SEMI-ACTIVE CONTROL FOR VIBRATION SUPPRESSION IN A SYSTEM SUBJECTED TO UNKNOWN DISTURBANCES

1994 ◽  
Vol 04 (04) ◽  
pp. 379-393
Author(s):  
G. LEITMANN
Keyword(s):  
Vibration Suppression ◽  
Electrorheological Fluid ◽  
Electrorheological Fluids ◽  
Joint Control ◽  
Damping Characteristics ◽  
Control Schemes ◽  
Unknown Disturbances ◽  
Simulation Results ◽  
Stiffness And Damping ◽  
External Stimuli

With the advent of materials, such as electrorheological fluids, whose material properties can be altered rapidly by means of external stimuli, employing such materials as actuators for the controlled attenuation of undesirable vibrations is now possible. Such control schemes are dubbed semi-active in that they attenuate vibrations whether applied actively or passively. We investigate various such control schemes, allowing for both separate and joint control of the stiffness and damping characteristics of the material. Simulation results are given for the case of an electrorheological fluid.

Performance analysis of a new hydropneumatic inerter-based suspension system with semi-active control effect

2020 ◽  
Vol 234 (7) ◽  
pp. 1883-1896
Author(s):  
Lin Yang ◽  
Ruochen Wang ◽  
Xiangpeng Meng ◽  
Zeyu Sun ◽  
Wei Liu ◽  
...  
Keyword(s):  
Active Control ◽  
Network Theory ◽  
Suspension System ◽  
Bench Test ◽  
Control Effect ◽  
Damping Characteristics ◽  
Control Comparison ◽  
Simulation Results ◽  
Stiffness And Damping ◽  
The Relationship

This paper develops a hydropneumatic inerter-based suspension system theoretical model to analyze its performance, based on the mechanical network theory of inerter and semi-active control. Comparison of the stiffness and damping characteristics among a passive hydropneumatic suspension system, semi-active hydropneumatic suspension system based on skyhook control, and hydropneumatic inerter-based suspension system is conducted. Moreover, the relationship between the internal coefficient of the inerter and the damping coefficient of the hydropneumatic suspension is investigated. The simulation results of the flow–volume curves of the hydropneumatic inerter-based suspension system are close to those of the semi-active hydropneumatic suspension system based on skyhook control. Furthermore, the performance of a quarter vehicle model with the hydropneumatic inerter-based suspension system is analyzed and compared to that with the semi-active hydropneumatic suspension system based on skyhook control. The simulation results show that the performance of the hydropneumatic inerter-based suspension system is as good as that of the semi-active hydropneumatic suspension system based on skyhook control, which means that the hydropneumatic inerter-based suspension system can achieve similar performance for semi-active control suspension. Finally, a prototype is developed, and a comparative bench test is carried out to verify the accuracy of the simulations. In addition, the hydropneumatic inerter-based suspension system can achieve semi-active control performance without additional hardware or energy loss.

scholarly journals Research on Damping Characteristics of Interconnected Hydropneumatic Suspension considering the Effects of Hose and Check Valve

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Hongmin Zhang ◽  
Xin Fang
Keyword(s):  
Numerical Simulation ◽  
Energy Method ◽  
Damping Ratio ◽  
Check Valve ◽  
Nonlinear Stiffness ◽  
Calculation Formula ◽  
Damping Force ◽  
Damping Characteristics ◽  
Simulation Results ◽  
Stiffness And Damping

The interconnected hydropneumatic suspension (ICHPS) has not only the nonlinear stiffness and damping of the independent hydropneumatic suspension (IDHPS) but also antiroll and antipitch functions. The existing analysis of hydropneumatic suspension damping mainly focuses on the orifice and check valve in the suspension cylinder. In this study, the calculation formula of the damping force of ICHPS is established, and the numerical simulation results show that the damping characteristics of the hydraulic hose cannot be ignored. The influence of check valve and hose on the damping characteristics is analyzed. Through the equivalent energy method, the equivalent compression damping ratio and the equivalent recovery damping ratio of the ICHPS are established. It is pointed out that when designing the damping characteristics of the ICHPS, it is necessary to select the orifices, check valves, and hose damping reasonably to make the damping characteristics get the best match.

