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Hybrid Attitude Control and Estimation on SO(3) Western University Scholarship@Western Electronic Thesis and Dissertation Repository 11-29-2017 4:00 PM Hybrid Attitude Control and Estimation On SO(3) Soulaimane Berkane The University of Western Ontario Supervisor Tayebi, Abdelhamid The University of Western Ontario Graduate Program in Electrical and Computer Engineering A thesis submitted in partial fulfillment of the equirr ements for the degree in Doctor of Philosophy © Soulaimane Berkane 2017 Follow this and additional works at: https://ir.lib.uwo.ca/etd Part of the Acoustics, Dynamics, and Controls Commons, Controls and Control Theory Commons, and the Navigation, Guidance, Control and Dynamics Commons Recommended Citation Berkane, Soulaimane, "Hybrid Attitude Control and Estimation On SO(3)" (2017). Electronic Thesis and Dissertation Repository. 5083. https://ir.lib.uwo.ca/etd/5083 This Dissertation/Thesis is brought to you for free and open access by Scholarship@Western. It has been accepted for inclusion in Electronic Thesis and Dissertation Repository by an authorized administrator of Scholarship@Western. For more information, please contact [email protected]. Abstract This thesis presents a general framework for hybrid attitude control and estimation de- sign on the Special Orthogonal group SO(3). First, the attitude stabilization problem on SO(3) is considered. It is shown that, using a min-switch hybrid control strategy de- signed from a family of potential functions on SO(3), global exponential stabilization on SO(3) can be achieved when this family of potential functions satisfies certain properties. Then, a systematic methodology to construct these potential functions is developed. The proposed hybrid control technique is applied to the attitude tracking problem for rigid body systems. A smoothing mechanism is proposed to filter out the discrete behaviour of the hybrid switching mechanism leading to control torques that are continuous. Next, the problem of attitude estimation from continuous body-frame vector mea- surements of known inertial directions is considered. Two hybrid attitude and gyro bias observers designed directly on SO(3) × R3 are proposed. The first observer uses a set of innovation terms and a switching mechanism that selects the appropriate innovation term. The second observer uses a fixed innovation term and allows the attitude state to be reset (experience discrete transition or jump) to an adequately chosen value on SO(3). Both hybrid observers guarantee global exponential stability of the zero estimation errors. Finally, in the case where the body-frame vector measurements are intermittent, an event-triggered attitude estimation scheme on SO(3) is proposed. The observer consists in integrating the continuous angular velocity during the interval of time where the vector measurements are not available, and updating the attitude state upon the arrival of the vector measurements. Both cases of synchronous and asynchronous vector measurements with possible irregular sampling periods are considered. Moreover, some modifications to the intermittent observer are developed to handle different practical issues such as discrete-time implementation, noise filtering and gyro bias compensation. ii To all those whom I love... iii Acknowledgement I would like to express my deepest gratitude to my advisor, Professor Abdelhamid Tayebi, for his support, motivation and guidance throughout the four years I have spent at Western University. He taught me what it meant to be a high quality researcher who carries fundamental values such as honesty, vision, passion and rigorousness. His timely feedback and suggestions helped me to smoothly conduct my research and write my thesis. I am grateful to my friend, colleague and collaborator, Dr. Abdelkader Abdessameud, with whom I have completed several parts of this research and shared countless discus- sions in the research field. I am also thankful to my alternate supervisor at Western, Dr. Ilia Polushin, who have helped me in several occasions. I would also like to sincerely thank Prof. Jin Jiang and Dr. Lyndon Brown for taking the time to serve as my PhD thesis examiners and for their constructive comments and feedback. I would especially like to thank Prof. Andrew R. Teel from the University of California Santa Barbara for agreeing to review and examine my thesis. I have had several fruitful discussions with him during our meetings at CDC and ACC conferences. Lastly, I