Design coupling analysis in multidisciplinary design optimization and control co-design

Fernandez Bravo, Elena

Permalink

https://hdl.handle.net/2142/132533 Copy

Description

Title

Design coupling analysis in multidisciplinary design optimization and control co-design

Author(s)

Fernandez Bravo, Elena

Issue Date

2025-11-26

Director of Research (if dissertation) or Advisor (if thesis)

Allison, James T

Doctoral Committee Chair(s)

Ornik, Melkior

Committee Member(s)

• Wang, Pingfeng
• Coverstone, Victoria

Department of Study

Aerospace Engineering

Discipline

Aerospace Engineering

Degree Granting Institution

University of Illinois Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

• Design coupling
• Multidisciplinary design optimization
• Control co-design
• Optimization
• Optimization problem formulation
• Spacecraft control
• Floating offshore wind turbine

Abstract

The design of complex engineering systems involves multiple interconnected, or coupled, disciplines. The relationships between these disciplines are not always well-known, especially for emerging technologies. Optimizing these systems can be a challenging task, especially if the designer has limited knowledge of the system at hand. One of the questions that arises early in the optimization problem formulation is what design variables to optimize. Complex systems may have hundreds of design variables, and it might not be possible or even desirable to optimize them all. More clear understanding of relationships between problem variables can aid optimization specialists in value-added problem definition. This work focuses on extracting valuable insights from design coupling analysis to make optimization problem formulation decisions, focusing on design variable selection. These decisions may be based on expert intuition, but important problem formulations may be missed by relying solely on intuition. This work focuses on multidisciplinary design optimization (MDO) and control co-design (CCD) problem formulation. By performing design coupling analysis (DCA), problem formulations that reduce the computational expense associated with solving MDO and CCD problems can be identified. Furthermore, the use of design coupling analysis may identify non-obvious problem formulations and provide design insights that lead to new engineering system designs. Both MDO and CCD present a number of challenges for the study of design coupling, making it necessary to develop new methods to estimate coupling. This dissertation expands existing work for design coupling estimation in MDO by considering together the effect of design variables on the objective function, and on each other. Previous work in design coupling estimation in CCD imposed some restrictive assumptions, such as considering a limited view of coupling or assuming that the control variables are scalar quantities. Here, many of those restrictions are lifted. The design coupling methods proposed in this work allow for bidirectional coupling, that is, plant and control affect each other, and for time-varying control inputs. The proposed work is investigated in three case studies spanning two rich applications, spacecraft design and attitude control, and floating offshore wind turbines. The case studies are used to demonstrate the quantification of design coupling and the use of this information to formulate optimization problems.

Graduation Semester

2025-12

Type of Resource

Thesis

Handle URL

https://hdl.handle.net/2142/132533

Copyright and License Information

Copyright 2025 Elena Fernandez Bravo

Owning Collections