scholarly journals Development of Dynamics for Design Procedure of Novel Grating Tiling Device with Experimental Validation

2021 ◽  
Vol 11 (24) ◽  
pp. 11716
Author(s):  
Qingshun Bai ◽  
Mohamed Shehata ◽  
Ayman Nada ◽  
Zhongxi Shao
Keyword(s):  
Dimensional Space ◽  
Three Dimensional ◽  
Real Life ◽  
Design Procedure ◽  
Industrial Applications ◽  
Differential Algebraic Equations ◽  
System Stability ◽  
Design Parameters ◽  
Measuring Instruments ◽  
Algebraic Equations

The article proposes a dynamic for design (DFD) procedure for a novel aperture grating tiling device using the multibody system (MBS) approach. The grating device is considered as a rigid-flexible MBS that is built primarily based totally at the load assumptions because of grating movement. This movement is utilized in many industrial applications, such as the compression of laser pulse, precision measuring instruments, and optical communication. A new design procedure of tiling grating device frame is introduced in order to optimize its design parameters and enhance the system stability. The dynamic loads are estimated based on the Lagrange multipliers that are obtained from the solution of the MBS model. This model is fully non-linear and moves in the three-dimensional space, and the relative movement of its bodies is restricted by the description of the constraints function in the motion manifold. The mechanism of the grating device is structurally analyzed in keeping with the dynamic conduct and therefore the generated forces. The symbolic manipulation as well as the computational work of solving the obtained differential-algebraic equations (DAEs) is carried out using MATLAB Symbolic Toolbox. Once the preliminary design has been attained, the stress behavior of the grating device is examined using the MATLAB FEATool Multiphysics toolkit, regarding system stability and design aspects. Moreover, the design was constructed in real life, and the movement has been verified experimentally, which confirms the effectiveness of the proposed procedure. In conclusion, the DFD procedure with trade-off optimization is utilized successfully to design the grating unit for maximum ranges of grating movements.

Trajectory Tracking of Underactuated Multibody Systems

2011 ◽  
Author(s):  
Stefan Reichl ◽  
Wolfgang Steiner
Keyword(s):  
Trajectory Tracking ◽  
Multibody Systems ◽  
Degrees Of Freedom ◽  
Inverse Dynamics ◽  
Feedforward Control ◽  
Equations Of Motion ◽  
Three Dimensional ◽  
Differential Algebraic Equations ◽  
State Variables ◽  
Algebraic Equations

This work presents three different approaches in inverse dynamics for the solution of trajectory tracking problems in underactuated multibody systems. Such systems are characterized by less control inputs than degrees of freedom. The first approach uses an extension of the equations of motion by geometric and control constraints. This results in index-five differential-algebraic equations. A projection method is used to reduce the systems index and the resulting equations are solved numerically. The second method is a flatness-based feedforward control design. Input and state variables can be parameterized by the flat outputs and their time derivatives up to a certain order. The third approach uses an optimal control algorithm which is based on the minimization of a cost functional including system outputs and desired trajectory. It has to be distinguished between direct and indirect methods. These specific methods are applied to an underactuated planar crane and a three-dimensional rotary crane.

Extension of the Stator Vane Upstream Across the 180° Bend for a Multistage Radial Compressor Stage

2009 ◽  
Author(s):  
Christian Aalburg ◽  
Alexander Simpson ◽  
Jorge Carretero ◽  
Tue Nguyen ◽  
Vittorio Michelassi
Keyword(s):  
Three Dimensional ◽  
Design Procedure ◽  
Design Parameters ◽  
Optimized Design ◽  
Angle Distribution ◽  
Conventional Design ◽  
Stator Vane ◽  
Limited Applicability ◽  
Return Channel ◽  
Vane Angle

The design, analysis and optimization of a new stator concept for multistage centrifugal compressors using numerical methods is presented. The first objective was to further improve the performance of a well-optimized stage with a short vaneless diffuser, see Aalburg et al [1]. The second objective was to achieve a significant increase in the flow turning in the stator part. In order to achieve these goals an extension of the return channel vane upstream, over the U-turn bend, was considered. This design poses challenges that are quite different from those encountered for a conventional design. For example, a conventional vane angle distribution leads to lean angles across the bend that are not feasible from a manufacturing and aerodynamic perspective. In addition, conventional design tools for geometry generation were found to have limited applicability for this concept. To address these issues a geometry generator was developed that facilitated the design of three-dimensional across-the-bend type vanes with unconventional vane angle distributions. The geometry generator was based on an analytical design procedure similar to that outlined by Veress and Braembussche [2]. This procedure allows a desired loading distribution to be specified. In this paper the vane concept will be introduced, the development of the geometry generator will be outlined and the effect of varying design parameters will be considered. An optimized design will then be presented that outperformed the reference conventional design in terms of efficiency by up to one point across the operating range. This improvement was achieved despite a significantly higher vane loading.

