MANIPULATOR ( DESIGN AND CONTROL )
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Date
2011
Authors
Ahmad Salah
Anass Qrayeb
Fakhry Abu Zahra
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Abstract
Project Overview Robots are machines that have interested the general population throughout history. In general, they are machines or devices that operate automatically or by remote control. Clearly people have wanted to use such equipment since simple devices were developed. The word "Robot" comes from the Czech word "Robota", which means that "Labor doing compulsory manual works without receiving any remuneration or to make things manually". Because of wide usage of robots in factories of deferent kind of production operations and the importance of robotics science in our life in field of medical and other respects. The most common manufacturing robot is the robotic arm. A typical robotic arm was made up of seven metal segments, joined by six joints. But in our project, it composed of three metal segments, joined by three joints. The computer controls the robot by rotating individual step motors connected to each joint (some larger arms use hydraulics or pneumatics). Unlike ordinary motors, step motors move in exact increments. This allows the computer to move the arm very precisely, repeating exactly the same movement over and over again. The project is divided into chapters that deal with this kind of robots: The first chapter is intended to give the reader an overview of the subject matter and to highlight the major issues to be discussed in the next chapters. Chapter two, in this chapter, we first look at some of the history behind the robot, so we talked about the history of robotics, and about the development of its industry over the last few years, until the present time. Then we spoke on the applications of robots in various fields of life, and the industrial revolution caused by the terrible and rapid development in the manufacture of robots. Chapter three, this chapter talked about the dynamic of the manipulator, Kinematics and kinetic can be considered as the essential part in the design of a robot, either linear or angular is the most critical part in robot design. Then Denavit Hartenberg parameters will introduced generally, and specifically for our manipulator. After that the nomenclature of "Jacobians" will introduced, and its importance in force, torque, and moments calculations. The forces at each link will distinguish, in order to select the proper required parts. The torque at each link joint will calculated essentially to provide the required motor's torque to the ink to withstand with the load propagation and the link's inertia itself. Chapter four, this chapter concern with methods of computing a trajectory in multidimensional space which described motion of a manipulator. Trajectory here refers to a time history of position, velocity, and acceleration for each degree of freedom. The problem, which this chapter solves, is the human interface of how to specify the trajectory or path through the space in a good, smooth path. This problem was resolved by using computers, in which the user must only specify the position and orientation of the specified goal. The cubic function method is able to use in this situation, since the main objective from this study is to develop a path or trajectory for a manipulator or a robot, in the way of smooth movement. Chapter five, this chapter talked about the motor and actuators, in constructing our arm, three stepper motors and gears are to be used since our structure is a three dimensional structure. There is a stepper motor at the base, which allows for circular movement of the whole structure; another at the shoulder which allows for upward and downward movement of the arm; while the last stepper motor at the wrist allows for the picking of objects by the end effector. Conclusion In conclusion, for our final project, we wanted to do something in robotics because we thought it would be cool. So we want to do a robotic arm project. Since a project on robotic arm was done last year, we wanted to take a different approach. Our project plan was to be able to train the arm to do something and have it repeat the movement automatically. The movement was also to be optimized in software so that it tries to use best path possible between two points.