Hybrid Modelling and Simulation of Rigid Bodies in Contact

Hybrid Modelling and Simulation of Rigid Bodies in Contact PDF Author: Reza Pedrami
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Book Description
Rigid body systems may undergo numerous types of dynamic interactions including collisions and continuous contact which considerably complicate systematic modelling and simulation of such problems. This thesis introduces a new modelling approach based on a hybrid system formulation to describe the dynamics of interacting rigid body systems. Interaction among physical objects occurs in two different forms: impulsive contact and continuous contact. Characteristics of impulsive and continuous contacts are different. Hence the modelling of each contact type requires the use of different approaches. While the impulse-modelling approach better simulates the impulsive contacts, our findings indicate that continues contact is much more accurately modeled using the sliding manifold method. The proposed hybrid system approach combines the impulse modelling method for collision interactions and the sliding manifold method to model the differential-algebraic equations associated with continuous contact interactions. Appropriate discrete states, events, reset maps, and threshold parameters that yield a hybrid automaton framework to describe interacting rigid body systems are developed. To illustrate the effectiveness of the proposed method a rolling ball simulation for a virtual reality system is presented.

Hybrid Modelling and Simulation of Rigid Bodies in Contact

Hybrid Modelling and Simulation of Rigid Bodies in Contact PDF Author: Reza Pedrami
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Book Description
Rigid body systems may undergo numerous types of dynamic interactions including collisions and continuous contact which considerably complicate systematic modelling and simulation of such problems. This thesis introduces a new modelling approach based on a hybrid system formulation to describe the dynamics of interacting rigid body systems. Interaction among physical objects occurs in two different forms: impulsive contact and continuous contact. Characteristics of impulsive and continuous contacts are different. Hence the modelling of each contact type requires the use of different approaches. While the impulse-modelling approach better simulates the impulsive contacts, our findings indicate that continues contact is much more accurately modeled using the sliding manifold method. The proposed hybrid system approach combines the impulse modelling method for collision interactions and the sliding manifold method to model the differential-algebraic equations associated with continuous contact interactions. Appropriate discrete states, events, reset maps, and threshold parameters that yield a hybrid automaton framework to describe interacting rigid body systems are developed. To illustrate the effectiveness of the proposed method a rolling ball simulation for a virtual reality system is presented.

Modeling of Rigid Body Contacts for Dynamic Simulation

Modeling of Rigid Body Contacts for Dynamic Simulation PDF Author: Peter R. Kraus
Publisher:
ISBN:
Category :
Languages : en
Pages : 326

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Book Description


Guide to Dynamic Simulations of Rigid Bodies and Particle Systems

Guide to Dynamic Simulations of Rigid Bodies and Particle Systems PDF Author: Murilo G. Coutinho
Publisher: Springer Science & Business Media
ISBN: 1447144163
Category : Computers
Languages : en
Pages : 402

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Book Description
This book introduces the techniques needed to produce realistic simulations and animations of particle and rigid-body systems. The text focuses on both the theoretical and practical aspects of developing and implementing physically based dynamic-simulation engines. Each chapter examines numerous algorithms, describing their design and analysis in an accessible manner, without sacrificing depth of coverage or mathematical rigor. Features: examines the problem of computing an hierarchical representation of the geometric description of each simulated object, as well as the simulated world; discusses the use of discrete and continuous collision detection to handle thin or fast-moving objects; describes the computational techniques needed for determining all impulsive and contact forces between bodies with multiple simultaneous collisions and contacts; presents techniques that can be used to dynamically simulate articulated rigid bodies; concludes each chapter with exercises.

