Introduction to Engineering Electronics

1
Lecture 9 Motors and Actuators

• Working At The Boundary Between EE/CSE/EPE,
  Mechanical and Materials Engineering

2
Magnetism

• One of the first compasses, a fish shaped iron
  leaf was mentioned in the Wu Ching Tsung Yao
  written in 1040
• Trinity College, Dublin

3
Animal Magnetism

• A frog suspended in an intense magnetic field
  all of us are paramagnetic
• Much money is wasted on magnetic therapy

4
Electromagnetic Revolution

• These four equations epitomize the
  electromagnetic revolution. Richard Feynman
  claimed that "ten thousand years from now, there
  can be little doubt that the most significant
  event of the 19th century will be judged as
  Maxwell's discovery of the laws of
  electrodynamics"

5
Magnetic Attraction

• It is possible to produce motion using magnetic
  attraction and/or repulsion
• Either permanent magnets or electromagnets or
  both can be used

6
Magnetic Attraction and Repulsion

• One of the many facts we all recall from our
  earliest science education

7
2 Minute QuizName______Sec_____Date______

• True or false, unlike magnetic poles attract and
  like magnetic poles repel one another.

8
DC Motors

• The stator is the stationary outside part of a
  motor. The rotor is the inner part which rotates.
  In the motor animations, red represents a magnet
  or winding with a north polarization, while green
  represents a magnet or winding with a south
  polarization. Opposite, red and green, polarities
  attract.

9
DC Motors

• Just as the rotor reaches alignment, the brushes
  move across the commutator contacts and energize
  the next winding. In the animation the commutator
  contacts are brown and the brushes are dark grey.
  A yellow spark shows when the brushes switch to
  the next winding.

10
DC Motor Applications

• Automobiles
• Windshield Wipers
• Door locks
• Window lifts
• Antenna retractor
• Seat adjust
• Mirror adjust
• Anti-lock Braking System

• Cordless hand drill
• Electric lawnmower
• Fans
• Toys
• Electric toothbrush
• Servo Motor

11
Beakmans Motor

• A simple DC motor made with a battery, two
  paperclips, a rubber band and about 1 meter of
  enameled wire.

12
Brushless DC Motors

• A brushless dc motor has a rotor with permanent
  magnets and a stator with windings. It is
  essentially a dc motor turned inside out. The
  control electronics replace the function of the
  commutator and energize the proper winding.

13
Brushless DC Motor Applications

• Medical centrifuges, orthoscopic surgical tools,
  respirators, dental surgical tools, and organ
  transport pump systems
• Model airplanes, cars, boats, helicopters
• Microscopes
• Tape drives and winders
• Artificial heart

14
Full Stepper Motor

• This animation demonstrates the principle for a
  stepper motor using full step commutation. The
  rotor of a permanent magnet stepper motor
  consists of permanent magnets and the stator has
  two pairs of windings. Just as the rotor aligns
  with one of the stator poles, the second phase is
  energized. The two phases alternate on and off
  and also reverse polarity. There are four steps.
  One phase lags the other phase by one step. This
  is equivalent to one forth of an electrical cycle
  or 90.

15
Half Stepper Motor

• This animation shows the stepping pattern for a
  half-step stepper motor. The commutation sequence
  for a half-step stepper motor has eight steps
  instead of four. The main difference is that the
  second phase is turned on before the first phase
  is turned off. Thus, sometimes both phases are
  energized at the same time. During the half-steps
  the rotor is held in between the two full-step
  positions. A half-step motor has twice the
  resolution of a full step motor. It is very
  popular for this reason.

16
Stepper Motors

• This stepper motor is very simplified. The rotor
  of a real stepper motor usually has many poles.
  The animation has only ten poles, however a real
  stepper motor might have a hundred. These are
  formed using a single magnet mounted inline with
  the rotor axis and two pole pieces with many
  teeth. The teeth are staggered to produce many
  poles. The stator poles of a real stepper motor
  also has many teeth. The teeth are arranged so
  that the two phases are still 90 out of phase.
  This stepper motor uses permanent magnets. Some
  stepper motors do not have magnets and instead
  use the basic principles of a switched reluctance
  motor. The stator is similar but the rotor is
  composed of a iron laminates.

17
More on Stepper Motors

• Note how the phases are driven so that the rotor
  takes half steps

18
More on Stepper Motors

• Animation shows how coils are energized for full
  steps

19
More on Stepper Motors

• Half step sequence of binary control numbers

• Full step sequence showing how binary numbers can
  control the motor

20
Stepper Motor Applications

• Film Drive
• Optical Scanner
• Printers
• ATM Machines

• I. V. Pump
• Blood Analyzer
• FAX Machines
• Thermostats

21
2 Minute QuizName______Sec_____Date______

• Name one mechatronic device that you own or use
  on a regular basis

22
Switched Reluctance Motor

• A switched reluctance or variable reluctance
  motor does not contain any permanent magnets. The
  stator is similar to a brushless dc motor.
  However, the rotor consists only of iron
  laminates. The iron rotor is attracted to the
  energized stator pole. The polarity of the stator
  pole does not matter. Torque is produced as a
  result of the attraction between the
  electromagnet and the iron rotor in the same way
  a magnet is attracted to a refrigerator door. An
  electrically quiet motor since it has no brushes.

