WO2021023073A1 - 一种基于多传感器的力学测量系统及其测量方法 - Google Patents

一种基于多传感器的力学测量系统及其测量方法 Download PDF

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Publication number
WO2021023073A1
WO2021023073A1 PCT/CN2020/105449 CN2020105449W WO2021023073A1 WO 2021023073 A1 WO2021023073 A1 WO 2021023073A1 CN 2020105449 W CN2020105449 W CN 2020105449W WO 2021023073 A1 WO2021023073 A1 WO 2021023073A1
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Prior art keywords
sensor
calibration
measurement
sensors
measurement system
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PCT/CN2020/105449
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English (en)
French (fr)
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白杨
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白杨
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Priority to US17/926,767 priority Critical patent/US20230194335A1/en
Publication of WO2021023073A1 publication Critical patent/WO2021023073A1/zh

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01G—WEIGHING
    • G01G23/00—Auxiliary devices for weighing apparatus
    • G01G23/01—Testing or calibrating of weighing apparatus
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01G—WEIGHING
    • G01G19/00—Weighing apparatus or methods adapted for special purposes not provided for in the preceding groups
    • G01G19/387—Weighing apparatus or methods adapted for special purposes not provided for in the preceding groups for combinatorial weighing, i.e. selecting a combination of articles whose total weight or number is closest to a desired value
    • G01G19/393—Weighing apparatus or methods adapted for special purposes not provided for in the preceding groups for combinatorial weighing, i.e. selecting a combination of articles whose total weight or number is closest to a desired value using two or more weighing units
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L25/00—Testing or calibrating of apparatus for measuring force, torque, work, mechanical power, or mechanical efficiency
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L5/00—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes
    • G01L5/0028—Force sensors associated with force applying means
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L5/00—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes
    • G01L5/16—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for measuring several components of force

Definitions

  • the invention relates to the field of mechanics measurement, in particular to a multi-sensor-based mechanics measurement system and a measurement method thereof.
  • Today's multi-sensor mechanical measurement systems generally have problems such as poor consistency, difficulty in debugging and trimming, heavy structure, poor environmental adaptability, low measurement accuracy, and limited number of sensors that can be integrated in the same system.
  • the common pressure (weighing) system has 4 sensors (mostly arranged in a four-corner "mouth” shape) and 6 sensors (more There are several modes such as the 6-point arrangement of the " ⁇ " shape) and 8 sensors (mostly the 8-point arrangement of the " ⁇ ” shape).
  • junction box also called: “hub”, “concentrator”, “accumulator”, etc.
  • AI analog input
  • ADC digital-to-analog conversion
  • Figure 1 shows a typical connection method of an existing multi-sensor mechanics measurement system, in which multiple sensors 2 are connected to a junction box 6. After the junction box 6 superimposes the analog signals input by each sensor, it is connected through an AI channel 7 It is sent to the ADC device 8 and converted into a digital signal.
  • Figure 2 takes a weighing (pressure) system (side view) using an existing multi-sensor mechanical measurement system as an example, in which multiple sensors 2 are rigidly (usually bolts) fastened to the same measuring surface (weighing)
  • the tray, etc. can also be referred to as the measuring side, or measuring end) 5 and the supporting surface (chassis, frame, etc., can also be referred to as the supporting side, or supporting end) 3.
  • Figure 3 uses the existing multi-sensor force measurement system (side view) as an example.
  • multiple sensors 2 are rigidly (usually bolts) fastened to the same measuring surface 5 (usually composed of steel cables and connecting plates/connecting plates, which can also be called measuring sides) and supporting surfaces (usually bolts). It is also composed of steel cables and connecting plates, which can also be referred to as the supporting side) 3.
  • the supporting side and the measuring side can be completely equivalent and interchangeable.
  • the measuring surface 5 in the above example is regarded as a supporting surface
  • the supporting surface 3 can also be regarded as a measuring surface.
  • the main problem of the above-mentioned structure is that the consistency of the sensor and the stress generated by the rigid connection have become important reasons that seriously affect the measurement accuracy of the weighing instrument.
  • the solid line is the "voltage-weight” calibration curve of sensor A in the example above, and the dashed line is the "voltage-weight” calibration curve of sensor B. It can be clearly seen from Figure 4 that simply accumulating the output voltages (or currents) of different sensors with inconsistent calibration curves and using them as the input value of the AI channel of the instrument will have a greater impact on the accuracy.
  • the instrument cannot know that the final value of 5.8mV at this time is 3.2mV output by the A sensor + B sensor output 2.6mV, or B sensor output 3.2mV and A sensor output 2.6mV, or A sensor output 3.0mV and B sensor output 2.8mV and other combinations.
  • This problem is called “eccentric load error”, that is, when the same object is placed in different positions of the weighing instrument, or the same force is applied to the weighing instrument at different angles and/or positions, the readings will change.
  • the current main method to solve this kind of eccentric load error problem is: add 1 or 2 adjustable resistors (potentiometers) for each sensor in the junction box, and respectively adjust the excitation (input) voltage and/or output of each sensor The voltage is adjusted.
  • this method still has the following disadvantages:
  • this method is a graph
  • the calibration curve shown in 3 adds and subtracts a constant on the X axis and Y axis respectively.
  • Figure 5 simulates an optimal adjustment result of the above example through the junction box. It can be seen that it has calibrated the deviations of the two sensors under zero and small load conditions, but their deviations under high load conditions have been amplified instead.
  • the above-mentioned multi-channel junction box that accumulates the output voltage or current after the sensors are connected in series or in parallel has the following problems:
  • mechanical sensors are generally more sensitive to external factors such as temperature, humidity, and air pressure. These external factors further increase the complexity of debugging and the overall system's ability to adapt to the above-mentioned external environmental factors.
  • the junction box serves as an additional intermediate device between the sensor and the analog-to-digital converter (ADC), which introduces an additional fault point to the entire system.
  • ADC analog-to-digital converter
  • the number of sensors is limited: because the more sensors that work together under the same system, the more difficult it is to pair, debug and other tasks (geometrically), and the overall measurement accuracy will be worse. Therefore, the number of sensors in the same measurement system is usually limited to 8 or less. This actually limits its application range in many occasions, and it is impossible to configure a suitable number of sensor matrices according to actual needs (range, area, accuracy, etc.) to meet its requirements for range, area, accuracy and other aspects.
  • the pallets, frames, chassis and other components will use the strongest possible thick steel or alloy materials. It not only wastes raw materials, but also causes problems such as heavy equipment, difficult to transport and maintain.
  • the existing multi-sensor mechanics measurement system mainly has problems such as low accuracy, high cost, heavy workload, sensitivity to the environment and location, and difficult maintenance.
  • the single-sensor measurement system has limited range, poor adaptability to actual application scenarios, and small measurement range (for example: the maximum tray area that can be measured by a single weighing/pressure sensor is usually less than 50cm x 50cm, no matter how large it is, it will easily cause problems such as excessive angle difference due to the too long moment arm) and other shortcomings.
  • the purpose of the present invention is to provide a multi-sensor mechanical measurement system with high precision, high stability, high reliability, low error, low cost, easy maintenance, low failure rate, strong environmental and position adaptability, flexible expansion, and lightweight structure.
  • a mechanical measurement system based on multiple sensors including a sensor, a digital-to-analog conversion unit, and a calculation unit;
  • the sensor includes a plurality of sensors, and each of the sensors is connected to the digital-to-analog conversion unit through its own analog input channel;
  • the digital-to-analog conversion unit converts the data and transmits it to the calculation unit;
  • the calculation unit performs a calibration on the sensor corresponding to each analog input channel according to the signal transmitted by each analog input channel, And perform a second calibration according to the results of the first calibration of all the sensors.
