Attitude tracking with adaptive rejection of rate gyro disturbances

Abstract

Abstract-The classical attitude control problem for a rigid body is revisited under the assumption that measurements of the angular rates obtained by means of rate gyros are corrupted by harmonic disturbances, a setup of importance in several aerospace applications. The paper extends previous methods developed to compensate bias in angular rate measurements by accounting for a more general class of disturbances, and by allowing uncertainty in the inertial parameters. By resorting to adaptive observers designed on the basis of the internal model principle, it is shown how converging estimates of the angular velocity can be obtained, and used effectively in a passivity-based certainty-equivalence controller yielding global convergence within the chosen parametrization of the group of rotations. Since a persistence of excitation condition is not required for the convergence of the state estimates, only an upper bound on the number of distinct harmonic components of the disturbance is needed for the applicability of the method. I. PROBLEM DEFINITIONConsider the rotational dynamics of a rigid bodẏwith state (R, ω) ∈ SO(3) × R 3 , representing the orientation and angular velocity of a body-fixed frame with respect to an inertial frame, and control input u ∈ R 3 . The matrix S(·) denotes the skew-symmetric operator S(v)w := v×w, where v, w ∈ R 3 . The inertia matrix J(µ) ∈ R 3×3 is assumed to depend continuously on a vector of unknown parameters µ ranging over a given compact setfor the orientation and angular velocity of the body-fixed frame of (1) is provided by a smooth autonomous system of the form̟with state of importance in aerospace applications [1], and greatly simplify the analysis. The rotation matrix for the attitude error R e := R T d R ∈ SO(3) satisfies the kinematic equatioṅ R e = R e S(ω e ), where ω e := ω−R e T ω d denotes the angular velocity error resolved in the body frame.The classic attitude control problem [2] is loosely defined as that of finding a feedback control law such that all trajectories of the closed-loop system are bounded, and the tracking error satisfies (R e (t), ω e (t)) → (I 3 , 0) as t → ∞, for any given reference trajectory in the considered family of solutions of (2), and for all µ ∈ K µ . In this paper, the problem in question is revisited under the assumption that measurements of the rotation matrix R(t) are available, while measurements of ω(t) obtained by means of rate gyros are corrupted by additive harmonic noise. The considered setup arises frequently in the control of aerospace vehicles with significant aeroelastic effects [3], where structural vibrations are transmitted to the rate gyros through the coupling with the airframe, or in the attitude control of rigid of flexible satellites, where harmonic disturbance in the angular velocity measurements are produced by imbalance or mechanical defects in gyroscopes [4]- [6]. Dealing with uncertainties on the natural frequencies is a fundamental issue in applications to control of hypersonic vehicles, where the vibrational mo...

Finite‐time attitude control for rigid spacecraft‐based on adaptive super‐twisting algorithm

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Attitude tracking of rigid spacecraft based on extended state observer

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Design of Active PWM Control Driver Circuit for Torquer System Using CCII

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