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Danfeng Zhou - One of the best experts on this subject based on the ideXlab platform.

  • Suppression of the Maglev Vehicle-Track Coupled Self-Excited Vibration Using Two Gap Sensors
    2019 Chinese Control Conference (CCC), 2019
    Co-Authors: Danfeng Zhou, Zhaoyu Guo
    Abstract:

    Due to the flexibility of the steel track, self-Excited Vibration between the electromagnet and the track may occur when the EMS (electromagnetic suspension) urban maglev train is suspending above the track in a standstill. The self-Excited Vibration produces annoying high frequency noise, decreases the ride comfort of the maglev vehicle, and may cause fatigues to track structures. Therefore, in a commercial maglev line, the track induced high frequency self-Excited Vibration must be eliminated. In this paper, a new configuration of the gap sensors for the suspension system is proposed. In this configuration, two gap sensors are employed to measure the suspension gaps at different locations of the electromagnet, which is different from the conventional configuration of the urban maglev system in which only one gap sensor is used at the terminal of the electromagnet. Using two gap sensors, the deformations of the track can be measured at different locations, and by appropriate selection of the distance between these two sensors, the vibratory components of the track deformation included in the measured gap signals may be greatly cancelled by adding them together, leading to possible elimination of the self-Excited Vibration. The modeling of the multi-span maglev track and the principle of the proposed scheme are both investigated through theoretical analysis; a simulation is further undertaken to validate the effectiveness of this scheme. The configuration proposed in this paper is easy to realize in the urban maglev vehicle, and it is also benefit for decreasing the Vibration of the suspension system in the presence of track irregularities when the train is traveling.

  • Maglev self-Excited Vibration suppression with a virtual sky-hooked damper
    Journal of Central South University, 2016
    Co-Authors: Danfeng Zhou, Lianchun Wang
    Abstract:

    This work addresses the problem of self-Excited Vibration, which degrades the stability of the levitation control, decreases the ride comfort, and restricts the construction cost of maglev system. Firstly, a minimum model containing a flexible bridge and a single levitation unit is presented. Based on the simplified model, the principle underlying the self-Excited Vibration is explored. After investigations about the energy transmission between the levitation system and bridge, it is concluded that the increment of modal damping can dissipate the accumulated energy by the bridge and the self-Excited Vibration may be avoided. To enlarge the equivalent modal damping of bridge, the sky-hooked damper is adopted. Furthermore, to avoid the hardware addition of real sky-hooked damper, considering the fact that the electromagnet itself is an excellent actuator that is capable of providing sufficiently fast and large force acting on the bridge to emulate the influence of the real sky-hooked damper, the technique of the virtual sky-hooked damper is proposed. The principle underlying the virtual sky-hooked damper by electromagnet is explored and the vertical velocity of bridge is estimated. Finally, numerical and experimental results illustrating the stability improvement of the vehicle-bridge interaction system are provided.

  • the active control of maglev stationary self Excited Vibration with a virtual energy harvester
    IEEE Transactions on Industrial Electronics, 2015
    Co-Authors: Danfeng Zhou, Peng Cui, Lianchun Wang
    Abstract:

    This paper addresses the active control of stationary self-Excited Vibration, which degrades the stability of the levitation control, decreases the ride comfort, and restricts the construction cost of the maglev system. First, a minimum interaction model containing a flexible bridge and a single levitation unit is presented. Based on the minimum interaction model, the principle underlying the self-Excited Vibration is explored. It shows that the active property of the levitation system is the root of self-Excited Vibration. Consider that the energy of Vibration may be absorbed by the electromagnetic energy harvester (EEH), so that a technique applying it to the bridge is proposed, and the stability of the combined system is analyzed. However, its hardware structure is complicated, and the cost of construction is prohibitive. Then the novel conception of the virtual EEH is brought forward, which uses the electromagnetic force to emulate the force of a real energy harvester acting on the bridge. With the estimation of the vertical velocity of the bridge and the frequency of Vibration, the self-oscillatory is avoided as well by adding an extra control instruction to the electromagnet. After building the overall dynamic model with details, numerical simulations and field experiments are carried out, and the results illustrating the improvement of stability are provided and analyzed.

  • The Modeling and Analysis for the Self-Excited Vibration of the Maglev Vehicle-Bridge Interaction System
    Mathematical Problems in Engineering, 2015
    Co-Authors: Danfeng Zhou, Lianchun Wang
    Abstract:

    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.

