ME 4135 – Robotics and Control An Introduction

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ME 4135


Robotics and Control

An Introduction

Dr. Richard Lindeke

203 Engineering Building

726
-
7947; rlindek1@d.umn.edu

Outline


Some General Thoughts


uses and statistics


Project
Management for automated Systems & Machines


What
to consider


Working
intelligently with the systems


The Overriding “Tenets of Automation”


Pose Control


Fixed Vs Flexible Automation


System Synchronization


System Balance


The Robot as a System


by definition!


Manipulator


Power System


Controller Schemes


End of Arm Tooling


Sensors (environmental)

Just Consider This:


Thank goodness robots are now at the point where using
them is nearly the business equivalent of upgrading from a
typewriter to a personal computer. Price has virtually been
eliminated from the cost justification exercise. Today you get so
much value in terms of software and technology, reliability and
accuracy, that robots are affordable at any size.



Just as Joe
Engelberger
, the ‘‘Father of Robotics,’‘ has said so
many times


when looking at solving manufacturing
problems, ask the question: ‘‘Do you think a robot could …?’‘ It
was a good question 40 years ago, and even better today with
all the new technology.

Just Consider This:

(from The British Automation & Robot Association)

Search by [Automation/Robot] Application Area:
Arc / Gas / Laser / Spot
Welding

Assembling

Bio
-
Chemistry and Hazardous Applications

Cutting / Grinding /
Polishing

Dispensing / Painting / Sealing / Spraying

Handling Operations / Machine
Tending /
Moulding

Inspection / Measurement / Testing

Laser / Water Jet Cutting

Loading / Unloading

Packaging / Palletizing



Search by
[
User] Industry:
Aerospace

Agriculture / Hunting / Forestry / Fishing

Basic Metals / Fabricated Metal Products

Beverages / Food / Tobacco Products

Ceramics

Chemicals / Fuels

Clocks / Medical / Optical / Precision / Watches

Communications / Radio / Television

Computing / Electronics / Software

Construction

Cork / Wood (excluding furniture)

Education

Electric / Gas / Water Supply

Furniture

Minerals (non
-
metallic)

Mining / Quarrying

Motor Vehicles

Paper / Printing /
Publishing / Recorded Media

Pharmaceuticals

Plastic / Rubber

Research &
Development

Textiles


Ann Arbor, MI


North American based robotics companies
reported strong growth in 2010, posting the best year since
2007, according to new statistics released by Robotic
Industries Association (RIA), the industry’s trade group.



North American robot suppliers reported orders of 13,174
robots valued at $845.6 million from North American based
companies, increases of 39% in units and 49% in
dollars.


When orders from customers outside North America
are included, the totals are 15,860 robots valued at $993.2
million, gains of 52% in units and 58% in dollars.

North American Robotics Companies Post Best Year Since
2007

From:
Robotic Industries Association

(Posted 02/07/2011)


The automotive industry, including OEMs and their suppliers,
accounted for 51% of the North American orders in
2010.


Orders to this sector, the largest user in North America,
were up 34% in units.




Non
-
automotive orders jumped 46%, fueled by large gains in
orders from metalworking (+90%),
semiconductor/electronics/photonics (+66%), plastics & rubber
(+57%), food & consumer goods (+47%), and life
sciences/pharmaceuticals/biomedical/medical devices (+26%).

2010 Robot Sales (U.S.A.)

Now in 2011 …

North American Robot Orders Jump 41% in First Half of
2011


Robotic Industries Association

Posted 07/29/2011
Second
quarter is strongest quarter in six years
: Fueled by its best quarter
in six years, the North American robotics industry jumped 41% in
the first half of 2011.



A total of 8879 robots valued at $577.8 million were ordered by
North American companies in the first six months of the
year.


When orders from outside North America are added, the
totals are 10,476 robots valued at $667.9 million.





The second quarter was particularly strong, posting gains of 50%
in units and 55% in dollars over the same period in 2010.


RIA estimates that some 200,000 industrial
robots are now used in the United States,
placing the United States second only to
Japan in overall robot use.


More than one
million industrial robots are used worldwide.

U.S.A.’s Robotic Usage

Project Management for Automated Systems


Defining Automation:


Automation is the technology concerned
with the application of complex mechanical,
electronic and computer
-
based (computer
-
controlled) systems to the operation and
control of production

Project Management for Automated Systems


Automation includes:


Automatic Machine Tools, Forges and
Molders
for
workpiece

processing (CNC & DNC)


Material Handling Equipment (ASRS’s, AGV’s, Reactive
Conveyors)


Automated Assembly Machines


Feedback Control Systems/System Sensors


Process Controllers (PLC’s)


Automated Data Collection Systems (AIDC)


Automated Data Reporting Systems (MRP)


Project Management for Automated Systems


what to consider


The development of an Automated System is a 4
step process:


System problem analysis for overall needs


Determination of special needs


Design of control hierarchy


Building/programming of individual
components



Working Intelligently with a Production
System


Does Variety (types) or Piece Count (volume)
dominate?


