Dear Humies Competition Committee,
We would like to register for the 2020 Humies competition. The 11 items requested for our entry are detailed below.
1. THE COMPLETE TITLE OF ONE (OR MORE) PAPER(S) PUBLISHED IN THE OPEN LITERATURE DESCRIBING THE WORK THAT THE AUTHOR
CLAIMS DESCRIBES A HUMAN-COMPETITIVE RESULT;
* Synthetic-analytic behavior-based control framework: Constraining velocity in tracking for nonholonomic wheeled
mobile robots. DOI: 10.1016/j.ins.2019.06.025
* Family of Controllers based on Sector Nonlinear Functions: An Application for First Order Dynamical Systems.
DOI: iet-cta.2019.0680
2. THE NAME, COMPLETE PHYSICAL MAILING ADDRESS, E-MAIL ADDRESS, AND PHONE NUMBER OF EACH AUTHOR OF EACH PAPER(S);
Marlen Meza-Sánchez, Mier y Terán 9109, Mariano Matamoros Sur, Tijuana, Baja California, Mexico, Postal Code 22334.
E-mail: marlen.meza.sanchez@gmail.com
Eddie Clemente, Alisos 136, Praderas del Cipres, Ensenada, Baja California, Mexico. Postal Code 22785.
E-mail: eclemente@ite.edu.mx
María del Carmen Rodríguez-Liñán, Berlin 660-B, Ampliacion Moderna, Ensenada, Baja California, Mexico. Postal Code 22879.
E-mail: macaroli270@gmail.com
3. THE NAME OF THE CORRESPONDING AUTHOR (I.E., THE AUTHOR TO WHOM NOTICES WILL BE SENT CONCERNING THE COMPETITION);
Marlen Meza-Sánchez
4. THE ABSTRACT OF THE PAPER(S);
* Synthetic-analytic behavior-based control framework: Constraining velocity in tracking for nonholonomic wheeled mobile robots
Abstract: This work presents a genetic programming control design methodology that extends the traditional behavior--based control
strategy towards a synthetic-analytic perspective. The proposed approach considers the internal and external dynamics of the system,
providing solutions to a general structure, and including analytic functions, which can be studied within the Control Theory framework.
The method is illustrated for the tracking control problem under bounded velocity restrictions of a nonholonomic wheeled mobile robot.
A classic Control Theory (CT) based controller that solves the tracking problem (but not the velocity constraint requirement) is chosen
from the literature; based on its stability properties, a modified structure where the search of suitable analytic basis behaviors,
fulfilling both control objectives simultaneously, can be introduced. The proposed framework takes the form of a learning process based
on Genetic Programming (GP) which generates a set of nonlinear tracking controllers satisfying pre-specified velocity bounds. A collection
of 9113 suitable nonlinear solutions were obtained to augment the ground controller. Simulations and real-time experiments are performed
to illustrate the effectiveness of the methodology through the testing of the models with the best performance, as well as those with lower
structural complexity.
* Family of Controllers based on Sector Nonlinear Functions: An Application for First Order Dynamical Systems
Abstract: This study proposes the design of a family of controllers based on sector nonlinear functions for First Order Dynamical Systems.
Three new controllers that incorporate this type of functions are presented and analysed to validate our premise. The proposed nominal
controllers, and an augmented version with integral action are presented. Asymptotic stability is proven under Lyapunov theory, and the
controllers' performance is compared against a traditional Proportional controller. An empirically tuned relation depending on a constant
bound value and an operation range is proposed; this is used to compute the gains for each controller. Simulation results with all of the
controllers under saturation bounds are presented to illustrate the effectiveness of the method at solving the output regulation and the
tracking control problems, under practical physical assumptions. The numerical comparison utilises the L_2 and L_\infty norms over the
output error, and over the control variable, applying the same saturation bounds for each controller.
5. A LIST CONTAINING ONE OR MORE OF THE EIGHT LETTERS (A, B, C, D, E, F, G, OR H) THAT CORRESPOND TO THE CRITERIA (SEE ABOVE) THAT THE
AUTHOR CLAIMS THAT THE WORK SATISFIES;
(B) The result is equal to or better than a result that was accepted as a new scientific result at the time when it was published in a
peer-reviewed scientific journal.
(D) The result is publishable in its own right as a new scientific result independent of the fact that the result was mechanically created.
(F) The result is equal to or better than a result that was considered an achievement in its field at the time it was first discovered.
6. A STATEMENT STATING WHY THE RESULT SATISFIES THE CRITERIA THAT THE CONTESTANT CLAIMS (SEE EXAMPLES OF STATEMENTS OF HUMAN-COMPETITIVENESS
AS A GUIDE TO AID IN CONSTRUCTING THIS PART OF THE SUBMISSION);
B) The analytic nature and the passive properties of the functions discovered by the GP approach in the work entitled ‘Synthetic-analytic
behavior-based control framework: Constraining velocity in tracking for nonholonomic wheeled mobile robots’ allowed us to identify a whole
set of functions for the construction of nonlinear controllers for first-order dynamical systems. This set is a particular class of Sector
Nonlinear Functions belonging to sector [0,\infty]. The observed properties of these functions led to a theoretical extension for the
synthesis of a new family of nonlinear controllers that are an alternative to the classical P and PI controllers; the found controllers
offer very similar performance to that of the classical ones. In addition, these nonlinear controllers are attractive since they are
globally asymptotically stable, as demonstrated by the Lyapunov stability theory and LaSalle’s invariance principle. Another advantage was
found from the analysis of their numerical performance: their exponential decay feature contributes to the rapid decrease of the control input,
thus reducing their consumption of energy.
