I am now an engineer with the US federal government, doing things that I can't really discuss. This page mostly dates from my days as a professor, and before that as research faculty at the University of California, Los Angeles. I keep my hand in as a research professor at GWU, and papers are still being written. The work with the Psychology department in particular remains a focus. Also, I have been working with a doctoral student in the Civil Engineering department in the field of automated lane change. This involves automobiles changing lanes to avoid collisions. Several papers have already been written as a result of this work, as well.

In Memoriam

I met Doug Caldwell in the early 1990's, when he was the leader of a group of UCLA students on a quixotic quest to build a rocket. The Space Projects Group eventually got their rocket off the ground, and Doug eventually got his doctorate. He was already a successful scientist and entrepreneur. He worked at JPL, and later helped launch Ecliptic Enterprises and Angeles Energy. We was also a competitive cyclist. He was killed on August 20, 2010, when he was struck from behind while riding his bicycle to work.

It's hard to come up with things to say about friends who have died, and it doesn't make a lot of sense, anyway. If you knew the person, you have your own thoughts and memories, and if you didn't, somebody's eulogy for them doesn't much matter. But Doug was a good friend and I am saddened that he is gone.

Among the people I worked with at GWU was Steve Pothier. He walked into my office one afternoon and introduced himself. He wanted to do research and keep himself busy, and as he was an airline pilot, he had plenty of free time (FAA rules limit how many days he could work). He turned out to be an excellent coworker, in several areas. His biggest contribution to the students at GWU was his tireless work leading the team that built the GWU float for the inaugural parade in January, 2009.

Steve died on November 30, 2009, a week after he and I were in Florida at an ASME conference. He had recently been diagnosed with an agressive brain cancer. He will be missed by all who had the good fortune to enjoy his company and share his energy and enthusiasm. There are a lot of things that could be said about him, but I think one of the things that best describes him was his reaction when the Dean of Engineering at GWU wanted to recognize him for his efforts on the inaugural float. Steve was angry. He genuinely felt that his weeks of living on a few hours of sleep, his constant efforts, were not worthy of note. His comment to me was, "The students did it!" He wanted nothing to diminish their work.

Research Interests and Activities

• Autonomous formation flight of aircraft for drag reduction

  It is well-known among pilots that one airplane flying in the upwash of another uses less fuel than when flying alone. Since it adds nothing to the fuel use of the leader, this effect can be used to greatly increase the overall efficiency of the pair, or larger group, of planes. For a brief description of the aerodynamics of formation flight, go here....

  This idea has been at the heart of a research effort that has been underway at UCLA for over five years, in partnership with Boeing North American and NASA's Dryden Flight Research Center. Unlike many university research efforts, this one has included a great deal of hardware and experimental work. The main thrust of this work has been the development of instrumentation to precisely measure the relative position, velocity, and attitude of two (or more) moving vehicles. This is done using a blend of Global Positioning Systen (GPS) and inertial measurement instruments. As a part of the effort, these instruments will be used to control a pair of F-18's in formation flight at Dryden.

  The effort did not start out with fighters in mind. Originally, the intent was that the gains in aerodynamic efficiency would enable solar powered formation flight. This was an attempt to create a formation of aircraft that would fly for all intents and purposes indefinitiely at a very high altitude, for the purposes of observation or communications relay.

  Test flights with the Mule: As part of the instrumentation development effort, several flight tests involving remotely piloted vehicles have been carried out, at El Mirage dry lake bed and, more recently, at MacMillan Airfield on Camp Roberts, a California National Guard base near Paso Robles. These flights have used the Mule, an R/C aircraft, and the flight control computer mentioned above. Autonomous flight was achieved in November of 1998. For more about this effort, and pictures of the Mule in flight, go here....

• Peak-Seeking Control Theory

  In order to get the maximum benefit from formation flight, it is necessary for the trailing plane to fly in the proper position relative to the leader (see the aerodynamics discussion mentioned above). Since this position is not well known in advance, and changes with flight condition, it is likely that the trailing craft will have to search it out in flight.

  This is an example of peak-seeking control, also known as extremum control. The basic idea in this class of problems is that a system is trying to optimize some function of the states of the system. In this case, the function is efficiency, and the states are the lateral and vertical relative positions. This case is complicated by the fact that the system dynamics are directly coupled to the function being optimized.

• Dynamics of Clustered Satellites.

  There is a great deal of interest these days in the idea of putting groups of satellites into space, such that all of the satellites stay close to each other while the cluster as a whole orbits the Earth (and in one case the sun -- check out the LISA mission at JPL). The relative motion of these satellites is not obvious. I have written one paper on the subject, and it continues to be a topic of interest and active research.

