scholarly journals A Practical Control Strategy for the Maglev Self-Excited Resonance Suppression

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Jinhui Li ◽  
Dong Fang ◽  
Ding Zhang ◽  
Ying Cai ◽  
Qi Ni ◽  
...  
Keyword(s):  
Control Strategy ◽  
Ride Comfort ◽  
Block Diagram ◽  
Current Feedback ◽  
Positive Effects ◽  
Maglev Vehicle ◽  
Interaction System ◽  
Electrical Damping ◽  
The Stability ◽  
Additional Feedback

This paper addresses the control strategy for the suppression of maglev vehicle-bridge interaction resonance, which worsens the ride comfort of vehicle and degrades the safety of the bridge. Firstly, a minimum model containing a flexible bridge and ten levitation units is presented. Based on the minimum model, we pointed out that magnetic flux feedback instead of the traditional current feedback is capable of simplifying the block diagram of the interaction system. Furthermore, considering the uncertainty of the bridge’s modal frequency, the stability of the interaction system is explored according to an improved root-locus technique. Motivated by the positive effects of the mechanical damping of bridges and the feedback channels’ difference between the levitation subsystem and the bridge subsystem, the increment of electrical damping by the additional feedback of vertical velocity of bridge is proposed and several related implementation issues are addressed. Finally, the numerical and experimental results illustrating the stability improvement are provided.

scholarly journals The Modeling and Analysis for the Self-Excited Vibration of the Maglev Vehicle-Bridge Interaction System

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Jinhui Li ◽  
Jie Li ◽  
Danfeng Zhou ◽  
Lianchun Wang
Keyword(s):  
Ride Comfort ◽  
Interaction Model ◽  
Control Unit ◽  
The Self ◽  
Modeling And Analysis ◽  
Maglev Vehicle ◽  
Interaction System ◽  
Excited Vibration ◽  
Vibration Problems ◽  
The Stability

This paper addresses the self-excited vibration problems of maglev vehicle-bridge interaction system which greatly degrades the stability of the levitation control, decreases the ride comfort, and restricts the cost of the whole system. Firstly, two levitation models with different complexity are developed, and the comparison of the energy curves associated with the two models is carried out. We conclude that the interaction model with a single levitation control unit is sufficient for the study of the self-excited vibration. Then, the principle underlying the self-excited vibration is explored from the standpoint of work acting on the bridge done by the levitation system. Furthermore, the influences of the parameters, including the modal frequency and modal damping of bridge, the gain of the controller, the sprung mass, and the unsprung mass, on the stability of the interaction system are carried out. The study provides a theoretical guidance for solving the self-excited vibration problems of the vehicle-bridge interaction systems.

Towards a new design with generic modeling and adaptive control of a transformable quadrotor

2021 ◽  
pp. 1-31
Author(s):  
S.H. Derrouaoui ◽  
Y. Bouzid ◽  
M. Guiatni
Keyword(s):  
Adaptive Control ◽  
Control Strategy ◽  
Experimental Tests ◽  
Generic Model ◽  
System Control ◽  
System A ◽  
Viable Solution ◽  
Generic Modeling ◽  
Adaptive Control Strategy ◽  
The Stability

Abstract Recently, transformable Unmanned Aerial Vehicles (UAVs) have become a subject of great interest in the field of flying systems, due to their maneuverability, agility and morphological capacities. They can be used for specific missions and in more congested spaces. Moreover, this novel class of UAVs is considered as a viable solution for providing flying robots with specific and versatile functionalities. In this paper, we propose (i) a new design of a transformable quadrotor with (ii) generic modeling and (iii) adaptive control strategy. The proposed UAV is able to change its flight configuration by rotating its four arms independently around a central body, thanks to its adaptive geometry. To simplify and lighten the prototype, a simple mechanism with a light mechanical structure is proposed. Since the Center of Gravity (CoG) of the UAV moves according to the desired morphology of the system, a variation of the inertia and the allocation matrix occurs instantly. These dynamics parameters play an important role in the system control and its stability, representing a key difference compared with the classic quadrotor. Thus, a new generic model is developed, taking into account all these variations together with aerodynamic effects. To validate this model and ensure the stability of the designed UAV, an adaptive backstepping control strategy based on the change in the flight configuration is applied. MATLAB simulations are provided to evaluate and illustrate the performance and efficiency of the proposed controller. Finally, some experimental tests are presented.

scholarly journals A Unified Control Strategy of Distributed Generation for Grid-Connected and Islanded Operation Conditions Using an Artificial Neural Network

