Feedback Optimization for Freeway Ramp Metering

Online feedback optimization (OFO) is a controller design paradigm for optimizing the steady- state of a dynamical system. OFO uses an optimization algorithm as a feedback controller, and exploits real-time measurements to cope with the uncertainty on the system dynamics and disturbances. On the downside, existing stability guarantees for OFO require the controller to be much slower than the dynamical system; namely, the control gain has to be very small. This “timescale separation” possibly affects transient performance, settling time, and responsiveness to disturbances —especially in problems with high temporal variability. This project investigates conditions under which stability of the closed-loop can be ensured without requiring any timescale separation. To this end, we use the theory of “monotone system”, which applies for instance to freeway traffic models. The student will have the opportunity to learn about OFO and monotone systems, before applying these concepts to a ramp metering problem, both via analytical analysis and numerical evaluation.

Online feedback optimization (OFO) is a controller design paradigm for optimizing the steady-
state of a dynamical system. OFO uses an optimization algorithm as a feedback controller, and exploits
real-time measurements to cope with the uncertainty on the system dynamics and disturbances. On the
downside, existing stability guarantees for OFO require the controller to be much slower than the dynamical system; namely, the control gain has to be very small. This “timescale separation” possibly
affects transient performance, settling time, and responsiveness to disturbances —especially in problems with high temporal variability.
This project investigates conditions under which stability of the closed-loop can be ensured without
requiring any timescale separation. To this end, we use the theory of “monotone system”, which applies
for instance to freeway traffic models. The student will have the opportunity to learn about OFO
and monotone systems, before applying these concepts to a ramp metering problem, both via analytical
analysis and numerical evaluation.

1. Literature review on topics in online feedback optimization and monotone systems 2. Become familiar with OFO algorithms and their implementation (MATLAB/Python/Julia) 3. Analysis and numerical evaluation of OFO algorithms for congestion control in a traffic network model 4. Final report and presentation.

1. Literature review on topics in online feedback optimization and monotone systems

2. Become familiar with OFO algorithms and their implementation (MATLAB/Python/Julia)

3. Analysis and numerical evaluation of OFO algorithms for congestion control in a traffic network
model

4. Final report and presentation.

We are looking for a talented and highly motivated student with a background in Automatic Control/Applied Mathematics or related fields, optimization and MATLAB/Python/Julia programming. The student must be enrolled in a master program. If you have further questions on this project, please do not hesitate to get in contact with us. If you would like to apply for this project, please email your CV (including lists of projects and optionally any document helpful to evaluate your background) and current grade transcript in PDF to: schandraseka@ethz.ch, mbianch@ethz.ch.

We are looking for a talented and highly motivated student with a background in Automatic Control/Applied Mathematics or related fields, optimization and MATLAB/Python/Julia programming. The student must be enrolled in a master program.

If you have further questions on this project, please do not hesitate to get in contact with us. If you would like to apply for this project, please email your CV (including lists of projects and optionally any document helpful to evaluate your background) and current grade transcript in PDF to: schandraseka@ethz.ch, mbianch@ethz.ch.