Modelling and Simulation of Multibody Systems with Unilateral Contact

Modelling and Simulation of Multibody Systems with Unilateral Contact PDF Author: Albert Peiret Gimenez
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description
"Models based on bodies that interact with each other are also known as multibody systems. Such models are proven to be very useful for representing the motion of many different kinds of systems, from industrial machinery to the human body. In many cases, rigid bodies can be employed if their deformation is negligible compared to their displacement, which significantly reduces the complexity of the model. Moreover, numerical simulations of multibody systems can be very efficient, and be used for real-time interactive applications in engineering and computer animation. The focus of this thesis is on the modelling and simulation of multibody systems, with especial emphasis to unilateral contact and friction between the bodies. The inherent non-smooth nature of contact is approached using the concept of unilateral constraints, which leads the system dynamics to formulate linear complementarity problems. However, these formulations can present inconsistencies when Coulomb friction is used to model contact, which can compromise the solvability of the dynamic equations and the numerical simulation as well. Here, the contact problem is analyzed using a novel representation of the generalized friction cone that is able to capture different phenomena, such as the Painlevé paradox. The framework of this work largely relies on formulations at the impulse-momentum level of multibody system dynamics. Implicit integration schemes make the numerical simulation of such systems stable, as well as robust. Additionally, constraint regularization also helps the model to cope with redundancy of the contact forces. A new regularized friction model based on the bristle approach is presented, which models the flexibility of the system at the contact interface, and is able to capture the static behavior of friction, or sticking. Moreover, other techniques that facilitate the simulation of large scale systems are also proposed herein. Substructuring of multibody systems groups the bodies into subsystems, which allows the system dynamics to be solved in different processing units (CPUs), and reduces the computational time by performing the operations in parallel. This is achieved by means of formulating the effective mass of the system at the coupling interfaces, which can also be used to couple the simulation to other systems of different nature and time-scale, such as hydraulic systems. Interestingly, co-simulation of such multi-physics systems is currently in the spotlight of many engineering applications ranging from virtual prototyping to simulation with hardware in the loop"--

Hybrid Simulation

Hybrid Simulation PDF Author: Victor Saouma
Publisher: CRC Press
ISBN: 1482288613
Category : Computers
Languages : en
Pages : 242

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Book Description
Hybrid Simulation deals with a rapidly evolving technology combining computer simulation (typically finite element) and physical laboratory testing of two complementary substructures. It is a cost effective alternative to shaking table test, and allows for the improved understanding of complex coupled systems. Traditionally, numerical simulation an

IUTAM Symposium on Multiscale Problems in Multibody System Contacts

IUTAM Symposium on Multiscale Problems in Multibody System Contacts PDF Author: Peter Eberhard
Publisher: Springer Science & Business Media
ISBN: 1402059817
Category : Technology & Engineering
Languages : en
Pages : 349

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Book Description
The investigation of multiscale problems in multibody system contacts is an interesting and timely topic which has been the subject of intensive research. This IUTAM Symposium facilitated discussions between researchers active in the field. This proceedings volume summarizes contributions of many authors active in the field and gives insight in very different areas of this fascinating research. It reviews the state-of-the-art and identifies future hot topics.

Proceedings

Proceedings PDF Author:
Publisher:
ISBN:
Category : Automobiles
Languages : en
Pages : 1168

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Book Description


Physics-based Animation

Physics-based Animation PDF Author: Kenny Erleben
Publisher:
ISBN: 9781584503804
Category : Computers
Languages : en
Pages : 817

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Book Description
The booming computer games and animated movie industries continue to drive the graphics community's seemingly insatiable search for increased realism, believability, ad speed. To achieve the quality expected by audiences of today's games and movies, programmers need to understand and implement physics-based animation. To provide this understanding, this book is written to teach students and practitioners and theory behind the mathematical models and techniques required for physics-based animation. It does not teach the basic principles of animation, but rather how to transform theoretical techniques into practical skills. It details how the mathematical models are derived from physical and mathematical principles, and explains how these mathematical models are solved in an efficient, robust, and stable manner with a computer. This impressive and comprehensive volume covers all the issues involved in physics-based animation, including collision detection, geometry, mechanics, differential equations, matrices, quaternions, and more. There is excellent coverage of collision detection algorithms and a detailed overview of a physics system. In addition, numerous examples are provided along with detailed pseudo code for most of the algorithms. This book is ideal for students of animation, researchers in the field, and professionals working in the games and movie industries. Topics Covered: * The Kinematics: Articulated Figures, Forward and Inverse Kinematics, Motion Interpolation * Multibody Animation: Particle Systems, Continuum Models with Finite Differences, the Finite Element Method, Computational Fluid Dynamics * Collision Detection: Broad and Narrow Phase Collision Detection, Contact Determination, Bounding Volume Hierarchies, Feature-and Volume-Based Algorithms