  • Self-Excited Vibration problems of maglev vehicle-bridge interaction system
    Journal of Central South University, 2014
    Co-Authors: Danfeng Zhou
    Abstract:

    The self-Excited Vibration problems of maglev vehicle-bridge interaction system were addressed, which greatly degrades the stability of the levitation control, decreases the ride comfort, and restricts the cost of the whole system. Firstly, the coupled model containing the quintessential parts was built, and the mechanism of self-Excited Vibration was explained in terms of energy transmission from levitation system to bridge. Then, the influences of the parameters of the widely used integral-type proportion and derivation (PD) controller and the delay of signals on the stability of the interaction system were analyzed. The result shows that the integral-type PD control is a nonoptimal approach to solve the self-Excited Vibration completely. Furthermore, the differential-type PD controller can guarantee the passivity of levitation system at full band. However, the differentiation of levitation gap should be filtered by a low-pass filter due to noise of gap differentiation. The analysis indicates that a well tuned low-pass filter can still keep the coupled system stable.

Lianchun Wang - One of the best experts on this subject based on the ideXlab platform.

  • Maglev self-Excited Vibration suppression with a virtual sky-hooked damper
    Journal of Central South University, 2016
    Co-Authors: Danfeng Zhou, Lianchun Wang
    Abstract:

    This work addresses the problem of self-Excited Vibration, which degrades the stability of the levitation control, decreases the ride comfort, and restricts the construction cost of maglev system. Firstly, a minimum model containing a flexible bridge and a single levitation unit is presented. Based on the simplified model, the principle underlying the self-Excited Vibration is explored. After investigations about the energy transmission between the levitation system and bridge, it is concluded that the increment of modal damping can dissipate the accumulated energy by the bridge and the self-Excited Vibration may be avoided. To enlarge the equivalent modal damping of bridge, the sky-hooked damper is adopted. Furthermore, to avoid the hardware addition of real sky-hooked damper, considering the fact that the electromagnet itself is an excellent actuator that is capable of providing sufficiently fast and large force acting on the bridge to emulate the influence of the real sky-hooked damper, the technique of the virtual sky-hooked damper is proposed. The principle underlying the virtual sky-hooked damper by electromagnet is explored and the vertical velocity of bridge is estimated. Finally, numerical and experimental results illustrating the stability improvement of the vehicle-bridge interaction system are provided.

  • the active control of maglev stationary self Excited Vibration with a virtual energy harvester
    IEEE Transactions on Industrial Electronics, 2015
    Co-Authors: Danfeng Zhou, Peng Cui, Lianchun Wang
    Abstract:

    This paper addresses the active control of stationary self-Excited Vibration, which degrades the stability of the levitation control, decreases the ride comfort, and restricts the construction cost of the maglev system. First, a minimum interaction model containing a flexible bridge and a single levitation unit is presented. Based on the minimum interaction model, the principle underlying the self-Excited Vibration is explored. It shows that the active property of the levitation system is the root of self-Excited Vibration. Consider that the energy of Vibration may be absorbed by the electromagnetic energy harvester (EEH), so that a technique applying it to the bridge is proposed, and the stability of the combined system is analyzed. However, its hardware structure is complicated, and the cost of construction is prohibitive. Then the novel conception of the virtual EEH is brought forward, which uses the electromagnetic force to emulate the force of a real energy harvester acting on the bridge. With the estimation of the vertical velocity of the bridge and the frequency of Vibration, the self-oscillatory is avoided as well by adding an extra control instruction to the electromagnet. After building the overall dynamic model with details, numerical simulations and field experiments are carried out, and the results illustrating the improvement of stability are provided and analyzed.

  • The Modeling and Analysis for the Self-Excited Vibration of the Maglev Vehicle-Bridge Interaction System
    Mathematical Problems in Engineering, 2015
    Co-Authors: Danfeng Zhou, Lianchun Wang
    Abstract:

    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.

Ni Tianxin - One of the best experts on this subject based on the ideXlab platform.

  • Bifurcation and factors influence analysis on self-Excited Vibration of tire tread:
    Journal of Vibration and Control, 2016
    Co-Authors: Zuo Shuguang, Ni Tianxin
    Abstract:

    The purpose behind this work is to discuss dynamic stability when self-Excited Vibration occurs on tire tread. First of all, a suspension-tire-tread model has been built for simulation, and the result shows the existence of self-Excited Vibration on tire tread under particular conditions. A six-component test of the wheel indicates that self-Excited Vibration often takes place on tire tread when the vehicle travels straightaway at high speed. Then, through bifurcation analysis of tire tread, we found that the speed of the vehicle and slip angle of the wheel play significant roles in Vibration generation. Within the lateral speed component caused by the tiny slip angle, equivalent damping of system turns to negative and thus provides enough energy to be consumed by obstructions. In order to investigate the influence of this self-Excited Vibration on the system, the system model has been simulated with different parameters, such as vehicle speed, vertical load, and tire pressure. The result explains differe...

Zuo Shuguang - One of the best experts on this subject based on the ideXlab platform.

