Comment on “Stabilization with guaranteed safety using Control Lyapunov–Barrier Function”

Abstract Recently, Romdlony and Jayawardhana (2016) proposed control Lyapunov–Barrier functions (CLBFs) for the stabilization of nonlinear control systems while avoiding a bounded set of unsafe states. We demonstrate that CLBFs used in Romdlony and Jayawardhana (2016, Prop. 3 and 5) cannot exist. Critically, this implies that the examples discussed in Romdlony and Jayawardhana (2016) do not satisfy the stated assumptions on CLBFs.