2 research outputs found
Safety-Critical Event Triggered Control via Input-to-State Safe Barrier Functions
The efficient utilization of available resources while simultaneously
achieving control objectives is a primary motivation in the event-triggered
control paradigm. In many modern control applications, one such objective is
enforcing the safety of a system. The goal of this paper is to carry out this
vision by combining event-triggered and safety-critical control design. We
discuss how a direct transcription, in the context of safety, of
event-triggered methods for stabilization may result in designs that are not
implementable on real hardware due to the lack of a minimum interevent time. We
provide a counterexample showing this phenomena and, building on the insight
gained, propose an event-triggered control approach via Input to State Safe
Barrier Functions that achieves safety while ensuring that interevent times are
uniformly lower bounded. We illustrate our results in simulation.Comment: 6 pages, 2 figures, submitted to L-CSS + CDC 202
Resource-Aware Discretization of Accelerated Optimization Flows
This paper tackles the problem of discretizing accelerated optimization flows
while retaining their convergence properties. Inspired by the success of
resource-aware control in developing efficient closed-loop feedback
implementations on digital systems, we view the last sampled state of the
system as the resource to be aware of. The resulting variable-stepsize
discrete-time algorithms retain by design the desired decrease of the Lyapunov
certificate of their continuous-time counterparts. Our algorithm design employs
various concepts and techniques from resource-aware control that, in the
present context, have interesting parallelisms with the discrete-time
implementation of optimization algorithms. These include derivative- and
performance-based triggers to monitor the evolution of the Lyapunov function as
a way of determining the algorithm stepsize, exploiting sampled information to
enhance algorithm performance, and employing high-order holds using more
accurate integrators of the original dynamics. Throughout the paper, we
illustrate our approach on a newly introduced continuous-time dynamics termed
heavy-ball dynamics with displaced gradient, but the ideas proposed here have
broad applicability to other globally asymptotically stable flows endowed with
a Lyapunov certificate