Selection of Right Robotic Motor

How to choose a right Robotic Motor

Robots are mechanical devices that can execute certain physical tasks and have software-based intelligence. Robots and robotic applications come in a variety of shapes and sizes. The robots’ mechanical design, body, electronics, and software are all tailored to the purpose. Motors are required for the movement of such a robot. As a result, this article includes a complete review of several types of robotic motors as well as a selection guide.

Different types of Robot Actuators

The robot actuators can be classified depending on how they move the output motor shaft and how much energy they convert to do so. We can easily categorize actuators based on the movement of the actuator shaft.

  • Hydraulic Actuator
  • Pneumatic Actuators
  • Electric Actuators

Hydraulic Actuator

Robots that handle big loads employ hydraulic actuators. When compared to other actuators, these can generate a lot of force. Where better speed, accuracy, and stability are required, these actuators are used.

The cylinder and piston arrangement of these actuators is shown in the diagram below. Hydraulic fluid is pumped into the chamber. The piston will be pushed by the fluid pressure, which will move the actuator output shaft. The hydraulic actuators are capable of converting piston motion into linear and rotary motion.

Because of the following reasons, these actuators are utilized in robots:

  • Controllable and precise
  • Simpler to use and maintain
  • Regardless of speed fluctuations, constant torque or force
  • System leaks are easy to detect.
  • Noise reduction

Pneumatic Actuators

Hydraulic actuators, as you may have seen, employ a hydraulic fluid in the cylinder to move the piston. The piston will be moved by the fluid pressure. Instead of hydraulic fluid, compressed air moves the piston in pneumatic actuators.

It can produce linear and rotary movements, just like hydraulic actuators. Pneumatic actuators have several advantages over hydraulic actuators:

  • Environmentally friendly, with fewer pollutants
  • Inexpensive
  • Safe and simple to use

Electric Actuators

Electric actuators are the most often utilized actuators in robotics. Electric energy is converted into linear or rotary motion by this actuator.

The electric actuators might be either AC or DC. DC actuators are commonly used in robotics.

The following are the benefits of electric actuators:

  • Among all actuators, these provide the highest precision.
  • It can easily be networked and programmed. They provide immediate diagnostic and maintenance input.
  • They can incorporate an encoder to control velocity, position, and torque and allow total control over motion profiles.
  • When compared to hydraulic and pneumatic actuators, there is less noise.
  • With no fluid leak, there are fewer environmental risks.

Types of Motors

In the industry, there are many different types of motors. There are specific motor types that are commonly employed in robotic applications. Each motor is employed for a certain function. The motors assist in the robot’s movements as well as work as actuators in the robot’s mechanical architecture.

The following are the subtypes of motors commonly utilized in robotic applications:

  • DC geared motor
  • AC motor
  • DC motor with brushed finish
  • Servo motor
  • DC motor without brushes
  • Motorized stepper

DC geared motor

Brush DC motors have been upgraded to become geared DC motors. The motor is equipped with a gear assembly. The rotational speed of the motor is measured in RPM (RPM). With the help of gear assembly, the motor’s speed is lowered as the torque increases. The speed of the DC motor can be lowered while the torque is increased by utilizing the right gear combination. This ensures that the motor rotates steadily and that it can be halted or altered at speed in a controlled manner.

The H-Bridge circuit, which permits voltage to be transmitted across a load in either direction, is required to regulate the DC motor. The integrated circuit L293D is a dual H-bridge motor driver (IC). Because they take a low-current control signal and convert it to a higher-current signal, motor drivers operate as current amplifiers.

The motors are driven by this increased current signal. It has 16 pins that are configured as follows:

Figure 1 – Configuration of PINs in a DC Motor

AC motor

AC current is used to power AC motors. They are typically utilized in heavy-duty applications that demand a lot of torque (high load hauling or load-bearing capacity). As a result, these motors are found in robotic assembly lines in manufacturing sites. AC motors are rarely utilized in moveable robots because they are often driven by DC sources either the batteries or battery series.

DC motor with brushed finish

Brushes are used to carry current between the source and the armature in brushed DC motors. There are various types of brushed DC motors, but permanent magnet DC motors are employed in robotics. The torque to inertia ratio of these motors is well known. Brush DC motors can produce torque 3 to 4 times that of their rated torque. Brush DC motors are made up of six parts: an axle, a commutator, an armature, a stator, magnets, and brushes.

Furthermore, there are two terminals on Brush DC Motors. When a voltage is delivered across the two terminals, the Brush DC Motor’s shaft receives a corresponding speed. The stator, which encompasses the housing, permanent magnets, and brushes, and the rotor, which includes the output shaft, windings, and commutator, make up a Brush DC Motor. The stator remains motionless while the rotor revolves around it. The stator creates a magnetic field that is stationary and surrounds the rotor.

Servo motor

When accurate rotational motion is required, servo motors are typically employed. Robotic arms and angle control applications typically use them. The Servo Motor lesson will teach you more about servo motors and how to control them.

DC motor without brushes

Brushless DC motors are built similarly to brushed DC motors, but they are controlled by closed-loop controllers and must be powered by inverters or SMPS. Permanent magnets revolve around a fixed armature in these motors. They have a closed-loop electronic controller instead of a commutator assembly, as opposed to Brush DC motors. These motors are typically found in industrial robotics applications that demand precise motion and positioning control. These motors, however, are relatively expensive and have a complicated structure and circuitry.

Stepper motor

The rotation of a stepper motor is divided into numerous stages. A stepper motor rotates by a defined number of angular steps, similar to how a servo motor rotates by a specific angle. The Tutorial on Stepper Motor will teach you more about stepper motors.

Tips for choosing a Robot motor

Now that you’ve finished with the major idea behind your app, it’s time to focus on the finer points of your robot motor. The following should be prioritized:

  • Loads
  • Velocity
  • Accuracy
  • Costs
  • Repeatability
  • Consumption of energy
  • Reliability
  • Factor of appearance

Our Takeaway

Use the suggestions above to create your robot motor selection checklist, or contact us to learn more about how our R-Drive servos may help you create the robot of your aspirations.

We hope you find the information we’ve provided above to be comprehensive and useful.

        NEED HELP FOR THE RIGHT MOTOR FOR YOUR PROJECTS?

                      Please contact us R&D department for best solution

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