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68
Design and Control of an Indoor Micro Quadrotor
 IN PROC. OF INT. CONF. ON ROBOTICS AND AUTOMATION
, 2004
"... Recent progress in sensor technology, data processing and integrated actuators has made the development of miniature flying robots fully possible. Micro VTOL systems represent a useful class of flying robots because of their strong capabilities for smallarea monitoring and building exploration. In ..."
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Cited by 70 (5 self)
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Recent progress in sensor technology, data processing and integrated actuators has made the development of miniature flying robots fully possible. Micro VTOL systems represent a useful class of flying robots because of their strong capabilities for smallarea monitoring and building exploration. In this paper we describe the approach that our lab has taken to micro VTOL evolving towards full autonomy, and present the mechanical design, dynamic modelling, sensing, and control of our indoor VTOL autonomous robot OS4.
Backstepping and Slidingmode Techniques Applied to an Indoor Micro Quadrotor
 In Proceedings of IEEE Int. Conf. on Robotics and Automation
, 2005
"... Abstract — The latest technological progress in sensors, actuators and energy storage devices enables the developments of miniature VTOL 1 systems. In this paper we present the results of two nonlinear control techniques applied to an autonomous micro helicopter called Quadrotor. A backstepping and ..."
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Cited by 63 (5 self)
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Abstract — The latest technological progress in sensors, actuators and energy storage devices enables the developments of miniature VTOL 1 systems. In this paper we present the results of two nonlinear control techniques applied to an autonomous micro helicopter called Quadrotor. A backstepping and a slidingmode techniques. We performed various simulations in open and closed loop and implemented several experiments on the testbench to validate the control laws. Finally, we discuss the results of each approach. These developments are part of the OS4 2 project in our lab.
Cascade Normal Forms for Underactuated Mechanical Systems
 Proc. of the 39th Conf. on Decision and Control
, 2000
"... In this paper, we introduce cascade normal forms for underactuated mechanical systems that are convenient for control design. These normal forms are partially linear which results from a wellknown fact that underactuated systems can be partially linearized using a change of control [12]. The diffic ..."
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Cited by 27 (3 self)
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In this paper, we introduce cascade normal forms for underactuated mechanical systems that are convenient for control design. These normal forms are partially linear which results from a wellknown fact that underactuated systems can be partially linearized using a change of control [12]. The difficulty arises when the new control appears both in the linear and nonlinear subsystems. We introduce a method for decoupling these two subsystems by applying a change of coordinates that transforms the dynamics of the system into a cascade normal form with the property that control of the overall system reduces to control of its nonlinear subsystem. Under a symmetry condition on the inertia matrix of the system, this transformation can be obtained explicitly from the Lagrangian. This eventually leads to classification of underactuated systems. We provide several applications and two detailed examples of complex underactuated systems, namely, the Acrobot and the Rotating Pendulum.
Nonlinear control of mechanical systems with one degree of underactuation
 IN PROC. OF THE IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION
, 2004
"... Numerous robotic tasks associated with underactuation have been studied in the literature. For a large number of these in the plane, the mechanical models have a cyclic variable, the cyclic variable is unactuated, and all shape variables are independently actuated. This paper formulates and solves ..."
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Cited by 25 (5 self)
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Numerous robotic tasks associated with underactuation have been studied in the literature. For a large number of these in the plane, the mechanical models have a cyclic variable, the cyclic variable is unactuated, and all shape variables are independently actuated. This paper formulates and solves two control problems for this class of models. If the generalized momentum conjugate to the cyclic variable is not conserved, conditions are found for the existence of a set of outputs that yields a system with a onedimensional exponentially stable zero dynamics — i.e. an exponentially minimumphase system — along with a dynamic extension that renders the system locally inputoutput decouplable. If the generalized momentum conjugate to the cyclic variable is conserved, a reduced system is constructed and conditions are found for the existence of a set of outputs that yields an empty zero dynamics, along with a dynamic extension that renders the system feedback linearizable. A common element in these two feedback problems is the construction of a scalar function of the configuration variables that has relative degree three with respect to one of the input components. The function arises by partially integrating the conjugate momentum. The results are illustrated on two balancing tasks and on a ballistic flip motion.
Distributed Structural Stabilization and Tracking for Formations of Dynamic MultiAgents
 Tech. Rep. CITCDS 2002002, California Institute of Technology, Control and Dynamical Systems
, 2002
"... In this paper, we provide a theoretical framework that consists of graph theoretical and Lyapunovbased approaches to stability analysis and distributed control of multiagent formations. This framework relays on the notion of graph rigidity as a means of identifying the shape variables of a formati ..."
