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34th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit, 1998

作者： Ho, Nhut Lozano, Paulo Mangoubi, Kami Martinez-Sanchez, Manual Department of Mechanical Engineering M.I.T. and Control and Dynamical Systems Division C. S. Draper Laboratory CambridgeMA02139 United States Department of Aeronautics and Astronautics Massachusetts Institute of Technology CambridgeMA02139 United States Control and Dynamical Systems Division C. S. Draper Laboratory CambridgeMA02139 United States

A Vehicle Health Monitoring (VHM) system is designed to detect and isolate failures in the engines of Reusable Launch Vehicles (RLV). This VHM system takes into account engine failures in both sensors and valves, as well as internal components such as turbopumps, injectors, and the combustion chamber. The algorithm of the VHM system is model based. Specifically, using information from a thermodynamic model of the engine together with sensor measurements, a Kalman filter (KF) is designed to predict sensor outputs. The residual, or the difference between the predicted and actual measurement, is used by several statistical tests to detect the presence of a failure, and to categorize the failure as a sensor/valve failure or an internal component failure. Sensor and valve failures are then isolated using the Generalized Likelihood Ratio Test (GLRT). Internal component failures, on the other hand, are isolated using the Multiple Model (MM) method. The proposed methodology can be used for online Failure Detection and Isolation (FDI) as well as for postflight analysis. At the engine design stage, it can help determine the detectability and distinguishability of failures given a candidate sensor configuration. The FDI algorithms are applied to a simulation of the Space Shuttle Main Engine (SSME) to demonstrate their performance. © 1998 by the American Institute of Aeronautics and Astronautics. Inc. All rights reserved.

关键词： Space shuttles

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Motion Primitives for Stabilization and control of Underactuated Vehicles

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IFAC Proceedings Volumes 1998年第17期31卷 131-136页

作者： Francesco Bullo Naomi Ehrich Leonard Control and Dynamical Systems Mail Stop 107-81 California Institute of Technology Pasadena CA 91125 Department of Mechanical and Aerospace Engineering Princeton University Princeton NJ 08544

In this paper we construct motion primitives as algorithm building blocks for stabilization and control of a class of underactuated systems that includes spacecraft, submersibles and planar vehicles. The underactuated systems are modelled as Lagrangian systems on Lie groups; thus, they are systems with drift and with accessibility distributions described by the operation of Lie bracket and symmetric product. Directions of motion that are not directly actuated are identified with symmetric products of the input vector fields, and in-phase sinusoidal forcing is used in the primitives to generate motion in these directions. These primitives can then be used for a variety of low velocity maneuvers. For example, we demonstrate their use for exponential point stabilization and for static interpolation. We evaluate our algorithms and investigate the advantage of planning motions along relative equilibria.

关键词： underactuated systems mechanical systems exponential stabilization

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Robust failure detection for reentry vehicle attitude control systems

Robust failure detection for reentry vehicle attitude contro...

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Guidance, Navigation, and control Conference and Exhibit, 1998

作者： Agustin, Ramses M. Mangoubi, Rami S. Hain, Roger M. Adams, Neil J. M.I.T. Draper Laboratory Department of Mechanical Engineering 77 Massachusetts Ave. CambridgeMA02139 United States Control and Dynamical Systems Division C. S. Draper Laboratory 555 Tech Square CambridgeMA02139 United States

This paper presents a robust failure detection methodology for the attitude control system of Reusable Launch Vehicles (RLV). In particular, we consider the problem of estimating the thrust from multiple jets firing from the Reaction control System (RCS), as well as the related problem of distinguishing between failures in the RCS and the aerosurfaces. For accurately known vehicle and sensor models, the Kalman filter provides the optimal estimate for the jet thrust, in the least-squares sense. During reentry, however, plant model uncertainties are a major problem for the filter as the vehicle's aerodynamics vary widely with rapidly changing Mach number, making gain scheduling impractical. Consequently, the Kalman filter's performance degrades. Even if the Mach number were accurately known, rapid gain scheduling may not be desirable or even possible, due to the large data storage requirements it entails. Transient, robust H∞ or game-theoretic filters are designed for the space shuttle Orbiter's attitude determination system. Simulation results demonstrate that the robust filters can be insensitive to plant model uncertainties over a wide range of Mach numbers, while remaining sensitive to failures in the aerosurfaces and the RCS jets. © 1998, American Institute of Aeronautics and Astronautics, Inc.

