MEANING OF ROBOT TECHNOLOGY
MEANING OF ROBOT TECHNOLOGY
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Man, since very long, has been thinking of building a mechanical version of himself which led to the introduction of robots in early sixties. The word robot has its origin in the Czech word ‘robota’ meaning ‘forced labour’. According to the Robotics International Division of the Society of Manufacturing Engineering, “Industrial robot is a reprogrammable multifunctional manipulator designed to move materials, parts, tools or specialized devices through variable programmed motions for the performance of variety of task.” However, commonly robot denotes all those electro mechanical machines which can be programmed to perform manual tasks. The robots wholly or in part imitate man-sometimes his appearance, sometimes his actions and sometimes both. Three features that turn a computer into a robot are: (i) sensors which catch information from the environment; (ii) microprocessors which convert that information into new forms; and (iii) actuators which control the energy needed to change the environment.
Robotics: It is the science which deals with the study of kinetmatics, dynamics and functioning of various components of a robot. The word “Robotics” was invented by science fiction writer Isaac Asimov, who propounded the famous three laws of robots as given below:
(i) The robot may not injure a human being or through an action allow a human being to come to harm.
(ii) A robot must obey the orders given to it by the human beings except where those orders would violate the first law.
(iii) A robot must protect its own existence except where that would violate the first and second laws.
DEVELOPMENT OF ROBOT TECHNOLOGY
Robot is a result of ‘mechtronics’ (synthesis of electronics with mechanical aspect) revolution. Robot (or computer numerical control or CNC) made a slow start in the 1960s in the world. The first numerical control (NC) was developed in India in 1973. But this machine had imported NC control. In advanced countries CNC technology was developed by mid 1970s whereas in India its development and application has been rather slow. The two institutions which are mainly working in the field of robots are-Central Machine Tool Institute (CMTI) on research and design and the Hindustan Machine Tools (HMT) on manufacturing. Besides these two institutions the other groups working on robotics include IIT Madras, IISc Bangalore, Hyderabad Science Society and a few engineering colleges.
APPLICATIONS OF ROBOT
Industrial application of robots is favoured because of their untiring nature, predictability, precision, reliability and ability to work in relatively hostile environment such as toxic chemicals industries, assembly of explosives, deep sea, high altitude and mountainous terrains, cold climates and nuclear reactors. Besides this robots frequently increase throughput and productivity, I improve overall product quality, allow replacement of human labour in monotonous and of course in hazardous tasks. Many save on material and energy and throughout they have sufficient flexibility and they may be used for medium or even small batch production which traditionally have not been susceptible to automation.
Industrial applications: (i) Manufacturing-debussing, die casting, fitting, forging, investment casting, plastic moulding, press working; (ii) Loading, unloading and movement of parts- machine loading and unloading, moving of parts; (iii) Welding and cutting-arc welding, spot welding, laser cutting, water jet cutting; (iv) Painting-spray painting and coating; (v) Design and assembly-product dressing, assembly sequencing, inspection, layout analysis and evaluation assembly; (vi) Other processes-heat treatment, packing, palletising, stacking.
Non-industrial applications: This includes marine work, space work, bionomics, farm work, fun, helping the disabled, lab work, mining, nuclear work, security guarding, sheep shaving, simulation, warehouse, microsurgery etc.
TYPES OF ROBOTS
Robots can be found in the manufacturing industry, the military, space exploration, transportation, and medical applications. Below are just some of the uses for robots.
Ø Industrial Robots
Though not humanoid in form, machines with flexible behaviour and a few humanlike physical attributes have been developed for industry. The first stationary industrial robot was the programmable Unimate, an electronically controlled hydraulic heavy-lifting arm that could repeat arbitrary sequences of motions. It had the unsavoury task (for humans) of removing and stacking hot metal parts from a die-casting machine. Unimate arms continue to be developed and sold by licensees around the world, with the automobile industry remaining the largest buyer.
