CN106404130A - Weighing sensor assembly and weighing method - Google Patents

Abstract

The invention provides a weighing sensor assembly and a weighing method. The weighing sensor comprises an upper load bearing surface; a lower load bearing surface opposite to the upper load bearing surface; an elastic element having a center shaft, an included angle formed between the center shaft and a gravitational acceleration direction being an angle of inclination of the elastic element; a primary strain unit for measuring a first deformation amount of the elastic element for obtaining a weighing output; a secondary strain unit being at a first angle to the center shaft for measuring a second deformation amount of the elastic element, the first angle being obtained by setting the angle of inclination and the second deformation amount of the elastic element to meet a monotonic function relationship; and a calculation unit for calculating a weighing error based on the second deformation amount and using the weighing error for correcting the weighting output. The invention can compensate for the real-time error of the weighing output.

Description

Weighing and sensing device assembly and Weighing method

Technical field

The present invention relates to a kind of weighing and sensing device assembly of achievable error compensation and its Weighing method.

Background technology

LOAD CELLS is a kind of primary element of Measuring Object weight, it by certain method, by measured object Weight conversion be flexible member deformation, then by the deformation of flexible member be converted into the signal of telecommunication be identified survey Amount, to obtain the weight being weighed object.

Column type sensor is a kind of widely used version, wherein column type sensor in LOAD CELLS It is most widely used with shaking column type sensor again.Relatively other sensor construction forms have the advantage of uniqueness, example As simple and compact for structure, elastic element rigidity is big, dynamic response is fast, anti-overload ability is strong etc., therefore by widely It is applied to the people's livelihood and industrial circle, such as platform scale, wagon balance etc..

Taking the application of wagon balance as a example, a chassis will install 6 to 8 LOAD CELLSs, even more many.For Ensure the degree of accuracy weighed, each LOAD CELLS be required for adjusting setting angle when installing it is ensured that It keeps state of vertically weighing in weighing process.But, in actual application, wagon balance is through multiple Weigh, rock and lateral impact, LOAD CELLS understands situations such as run-off the straight, rotation unavoidably.In addition, by It is all to use in outdoor environment in wagon balance, be inevitably subject to the shadow of day and night temperature and the Various Seasonal temperature difference Ring, the effect of the temperature difference makes weighing platform produce expansion or contraction distortion, and this also makes sensor run-off the straight and rotation Situations such as.

When sensor is in and tilts the state weighing, when the distribution of force opposed vertical in its flexible member weighs Can occur significantly to change, this allows for weighing identical object, after inclination, sensor exports during opposed vertical There is larger error in sensor output.Further, since sensor, when manufacturing, inevitably exists Fabrication error, such as machining error, paster error etc., even if the presence of these errors can make sensor perpendicular Directly weigh under state, when sensor rotates, the output of sensor also can change.

In order to eliminate error present in the above-mentioned practical application in sensor, many people have done various researchs, But all do not obtain substantial progress.

In patent CN 101441102A and patent CN 101672689A, by setting angle in sensor Sensor, the angle theta between measurement sensor axis direction and acceleration of gravity direction, i.e. the inclination angle of sensor Degree, then by output Wr during sensor perturbations divided by the cosine value cos θ at angle of inclination, that is, is revised Sensor output afterwards.But, the feasible of this compensation method must is fulfilled for following two premises:First, sensing The output error curve that device tilts to any direction is identical, and the design yet with sensor is simultaneously non-fully right Claim, the inclined output curve of error of therefore sensor different directions is different in fact；Second, between sensor not There is individual difference, that is, have ignored the impact of the various fabrication error such as machining, but actually these errors are all It is inevitable.

In patent US 20040251059A1, paste special answering by four planes in post and beam sensor Become piece, carry out error compensation using special bridge, but this is only a cancellation the techniques such as machining, paster by mistake The impact of difference, the system-level output error that sensor perturbations are caused is helpless.

In addition, existing various compensation method is substantially for special sensor construction form, for example square Cut section bar, because existing sensor construction form is varied, therefore these compensation methodes just do not have universal The suitability.

