Multibody dynamics simulation is widely used for prototyping and testing controllers. However, the transfer of controllers initially developed in simulation to real mechatronics platforms requires updating the code in...
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ISBN:
(纸本)9783319306148;9783319306124
Multibody dynamics simulation is widely used for prototyping and testing controllers. However, the transfer of controllers initially developed in simulation to real mechatronics platforms requires updating the code in order to interface with physical sensors and actuators. Due to this strong coupling with specific hardware, the controller re-usability is often severely compromised. In the present contribution, we solve this issue by adding a middleware between the controller and the controlled platform (either real or simulated). This framework decouples the controller from the hardware, allows fast controller developments and eases collaborations on large scale projects. Moreover, it offers the possibility to simultaneously control the real and the simulated robot from a unique controller. This paper presents the interface of the Robotran dynamic simulator with the YARP middleware. Robotran leverages symbolic generation of the multibody equations to provide fast and accurate simulations of multibody systems. The speed and accuracy of Robotran make it possible to test real-time controllers in a realistic simulation environment. This framework is illustrated with applications using the COMAN and WALK-MAN humanoid robots.
This chapter provides an initial investigation into using the Graphics Processing Unit (GPU) (or similar hardware) to execute the Divide-and-Conquer Algorithm (DCA), which forms and solves the equations-of-motion for ...
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ISBN:
(纸本)9783319306148;9783319306124
This chapter provides an initial investigation into using the Graphics Processing Unit (GPU) (or similar hardware) to execute the Divide-and-Conquer Algorithm (DCA), which forms and solves the equations-of-motion for articulated multibody systems. The computational time required to form and solve the equations-of-motion of a simple n-length pendulum using the GPU is compared with a standard serial CPU implementation, a rudimentary parallelization on the CPU using OpenMP, and some combinations of the CPU and the GPU. The hybrid version uses the GPU for a select number of levels in the recursive sweeps and uses an OpenMP parallelization on a multi-core CPU for the remaining levels of recursion. The results demonstrate a significant performance increase when the GPU is used despite recursive algorithms being ill-suited to hardware designed for Single Instruction Multi-Data (SIMD). This is largely due to the tree-type structure of recursive processes, with half of the required operations being contained in the first level of recursion for a binary tree.
In the present study, we propose an analytical model with a multibody system considering three-dimensional wheel/rail contact geometry and ballasted track characteristics. Suppression of contact force fluctuation betw...
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ISBN:
(纸本)9783319306148;9783319306124
In the present study, we propose an analytical model with a multibody system considering three-dimensional wheel/rail contact geometry and ballasted track characteristics. Suppression of contact force fluctuation between the wheel and rail is desirable from the viewpoint of ensuring running safety, track maintenance, ride comfort, and minimizing the impact of factors such as noise on the surrounding environment. In the present paper, we investigate the effects of the support characteristics of ballasted track on the interaction between vehicles and tracks. Numerical simulations and experiments are carried out for railway vehicle motion under a wide range of ballasted track rigidities. Using the proposed numerical model, we obtain analysis results that are consistent with experimental results under two different track conditions: one simulating ordinary ballasted track characteristics and one that provides sufficient space between sleepers and ballasts. The proposed numerical simulation can accurately analyze vehicle motion running over ballasted track by considering the interaction between the vehicle and the track.
A new index reduction approach is developed for the inverse dynamics simulation of underactuated mechanical systems. The underlying equations of motion contain both holonomic and servo constraints. The proposed method...
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ISBN:
(纸本)9783319306148;9783319306124
A new index reduction approach is developed for the inverse dynamics simulation of underactuated mechanical systems. The underlying equations of motion contain both holonomic and servo constraints. The proposed method is applied to a very general and versatile formulation of cranes. The numerical results demonstrate the functional efficiency of the method.
This volume contains the best papers presented at the 2nd ECCOMAS International Conference on Multiscale Computations for Solids and Fluids, held June 10-12, 2015. Topics dealt with include multiscale strategy for eff...
ISBN:
(数字)9783319279961
ISBN:
(纸本)9783319279947
This volume contains the best papers presented at the 2nd ECCOMAS International Conference on Multiscale Computations for Solids and Fluids, held June 10-12, 2015. Topics dealt with include multiscale strategy for efficient development of scientific software for large-scale computations, coupled probability-nonlinear-mechanics problems and solution methods, and modern mathematical and computational setting for multi-phase flows and fluid-structure interaction. The papers consist of contributions by six experts who taught short courses prior to the conference, along with several selected articles from other participants dealing with complementary issues,covering both solid mechanics and applied mathematics.
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