  • the computing unit of the present invention can be a single or any number of digital computing devices with computing capabilities, including but not limited to: computers, single-board computers, embedded industrial control devices, FPGAs, ASICs, DSP devices, etc.
  • a mechanical measurement system based on multiple sensors further comprising a support side, one end of the plurality of sensors are connected to the support side, the other end of the plurality of sensors are respectively connected to a plurality of measurement sides, and each There is no connection between the measuring sides.
  • the "support side” can be (including but not limited to) plane/curved surface (support surface/support plate/support pier), end point (support end), cable (support line/bearing cable), rod (support rod), hook (Load-bearing hook), frame, tray and other objects that can support (support) and/or fix the sensor.
  • the "measurement side” can be (including but not limited to) plane/curved surface (measurement surface/measurement plate), end point (measurement end), cable (measurement line/load-bearing cable), rod (measurement rod), hook (load-bearing hook) ), frames, trays and other objects that can help the sensor to dock and/or carry its test load.
  • a plurality of said measuring sides are connected by a connecting layer.
  • a buffer layer is provided between the connecting layer and the measurement side.
  • a measurement method of a multi-sensor-based mechanical measurement system includes the following steps:
  • Step 1 Transmit the signals of multiple sensors to the digital-to-analog conversion unit through their respective analog input channels;
  • Step 2 Perform a calibration and calibration for each of the sensors
  • Step 3 Perform secondary calibration according to the primary calibration results of all the sensors.
  • step 3 includes the following steps:
  • Step 3.1 Perform arbitrary complexity conversion processing on the output measurement value of each sensor after calibration and calibration, and use the processing result as the output value;
  • Step 3.2 superimpose the output value in step 3.1, and output the superimposed value
  • Step 3.3 Perform further processing of tare, calibration, and arbitrary complexity transformation on the superimposed value in Step 3.2, and use the processing result as the final result of the secondary calibration.
  • the present invention does not need to use a hub or similar equipment, the problems of high commissioning cost, poor accuracy, difficulty in pairing, extra noise, extra fault points, and upper limit of the number of sensors brought by the hub are completely eliminated.
  • each sensor since each sensor has its own dedicated AI channel, the system can be accurately calibrated for each sensor, thereby maintaining its precise calibration curve for each sensor, effectively preventing the superposition of different calibration curves from each other. Problems such as inaccuracy of accuracy and difficulty in configuration. In addition, problems such as difficulty in pairing sensors during equipment production and maintenance are also avoided. It also ensures that the system can perform real-time tracking and calibration of deviations caused by various internal and external factors such as temperature, humidity, air pressure, creep, condensation, dust, fatigue, etc., for each sensor, ensuring that each sensor is not only The calibration is accurate during initialization, and it can maintain its long-term stable and accurate work in subsequent use.
  • each constitutes an independent measurement unit, and independently completes the measurement (ADC, calibration, and calibration) of its own part of the component, so that its range, area and other elements can be linearly expanded
  • ADC analog to digital
  • connection layer of the present invention is a flexible element, although theoretically, stress (mainly mutual torsion) between different sensors can be generated after the connection layer is implemented, but because the stress is too weak, it can usually be ignored .
  • Fig. 1 is a schematic diagram of the structure of an existing multi-sensor mechanics measurement system.
  • Fig. 2 is a schematic structural diagram of a pressure/weighing system using an existing multi-sensor mechanical measurement system.
  • Fig. 3 is a schematic diagram of the structure of a tensile force system using an existing multi-sensor mechanical measurement system.
  • Figure 4 is the "voltage-weight" calibration curve of the two sensors in the existing multi-sensor mechanical measurement system.
  • Figure 5 is an optimized curve of "voltage-weight" calibration of two sensors in an existing multi-sensor mechanical measurement system.
  • Fig. 6 is a schematic structural diagram of a multi-sensor-based mechanical measurement system of the present invention.
  • Fig. 7 is a top view of the pressure/weighing system to which the present invention is applied.
  • Fig. 8 is a side view of Fig. 7.
  • Fig. 9 is a schematic diagram of the structure of the tension system to which the present invention is applied.
  • Fig. 10 is a schematic structural diagram of another embodiment of the tension system to which the present invention is applied.
  • Fig. 11 is a structural diagram of another embodiment of the pressure/weighing system to which the present invention is applied.
  • Fig. 12 is a schematic structural diagram of another embodiment of the pressure/weighing system to which the present invention is applied.
  • Fig. 13 is a schematic structural diagram of another embodiment of the tension system to which the present invention is applied.
  • Fig. 14 is a schematic structural diagram of another embodiment of the tension system to which the present invention is applied.
  • a multi-sensor-based mechanics measurement system including a sensor 2, a digital-to-analog conversion unit 8 and a calculation unit; the sensor 2 includes multiple, and each sensor 2 passes its own analog
  • the input channel 7 is connected to the digital-to-analog conversion unit 8; the digital-to-analog conversion unit 8 converts the data and transmits it to the calculation unit; and the calculation unit performs data transfer according to the signal transmitted by each analog input channel 7
  • the sensors 2 corresponding to each of the analog input channels 7 are calibrated once respectively, and the second calibration is performed according to the results of the first calibration of all the sensors 2.
  • the computing unit of the present invention can be a single or any number of digital computing devices with computing capabilities, including but not limited to: computers, single-board computers, embedded industrial control devices, FPGAs, ASICs, DSP devices, etc.
  • One-time calibration means that each sensor 2 has its own dedicated AI channel 7, so that the system can perform precise calibration for each sensor 2 separately, so as to maintain its precise calibration curve for each sensor 2 respectively. It effectively prevents the problems of accuracy misalignment and configuration difficulties caused by the superposition of different calibration curves. In addition, problems such as difficulty in pairing sensors during equipment production and maintenance are also avoided.
  • assigning one or more AI channels to each sensor 2 also ensures that the system can perform the temperature, humidity, air pressure, creep, condensation, dust, and fatigue for each sensor. Real-time tracking and calibration of deviations caused by various internal and external factors. It ensures that each sensor is not only calibrated accurately during initialization, but also can maintain its long-term stable and accurate work in subsequent use.
  • the process of secondary calibration can be accumulated from simple arithmetic to arbitrarily complex expressions, or arbitrarily complex arithmetic and logic operation codes.
  • the "calibration curve" in this article is a general term.
  • the actual calibration can use straight lines, piecewise functions, and curves (including but not limited to Lagrange interpolation, Newton interpolation, etc.) And other algorithms) and other methods to complete the calibration.
  • each sensor in the system is separately deployed so as not to be related (connected) to each other, and each constitutes an independent measurement unit to independently complete the measurement (ADC, calibration and calibration) of its own components. This effectively avoids the angle difference caused by the mutual stress between the sensors.
  • multiple discretely arranged measurement units do not need any additional additional mechanisms, and they can naturally work together well together.
  • a flexible or rigid connection layer can also be added between each measurement unit.
  • a pressure/weighing system including the above-mentioned multi-sensor-based mechanical measurement system, and also including a support surface (support side) 3, a plurality of the sensors 2 are set on the support On the surface (support side) 3, and each sensor 2 is respectively provided with a measurement surface (measurement side) 1, where the measurement surface (measurement side) 1 is a tray.
