Module 5: Robotics Technology
You have heard of the word “robots” during all your live; however you do not heard
about the word “robotics” to often. In this section we are going to cover the basis concepts of robotics. Let star with a definition of the word itself; Robotics is a science of
modern technology of general purpose of programmable machine systems. Contrary to the popular fiction image of robot as ambulatory machines of human appearance capable of performing almost any task. Most robotic systems are anchored to fixed positions in reality with limit mobility. Robots perform a flexible, but restricted, number of
operations in computer-aided manufacturing processes. These systems minimally contain a computer or a programmable device to control operations and effecters, devices that perform the desired work. The next paragraph represents the vision or general definition of robots according to the scientific knowledge and technology of that era. General definition for Robot
"A re-programmable, multifunctional mechanical manipulator designed to move material, parts, tools, or specialized devices through various programmed motions for the performance of a variety of tasks."
-- From the Robot Institute of America, 1979
This is the most important issue that educators, parents and students are being questioning for a while why is robotics important for my child?
The response is simple Robotics is a science that combines a range of fields like
Mechanical Engineering, Electrical Engineering, and Computer Science. Robotics is
ideal for adolescent students because it exposes them to hands-on applications of math, science, and engineering concepts. In addition, robotics motivates potential scientists and engineers to understand how things work and encourages them to use their imagination to create new technologies and improve old technologies. The next part of this extended background should cover the main components of a robot including some basic concepts for third to fifth grade.
Now a day thinks are getting sophisticated with more technological advance. A new perception and vision of the robot representation includes the following characteristics:
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； Mechanical platforms -- or hardware base is a mechanical device, such as a
wheeled platform, arm, fixed frame or other construction, capable of interacting with
its environment and any other mechanism involve with his capabilities and uses. ； Sensors systems is a special feature that rest on or around the robot. This device
would be able to provide judgment to the controller with relevant information about
the environment and give useful feedback to the robot. So it is able to perform his
； Joints provide more versatility to the robot itself and are not just a point that connects
two links or parts that can flex, rotate, revolve and translate. Joints play a very crucial
role in the ability of the robot to move in different directions providing more degree
； The Controller process sensory input in the context of the device's current situation
commanding the robot position and orientation of the tool or any part correctly in
space at all times. In other words, it is a computer used to command the robot
memory and logic. So it, be able to work independently and automatically. The
controller functions as the "brain" of the robot. Robots today have controllers that are
run by programs - sets of instructions written in code.
； Power Source is the main source of energy to fulfill all the robots needs. It could be a
source of direct current as a battery, or alternate current from a power plant, solar
energy, hydraulics or gas.
； Artificial intelligence represents the ability of computers to "think" in ways similar
to human beings. Examples might be reasoning, adaptation, decision making, and
learning from mistakes. At present, artificial intelligence has a long way to go before
machines can be considered truly "smart." Present day "AI" does allow machines to
mimic certain simple human thought processes, but can not begin to match the
quickness and complexity of the brain. On the other hand, not all robots possess this
type of capability. It requires a lot of programming and sophisticates controllers and
sensorial ability of the robot to reach this level.
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Like I wrote before, one of the most interesting aspects of robots in general is their behavior, which requires a form of intelligence. The simplest behavior of a robot is locomotion. Typically, joints and wheels are used as the underlying mechanism to make a robot move from one point to the next.
This type of motion should include the adaptability and versatility of the robot to
continue with a specific task. Adaptability means adjustment to the task being carried
out. In other words, the robot should be able to complete its process no matter what interferences might occur in the workplace. Versatility means that the robot should have
such a mechanical structure that it can carry out different tasks or perhaps the same task in different ways. This means that an installed robot should be able to be used when the production is changing, i.e. if the production is changing through the changes of the original product or the product is being exchanged.
The word "robot" has its origin from the German word "robat". This word survived in the Polish and Czeckish languages as "robota" and means compulsory labor. It appears that the science fiction writer Isaac Asimov was the first to use the word "robotics" to describe robot technology.
The first robots
Joseph Engel Berger, in the picture, is entitled to be the father of robotics, together with George Deroe developed the first commercial
robot, Unimate, in 1961. It was placed on Ford and was there used
for a press-loading operation. A picture of the first generation robots from Unimate can be seen in the picture below.
