Dynamic Characteristics of Magnetically-Levitated Vehicle Systems

1997 ◽  
Vol 50 (11) ◽  
pp. 647-670 ◽  
Author(s):  
Y. Cai ◽  
S. S. Chen

The dynamic response of magnetically-levitated (maglev) ground transportation systems has important consequences for safety and ride quality, guideway design, and system costs. This article, which reviews various aspects of the dynamic characteristics, experiments and analysis, and design guidelines for maglev systems, discusses electrodynamic system (EDS) maglev vehicle stability, motion-dependent magnetic force components, guideway characteristics, vehicle/guideway interaction, ride quality, suspension control laws, aerodynamic loads and other excitations, and research needs. This review article includes 157 references.

2020 ◽  
Vol 10 (20) ◽  
pp. 7179
Author(s):  
Catalina González-Castaño ◽  
Carlos Restrepo ◽  
Roberto Giral ◽  
Enric Vidal-Idiarte ◽  
Javier Calvente

This paper analyzes the presence of undesired quantization-induced perturbations (QIP) in a dc-dc buck-boost converter using a two-loop digital current control. This work introduces design conditions regarding control laws gains and signal quantization to avoid the quantization effects due to the addition of the outer voltage loop in a digital current controlled converter. The two-loop controller is composed of a multisampled average current control (MACC) in the inner current-programmed loop and a proportional-integrator compensator at the external loop. QIP conditions have been evaluated through simulations and experiments using a digitally controlled pulse width modulation (DPWM) buck-boost converter. A 400 V 1.6 kW proof-of-concept converter has been used to illustrate the presence of QIP and verify the design conditions. The controller is programmed in a digital signal controller (DSC) TMS320F28377S with a DPWM with 8.96-bit equivalent resolution, a 12-bit ADC for current sampling, and a 12-bit ADC for voltage sampling or a 16-bit ADC for voltage error sampling.


Electronics ◽  
2021 ◽  
Vol 10 (16) ◽  
pp. 1886
Author(s):  
Younghoon Cho ◽  
Paul Jang

Fly-buck converter is a multi-output converter with the structure of a synchronous buck converter structure on the primary side and a flyback converter structure on the secondary side, and can be utilized in various applications due to its many advantages. In terms of control, the primary side of the fly-buck converter has the same structure as a synchronous buck converter, allowing the constant-on-time (COT) control to be applied to the fly-buck converter. However, due to the inherent energy transfer principle, the primary-side output voltage regulation of COT controlled fly-buck converters may be poor, which can deteriorate the overall converter performance. Therefore, the primary output capacitor must be carefully designed to improve the voltage regulation characteristics. In this paper, a theoretical analysis of the output voltage regulation in COT controlled fly-buck converter is conducted, and based on this, a design guideline for the primary output capacitor considering the output voltage regulation is presented. The validity of the analysis and design guidelines was verified using a 5 W prototype of the COT controlled fly-buck converter for telecommunication auxiliary power supply.


Author(s):  
Yamini Gourishankar ◽  
Frank Weisgerber

Abstract It is observed that calculating the wind pressures on structures involves more data retrieval from the ASCE standard than any subjective reasoning on the designer’s part. Once the initial design requirements are established, the procedure involved in the computation is straightforward. This paper discusses an approach to automate the process associated with wind pressure computation on one story and multi-story buildings using a data management strategy (implemented using the ORACLE database management system). In the prototype system developed herein, the designer supplies the design requirements in the form of the structure’s exposure type, its dimensions and the nature of occupancy of the structure. Using these requirements, the program retrieves the necessary standards data from an independently maintained database, and computes the wind pressures. The final output contains the wind pressures on the main wind force resisting system, and on the components and claddings, for wind blowing parallel and perpendicular to the ridge. The knowledge encoded in the system was gained from ASCE codes, design guidelines and as a result of interviews with various experts and practitioners. Several information modeling methodologies such as the entity relationship model, IDEF 1X, etc. were employed in the system analysis and design phase of this project. The prototype is implemented on an IBM PC using the ORACLE DBMS and the ‘C’ programming language. Appendix A illustrates a sample run.


2020 ◽  
Vol 68 (7) ◽  
pp. 2562-2570
Author(s):  
Mohamed A. G. Elsheikh ◽  
Nancy Y. Ammar ◽  
Amr M. E. Safwat

2012 ◽  
Vol 605-607 ◽  
pp. 626-629
Author(s):  
Xin Yu Zhang

This paper has analyzed the movement of the crank-rocker mechanism by a simple finite element model, to study the establishing of the model and the constraints imposed. It has simulated the movement by software ANSYS, and gets the results which is consistent to the theoretical analysis. It accesses kinematical and dynamic characteristics for the mechanism, and provides the necessary foundation to analysis and design of the complex machinery.


