Hi, I'm Pio Ong

I am currently a post-doctoral researcher and a lecturer at California Institute of Technology under the supervision of Prof. Aaron Ames. My current main research focus is on safe intermittent control of satellites using tools like event-triggered control and control barrier functions. I received a Bachelor's degree in Aerospace Engineering from UCSD in 2012, and a Master's degree in Astronautical Engineering from USC in 2013. During Fall and Winter of 2014, I worked as an intern at Space Exploration Technologies Corp (SpaceX), which has sparked my interests in studying control theory. In 2022, I received my Ph.D. degree from the University of California, San Diego (UCSD), and my Ph.D. advisor was Prof. Jorge Cortés.

Email: pioong@caltech.edu

Academic CV

News

Journal Paper Accepted

Our paper “Nonsmooth control barrier function design of continuous constraints for network connectivity maintenance” is accepted for publication in Automatica.

See Paper
June 2023

Start Teaching

My position as a lecturer at Caltech began. For the Spring quarter of 2023, I was hired to teach an undergraduate course on the introduction to controls (CDS 110/ChE 105).

April 2023

Papers Submitted

We submitted two papers to CDC 2023.

See Paper 1 See Paper 2
March 2023

Papers Accepted

Both papers we submitted to CDC 2022 get accepted.

See Paper 1 See Paper 2
September 2022

Start Postdoc

I started my post-doctoral research under the guidance of Prof. Aaron Ames at Caltech.

Prof Ames's Website
January 2022

Defended Thesis!

I successfully defended my thesis, and therefore, finished my studies at UCSD. Thank you Prof. Jorge Cortes for being an awesome advisor.

December 2021

Paper Submitted

We submitted a paper “Performance-barrier-based event-triggered control with applications to network systems” to Transactions on Automatic Control.

See Paper
August 2021

Research Interests

Event-triggered control (ETC) is a tool for accomplishing control tasks while conserving resource usages. Our research involves pushing the boundary on the efficiency of ETC, and at the same time, tying in performance criteria to the trigger design. In addition, we tackle unsolved problems in the area, such as Zeno-free distributed trigger design, and interesting applications of ETC, such as human-robot interaction.

Control barrier functions (CBFs) are employed to address safety concerns, i.e., the possibilities of system trajectory to evolve to undesirable states. Our research focuses on the implementation issues of a CBF-based feedback controller. This includes both smoothness (or continuity) property and resource usage of the controller. One interesting application of CBF we study is connectivity maintenance of a multi-robot system.

Our research explores the excitiing possibilities of applying novel techniques, e.g., event-triggered control and control barrier functions, to network systems in a distributed way. We use tools like graph theory and dynamic average consensus to help with analyses. Applications we look at include multi-robot systems and power systems.

Smoothness property is a desirable trait for real-world applications. Particularly, following Sontag's famous universal formula, we develop our own version of such formula that also takes into account safety criterion from a control barrier function, in addition to the Lyapunov's condition for stability.

Publications

Journal Papers

  1. P. Ong, B. Capelli, L. Sabattini, J. Cortés. Nonsmooth control barrier function design of continuous constraints for network connectivity maintenance
    Automatica, to appear
  2. P. Ong, J. Cortés Performance-barrier-based event-triggered control with applications to network systems
    IEEE Transactions on Automatic Control, submitted
  3. A. J. Taylor, P. Ong, J. Cortés, A. D. Ames. Safety-critical event triggered control via input-to-state safe barrier functions
    IEEE Control Systems Letters 5 (3) (2021), 749-754
    (First two authors contributed equally to the paper)
  4. P. Ong and J. Cortés. Opportunistic robot control for interactive multiobjective optimization under human performance limitations
    Automatica 123(2021), 109263

Conference Papers

  1. P. Ong, A. D. Ames. “Intermittent Safety Filters for Event-Triggered Safety Maneuvers with Application to Satellite Orbit Transfers”
    Proceedings of the IEEE Conference on Decision and Control, Marina Bay Sands, Singapore, submitted
  2. G. Bahati, P. Ong, A. D. Ames. “Violation-Free Inter-Sampling Safety: from Control Barrier Functions to Tunable Controllers with Input-to-State Safety Guarantees”
    Proceedings of the IEEE Conference on Decision and Control, Marina Bay Sands, Singapore, submitted
  3. P. Ong, G. Bahati, A. D. Ames. “Stability and safety through event-triggered intermittent control with application to spacecraft orbit stabilization”
    Proceedings of the IEEE Conference on Decision and Control, Cancun, Mexico, 2022, pp. 453-460
  4. A. J. Taylor, P. Ong, T. G. Molnar, A. D. Ames. “Safe backstepping with control barrier functions”
    Proceedings of the IEEE Conference on Decision and Control, Cancun, Mexico, 2022, pp. 5775-5782
  5. P. Ong, B. Capelli, L. Sabattini, J. Cortés. “Network connectivity maintenance via nonsmooth control barrier functions”
    Proceedings of the IEEE Conference on Decision and Control, Austin, Texas, 2021, pp. 4780-4785
    (First two authors contributed equally to the paper)
  6. A. J. Taylor, P. Ong, J. Cortés, A. D. Ames. “Safety-critical event triggered control via input-to-state safe barrier functions”
    Proceedings of the IEEE Conference on Decision and Control, Jeju Island, South Korea, 2020
    (First two authors contributed equally to the paper)
  7. P. Ong and J. Cortés. “Universal formula for smooth safe stabilization”
    Proceedings of the IEEE Conference on Decision and Control, Nice, France, 2019, pp. 2373-2378
  8. P. Ong and J. Cortés. “Event-triggered control design with performance barrier”
    Proceedings of the IEEE Conference on Decision and Control, Miami Beach, Florida, 2018, pp. 951-956
  9. P. Ong and J. Cortés. “Event-triggered interactive gradient descent for real-time multi-objective optimization”
    Proceedings of the IEEE Conference on Decision and Control, Melbourne, Australia, 2017, pp. 5445-5450