  • each of the trays is not connected, which ensures that the measurement surfaces (measurement sides) of each sensor 2 are independent of each other (connected), and each constitutes an independent measurement unit to independently complete the measurement of its own part of the component (ADC, calibration and calibration) work.
  • each sensor 2 is usually (respectively) fixed downward (or upward) on the supporting surface (support side) 3.
  • the supporting surface 3 can be (including but not limited to) cement/steel concrete Surface (such as cement floor, ceiling); wood surface; metal surface; composite material surface; reinforced concrete beams/piers and other supports; steel beams and keels of buildings or shelves, etc., any stable surface that can fix the sensor.
  • the sensor 2 can be carried out by (including but not limited to) bolts (screws), bayonet, welding, bonding, etc., through (including but not limited to) gaskets, angle irons, profiles and other connections and support surface 3. fixed.
  • measurement surfaces such as trays (or hooks, hanging rods) that are not related to each other are fixed to bear the actual load.
  • the sensor 2 and the measuring surface (measurement side) 1 such as the tray can also be connected and fixed in any way.
  • each sensor 2 in the system constitutes an independent single-sensor weighing unit.
  • the independence of each weighing unit should be guaranteed.
  • the tray of each sensor 2 should not be in contact with the trays of other sensors 2 (other pressure units). Between the two trays, according to the actual situation, it is usually better to be separated by 1 to 50mm.
  • the supporting surface (support side) 3 should not be too soft, causing the measuring surfaces (measurement side) such as the tray 1 (or hook) after the load to be added to contact each other due to the deformation of the supporting surface 3, and thus due to mutual contact (connection) There is coherence again. Therefore, the supporting surface 3 should still be as firm and stable as possible.
  • the present invention greatly reduces the requirements on the levelness, flatness and rigidity of the supporting surface 3.
  • the present invention can also greatly reduce the size and weight of the measurement system.
  • Traditionally in order to avoid all kinds of interfering stress between sensors as much as possible, it is necessary to ensure that components such as trays, brackets and chassis are as strong as possible (without deformation as much as possible) and kept as flat and level as possible. .
  • a pressure/weighing system with a tray area of 100x100cm (1 square meter) and a measuring range of 1000kg, its volume and weight are usually much higher than the sum of 9 trays with an area of 32x32cm and measuring units of 200kg. Even the latter has a measuring surface of at least 1 square meter and a total measuring range of 1800kg.
  • the present invention completely avoids the above-mentioned shortcomings by separating and recombining the measuring units.
  • the scalability and adaptability of the product are greatly improved: the linear expansion of elements such as measurement surface and range can be freely realized according to the actual needs of users.
  • each sensor can be connected to a measuring end (measurement side) 1 (here Each measurement side is connected by a steel cable) to form independent measurement side units. At this time, each sensor is an independent measurement unit.
  • Each measuring unit can measure its own tensile component separately in a mutually incoherent manner.
  • a plurality of said measuring sides (1) are connected by a connecting layer (5).
  • connection layer 5 can also be added between each measurement unit. As shown in Figure 11, cover the connecting layer 5 on the trays of some or all of the measurement units. For example: in a set of 9 independent measuring units with a pallet area of 32x32cm, combined in a 3x3 array to form a multi-sensor discrete matrix weighing system with a total area of 100x100cm, it is beautiful and friendly to small goods ( Seamless), protect the weighing unit and other purposes, you can deploy a connection layer for it.
  • the connecting layer 5 is a flexible element, for example, a 100 ⁇ 100 cm rubber pad (which can also be any soft material such as silica gel, textile, woven fabric, etc.) is laid on the surface of the tray 1.
  • a 100 ⁇ 100 cm rubber pad which can also be any soft material such as silica gel, textile, woven fabric, etc.
  • soft materials such as rubber and textiles deployed in a flexible way such as simple laying can theoretically generate stress (mainly mutual torsion) between different weighing units, the stress is usually negligible because it is too weak.
  • the connecting layer 5 can also be (including but not limited to) metal plates, PP plates, glass steel plates, plexiglass plates, plywood, density boards, wood boards, PC boards, PVC boards, etc.
  • the large hard cover plate can achieve the similar protection and beauty purposes as the previous article.
  • a buffer layer 4 is provided between the connecting layer 5 and the tray 1, as shown in Fig. 12.
  • the more recommended deployment method is: firstly, lay rubber rings, A buffer layer 4 of rubber pads, PVC pads, springs, hydraulic mechanisms or other soft materials, and then a whole metal plate, glass steel plate and other hard large cover plates are laid on the buffer layer 4.
  • the advantage of this is that since the tray is usually made of hard materials such as metal, the intermediate buffer layer 4 can play a role in buffering and protecting between the measuring side 1 and the connecting layer 5 such as the tray.
  • the large hard cover plate can transmit the load to each measurement unit in the system relatively more evenly.
  • Ring-shaped soft materials such as rubber rings have a better mechanical distribution for the load applied to the sensor.
  • the tray is square and the sensor is fixed in the center of the tray.
  • its longest arm distance is shortened from half of the diagonal of the square to the radius of the rubber ring.
  • a smaller force arm means a lower angle difference (this is equivalent to because its four corners have been lifted by the circular rubber pad, so the load can never be applied again To the four corners of the tray). This improves the overall accuracy of the system and also facilitates the production of independent weighing units with a larger coverage area.
  • the above principles can also be easily extended to any polygonal or other geometric shapes such as rectangles, parallelograms, ellipses, triangles, trapezoids, pentagons, hexagons, etc.
  • the overall measurement accuracy may not decrease but increase.
  • part or all of the weighing units can also be rigidly fixed.
  • this fixing method will produce strong stress between the sensors (both lever-type stress and mutual torsion stress), and these stresses It is likely to become more obvious as the system load is (unbalanced) heavier. But even in this situation, the present invention still has obvious advantages over the prior art:
  • a sandwich structure similar to the above can still be adopted, that is, a soft buffer layer 4 made of rubber and other materials is added between each measuring unit tray and the overall cover.
  • the buffer layer 4 still has the advantages of absorbing impact force and reducing the angle difference of each measurement unit. At the same time, the buffer layer can also absorb part of the stress, making the measurement results more accurate.
  • connection layer 5 in the tensile force measurement system, can also be added to multiple independent measurement systems.
  • Figure 13 shows a connection layer by adding a spring, hydraulic mechanism, etc. buffer layer 4 to each independent measuring end (measurement side), and twisting it into a loose large steel cable (flexible connection). 5. Implementation methods.
  • each measuring unit in the tensile force measurement system is respectively fixed on a steel plate in an elastic (hydraulic or spring, etc.) suspension manner to realize the flexible (spring) buffer layer 4 butting hard (Steel plate) Plan of connecting layer 5.
  • each measurement unit has N rigid fixed points connected to the same end of the N unit steel cable: rigid (fixed point) ) Butt the rigid (reinforced concrete column) connection layer; or fix the two ends of each measuring unit directly on a rubber plate (total two rubber plates, each rubber plate has N fixed points connected respectively
  • connection layer 5 when it is necessary to add the connection layer 5, if there is no clear reason, we still recommend using the flexible connection with better performance first. However, as mentioned above, even if a rigidly connected integral cover plate is used, compared with the prior art, the present invention still has significant advantages.
  • the system can be calibrated for the second time (if the connection layer is not required, this step can be skipped and the second calibration can be performed directly).
  • the secondary calibration value is obtained after the above-mentioned scaling, offset, weighted accumulation, formula transformation and other processing steps That is the 0 point weight value of the current system.
