Hybrid Shape Research Articles

An optimum design with sloshing suppression on container transfer control of molten metal using computer fluid dynamics model

This paper presented a control system design method for molten metal's container transfer by using a computer fluid simulator. By means of the computer-aided simulation, sloshing (liquid vibration) phenomena is analyzed and the natural frequency of liquid in a container is identified which plays an important role for controller design. In order to satisfy various control specifications such as sloshing-suppression, transfer time and so on, optimum controller is designed by the Hybrid Shape Approach in consideration of both time and frequency characteristics. By evaluating with computer simulation and experiments, it was found that the proposed method is effective to optimize the process with sloshing suppressed and transfer time shorten. Furthermore, the proposed method is also efficient to reduce the calculation time as compared with conventional ones.

LIQUID LEVEL CONTROL OF AUTOMATIC POURING ROBOT BY TWO-DEGREES-OF-FREEDOM CONTROL

The purpose of this paper is to provide a method to hold the liquid in a sprue cup into the constant level and to suppress sloshing (liquid vibration). This paper uses tilting type automatic pouring robot. A two-degrees-of-freedom control system is used to control the liquid level. This paper presents a series of models representing each part of the pouring process. Through these models, feedforward input can be achieved. Also, to improve the control, two-degrees-of-freedom-control is applied. Liquid vibration inside a ladle after pouring is suppressed by a controller using the Hybrid Shape Approach. As a result, the liquid level in a sprue cap is held to around the setpoint, and sloshing is suppressed. The validity of the proposed control system is demonstrated through experiments.

Sensor-Less Sway Control of Rotary Crane Considering the Collision Avoidance to the Ground.

In recent years, many rotary crane systems used for factories, construction sites, harbors have been studied. However, there are few studies to show the sensorless sway control and collision avoidance to the ground, although it is highly demanded to realize the system in real plants. In this paper, a Load-horizontal control system with sway-suppression is realized by applying Hybrid shape approach and synchronized control. Furthermore, the robustness against the change in rope length and the sensorless sway control are also realized by applying the Hybrid shape approach. The effectiveness of the proposed system is shown through simulatidns and experiments.

Sloshing Analysis and Control System Design of Molten Metal Transfer by Using CFD.

In recent years, many liquid container transfer systems used for the transfer of molten metal in the casting and steel industries have been studied. However, there are few studies to show the control system design method for real molten metal transfer although there are many for water, and it is highly demanded to realize the system in real plants. This paper gives the control system design method for molten metal transfer by using fluid behavior simulator, and realizes the molten metal transfer system. In order to design a feedback controller, sloshing phenomenon is analyzed by using Computational Fluid Dynamics (CFD) Model, and Hybrid Shape Approach is applied. The effectiveness of the proposed design method is shown through real experiment with water and the control simulations based on CFD with molten metal.

MOTION CONTROL OF OMNIDIRECTIONAL WHEELCHAIR CONSIDERING PATIENT COMFORT

An omnidirectional wheelchair is highly maneuverable in narrow or crowded areas such as residences, offices and hospitals. In this paper, a novel motion control system for an omnidirectional wheelchair is proposed. In order to ensure a comfortable ride for the patient, the controller is designed using a hybrid shape approach that considers both time and frequency characteristics. The effectiveness of the proposed system is evaluated by the output signal of a sensor attached to the wheelchair and by a descriptive inspection by several users.

Hybrid element-free Galerkin-finite element method for electromagnetic field computations

A new hybrid computational procedure utilizing the Element-free Galerkin method (EFGM) and the finite element method (FEM) for electromagnetic field computations is proposed. With the proposed method, only a part of the analyzed domain is modeled using the EFGM, while the rest of the analysis domain is discretized using the ordinary FEM. The connection between both subdomains is enabled using an intermediate analysis subdomain where new hybrid shape functions are defined utilizing both EFGM and FEM shape functions as bases. The accuracy of the obtained results by the proposed method is of the same order with those obtained by the ordinary FEM, but with less computation effort.

Fast numerical algorithms for fitting multiresolution hybrid shape models to brain MRI

Fast numerical algorithms for fitting multiresolution hybrid shape models to brain MRI

Fast numerical algorithms for fitting multiresolution hybrid shape models to brain MRI

Fast numerical algorithms for fitting multiresolution hybrid shape models to brain MRI

Fast numerical algorithms for fitting multiresolution hybrid shape models to brain MRI

In this paper, we present new and fast numerical algorithms for shape recovery from brain MRI using multiresolution hybrid shape models. In this modeling framework, shapes are represented by a core rigid shape characterized by a superquadric function and a superimposed displacement function which is characterized by a membrane spline discretized using the finite-element method. Fitting the model to brain MRI data is cast as an energy minimization problem which is solved numerically. We present three new computational methods for model fitting to data. These methods involve novel mathematical derivations that lead to efficient numerical solutions of the model fitting problem. The first method involves using the nonlinear conjugate gradient technique with a diagonal Hessian preconditioner. The second method involves the nonlinear conjugate gradient in the outer loop for solving global parameters of the model and a preconditioned conjugate gradient scheme for solving the local parameters of the model. The third method involves the nonlinear conjugate gradient in the outer loop for solving the global parameters and a combination of the Schur complement formula and the alternating direction-implicit method for solving the local parameters of the model. We demonstrate the efficiency of our model fitting methods via experiments on several MR brain scans.

Global Strength of Hybrid Shape Memory Composite Plates Subjected to Low-Velocity Impact

Deformations and stresses in hybrid shape memory alloy plates subjected to low-velocity impact are considered. Shape memory alloy fibers embedded in resin sleeves and located at the middle plane of the plate can be an effective tool for the reduction of deformations and the control of damage. The desirable effect can be achieved by activating the fibers, i.e., through a constrained reverse transformation. In the examples considered in the paper, transverse deflections were reduced to approximately one-third of the deflections of identical plates without shape memory alloy fibers. Although the benefits to the stresses were less impressive, they were still significant. The accuracy of the closed-form solution presented in the paper is limited only by a number of terms in the series that represent deformations. Numerical analysis reflected a good convergence of the solution.

Multiresolution stochastic hybrid shape models with fractal priors

3D shape modeling has received enormous attention in computer graphics and computer vision over the past decade. Several shape modeling techniques have been proposed in literature, some are local (distributed parameter) while others are global (lumped parameter) in terms of the parameters required to describe the shape. Hybrid models that combine both ends of this parameter spectrum have been in vogue only recently. However, they do not allow a smooth transition between the two extremes of this parameter spectrum. We introduce a new shape-modeling scheme that can transform smoothly from local to global models or vice versa. The modeling scheme utilizes a hybrid primitive called the deformable superquadric constructed in an orthonormal wavelet basis . The multiresolution wavelet basis provides the power to continuously transform from local to global shape deformations and thereby allow for a continuum of shape models—from those with local to those with global shape descriptive power—to be created. The multiresolution wavelet basis allows us to generate fractal surfaces of arbitrary order that can be useful in describing natural detail. We embed these multiresolution shape models in a probabilistic framework and use them for recovery of anatomical structures in the human brain from MRI data. A salient feature of our modeling scheme is that it can naturally allow for the incorporation of prior statistics of a rich variety of shapes. This stems from the fact that, unlike other modeling schemes, in our modeling, we require relatively few parameters to describe a large class of shapes.