Preassigned Performance Attitude Control Without Singularity and Unwinding Phenomenon

This article introduces a unified framework for quaternion-based preassigned performance control of aircraft attitude, effectively addressing the persistent challenges of unwinding phenomena and singularity issues. Within this framework, a performance function is first derived based on preassigned performance specifications. Subsequently, a model-based preset trajectory (PT) is synthesized to lie within the envelope of this function, designed to converge asymptotically to the origin while inherently possessing unwinding-free properties to guide states towards the nearest equilibrium point, thus eliminating unnecessary rotations. Following this, a prescribed-time controller is designed to strictly confine the attitude tracking error within a restricted tubular neighborhood surrounding the PT, guaranteeing adherence to predefined transient and steady-state performance bounds. Crucially, the framework ensures singularity-free control by deliberately excluding barrier functions from the control input, thereby preventing potential singularities when system states approach the performance boundaries. The efficacy of this integrated framework, incorporating model-based PT generation, singularity avoidance, and unwinding-free behavior, is validated through comprehensive quadrotor uncrewed aerial vehicles (UAV) simulations and ground bench tests.