Koditschek, Daniel E

Email Address
Acoustics, Dynamics, and Controls
Artificial Intelligence and Robotics
Control Theory
Controls and Control Theory
Dynamic Systems
Electro-Mechanical Systems
Ordinary Differential Equations and Applied Dynamics
Systems and Integrative Engineering
Research Projects
Organizational Units
Faculty Member
I am a robotics researcher with interests in applications of dynamical systems to intelligent machines using bioinspired designs.
Research Interests

Search Results

Now showing 1 - 10 of 260
  • 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
    Universal Memory Architectures for Autonomous Machines
    (2016-01-01) Guralnik, Dan P; Koditschek, Daniel E
    We propose a self-organizing memory architecture (UMA) for perceptual experience provably capable of supporting autonomous learning and goal-directed problem solving in the absence of any prior information about the agent’s environment. The architecture is simple enough to ensure (1) a quadratic bound (in the number of available sensors) on space requirements, and (2) a quadratic bound on the time-complexity of the update-execute cycle. At the same time, it is sufficiently complex to provide the agent with an internal representation which is (3) minimal among all representations which account for every sensory equivalence class consistent with the agent’s belief state; (4) capable, in principle, of recovering a topological model of the problem space; and (5) learnable with arbitrary precision through a random application of the available actions. These provable properties — both the trainability and the operational efficacy of an effectively trained memory structure — exploit a duality between weak poc sets — a symbolic (discrete) representation of subset nesting relations — and non-positively curved cubical complexes, whose rich convexity theory underlies the planning cycle of the proposed architecture.
  • Publication
    RHex: A Simple and Highly Mobile Hexapod Robot
    (2001-07-01) Saranli, Uluc; Buehler, Martin; Koditschek, Daniel E
    In this paper, the authors describe the design and control of RHex, a power autonomous, untethered, compliant-legged hexapod robot. RHex has only six actuators—one motor located at each hip—achieving mechanical simplicity that promotes reliable and robust operation in real-world tasks. Empirically stable and highly maneuverable locomotion arises from a very simple clock-driven, openloop tripod gait. The legs rotate full circle, thereby preventing the common problem of toe stubbing in the protraction (swing) phase. An extensive suite of experimental results documents the robot’s significant “intrinsic mobility”—the traversal of rugged, broken, and obstacle-ridden ground without any terrain sensing or actively controlled adaptation. RHex achieves fast and robust forward locomotion traveling at speeds up to one body length per second and traversing height variations well exceeding its body clearance.