(D) An analysis of the controllers discovered by the GP in the article ‘Synthetic-analytic behavior-based control framework: Constraining
velocity in tracking for nonholonomic wheeled mobile robots’, led us to a proposal of a family of controllers for first order dynamical systems.
The results were published in the IET Control Theory & Applications journal. This is a leading journal devoted to control systems that covers
new theoretical results, and the applications of new and established control methods. Hence, our results have been recognized by the control
theory community for their novelty and as theoretically demonstrated results.
(F) The performance of the proposed family of nonlinear controllers is comparable against results from state-of-the-art proposals derived
solely from Control Theory or Machine Learning techniques. The integration of the Control Theory approach with the Genetic Programming
paradigm presented in ‘Synthetic-analytic behavior-based control framework: Constraining velocity in tracking for nonholonomic wheeled
mobile robots’ generated 9113 synthesized suitable nonlinear controllers for the addressed control problem. This is a major advantage with
respect to the traditional manual design of controllers since, typically, the development of a single controller, by experienced researchers,
for a particular problem can take several days or weeks. In addition, the integration with the Control Theory framework allows the derivation
of a global stability proof for the closed-loop dynamics in first-order dynamical systems using the Lyapunov criteria. The Lyapunov criteria
is one of the cornerstones of the Control Theory approach, its fulfillment by our proposed family of controllers, derived from those found by
the GP, guarantees its acceptance within this community. The work in ‘Family of Controllers based on Sector Nonlinear Functions: An Application
for First Order Dynamical Systems’ showed through numerical analysis that the proposed nonlinear controllers offer comparable performance to
that of the established P and PI controllers, demanding less energy from the actuators with a shorter amount of time under saturation conditions.
Such a set of controllers was derived from a particular class of sector nonlinear functions that stand out from the controllers found by the GP
in ‘Synthetic-analytic behavior-based control framework: Constraining velocity in tracking for nonholonomic wheeled mobile robots’.
7. A FULL CITATION OF THE PAPER (THAT IS, AUTHOR NAMES; PUBLICATION DATE; NAME OF JOURNAL, CONFERENCE, TECHNICAL REPORT, THESIS, BOOK, OR
BOOK CHAPTER; NAME OF EDITORS, IF APPLICABLE, OF THE JOURNAL OR EDITED BOOK; PUBLISHER NAME; PUBLISHER CITY; PAGE NUMBERS, IF APPLICABLE);
* Marlen Meza-Sánchez, Eddie Clemente, M.C. Rodríguez-Liñán, Gustavo Olague, “Synthetic-analytic behavior-based control framework: Constraining
velocity in tracking for nonholonomic wheeled mobile robots”, Information Sciences, Volume 501, 2019, Pages 436-459, ISSN 0020-0255,
DOI: 10.1016/j.ins.2019.06.025
http://www.sciencedirect.com/science/article/pii/S0020025519305602
* Marlen Meza-Sánchez, M.C. Rodríguez-Liñán, Eddie Clemente, “Family of Controllers based on Sector Nonlinear Functions: An Application for First
Order Dynamical Systems”, IET Control Theory & Applications, In press, 2020, Print ISSN 1751-8644, Online ISSN 1751-8652 DOI: iet-cta.2019.0680
https://digital-library.theiet.org/content/journals/10.1049/iet-cta.2019.0680
8. A STATEMENT EITHER THAT "ANY PRIZE MONEY, IF ANY, IS TO BE DIVIDED EQUALLY AMONG THE CO-AUTHORS" OR A SPECIFIC PERCENTAGE BREAKDOWN AS TO HOW
THE PRIZE MONEY, IF ANY, IS TO BE DIVIDED AMONG THE CO-AUTHORS;
Any prize money, if any, is to be divided equally among the co-authors Marlen Meza-Sánchez, M.C. Rodríguez-Liñán, Eddie Clemente
9. A STATEMENT STATING WHY THE AUTHORS EXPECT THAT THEIR ENTRY WOULD BE THE "BEST",
We believe that our work has several merits and contributions to the state-of-the-art,
1) Even when the solutions discovered by the GP in the article ‘Synthetic-analytic behavior-based control framework: Constraining velocity in
tracking for nonholonomic wheeled mobile robots’ are for the kinematic model of nonholonomic wheeled mobile robots, they have been proven to be
a general control solution for first-order dynamical systems and, additionally, a whole family of controllers was proposed.
2) The identified sector nonlinear functions allowed us to propose a large class of nonlinear controllers. This is a major advantage against most
human control design processes within the Control Theory community, where controllers can take weeks even for the most experienced researchers.
