Kod*Lab

We are interested in the application of dynamical systems theory to the invention and construction of intelligent machines and systems, with a particular focus on biologically inspired robotics. Many of us have worked in robotics with emphasis on dynamical dexterity and the management of kinetic energy in designing machines capable of performing useful work on their bodies and environments. Others of us have worked on more abstract problems of control and coordination with the object of developing new methods of design and analysis toward the construction of such machines.

For more information: Kod*Lab

 

 

 

 

School of Engineering and Applied Science

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  • Publication
    Analysis of a Simplified Hopping Robot
    (1988-05-01) Koditschek, Daniel E; Buehler, Martin
    We offer some preliminary analytical results concerning simplified models of Raibert’s hopper. We represent the task of achieving a recurring hopping height for an actuated “ball” robot as a stability problem in the setting of a nonlinear discrete dynamical system. We model the properties of Raibert’s control scheme in a simplified fashion, and provide conditions under which the procedure results in closed loop dynamics possessed of a globally attracting fixed point - the formal rendering of what we intuitively mean by a “correct” strategy. The motivation for this work is the hope that it will facilitate the development of general design principles for “dynamically dexterous” robots. For more information: Kod*Lab
  • Publication
    Analysis of A Simplified Hopping Robot
    (1991-12-01) Koditschek, Daniel E; Buehler, Martin
    This article offers some analytical results concerning simplified models of Raibert's hopper. We represent the task of achieving a recurring hopping height for an actuated "ball" robot as a stability problem in a nonlinear discrete dynamical control system. We model the properties of Raibert's control scheme in a simplified fashion and argue that his strategy leads to closed-loop dynamics governed by a well-known class of functions, the unimodal maps. The rich mathematical literature on this subject greatly advances our ability to determine the presence of an essentially globally attracting fixed point-the formal rendering of what we intuitively mean by a "correct" strategy. The motivation for this work is the hope that it will facilitate the development of general design principles for "dynamically dexterous" robots.
  • Publication
    Integrating a Hierarchy of Simulation Tools for Legged Robot Locomotion
    (2008-09-01) Slatton, Andrew; Ding, Yang; Umbanhowar, P B; Goldman, Daniel; Haynes, Galen C; Komsuoglu, Haldun; Koditschek, Daniel E; Cohen, Daniel
    We are interested in the development of a variety of legged robot platforms intended for operation in unstructured outdoor terrain. In such settings, the traditions of rational engineering design, driven by analytically informed and computationally assisted studies of robot-environment models, remain ineffective due to the complexity of both the robot designs and the terrain in which they must operate. Instead, empirical trial and error often drives the necessary incremental and iterative design process, hence the development of such robots remains expensive both in time and cost, and is often closely dependent upon the substrate properties of the locomotion terrain. This paper describes a series of concurrent but increasingly coordinated software development efforts that aim to diminish the gap between easily interfaced and physically sound computational models of a real robot’s operation in a complex natural environment. We describe a robot simulation environment in which simple robot modifications can be easily prototyped along and “played” into phenomenological models of contact mechanics. We particularly focus on the daunting but practically compelling example of robot feet interacting granular media, such as gravel or sand, offering a brief report of our progress in deriving and importing physically accurate but computationally tractable phenomenological substrate models into the robot execution simulation environment. With a goal of integration for future robot prototyping simulations, we review the prospects for diminishing the gap between the integrated computational models and the needs of physical platform development.
  • Publication
    Self-Stability Mechanisms for Sensor-Cheap Legged Locomotion
    (2002-01-01) Koditschek, Daniel E; Altendorfer, Richard; Ghigliazza, Raffaele M; Holmes, Philip
    It is now well established that running animals’ mass centers exhibit the characteristics of a Spring Loaded Inverted Pendulum (SLIP) in the sagittal plane (Blickhan and Full, 1993). What control policy accomplishes this collapse of dimension by which animals solve the “degrees of freedom problem” (Bernstein, 1967)? How valuable might this policy be to gait control in legged robots?
  • Publication
    The Geometry of a Robot Programming Language
    (1995) Koditschek, Daniel E
    This paper explores the problem of building robot navigation plans via scalar valued functions in the face of incomplete information about the configuration space such as might be available from onboard sensors. It seems as though syntactical aspects of navigation function construction may play an important role. This problem provides an important concrete instance of the need for intelligent control. For more information: Kod*Lab
  • Publication
    Robot Control: Theoretical Foundations and Recent Trends
    (1986-07-31) Koditschek, Daniel E
  • Publication
    Cellular Decomposition and Classification of a Hybrid System
    (2014-01-01) Johnson, Aaron M; Koditschek, Daniel E
    Robots are often modeled as hybrid systems providing a consistent, formal account of the varied dynamics associated with the loss and gain of kinematic freedom as a machine impacts and breaks away from its environment.
  • Publication
    Technical Report on: Comparative Design, Scaling, and Control of Appendages for Inertial Reorientation
    (2016-09-01) Libby, Thomas; Johnson, Aaron; Full, R J; Koditschek, Daniel E.; Chang-Siu, Evan
  • Publication
    Dynamic Legged Mobility---an Overview
    (2009-05-20) Komsuoglu, Haldun
    Ability to translate to a goal position under the constrains imposed by complex environmental conditions is a key capability for biological and artificial systems alike. Over billions of years evolutionary processes have developed a wide range of solutions to address mobility needs in air, in water and on land. The efficacy of such biological locomotors is beyond the capabilities of engineering solutions that has been produced to this date. Nature has been and will surely remain to be a source of inspiration for engineers in their quest to bring "real mobility" to their creations. In recent years a new class of dynamic legged terrestrial robotic systems \cite{Autumn-Buehler-Cutkosky.SPIE2005,Raibert.Book1986,Raibert-Blankesport-Nelson.IFAC2008,Saranli-Buehler-Koditschek.IJRR2001} have been developed inspired by, but without mimicking, the examples from the Nature. The experimental work with these platforms over the past decade has led to an improved appreciation of legged locomotion. This paper is an overview of fundamental advantages dynamic legged locomotion offers over the classical wheeled and tracked approaches.
  • Publication
    Towards a method for obstacle porosity classification
    (2014-01-01) Roberts, Sonia F