Robotics

Robotics is the science and technology of robots, their design, manufacture, and application. Robotics requires a working knowledge of electronics, mechanics and software, and is usually accompanied by a large working knowledge of many subjects. A person working in the field is a roboticist.

• Although the appearance and capabilities of robots vary vastly, all robots share the features of a mechanical, movable structure under some form of autonomous control. The structure of a robot is usually mostly mechanical and can be called a kinematic chain (its functionality being akin to the skeleton of the human body). The chain is formed of links (its bones), actuators (its muscles) and joints which can allow one or more degrees of freedom.
  
• Most contemporary robots use open serial chains in which each link connects the one before to the one after it. These robots are called serial robots and often resemble the human arm. Some robots, such as the Stewart platform, use closed parallel kinematic chains. Other structures, such as those that mimic the mechanical structure of humans, various animals and insects, are comparatively rare.
  
• However, the development and use of such structures in robots is an active area of research (e.g. biomechanics). Robots used as manipulators have an end effector mounted on the last link. This end effector can be anything from a welding device to a mechanical hand used to manipulate the environment.

Etymology

• The word robotics was first used in print by Isaac Asimov, in his science fiction short story "Runaround", published in March 1942 in Astounding Science Fiction. However, Asimov was unaware that he was coining a new term. The design of electrical devices is called electronics, so the design of robots is called robotics.
  
• Before the coining of the term, however, there was interest in ideas similar to robotics (namely automata and androids) dating as far back as the 8th or 7th century BC. In the Iliad, the god Hephaestus made talking handmaidens out of gold. Archytas of Tarentum is created with creating a mechanical Pigeon in 400 BC. Robots are used in industrial, military, exploration, home making, and academic and research applications.

Manipulation

• Robots which must work in the real world require some way to manipulate objects; pick up, modify, destroy or otherwise have an effect. Thus the 'hands' of a robot are often referred to as end effectors while the arm is referred to as a manipulator. Most robot arms have replacable effectors, each allowing them to perform some small range of tasks. Some have a fixed manipulator which cannot be replaced, while a few have one very general purpose manipulator, for example a humanoid hand.

• * Grippers: A common effector is the gripper. In its simplest manifestation it consists of just two fingers which can open and close to pick up and let go of a range of small objects. See End effectors .

• * Vacuum Grippers: Pick and place robots for electronic components and for large objects like car windscreens, will often use very simple vacuum grippers. These are very simple astrictive devices, but can hold very large loads provided the prehension surface is smooth enough to ensure suction.

• * General purpose effectors: Some advanced robots are beginning to use fully humanoid hands, like the Shadow Hand (right), or the Schunk hand. These highly dexterous manipulators, with as many as 20 degrees of freedom and hundreds of tactile sensors can be difficult to control. The computer must consider a great deal of information, and decide on the best way to manipulate an object from many possibilities.

Human interaction

• If robots are to work effectively in homes and other non-industrial environments, the way they are instructed to perform their jobs, and especially how they will be told to stop will be of critical importance. The people who interact with them may have little or no training in robotics, and so any interface will need to be extremely intuitive. Science fiction authors also typically assume that robots will eventually communicate with humans by talking, gestures and facial expressions, rather than a command-line interface. Although speech would be the most natural way for the human to communicate, it is quite unnatural for the robot. It will be quite a while before robots interact as naturally as the fictional C3P0.

• * Speech Recognition: Interpreting the continuous flow of sounds coming from a human, in real time, is a difficult task for a computer, mostly because of the great variability of speech. The same word, spoken by the same person may sound different depending on local acoustics, volume, the previous word, whether or not the speaker has a cold, etc.. It becomes even harder when the speaker has a different accent. Nevertheless, great strides have been made in the field since Davis, Biddulph, and Balashek designed the first "voice input system" which recognized "ten digits spoken by a single user with 100% accuracy" in 1952. Currently, the best systems can recognise continuous, natural speech, up to 160 words per minute, with an accuracy of 95%.
  
• * Gestures: One can imagine, in the future, explaining to a robot chef how to make a pastry, or asking directions from a robot police officer. On both of these occasions, making hand gestures would aid the verbal descriptions. In the first case, the robot would be recognising gestures made by the human, and perhaps repeating them for confirmation. In the second case, the robot police officer would gesture to indicate "down the road, then turn right". It is quite likely that gestures will make up a part of the interaction between humans and robots. A great many systems have been developed to recognise human hand gestures.

• * Facial expression: Facial expressions can provide rapid feedback on the progress of a dialog between two humans, and soon it may be able to do the same for humans and robots. A robot should know how to approach a human, judging by their facial expression and body language. Whether the person is happy, frightened or crazy-looking affects the type of interaction expected of the robot. Likewise, a robot like Kismet can produce a range of facial expressions, allowing it to have meaningful social exchanges with humans.

• * Personality: Many of the robots of science fiction have personality, and that is something which may or may not be desirable in the commercial robots of the future. Nevertheless, researchers are trying to create robots which appear to have a personality: i.e. they use sounds, facial expressions and body language to try to convey an internal state, which may be joy, sadness or fear. One commercial example is Pleo, a toy robot dinosaur, which can exhibit several apparent emotions.

Control

• The mechanical structure of a robot must be controlled to perform tasks. The control of a robot involves three distinct phases - perception, processing and action (robotic paradigms). Sensors give information about the environment or the robot itself (e.g. the position of its joints or its end effector).
  
• Using strategies from the field of control theory, this information is processed to calculate the appropriate signals to the actuators (motors) which move the mechanical structure. The control of a robot involves path planning, pattern recognition, obstacle avoidance, etc. More complex and adaptable control strategies can be referred to as artificial intelligence.