A Novel Approach for the Dynamic Analysis and Simulation of Constrained Mechanical Systems

2003 ◽  
Author(s):  
Jo´zsef Ko¨vecses ◽  
Jean-Claude Piedboeuf
Keyword(s):  
Dynamic Analysis ◽  
Potential Application ◽  
Nonholonomic Constraints ◽  
Constrained Systems ◽  
Space Robotics ◽  
Lagrange Principle ◽  
Constrained System ◽  
Constrained Mechanical Systems ◽  
Novel Approach ◽  
Accuracy And Stability

In this paper we will outline a formulation for the dynamics of constrained systems. This formulation relies on the D’Alembert-Lagrange principle and the physically meaningful decomposition of the virtual displacements and the generalized velocities for the system where a redundant, non-minimum set of variables is used. The approach is valid for general constrained system with holonomic and/or nonholonomic constraints. We will also discuss a potential application of this formulation in improving the accuracy and stability of the simulation of constrained systems. This application will be demonstrated by an example drawn from space robotics.

scholarly journals Use of Dynamic Analysis to Investigate the Behaviour of Short Neutral Sections in the Overhead Line Electrification

2021 ◽  
Vol 6 (5) ◽  
pp. 62
Author(s):  
John Morris ◽  
Mark Robinson ◽  
Roberto Palacin
Keyword(s):  
Dynamic Analysis ◽  
Dynamic Simulation ◽  
Model Simulation ◽  
Analysis Tool ◽  
Overhead Line ◽  
Element Analysis ◽  
Novel Approach ◽  
Section Model ◽  
The Uk ◽  
Neutral Section

The ‘short’ neutral section is a feature of alternating current (AC) railway overhead line electrification that is often unreliable and a source of train delays. However hardly any dynamic analysis of its behaviour has been undertaken. This paper briefly describes the work undertaken investigating the possibility of modelling the behaviour using a novel approach. The potential for thus improving the performance of short neutral sections is evaluated, with particular reference to the UK situation. The analysis fundamentally used dynamic simulation of the pantograph and overhead contact line (OCL) interface, implemented using a proprietary finite element analysis tool. The neutral section model was constructed using physical characteristics and laboratory tests data, and was included in a validated pantograph/OCL simulation model. Simulation output of the neutral section behaviour has been validated satisfactorily against real line test data. Using this method the sensitivity of the neutral section performance in relation to particular parameters of its construction was examined. A limited number of parameter adjustments were studied, seeking potential improvements. One such improvement identified involved the additional inclusion of a lever arm at the trailing end of the neutral section. A novel application of pantograph/OCL dynamic simulation to modelling neutral section behaviour has been shown to be useful in assessing the modification of neutral section parameters.

Energy method for modelling delamination buckling in geometrically constrained systems

2003 ◽  
Vol 217 (9) ◽  
pp. 1015-1026 ◽  
Author(s):  
B J Hicks ◽  
G Mullineux ◽  
C Berry ◽  
C J McPherson ◽  
A J Medland
Keyword(s):  
Finite Element ◽  
Full Range ◽  
Constrained Systems ◽  
Third Party ◽  
Constrained System ◽  
Finite Element Approach ◽  
Delamination Buckling ◽  
Element Approach ◽  
Geometrically Constrained ◽  
Energy Formulation

Delamination buckling analysis of laminates is of considerable interest to the mechanical and materials engineering sectors, as well as having wider applications in geology and civil engineering. With advances in computing power, the ability to model ever increasingly complex problems at more detailed levels becomes more of a reality. However, many of the common finite element packages, with the exception of all but the most specialized, do not perform particularly well where complex non-linear problems are dealt with. In many cases, these packages can fail to determine the full range of solutions or accurately predict the properties and geometry of the final state. This is particularly the case where large deformations and buckling of laminates are considered. Because of this, many researchers prefer to use what they perceive to be more reliable techniques, such as the symbolic computation of the underlying differential equations, rather than finite element approaches. The use of finite element packages is further frustrated by the steep learning curve and implicit restrictions imposed by using third-party software. In this paper, a finite element approach and an energy formulation method are considered and used to model the delamination buckling in a geometrically constrained system. These methods are compared with experimental results and their relative merits are discussed. In particular, the accuracy and the ability to represent the geometry of the buckled system are discussed. Both the finite element approach and the energy formulation are described in detail and the numerical results are compared.