关键词： Uncertainty analysis

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control of spatially varying distributed systems

Control of spatially varying distributed systems

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IEEE Conference on Decision and control

作者： G.E. Dullerud R. D'Andrea S.G. Lall Department of Mechanical and Industrial Engineering University of Illinois Urbana IL USA Department of Mechanical and Aerospace Engineering Cornell University Ithaca NY USA Department of Control and Dynamical Systems California Institute of Technology Pasadena CA USA

Considers control design for distributed systems, where the controller is to adopt and preserve the spatial structure of the system. Specifically systems that vary spatially are considered; namely those that are not shift invariant with respect to spatial variables. Operator theoretic tools for working with these systems are developed, and lead to convex conditions for analysis and synthesis with respect to the /spl Lscr//sub 2/-induced norm.

关键词： control systems Difference equations control system synthesis Integral equations Time varying systems Frequency domain analysis Hilbert space Industrial engineering Aerospace engineering control design

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Motion control for underactuated mechanical systems on Lie groups 4

Motion control for underactuated mechanical systems on Lie g...

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4th European control Conference, ECC 1997

作者： Bullo, Francesco Leonard, Naomi Ehrich Control and Dynamical Systems California Institute of Technology PasadenaCA91125 United States Dept. of Mechanical and Aerospace Engineering Princeton University PrincetonNJ08544 United States

ISBN: (纸本)9783952426906

control design for underactuated mechanical systems is an active area of research. In this paper we focus on mechanical control systems defined on Lie groups with the Lagrangian equal to kinetic energy. Examples include satellites and underwater vehicles. Under a controllability assumption, we propose two algorithms to compute small amplitude, periodic inputs that achieve arbitrary reconfigurations.

关键词： Lie groups

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Failure detection and isolation for the space shuttle main engine 33rd

Failure detection and isolation for the space shuttle main e...

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33rd Joint Propulsion Conference and Exhibit, 1997

作者： Ho, Nhut Lozano, Paulo Mangoubi, Rami Martinez-Sanchez, Manuel Department of Mechanical Engineering M.I.T. and Control and Dynamical Systems Division C. S. Draper Laboratory CambridgeMA02139 United States Department of Aeronautics and Astronautics Massachusetts Institute of Technology CambridgeMA02139 United States Control and Dynamical Systems Division C. S. Draper Laboratory CambridgeMA02139 United States

The Generalized Likelihood Ratio Test (GLRT) for Failure Detection and Isolation (FDI) is designed for the space shuttle main engine (SSME). The algorithm uses the entire thirty-seven state model of the SSME, as well as a set of fifteen sensors. It can be used for online FDI, as well for postfiight analysis. At the design stage, it can help determine the detectablility and distinguishability of failures, given a sensor configuration. Emphasis in the paper is on input/output failures, i.e., failures in the valves and sensors, but the likelihood ratio approach can be extended to include structural failures. © 1997, American Institute of Aeronautics and Astronautics, Inc.

关键词： Engines

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Stabilization of mechanical systems using controlled Lagrangians

Stabilization of mechanical systems using controlled Lagrang...

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IEEE Conference on Decision and control

作者： A.M. Bloch N.E. Leonard J.E. Marsden Department of Mathematics University of Michigan Ann Arbor MI USA Department of Mechanical and AeroSpace Engineering Princeton University Princeton NJ USA Control and Dynamical Systems California Institute of Technology Pasadena CA USA

We propose an algorithmic approach to stabilization of Lagrangian systems. The first step involves making admissible modifications to the Lagrangian for the uncontrolled system, thereby constructing what we call the controlled Lagrangian. The Euler-Lagrange equations derived from the controlled Lagrangian describe the closed-loop system where new terms are identified with control forces. Since the controlled system is Lagrangian by construction, energy methods can be used to find control gains that yield closed-loop stability. The procedure is demonstrated for the problem of stabilization of an inverted pendulum on a cart and for the problem of stabilization of rotation of a rigid spacecraft about its unstable intermediate axis using a single internal rotor. Similar results hold for the dynamics of an underwater vehicle.

