Actuators (1)

© 2013 Stephen R. Platt ME 461 1

H-Bridge Motor Drivers

B A

C D

ON OFF

ON OFF

Forward

Actuators (1)

© 2013 Stephen R. Platt ME 461 2

H-Bridge Motor Drivers

B A

C D

OFF ON

OFF ON

Reverse

Actuators (1)

© 2013 Stephen R. Platt ME 461 3

H-Bridge Motor Drivers

B A

C D

OFF OFF

ON ON

Brake

Actuators (1)

© 2013 Stephen R. Platt ME 461 4

LMD18200 H-Bridge

Actuators (1)

© 2013 Stephen R. Platt ME 461 5

Actuators (1)

© 2013 Stephen R. Platt ME 461 6

PMDC Motors

stator

rotor brushes

commutator contacts

Actuators (1)

© 2013 Stephen R. Platt ME 461 7

PMDC Motors • Simple Model

in EdIV L RI Kdt

ω= + +

• More Complete Model

TK Iτ =Coulomb Friction

Viscous Friction

Actuators (1)

© 2013 Stephen R. Platt ME 461 8

PMDC Motors • More Complete Model

in EdIV L RI Kdt

ω= + +

( )T cK I J D D signυτ α ω ω= = + +

friction

Actuators (1)

© 2013 Stephen R. Platt ME 461 9

PMDC Motors • DC Motor Specifications

Actuators (1)

© 2013 Stephen R. Platt ME 461 10

Brushless DC Motors • Rotor with permanent magnets • Stator with windings • Essentially a DC motor turned inside out • Control electronics take the place of brushes and

commutators

Actuators (1)

© 2013 Stephen R. Platt ME 461 11

Brushless DC Motors

Actuators (1)

© 2013 Stephen R. Platt ME 461 12

Stepper Motors • Essentially a brushless DC motor with many more stator

and rotor poles.

Phase ‘a’ energized

Actuators (1)

© 2013 Stephen R. Platt ME 461 13

Stepper Motors • Full Step Motor

Phase ‘b’ energized

Actuators (1)

© 2013 Stephen R. Platt ME 461 14

Stepper Motors • Half Step Motor

Phase ‘a’ energized

Actuators (1)

© 2013 Stephen R. Platt ME 461 15

Stepper Motors • Half Step Motor

Phases ‘a’ and ‘b’ energized