Robotics deals with the design, construction, operation, and use of robots, as well as computer systems for their control, sensory feedback, and information processing. These technologies are used to develop machines that can substitute for humans and replicate human actions

1. ROBOTICS
ANd
AUTOMATION
ELECTRIC DRIVE
SYSTEMS
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2. OVERVIEW
• Electric drive system
• DC motor
• Servo motor
• Stepper motor
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3. WHAT IS ELECTRIC DRIVE SYSTEM?
• The electrical drive system is defined as the system
which is use for controlling the speed, torque and
direction of an electrical motor. Each electrical drive
system is different from other electrical drive
systems, but there are some common features
associated with all electrical drive systems.
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4. COMPONENTS
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5. INCOMING AC SWITCHGEAR(SOURCE)
• It consists a switch fuse unit and AC power contractor which
have ranges up to 660V, 800A.The switch gear replaces the
normal contractor by the bar mounted contractor and also
used air circuit breaker as an incoming switch.The bar
mounted contractor increase the range up to 1000V, 1200A.
• It uses the HRC fuse whose rating is up to 660V, 800A. The AC
switchgear consists thermal overload for protecting the
system from overloading. Sometimes the contractor of the
switchgear is replaced by the moulded case circuit breaker.
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6. POWER CONVERTER/MODULATOR
• This assembly has two major blocks – power and control
electronics. The power electronics blocks consist of
semiconductor devices, heat sinks, semiconductor fuses,
surge suppressors, cooling fans.
• Control electronics consist of triggering circuit, its own
regulated power supply and driving and the isolation circuit.
The driving and isolation circuit controls and regulates the
power flow to the motor.
• When the drive operates in a closed loop, it will have a
controller and current and speed feedback loops. The control
system has three port isolation, i.e. the power supply, inputs
and outputs which are isolated with adequate insulation
levels.
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7. SENSING UNIT
• It protects the semiconductor converter against voltage
spikes produce in the line due to on and off switchings of
the load connecting on the same line. The line surge
suppressor along with the inductance suppress the
voltage spikes.
• The line surge suppressor absorbs a certain amount of
trapped energy when the incoming circuit breaker
operates and breaks the current supplied to the trap. The
line surge suppressor will not be required when the
power modulator is not a semiconductor.
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8. CONTROL UNIT
• It is used for interlocking and sequencing of various
operations of the drive system under normal, fault and
emergency condition. The interlocking protects the system
against abnormal and unsafe operations. The sequencing
protects the various drive operations, such as starting,
braking, reversing, jogging, etc., which are carried out in a
pre-planned sequence. For complex interlocking and
sequence operations, the programmable logic controller is
used.
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9. ADVANTAGES
• Large range of torque, speed and power.
• Their working is independent of the environmental
condition.
• The electric drives operate on all the quadrants of
speed torque plane.
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10. APPLICATIONS
• Transportation systems
• Rolling mills
• Paper machines
• Textile mills
• Machine tools
• Fans
• Pumps
• Robots
• washing, etc.
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11. DC MOTORS
• DC motors were the first form of motor.
• They could be powered from existing direct-current lighting power
distribution systems.
• A DC motor converts direct current electrical energy into
mechanical energy.
• A DC motor's speed can be controlled using a variable supply
voltage or by changing the strength of current in its field windings.
• All types of DC motors have some internal mechanism, to change
the direction of current flow in part of the motor.
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12. TYPES OF DC MOTORS
1. Permanent magnet DC motor
2. Series DC motor
3. Shunt DC motor
4. Compound DC motor
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13. 1. PERMANENT MAGNET DC MOTOR
• The permanent magnet motor uses a permanent magnet
to create field flux.
• This type of DC motor provides great starting torque and
has good speed regulation.
• But torque is limited so they are typically found on low
horsepower applications.
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14. 2. SERIES DC MOTOR
• Series DC motors create a large amount of starting torque, but
cannot regulate speed and can even be damaged by running
with no load.
• These limitations mean that they are not a good option for
variable speed drive applications.
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15. 3. SHUNT DC MOTORS
• In shunt DC motors the field is connected in parallel
(shunt) with the armature windings.
• These motors offer great speed regulation due to
the shunt field can be excited separately from the
armature windings.
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16. 4. COMPOUND DC MOTOR
• Compound DC motors, like shunt DC motors, have a
separately excited shunt field.
• Compound DC motors have good starting torque but
may experience control problems in variable speed
drive applications.
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17. APPLICATIONS
SI.NO DC MOTORS APPLICATIONS
1 Permanent magnet DC motor Computer drives, toy
industries.
2 Series Dc motor Conveyors, cranes,
Elevators.
3 Shunt DC motor Machine tools, drilling
machine.
