Sharif Digital Repository

In this thesis, kinematic, dynamic modeling and simulation, and control of SQ15-06N industrial robot have been presented. This robot is mostly used in the painting industry. Studying the robot requires familiarity with the robot programming and the hardware used in the robot. In this research, robot characteristics such as repeatability, load carrying capacity and accessibility have been investigated. The principles of industrial robot programming and robot programming language have been studied. The use of simulation software is common due to cost savings, reduced time, no need for robots and controllers, and the ability to test programs in a virtual environment. For this purpose, the... 

In recent years, industrial robots have been greatly used as orienting devices in industry, especially in the automotive, shipbuilding and aerospace manufacturing industries. Industrial robots are gradually finding their niche in manufacturing, replacing less universal and more expensive CNC-machines. Application area of robots is constantly growing; they begin to be used for the assembly, pick-and-place operations, machining operations and etc. The use of robots for machining operations is growing because of their flexibility to perform a broad spectrum of tasks at a lower cost when compared with machine tools. Recently, parallel robots have attracted more and more researchers’ attention in... 

Recent studies show that spherical shape robots have been widely developed by many robotic researchers. A spherical shape can be also benefited in keeping mechanical components and electronic circuits inside a compact volume. The shell can also perform rolling motions for going fast and smooth on flat area. The reconfigurable spherical robot can be configured into a form of two interconnected hemispheres with three legs equipped with three Omni-directional wheels. The conceptual design of the robot will be initially packed and deployed in a spherical configuration. The spherical construction offers ease in transportation and deployment; for example, a number of these robots can be packed and... 

Cooperative systems have been widely studied in literature. The Dual-Arm Cam-Locked (DACL) robot manipulators are reconfigurable arms formed by two parallel cooperative manipulators which operate redundantly but they may lock into each other in specific joints to increase structural stiffness in the cost of losing some degrees of freedom. Obtaining the optimal configuration demands lots of computational time and is not practical in real-time applications. In the present work, considering the kinematics of the manipulator, the optimal control problem of redundancy is formulated in the framework of tasks with the order of priority. The optimal control formulation is derived by using the... 

In this project the goal is to study where, when and how the cracks in the steel connection plate between beam and column initiate and how far would the crack grow before failure and how to detect crack initiation by utilizing piezoelectric sensors. In this analysis piezoelectric is placed in line of crack propagation for sensing strain and changing it to voltage. A thin plate with edge notch which is an ideal model of typical beam to column connection is assumed. The plate is subjected to a uniaxial uniform load. With the aid of ANSYS software, the plate is analyzed in both elastic and plastic stages. The strain-stress curve with kinematic hardening part is considered and modeled with... 

The constitutive modeling of material is clearly a keystone of successful quantitative solution possibilities. No finite element code will provide results of better quality than that of the constitutive equation implemented in it. In this study, a nonassociated three-invariant cap plasticity model is presented for material under compressive stress. Generalized single-cap plasticity is developed which is based on the hardening-softening material functions. The hardening functions are consisted of isotropic and kinematic parts. Using the definition of yield surface, material functions and nonlinear elastic behavior, as function of hardening-softening parameters, the constitutive elasto-plastic... 

The purpose of this study is to evaluate the performance of the optimized conditional source-term estimation approach. This model was first implemented in a computational fluid dynamics code, and then the Bernstein expansion was used to optimize it. For validation, two pre-mixed turbulent flames with different turbulence intensity and equivalence ratios were modeled with the optimized and RANS model. The results were obtained for mass fraction of the main and intermediate species, velocity and temperature examined in different sections. In the first flame, the turbulence intensity is low, and the flame is in the flamelet regimes; As a result, the results obtained with the optimized model are... 

The purpose of this study is to investigate a flapping hydrofoil with semi-active kinematics for energy harvesting and evaluate the effect of different dynamic parameters and structures on its performance. The turbulent flow field with Re = 5 × 105 around a NACA 0015 hydrofoil is simulated by URANS method using commercial software and the dynamics of the oscillating hydrofoil is modeled as a mass-spring-damper set in combination with the fluid solver. The sliding mesh method is used for the pitching motion of the hydrofoil with a reduced frequency of 0.14 in combination with the dynamic mesh method for Transitional motion. Initially, the oscillating hydrofoil was considered as a single... 

The importance of aircraft mass properties, including mass, center of gravity position and moments of inertia, and the effect of these parameters on the aircraft performance, stability and control is clearly bright for aviation science specialists. The ability to in-flight estimation of the aircraft mass properties in all flight conditions is a powerful technology for improving conditioned based maintenance systems, automatic flight control systems, flight safety, airplane performance, flight path planning, air traffic management, cooperative and formation flight management, facilitating investigation of aerial accidents caused by uncertainty of the mass properties, and increasing... 

In this research the flexibility of subterranean levels on foundation input motion (FIM), especially rocking component is investigated through parameter analyses. The so-called motion is induced as a result of kinematic soil-structure interaction (SSI). The foregoing interaction reduces the translational component of foundation input motion in rigid embedded foundations when compared to the free-field motion (FFM), as well as yielding rocking component in the foundation. On the other hand, increasing the embedment depth which is equivalent to the presence of subterranean levels in a building decreases the commonly-held “rigid” assumption’s accuracy for the embedded part. Given this effect,... 

