A Composite Control Framework of Safety Satisfaction and Uncertainties Compensation for Constrained Time-Varying Nonlinear MIMO Systems

In this article, we propose a composite control framework for time-varying nonlinear multiple-input–multiple-output (MIMO) systems with safety constraints and unknown dynamics. The control framework combines control barrier functions (CBFs) and high-order CBFs (HoCBFs) with an extended state observer (ESO) to handle arbitrary relative-degree constraints in the presence of system uncertainties and output measurements only. Then, the ESO-CBF/HoCBF-based safety control schemes are obtained by solving quadratic programs (QPs) to ensure the safety of closed-loop control systems. Consequently, the safety satisfaction and uncertainties compensation objectives can be achieved simultaneously. Finally, simulations and experiments are conducted to verify the effectiveness of the proposed safety control schemes.