Delayed Reference Control Applied to Flexible Link Mechanisms: A Scheme for Effective and Stable Control

2011 ◽  
Vol 134 (1) ◽  
Author(s):  
Giovanni Boschetti ◽  
Dario Richiedei ◽  
Alberto Trevisani
Keyword(s):  
Vibration Control ◽  
Vibration Damping ◽  
Flexible Link ◽  
Damping Force ◽  
Flexible Links ◽  
Equivalent Damping ◽  
The Stability ◽  
Delayed Time ◽  
Reference Input ◽  
Stable Control

This paper extends the use of delayed reference controllers to the simultaneous motion and vibration control of flexible link mechanisms. Vibration damping is achieved by introducing an “equivalent damping force” into the system through the computation of a suitable delayed time. The delayed time, which is based on the measured vibrations, is then employed in the trajectory planner to set the reference input. The stability of the controller is discussed and its effectiveness is proved by applying it to a four-bar planar linkage with flexible links.

scholarly journals Active vibration control of a flexible link robot with the use of piezoelectric actuators

2018 ◽  
Vol 148 ◽  
pp. 11005 ◽  
Author(s):  
Darren Williams ◽  
Hamed Haddad Khodoparast ◽  
Chenyuang Yang
Keyword(s):  
Vibration Control ◽  
Research Effort ◽  
Active Vibration Control ◽  
Beam Theory ◽  
Flexible Link ◽  
Flexible Links ◽  
Robot Systems ◽  
Active Vibration ◽  
Euler Bernoulli Beam ◽  
General Method

Within robot systems the use of flexible links could solve many issues raised by their rigid counterparts. However, when these flexible links are integrated within systems which include moving parts their main issue lies in the vibrations experienced along their length due to disturbances. Much research effort has been made to solve this issue, with particular attention being paid to the application of piezoelectric patches as actuators within active vibration control (AVC). The study will consist of accurate models of a flexible link and two surface bonded piezoelectric patches, where the link and the piezoelectric patches will be modelled through the use of Euler-Bernoulli beam theory (EBT). The link will be subject to an initial displacement at its free end, and the resulting displacement of this end of the beam is to be controlled using a classic proportional-differential (PD) controller. The voltages to be applied across each of the actuators is to be controlled in accordance with the displacement of the free end of the beam, the actuators will then induce a strain upon the link opposing the movement of the tip. This research outlines this general method, obtains the best location of the piezoelectric patches and the control gains to be used, and proves that the method can be used to attenuate the vibrations experienced by a flexible link.

scholarly journals Experimental Study of Active Vibration Control of Planar 3-RRR Flexible Parallel Robots Mechanism

2016 ◽  
Vol 2016 ◽  
pp. 1-17 ◽  
Author(s):  
Qinghua Zhang ◽  
Xianmin Zhang ◽  
Junyang Wei
Keyword(s):  
Strain Rate ◽  
Vibration Control ◽  
Active Vibration Control ◽  
Elastic Vibration ◽  
Parallel Robots ◽  
Flexible Link ◽  
Flexible Links ◽  
Rate Feedback ◽  
Active Vibration ◽  
General Motion

An active vibration control experiment of planar 3-RRR flexible parallel robots is implemented in this paper. Considering the direct and inverse piezoelectric effect of PZT material, a general motion equation is established. A strain rate feedback controller is designed based on the established general motion equation. Four control schemes are designed in this experiment: three passive flexible links are controlled at the same time, only passive flexible link 1 is controlled, only passive flexible link 2 is controlled, and only passive flexible link 3 is controlled. The experimental results show that only one flexible link controlled scheme  suppresses elastic vibration and cannot suppress the elastic vibration of the other flexible links, whereas when three passive flexible links are controlled at the same time, they are able to effectively suppress the elastic vibration of all of the flexible links. In general, the experiment verifies that a strain rate feedback controller is able to effectively suppress the elastic vibration of the flexible links of plane 3-RRR flexible parallel robots.

MULTI-MODE VIBRATION CONTROL AND POSITION ERROR ANALYSIS OF PARALLEL MANIPULATOR WITH MULTIPLE FLEXIBLE LINKS

2010 ◽  
Vol 34 (2) ◽  
pp. 197-213 ◽  
Author(s):  
Xuping Zhang ◽  
James K. Mills ◽  
William L. Cleghorn
Keyword(s):  
Vibration Control ◽  
Parallel Manipulator ◽  
Position Error ◽  
Flexible Link ◽  
Flexible Links ◽  
Position Errors ◽  
Mode Vibration ◽  
Moving Platform ◽  
Multi Mode ◽  
Modal Space

This paper presents multi-mode vibration control and analysis of moving platform position errors of a planar 3-PRR parallel manipulator with three flexible intermediate links using PZT transducers. The active vibration controller is designed in modal space with modal filters and modal synthesizers determined from the flexible link vibration characteristics. Estimation of the moving platform position error is conducted using measurements of the flexible link deflection from PZT sensors mounted on the flexible intermediate links. An effective strategy for determining the control gains to reduce the vibrations of higher order modes is proposed through modification of the independent modal space control (IMSC) method. The proposed independent modal control strategy is experimentally implemented with first two modes targeted for control on a parallel manipulator with multiple flexible links. The experimental results show that the vibrations of the first two modes are effectively suppressed, and the position error of the moving platform is substantially reduced.

