Page 341 - The Mechatronics Handbook

TABLE 16.2 Type of Actuators and Their Features
Actuator Features
Electrical
Diodes, thyristor, bipolar transistor, triacs, diacs, power Electronic type
MOSFET, solid state relay, etc. Very high frequency response
Low power consumption

Electromechanical
DC motor Wound field Separately Speed can be controlled either by the voltage across the
excited armature winding or by varying the field current
Shunt Constant-speed application
Series High starting torque, high acceleration torque, high speed
with light load
Compound Low starting torque, good speed regulation
Instability at heavy loads
Permanent Conventional High efficiency, high peak power, and fast response
magnet PM motor
Moving-coil PM Higher efficiency and lower inductance than conventional
motor DC motor
Torque motor Designed to run for a long periods in a stalled or a low rpm
condition
Electronic commutation (brushless Fast response
motor) High efficiency, often exceeding 75%
Long life, high reliability, no maintenance needed
Low radio frequency interference and noise production
AC motor AC induction motor The most commonly used motor in industry
Simple, rugged, and inexpensive
AC synchronous motor Rotor rotates at synchronous speed
Very high efficiency over a wide range of speeds and loads
Need an additional system to start
Universal motor Can operate in DC or AC
Very high horsepower per pound ratio
Relatively short operating life
Stepper motor Hybrid Change electrical pulses into mechanical movement
Provide accurate positioning without feedback
Variable reluctance Low maintenance
Electromagnetic
Solenoid type devices Large force, short duration
Electromagnets, relay On/off control

Hydraulic and Pneumatic
Cylinder Suitable for liner movement
Hydraulic motor Gear type Wide speed range
Vane type High horsepower output
Piston type High degree of reliability
Air motor Rotary type No electric shock hazard
Reciprocating Low maintenance
Valves Directional control valves
Pressure control valves
Process control valves

Smart Material actuators
Piezoelectric & High frequency with small motion
Electrostrictive High voltage with low current excitation
High resolution
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