scholarly journals Abstract Rotations for Uniform Adaptive Control and Soft Modeling of Mechanical Devices

2021 ◽  
Vol 11 (17) ◽  
pp. 7939
Author(s):  
János F. Bitó ◽  
Imre J. Rudas ◽  
József K. Tar ◽  
Árpád Varga
Keyword(s):  
Dynamic Models ◽  
Direct Method ◽  
Analytical Models ◽  
Adaptive Techniques ◽  
Modeling Methodology ◽  
Error Metrics ◽  
Adaptation Rules ◽  
Mechanical Devices ◽  
Two Degree Of Freedom ◽  
Soft Modeling

The model-based controllers generally suffer from the lack of precise dynamic models. Making reliable analytical models can be evaded by soft modeling techniques, while the consequences of modeling imprecisions are tackled by either robust or adaptive techniques. In robotics, the prevailing adaptive techniques are based on Lyapunov’s “direct method” that normally uses special error metrics and adaptation rules containing fragments of the Lyapunov function. The soft models and controllers need massive parallelism and suffer from the curse of dimensionality. A different adaptive approach based on Banach’s fixed point theorem and using special abstract rotations was recently suggested. Similar rotations were suggested to develop particular neural network-like soft models, too. Presently, via integrating these approaches, a uniform adaptive controlling and modeling methodology is suggested with especial emphasis on the effects of the measurement noises. Its applicability is investigated via simulations for a two degree of freedom mechanical system in which one of the generalized coordinates is under control, while the other one belongs to a coupled parasite dynamical system. The results are promising for allowing the development of relatively coarse soft models and a simple adaptive rule that can be implemented in embedded systems.

New Higher-Order Models for Sandwich Plates with a Flexible Core and their Accuracy Assessment

2019 ◽  
Vol 19 (03) ◽  
pp. 1950024 ◽  
Author(s):  
Ali Tian ◽  
Renchuan Ye ◽  
Peng Ren ◽  
Pengming Jiang ◽  
Zengtao Chen ◽  
...  
Keyword(s):  
Dynamic Models ◽  
Accuracy Assessment ◽  
Order Theory ◽  
Higher Order ◽  
Analytical Models ◽  
Core Material ◽  
Sandwich Plates ◽  
Higher Order Theory ◽  
Flexible Core

Two higher-order analytical models based on a new higher-order theory for sandwich plates with flexible cores are developed considering the effect of the core material density and skin-to-core-stiffness-ratio (SCSR). The main difference between the two models is the role of the flexible core in the dynamic response of sandwich plates with cores of different stiffnesses. Firstly, the governing equations of a simply supported sandwich plate with a flexible core are derived based on the two models, and the analytical solutions are determined by using Navier’s approach. Then, the free vibration, static, dynamic bending and stress field characteristics of the sandwich plates with different SCSRs are investigated. The results obtained by the proposed method are compared with other published results. In particular, an accuracy assessment of the present dynamic models is conducted for different SCSRs. Finally, conclusions on the applicability of the proposed method and other theories on sandwich plates with different SCSRs are drawn.

scholarly journals SPINET: A Parallel Computing Approach to Spine Simulations

1996 ◽  
Vol 5 (1) ◽  
pp. 15-24 ◽  
Author(s):  
Peter G. Kropf ◽  
Edgar F. A. Lederer ◽  
Thomas Steffen ◽  
Karl Guggisberg ◽  
Jean-Guy Schneider ◽  
...  
Keyword(s):  
Finite Element ◽  
Parallel Computing ◽  
Functional Programming ◽  
High Performance ◽  
Dynamic Models ◽  
Spinal Injury ◽  
Direct Method ◽  
Finite Element Program ◽  
Biomechanical Models ◽  
Interdisciplinary Approaches

Research in scientitic programming enables us to realize more and more complex applications, and on the other hand, application-driven demands on computing methods and power are continuously growing. Therefore, interdisciplinary approaches become more widely used. The interdisciplinary SPINET project presented in this article applies modern scientific computing tools to biomechanical simulations: parallel computing and symbolic and modern functional programming. The target application is the human spine. Simulations of the spine help us to investigate and better understand the mechanisms of back pain and spinal injury. Two approaches have been used: the first uses the finite element method for high-performance simulations of static biomechanical models, and the second generates a simulation developmenttool for experimenting with different dynamic models. A finite element program for static analysis has been parallelized for the MUSIC machine. To solve the sparse system of linear equations, a conjugate gradient solver (iterative method) and a frontal solver (direct method) have been implemented. The preprocessor required for the frontal solver is written in the modern functional programming language SML, the solver itself in C, thus exploiting the characteristic advantages of both functional and imperative programming. The speedup analysis of both solvers show very satisfactory results for this irregular problem. A mixed symbolic-numeric environment for rigid body system simulations is presented. It automatically generates C code from a problem specification expressed by the Lagrange formalism using Maple.

