Industrial robots have six basic components: a manipulator, end effector, actuators, sensors, controller, and teach pendant. The manipulator consists of links and joints that give the robot its degrees of freedom. Actuators like electric motors provide movement. Sensors provide feedback and safety. The controller coordinates movement based on taught positions. Programming modes include teach, walk, and software modes. Key robot characteristics are payload, reach, precision, and repeatability. Safety systems use sensors to detect intrusions and stop robots to prevent harm.

1. CHAPTER 2
INDUSTRIAL ROBOT TECHNOLOGY
by
NORHAFIZA BT SAMION
PPD, UTHM
DEK 3223 Automation System and Robotics

2. Life Motivation
Sabda Nabi Muhammad SAW:
“Barangsiapa mencintai dunia, urusan akhiratnya akan
tercicir. Dan barang siapa yang mencintai akhirat, dunia
akan mengikutnya. Dan pilihlah yang kekal daripada yang
cepat binasa.”
(HR Bukhari dan Muslim)

3. **Bertafakur bagi yang bukan muslim

4. Topics
• Introduction
• Basic Components
▫ Manipulator
▫ End Effector
▫ Actuators
▫ Sensors
▫ Controller
▫ Teach Pendant
• Robot Reference Frames
• Robot Workspaces
• Programming Modes
• Robot Characteristics
• Robot Safety

5. Introduction
• Definition by Robotics Industries Association:
“Industrial robot is an automatically controlled, reprogrammable,
multipurpose manipulator programmable in three or more axes, which may
be fixed in either place or mobile for use in industrial automation
applications”
• The first industrial robot was manufactured by Unimate and installed by
General Motors in 1961.
• Most applications of industrial robot are in welding, painting, and pick and
place operations.
• Welding and painting robots are very common used in automotive
industry, which need accuracy, high-speed operation, and human safety.
• Pick and place operations need a robot to pick up parts and place them
elsewhere. This may include palletizing, placing, sorting and assembly
parts or other similar routines.

6. Basic Components
• Robot system is combination of multidiscipline area, which includes
implementation of mechanics, electrical and electronic systems, software
engineering, and numerous other fields of application interest.
• Most of the industrial robots have six basic components: manipulator, end
effector, actuators, sensors, controller, and teach pendant.

7. Basic Components..

8. Manipulator
• Manipulator is a main body for the robot and consists of the joints, links
and other structural elements of the robot.
• It is a collection of mechanical linkages (or link) connected by joints and
included are gears, coupling devices, and so on.
• Generally, joints of a manipulator fall into two classes:
▫ revolute (rotary)
▫ prismatic (linear).
• Each of the joints of a robot defines a joint axis along which the
particular link either rotates or slides (translates).
• Every joint axis identifies a degree of freedom (DOF).
► No. of DOFs = No. of Joints.

9. Manipulator..
• Regardless of its mechanical configuration, the
manipulator defined by the joint-link structure
generally contains three main structural elements
as human parts:
▫ the arm
▫ the wrist
▫ the end effector.
 Most robots are mounted on stationary base on the floor and its
connection to the first joint as called link 0. The output link of
joint 1 is link 1, and so on.

10. Manipulator...
• Besides the mechanical components, most manipulators also contain
the devices for producing the movement of the various mechanical
members.
• These devices are referred to as actuators and may be pneumatic,
hydraulic, or electrical in nature.
• They are either directly or indirectly, coupled to the various mechanical
links or joints (axes) of the arm.
• In the latter case, gears, belts, chains, harmonic drives, or lead screws
can be used.
• The interface between the last link and the end effector is called the
tool mounting plate or tool flange.

11. End Effector
• End effector is the part that is connected to the last joint (hand) of a
manipulator, which generally handles objects, makes connection to other
machines, or performs the required tasks.
• Robot manufacturers generally do not design or sell end effectors; just
supply a simple gripper.
• This is the job of a company's engineers or outside consultants to design
and install the end effector on the robot and to make it work for the given
situation/task.
• In most cases, either the action of the end effector is controlled by the
robot's controller, or the controller communicates with the end effector's
controlling device such as a PLC.