On the Use of the Canonical Equations of Motion for the Dynamic Analysis of Constrained Multibody Systems

1992 ◽  
Author(s):  
E. Bayo ◽  
J. M. Jimenez
Keyword(s):  
Dynamic Analysis ◽  
Multibody Systems ◽  
Equations Of Motion ◽  
Mechanical Systems ◽  
Numerical Algorithms ◽  
Constrained Multibody Systems ◽  
Constrained Mechanical Systems ◽  
First Order ◽  
Canonical Variables ◽  
Lagrange’S Multipliers

Abstract We investigate in this paper the different approaches that can be derived from the use of the Hamiltonian or canonical equations of motion for constrained mechanical systems with the intention of responding to the question of whether the use of these equations leads to more efficient and stable numerical algorithms than those coming from acceleration based formalisms. In this process, we propose a new penalty based canonical description of the equations of motion of constrained mechanical systems. This technique leads to a reduced set of first order ordinary differential equations in terms of the canonical variables with no Lagrange’s multipliers involved in the equations. This method shows a clear advantage over the previously proposed acceleration based formulation, in terms of numerical efficiency. In addition, we examine the use of the canonical equations based on independent coordinates, and conclude that in this second case the use of the acceleration based formulation is more advantageous than the canonical counterpart.

scholarly journals Computer-aided autotransplantation of teeth with 3D printed surgical guides and arch bar: a preliminary experience

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5939 ◽  
Author(s):  
Wei He ◽  
Kaiyue Tian ◽  
Xiaoyan Xie ◽  
Enbo Wang ◽  
Nianhui Cui
Keyword(s):  
Survival Rate ◽  
Success Rate ◽  
Three Dimensional ◽  
Three Dimensional Printing ◽  
Surgical Guides ◽  
Arch Bar ◽  
Novel Approach ◽  
Computer Aided ◽  
Wisdom Teeth ◽  
Accuracy And Stability

Background/Aim Autotransplantation of teeth is a method to restore the missing teeth and computer-aided techniques have been applied in this field. The aim of this study was to describe a novel approach for computer-aided autotransplantation of teeth and to preliminarily assess its feasibility, accuracy, and stability. Methods Eight wisdom teeth with complete root formation of eight adult patients were autotransplanted. Individual replicas of donor teeth with local splints, surgical templates, and arch bars were virtually designed and fabricated using three-dimensional printing, these were then applied in the autotransplantation surgeries. Clinical and radiological outcomes were observed, the extra-alveolar time, success rate, and 1-year survival rate were analyzed, and accuracy and stability of this approach were evaluated. Results The extra-alveolar time of donor teeth were less than 3 min. The average follow-up duration was 2.00 ± 1.06 years. All autotransplanted teeth showed normal masticatory function. Ankylosis was found in one patient, and the overall success rate was 87.5%, whereas the 1-year survival rate was 100%. Linear differences between the designed and the immediate autotransplanted positions at crowns and apexes of the donor teeth were 1.43 ± 0.57 and 1.77 ± 0.67 mm, respectively. Linear differences between immediate and the stable positions at crowns and apexes of the donor teeth were 0.66 ± 0.36 and 0.67 ± 0.48 mm, respectively. Conclusion The present study illustrated the feasibility, clinical satisfied accuracy, and stability of a novel approach for computer-aided autotransplantation of teeth. This new approach facilitated the surgical procedure and might be a viable and predictable method for autotransplantation of teeth.

scholarly journals Dynamic Analysis and Circuit Design of a Novel Hyperchaotic System with Fractional-Order Terms

Complexity ◽  
2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Abir Lassoued ◽  
Olfa Boubaker
Keyword(s):  
Dynamic Analysis ◽  
Circuit Design ◽  
Fractional Order ◽  
Potential Application ◽  
Complex Dynamics ◽  
Equilibrium Points ◽  
Hyperchaotic System ◽  
Software Simulation ◽  
Simulation Results ◽  
Hyperchaotic Systems

A novel hyperchaotic system with fractional-order (FO) terms is designed. Its highly complex dynamics are investigated in terms of equilibrium points, Lyapunov spectrum, and attractor forms. It will be shown that the proposed system exhibits larger Lyapunov exponents than related hyperchaotic systems. Finally, to enhance its potential application, a related circuit is designed by using the MultiSIM Software. Simulation results verify the effectiveness of the suggested circuit.

