Transcript Diapositiva 1

MECATRONICA 1.
Sem. 1-2007
Universidad EAFIT Profesores: Hans Ley (Dipl.-Ing.) y
Alejandro Velásquez (MSc.Mechatronics)
1
1. OVERVIEW
1.1. Origin:
 The word mechatronics was first coined by a Japanese company;
Yaskawa, in 1969, as a combination of "mecha" of mechanisms and
"tronics" of electronics and the company was granted the trademark rights
on the word in 1971.The word soon received broad acceptance in industry
and, in order to allow its free use, Yaskawa elected to abandon its rights
on the word in 1982.
 For this wider concept of mechatronics, a number of definitions has been
proposed in the literature, differing in the particular characteristics that the
definition is intended to emphasize. The most commonly used one
emphasizes synergy:
“Mechatronics is the synergistic integration of
mechanical engineering with electronics and intelligent
computer control in the design and manufacture of
products and processes.”
Sem. 1-2007
Universidad EAFIT Profesores: Hans Ley (Dipl.-Ing.) y
Alejandro Velásquez (MSc.Mechatronics)
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1.2. Other definitions:
Ohio State University in Columbus:
“The confluence of traditional design methods with sensors and
instrumentation technology, drive and actuator technology, embedded
real-time microprocessor systems, and real-time software."
University of Applied Sciences Weingarten – Ravensburg:
“Mechatronics is an interdisciplinary, system oriented discipline,
comprising developing technical solutions at the interface of mechanical
engineering, electrical engineering and computer science. It deals with
the increasing integration of mechanical systems with digital electronic
systems and information technology.”
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1.3. Importance:
 With a focus on these kinds of skills, mechatronics is seen as a prime career
path for mechanical engineers of the future. "I believe that mechanical
engineers with a mechatronics background will have a better chance of
becoming managers," said Thomas S. Moore, general manager for liberty
and technical affairs at Chrysler Corp. in Madison Heights, Mich. "We see
mechatronics as the career of the future for mechanical engineers."
 The view of Belgian robotics researcher Hendrik M. J. Van Brussel, published
in Transactions (June 1996), follows a similar fundamental theme but with a
different emphasis. "In the past, machine and product design has, almost
exclusively, been the preoccupation of mechanical engineers," he wrote.
Solutions to control and programming problems were added by control and
software engineers, after the machine had been designed by mechanical
engineers. This sequential-engineering approach usually resulted in
suboptimal designs.
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 "Classically trained mechanical engineers will run the risk of being
left out of the interesting work" carried on by multidisciplinary product
design teams, according to John F. Elter, vice president of strategic
programs at Xerox Corp. in Webster, N.Y. "At Xerox, we need designers
who understand the control theory well enough to synthesize a better
design. These people will have much more of a chance to lead."
Elter added that "the mechanical engineers who know some
computer science are far more valuable than the computer
scientists who know some mechanical engineering. The mechanical
engineers have a better feeling for the overall system and do a better job
of making the crucial trade-offs. One possibility is that the mechatronics
practitioner will prototype the whole design, then the specialists in the
various disciplines will take over the detail design."
Taken from
Sem. 1-2007
http://www.memagazine.org/backissues/may97/features/mechtron/mechtron.html
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1.4. Integration:
•Kinetics
System
•Statics
Modelling
•Materials
•Mechanisms
•Neumatics
•Hydraulics
•Actuators
•Relays
•Motors
Actuators
Sensors
•SolidWorks
•Autodesk Inventor
•Mechanical Desktop
•ANSYS
•C
•Visual Basic
•Algorithms
Sem. 1-2007
•Signal processing
•Sensors
•Circuits
•Op Amps
•Timer
Simulation
Microcontrollers
LabView
Matlab
Universidad EAFIT Profesores: Hans Ley
(Dipl.-Ing.) y Alejandro Velásquez
(MSc.Mechatronics)
•Feedback
•Cascade Control
•Adaptive Control
•Modelling
•1st Order Systems
•2nd Order Systems
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1.5. Examples
Light-Weight-Robot
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Artificial Heart
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1.5. Examples
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Tasks for this semsester
 Construction of a model of an assembly plant
- mechanical construction
- selection of the sensors and the actuators
- selection of the control system (PLC, µ -controller, LabView, …..)
 Basics of electronics and informatics
 Theory of invention (Triz)
 Using a communication platform (Wiki)
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Automatic Bull´s Eye
Dancing Robots
Keyboard Testing Device
Motion Control
Videos taken at Automatica Fair. Munich, Germany. May 2006.
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2. AC/DC POWER SUPPLY
2.1. Why do we have AC?
AC is the preferred method of delivering electricity because devices can be
used to break the voltage down into smaller pieces. Because there is no
variation, there is no way to break the voltage into smaller pieces.
A transformer can be used to break 220v AC down to 110v AC. High
voltage lines can be used to deliver 15,000v to a neighborhood and local
transformers will break the electricity down for the homes.
DC doesn't have the cycle variation, a 220v DC flow is always +220v.
2.2. Properties of AC?
2.2.1 Amplitude
This is just how positive or negative the voltage is, with respect to some
selected neutral reference. With DC the voltage is constant at some
measurable value. But AC is constantly changing.
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Mathematically, the amplitude of a sine wave is the value of that sine
wave at its peak. This is the maximum value, positive or negative, that it
can attain. However, when we speak of an AC power system, it is more
useful to refer to use the effective voltage or current. This is the rating
that would cause the same amount of work to be done (the same effect)
as the same value of DC voltage or current would cause.
That's why rms (or effective) values are useful: they give us a way to
compare ac voltages to dc voltages
Effective Voltage: = RMS (Root Mean Square) Voltage: Effective
Voltage is equal to the square root of the mean value of the squares of all
the instantaneous values of an AC voltage
Average Voltage: Although the average of a bounded sinusoidal function is
zero, the "effective" value is not zero. For example, electric hot water
heaters work very well on sinusoidal voltages, with zero average values.
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2.2.2 Sinusoidal Signals
Veff 
V
2
110VAC is actually the RMS value which is usefull for the energy
company. But the voltage peak value is 155.55V.
Measuring Tip:
When used to measure ac voltages or currents, the multimeter gives you
something called the effective value, or rms value.
While using the oscilloscope, it gives the peak to peak value.
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 Formula demonstration of the VRMS for Sinusoidal signals
Eeff  Esin
Veff2
T
1
2
 T    V (t )   dt
R
R 0
1
2
   V peak  Sin(2    f  t )   dt
T 0
T
Veff2
Veff2 
2
eff
V

