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 second 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 muscles 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 example 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.

Kinematics and Dynamics

Kinematics is the branch of mechanical engineering that describes the motion of objects without considering the forces that cause motion. Dynamics is the study of the causes of motion and changes in motion. Both of these fields together help scientists improve their control algorithms for robots. Direct kinematics deals with the calculations for end effector positioning, orientation, velocity and acceleration when the corresponding joint values are known. Inverse kinematics deals with the exact opposite case. With inverse kinematics the joint values are calculated for given end effects values. This concept is used for the path planning of a robot. Once all of these measurements are calculated, methods from dynamics are used to study the effect of forces upon these movements. Direct dynamics deals with the calculation of accelerations in the robot once the applied forces are known. This type of dynamics is usually used for computer simulations of a robot. Inverse dynamics calculates the actuator forces needed in order to create an end effector acceleration. Combining the fields of kinematics and dynamics enables scientists and robot engineers to formulate and improve algorithms used for designing the motion of robots.

Classiﬁcation of Robots

There are three different types of classifications that we can use to distinguish robots, the JIRA classification, the RIA classification, and the AFRI classification.

6 The JIRA Classiﬁcation

CLASS 1: MANUAL HANDLING DEVICES A device with several degrees of freedom, which refers to the number of indepen- dent movements the object can make with respect to the coordinate system, actuated by the operator. CLASS 2: FIXED SEQUENCE ROBOT A handling device that performs the successive stages of a task according to a predetermined method, and therefore is diﬃcult to modify. CLASS 3: VARIABLE SEQUENCE ROBOT A handling device just as in Class 2, however these can be easily modiﬁed. CLASS 4: PLAYBACK ROBOT A robot that when performing its task is manually led by a human operator. The robot then records the routine, recalls it when necessary, and performs the task in automatic mode. CLASS 5: NUMERICAL CONTROL ROBOT A robot where a human operator programs the movement, instead of manually teaching it the task to accomplish. CLASS 6: INTELLIGENT ROBOTS A robot that has the capability to understand its environment as well as the changes in the environment, then accomplishes its tasks accordingly.

The RIA Classiﬁcation

This systems classiﬁes the machines from classes three to six of the JIRA classiﬁcation to be robots.

7 The AFRI Classiﬁcation

TYPE A: Represents the first class of the JIRA classification; refers to a handling device with manual control. TYPE B: Represents the second and third classes of the JIRA classification; refers to a automatic handling device that uses a predetermined cycle of routines. TYPE C: Represents the fourth and fifth classes of the JIRA classification; refers to a programmable robot, known as the first generation robots TYPE D: Represents the sixth class of the JIRA classification; refers to robots that can acquire information about the environment, known as second generation robots.

Future of Robots

Advances in robotics are geared towards robots being used in everyday life. Presently, the number of robotic related jobs have been increasing due to the fact that robotics is an important component in the modern manufacturing environment. However, the relationship between robotics and unemployment have a connection as well, although in this aspect it is a negative impact. Since the advancement of robots, many capable human operators have been replaced by robots. This replacement has caused unemployment to rise over the past years. Although many workers are out of work due to robots, there are many highly skilled engineers and scientists that work to further develop the robot. In 2007, the Ministry of Information and Communication of South Korea stated that every South Korean household will have a robot by the years 2015 to 2020. In addition, this year South Korea announced that they deployed a robot capable of killing intruders at their borders. The robot cost four hundred million won and was installed this past summer at a guard post in the central section of the De-

8 militarised Zone. The news agency Yonhap says, [?] the robot uses heat and motion detectors to sense possible threats, and then alerts command centers. If the command center operator cannot identify possible intruders through the robots audio or video communications system, the operator can order it to fire its gun or 40mm automatic grenade launcher. Also in the making, South Korea is attempting to develop highly sophisticated combat robots which are armed with weapons in order to complement human soldiers on the battlefield. Furthermore, the United States Department of Defense stated that by 2038, they will have completed the first autonomous robot flying car. Japan is also investing a majority of its money to building sophisticated robots. According to Japans National Institute of Science and Technology Policy (NISTEP), they are expected to have agricultural robots by 2014, robots that care for the elderly by 2017, and household robots by 2019. Furthermore, they expect to complete the first nanorobot by 2021. Nanorobots are very small robots, close to the microscopic scale of a nanometer. As the human race approaches a life with robots, the UK Office of Science and Innovation Horizon Scanning Centre states that robots may in fact one day demand for the same legal rights as human beings. Although, this may take decades to occur, we as the human race should prepare for all the perks and downfalls for a life coexisting with robots.

References

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9 [Coiﬀet, 1983] Coiﬀet, Philippe. An Introduction to Robot Technology. London: Her- mes Publishing, 1983.

[Cook, 2002] Cook, David. Robot Building for Beginners. New York City: Sringer- Verlag New York Inc., 2002.

[Kopp, 2010] Kopp, Emilie. ”The D.O.D Opens Up to Social Networking.” Ethics of Military Robots. N.p., 10 Feb. 2010. Web. 5 Nov. 2010. ¡http://labviewrobotics.wordpress.com/tag/dod/¿.

[MIT, 1999] MIT Leg Laboratory, prod. ”Running Robots.” Leg Laboratory. MIT, 1999. Web. 4 Nov. 2010. ¡http://www.ai.mit.edu/projects/leglab/copyright.html¿.

[Pike, 2010] Pike, John. ”Military Robots / Unmanned Ground Vehi- cles (UGV).” www.globalsecurity.org. N.p., 2010. Web. 5 Nov. 2010. ¡http://www.globalsecurity.org/military/systems/ground/ugv.htm¿.

[RIA, 2010] Robotics Institute of America. ”Robot Terms and Deﬁnitions.” Robotics Online. Robotics Industries Association, 19 Jan. 2010. Web. 6 Nov. 2010. ¡http://www.robotics.org/ product-catalog-detail.cfm?productid=2953¿.

[Telegraph, 2010] The Telegraph. ”South Korea deploys robot capable of killing intruders along border with North.” www.telegraph.co.uk. N.p., July 2010. Web. 9 Nov. 2010. ¡http://www.telegraph.co.uk/ news/worldnews/asia/southkorea/7887217/ South-Korea-deploys-robot- capable-of-killing-intruders-along-border-with-North.html¿.