Robotics Paper Anita Khachikian November 9, 2010 History and Introduction to Robotics The field of Robotics, though it has been around for decades, is constantly developing with new technological advances. The more advanced robots get, the harder it is to imagine robots existing in the past. However, there have been stories of artificial helpers and comrades since the 1920's. The term 'robot' was first introduced in 1921 by the Czech writer Karel Capek in his play Rossum's Universal Robots. Capek came up with the word robot from the Czech word "robota" which means forced labor. Then in 1927, the film Metropolis depicted, for the first time ever on film, a gynoid humanoid robot which is basically a robot with the overall appearance of a woman. The conceptualization of robots developed even further in 1942 when the American author and professor of biochemis ry Isaac Asimov concocted the Three Laws of Robotics. The first law states that a robot may not injure a human being or, through inaction, allow a human being to come to harm. The second law states that a robot must obey any orders given to it by human beings, except where such orders would conflict with the first law. Finally, the third law states that a robot must protect its own existence as long as such protection does not conflict with the first or second laws. Although these laws were formulated for fictional robots that had sensibility and consciousness, they serve as building blocks for robotic engineers in the present. 1 The general the term robotics involves the development of robots as well as the processes that are associated with them. Robotic systems is an idea generated from the evolution of automation systems. According to Wikipedia, [?] automation is the use of control systems and information technologies to reduce the need for human work in the production of goods and services. An example of a fairly new automation system is the telephone switchboards and operating machines that have taken the place of human telephone operators. Robotics developed because automation systems lacked sophisticated devices, which as a result disallowed the machine to adapt to its environment. For example, various tasks which are performed by human operators are repetitive, however not every detail may be the same. Therefore a robot must be able to recognize any changes to the environment and must act accordingly in order to replace a human operator. This led to the development of the interactive robot which can recognize and react to changes in its surroundings. The basic characteristics that separate robotic systems from existing automated machines are that robotic systems are flexible and versatile. The versatility refers to the structural and mechanical components which allow performing varied tasks. The study of variable geometry allows us to obtain the mechanical structure of the robot. The flexibility refers to the capability of robots adapting to their environments. This enables the robot to perform the tasks given despite unforeseen changes in the environment. This leads us to the definition of a robot given by the Robot Institute of America which reads, [?] a robot is a reprogrammable and multifunctional manipulator, devised for the transport of materials, parts, tools, or specialized systems, with varied and programmed monuments, with the aim of carrying out varied tasks. 2 The Structure of a Robot The general structure of a robot is consisted of five interactive elements. The first is the Articulate Mechanical System, referred to as AMS, which refers to the actual limbs of the robot. For this area, we use a geometrical structure of the robot system in order to make a functional representation. Most robots in the world are used for some sort of work that requires hands in order to complete the work. These hands are called the end effectors. Advanced robots tend to use General Purpose Effectors, which have up to twenty degrees of freedom and hundreds of tactile sensors. The sec- ond element of a robot is its actuators, which provide power that comes in the forms of electrical, hydraulic or pneumatic.The actuators can be thought of as the mus- cles of the robot. One example of an actuator is the Pneumatic Artificial Muscles, which are special tubes that contract when air is forced inside it. Another exam- ple is Electroactive Polymers which consists of new plastic material that contracts from electricity. This actuator has been used in order to carry out facial and arms movements for humanoid robots. The third is the transmission device which link the actuators and the Articulate Mechanical System together. This generates movements in the individual parts of the mechanical system. Examples of these devices include cables, bands, gears, etc,. The fourth element is the sensors which may be in the form of tactile, electrical, optical and others alike. They are used to obtain information on the position of the articulations and on objects in the robots surroundings. It follows then that the configuration of the AMS determines the form of the robot. Recently, a tactile sensor array has been developed for the sense of touch for robots. Furthermore, in 2009, scientists from several European countries developed a prosthetic hand called SmartHand, which behaves just like the human hand. The SmartHand is composed of sensors which enables the user to sense real feelings in its fingertips. Another compo- 3 nent of the senses a robot may attain is vision. There is a subfield of Computer Vision that is used in order to accomplish the task of sight for a robot, which is designed to mimic the process of our own biological system. The final fifth element of a robot is the computer unit that acts as the "brain" of the machine. The computer processes data received by the robot through its sensors. Stored in the computers memory are models that define the relationship between the actuators and the movements that follow, and models that give a description of the robots environment. Also included in the memory are programs which allow the computer to understand the tasks to be performed and which provide control of the robots structure in order for the robot to carry out its tasks. These computer instructions are known as control algorithms. While the robot is accomplishing its task, the computer assesses the state of the robot as well as the environment by using internal and external sensors respectively. It then uses the models and programs stored in the memory to generate commands which enables the robot to proceed with the completion of its task. Locomotion Different Types of Locomotion for Robots There are a variety of ways a robot can move, and hence robots may be classified by their locomotion. One type of motion is by the use of wheels. This includes 2- wheeled, 4-wheeled and 6-wheeled robots, as well as tracked robots which operate as if they were made with a hundred wheels. Tracked robots provide more traction than 6-wheeled robots and therefore is mostly used on rough terrain. Another type of locomotive robots are walking robots. There have been many robots that have been invented that can walk on flat ground with two legs, however none are built 4 as well as the human body. Many methods have been introduced in order to fix this problem. One such method is known as the Zero Moment Point Technique which is an algorithm that is programmed into the robot. The algorithm enables the robots computer to record all inertial forces, which consist of the Earths gravity and the robots acceleration and deceleration of walking, and the opposed reaction force, which is the force of the floor pushing back on the robots foot. These opposing forces cancel out, hence leaving no force which may cause the robot to rotate and fall over. Although this technique works, the way the robot walks is in a stiffer manner than of a human beings walk. Another method developed was in the 1980´ s by Marc Raibert at the MIT Leg Laboratory. His technique allowed a robot with only one leg to move around by hopping. Later on, his technique was used in order to generalize an algorithm for two-legged walking. One such robot invented by the scientists of the MIT Leg Laboratory was called the 3D Biped which was devised through the years 1989 to 1995. This robot, although does not have a physical resemblance to a human, is able to hop, run, and perform tucked somersaults. Also, another machine was invented through the years 1985 to 1990 and was called the Planar Biped. This robot was used to test the fact that Raiberts one-legged control algorithm could in fact be generalized for two-legged running. Basically the robot uses its control system to designate an active leg and an idle leg. It follows that since only one leg is active at a time, the one-legged algorithm is applied to control the bipeds behavior. By using this method, the biped runs with a hopping gait, and can also change gaits while running. This biped helped scientists study the general locomotion on rough terrains and the locomotion for running at a high speed. Another way type of motion for robots is called snaking. The robots that use this type of motion also look like real snakes because the way they move mimics real snakes. These robots can maneuver in confined spaces, and hence are built to one day be used to search for people in 5 collapsed buildings. There also have been many other robots invented with different locomotive motions, for example there are robots that can skate, climb, or swim.