Tactile sensors are pressure-sensitive devices used to detect and measure objects by touch. They are an important part of robotics, as they allow robots to interact with their environment in a safe and controlled manner.

For example, a tactile sensor could detect when a robot is being touched or when an object is being grasped.

What are Tactile Sensors?

Tactile sensors come in many different shapes and sizes. Some are large and flat, while others are small and round. Some tactile sensors can measure only a single point of contact, while others can measure multiple points of contact simultaneously.

There are many different ways to make tactile sensors. Some use special materials that change color when pressure is applied, while others use piezoelectric materials that generate electricity when pressure is applied.

Tactile sensors have many different applications in robotics. They can help robots grasp objects, navigate their environment, and avoid obstacles.

How do Tactile Sensors Work?

Tactile sensors work by sensing changes in pressure, force, or vibration. They can be either active or passive.

Active tactile sensors require an external power source, such as a battery, to operate.

Passive tactile sensors do not require an external power source and instead rely on the energy from the event that they are sensing (such as a touch or a vibration).

They are an important type of sensor for robots because they provide information about the environment with which the robot interacts. This information can be used to control the robot’s movements and avoid collisions.

There are several different types of tactile sensors, including:

– Pressure sensors: These sensors detect changes in pressure and can be used to measure things like weight or grip force.

– Force sensors: These sensors detect changes in force and can be used to measure things like wind speed or acceleration.

– Vibration sensors: These sensors detect changes in vibration and can be used to measure things like engine speed or machine movement.

What are the Benefits of Using Tactile Sensors on Robots?

There are several benefits of using tactile sensors on robots.

• First, they can provide information about the environment that is unavailable through other senses. For example, they can detect changes in texture or surface roughness. This information can help the robot navigate its surroundings and avoid obstacles.
• Second, tactile sensors can be used to detect objects and determine their properties, such as size, shape, and hardness. The robot can use this information to grasp and manipulate objects.
• Third, tactile sensors can provide feedback to the operator of a robotic system. For example, they can provide haptic feedback that simulates the feeling of touching an object. This can help the operator more easily control the robot and perform tasks more accurately.

In conclusion, tactile sensors are a crucial element in the development of robotics technology. Without them, robots would be unable to interact with their surroundings in a safe and effective manner.

With the help of tactile sensors, robots can avoid obstacles, identify and pick up objects, and even respond to human touch. As robotic technology continues to evolve, tactile sensors will likely play an increasingly important role in the world of robotics.

Tactile sensors are the newest sensors that affect how robots interact with the environment around them and deliver data-driven results. Recently, Meta (a parent company of Facebook) announced the design of new tactile sensing hardware for robots. The GelSight-Style fingerprint sensor works on suspended magnetic particles and uses machine learning technology to gather pertinent information.

Most backend function of Meta is dealt with by Artificial intelligence, which is one of the essential aspects of designing a robot. Although Facebook was against robotics, the boom in the sphere, combined with AI technologies, has driven the company to work on robotics. People involved in AI are researching the loop of perception, planning, reasoning, and action and getting feedback from the environment and the objects around it.

Robotics can be used for maintaining automatic data centers, telepresence, and other areas where tactile sensors deliver their work, which is a good enough reason for the company to begin and extend its research about the use of tactile sensors in robots.

Tactile sensors in robots

Humans are good at understanding the environment and everything around it from the subconscious perspective after many years of using it. However, robots and AI systems need to possess this experience, and there is no clear path to getting them to that level. But touch sensors (one of the tactile sensors) pave a pathway for humans to discover the ‘subconscious’ level of the robots.

The GelSight Style sensor uses a tactile sensor, which can convert any touch problem to a vision-based problem with the help of an array of LEDs that illuminate when there is a touch. The result of this robot is a detailed image or video of the object that the finger pad is pushing against, with the help of a camera in the finger pad. This can be helped in manufacturing DIGIT sensors which also provide a low-cost option for tactile sensing in robots.