Newer activity:

• Mechanics and Dynamics of Articulated Swimmers

  Research being performed as part of GWU Centre for Biomimetic and Bio-Inspired Engineering (COBRE). The three-link swimmer is the simplest device that can mimic some of the motions of an eel, and is considered the simplest device capable of self-propulsion in water (neglecting viscosity). One of my doctoral students is modeling the dynamics and conducting experimental validation.

• Time-course of Scene Perception and Recognition

  Collaboration with John Philbeck, Psychology Department, GWU.
  We have developed and continue to improve a tachistoscope, a device that allows very brief (from a few milliseconds to a few seconds) views of a scene. Our device also allows masking afterwards. This allows investigation into how quickly perception occurs, and what influences it. Further collaborators include Stephen Pothier (Visiting Scholar, MAE) and Daniel Gajewski (Post-doc, Psychology).

• Effects of Rotations on Perception of Position and Orientation.

  Collaboration with John Philbeck, GWU Department of Psychology.
  We use a rotary platform with wireless communication (designed and built by myself and students in the CVSG) to rotate subjects with precise velocity profiles. The experiments investigate the interactions between visual and non-visual impressions of rotation and position. Professor Philbeck and his students are funded through an NIH RO1 grant for this project.

• Dynamics and Modeling of the Subtalar Joint.

  Collaboration with Dr. Frances Sheehan Gavelli, NIH.
  Investigation of the bearing surfaces of calcaneus (heel bone) that support the talus. These surfaces comprise the sub-talar joint, which is relatively under-researched. The immediate question is what role each of the three surfaces play in defining the relative motion of the bones.
  James Stephenson, an undergraduate in the Mechanical and Aerospace Engineering department, was given a fellowship to pursue research in this area. As a result of our efforts, he was sent to Bologna, Italy to present some of our preliminary work at the conference of the Internation Foot and Ankle Biomechanics (iFAB) community.

