The Main Purpose of Robot Manipulators

robotic arm working in an industrial factory for automated production

The applications of industrial robotics are as varied as the industries that use them. Defining said applications can be an arduous, if not impossible, task. And while many of those applications involve the use of highly sophisticated components and technologies – many of which will forever remain unknown to the layperson – it’s nearly impossible to think of industrial robotics without conjuring images of the mechanical appendages that have made robotics such an integral part of our world.

These appendages, also known as robotic manipulators, are used in all manner of applications, ranging from safely moving heavy materials from one location to another to assisting a surgeon with microsurgery. These manipulators are used to move and control objects and materials with speed and precision that simply cannot be performed by humans.

In this article, we’ll further define what robot manipulators are, explore the different types of manipulators, and dig deeper into the various applications they’re used for.

What is a Robotic Manipulator?

In a very broad sense, robotic manipulators can be defined as electronic devices that are specifically designed to allow a robot to interact with its environment, namely by moving objects from one place to another, or effectuating a change to the material or medium it is working with. Due to the sheer number of actions a manipulator can be programmed to perform, one could draw an anthropomorphic comparison between a robotic manipulator and the function of the human hand. Manipulators can generally be found at the end of a robotic “arm” a position which, in addition to increasing the number of tasks it can perform, further strengthens the comparison to human anatomy. Robotic arms and manipulators work very well together; robotic arms, for their part, consist of different segments that provide the necessary range of motion to perform the required task, while the manipulator (or gripper, as some prefer) is responsible for the actual manipulation of the object in question.

The Different Types of Robotic Manipulator Arms

While robotic arms do have a certain amount of range of motion (usually around 3 to 6 degrees), The range of motion is determined by the joints that are connected to various segments of the arm (think shoulder, upper arm, forearm, and wrist). The type of robotic arm used is generally determined by the space in which it operates, and the range of motion that it requires to perform the task. Below are some of the most common types of robotic manipulator arms.

Articulated Robot – Perhaps the most commonly recognized type of robotic manipulator arms, articulated robots offer the most degrees of freedom possible and can consist of between 3 and 6 revolute joints (a revolute joint connects two segments and offers 1 degree of rotational freedom). As one can imagine, given the relatively high number of joints and segments, the greatest advantage of an articulated robot is the wide range of motion that it can employ.
SCARA Robot – These types of robotic manipulator arms consist of one prismatic joint which is responsible for movement on the Z axis and two additional revolute joints. A prismatic joint allows two connected objects to slide along a common axis while prohibiting rotational movement. SCARA robots are commonly used to lift heavy items in industrial settings,
Gantry Robot – These robotic manipulator arms leverage a type of rail system that allows them to move along the X, Y, and Z axis. Like SCARA robots, gantry robots are well equipped to handle incredibly heavy payloads.
Spherical Robot – Spherical robots consist of two revolute and one prismatic joint. The former provides rotational range of motion while the latter joint allows the arm to extend its reach. Typically, spherical robots are used for welding.
Parallel Robot – These types of robotic manipulator arms are typically installed using an overhead mounting system and will consist of anywhere from 3 to 6 arms, each with its own revolute or prismatic joint, as required.

Various Types of Manipulator End Effectors

Much like the style of robotic arms described above, robotic manipulators can also be sorted by the tools used at their extremities. Commonly referred to as “end effectors”, these tools are generally a type of gripper that are made of different materials and/or contain varying number of “fingers”.

Electric Gripper – As the name implies, the fingers of an electric gripper are controlled by individual electric motors. These motors allow the gripper to firmly grip objects and manipulate them with a high degree of speed and accuracy.
Pneumatic Gripper – Compressed air and not electric motors control the gripping strength and prowess of the gripper’s appendages. For context, pneumatic grippers provide greater gripping strength than electric grippers.
Magnetic Gripper – Rather than relying on electricity or compressed air, magnetic grippers rely on magnetic forces, though they can only be used to manipulate ferrous metals.
Mechanical Gripper – Like magnetic grippers, mechanical manipulators do not rely on conventional power to perform a given task. Instead, they leverage a different design that employs appendages like prongs to facilitate the manipulation of objects.
Suction Grippers – This type of gripper utilizes air pressure in the form of a vacuum to pick up and manipulate objects.

Applications of Robot Manipulator

Even to those that are not familiar with modern industrial practices, it’s not surprising to learn that robot manipulators are widely used in the manufacture of all types of products due to their consistent and reliable performance, speed, and accuracy. Their strength and precise movements mean that while they can move very large and heavy objects, they can also be trusted with exceedingly delicate operations.

As alluded to at the beginning of this article, robotic manipulators are increasingly used for medical purposes to perform complex surgeries and reduce the invasiveness and healing time associated with more routine procedures.

In addition to applications on dry land, robot manipulators are also used in perilous environments where human workers are few and far between. One need only look towards the stars or deep sea mining and drilling operations to understand just how versatile these technologies are.

Robotic Manipulators are Vital Wherever Robotics are Used

Robotic manipulators are arguably one of the most important pieces of modern manufacturing; their implementation contributes to efficient and automated assembly lines in all kinds of industries. As we’ve seen, however, their use goes well beyond the manufacturing sector. It stands to reason that the continued development of sophisticated robotic manipulators will only gain traction due to their accuracy, efficiency, and their ability to reach otherwise inaccessible places.

If you’re interested in developing or maintaining the next generation of robot manipulators, begin your journey by enrolling in the Robotics Technician Program offered by George Brown College.