Monday, January 24, 2011

ROBOTICS



TABLES OF CONTENTS:-

· Introduction.

· History.

· Advantages and disadvantages of robotics.

· Robots components.

· Robot joints.

· Robots workspace.

· Robotic applications: current and future.

· Robots application in future.

INTRODUTION:-

Robots are those workers, which have been made by us for several works; we want to do without our labour. It is also defined as the electrical machine which does several works for us.

Robotics is the art knowledge, base and the know-now of designing applying and using robots in human endeavors. Robotics system consists of not just robots, but also other device and system that are used together with the robots to perform the necessary tasks. Robots may be used in manufacturing environment, in underwater and space exploration, for aiding the disabled, or even for fun. In any capacity, robobos can be useful, but need to be programmed and controlled. Robotics is an interdisciplinary subject that benefits from mechanical engineering, electrical and electronic engineering, and computer science and many other disciplines.

Mankind has always strived to give the qualities to it’s artifacts in an attempt to find substitutes for himself to carry out his orders and also to work in a hostile environment. The popular concept of a robot is of a machine that looks and works like a human being. This humanoid concept has been inspired by science fiction stories and films in 12­­th century. The industrial robot of today may not look the least bit like a human being although all the research is directed to provide more and more anthropomorphic and human-like features super-human capabilities.

The subject of robotics covers many different areas. Robots alone are hardly ever useful. They are used together with other devices, peripherals, and other manufacturing machines. They are generally integrated into a system, which as a whole is designed to perform a task or do an operation.

HISTORY:-

In 1921 for the first time the word “ROBOT” was introduced by “CZECH WRITER, KAREL CAPEK”, in his drama. It was derived from Czech word robota means “forced labourer”. Isaac Asimov the well-known Russian science fiction writer, coined the word robotics in his story “Runaround”, published in 1942, to denote the science devoted to study of robots.

Disregarding the early machines that were made to mimic humans & their action and concentrating on the recent history, one can see a close relationship between the state of industry, the revolution in numeric computer control of machinery, space exploration and the vivid imagination of creative people. The first “ROBOTS” were controlled by strips of papers with holes, which electric eyes could detect and which controlled the robots movements. As industry improved, the strip of paper gave way to managetic tapes, memory devices and pc’s. The following is a summary of events have marked changes in the direction of this industry:-

  • 1972: IBM worked on a rectangular coordinate robot for internal use. It eventually developed the IBM 7565 for sale.
  • 1973: Cincinnati MilacronTM introduced the T3 model robot, which became very popular in industry.
  • 1978: The first PUMA robot was shipped to GM by 1922: Czech author Karel Capek wrote a story called “Rossum’s Universal Robots” and introduced the word “RABOTA”.
  • 1956: George Devol developed the magnetic controller, a playback device. Eckert and Mauchley built the ENIAC computer at the University of Pennsyvania.
  • 1952: The first NC machine was built at MIT.
  • 1954: George Devol developed the first programmable robot.
  • 1955: Devanit and Hartenberg developed homogeneous transformation matrices.
  • 1961: U.S. patent 2,988,237 was issued to George Devol for “programmed Article Transfer”, a basis for unimate books.
  • 1967: Unimate TM introduced the MARK IITM robot. The first robot was imported to Japan for paint-spraying applications.
  • 1968: An intelligent robot called Shakey was built at Stanford Research institute.(SRI)
  • Unimation.
  • 1982: GM and Fanuc of Japan signed an agreement to build GM Fanuc robots. Westinghouse bought Unimation, which was later, sold to Staubli of Switzerland.
  • 1983: Robotics became a very popular subject, both in industry, as well as academia. Many programs in the nation started teaching courses in robotics.
  • 1990: Cincinnati Milacron was acquired by ABB of Switzerland. Most small robot manufactures went out of the market. Only a few large companies, which primarily produce industrial robots, remained.