Another announcement made by Meta is the ReSkin sensor which uses a tactile sensing skin to make an open-source, low-cost robotic system that helps the robots make sense of touch.

ReSkin is a flexible sheet of 2mm thickness with many magnetic particles mixed randomly. The sheet is placed on top of a magnetometer which can deform when it is in contact with an object. The sheet deforms, and the magnetic particles are squished, which changes signals in the magnetometer. Even if the skin is damaged, it can easily be replaced by peeling off and pasting another sheet. These types of sensors help determine an object in the environment by touch.

Conclusion

Tactical sensors in robots have been paving more excellent paths to exploring new ways in which robots can help humans ease the task. The involvement of big companies like Meta proves the topic’s vastness and aids in further discovery of the use of sensors in building robots.

Robotics is an industry that is constantly evolving, and with that evolution comes new and innovative ways to create more realistic and lifelike machines.

One area that has seen significant advances in recent years is tactile sensing. Tactile sensors are used to detect touch and pressure, and they are an essential part of creating robots that can interact with the world more naturally.

Introduction to Tactile Sensing

There are many forms of tactile sensing, each with different advantages and disadvantages. The most common forms of tactile sensing are capacitive, piezoresistive, and optical.

Capacitive sensors are the most common form of tactile sensor. They work by detecting changes in capacitance, which is the ability of a material to store an electric charge.

Piezoresistive sensors work by detecting changes in resistance, which is the ability of a material to conduct an electric current.

Optical sensors are the least common form of tactile sensor. They work by detecting changes in light intensity or reflectivity.

Tactile sensing is an important technology for many applications, including robotics, medical devices, and consumer electronics.

The Future of Tactile Sensing in Robotics

The future of tactile sensing in robotics is looking very promising. With advances in technology, sensors are becoming smaller, more sensitive and more affordable. Robots with tactile sensors can perform more delicate tasks and naturally interact with their surroundings.

Healthcare

Robots equipped with sensitive tactile sensors could help care for elderly or disabled people. They could help with things like bathing, dressing and grooming. They could also be used to assist surgeons during delicate procedures.

Search and rescue missions

Robots equipped with these sensors could navigate debris and rubble to find trapped people.

Manufacturing industry

Robots equipped with these sensors could handle small parts and assemble products with a high degree of accuracy.

With continued advances in technology, robots equipped with these sensors will become increasingly commonplace and will have a profound impact on many different industries.

Future Trends in Tactile Sensing

Miniaturization

As sensors become smaller and more compact, they will become more suitable for use in more miniature robots and applications where space is limited.

Use of flexible sensors

These devices would be able to conform to the shape of an object, making them ideal for tasks such as gripping or handling delicate items.

The advancement of 3D printing technology

By enabling the rapid creation of custom sensor arrays, 3D printing could allow the development of unique sensors explicitly tailored for a particular application or task.

Piston Stuffing with Robotic force and tactile sensing

The use of robotic force and tactile sensing is becoming increasingly common in piston stuffing. This technology allows for a more precise and efficient stuffing process, as well as increased safety for workers.

The future of tactile sensing in robotics holds much promise. By harnessing the power of a touch, robots will be able to interact more effectively with their surroundings and carry out tasks more efficiently.

Tactile sensing technology is still in its infancy, but it is rapidly evolving. In the coming years, we can expect to see ever-more advanced tactile sensors being developed for use in a variety of applications. Ultimately, these sensors will help make robots even more versatile and capable than they are today.

Tactile sensing or touch sensing is one of the primary challenges in robot building and manipulation. The agile environment in which a robot works also requires pressure sensors to determine the careful operation of an object.

A robot skin is developed to mimic the touch senses perceived by human skin, integrating different types of tactile sensors. By doing so, a robot ‘feels’ many classes of objects – flexible, rigid, hard, soft, fragile, etc. This allows the robots to work in close proximity to humans while performing tasks of higher risk factors.