  • the superimposed value after including rubber pads, springs, steel plates, containers and other connections is the overall zero point value of the current measurement system.
  • the secondary calibration is mainly used to calibrate at the overall level of the system to eliminate the additional (non-cargo) load (tare) caused by the connecting layer and container, and to correct the rigid connecting layer and other external factors. Angle difference and other issues.
  • the secondary calibration and calibration process played an important role in the final overall accurate measurement of the system.
  • a measurement method of a multi-sensor-based mechanical measurement system includes the following steps:
  • Step 1 The signals of the multiple sensors 2 are respectively transmitted to the digital-to-analog conversion unit 8 through their respective analog input channels 7;
  • Step 2 Calibrate and calibrate each sensor 2 once;
  • Step 3 Perform secondary calibration according to the primary calibration results of all the sensors 2.
  • the secondary calibration is a process in which the output power values of each sensor after the primary calibration and calibration are input, these input values are calibrated and calibrated again, and the overall measurement result value of the system is finally output.
  • the input of the secondary calibration is the output of each sensor after the primary calibration process, and the output of the secondary calibration can be used as the overall measurement result of the system for subsequent use and processing.
  • the secondary calibration process usually includes the following steps:
  • Step 1 Perform scaling and offset processing on the output measurement value of each sensor after a calibration and calibration, and use the processing result as the current output value of the measurement unit to participate in the next calculation.
  • the above formula is just an example.
  • the measured value obtained from a calibration and calibration can be converted into an output value through any complicated -.
  • the conversion method can either be a formula like "scale factor x measured value + offset" above, or it can be a script or program of any complexity.
  • Step 2 Superimpose the output values of all measurement units in this round.
  • the "superposition” here is not limited to simple arithmetic addition, but can also (including but not limited to) be weighted accumulation, weighted sum of squares, weighted mean square sum, weighted cumulative mean square error and other forms of superposition operations.
  • you can define a weighted sum algorithm with N measurement units as follows: superimposed value weight 1 x measurement unit 1 output value + weight 2 x measurement unit 2 output value + ... + The weight N x the output value of the measurement unit N.
  • Step 3 Perform further processing such as taring, calibration, and arbitrary complexity transformation on the superimposed value generated in the second step, and use the processing result as the final result of the overall secondary calibration and calibration of the system.
  • the transformation here can either be a formula like "scale factor x measured value + offset-tare" above, or a script or program of any complexity.
  • the present invention realizes the mechanics through the hubless (junction box) design, discrete calibration and calibration, discrete arrangement, secondary calibration and calibration, and optional connection layer for each sensor independently connected to the ADC.
