Koditschek, Daniel E
Email Address
ORCID
Disciplines
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
Robotics
Systems and Integrative Engineering
Artificial Intelligence and Robotics
Control Theory
Controls and Control Theory
Dynamic Systems
Electro-Mechanical Systems
Ordinary Differential Equations and Applied Dynamics
Robotics
Systems and Integrative Engineering
relationships.isProjectOf
relationships.isOrgUnitOf
Position
Faculty Member
Introduction
I am a robotics researcher with interests in applications of dynamical systems to intelligent machines using bioinspired designs.
Research Interests
Collection
260 results
Search Results
Now showing 1 - 10 of 260
Publication The Application of Total Energy as a Lyapunov Function for Mechanical Control Systems(1989-02-14) Koditschek, Daniel EExamination of total energy shows that the global limit behavior of a dissipative mechanical system is essentially equivalent to that of its constituent gradient vector field. The class of “navigation functions” is introduced and shown to result in “almost global” asymptotic stability for closed loop mechanical control systems upon which a navigation function has been imposed as an artifical potential energy. Two examples from the engineering literature - satellite attitude tracking and robot obstacle avoidance - are provided to demonstrate the utility of these observations. For more information: Kod*LabPublication Brachiation on a Ladder with Irregular Intervals(1999-05-10) Nakanishi, Jun; Fukuda, Toshio; Koditschek, Daniel EWe have previously developed a brachiation controller that allows a two degree of freedom robot to swing from handhold to handhold on a horizontal ladder with evenly space rungs as well as swing up from a suspended posture using a "target dynamics" controller. In this paper, we extend this class of algorithms to handle the much more natural problem of locomotion over irregularly spaced handholds. Numerical simulations and laboratory experiments illustrate the effectiveness of this generalization.Publication The Stability of Second Order Quadratic Differential Equations(1982-08-01) Koditschek, Daniel E; Narendra, Kumpati JThis paper investigates the stability properties of second-order systems, x. = ƒ(x), where ƒ(x) contains either quadratic terms-system (1)-or linear and quadratic terms-system (2)-in x. The principal contributions are summarized in two theorems which give necessary and sufficient conditions for stability and asymptotic stability in the large of systems (1) and (2), respectively.Publication Cellular Decomposition and Classification of a Hybrid System(2014-01-01) Johnson, Aaron M; Koditschek, Daniel ERobots 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 Disturbance Detection, Identification, and Recovery by Gait Transition in Legged Robots(2010-10-01) Johnson, Aaron M; Haynes, Galen Clark; Koditschek, Daniel EWe present a framework for detecting, identifying, and recovering within stride from faults and other leg contact disturbances encountered by a walking hexapedal robot. Detection is achieved by means of a software contactevent sensor with no additional sensing hardware beyond the commercial actuators’ standard shaft encoders. A simple finite state machine identifies disturbances as due either to an expected ground contact, a missing ground contact indicating leg fault, or an unexpected “wall” contact. Recovery proceeds as necessary by means of a recently developed topological gait transition coordinator. We demonstrate the efficacy of this system by presenting preliminary data arising from two reactive behaviors — wall avoidance and leg-break recovery. We believe that extensions of this framework will enable reactive behaviors allowing the robot to function with guarded autonomy under widely varying terrain and self-health conditions.Publication Automatic assembly planning and control via potential functions(1991-11-03) Whitcomb, Louis L; Koditschek, Daniel EAn approach to the problem of automated assembly planning and control using artificial potential functions is described. A simple class of tasks, 2D sphere assemblies, is examined. A constructive theory for the planning and control of this class of tasks is presented. Computer simulations demonstrate that the approach may provide surprisingly good performance.Publication Toward a Vocabulary of Legged Leaping(2013-05-01) Johnson, Aaron M.; Koditschek, Daniel EAs dynamic robot behaviors become more capable and well understood, the need arises for a wide variety of equally capable and systematically applicable transitions between them. We use a hybrid systems framework to characterize the dynamic transitions of a planar “legged” rigid body from rest on level ground to a fully aerial state. The various contact conditions fit together to form a topologically regular structure, the “ground reaction complex”. The body’s actuated dynamics excite multifarious transitions between the cells of this complex, whose regular adjacency relations index naturally the resulting “leaps” (path sequences through the cells from rest to free flight). We exhibit on a RHex robot some of the most interesting “words” formed by these achievable path sequences, documenting unprecedented levels of performance and new application possibilities that illustrate the value of understanding and expressing this vocabulary systematically. For more information: Kod*LabPublication Stability Analysis of Legged Locomotion Models by Symmetry-Factored Return Maps(2004-10-01) Altendorfer, Richard; Koditschek, Daniel E; Holmes, PhilipWe present a new stability analysis for hybrid legged locomotion systems based on the “symmetric” factorization of return maps.We apply this analysis to two-degrees-of-freedom (2DoF) and threedegrees- of-freedom (3DoF) models of the spring loaded inverted pendulum (SLIP) with different leg recirculation strategies. Despite the non-integrability of the SLIP dynamics, we obtain a necessary condition for asymptotic stability (and a sufficient condition for instability) at a fixed point, formulated as an exact algebraic expression in the physical parameters. We use this expression to characterize analytically the sensory cost and stabilizing benefit of various feedback schemes previously proposed for the 2DoF SLIP model, posited as a low-dimensional representation of running.We apply the result as well to a 3DoF SLIP model that will be treated at greater length in a companion paper as a descriptive model for the robot RHex.Publication Exact robot navigation by means of potential functions: Some topological considerations(1987-03-01) Koditschek, Daniel EThe limits in global navigation capability of potential function based robot control algorithms are explored. Elementary tools of algebraic and differential topology are used to advance arguments suggesting the existence of potential functions over a bounded planar region with arbitrary fixed obstacles possessed of a unique local minimum. A class of such potential functions is constructed for certain cases of a planar disk region with an arbitrary number of smaller disks removed.Publication An Empirical Investigation of Legged Transitional Maneuvers Leveraging Raibert’s Scissor Algorithm(2015-12-01) Duperret, Jeff; Koditschek, Daniel EWe empirically investigate the implications of applying Raibert’s Scissor algorithm to the Spring Loaded Inverted Pendulum (SLIP) model in combination with other controllers to achieve transitional maneuvers. Specifically, we are interested in how the conjectured neutral stability of Raibert’s algorithm allows combined controllers to push the system’s operating point around the state space without needing to expend limited control affordance in overcoming its stability or compensating for its instability. We demonstrate 2 cases where this facilitates the construction of interesting transitional controllers on a physical robot. In the first we use the motors in stance to maximize the rate of change of the body energy; in the second we take advantage of the local environmental energy landscape to push the robot’s operating point to a higher or lower energy level without expending valuable motor affordance. We present data bearing on the energetic performance of these approaches in executing an accelerate-and-leap maneuver on a monopedal hopping robot affixed to a boom in comparison to the cost of anchoring the robot to the SLIP template. For more information: Kod*lab