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Cited by 23 (0 self)
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In this paper, we provide a theoretical framework that consists of graph theoretical and Lyapunovbased approaches to stability analysis and distributed control of multiagent formations. This framework relays on the notion of graph rigidity as a means of identifying the shape variables of a formation. Using this approach, we can formally de ne formations of multiple vehicles and three types of stabilization/tracking problems for dynamic multiagent systems. We show how these three problems can be addressed mutually independent of each other for a formation of two agents. Then, we introduce a procedure called dynamic node augmentation that allows construction of a larger formation with more agents that can be rendered structurally stable in a distributed manner from some initial formation that is structurally stable. We provide two examples of formations that can be controlled using this approach, namely, the V formation and the diamond formation.
Global Configuration Stabilization for the VTOL Aircraft with Strong Input Coupling
, 2002
"... Trajectory tracking and con guration stabilization for the VTOL aircraft (vertical take o and landing) has been so far considered in the literature only in the presence of a slight (or zero) input coupling (i.e. for a small ). In this paper, our main contribution is to address global con guration ..."
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Cited by 17 (2 self)
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Trajectory tracking and con guration stabilization for the VTOL aircraft (vertical take o and landing) has been so far considered in the literature only in the presence of a slight (or zero) input coupling (i.e. for a small ). In this paper, our main contribution is to address global con guration stabilization for the VTOL aircraft with a strong input coupling using a smooth static state feedback. In addition, the dierentially at outputs for the VTOL aircraft are automatically obtained as a byproduct of applying a decoupling change of coordinates.
Robust Adaptive Path Following of Underactuated Ships
 Automatica, V
, 2002
"... ABSTRACT: Robust path following is an issue of vital practical importance to the ship industry. In this paper, a nonlinear robust adaptive control strategy is developed to force an underactuated surface ship to follow a predefined path at a desired speed, despite the presence of environmental distur ..."
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Cited by 14 (0 self)
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ABSTRACT: Robust path following is an issue of vital practical importance to the ship industry. In this paper, a nonlinear robust adaptive control strategy is developed to force an underactuated surface ship to follow a predefined path at a desired speed, despite the presence of environmental disturbances induced by wave, wind and oceancurrent. The proposed controller is scalable and is designed using Lyapunov's Direct Method and the popular backstepping and parameter projection techniques. Along the way of proving closedloop stability, we obtain a new stability result for nonlinear cascade systems with nonvanishing uncertainties. Interestingly, it is shown in this paper that our developed control strategy is easily extendible to situations of practical importance such as parking and pointtopoint navigation. 1.
Nonlinear Model Reduction and Decentralized Control of Tethered Formation Flight
 Journal of Guidance, Control, and Dynamics
"... This paper describes a fully decentralized nonlinear control law for spinning tethered formation flight, based on exploiting geometric symmetries to reduce the original nonlinear dynamics into simpler stable dynamics. Motivated by oscillation synchronization inbiological systems,weuse contraction th ..."
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Cited by 9 (9 self)
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This paper describes a fully decentralized nonlinear control law for spinning tethered formation flight, based on exploiting geometric symmetries to reduce the original nonlinear dynamics into simpler stable dynamics. Motivated by oscillation synchronization inbiological systems,weuse contraction theory to prove that a control law stabilizing a singletethered spacecraft can also stabilize arbitrary large circular arrays of spacecraft, as well as the three inline configuration. The convergence result is global and exponential. Numerical simulations and experimental results using the SPHERES testbed validate the exponential stability of the tethered formation arrays by implementing a tracking control law derived from the reduced dynamics. I.
STABLE SYNCHRONIZATION OF RIGID BODY NETWORKS
, 2007
"... We address stable synchronization of a network of rotating and translating rigid bodies in threedimensional space. Motivated by applications that require coordinated spinning spacecraft or diving underwater vehicles, we prove control laws that stably couple and coordinate the dynamics of multiple ..."
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Cited by 9 (2 self)
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We address stable synchronization of a network of rotating and translating rigid bodies in threedimensional space. Motivated by applications that require coordinated spinning spacecraft or diving underwater vehicles, we prove control laws that stably couple and coordinate the dynamics of multiple rigid bodies. We design decentralized, energy shaping control laws for each individual rigid body that depend on the relative orientation and relative position of its neighbors. Energy methods are used to prove stability of the coordinated multibody dynamical system. To prove exponential stability, we break symmetry and consider a controlled dissipation term that requires each individual to measure its own velocity. The control laws are illustrated in simulation for a network of spinning rigid bodies.
Introduction to Feedback Control of Underactuated VTOL Vehicles
"... The paper is an introduction to feedback control design for a family of robotic aerial vehicles with Vertical Take ..."
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Cited by 8 (2 self)
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The paper is an introduction to feedback control design for a family of robotic aerial vehicles with Vertical Take