Transient Vibration and Feedback Control of an Inductrack Maglev System

2020 ◽  
Author(s):  
Ruiyang Wang ◽  
Bingen Yang ◽  
Hao Gao
Keyword(s):  
Steady State ◽  
Feedback Control ◽  
Dynamic System ◽  
Permanent Magnets ◽  
Preliminary Investigation ◽  
Lookup Table ◽  
Lumped Mass ◽  
Transient Vibration ◽  
Transient Model ◽  
Halbach Arrays

Abstract As a new strategy for magnetic levitation envisioned in 1990s, the Inductrack system with permanent magnets (PMs) aligned in Halbach arrays has been intensively studied and applied in many projects. Due to the nonlinear, time-varying electro-magneto-mechanical coupling in such a system, the dynamic behaviors are complicated with transient responses, which in most cases can hardly be predicted with fidelity by a steady-state Inductrack model. Presented in this paper is a benchmark 2-DOF transient Inductrack model, which is derived from the first laws of nature, without any assumed steady-state quantities. It is shown that the dynamic response of the Inductrack dynamic system is governed by a set of nonlinear integro-differential equations. As demonstrated in numerical simulations with the transient model, unstable vibrations in the levitation direction occur when the traveling speed of the vehicle exceeds a threshold. To resolve this instability issue, feedback control is implemented in the Inductrack system. In the development, an assembly of Halbach arrays and active coils that are wound on the PMs is proposed to achieve a controllable source magnetic field. In this preliminary investigation, the proposed control system design process takes two main steps. First, a PID controller is set and tuned based on a simple lumped-mass dynamic system. Second, the nonlinear force-current correlation is obtained from a lookup table that is pre-calculated by steady-state truncation of the full transient Inductrack model. With the implemented feedback control algorithms, numerical examples display that the motion of the vehicle in levitation direction can be effectively stabilized at different traveling speeds. Although only a 2-DOF transient model is used here, the modeling technique and the controller design approach developed in this work are potentially applicable to more complicated models of Inductrack Maglev systems.

Nonlinear Feedback Control of the Inductrack System Based on a Transient Model

2021 ◽  
Author(s):  
Ruiyang Wang ◽  
Bingen (Ben) Yang ◽  
Hao Gao
Keyword(s):  
Feedback Control ◽  
Permanent Magnets ◽  
Control Method ◽  
Control Law ◽  
Operating Speed ◽  
Nonlinear Feedback ◽  
Transient Model ◽  
Mechanical Coupling ◽  
Wide Range ◽  
Halbach Arrays

Abstract As a new strategy for magnetic levitation envisioned in the 1990s, the Inductrack system with Halbach arrays of permanent magnets has been intensively researched. The previous investigations discovered that an uncontrolled Inductrack system may be unstable even if the vehicle travels well below its operating speed and that instability can be persistent near and beyond the operating speed. It is therefore necessary to stabilize the system for safety and reliability. With strong nonlinearities and complicated electro-magneto-mechanical coupling, however, the transient response of such a dynamic system is difficult to predict with fidelity. Because of this, model-based feedback control of Inductrack systems has not been well addressed. In this paper, by taking advantage of a recently available 2-DOF transient model, a new feedback control method for Inductrack systems is proposed. In the control system development, active Halbach arrays are used as an actuator, and a feedback control law, which combines a properly tuned PID controller and a nonlinear force-current mapping function, is created. The proposed control law is validated in numerical examples, where the transient motion of an Inductrack vehicle traveling at constant speed is considered. As shown in the simulation, the control law efficiently stabilizes the Inductrack system in a wide range of the operating speed, and in the meantime, it renders a smooth system output (real-time levitation gap) with fast convergence to any prescribed reference input (desired levitation gap).

Transient Response of Inductrack Systems for Maglev Transport: Part I—A New Transient Model

2020 ◽  
Vol 142 (3) ◽  
Author(s):  
Ruiyang Wang ◽  
Bingen Yang
Keyword(s):  
Transient Response ◽  
Degrees Of Freedom ◽  
Permanent Magnets ◽  
Magnetic Interaction ◽  
Response Analysis ◽  
Governing Equations ◽  
Interaction Forces ◽  
Transient Model ◽  
Two Degrees Of Freedom ◽  
Halbach Arrays

Abstract As a new strategy for magnetic levitation, Inductrack systems with Halbach arrays of permanent magnets have been applied to Maglev trains and intensively researched in various projects. In an Inductrack system, the magnetic interaction forces are coupled with the motion of a moving vehicle carrying Halbach arrays, which in many situations results in complicated transient behaviors of the system. In this two-part paper, a new transient model of two degrees-of-freedom for Inductrack systems is proposed. The highlight of this work is that the transient model is developed based on the fundamental principle of physics, without the assumption of steady-state quantities and averaged magnetic forces and with the finite dimensions of Halbach arrays in consideration. In Part I, the transient model is derived through the establishment of a set of nonlinear integro-differential governing equations, and the magnetic interaction forces in the Inductrack system are determined in analytical form. In Part II, the solution of the governing equations, model validation with the previous results in the literature, and transient response analysis via numerical simulation is presented. Although only two degrees-of-freedom have been considered, the approach of modeling and analysis presented in this paper can be extended to general cases of multi-degrees-of-freedom.