Discrete modular serpentine robotic tail: design, analysis and experimentation

Robotica ◽  
2018 ◽  
Vol 36 (7) ◽  
pp. 994-1018 ◽  
Author(s):  
Wael Saab ◽  
William S. Rone ◽  
Pinhas Ben-Tzvi
Keyword(s):  
Dynamic Models ◽  
Design Analysis ◽  
Degree Of Freedom ◽  
Legged Robots ◽  
Design Parameters ◽  
Inertial Loading ◽  
Forward Kinematic ◽  
The Impact ◽  
Accuracy And Repeatability ◽  
Two Degree Of Freedom

SUMMARYThis paper presents the design, analysis and experimentation of a Discrete Modular Serpentine Tail (DMST). The mechanism is envisioned for use as a robotic tail integrated onto mobile legged robots to provide a means, separate from the legs, to aid stabilization and maneuvering for both static and dynamic applications. The DMST is a modular two-degree-of-freedom (DOF) articulated, under-actuated mechanism, inspired by continuum and serpentine robotic structures. It is constructed from rigid links with cylindrical contoured grooves that act as pulleys to route and maintain equal displacements in antagonistic cable pairs that are connected to a multi-diameter pulley. Spatial tail curvatures are produced by adding a roll-DOF to rotate the bending plane of the planar tail curvatures. Kinematic and dynamic models of the cable-driven mechanism are developed to analyze the impact of trajectory and design parameters on the loading profiles transferred through the tail base. Experiments using a prototype are performed to validate the forward kinematic and dynamic models, determine the mechanism's accuracy and repeatability, and measure the mechanism's ability to generate inertial loading.

scholarly journals Nonlinear reaction-diffusion models of self-organization and deterministic chaos: Theory and possible applications to description of electrical cardiac activity and cardiovascular circulation

2006 ◽  
Vol 2006 ◽  
pp. 1-16 ◽  
Author(s):  
V. Kardashov ◽  
Sh. Einav ◽  
Y. Okrent ◽  
T. Kardashov
Keyword(s):  
Signal Processing ◽  
Pulse Propagation ◽  
Dynamic Models ◽  
Deterministic Chaos ◽  
Cardiac Activity ◽  
Reaction Diffusion ◽  
Analytical Models ◽  
Self Organization ◽  
Pressure Pulses ◽  
Chaos Degree

The paper shows that analytical dynamic models coupled with the available signal processing methods could be used for describing the self-organization and chaos degree in the heartbeats propagation and pressure pulses in ventricular at ejection phase. We proposed a unit analytical approach that could be associated with real ECG and pressure pulses signal processing. Our findings confirm that the real-time computer monitoring of the main cardiovascular parameters obtained by the use of analytical models and verified by signal processing of real clinical data may be considered as available method for measuring and controlling self-organization and chaos degree in pulse propagation.

Multi Robot System Dynamics and Path Tracking

2020 ◽  
Vol 16 (2) ◽  
pp. 1-7
Author(s):  
Yousif Khairullah ◽  
Ali Marhoon ◽  
Mofeed Rashid ◽  
Abdulmuttalib Rashid
Keyword(s):  
High Performance ◽  
Dynamic Models ◽  
Direct Method ◽  
Kinematic Model ◽  
Estimation Method ◽  
Physical Structure ◽  
Least Square ◽  
Robot System ◽  
Attraction Behavior ◽  
Multi Robot

The Leader detecting and following are one of the main challenges in designing a leader-follower multi-robot system, in addition to the challenge of achieving the formation between the robots, while tracking the leader. The biological system is one of the main sources of inspiration for understanding and designing such multi-robot systems, especially, the aggregations that follow an external stimulus such as light. In this paper, a multi-robot system in which the robots are following a spotlight is designed based on the behavior of the Artemia aggregations. Three models are designed: kinematic and two dynamic models. The kinematic model reveals the light attraction behavior of the Artemia aggregations. The dynamic model will be derived based on the newton equation of forces and its parameters are evaluated by two methods: first, a direct method based on the physical structure of the robot and, second, the Least Square Parameter Estimation method. Several experiments are implemented in order to check the success of the three proposed systems and compare their performance. The experiments are divided into three scenarios of simulation according to three paths: the straight line, circle, zigzag path. The V-Rep software has been used for the simulation and the results appeared the success of the proposed system and the high performance of tracking the spotlight and achieving the flock formation, especially the dynamic models.