4 Compound DC motor Elevators, rolling mills.
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18. DC MOTOR DRIVE
• The DC motor drive is a type of amplifier or power modulator
that integrate between the controller and a DC motor.
• It takes the low current and then converts it into a high
current which is appropriate for the motor.
• The DC motor drive also provides the high current torque, 400
% more than the rated continuous torque.
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19. TYPES OF DC MOTOR DRIVE
1. Non-regenerative DC motor Drive
• This drive rotates only in one direction and hence also called
single quadrant drive.
• The non-regenerative DC motor drive does not have any
inherent braking capability.
• The motor is terminated only by removing the supply
• Such type of drive is used in a placed where high friction load
or strong natural brake requires.
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20. Contd...
2. Regenerative DC motor Drive
• It is a four quadrant drive, and it controls the speed,
direction and torque of a motor.
• Under the braking condition, this drive converts mechanical
energy and load into electrical energy which is returned to
the power source.
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21. APPLICATIONS OF DC MOTOR DRIVE
1. Printing presses
2. Elevators
3. Textile mills
4. Paper mills
5. Rolling mills
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22. SERVO MOTOR
• Servo Motor are also called Control motors. They are used
in feedback control systems as output actuators and does
not use for continuous energy conversion.
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23. WORKING PRINCIPLE
• The Servo Motor basically consists of a DC Motor, a Gear
system, a position sensor and a control circuit.
• The DC motors get powered from a battery and run at high
speed and low torque. The Gear and shaft assembly lower this
speed into sufficient speed and higher torque.
• the signals from the position sensor and compares the actual
position with the desired position and accordingly controls
the direction of rotation of the DC motor to get the required
position.
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24. SERVO DRIVE
• A servo drive is a special electronic amplifier used to power
electric servomechanisms.
• A servo drive monitors the feedback signal from the
servomechanism and continually adjusts for deviation
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25. FUNCTIONS
• A servo drive receives a command signal from a control
system, amplifies the signal, and transmits electric current to
a servo motor.
• A sensor attached to the servo motor reports the motor's
actual status back to the servo drive.
• The servo drive then compares the actual motor status with
the commanded motor status. It then alters the voltage,
frequency or pulse width to the motor .
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26. CHARACTERISTICS OF SERVO MOTOR
DC servo motor AC servo motor
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27. ADVANTAGES AND DISADVANTAGES
ADVANTAGES:
• If a heavy load is placed on the motor, the driver will increase the
current to the motor coil as it attempts to rotate the motor. Basically,
there is no out-of-step condition.
• High-speed operation is possible.
DISADVANTAGES:
• Since the servomotor tries to rotate according to the command pulses,
but lags behind, it is not suitable for precision control of rotation.
• Higher cost.
• When stopped, the motor’s rotor continues to move back and forth
one pulse, so that it is not suitable if you need to prevent vibration
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28. APPLICATIONS
• In Industries they are used in machine tools, packaging, factory
automation, material handling, printing converting, assembly
lines.
• They are also used in radio controlled airplanes to control the
positioning and movement of elevators.
• They are used in robots because of their smooth switching on and
off and accurate positioning.
• They are also used by aerospace industry to maintain hydraulic
fluid in their hydraulic systems.
• They are used in many radio controlled toys.
• They are also being used in automobiles to maintain the speed of
vehicles.
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29. STEPPER MOTOR
A stepper drive is the driver circuit that controls how
the stepper motor operates. Stepper drives work by
sending current through various phases in pulses to the
stepper motor.
There are four types:
• wave drives (also called one-phase-on drives)
• two-phase on drives
• one-two phase-on drives
• Micro stepping drives.
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30. WAVE DRIVES
• Wave or one-phase-on drives work
with only one phase turned on at a
time. Consider the illustration below.
• it is inefficient and provides little
torque, because only one phase of
the motor engages at a time.
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31. TWO-PHASE ON DRIVES
• Two-phase-on driving has its
name because two phases are
on at a time
• Two-phase-on driving gets no
finer resolution than one-
phase on, but it does produce
more torque
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32. ONE-TWO PHASE-ON DRIVES
• One-two phase-on driving has its
name for the way the drive energizes
either 1 or 2 phases at any specific
time.
• One-two phase-on driving delivers
finer motion resolutions. When two
phases are on, the motor produces
more torque.
• One caveat here: torque ripple is a
concern because it may cause
resonance and vibration.
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33. MICRO STEPPING DRIVES.
• Micro stepping delivers very fine motion resolutions. Here,
the drive uses current regulation to prevent torque
oscillations.
• In sort, a drive that is micro stepping increases and decreases
current along a sine wave, so no pole is fully on or off
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