Rigid Body Dynamics Algorithms

Rigid Body Dynamics Algorithms PDF Author: Roy Featherstone
Publisher: Springer
ISBN: 1489975608
Category : Education
Languages : en
Pages : 276

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Book Description
Rigid Body Dynamics Algorithms presents the subject of computational rigid-body dynamics through the medium of spatial 6D vector notation. It explains how to model a rigid-body system and how to analyze it, and it presents the most comprehensive collection of the best rigid-body dynamics algorithms to be found in a single source. The use of spatial vector notation greatly reduces the volume of algebra which allows systems to be described using fewer equations and fewer quantities. It also allows problems to be solved in fewer steps, and solutions to be expressed more succinctly. In addition algorithms are explained simply and clearly, and are expressed in a compact form. The use of spatial vector notation facilitates the implementation of dynamics algorithms on a computer: shorter, simpler code that is easier to write, understand and debug, with no loss of efficiency.

Modeling and Simulation of Contact and Impact Dynamics in Multibody Systems

Modeling and Simulation of Contact and Impact Dynamics in Multibody Systems PDF Author: Abhishek Chatterjee
Publisher:
ISBN:
Category : Contact mechanics
Languages : en
Pages : 198

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Book Description
Contact and impact analyses are an essential part of multibody dynamic simulations.Modeling of contact and impact problems have applications in a wide variety of areas including robotics, earthquake engineering, computer graphics, and manufacturing. Collisions between objects typically take place over surfaces that are represented by a set of points in the operation space, thereby requiring multi-point contact and impact analysis.Analysis of multi-point contact and impact may lead to indeterminate (underdetermined) problems with more number of unknowns (contact forces) than equations.This work pertains to the problem of resolving multi-point contact and impact problems in multibody systems consisting of hard objects, that can be assumed to be rigid.In the first part of this work, a rigidity based modeling and simulation technique is developed for multi-point impacts between hard objects. In this proposed framework impacts are treated as discrete events during which the velocities of the system evolve in the impulse-domain, based on an impulse-momentum theory called Darboux-Keller shock.Constraints derived based on the rigid body assumption are used to resolve indeterminacy associated with multi-point analysis. An energetic terminal constraint is also proposed. based on Stronge's Hypothesis, that guarantees the treatment of impact to be energetically consistent. This approach is used to derive both planar and three-dimensional models of multi-point indeterminate impacts.The rigid impact model based on impulse-momentum theory, developed in the first part of this work, loses some information like force and deformation histories during impacts. This lost information, however can be useful in certain types of application. Hence, to retain this information, the second part of this work proposes a method of augmenting the rigid-impact model with a contact force model from the contact mechanics literature to simultaneously determine the force and deformation histories during an impact event.The contact force model used here is a viscoelastoplastic model of contact that considers the effects of permanent (plastic) deformation in the material. A relationship is developed between the permanent deformations of the material and the energetic terminal constraint proposed in the first part of this work to characterize the force histories during collisions.The accumulation of discrete impact events during the time-domain simulation may lead to chattering or zeno phenomenon, causing the adaptive step-size integration to halt or fail. This work resolves this problem by transitioning to contact when the normal components of the post-impact velocities become very small. During contact, the forces between the participating rigid bodies satisfy the: 1) non-penetrability condition and 2) frictional force constraints based on Coulomb Friction. The non-penetrability condition enforces normal velocity and acceleration constraints on the equations of motion, whereas the Coulomb friction constrains the tangential forces at the contact points. These constraints placed on the equations of motion, lead to a reduction in the number of degrees of freedom (DOF) of the system. This work uses an online constraint embedding technique to enforce contact constraints.