关键词： mechanical systems control systems Lagrangian functions Force control Vehicle dynamics Stability Space vehicles Aerodynamics Equations Switches

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Erratum: ‘‘Interaction of adjacent bursts in the wall region’’ [Phys. Fluids 6, 954 (1994)]

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Physics of Fluids 1997年第1期9卷 247-247页

作者： B. D. Coller P. Holmes John Lumley Control and Dynamical Systems California Institute of Technology 104‐44 Pasadena California 91125 Department of Mechanical and Aerospace Engineering and Program in Applied and Computational Mathematics Princeton University Princeton New Jersey 08544 Sibley School of Mechanical and Aerospace Engineering Cornell University Ithaca New York 14853

B. D. Coller, P. Holmes, John Lumley; Erratum: ‘‘Interaction of adjacent bursts in the wall region’’ [Phys. Fluids 6, 954 (1994)], Physics of Fluids, Volume 9,

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Inexpensive electronic water level recorders for hydrologic studies

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GROUND WATER MONITORING AND REMEDIATION 1996年第2期16卷 77-83页

作者： Keenan, R Dickerson, J Gardner, L Reeves, H Richard Keenan is a hydrogeologist at Golder Associates Inc. Jacksonville Florida working on site investigation and remediation projects for ground water and soil contamination. His research interests include ground water modeling geologic analysis of coastal plain depositional environments and processing and analysis of remotely sensed images. He was raised in South Carolina and Puerto Rico and received a B.S. in marine science (1989) and an M.S. in geology (1994) from the University of South Carolina. John Dickerson has been on the civil engineering faculty of the University of South Carolina in Columbia South Carolina for the past 20 years. He is a registered professional engineer and specializes in dynamical measurements and control in addition to the application of microprocessors in engineering experiments. He grew up in northern Illinois received a mechanical engineering degree from the Illinois Institute of Technology in 1963 and a Ph.D. in applied mechanics from the California Institute of Technology in 1967. Leonard Gardner has been a faculty member of the Geological Sciences Department at the University of South Carolina in Columbia South Carolina since 1968. He has published numerous papers on the geochemistry of weathering and soil genesis and on geological and geochemical processes in salt marshes. He was born and raised in New Jersey received a B.S. in English (1958) from St. Peter's College in Jersey City and then earned a B.S. (1963) M.S. (1966) and Ph.D. (1968) in geology from the Pennsylvania State University. Howard W. Reeves is an assistant professor in Civil Engineering at Northwestern University. Reeves joined the faculty at Northwestern in 1994 to coordinate the environmental geotechnics research area and was an assistant professor of Geological Sciences at the University of South Carolina from 1991 to 1994. Reeves earned a B.S. in chemical engineering and an M.S. in environmental engineering at the University of Notre Dame and a Ph. D. in en vironmental engineering at The Un

Hydrologic investigations typically involve the collection of water level measurements at discrete points in space and time. The high cost of commercial electronic recorders can be a burden. We have developed an inexpensive ((similar to)$200) electronic water level recorder consisting of a Motorola microcontroller, a clock. memory, pressure transducers, and associated circuitry. The instrument is powered by a 6-V battery. These devices. each capable of monitoring up to eight channels of analog input, are presently providing continuous monitoring of nested piezometers, tide gauges, and rain gauges in hydrologic studies at the Savannah River site and the North Inlet (South Carolina) Long-Term Ecological Research (LTER) site. The instruments can be custom tailored to record water levels at any specified time interval, or whenever the water level changes by a specified amount, and can store up to 32,000 water level observations. These instruments have been used to conduct slug tests and can be configured to monitor observation wells for pumping tests. Simplicity of construction and availability of components offer hydrologists an inexpensive but reliable method of water level recording. Several examples of the use of this instrumentation in diverse hydrologic settings are described.

关键词： Recording instruments

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A bound on the number of integrators needed to linearize a control system

A bound on the number of integrators needed to linearize a c...

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IEEE Conference on Decision and control

作者： W.M. Sluis D.M. Tilbury Control and Dynamical Systems California Institute of Technology Pasadena CA USA Mechanical Engineering and Applied Mechanics University of Michigan Ann Arbor MI USA

For nonlinear control systems, the authors consider the problem of dynamic feedback linearization. In particular, for a restricted class of dynamic compensators that correspond to adding chains of integrators to the inputs, the authors give an upper bound for the order of the compensator that needs to be considered. Moreover, in the case of 2-input systems, it is shown that this bound is sharp.

关键词： control systems State feedback Linear feedback control systems Nonlinear control systems Nonlinear dynamical systems Linear systems Upper bound Nonlinear systems mechanical engineering Sufficient conditions

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