ME 4135 – Robotics and Control
An Introduction
Dr. Richard Lindeke
203 Engineering Building
726-7947; rlindek1@d.umn.edu
Contact Details
• Course Website:
http://www.d.umn.edu/~rlindek1/ME4135_11/CoverPage.htm
• Office Hours: 11:30 – 12:30 MWF
• Tentative Exam Dates:
– Midtern 1: Monday 8 Oct
– Midterm 2: Friday 16 Nov
– Final: Wednesday Dec 19 (12 N – 1:55P)
Outline
 Some General Thoughts
 Production Systems & the “Tenets of Automation”
 Pose Control – Fixed Vs Flexible Automation
 System Synchronization
 System Balance
 The “Problems of Robotics”
 The Robot is a System – by definition!
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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 Some Applications:
(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
From: Robotic Industries Association (Posted 07/30/2012)
North American Robotics Industry Posts Best Quarter Ever,
According to New Statistics from RIA
Ann Arbor, Michigan – North American robotics companies
sold more industrial robots in the second quarter of 2012
than any previous quarter in history, according to new
statistics released by Robotic Industries Association (RIA), the
industry’s trade group.
A total of 5,556 robots valued at $403.1 million were sold
to North American companies, a jump of 14% in units and
28% in dollars over the same quarter in 2011. Orders in the
first half of 2012 totaled 10,652 robots valued at $747
million, increases of 20% in units and 29% in dollars over the
same period last year.
From: Robotic Industries Association (Posted 07/30/2012)
Orders for spot welding robots, used primarily in
automotive solutions, jumped 68% in the first half of
2012. Other big jumps were seen in coating & dispensing
(+42%), arc welding (+20%), and assembly (+19%). Material
removal orders, a smaller application area, rose 364 percent.
Automotive related orders accounted for 65% of units and
64% of dollars in the first half of 2012. This represents sharp
gains of 44% in units and 56% in dollars over the opening half
of 2011.
U.S.A.’s Robotic Usage
RIA estimates that some 220,000 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.
With So many Robots in Use, we need effective
Project Management for Automated Systems
Defining Automation:
– Automation is the technology concerned
with the application of complex mechanical,
electronic and computer-based (computercontrolled) systems to the operation and
control of production
 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)
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
Some General Thoughts on 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
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•
•
•
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Productivity Gains
Labor Replacement
Improved Quality, Repeatability & Reliability
Increased Production Capabilities
Quicker Changeovers
Project Management for Automated Systems –
what to consider
STEP 1
Quantify Overall System Needs:
– Number of Parts per hour (Production Rate!)
– Product Variety
– Part Size
– Part Shape
– Part Weight, etc
Project Management for Automated Systems –
what to consider
STEP 2
Find Special Needs:
– Robot Tooling and Machine Fixturing
– Sensors for Pose Control or Decision-making
– Communication Requirements (Machine to
Machine)
Project Management for Automated Systems –
what to consider
STEP 3
Determine Control Hierarchy:
– Isolated Actions
– Master/Slave(s)
– Event Driven Response – under higher or parallel
control
Project Management for Automated Systems –
Final Actions
STEP 4:
Build and/or Program Individual Units:
– Robot Path Control
– Machine Tool Codes
– AGV Paths/Controls
– ASRS Designs/Controls
– Communication Network
– Relays/Sensors, etc.
“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
What Are the “BIG Problems” for a
robot engineer
• Where Am I (Now)
– This is the Forward Kinematics Problem
• Where Am I going
– This is a Forward/Inverse Kinematics Problem
• How will I get there
– This is a combination of the two needs:
• Path Planning
• Force/Torque Kinetics and (Servo) Control
The Robot System Contains 5 Major Subsystems
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•
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•
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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)
Cantilevered Type
Y0
J1
Gantry Type
J3
J2
Z0
X0
Cylindrical Types (RPP or PRP)
P-R-P//R-P-P
Configuration
Spherical Types (RRP)

R
Z0
Y0
X0
Articulating Type (RRR)
Z0

L2
3
2
Y0
L1
X0
1
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!