scholarly journals Dynamic Behavior of Sandwich Structures with Magnetorheological Elastomer: A Review

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7025
Author(s):  
Umer Sharif ◽  
Beibei Sun ◽  
Shahid Hussain ◽  
Dauda Sh. Ibrahim ◽  
Orelaja Oluseyi Adewale ◽  
...  
Keyword(s):  
Vibration Control ◽  
Smart Materials ◽  
Vibration Suppression ◽  
Sandwich Structures ◽  
Core Layer ◽  
Geometrical Structures ◽  
Damping Characteristics ◽  
Field Dependent ◽  
Physical Features ◽  
Stiffness And Damping

Magnetorheological (MR) materials are classified as smart materials that can alter their rheological features once exposed to peripheral magnetic fields. MR materials have been a standard and one of the primary smart materials for the last few decades due to their outstanding vibration control performance in adaptive sandwich structures and systems. This paper reviews the vibration suppression investigations of flexible constructions using MR elastomers (MREs). In relations of field-dependent controllability, physical features such as stiffness and the damping of different geometrical structures integrated with the core layer of MREs are explored. The veracity of the knowledge is discussed in this article, whereby sandwich structures with different MR treatment configurations are analyzed for free and forced vibration, MRE sandwich structures are analyzed for stability under different working conditions, and the optimal positions of fully and partially treated MRE sandwich structures for improved vibration control are identified. MR materials′ field-dependent stiffness and damping characteristics are also discussed in this article. A few of the most noteworthy research articles over the last several years have been summarized.

Semiactive vibration suppression with electrorheological-fluid dampers

AIAA Journal ◽  
1997 ◽  
Vol 35 ◽  
pp. 1844-1852
Author(s):  
Junjiro Onoda ◽  
Kenji Minesugi ◽  
Hyun-Ung Oh
Keyword(s):  
Vibration Suppression ◽  
Electrorheological Fluid ◽  
Fluid Dampers

Improved electrorheological-fluid variable damper designed for semiactive vibration suppression

AIAA Journal ◽  
2000 ◽  
Vol 38 ◽  
pp. 1736-1741
Author(s):  
Junjiro Onoda ◽  
Hyun-Ung Oh ◽  
Kenji Minesugi
Keyword(s):  
Vibration Suppression ◽  
Electrorheological Fluid

A computationally efficient adaptive robust control scheme for a quad-rotor transporting cable-suspended payloads

2021 ◽  
pp. 095441002110136
Author(s):  
Nasim Ullah ◽  
Irfan Sami ◽  
Wang Shaoping ◽  
Hamid Mukhtar ◽  
Xingjian Wang ◽  
...  
Keyword(s):  
Robust Control ◽  
Fractional Order ◽  
Sliding Mode ◽  
Adaptive Robust Control ◽  
Computationally Efficient ◽  
Control Scheme ◽  
Control Schemes ◽  
Adaptive Laws ◽  
Unknown Disturbances ◽  
The Stability

This article proposes a computationally efficient adaptive robust control scheme for a quad-rotor with cable-suspended payloads. Motion of payload introduces unknown disturbances that affect the performance of the quad-rotor controlled with conventional schemes, thus novel adaptive robust controllers with both integer- and fractional-order dynamics are proposed for the trajectory tracking of quad-rotor with cable-suspended payload. The disturbances acting on quad-rotor due to the payload motion are estimated by utilizing adaptive laws derived from integer- and fractional-order Lyapunov functions. The stability of the proposed control systems is guaranteed using integer- and fractional-order Lyapunov theorems. Overall, three variants of the control schemes, namely adaptive fractional-order sliding mode (AFSMC), adaptive sliding mode (ASMC), and classical Sliding mode controllers (SMC)s) are tested using processor in the loop experiments, and based on the two performance indicators, namely robustness and computational resource utilization, the best control scheme is evaluated. From the results presented, it is verified that ASMC scheme exhibits comparable robustness as of SMC and AFSMC, while it utilizes less sources as compared to AFSMC.