23
Switched Reluctance Motor Applications

• Motor scooters and other electric and hybrid
  vehicles
• Industrial fans, blowers, pumps, mixers,
  centrifuges, machine tools
• Domestic appliances

24
Brushless AC Motor

• A brushless ac motor is driven with ac sine wave
  voltages. The permanent magnet rotor rotates
  synchronous to the rotating magnetic field. The
  rotating magnetic field is illustrated using a
  red and green gradient. An actual simulation of
  the magnetic field would show a far more complex
  magnetic field.

25
AC Induction Motor

• The stator windings of an ac induction motor are
  distributed around the stator to produce a
  roughly sinusoidal distribution. When three phase
  ac voltages are applied to the stator windings, a
  rotating magnetic field is produced. The rotor of
  an induction motor also consists of windings or
  more often a copper squirrel cage imbedded within
  iron laminates. Only the iron laminates are
  shown. An electric current is induced in the
  rotor bars which also produce a magnetic field.

26
AC Induction Motor

• The rotating magnetic field of the stator drags
  the rotor around. The rotor does not quite keep
  up with the the rotating magnetic field of the
  stator. It falls behind or slips as the field
  rotates. In this animation, for every time the
  magnetic field rotates, the rotor only makes
  three fourths of a turn. If you follow one of the
  bright green or red rotor teeth with the mouse,
  you will notice it change color as it falls
  behind the rotating field. The slip has been
  greatly exaggerated to enable visualization of
  this concept. A real induction motor only slips a
  few percent.

27
Huge List of Applications from Hurst

• Aircraft Window Polarizing Drives
• Antenna Positioning and Tuning Devices
• Audio/Video Recording Instruments
• Automated Inspection Equipment
• Automated Photo Developing Equipment
• Automated Photo Slide Trimming Mounting
  Equipment
• Automatic Carton Marking Dating Machines
• Automatic Dying and Textile Coloring Equipment
• Automatic Food Processing Equipment
• Automatic I.V. Dispensing Equipment
• Automatic Radio Station Identification Equipment
• Automotive
• Automotive Engine Pollution Analyzers
• Baseball Pitching Machine
• Blood Agitators
• Blood Cell Analyzer

• Warning Light Flashers
• Railroad Signal Equipment
• Remote Focusing Microscopes
• Resonator Drives for Vibraphones
• ..
• Silicone Wafer Production Equipment
• Solar Collector Devices
• Sonar Range Recorders and Simulators
• Steel Mill Process Scanners
• Tape Cleaning Equipment
• Tape Input for Automatic Typewriters
• Telescope Drives
• Ultrasonic Commercial Fish Detectors
• Ultrasonic Medical Diagnostic Equipment
• Voltage Regulators
• Water and Sewage Treatment Controls
• Weather Data Collection Machines
• Welding Machines
• X-Ray Equipment

28
Stepper Motor from Mechatronics
29
Mechatronics Stepper Motor Continued
30
Mechatronics

• Mechatronics is at the intersection between
  several disciplinary areas, as represented by
  these Venn diagrams

31
What Is Mechatronics?

• Mechatronics is the synergistic integration of
  mechanical engineering, electronics, controls,
  and computers all integrated through the design
  process.
• EXAMPLES
• robots
• anti-lock brakes
• photocopiers
• consumer products (e.g., clothes dryers)
• disk drives

32
MEMS

• Micro-Electro-Mechanical Systems (MEMS) is the
  integration of mechanical elements, sensors,
  actuators, and electronics on a common silicon
  substrate through the utilization of
  microfabrication technology. While the
  electronics are fabricated using integrated
  circuit (IC) process sequences (e.g., CMOS,
  Bipolar, or BICMOS processes), the
  micromechanical components are fabricated using
  compatible "micromachining" processes that
  selectively etch away parts of the silicon wafer
  or add new structural layers to form the
  mechanical and electromechanical devices.

33
MEMS Stepper Motor

• This motor is very much like the other stepper
  motors mentioned above, except that it is 2D and
  very small

34
MEMS

• The potential complexity of the MEMS device
  increases exponentially with the number of unique
  process features and individual structural layers.

35
MEMS Steam Engine

• Water inside of three compression cylinders is
  heated by electric current and vaporizes, pushing
  the piston out. Capillary forces then retract the
  piston once current is removed.