Vibration Control of a Cantilever Beam with Time Delay State Feedback

2006 ◽  
Vol 61 (12) ◽  
pp. 629-640 ◽  
Author(s):  
Atef F. El-Bassiouny
Keyword(s):  
Time Delay ◽  
Vibration Control ◽  
Cantilever Beam ◽  
State Feedback ◽  
Multiple Scales ◽  
State Feedback Control ◽  
Response Curves ◽  
Flow Equations ◽  
Equivalent Damping ◽  
The Stability

The primary and subharmonic resonance of order one-third of a cantilever beam under state feedback control with a time delay are investigated. Using the method of multiple scales, we obtain two slow flow equations for the amplitude and phase. The first-order approximate solution is derived and the effect of time delay on the resonance is investigated. The concept of an equivalent damping, related to the delay feedback, is proposed and an appropriate choice of the feedback gains and the time delay is discussed from the viewpoint of vibration control. The fixed points corresponding to the periodic motion of the starting system are determined, and the frequency-response and external excitation-response curves are shown. Bifurcation analysis is conducted in order to examine the stability of the system.

scholarly journals The Application of an Impedance-Passivity Controller in Haptic Stability Analysis

2021 ◽  
Vol 11 (4) ◽  
pp. 1618
Author(s):  
Ping-Nan Chen ◽  
Yung-Te Chen ◽  
Hsin Hsiu ◽  
Ruei-Jia Chen
Keyword(s):  
Control Systems ◽  
Force Feedback ◽  
Training System ◽  
Considerable Time ◽  
Virtual Training ◽  
Control Gain ◽  
Negative Damping ◽  
The Stability ◽  
Time Required ◽  
Stable Control

This paper proposes a passivity theorem on the basis of energy concepts to study the stability of force feedback in a virtual haptic system. An impedance-passivity controller (IPC) was designed from the two-port network perspective to improve the chief drawback of haptic systems, namely the considerable time required to reach stability if the equipment consumes energy slowly. The proposed IPC can be used to achieve stability through model parameter selection and to obtain control gain. In particular, haptic performance can be improved for extreme cases of high stiffness and negative damping. Furthermore, a virtual training system for one-degree-of-freedom sticking was developed to validate the experimental platform of our IPC. To ensure consistency in the experiment, we designed a specialized mechanical robot to replace human operation. Finally, compared with basic passivity control systems, our IPC could achieve stable control rapidly.

Experimental Study of Fatigue Performance of Stay Cable Damper

2014 ◽  
Vol 487 ◽  
pp. 404-407
Author(s):  
Dong Liang ◽  
Zi Shuo Li
Keyword(s):  
Experimental Study ◽  
Good Condition ◽  
Experimental Results ◽  
Test Results ◽  
Stay Cable ◽  
Damping Force ◽  
Durability Test ◽  
Equivalent Damping ◽  
Stay Cables ◽  
Performance Deterioration

Oil dampers are widely used as a popular countermeasure to mitigate the stay cables vibration. In this study, one actual oil damper designed for some long cable-stayed was experimentally investigated to evaluate the durability. 4 million cycles loading, with frequency of 4 Hz and amplitude of 1 mm, was imposed on the damper. The excitation displacement and damping force were measured and the equivalent damping was calculated from the experimental results. The stiffness effects of dampers behaved during durability tests were also analyzed quantitatively. The test results showed that the dampers were still in good condition after 4 million cycles loading and the dampers temperatures were stable at 50 degree centigrade during the test. According to the durability test results, a model for performance deterioration of damper was proposed to predict the lifetime of oil dampers.

Modification of Neuron PID Control in Case of Improper Learning Factors

2012 ◽  
Vol 433-440 ◽  
pp. 6795-6801
Author(s):  
Xue Gui Zhu ◽  
Zhi Hong Fu ◽  
Xing Zhe Hou
Keyword(s):  
Steady State ◽  
Reference Signal ◽  
Stability And Convergence ◽  
Simulation Experiments ◽  
Slow Dynamic ◽  
Penalty Factor ◽  
The Stability ◽  
Learning Factors ◽  
Control Output ◽  
Reference Input

Some modifications of conventional neuron proportional-integral-differential controller (NPID) are presented in this paper to prevent its slow dynamic response and loss of control in case of improper learning factors. The quasi-step signal replaces the step signal as the reference signal to improve the dynamic characteristics. The control output of NPID is modified every step by multiplying a penalty factor called senior teacher signal to suppress further the overshoot and compress the settling time. The steady-state error from the modified NPID (MNPID) is reduced or removed by adjusting dynamically reference input signal while excluding the pseudo steady state. Lots of simulation experiments are done to prove the stability and convergence of the MNPID control algorithm.

The Bionic Vibration Damping Technology and its Inspiration for the High Speed Milling Cutter

2012 ◽  
Vol 226-228 ◽  
pp. 98-101
Author(s):  
Hong Qing Lv ◽  
Wei Xiao Tang ◽  
Qing Hua Song ◽  
Shan Shan Sun
Keyword(s):  
Vibration Control ◽  
High Speed ◽  
Vibration Damping ◽  
Control Technology ◽  
Ambient Vibrations ◽  
Milling Cutter ◽  
High Speed Milling ◽  
Important Concept ◽  
Good Ability ◽  
Mechanical Models

A review of research on the vibration control technology inspiration from the biological vibration damping mechanisms is described. First the important concept and background of the bionic vibration damping technology are briefly introduced. Then the basic theories and its applications in the engineering fields are elaborated from three aspects: vibration damping mechanisms of the creatures own the good ability to withstand the ambient vibrations, mechanical models of biological prototypes and its application progress in the practical occasions.

Robust mixed-norm position and vibration control of flexible link mechanisms

Mechatronics ◽  
2005 ◽  
Vol 15 (7) ◽  
pp. 767-791 ◽  
Author(s):  
R. Caracciolo ◽  
D. Richiedei ◽  
A. Trevisani ◽  
V. Zanotto
Keyword(s):  
Vibration Control ◽  
Mixed Norm ◽  
Flexible Link
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