Electric Motors and Motion Control

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Electric Motors and Motion Control

• Ara Knaian

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Motors

• Motors convert electrical energy to mechanical
  energy
• Motors make things move

LINEAR
DC BRUSH
INDUCTION
ELECTROSTATIC
STEPPER
UNIVERSAL
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How a DC Motor Works
Brushes
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How a DC Motor Works
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Motor Modeling

• Is this motor big enough?
• Will this thing move?
• What gear ratio should I use?
• How big should my power supply be?
• How hot will it get?
• How fast can I machine?
• What materials can I machine?

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Motor Modeling
Voltage and Current In
Torque and Speed Out
Heat Out
Power In Power Out
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Motor Modeling
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Motor Modeling
Torque is proportional to current In an ideal
motor (R 0), speed is proportional to
voltage At constant voltage, speed goes down as
torque goes up
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Pittman Motor Data Sheet
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Pittman Motor Data Sheet
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Bidirectional Motor Drive H-Bridge
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Speed Control PWM
Like Low Voltage (slow)
Like High Voltage (fast)
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Rotary Shaft Encoder
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Motor Control Linear Servo Loop
Mechanical System
Motor
Encoder
Controller
Set Point (desired position, velocity)
Measured Output (position/velocity)
e.g. PID
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Practical Motor Controller Block Diagram
Mechanical System
Motor
Encoder
H Bridge
Limit Switch
Microcontroller