A Co-Optimization Method of Actuators/Sensors Placement and LQG Controller for Vibration Suppression

Magnetorheological dampers have been used in automotive industry and civil engineering applications for shock and vibration control for some time. While such devices are known to provide reliable shock and vibration suppression, there exist emerging applications in which the magnetorheological dampers have to be optimized in terms of power consumption and overall weight (e.g. energy-efficient electric vehicles). Utilizing traditional optimal design approaches to tackle those issues can sometimes lead to convergence problems such as getting trapped in a local extremum and failing to converge to the global optimum. Furthermore, manufacturing limitations are usually not taken into account in the optimization process which may hamper achieving an optimal design. In this article, we present a method for optimal design of magnetorheological dampers by utilizing mathematical optimization and finite element analysis. The proposed method avoids infeasible solutions by considering physical constraints such as fabrication limitations and tolerances. This approach takes every single feasible solution into account so that the final solution would be the global extremum of the optimization cost function. The proposed approach is applied to optimize a complex magnetorheological damper structure with different types of materials such as steel and AlNiCo. In particular, we present the design of a valve-mode magnetorheological damper with AlNiCo integrated as its core. A magnetorheological damper prototype is manufactured based on the proposed optimization method and tested experimentally.

Download Full-text

H 2, Mixed H2/H∞ and H2/L1 Optimally Tuned Passive Isolators and Absorbers

Journal of Dynamic Systems Measurement and Control ◽

10.1115/1.2802420 ◽

1998 ◽

Vol 120 (2) ◽

pp. 282-287 ◽

Cited By ~ 4

Author(s):

Wassim M. Haddad ◽

Ali Razavi

Keyword(s):

Frequency Response ◽

Ad Hoc ◽

Vibration Suppression ◽

Peak Frequency ◽

Optimization Method ◽

Worst Case ◽

Practical Applications ◽

System Vibration ◽

Response Performance ◽

Optimization Schemes

In many practical applications, unbalanced rotating machinery cause vibrations that transmit large oscillatory forces to the system foundation. Using ad hoc optimization schemes tuned isolators and absorbers have traditionally been designed to suppress system vibration levels by attempting to minimize the peak frequency response of the force/displacement transmissibility system transfer function. In this paper, we formulate the classical isolator and absorber vibration suppression problems in terms of modern system theoretic criteria involving H2 (shock response), mixed H2/H∞ (worst-case peak frequency response), and mixed H2/L1 (worst-case peak amplitude response) performance measures. In particular, using a quasi-Newton optimization method we design H2, mixed H2/H∞ and mixed H2/L1 optimally tuned isolators and absorbers for multi-degree-of-freedom vibrational systems. Finally, we compare our results to the classical Snowdon and Den Hartog absorbers.

Download Full-text

Active Vibration Control of Resonant Systems via Multivariable Modified Positive Position Feedback

Volume 3: Nonlinear Estimation and Control; Optimization and Optimal Control; Piezoelectric Actuation and Nanoscale Control; Robotics and Manipulators; Sensing; System Identification (Estimation for Automotive Applications, Modeling, Therapeutic Control in Bio-Systems); Variable Structure/Sliding-Mode Control; Vehicles and Human Robotics; Vehicle Dynamics and Control; Vehicle Path Planning and Collision Avoidance; Vibrational and Mechanical Systems; Wind Energy Systems and Control ◽

10.1115/dscc2013-3910 ◽

2013 ◽

Cited By ~ 7

Author(s):

Ehsan Omidi ◽

S. Nima Mahmoodi

Keyword(s):

Vibration Control ◽

Vibration Suppression ◽

Active Vibration Control ◽

Optimization Method ◽

Resonant Structures ◽

Distributed Structure ◽

Positive Position Feedback ◽

Lqr Problem ◽

Position Feedback ◽

Resonant Systems

One of the predominant difficulties in the theory of distributed structure control systems comes from the fact that these resonant structures have a large number of active modes in the working band-width. Among the different methods for vibration control, Positive Position Feedback (PPF) is of interest, which uses piezoelectric actuation to overcome the vibration as a collocated controller. Modified Positive Position Feedback (MPPF) is later presented by adding a first-order damping compensator to the conventional second-order compensator, to have a better performance for steady-state and transient disturbances. In this paper, Multivariable Modified Positive Position Feedback (MMPPF) is presented to suppress the unwanted resonant vibrations in the structure. This approach benefits the advantages of MPPF, while it controls larger number vibration modes. An optimization method is introduced, consisting of a cost function that is minimized in the area of the stability of the system. LQR problem is also used to optimize the controller performance by optimized gain selection. It is shown that the LQR-optimized MMPPF controller provides vibration suppression in more efficiently manner.

Download Full-text

Mixed H2/H∞ guaranteed cost control for high speed elevator active guide shoe with parametric uncertainties

Mechanics & Industry ◽

10.1051/meca/2020044 ◽

2020 ◽

Vol 21 (5) ◽

pp. 502

Author(s):

Chen Chen ◽

Ruijun Zhang ◽

Qing Zhang ◽

Lixin Liu

Keyword(s):

Control Strategy ◽

High Speed ◽

State Feedback ◽

Vibration Suppression ◽

Ride Comfort ◽

Optimization Method ◽

State Feedback Control ◽

Guide Rail ◽

Vibration Displacement ◽

Guaranteed Cost

Aiming at the phenomenon that the elevator car system generates horizontal vibration due to the unevenness of the guide rail and the guide shoe modeling uncertainty caused by friction, wear and spring aging between the rolling guide shoe and the guide rail, a mixed H2/H∞ optimal guaranteed cost state feedback control strategy is proposed. Firstly, as the high-speed elevator car system always exist the phenomenon of stiffness and damping uncertainty in the guide shoe, the LFT method is adopted to construct the state space equation of the car system with parameter uncertainty. Secondly, considering the performance indexes of horizontal acceleration at the center of the car floor and the guide shoe vibration displacement system, an optimal guaranteed performance state feedback controller is designed based on the linear convex optimization method, which to minimize H2 performance index and achieve the specified H∞ performance level. Thirdly, the free matrix is introduced to reduce the conservatism of the controller. Finally, by comparing the simulation results with other control methods under the same conditions, it is verified that the control strategy can make the car system have better vibration suppression ability, and can significantly improve the ride comfort of the elevator.

