Passivity and Noncollocation in the Control of Flexible Multibody Systems

1999 ◽  
Vol 122 (1) ◽  
pp. 11-17 ◽  
Author(s):  
Christopher J. Damaren
Keyword(s):  
Experimental Study ◽  
Multibody Systems ◽  
Flexible Structures ◽  
Robotic Manipulation ◽  
Control Problems ◽  
Vibration Modes ◽  
Stabilization Problem ◽  
Input Output ◽  
Mass Properties ◽  
Adaptive Feedforward

Collocation of actuation and sensing in flexible structures leads to the desirable input-output property of passivity which greatly simplifies the stabilization problem. However, many control problems of interest such as robotic manipulation are noncollocated in nature. This paper examines the possibility of combining collocated and noncollocated outputs so as to achieve passivity. An appropriate combination is shown to depend on the interplay between collocated and noncollocated mass properties. Tracking problems are also studied and a controller with adaptive feedforward elements is introduced. An experimental study using a simple flexible apparatus with one rigid degree of freedom and two vibration modes is used to validate the analysis. [S0022-0434(00)01701-9]

Piezoelectric Devices for Vibration Control on Flexible Structures

1991 ◽  
Author(s):  
I. Legrain ◽  
P. Destuynder
Keyword(s):  
Experimental Study ◽  
Vibration Control ◽  
Closed Loop ◽  
Flexible Structures ◽  
Vibration Modes ◽  
Piezoelectric Devices

Abstract A coupled numerical and experimental study, concerning the vibration control, on flexible structures by piezoelectric devices, is presented in this paper. More precisely we studied two cases of structure, a beam and a plate, in several configurations of excitation. The implemented controls, which are closed loop controls, concern always the first vibration modes.

Force Feedback in Adaptive Trusses for Vibration Isolation in Flexible Structures

1997 ◽  
Vol 119 (3) ◽  
pp. 365-371 ◽  
Author(s):  
W. W. Clark ◽  
H. H. Robertshaw
Keyword(s):  
Vibration Isolation ◽  
Force Feedback ◽  
Flexible Structures ◽  
Control Law ◽  
Control Problems ◽  
Sensors And Actuators ◽  
Dynamic Forces ◽  
Active Vibration ◽  
The Ideal

This paper addresses the transmission of unwanted vibrations in flexible structures by actively minimizing dynamic forces seen at critical locations within the structure. An adaptive truss serves as an active interface between the two isolated sides of the structure, and force-feedback within individual links of the truss is the governing control law. The use of an adaptive truss allows the problem to be viewed as a set of localized control problems with collocated sensors and actuators. This paper first discusses the ideal capabilities of force feedback for active vibration isolation, and then presents the analytical and experimental results of a case study which shows significant reduction in transmitted vibrations.

Parameter Analysis and Normalization for the Dynamics and Design of Multibody Systems

2009 ◽  
Vol 4 (3) ◽  
Author(s):  
József Kövecses ◽  
Saeed Ebrahimi
Keyword(s):  
Parameter Estimation ◽  
Multibody Systems ◽  
Eigenvalue Problems ◽  
Physical Structure ◽  
Parameter Analysis ◽  
Control Problems ◽  
Inertial Parameters ◽  
Parametric Studies ◽  
Novel Concept ◽  
And Control

In this paper, we introduce a novel concept for parametric studies in multibody dynamics. This includes a technique to perform a natural normalization of the dynamics in terms of inertial parameters. This normalization technique rises out from the underlying physical structure of the system and the trajectory investigated. This structure is mathematically expressed in the form of eigenvalue problems. It leads to the introduction of the concept of dimensionless inertial parameters. This, in turn, makes it possible to introduce an analysis approach for studying design and control problems where parameter estimation and sensitivity are of importance.

scholarly journals A Recursive Multibody Dynamics and Sensitivity Algorithm for Branched Kinematic Chains

2000 ◽  
Vol 123 (3) ◽  
pp. 391-399 ◽  
Author(s):  
Garett A. Sohl ◽  
James E. Bobrow
Keyword(s):  
Lie Algebras ◽  
Multibody Systems ◽  
Optimal Control Problems ◽  
Underactuated Systems ◽  
Control Problems ◽  
Simulation Tool ◽  
Kinematic Chains ◽  
Walking Machines ◽  
Sensitivity Equations ◽  
Wide Range

