Fully Actuated Manifold Constraint Based Output Feedback Control for Input-Constrained Uncertain Nonlinear Systems

2026-05-20

AI Summary

This work addresses the challenge of simultaneously achieving prescribed accuracy and control flexibility for input-constrained, model-unknown, time-varying nonlinear systems, particularly in the presence of actuator saturation. To this end, a low-complexity, model-free output-feedback control method is proposed within the fully actuated system framework. By introducing a nonlinear manifold constraint together with an error-driven flexible constraint mechanism, the approach extends existing linear manifold control to general nonlinear settings, accommodating diverse constraint types. The method ensures prescribed-performance control within finite or fixed time and enables adaptive regulation under unknown saturation conditions. Simulation results demonstrate that the proposed strategy effectively maintains desired performance both before and after actuator saturation in second-order and higher-order nonlinear systems.

Abstract

This paper presents a low-complexity, model-free, output-feedback controller for a class of unknown time-varying nonlinear systems with unknown input constraints. The controller achieves the preset control accuracy when the actuator is not saturated and maintains flexible control accuracy after actuator saturation. This result extends existing constraint control methods for linear manifolds to a more general form, including the construction of nonlinear manifolds and various types of constraints, thereby achieving preset control accuracy within finite or fixed time. Additionally, flexible control under unknown saturation is achieved through the construction of an error-driven flexible constraint. Finally, second-order and higher-order control examples and simulations are provided.

Problem

• output feedback control
• input-constrained
• uncertain nonlinear systems
• actuator saturation
• manifold constraint

Innovation

• fully actuated manifold
• output feedback control
• input constraints
• nonlinear systems
• flexible constraint