Research and Development of Steady-State MPD Thrusters with Permanent Magnets and Multi Hollow Cathodes for In-Space Propulsion

2014 ◽  
Author(s):  
Tomoya Suzuki ◽  
Hirokazu Tahara
Keyword(s):  
Steady State ◽  
Research And Development ◽  
Permanent Magnets ◽  
Space Propulsion ◽  
Hollow Cathodes ◽  
Mpd Thrusters

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.

Recent progress in research and development of hollow cathodes for electric propulsion

2019 ◽  
Vol 3 (1) ◽  
Author(s):  
Dan R. Lev ◽  
Ioannis G. Mikellides ◽  
Daniela Pedrini ◽  
Dan M. Goebel ◽  
Benjamin A. Jorns ◽  
...  
Keyword(s):  
Research And Development ◽  
Electric Propulsion ◽  
Recent Progress ◽  
Hollow Cathodes

Designing Better, Cost-Effective Brain–Computer Interfaces

2015 ◽  
Vol 23 (4) ◽  
pp. 13-19 ◽  
Author(s):  
Chang S. Nam ◽  
Matthew Moore ◽  
Inchul Choi ◽  
Yueqing Li
Keyword(s):  
Steady State ◽  
Research And Development ◽  
Evoked Potential ◽  
Brain Computer Interface ◽  
Cost Effective ◽  
Computer Interface ◽  
Computer Interfaces ◽  
The Brain ◽  
Bci System ◽  
Users With Special Needs

Despite the increase in research interest in the brain–computer interface (BCI), there remains a general lack of understanding of, and even inattention to, human factors/ergonomics (HF/E) issues in BCI research and development. The goal of this article is to raise awareness of the importance of HF/E involvement in the emerging field of BCI technology by providing HF/E researchers with a brief guide on how to design and implement a cost-effective, steady-state visually evoked potential (SSVEP)–based BCI system. We also discuss how SSVEP BCI systems can be improved to accommodate users with special needs.

Research and Development of Bulk Anisotropic Nanograin Composite Rare Earth Permanent Magnets

2006 ◽  
Vol 13 ◽  
pp. 123-135 ◽  
Author(s):  
Sam LIU ◽  
Don LEE ◽  
Mei-qing HUANG ◽  
Ashil Higgins ◽  
Yu-hui SHEN ◽  
...  
Keyword(s):  
Rare Earth ◽  
Research And Development ◽  
Permanent Magnets

Use of permanent magnets to reduce anode losses in MPD thrusters

1994 ◽  
Vol 10 (4) ◽  
pp. 554-561 ◽  
Author(s):  
A. D. Gallimore ◽  
A. J. Kelly ◽  
R. G. Jahn
Keyword(s):  
Permanent Magnets ◽  
Mpd Thrusters

Analysis of Self-field MPD Thrusters for Designing a Megawatt-class In-space Propulsion System

2014 ◽  
Author(s):  
Ikkoh Funaki ◽  
Ken Kubota ◽  
Akira Kawasaki ◽  
Yoshihiro Okuno ◽  
Kenji Miyazaki ◽  
...  
Keyword(s):  
Propulsion System ◽  
Space Propulsion ◽  
Mpd Thrusters
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