Download Full-text

A Vibration Suppression Method for the Multistage Rotor of an Aero-Engine Based on Assembly Optimization

Machines ◽

10.3390/machines9090189 ◽

2021 ◽

Vol 9 (9) ◽

pp. 189

Author(s):

Yue Chen ◽

Jiwen Cui ◽

Xun Sun

Keyword(s):

Vibration Suppression ◽

Optimization Methods ◽

Optimization Method ◽

Rotor System ◽

Vibration Velocity ◽

Transfer Model ◽

Dynamics Model ◽

Aero Engine ◽

Vibration Responses ◽

Optimal Assembly

The assembly quality of the multistage rotor is an essential factor affecting its vibration level. The existing optimization methods for the assembly angles of the rotors at each stage can ensure the concentricity and unbalance meet the requirements, but it cannot directly ensure its vibration responses meet the indexes. Therefore, in this study, we first derived the excitation formulas of the geometric and mass eccentricities on the multistage rotor and introduced it into the dynamics model of the multistage rotor system. Then, the coordinate transfer model of the geometric and mass eccentricities errors, including assembly angles of the rotors at all stages, was established. Moreover, the mathematical relationship between the assembly angles of the rotors at all stages and the nodal vibration responses was established by combining the error transfer model with the dynamics model of the multistage rotor system. Furthermore, an optimization function was developed, which takes the assembly angles as the optimization variables and the maximum vibration velocity at the bearings as the optimization objective. Finally, a simplified four-stage high-pressure rotor system was assembled according to the optimal assembly angles calculated in the simulations. The experimental results showed that the maximum vibration velocity at the bearings under the optimal assembly was reduced by 69.6% and 45.5% compared with that under the worst assembly and default assembly. The assembly optimization method proposed in this study has a significant effect on the vibration suppression of the multistage rotor of an aero-engine.

Download Full-text

Trajectory Optimization Method of Special Operation Redundant Robot for Vibration Suppression

Journal of Mechanical Engineering ◽

10.3901/jme.2012.01.013 ◽

2012 ◽

Vol 48 (01) ◽

pp. 13 ◽

Cited By ~ 3

Author(s):

Junyi SHAO

Keyword(s):

Trajectory Optimization ◽

Vibration Suppression ◽

Optimization Method ◽

Redundant Robot

Download Full-text

Locations optimization of multiple cable-drivers for an anti-wind disturbance system in large antenna

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1177/0954406220936730 ◽

2020 ◽

pp. 095440622093673

Author(s):

Wei Liang ◽

Jin Huang ◽

Jie Zhang

Keyword(s):

Optimization Algorithm ◽

Vibration Suppression ◽

Optimization Method ◽

Structural Vibration ◽

Joint Optimization ◽

Wind Disturbance ◽

Antenna Structure ◽

Feasible Domain ◽

Geometric Relationship ◽

Single Slide

Since the structural vibration deformation of a large antenna under wind disturbance leads to the pointing deterioration, an adaptive anti-wind disturbance system was presented by Liang et al. (Int. J. Antennas Propag., Article ID 2015341, 2019). To further improve the vibration suppression performance, this paper presents a locations-optimization algorithm of multiple cable-drivers for the anti-wind disturbance system. First, according to the spatial geometric relationship among the antenna structure, single slide track, four cables and drivers, the feasible domain of the drivers is determined. Next, the separate optimization method, and the joint optimization method for the locations of the four drivers are proposed, respectively. Finally, the simulation implementation of a 7.3 m antenna under various wind conditions is used to compare the joint optimization method and the separate optimization method.

Download Full-text

Optimal Level Set Vibration Control of Plate Structures

Volume 1: 23rd Biennial Conference on Mechanical Vibration and Noise, Parts A and B ◽

10.1115/detc2011-48050 ◽

2011 ◽

Author(s):

Masoud Ansari ◽

Amir Khajepour ◽

Ebrahim Esmailzadeh

Keyword(s):

Topology Optimization ◽

Level Set ◽

Vibration Suppression ◽

Optimization Method ◽

Optimal Level ◽

Optimum Shape ◽

Optimization Approach ◽

Constrained Layer Damping ◽

Fundamental Vibration ◽

Flexural Vibrations

This research is motivated by the need for control of flexural vibrations of lightweight plates. It addresses application of the level set method in optimal control of vibrations in plate-like structures. One of the most commonly practiced methods in control of vibration is to apply constrained layer damping patches to the surface of a structure. In order to consider the weight efficiency of the structure, the best shape and locations of the patches should be determined to achieve the optimum vibration suppression with lowest amount of damping patch. A novel topology optimization approach is proposed that is capable of finding the optimum shape and locations of the patches simultaneously. A 2D cantilever plate, undergoing flexural vibrations, will be considered. The optimal damping set will be found in the structure, such that the lowest modal energy in the fundamental vibration mode of the system is achieved. The proposed level set topology optimization method shows capability of determining the optimum damping set in structures accurately.

Download Full-text