36
MEMS

• Rotary motor
• Steam Engine (single piston)

37
MEMS Gear Trains

• Six gear planar train at various speeds
• Close up of six gear train

38
Power MEMS

• 80 Watt gas microturbine designed and built at
  MIT for MEMS power applications

39
Integrated MEMS

• This six-degrees-of-freedom micro-inertial
  measurement system combines microelectronic
  circuitry top right with a couple of
• micromechanical elements an accelerometer
  center right and gyroscope bottom right.

40
Integrated MEMS

• Types of micromechanical devices that might be
  used in integrated microsystems of the future
  shown clockwise from right include this gear,
  pop-up mirror, mirror assembly, and hinge. The
  gear is part of an assembly that has demonstrated
  torque ratios of up to 3 million to 1. The
  silicon mirror is fabricated flat on the silicon
  wafer, then "popped up" to its raised position
  using the gear assembly.

41
Integrated MEMS

• Sample collection regions for concentration,
  microseparation channels, sensor arrays for
  detection, and an exit region are illustrated in
  schematic of the chemical analysis section of a
  micro-chemlab. Chemicals are detected measuring
  the response of surface acoustic-wave devices to
  a chemical's presence. The photograph is of an
  array of micromachined 3-µm silicon posts in a
  microchannel being studied as a tool for
  enhancing electrokinetically driven liquid
  separations.

42
MEMS Displays

• Iridigm Display -- The iMoD element uses
  interference to create color in the same way that
  structural color works in nature. Microscopic
  structures on butterfly wings and peacock
  feathers cause light to interfere with itself,
  creating the shimmering iridescent colors that we
  see in these creatures. (Used in PDAs)

43
MEMS Displays

• The iMoD element is a simple MEMS device that is
  composed of two conductive plates. One is a thin
  film stack on a glass substrate, the other is a
  metallic membrane suspended over it. There is a
  gap between the two that is filled with air. The
  iMoD element has two stable states. When no
  voltage is applied, the plates are separated, and
  light hitting the substrate is reflected as shown
  above. When a small voltage is applied, the
  plates are pulled together by electrostatic
  attraction and the light is absorbed, turning the
  element black.

44
MEMS Displays

• iMoD elements are minuscule, typically 25-60
  microns on a side (400-1,000 dots per inch).
  Therefore, many iMoD elements are ganged and
  driven together as a pixel, or sub-pixel in a
  color display. The color of the iMoD element is
  determined by the size of the gap between the
  plates. As shown, the blue iMoD has the smallest
  gap and the red has the largest. To create a flat
  panel display, a large array of iMoD elements are
  fabricated in the desired format (i.e. 5" full
  color VGA) and packaged. Finally, driver chips
  are attached at the edge to complete the display.

45
References

• Motor Operation Principles from Motorola
• Basic Stepper Motor Concepts
• MEMS Clearinghouse
• Mechatronics at Rensselaer
• Mechatronics.org
• Beakmans Motor Electronic Instrumentation and
  Fields and Waves I

46
2 Minute QuizName______Sec_____Date______

• Which engineering majors are some interest to
  you? Electrical, Computer Systems, Electric
  Power, Nuclear, Mechanical, Aeronautical,
  Biomedical, Civil, Industrial Management,
  Materials, Chemical, Environmental, Engineering
  Physics

47
Primary Course Goal for IEE

• Assure that each EE and CSE student has a minimum
  of 20 hours of practical electronics and
  instrumentation experience before they begin
  taking disciplinary courses.
• For students with no experience 20 hours
  successfully completing labs
• For students with some experience 20 hours
  completing labs, expanding their knowledge base
  and helping those with less experience
• For students outside of EE and CSE provide a
  working knowledge of electronics

48
2 Minute QuizANSWERS

• True or false, unlike magnetic poles attract and
  like magnetic poles repel one another. TRUE
• Name one mechatronic device that you own or use
  on a regular basis- CD PLAYER, DISHWASHER
• Which engineering majors are some interest to
  you? Electrical, Computer Systems, Electric
  Power, Nuclear, Mechanical, Aeronautical,
  Biomedical, Civil, Industrial Management,
  Materials, Chemical, Environmental, Engineering
  Physics
• ELECTRICAL-THE ONLY ONE

49
Where Will You See This Material Again?

• Mechatronics MANE-4490 Mechatronics, MANE-4250
  Mechatronic Systems Design, MANE 6960 Sensors
  Actuators in Mechatronics
• Motor Drives ECSE/EPOW-4080 Semiconductor Power
  Electronics and EPOW-4090 Power Electronics Lab
• Motor Control ENGR-2350 Introduction to Embedded
  Control
• Concentration in Power Electronics EPOW-4080 and
  MANE-4490