Comments: Sensor technology commonly used in robotics
If a person senses information from the outside through five senses, then the robot is the information received from the outside world through the information collected by the sensor . The sensor can be said to be a common and important device, which is the feeling Specified measurement of the various quantities and according to certain rules will be converted into useful signals for the device or device. For the sensor, the input can be divided into static and dynamic according to the input state. We can get the static characteristics of the sensor based on the relationship between the output and the input based on the steady state of each value. For example, blood pressure measurement is the most common type of medical measurement. Our usual blood pressure measurements are indirect measurements of blood pressure in the vessel by measuring the relationship between blood flow and pressure on the body surface. The sensors needed to measure blood pressure usually include a flexible diaphragm that converts the pressure signal into a distorted diaphragm that is then converted into a corresponding electrical signal based on the strain or displacement of the diaphragm. We can detect the systolic pressure at the peak of the electrical signal. After passing through the inverter and the peak detector, we can get the diastolic pressure by the shape of the sensor. We can get the average pressure through the integrator. Machinery Brackets ,Metal Brackets ,Metal Shelf Brackets,Steel Brackets Ningbo Metal Sharing Supply Chain Management Co., Ltd , https://www.metalsharing.com
The main indicators of the static characteristics of the sensor linearity, hysteresis, repeatability, sensitivity and accuracy. The dynamic characteristics of a sensor refer to the response characteristics of the input over time. Dynamic characteristics are usually described using a model of automatic control such as transfer function. Normally, the signals received by the sensor have a weak low-frequency signal, and the external interference can sometimes exceed the measured signal amplitude. Therefore, eliminating the noise of the serial input becomes a key sensor technology.
Physical sensor
Physical sensors are sensors that detect physical quantities. It is the use of certain physical effects, the measured physical volume into a form of energy to facilitate the processing of the signal device. The output signal and the input signal have a definite relationship. The main physical sensors photoelectric sensors, piezoelectric sensors, piezoresistive sensors, electromagnetic sensors, pyroelectric sensors, optical fiber sensors.
As an example, let us look at the more common photoelectric sensor. This sensor converts optical signals into electrical signals, which directly detect the radiation information from the object, and can also convert other physical quantities into optical signals. The main principle is the photoelectric effect: When the light shines on the material, the electrical effect of the material changes, where the electrical effects include electron emission, conductivity and potential current.
Obviously, a device that can easily produce such an effect becomes a major component of a photoelectric sensor, such as a photoresistor. In this way, we know that the main working process of a photoelectric sensor is to accept the corresponding light irradiation, and convert the light energy into electricity through a device like a photo resistor, and then obtain the required output by amplification and denoising electric signal. Here the output electrical signal and the original optical signal has a certain relationship, usually close to the linear relationship, so the calculation of the original optical signal is not very complicated. The principles of other physical sensors can be analogized to photoelectric sensors.
The application of physical sensors is very wide range, we only biomedical point of view of the application of physical sensors, then it is not difficult to speculate that physical sensors in other aspects also have important applications.
Let's take another look at the breath measurement technique. Respiratory measurement is an important basis for clinical diagnosis of pulmonary function, both in surgery and patient monitoring are essential. For example, when using a thermistor sensor for measuring respiratory rate, mount the sensor's resistance on the outside of the front end of a clip, clip the clip over the nose, and pass the heat as the flow of breathing gas flows from the thermistor surface Sensitive resistance to measure the frequency of breathing and the status of hot gas.
Another example of the most common body surface temperature measurement process, although it seems easy, but it has a complex measurement mechanism. Body surface temperature is determined by local blood flow, the thermal conductivity of the underlying tissue and the heat dissipation of the epidermis and many other factors, so measuring the skin temperature to take into account many aspects. Thermocouple sensors are more commonly used in the measurement of temperature, usually rod-shaped thermocouple sensors and thin-film thermocouple sensors.
Because the size of the thermocouple is very small and the accuracy is relatively high, it is possible to measure the temperature at a certain point accurately. With the help of later analysis statistics, a more comprehensive analysis result can be obtained. This is incomparable with the traditional mercury thermometer, but also shows the broad prospects for the application of new technologies to the scientific development.
As can be seen from the above description, only in biomedical, physical sensors have a wide range of applications. Sensor development is multi-functional, image, intelligent sensors. Sensor measurement as an important means of data acquisition is indispensable for industrial production and even family life, and physical sensors are the most common family of sensors. The flexible use of physical sensors will inevitably create more products and better benefits .
Fiber Optic Sensor
In recent years, the sensor is moving in a sensitive, precise, adaptable, compact and intelligent direction. In the process, fiber optic sensors are a new addition to the sensor family. Optical fiber has many excellent properties such as: anti-electromagnetic interference and atomic radiation performance, diameter fine, soft, light weight mechanical properties, insulation, non-responsive electrical properties, water, heat and corrosion resistance of chemical properties, It can reach people's eyes and ears in unattainable places (such as high temperature areas), or in areas harmful to humans (such as nuclear radiation area), but also can transcend human physiological boundaries and receive sensory organs Unforeseen outside information.
Optical fiber sensor is a new technology emerging in recent years and can be used to measure a variety of physical quantities such as sound field, electric field, pressure, temperature, angular velocity, acceleration, etc. It can also accomplish the measurement tasks that are difficult to accomplish with existing measurement techniques. In tight spaces, fiber optic sensors show unique capabilities in environments with strong electromagnetic interference and high voltage. Currently there are more than 70 kinds of optical fiber sensors, which are roughly divided into optical fiber sensors and optical fiber sensors.
The so-called optical fiber sensor itself is the optical fiber directly to receive the outside world was measured. The external measured physical quantity can cause the length, refractive index and diameter of the measuring arm to change, so that the light transmitted within the fiber changes in amplitude, phase, frequency, polarization and the like. The light transmitted by the measuring arm interferes (compares) with the reference light of the reference arm to change the phase (or amplitude) of the output light, and the change in the measured light can be detected based on this change. The sensitivity of the transmitted phase in the fiber to the outside world is high, and the physical quantity corresponding to the small phase change of the negative quadratic radian of 10 can be detected using the interference technique. The use of optical fiber winding and low loss, can be a long fiber optic disc into a small diameter optical fiber ring in order to increase the use of length, to obtain higher sensitivity.
Optical fiber sensor is a kind of sensor using optical fiber itself. When the fiber is a little tiny external force, it will produce micro-bending, and its light transmission capacity has undergone great changes. Sound is a kind of mechanical wave. Its effect on the optical fiber is to stress and bend the optical fiber. By bending it, the strength of the sound can be obtained. Compared with laser gyro, FOG has high sensitivity, small size and low cost. It can be used in high performance inertial navigation system of aircraft, ships and missiles. Figure is the principle of the optical fiber sensor turbine flow meter .
Another major category of fiber optic sensors is the use of fiber optic sensors. Its structure is as follows