scholarly journals Design of an active compliant liquid column damper by LQR and wavelet linear quadratic regulator control strategies

2018 ◽  
Vol 25 (12) ◽  
pp. e2265 ◽  
Author(s):  
Soumi Bhattacharyya ◽  
Aparna Dey Ghosh ◽  
Biswajit Basu
2021 ◽  
Vol 29 (1) ◽  
Author(s):  
Oscar Andrew Zongo ◽  
Anant Oonsivilai

This paper presents a comparison between a proportional-integral controller, low pass filters, and the linear quadratic regulator in dealing with the task of eliminating harmonic currents in the grid-connected photovoltaic system. A brief review of the existing methods applied to mitigate harmonic currents is presented. The Perturb & Observe technique was employed for maximum power point tracking. The PI control, low pass filters, and the linear quadratic regulator are discussed in detail in terms of their control strategies. The grid current was analyzed in the system with all three of the controllers applied to control the voltage source inverter of the solar photovoltaic system connected to the grid through an L filter and LCL filter and simulated in MATLAB/SIMULINK. The simulation results obtained have proven the robustness of the linear quadratic regulator over other methods. The technique lowers the grid current total harmonic distortion from 7.85% to 2.13%.


2014 ◽  
Vol 663 ◽  
pp. 146-151 ◽  
Author(s):  
Noraishikin Zulkarnain ◽  
Hairi Zamzuri ◽  
Saiful Amri Mazlan

The objective of this paper is to design a linear quadratic regulator (LQR) and linear quadratic Gaussian (LQG) controllers for an active anti-roll bar system. The use of an active anti-roll bar will be analysed from two different perspectives in vehicle ride comfort and handling performances. This paper proposed the basic vehicle dynamic modelling with four degree of freedom (DOF) on half car model and are described that show, why and how it is possible to control the handling and ride comfort of the car, with the external forces also control strategies on the front anti-roll bar. By simulation analysis, the design model is validity and the performance under control of linear quadratic regulator (LQR) and linear quadratic Gaussian (LQG) controller are achieved. Both two controllers are modeled in MATLAB/SIMULINK environment. It has to be determined which control strategy delivers better performance with respect to roll angle and the roll rate of half vehicle body. The result shows, however, that LQG produced better response compared to a LQR strategy.


Author(s):  
Huyao Wu ◽  
Bin Ran

Abstract In this paper, the control strategies for Path Following System (PFS) in autonomous vehicle, which lets vehicle stay in the center of its lane is discussed, we will create a plant mechanical, mathematical and error dynamics model for the study of PFS, which is stabilized by the state-feedback control law, also considers the output where the sensor is made. We apply mainly an optimal control or configure a Linear-quadratic Regulator (LQR) for state space systems and compare it to that based on the Pole Assignment (PA). Combined with a typical operating scenario of the road, we mainly consider static and dynamic errors in the moving process, and how intensely the error fluctuates and how errors are related to the next time. Figures and data show that the LQR controller successfully adjusts and gives appropriate input to let the vehicle approach to centerline, errors and the steering angle required to negotiate a curved road are presented and analyzed, finally relevant conclusions are drawn.


Author(s):  
Krishna Rangavajhula ◽  
H.-S. Jacob Tsao

A key source of safety and infrastructure issues for operations of longer combination vehicles (LCVs) is off-tracking, which has been used to refer to the general phenomenon that the rear wheels of a truck do not follow the track of the front wheels and wander off the travel lane. In this paper, we examine the effectiveness of command-steering in reducing off-tracking during a 90-degree turn at low and high speeds in an articulated system with a tractor and three full trailers. In command steering, rear front axles of the trailers are steered proportionately to the articulation angle between the tractor and trailing units. We then consider several control strategies to minimize off-tracking and rearward amplification of this system. A minimum rearward amplification ratio (RWA), as a surrogate for minimum off tracking, has been used as the control criterion for medium to high speeds to arrive at an optimal Linear Quadratic Regulator (LQR) controller. As for low speeds, the maximum radial offset between the tractor and trailer 3 is minimized in the design of the controller. Robustness of the optimal controller with respect to tyre-parameter perturbations is then examined. Based on the simulation results, we find that, active command steering is very effective in reducing off tracking at low- as well as high-speed 90-degree turns. To achieve acceptable levels of RWA and off tracking, at least two of the three trailers must be actively command-steered. Among the three two-trailer-steering possibilities, actively steering trailers 1 and 2 is most cost-effective and results in the lowest RWA for medium- to high- speeds (at which RWA is important), and off-tracking is practically eliminated for all speed regimes considered.


