Robust Adaptive Control Barrier Functions: An Adaptive Data Driven Approach to Safety (Extended Version)
A new framework is developed for control of constrained nonlinear systems with structured parametric uncertainties. Forward invariance of a safe set is achieved through online parameter adaptation and data driven model estimation. The new adaptive data driven safety paradigm is merged with a recent adaptive control algorithm for systems nominally contracting in closed loop. This unification is more general than other safety controllers as closed loop contraction does not require the system be invertible or in a particular form. Additionally, the approach is less expensive than nonlinear model predictive control as it does not require a full desired trajectory, but rather only a desired terminal state. The approach is illustrated on the pitch dynamics of an aircraft with uncertain nonlinear aerodynamics.