Building robots using tactile sensors

Cobots are robots that work hand-in-hand with humans in high-risk environments. The first cobot was built in 1996 for pick and place applications, which were communicated using motion resistance technology through computerized programs. Since then, cobots have come a long way in working with humans and detecting the environment around them with the help of vision and other types of sensors.

Modern cobots can take corrective actions with slight decision-making skills and sophisticated software. In addition, tactile sensors are now used to increase these cobots’ applicability and safety, especially in environments requiring delicate handling of objects, such as healthcare.

The use of tactile sensors

Piezoelectric, Pierzoresistive, capacitive, and electroresistive are the four types of tactile sensors in use today. A combination of all these types is used in building robots and cobots by transmitting their actions to a controller, thereby managing their sensitivity towards an object and their motion in different directions.

For some applications, detection sensors are placed outside the body of a collaborative robot which helps recognize human workers when they work closely. These sensors signal the robots to slow down or stop when an object is near.

Although collisions can take place to a certain extent, the impact of the collision can be minimized. However, tactile sensors are empowered with intelligent software technologies to improve the readability of these collaborative robots.

Precise object handling

Tactile or touch sensors are used in applications requiring precise object placements, like loading parts into a machine. The sensitive sensing technology provided by tactile sensors embedded in a robot’s body will help determine the exact location and the correct position to place the stock material with the help of insertion force.

Modern-day touch sensing technologies use tactile sensors to study the real-time parameters of an object like the shape, texture, size, etc. and determine highly accurate data of the object, which can also help determine defects and damages in an object. For example, cobots powered by tactile sensors can be used in surgery to interact with more fragile and deformable objects. However, multiple tactile sensors should be used to build empathetic robots, integrating them with AI and machine learning technologies.

The world of robotics is increasing by the second, and its applications have directly impacted the human world and how we process data. It is a no-brainer that robots use sensors to help them mimic human movements, to perform specific tasks. Although the integration of vision sensors, motion sensors, and many others had been introduced long back to the robotics world, the idea of touch sensors, also called tactile sensors, was often overlooked.

However, over the years, researchers started understanding the value of the sense of touch in robotic development. Having tactile sensors in robots enables the working of other sensors for power, machine vision, freedom of movement, and many more tasks.

Robotic touch technology and applications

One of the best touch sensor technology used in today’s robotics world is built by force torque sensors and the mechanism of low-resolution pressure sensors in the contact points of grippers. These tiny contact points act as the fingertips of a robot. Many of the present-generation robots use this technique for touch sensing. Integrating these sensors in the tips of robot fingers helps determine the system and object edges and results in close manipulation of the objects, just like the mechanism in a human body. This feature has also helped develop cobots, which work in sensitive environments close to humans.

Simple piezoresistive, capacitive, or piezoelectric technologies can be used to create such tactile sensors. However, the capacitive sensors have a higher advantage than the others, as they help the robots to solve their movements when they’re close to the object, avoiding wasting power and causing damage. In addition, a discrete set of temperature, moisture, and other sensors are attached to the gripper pads to provide a more human-like motion for these robotic hands.

Sensor fusion

Sensor fusion means integrating several sensors to build a versatile robot that can perform complex tasks, which helps determine an object’s physical properties. For instance, a robot with a capacitive tactile sensor cannot alone pick up metal and plastic objects as they have different capacitors.

Hence, when multiple sensors are overlapped in different detection areas, they can be relied on to produce data on critical scenarios. Also, having multiple sensors can help detect the robot’s safety and efficiency. For instance, a contradictory reading from two different tactile sensors indicates a problem in robot functioning, which also helps easily detect sensor failure.

Accurate feedback from the tactile sensor helps maintain the safety and efficiency of cobots- robots that work relatively efficiently with humans. Fortunately, modern machine learning and AI technologies are great at programming and integrating different sensors to make decisions. Hence, AI also plays a crucial role in robot touch sensing, giving a robot human-like skin with many embedded tactile sensors.

