ISE 370 Industrial Automation Instructor: Thomas Koon

1
ISE 370 Industrial Automation Instructor Thomas
Koon

• Introduction To Robotics

2
Introduction

• The main purpose of this discussion is to provide
  a very basic understanding of Robotics, and how
  to apply that knowledge to our lab using the
  ADEPT Robot in Lab B-9

3
Topics of Discussion

• Overview of Robotics
• Classification and application of robotics
• Robot components and subsystems
• Kinematics and inverse transformation
• Control of actuators in robotics systems
• Robot sensory devices

4
What is a Robot?
"A reprogrammable, multifunctional manipulator
designed to move material, parts, tools, or
specialized devices through various programmed
motions for the performance of a variety of
tasks" Robot Institute of America, 1979
5
Robots Hollywood Fiction vs. Real-World Fact
6
Why Use Robots?

• To save money?
• To save people?

7
Robot Concepts
Notion derives from 2 strands of thought
Humanoids -- human-like Automata -- self-moving
things Robot -- derives from Czech word
robota Robota forced work or compulsory
service Term coined by Czech playwright Karel
Capek 1921 play R.U.R (Rossums Universal
Robots)
8
Robot Concepts
Current notion of a Robot Programmable
Mechanically capable Flexible One working
definition of robot physical agent that
generates intelligent connection between
perception and action
9
Advantages of Machines

• Do not tire or grumble
• Higher quality.
• Repeatable performance
• Stronger, faster, more accurate
• More productive.
• Work 24 hours each day
• Immune to dangerous environment.

10
Advantages of People

• Adaptable to problems and environments.
• Wide range of sensory inputs, with pattern
  recognition.
• Make decisions, set priorities and define goals.
• Investigate new techniques.
• Easy to program.

11
Some Current State-of-the-Art Robots
12
Robot Applications
13
ROBOT KINEMATICS

• Kinematics is the science of motion.
• Kinematics is important in robots, used to
  model
• Mechanisms
• Actuators
• Sensors
• from Greek kinema movement
• Forward kinematics is the transformation from
  joint space to Cartesian space
• Inverse kinematics solves for the joint angles
  given the desired position and orientation in
  Cartesian space

14
Forward Reverse Kinematics

• Forward Kinematics For a given set of joint
  displacements, the end-effector position and
  orientation can be calculated.

Inverse Kinematics For a given set of
end-effector position and orientation, joint
displacements are computed.
15
Rotational Transforms
Rotation about a single axis
16
Joints Links
17
Link Frame Assignments
Denavit-Hartenberg notation
18
Joints in Zero Position
19
Tool Frame to Base
Multiplication of these matrices leads to the
complete transformation
20
Possible Robot Classifications

• Power Source?
• Classification by Level of Technology
• Arm Configuration?
• Classification by Controller
• Application?

21
Robotic Power Sources

• Electric - Stepper motors (for economy) or servo
  motors (for precision)
• Hydraulic For Power
• Pneumatic - For Speed
• Vacuum For pick and place operations

22
Level of Technology

• 3 current levels of technology now used by
  robots
• Low technology robots are nonservo-controlled.
• 2. Medium technology robots use point to point
  controllers.
• 3. High technology robots use continuous-path
  controllers.

23
Robotic Arm Configuration

• Five recognized arm configurations
• Rectangular (or Cartesian) Coordinates
• Cylindrical Coordinates
• SCARA
• Polar Coordinates
• Jointed Arm (or revolute-coordinates, articulate,
  or anthropomorphic).

24
Cartesian Configuration (TTT)
3 Linear Axis
25
Cylindrical Configuration (TTR, RTR, RRT)
26
SCARA Configuration (RRT)
27
SCARA
Selective Compliant Assembly Robot Arm
In general, traditional SCARAs are 4-axis robot
arms, i.e., they can move to any X-Y-Z coordinate
within their work envelope. There is a fourth
axis of motion which is the wrist rotate
(Theta-Z).
28
Polar Configuration (RRT)
29
Jointed arm/ Revolute Configuration (RRR)
30
Classification by Controller

• Three basic types of robot controllers
• Limited Sequence
• Point to Point
• Continuous Path.

31
Comparisons
32
Robotics Applications
33
Industrial Automation and Robots

• While industrial robots and automated machines
  are usually treated as two separate topics, most
  industrial robots work in cooperation with other
  automated machines.

34
Robot Communications

• LAN - is short for "local area network
• MAP - stands for "manufacturing automation
  protocol" it is a communications standard
  developed for General Motors.
• TOP - is an acronym for "technical and office
  protocol," was developed for use in office
  automation by Boeing Computer Services

35
Automated Machines

• Automated machines classes hard automation and
  flexible automation machines.
• Hard automation deals with specialized machines
  designed for a specific operation or a narrow
  range of operations.
• Flexible automation deals with relatively
  general-purpose machines, such as the industrial
  robot.

