Adaptive Vibration Control for System with Friction Damping

2011 ◽  
Vol 403-408 ◽  
pp. 138-144
Author(s):  
Yong Liu ◽  
Li Hua Wen
Keyword(s):  
Adaptive Controller ◽  
Friction Model ◽  
Tracking Errors ◽  
Single Degree Of Freedom ◽  
Lugre Friction Model ◽  
Spring System ◽  
Mass Spring ◽  
Model Reference Adaptive ◽  
Velocity Tracking ◽  
Adaptive Vibration Control

The dynamic model of the single-degree-of–freedom (SDOF) mass-spring system with friction is established, based on the Lugre friction model. An observer-based model reference adaptive controller (MRAC) is proposed. By Lyapunov method, it is proved that the closed-loop system is asymptotically stable and the displacement as well as the velocity tracking errors can converge to zeros. Simulation work is carried out in both frequency and time domain. The results show that the proposed controller can greatly attenuate the response of the system significantly for both harmonic and random excitations.

Nonlinear time delay estimation based model reference adaptive impedance control for an upper-limb human-robot interaction

2021 ◽  
pp. 095441192110549
Author(s):  
Javad Omrani ◽  
Majid M Moghaddam
Keyword(s):  
Time Delay ◽  
Impedance Control ◽  
Adaptive Controller ◽  
Time Delay Estimation ◽  
Human Robot Interaction ◽  
Delay Estimation ◽  
Tracking Errors ◽  
Model Reference ◽  
Dynamic Relationship ◽  
Model Reference Adaptive

A nonlinear Time Delay Estimation (TDE) based model reference adaptive impedance controller was developed for Tarbiat Modares University Upper Limbs Rehabilitation Robot (TUERR). The proposed controller uses a stable reference impedance model, which produces desired dynamic relationship between applied force and position error for the robot End-effector to track the desired trajectory. TDE based model reference adaptive controller estimates unknown system dynamics and uncertainties, and the adaption law modifies the controller gains. Using a Lyapunov function was shown trajectory tracking errors in the overall system are bounded. In addition, a performance-based velocity profile proposed to modify the pace of trajectory planning considering the deviation from the desired path. Finally, the performance of the presented controller and rehabilitation process is experimentally investigated for TUERR.

scholarly journals Complex-Damped Dynamic Systems in the Time and Frequency Domains

2004 ◽  
Vol 11 (3-4) ◽  
pp. 209-225 ◽  
Author(s):  
Elvio Bonisoli ◽  
John E. Mottershead
Keyword(s):  
Frequency Response ◽  
Structural Dynamics ◽  
Dynamic Systems ◽  
Dynamic Behaviour ◽  
Root Locus ◽  
Single Degree Of Freedom ◽  
Single Degree ◽  
Frequency Domains ◽  
Spring System ◽  
Mass Spring

The fact that a complex-damped model may represent the dynamic behaviour of elasto-mechanical systems when acted upon by a magnetic field was brought to the attention of the structural dynamics community very recently by Professor Bruno A. D. Piombo and his colleagues at the Politecnico di Torino. In this paper a thorough analysis of the single degree-of-freedom complex-damped mass-spring system is presented. The analysis includes the root locus, the (non-causal) impulse response, the frequency response and the transmissibility. Regions of different behaviour in the frequency response and transmissibility are described in detail. The stiffening behaviour observed in Prof. Piombo's experiments and known as the "phantom effect" is demonstrated by the complex-damped model.

Prediction and Evaluation of Sensitivity to Transient Accelerations

1954 ◽  
Vol 21 (4) ◽  
pp. 371-380
Author(s):  
M. Kornhauser
Keyword(s):  
Field Measurements ◽  
Laboratory Methods ◽  
Single Degree Of Freedom ◽  
Acceleration Time ◽  
Single Degree ◽  
Spring System ◽  
Service Conditions ◽  
Sensitivity Data ◽  
Mass Spring ◽  
The Ideal

Abstract The determination, presentation, and interpretation of inertia-sensitivity data are discussed with application to inertia devices and to shock-resistant structures. Theoretical analysis of the single-degree-of-freedom system for response to acceleration-time pulses, amplification factors, and inertia sensitivity are used as a basis for discussion of actual devices. Effects of deviations from the ideal mass-spring system are considered. Practical use of sensitivity data is discussed with regard to the reliability of laboratory methods, the accuracy of field measurements, and variability of service conditions. Criteria are suggested for design of inertia mechanisms and design of structures for resistance to shock.

