Approximate Multi-Objective Optimization of Medical Foot Support: Case of 3D Shape Optimization

2009 ◽  
Author(s):  
Shin-ichiro Miyake ◽  
Suguru Nakao ◽  
Masao Arakawa
Keyword(s):  
Physical Therapists ◽  
Daily Life ◽  
Radial Basis Function Network ◽  
Medical Doctors ◽  
Multi Objective Optimization ◽  
3D Shape ◽  
Multi Objective ◽  
Maximum Reduction ◽  
Design Variables ◽  
Function Network

Splayfoot seems not serious diseases. However, it cause fatigue in the daily life. In that sense, if we can solve these problems it might support daily life much comfortable especially for elder people. To support splayfoot, there are some commercial ones. But they just add small amount of support and not made up for each person. Besides, when the height of support is not suitable for patients, it sometimes makes situation worse. We have tried it and measured by using myoelectric potential measurements, and see differences of three patients. Even if we use the same commercial support its effectiveness differs to each other and sometimes it makes worse. Physical therapists make foot support for each patient but they make them owing to their experience. There are studies on the positions of bone of foot and its portrait of the desired positions has been reported by medical doctors. One of them is called Mizuno standard [1]. In the previous study, we tried to design foot support aiming to make portrait of this standard in vertical space. For that purpose, we used approximate multi-objective optimization using Radial Basis Function network. For validation, we used electromyography again. As a result the foot support by the proposed method showed the maximum reduction in integral of myoelectric. However, in the previous study [2], we only used two design variables, and we have only designed vertical phase. Therefore, we have not completely designed the support. In this study, we use 3D spline expression to make support, and try to design 3D shape of support. In validation, the results of approximate multi-objective optimization show the best reduction in integral of myoelectric, and show the effectiveness of the proposed method.

Approximate Multi-Objective Optimization of Medical Foot Support

2008 ◽  
Author(s):  
Shin-Ichiro Miyake ◽  
Masao Arakawa
Keyword(s):  
Physical Therapists ◽  
Daily Life ◽  
Radial Basis Function Network ◽  
Medical Doctors ◽  
Multi Objective Optimization ◽  
Potential Measurement ◽  
X Ray ◽  
Multi Objective ◽  
Characteristic Points ◽  
Function Network

Splayfoot seems not serious diseases. However, it cause fatigue in the daily life. It makes breakthrough in track athletic and many other fields in sports. In that sense, if we can solve these problems it might support daily life much comfortable especially for elder people. To support splayfoot, there are some commercial ones. But they just add small amount of support and not made up for each person. Besides, when the height of support is not suitable for patients, it sometimes make situation worse. We have tried it and measured by using myoelectric potential measurement, and see differences of three patients. Even if we use the same commercial support its effectiveness differs to each other and sometimes it make worse. Physical therapists make foot support for each patient but they make them owing to their experience. There are studies on the positions of bone of foot and its portrait of the desired positions has been reported by medical doctors. One of them is called Mizuno [1973] standard. In this study, we tried to design foot support aiming to make portrait of this standard. For that purpose, we use approximate multi-objective optimization using Radial Basis Function network. First, we make some support and try to find characteristic points of spline function. These processes have been measured by X-ray and calculated portraits for each X-ray digital image. Then, we have gone through multi-objective optimization and design a foot support for one patient and made it by hard sponge. We measured it by X-ray again to make sure that the portrait has been done in acceptable position. For validation, we use electromyography again. As a result the foot support by the proposed method shows the maximum reduction in integral of myoelastic. This shows the effectiveness of the proposed method.

