استخراج معادله ساختاري براي رفتار مكانيكي قطعه كار در دماي بالا با استفاده از مقادير اندازه گيري شده در نورد گرم

چكيده انگليسي :

Masoud ZackerZadeh m zackerzadeh@me iut ac ir th April Department of Mechanical Engineering Isfahan University of Technology Isfahan Iran Degree M Sc Language Farsi Supervisor Mostafa Ghayour ghayour@cc iut ac ir Abstract In recent years mobile robots have widely developed for various tasks including building inspection military reconnaissance and planetary exploration and recently it is used in wheelchair design for assistant disabled people The aim of this research is design a wheeled mobile robot for climbing stairs and presenting an algorithm based on friction between wheel and terrain which can move on steps symmetric obstacles and asymmetric obstacles without any complex sensors and the other equipments that they normally are so expensive and they are used in many robots Due to light weight simple controlling algorithm high energy efficiency and low noise wheeled mobile robots have attached much attention Wheeled mobile robot with passive linkage mechanism is capable to adapt with rough terrain and step with appropriates dimension In the chosen robot effective parameters such as links length distance between robot central gravity and ground and wheels mass are selected Optimizing these parameters will result in improvement of stair climbing Due to low speed of robot using quasi static analysis is possible Using this analysis for some special cases results in obtaining reaction forces such as traction and surface reaction force in contact point between robot wheel and the wall of step In order to enhancing robots capability in passing steps robots dimensions are optimized The used optimization method is a multi objective goal attainment problem In this method goal attainment constraints problem and optimization goals are defined Using this method will lead our goal functions to suitable values In the rough terrain it is important for mobile robots to maintain adequate traction as excessive wheel slip cause the robot to lose mobility or even be trapped In the end traction controlling algorithm is implemented based on stick slip phenomenon on the wheel In this algorithm the exerted wheel torque will be between the maximum generated torque due to kinetic and static friction forces on the wheel Then by calculating wheel angular effective parameters on control algorithm are obtained This algorithm is implementing by using ADAMS and MATLAB softwares and the only required information is the wheel angular velocity Using ADAMS angular velocity is calculated then using MATLAB S function Simulink traction controller suitable torque will be applied to wheels by estimation angular acceleration Simulation results show that robot can move on smooth surfaces and surfaces with symmetric and asymmetric obstacles and steps with suitable dimensions Torque angular velocity and angular acceleration graphs related to each path are derived In the path with symmetric obstacles similar results are observed In path with asymmetric obstacles the graphs are not similar due to robot motion By using algorithms robot could up cm step in seconds Result shows that torque exerted on wheel in most period is between maximum static and dynamic friction The steep changes in the simulation results are caused by the instantaneous collision between wheel and the wall of the step Keyword wheelchair mechanism rough terrain ADAMS multi objective goal attainment traction force PDF created with pdfFactory trial version www pdffactory com

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استخراج معادله ساختاري براي رفتار مكانيكي قطعه كار در دماي بالا با استفاده از مقادير اندازه گيري شده در نورد گرم

تنش سيلان , نورد ورق , روش تحليل معكوس , ميانگين مربعات خطا , شبكه هاي عصبي , بهينه سازي