Sharif Digital Repository

Coordinate motion is a considerable phenomenon in biology and very powerful tool for leading and controlling a group of robots. In recent years, robotic becomes a helpful technology for acompilishing in works which is impossiple for human, such as working in toxic environments. In this project, we introduce coordinate motion problems which are applicable in multi-agent systems, and we also present suitable control algorithms for solving this problem. In other word, we use potential field method to model coordinate motion. We propose a three-cycle robot as an agent, such that it has two nonholonomic constraints. Designing an algorithm for solving coordinate motion problems, we propose these... 

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... 

In this thesis control of wheeled mobile manipulators for cooperative object transportation is investigated. Full dynamic model of a mobile manipulator with a three wheeled mobile base and a three DOF manipulator is derived using Gibbs-Appell method. Input-output linearization technique is used to control individual robots. Transporting the object is divided into two steps, first robots use a decentralized behavior-based method to approach and surround the object. Then virtual structure method is used to control the robots to transport the object cooperatively. Simulation results with three robots handling an object are presented to show the effectiveness of proposed method  

Wheeled mobile robots form a subcategory of mobile robots and are usually accompanied with geometric constraints on their velocities. These constraints do not allow the robots to move in any path that only does not collide with obstacles, in order to move from one point to another. On the other hand, the nonlinear nature of these systems make their control difficult. A general approach in motion planning and control for mobile robots is using standard forms equivalent to their state equations; Usually, solving motion planning and control problems for these forms is easier than that of the original system. Also,the mentioned problems are more prospective to have a systematic solution for... 

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... 

Nonholonomic constraints are a vast portion of constraints that happen in variety of dynamics applications such as robotics and control. In this project we present a new form of D’Alembert’s principle and employ it to generalize classical methods of Analytical Dynamics. It results in a new formulations which can be implemented to solve constrained dynamical systems either holonomic or nonholonomic. These formulations do not have any restrictions on the order of the nonholonomic constraints and can analyze high order nonholonomic constraints (HONCs) as well as first order constraints. In addition using these formulation one can find equations of motion of nonholonomic systems without... 

The main purpose of the present thesis is to establish a decentralized controller for some car–like multi robots to follow and hunt moving targets. Robots are very similar to actual cars considering geometric dimensions, mass and moment of inertia and so on; and outputs of the controller are steering-wheel and driving-wheel torques appropriately. Dynamics of the moving target is so that it escapes from the robots. Robots are equipped with antenna for getting wireless sensory signals, including range and bearing sensors. Kalman filter is used for estimation the target relative position and speed and robots state variables. The controller is designed for doing the above mentioned group... 

In recent years formation control of autonomous vehicles has been a well-studied topic, and the attention has shifted from the control of a single mobile robot to the control of multiple mobile robots because of the advantages a team of robots offer, such as increased efficiency, robustness against fault and damaging, and more systematic approaches to tasks like search and rescue operations, automated highways, survey and patrols, military missions, moving large objects and moving a large number of objects. Formation control means the problem of controlling the relative position and orientation of the mobile robots in a group according to some desired pattern for executing a given task. In...