12. End Effector..
• The end effectors can include a sensor to determine if a part is present.
• The addition of a simple sensor can make a gripper a relatively intelligent
device.
• For example
▫ A simple gripper that has a sensor in it which tells if there is something
between its jaws
▫ This could be as simple as a light and phototransistor
▫ If the robot is commanded to go and get a part, the manipulator will position
the tool to the correct location and then check the gripper’s sensor before
closing the gripper.

13. Actuators
• Actuators are used to move elements of the manipulators.
• It must have enough power to accelerate and decelerate the links and to
carry the loads, yet be light, economical, accurate, responsive, reliable, and
easy to maintain.
• Each actuator is driven by a controller.
• Common types of actuators are electric motors (servomotors and stepper
motors), pneumatic cylinders, and hydraulic cylinders.
• Electric motor especially servomotors are the most commonly used.
• Hydraulic systems were very popular for large robots in the past and still
around in many places, but are not used in new robots as often any more.
• Pneumatic cylinders are used in robots that have on-off type joints, as well
as for insertion purposes.

14. Electric Motor
Advantage Disadvantage
1. Good for all sizes of robots
2. Better control, good for high
precision robots
3. Higher compliance than hydraulics
4. Reduction gears used to reduce
inertia on the motor
5. Does not leak, good for clean
room
6. Reliable, low maintenance
7. Can be spark free, good for
explosive environments
1. Low stiffness
2. Needs reduction gears,
increased backlash, cost
and weight
3. Motor needs braking device
when not powered.
Otherwise, the arm will fall.

15. Pneumatic
Advantage Disadvantage
1. Many components are usually off-
the-shelf.
2. Reliable components.
3. No leaks or sparks.
4. Inexpensive and simple.
5. Low pressure compared to
hydraulics.
6. Good for on-off applications and
for pick and place.
7. Compliant systems.
1. Noisy systems.
2. Require air pressure, filter,
etc.
3. Difficult to control their
linear position.
4. Deform under load
constantly.
5. Very low stiffness and
inaccuracy response.
6. Lowest power to weight
ratio.

16. Hydraulic
Advantage Disadvantage
1. Good for large robots and
heavy payload.
2. Highest power/weight ratio.
3. Stiff system, high
accuracy, better response.
4. No reduction gear needed.
5. Can work in wide range of
speeds without difficulty.
6. Can be left in position
without any damage.
1. May leak and not fit for clean room
applications.
2. Requires pump, reservoir, motor, hoses, etc.
3. Can be expensive, noisy and requires
maintenance.
4. Viscosity of oil changes with temperature.
5. Very susceptible to dirt and other foreign
material in oil.
6. Low compliance.
7. High torque, high pressure, large inertia on
the actuator.

17. Sensors
• Adding sensors to an industrial robot can increase the range of tasks the
robot can perform.
• It also decreases the mechanical tolerances required of both the robot and
the robot’s environment.
• Sensors can be divided into three categories:
▫ internal sensors: tell a robot the position of its various joints and report other
conditions such as fluid pressure and temperature.
▫ external sensors: tell the robot what is happening outside.
▫ interlocks: used to protect both humans and robots. They may possess
features of both internal and external sensors.

18. Sensors..
• If robots are to use sensors in the middle of the electrical noise of a factory,
care must be used in transmitting information from them to the robot’s
controller without interference.
• If the sensor information is being shared with a production computer, the
possibility of noise problems is increased.
• Fiber optics or differential drivers may be needed to get the signals to the
controller.
• Many sensor devices give an analog signal, while the controller uses digital
signals; therefore analog-to-digital and digital-to-analog converter circuits may
be required.

19. Controller
• The controller receives its data from the computer, controls the motions of
the actuators, and coordinates the motions with the sensory feedback
information.
• Suppose that in order for the robot to pick up a part from a bin, it is
necessary that its first joint be at 35°.
• If the joint is not already at this magnitude, the controller will send a signal to
the actuator (a current to an electric motor, air to a pneumatic cylinder, or a
signal to a hydraulic servo valve), causing it to move.
• It will then measure the change in the joint angle through the feedback
sensor attached to the joint (a potentiometer, an encoder, etc.).
• When the joint reaches the desired value, the signal is stopped.