An Application of Active Dynamic Absorber to the Milling Process and its Experimental Verification

1993 ◽  
Author(s):  
K. J. Liu ◽  
Keith E. Rouch
Keyword(s):  
Feedback Control ◽  
Element Model ◽  
Milling Process ◽  
Control Technique ◽  
Structure Model ◽  
Lumped Mass ◽  
Annular Ring ◽  
Optimal Control Algorithms ◽  
Machine Tool Chatter ◽  
Dynamic Absorber

Abstract In order to reach the inside surfaces of some workpieces, a prototype for milling extension is developed. The milling extension has a low static stiffness and is prone to machine tool chatter, therefore vibration control in this type of machining is of importance. The paper proposes the application of an active dynamic absorber to the milling process. A finite element model for the milling extension with consideration of the cutting dynamics is developed. An annular ring serving as the dynamic absorber mass is connected to the main system through active force generating systems which are piezoelectric translators functioning as actuators. The annular ring and the actuators are functioning as an active dynamic absorber in the theory to suppress the vibration of the milling system. Optimal control algorithms are used to calculate the Kalman feedback control for the equivalent lumped-mass milling structure model. Transient responses of the system are obtained. Oscillation of the milling extension equipped with the active dynamic absorber is attenuated appreciably, therefore the surface finish of a workpiece is improved. Harmonic responses are also obtained with and without the feedback control to show the superiority of the active control technique. A proof-of-concept experiment is designed and conducted to verify the theoretical prediction. Comparisons between the simulation and experimental results are made.

Vibration Behavior and Serviceability of Arched Prestressed Concrete Truss Due to Human Activity

2018 ◽  
Vol 18 (12) ◽  
pp. 1850146 ◽  
Author(s):  
Jiang Li ◽  
Jiepeng Liu ◽  
Liang Cao ◽  
Y. Frank Chen
Keyword(s):  
Steady State ◽  
Prestressed Concrete ◽  
Natural Frequencies ◽  
Current Trend ◽  
Threshold Values ◽  
Transient Vibration ◽  
Vibration Behavior ◽  
Detailed Evaluation ◽  
Floor Systems ◽  
Floor Vibration

The current trend toward longer spans and lighter floor systems, combined with reduced damping and new activities, have resulted in an increasing complaints on floor vibration from building owners and occupants. Heel-drop, jumping, and walking impacts, which may lead to discomfort problems in daily life, were imposed on a large-span arched prestressed concrete truss (APT) girder system studied. The natural frequencies, peak acceleration, average root-mean-square acceleration (ARMS), maximum transient vibration value (MTVV), and perception factor for the girder were obtained and checked against the existing codes and standards. The purpose of this paper is to provide researchers and engineers with a detailed evaluation on the vibration behavior of the APT girder under different human activities, with a comprehensive review on the relevant criteria and some suggestions. Lastly, the following threshold peak accelerations are suggested: 650[Formula: see text]mm/s2 for transient heel-drop impact, 1450[Formula: see text]mm/s2 for transient jumping impact, and 250[Formula: see text]mm/s2 for steady-state walking. In addition, the threshold values of 90[Formula: see text]mm/s2 and 50[Formula: see text]mm/s2 are suggested for MTVV and ARMS, respectively, under steady-state walking.

scholarly journals Reliability Analysis of a Filtering Reducer under the Discrete Space Environmental Shocks

2014 ◽  
Vol 6 ◽  
pp. 921720 ◽  
Author(s):  
Jing Lu ◽  
Zhonglai Wang ◽  
Wei Chen ◽  
Xuefei Zhang ◽  
Hao Liu
Keyword(s):  
Differential Equations ◽  
Dynamic System ◽  
Mechanism Design ◽  
Reliability Analysis ◽  
Dynamic Model ◽  
Space Environment ◽  
Newmark Method ◽  
Lumped Mass ◽  
Dynamic Reliability ◽  
Environmental Shocks

Dynamic reliability analysis of a filtering reducer is performed by accounting for discrete shocks from the space environment. Gears are considered as the lumped mass and meanwhile the meshing between different gears is equivalent to a dynamic system consisting of springs and dampers during construction of the dynamic model. The Newmark method is employed to resolve differential equations, and then the additional acceleration could be obtained, caused by shocks to the filtering reducer. Dynamic reliability analysis is conducted with the help of the Simulink tool for the outputs. The results are hopefully useful for spacecraft mechanism design.

