I’m a co-founder and CTO of Ghost Robotics (YouTube, Twitter), a startup company commercializing legged robotics in Philadelphia. The company currently has two products, a 45kg quadruped aimed at industrial applications, and a 12kg quadruped aimed at research applications.

Previously, I completed a postdoc at Harvard’s microrobotics lab advised by Rob Wood, where I researched design of micro-scale flapping robots, as well as strategies for their control.

I received my PhD in Sep 2017, at the GRASP laboratory (Kodlab) in the University of Pennsylvania advised by Dan Koditschek.

The main thread tying all of my work has been bio-inspired design and control strongly anchored in empirical robotics. My research has focused on examining the strengths and weaknesses of modular and hierarchical control strategies, as well as demonstrating efficient and effective control of dynamic locomotion in a way that generalizes across platforms (quadruped, tailed biped, …) and behaviors (hopping, running, …).

📜 Curriculum Vitae (CV)

I talk a bit about some of my academic work on this website - see all the posts on papers.

In the posts on this website, I try to communicate some of the content of the papers in simpler intuitive language with the hope that it will help and inspire readers.

For a more complete list of papers, see my Google scholar page.

🎓 Education

• Postdoctoral fellow. Harvard University, Cambridge, MA. Advisor: Dr. Rob Wood. 2019–2020.
• Postdoctoral fellow. University of Pennsylvania, Philadelphia, PA. Advisor: Dr. Daniel E. Koditschek. 2017–2018.
• Ph.D. University of Pennsylvania, Philadelphia, PA. Advisor: Dr. Daniel E. Koditschek. Ph.D. thesis: Modular Hopping and Running via Parallel Composition. 2010–2017.
• M.S. (Mech Engg), B.S. (Engg Mech), B.S. (Appl Math). Johns Hopkins Univ, Baltimore, MD. Advisors: Dr. Noah J. Cowan (research), Dr. Alison Okamura (academic); GPA: 3.96/4.00; M.S. thesis: Neuromechanical Control of Paddle Juggling. 2006–2010.

🏢 Work experience excluding teaching

• Ghost Robotics Corp. Co-founder & CTO. Co-founded a company commercializing legged robots. Responsibilities include assembling an engineering team starting from the two co-founders to 45+, mobility algorithms for robust deployment, architecting and implementing the electrical/computing subsystem (comprised of mass-manufacturable custom electronics), firmware and low-level software. 2015–now
• LIMBS lab (Noah Cowan), JHU. Undergrad research assistant: neuromechanical control of juggling; SLAM on graphs. This part-time research resulted in a conference paper (WAFR 2008), a master’s thesis, and a 3rd author journal paper. 2007–10
• Advanced Academic Programs, JHU. Web/database developer (Coldfusion/SQL). 2006–10
• Academic Advising, JHU. Tutor (Physics I/II, Calculus I/II/III). 2007–08
• Residential Life, JHU. Resident advisor

🏆 Honors and awards

• Outstanding reviewer awards: RAL, Bioinspriation & Biomimetics, IOP publishing
• Best Doctoral Dissertation Award for the 2017-2018 Academic Year. UPenn Electrical and Systems Engineering dept. 2018
• James S. McDonnell Postdoctoral Fellowship Winner. $200,000 award for 2-3 years. 2017
• Robert George Gerstmeyer Award. For academic achievement (JHU Mech. Engg. Department) 2008–09
• Provost’s Undergraduate Research Award. For summer research (JHU) 2008–09
• Tau Beta Pi, Pi Tau Sigma Engg. honor societies. Inductee (JHU) 2008
• International Scholarship. Merit-based full-tuition scholarship (JHU) 2006–10

🎤 Invited talks

I have also given a number of invited talks separate from conference paper presentations, some of which I’ve written posts about:

