Analysis and Model-Based Control of Servomechanisms With Friction

2004 ◽  
Vol 126 (4) ◽  
pp. 911-915 ◽  
Author(s):  
Evangelos G. Papadopoulos ◽  
Georgios C. Chasparis
Keyword(s):  
Rigid Body ◽  
Function Analysis ◽  
Friction Model ◽  
Body Motion ◽  
System Response ◽  
Friction Compensation ◽  
Kinetic Friction ◽  
Motion Models ◽  
Model Based ◽  
Best Response

Friction is responsible for several servomechanism limitations, and their elimination is always a challenge for control engineers. In this paper, model-based feedback compensation is studied for servomechanism tracking tasks. Several kinetic friction models are employed and their parameters identified experimentally. The effects of friction compensation on system response are examined using describing function analysis. A number of control laws including classical laws, rigid body motion models, and friction compensation are compared experimentally in large-displacement tasks. Results show that the best response is obtained using a controller that incorporates a rigid body model and a friction model based on an accurate description of identified kinetic friction effects.

Nonlinear Model Based Estimation of Rigid-Body Motion Via an Indirect Measurement of an Elastic Appendage

2010 ◽  
Vol 132 (1) ◽  
Author(s):  
M. Senesh ◽  
A. Wolf ◽  
O. Gottlieb
Keyword(s):  
Nonlinear System ◽  
Rigid Body ◽  
Nonlinear Model ◽  
Estimation Procedure ◽  
Indirect Measurement ◽  
Body Motion ◽  
System Parameters ◽  
Model Based ◽  
Proposed Model ◽  
Linear And Nonlinear

In this paper, we develop and implement a nonlinear model based procedure for the estimation of rigid-body motion via an indirect measurement of an elastic appendage. We demonstrate the procedure by motion analysis of a compound planar pendulum from indirect optoelectronic measurements of markers attached to an elastic appendage that is constrained to slide along the rigid-body axis. We implement a Lagrangian approach to derive a theoretical nonlinear model that consistently incorporates several generalized forces acting on the system. Identification of the governing linear and nonlinear system parameters is obtained by analysis of frequency and damping backbone curves from controlled experiments of the decoupled system elements. The accuracy of the proposed model based procedures is evaluated and its results are compared with those of a previously reported point cluster estimation procedure. Two cases are investigated to yield 1.7% and 3.4% errors between measured motion and its model based estimation for experimental configurations, with a slider mass to pendulum frequency ratios of 12.8 and 2.5, respectively. Motion analysis of system dynamics with the point cluster method reveals a noisy signal with a maximal error of 3.9%. Thus, the proposed model based estimation procedure enables accurate evaluation of linear and nonlinear system parameters that are not directly measured.

Dynamic Modeling and Simulation of Flexible Robots With Prismatic Joints

1990 ◽  
Vol 112 (3) ◽  
pp. 307-314 ◽  
Author(s):  
Ye-Chen Pan ◽  
R. A. Scott ◽  
A. Galip Ulsoy
Keyword(s):  
Rigid Body ◽  
Equations Of Motion ◽  
Numerical Procedure ◽  
Differential Algebraic Equations ◽  
Rigid Body Motion ◽  
Body Motion ◽  
Integration Scheme ◽  
System Response ◽  
Constraint Equations ◽  
Prismatic Joints

A dynamic model for flexible manipulators with prismatic joints is presented in Part I of this study. Floating frames following a nominal rigid body motion are introduced to describe the kinematics of the flexible links. A Lagrangian approach is used in deriving the equations of motion. The work done by the rigid body axial force through the axial shortening of the link due to transverse deformations is included in the Lagrangian function. Kinematic constraint equations are used to describe the compatibility conditions associated with revolute joints and prismatic joints, and incorporated into the equations of motion by Lagrange multipliers. The small displacements due to the flexibility of the links are then discretized by a displacement based finite element method. Equations of motion are derived for the cases of prescribed rigid body motion as well as prescribed joint torques/forces through application of Lagrange’s equations. The equations of motion and the constraint equations result in a set of differential algebraic equations. A numerical procedure combining a constraint stabilization method and a Newmark direct integration scheme is then applied to obtain the system response. An example, previously treated in the literature, is presented to validate the modeling and solution methods used in this study.

Analysis of 3D rigid-body motion using photogrammetry: A simple model based on a mechanical analogy

2007 ◽  
Vol 75 (1) ◽  
pp. 56-61 ◽  
Author(s):  
A. Page ◽  
P. Candelas ◽  
F. Belmar ◽  
H. De Rosario
Keyword(s):  
Simple Model ◽  
Rigid Body ◽  
Rigid Body Motion ◽  
Body Motion ◽  
Mechanical Analogy ◽  
Model Based

Nonlinear Model Based Estimation of Rigid-Body Motion Via an Indirect Measurement of an Elastic Appendage