In this work an efficient dynamics algorithm is developed, which is applicable to a wide range of multibody systems, including underactuated systems, branched or tree-topology systems, robots, and walking machines. The dynamics algorithm is differentiated with respect to the input parameters in order to form sensitivity equations. The algorithm makes use of techniques and notation from the theory of Lie groups and Lie algebras, which is reviewed briefly. One of the strengths of our formulation is the ability to easily differentiate the dynamics algorithm with respect to parameters of interest. We demonstrate one important use of our dynamics and sensitivity algorithms by using them to solve difficult optimal control problems for underactuated systems. The algorithms in this paper have been implemented in a software package named Cstorm (Computer simulation tool for the optimization of robot manipulators), which runs from within Matlab and Simulink. It can be downloaded from the website http://www.eng.uci.edu/∼bobrow/

Controlling Vibration in Remote Manipulators

1987 ◽  
Author(s):  
N. C. Singer ◽  
W. P. Seering
Keyword(s):  
Space Shuttle ◽  
Feedforward Control ◽  
Vibration Reduction ◽  
Flexible Structures ◽  
Robotic Manipulators ◽  
Control Problems ◽  
Software Model ◽  
Modes Of Vibration ◽  
Vibrational Characteristics ◽  
Special Control

Abstract Robotic manipulators for use in space have flexible structures and as a result have special control problems. These manipulators change their vibrational characteristics as they change in orientation. The Space Shuttle Remote Manipulator System (RMS) was chosen as a typical system and experiments were performed using the Draper Laboratory software model of the arm (DRS). First, the workspace of the manipulator was characterized in terms of the robot’s first two modes of vibration. Next, some feedforward experiments were performed on the computer model to show the promise of vibration reduction using feedforward control.

EXPERIMENTAL STUDY OF DYNAMIC PARAMETERS OF COMPLEX PIPELINE SYSTEM

Akustika ◽  
2021 ◽  
pp. 65-72
Author(s):  
Antonina Sekacheva ◽  
Lilia Pastukhova ◽  
Alexandr Noskov
Keyword(s):  
Experimental Study ◽  
Natural Frequencies ◽  
Stationary Process ◽  
Spatial Configuration ◽  
Dynamic Processes ◽  
Pipeline System ◽  
Vibration Modes ◽  
Dynamic Parameters ◽  
Frequency Range ◽  
Pump Operation

The article discusses the results of studies of the dynamic parameters of a pipeline connected to a pump, carried out in order to obtain data in full-scale conditions. At this stage of the study, the stationary process of the pump operation, which forms a turbulent flow in the pipeline, was studied. A computational and experimental technique for studying natural frequencies and vibration modes of pipelines of complex spatial configuration has been developed. The adequacy of the developed methods of finite element modeling of dynamic processes in pipeline systems in the frequency range up to 400 Hz has been confirmed.

New Component Modes for Flexible Multibody Systems

1997 ◽  
Author(s):  
O. Verlinden ◽  
P. Dehombreux ◽  
C. Conti
Keyword(s):  
Boundary Conditions ◽  
Multibody Systems ◽  
Flexible Body ◽  
Vibration Modes ◽  
Large Displacements ◽  
Natural Boundary ◽  
Body Reference ◽  
Natural Boundary Conditions ◽  
Deformation Modes ◽  
Classical Mode

Abstract In multibody systems, the deformation of a flexible body is generally modelled by a weighted summation of previously chosen deformation modes. Mode sets composed of static and vibration modes, which proved efficient in structural analysis, are commonly used in practice. The paper presents how the classical reductions can be adapted to better fit the peculiarities of multibody systems. It is first shown how the classical mode sets can be reorganized according to the particular kinematics of a flexible body, based on a body reference frame. Secondly, it is proposed to add acceleration modes to the classical reductions to better represent the deformation during large displacements. The importance of natural boundary conditions in multibody systems is also emphasized. The benefit of the acceleration modes and the interest of coherent natural boundary conditions are illustrated on the example of a railway engine, for two different analyses, by means of an expressly developed quality test.

Position and Force Control of Multibody Systems by Feedback Linearization

1992 ◽  
Author(s):  
Christoph Woernle
Keyword(s):  
Force Control ◽  
Multibody Systems ◽  
Feedback Linearization ◽  
Linearization Method ◽  
Robotic Systems ◽  
Input Output ◽  
Internal Dynamics ◽  
Constrained Multibody Systems ◽  
Walking Machines ◽  
Controlled Motion

Abstract A unified formulation of the feedback linearization method to the hybrid position and force control of constrained multibody systems is developed. Similar to the feedback linearization of unconstrained systems, linear decoupled input-output channels for position and force control variables, which can be controlled separately, and a nonlinear nonobservable internal dynamics are obtained. Technical applications are robotic systems with multiple, interacting arms, multifingered grippers grasping an object, mechanisms with controlled motion, or walking machines.

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