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27
Coordinated Target Assignment and Intercept for Unmanned Air Vehicles
, 2002
"... This paper presents an endtoend solution to the battlefield scenario where M unmanned air vehicles are assigned to strike N known targets, in the presence of dynamic threats. The problem is decomposed into the subproblems of (1) cooperative target assignment, (2) coordinated UAV intercept, (3) pat ..."
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Cited by 150 (15 self)
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This paper presents an endtoend solution to the battlefield scenario where M unmanned air vehicles are assigned to strike N known targets, in the presence of dynamic threats. The problem is decomposed into the subproblems of (1) cooperative target assignment, (2) coordinated UAV intercept, (3) path planning, and (4) feasible trajectory generation. The design technique is based on a hierarchical approach to coordinated control. Detailed simulation results are presented.
Online Control Customization via OptimizationBased Control
 In SoftwareEnabled Control: Information Technology for Dynamical Systems
, 2002
"... this paper show the success of this choice for V for stabilization. An innerloop PD controller on #, # is implemented to stabilize to the receding horizon states # # T , # # T . The # dynamics are the fastest for this system and although most receding horizon controllers were found to be nomi ..."
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Cited by 29 (13 self)
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this paper show the success of this choice for V for stabilization. An innerloop PD controller on #, # is implemented to stabilize to the receding horizon states # # T , # # T . The # dynamics are the fastest for this system and although most receding horizon controllers were found to be nominally stable without this innerloop controller, small disturbances could lead to instability
Nonlinear Control of Mechanical Systems: A Riemannian Geometry Approach
, 1998
"... Nonlinear control of mechanical systems is a challenging discipline that lies at the intersection between control theory and geometric mechanics. This thesis sheds new light on this interplay while investigating motion control problems for Lagrangian systems. Both stability and motion planning aspec ..."
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Cited by 29 (0 self)
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Nonlinear control of mechanical systems is a challenging discipline that lies at the intersection between control theory and geometric mechanics. This thesis sheds new light on this interplay while investigating motion control problems for Lagrangian systems. Both stability and motion planning aspects are treated within a unified framework that accounts for a large class of devices such as robotic manipulators, autonomous vehicles and locomotion systems. One distinguishing feature of mechanical systems is the number of control forces. For systems with as many input forces as degrees of freedom, many control problems are tractable. One contribution of this thesis is a set of trajectory tracking controllers designed via the notions of configuration and velocity error. The proposed approach includes as special cases a variety of results on joint and workspace control of manipulators as well as on attitude and position control of vehicles. Whenever fewer input forces are available than deg...
Nonlinear Control of Mechanical Systems: A Lagrangian Perspective
, 1997
"... . Recent advances in geometric mechanics, motivated in large part by applications in control theory, have introduced new tools for understanding and utilizing the structure present in mechanical systems. In particular, the use of geometric methods for analyzing Lagrangian systems with both symmetr ..."
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Cited by 26 (4 self)
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. Recent advances in geometric mechanics, motivated in large part by applications in control theory, have introduced new tools for understanding and utilizing the structure present in mechanical systems. In particular, the use of geometric methods for analyzing Lagrangian systems with both symmetries and nonintegrable (or nonholonomic) constraints has led to a unified formulation of the dynamics that has important implications for a wide class of mechanical control systems. This paper presents a survey of recent results in this area, focusing on the relationships between geometric phases, controllability, and curvature, and the role of trajectory generation in nonlinear controller synthesis. Examples are drawn from robotics and flight control systems, with an emphasis on motion control problems. Key Words. Geometric mechanics, nonlinear control, Lagrangian dynamics, motion control. 1. INTRODUCTION Mechanical systems form an important class of nonlinear control systems that h...
Flat systems, equivalence and trajectory generation
, 2003
"... Flat systems, an important subclass of nonlinear control systems introduced via differentialalgebraic methods, are defined in a differential geometric framework. We utilize the infinite dimensional geometry developed by Vinogradov and coworkers: a control system is a diffiety, or more precisely, an ..."
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Cited by 20 (4 self)
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Flat systems, an important subclass of nonlinear control systems introduced via differentialalgebraic methods, are defined in a differential geometric framework. We utilize the infinite dimensional geometry developed by Vinogradov and coworkers: a control system is a diffiety, or more precisely, an ordinary diffiety, i.e. a smooth infinitedimensional manifold equipped with a privileged vector field. After recalling the definition of aLieBäcklund mapping, we say that two systems are equivalent if they are related by a LieBäcklund isomorphism. Flat systems are those systems which are equivalent to a controllable linear one. The interest of such an abstract setting relies mainly on the fact that the above system equivalence is interpreted in terms of endogenous dynamic feedback. The presentation is as elementary as possible and illustrated by the VTOL aircraft.
Trajectory Generation for Kinematic Legged Robots, submitted
, 1997
"... Abstract. We present a general trajectory generation scheme for a class of “kinematic ” legged robots. The method does not depend upon the number of legs, nor is it based on foot placement concepts. Instead, our method is based on an extension of a nonlinear trajectory generation algorithm for smoo ..."