20. Teach Pendant
• The robot will move to various locations in performing its tasks.
• These locations can be determined by a controller system whenever the
robot’s working environment is defined.
• However, these locations are usually taught to the robot controller and used
by the operator to move the robot to desire locations.
• Teach pendants sometimes can also be used to issue other commands to
the robot or to teach a relatively simple program.

22. Quiz 1 (10 min)
• Label Link & joint of figure below and
determine how many DOF?

23. Each of these joints have a range over which it can be moved.
The five joint types illustrated in the figure are:

25. Life Motivation
Firman Allah SWT:
“Barangsiapa yang bertakwa kepada Allah, akan diberi jalan
keluar dari kesusahan, dan Allah akan memberi rezeki
yang tidak disangka-sangka datangnya.”
(At-Thalaq: 2-3)

26. Robot Reference Frames
• Robots may be moved relative to different coordinate frames.
There are 3 reference frame: world, joint, and tool.

27. Robot Workspaces
• Workspace or work envelope is an area which robot can reach.
• The shape of the workspace for each robot is uniquely related to its
characteristics of robot configuration, links and wrist joints.
• The workspace may be found mathematically by writing equations that
define the robot's links and joints and including their limitations, such as
ranges of motions for each joint.
• When a robot is being considered for a particular application, its
workspace must be studied to ensure that the robot will be able to reach
the desired points.

28. Typical Workspaces for
Common Robot Configurations

29. Typical Workspaces for
Cartesian Configuration

30. Typical Workspaces for
Cylindrical Configuration

31. Typical Workspaces for
Polar Configuration

32. Typical Workspaces for
Jointed-Arm Configuration

33. Typical Workspaces for SCARA
(Selective Compliance Assembly Robot Arm)

44. Programming Modes
• Robots may be programmed in a number of different modes, depending
on the complexity of robot function.
• 4 common programming modes:
▫ Physical Setup Mode
▫ Teach Mode
▫ Continuous Walk Mode
▫ Software Mode
• Most industrial robots can be programmed in more than one mode.

45. Programming Modes
• Physical Setup Mode
▫ In this mode, an operator sets up switches and hard stop that control the
motion of the robot.
▫ This mode is usually used along with other devices, such as
Programmable Logic Controllers (PLC).
• Teach Mode
▫ In this mode, the robot's joints are moved with a teach pendant.
▫ When the desired location and orientation is achieved, the location is
entered (taught) into the controller.
▫ During playback, the controller will move the joints to the same locations
and orientations.
▫ This mode is usually point to point, where the motion between points is not
specified or controlled.
▫ Only the points that are taught are guaranteed to reach.

46. Programming Modes
• Continuous Walk Mode
▫ In this mode, all robot joints are moved simultaneously, while the motion is
continuously sampled and recorded by the controller.
▫ During playback, the exact motion that was recorded is executed.
▫ The motions are taught by an operator, through a model, either by
physically moving the end effector, or by directing the robot arm and
moving it through its workspace.
• Software Mode
▫ In this mode of programming the robot, a program is written off-line or on-
line and is executed by the controller to control the motions.
▫ The programming mode is the most sophisticated and versatile mode and
can include sensory information, conditional statements (such as if...then
statements), and branching.
▫ However, it requires the knowledge of the operating system of the robot
before any program is written.

47. Robot Characteristics
• The following characteristics are typically used to describe commercial
industrial robots:
▫ Payload
▫ Reach
▫ Precision (validity)
▫ Repeatability (variability)

48. Robot Characteristics
• Payload
▫ Payload is the weight a robot can carry and remain within its specifications.
▫ If load capacity larger than its specified payload, it may become less
accurate, may not follow its intended path accurately, or may have excessive
deflections.
▫ The payload of robots compared with their own weight is usually very small.
>> Fanuc Robotics LR Mate™ robot has a mechanical weight of 86 lbs
and a payload of 6.6 lbs.

49. Robot Characteristics
• Reach
▫ Reach is the maximum distance a robot can reach within its work envelope.
▫ Many points within the work envelope of the robot may be reached with any
desired orientation (called dexterous).
▫ However, for other points, close to the limit of robot's reach capability,
orientation cannot be specified as desired (called non-dexterous point).
▫ Reach is a function of the robot's joint lengths and its configuration.

50. Robot Characteristics
• Precision (validity)
▫ Precision is defined as how accurately a specified point can be reached.
▫ This is a function of the resolution of the actuators, as well as its feedback
devices.
▫ Most industrial robots can have precision of 0.001 inch or better.

