Disturbance Observer-based Robust Integral Control Barrier Functions for Nonlinear Systems with High Relative Degree

In this paper, we consider the problem of safe control synthesis of general controlled nonlinear systems in presence of bounded additive disturbances. Towards this aim, we first construct a governing augmented state space model where the augmented state constitutes the state, control input and the disturbance observer. Next, we propose Disturbance Observer Integral Control Barrier Functions (DO-ICBFs) via which we are able to synthesize safe control inputs by modifying the governing integral control law by adding an auxiliary control input. In contrast to prior methods in literature that consider the worst case disturbance estimate, we leverage a disturbance observer based approach to propose DO-ICBFs. Based on the construction of these DO-ICBFs, they enable state and input constraint satisfaction. Further, we propose Higher Order DO-ICBFs that extend our proposed method to nonlinear systems with higher input relative degree. Numerical simulations are provided to validate our proposed approach.

Citing

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@inproceedings{zinage2023disturbance,
  title={Disturbance Observer-based Robust Integral Control Barrier Functions for Nonlinear Systems with High Relative Degree},
  author={Zinage, Vrushabh and Chandra, Rohan and Bakolas, Efstathios},
  journal={arXiv preprint arXiv:2309.16945},
  year={2023}
}