More advanced computer-controlled electric arms guided by sensors were developed at the Massachusetts Institute of Technology (MIT) and at Stanford University, where they were used with cameras in robotic hand-eye research. Called PUMA (Programmable Universal Machine for Assembly), they have been used since 1978 to assemble automobile subcomponents such as dash panels and lights. PUMA was widely imitated, and its descendants, large and small, are still used for light assembly in electronics and othei industries. Since the 1990s small electric arms have become important in molecular biology laboratories, precisely handling test-tube arrays and pipetting intricate sequences of reagents.
Ø Robots in Manufacturing
Today most robots are used in manufacturing operations; the applications can be divided into three categories: (1) material handling, (2) processing operations, and (3) assembly and inspection.
Material-handling applications include material transfer and machine loading and unloading. Material-transfer applications require the robot to move materials or work parts from one location to another. Many of these tasks are relatively simple, requiring robots to pick up parts from one conveyor and place them on another. Other transfer operations are more complex, such as placing parts onto pallets in an arrangement that must be calculated by the robot. Machine loading and unloading operations utilize a robot to load and unload parts at a production machine. This requires the robot to be equipped with a gripper that can grasp parts. Usually the gripper must be designed specifically for the particular part geometry.
In robotic processing operations, the robot manipulates a tool to perform a process on the work part. Examples of such applications include spot welding, continuous arc welding, and spray painting. The robot positions a spot welder against the automobile panels and frames to complete the assembly of the basic car body. Arc welding is a continuous process in which the robot moves the welding rod along the seam to be welded. Spray painting involves the manipulation of a spray-painting gun over the surface of the object to be coated. Other operations in this category include grinding, polishing, and routing, in which a rotating spindle serves as the robot’s tool.
The third application area of industrial robots is assembly and inspection. The use of robots in assembly is expected to increase because of the high cost of manual labour common in these operations. Since robots are programmable, one strategy in assembly work is to produce multiple product styles in batches, reprogramming the robots between batches. An alternative strategy is to produce a mixture of different product styles in the same assembly cell, requiring each robot in the cell to identify the product style as it arrives and then execute the appropriate task for that unit.
The design of the product is an important aspect of robotic assembly. Assembly methods that are satisfactory for humans are not necessarily suitable for robots. Using a screw and nut as a fastening method, for example, is easily performed in manual assembly, but the same operation is extremely difficult for a one-armed robot. Designs in which the components are to be added from the same direction using snap fits and other one-step fastening procedures enable the work to be accomplished much more easily by automated and robotic assembly methods.
Inspection is another area of factory operations in which the utilization of robots is growing. In a typical inspection job, the robot positions a sensor with respect to the work part and determines whether the part is consistent with the quality specifications.
In nearly all industrial robotic applications, the robot provides a substitute for human labour. There are certain characteristics of industrial jobs performed by humans that identify the work as a potential application for robots: (1) the operation is repetitive, involving the same basic work motions every cycle; (2) the operation is hazardous or uncomfortable for the human worker (e.g., spray painting, spot welding, arc welding, and certain machine loading and unloading tasks); (3) the task requires a work part or tool that is heavy and awkward to handle; and (4) the operation allows the robot to be used on two or three shifts.
Mobile industrial robots also first appeared in 1954. In that year a driverless electric cart, began pulling loads around a grocery warehouse. Such machines, dubbed AGVs (Automatic Guided Vehicles), commonly navigate by following signal-emitting wires entrenched in concrete floors. In the 1980s AGVs acquired microprocessor controllers that allowed more complex behaviours than those afforded by simple electronic controls. In the 1990s a new navigation method became popular for use in warehouses: AGVs equipped with a scanning laser triangulate their position by measuring reflections from fixed retro-reflectors.
Ø Robots on Earth
Typical industrial robots do jobs that are difficult, dangerous or dull. They lift heavy objects, paint, handle chemicals, and perform assembly work. They perform the same job hour after hour, day after day with precision. They don’t get tired and they don’t make errors associated with fatigue and so are ideally suited to performing repetitive tasks. The major categories of industrial robots by mechanical structure are:
- Cartesian robot /Gantry robot: Used for pick and place work, application of sealant, assembly operations, handling machine tools and arc welding. It’s a robot whose arm has three prismatic joints, whose axes are coincident with a Cartesian coordinator.