51. Robot Characteristics
• Repeatability (variability)
▫ Repeatability is how accurately the same position can be reached if the motion is
repeated many times.
▫ Suppose that a robot is driven to the same point 100 times. Since many factors
may affect the accuracy of the position, the robot may not reach the same point
every time, but will be within a certain radius from the desired point.
▫ The radius of a circle that is formed by this repeated motion is called repeatability.
Most industrial robots have repeatability in the 0.001 inch range.
▫ Repeatability is more important than precision. If a robot is not precise, it will
generally show a consistent error, which can be predicted and thus corrected
through programming.
▫ As an example, suppose that a robot is consistently of 0.05 inch to the right. In
that case, all desired points can be specified at 0.05 inch to the left, and thus the
error can be eliminated. However, if the error is random, it cannot be predicted
and thus cannot be eliminated.

53. Robot Safety
• Safety is the method to avoid accidents.
• Industrial robot must follow the Isaac Asimov’s First Law of Robotics: “a
robot shall not harm a human being.”
• The cause of human injury in a robotic environment vary and include the
following:
▫ Parts of the body being caught
▫ Being struck by a part or robot gripper.
▫ Falling from equipment or structure
▫ Slipping or tripping on walking or working surfaces
▫ Exposure to dangerous levels of heat or electricity
▫ Excessive physical strain

54. Robot Safety
• Safety monitoring involves the use of sensors to indicate conditions or
events that are unsafe or potentially unsafe.
• The objectives of safety monitoring include not only the protection of humans
who happen to be in the cell, but also the protection of the equipment in the
cell.
• The sensors used in safety monitoring range from simple limit switches to
sophisticated vision systems that are able to scan the workplace for
intruders and other deviations from normal operating conditions.

55. Robot Safety
• Great care must be taken in workcell design to predict all possible accidents
that might occur during the operation of the cell, and to design safeguards
to prevent or limit the damage.
• The National Bureau of Standards defines three levels of safety sensor
systems in robots:
▫ Level 1
to detect that an intruder has crossed the workcell perimeter without regard to
the location of the robot.
▫ Level 2
to detect the presence of an intruder in the region between the workcell
perimeter and the limit of the robot workspace.
▫ Level 3
provide intruder detection inside the workspace of the robot.

56. Robot Safety
Three Levels of Robot Safety Sensor System

57. Robot Safety
• There are two common sensors for robot safety system are pressure
sensitive floor mats and light curtains.
• Pressure sensitive mats are area pads placed on the floor around the
workcell that sense the weight of someone standing on the mat. It can be
used for Level 1 or 2 system.
• Light curtains consist of light beams and photosensitive devices placed
around the workcell that sense the presence of an intruder by an
interruption of the light beam. It can be used for Level 1 system.
• For Level 3 safety system, the Proximity sensors could be used and located
on the robot arm.

58. Robot Safety
• The following guidelines are for safe use of robots in a production
environment which given by K. M. Blache in Industrial Practices for Robotic
Safety (1991):
▫ If the robot is not moving, DO NOT assumes it is not going to move.
▫ If the robot is repeating a pattern, DO NOT assumes it will continue.
▫ Always be aware of where you are in relationship to the possible positions
that the robot may reach.
▫ Be aware if there is power to the actuators. Indicator lights will be on when
there is power to the actuators.
▫ Limit switches or software programming will not be used as the primary
safeguard.
▫ Teaching, programming, servicing, and maintenance are the only
authorized reasons for entry into the work envelope.

59. Robot Safety
▫ Safeguards with at least one level of redundancy will be present when
employees are required to enter the work envelope.
▫ Never climb on, over, or under a barrier for any reason.
▫ Before activating power to the robot, employees should be aware of what it
is programmed to do, that all safeguards are in place, and that no foreign
materials are present within the work envelope.
▫ Eliminate any source of stored energy prior to entry into the work envelope.
▫ Notify supervision immediately when any unexpected interruption to the
normal robot work cycle occurs.
▫ Servicing should never occur within the work envelope with power on to the
robot.
▫ Report any missing or defective safeguard to supervision immediately.
Check all safeguards at the beginning of each shift.