2021 ◽  
Vol 13 (11) ◽  
pp. 6388
Author(s):  
Karim M. El-Sharawy ◽  
Hatem Y. Diab ◽  
Mahmoud O. Abdelsalam ◽  
Mostafa I. Marei
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Control System ◽  
Distributed Generation ◽  
Control Strategy ◽  
Current Control ◽  
Operating Conditions ◽  
Pi Controllers ◽  
Artificial Neural ◽  
The Stability

This article presents a control strategy that enables both islanded and grid-tied operations of a three-phase inverter in distributed generation. This distributed generation (DG) is based on a dramatically evolved direct current (DC) source. A unified control strategy is introduced to operate the interface in either the isolated or grid-connected modes. The proposed control system is based on the instantaneous tracking of the active power flow in order to achieve current control in the grid-connected mode and retain the stability of the frequency using phase-locked loop (PLL) circuits at the point of common coupling (PCC), in addition to managing the reactive power supplied to the grid. On the other side, the proposed control system is also based on the instantaneous tracking of the voltage to achieve the voltage control in the standalone mode and retain the stability of the frequency by using another circuit including a special equation (wt = 2πft, f = 50 Hz). This utilization provides the ability to obtain voltage stability across the critical load. One benefit of the proposed control strategy is that the design of the controller remains unconverted for other operating conditions. The simulation results are added to evaluate the performance of the proposed control technology using a different method; the first method used basic proportional integration (PI) controllers, and the second method used adaptive proportional integration (PI) controllers, i.e., an Artificial Neural Network (ANN).

scholarly journals An Optimal Longitudinal Control Strategy of Platoons Using Improved Particle Swarm Optimization

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Zhizhou Wu ◽  
Zhibo Gao ◽  
Wei Hao ◽  
Jiaqi Ma
Keyword(s):  
Particle Swarm Optimization ◽  
Control Strategy ◽  
Ride Comfort ◽  
Particle Swarm ◽  
Experimental Simulation ◽  
Driving Safety ◽  
Relative Speed ◽  
Longitudinal Control ◽  
Swarm Optimization ◽  
Improved Particle Swarm Optimization

Most existing longitudinal control strategies for connected and automated vehicles (CAVs) have unclear adaptability without scientific analysis regarding the key parameters of the control algorithm. This paper presents an optimal longitudinal control strategy for a homogeneous CAV platoon. First of all, the CAV platoon models with constant time-headway gap strategy and constant spacing gap strategy were, respectively, established based on the third-order linear vehicle dynamics model. Then, a linear-quadratic optimal controller was designed considering the perspectives of driving safety, efficiency, and ride comfort with three performance indicators including vehicle gap error, relative speed, and desired acceleration. An improved particle swarm optimization algorithm was used to optimize the weighting coefficients for the controller state and control variables. Based on the Matlab/Simulink experimental simulation, the analysis results show that the proposed strategy can significantly reduce the gap error and relative speed and improve the flexibility and initiative of the platoon control strategy compared with the unoptimized strategies. Sensitivity analysis was provided for communication lag and actuator lag in order to prove the applicability and effectiveness of this proposed strategy, which will achieve better distribution of system performance.

Constant force control for aluminum wheel hub grinding based on ESO + backstepping

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Shijie Dai ◽  
Yufeng Zhao ◽  
Wenbin Ji ◽  
Jiaheng Mu ◽  
Fengbao Hu
Keyword(s):  
Control Strategy ◽  
Force Control ◽  
Control Method ◽  
Response Speed ◽  
Backstepping Control ◽  
Constant Force ◽  
Content Type ◽  
Disturbance Rejection Control ◽  
The Stability ◽  
Differential Control

Purpose This paper aims to present a control method to realize the constant force grinding of automobile wheel hub. Design/methodology/approach A constant force control strategy combined by extended state observer (ESO) and backstepping control is proposed. ESO is used to estimate the total disturbance to improve the anti-interference and stability of the system and Backstepping control is used to improve the response speed of the system. Findings The simulation and grinding experimental results show that, compared with the proportional integral differential control and active disturbance rejection control, the designed controller can improve the dynamic response performance and anti-interference ability of the system and can quickly track the expected force and improve the grinding quality of the hub surface. Originality/value The main contribution of this paper lies in the proposed of a new constant force control strategy, which significantly improved the stability and precision of grinding force.