Unexpected Scaling of Peak Acceleration for a Yielding Mass-Spring System Subjected to a Triangular Base Acceleration Pulse

2021 ◽  
pp. 1-30
Author(s):  
Michael Guthrie
Keyword(s):  
Earthquake Engineering ◽  
Full Range ◽  
Approximate Expression ◽  
Single Degree Of Freedom ◽  
Acceleration Pulse ◽  
Relative Acceleration ◽  
Spring System ◽  
Mass Spring ◽  
Nonmonotonic Behavior ◽  
Quantities Of Interest

Abstract The use of bounding scenarios is a common practice which greatly simplifies the design and qualification of structures. However, this approach implicitly assumes that the quantities of interest increase monotonically with the input to the structure, which is not necessarily true for nonlinear structures. This paper surveys the literature for observations of nonmonotonic behavior of nonlinear systems, and finds such observations in both the earthquake engineering and applied mechanics literature. Numerical simulations of a single degree of freedom mass-spring system with an elastic-plastic spring subjected to a triangular base acceleration pulse are then presented, and it is shown that the relative acceleration of this system scales nonmonotonically with the input magnitude in some cases. The equation of motion for this system is solved symbolically and an approximate expression for the relative acceleration is developed, which qualitatively agrees with the nonmonotonic behavior seen in the numerical results. The nonmonotonicity is investigated and found to be a result of dynamics excited by the discontinuous derivative of the base acceleration pulse, the magnitude of which scales nonmonotonically with the input magnitude due to the fact that first yield of the spring occurs earlier as the input magnitude is increased. The relevance of this finding within the context of defining bounding scenarios is discussed and it is recommended that modeling be used to perform a survey of the full range of possible inputs prior to defining bounding scenarios.

On Running a Machine through its Resonant Frequency

1956 ◽  
Vol 60 (549) ◽  
pp. 620-621 ◽  
Author(s):  
J. P. Ellington ◽  
H. McCallion
Keyword(s):  
High Speed ◽  
Exciting Force ◽  
Linear Mass ◽  
Running Speed ◽  
Single Degree Of Freedom ◽  
Single Degree ◽  
Constant Rate ◽  
Summation Of Series ◽  
Spring System ◽  
Mass Spring

A solution, in terms of known integrals, is obtained for the motion from rest of a machine, idealised as an undamped linear mass-spring system, when subjected to an exciting force whose frequency varies at a constant rate.In many installations of modern high speed machinery the running speed of the machine is in excess of the resonant or natural frequency of the system, and consequently starting up or stopping the machine could result in vibrations of large amplitude. The problem of assessing the magnitude and duration of these vibrations is very complicated and has been solved analytically only for the case of a single degree of freedom system excited by an oscillating force whose frequency varies linearly with time. However, even this solution is not easy to evaluate, the integrals involved demanding either graphical construction and numerical integration or summation of series.

scholarly journals Asymmetric and chaotic responses of dry friction oscillators with different static and kinetic coefficients of friction

Meccanica ◽  
2021 ◽  
Author(s):  
Gábor Csernák ◽  
Gábor Licskó
Keyword(s):  
Dry Friction ◽  
Continuation Method ◽  
Friction Model ◽  
Lugre Friction Model ◽  
Kinetic Coefficients ◽  
Friction Oscillator ◽  
Lugre Friction ◽  
Friction Parameters ◽  
Two Parameter ◽  
Parameter Bifurcation

AbstractThe responses of a simple harmonically excited dry friction oscillator are analysed in the case when the coefficients of static and kinetic coefficients of friction are different. One- and two-parameter bifurcation curves are determined at suitable parameters by continuation method and the largest Lyapunov exponents of the obtained solutions are estimated. It is shown that chaotic solutions can occur in broad parameter domains—even at realistic friction parameters—that are tightly enclosed by well-defined two-parameter bifurcation curves. The performed analysis also reveals that chaotic trajectories are bifurcating from special asymmetric solutions. To check the robustness of the qualitative results, characteristic bifurcation branches of two slightly modified oscillators are also determined: one with a higher harmonic in the excitation, and another one where Coulomb friction is exchanged by a corresponding LuGre friction model. The qualitative agreement of the diagrams supports the validity of the results.

Synthesis Design and Analysis of a Hybrid Controller for Robotic Arms

2016 ◽  
Author(s):  
Dan Zhang ◽  
Bin Wei
Keyword(s):  
Pid Controller ◽  
Adaptive Controller ◽  
Convergence Speed ◽  
Model Reference ◽  
Robotic Arms ◽  
Hybrid Controller ◽  
Comparison Results ◽  
Convergence Performance ◽  
Model Reference Adaptive ◽  
Better Than

In this paper, a hybrid controller for robotic arms is proposed and designed by combining a proportional-integral-derivative controller (PID) and a model reference adaptive controller (MRAC) in order to further improve the accuracy and joint convergence speed performance. The convergence performance of the PID controller, the model reference adaptive controller and the PID+MRAC hybrid controller for 1-DOF and 2-DOF manipulators are compared. The comparison results show that the convergence speed and its performance for the MRAC and the PID+MRAC controllers are better than that of the PID controller, and the convergence performance for the hybrid control is better than that of the MRAC control.

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