Global exponential attitude tracking for spacecraft with gyro bias estimation

TL;DR

This paper develops a globally exponentially convergent attitude tracking controller for spacecraft that estimates gyro bias and enhances robustness and energy efficiency, using contraction analysis and hysteretic switching.

Contribution

It introduces a novel nonlinear observer for gyro bias estimation combined with a globally convergent attitude controller that is unwinding-free and robust to noise and bias.

Findings

The proposed controller achieves exponential convergence of attitude error.

Simulation results demonstrate improved robustness and energy efficiency.

The method effectively estimates gyro bias and maintains stability under noise.

Abstract

This paper addresses the global exponential attitude tracking of a spacecraft when gyro measurements are corrupted by bias. Based on contraction analysis, an exponentially convergent nonlinear observer is designed first to estimate the gyro bias. Relying on this bias estimator and the quaternion logarithm representation of the tracking error, an exponentially globally convergent controller is devised. This controller stabilizes the unique equilibrium of the closed-loop system, where the tracking error is the unit quaternion. For more energy-efficiency and enhancing the robustness in the presence of measurement noise, a hysteretically switching variable as in [1] is incorporated in the control loop and an unwinding-free globally exponentially convergent tracking controller is obtained. Numeric simulations were done to evaluate its performance in terms of tracking errors and energy-efficiency, as well as the robustness to measurement noise and time-varying bias in gyro sensors.