Tactile sensors measure forces in response to physical changes and environmental interactions. One of the leading human aspects of detecting a change in the environment is by touch. The same principle is also applied in robots to detect changes in the environment and statistically analyze sensor data.

Tactile sensors are modeled to a biological sense of human touch, which is further provoked by the mechanical stimulation of the skin. This working principle helps robots, security systems, and computer hardware to measure data and analyze it to determine results in various fields. One of the typical applications of tactile sensing technology is in robotic arms, also called robotic tactile sensing.

The importance of tactile sensors in robotic applications

One of the significant challenges facing the robotic industry is that the dexterity of fingers makes it difficult for the robotic systems to do 95% of manual jobs like preparing a drink, folding clothes, cleaning a chandelier, and others. Replacing these kinds of manual labor with robots includes high precision, flexibility, and object detection, which can be achieved by enhancing the accuracy of measuring and controlling robotic fingers. This ensures that an object’s fragility is well-determined and not crushed by the gripper, which is generally a semiconductor wafer handler. Although the load cells provide reliable hope in robots for performing such actions, they have been limited in use due to their bulk structure. Hence, multiple load button cells are used as tactile sensors in industrial robots to measure the force they produce when they are in contact with an object.

Working

Many research laboratories continue to explore the vastness of robotic tactile sensors, especially in developing high-precision robots to help test, measure, and produce quality data in the robotic tactile sensing space. The presence of miniature load buttons provides succession by one step in detecting the sensitivity and fragility of objects. Tiny load buttons on the robot’s fingertips are force sensors mounted on each robotic finger’s tip. The tactile sensors placed in the tips manage to calculate the force required to handle the objects with utmost precision. The entire tactile sensor system in a robot is connected to a USB solution, where the researchers can stem the force needed to be applied directly on a computer to which the USB is connected. Drawing a graph of the findings makes it easier for the researchers to calculate the force required to pick up an object.

One of the main applications of designing a robot with tactile touch capability is to develop prosthetics using artificial touch technologies. The functional requirements of developing such robots include the following:

• Contact detection of objects
• Lifting and replacement of an object
• Detection of size and shape for object recognition
• Detection of tangential forces to prevent object slip
• Estimation of grip forces
• Tracking all the contact points during manipulation
• Detection of all the dynamic and static forces around the object

Tactile sensors are an important part of any robot’s toolset. They provide information about an object’s surface properties, such as texture, hardness, and weight. This information can be used to improve a robot’s grip on an object or to help the robot avoid damaging fragile items.

Robotic sensors

Robotic sensors measure and detect physical parameters like temperature, pressure, speed, etc. They play an essential role in enhancing the performance of robots by allowing them to gather information about their surroundings and react accordingly.

There are many different types of robotic sensors available, each with its own unique set of capabilities. The most common type of sensor is the tactile sensor, which detects contact and pressure.

Force and touch

The sense of touch is especially important for robots, as it allows them to interact with their environment more naturally.

When choosing a sensor for your robot, consider the specific needs of your application. For example, if you need a sensor that can detect very light touches, you will want to choose a sensor with high sensitivity. On the other hand, if you need a sensor that can withstand heavy impacts, you will want to select a sensor with high durability.

In robotics, force sensors measure the interaction between a robot and its environment. This information can be used to control the robot’s behavior or movements.

Detecting the environment

A tactile sensor is a pressure-sensitive device that can detect the environment around it. By measuring the amount of pressure applied to the sensor, the robot can determine how far away objects are, what they are made of, and whether or not they are moving.

Temperature

Temperature sensors are used to measure the temperature of an object or environment. They are commonly used in robotic applications to track the temperature of the robot’s components and surroundings. Temperature sensors can be used to monitor the health of your robot and its environment and to optimize its performance.

Temperature sensors are typically classified by their operating principles, such as thermocouples, resistance temperature detectors (RTDs), or semiconductor-based sensors.

