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Robot’s Sensors and Instrumentation
Published in Jitendra R. Raol, Ajith K. Gopal, Mobile Intelligent Autonomous Systems, 2016
When physical contact is made with an object, the sensor senses this. An example of touch sensor is a simple micro-switch that either turns on or off as contact is made. A force sensor is also used as a touch sensor which not only detects the presence of a contact but also senses the amount of pressure/force applied on it. A collection of touch sensors which provides information about the contact and about the size of an object in contact is called a tactile sensor. All displacement sensors like micro-switches, LVDTs, pressure sensors and magnetic sensors can be used as touch sensors.
Sensors: Touch, Force, and Torque
Published in Richard L. Shell, Ernest L. Hall, Handbook of Industrial Automation, 2000
To date it is apparent that microengineering has been applied most successfully to sensors. Some sensor applications take advantage of the device-to-device or batch-to-batch repeatability of wafer-scale processing to remove expensive calibration procedures. Current applications are restricted largely to pressure and acceleration sensors, though these in principle can be used as force sensors. As the structure is very delicate, there are still problems in developing a suitable tactile sensor for industrial applications [21].
Robot Tactile Sensing: Skinlike and Intrinsic Approach
Published in Spyros G. Tzafestas, Intelligent Robotic Systems, 2020
Antonio Bicchi, Giorgio Buttazzo
By the term “tactile sensor” we mean in general a device capable of collecting information about contact phenomena occurring between the robot end-effector (usually on parts called fingertips) and the surroundings. Although the important role of tactile sensing is almost unaminously recognized in robotics, the characteristics that a tactile sensor should have are not equally clear. Specific features a tactile sensor should be sensitive to are not definable a priori but strongly depend on the task the robot is intended to perform and on the type of end-effector with which the robot is equipped. Nevertheless, it is possible to identify some types of information that a tactile sensing system should provide to allow the hand to perform fine manipulation tasks: Force information: Sensing the intensity and direction of both forces and torques exerted through contact between the end-effector and the manipulated object is instrumental to any fine manipulation operation. To measure the friction component of contact force may also be very important to prevent slippage of objects held by the hand.Synthetic geometric information: The position of the contact area on the fingertips and the direction of the common normal vector to the contacting surfaces represent essential information for manipulation control and can also be very useful for object recognition.Local geometric features: Information about the extension, shape, and indentation profile of the contact area allows the extraction of small (compared to fingertip dimensions) features of the explored surface, such as edges, vertices, and cavities.Texture, friction, and thermal properties: Other peculiar characteristics of the explored surface can be sensed by touch, such as its superficial roughness, friction, temperature, or thermal conductivity.
Recent advances in neuromorphic transistors for artificial perception applications
Published in Science and Technology of Advanced Materials, 2023
As shown in Figure 12(a), Kim et al. [79] demonstrated a biorealistic tactile sensor system. The artificial tactile sensing system is composed of tactile sensors, voltage-controlled oscillator (VCO) circuits, neuron carbon nanotube (CNT) transistors and CNT synaptic transistor arrays, acting as the sensing receptors, action potentials, neurons and synaptic networks in biological system, respectively. Interestingly, the semivolatile transistor can switch the operation mode based on the bias conditions. Thus, a single device type is allowed to play two different roles (neuronal and synaptic functions) simultaneously. The tactile sensor converts pressure stimuli into resistance changes. In addition, the tactile sensor system can distinguish temporally correlated pressure stimuli, so as to realize pattern recognition (Figure 12(b,c)). In a 10 × 10 CNT transistor array, one CNT transistor acted as neuronal device that operated in volatile mode. Other 10 × 4 CNT transistors operated in a nonvolatile mode acted as a synaptic network to classify the pattern of input pressure. Besides, the learning and recognition process of biological real perception is demonstrated. It is worth noting that the recognition accuracy can be improved through an iterative learning process, which is highly similar to the biological perception learning process.
A piezoresistive dual-tip stiffness tactile sensor for mango ripeness assessment
Published in Cogent Engineering, 2022
Chiebuka T. Christopher, Ahmed M. R. Fath Elbab, Christian O. Osueke, Bernard W. Ikua, Daniel N. Sila, Ahmed Fouly
Thus, little work has been recorded in the application of tactile sensor on fruit sorting and ripeness detection based on the fruit stiffness as a function of its elastic modulus. Sensors that have been employed by many researchers in stiffness sensing of objects are tactile sensors. Tactile sensors have a variety of industrial applications, including robotics (Suwanratchatamanee et al., 2010, 2011), haptic devices (Peterlík & Filipovic, 2011), biomedical sensing (Aoyagi & Yoshida, 2004) and polymer characterization (Sanchez et al., 2008). According to Lee and Nicholls (1999), a tactile sensor is a device or system that can characterize mechanical properties of the targeted object or of the contact between the sensor and the object. Tactile sensors for contact force measurement have been well documented, and a number of prototype sensors have been developed (Cecchi et al., 2015; Tsuji et al., 2009).