  Friction modeling has always been a challenging problem due to the complexity
of real physical systems. Although a few state-of-the-art structured
data-driven methods show their efficiency in nonlinear system modeling,
deterministic passivity as one of the significant characteristics of friction
is rarely considered in these methods. To address this issue, we propose a
Gaussian Process based model that preserves the inherent structural properties
such as passivity. A matrix-vector physical structure is considered in our
approaches to ensure physical consistency, in particular, enabling a guarantee
of positive semi-definiteness of the damping matrix. An aircraft benchmark
simulation is employed to demonstrate the efficacy of our methodology.
Estimation accuracy and data efficiency are increased substantially by
considering and enforcing more structured physical knowledge. Also, the
fulfillment of the dissipative nature of the aerodynamics is validated
numerically.