  • the measurement system has the advantages of high precision, high stability, high reliability, low error, low cost, easy maintenance, low failure rate, no need for pairing, strong environmental and location adaptability, light weight and compactness, and flexible expansion.

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  • General Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
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  • Force Measurement Appropriate To Specific Purposes (AREA)
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Abstract

一种基于多传感器的力学测量系统，包括传感器(2)、数模转换单元(8)以及计算单元；传感器(2)包括多个，且每个传感器(2)通过各自的模拟量输入通道(7)连接于数模转换单元(8)；数模转换单元(8)将数据转换后传输至计算单元；计算单元根据每个模拟量输入通道(7)传输的信号对每个模拟量输入通道(7)对应的传感器(8)分别进行一次标定，并根据所有传感器(8)的一次标定结果进行二次标定。该测量系统具有高精准、高稳定、高可靠、低误差、低成本、易维护、低故障率、无需配对、环境和位置适应性强、轻便小巧、扩展灵活等优势。

Description

一种基于多传感器的力学测量系统及其测量方法 技术领域
本发明涉及力学测量领域，尤其涉及一种基于多传感器的力学测量系统及其测量方法。
 背景技术
当今的多传感器力学测量系统普遍存在一致性差、调试和配平困难、结构笨重、环境适应性差、测量精度低以及同一系统中可集成的传感器数量有限等问题。
以最常见的压力（称重）系统为例，根据其量程和托盘面积等因素的不同，常见的压力（称重）系统有4传感器（多为“口”字形四角排列）、6传感器（多为“日”字形6点排列）以及8传感器（多为“目”字形8点排列）等数种模式。
其实现方式的特征为：
1.   同一系统（比如同一个地秤）内的多只传感器先通过接线盒（也叫做：“集线器”、“集中器”、“累加器”等）设备，以串联或并联的形式将其输出电压或电流累加，然后再将累加后的模拟量输出到仪器仪表设备的模拟量输入（AI）通道进行数模转换（ADC）和标定等工作。
2.   同一系统（比如同一个地秤）内的多只传感器均以刚性（螺丝、焊接、粘合等）的方式固定在同一套底盘、框架、连接器和/或托盘上。
图 1展示了一种现有多传感器力学测量系统的典型连接方式，其中多个传感器2与接线盒6相连，接线盒6将各个传感器输入的模拟信号进行叠加后，通过一路AI通道7将其输送到ADC设备8转换为数字信号。
图 2以应用现有多传感器力学测量系统的称重（压力）系统（侧视图）为例，其中多个传感器2被以刚性（通常为螺栓）的方式紧固在同一个测量面（称重托盘等，也可称为测量侧，或测量端）5和支撑面（底盘、框架等，也可称为支撑侧，或支撑端）3上。
图3以应用现有多传感器力学测量系统的拉力系统（侧视图）为例。其中多个传感器2被以刚性（通常为螺栓）的方式紧固在同一个测量面5（通常由钢缆和连接盘/连接板等部分组成，也可称为测量侧）和支撑面（通常亦由钢缆和连接盘等部分组成，也可称为支撑侧）3上。
由上例描述的拉力系统可知，其支撑侧和测量侧可以是完全对等且可互换的。例如：若将上例中的测量面5看做是支撑面的话，则其支撑面3也可被认为是测量面。
上述结构的主要问题是：传感器一致性和刚性连接所产生的应力均已成为严重影响衡器测量精度的重要原因。
业内周知，由于生产工艺等原因，即使同一批次、同一型号、相同量程的不同力学传感器之间，亦很难保证相似的一致性。
举例来说，以上述压力/称重系统为例，即使相同批次相同型号的两个8kg量程的压力/称重传感器A和B，它们的电压-重量（或电流-重量）标定曲线也可能完全不同。例如在1标准大气压、25℃、激励电压为3.3V时，传感器A加载3kg负载后的输出电压可能为3.2mV，而传感器B在相同情形下的输出电压则可能为2.6mV。上述两个传感器最终的“电压-重量”标定曲线则可能分别如图4所示。图4坐标系中的X轴表示电压，Y轴表示重量，实线为上例传感器A的“电压-重量”标定曲线，而虚线则为传感器B的“电压-重量”标定曲线。由图4可以清楚得出，将标定曲线不一致的不同传感器之输出电压（或电流）简单累加后，再作为仪器仪表AI通道的输入值，会对精度产生较大影响。
以上例来说，当AI通道的输入电压为5.8mV时，仪器无法得知此时的5.8mV最终值是由A传感器输出3.2mV + B传感器输出2.6mV得到，还是由B传感器输出3.2mV而A传感器输出2.6mV得到，亦或是A传感器输出3.0mV而B传感器输出2.8mV等其它组合得到。
由图 4可知，在上例最极端的两种情况下，若输入AI通道的5.8mV读数全部来自于传感器A，则当前负载的真实重量Ya2应为6.2kg；反之，若输入AI通道的5.8mV当前读数全部来自于传感器B，则当前负载的真实重量Yb2应为5.6kg。因此当我们仅知道传感器A和传感器B的输出叠加值为5.8mV时，我们只能大概知道其真实负载在5.6kg到6.2kg之间，这显然大大降低了称量系统的整体精度。
此问题被称为“偏载误差”，即：将相同物体放在衡器的不同位置，或将相同的力以不同的角度和/或位置施加给衡器时，其读数会发生变化。
当前解决此类偏载误差问题的主要方法为：在接线盒中为每路传感器增加1个或2个可调电阻（电位器），分别对每个传感器的激励（输入）电压和/或输出电压进行调整。然而此方法仍具有以下缺点：
此类调整的本质即近似对传感器的输入电压和/或输出电压（或电流）分别加一个固定的常量值（当然，该常量可以为负）；换句话说，该方法即为图 3所示的标定曲线分别在X轴和Y轴上加减一个常数。
很显然，这种做法仅能有限地改善其一致性，而无法真正多个传感器调整为一致。图5就模拟通过接线盒对上例所述情形的一种最优调整结果。在其中可看出，其校准了两只传感器在零点和小负载条件下的偏差，但它们在高负载条件下的偏差则反而被放大了。
退一步说，即使将复杂、非线性的标定曲线理想化为简单、线性的直线，仅仅只能在X轴和Y轴上方向上加减一个常量显然也无法拟合它们斜率不同的问题。
综合来看，上述对传感器串联或并联后，将其输出电压或电流累加的多路接线盒有如下问题：
1.   精度差：无法克服传感器标定曲线不一致带来的偏载误差问题，导致测量精度差。
2.   配对难：由于上述问题，就要求工作在同一个测量系统中的多个传感器，其标定曲线的形状要尽可能保持一致（或者在将该曲线理想化为直线时，其斜率要尽可能保持一致）。然而在现有的生产工艺中，即使是同批次同型号的不同传感器之间也很难达成这样的一致性。这就导致：
a)   配对成本高昂：往往需要大量工作才能找到大体上可配对工作的两只传感器。要对4只、8只、16只乃至更多传感器进行相互配对，则更是尤为困难。
b)   维修困难：一旦一组传感器中的一个发生了损坏，想找到与其它现有未损坏传感器配对的替换品则更加困难（通常几乎不可能）。因此大部分情况下一个传感器损坏整个测量系统即报废。
3.   调试复杂：多个传感器之间相互一致性调整复杂，往往需要逐个传感器反复进行调试。电位器的调整往往会相互影响，例如：将传感器A和B调试好后，再调试传感器A和C，则可能反过来又破坏了先前已调试完成的传感器A和B之间的一致性。因此，对接线盒电位器的调整就是一个充满了反复测试和权衡的痛苦过程。并且随着传感器数量的增多，该过程的复杂度会成几何级数暴涨。
