Tactile Cobots for Smart Factories

Article By : Neil Bellinger

Regardless of the size of the business or the application, tactile cobots can provide benefits in a variety of Industry 4.0 scenarios.

Small, lightweight, and designed to operate safely alongside humans, cobots are ideal for the modern smart factory.

Some of the newest models include state-of-the-art sensors and software that allow them to feel and identify the objects being touched, increasing their dexterity and their suitability to a variety of applications.

The first cobot was invented in 1996 and was defined as “a device and method for direct physical interaction between a person and a computer-controlled manipulator.” It was mainly designed for basic pick-and-place applications and used motion resistance to communicate with the operator.

A recent study by the Massachusetts Institute of Technology (MIT) found that human-robot cooperation reduced human idle time by 85%. At the same time, cobots have become more versatile and can be used not only by big manufacturers looking to optimize the workflows for their complex production lines but also by SMEs who require flexible automation solutions but may not have the resources to invest in large systems.

Modern cobots are also more technologically advanced. They can detect objects and people in their environment using vision sensors and slow down or stop to avoid an unintended contact. Their touch-sensing technologies are evolving, too, increasing their applicability and safety in demanding applications that require handling delicate materials safely and precisely, such as in health care.

Regardless of the size of the business or the application, tactile cobots can provide benefits in a variety of Industry 4.0 scenarios.

Delicate object handling

Touch is essential for the effective manipulation of objects and for regulating the pressure applied to an object to avoid damaging the product. With a more effective sense of touch, cobots can be used in applications in which they interact with soft, fragile, or deformable objects.

Tactile sensors can also be used to identify the features of objects and recognize defects and changes. For example, early research from the USC Viterbi School of Engineering used embedded tactile sensors with conductive fluid to simulate human touch, resulting in a robot able to differentiate between the texture of wool and that of cotton.

Quality assurance

Similarly, modern touch-sensing systems use tactile sensors to gather different information about an object, such as shape, size, and texture, and transmit an electrical signal to the controller. They then measure the real characteristics of the objects, producing accurate information and spotting inaccuracies in products.

This is particularly helpful in detecting defects on industrial production lines while cooperating with quality inspectors.

Because they are lightweight and easily deployable, cobots can be moved to different points on the line and can inspect multiple products at once. They are also more cost-effective than employing a team of highly trained inspectors or investing in conventional machine-vision systems that lack precise detection technologies.

Machine tending

Tactile cobots are also valuable for precise object placement when loading parts into a fixture for machine tending.

Their sensing technology can find the exact part location and correct changes in the position or size of the raw stock material by measuring the insertion force.

These various applications make cobots highly advantageous for achieving end-to-end automation and realizing smart factories. Automating every process on the production line has the potential to replace outdated work processes with smart robotic systems and generate business growth for companies regardless of their size.

Preventing collision

There are currently several tactile sensors used in cobots, including piezoelectric, piezoresistive, capacitive, and elastoresistive types. Piezoelectric technologies are used for gathering data from the cobot’s joints and transmitting it to the controller. On the other hand, capacitive sensors can act as proximity sensors, allowing the cobot to slow down when it detects the presence of an obstacle.

Most detection sensors, such as area sensors, are placed outside of the cobot, enabling it to slow down or stop when human workers are close by. Although collisions might still happen, these technologies ensure that the impact is minimized. Tactile sensors are generally embedded at the end of the cobot arm to make navigation more reliable, just as in a human arm, and are equipped with artificial intelligence to avoid collision and allow the cobot to move more efficiently.

In a 2021 research paper from Frontiers in Neurorobotics, Andrea Cherubini and David Navarro-Alarcon found that robot skins equipped with tactile sensors will be most suitable for ensuring safety, cooperation, and coexistence. Robot skin can be modeled after the human central nervous system and use feedback from detection sensors to infer motion commands. Robot skins could be used in surgical operations but also in smart factories to avoid unwanted collisions, giving cobots an enhanced ability to perceive their surroundings and facilitating interactions with humans.

After the most recent advances in machine-vision technology, cobots are now closer to gaining another sense that has been denied to them thus far: the sense of touch. Advancements in tactile sensors allow humans and machines to perform increasingly complex tasks in a collaborative environment to achieve increased productivity and accuracy. An agile work environment that plays on the strengths of automation is key to a successful business but is also essential for achieving a smart and modern factory.

This article was originally published on EE Times Europe.

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