Sharif Digital Repository

Currently, precision positioning plays a pivotal role in technology. The need for accurate positioning in applications such as robotics, optoelectronics and micro and nano technology increases day by day. To begin with, we wanted to make a miniature prototype of a micro actuator but in this regard, we are faced with several problems. Some major problems were the high cost of this prototype plus the fact that we did not have the necessary equipment with acceptable resolution for making such a system, so we decided to decrease the scale and build it in micro scale which is accessible for us. The main idea and design of this micro actuator is by Mrs. Akbari. During this project, the researcher... 

Satelites formation which is a specic spatial conguration of satellites, is of great importance in design and control of satellite systems. Reducing the required power to maintain that conguration, while imposing complicated dynamics on the system, connecting satelites through tethers has recently attracted researchers' attention. Developing a new model based on which the motion of the satellite formation will be expressed through simple equations, followed by the study of how the tether length control participates in the orientation control of the system, are the principal aims of current research. First, a new model is proposed for a group of tethered satellite for- mations, and based on... 

Swarm is coordinated group action that usually done with little communication among its members. Using several simple members instead of the complicated ones reduces cost, simplifies system and increases the reliability. On the other hand, the mission can be done faster. This thesis is done in two general sections; theoretical and experimental parts. At first some important missions are simulated in MATLAB/Simulink such as aggregation, dispersion, flocking, obstacle detection, obstacle collision avoidance and orbiting around the obstacle. Orbiting around the obstacle is simulated formation flying and a constellation of satellites (such as GPS systems). The methodology is artificial potential... 

In this research application of Ionic Polymer Metal Composite (IPMC) as actuator in a deformable ring capable of locomotion is studied. Such a deformable ring moves as a result of gravitational force acting on its body when its shape changes. A deformable robot made of IPMC can be used in exploration, search and rescue missions in future, where using conventional robots with rigid bodies and actuators is impossible. Large deformation induced by small stimulating voltage, low stiffness and the sensing characteristics that in future work can be used in feedback control make IPMC a good choice for such an application. In this work first a model for IPMC is introduce that can be used in... 

This study is about real-time hybrid motion planning for autonomous UAVs in dynamic environments. The algorithm is based on system dynamic quantization to trim trajectories and maneuvers, constructing a library of primitives which guarantee the controllability of the system. Random algorithms introduced in literature of motion planning have an offline phase, reducing the computational complexity of online phase. By using dynamic quantization, we have achieved a new totally online algorithm, increasing the probability of finding a solution. Dynamic programming is the core of this algorithm, instead of offline calculations in before random algorithms. In order to decrease the exponential... 

Swarm robotics has attracted a lot of researches in recent decades due to its ability to overcome complexities despite of simple hardware used in each member of swarm. Developing control algorithms which can address connection, consensus and average consensus, position control, formation and swarm movement, is one of the main problems in the study of multi-agent systems and swarm robotics. Even though such methods have been developed and used by researchers for a few years, theoretical and operational issues still exist in the use of robotic swarms. For example, in leader-follower method, presence of repellent coordinator agent results in disruption in movement of other agents. Also... 

The aim of this project is decentralized control of a group of robots (swarm robots); such that the aggregation maneuver, leader following, Identification and imaging the target, will be performed so good as to make a three-dimensional model of the target from these images. Swarm robots consist of a number of similar and limited features robots which interaction in a group of robots, will lead to special features for the group. Any agent of group decides what to do only with its local information from the environment. Swarm robots are more applicable for the jobs in which a distributed perception from the environments needed, for example space exploration and military operations.In this...