36
An Early Use

• An early automated programmable industrial
  machine was the automatic loom, invented by
  Joseph Marie Jacauard in 1801.

Jacquard showed how powerful it was by using
10,000 punched cards to weave a portrait of
himself in black and white silk
37
Terms

• Computer-aided design (CAD) and computer-aided
  engineering (CAE)
• Computer-Aided Manufacturing (CAM)
• Computer-Aided Robotics (CAR)

38
Robot Components

• Robots use arms, end effectors (grippers), drive
  mechanisms, sensors, controllers, gears and
  motors to perform the human-like functions
  necessary to perform their jobs

39
Robot Components

• Arms
• Robot arms come in all shapes and sizes. The arm
  is the part of the robot that positions the
  end-effector and sensors to do their
  pre-programmed business.

• Many (but not all) resemble human arms, and have
  shoulders, elbows, wrists, even fingers. This
  gives the robot a lot of ways to position itself
  in its environment. Each joint is said to give
  the robot 1 degree of freedom.

40
Robot Components
Degrees of freedom
So, a simple robot arm with 3 degrees of freedom
could move in 3 ways up and down, left and
right, forward and backward. Most working robots
today have 6 degrees of freedom.
Humans have many more degrees of freedom. Most
jointed-arm robots in use today have 6 degrees of
freedom
41
Degrees of Freedom
42
Links
Robot links are considered to be rigid and
inflexible. It is the link geometry which is used
to determine the relative position of the
kinematic coordinate frames.
The position of a robots end-effector can be
described in two ways, in Cartesian coordinates
relative to its base frame and in joint
coordinates.
43
2 Most Common Joints
Prismatic (linear) Revolute
(Rotary)
44
Types of Joint
45
Robot Components
AXIS OF ROTATION
X, Y, Z, Are 3 of the degrees of freedom that
robots perform. Most arms move according to
Cartesian coordinates
46
Robot Components
End-effector
The end-effector is the "hand" connected to the
robot's arm. It is often different from a human
hand - it could be a tool such as a gripper, a
vacuum pump, tweezers, scalpel, blowtorch - just
about anything that helps it do its job. Some
robots can change end-effectors, and be
reprogrammed for a different set of tasks.
47
Robot DC Motors
Parts of a 2-Pole DC Motor

• An armature or rotor
• A commutator
• Brushes
• An axle
• A field magnet
• A DC power supply of some sort

48
Stepper Motors

• Stepping motors can be viewed as electric motors
  without commutators.. All of the commutation must
  be handled externally by the motor controller.
  Most stepping motors can be stepped at audio
  frequencies, allowing them to spin quite quickly,
  and with an appropriate controller, they may be
  started and stopped "on a dime" at controlled
  orientations.

49
Robotics Sensors Controllers
Sensors collect all the information a robot
needs to operate and interact with its
environment.
Controllers interpret all the input from the
sensors and decide how to act in response.
50
Robotics Sensors Controllers
Sensors control of a manipulator or industrial
robot is based on the correct interpretation of
sensory information. This information can be
obtained either internally to the robot (for
example, joint positions and motor torque) or
externally using a wide range of sensors.
51
Sensor Types
4 Basic Sensor types 1. Tactile sensors respond
to contact forces with another object 2.
Proximity sensors indicate when an object is
close to another object (within sensor range) 3.
Range sensors measure the distance from the
object to the sensor 4. Machine vision - views
the workspace and interprets what it sees used
primarily for inspection, part identification
52
Sensor Types
Tactile Proximity
Range Machine Vision
53
Mobile Sensor Types

• Some Basic sensor types
• Light sensors which measure light intensity.
• Heat Sensors which measure temperature.
• Touch sensors which tell the robot when it bumps
  into something.
• Ultra Sonic Rangers which tell the robot how far
  away objects are.
• And gyroscopes which tell the robot which
  direction is up.

54
Rotary Shaft Encoders
Direct (absolute) read out v.s, Pulse
55
Robotics Sensors controllers
Motion control is the process of computer
controlled kinetics-- the foundation of robotics.
CNC (computer numeric control) is an antiquated
term for this process, recalling an era when
programmers entered the numeric commands and
coordinates for each machine move.
56
Industrial Robots

• The industrial robot is intended to serve as a
  general-purpose unskilled or semiskilled laborer.
• An industrial robot generally has a single
  manipulator (arm), a wrist, and a gripper (hand).

57
Industrial Robot Types
Rectangular-coordinates robots can move up and
down, back and forth, and in and out.
Polar-coordinates robots rotate up and down,
rotate around, and moves in and out.
58
Characteristics of a Robot
59
Standards

• Robotics Industries Association (RIA)
• SME/RI