1991 ◽  
Vol 113 (3) ◽  
pp. 226-232 ◽  
Author(s):  
Ben Nagaraj ◽  
Mali Mahalingam

Flip Tape Automated Bond (FTAB) interconnect is one of the leading candidates for device to substrate interconnection in a high performance Multi-Chip Module (MCM). The TAB interconnect becomes a structural member in the MCM assembly, bearing both “mechanical” and “thermal” loads. Further, to accomplish high thermal performance in the assembly, physical contact to the device may be made under substantial contact pressures. The device may be supported by elastic structures to redistribute the interconnect forces. Finite Element Methods (FEM) are used to analyze the structural behavior of TAB interconnects under (i) the applied mechanical load to the device and (ii) the thermal loads due to the heat dissipation in the device. Variation of the force components on the TAB interconnects and the maximum failure criterion based on the stresses in the interconnects are reported. Effect of the support area and the modulus of the supporting element on the interconnects are discussed. Generic design guidelines are presented for flip TAB interconnect based MCM assembly.


2019 ◽  
Vol 16 (3) ◽  
pp. 172988141985097
Author(s):  
Xianliang Jiang ◽  
Huajie Hong

In the feedback control robotic systems, the repetitive control method has a high control performance for the track or elimination of the periodic signals. The promotion of the plug-in type configuration of the controller broadens the application range and applicability of the control method. In this article, a novel design algorithm based on the steady-state residual convergence ratio of the repetitive control system is proposed to improve the performance of the stabilized platform to resist the periodic perturbation. The basic structure and stable condition of the plug-in type repetitive control method are first introduced by applying the small gain theorem and the stability theorem for time-lag systems. Then the analysis of the convergence rate is utilized in constructing the basic index of the design algorithm of a plug-in type repetitive control system based on a steady-state residual convergence ratio. The parameters of the designed controller are checked by the validity condition of the plug-in type repetitive control system, and a simulation example is given to verify the effectiveness of the design algorithm. The article provides basic design guidelines and schemes for the design of the periodic disturbance suppression performance of the feedback control system. In the final physical prototype experiment, the prospective steady-state residual convergence ratio is basically achieved within the allowable range of error.


2019 ◽  
Vol 7 (1) ◽  
pp. 19-34 ◽  
Author(s):  
Mofetoluwa Fagbemi ◽  
Mario G. Perhinschi ◽  
Ghassan Al-Sinbol

Purpose The purpose of this paper is to develop and implement a general sensor model under normal and abnormal operational conditions including nine functional categories (FCs) to provide additional tools for the design, testing and evaluation of unmanned aerial systems within the West Virginia University unmanned air systems (UAS) simulation environment. Design/methodology/approach The characteristics under normal and abnormal operation of various types of sensors typically used for UAS control are classified within nine FCs. A general and comprehensive framework for sensor modeling is defined as a sequential alteration of the exact value of the measurand corresponding to each FC. Simple mathematical and logical algorithms are used in this process. Each FC is characterized by several parameters, which may be maintained constant or may vary during simulation. The user has maximum flexibility in selecting values for the parameters within and outside sensor design ranges. These values can be set to change at pre-defined moments, such that permanent and intermittent scenarios can be simulated. Sensor outputs are integrated with the autonomous flight simulation allowing for evaluation and analysis of control laws. Findings The developed sensor model can provide the desirable levels of realism necessary for assessing UAS behavior and dynamic response under sensor failure conditions, as well as evaluating the performance of autonomous flight control laws. Research limitations/implications Due to its generality and flexibility, the proposed sensor model allows detailed insight into the dynamic implications of sensor functionality on the performance of control algorithms. It may open new directions for investigating the synergistic interactions between sensors and control systems and lead to improvements in both areas. Practical implications The implementation of the proposed sensor model provides a valuable and flexible simulation tool that can support system design for safety purposes. Specifically, it can address directly the analysis and design of fault tolerant flight control laws for autonomous UASs. The proposed model can be easily customized to be used for different complex dynamic systems. Originality/value In this paper, information on sensor functionality is fused and organized to develop a general and comprehensive framework for sensor modeling at normal and abnormal operational conditions. The implementation of the proposed approach enhances significantly the capability of the UAS simulation environment to address important issues related to the design of control laws with high performance and desirable robustness for safety purposes.


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