Selected Publications

• Damoon Soudbakhsh, Azim Eskandarian, and David Chichka, "Vehicle Evasive Maneuver Trajectory Optimization Using Collocation Technique." ASME Dynamic Systems and Control (DSC) 2010 Conference, Cambridge MA, September 13-15.
• Arthur, J.A, Philbeck, J.W., and Chichka, D. "Non-sensory inputs to angular path integration." Journal of Vestibular Research. 19(3),pp. 111-125.
• Daniel A. Gajewski, John W. Philbeck, Stephen Pothier, and David Chichka, "From the Most Fleeting of Glimpses: On the Time Course for the Extraction of Distance Information", Psychological Science, August 31, 2010.
• Sargent, J., Dopkins, S, Philbeck, J. & Chichka, D. (2010). "Chunking in spatial memory." Journal of Experimental Psychology: Learning, Memory & Cognition, 36(3), 576-89.
• Stephen Pothier, John Philbeck, David Chichka, and Daniel Gajewski, "Tachistoscopic exposure and masking of real three-dimensional scenes", Journal of Behavior Research Methods, in press.
• David Chichka, James Stephenson, Antonio Paulic, and Frances Sheehan, "Bearing surface modeling of the talus and calcaneus", Journal of Foot and Ankle Research; 2008; 1(Suppl 1) O43. Published online Sept 26, 2008. Originally presented at the First Congress of the International Foot & Ankle Biomechanics (i-FAB) community, 4-6 September 2008, Bologna, Italy. Abstract of the presentation here.
• B.J. Duffy and D.F. Chichka, A Study of Eccentric Orbit Circularization using Low-Thrust Propulsion", the F. Landis Markley Astronautics Symposium, June 30 to July 2, 2008, Cambridge, MD. Submitted to the Journal of the Astronautical Sciences.
• Arthur, J., Philbeck, J., and Chichka, D. "Spatial memory enhances the precision of angular self-motion updating", Experimental Brain Research, v.183, no.4, December, 2007, pp. 557-568.
• Warren Greczyn and David Chichka, ``Opportunities for Deflection of Asteroid Threats'', Proceedings of the 2007 Planetary Defense Conference, Washington, DC, March 5-8, 2007.
• W.R. Williamson, M. Abdel-Hafiz, I. Rhee, E.J. Song, J. Wolfe, D. Cooper, D.F. Chichka, and J.L. Speyer, "An Instrumentation System Applied to Formation Flight", IEEE Transactions on Control System Technology, v. 15, no. 1, January 2007, pp. 75-85. (PDF)
• D. F. Chichka, J. L. Speyer, C. L. Fanti, and C-G park, ``Peak-Seeking Control for Drag Reduction in Formation Flight", AIAA Journal of Guidance, Control, and Dynamics, v. 29, no. 5, Sep-Oct 2006, pp.1221-1230.
• Rajtilok Chakravarty and David F. Chichka, "Including Vision Information in a GPS/INS Fusion Filter'', Proceedings of the 2006 AIAA Guidance, Navigation, and Control Conference, Keystone, Colorado, August, 2006.
• Belanger, G.M., Slava Ananyev, J. L. Speyer, D. F. Chichka, and J.R. Carpenter, "Decentralized Control of Satellite Clusters under Limited Communication", AIAA Journal of Guidance, Control, and Dynamics, v. 29, no. 1, Jan-Feb 2006, pp.134-145.
• D E Chang, D. F. Chichka, and J. E. Marsden, ``Lyapunov Transfer Between Elliptic Orbits", Journal of Discrete and Continuous Dynamical Systems, Series B, 2, Jan-Feb 2002, 57-67.
• D. F. Chichka, ``Satellite Clusters with Constant Apparent Distribution'', AIAA Journal of Guidance, Control, and Dynamics, Volume 24, Number 1, Jan-Feb 2001, pp. 117-22. (An early version was presented as Paper AAS 99-309, ``Dynamics of Clustered Satellites via Orbital Elements'', at the 1999 AAS/AIAA Astrodynamics Specialist Conference, Girdwood, Alaska, August, 1999).
• J. L. Speyer, R. N. Banavar, D. F. Chichka, and I. Rhee, ``Extremum Seeking Loops with Assumed Functions", Proceedings of the 39th IEEE Conference on Decision and Control, Sydney, Australia, December, 2000.
• R. N. Banavar, D. F. Chichka, and J. L. Speyer, ``Convergence and Synthesis Issues in Peak-Seeking Control'', Proceedings of the 2000 IEEE American Control Conference, Chicago, IL, June 28-30, 2000, pp. 438-443. (Expanded version submitted for inclusion in Automatica.)
• D. Chichka, T. Chiu, G. Belanger, W. Williamson, D. Cooper, and J. Speyer, ``A Real Time Hardware-in-the-Loop Simulator for Evaluation of a Distributed, Autonomous F-18 Formation Flight Control System'', Proceedings of the Institute of Navigation (ION) 2000 Technical Meeting, Anaheim, California.
• D. F. Chichka, J. L. Speyer, and C. G. Park, ``Peak-Seeking Control with Application to Formation Flight'', Proceedings of the 38th IEEE Conference on Decision and Control, December 1999.
• D. F. Chichka and J. L. Speyer, ``Solar-Powered Formation-Enhanced Aerial Vehicle Systems for Sustained Endurance'', Proceedings of the IEEE American Control Conference, Philadelphia, PA, June 1998, Vol 2, pp. 684-88.
• J. D. Wolfe and D. F. Chichka, ``An Effective Design Algorithm for Optimal Fixed Structure Control'', Proceedings of the 36th IEEE Conference on Decision and Control, San Diego, California, December 1997, Vol 3, pp. 2625-27.
• J. D. Wolfe, D. F. Chichka, and J. L. Speyer, ``Decentralized Controllers for Unmanned Aerial Vehicle Formation Flight'', AIAA Paper 96-3833, presented at AIAA Guidance, Navigation, and Control Conference, San Diego, California, July 29-31, 1996.
• D. F. Chichka and J. L. Speyer, ``An Adaptive Controller Based on Disturbance Attenuation'', IEEE Transactions on Automatic Control, Vol. 40, No. 11, July 1995.

Some slightly more personal stuff....

The most beautiful woman in the world, to whom I have the privilege of being married.

"Stay me with flagons, comfort me with apples: for I am sick of love."

Some interests of mine:

I am a big fan of Medieval Literature, and of course of Chaucer. I did my seminar work on Spenser's Faerie Queene, which at least partially explains the names of all of the computers in my little domain.

I also enjoy astrology, and especially Vedic astrology. I believe in it about as much as I believe the promises of politicians, but that doesn't keep it from being a lot of fun.

Reading:

Poetry: My favorite poem is " Kubla Khan", by Coleridge, whose "Rime of the Ancient Mariner" and "Christabel" are also incredible. Coleridge makes you wonder why you can't write that way. My second favorite is Tennyson's "Ulysses", and after that comes a welter of others: Anything by Shakespeare, of course; the entirety of the Rubai'at of Omar Khayyam, "Dover Beach" (I know, you had to read it in college and hated it -- read it again, for fun this time); large parts of "Paradise Lost" are simply wonderful (others not so much); Kipling's "Mandalay"; so many more that it's not even possible to make a fair start. I've left out Keats, and Yeats ("... and what rough beast, its hour come round at last / slouches towards Bethlehem to be born?"), and dozens of others. I could spend hundreds of hours on a poetry page, though, so I'm not even going to start.

