Introduction Chapter 1

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Introduction(Chapter 1)
BEE3163 ELECTROMECHANICAL SYSTEMS
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Mechatronics and Emerging Trends in Engineering

• Mechatronics is a system-level approach to
  designing electromechanical systems that merges
  mechanical, electrical, control system, and
  embedded software design.
• It represents an industry-wide effort to improve
  the design process by integrating the best
  available development practices and technologies
  to streamline design, prototyping, and
  deployment.

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• Why Study Mechatronics
• If you design industrial machinery, equipment,
  vehicles, or other devices with moving parts and
  electronically controlled actuators, mechatronics
  technology may help you lower development costs,
  reduce risk, and produce higher-quality
  products.Benefits of Mechatronics
• Higher profitability through faster, lower-risk,
  lower-cost development
• Increased efficiency due to better communication,
  collaboration, and integration
• Greater innovation through increased design
  automation across engineering domains

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Mechatronics and Emerging Trends in Engineering

• Electromechanical System Integrate
  electromechanical motion devices (actuator and
  sensors), transducers (analog and digital), power
  electronics and converters, controllers (analog
  and digital), data equisition system and etc

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Mechatronics and Emerging Trends in Engineering

• Electromechanical motion devices studied using
  electromagnetics and mechanics
• Electromechanical energy conversion devices
  convert electrical energy to mechanical energy
  and mechanical energy to electrical energy
• Actuator control by power converters (eg to
  regulate the angular velocity of electric motor)
  and control algorithm should be designed to
  control electromechanical systems
• Transducer is a device, usually electrical,
  electronic, electro-mechanical, electromagnetic,
  photonic, or photovoltaic that converts one type
  of energy to another for various purposes
  including measurement or information transfer
  (for example, pressure sensors)
• These control laws implemented using analog and
  digital controllers, and PC DSP hardware and
  microcontrollers

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Mechatronics and Emerging Trends in Engineering

• Mechatronics is a multi-disiplinary concepts,
  integrates electrical, mechanical, and software
  engineering
• Example mechatronics concept motion control
  problem in aircraft. The aircraft is controlled
  by flight control surface
• Direct drive servo system are used to actuate
  these control surface
• This system fly-by-wire flight servo system
  actuated by stepper motor

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Fly-by-wire

• Mechanical and hydraulic flight control systems
  are heavy and require careful routing of flight
  control cables through the aircraft using systems
  of pulley, cranks, wires and, with
  hydraulically-assisted controls, hydraulic pipes.
  
• Both systems often require redundant backup,
  which further increases weight

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Fly-by-Wire

• The words Fly-by-Wire imply only an
  electrically-signalled control system.
• The term is generally used, however, in the sense
  of computer-configured controls.
• This is where, between the operator and the final
  control actuator or surface, a computer system is
  interposed.
• This modifies the inputs of the pilot (or
  operator for non-aircraft systems) in accordance
  with software programmes.
• Mechatronics and Emerging Trends in Engineering

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Mechanical

• The flight control systems uses a collection of
  mechanical parts such as rods, cables, pulleys
  and sometimes chains to transmit the forces of
  the cockpit controls to the control surfaces.
• Since an increase in control surface area in
  bigger and faster aircraft leads to a large
  increase in the forces needed to move them,
  complicated mechanical arrangements are used to
  extract maximum mechanical advantage in order to
  make the forces required bearable to the pilots.

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Hydraulic

• A hydraulic flight control systems has 2 parts
• The mechanical circuit
• The mechanical circuit links the cockpit controls
  with the hydraulic circuits. Like the mechanical
  flight control systems, it is made of rods,
  cables, pulleys, and sometimes chains.
• The hydraulic circuit
• The hydraulic circuit has hydraulic pumps, pipes,
  valves and actuators.
• The actuators are powered by the hydraulic
  pressure generated by the pumps in the hydraulic
  circuit.
• The actuators convert hydraulic pressure into
  control surface movements. The servo valves
  control the movement of the actuators.

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Mechatronics and Emerging Trends in Engineering

• Mechtronics concept is applied to approach and
  solve dynamics and control problems. Example
  high level closed loop flight control system,
  robotics system
• Mechatronics emerges as a most general concept
  that provide a systematic and unified conceptual
  framework in analysis and optimization,
  prototyping and design, and control and
  deployment of a system

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Mechatronics and Emerging Trends in Engineering

• Modern electromehanical system rely increasingly
  on digital controllers (microprocessor and DSP)
• Block diagram of typical digitally controlled
  system
• The design specification imosed on
  electromechanical system are given in the system
  domain. The commonly used performance criteria to
  be attained are
• Stability with the desired stability margins in
  the full operating envelope
• Robustness to parameters variations and
  structural changes
• Tracking and disturbance attenuation
• Dynamic and steady state accuracy
• Specification imposed on the states and outputs
  transient response

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Unit step response of a 2nd order underdamped
system
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BASIC FOUNDATION

• Electromechanical system must be studied using
  the fundamental laws and basic principles of
  mechanics and electromagnetics
• Mechanics
• Is the study of the motion of systems with the
  corresponding analysis of forces that cause
  motion is of interest
• Newtons second law of motion states that the net
  vector acting on an object of mass m is related
  to its acceleration vector

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BASIC FOUNDATION

• In the Cartesian (XYZ) coordinate system
• represent the magnitude and direction of
  the net force acting on the object. is
  not a force
• A body at equilibrium that is the object is at
  rest or moving with constant speed

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BASIC FOUNDATION

• Newtons second law of motion in terms of linear
  which is found as

For rotational motion, the net torque and angular
acceleration must be used. The torque vector
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BASIC FOUNDATION

• The rotational analog of Newtons second law for
  a rigid body

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BASIC FOUNDATION

• The angular momentum of the system is expressed by

For the rigid body rotating around the axis of
symmetry
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BASIC FOUNDATION

• Example 1
• An electric motor has the equivalent moment of
  inertia J0.06kgm2. The motor starts from the
  stall and the angular velocity of the motor is
• Find the angular momentum and the developed
  electromagnetic torque as function of time. The
  load and friction torque are zero.

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BASIC FOUNDATION

• From newtonian mechanics the applied net force
  plays a central role in quantitatively describing
  the motion.
• Total energy of the system

For translational motion of a body to an ideal
spring
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BASIC FOUNDATION
For rotational spring
Kinetic energy of translation and rotation
The moment of inertia is depends on how the mass
is distributed with respect to the axis, and J is
different for different axes of rotation
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BASIC FOUNDATION
Assuming the body is rigid, and the moment of
inertia, J is constant
The total work is given by
The change if the kinetic energy
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BASIC FOUNDATION
Power is defined by
In analog which is applied for translational
motion, Power
Example 1.6 An electric motor drives a load
and the electromagnetic torque developed by the
motor is 0.2 N.m (Te0.2N.m). The motor starts
from stall and has the equivalent moment of
inertia 0.01 kg.m2 (J 0.01 kg.m2 ). Calculate
the work and kinetic energy at t15s