Moreover, these controllers are designed one at a time.
3) The analytic nature of the solutions found by the GP allows for a simple and attractive implementation of the control law. The computational
load for any embedded system or experimental platform is small since the solutions rely on the inherent properties of the particular class of sector
nonlinear functions identified by the GP. It only requires the straightforward computation of the functions with respect to error between the output
of the system and the desired behavior. They are also general solutions for output control problems in first-order dynamical systems. This means that,
in contrast with many soft computing techniques, they do not depend on initial conditions of the system (from where they depart), nor on the initial
error with respect to the desired behavior. Notice that the importance of first-order dynamical systems relies on their usage to model a broad class
of systems, appearing in many research fields. Just to mention a few, it can be used to model phenomena in physics, motion in robotics, dynamics of
electronic and electrical circuits, pharmacokinetics of drugs, nodes in a network, chemical reactions, among others.
4) The nonlinear sector functions found by the GP allows for the construction of controllers that offer very similar performance to that of the P
and PI controllers. The classical P and PI are linear controllers belonging to the well-known PID control family. PID control, first developed in
1911 by Elmer Sperry, is extensively used in the industry, and largely studied by the control theory community. Together with its variants, PID control
is arguably one of the most important developments in control theory. Moreover, while the family of PID controllers is linear by nature, they are
also sectorial functions that belong to the same sector as the ones that we propose. Thus, the classical PID-like controllers could be seen as a linear
case of the proposed SNFs controllers. However, the nonlinear nature of our controllers, characterized by an exponential decay feature, contributes to
a rapid decrease of the control input, thus reducing their consumption of energy.
5) The most consuming task in the development of controllers under the Control Theory approach is the stability proof of the resulting system dynamics
with the designed control input (i.e., the closed-loop dynamics). The lack of this proof is the main and most ancient argument of the Control Theory
community against accepting solutions to control problems presented by other communities. The identified class of nonlinear functions obtained by the
GP in ‘Synthetic-analytic behavior-based control framework: Constraining velocity in tracking for nonholonomic wheeled mobile robots’ have passive
properties that allow for the construction of a global proof of stability of the closed-loop dynamics using the Lyapunov stability criteria and LaSalle’s
invariance principle. This is reflected in the fact that our work entitled ‘Family of Controllers based on Sector Nonlinear Functions: An Application for
First Order Dynamical Systems’ has been published in a leading journal devoted to control systems. Its recognition has gone beyond the implementation of
evolutionary computation to solve control problems.
6) The discovered solutions are nonlinear controllers with global stability proof. While the Control Theory community has the Classic approach for
the analysis of linear systems, the nature of our controllers is nonlinear, hence their closed-loop dynamics are also nonlinear, and the Modern Control
approach has been used. It is important to point out that even when the Lyapunov stability criteria is well established, there is not a recipe for the
construction of the Lyapunov candidate functions used to apply this criteria. This means that the GP was able to find continuous functions sharing
interesting properties which help in the development of the stability proof. And global, nonetheless.
At this time, the notion that this idea can be exploited for systems of higher degree is being explored. The use of this particular class of Sector
Nonlinear Functions found by the GP for modeling and compensation of nonlinearities appearing in physical systems modeled by ordinary differential
equations is also being considered. One of our reviewers pointed out the idea that they could also be applied in first-order dynamical systems with
constant delays. The numerical results presented in our paper considers this special case without developing a stability proof. However, their
performance supports the belief that our proposal could have a bigger impact in the subject. We are currently exploring the extensive area of
opportunity that has opened up from our initial work, and are confident of the possibilities, and the impact that this contribution can bring to
the community.
10. AN INDICATION OF THE GENERAL TYPE OF GENETIC OR EVOLUTIONARY COMPUTATION USED, SUCH AS GA (GENETIC ALGORITHMS), GP (GENETIC PROGRAMMING),
ES (EVOLUTION STRATEGIES), EP (EVOLUTIONARY PROGRAMMING), LCS (LEARNING CLASSIFIER SYSTEMS), GE (GRAMMATICAL EVOLUTION), GEP (GENE EXPRESSION PROGRAMMING),
DE (DIFFERENTIAL EVOLUTION), ETC.
GP (Genetic Programming)
11. THE DATE OF PUBLICATION OF EACH PAPER. IF THE DATE OF PUBLICATION IS NOT ON OR BEFORE THE DEADLINE FOR SUBMISSION, BUT INSTEAD, THE PAPER HAS
BEEN UNCONDITIONALLY ACCEPTED FOR PUBLICATION AND IS “IN PRESS” BY THE DEADLINE FOR THIS COMPETITION, THE ENTRY MUST INCLUDE A COPY OF THE DOCUMENTATION
ESTABLISHING THAT THE PAPER MEETS THE "IN PRESS" REQUIREMENT.
08 June 2019 - Synthetic-analytic behavior-based control framework: Constraining velocity in tracking for nonholonomic wheeled mobile robots
02 February 2020 - A Family of Controllers based on Sector Nonlinear Functions: An Application for First Order Dynamical Systems