Non rigidity of the soil beneath the structure, alters elastic and inelastic response of it. This effect is caused by the soil-structure interaction. The effect of soil-structure interaction is studied in two parts, Kinematic interaction and inertial interaction. Among these, kinematic interaction effects are often assumed to be negligible so that even in existing regulations it has been ignored. While the kinematic part of soil-structure interaction effect could produce a rocking input motion that might be important. In recent years, according to expanding usage of performance based design philosophy, researches on inelastic behavior of the soil-structure systems has been done which is... 

A large number of structures subjected to the seismic loading have been damaged or have experienced failure in different parts such as the pile structure or even in the entire structure due to unanticipated effects of the soil-pile-structure interaction.The complexity of problems regarding the soil-pile-structure interaction is an influencing factor in prediction of the behavior of structure during the earthquakes. In this study, the effect of the interaction on the dynamic response of bridges was investigated using the finite element software ABAQUS. The primary purpose of this study, as previously described, is to study the effects of the soil-structure interaction on a bridge located on a... 

Numerous structures which are involved in seismic soil-pile-structure interaction have been damaged، failure in piles or even collapsed that can’t predict. Because of difficult modeling in soil، pile، structure interaction prediction the response of structure is impossible. In this study with using the finite element Abaqus software tries to understand the effect of soil pile structure interaction in structure response. By using the time history of Elcentro، structure with different boundary conditions were analyzed and the response of them were compared. Models have different boundary condition such as fixed base، pile groups and pile raft. Also in this study the effect of mat in... 

Soil-structure interaction has significant effect on dynamic behavior of the super structure. This effect is usually investigated in two separate parts, i.e., the Kinematic Interaction effect and the Inertial Interaction effect. The first modifies the input ground motion to the foundation as a result of difference in soil and foundation stiffness. The later, i.e., the II effect, introduces the effect of soil flexibility and radiation of waves into the supporting medium on the response of the structure. These effects are usually considered by introducing a replacement oscillator with modified natural period and damping ratio subjected... 

Human body movements are achieved by activating a number of muscles. It has been shown that the central nervous system (CNS) plays the main role in controlling rhythmic activities (including walking, chewing, etc.). However, the way the central nervous system works in controlling different parts of the body has always been discussed due to the excess degrees of freedom to perform certain tasks. Controlling a group of muscles (under the name of muscle synergy analysis) instead of each one of them has been one of the most attractive and efficient recent ideas to better understand the CNS function. Also, a similar concept can be expressed for kinematic synergies (by the degrees of freedom of... 

Background: Degeneration of intervertebral joints due to kinetical alterations after fusion surgery is a prevalent back disorder. While in-vivo studies are limited to medical imaging techniques, in-vitro and in-silico (passive FE modeling) investigations lack the crucial role of muscle forces. Available musculoskeletal modeling studies, not only suffer oversimplification of intervertebral joints, but have some shortcomings in incorporation of the contributing factors (that may alter postoperative kinetics). On the other hand, one of the main shortcomings in the available musculoskeletal models is their inability to account for dynamic effects and modeling transient events. Purpose: 1-... 

Cerebral Palsy is the most common motor disability in childhood. It’s caused by an injury or impaired development of brain. As result, CP children have disability in motor system. All people with cerebral palsy have problem with movement. The symptoms of CP vary from person to person. Therefore, gait analysis was used to investigate those child’s problems and help therapist to find better therapy. Given that, we analyze stance phase of gait cycle of CP children. Also, we calculate and compare variability between traditional development (TD) children and CPs to find a better understanding of how central nerves system (CNS) work. Kinematic Data during walking were collected from 100 CP and TD... 

In this study, we create an evolution function that assesses prosthetic hands in terms of their ability to grasp various objects like a human hand. It is required to evaluate the reachable workspace of prosthetic hands and grasp ability to assess it completely. The first one can be done by using forward kinematics. The Volume of the Grasp Wrench space, one of the grasp qualities indexes, is used to measure the second one. Randomization and grasp taxonomy are used to generalize the grasp quality to indicate the prosthetic hand functionality. Afterward, the created evaluation function is used to specify the importance of each finger and DOF. The results show that the most significant finger is... 

Cable-driven parallel robots (CDPRs) form a class of robotic manipulator in which the actuation end-effector is transmitted through cables. Due to the unique characteristics and advantages of cable transmission, CDPRs have become increasingly studied in recent years. In this thesis, the study of Geometric Analysis and Dynamic Trajectory of a 5-DOF Cable-Suspended Spatial Parallel Robot is investigated. Geometric analysis is corresponds to the workspace on which the robot is designed. The design of cable mechanisms allows the robot to be used with appropriate configuration in various fields such as industry, medicine, etc. The study of CDPR design has been limited due to several reasons.... 

Every year, a significant number of people around the world suffer from anterior cruciate ligament injury. Rapid and low-cost diagnosis of anterior cruciate ligament injury is important to prevent further complications as well as timely treatment. Due to the disadvantages of each diagnostic methods, the development of alternative methods for diagnosing anterior cruciate ligament injury is still of interest to researchers. Meanwhile, several studies have shown that the kinematics of the knee joint are different for injured and healthy anterior cruciate ligament. Due to the capability of inertial sensors for kinematic measurement of joints, their use to diagnose damaged anterior cruciate...