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Cited by 19 (8 self)
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Abstract. We present a general trajectory generation scheme for a class of “kinematic ” legged robots. The method does not depend upon the number of legs, nor is it based on foot placement concepts. Instead, our method is based on an extension of a nonlinear trajectory generation algorithm for smooth systems to the legged case, where the relevant mechanics are not smooth. Our extension is based on the realization that legged robot configuration spaces are stratified. The algorithm is illustrated with a simple example. 1
OffEquilibrium Linearisation And Design Of Gain Scheduled Control With Application To Vehicle Speed Control
, 1998
"... In conventional gain scheduled control design, linearisation of a timeinvariant nonlinear system and local control design for the resulting set of linear timeinvariant systems is performed at a set of equilibrium points. Due to its validity only near equilibrium, such a design may result in poor tr ..."
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Cited by 14 (9 self)
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In conventional gain scheduled control design, linearisation of a timeinvariant nonlinear system and local control design for the resulting set of linear timeinvariant systems is performed at a set of equilibrium points. Due to its validity only near equilibrium, such a design may result in poor transient performance. To resolve this problem one can base the control design on a dynamic linearisation about some nominal trajectory. However, a drawback with this approach is that control design for the resulting linear timevarying system is in general a difficult problem. In this paper it is suggested that linearisation and local controller design should be carried out not only at equilibrium states, but also in transient operating regimes. It is shown that this results in a set of timeinvariant linearisations which, when they are interpolated, form a close approximation to the timevarying system resulting from dynamic linearisation. Consequently, the transient performance can be imp...
Visual servoing of a UGV from a UAV using differential flatness
 In Proceedings of IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS 2003), Las Vegas, NV, USA, 27 October–1
, 2003
"... endorsement of any of the University of Pennsylvania's products or services. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution m ..."
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Cited by 12 (3 self)
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endorsement of any of the University of Pennsylvania's products or services. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to pubspermissions@ieee.org. By choosing to view this document, you agree to all provisions of the copyright laws protecting it.
Control Of Spacecraft Subject To Actuator Failures: StateOfTheArt And Open Problems
 Problems,” Proceedings of the R.H. Battin Astrodynamics Symposium, College Station, TX, March 2021, 2000, AAS Paper
"... this paper we review the main results in the area of active control of spacecraft with one actuator failure. We emphasize the qualitative characteristics that make this a challenging control problem. We present a series of new results that solve the problem of detumbling with simultaneous attitude s ..."
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Cited by 12 (1 self)
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this paper we review the main results in the area of active control of spacecraft with one actuator failure. We emphasize the qualitative characteristics that make this a challenging control problem. We present a series of new results that solve the problem of detumbling with simultaneous attitude stabilization about the unactuated axis, the complete attitude stabilization problem, and the feasible trajectory generation problem for a spacecraft with one actuator failure. We present several numerical examples that demonstrate the efficacy of the proposed control algorithms. We conclude with a brief review of some open problems in the general area of spacecraft control subject to actuator and/or sensor failures. INTRODUCTION Recent advances in spacecraft and satellite control systems have succeeded in solving several challenging problems dealing with the attitude tracking, robust control of rigid and flexible spacecraft, optimal slew maneuvers, precision pointing, formation flying, etc. Techniques from nonlinear [1, 2, 3, 4, 5, 6], adaptive [7, 8, 9, 10, 11, 12], optimal [13, 14, 15, 16, 17, 18, 19, 20, 21] and robust control [9, 22, 23, 24, 25] have been used to this end with a lot of success. Most (if not all) of these results assume that the spacecraft is actively controlled with a sufficient number of actuators equal to, or larger than, the degrees of freedom of the system. Although this is certainly the case # Associate Professor, School of Aerospace Engineering. Email: ########################. Senior member AIAA. + Graduate Student, School of Aerospace Engineering. Email: ######################### 1 with most current spacecraft, these control laws  by and large  do not account for unexpected actuator and/or sensor failures. It appears that the issue of sp...
Trajectory Generation for Nonlinear Control Systems
, 1997
"... This thesis explores the paradigm of two degree of freedom design for nonlinear control systems. In two degree of freedom design one generates an explicit trajectory for state and input around which the system is linearized. Linear techniques are then used to stabilize the system around the nominal ..."
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Cited by 8 (2 self)
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This thesis explores the paradigm of two degree of freedom design for nonlinear control systems. In two degree of freedom design one generates an explicit trajectory for state and input around which the system is linearized. Linear techniques are then used to stabilize the system around the nominal trajectory and to deal with uncertainty. This approach allows the use of the wealth of tools in linear control theory to stabilize a system in the face of uncertainty, while exploiting the nonlinearities to increase performance. Indeed, this thesis shows through simulations and experiments that the generation of a nominal trajectory allows more aggressive tracking in mechanical systems. The generation