T
2
V peak
2 T
T
  Sin2 2    f  t   dt
0
Veff2 
T
  1  Cos4    f  t   dt
0
Veff 
2 T
2
V peak
Sem. 1-2007
V
 T  0  0  0
2
V peak

Sin4    f  T  
 T  0 
 0
2 T 
4   f

2
V peak

Sin4   1 

 T  0 
 0
2 T 
4   f

Veff2 
Veff2
2
V peak
Veff2 
2
V peak
2
peak
Universidad EAFIT Profesores: Hans Ley (Dipl.-Ing.) y
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2.3. Why do we need an AC/DC Power Supply?
Because the two major families of logic devices, which are TTL and
CMOS, work under DC voltages. Typically 5V and 12V.
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Alejandro Velásquez (MSc.Mechatronics)
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Sem. 1-2007
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Other types of DC power sources for CMOS devices.
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2.4. FIRST PROJECT – AC/DC POWER SUPPLY
2.4.1. Block Diagram:
110
AC
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2.4.2. Common Circuit Diagram:
Note: This configuration applies for 230V (Europe).
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2.4.3. Transformer:
 Function: A transformer is a device used to increase (step up) or decrease
(step down) the AC voltage in a circuit.
 Properties: Laminated in order to reduce power losses through Eddy
Currents.
 Operation: The way transformers operate is based on the principle that an
alternating current in the primary coil will induce an alternating emf on the
secondary coil due to their mutual inductance.
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2.4.3.1. What is happening inside a transformer?
2. Energizing the coil and
thus magnetic flux
generation.
1. Iron Core molecules
before energizing.
3. Iron Core molecules line
up after energizing.
2.4.3.2. And by mathematical means...
The magnetic flux is time-variable at a stationary surface (The cross sectional
Area of the iron core).
Eqn 1.
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Eqn. 2
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Eqn 1 & Eqn 2  Eqn 3
Eqn 4.
Eqn 3 & Eqn 4  Eqn 5
Q1. IS IT POSSIBLE TO TRANSFORM DC CURRENT INTO A LOWER VALUE DC BY
USING A TRANSFORMER?
Q2. WHAT IS THE MEANING OF MUTUAL INDUCTANCE?
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2.4.4. Rectifier:
2.4.4.1.Diode
Ideal Diode
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Real Diode
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2.4.1.2. Half Wave Rectifier:
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2.4.1.3. Full Wave Rectifier:
Link to PDF with the bridge rectifier
animation
 One disadvantage of the full-wave rectifier is that there is a voltage
loss of 1.4V across the diodes.
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Universidad EAFIT Profesores: Hans Ley (Dipl.-Ing.) y
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You could either build a full wave rectifier bridge out of 4 diodes (i.e. 1N4001
capable of 50V and 1A) or an already made rectifier as the one shown below:
While the full-wave rectifier is an improvement on the half-wave rectifier, its
output still isn't suitable as a power supply for most circuits since the output
voltage still varies between 0V and Vs-1.4V. So, if you input 12V AC, you
will get 10.6V DC output.
This is why the 'smoothing' block, described in the next chapter is required.
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2.4.5. Smoothing:
Vr
I
Vr 
2C. f
 Where: I [Amps], C [F], f [Hz]
and Vr [V]
 Note: The ripple voltage shouldn't
be higher than 10% of Vs.
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Universidad EAFIT Profesores: Hans Ley (Dipl.-Ing.) y
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Ex 1: What should be the Capacitance to appropriately smooth an 24Vpp AC
signal, 60Hz and 1A?
I
1A
C

 6950F
2  Vr  f 2  0,112V 60Hz
Ex 2: How big would the Ripple voltage be if the current gets reduced to
500mA?
I
0,5 A
Vr 

 0.6V
3
2  C  f 2  6,95e  60Hz
Compromise:
• Availability of components
• Price of components
• Ripple voltage
Q3: What factors affect the amount of ripple?
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2.4.6. Regulation:
 Reason: While there are many circuits that will tolerate a smoothed power
supply, some must have a completely regular supply with no ripple voltage.
If the ripple voltage is too large and the input voltage to the regulator falls
below the regulated voltage of the regulator, then of course the regulator will
not be able to produce the correct regulated voltage.
As a rule of thumb the input voltage to a regulator should usually be at least
2V above the regulated voltage.
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By using the brochures of the components all the requirements can be found.
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END
Sem. 1-2007
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Alejandro Velásquez (MSc.Mechatronics)
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