Application of Center Manifold Theory to Regulation of a Flexible Beam

1997 ◽  
Vol 119 (2) ◽  
pp. 158-165 ◽  
Author(s):  
Amir Khajepour ◽  
M. Farid Golnaraghi ◽  
Kirsten A. Morris
Keyword(s):  
Control Strategy ◽  
Center Manifold ◽  
Flexible Beam ◽  
Trial And Error ◽  
Center Manifold Theory ◽  
Control Techniques ◽  
Lumped Parameter ◽  
The Stability ◽  
Frequency Relationship ◽  
Manifold Theory

In this paper we consider the problem of regulation of a flexible lumped parameter beam. The controller is an active/passive mass-spring-dashpot mechanism which is free to slide along the beam. In this problem the plant/controller equations are coupled and nonlinear, and the linearized equations of the system have two uncontrollable modes associated with a pair of pure imaginary eigenvalues. As a result, linear control techniques as well as most conventional nonlinear control techniques can not be applied. In earlier studies Golnaraghi (1991) and Golnaraghi et al. (1994) a control strategy based on Internal resonance was developed to transfer the oscillatory energy from the beam to the slider, where it was dissipated through controller damping. Although these studies provided very good understanding of the control strategy, the analytical method was based on perturbation techniques and had many limitations. Most of the work was based on numerical techniques and trial and error. In this paper we use center manifold theory to address the shortcomings of the previous studies, and extend the work to a more general control law. The technique is based on reducing the dimension of system and simplifying the nonlinearities using center manifold and normal forms techniques, respectively. The simplified equations are used to investigate the stability and to develop a relation for the optimal controller/plant natural frequencies at which the maximum transfer of energy occurs. One of the main contributions of this work is the elimination of the trial and error and inclusion of damping in the optimal frequency relationship.

Technology and Effectiveness of Cast Iron Treatment by Gas Injection

2010 ◽  
Vol 457 ◽  
pp. 459-464
Author(s):  
Edis B. Ten
Keyword(s):  
Cast Iron ◽  
Gas Injection ◽  
Small Diameter ◽  
Multiple Use ◽  
Positive Effects ◽  
Injection Treatment ◽  
The Stability ◽  
Injection Technology ◽  
Stability Regime ◽  
Structure Stabilization

In this work the development of the technology and equipment for gas injection treatment of cast iron by inert gas (nitrogen) is presented. The equipment includes the plunging lance as a lined steel pipe with nozzles. The nozzles are thin channels, which are lined by ceramic tubes with small-diameter. The lance has a multiple use, as it has calibrated channel sizes, and provide the stability regime of gas injection treatment. The characteristic of the gas injection technology consists of blowing of melt by gas, which is injected into the liquid cast iron through thin jet with a speed near to the velocity of sound. In this case, the dispersion of gas jets in small-sized bubbles is reached, therefore the refining effectiveness increases. The gas injection treatment shows the promotion of casting properties, improvement of homogeneity and fineness of structure, stabilization or increasing of mechanical properties, decreasing of casting defectiveness. The positive effects of the gas injection treatment is the result of complex action of the injecting gas into the cast iron melt. Together with refining and homogenizing action at specified conditions, it offers the modifying and alloying effects also.

scholarly journals Competition Law and State Aid for Failing Banks in the EU and its Specific Implications for CEE Member States

2016 ◽  
Vol 9 (14) ◽  
pp. 145-157
Author(s):  
Virág Blazsek
Keyword(s):  
European Union ◽  
State Aid ◽  
Common Market ◽  
Competition Authority ◽  
The European Union ◽  
Member States ◽  
Positive Effects ◽  
The Stability ◽  
Bank Bailouts ◽  
The Eu

The bank bailouts following the global financial crisis of 2008 have been subject to prior approval of the European Commission (EC), the competition authority of the European Union. The EC was reluctant to reject rescue efforts directed at failing banks and so it consistently approved all such requests submitted by Member States. Out of the top twenty European banks, the EC authorized State aid to at least twelve entities. In this context, the paper outlines the gradually changing interpretation of EU State aid rules, the “temporary and extraordinary rules” introduced starting from late 2008, and the extension of the “no-State aid” category. The above shifts show that the EC itself deflected from relevant EU laws in order to systemically rescue important banks in Europe and restore their financial stability. The paper argues that bank bailouts and bank rescue packages by the State have led to different effects on market structures and consumer welfare in the Eurozone and non-Eurozone areas, mostly the Eastern segments of the European Union. As such, it is argued that they are inconsistent with the European common market. Although the EC tried to minimize the distortion of competition created as a result of the aforementioned case law primarily through the application of the principle of exceptionality and different compensation measures, these efforts have been at least partially unsuccessful. Massive State aid packages, the preferential treatment of the largest, or systemically important, banks through EU State aid mechanisms – almost none of which are Central and Eastern European (CEE) – may have led to the distortion of competition on the common market. That is so mainly because of the prioritization of the stability of the financial sector and the Euro. The paper argues that State aid for failing banks may have had important positive effects in the short run, such as the promotion of the stability of the banking system and the Euro. In the longrun however, it has contributed to the unprecedented sovereign indebtedness in Europe, and contributed to an increased economic and political instability of the EU, particularly in its most vulnerable CEE segment.

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