  Balancing safety and performance is one of the predominant challenges in
modern control system design. Moreover, it is crucial to robustly ensure safety
without inducing unnecessary conservativeness that degrades performance. In
this work we present a constructive approach for safety-critical control
synthesis via Control Barrier Functions (CBF). By filtering a hand-designed
controller via a CBF, we are able to attain performant behavior while providing
rigorous guarantees of safety. In the face of disturbances, robust safety and
performance are simultaneously achieved through the notion of Input-to-State
Safety (ISSf). We take a tutorial approach by developing the CBF-design
methodology in parallel with an inverted pendulum example, making the
challenges and sensitivities in the design process concrete. To establish the
capability of the proposed approach, we consider the practical setting of
safety-critical design via CBFs for a connected automated vehicle (CAV) in the
form of a class-8 truck without a trailer. Through experimentation we see the
impact of unmodeled disturbances in the truck's actuation system on the safety
guarantees provided by CBFs. We characterize these disturbances and using ISSf,
produce a robust controller that achieves safety without conceding performance.
We evaluate our design both in simulation, and for the first time on an
automotive system, experimentally.
