# Introduction to Robotics

Mechanics

Oct 31, 2013 (4 years and 6 months ago)

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Introduction to Robotics

Dept. of Computer Science

Technion

Winter Semester, 2004
-
5

I2R Information Sheet

Instructor: Hector Rotstein

Phone: 054
-
2151054.
Evenings

only!

Office hours:

We: 17:30
-
18:30

Fri: 11:30
-

12:30

(
appointment only
)

E
-
mail: hector@ee.technion.ac.il

I2R Information Sheet

TA Name

Evgeny Magid

Phone

4340

Office Hours

Email

evgenue@cs

Mailbox

Bibliography

John Craig,
“Introduction to robotics,”

G. Dudek and M. Jenkin, “
Computational
Principles of Mobile Robotics
,” Cambridge
University Press.

Handouts

Course Objectives

At the end of this course, you should be able to:

Describe and analyze rigid motion
.

Write down manipulator kinematics and operate
with the resulting equations

Solve simple inverse kinematics problems.

Select sensors for performing robotic tasks

Use sensors to compute robotics localization

Syllabus

A brief history of robotics. Coordinates and
Coordinates Inversion. Trajectory planning.
Sensors. Actuators and control. Why robotics?

Basic Kinematics. Introduction. Reference
frames. Translation. Rotation. Rigid body motion.
Velocity and acceleration for General Rigid
Motion. Relative motion. Homogeneous
coordinates.

description and connection. Manipulator
kinematics. The workspace.

Syllabus (cont.)

Inverse Kinematics. Introduction. Solvability.
Inverse Kinematics. Examples. Repeatability and
accuracy.

Basic Dynamics and Control. Introduction.
Definitions and notation. Laws of Motion. Robot
control.

Trajectory generation. Introduction. General
considerations. Path generation.

Introduction to mobile robots. Mobile Robots hw.

Sensing and localization

There will be six homework assignments, one
mid
-
term and project.

Tests are open book. The homeworks will count
4% each towards the final grade, the project 40%
and the final 36%.

The worst homework will be given 20% of the
normal weight, while the best will be given
180% of the normal weight.

Collaboration in the sense of discussions is
allowed. You should write final solutions and
understand them fully. Violation of this norm will
be considered cheating, and will be taken into
account accordingly.

Can work alone or in teams of
2

You can also consult additional books and
references but not copy from them.

Required homework will be due before the
beginning of practice, at the course mailbox.

Late homework will be accepted up to one week
of 80% and loose 10% for each delay day after
the first one. However, bonus problems must be
handed in on their due date.

Robot Examples

The Three Laws of Robotics

A robot may not injure a human being, or, through
inaction, allow a human being to come to harm.

A robot must obey the orders given it by human
beings except where such orders would conflict
with the First Law.

A robot must protect its own existence as long as
such protection does not conflict with the First or
Second Law.

Zeroth law: A robot may not injure humanity, or,
through inaction, allow humanity to come to harm

Robot Demos

A Brief History of Robotics

The word
robot

introduced by Czech playwright
Karel Capek: robots are machines which
resemble people but work tirelessly.

His view is still to be fulfill!

Best soccer player ever

Best robot player ever

A Brief History of Robotics II

Definition
:

a robot is a software
-
controllable mechanical device that
uses sensors to guide one or more end
-
effectors through
programmed motions in a workspace in order to
manipulate physical objects.

Today’s robots are not
androids

built to impersonate
humans.

Manipulators are
anthropomorphic

in the sense that they
are patterned after the human arm.

Industrial robots: robotic arms or
manipulators

History of Robotics (cont.)

Early work at end of WWII for handling

Computer numerically controlled machine tools
for low
-
volume, high
-
performance AC parts

Unimation (61):

built first robot in a GM plant.
The machine is programmable.

Robots were then improved with sensing: force
sensing, rudimentary vision.

History of Robotics (cont.)

Two famous robots:

Puma
. (Programmable Universal Machine for
Assembly). ‘78.

SCARA.

(Selective Compliant Articulated Robot
Assembly). ‘79.

In the ‘80 efforts to improve performance:
feedback control + redesign. Research dedicated
to basic topics. Arms got flexible.

‘90: modifiable robots for assembly. Mobile
autonomous robots. Vision controlled robots.
Walking robots.

Robot Classification

Robotic manipulator: a collection of

inter
-

connected by flexible joints. At the end of the robot
there is a tool or
end
-
effector.

Drive Technology.

Which source of power drives
the joints of the robot.

Work
-
envelope geometries.

Points in space
which can be reached by the end
-
effector.

Motion control method.
Either point
-
to
-
point or
continuous path

The Course at a Glimpse:
Kinematics

F(
robot variables
) =
world coordinates

x = x(

1
,

,

n
)

y = y(

1
,

,

n
)

z = z(

1
,

,

n
)

In a “cascade” robot, Kinematics is a single
-
valued
mapping.

“Easy” to compute.

Kinematics: Example

1
=

,

2
=r

1

r

4.5

0

50
o

x = r cos

y = r sin

workspace

Inverse Kinematics

G(
world coordinates
) =
robot variables

1
=

1
(x,y,z)

N

=

N
(x,y,z)

The inverse problem has a lot of geometrical
difficulties

inversion may not be unique!

Inverse Kinematics: Example

2

1

Make unique by constraining
angles

Trajectory Planning

Get from (
x
o
, y
o
, z
o
) to (
x
f
, y
f
, z
f
)

In robot coordinates:

o

f

Planning in robot coordinates is easier,
but

we
loose

visualization.