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Dissertation Defense: Tianchen Liu

Title: Co-design for Multi-subsystem and Vehicle Routing-and-Control Problems

Author: Tianchen Liu

Date & Time: Friday, May 15, 2020 – 2:00PM.


Professor Shapour Azarm, Chair/Advisor

Professor Nikhil Chopra, Co-advisor

Professor Balakumar Balachandran

Professor Jin-Oh Hahn

Professor Nuno Martins

Professor Miao Yu

Abstract: Co-design refers to the process of integrating optimization of the physical design with a controller for a system. The challenge in co-design is that the optimization is simultaneously applied to both time-invariant (design) and time-variant (state and control) variables, which can be coupled with each other.

The objective of this dissertation is to explore new formulations and approaches in co-design for multi-subsystem and vehicle routing-and-control problems. Specically, four research questions are considered and resolved. In Research Question 1 (RQ1), the critical issue is how to formulate a class of multi-subsystem co-design problems with convexphysical design subproblems and linear quadratic regulator control subproblems, and construct a decentralized solution approach for such problems. In Research Question 2 (RQ2), solution methods for a broader class of multi-subsystem co-design problems than those considered in RQ1 are investigated. In Research Question 3 (RQ3), the question is whether, in the context of co-design, the combined routing and control costs of a feet of vehicles can be improved if optimal control is introduced into the routing. Finally, an extension of RQ3 is considered in Research Question 4 (RQ4), where the possibility of constructing an integrated vehicle routing-and-control problem with load-dependent dynamics is investigated.

Beyond the articles published by the author of this dissertation, the proposed research questions, models and methods presented have not been considered elsewhere in the literature.