Robotran-YARP Interface: A Framework for Real-Time Controller Developments Based on Multibody Dynamics Simulations

Author(s):  
Timothée Habra ◽  
Houman Dallali ◽  
Alberto Cardellino ◽  
Lorenzo Natale ◽  
Nikolaos Tsagarakis ◽  
...  
2020 ◽  
Author(s):  
Martin Servin ◽  
Tomas Berglund ◽  
Samuel Nystedt

Abstract A multiscale model for real-time simulation of terrain dynamics is explored. To represent the dynamics on different scales the model combines the description of soil as a continuous solid, as distinct particles and as rigid multibodies. The models are dynamically coupled to each other and to the earthmoving equipment. Agitated soil is represented by a hybrid of contacting particles and continuum solid, with the moving equipment and resting soil as geometric boundaries. Each zone of active soil is aggregated into distinct bodies, with the proper mass, momentum and frictional-cohesive properties, which constrain the equipment's multibody dynamics. The particle model parameters are pre-calibrated to the bulk mechanical parameters for a wide range of different soils. The result is a computationally efficient model for earthmoving operations that resolve the motion of the soil, using a fast iterative solver, and provide realistic forces and dynamic for the equipment, using a direct solver for high numerical precision. Numerical simulations of excavation and bulldozing operations are performed to validate model and measure the computational performance. Reference data is produced using coupled discrete element and multibody dynamics simulations at relatively high resolution. The digging resistance and soil displacements with the real-time multiscale model agree with the reference model up to 10-25%, and run more than three orders in magnitude faster.


Author(s):  
Martin Servin ◽  
Tomas Berglund ◽  
Samuel Nystedt

AbstractA multiscale model for real-time simulation of terrain dynamics is explored. To represent the dynamics on different scales the model combines the description of soil as a continuous solid, as distinct particles and as rigid multibodies. The models are dynamically coupled to each other and to the earthmoving equipment. Agitated soil is represented by a hybrid of contacting particles and continuum solid, with the moving equipment and resting soil as geometric boundaries. Each zone of active soil is aggregated into distinct bodies, with the proper mass, momentum and frictional-cohesive properties, which constrain the equipment’s multibody dynamics. The particle model parameters are pre-calibrated to the bulk mechanical parameters for a wide range of different soils. The result is a computationally efficient model for earthmoving operations that resolve the motion of the soil, using a fast iterative solver, and provide realistic forces and dynamic for the equipment, using a direct solver for high numerical precision. Numerical simulations of excavation and bulldozing operations are performed to test the model and measure the computational performance. Reference data is produced using coupled discrete element and multibody dynamics simulations at relatively high resolution. The digging resistance and soil displacements with the real-time multiscale model agree with the reference model up to 10–25%, and run more than three orders of magnitude faster.


2019 ◽  
Vol 7 (11) ◽  
pp. 3286-3293 ◽  
Author(s):  
Baoxi Feng ◽  
Zhen Xu ◽  
Jiayu Wang ◽  
Fei Feng ◽  
Lin Wang ◽  
...  

A self-assembly mechanism is demonstrated for the formation of polymer nanofilms based on real-time visualization and molecular dynamics simulations.


Author(s):  
Rudranarayan M. Mukherjee ◽  
Kurt S. Anderson

This is the first paper in a series of two papers on using multibody dynamics algorithms and methods for coarse-grained molecular dynamics simulations. This paper presents the underlying framework for multi-scale modelling of biomolecules and polymers. In this framework, the system to be simulated is sub-structured into a hierarchy of multi-resolution models that are simulated using efficient multibody dynamics algorithms. The algorithms work in a unified framework, enabling efficient multi-scale (or multi-resolution) simulations. A discussion of the hierarchy of models with different resolutions along with the salient features of the appropriate multibody dynamics algorithms used for simulating them is presented. The unified scheme and the qualitative advantages of the method are discussed. Important implementation details such as boundary conditions, temporal integration schemes, interaction force field calculations and solvent models are also presented. In the next paper applications and results are discussed.


Author(s):  
William Prescott

This paper will investigate the use of large scale multibody dynamics (MBD) models for real-time vehicle simulation. Current state of the art in the real-time solution of vehicle uses 15 degree of freedom models, but there is a need for higher-fidelity systems. To increase the fidelity of models uses this paper will propose the use of the following techniques: implicit integration, parallel processing and co-simulation in a real-time environment.


2006 ◽  
Vol 65 (12) ◽  
pp. 2091-2111 ◽  
Author(s):  
D. Dopico ◽  
U. Lugris ◽  
M. Gonzalez ◽  
J. Cuadrado
Keyword(s):  

Author(s):  
Tamer M. Wasfy ◽  
Hatem M. Wasfy ◽  
Jeanne M. Peters

A flexible multibody dynamics explicit time-integration parallel solver suitable for real-time virtual-reality applications is presented. The hierarchical “scene-graph” representation of the model used for display and user-interaction with the model is also used in the solver. The multibody system includes rigid bodies, flexible bodies, joints, frictional contact constraints, actuators and prescribed motion constraints. The rigid bodies rotational equations of motion are written in a body-fixed frame with the total rigid body rotation matrix updated each time step using incremental rotations. Flexible bodies are modeled using total-Lagrangian spring, truss, beam and hexahedral finite elements. The motion of the elements is referred to a global inertial Cartesian reference frame. A penalty technique is used to impose joint/contact constraints. An asperity-based friction model is used to model joint/contact friction. A bounding box binary tree contact search algorithm is used to allow fast contact detection between finite elements and other elements as well as general triangular/quadrilateral rigid-body surfaces. The real-time solver is used to model virtual-reality based experiments (including mass-spring systems, pendulums, pulley-rope-mass systems, billiards, air-hockey and a solar system) for a freshman university physics e-learning course.


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