Joseph Engel Berger
The first robots were principally intended to replacing humans in
monotonous, heavy and hazardous processes. Distinctive
features of the use of the newly developed robots were in
handling of materials and work pieces without direct control or
participation in the manufacturing process. Robots did not
become a major force in industry generally until they had been
used extensively in the Japanese automobile industry. Unimate
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Major applications of industrial robots for (1997)
Other (Inspection,Procesing,Material Transfer,Machine Tending,and Food31.2industry, etc)8Spray painting/Coating
33Assembly (Automotive parts, Electronics,etc.)
12345 Spot or Arch Welding25
Fig. 1 Shows the percentage of applications of robots at the industry during 1997
In the above paragraph the authors put into the picture the word mechanical
manipulator but what this physically means? Mechanical manipulator is a device that
consists of a base frame, rigid or flexible links, and joints, tool frame attached to the end effector or gripper. The following figure provides a better perception of a Mechanical
Fig.2 Mechanical Manipulator parts and reference frames
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Physical Robot configurations
Over the years robot manufacturers have developed many types of robots of
differing configurations and mechanical design, to give a variety of spatial arrangements
and working volumes. These have evolved into six common types of system: Cartesian,
Cylindrical, Spherical, SCARA (Selective Compliance Assembly Robot Arm),
Articulated arm, and Parallel Robots.
“Workspace envelope” is one of the new terms that are going to be covered in
the following table. It really describes how the robot is constrained by its mechanical
systems configuration. Each joint of a robot has a limit of motion range. By combining
all the limits, a constrained space can be defined. A workspace envelope of a robot is
defined as all the points in the surrounding space that can be reached by the robot. The
area reachable by the end effector itself is usually not considered part of a work envelope.
Clear under standing of the workspace envelope of a robot to be used is important
because all interaction with other machines, parts, and processes only takes place within
this volume of space.
Model Workspace Envelope Physical Configurations
Cartesian robot it is form by 3 prismatic joints,
whose axes are coincident with the X, Y and Z
planes. These robots move in three directions, in
translation, at right angles to each other.
Cylindrical robot is able to rotate along his main
axes forming a cylindrical shape.
The robot arm is attached to the slide so that it can
be moved radially with respect to the column.
Spherical robot is able to rotate in two different
directions along his main axes and the third joint
moves in translation forming a hemisphere or polar
It used for a small number of vertical actions and is
adequate for loading and unloading of a punch ;;
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SCARA robot which stands for Selective
Compliance Assembly Robot Arm it is built with 2
parallel rotary joints to provide compliance in a
plane. The robots work in the XY-plane and have
Z-movement and a rotation of the gripper for assembly. ;;;
Articulated robots are mechanic manipulator
that looks like an arm with at least three rotary
joints. They are used in welding and painting;
gantry and conveyor systems move parts in
Parallel robot is a complex mechanism which is
constituted by two or more kinematics chains
between, the base and the platform where the end-
effector is located. Good examples are the flying
simulator and 4-D attractions at Univ. Studios
Types of robots according his application
Various robots are quite simple mechanical machines that perform a dedicated
task such as spot welding orassembly operations a repetitive nature task. Besides more
complex, multi-task robots systems use sensory systems to gather information needed to
control its movement. These sensors provide tactile feedback to the robot so it is able to
pick up objects and place them properly, without damaging them. A further robot sensory
system might include machine visualization to detect flaws in manufactured supplies.
Few robots used to assemble electronic circuit boards can place odd-sized components in
the proper location after visually locating positioning marks on the board.
Simple mobile robots are used to deliver mail or to gather and deliver parts in
manufacturing. They are program to follow the path of a buried cable or a painted line,
stopping whenever their sensors detect an object or person in their path. Other complex
mobile robots are used in more unstructured environments such as mining.
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Types of robots according his application Picture
Industrial Robots are found in a variety of locations including the automobile and manufacturing industries. However, robot technology is relatively new to the industrial scene their roll consists of welding, painting, material handling and assembling.
Educational Robots one example is the Hex Avoider.
It is a programmable mobile robot designed to move
independently and avoid obstacles. Hex avoider use infrared emitters and receivers to sense its environment. Their roll is demonstrational for teaching basic concepts and gets the attention of future engineers to this field.
Mobile Robots (Transportation) these types of robot operate by
control remote deploying sensor position. Their roll consist of sampling payloads, mapping surface and creating a photorealistic 3D models and sent back any kind of visual information of building interiors and any environmental data.
Robots in Space are name as Remotely Operated Vehicle (ROV). It can be consistent with an unmanned spacecraft that remains in flight or 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.
