ME 4135 – Robotics and ControlAn Introduction

Dr. Richard Lindeke203 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

by: 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 2011Robotic 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 Molder 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 – consists of joints (revolute or prismatic), actuators,

and kinesthetic (positional) sensors– Types: • Cartesian• Cylindrical• Spherical• SCARA (selectively compliant assembly robots)

• Articulating Arms

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 levels!