Robot Actuator : Types, Design, Working & Its Applications

We know that robots are advanced and highly intelligent electromechanical devices that can perform a number of daily tasks. This device is capable of responding to its surroundings & making actions to attain a specific task. Robots are made with different components but one of the significant components is the actuator. Generally, actuators are used in almost every machine around us like electronic access control systems, mobile phone vibrators, household appliances, vehicles, robots & industrial devices. The general actuator examples are; electric motors, jackscrews, stepper motors, muscular stimulators within robots, and many more. This article gives brief information on a robot actuator – working with applications.

What is a Robot Actuator?

An actuator that is used in robots to make the wheels of the robot turn or robot arm joints turn or to open/close the gripper of the robot is known as a robot actuator. There are different types of robotic actuators are available based on the load involved. Generally, the load is associated with different factors like torque, force, accuracy, speed of operation, power consumption & precision. The working principle of a robot actuator is to change the energy into physical motion and most actuators generate linear or rotary motion.

Types of Robotic Actuators

Robotic actuators are classified into two types according to the requirements of motion like linear motion & rotational motion.

For Linear Motion:

There are two types of actuators used in robots for linear motion activity they are; linear actuators and solenoid actuators.

Linear Actuators

Linear actuators in robotics are used to push or pull the robot like move forward or backward & arm extension. This actuator’s active end is simply connected to the robot’s lever arm to activate the such motion. These actuators are used in a number of applications in the robotics industry.

Solenoid Actuators

Solenoid actuators are special-purpose linear actuators that include a solenoid latch that works on electromagnetic activity. These actuators are mainly used for controlling the motion of the robot and also perform different activities such as a start & reverse, latch, push button, etc. Solenoids are normally used in the applications of latches, valves, locks, and pushing buttons which are controlled normally by an external microcontroller.

For Rotational Motion:

There are three types of actuators used in robots for rotational motion activity they are; DC motor, servo motor, and stepper motor.

DC Motor Actuators

DC motor actuators are generally used for turning robotic motion. These actuators are available in different sizes with torque generation capability. Thus, it can be utilized for changing speed throughout rotating motions. By using these actuators, different activities like robotic drilling & robotic drive train motion are performed.

Servo Actuators

Servo motor actuators in robotics are mainly used to control & monitor rotating motion. These are very superior DC motors that allow 360 degrees of rotation, but, continuous revolution is not compulsory. This actuator simply allows halts throughout a rotating motion. By using this actuator, the activity like pick and place is performed. To know how a Pick N Place robot works click on the link.

Stepper Motor Actuators

Stepper motor actuators are helpful in contributing to repetitive rotating activities within robots. So these types of actuators are a combination of both DC & servo motor actuators. These stepper motor actuators are utilized in automation robots where repeatability of activity is necessary.

Robot Actuator Design

We know that there are different types of actuators used in robots. Here we are going to discuss how to design a linear actuator that is used in robotics for changing rotating motion into a pull/push linear motion. So this motion can be used to slide, drop, tilt or lift materials or machines. These actuators provide clean & safe motion control that is very efficient & maintained free.

Power

The first consideration while designing a robot actuator is Power. To obtain mechanical power out, it is essential to have power in. So, the amount of mechanical power out can be defined by the load or force to be moved.

Duty Cycle

The duty cycle can be defined as how frequently the actuator will work & the amount of time it will use. The duty cycle is determined by the actuator’s temperature when it is in motion since power is lost throughout the heat.

When all the actuators are not the same, then there is a difference within their duty cycles. One more factor is the load, which is particularly true of DC motors whereas other factors that can determine the duty cycle are loading characteristics, age & ambient temperature.

Efficiency

The actuator efficiency simply helps in understanding how it will work while in operation. So, the actuator’s efficiency is found by separating mechanical power generated by electrical power.

Actuator Life

There are many factors that will extend the actuator’s life are; staying in the rated duty cycle, reducing side load, and staying in the recommended voltage, force, and extreme environments.

Working

Robot actuators are mainly designed for ease of use & efficiency. The design of a linear robot actuator is the inclined plane that starts with a threaded lead screw. This screw provides a ramp to generate force that works along with a larger distance to move any load. The main purpose of robot actuator design is to provide pull/push motion. So, the required energy to provide the motion is manual or any energy source like electricity, fluid, or air. These actuators generally move car seats forwards & backward, open automatic doors, computer disk drives opening and closing.

Robot Actuator Failure

The robot actuator failure mainly occurs due to many reasons. So these actuators can experience different failures like stuck joints or locked, free-swinging joints & total or partial loss of actuation efficiency. So, these failures will affect robot behavior if the controller of the robot has not been designed with sufficient fault tolerance.

How to Choose an Actuator for your Robot?

Robot actuators are used for different purposes, so there are many aspects to consider while selecting actuators like

Purpose & Intended Functionality

The necessary actuator type for a specified application mainly depends on the purpose of a robot as well as the intended functionality.

Physical Requirements & Constraints

Whenever the type of actuator is decided to use, then developers must look at the physical requirements & constraints. Because the weight & physical size of the actuator plays a key role while arranging the actuator in the robot otherwise a heavy actuator on a tiny robotic arm may cause to fail the arm in its own weight.

Strength & Power

Based on their particular usage, developers must ensure the strength and power of a specified actuator to perform the task.

Communication Protocol

The communication protocol should also be considered while selecting an actuator for the robot. Many actuators simply support communications with PWM (pulse width modulation) whereas some actuators support serial communications.

Mounting Space & Options

Developers should verify the mounting space obtainable in or on the robot & the mounting options given by the actuator itself. Because some types of actuators are available with separate mounting hardware that allows you to mount the unit within different orientations whereas others are available with integrated mounting points, which are installed into a particular position & orientation.

Advantages

Robot actuator advantages include the following.

• Less cost
• Its maintenance is easy.
• These are accurate.
• Easy to control.
• Power conversion efficiency is high.
• Safe & simple to operate
• Less noise.
• These are very clean & less pollution to the atmosphere.
• These are very easy to maintain.

Robot actuator disadvantages include the following.

• Overheating within fixed conditions.
• Need special safety within flammable environments.
• Need good maintenance.
• Fluid leakage will create ecological problems.
• Loud & noisy.
• Lack of accuracy controls.
• These are very sensitive to vibrations.

Robot Actuator Applications

The applications of robot actuators include the following.

• The actuator is a very significant component in robotics which changes the external energy into physical motion depending on the control signals.
• The electrical actuators in robotics are used to change the electrical energy into rotary or linear motion
• Actuators generate forces that robots use this force to move themselves & other objects.
• Actuators are associated with robotics, devices, or prosthetic arms which need to move & bend.
• The linear actuators within robotics change electric energy into linear motion.
• An actuator is responsible for controlling & moving a system or mechanism.

Thus, this is all about a robot actuator – working with applications. The actuator within a robot is an essential component that works as the joint for the robot to move the robot rotate, arm up & down & it changes energy into mechanical motions. The most common energy source to power actuators is electricity, however pneumatic & hydraulic energy may also be utilized. So, some unique hydraulic-powered actuators are used to generate high power & are shock-resistant. Here is a question for you, what are the different components used in robots?