Vibration Measurement

What is a tactile sensor? and what are its types

What is a tactile sensor and what is meant by a tactile sensor

A tactile sensor can measure any physical interaction with its environment. This sensor is capable to measure the parameters related to the contact of the sensor with an object. These sensors are designed according to the biological sense of cutaneous touch, which is able to detect the stimuli from mechanical stimulation, temperature, and pain. A tactile sensor will receive and respond to a signal and this signal could be a force or a physical contact

Basically a tactile sensor is a touch sensor that can provide information about the object which in contact with it. The information about the object could be the shape, size, and type of material. Tactile sensors are able to detect the pressure in mobile phones finger-TPS is used to sense the force applied by the human hand.

What are the applications and uses of a tactile sensor

Tactile sensors have the ability to detect certain things such as the presence of an object. It can also determine the part shape, location, and direction. The object which is in contact with the sensor, contact is pressure so pressure distribution can be determined. The inspection of the object can be done with the help of this device such as texture monitoring, joint checking, or damage detection can also be done. Tactile sensors are capable to detect a wide range of stimuli it can detect the object presence and it is able to get a tactile image too. A tactile sensor has a lot of sensitive sites and with the help of these the tactile sensor is capable to measure more than one property.

Tactile sensors are used in robotics, computer hardware, and security systems a major application of the tactile sensor is in the touchscreen of the mobile phones and in computers. Elevator button is also an example of a tactile sensor, tactile imaging is used for medical imaging purposes. Tactile sensors can also be used for vibration sensing. Tactile sensors can also be used as a pressure-sensitive device they have pressure-sensitive films by which the pressure can be determined.

What are the required characteristics of a tactile sensor for industrial applications

It should be a single point contact, but the sensing area could be of any size if the size of the sensor is small then it can be easily used in many places. The sensitivity of this sensor is depended on a various physical characteristic, the physical barrier between the sensor and object would be a problem. For most industrial applications if the sensor has the range from 0.4-10N with the allowance for accidental mechanical overload is satisfactory. Minimum bandwidth of the sensor should be 100 Hz. The characteristics of the sensor should be stable and repeatable with low hysteresis. This sensor will be used for industrial applications so it must be robust and protected from environmental damage.

What are the major components of a tactile sensor

  • Touch surface
  • Transduction medium
  • Structure
  • Control interface

What are the types of tactile sensor

There are many types of tactile sensors like optical, piezoelectric, resistive, capacitive, magnetic and strain gauge.

Optical tactile sensor

Optical tactile sensors are of two types intrinsic and extrinsic, in this type the intensity of the light is modulated by moving an obstruction into the light path. It has certain advantages like immunity to electromagnetic interference and has a very high resolution. Low cabling is required and processing electronics can be remote from the sensor.

Piezoelectric tactile sensor

The effect of generating a voltage across a sensing element when pressure is applied to it is the piezoelectric effect. The generation of voltage is proportional to the applied pressure. In this, there won’t be any need for an external sensor. The advantages of this type of sensor are durability and wide dynamic range. Measurement of pressure can be done.

Resistive tactile sensor

The working of this sensor is based on the change in electrical resistance between the conductor polymer and the electrodes. This type of tactile sensor is widely used. When the pressure has applied the resistance of the conductive material would change. Then the resistance would be measured. The advantages of this sensor are of high durability and good overload tolerance.

Capacitive tactile sensor

In a capacitive sensor, the change of capacitance between two electrodes is used. This type of capacitive sensor will measure the capacitance and it will vary under applied pressure. The capacitance of the parallel plate capacitor is related to the separation of the plate and their area. The capacitance will vary according to the load. The advantage of this type of sensor is a linear response and wide dynamic range.

Magnetic tactile sensor

The magnetic tactile sensor uses two methods, one is a change of flux density is measured using magneto-resistive devices and the other method is the change of magnetic coupling between windings deformation of the magnetoelastic core. The advantages of this sensor are of high sensitivity and no mechanical hysteresis.


post-graduate in Electronics & communication.

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