• Thermocouples are the most common type of temperature sensor used in industrial applications due to their high accuracy and wide operating range.
• RTDs offer greater accuracy than thermocouples but are limited to a narrower range of temperatures.
• Semiconductor-based sensors are often used in consumer electronics due to their small size and low cost.

Light

Tactile sensors can also determine the direction and intensity of the light. This information can be used to enhance your robot’s performance.

For example, if you are using a robot to navigate a dark room, you can use the tactile sensor to determine where the light is coming from and adjust your robot’s course accordingly. You can also use the tactile sensor to detect objects in your path and avoid them.

A tactile sensor is a great way to add an extra level of precision and control to your robot. With the right understanding of how they work and how to use them, you can take your robot’s performance to the next level.

A tactile sensor can help improve your robot’s performance by providing information about the surface it is touching.

Tactile sensors, also called touch sensors, help determine an object’s physical characteristics when they are close to the objects. They are also called transducers which are used in various applications worldwide.

Psychophysical studies have determined the importance of touch, which is used for interpretation, extraction, and manipulation of the object within our range that is registered in various types of receptors like thermoreceptors, nociceptors, mechanoreceptors, etc., which are connected to a system to scrape the necessary information.

Tactile sensor technologies

Tactile sensors are sensitive to static or dynamic forces, which can be used for proprioception or exteroception. These sensors measure the internal states of the robot, while the latter is used to measure physical characteristics like the sense of touch in the environment.

All tactile sensor technologies are classified based on the transduction method, which helps convert stimuli from the external environment into intelligent systems. The most widely used tactile sensors in robots are based on the following transduction methods:

• Capacitance
• Piezoresistivity
• Optics
• Magnetic
• Binary
• Piezoelectric

Capacitive sensors

These types of sensors measure the variations in capacitance from an applied load over a parallel plate capacitor in the sensor. Capacitive sensors are susceptible to the external field, which in robotics is called taxels mimic the operation of human fingers. Since these sensors can be fabricated in compact spaces, they are used at the fingertips of robots.

Piezoresistive sensors

These sensors detect the resistance of a contact when an external force is applied. These sensors are generally fabricated on conductive rubber made of piezoresistive ink. These sensors produce a wide dynamic range, good load tolerance, durability, and low-cost fabrication. These sensors are used in robots where high accuracy is not a prim criterion.

Optical sensors

These sensors transduce mechanical contact, movement, and pressure into changes in refractive index or light intensities, detected using state-of-the-art vision sensors. They provide robustness to electrical interference with the capability of resolving high-level problems. Due to this, they are used in dexterous object manipulation and various other robotic systems. It is also used as one of the primary sensors in a three-finger robot hand to grasp particular objects in close vicinity.

Piezoelectric sensors

They produce an electrical charge when a force, pressure, or deformation is applied to them. They are best used to measure vibrations and are widely used for their high-frequency response, sensitivity, and availability in various forms like ceramics, crystals, etc. They are also preferred for the fabrication of tactile sensors, given their workability, flexibility, and chemical stability. Recently, they were best used in integrating tactile sensors with robotic grippers in robotic hands. Along with binary sensors, they are the best choice for using them in five–finger robotic hands as well

Tactile sensors are based on a range of different technologies they are utilized in. They’re broadly defined as data acquisition devices designed to sense different properties via direct contact with the object. Robotic applications have expanded their horizon in agriculture, healthcare, and autonomous systems in various unstructured environments where tactile sensors are highly beneficial. Their deployment helps measure, detect, and convert information, mainly acquired by physical contact with the objects.

Although tactile sensing has expanded exponentially in recent years, they are still underdeveloped compared to vision sensing. Researchers predict that this underdevelopment is due to the complexity of the sense of touch.

Applications of robotic tactile sensors

In 1980, robotics was initially determined as the study of perception and action and their intelligent interaction with the environment. Today, touch sensors’ integration has played a significant role in the robust development of flexible and adaptable robots capable of exploring different environmental sectors and safely interacting with humans.

