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University of New Mexico

Electrical and Computer Engineering ETDs

Theses/Dissertations

Reachability

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Full-Text Articles in Engineering

Software Design For Probabilistic Safety: Stochastic Reachability And Circadian Control, Joseph D. Gleason Nov 2019

Software Design For Probabilistic Safety: Stochastic Reachability And Circadian Control, Joseph D. Gleason

Electrical and Computer Engineering ETDs

Stochastic reachability is an important verification tool that provides probabilistic assurances of safety in a variety of contexts. In engineered systems, safety may be synonymous with the ability of the system to avoid "bad" constraints on the state space, that constitute collision, departure from a flight envelope, or other undesirable phenomenon. In biomedical systems, assurance of safety (such as the mandate to ``do no harm'') are considerably complicated by the fact that there is a lack of physics-driven models, extensive signal processing is needed to capture the underlying state of the system, and the stochasticity inherent to the system may …


Verification Of Stochastic Reach-Avoid Using Rkhs Embeddings, Adam J. Thorpe Jul 2019

Verification Of Stochastic Reach-Avoid Using Rkhs Embeddings, Adam J. Thorpe

Electrical and Computer Engineering ETDs

A solution to the terminal-hitting and first-hitting stochastic reach-avoid problem for a Markov control process is presented. This solution takes advantage of a nonparametric representation of the stochastic kernel as a conditional distribution embedding within a reproducing kernel Hilbert space (RKHS). Because the disturbance is modeled as a data-driven stochastic process, this representation avoids intractable integrals in the dynamic recursion of the reach-avoid problem since the expectations can be calculated as an inner product within the RKHS. An example using a high-dimensional chain of integrators is presented, as well as for Clohessy-Wiltshire-Hill (CWH) dynamics.


Scalable Stochastic Reachability: Theory, Computation, And Control, Abraham Puthuvana Vinod Nov 2018

Scalable Stochastic Reachability: Theory, Computation, And Control, Abraham Puthuvana Vinod

Electrical and Computer Engineering ETDs

Guaranteeing safety and performance are crucial components in any control system, and particularly relevant in light of growing interest in reliable autonomy. In safety-critical applications like biomedical devices, spacecraft applications, and self-driving cars, the cost of failure can be severe. Verification provides these guarantees by characterizing the ``good'' initial states or configurations from which a state can be driven to remain within a collection of pre-specified safe sets, while respecting the system dynamics, bounds on control authority, and additive uncertainties. We also wish to design controllers to achieve this objective. This dissertation proposes novel theory and scalable algorithms for tractable …


Computing The Reach-Avoid Set For Space Vehicle Maneuvering In The Presence Of Debris, Matthew Shubert Apr 2017

Computing The Reach-Avoid Set For Space Vehicle Maneuvering In The Presence Of Debris, Matthew Shubert

Electrical and Computer Engineering ETDs

The ability to guarantee the safety of autonomously controlled space vehicles is of great importance to help avoid accidents and ensure mission success. In this paper we investigate the safety verification of a satellite attempting to maneuver to a new position while avoiding multiple pieces of debris. We assume that the satellite, desired rendezvous point, and all debris are near the same circular orbit with dynamics modeled by Clohessy-Wiltshire-Hill (CWH) equations. We will use reachability methods to guarantee the satellite is able to reach a desired point while avoiding all debris. We will first develop a computationally efficient method for …