ADVANTAGES AND DISADVANTAGES OF ROBOTICS:-

Robotics is a science of new era architecture of creating the workers, which does our works without any objections. So today everyone is going through it, it has a big subject for a new generation; so its advantages and disadvantages are discussed below;

  • Robotics and automation can, in many situations, increase productivity, safety, efficiency, quality, and consistency of products.
  • Robots can work in hazardous environment without the need for life support, comfort, or concern about safely.
  • Robots need no environment comfort, such as lighting, air conditioning, ventilation, and noise protection.
  • Robots work continuously without experiencing fatigue or boredom, do not get mad, do not have hangovers, and need no medical insurance or vaccinations.
  • Robots have repeatable precision at all times, unless something happens to them or unless they wear out.
  • Robots can be much more accurate than humans typical linear accuracies are a few thousands of an inch. New wafer-handling robots have micro inch accuraciers.
  • Robots lack capability to respond in emergencies, unless the situation is predicted and the response is included in the system.
  • Robots are costly, due to ;

*Initial cost of equipment.

*Installation costs.

*Need for peripherals.

*Need for training.

*Need for programming.

ROBOTS COMPONENTS:

A robot, as a system, consists of the following elements, which are integrated together to form a whole:-

1. Manipulator or rover:-

This is the main body of the robot and consists of the links, the joints, and other structural elements of the robot. Without other elements, the manipulator alone is not a robot.

2. End effector:-

This is the part that is connected to the last joint (hand) of a manipulator, which generally handles objects, makes connection to other machines, or performs the required tasks. Robots manufactures generally do not design or sell end effectors. In most cases, all they supply is a simple gripper. Generally, the hand of a robot has provisions for connecting specialty end effectors that are specifically designed for a purpose. This is the job of a company’s engineers or outside consultants to design and install the end effector on the robot and to make it work for the given situation. A welding torch, a paint spray gun, a glue-laying device, and a parts handler are but a few of the possibilities.

3. Actuators:-

Actuators are the “muscles” of the manipulator. Common types of actuators are servomotors, stepper motors, pneumatic cylinders, and hydraulic cylinders. There are also other actuators that are more novel and are used in specific situations.

4. Sensors:-

Sensors are used to collect information about the internal state of the robot or to communicate with the outside environment. As in humans, the robots controller needs to know where each link of the robot is in order to know the robot’s configuration.

5. Controller:-

This controller is rather similar to your cerebellum, and although it does not have the power of your brain, it still controls your motions. The controller receives its data from the computer, controls the motion of the actuators, and coordinates the motions with the sensory feedback information. Suppose that in order for the robot to pick up a part from a bin, it is necessary that its first joint be at 350.

6. Processor:-

The processor is the brain of the robot. It calculates the motions of the robot’s joints, determines how much and how fast each joint must move to achieve the desire location and speeds, and overseas the coordinate actions of the controller and the sensors. The processor is generally a computer, but is dedicated to a single purpose.

7. Software:-

There are perhaps three groups of software that are used in a robot. One is the operating system, which operates the computer. This second is the robotic software, which calculates the necessary motions of each joint based on the kinematic equations of the robot. This information is sent to the controller. This software may be at many different levels, from machine language to sophisticated languages used by modern robots.

ROBOT JOINTS:-

Robots may have different types of joints, such as linear, rotary, sliding, or spherical. Although spherical joints are common in many system, since they posses multiple degrees of freedom, and thus, are different to control, spherical they posses multiple degrees of freedom, and thus, are difficult to control, spherical joints are not common in robotics, except in research. Most robots have either a linear (prismatic) joint or a rotary (revolute) joint.

Prismatic joints are linear; there is no rotation involved. They are either hydraulic or pneumatic cylinders, or they are linear electric actuators. These joints are used in gantry, cylindrical, or similar joint configurations.

Revolute joints are rotary, and although hydraulic and pneumatic rotary joints are common, most rotary joints are electrical driven, either by steeper motors or, more commonly, by servomotors.

