14-07-2012, 03:07 PM
PICK AND PLACE MECHANISM
Literature overview
A robot mechanism is a multi-body system with the multiple bodies connected together. We begin by treating each body as rigid, ignoring elasticity and any deformations caused by large load conditions. Each rigid body involved in a robot mechanism is called a link, and a combination of links is referred to as a linkage. In describing a linkage it is fundamental to represent how a pair of links is connected to each other. There are two types of primitive connections between a pair of links. The first is a prismatic joint where the pair of links makes a translational displacement along a fixed axis. In other words, one link slides on the other along a straight line. Therefore, it is also called a sliding joint. The second type of primitive joint is a revolute joint where a pair of links rotates about a fixed axis. This type of joint is often referred to as a hinge, articulated, or rotational joint..
There are many other ways of locating an end-effecter in three-dimensional space. Three other kinematic structures that allow the robot to locate its end-effecter in three-dimensional space. Although these mechanisms have no analogy with common coordinate systems, they are capable of locating the end-effecter in space, and have salient features desirable for specific tasks. The first one is a so-called SCALAR robot consisting of two revolute joints and one prismatic joint. This robot structure is particularly desirable for assembly automation in manufacturing systems, having a wide workspace in the horizontal direction and an independent vertical axis appropriate for insertion of parts.
The second type, called an articulated robot or an elbow robot, consists of all three revolute joints. This type of robot has a great degree of flexibility and versatility, being the most standard structure of robot manipulators. The third kinematic structure, also consisting of three revolute joints, has a unique mass balancing structure. The counter balance at the elbow eliminates gravity load for all three joints, thus reducing toque requirements for the actuators. This structure has been used for the direct-drive robots having no gear reducer.
Research Methodology
A pick and place robot is a mechanical or virtual intelligent agent that can perform tasks automatically or with guidance, typically by remote control. In practice a robot is usually an electro-mechanical machine that is guided by computer and electronic programming .Robots can be autonomous, semi-autonomous or remotely controlled. The word robot first appeared in the play Rossum's Universal Robots by the Czech writer Karel Capek in 1920.
Robots are used in an increasingly wide variety of tasks such as vacuuming floors, mowing lawns, cleaning drains, building cars, in warfare, and in tasks that are too expensive or too dangerous to be performed by humans such as exploring outer space or at the bottom of the sea.
It is an electric machine which has some ability to interact with physical objects and to be given electronic programming to do a specific task or to do a whole range of tasks or actions. It may also have some ability to perceive and absorb data on physical objects, or on its local physical environment, or to process data, or to respond to various stimuli. This is in contrast to a simple mechanical device such as a gear or a hydraulic press or any other item which has no processing ability and which does tasks through purely mechanical processes and motion.
The first reference in Western literature to mechanical servants appears in Homer's lliad . Asimov is probably best remembered for his science-fiction stories and especially those about robots, where he placed robots and their interaction with society at the center of many of his works. Asimov carefully considered the problem of the ideal set of instructions robots might be given in order to lower the risk to humans, and arrived at his three laws of Robotics: a robot must obey orders given to it by human beings, except where such orders would conflict with the First Law; and a robot must protect its own existence as long as such protection does not conflict with the First or Second Law. These were introduced in his 1942 short story "Runaround", although foreshadowed in a few earlier stories. Later, Asimov added the Zeroth Law: "A robot may not harm humanity, or, by inaction, allow humanity to come to harm"; the rest of the laws are modified sequentially to acknowledge this.
The 'SCARA' style robot is a four degree-of-freedom robotic arm that can be used to pick and place small parts on a production line. It has been designed as an appliance; it is totally self-contained– the user can plug the power cord into a standard AC socket and the unit is operational. In a typical application it can replace the human operator in feeding industrial presses with discrete components. Its low cost ensures early return on investment and its modular design with a minimum number of components promotes reliability. It can be easily integrated into automation systems as it provides a wide range of auxiliary control interfaces for digital and analog inputs, digital outputs, pneumatics, and stepper control. The programming interface uses PLC style ladder logic eliminating the need to learn a programming language.
Compact and totally self-contained to minimize installation and redeployment effort and cost
Modular intelligent joint actuators, each powered by a fixed point DSP controller
PLC-style programming interface to minimize training and technical support
Auxiliary control interfaces for system integration and user customization.
Conclusion:-
Hence, it made me to come to the conclusion that PICK AND PLACE mechanism is a thing that made me to about ROBOTS and all. It is a robotic mechanism which is used to pick something and at a place which is far away or at a position where a man’s hand can’t reach.
Future Scope
MOBILE ROBOT:-
Mobile robots have the capability to move around in their environment and are not fixed to one physical location. An example of a mobile robot that is in common use today is the automated guided vehicle or automatic guided vehicle (AGV). An AGV is a mobile robot that follows markers or wires in the floor, or uses vision or lasers. AGVs are discussed later in this article.
Mobile robots are also found in industry, military and security environments. They also appear as consumer products, for entertainment or to perform certain tasks like vacuum cleaning. Mobile robots are the focus of a great deal of current research and almost every major university has one or more labs that focus on mobile robot research.
Modern robots are usually used in tightly controlled environments such as on assembly lines because they have difficulty responding to unexpected interference. Because of this most humans rarely encounter robots. However domestic robots for cleaning and maintenance are increasingly common in and around homes in developed countries. Robots can also be found in military applications.
INDUSTRIAL ROBOTS:-
Industrial robots usually consist of a jointed arm (multi-linked manipulator) and an end effector that is attached to a fixed surface. One of the most common type of end effector is a gripper assembly ."an automatically controlled, reprogrammable, multipurpose, manipulator programmable in three or more axes, which may be either fixed in place or mobile for use in industrial automation applications."
MILITARY ROBOTS:-
Some experts and academics have questioned the use of robots for military combat, especially when such robots are given some degree of autonomous functions. There are also concerns about technology which might allow some armed robots to be controlled mainly by other robots. The US Navy has funded a report which indicates that as military robots become more complex, there should be greater attention to implications of their ability to make autonomous decisions. One researcher states that autonomous robots might be more humane, as they could make decisions more effectively. However, other experts question this.
Some public concerns about autonomous robots have received media attention. One robot in particular, the EATR, has generated concerns over its fuel source as it can continually refuel itself using organic substances. Although the engine for the EATR is designed to run on biomass and vegetation specifically selected by its sensors which it can find on battlefields or other local environments, the project has stated that chicken fat can also be used.