Results 1  10
of
10
A Decentralized Approach to Formation Maneuvers
 IEEE Transactions on Robotics and Automation
, 2003
"... Abstract—This paper presents a behaviorbased approach to formation maneuvers for groups of mobile robots. Complex formation maneuvers are decomposed into a sequence of maneuvers between formation patterns. The paper presents three formation control strategies. The first strategy uses relative posit ..."
Abstract

Cited by 62 (0 self)
 Add to MetaCart
Abstract—This paper presents a behaviorbased approach to formation maneuvers for groups of mobile robots. Complex formation maneuvers are decomposed into a sequence of maneuvers between formation patterns. The paper presents three formation control strategies. The first strategy uses relative position information configured in a bidirectional ring topology to maintain the formation. The second strategy injects interrobot damping via passivity techniques. The third strategy accounts for actuator saturation. Hardware results demonstrate the effectiveness of the proposed control strategies. Index Terms—Behavioral methods, coordinated control, formations, mobile robots, passivity.
A Decentralized Approach To Elementary Formation Maneuvers
"... This paper presents the coupled dynamics approach to executing Elementary Formation Maneuvers (EFM) for Hilaretype mobile robots. The concept of an EFM is presented. It is then shown that each of these EFMs posses a common mathematical structure and thus may be executed by the same type of robot co ..."
Abstract

Cited by 35 (4 self)
 Add to MetaCart
This paper presents the coupled dynamics approach to executing Elementary Formation Maneuvers (EFM) for Hilaretype mobile robots. The concept of an EFM is presented. It is then shown that each of these EFMs posses a common mathematical structure and thus may be executed by the same type of robot control. We present three different EFM controls in this paper. The first puts feedback on the relative motion and the global motion of each robot. The second control adds interrobot damping. And the third control uses saturated inputs on the relative motion and the global motion of each robot. We present simulation and hardware results for each of these controls. I. Introduction Cooperative robots can often be used to perform tasks that are too difficult for a single robot to perform alone. For example a group of robots can be used for moving large awkward objects [1], [2] or for moving a large number of objects [3]. In addition groups of robots can be used for terrain model acquisition [3]...
Digital Passive Attitude and Altitude Control Schemes for Quadrotor Aircraft
 7th International Conference on Control and Automation
, 2009
"... This paper presents a formal method to design a digital inertial control system for quadrotor aircraft. In particular, it formalizes how to use approximate passive models in order to justify the initial design of passive controllers. Fundamental limits are discussed with this approach in particular ..."
Abstract

Cited by 13 (11 self)
 Add to MetaCart
This paper presents a formal method to design a digital inertial control system for quadrotor aircraft. In particular, it formalizes how to use approximate passive models in order to justify the initial design of passive controllers. Fundamental limits are discussed with this approach in particular how it relates to the control of systems consisting of cascades of three or more integrators in which input actuator saturation is present. Ultimately, two linear proportional derivative (PD) passive controllers are proposed to be combined with a nonlinear saturation element. It is also shown that yaw control can be performed independently of the inertial controller, providing a great deal of maneuverability for quadrotor aircraft. A corollary, based on the sector stability theorem provided by Zames and later generalized for the multipleinputoutput case by Willems, states the allowable range of k for the linear negative feedback controller kI in which the dynamic system H1: x1 → y1 is inside the sector [a1, b1], in which − ∞ < a1, 0 < b1 ≤ ∞, and b1> a1. This corollary provides a formal method to verify stability, both in simulation and in operation for a given family of inertial setpoints given to the quadrotor inertial controller. The controller is verified to perform exceptionally well when applied to a detailed model of the STARMAC, which includes blade flapping dynamics. I.
A QuaternionBased Adaptive Attitude Tracking Controller Without Velocity Measurements
 In proc. of the 39th IEEE CDC
, 2000
"... : The main problem addressed in this paper is the quaternionbased, attitude tracking control of rigid spacecraft without angular velocity measurements and in the presence of an unknown inertia matrix. As a steppingstone, we rst design an adaptive, fullstate feedback controller that compensates fo ..."
Abstract

Cited by 9 (2 self)
 Add to MetaCart
: The main problem addressed in this paper is the quaternionbased, attitude tracking control of rigid spacecraft without angular velocity measurements and in the presence of an unknown inertia matrix. As a steppingstone, we rst design an adaptive, fullstate feedback controller that compensates for parametric uncertainty while ensuring asymptotic attitude tracking errors. The adaptive, fullstate feedback controller is then redesigned such that the need for angular velocity measurements is eliminated. The proposed adaptive, output feedback controller ensures asymptotic attitude tracking. 1 Introduction The attitude control of rigid bodies has important applications ranging from rigid aircraft and spacecraft systems to coordinated robot manipulators (see [18] for a literature review of the many di#erent types of applications). For example, rigid spacecraft applications in particular (e.g., satellite surveillance and communication) often have need of highly accurate slewing and/or poi...
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 ..."
Abstract