2007 ◽  
Author(s):  
M. Mor ◽  
A. Wolf ◽  
O. Gottlieb
Keyword(s):  
Rigid Body ◽  
Nonlinear Model ◽  
Rotation Angle ◽  
Estimation Procedure ◽  
Indirect Measurement ◽  
Rigid Body Motion ◽  
Body Motion ◽  
Noninvasive Methods ◽  
System Parameters ◽  
Model Based

In this paper we develop and implement a nonlinear model based procedure for estimation of rigid body motion via an indirect measurement of an elastic appendage. We demonstrate the procedure by motion analysis of a compound planar pendulum from indirect optoelectronic measurements of markers attached to an elastic appendage that is restrained to slide along the rigid-body length. We implement a Lagrangian approach to derive a theoretical nonlinear model that consistently incorporates the generalized forces acting on the system. Identification of the governing linear and nonlinear system parameters is obtained by analysis of frequency and damping backbone curves obtained from controlled experiments of the decoupled system elements. Comparison of an independently measured rotation angle to that obtained by the model-based estimation procedure enables evaluation of the procedure accuracy and its advantages over standard noninvasive methods.

A Model-Based Method for Balancing of Flexible Rotors Mounted on Oil-Film Bearings Without Trial Weight

1999 ◽  
Author(s):  
C.-P. Fritzen ◽  
P. Gans ◽  
D. Wiese ◽  
M. Breitwieser
Keyword(s):  
Rigid Body ◽  
Conservative System ◽  
Rigid Body Motion ◽  
Body Motion ◽  
Mode Shapes ◽  
Test Results ◽  
Real Motion ◽  
Oil Film ◽  
Model Based ◽  
Flexible Rotors

Abstract The following paper deals with a model-based method for unbalance identification. In contrast to conventional methods there is no need for the properties of the oil-film bearings to be known. First, the rotor is modeled as a conservative system in rigid bearings and the corresponding real mode shapes are calculated. The real motion of the rotor is represented by means of these mode shapes and the superimposed rigid-body motion of the rotor. The rigid-body motion is completely determined by the measured deflections in the oil-film bearings. Modal unbalances of the rotor are identified. Initial positive test results are presented in this paper.

scholarly journals Viscous Flow Around a Rigid Body Performing a Time-periodic Motion

2021 ◽  
Vol 23 (1) ◽  
Author(s):  
Thomas Eiter ◽  
Mads Kyed
Keyword(s):  
Rigid Body ◽  
Sobolev Spaces ◽  
Periodic Motion ◽  
Viscous Incompressible Fluid ◽  
Body Motion ◽  
Translational Velocity ◽  
Ill Posed ◽  
Homogeneous Sobolev Spaces ◽  
The Mean ◽  
Time Periodic

AbstractThe equations governing the flow of a viscous incompressible fluid around a rigid body that performs a prescribed time-periodic motion with constant axes of translation and rotation are investigated. Under the assumption that the period and the angular velocity of the prescribed rigid-body motion are compatible, and that the mean translational velocity is non-zero, existence of a time-periodic solution is established. The proof is based on an appropriate linearization, which is examined within a setting of absolutely convergent Fourier series. Since the corresponding resolvent problem is ill-posed in classical Sobolev spaces, a linear theory is developed in a framework of homogeneous Sobolev spaces.

A planar reconfigurable linear rigid-body motion linkage with two operation modes

2014 ◽  
Vol 228 (16) ◽  
pp. 2985-2991 ◽  
Author(s):  
Guangbo Hao ◽  
Xianwen Kong ◽  
Xiuyun He
Keyword(s):  
Rigid Body ◽  
Single Mode ◽  
Rigid Body Motion ◽  
Body Motion ◽  
Reference Guide ◽  
Revolute Joints ◽  
Operation Modes ◽  
Straight Line ◽  
Motion Stage ◽  
Motion Mode

A planar reconfigurable linear (also rectilinear) rigid-body motion linkage (RLRBML) with two operation modes, that is, linear rigid-body motion mode and lockup mode, is presented using only R (revolute) joints. The RLRBML does not require disassembly and external intervention to implement multi-task requirements. It is created via combining a Robert’s linkage and a double parallelogram linkage (with equal lengths of rocker links) arranged in parallel, which can convert a limited circular motion to a linear rigid-body motion without any reference guide way. This linear rigid-body motion is achieved since the double parallelogram linkage can guarantee the translation of the motion stage, and Robert’s linkage ensures the approximate straight line motion of its pivot joint connecting to the double parallelogram linkage. This novel RLRBML is under the linear rigid-body motion mode if the four rocker links in the double parallelogram linkage are not parallel. The motion stage is in the lockup mode if all of the four rocker links in the double parallelogram linkage are kept parallel in a tilted position (but the inner/outer two rocker links are still parallel). In the lockup mode, the motion stage of the RLRBML is prohibited from moving even under power off, but the double parallelogram linkage is still moveable for its own rotation application. It is noted that further RLRBMLs can be obtained from the above RLRBML by replacing Robert’s linkage with any other straight line motion linkage (such as Watt’s linkage). Additionally, a compact RLRBML and two single-mode linear rigid-body motion linkages are presented.

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