雪上加霜的是，力学传感器普遍对温度、湿度、气压等外部因素较为敏感。这些外部因素进一步增加了调试的复杂度，以及系统整体对上述外部环境因素的适应能力。
4.   额外噪音：接线盒作为一个模拟信号的叠加和放大设备，毫无疑问会对最终送入AI通道的信号加入额外噪音，从而影响测量精度。
而电磁干扰、温度、湿度等外部环境的影响则进一步增加了其噪音的不可预测性，对系统整体工作稳定性造成负面影响。
例如：电位器、三极管、电阻、电容、电感、IC等电子器件自身的稳定性，以及它们受上述环境影响带来的扰动都会对最终输出信号造成干扰。
5.   额外故障：接线盒作为传感器和模数转换器（ADC）之间的外加中间设备，为整个系统引入了额外的故障点。
6.   传感器数量受限：由于相同系统下共同协同工作的传感器越多，其配对、调试等工作就（成几何级数地）越困难，其整体测量精度也会越差。因此同一测量系统内的传感器数量通常仅受限为8个以内。这事实上限制了其很多场合中的应用范围，无法做到按实际需求（量程、面积、精度等）配置适合数量的传感器矩阵，以适应其对量程、面积、精度等各方面的要求。
多个传感器之间通过同一底盘和/或框架和/或托盘进行刚性连接也会带来很多问题：
1.   刚性连接后的多个传感器之间需要严格配平，否则测量时会产生角差等问题。导致测量结果不准确。配平工作耗时繁琐。
2.   即使严格配平后，每次挪动位置通常都会导致误差再次产生，需要重新配平。工作量大。
3.   由于托盘、框架、底盘等构件不可能达到绝对刚体、亦难以保证绝对水平，因此传感器之间会产生杠杆（跷跷板）式或互扭式应力，导致测量结果准确性下降。
4.   为了尽可能接近刚体，托盘、框架、底盘等构件都会使用尽可能坚固的粗大钢材或合金等材料。不仅浪费原料，还导致设备笨重、难以搬运和维护等问题。
综上所述，现有多传感器力学测量系统主要有精度低、成本高、工作量大、对环境和位置敏感、维护困难等问题。
而另一方面，单传感器测量系统又有量程有限、对实际应用场景适应性差、以及测量范围小（例如：单一称重/压力传感器可测量的最大托盘面积通常小于50cm x 50cm，再大则由于力臂过长就容易引起角差过大等问题）等缺点。
 技术解决方案
本发明的目的是：提供一种高精准、高稳定、高可靠、低误差、低成本、易维护、低故障率、环境和位置适应性强、扩展灵活、结构轻巧的多传感器力学测量系统。
为了实现上述目的，本发明的技术方案是：
一种基于多传感器的力学测量系统，包括传感器、数模转换单元以及计算单元；所述传感器包括多个，且每个所述传感器通过各自的模拟量输入通道连接于所述数模转换单元；所述数模转换单元将数据转换后传输至所述计算单元；所述计算单元根据每个所述模拟量输入通道传输的信号对每个所述模拟量输入通道对应的传感器分别进行一次标定，并根据所有所述传感器的一次标定结果进行二次标定。本发明所述计算单元可以为单个或任意多个拥有计算能力的数字运算设备，包括但不限於：计算机、单板机、嵌入式工控设备、FPGA、ASIC、DSP设备等。
一种基于多传感器的力学测量系统，还包括支撑侧，多个所述传感器的一端均连接在所述支撑侧，多个所述传感器的另一端分别连接于多个测量侧，且每个所述测量侧之间不连接。
其中“支撑侧”可以是（包括但不限于）平面/曲面（支撑面/支撑板/支撑墩）、端点（支撑端）、线缆（支撑线/承重缆）、杆（支撑杆）、钩（承重钩）、框架、以及拖盘等任何可以对传感器起到支撑（支持）和/或固定作用的物体。而“测量侧”可以是（包括但不限于）平面/曲面（测量面/测量板）、端点（测量端）、线缆（测量线/承重缆）、杆（测量杆）、钩（承重钩）、框架、以及拖盘等任何可以帮助传感器对接和/或承载其测试负载的物体。
进一步的，多个所述测量侧之间通过连接层连接。
进一步的，所述连接层与测量侧之间设有缓冲层。
一种基于多传感器的力学测量系统的测量方法，包括以下步骤：
步骤1、将多个传感器的信号分别通过各自的模拟量输入通道传送至数模转换单元；
步骤2、对每个所述传感器分别进行一次标定和校准；
步骤3 、根据所有所述传感器的一次标定结果进行二次标定。
进一步的，所述步骤3中的二次标定包括以下步骤：
步骤3.1、对每个传感器经过一次标定和校准的输出测量值做任意复杂度的转换处理，并将处理结果作为输出值；
步骤3.2、对所述步骤3.1中的输出值做叠加，输出叠加值；
步骤3.3、对所述步骤3.2中的叠加值进行去皮、校准、任意复杂度变换的进一步处理，将处理结果作为二次标定的最终结果。
 有益效果
发明相对于现有技术的优势：
本发明由于不需要使用集线器或类似设备，彻底排除了集线器带来的调试成本高、精度差、配对难、额外噪音、额外故障点以及传感器数量上限等问题。
本发明由于每路传感器均拥有自己的专属AI通道，使得系统可以针对每路传感器分别进行精确标定，从而为每只传感器分别保持其精准的标定曲线，有效防止了不同标定曲线相互叠加带来的精度失准和配置困难等问题。此外，也避免了设备生产和维护等过程中的传感器配对困难等问题。也保证了系统可以为每路传感器分别进行由温度、湿度、气压、蠕变、凝露、粉尘、疲劳等各种内、外部因素引起偏差的实时跟踪和校准工作，确保了每只传感器不仅在初始化时标定准确，更在其后的使用中亦可维持其长期稳定精准工作。
本发明由于传感器之间互不相干（相连），各自组成独立的测量单元，独立完成属于自己部分的分量的测量（ADC、标定和校准）工作，使得其量程、面积等要素成为了能够线性扩展的系统特性，显著节省了材料，降低了生产成本，缩小了产品尺寸，使产品更加轻便易部署。
本发明由于其可选的连接层为柔性元件，虽然理论上在实施了连接层后也能够在不同传感器之间产生应力（主要是互扭力），但由于其应力过于微弱，因此通常可忽略不计。
 附图说明
图1是现有多传感器力学测量系统的结构示意图。
图2是应用现有多传感器力学测量系统的压力/称重系统的结构示意图。
图3是应用现有多传感器力学测量系统的拉力系统的结构示意图。
图4是现有多传感器力学测量系统中两个传感器的“电压-重量”标定曲线。
图5是现有多传感器力学测量系统中两个传感器的“电压-重量”标定优化曲线。
图6是本发明基于多传感器的力学测量系统的结构示意图。
图7是应用本发明的压力/称重系统的俯视图。
图8是图7的侧视图。
图9是应用本发明的拉力系统结构示意图。
图10是应用本发明的拉力系统的另一实施例的结构示意图。
图11是应用本发明的压力/称重系统的另一实施例的结构示意图。
图12是应用本发明的压力/称重系统的又一实施例的结构示意图。
图13是应用本发明的拉力系统的又一实施例的结构示意图。
图14是应用本发明的拉力系统的再一实施例的结构示意图。
 本发明的实施方式
以下结合附图进一步说明本发明的实施例。
请参见图6所示，一种基于多传感器的力学测量系统，包括传感器2、数模转换单元8以及计算单元；所述传感器2包括多个，且每个所述传感器2通过各自的模拟量输入通道7连接于所述数模转换单元8；所述数模转换单元8将数据转换后传输至所述计算单元；所述计算单元根据每个所述模拟量输入通道7传输的信号对每个所述模拟量输入通道7对应的传感器2分别进行一次标定，并根据所有所述传感器2的一次标定结果进行二次标定。本发明所述计算单元可以为单个或任意多个拥有计算能力的数字运算设备，包括但不限於：计算机、单板机、嵌入式工控设备、FPGA、ASIC、DSP设备等。
一次标定是指，每个传感器2均拥有自己的专属AI通道7，使得系统可以针对每个传感器2分别进行精确标定，从而为每个传感器2分别保持其精准的标定曲线。有效防止了不同标定曲线相互叠加带来的精度失准和配置困难等问题。此外，也避免了设备生产和维护等过程中的传感器配对困难等问题。
不仅如此，为每个传感器2分配一路或更多AI通道（可用于其它配套环境传感器）也保证了系统可以为每路传感器分别进行由温度、湿度、气压、蠕变、凝露、粉尘、疲劳等各种内、外部因素引起偏差的实时跟踪和校准工作。确保了每只传感器不仅在初始化时标定准确，更在其后的使用中亦可维持其长期稳定精准工作。
二次标定的过程可以从简单的算术累加到任意复杂的表达式，或任意复杂的算术和逻辑运算代码。
需要注意的是，除非进行了专门说明，否则本文中的“标定曲线”均为广义通称，实际标定时可使用直线、分段函数、曲线（包括但不限于拉格朗日插值、牛顿插值等等算法）等各种方式来完成标定。
