Page 111 - Toucpad robotics C11

Types of DC Motors:
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∑ Brushed DC Motors: These are the most basic and common type, using physical brushes and a commutator. They
are simple and inexpensive.
∑ Brushless DC (BLDC) Motors: These motors eliminate the brushes and commutator, using electronic commutation
instead. This leads to higher efficiency, longer lifespan, less noise, and lower maintenance. However, they require
a more complex electronic controller.
∑ Geared DC Motors: Often, a gearbox is attached to a DC motor to reduce its output speed while significantly
increasing its torque. This is very common in robotics where high torque is often needed at lower, more
controllable speeds.

Applications in Robotics

u Robot Locomotion: Driving wheels or tracks in mobile robots (e.g., robotic vacuum cleaners, simple wheeled robots,
educational robots).
Simple Joints: Used in robot arms or grippers where precise position control is not the absolute priority, but continuous
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motion or strong torque is needed.
Fans and Pumps: In auxiliary systems within larger robotic platforms.
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Conveyor Systems: In automated manufacturing lines.
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Advantages
Cost-Effective: Generally, less expensive, especially brushed DC motors.
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Simple Control: Relatively easy to control speed (with PWM) and direction (by reversing polarity).
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High Starting Torque: Good for applications requiring strong initial push or pull.
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Compact Size: Can be quite small, suitable for many robotic applications.
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u Quick Response: Can start, stop, and reverse direction relatively quickly.
Disadvantages
Brush Wear (for Brushed DC Motors): Brushes wear out over time due to friction, requiring maintenance and
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replacement. This also generates electrical noise and sparks.

u Limited Precision (without feedback): Without an external sensor (like an encoder) providing feedback on their
exact rotational position, simple DC motors provide “open-loop” control, meaning their exact position isn’t known,
which can lead to positioning errors.
Less Efficient (Brushed): Brushed motors can lose energy due to friction and heat from the brushes.
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Noise (Brushed): Can generate audible noise and electromagnetic interference due to sparking at the brushes.
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Complexity (BLDC): While better performing, BLDC motors require more complex and expensive electronic
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controllers.

Robots in Disaster Zones Save Lives

Search-and-rescue robots are becoming crucial in natural disasters like earthquakes or
floods. They can enter collapsed buildings, locate survivors using sensors, and even deliver
BRAINY supplies. Drones powered by AI can scan huge areas quickly, identifying where humans are
FACT
trapped. In Japan, snake-like robots are being designed to crawl through tiny spaces to detect
survivors. These life-saving robots show that technology isn’t just about convenience—it can
be the difference between life and death.

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Electrical and Control Systems