ROBOT WORKSPACE:-

Depending on their configuration and the size of their links and wrist joints, robots can reach a collection of points called workspace. The space of the workspace for each robot is uniquely related to its characteristics. The workspace may be found mathematically by writing equations that define the robot’s links and joints and including their limitations, such as ranges of motions for each joint. Alternatively, the workspace may be found empirically, by moving each joint through it’s range of motions and combining all the space it can reach and subtracting what is cannot reach. When a robot is being considered for a particular application, it’s workspace must be studied to ensure that the robot will be able to reach the desired points. For accurate workspace determination, please refer to manufactures’ data refers.

ROBOTIC APPLICATION: CURRENT AND FUTURE:-

In it’s relative infancy, the state of the art of robotic applications is, in some ways, paralleling the development of digital computers. When they were first introduced, computers were used for tasks that had previously been performed the people. This was a natural application, for it was obvious that the new device could perform such jobs much faster and even more reliably than people could perform them. However, as time progressed, it was recognized that tasks excessive manpower and/or time requirement were now possible tom attempt. Thus problems that was “not practical” to solve were handled with relative ease. Besides being able to solve such problems, it became apparent that there were many applications for the computers that had never been thought of before its development. In a sense, what happened was that people took of their “blinders” and allowed their imaginations free reign. The result of this has been that computers are now applied in many areas other than the more traditional “number crunching” that was initially envisioned as the major use. The fields of control (of large-scale system), learning and teaching devices, handling of large data bases, and artificial intelligence come to mind, to name but a few nontraditional applications.

The first applications of the robot have been in areas where human beings have tradionally been working. Although there have been some significant technological advances in the design of robots since the first one was developed more than 20 years ago, the manipulators currently being manufacture are, as a general rule, rather simple. As a result, the state of art in robot applications is probably where the computer was when it was used primarily for “computing”. It has taken a much longer time for the blinders to be taken off when talking about robots than it did with computers. One can cite a number of possible reasons for this , including the problems of recessions, fear of people losing their jobs, and the lack of the major scientific breakthrough comparable to the development of the transistors and later, the integrated circuit. Also, some of the first big users and/or developers of computers were in government, the military, and the university. These three entities, which were responsible, for developing many of the unique computers applications, have only recently entered the robot field in a large way. The industrial sector has been the major user, and as might least significantly reduced the risk taking required to produce new ideas and developmental research by manufactures. The recent emergence of robot programs supported by both the military and state and federal government may indicate that this situation is beginning to change, however. As robotic applications will begin to appear which will, in part, contributed to the development of the fully automated factory or the factory of future.

ROBOT APPLICATIONS IN FUTURE:-

Today in this changing world every one wants someone who will do their work without any pay. He will work day/night without any hesitation so we are creating “robots”. Robots are the creations of human beings which are used in every work in this world such as; in space projects, underwater research, and other projects.

A number of studies have been made over the last few years which try to anticipate some of the new applications of robots. One common thread in these studies is that advanced application will almost always depend on the development of sophisticated, dependable, and low-cost external sensors. The “deaf, dumb, blind and tactile less” robot of the mid-1980s is limited in its ability to perform complex tasks. Thus, unless sensor-based e robots are developed, applications will remain fairly simple.

The medical applications of robots are certainly many years away from reality. For example, the “six-million-dollar man” will be possible only with the development of real-time signal-processing techniques that permits the desired signals emanating from the brain and transmitted over nerves to be separated from muscle noise so as to control the transmitted prosthesis reliably. In addition, the power pack for such appendages will have to be small, light and powerful, and tactile-sensing elements with resolutions approximately those of the human hand will be necessary.

The ability of robot to carry out surgical producers or examinations will depend on the development of a variety of external sensors and real-time computer processing techniques. More important, the robot will have to be intelligent in order to make rapid decisions based on current sensory information. It is certain that a set of preprogrammed actions will be totally unsatisfactory for such applications. This implies that significant advances in artificial intelligence (AL) will be required. It should be noted, however, that a unimation rosurgery. The robot’s controller was interfaced to a computerized tomography (CAT) system which determined and outputted the desired points in space to which the robot was required to move.

The military is currently looking at robots for use in a variety of areas. For example, the air force and navy are both interested in mobile firefighters.


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