Which Motors are used in Robotics?

A motor is an indispensable part of any robot. It’s responsible for the majority of the physical movement and functionality. There are different types of motors used in robotics, including DC motors, servo motors, and stepper motors, each having unique features that make them suitable for various applications.

This article will delve into the critical role of motors in robotics, examining the types of motors commonly used, how they function, and how they’re applied in different types of robots.

Table of Contents

1. The Role of Motors in Robotics
2. Types of Motors used in Robotics
   • DC Motors
   • Servo Motors
   • Stepper Motors
3. Why AC Motors are not used in Robotics?
4. Most common brands for motors in Robotics
   • 1. DC Motors
   • 2. Servo Motors
   • 3. Stepper Motors
5. Conclusion

The Role of Motors in Robotics

Motors convert electrical energy into mechanical energy thanks to electromagnetic principles, thereby powering the physical movements of a robot. The robot’s controller dictates these movements, sending signals to the motor to execute certain actions. The robot’s movements could range from something as simple as rotating wheels to something more intricate like performing a surgical operation.

The motor forms a key part of a robot’s actuator system, which is responsible for moving and controlling the robot’s mechanisms. It also determines a robot’s precision, speed, torque, and other important attributes of performance.

Types of Motors used in Robotics

DC Motors

Direct Current (DC) motors are the most common type of motors used in robotics. They are simple to use and control, provide a good speed range, and offer a high torque for their size. There are two types: brushed and brushless DC motors.

• Brushed DC Motors: These motors consist of a rotating armature, fixed stator, and a commutator. The brush makes physical contact with the commutator, making these motors relatively easy to control. However, their brushes wear out over time and require replacement, leading to higher maintenance.
  Here you can find this type of motors on amazon.
• Brushless DC Motors: These motors are designed to overcome the maintenance issue associated with brushed DC motors. Instead of brushes, they use a controller to change the direction of the current. Brushless DC motors are efficient, reliable, and last longer than their brushed counterparts, but they are more expensive and complex to control.
  Here you can find this type of motors on amazon.

Servo Motors

Servo motors consist of a DC motor, gearbox, potentiometer, and control circuit. They’re known for their precision and control. A servo motor’s position can be controlled very accurately using Pulse Width Modulation (PWM) signals, making them ideal for applications that require precise movement control.

Stepper Motors

Stepper motors work differently than DC and servo motors. They move in discrete steps, offering excellent control of position and speed. Stepper motors are digitally controlled and have high torque at low speeds, making them perfect for applications where you need to hold a load at a specific position for a long time.

Why AC Motors are not used in Robotics?

AC (Alternating Current) motors are indeed used in some applications in robotics, but they’re not as commonly used as DC (Direct Current) motors. This is primarily due to several reasons:

1. Control Simplicity: DC motors are simpler to control. They provide a constant, steady current that makes it easy to manage speed, torque, and direction. In contrast, AC motors rely on the frequency of the AC supply to control these factors, making them more complex to manage in terms of speed and torque.
2. Power Supply: Most robotic systems use batteries as their primary power source, which deliver DC power. Converting DC to AC would require additional components, increasing complexity and potentially reducing efficiency.
3. Size and Weight: DC motors, particularly brushless ones, can deliver a high torque-to-weight ratio, making them more suitable for mobile robotic applications where minimizing weight is crucial. AC motors, especially induction motors, are often heavier for the same power output.
4. Precision Control: Servo and stepper motors, which are fundamentally DC devices, offer superior control over position, speed, and acceleration, making them ideal for applications that require precision.

Despite these points, AC motors are used in some industrial robots for specific tasks that require high power and high speed, rather than precision. For instance, an AC induction motor might be used to drive a conveyor belt in an automated factory line. Furthermore, some advanced control systems do make use of AC servo motors, leveraging the advantages of AC power for high-performance applications.

The use of AC versus DC motors ultimately depends on the specific requirements of the robotic application, considering factors such as power source, precision requirements, size, weight, and cost.

Most common brands for motors in Robotics

When it comes to choosing motors for robotics applications, several well-known brands stand out, offering a range of motors with varying characteristics. Here are some prominent manufacturers of the most commonly used motors in robotics:

1. DC Motors

• Maxon Motor: Maxon Motor is a Swiss manufacturer renowned for producing high-quality DC motors, particularly brushless DC motors. They are often used in high-end applications, like space exploration robots, where reliability is critical.
• Faulhaber: Faulhaber offers a wide range of brushed and brushless DC motors known for their high precision, efficiency, and reliability. They are frequently used in medical devices and precision industrial equipment.
• Pololu: Pololu provides a range of DC motors suited to small robotics projects, including hobby and educational robots. They are popular due to their affordability and versatility.

2. Servo Motors

• Hitec: Hitec is a popular brand in the world of hobbyist robotics. Their servo motors are known for their quality and affordability.
• Futaba: Futaba is another popular brand among hobbyists and professionals alike. They offer a wide variety of servo motors, suitable for a range of applications from small-scale models to larger industrial projects.
• KUKA: KUKA is well-known for their industrial robots and uses high-quality AC and DC servo motors in their robotic arms.

3. Stepper Motors

• NEMA (National Electrical Manufacturers Association): NEMA doesn’t manufacture stepper motors themselves, but they set the standards that stepper motors are classified by. NEMA 17 and NEMA 23 are the most common sizes of stepper motors used in robotics.
• Oriental Motor: This company offers a wide range of stepper motors, including those with integrated drivers or controllers.
• Lin Engineering: Known for manufacturing high-performance stepper motors that are commonly used in precision applications.

While this is by no means an exhaustive list, these are some of the major brands that provide reliable, high-quality motors suitable for a variety of robotics applications. When choosing a motor for a robotic application, it is vital to consider not only the type and brand of the motor, but also other factors such as power, speed, torque, precision, efficiency, and the specific requirements of the robot. In this article we’ll be discussing about that.

Conclusion

Motors play an essential role in robotics, enabling the transformation of electrical energy into mechanical movement. The type of motor used significantly influences a robot’s capabilities, but remember that it is even more important to choose a motor that satisfies technical requirements such as power, speed torque… we’ll discuss about this in the next post.