Application of Scaling to Multibody Dynamics Simulations

2015 ◽  
Author(s):  
William Prescott
Keyword(s):  
Equations Of Motion ◽  
Industrial Applications ◽  
Differential Algebraic Equations ◽  
Algebraic Equations ◽  
Step Size ◽  
Virtual Lab ◽  
Long Run ◽  
Multibody Dynamic ◽  
Dynamics Simulations ◽  
Stability Issues

This paper will examine the importance of applying scaling to the equations of motion for multibody dynamic systems when applied to industrial applications. If a Cartesian formulation is used to formulate the equations of motion of a multibody dynamic system the resulting equations are a set of differential algebraic equations (DAEs). The algebraic components of the DAEs arise from appending the joint equations used to model revolute, cylindrical, translational and other joints to the Newton-Euler dynamic equations of motion. Stability issues can arise in an ill-conditioned Jacobian matrix of the integration method this will result in poor convergence of the implicit integrator’s Newton method. The repeated failures of the Newton’s method will require a small step size and therefore simulations that require long run times to complete. Recent advances in rescaling the equations of motion have been proposed to address this problem. This paper will see if these methods or a variant addresses not only stability concerns, but also efficiency. The scaling techniques are applied to the Gear-Gupta-Leimkuhler (GGL) formulation for multibody problems by embedding them into the commercial multibody code (MBS) Virtual. Lab Motion and then use them to solve an industrial sized automotive example to see if performance is improved.

Review of Knee Models: 1996 Update

1996 ◽  
Vol 49 (10S) ◽  
pp. S187-S193 ◽  
Author(s):  
Mohamed Samir Hefzy ◽  
T. Derek V. Cooke
Keyword(s):  
Knee Joint ◽  
Three Dimensional ◽  
Differential Algebraic Equations ◽  
Algebraic Equations ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Full Extension ◽  
Body Contact ◽  
Patellar Cartilage ◽  
Three Body

This paper is an update on our previous review of knee models (Hefzy and Grood [30]). We find that progress was made in the area of dynamic modeling. Since 1988, a technique was developed to solve the system of differential algebraic equations describing the three-dimensional dynamic behavior of the knee joint. This technique allows to solve complex problems. However, not a single dynamic comprehensive anatomically based mathematical three-dimensional model of the knee joint that includes both tibio-femoral and patello-femoral joints has yet been developed. In the area of meniscal modeling, we find that only one three-dimensional model of the knee joint that includes the menisci is available in the literature. This quasi-static model includes menisci, tibial, femoral and patellar cartilage layers, and ligamentous structures. This model is limited since it solves only for one position of the knee joint: full extension. From this updated survey, we conclude that the development of a comprehensive three-dimensional anatomically based mathematical model of the knee joint (that solves the three-body contact problem at the tibio-femoral joint between the menisci, tibia and femur, and includes the patello-femoral joint) continues to present major challenge.

Antigravity Slopes

2017 ◽  
Author(s):  
Kokichi Sugihara
Keyword(s):  
Human Brain ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Real Life ◽  
Two Dimensional ◽  
Single View ◽  
Dimensional Image ◽  
Two Dimensional Image ◽  
New Type ◽  
Law Of Gravity

A new type of illusion, called the antigravity slope illusion, is presented in this chapter. In this illusion a slope orientation is perceived opposite to the true orientation and hence a ball put on it appears to be rolling uphill, defying the law of gravity. This illusion is based on the ambiguity in the distance from a viewpoint to the surface of a three-dimensional solid represented in a single-view image. This illusion also arises in human real life, for example, when a car driver misunderstands the orientation of a road along which he or she is driving. Two assumptions are explored: (a) the human brain prefers to interpret vertical columns in a two-dimensional image as being vertical in three-dimensional space to being slanted and (b) the human brain prefers the most symmetric shape as the interpretation of a two-dimensional image.

scholarly journals Design and construction of a continuous impregnation apparatus of woven fibres, using non-meshing double-sinusoidal toothed rollers

2020 ◽  
Vol 317 ◽  
pp. 01006
Author(s):  
G. Vasileiou ◽  
C. Vakouftsis ◽  
N. Rogkas ◽  
S. Tsolakis ◽  
P. Zalimidis ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Theoretical Calculations ◽  
Dimensional Space ◽  
Continuous Production ◽  
Three Dimensional ◽  
Industrial Applications ◽  
Three Dimensions ◽  
Main Challenge ◽  
Complete Failure ◽  
As Stress