Modeling and Experimental Evaluation of Asymmetric Pantograph Dynamics

1988 ◽  
Vol 110 (2) ◽  
pp. 168-174 ◽  
Author(s):  
S. D. Eppinger ◽  
D. N. O’Connor ◽  
W. P. Seering ◽  
D. N. Wormley
Keyword(s):  
High Performance ◽  
Degrees Of Freedom ◽  
Dynamic Models ◽  
Dynamic Testing ◽  
Dynamic Performance ◽  
Performance Model ◽  
Degree Of Freedom ◽  
Additional Degree ◽  
Three Degree Of Freedom ◽  
Two Degree Of Freedom

High-performance pantograph design requires control of pantograph dynamic performance. Many pantograph dynamic models developed to aid in the design process have employed two degrees of freedom, one for the head mass and one for the frame. In this paper, the applicability of these models to symmetric and asymmetric pantograph designs is reviewed. Two degree-of-freedom models have been shown to be appropriate to represent a number of symmetric pantograph designs. To represent the asymmetric designs considered in this paper, an additional degree of freedom representing frame dynamics has been introduced to yield a three degree-of-freedom nonlinear dynamic performance model. The model has been evaluated with experimental data obtained from laboratory dynamic testing of an asymmetric pantograph.

An Efficient Scaling Methodology for Dynamic Models Using Dimensional and Activity Analyses

2006 ◽  
Author(s):  
Burit Kittirungsi ◽  
Hosam K. Fathy ◽  
Jeffrey L. Stein
Keyword(s):  
Fuel Cell ◽  
System Design ◽  
Scaling Laws ◽  
Dynamic Models ◽  
Cell System ◽  
Air Supply ◽  
Scaling Methods ◽  
Mass Spring ◽  
Two Degree Of Freedom ◽  
System Power

Previous work in the literature developed similitude-based design scaling techniques that make it possible to take a proven system design and scale it to meet new desired dynamic characteristics. However, such similitude-based scaling is often too restrictive because it may not be feasible to satisfy all of the resulting scaling laws exactly. This paper uses a novel combination of activity-based model reduction and dimensional analysis to scale only the important components of a given dynamic system, thereby providing more freedom than pure similitude-based scaling. The viability of this proposed method is highlighted by two examples. The first example demonstrates the proposed efficient scaling methodology on a simple two-degree-of-freedom mass-spring-damper system. The second example uses the developed methodology to scale a fuel cell stack's air supply system design for a new set of fuel cell system power requirements. The examples highlight the flexibility that activity analysis adds to similitude-based scaling methods.

Networked Assembly of Mechatronic Linear Physical System Models

2009 ◽  
Vol 131 (2) ◽  
Author(s):  
Clark J. Radcliffe ◽  
Eliot Motato ◽  
Drew Reichenbach
Keyword(s):  
Physical System ◽  
Dynamic Models ◽  
External Input ◽  
Global Network ◽  
Analytical Models ◽  
Thermal Dynamics ◽  
Efficient System ◽  
Standard Format ◽  
System Models ◽  
Assembly Method

Engineering design is evolving into a global activity. Globally distributed design requires efficient global distribution of models of dynamic physical systems through computer networks. These models must describe the external input-output behavior of the electrical, mechanical, fluid, and thermal dynamics of engineering systems. An efficient system model assembly method is then required to assemble these component system models into a model of a yet higher-level dynamic system. Done recursively, these higher-level system models become possible components for yet higher-level analytical models composed of external model equations in the same standardized format as that of the lowest level components. Real-time, automated exchange, and assembly of engineering dynamic models over a global network requires four characteristics. The models exchanged must have a unique standard format so that they can be exchanged and assembled by an automated process. The exchange of model information must be executed in a single-query transmission to minimize network load. The models must describe only external behavior to protect internal model details. Finally, the assembly process must be recursive so that the transfer and assembly processes do not change with the level of the model exchanged or assembled. This paper will introduce the modular modeling method (MMM), a modeling strategy that satisfies these requirements. The MMM distributes and assembles linear dynamic physical system models with a dynamic matrix representation. Using the MMM method, dynamic models of complex assemblies can be built and distributed while hiding the topology and characteristics of their dynamic subassemblies.

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