陈家键 CHEN Jia-jian ◽  
胡慧珠 HU Hui-zhu ◽  
缪立军 MIAO Li-jun ◽  
周一览 ZHOU Yi-lan ◽  
舒晓武 SHU Xiao-wu
Keyword(s):  
Measurement System ◽  
Degree Of Freedom ◽  
Vibration Measurement ◽  
Dual Frequency ◽  
Laser Interference ◽  
Frequency Laser ◽  
Micro Vibration ◽  
Three Degree Of Freedom

Modeling and Experimental Evaluation of Asymmetric Pantograph Dynamics

1988 ◽  
Vol 110 (2) ◽  
pp. 168-174 ◽  
Author(s):  
S. D. Eppinger ◽  
D. N. O’Connor ◽  
W. P. Seering ◽  
D. N. Wormley
Keyword(s):  
High Performance ◽  
Degrees Of Freedom ◽  
Dynamic Models ◽  
Dynamic Testing ◽  
Dynamic Performance ◽  
Performance Model ◽  
Degree Of Freedom ◽  
Additional Degree ◽  
Three Degree Of Freedom ◽  
Two Degree Of Freedom

High-performance pantograph design requires control of pantograph dynamic performance. Many pantograph dynamic models developed to aid in the design process have employed two degrees of freedom, one for the head mass and one for the frame. In this paper, the applicability of these models to symmetric and asymmetric pantograph designs is reviewed. Two degree-of-freedom models have been shown to be appropriate to represent a number of symmetric pantograph designs. To represent the asymmetric designs considered in this paper, an additional degree of freedom representing frame dynamics has been introduced to yield a three degree-of-freedom nonlinear dynamic performance model. The model has been evaluated with experimental data obtained from laboratory dynamic testing of an asymmetric pantograph.

On the Lateral Stability and Control of the Automobile as Influenced by the Dynamics of the Steering System

1966 ◽  
Vol 88 (3) ◽  
pp. 283-294 ◽  
Author(s):  
Leonard Segel
Keyword(s):  
Degrees Of Freedom ◽  
Steering System ◽  
Degree Of Freedom ◽  
Design Parameters ◽  
Steering Wheel ◽  
Directional Control ◽  
Natural Modes Of Motion ◽  
Three Degree Of Freedom ◽  
And Control ◽  
Automobile Use

Measurements of the directional response of an automobile to torque inputs applied at the steering wheel are compared with predictions yielded by a five-degree-of-freedom model of a four-wheeled, pneumatic-tired vehicle. This comparison demonstrates that the directional control and stability of the “free-control” automobile is satisfactorily characterized by the addition of a quasilinear representation of a steering system (i.e., a mechanism having two degrees of freedom with Coulomb friction introduced as the single nonlinear element) to a linear three-degree-of-freedom representation of the “fixed-control” automobile. Use is made of the experimentally substantiated five-degree-of-freedom mathematical model to study the relationship between automotive design parameters and the response and stability in each of the four natural modes of motion that exist for the free-control vehicle.

scholarly journals Hexapod with legs based on Peaucellier–Lipkin mechanisms

2018 ◽  
Vol 15 (4) ◽  
pp. 172988141879592 ◽  
Author(s):  
Ignacio Juárez-Campos ◽  
Diego A Núñez-Altamirano ◽  
Lucia Márquez-Pérez ◽  
Leonardo Romero-Muñoz ◽  
Beatriz Juárez-Campos
Keyword(s):  
Path Planning ◽  
Degrees Of Freedom ◽  
Degree Of Freedom ◽  
Mathematical Framework ◽  
Legged Robot ◽  
Specific Task ◽  
Spatial Description ◽  
Center Of Rotation ◽  
Walking Machine ◽  
The One

This article describes the way in which six nontraditional legs collaborate to provide locomotion to a walking machine when it moves along a path. Such legs are based on the one-degree-of-freedom Peaucellier–Lipkin mechanism, which was modified by the addition of four degrees of freedom. Such five-degree-of-freedom legs have the ability to adapt their postures according to the center of rotation around of which the machine walks. The attributes and abilities of the hexapod are expressed by means of a mathematical framework, which grants the spatial description and required joint variables, according to a specific task, resulting in the configuration of its legs for a particular path planning. Additionally, the article presents an illustrative example describing a detailed procedure concerning the configurations and collaboration of their legs according to an imposed center of rotation around of which the six-legged robot walks.

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