Timing in an idealized discrete-time system (top) versus a physical control system running on a non-real-time operating system (bottom).

Principal Investigators

UCSB PI: João P. Hespanha
Email: hespanha @ ece.ucsb.edu
Tel: +1 (805) 893-7042
Fax: +1 (805) 893-3262

This collaborative project involves 4 other universities:
UC Los Angeles (lead),
UC San Diego,
Carnegie Mellon University
University of Utah.

Electrical & Computer Engineering Dept. (ECE)
University of California, Santa Barbara (UCSB)

Postal address:
Room 5157, Harold Frank Hall
Dept. of Electrical & Computer Eng.
University of California
Santa Barbara, CA 93106-9560 USA

quick links

Project Summary

Inexpensive computation and ubiquitous embedded sensing, actuation, and communication provide tremendous opportunities for societal impact, but also great challenges in the design of networked control systems, because the traditional unity feedback loop that operates in continuous time or at a fixed sampling rate is not adequate when sensor data arrives from multiple sources, asynchronously, delayed, possibly corrupted, and — especially important for this project — the different entities that participate in the control system do not share a common clock.

Significant performance gains can be gained by allowing controllers to use timestamps that specify the time at which a particular sensor measured the state (or a portion of it). However, in practice, three types of errors afflict timestamps:

  1. Delays between the time at which the hardware collects the data and the time at which the timestamp is generated (often by software);
  2. Mismatches between the local clock of the sensor that timestamps the data and an absolute time reference;
  3. Mismatches between the local clock of a controller node that processes the data and the absolute time reference.

These errors limit the system’s ability to have an accurate and unified notion of time and we use the term Quality of Time (QoT) to generically denote a characterization of how well one can localize time events with respect to an absolute time reference.

A key goal of this project is to investigate the impact of QoT in the stability and performance of a networked control system. When considering time-stamping errors, we expect the stability conditions to also permit flexibility in terms of tradeoffs between control performance, message rates (related to communication bandwidth), network delays, and QoT. This should enable synergetic system designs, in which control applications make effective use of information about QoT by adapting to it.

With backgrounds across the system stack, the team involved in ROSELINE has the system implementation and applications expertise required to drive and validate the research as well as to transition the research accomplishments into practice via applications involving time synchronization in smart grid, structural health monitoring, and networked control.

Broader impacts resulting from this project

Applications that will accrue increased efficiency and robustness from the more tunable treatment of QoT abound across the entire spectrum of embedded, mobile and Internet-scale CPS, and include important applications in smart grid, factory automation, infrastructure monitoring, and data networks.

Transforming the way time and its quality are managed in hardware, OS, network, and applications presents valuable opportunities to integrate research and education while promoting interdisciplinary learning at K-12 through postgraduate levels. We pursue three educational broader impacts: (i) integration of research into undergraduate and graduate education through shared development of publicly-disseminated modules to be introduced into multiple courses; (ii) direct engagement of undergraduate students in research, and outreach to pre-college students via efforts such as the Los Angeles Computing Circle; and (iii) outreach to potential users through publications, open-source software, and organization of a cross-disciplinary workshop, supplemented by special journal issues.


All the results, including papers, reports, and software are available freely to the research community through the world-wide-web.

The publications based upon research funded by this project can be found at the following URL:

Relevant Courses

  • ECE147C — Control Systems Design Project & ME106A — Advanced Mechanical Engineering Laboratory
  • ECE229 — Hybrid and Switched Systems

Selected talks

"Opportunities and Challenges in Control Systems arising from Ubiquitous Computation and Communication." Keynote talk at the 2014 IEEE Int.~Conf.~on Control and Automation (IEEE ICCA), Taichung, Taiwan, June 2014 and at the at the 1st Multi-symposium on Control Systems (MSCS2014), Tokyo, Japan, Mar.2014.

"Addressing Adaptation and Learning in the Context of MPC and MHE.'' Invited talk at the Workshop on Recent Advances and Future Directions on Adaptation and Control, Chicago, Illinois, July 2015.

"The Next Internet: Risks and Rewards with the Internet of Things.'' Panelist at the Central Coast MIT Enterprise Forum, Santa Barbara, CA, Feb.2015.

Students, Postdocs, and Visitors


Justin Pearson, BS from the University of California, Santa Barbara and MS degree from Stanford University, started PhD in Fall 2012.

Henrique Ferraz, BS from Federal University of Rio de Janeiro, Brazil, started PhD in Fall 2013.


Hari Sivakumar, PhD 2016, BS and MS from Univ. Michigan, Ann Arbor, currently Data Scientist at Facebook, Menlo Park, CA (as of Nov. 2016)

Steven Quintero, PhD 2014, BS from Embry-Riddle Aeronautical University, currently a Controls Engineer at AeroVironment, Simi Valley, CA (as of Oct. 2015)


Masashi Wakaiki, 2014—2016, PhD 2014 (PhD from University of Kyoto, Japan; Assistant Professor at Chiba University, Japan, as of Apr. 2016)

Kunihisa Okano, 2013—2016, PhD 2013 (PhD from Tokyo Institute of Technology, Japan; Assistant Professor at the Tokyo University of Science, Japan, as of Apr. 2016)


This list only contains visitors that stayed at UCSB for 2 weeks or longer (list sorted by date of last departure)

Victor Campus, Federal Univ. of Minas Gerais, Brazil, 8/1/2014-2/1/2015. 

Prof. Adolfo Bauchspiess, Dept. of Electrical Eng., Brasilia University, Brazil, 2/10/2014-8/10/2014.

Prof. Márcio Fantini Miranda, Federal University of Minas Gerais, Brazil, 8/31/2012-08/31/2013.

Prof. Kenji Hirata, Dept. of Mechanical Engineering, Nagaoka University of Technology, Japan, 9/1/08-8/31/09, 9/13/2012-3/31/2013.