优选的，系统中的每个传感器的测量侧各自分离部署，从而互不相干（相连），各自组成独立的测量单元，独立完成属于自己部分的分量的测量（ADC、标定和校准）工作。此举有效避免了由传感器之间相互应力产生的角差等问题。
优选的，通常来说，多个分立式排布后的测量单元，不需要任何额外附加机构，其天然地就可以很好地联合在一起共同工作。但是在一些特殊场景下，处于美观、设备保护、或者对负载友好等理由，也可以在各个测量单元之间加上柔性固定或刚性固定的连接层。
请参见图7和图8所示，一种压力/称重系统，包括上述基于多传感器的力学测量系统，还包括支撑面（支撑侧）3，多个所述传感器2均设置在所述支撑面（支撑侧）3上，且每个所述传感器2上分别设有测量面（测量侧）1，此处的测量面（测量侧）1为托盘。
优选的，每个所述托盘之间不连接,这保证了每个传感器2的测量面（测量侧）互不相干（相连），各自组成独立的测量单元，独立完成属于自己部分的分量的测量（ADC、标定和校准）工作。
对于压力/称重系统来说，每个传感器2通常分别（各自）向下（或向上）固定在支撑面（支撑侧）3上，支撑面3可以（包括但不限于）是水泥/钢混面（例如水泥地板、天花板）；木材面；金属面；复合材料面；钢筋混凝土梁/墩等支撑物；建筑或货架的钢梁、龙骨等可固定传感器的任何稳定面。
传感器2可通过（包括但不限于）螺栓（螺丝）、卡口、焊接、粘合等各种方式，通过（包括但不限于）垫片、角铁、型材等任意连接件与支撑面3进行固定。
而在传感器的上面（或下面）则各自分别固定有互不相关的托盘（或挂钩、挂杆）等用于承载实际负载的分立测量面（测量侧）。传感器2与托盘等测量面（测量侧）1之间同样可以使用任意方式进行连接和固定。
这样，系统中的每个传感器2就各自组成了一个独立的单传感器称量单元。为了保证其工作中的独立性，各个称量单元之间应该保证无关性。具体来说，对于使用托盘的压力/称重单元来说，每个传感器2的托盘都不应该与其它传感器2（其它压力单元）的托盘发生接触。两个托盘之间，根据实际情况，通常以相隔1至50mm间距为佳。
而由于托盘1等测量面（测量侧）之间相互无相干（不相连），因此即使所有传感器2均被固定在同一个支撑面3上，并明确该支撑面3并不满足绝对刚体和绝对水平和绝对平整等要求，也不会影响每个压力/称重单元各自的测量精度。这是因为它们之间互相无关，故不会由于负载或其它原因而产生如前文所述的杠杆（跷跷板）、互扭等各类应力。因此大大提升了总体测量精度。
不过显而易见，支撑面（支撑侧）3也不能过于柔软，导致加入负载后的托盘1（或挂钩）等测量面（测量侧）由于支撑面3的变形而相互接触，从而由于相互接触（相连）又产生了相干性。因此，支撑面3仍应当尽可能地牢固和稳定。但很明显，本发明对支撑面3的水平度、平整度以及刚性等要求都大大降低了。
因此除了上述优势以外，本发明还可以大大降低测量系统的尺寸和重量。传统上，想要尽可能避免传感器之间产生各种相互干扰的应力就必须尽可能保证托盘、支架和底盘等构件有尽可能强的刚性（尽可能不发生形变）并尽可能保持平整和水平。很显然，对于量程越高、托盘（压力面）面积越大的压力/称重系统来说，要达到上述刚性和平整度的要求就越困难（势必要使用更厚实坚固的材料）。因此现有压力/称重系统通常随着其量程、托盘面积等性能增的加，其产品的重量、体积等参数会成几何级数增长。
例如：一个托盘面积100x100cm（1平米），量程1000kg的压力/称重系统，其体积和重量通常远远高于9个托盘面积32x32cm，量程200kg的测量单元之和。即使后者在组合后也有至少1平米的测量面以及1800kg的总量程。
而本发明通过将测量单元分立后再次组合的方式，完全避免了上述缺点。使得量程、面积等要素成为了能够线性扩展的系统特性。即：测量系统中每增加一倍的量程和/或面积，最多只会使系统增加相同比例（一倍）的体积及重量，而不会使其提及和/或重量成几何级数（指数级）的方式增长。这不但显著节省了材料，降低了生产成本，缩小了产品尺寸。同时还极大提升了产品可扩展性和适应性：可以根据用户实际需求，自由实现测量面和量程等要素的线性扩展。
请参见图9所示，在一个由N个传感器（当然也有至少N个AI通道）组成的多传感器拉力测量系统中，可以将每个传感器分别与一个测量端（测量侧）1（此处的每个测量侧为一根钢索）相连，从而组成各自独立的测量侧单元。此时每只传感器即为一个独立测量单元。每个测量单元均可以相互无相干的方式分别测量自己的拉力分量。
请参见图10 所示，由于前文所述案例（请参考图 3及其相关的背景说明）中拉力测量系统支撑端（支撑侧）与测量端（测量侧）的对等特性，我们完全可以将支撑侧也替换为各自独立的钢缆等连接装置。此时每只传感器仍然为各自独立测量单元。每个测量单元仍可以相互无相干的方式分别测量自己的拉力分量。并且此时拉力测量系统中的支撑端（支撑侧）3与测量端（测量侧）1之间，又恢复了对等性。
优选的，多个所述测量侧（1）之间通过连接层（5）连接。
通常来说，每个传感器2形成独立的测量单元后，不需要任何额外附加机构，其天然地就可以很好地联合在一起共同工作。但是在一些特殊场景下，出于美观、设备保护、或者对负载友好等理由，也可以在各个测量单元之间加上连接层5。请参见图11所示，在部分或所有测量单元的托盘上覆盖连接层5。例如：在一套由9个托盘面积为32x32cm的独立测量单元，以3x3阵列的形式组合而成总面积为100x100cm的多传感器分立式矩阵称量系统中，出于美观、对细小货物友好（无缝）、保护称量单元等目的，可以为其部署连接层。优选的，连接层5为柔性元件，例如在托盘1面上铺设一张100x100cm的橡胶垫（也可以是硅胶、纺织品、编织物等任何软质材料）。以简单铺设等柔性方式部署的橡胶、纺织品等软质材料虽然理论上也能够在不同称量单元之间产生应力（主要是互扭力），但由于其应力过于微弱，因此通常可忽略不计。
类似地，连接层5除了上述软质材料外，还可以（包括但不限于）是金属板、PP板、玻璃钢板、有机玻璃版、胶合板、密度板、木板、PC板、PVC板等各类硬质大盖板，从而达到与前文相似的保护、美观等目的。优选的，连接层5与托盘1之间设有缓冲层4，请参见图12所示，更推荐的部署方式是：首先为每个独立测量单元的测量侧（托盘等）分别铺设橡胶圈、橡胶垫、PVC垫、弹簧、液压机构或其它软质材料的缓冲层4，再在该缓冲层4上铺设整张的金属板、玻璃钢版等硬质大盖板。这样做的好处在于由于托盘通常也是由金属等硬质材料制作，中间的缓冲层4可以在托盘等测量侧1和连接层5之间起到缓冲和保护等作用。
此外，这种三明治型的部署方式还有两个额外的好处：
1.   （上例中的100x100cm）大硬质盖板可以将负载相对更均匀地传递给系统中的各个测量单元。
2.   橡胶圈等圆环状的软质材料对负载施加给传感器的力来说，有更优的力学分布。将环状橡胶垫圈放置在方形测量单元托盘上后，假设该托盘为正方形，并且传感器被固定在该托盘中心。那么该测量单元在承受负载时，其最长的力臂距离就从正方形对角线的一半缩短为了橡胶圈的半径。我们知道对于单传感器系统来说，更小的力臂就意味着更低的角差（这就相当于因为其四个角都已被圆形橡胶垫抬空，因此负载永远不可能再被施加到该托盘的四个角上了）。这就提高了系统的整体精度，同时也有利于制作覆盖面积更大的独立称量单元。显而易见，除了正方形以外，上述原理也可以简单地推广到任意矩形、平行四边形、椭圆形、三角形、梯形、五边形、六边形等各种多边形或其它几何形状上。
综上所述，为测量系统整体添加一个三明治型的柔性连接层后，虽然有可能在传感器间引入微小的相互应力，但可获得美观、无缝（对细小货物友好）、耐用、易维护等优势，甚至由于每个称量单元角差的减少（最大力臂缩短），其整体测量精度还可能不降反升。
当然，在某些特殊的应用场合中，也可以对部分或全部称量单元进行刚性固定。例如：以焊接、螺丝等固定手段，将一张100x100cm的钢板与上例中的9个测量单元一一紧固。很显然，若无法保证良好的刚性、水平度和平整度，那么这种固定方式将在传感器之间产生出较强的应力（既有杠杆式应力，又有互扭式应力），而且这些应力很可能随着系统负载被（不均衡地）加重而越发明显。但即使在这种场合中，本发明仍然比现有技术仍然有着明显的优势：