Social Criticism: There is a school of social criticism that investigates the surprisingly high occurrence of irrationality in public discourse in this country. An excellent case in point is Sleeping with Extra-terrestrials by Wendy Kaminer, which also attacks the often made assertion that "God has been abolished from the public square" in America (the quote is not from the book; it's something I believe I read attributed to Jerry Falwell). In fact, she points out that religion, or at least spirituality, is rampant in America, to the point that it affects our ability to form rational opinions. The book is not the best read I have ever seen, but it is well-researched and definitely worth the time.

Another book on the topic is the late Carl Sagan's The Demon-Haunted World. The overall theme here is the lack of critical thought in public discourse, and the culprit in large part seems to be the lack of training in critical thought in American schools. Sagan begins his book with an anecdote about being recognized by a limo driver who then wants to discuss "science." The subjects brought up by the driver are such things as extra-terrestrials and Atlantis. Consider that the average person is much more likely to hear about these things in the popular media than he is to hear about, say, thermodynamics, and you realize why the driver thinks they are legitimate topics of inquiry.

On another thread entirely are the essays of Barbara Ehrenreich. Almost anything she has to say is worth reading, though my favorite collection of hers is The Worst Years of our Lives, focussing on the Reagan years. The Snarling Citizen just isn't quite as enjoyable. I have not yet read Nickel and Dimed, and the reviews are mixed on it, but you have to assume that if the writing is a little choppy, the work itself will be top-notch. The only thing I've come across that marred my respect for this woman was a positive blurb from her on the jacket of Backlash, the dangerously bad, vehemently anti-male, and thoroughly anti-thought diatribe by Susan Faludi, which despite being so ridiculous that it names Betty Friedan, for goodness' sake, as a leader of the anti-feminist backlash, still was hailed in many circles as a major triumph. (Friedan's motivation for attempting to subvert and destroy a movement to which she devoted her life is given as jealousy of Gloria Steinem.) Faludi's book is useful for pointing out how mindless the media can be in reporting on gender issues (as well as just about anything else). For anything beyond that, of course, it is not only useless but dangerous.

A little too Texas-centric to be for everyone's taste, but completely wonderful, are the essays and columns of Molly Ivins.

Escapist Fare: My other reading is pretty eclectic, and nowhere near so high-brow as the last few paragraphs might suggest. I do occasionally stumble across some genuine modern literature, but my off-duty reading tends to be more escapist. A few of my favorite authors (by which I mean I've read just about everything they've ever written), are Alistair MacLean, Donald Hamilton, Robert B. Parker, Louis L'Amour, and John D. MacDonald (especially the Travis McGee stuff, of course). In Science Fiction, nobody ever did it better than Robert A. Heinlein and Isaac Asimov. Recently, I've been working my way through the Anita Blake series by Laurell K. Hamilton, though one gets tired of Anita after a while.

The best novel I've read recently is Galatea 2.2 by Richard Powers. Among the best novels I've ever read are:

• Even Cowgirls Get the Blues and Another Roadside Attraction, by Tom Robbins. Both of them marvelous, though I think Cowgirls is the better of the two. All of Robbins' stuff since these is also good, but I still think he hasn't bettered them.
• Fear and Loathing in Las Vegas, Hunter S. Thompson.
• Time Enough for Love, Robert A. Heinlein.

A couple of friends' pages:

Jonathan Katz is the Technical Director of Facade, a web-stuff firm that will design and host your e-business presence. Jonathan was one of the original web gurus (he had a UCLA home page up two years before UCLA managed an "official" version, back when he ran the CAD lab for the Mechanical and Aerospace Engineering department there). I like the site because of all the cool divination stuff. Jonathan's tarot server was among the first major attractions on the web, earning mentions in Newsweek and several comic strips, among other places.
Jonathan was also on the altar with us when Sohini and I got married.

Hinke Osinga is a friend of mine from Caltech, now a lecturer in mathematics at Bristol.

I met Sasha Volokh several years ago, when I joined the Chaucer Reading Group at UCLA. Sasha is one of the most interesting (read that however you like) people I know. He has since been to graduate and law school at Harvard, and is a visiting professor at Georgetown University Law School.
Sasha was also one of the party on the altar during my wedding.

I met Dong Eui Chang when he was a doctoral student at Caltech. He is now a math professor at the University of Waterloo. back to top