The Finite Element Analysis and the Multi-Objective Optimization Design of Spindle Systems of CNC Gantry Machine Tools

2016 ◽  
Vol 693 ◽  
pp. 243-250
Author(s):  
Zhi Zhong Guo ◽  
Yun Shun Zhang ◽  
Shi Hao Liu
Keyword(s):  
Machine Tools ◽  
Optimization Design ◽  
Multi Objective Optimization ◽  
Element Analysis ◽  
Multi Objective ◽  
Vibration Resistance ◽  
Design Variables ◽  
Force Coupling ◽  
The Finite Element Analysis ◽  
Spindle Structure

It is discovered that the vibration resistance of spindle systems needs to be improved based on the statics analysis, modal analysis and heating-force coupling analysis of spindle systems of CNC gantry machine tools. The design variables of optimization are set according to sensitivity analysis, multi-objective and dynamic optimization design is realized and its designing scheme is gained for spindle structure. The research results show that vibration resistance can be improved without change of the quality and static property of spindle systems of CNC gantry machine tools.

Multi-objective optimization of a sports car suspension system using simplified quarter-car models

2020 ◽  
Vol 21 (4) ◽  
pp. 412
Author(s):  
Salman Ebrahimi-Nejad ◽  
Majid Kheybari ◽  
Seyed Vahid Nourbakhsh Borujerd
Keyword(s):  
Numerical Solutions ◽  
Suspension System ◽  
Mode Shapes ◽  
Ride Quality ◽  
Multi Objective Optimization ◽  
Multi Objective ◽  
Characteristic Roots ◽  
Design Variables ◽  
Stiffness Matrices ◽  
Quarter Car

In this paper, first, the vibrational governing equations for the suspension system of a selected sports car were derived using Lagrange's Equations. Then, numerical solutions of the equations were obtained to find the characteristic roots of the oscillating system, and the natural frequencies, mode shapes, and mass and stiffness matrices were obtained and verified. Next, the responses to unit step and unit impulse inputs were obtained. The paper compares the effects of various values of the damping coefficient and spring stiffness in order to identify which combination causes better suspension system performance. In this regard, we obtained and compared the time histories and the overshoot values of vehicle unsprung and sprung mass velocities, unsprung mass displacement, and suspension travel for various values of suspension stiffness (KS ) and damping (CS ) in a quarter-car model. Results indicate that the impulse imparted to the wheel is not affected by the values of CS and KS . Increasing KS will increase the maximum values of unsprung and sprung mass velocities and displacements, and increasing the value of CS slightly reduces the maximum values. By increasing both KS and CS we will have a smaller maximum suspension travel value. Although lower values of CS provide better ride quality, very low values are not effective. On the other hand, high values of CS and KS result in a stiffer suspension and the suspension will provide better handling and agility; the suspension should be designed with the best combination of design variables and operation parameters to provide optimum vibration performance. Finally, multi-objective optimization has been performed with the approach of choosing the best value for CS and KS and decreasing the maximum accelerations and displacements of unsprung and sprung masses, according to the TOPSIS method. Based on optimization results, the optimum range of KS is between 130 000–170 000, and the most favorable is 150, and 500 is the optimal mode for CS .

Robustness Against Large Variations in Multi-Objective Optimization Problems

2013 ◽  
Author(s):  
Weijun Wang ◽  
Stéphane Caro ◽  
Fouad Bennis
Keyword(s):  
Optimization Problems ◽  
Optimal Solutions ◽  
Objective Functions ◽  
Multi Objective Optimization ◽  
Design Environment ◽  
Multi Objective ◽  
Uncertainty Sources ◽  
Design Variables ◽  
Robustness Index ◽  
Environment Parameters

In the presence of multiple optimal solutions in multi-modal optimization problems and in multi-objective optimization problems, the designer may be interested in the robustness of those solutions to make a decision. Here, the robustness is related to the sensitivity of the performance functions to uncertainties. The uncertainty sources include the uncertainties in the design variables, in the design environment parameters, in the model of objective functions and in the designer’s preference. There exist many robustness indices in the literature that deal with small variations in the design variables and design environment parameters, but few robustness indices consider large variations. In this paper, a new robustness index is introduced to deal with large variations in the design environment parameters. The proposed index is bounded between zero and one, and measures the probability of a solution to be optimal with respect to the values of the design environment parameters. The larger the robustness index, the more robust the solution with regard to large variations in the design environment parameters. Finally, two illustrative examples are given to highlight the contributions of this paper.

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