Robust Safe Control Synthesis with Disturbance Observer-Based Control Barrier Functions

Title	Robust Safe Control Synthesis with Disturbance Observer-Based Control Barrier Functions
Authors	Ersin Das and Richard M. Murray
Source	To appear, 2022 Conference on Decision and Control (CDC)
Abstract	In a complex real-time operating environment, external disturbances and uncertainties adversely affect the safety, stability, and performance of dynamical systems. This paper presents a robust stabilizing safety-critical controller synthesis framework with control Lyapunov functions (CLFs) and control barrier functions (CBFs) in the presence of disturbance. A high-gain input observer method is adapted to estimate the time-varying unmodelled dynamics of the CBF with an error bound using the first-order time derivative of the CBF. This approach leads to an easily tunable low order disturbance estimator structure with a design parameter as it utilizes only the CBF constraint. The estimated unknown input and associated error bound are used to ensure robust safety and exponential stability by formulating a CLF-CBF quadratic program. The proposed method is applicable to both relative degree one and higher relative degree CBF constraints. The efficacy of the proposed approach is demonstrated using a numerical simulations of an adaptive cruise control system and a Segway platform with an external disturbance.
Type	Conference paper
URL	https://arxiv.org/abs/2201.05758?context=cs.SY
DOI
Tag	DM22-CDC
ID	2022b
Funding
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