would like to extend my sincere appreciation to my family. To my mother, Chahrazed, my sisters and my friends for their support and prayers in all my pursuits. And of course, to my wife, Intissar, for her love, support and understanding. iv List of Symbols • N and N>0 denote the natural and strictly positive natural numbers, respectively. • R, R≥0 and R>0 denote the real, nonnegative and positive real numbers, respec- tively. • Rn is the n-dimensional Euclidean space . • Rn×m is the set of real-valued n × m matrices. • Given A 2 Rn×m, A> denotes its transpose. • Given A 2 Rn×n, det(A) denotes its determinant. • Given A 2 Rn×n, tr(A) denotes the sum of its diagonal entries (trace). • Given A; B 2 Rn×m, their Euclidean inner product is defined as hhA; Bii = tr(A>B). n×m p • Given A 2 R , its Frobenius norm is kAkF = hhA; Aii. p • Given x 2 Rn, its Euclidean norm (2-norm) is given by kxk = x>x. • Sn = fx 2 Rn+1 : kxk = 1g is the unit n-sphere embedded in Rn+1. • B = fx 2 Rn : kxk ≤ 1g is the closed unit ball in Euclidean space. • SO(3) = fR 2 R3×3 : det(R) = 1; RR> = R>R = Ig is the Special Orthogonal group of order 3 where I denotes the three-dimensional identity matrix. • so(3) = fΩ 2 R3×3 :Ω> = −Ωg is the set of all skew-symmetric 3 × 3 matrices and defines also the Lie algebra of SO(3). • Q = f(η; ) 2 R × R3 : η2 + > = 1g is the set of unit quaternions. p • Given a rotation matrix R 2 SO(3), let us define jRjI = kI − Rk= 8. 3×3 3×3 1 > • The map E : R ! R is defined as E(M) = 2 (tr(M)I − M ). 2 • The map Ra : R × S ! SO(3) is defined as Ra(θ; u) = I + sin(θ)[u]× + (1 − 2 cos(θ))[u]×. 2 • The map Ru : Q ! SO(3) is defined as Ru(η; ) = I + 2[]× + 2η[]×. v 3 1 2 > • The map Rr : R ! SO(3) is defined as Rr(z) = 1+kzk2 (1 − kzk )I + 2zz + 2[z]× . 3×3 3×3 • The map PSO(3) : R ! SO(3) is defined as the projection of X 2 R on SO(3) (i.e. closest rotation matrix to X). 3×3 > • The map Pso(3) : R ! so(3) is defined as Pso(3)(M) = (M − M )=2. 3 3 • The map [·]× : R ! so(3) is defined as [x]×y = x × y for all x; y 2 R where × denotes the cross product on R3. 3 • The map vex : so(3) ! R is the inverse map of [·]×. 3×3 3 • The map : R ! R is defined as = vex ◦ Pso(3) where the symbol ◦ is used to denote function composition. • The set ΠSO(3) = fR 2 SO(3) : tr(R) 6= −1g is the set of all rotations with an angle ◦ 2 different than 180 . In other words, ΠSO(3) = SO(3) n Ra(π; S ). • The set ΠQ = f(η; ) 2 Q : η 6= 0g is the double cover of ΠSO(3) in Q. 3 3 3 • The map Pc : R × R ! R , for a given c 2 R≥0, defines the parameter projection function which is given in (2.3). • Given a set S, cl(S) denotes its closure (S together with all of its limit points). • A set-valued map F : M ⇒ N assigns to every x 2 M a set of values F(x) ⊆ N . • Let F : M ⇒ N be a set-valued function. The domain of F is defined as the set domF = fx 2 M : F(x) 6= ;g where ; denotes the empty set. • Cn(M; N ) is the set of all functions f : M!N such that the first n 2 N derivatives of each function f 2 Cn(M; N ) exist and are continuous. vi Contents Abstract ii Acknowlegements iv List of Symbols v List of Figures xi 1 Introduction 1 1.1 General Introduction . 1 1.2 Attitude Control . 2 1.3 Attitude Estimation . 5 1.4 Thesis Contributions . 7 1.5 List of Publications . 10 1.6 Thesis Outline . 12 2 Background and Preliminaries 14 2.1 General Notations . 14 2.2 Rigid Body Attitude . 16 2.2.1 Attitude Parametrizations . 18 2.2.1.1 Exponential Coordinates Representation . 18 2.2.1.2 Angle-Axis Representation . 19 2.2.1.3 Unit Quaternions Representation . 20 2.2.1.4 Rodrigues Vector Representation . 21 2.2.2 Metrics on SO(3) . 21 2.2.3 Attitude Visualization . 23 2.2.4 Useful Identities and Lemmas . 24 2.3 Hybrid Systems Framework . 28 2.3.1 Exponential Stability for Hybrid Systems . 30 2.4 Numerical Integration Tools . 32 vii 2.4.1 Numerical Integration on Rn ..................... 33 2.4.2 Numerical Integration on SO(3) . 34 2.4.3 Numerical Integration of Hybrid Systems . 35 3 Hybrid Attitude Control on SO(3) 37 3.1 Introduction . 37 3.2 Motivation Using Planar Rotations on S1 . 38 3.3 Attitude Stabilization on SO(3) . 47 3.3.1 Problem Formulation . 47 3.3.2 Smooth Attitude Stabilization on SO(3) . 48 3.3.3 Synergistic and Exp-Synergistic Potential Functions . 51 3.3.4 Hybrid Attitude Stabilization on SO(3) . 53 3.3.5 Construction of Exp-Synergistic Potential Functions . 55 3.3.6 Illustration of the Switching Mechanism . 64 3.4 Attitude Tracking for Rigid Body Systems .
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