Tony Yi 5/2/2015 CENG4480 TUTORIAL 3. ABOUT ME I am “the other” tutor of CENG4480 You can find me at Rm116 in SHB Email : [email protected].

Tony Yi

5/2/2015

CENG4480 TUTORIAL 3

ABOUT ME

• I am “the other” tutor of CENG4480

• You can find me at Rm116 in SHB

• Email : [email protected]

THE FULL PICTURE

Environment

Sensor

Input

Control System

Actuator

Output

We focus on this part.

ACTUATOR

• To convert the digital signals into mechanic motion

• Motor (mainly), heater, buzzer, LED, LCD

Internal Signal Actuator Feedback

ACTUATOR

• Introduce Pulse-Width-Modulation (PWM)

• Focus on servo motor

Internal Signal Actuator Feedback

PULSE WIDTH MODULATION (PWM)

• Pulse-width-modulation (PWM) is a fancy term for describing a type of digital signal

• Changing ‘HIGH’ time of the output signal

HIGH

LOWLOW

“HIGH” time

PULSE WIDTH MODULATION (PWM)

• Duty cycle On Time

Off Time

* 100%

PULSE WIDTH MODULATION (PWM)

• Example

• https://www.youtube.com/watch?v=X1ZmNHg0G30

SERVO MOTOR

• A servomotor is a rotary actuator that allows for precise control of angular position, velocity and acceleration.

SERVO MOTOR

• Small device that has an output shaft

• Angular position of that shaft controlled by the input signal (typically PWM) Shaft

Body

Input Signal

SERVO MOTOR

• A servo motor itself is a close loop control system.

Gear

Control Circuit

Position Sensor(connected to shaft)

DC Motor

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