Cited by 5 (1 self)
 Add to MetaCart
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...
A BehaviorBased Approach to Multiple Spacecraft Formation Flying
, 2000
"... of a dissertation submitted by Jonathan R. T. Lawton This dissertation has been read by each member of the following graduate committee and by majority vote has been found to be satisfactory. ..."
Abstract

Cited by 4 (1 self)
 Add to MetaCart
of a dissertation submitted by Jonathan R. T. Lawton This dissertation has been read by each member of the following graduate committee and by majority vote has been found to be satisfactory.
Laplacian cooperative attitude control of multiple rigid bodies
 in Proceedings of the IEEE International Symposium on Intelligent Control
, 2006
"... Abstract — Motivated by the fact that linear controllers can stabilize the rotational motion of a rigid body, we propose in this paper a control strategy that exploits graph theoretic tools for cooperative control of multiple rigid bodies. The control objective is to stabilize the system to a config ..."
Abstract

Cited by 2 (0 self)
 Add to MetaCart
Abstract — Motivated by the fact that linear controllers can stabilize the rotational motion of a rigid body, we propose in this paper a control strategy that exploits graph theoretic tools for cooperative control of multiple rigid bodies. The control objective is to stabilize the system to a configuration where the rigid bodies will have a common orientation and common angular velocity. The control law respects the limited information each rigid body has with respect to the rest of the team. Specifically, each rigid body is equipped with a control law that is based on the Laplacian matrix of the communication graph, which encodes the limited communication capabilities between the team members. Similarly to the linear case, the convergence of the multiagent system relies on the connectivity of the communication graph. I.
Distributed Attitude Synchronization for Multiple Rigid Bodies with EulerLagrange Equations of Motion
"... Abstract — In this paper, distributed attitude synchronization problems are considered for multiple rigid bodies with attitude dynamics represented by EulerLagrange equations of motion. Three distributed control laws for attitude synchronization are proposed and analyzed. The first control law intr ..."
Abstract

Cited by 1 (0 self)
 Add to MetaCart
Abstract — In this paper, distributed attitude synchronization problems are considered for multiple rigid bodies with attitude dynamics represented by EulerLagrange equations of motion. Three distributed control laws for attitude synchronization are proposed and analyzed. The first control law introduces bounded functions to reduce the required control torque. The second control law applies a passivity approach to remove the requirement for relative angular velocity measurement between neighboring rigid bodies. The third control law incorporates a timevarying reference attitude, where the reference attitude is allowed to be available to only a subset of the group members. It is shown that the first two control laws guarantee distributed attitude synchronization under any undirected connected communication topology. The third control law guarantees that all rigid bodies track the timevarying reference attitude as long as a virtual node whose state is the timevarying reference attitude has a directed path to all of the rigid bodies in the group. Simulation results are presented to demonstrate the effectiveness of the three control laws. I.
1 A Digital Control Architecture for Quadrotor Aircraft
"... Abstract — We show that the principal attitude and inertial dynamics of a quadrotor aircraft can be decomposed into a cascade of three passive and one interior conic subsystem such that a proportional digital feedback loop can effectively be applied to each subsystem in a nested manner. This proport ..."
Abstract
 Add to MetaCart
Abstract — We show that the principal attitude and inertial dynamics of a quadrotor aircraft can be decomposed into a cascade of three passive and one interior conic subsystem such that a proportional digital feedback loop can effectively be applied to each subsystem in a nested manner. This proportional feedback architecture includes one saturation block nested between the attitude and inertial control systems to account for actuator saturation. Our architecture can control yaw independently of the desired inertial position. Stability of this architecture can be verified in both simulation and runtime through the following corollary derived from the sector stability theorem of Zames and later Willems. The corollary applies to the control of a dynamic system H1: x1 → y1 which is inside the sector [a1,b1], in which − ∞ < a1 < 0, 0 < b1 ≤ ∞, and b1> a1. It states that if a negative feedback controller with reference r1 and control gain k1 < − 1 a1 is applied to H1: x1 → y1 such that x1 = k1(r1 −y1) then the closed loop system Hcl−1: r1 → y1 is L m 2 (l m 2) stable. Simulations indicate the controller performs exceptionally well when applied to detailed STARMAC and Hummingbird aircraft models which includes blade flapping effects. I.
SPACECRAFT NONLINEAR ATTITUDE CONTROL WITH BOUNDED CONTROL INPUT
, 2009
"... A copy can be downloaded for personal noncommercial research or study, without prior permission or charge This thesis cannot be reproduced or quoted extensively from without first obtaining permission in writing from the Author The content must not be changed in any way or sold commercially in any ..."
Abstract
 Add to MetaCart
A copy can be downloaded for personal noncommercial research or study, without prior permission or charge This thesis cannot be reproduced or quoted extensively from without first obtaining permission in writing from the Author The content must not be changed in any way or sold commercially in any format or medium without the formal permission of the Author When referring to this work, full bibliographic details including the author, title, awarding institution and date of the thesis must be given.