An effective approach for dynamic analysis of rovers

Robotica ◽  
2005 ◽  
Vol 23 (6) ◽  
pp. 771-780 ◽  
Author(s):  
A. Meghdari ◽  
R. Karimi ◽  
H. N. Pishkenari ◽  
A. L. Gaskarimahalle ◽  
S. H. Mahboobi
Keyword(s):  
High Speed ◽  
Inverse Dynamics ◽  
Nonholonomic Constraints ◽  
Performance Comparison ◽  
Control Algorithms ◽  
Novel Approach ◽  
Dynamic Formulation ◽  
Dynamical Optimization ◽  
Frame Work ◽  
Multi Body

In this paper a novel approach to dynamic formulation of rovers has been presented. The complexity of these multi-body systems especially on rough terrain, challenged us to use the Kane's method which has been preferred to others in these cases. As an example, symbolic equations of a six-wheeled rover, named CEDRA Rescue Robot which uses a shrimp like mechanism, have been derived and a simulation of forward and inverse dynamics has been presented. Due to the clear form of equations, each term defines a physical meaning which represents the effect of each parameter, resulting in a frame-work for performance comparison of rovers. Although the method has been described for a 2-D non-slipping case, it is also very useful for dimensional and dynamical optimization, high speed motion analysis, and checking various control algorithms. Furthermore, it can be extended to 3-D cases and other complicated mechanisms and rovers while conserving its inherent benefits and adding to the ease of handling nonholonomic constraints.

Explicit Poincaré equations of motion for general constrained systems. Part I. Analytical results

2007 ◽  
Vol 463 (2082) ◽  
pp. 1421-1434 ◽  
Author(s):  
Firdaus E Udwadia ◽  
Phailaung Phohomsiri
Keyword(s):  
Equations Of Motion ◽  
Mechanical Systems ◽  
Nonholonomic Constraints ◽  
Constrained Systems ◽  
Analytical Results ◽  
Multi Body ◽  
D'alembert's Principle

This paper gives the general constrained Poincaré equations of motion for mechanical systems subjected to holonomic and/or nonholonomic constraints that may or may not satisfy d'Alembert's principle at each instant of time. It also extends Gauss's principle of least constraint to include quasi-accelerations when the constraints are ideal, thereby expanding the compass of this principle considerably. The new equations provide deeper insights into the dynamics of multi-body systems and point to new ways for controlling them.

Simulation of Constrained Mechanical Systems—Part II: Explicit Numerical Integration

2012 ◽  
Vol 79 (4) ◽  
Author(s):  
David J. Braun ◽  
Michael Goldfarb
Keyword(s):  
Mechanical Systems ◽  
Nonholonomic Constraints ◽  
Direct Consequence ◽  
Differential Algebraic Equations ◽  
Algebraic Equations ◽  
Constrained Motion ◽  
Constrained Mechanical Systems ◽  
Holonomic And Nonholonomic Constraints ◽  
Long Time ◽  
Constraint Correction

This paper presents an explicit to integrate differential algebraic equations (DAEs) method for simulations of constrained mechanical systems modeled with holonomic and nonholonomic constraints. The proposed DAE integrator is based on the equation of constrained motion developed in Part I of this work, which is discretized here using explicit ordinary differential equation schemes and applied to solve two nontrivial examples. The obtained results show that this integrator allows one to precisely solve constrained mechanical systems through long time periods. Unlike many other implicit DAE solvers which utilize iterative constraint correction, the presented DAE integrator is explicit, and it does not use any iteration. As a direct consequence, the present formulation is simple to implement, and is also well suited for real-time applications.

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