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Selection of Sensors, Transducers, and Actuators
Published in Wasim Ahmed Khan, Ghulam Abbas, Khalid Rahman, Ghulam Hussain, Cedric Aimal Edwin, Functional Reverse Engineering of Machine Tools, 2019
Memoon Sajid, Jahan Zeb Gul, Kyung Hyun Choi
There are two basic types of inductive sensors: one in which the inductance of the sensors changes in response to the input stimulus and second in which induction is used as a coupling mechanism to sense the stimulus [38,39]. Pressure and displacement sensors usually lie in the first category in which the spacing between the turns is changed in response to an external pressure that can result in change of inductance. The second type of inductive sensor is mostly used in electrical measurements and most commonly in current measurement. Inductors can pick up an electrical signal or a flowing current without even physical contact through a phenomenon known as electromagnetic induction. They are thus preferred as sensing elements in delicate and sensitive systems where the sensors should be physically isolated from the circuit loop.
Dimensional Metrology
Published in Richard Leach, Stuart T. Smith, Basics of Precision Engineering, 2017
Massimiliano Ferrucci, Han Haitjema, Richard Leach
Inductive sensors operate on the principle of inductance, that is the capacity of electrical currents to be induced in the presence of a changing magnetic field. Inductive displacement measuring devices generate alternating magnetic fields by driving an alternating current through a coil located at the end of the probe. The magnetic fields penetrate the measured object and within it induce small looping electric currents, known as eddy currents. These currents produce magnetic fields that oppose the original magnetic field and effect a change in the impedance of the probe coil. By measuring this change in the coil’s inductance, the distance of the object from the probe can be determined. The response of the target to the original magnetic field varies with its material. Therefore, measurements from inductive sensors should be specifically calibrated for the material of the measured object.
Sensors and Grippers in Robot Work Cells
Published in Ulrich Rembold, Robot Technology and Applications, 2020
An inductive sensor is based on the change of induction due to the motion of a metallic object in a magnetic field. If a metallic object is brought into a magnetic field, energy is drained from the oscillator, which results in damping. The functional relationship between the distance to be measured and the magnitude of damping created is unfortunately nonlinear. Figure 5.14 shows the schematic diagram of an inductive sensor. If the sensor works as a proximity switch, a defined signal is produced by a comparator circuit.
Development of contact displacement sensor based on frequency-modulated continuous-wave
Published in Journal of Modern Optics, 2020
Bin Sun, Gang Zheng, Xiongxing Zhang, Lang Bai
Linear Variable Differential Transformer (LVDT) inductive sensor, pneumatic sensor, grating displacement sensor, Hall displacement sensor, laser triangulation and other displacement sensors can transform the geometric quantity variation into different voltages with displacement through different physical media to realize the measurement of the length. The inductive displacement sensor is in close contact with the object surface through the probe and the movement of the probe drives the change of the inductance of the coil on the measuring rod. By analysing the inductance voltage signal, the accurate measurement of the contour of the object can be accurately realized, and thus it is widely used in the field of equipment manufacturing. Because of its convenient installation, simple and reliable structure, and low environmental requirements, the inductive sensor is widely used in the field of precision measurement, which plays a key role in the processing and manufacturing of parts and the reliable operation of industrial automation. However, there are certain measurement errors in the measurement principle of the inductive sensor, it is difficult to ensure high precision and consistency in coil winding and parts processing. Therefore, it is impossible to solve the common problems, such as small range, low precision, large drift and poor stability. Take the Swiss TESA axial inductance sensor GT61 as an example, as shown in Figure 3, the maximum measurement range is 10 mm (−5 mm to +5 mm), and the highest measurement accuracy is only 20 μm (≥0.20%), so it is difficult to guarantee the micron or sub-micron level of measurement requirements of large-size parts.