发布时间 : 星期一 文章数字电子秤的设计与实现 外文文献及翻译更新完毕开始阅读73c566e13186bceb19e8bb3d
数字电子秤的设计与实现
毕业论文外文参考文献
参考一：
Abstract: In order to solve the weight problem often encountered in measuring the
low-mass objects in the trade and daily life of the modern business, the design of a new pocket-sized electronic scales. This pocket-sized electronic scales Force Sensor gravity signals into electrical signals to measure, and measuring the results of the digital display. The pocket-sized electronic scales with a small size, light weight, easy to carry, intuitive display, measurement and high precision; complex structure, the cost disadvantages. This article focuses on the load cell works, error compensation, the main parameters of selection. And the technical and economic analysis.
Keywords: pocket-sized electronic scales; weighing; sensor; error compensationCLC
1 A needs analysisIn modern commerce and trade and everyday life, often encounter the problem of measuring the weight of the low-mass objects. Although the traditional steelyard can solve this problem, but inconvenient to carry, the efficiency is not high, the display is not intuitive and low measurement accuracy; mechanical spring balance can solve this problem, but the inertia inherent low frequency, high sensitivity, measurement accuracy is not high. With the progress and update of the micro-computer technology, integrated circuit technology, sensor technology, electronic scales rapid development, it has a responsive, high accuracy, fully functional, the display is intuitive,
1
数字电子秤的设计与实现
compact, easy to use and so on.
For these reasons, in order to solve the low-mass objects weighing problem, if a small size, light weight, portable, digital display electronic scales, will be popular. Discussed below, that is, the scope of a weighing 5 kg compact electronic scales.
2 DesignThe principle of the structure of the pocket-sized electronic scales shown in Figure 1. The main task is to design compact electronic scales weighing the choice of the force sensors. Dynamometer sensor types to achieve the weighing and digital display, the key is to want to force (gravity) signals into electrical signals to measure method is mainly divided into two categories: one is the direct method, namely the use of pressure magnetic sensor, piezoelectric sensor, Piezoresistive sensors directly to the force signal converted into electrical signals; the other is the indirect method, the elastic element as the sensor will pull, pressure changes in strain, displacement, or frequency, and then strain sensors, displacement sensors, or frequency sensor strain, displacement or frequency changes for power. Comprehensive comparison of a variety of sensors, use the indirect method of strain gauge force transducer.Pocket-sized electronic scale structural principle:
Sensor → amplifier → CPU → display → AD converter
3 The working principle of the strain gauge force transducer strain gauge pasted into force, force-sensitive elastic element, the corresponding strain when the elastic element force deformation, the strain gauge into a resistance change, which led to the voltage measuring circuit changes by measuring the output voltage value, and then through the conversion can be obtained by the measurement of body weight. Since the pocket-sized electronic scales require small size, weighing in scope, precision and angle even consistency, sensor and display integration, it is selected parallel to the two holes cantilever beam strain gauge load-bearing sensor. Its characteristics are: high precision,
2
数字电子秤的设计与实现
ease of processing, simple and compact structure, strong resistance to partial load, high natural frequency.Strain gauge choice of a metal palisade metal mooring paste on the insulating substrate parked strain gages, mechanical strain resistance strain gauge feelings generally 10 - 10 - 2mm, the resistance rate of change of the attendant about 10 - 6 10 - 2 orders of magnitude, such a small change in resistance measured using the general resistance of the instrument is hard to measure out, you must use some form of measurement.
Circuit into small changes in resistance rates to changes in voltage or current, in order to secondary instrument display. Bridge measurement circuit to meet this requirement. In the load cell, R1, R2, R3, R4 strain gauge resistor bridge measurement circuit shown in Figure 3. Rm is the temperature compensation resistor, e is the excitation voltage, V is the output voltage.
参考二：
The load cell is a quality signal into a measurable electrical signal output device. Must consider the actual working environment of the sensor which sensor Yin, this is essential for the correct selection of the load cell, and it is related to the sensor can work as well as its safety and service life, and the whole weighing the reliability and safety sex. On the basic concepts and methods of evaluation of the major technical indicators of the load cell, the new and old GB qualitative differences.
The traditional concept, the load sensor weighing sensors, force sensors, collectively referred to using a single parameter to evaluate its measurement properties. Old GB will be completely different application objects and the use of environmental conditions \and \force\two sensors into one to consider, not given to
3
数字电子秤的设计与实现
distinguish between the test and evaluation methods. Old GB total of 21 indicators, were tested at room temperature; and non-linearity, hysteresis error, repeatability error, creep, the additional error of the zero temperature and the maximum error in the six indicators of the rated output additional temperature error, to determine said The level of accuracy of the weight sensor, respectively 0.02,0.03,0.05 said.
Proportion to convert the output signal can be measured. Taking into account the different place of use of the acceleration due to gravity and air buoyancy on the conversion, the main performance indicators of the load cell linearity error, hysteresis error, repeatability error, creep, zero-temperature characteristics and temperature sensitivity characteristics. In a variety of weighing and measuring the quality of the system, usually the integrated error accuracy of the integrated control sensors, and integrated error band or scale error band linked so that selection corresponds to a certain accuracy weighing weighing sensors. International Organization of Legal Metrology (OIML) requirements, sensor error with total weighing instrument error δ with Δ of 70% of the load cell linearity error, hysteresis error within the specified temperature range due to the effect of temperature on the sensitivity of the error the sum can not exceed the error band of δ. This allows the manufacturer of the components that make up the total measurement error adjustment to obtain the desired accuracy.
The load cell conversion method is divided into photoelectric, hydraulic, electromagnetic force type, capacitive, magnetic poles change the form of vibratory gyroscope ceremony, resistance strain type, to the most extensive use of resistance strain.
Electromagnetic force sensorIt
Electromagnetic force sensorIt uses a load-bearing stage load and the principle of electromagnetic force Equilibrium (Figure 5). Put the loading stage, the measured object at one end of the lever upward tilt; photoelectric detect the tilt signal, amplified into the
4