Prediction of Deswirled Radial Inflow in Rotating Cavities With Hysteresis

2013 ◽  
Vol 135 (4) ◽  
Author(s):  
David May ◽  
John W. Chew ◽  
Timothy J. Scanlon
Keyword(s):  
Steady State ◽  
Flow Characteristic ◽  
Steady State Solution ◽  
Negative Resistance ◽  
Operating Conditions ◽  
Operating Characteristics ◽  
Transient Model ◽  
Rotating Cavity ◽  
1D Model ◽  
Flow Effects

Deswirl nozzles are sometimes used in turbomachinery to reduce the pressure drop when air is drawn radially inwards through a rotating cavity. However, this can lead to nonunique steady state solutions with operating conditions achieved depending on how the steady point is approached. In the present study, a novel transient, 1D model of flow in a rotating cavity has been created. The model was validated for two distinct cases: a smooth rectangular cavity and an engine-representative case. The transient model reproduced experimentally observed hysteresis, discontinuity in operating characteristics, and regions where no steady-state solution could be found. In the case of the engine-representative rig, part of the flow characteristic could not be obtained in testing. This was determined to be due to the interaction of the negative resistance region of the vortex and the flow-modulating valve characteristic. Measures that allow the full capture of the flow characteristic in rig testing are identified. These results show that inclusion of transient rotating flow effects can be important in turbomachinery air systems modeling. To the authors' knowledge, this is the first model to capture these effects.

scholarly journals Revealing Hidden Debottlenecking Potential in Flare Systems on Offshore Facilities Using Dynamic Simulations -- a Preliminary Investigation

2020 ◽  
Author(s):  
Ana Xiao Outomuro Somozas ◽  
Rudi P. Nielsen ◽  
Marco Maschietti ◽  
Anders Andreasen
Keyword(s):  
Steady State ◽  
Peak Flow ◽  
Preliminary Investigation ◽  
System Size ◽  
Dynamic Simulations ◽  
Wide Range ◽  
Total Plant ◽  
Steady State Simulation ◽  
State Case

Three flare systems are modeled and total plant depressurization is investigated using dynamic simulations in order to access the debottlenecking potential. Usually steady-state simulation of the flare network is used for sizing and rating of the flare system. By using dynamic simulations effects from line packing in the flare system can be studied. The results show that peak flow during a dynamic simulations is significantly lower than the peak flow used in a steady-state case. <br>The three systems investigated span a wide range in flare system size, both in terms of number of process segments disposing into the flare network, in terms of peak design rate and the flare network pipe dimensions and total hold-up volume. Generally, it is observed that the larger the flare system, the larger debottlenecking potential.

Transient Response of Inductrack Systems for Maglev Transport: Part II—Solution and Dynamic Analysis

2020 ◽  
Vol 142 (3) ◽  
Author(s):  
Ruiyang Wang ◽  
Bingen Yang
Keyword(s):  
Steady State ◽  
Dynamic Analysis ◽  
Transient Response ◽  
Numerical Procedure ◽  
Steady State Response ◽  
Governing Equations ◽  
Transient Model ◽  
State Response ◽  
Proposed Model ◽  
Non Linear

Abstract In Part I of this two-part paper, a new benchmark transient model of Inductrack systems is developed. In this Part II, the proposed model, which is governed by a set of non-linear integro-differential governing equations, is used to predict the dynamic response of Inductrack systems. In the development, a state-space representation of the non-linear governing equations is established and a numerical procedure with a specific moving circuit window for transient solutions is designed. The dynamic analysis of Inductrack systems with the proposed model has two major tasks. First, the proposed model is validated through comparison with the noted steady-state results in the literature. Second, the transient response of an Inductrack system is simulated and analyzed in several typical dynamic scenarios. The steady-state response results predicted by the new model agree with those obtained in the previous studies. On the other hand, the transient response simulation results reveal that an ideal steady-state response can hardly exist in those investigated dynamic scenarios. It is believed that the newly developed transient model provides a useful tool for dynamic analysis of Inductrack systems and for in-depth understanding of the complicated electro-magneto-mechanical interactions in this type of dynamic systems.

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