Consider
Fixed Automation vs. Flexible Automation


Should we Consider Humans?


Typically
, making it easier for automation makes it easier
for humans (especially true for assembly)


Cost Justification of the system


Productivity Gains


Labor Replacement


Improved Quality, Repeatability & Reliability


Increased Production Capabilities


Quicker Changeovers

Project Management for Automated Systems


what to consider


Quantify Overall System Needs:


Number of Parts per hour (Production Rate!)


Product Variety


Part Size


Part Shape


Part Weight, etc

STEP 1

Project Management for Automated Systems


what to consider


Find Special Needs:


Robot Tooling and Machine
Fixturing


Sensors for Pose Control or Decision
-
making


Communication Requirements (Machine to
Machine)


STEP 2

Project Management for Automated Systems


what to consider


Determine Control Hierarchy:


Isolated Actions


Master/Slave(s)


Event Driven Response


under higher or parallel
control

STEP 3

Project Management for Automated Systems


Final Actions


Build and/or Program Individual Units:


Robot Path Control


Machine Tool Codes


AGV Paths/Controls


ASRS Designs/Controls


Communication Network


Relays/Sensors, etc.


STEP 4:

“Tenets of Automation”



Or what must be assured
when Machines replace Humans

Pose Control
: is a principle that states that each degree
of freedom of a machine, tool, product or process
must be fully known or accounted for at all times
for the (high quality) production systems to
operate.


Degree of Freedom

is (in this physical sense):


a set of positional bits (X, Y or Z)


a set of Rotational bits (Roll, Pitch or Yaw)


Full POSE Control Requires 6
dof

from the machine!

“Tenets of Automation”



System
Synchronization

(timing control) of
operations must be maintained:


this requires that the sequence and timing
of each movement during the process
activity must be known and controlled.


This includes part counting, machine and
product arrivals and departures, completed
and closed communication sequences, etc.




“Tenets of Automation”


System Balance
:



Each step in a process must be
appropriately sized to complete its tasks
within the overall system processing
requirements.



Thus, no process should be slower/smaller
(or faster/larger) than its predecessor or
followers without accounting for product
accumulation within the system.


Achieving Automation


Fixed vs Flexible


In Fixed Automation Systems


POSE CONTROL is
imposed

by stops, cams,
rotators, etc


SYNCHRONIZATION is controller by in
-
feed supply,
part feeders, hoppers, pallet movers, etc


BALANCE is controlled by (Overall System) design

Achieving Automation


Fixed vs Flexible


In Flexible Automation Systems


POSE CONTROL is achieve by sensing and
adaptation by the machines and product in the
system


SYNCHRONIZATION is by adapting to the changing
needs of the feed stock and throughput demand


BALANCE is by design over extended time horizon,
machines can be reprogrammed (on
-
line in Real
Time) for changing part mix

The Robot System Contains 5 Major Sub
-
systems


Manipulator


Power System


Control


End
-
of
-
Arm Tooling


Environmental Sensors


The Robot System


The Manipulator


includes an Arm part and a
Wrist part


consists of joints (revolute or prismatic),
actuators, and kinesthetic (positional) sensors


Arm Types
:


Cartesian


Cylindrical


Spherical


SCARA
(selectively compliant assembly robots)


Articulating Arms

Cartesian Types (PPP)

X
0

Y
0

Z
0

J1

J2

J3

Gantry Type

Cantilevered Type

Cylindrical Types (RPP or PRP)

P
-
R
-
P//R
-
P
-
P

Configuration

Spherical Types (RRP)

R



X
0

Y
0

Z
0

Articulating Type (RRR)


3


1


2

L
2

L
1

Z
0

X
0

Y
0

SCARA Type (RRRP)

Manipulator Wrists

Spherical and/or RPY
variants
--

Idealized

…To Practical
Realizations of 3
dof

Wrists

The Robot System


The Power Systems


Pneumatic for light loads at elevated speed


Hydraulic for heavy loads or very high speeds


Electric Servo for general applications


The Robot System


The Controllers


Bang
-
Bang: are mechanically programmed (movement to stops) and
usually one
-
axis
-
at
-
a
-
time



Point
-
to
-
point servo: feedback of joints positions as moves from
point A to B are run


no control of the path between A and B only
end points are assured



Servo w/ Path Control: the motion is controlled completely between
point pairs including positions and orientation to follow desired
space curves



Autonomous Control: Device control that allows paths to be
determined in ‘real time’ as the devices moves and interprets various
sets of sensory inputs to create ‘intelligent’ paths as it moves



The Robot System


The End of Arm Tooling
--

their complexity of task
dictates the type of control scheme that is required


Grippers/Hands/spot welders


Sensor Arrays (static reading)


Sensors (active scanning)


Ladle/Hooks


Routers/Grinders/Drills


Spray Guns/Torches

The Robot System


Environmental Sensors


devices that give higher level information for
program control and or path planning



Thus, Robots are Systems requiring design
choices
at
5.2
levels!