Efficient simulation of Mechanism Kinematics Using Bond Graphs.

This paper presents a methodology for obtaining the equations corresponding to a mechanism that are necessary for carrying out a kinematic simulation. A simulation of this kind means obtaining the coordinates dependent on the system according to the movements imposed by the degrees of freedom. Unlike a dynamic simulation, where the set of elements moves according to the different external forces existing, in kinematic simulation the movement of the whole set depends exclusively on imposing movement on one or more of the bodies according to the degrees of freedom initially possessed by the mechanism. After presenting an analysis of how to obtain the necessary equations for several simple systems, this methodology is applied to the particular case of a front-loader, where in order to move and tilt the bucket, various closed mechanisms are integrated

Formula manipulation in the bond graph modelling and simulation of large mechanical systems

A multibond graph element for a general single moving body is derived. A multibody system can easily be described as an interconnection of these elements. 3-D mechanical systems usually contain dependent inertias having both differential and integral causality. A method is described for the transformation of inertias with differential causality to an integral form, using formula manipulation. The program also helps to find experimentally the optimal choice for the generalized coordinates. The resulting explicit differential equation may be solved using a standard integration routine or simulation program

A Biomechanical Model for the Development of Myoelectric Hand Prosthesis Control Systems

Advanced myoelectric hand prostheses aim to reproduce as much of the human hand's functionality as possible. Development of the control system of such a prosthesis is strongly connected to its mechanical design; the control system requires accurate information on the prosthesis' structure and the surrounding environment, which can make development difficult without a finalized mechanical prototype. This paper presents a new framework for the development of electromyographic hand control systems, consisting of a prosthesis model based on the biomechanical structure of the human hand. The model's dynamic structure uses an ellipsoidal representation of the phalanges. Other features include underactuation in the fingers and thumb modeled with bond graphs, and a viscoelastic contact model. The model's functions are demonstrated by the execution of lateral and tripod grasps, and evaluated with regard to joint dynamics and applied forces. Finally, additions are suggested with which this model can be of use in mechanical design and patient training as well

Teaching kinematics and dynamics of multibody mechanical systems using the object oriented language modelica

A new modeling language, called Modelica, for physical modeling is being developed in an international effort. The main objective is to make it easy to exchange models and model libraries for different domains, such as, mechanical, pneumatics, electrical, hydraulics, and others. The design approach builds on non-causal modeling with true ordinary differential and algebraic equations and the use of object-oriented constructs stemming from modern software development, (hierarchy, encapsulation) to facilitate reuse of models and model parts. This paper gives an overview of the use of the object oriented language Modelica with the mechanical Multibody Library to model and simulate three-dimensional mechanical systems

SIMBIO-M 2014, SIMulation technologies in the fields of BIO-Sciences and Multiphysics: BioMechanics, BioMaterials and BioMedicine, Marseille, France, june 2014

Proceedings de la 3ème édition de la conférence internationale Simbio-M (2014). Organisée conjointement par l'IFSTTAR, Aix-Marseille Université, l'université de Coventry et CADLM, cette conférence se concentre sur les progrès des technologies de simulation dans les domaines des sciences du vivant et multiphysiques: Biomécanique, Biomatériaux et Biomédical. L'objectif de cette conférence est de partager et d'explorer les résultats dans les techniques d'analyse numérique et les outils de modélisation mathématique. Cette approche numérique permet des études prévisionnelles ou exploratoires dans les différents domaines des biosciences

Modelling and Simulation of a Manipulator with Stable Viscoelastic Grasping Incorporating Friction

Design, dynamics and control of a humanoid robotic hand based on anthropological dimensions, with joint friction, is modelled, simulated and analysed in this paper by using computer aided design and multibody dynamic simulation. Combined joint friction model is incorporated in the joints. Experimental values of coefficient of friction of grease lubricated sliding contacts representative of manipulator joints are presented. Human fingers deform to the shape of the grasped object (enveloping grasp) at the area of interaction. A mass-spring-damper model of the grasp is developed. The interaction of the viscoelastic gripper of the arm with objects is analysed by using Bond Graph modelling method. Simulations were conducted for several material parameters. These results of the simulation are then used to develop a prototype of the proposed gripper. Bond graph model is experimentally validated by using the prototype. The gripper is used to successfully transport soft and fragile objects. This paper provides information on optimisation of friction and its inclusion in both dynamic modelling and simulation to enhance mechanical efficiency

Reduced simulation´s model of a wheel loader by using the Bond Graph technique to use in training simulators

This paper presents a model developed for simulating earth moving machines like wheel loaders. The developed model is used for real time simulation and is included in a full machinery simulator designated for the training. The model includes a mechanical model of the chassis, axles, suspension systems, hydraulic actuators and mechanical models of the arms. All the models have been simulated using Bond Graph elements (Karnopp et al. 1990). The complete model has been developed as a modular system, using sub-models of each of the above-mentioned components. This approach helps to minimize both the number and complexity of the system equations obtained from the overall model. Some simulation examples and results are also included

Approaches and possible improvements in the area of multibody dynamics modeling

A wide ranging look is taken at issues involved in the dynamic modeling of complex, multibodied orbiting space systems. Capabilities and limitations of two major codes (DISCOS, TREETOPS) are assessed and possible extensions to the CONTOPS software are outlined. In addition, recommendations are made concerning the direction future development should take in order to achieve higher fidelity, more computationally efficient multibody software solutions