2010 ◽  
Vol 10 (03) ◽  
pp. 501-527 ◽  
Author(s):  
ARASH MOHTAT ◽  
AGHIL YOUSEFI-KOMA ◽  
EHSAN DEHGHAN-NIRI

This paper demonstrates the trade-off between nominal performance and robustness in intelligent and conventional structural vibration control schemes; and, proposes a systematic treatment of stability robustness and performance robustness against uncertainty due to structural damage. The adopted control strategies include an intelligent genetic fuzzy logic controller (GFLC) and reduced-order observer-based (ROOB) controllers based on pole-placement and linear quadratic regulator (LQR) conventional schemes. These control strategies are applied to a seismically excited truss bridge structure through an active tuned mass damper (ATMD). Response of the bridge-ATMD control system to earthquake excitation records under nominal and uncertain conditions is analyzed via simulation tests. Based on these results, advantages of exploiting heuristic intelligence in seismic vibration control, as well as some complexities arising in realistic conventional control are highlighted. It has been shown that the coupled effect of spill-over (due to reduction and observation) and mismatch between the mathematical model and the actual plant (due to uncertainty and modeling errors) can destabilize the conventional closed-loop system even if each is alone tolerated. Accordingly, the GFLC proves itself to be the dominant design in terms of the compromise between performance and robustness.


2008 ◽  
Vol 130 (6) ◽  
Author(s):  
Z. Q. Gu ◽  
S. O. Oyadiji

In recent years, considerable attention has been paid to the development of theories and applications associated with structural vibration control. Integrating the nonlinear mapping ability with the dynamic evolution capability, diagonal recurrent neural network (DRNN) meets the needs of the demanding control requirements in increasingly complex dynamic systems because of its simple and recurrent architecture. This paper presents numerical studies of multiple degree-of-freedom (MDOF) structural vibration control based on the approach of the backpropagation algorithm to the DRNN control method. The controller’s stability and convergence and comparisons of the DRNN method with conventional control strategies are also examined. The numerical simulations show that the structural vibration responses of linear and nonlinear MDOF structures are reduced by between 78% and 86%, and between 52% and 80%, respectively, when they are subjected to El Centro, Kobe, Hachinohe, and Northridge earthquake processes. The numerical simulation shows that the DRNN method outperforms conventional control strategies, which include linear quadratic regulator (LQR), linear quadratic Gaussian (LQG) (based on the acceleration feedback), and pole placement by between 20% and 30% in the case of linear MDOF structures. For nonlinear MDOF structures, in which the conventional controllers are ineffective, the DRNN controller is still effective. However, the level of reduction of the structural vibration response of nonlinear MDOF structures achievable is reduced by about 20% in comparison to the reductions achievable with linear MDOF structures.


2010 ◽  
Vol 163-167 ◽  
pp. 3461-3464
Author(s):  
Chuan Fu

This paper examines the effectiveness of the Active Tuned Liquid Column Gas Damper (ATLCGD) when equipped on the plan-asymmetric structures subjected to earthquake excitation. The active behaviour is obtained by adjusting the pressure at the end of the liquid column using a pressurised reservoir. The classical linear quadratic regulator (LQR) control strategy is applied to determine optimal control force of the ATLCGDs. A case study of a four-storey asymmetric structure is conducted to illustate excellent control efficacy of the proposed active TLCGD control system.


