On Dynamics and Control of Multi-Link Flexible Manipulators

1995 ◽  
Vol 117 (2) ◽  
pp. 134-142 ◽  
Author(s):  
W. Gawronski ◽  
C.-H. C. Ih ◽  
S. J. Wang
Keyword(s):  
Rigid Body ◽  
Inverse Dynamics ◽  
Linear Time ◽  
Flexible Manipulator ◽  
Flexible Manipulators ◽  
Link Length ◽  
Joint Torques ◽  
Control Approach ◽  
Dynamics And Control ◽  
And Control

This paper presents solutions of dynamics, inverse dynamics, and control problems of multi-link flexible manipulators. In deriving the manipulator dynamics, flexible deformations are assumed to be small in relation to the link length, angular rates of the links are assumed to be much smaller than their fundamental frequencies, and nonlinear terms (centrifugal and Coriolis forces) in the flexible manipulator model are assumed to be the same as those in the rigid body model. Flexible displacements are measured with respect to the rigid body configuration, obtained from its rigid body inverse kinematics. As a result, a linear time-varying system is obtained. The inverse dynamics problem consists of determination of joint torques for a given tip trajectory such that joint angles in the flexible configuration are equal to the angles in the rigid body configuration. The manipulator control system consists of the feedforward compensation and feedback control loops. Simulation results of a two-link space crane with a large payload show that the performance of this linearized dynamics and control approach is accurate, and at the same time is robust when subjected to parameter variations during slew operations.

Electrospinning Nanofibers: Measurements, Dynamics, and Control Strategy Development

2014 ◽  
Author(s):  
Yunshen Cai ◽  
Michael Gevelber
Keyword(s):  
Controller Design ◽  
Fiber Diameter ◽  
Operating Regime ◽  
Strategy Development ◽  
Process Conditions ◽  
Control Approach ◽  
Process Dynamics ◽  
Wide Range ◽  
Dynamics And Control ◽  
And Control

Electrospinning produces submicron fibers for a variety of applications using a wide range of polymers. Achieving the desired fiber diameter, maximizing productivity, and minimizing variation are important production objectives. This paper addresses several important areas needed to develop a general electrospinning control approach including: developing a correlation between measurements, process conditions, and the resulting fiber diameter, developing a method to determine an operating regime that meets manufacturing objectives, and identifying process dynamics for controller design.

Dynamics and Control of a Helicopter Carrying a Payload Using a Cable-Suspended Robot

2005 ◽  
Author(s):  
So-Ryeok Oh ◽  
Ji-Chul Ryu ◽  
Sunil K. Agrawal
Keyword(s):  
Control Method ◽  
Dual System ◽  
Robust Controller ◽  
Robot System ◽  
Control Approach ◽  
Cable Robot ◽  
Dynamics And Control ◽  
Position And Orientation ◽  
And Control ◽  
Scale Control

This paper presents a study of the dynamics and control of a helicopter carrying a payload through a cable-suspended robot. The helicopter can perform gross motion, while the cable suspended robot underneath the helicopter can modulate a platform in position and orientation. Due to the under-actuated nature of the helicopter, the operation of this dual system consisting of the helicopter and the cable robot is challenging. We propose here a two time scale control method, which makes it possible to control the helicopter and the cable robot independently. In addition, this method provides an effective estimation on the bound of the motion of the helicopter. Therefore, even in the case where the helicopter motion is unknown, the cable robot can be stabilized by implementing a robust controller. Simulation results of the dual system show that the proposed control approach is effective for such a helicopter-robot system.

Dynamics and control of capture of a floating rigid body by a spacecraft robotic arm

2014 ◽  
Vol 33 (3) ◽  
pp. 315-332 ◽  
Author(s):  
Xiao-Feng Liu ◽  
Hai-Quan Li ◽  
Yi-Jun Chen ◽  
Guo-Ping Cai ◽  
Xi Wang
Keyword(s):  
Rigid Body ◽  
Robotic Arm ◽  
Dynamics And Control ◽  
And Control

scholarly journals A unified approach to rigid body rotational dynamics and control

2011 ◽  
Vol 468 (2138) ◽  
pp. 395-414 ◽  
Author(s):  
Firdaus E. Udwadia ◽  
Aaron D. Schutte
Keyword(s):  
Rigid Body ◽  
Closed Form ◽  
Equations Of Motion ◽  
Fundamental Equation ◽  
Rotational Dynamics ◽  
Constrained Motion ◽  
Dynamics And Control ◽  
Common Framework ◽  
The Stability ◽  
And Control

This paper develops a unified methodology for obtaining both the general equations of motion describing the rotational dynamics of a rigid body using quaternions as well as its control. This is achieved in a simple systematic manner using the so-called fundamental equation of constrained motion that permits both the dynamics and the control to be placed within a common framework. It is shown that a first application of this equation yields, in closed form, the equations of rotational dynamics, whereas a second application of the self-same equation yields two new methods for explicitly determining, in closed form, the nonlinear control torque needed to change the orientation of a rigid body. The stability of the controllers developed is analysed, and numerical examples showing the ease and efficacy of the unified methodology are provided.

scholarly journals Dynamic analysis of two-link flexible manipulator considering the link length ratio and the payload

