Date:

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Mechatronics Robotics

• Dr Vesna Brujic-Okretic
• Room 11cBC03 or
• MSRR Lab.
• Ext. 9676 or 9681
• Email mes1vb_at_surrey.ac.uk

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Recommended Literature

• Course Manual
• Bradley, D.A., Dawson, D., Burd, N.C., Loader,
  A.J. Mechatronics Electronics in products and
  processes. Chapman and Hall, London, First
  ed.1991
• Fraser, C., Milne, J. Integrated Electrical and
  Electronic Engineering for Mechanical Engineers.
  McGraw-Hill, London 1994
• Bolton, W. Mechatronics Electronic control
  systems in mechanical engineering. Longman
  Scientific Technical, London, 1995.
• Lippiatt,A.G. and Wright, G.G.L. The Architecture
  of Small Computer Systems, Second Edition,
  Prentice-Hall International, 1986 ISBN
  0-13-044736-6

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Course Outline

• Introduction to Mechatronics
• concept
• design philosophy
• Building blocks processes of a mechatronic
  system
• Microprocessor System
• Input/Output Devices - Peripherals
• Polling Interrupts
• Digital Analogue Interfacing
• Case Studies

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Course Outline

• Robotics
• Introduction to Robotics
• Robot Control Programming
• Robot Kinematics
• External sensors intelligent robots
• Revision
• Examination

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We will touch upon...

• Transducers
• Actuators
• Analogue electronics
• Digital electronics
• but the emphasis will stay on
• Integrated System Design
• philosophy and practice

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Introduction

• transistor invented in 1948
• integrated circuit technology - a leap forward
• micro-miniaturisation - an on-going process
• in the 70s - microprocessor (mP) appeared on the
  market
• revolutionised the intelligence incorporated in
  consumer products industrial systems
• In the 80s - a true explosion in
  microprocessor-based products happened

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Where are these products found?

• consumer sector
• CD players
• camcorder
• auto-focus, auto exposure camera etc.
• commercial sector
• automated teller machine (ATM) etc.
• industrial sector
• co-ordinate measuring machines (CMM)
• flexible manufacturing system (FMS)
• automotive industry
• active suspension systems etc.

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• architecture
• e.g. automatic blinds control
• staff recognition (security) etc.
• Countless applications in
• system monitoring
• data handling
• data presentation
• control
• etc.

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System Approach

• the so-called system approach to design has
  emerged
• Japanese introduced the term MECHATRONICS
• additional knowledge required of mechanical
  engineers to understand the basics of how these
  electronic elements work
• they must now be competent in the application of
  mP devices

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Traditional vs Mechatronic a
Comparison

• Traditional approach Mechatronic approach
• Centralized computer Distributed processing
• control
• Sequence control Parts of process capable
• predominates of individual control
• Whole process controlled mP based PLCs provide
• by relay logic degree of intelligence
• Inspection/QA stages In-process automatic
• towards the end of process inspection

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Traditional vs Mechatronic a
Comparison

• Traditional approach Mechatronic approach
• Bulky system Compact
• Complex mechanisms Simplified mehcanisms
• Non-adjustable movements Programmable movements
• Constant speed drives Variable speed drives
• Mechanical synchronisation Electronic
  synchronisation
• Manual controls Automatic programmable
  controls

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Definition(s) of Mechatronics

• means different things to different people -
  depending on their background
• essentially, all definitions amalgamate to
• It is a combination of mechanical engineering,
  electronics, control and computing applied to the
  design and manufacture
• but the whole is more than just the sum of the
  constituent parts
• a systems approach to design had to be adopted
• the overall objectives of the system take the
  priority, rather than the individual elements

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Mechatronic philosophy - a schematic diagram
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Bradley Diagram
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Modules

• The environment module (EM)- external factors
  that influence the operation of the system, e.g.
• temperature, pressure, load factors etc.
• The assembly module (AM)- mechanical structural
  elements incl. housing or mechanisms
• Inputs motion pattern from the actuator
  conditions from the environment module
• state of relevant parameters - sensed from AM
• protecting and keeping the machine components
  together
• dissipation of excess heat
• protection from noise pollution
• elimination of EMI
• meeting aesthetic criteria

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• The measurement modules - collect information
  about the status and condition of the system and
  of the environment
• inputs physical properties of the assembly
  (temperatures, angles etc.)
• output dependent on the measurand
• The communication module - transmits information
  between modules within the system
• The processor module - responsible for
  processing, storing and utilising the information
  provided by the interface module and the
  measurement module

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• The software module contains the operating
  instructions and defines the algorithms for the
  processing module
• The actuation module represents the drives or
  actuators which can change the system conditions
• The interface module provides the link between
  this system and others - e.g. man-machine
  interface (MMI) or the graphical user interface
  (GUI). It is therefore at the highest level
• Inputs/outputs include keyboards, touch-screens,
  VDU

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Summary

• Mechatronics is
• the combination of precision mechanical
  engineering, electronics, control engineering and
  computer science in the intelligent control of
  machines and processes.
• A multidisciplinary technology behind so called
  smart components, systems and manufacturing
  facilities
• A design philosophy, an integrated approach to
  engineering design.
• Characteristic of mechatronic devices and systems
  is their in-built intelligence, improved
  performance and greater flexibility. Machines are
  becoming functional computers.

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Case Studies - Examples

• Bathroom scales
• Temperature Control
• Automated Teller Machines
• Flexible Manufacturing Systems
• Air Spring

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CS1 Bathroom Scales
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CS1 Bathroom Scales

• mechanical solution elastic member
• deflection can be transformed into the movement
  of a pointer
• mechanical mechanisms
• mechatronic solution
• platform - load cells - electrical strain gauges
• gauges strained - changed resistance
• small signal input into differential op-amp
• amplified signal input into mP via AD converter
• display driven by mP - e.g. weight calculated
  displayed via LEDs

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Advantages

• flexibility
• durability
• simple mechanical construction
• functionality transferred to electronics
• possibility of adding functionality at low cost
• higher accuracy
• cost - same as conventional

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CS3 Air Spring
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CS3 Air Spring

• advanced adaptive suspension system
• sensors measure
• position
• velocity
• acceleration
• on-board controlling mP - data transfer interval
  20ms
• Pneumatic valves controlled by mP - vary pressure
  in air springs

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CS3 Air Spring

• modes of operation
• static adjusting to loading bay height - stay
  horizontal
• quasi-static cornering, lane-changing, prevents
  from rolling
• dynamic - rough ground - high frequency
  vibrations reduced altering dampers

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Tutorial questions

• 1.1 Compare and contrast the traditional design
  of a watch with that of a mechatronics-designed
  product involving a microprocessor.
• 1.2 Compare and contrast the control system for
  the domestic central heating system involving a
  bimetallic thermostat and that involving a
  microprocessor.
• 1.3 List as many mechatronic devices and products
  as you can. You may find the following categories
  helpful consumer, commercial, industrial
  automotive
• 1.4 Select one system from each group found in
  question 1.3 and try to identify and comment on
  the eight design modules highlighted in the
  lecture.

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Case Studies on offer

• EOS Camera
• Prosthetic Hand
• Automotive Sensors
• Fly-by-wire

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Case Study

• In groups of three or four, research one case
  study. You should write a summary report of no
  more than 2 sides of A4 containing a brief
  outline of the system, its mode of operation and
  include key features.
• You should emphasise the systems in-built
  intelligence, and comment on the improved
  performance and greater flexibility over previous
  systems. Include Bradley diagram identify
  modules
• You should be prepared to give a 15 minute
  presentation to your peers on your research
  findings.