Resin-impregnated fibres are extensively used in a variety of industrial applications as is demonstrated in the literature. Resin-fibre impregnation techniques are used in order to create homogeneous macro – materials and to take full advantage of the mechanical properties of the fibrous reinforcement (i.e. carbon, glass, organic or ceramic fibres). However, achieving highly impregnated fibres is proven quite challenging especially in continuous production techniques that are required for large production rates. The main challenge lies in achieving complete impregnation of the tightly arranged fibres mainly referring to the formed yarns containing multiple fibres, sometimes even twisted. This results in partially impregnated materials containing cavities that tend to exhibit inferior mechanical properties compared to the theoretical calculations, which assume fully impregnated materials. These cavities often lead to crack generation, acting as stress concentration sites, resulting in complete failure of the material at macro-level. In this paper a novel technique for continuous production of fully impregnated woven fibres is presented using non – meshing, co – rotating rollers. A laboratory-scale apparatus is designed and described thoroughly in the context of this work. The method resembles pultrusion in the sense that a reinforcement plain fibre mesh (glass) is co–processed with the liquid resin through a pair of co–rotating toothed rollers to produce a continuously reinforced 3D tape. The surface of the rollers is produced from a double-sinusoidal toothed surface (rack) using the Theory of Gearing in three-dimensions, which imposes significant differential sliding of the fibres without differential tension and facilitates fibre wetting. The geometry of the rollers is calculated not to damage the unprocessed fibres, while facilitating local widespreading of the stranded fibres in the three – dimensional space leading to the resin being able to fully penetrate the reinforcing fibre material.

Queueing in space

1994 ◽  
Vol 26 (04) ◽  
pp. 1095-1116 ◽  
Author(s):  
Eitan Altman ◽  
Hanoch Levy
Keyword(s):  
Convex Space ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Finite Size ◽  
System Stability ◽  
Single Server ◽  
Greedy Method ◽  
Service Policies ◽  
The Stability ◽  
Greedy Policy

We consider a problem in which a single server must serve a stream of customers whose arrivals are distributed over a finite-size convex space. Under the assumption that the server has full information on the customer location, obvious service policies are the FCFS and the greedy (serve-the-closest-customer) approaches. These algorithms are, however, either inefficient (FCFS) or ‘unfair' (greedy). We propose and study two alternative algorithms, the gated-greedy policy and the gated-scan policy, which are more ‘fair' than the pure greedy method. We show that the stability conditions of the gated-greedy are p < 1 (where p is the expected rate at which work arrives at the system), implying that the method is at least as efficient (in terms of system stability) as any other discipline, in particular the greedy one. For the gated-scan policy we show that for any p < 1 one can design a stable gated-scan policy; however, for any fixed gated-scan policy there exists p < 1 for which the policy is unstable. We evaluate the performance of the gated-scan policy, and present bounds for the performance of the gated-greedy policy. These results are derived for systems in which the arrivals occur on a two-dimensional space (a square) but they are not limited to this configuration; rather they hold for more complex N-dimensional spaces, in particular for serving customers in (three-dimensional) convex space and serving customers on a line.

Design and Modeling of a Spherical Actuator with Three Dimensional Orientation Measurement System

2011 ◽  
Vol 317-319 ◽  
pp. 1088-1097 ◽  
Author(s):  
Wei Hai Chen ◽  
Liang Zhang ◽  
Fang Hong Guo ◽  
Jing Meng Liu
Keyword(s):  
Permanent Magnet ◽  
Measurement System ◽  
Three Dimensional ◽  
Design Procedure ◽  
Design Parameters ◽  
Orientation Measurement ◽  
Air Core ◽  
Experimental Works ◽  
High Torque ◽  
Spherical Actuator

This paper presents the design and modeling of a permanent magnet spherical actuator which consists of a rotor with eight cylindrical permanent magnet (PM) poles and a stator with twenty-four air-core coils. Torque and dynamic model of this PM spherical actuator are formulated analytically. An optimal design procedure is proposed to achieve a high torque output, and significant design parameters of the actuator are discussed. As there is no effective method for three dimensional orientation measurement of the spherical actuator currently, a novel orientation measurement system is proposed. Finally, experimental works are carried out, and the experiment results demonstrate the effectiveness of the proposed orientation measurement system.

Three-Dimensional Modeling of Opposed Biconical Cone Screw High-Pressure Seawater Hydraulic Pump

2013 ◽  
Vol 310 ◽  
pp. 287-293 ◽  
Author(s):  
Xin Hua Wang ◽  
Zhi Ben Gong ◽  
Li Wei Wang ◽  
Shun Wen Sun ◽  
Gang Zheng
Keyword(s):  
High Pressure ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Design Parameters ◽  
Hydraulic Pump ◽  
Three Dimensional Modeling ◽  
Dimensional Modeling ◽  
New Type ◽  
Design And Manufacture ◽  
Matlab Programming

The rotor and stator were major components of the opposed biconinal cone screw high pressure seawater hydraulic pump, which precision of design and manufacture was particularly high, and the combining status between the stator and rotor has a significant impact on the performance of the new type pump, so the related research on above problems are carried out. In order to satisfy the demands of design efficiency and manufacture decision, a fast and simple way was presented to model 3D cone screw and bushing. Three-dimensional space Cartesian coordinates of cone screw and bushing profile with MATLAB programming were obtained according to the cone screw and bushing surface equation and the design parameters,3D curves of cone screw and bushing with MATLAB were rendered, and the feature point space coordinates were imported to Pro/Engineer so as to build cone screw and bushing solid model. Finally, making virtual assembly and checking interference on the screw and the bushing were necessary. The proposed method can make the complex 3D modeling more accurate, feasible and efficient.

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