- Cylindrical robot: Used for assembly operations, handling at machine tools, spot welding, and handling at die casting machines. It’s a robot whose axes form a cylindrical coordinate system.
- Spherical/Polar robot: Used for handling at machine tools, spot welding, die casting, fettling machines, gas welding and arc welding. It’s a robot whose axes form a polar coordinate system.
- SCARA robot: Used for pick and place work, application of sealant, assembly operations and handling machine tools. It’s a robot which has two parallel rotary joints to provide compliance in a plane.
- Articulated robot: Used for assembly operations, die casting, fettling machines, gas welding, arc welding and spray painting. It’s a robot whose arm has at least three rotary joints.
- Parallel robot: One use is a mobile platform handling cockpit flight simulators. It’s a robot whose arms have concurrent prismatic or rotary joints.
Industrial robots are found in a variety of locations including the automobile and manufacturing industries. Robots cut and shape fabricated parts, assemble machinery and inspect manufactured parts. Some types of jobs robots do: load bricks, die cast, drill, fasten, forge, make glass, grind, heat treat, load/unload machines, machine parts, handle parts, measure, monitor radiation, run nuts, sort parts, clean parts, profile objects, perform quality control, rivet, sand blast, change tools and weld.
Outside the manufacturing world robots perform other important jobs. They can be found in hazardous duty service, CAD/CAM design and prototyping, maintenance jobs, fighting fires, medical applications, military warfare and on the farm.
A robot agricultural harvester named Demeter is a model for commercializing mobile robotics technology. The Demeter harvester contains controllers, positioners, safeguards, and task software specialized to the needs commercial agriculture.
Some robots are used to investigate hazardous and dangerous environments. The Pioneer robot is a remote reconnaissance system for structural analysis of the Chernobyl Unit 4 reactor building. Its major components are a teleoperated mobile robot for deploying sensor and sampling payloads, a mapper for creating photorealistic 3D models of the building interior, a coreborer for cutting and retrieving samples of structural materials, and a suite of radiation and other environmental sensors.
Ø Robots in Space
Space-based robotic technology at NASA falls within three specific mission areas: exploration robotics, science payload maintenance, and on-orbit servicing. Related elements are terrestrial/commercial applications which transfer technologies generated from space telerobotics to the commercial sector and component technology which encompasses the development of joint designs, muscle wire, exoskeletons and sensor technology.
Today, two important devices exist which are proven space robots. One is the Remotely Operated Vehicle (ROV) and the other is the Remote Manipulator System (RMS). An ROV can be an unmanned spacecraft that remains in flight, a lander that makes contact with an extraterrestrial body and operates from a stationary position, or a rover that can move over terrain once it has landed. It is difficult to say exactly when early spacecraft evolved from simple automatons to robot explorers or ROVs. Even the earliest and simplest spacecraft operated with some preprogrammed functions monitored closely from Earth. One of the best known ROV’s is the Sojourner rover that was deployed by the Mars Pathfinder spacecraft.
The most common type of existing robotic device is the robot arm often used in industry and manufacturing. The mechanical arm recreates many of the movements of the human arm, having not only side-to-side and up- and-down motion, but also a full 360-degree circular motion at the wrist, which humans do not have. Robot arms are of two types. One is computer-operated and programmed for a specific function. The other requires a human to actually control the strength and movement of the arm to perform the task. To date, the NASA Remote Manipulator System (RMS) robot arm has performed a number of tasks on many space missions-serving as a grappler, a remote assembly device, and also as a positioning and anchoring device for astronauts working in space.
Ø Robot Toys
Lack of reliable functionality has limited the market for industrial and service robots (built to work in office and home environments). Toy robots, on the other hand, can entertain without performing tasks very reliably, and mechanical varieties have existed for thousands of years. In the 1980s microprocessor-controlled toys appeared that could speak or move in response to sounds or light. More advanced ones in the 1990s recognized voices and words. In 1999 the Sony Corporation introduced a doglike robot named AIBO with two dozen motors to activate its legs, head, and tail, two microphones, and a colour camera all coordinated by a powerful microprocessor. More lifelike than anything before, AIBOs chased coloured balls and learned to recognize their owners and to explore and adapt.
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