Interactive dynamics

Witkin, Andrew; Gleicher, Michael; Welch, William

doi:10.1145/91394.91400

Cited by 88 publications

(43 citation statements)

References 11 publications

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“…Lagrange multiplier method [17], [19], [20] is adopted 1) to construct equations of motion for each state and 2) to simultaneously monitor vertical components of the ground reaction forces and the height of each foot, in order to detect transition between each dynamic state.…”

Section: B Hybrid Dynamics and Lagrange Multiplier Methodsmentioning

confidence: 99%

On the dynamics of a quadruped robot model with impedance control: Self-stabilizing high speed trot-running and period-doubling bifurcations

Lee

Hyun

Ahn

et al. 2014

2014 IEEE/RSJ International Conference on Intelligent Robots and Systems

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Abstract-The MIT Cheetah demonstrated a stable 6 m/s trot gait in the sagittal plane utilizing the self-stable characteristics of locomotion. This paper presents a numerical analysis of the behavior of a quadruped robot model with the proposed controller. We first demonstrate the existence of periodic trot gaits at various speeds and examine local orbital stability of each trajectory using Poincarè map analysis. Beyond the local stability, we additionally demonstrate the stability of the model against large initial perturbations. Stability of trot gaits at a wide range of speed enables gradual acceleration demonstrated in this paper and a real machine. This simulation study also suggests the upper limit of the command speed that ensures stable steady-state running. As we increase the command speed, we observe series of period-doubling bifurcations, which suggests presence of chaotic dynamics beyond a certain level of command speed. Extension of this simulation analysis will provide useful guidelines for searching control parameters to further improve the system performance.

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Section: B Hybrid Dynamics and Lagrange Multiplier Methodsmentioning

confidence: 99%

On the dynamics of a quadruped robot model with impedance control: Self-stabilizing high speed trot-running and period-doubling bifurcations

Lee

Hyun

Ahn

et al. 2014

2014 IEEE/RSJ International Conference on Intelligent Robots and Systems

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show abstract

“…Penalty based methods are easy to implement and computationally inexpensive, however they are characterized with problems caused by very high spring stiffness leading to stiff equations which are numerically intractable [47]. The impulse based methods [48][49][50] simulate interactions among objects using collision impulses.…”

Section: Physics-based Modelingmentioning

confidence: 99%

Virtual reality for assembly methods prototyping: a review

2010

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Assembly planning and evaluation is an important component of the product design process in which details about how parts of a new product will be put together are formalized. A well designed assembly process should take into account various factors such as optimum assembly time and sequence, tooling and fixture requirements, ergonomics, operator safety, and accessibility, among others. Existing computer-based tools to support virtual assembly either concentrate solely on representation of the geometry of parts and fixtures and evaluation of clearances and tolerances or use simulated human mannequins to approximate human interaction in the assembly process. Virtual reality technology has the potential to support integration of natural human motions into the computer aided assembly planning environment (Ritchie et al. in Proc I MECH E Part B J Eng 213(5): [461][462][463][464][465][466][467][468][469][470][471][472][473][474] 1999). This would allow evaluations of an assembler's ability to manipulate and assemble parts and result in reduced time and cost for product design. This paper provides a review of the research in virtual assembly and categorizes the different approaches. Finally, critical requirements and directions for future research are presented. Disciplines Computer-Aided Engineering and Design | Graphics and Human Computer InterfacesComments This is a manuscript of an article from Virtual Reality 15 (2011) AbstractAssembly planning and evaluation is an important component of the product design process in which details about how parts of a new product will be put together are formalized. A well designed assembly process should take into account various factors such as optimum assembly time and sequence, tooling and fixture requirements, ergonomics, operator safety, and accessibility, among others.Existing computer-based tools to support virtual assembly either concentrate solely on representation of the geometry of parts and fixtures and evaluation of clearances and tolerances or use simulated human mannequins to approximate human interaction in the assembly process.Virtual reality (VR) technology has the potential to support integration of natural human motions into the computer aided assembly planning environment (CAAP) [1]. This would allow evaluations of an assembler's ability to manipulate and assemble parts and result in reduced time and cost for product design. This paper provides a review of the research in virtual assembly and categorizes the different approaches Finally, critical requirements and directions for future research are presented.

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“…The particle-based model technique is based on a discretization of an object volume into a set of point masses (particles) connected by links (often modelled as springs and dampers, i.e., attracting and repelling forces) [Witkin, 1995]. Springs and dampers model the interaction laws among the particles determining the dynamic behavior of the object material.…”

Section: Issuesmentioning

confidence: 99%

From Solids to Particle-Based Models

Bordegoni

Cilloni

Angelis

2002

From Geometric Modeling to Shape Modeling

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This paper addresses the issue of generating mathematical models of flexible objects suitable for NRM simulation. These models should contain proper information not only on the objects geometry, but also on the physical properties 'Of the material they are made of. This paper mainly addresses the geometrical issues of generating particle-based models of flexible objects, but basic methods for determining the material characterization in some special cases are also discussed. The ongoing research work performed by the authors and the related results are presented. Keywords:Non Rigid Materials simulation, particle models IntroductionThere is an increasing market demand for the simulation of non-rigid objects. In industrial sectors where traditionally CAD systems are used (i.e., automotive, aeronautics, ... ) there are situations where the simulation of non-rigid parts is required and not available (for example; the simulation of wires, seats, etc.). There are industrial sectors where CAD systems are not used since they do not support modeling of non-rigid products (i.e., textile, fashion, food, ... ). Finally there are novel sectors like the medical area, where the simulation of non-rigid bodies would support and improve several critical tasks, like training of procedures and pre-op simulation.The simulation of objects behaviour requires the creation of a model. Traditional geometric modeling is a mature technology but is not appropriate for non-rigid objects simulation because the generated models lack the kind of information which is needed by a non-rigid material simulator. Current solid models mainly carry information on the geometrical and topological aspects of the model's "outside" (its boundary), plus optional information of the overall volume and mass, assuming the model is rigid and made of a homogeneous and isotropic material.

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Interactive dynamics

Cited by 88 publications

References 11 publications

On the dynamics of a quadruped robot model with impedance control: Self-stabilizing high speed trot-running and period-doubling bifurcations

On the dynamics of a quadruped robot model with impedance control: Self-stabilizing high speed trot-running and period-doubling bifurcations

Virtual reality for assembly methods prototyping: a review

From Solids to Particle-Based Models

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