Agricultural Robots one example is the Demeter harvester it
contains new controllers, proximity sensors, safeguards and task software specialized to the needs of commercial agriculture processes.
Health Care Robots they are able to perform simple task and
improve some medical protocol and procedures. An example is the daVinci’ Robotic Surgical System. It is a manipulator guided by surgeon’s hands placed in the robotic console, it increased the precision movements, provides top-quality clinical outcomes and is cosmetically superior to open surgery, decrease blood loss and postoperative complications; and decrease the length of hospital stay.
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Degrees of freedom
A degree of freedom is also a term that was cover on page number two and it can be defined as the direction in which a robot moves when a joint is actuated. Each joint usually represent one degree of freedom. Most of the robots used today use five or six degrees of freedom. But this depends on the robot application, for example a pick-and-place application need only three axes specified when a welding robot requires five or six degrees of freedom. Six degrees of freedom are necessary to emulate the motion of a human arm and wrist.
Types of joint links of a manipulator mechanism Diagram
Rotary or revolute joints, these are the most utilized
joint and it rotates along the pin as an axis.
Prismatic or Sliding joints, these are the second most
employed joint and just slide causing a translation
Spherical joints, these are the third most utilized joint
and just slide causing a revolving movement.
Screw joints, these just follow the thread of the axis in
spiral to move along the axis.
Cylindrical joints, these are very rare and are use in
some equipment like Parallel Robots or Flying simulator
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The word sensor comes from the word sense and it is originate from the Middle
French sens, sensation, feeling, and mechanism of perception. It consists of a mental process (as seeing, hearing, or smelling) due to immediate bodily stimulation often as distinguished from awareness of the process. In other words is the way that humans or living things recognize their environment or surroundings. To improve the performance of the robots it must be able to sense in both ways their internal and external states (the environment) to perform some of the tasks presently done by humans. A sensor can be described as a measurement device that can detect characteristics through some form of interaction with these characteristics. Currently several sensors are applied to robots on factory floors, and this fact increases the flexibility, accuracy, and repeatability of robots. Also, much more accurate and intelligent robots are expected to emerge with the newly developed sensors, especially visual sensors.
Vision provides a robot with a sophisticated sensing mechanism that allows the machine to respond to its environment in an intelligent and flexible manner. I think that you really wonder how this information is gathered by robots. First of all, this sensorial perceptions or measurements are gathered by electronic signals, or data that sensors could provide with a limited feedback to the robot so it can do its job. Most robots of today are nearly deaf and blind, compared to the senses and abilities of even the simplest living things. Although proximity, touch, and force sensing play a significant role in the improvement of robot performance. However, vision is recognized as the most
powerful robot sensory capability.
Robot vision may be defined as the process of extracting, characterizing, and interpreting information from images of a three-dimensional world. This process, also commonly referred to as computer or machine vision, may be subdivided into six principal areas: sensing, preprocessing, segmentation, description, recognition, and interpretation. It is convenient to group these various areas according to the sophistication involved in their implementation. The major drawback is the accuracy of this images and interpretations. It is required to combine this potential with tactile sensors to provide a better insight of the contact part more accurately than that provided just with the robot vision.
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Sensors can be classified in different ways. In the following, some typical robotics sensors are introduced.
Description of Different Type of Sensors
A proximity sensor senses and indicates the presence of an object within a fixed space near the sensor without physical contact. Different commercially available proximity sensors are suitable for different applications. A common robotics proximity sensor consists of a light-emitting-diode (LED) transmitter and a photodiode receiver. The major drawback of this sensor stems from the dependency of the received signal on the orientation and reflectance of the intruding object. This drawback can be overcome by replacing proximity sensors with range sensors.
Optical proximity sensors Magnetic proximity sensors
A range sensor measures the distance from a reference point to a set of points in the
scene. Humans can estimate range values based on visual data by perceptual processes that include comparison of image sizes and projected views of world-object models. Basic optical range-sensing schemes are classified according to the method of illumination (passive or active) and the method of range computation. Range can be sensed with a pair of TV cameras or sonar transmitters and receivers. Range sensing based on triangulation has the drawback of missing data of points not seen from both
positions of the transmitters. This problem can be reduced, but not eliminated, by using additional cameras.
The AR200 line is the most compact series of
triangulating laser displacement sensors. Four
modules cover metric measurement ranges Range Sensor from 6 to 50 millimeters.
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