• 2022/06 GRASP Industry Day – Introduction to Ghost Robotics
• 2022/05 ICRA impulsive workshop – Design and control of insect-scale bees and dog-scale quadrupeds
• 2022/05 Kodfest – Kodlab 2010-2017
• 2021/09 IROS actuator workshop – Operating at force, power, and thermal limits in electrically-actuated commercial legged robots
• 2021/06 ICRA legged robot workshop – Perception-aided control and planning with reduced order models
• 2021/05 ICRA teleoperation workshop – Shared autonomy and user interaction in commercial legged robots
• 2021/04 CMU RI Seminar – Design and control of insect-scale bees and dog-scale quadrupeds
• 2021/02 IFRR quadruped robotics colloquium – State of the art in quadrupedal robotics
• 2020/07 RSS contact workshop – Reacting to contact
• 2020/07 ICRA legged workshop – Designing power-efficient quadrupedal robots for commercial applications at Ghost Robotics
• 2019/09 GRASP 40 year celebration – Perspective on Academia vs. Industry
• 2019/07 ACC templates workshop – Optimal Control Synthesis via Compositions of Reduced-Order Models (Templates)
• 2019/05 ICRA legged workshop – Connecting Today’s Applications for Commercial Legged Robots to their Design and Control
• 2018/10 IROS templates workshop – Template Composition for Synthesis of New Behaviors from Simpler Constituents
• 2018/06 RSS 2018 tails workshop – Tail design and control for a tail- and hip-energized and -stabilized bipedal hopping robot
• 2018/05 ICRA actuator workshop – Platform design using dynamic motor, electronics, and transmission models
• 2018/05 ICRA 2018 multilegged robots workshop – Toward robust locomotion subject to variations in robot scale, mass, payload, and environmental conditions
• 2017/10 UC Berkeley biomechanics seminar – Modular hopping and running (for biologists and engineers)
• 2017/06 UMichigan, JHU seminar series – Stable hopping and running from compositions of dynamical primitives
• 2017/02 CMU bipedal seminar; UW seminar – Anchored Behaviors from Template Compositions
• 2017/02 TRI (Palo Alto, CA), Google (Mountain View) – Mechanically Simple, Behaviorally Versatile Quadrupeds
• 2017/01 Neuroscience meeting (Tulane) – Reactive coordination: stabilizing common quadrupedal gaits without CPGs
• 2015/10 Fall UPenn ESE PhD Colloquium – Sequential, Parallel and Symbolic Compositions
• 2015/06 AMAM 2015 (Cambridge, MA) – Anchor synthesis via template composition

🧑‍🏫 Activities, teaching, and service

• Reviewer. IJRR, Bioinspiration & Biomimetics, Automatica, T/RO, RA/L, European Journal of Physics, Control Engineering Practice, ICAR, ICHR, ICRA, IFACWC, IROS, SYROCO, WAFR, MCA, Autonomous Robots. Peer review isn’t a perfect system, but it’s the best system we have, and we all need to take pride in our efforts there to justify the time we volunteer to it.
• Mentoring. Mentored undergraduate, masters, and junior PhD students to write papers accepted to ICRA/IROS 2013–18
• UPenn guest lecturer. ESE 512 (graduate dynamical systems), MEAM 517 (Control and Optimization with Applications in Robotics), MEAM 520 (Intro to Robotics) 2017–now
• UPenn/Coursera instructor. Robotics specialization instructor for Mobility, Capstone courses; developed curriculum including topics like how animals and robots are designed and how they move, linearized control and balancing a mobile inverted pendulum 2016
• UPenn TA. TA for ESE 201 (undergraduate dynamical systems), ESE 512 (graduate dynamical systems) 2011–12
• Outreach. Two-time volunteer / judge at Penn First Lego League (FLL) 2014–16
• Animal welfare. Volunteer at Philadelphia Animal Welfare Society (PAWS); cat fostering 2014–now
• Hopkins Baja, JHU. Team captain of an engineering design team creating a single-seat offroad vehicle for an SAE-organized collegiate competition; suspension and steering design lead 2006–10
• JH Math Club, JHU. Part of JHU Putnam team; contributed problems to JH math tournament for HS students 2006–09 ASME chapter, JHU. Secretary/treasurer 2006–10

⚙️ Engineering skills

• Electrical. PCB schematic&layout; high-power electronics including brushless motor controllers capable of 1.5KW (continuous), >10KW (peak); versatile Cortex A53/M7 hybrid architecture mainboards for robot control
• Firmware. Experience designing and implementing multi-processor real-time robotic control systems; created an Arduino-like set of libraries for STM32F3/4 microcontrollers (open-source Koduino repository); extensive experience with Cortex-M4/M7 microcontrollers; communication protocols (EtherCAT, Ethernet, USB, RS485 9-bit addressing multiprocessor communication, USART, SPI, I2C); RT Linux; advanced motor control (FOC, field-weakening, etc.).
• Software. Architecture and implementation of Ghost Robotics robot and mobility software and SDK; high-performance concurrent C++ running on embedded platforms for real-time control; physics simulation with Bullet physics
• Mechanical. Overall design of the Penn Jerboa and Delta Hopper robots, high-level design of Ghost Robotics robots; chassis, suspension, and steering design for a single-seat 200 kg Baja SAE offroad vehicle

⚽ Hobbies

It is pretty tough to keep up with all my hobbies, but I’m doing my best.

Some of my favorite hobbies have been ultimate frisbee with PADA, fostering kittens and volunteering at PAWS.

I used to have pretty good (musical) keyboard chops (as much as you can without any formal music theory) and still have great relative pitch.

I used to be decent at juggling (basic 3-ball patterns up to Mill’s mess, 4-ball cascade on a good day).

I am drawn to games that require rapid pattern-matching, and enjoy casual art.

📞 Contact me

Links are in the footer. If you’d like to get in touch with me, feel free to DM me on Twitter.