1.   避免了精度差、配对难、调试复杂、额外噪音、额外故障、传感器数量受限等所有由集线器带来的弊端。
2.   即使刚性固定的盖板会带来应力和角差，通过纯数字化的软件系统（而不是通过接线盒中的电位器）来执行校准也更简单方便。
进一步地，即使使用了刚性连接，仍然可采用与前文类似的三明治结构，即：在各个测量单元托盘与整体盖板之间加入一层由橡胶等材料构成的软质缓冲层4。该缓冲层4仍然有吸收冲击力、以及降低每个测量单元单体角差等优势。与此同时，缓冲层还可以吸收部分应力，使得测量结果更为准确。
请参见图13所示，在拉力测量系统中也可以为多个独立测量系统添加软质或硬质的柔性或刚性连接层5。例如：图 13即展示了一种通过将每根独立测量端（测量侧）添加弹簧、液压机构等缓冲层4，并将其拧合成一根松散的大钢缆（柔性连接）来作为连接层5的实现方式。
请参见图14所示，将拉力测量系统中每根测量单元的两端分别各自以弹性（液压或弹簧等等）悬挂的方式固定在一块钢板上，实现柔性（弹簧）缓冲层4对接硬质（钢板）连接层5的方案。
又或将每根测量单元的两端各自固定在对应的同一根钢筋混凝土立柱上（共两根立柱，每根立柱上有N个刚性固定点连接N个单元同一端的钢索：刚性（固定点）对接硬质（钢筋混凝土立柱）连接层；亦或将每根测量单元的两端分别各自直接固定在一块橡胶板上（共两块橡胶板，每块橡胶板上有N个固定点分别连接N个单元同一端的钢索：刚性（固定点）对接软质（橡胶板）连接层等各种手段来实施软质/硬质材质以及柔性/刚性连接的各种排列组合。
当然，在有必要加入连接层5时，如无明确的理由，我们仍然推荐优先使用表现更佳的柔性连接。但是正如前文所述，即使采用了刚性连接的整体盖板，与现有技术相比，本发明仍具有显著优势。
当所有测量单元上的柔性或刚性连接层5实施完成后，即可对该系统进行整体二次标定（若无需实施连接层，也可跳过该步骤直接进行二次标定）。此时，在成功部署了橡胶垫、弹簧、钢板、容器（篮筐等）等非货品负载后，再经过上述缩放、偏移、加权累加、公式变换等处理步骤后得出的二次标定值即为当前系统的0点重量值。换句话说，包含了橡胶垫、弹簧、钢板、容器等连接物后的叠加值，即为当前测量系统的整体0点值。
确定0点值后，我们还可以通过不断添加砝码等方式来确定系统整体的标定曲线。若使用了刚性连接层的话，可能还需要对各个测量单元的缩放因子、偏移量、权重等参数进行自动或手动的微调，以消除角差。相反，若使用了柔性连接池或未使用连接层，则通常无需进行类似的微调即可实现很高的精度和很小的误差。当然，在诸如缺乏足够稳固的支撑面、支撑面过于崎岖、测量面倾角较大等外部条件十分恶劣的情况下，有时即使未使用刚性连接层，可能偶尔也需要使用上述参数对部分测量单元进行微调。
可以看出，二次标定主要用于在系统整体层面上进行标定，消除连接层和容器所带来的额外（非货物）负载（去皮），同时修正刚性连接层等其它外部因素带来的角差等问题。二次标定和校准过程对系统最终的整体准确测量起到了不可忽略的重要作用。
一种基于多传感器的力学测量系统的测量方法，包括以下步骤：
步骤1、将多个传感器2的信号分别通过各自的模拟量输入通道7传送至数模转换单元8；
步骤2、对每个所述传感器2分别进行一次标定和校准；
步骤3 根据所有所述传感器2的一次标定结果进行二次标定。
与一次标定过程不同，二次标定是以经过一次标定和校准后的各个传感器输出力量值为输入，对这些输入值进行再次标定和校准，最终输出系统整体测量结果值的过程。
换句话说，二次标定的输入是各个传感器经过一次标定过程后的输出，而二次标定的输出则可作为系统整体的测量结果，供后续使用和处理。
二次标定过程通常包含如下步骤：
步骤1.  对每个传感器经过一次标定和校准的输出测量值做缩放和偏移等处理，并将处理结果作为该测量单元的本次输出值，参与下一步计算。例如：可以对每个测量单元的力量值进行如“输出值 = 缩放因子 x 测量值 + 偏移量”的转换，其中“缩放因子”和“偏移量”均为可配置项，由系统自动配置或管理员手动配置。当然，以上公式只是一个例子，在实际使用过程中，从一次标定和校准得出的测量值可以通过任意复杂的-转换为输出值。转换的方式既可以如前文“缩放因子 x 测量值 + 偏移量”这样的公式，也可以是一段任意复杂度的脚本或程序。
步骤2.  对本轮所有测量单元的输出值做叠加。此处“叠加”并不仅限于简单的算术加法，还可以（包括但不限于）是加权累加、加权平方和、加权均方和、加权累计均方差等各种形式的叠加操作。例如：可定义一种包含N个测量单元的加权求和算法如下：叠加值 = 权重1 x 测量单元1输出值 + 权重2 x 测量单元2输出值 + ... + 权重N x 测量单元N输出值。
步骤3.  对第二步生成的叠加值进行去皮、校准、任意复杂度变换等进一步处理，将处理结果作为系统整体二次标定和校准的最终结果。此处的变换既可以如前文“缩放因子 x 测量值 + 偏移量 – 皮重”这样的公式，也可以是一段任意复杂度的脚本或程序。
容易看出，在本发明中，无论每个传感器是使用分立固定，还是柔性连接面或刚性连接面来连接，其二次校准过程、作用和注意事项均类似，其主要作用是：
1.   通过合理的方式将各个测量单元的输出值以某种形式叠加。
2.   消除和校准由“进行独立排布”和“实施连接层”等各个过程中引入的额外应力、误差、不平衡、配重、以及非正常负载（连接层、容器等）等其它因素而产生的测量结果偏差。
综上所述，本发明通过每传感器独立接入ADC的无集线器（接线盒）设计、分立标定和校准、分立式排布、二次标定和校准，以及可选的连接层，实现了力学测量系统高精准、高稳定、高可靠、低误差、低成本、易维护、低故障率、无需配对、环境和位置适应性强、轻便小巧、扩展灵活的优势。
需要指出的是，虽然本发明的实施例仅针对压力/称重和拉力测量系统，但其原理和思想显然也同样适用于剪切力、旋转力、水平力、摩擦力、支撑力、负载力等各种其它力学测量系统。在包括但不限于上述各类力学测量系统中使用本发明所述的方法的，均属于本发明保护范围。

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  1. 一种基于多传感器的力学测量系统，其特征在于：包括传感器（2）、数模转换单元（8）以及计算单元；所述传感器（2）包括多个，且每个所述传感器（2）通过各自的模拟量输入通道（7）连接于所述数模转换单元（8）；所述数模转换单元（8）将数据转换后传输至所述计算单元；所述计算单元根据每个所述模拟量输入通道（7）传输的信号对每个所述模拟量输入通道（7）对应的传感器（2）分别进行一次标定，并根据所有所述传感器（2）的一次标定结果进行二次标定。
  2. 根据权利要求1所述的基于多传感器的力学测量系统，其特征在于：还包括支撑侧（3），多个所述传感器（2）的一端均连接在所述支撑侧（3），多个所述传感器（2）的另一端分别连接于多个测量侧（1），且每个所述测量侧（1）之间不连接。
  3. 根据权利要求2所述的基于多传感器的力学测量系统系统，其特征在于：多个所述测量侧（1）之间通过连接层（5）连接。
  4. 根据权利要求3所述的基于多传感器的力学测量系统，其特征在于：所述连接层（5）与测量侧（1）之间设有缓冲层（4）。
  5. 一种基于多传感器的力学测量系统的测量方法，其特征在于：包括以下步骤：
    步骤1、将多个传感器（2）的信号分别通过各自的模拟量输入通道（7）传送至数模转换单元（8）；
    步骤2、对每个所述传感器（2）分别进行一次标定和校准；
    步骤3 、根据所有所述传感器（2）的一次标定结果进行二次标定。
  6. 根据权利要求5所述的测量方法，其特征在于：所述步骤3中的二次标定包括以下步骤：
    步骤3.1、对每个传感器（2）经过一次标定和校准的输出测量值做任意复杂度的转换处理，并将处理结果作为输出值；
    步骤3.2、对所述步骤3.1中的输出值做叠加，输出叠加值；
    步骤3.3、对所述步骤3.2中的叠加值进行去皮、校准、任意复杂度变换的进一步处理，将处理结果作为二次标定的最终结果。
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