  • Bifurcation and factors influence analysis on self-Excited Vibration of tire tread:
    Journal of Vibration and Control, 2016
    Co-Authors: Zuo Shuguang, Ni Tianxin
    Abstract:

    The purpose behind this work is to discuss dynamic stability when self-Excited Vibration occurs on tire tread. First of all, a suspension-tire-tread model has been built for simulation, and the result shows the existence of self-Excited Vibration on tire tread under particular conditions. A six-component test of the wheel indicates that self-Excited Vibration often takes place on tire tread when the vehicle travels straightaway at high speed. Then, through bifurcation analysis of tire tread, we found that the speed of the vehicle and slip angle of the wheel play significant roles in Vibration generation. Within the lateral speed component caused by the tiny slip angle, equivalent damping of system turns to negative and thus provides enough energy to be consumed by obstructions. In order to investigate the influence of this self-Excited Vibration on the system, the system model has been simulated with different parameters, such as vehicle speed, vertical load, and tire pressure. The result explains differe...

  • Study on Dynamics of Polygonal Wear of Automotive Tire Caused by Self-Excited Vibration
    Mathematical Problems in Engineering, 2014
    Co-Authors: Zuo Shuguang, Duan Xianglei
    Abstract:

    Considering the underlying reason of tire polygonal wear, a unified mechanical tire model is developed to analyze the different Vibration properties between the driving wheel and follower wheel. And the LuGre dynamic friction model is applied to determine the frictional forces between the wheel with a slip angel and the road. Through the stability analysis with Lyapunov theory, it is found that tread self-Excited Vibration is periodic oscillation caused by Hopf bifurcation. The analysis of the lateral Vibration of driving wheel shows that the tread Vibration system loses its stability and self-Excited Vibration occurs when the wheel is rolling at a high speed, is over-loaded, is having a large toe-in angle, or is under a low tire pressure. On this basis, the dynamic behaviors of the driving and follower wheels are distinguished with different slip rates by the numerical simulation. Compared with the dynamic behaviors of the follower wheel under the same condition, the self-Excited Vibration occurs on the driving wheel with more limited parameter scope, lower oscillation energy, and lower occurrence, which explains why the polygonal wear is less likely to occur on the driving wheel.

Ashwin A Seshia - One of the best experts on this subject based on the ideXlab platform.

  • an auto parametrically Excited Vibration energy harvester
    Sensors and Actuators A-physical, 2014
    Co-Authors: Yu Jia, Ashwin A Seshia
    Abstract:

    Parametric resonance, as a resonant amplification phenomenon, is a superior mechanical amplifier than direct resonance and has already been demonstrated to possess the potential to offer over an order of magnitude higher power output for Vibration energy harvesting than the conventional direct excitation. However, unlike directly Excited systems, parametric resonance has a minimum threshold amplitude that must be attained prior to its activation. The authors have previously presented the addition of initial spring designs to minimise this threshold, through non-resonant direct amplification of the base excitation that is subsequently fed into the parametric resonator. This paper explores the integration of auto-parametric resonance, as a form of resonant amplification of the base excitation, to further minimise this activation criterion and realise the profitable regions of parametric resonance at even lower input acceleration levels. Numerical and experimental results have demonstrated in excess of an order of magnitude reduction in the initiation threshold amplitude for an auto-parametric resonator (∼0.6 ms−2) as well as several folds lower for a parametric resonator with a non-resonant base amplifier (∼4.0 ms−2), as oppose to a sole parametric resonator without any threshold reduction mechanisms (10's ms−2). Therefore, the superior power performance of parametric resonance over direct resonance has been activated and demonstrated at much lower input levels.

  • a parametrically Excited Vibration energy harvester
    Journal of Intelligent Material Systems and Structures, 2014
    Co-Authors: Yu Jia, Jize Yan, Kenichi Soga, Ashwin A Seshia
    Abstract:

    In the arena of Vibration energy harvesting, the key technical challenges continue to be low power density and narrow operational frequency bandwidth. While the convention has relied upon the activation of the fundamental mode of resonance through direct excitation, this article explores a new paradigm through the employment of parametric resonance. Unlike the former, oscillatory amplitude growth is not limited due to linear damping. Therefore, the power output can potentially build up to higher levels. Additionally, it is the onset of non-linearity that eventually limits parametric resonance; hence, this approach can also potentially broaden the operating frequency range. Theoretical prediction and numerical modelling have suggested an order higher in oscillatory amplitude growth. An experimental macro-sized electromagnetic prototype (practical volume of ~1800 cm3) when driven into parametric resonance, has demonstrated around 50% increase in half power band and an order of magnitude higher peak power density normalised against input acceleration squared (293 mW cm23 m22 s4 with 171.5 mW at 0.57 m s22) in contrast to the same prototype directly driven at fundamental resonance (36.5 mW cm23 m22 s4 with 27.75 mW at 0.65 m s22). This figure suggests promising potentials while comparing with current state-of-the-art macro-sized counterparts, such as Perpetuum’s PMG-17 (119 mW cm23 m22 s4).