2019 ◽  
Vol 16 (2) ◽  
pp. 71-81
Author(s):  
David Javier Muñoz-Aldana ◽  
Carlos Alberto Gaviria-López

This article presents a virtual environment based on co-simulation between MatLab and MSC Adams, allowing simulation, analysis, development and validation of control strategies for tracking of position trajectories of a Remotely Operated Vehicle (ROV). The simulation results in the horizontal plane show that it is possible, in an uncomplicated way, to construct a virtual environment, which allows observing realistic movements when the forces exerted on an ROV are provided. Taking advantage of the properties of co-simulation, the experiences in this work show that this simulation strategy is very suitable for analysis purposes and control design, allowing researchers and professionals the wide use of control tools available in MATLAB for this end. In this work, a robust linear quadratic regulator (LQR) with integral action has been used to evaluate the performance of the proposed virtual environment for tracking of position trajectories. To validation purposes, widely used trajectories in naval study designs were employed such as the Zig -Zag shaped and the Circular shaped trajectories. Simulation results show that the integration of both, MatLab and MSC Adams, effectively addressees the problem of evaluation of performance of control strategies in the virtual environment. The presented approach allows gaining experience about the challenges of this kind of control problems, before dealing with the complex aspects of tuning in real experimental environments, avoiding losses and cost overruns for underwater robotics projects.


1996 ◽  
Vol 118 (3) ◽  
pp. 489-498 ◽  
Author(s):  
L. Palkovics ◽  
M. El-Gindy

Heavy vehicles play an economically important role in the transportation process, and their numbers have been increasing for several decades. The active safety of the highway system is an important consideration in the design of a heavy vehicle combination. In this paper, the handling characteristics of a 5-axle tractor-semitrailer is examined and used to test for the desired features of the vehicle’s handling and stability. Using these results the optimal control criterion is derived for the vehicle. Four different control strategies are examined by using the Linear Quadratic Regulator (LQR) approach. These are, active steering of the rear wheels of the tractor; active steering of the wheels of the trailer; active torque control in the fifth-wheel joint; and active yaw torque acting on the tractor. These controllers are designed and examined using a simplified linear vehicle model. In addition to discussing the above-mentioned approaches, this paper discusses a method of modifying the slip angles at the tractor’s rear (driven) axles, however the yaw torque at the tractor cg also can be controlled using what is called “unilateral braking.” As well, the replacement of the active torque control at the fifth wheel joint, by a control strategy based on the usage of controllable dampers at the fifth-wheel joint, will also be examined. In this case, a nonlinear mathematical model of the vehicle is used and a modified control strategy called the RLQR/H∞ approach is used to ensure the vehicle’s performance in the presence of parametric uncertainties. The examination of these control strategies is conducted by using a sophisticated non-linear vehicle model, and the influence of these control strategies on the vehicle’s directional and roll stability during severe path-follow lane-change manoeuvre is discussed.


2020 ◽  
Vol 26 (9-10) ◽  
pp. 671-679 ◽  
Author(s):  
Qunsheng Wang ◽  
Jing Zeng ◽  
Yi Wu ◽  
Bin Zhu

Considering the coupling vibration of a flexible carbody and the underneath suspended equipment, a vertical coupled vibration model of a high-speed train was constructed. A roller test rig was conducted to validate the theoretical model. To reduce carbody elastic vibration, the semi-active vibration reduction models based on the Sky-hook and the linear quadratic regulator control strategies were proposed. The semi-active suspension system was installed between the carbody and the suspended equipment, and the influence of the semi-active suspension on carbody vibration reduction was analyzed. The results show that the semi-active suspension can significantly reduce carbody vibration, especially at high operating speeds. The higher the elastic vibration of carbody, the better the vibration reduction effect of the semi-active suspension. Compared with the passive suspension and the semi-active suspension, the semi-active suspension of the Sky-hook control has a relatively wider vibration control range, and has an obvious effect on carbody rigid and elastic vibration reduction. Although the semi-active suspension of the linear quadratic regulator control had little influence on the rigid carbody vibration, it could reduce most of the elastic carbody vibration.


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