2017 ◽  
Vol 39 (4) ◽  
pp. 303-313
Author(s):  
Duong Xuan Bien ◽  
Chu Anh My ◽  
Phan Bui Khoi
Keyword(s):  
Mechanical Design ◽  
Flexible Manipulator ◽  
Length Ratio ◽  
Elastic Displacement ◽  
Design Parameters ◽  
Nonlinear Dynamic Model ◽  
Link Length ◽  
Modeling And Analysis ◽  
Robot Systems ◽  
And Control

Dynamic modeling and analysis of flexible manipulators play an essential role in optimizing mechanical design parameters and control law of real robot systems. In this paper, a nonlinear dynamic model of a manipulator is formulated based on the Finite Element Method. To analyze the dynamic behavior effectively, a numerical simulation scheme is proposed by taking full advantages of MATLAB and SIMULINK toolboxes. In this manner, the effect of varying payload and link length ratio of the manipulator to its elastic displacement is dynamically taken into account. The simulation results show that the payload and length link ratio have significant influences on the elastic displacements of the system. In particular, a proper spectrum of the link length ratio, in which the flexural displacement of the end point of the manipulator is smallest, is demonstrated. To this end, the proposed methodology could be used further to select optimal geometric parameters for the links of new robot designs.

Experimental Validation of a Dynamic Model (Equivalent Rigid Link System) on a Single-Link Flexible Manipulator

1989 ◽  
Vol 111 (4) ◽  
pp. 667-672 ◽  
Author(s):  
R. P. Petroka ◽  
Liang-Wey Chang
Keyword(s):  
Dynamic Model ◽  
Robot Manipulator ◽  
Flexible Manipulator ◽  
Flexible Manipulators ◽  
Rigid Link ◽  
Future Design ◽  
Single Link ◽  
Manipulator Design ◽  
And Control ◽  
Improved Accuracy

Flexibility effects on robot manipulator design and control are typically ignored which is justified when large, bulky robotic mechanisms are moved at slow speeds. However, when increased speed and improved accuracy are desired in robot system performance it is necessary to consider flexible manipulators. This paper simulates the motion of a single-link, flexible manipulator using the Equivalent Rigid Link System (ERLS) dynamic model and experimentally validates the computer simulation results. Validation of the flexible manipulator dynamic model is necessary to ensure confidence of the model for use in future design and control applications of flexible manipulators.

scholarly journals Stabilization of a Rigid Body Payload With Multiple Cooperative Quadrotors

2016 ◽  
Vol 138 (12) ◽  
Author(s):  
Farhad A. Goodarzi ◽  
Taeyoung Lee
Keyword(s):  
Rigid Body ◽  
Arbitrary Number ◽  
Equations Of Motion ◽  
Vertical Direction ◽  
Free Form ◽  
Nonlinear Controller ◽  
Dynamics And Control ◽  
And Control ◽  
Flexible Cables ◽  
Quadrotor Unmanned Aerial Vehicles

Abstract This paper presents the full dynamics and control of arbitrary number of quadrotor unmanned aerial vehicles (UAVs) transporting a rigid body. The rigid body is connected to the quadrotors via flexible cables where each flexible cable is modeled as a system of arbitrary number of serially connected links. It is shown that a coordinate-free form of equations of motion can be derived for the complete model without any simplicity assumptions that commonly appear in other literature, according to Lagrangian mechanics on a manifold. A geometric nonlinear controller is presented to transport the rigid body to a fixed desired position while aligning all of the links along the vertical direction. A rigorous mathematical stability proof is given and the desirable features of the proposed controller are illustrated by numerical examples and experimental results.

Conservation Laws -- a Source for Distortionless Propagation and Time Delays

2021 ◽  
Vol 1 (2) ◽  
pp. 1-11
Author(s):  
Vladimir Rasvan
Keyword(s):  
Conservation Laws ◽  
Transmission Lines ◽  
Time Delays ◽  
Functional Equations ◽  
Neutral Type ◽  
Initial Boundary ◽  
Hyperbolic Partial Differential Equations ◽  
Control Approach ◽  
Dynamics And Control ◽  
And Control

Since the very first paper of J. Bernoulli in 1728, a connection exists between initial boundary value problems for hyperbolic Partial Differential Equations (PDE) in the plane (with a single space coordinate accounting for wave propagation) and some associated Functional Equations (FE). From the point of view of dynamics and control (to be specific, of dynamics for control) both type of equations generate dynamical and controlled dynamical systems. The functional equations may be difference equations (in continuous time), delay-differential (mostly of neutral type) or even integral/integro-differential. It is possible to discuss dynamics and control either for PDE or FE since both may be viewed as self contained mathematical objects. A more recent topic is control of systems displaying conservation laws. Conservation laws are described by  nonlinear hyperbolic PDE belonging to the class ``lossless'' (conservative); their dynamics and control theory is well served by the associated energy integral. It is however not without interest to discuss association of some FE. Lossless implies usually distortionless propagation hence one would expect here also lumped time delays. The paper contains some illustrating applications from various fields: nuclear reactors with circulating fuel, canal flows control, overhead crane, drilling devices, without forgetting the standard classical example of the nonhomogeneous transmission lines for distortionless and lossless propagation. Specific features of the control models are discussed in connection with the control approach wherever it applies.

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