Various robotic platforms use tactile sensors in their developments, like fingerprints, hands, forearms, and torso. This has helped study embodied cognition, perception, recognition, learning, and interaction.

Robotic fingerprints

Robotic fingerprints built with tactile sensors are generally equipped with piezoelectric elements, which recognize objects’ properties like shape, texture, etc. Studying and understanding these properties are used to determine experimental procedures like pushing, squeezing, sliding, and tapping of different objects. The use of pressure and force sensors has also played a significant role in object detection and manipulation. For example, the use of tactile sensors in prosthetic hands helps in mimicking the natural motion of a human hand.

Object and shape exploration

Different perception and control approaches are used to determine the object and its shape in various tactile robotic platforms. For instance, the Puma robot is integrated with planar tactile sensors, which help extract object edges and their orientation based on the geometrical moments. A similar use of geometrical moments is used in the KUKA arm with planar tactile sensors, which can recognize the shape and texture of various objects in contact with its fingertips.

Rolling and enclosing exploration

Based on the kurtosis observed on the tactile fingerprint of a five-finger robotic hand, the rolling and enclosing features can be explored. For example, the iCub humanoid robot using tactile sensor information from hands and fingertips achieved higher accuracy in the enclosure procedure for an object recognition task. In recent years, the robotic hand developed by Barrett Hand Inc., which is covered by tactile sensors in its fingertips and palm, has been used to understand dexterous manipulations and study the perception of touch.

Conclusion

There are a plethora of benefits provided by the tactile or touch sensors to develop robots that mimic human tasks. A range of technologies has also been developed around these sensors, each with its advantages and limitations.

A tactile sensor is a small device that responds to stimuli and measures the information from interacting with its environment. These sensors are modeled to respond to physical environmental changes and can detect mechanical stimulation, temperature, and pain. They find their use in robotics, security systems, and computer hardware. A touchscreen device is one of the most common examples of tactile sensors.

There are different types of tactile sensors:

• Optical
• Capacitive
• Elastoresistive
• Piezoresistive
• Piezoelectric

Since the modification of sensors has come a long way, it is primarily used in robotics to control mechanical arms, aircraft, and other fields.

Uses of tactile sensors

Although there are innumerable applications of these sensors in different fields like medicine, robotics, aeronautics, etc., in this article, we will talk about their uses in designing robots.

Robots are machines designed to handle tasks involving precision, dexterity, or interaction with particular objects. A sensor can help a robot provide the necessary functionality, equivalent to human tactile ability. One of the main advantages of tactile sensors in robots involves complementing visual systems and providing additional information when the robot begins to get hold of an object. For example, since the mechanical properties of an object at grip cannot be determined visually, tactile sensors were introduced to measure its coefficient of friction, thermal conductivity, stiffness, center of mass, thermal conductivity, and other factors.

There are several classes of tactile sensors in robots, each performing different types of tasks advocated for monitoring and manipulation.

Optical–based tactile sensors

In recent years, several tactical sensors have been introduced in the market, which provide camera-like technologies to produce data with high resolution. For example, Samsung uses see through your skin sensor (STS), which uses a semi-transparent gel to provide precision imaging with high resolution.

Pressure array sensors

The tactle, an element of a tactical sensor, can detect regular forces. This means their interaction provides high-resolution images when the object comes in close contact with the sensors in a robot. With its spatial resolution and sensitivity to forcing, wiring and signal routing are also essential factors for system integration. Hence, pressure sensors are introduced into the robots, which helps manufacture R&D and can further be used in robotics.

Conclusion

Future robots are predicted to work closely with humans in the real world and are also predicted to be more efficient than humans in certain filed. The tactical data gathered by them using tactile sensors in them help in effectively managing robotic tasks. The right integration of a tactical sensor on a robot body is a prerequisite that helps in better utilization of the determined data. Due to their contribution and benefits, tactical sensors are considered one of the practical components of robotic platforms.