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Flashcards in Robotics Deck (19)
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When was the word robot first used?

The word robot was introduced to the public by
the Czech writer Karel Čapek in his play R.U.R. (Rossum's Universal Robots), published in 1920. The play begins in a factory that makes artificial people called robots creatures who can be mistaken for humans – though they are closer to the modern ideas of androids. Karel Čapek himself did not coin the word. He wrote a short letter in reference to
an etymology in the Oxford English Dictionary in which he named his brother Josef Čapekas its actual originator.


What was the first depiction of a robot on film?

In 1927 the Maschinenmensch ("machine- human") gynoid humanoid robot (also called "Parody", "Futura", "Robotrix", or the "Maria impersonator") was the first and perhaps the most memorable depiction of a robot ever to appear on film was played by German actress Brigitte
Helm in Fritz Lang's film Metropolis.


Who coined the word robotics?

In 1942 the science fiction writer Isaac Asimov formulated his Three Laws of Robotics and, in the process of doing so, coined the word "robotics".


When were the first robots used and what for?

Fully autonomous robots only appeared in the second half of the 20th century. The first digitally operated and programmable robot, the Unimate, was installed in 1961 to lift hot pieces of metal from a die casting machine and stack them.


How are robots used today?

Commercial and industrial robots are widespread today and used to perform jobs more cheaply, or more accurately and reliably, than humans. They are also employed in jobs which are too dirty, dangerous, or dull to be suitable for humans. Robots are widely used in manufacturing, assembly, packing and packaging, transport, earth and space exploration, surgery, weaponry, laboratory research, safety, and the mass production of consumer and industrial goods.


Definition of robotics

The word robotics was derived from the word robot, which was introduced to the public by Czech writer Karel Čapek in his play R.U.R. (Rossum's Universal Robots), which premiered in 1921. The word robotcomes from the Slavic word robota, which is used to refer forced labor.


First use of the word robotics?

According to the Oxford English Dictionary, the word robotics was first used in print by Isaac Asimov, in his science fiction short story "Liar!", published in May 1941 in Astounding Science Fiction. Asimov was unaware that he was coining the term; since the science and technology of electrical devices
is electronics, he assumed robotics already referred to the science and technology of robots. In some of Asimov's other works, he states that the first use of the word robotics was in his short
story Runaround (Astounding Science Fiction, March 1942). However, the original publication of "Liar!" predates that of "Runaround" by five months, so the former is generally cited as the word's origin.


Structure of robots

The structure of a robot is usually mostly mechanical and can be called a kinematic chain (its functionality being similar 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 a closed parallel kinematical chain. 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.


Robot power sources

At present mostly (lead-acid) batteries are used as a power source. Many different types of batteries can be used as a power source for robots. They range from lead acid batteries which are safe and have relatively long shelf lives but are rather heavy to silver cadmium batteries that are much smaller in volume and are currently much more expensive. Designing a battery powered robot needs to take into account factors such as safety, cycle lifetime and weight. Generators, often some type of internal combustion engine, can also be used. However, such designs are often mechanically complex and need fuel, require heat dissipation and are relatively heavy. A tether connecting the robot to a power supply would remove the power supply from the robot entirely. This has the advantage of saving weight and space by moving all power generation and storage components elsewhere. However, this design does come with the drawback of constantly having a cable connected to the robot, which can be difficult to manage. Potential power sources could be:
• pneumatic (compressed gases)
• hydraulics (liquids)
• flywheel energy storage
 organic garbage (through anaerobic digestion)


What are robotic actuators?

Actuators are like the "muscles" of a robot, the parts which convert stored energy into movement. By far the most popular actuators are electric motors that spin a wheel or gear, and linear actuators that control industrial robots in factories. But there are some recent advances in alternative types of actuators, powered by electricity, chemicals, or compressed air.


What motors do robots use?

The vast majority of robots use electric motors, often brushed and brushless DC motors in portable robots or AC motors in industrial robots and CNC machines. These motors are often preferred in systems with lighter loads, and where the predominant form of motion is rotational.


What are stepper motors?

As the name suggests, stepper motors do not spin freely like DC motors; they rotate in discrete steps, under the command of a controller. This makes them easier to control, as the controller knows exactly how far they have rotated, without having to use a sensor. Therefore, they are used on many robots and CNC machines.


What are piezo motors?

A recent alternative to DC motors are piezo motors
or ultrasonic motors. These work on a fundamentally different principle, whereby tiny piezoceramic elements, vibrating
many thousands of times per second, cause linear or rotary motion. There are different mechanisms of operation; one type uses the vibration of the piezo elements to walk the motor in a circle or a straight line. Another type uses the piezo elements to cause a nut to vibrate and drive a screw. The advantages of these motors are nanometer resolution, speed, and available force for their size. These motors are already available commercially, and being used on some robots.


What are air muscles?

The air muscle is a simple yet powerful device for providing a pulling force. When inflated with compressed air, it contracts by up to 40% of its original length. The key to its behavior is the braiding visible around the outside, which forces the muscle to be either long and thin, or short and fat. Since it behaves in a very similar way to a biological muscle, it can be used to construct robots with a similar muscle/skeleton system to an animal. For example, the Shadow robot hand uses 40 air muscles to power its 24 joints.


What are electroactive polymers?

Electroactive polymers are a class of plastics which change shape in response to electrical stimulation. They can be designed so that they bend, stretch, or contract, but so far there are no EAPs suitable for commercial robots, as they tend to have low efficiency or are not robust. Indeed, all of the entrants in a recent competition to build EAP powered arm wrestling robots, were beaten by a 17 year old girl. However, they are expected to improve in the future, where they may be useful for microrobotic applications


What are elastic nanotubes?

These are a promising, early-stage experimental technology. The absence of defects in nanotubes enables these filaments to deform elastically by several percent, with energy storage levels of perhaps 10J per cu cm for metal nanotubes. Human biceps could be replaced with an 8mm diameter wire of this material. Such compact "muscle" might allow future robots to outrun and out jump humans


What is the importance of manipulation to robots?

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 replaceable 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.


What is a good effector (hand) for robots?

One of the most common effectors 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.


What are 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