A Design Method of LS-SVM Based Stable Adaptive Controller for a Class of Nonlinear Systems

2011 ◽  
Vol 48-49 ◽  
pp. 17-20
Author(s):  
Chun Li Xie ◽  
Tao Zhang ◽  
Dan Dan Zhao ◽  
Cheng Shao
Keyword(s):  
Nonlinear Systems ◽  
Design Method ◽  
Nonlinear Function ◽  
Lyapunov Stability Theory ◽  
Adaptive Controller ◽  
Control Law ◽  
Continuous Systems ◽  
Control Schemes ◽  
Closed Systems ◽  
Simulation Results

A design method of LS-SVM based stable adaptive controller is proposed for a class of nonlinear continuous systems with unknown nonlinear function in this paper. Due to the fact that the control law is derived based on the Lyapunov stability theory, the scheme can not only solve the tracking problem of this class of nonlinear systems, but also it can guarantee the asymptotic stability of the closed systems, which is superior to many LS-SVM based control schemes. The effectiveness of the proposed scheme is demonstrated by simulation results.

Rotordynamic Performance of a Rotor Supported on Bump Type Foil Gas Bearings: Experiments and Predictions

2006 ◽  
Vol 129 (3) ◽  
pp. 850-857 ◽  
Author(s):  
Luis San Andrés ◽  
Dario Rubio ◽  
Tae Ho Kim
Keyword(s):  
High Speed ◽  
Critical Speed ◽  
Load Capacity ◽  
Test System ◽  
Foil Bearings ◽  
Rotor Imbalance ◽  
Synchronous Motion ◽  
Damping Characteristics ◽  
Rotor Surface ◽  
Stiffness And Damping

Gas foil bearings (GFBs) satisfy the requirements for oil-free turbomachinery, i.e., simple construction and ensuring low drag friction and reliable high speed operation. However, GFBs have a limited load capacity and minimal damping, as well as frequency and amplitude dependent stiffness and damping characteristics. This paper provides experimental results of the rotordynamic performance of a small rotor supported on two bump-type GFBs of length and diameter equal to 38.10mm. Coast down rotor responses from 25krpm to rest are recorded for various imbalance conditions and increasing air feed pressures. The peak amplitudes of rotor synchronous motion at the system critical speed are not proportional to the imbalance introduced. Furthermore, for the largest imbalance, the test system shows subsynchronous motions from 20.5krpm to 15krpm with a whirl frequency at ∼50% of shaft speed. Rotor imbalance exacerbates the severity of subsynchronous motions, thus denoting a forced nonlinearity in the GFBs. The rotor dynamic analysis with calculated GFB force coefficients predicts a critical speed at 8.5krpm, as in the experiments; and importantly enough, unstable operation in the same speed range as the test results for the largest imbalance. Predicted imbalance responses do not agree with the rotor measurements while crossing the critical speed, except for the lowest imbalance case. Gas pressurization through the bearings’ side ameliorates rotor subsynchronous motions and reduces the peak amplitudes at the critical speed. Posttest inspection reveal wear spots on the top foils and rotor surface.

Nonlinear Isolator Optimization Using RMS Cost Function

2004 ◽  
Author(s):  
A. Narimani ◽  
M. F. Golnaraghi
Keyword(s):  
Closed Form Solution ◽  
Optimization Method ◽  
Relative Displacement ◽  
Form Solution ◽  
Jump Phenomenon ◽  
Nonlinear Parameters ◽  
Strongly Nonlinear ◽  
Damping Characteristics ◽  
Stiffness And Damping ◽  
Boundary Limits

In this paper using a modified averaging method the frequency response of a general nonlinear isolator is obtained. Stiffness and damping characteristics are considered cubic functions of displacement and velocity through the isolator. Analytical results are compared with those obtained by numerical integration in order to validate the closed form solution for strongly nonlinear isolator. While increasing the nonlinearity in the system improves the response of the isolator, stability and jump avoidance conditions set boundary limits for the parameters. The effects of nonlinear parameters to avoid jump phenomenon are discussed in detail. The set of parameters where the system behaves regularly are found and the nonlinear isolator is optimized based on RMS optimization method. Using this method the RMS function of absolute acceleration of the sprung mass is minimized versus the RMS function of relative displacement.

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