Content of the invention

In order to eliminate the weighing system that LOAD CELLS is caused in actual applications due to inclination and the rotation of sensor Weighing error, the present invention proposes a kind of achievable real-time error compensation and can improve the weighing and sensing of certainty of measurement Device assembly and Weighing method.

According to an aspect of the present invention, a kind of weighing and sensing device assembly, upper pressure-bearing surface are provided；

Lower pressure-bearing surface is relative with described upper pressure-bearing surface；

Flexible member, has central shaft, between described upper pressure-bearing surface and lower pressure-bearing surface, described central shaft with Angle between acceleration of gravity direction is the angle of inclination of flexible member；

Principal strain unit, is arranged in the strain region of described flexible member, and described principal strain unit measurement is described First deformation quantity of flexible member, described first deformation quantity is weighed output for acquisition；

Secondary strain unit, is arranged in the strain region of described flexible member, described time strain unit with described in Heart axle becomes first angle, and described strain unit measures the second deformation quantity of described flexible member, described first angle It is to meet monotonic functional relationship by second deformation quantity at the described angle of inclination of setting and flexible member to obtain；

Computing unit, described computing unit is used for calculating weighting error according to the second deformation quantity and weighing described Error is modified to output of weighing.

Preferably, meet quadratic function relation between described weighting error and the second deformation quantity.

Preferably, described principal strain unit at least includes two principal strain elements, two described principal strain element phases To the both sides being arranged on described flexible member.

Preferably, described strain unit is arranged at least two nonparallel planes of described flexible member, Each plane, at least provided with one strain gauge element, is respectively used to measure the first compensation deformation quantity of described flexible member Compensate deformation quantity with second, described second deformation quantity includes described first and compensates deformation quantity and described second compensation deformation Amount.

Preferably, described strain gauge element includes becoming the 3rd resistor wire grid of described first angle with described central shaft.

Preferably, when needing the angle of inclination carrying out error compensation to be -5 ° to 5 °, described first angle is 5 ° to 85 °.

According to another aspect of the invention, a kind of Weighing method is also provided, for described LOAD CELLS, wraps Include：

Gather described first deformation quantity of described principal strain unit output；

Described second deformation quantity of described strain unit output of collection；

Weigh according to described first deformation quantity calculates output；

Described weighting error is calculated according to described second deformation quantity；And

Weigh according to described weighting error correction output.

Preferably, calculate described weighting error according to described second deformation quantity to include：

Equivalent angle of inclination is calculated according to described second deformation quantity；And described title is calculated according to equivalent angle of inclination Weight error.

Preferably, in two nonparallel planes that described time strain unit includes be arranged on described flexible member At least two strain gauge elements, for sensing the first compensation deformation quantity and the second compensation deformation of described flexible member Amount, described equivalent angle of inclination includes corresponding to the described first the first offset angle compensating deformation quantity and corresponds to Second offset angle of described second compensation deformation quantity, wherein,

Described second angle is calculated according to equation below：

Wherein, β₁For described first offset angle, β₂For described second offset angle；k₁、k₂、c₁、c₂For normal Number；ε₁For the described first compensation deformation quantity, ε₂For the described second compensation deformation quantity.

Preferably, described weighting error is calculated according to equation below：

Wherein, Δ span is described weighting error；A, b, c, d, e and f are compensating parameter；β₁For described One offset angle；β₂For described second offset angle.

Preferably, meet quadratic function relation between described weighting error and the second deformation quantity.

The present invention passes through using above-mentioned technical scheme, can improve the application post such as platform scale, wagon balance weighing device The certainty of measurement of the equipment of formula LOAD CELLS, eliminates sensor perturbations in application process or rotates the weighing causing Error.

It should be appreciated that the general description more than present invention and the following detailed description are all exemplary and illustrative , and it is intended that the present invention as claimed in claim provides further explanation.

Brief description

It is that they are included and constitute of the application in order to provide further understanding of the invention including accompanying drawing Point, accompanying drawing shows embodiments of the invention, and plays the effect explaining the principle of the invention together with this specification. In accompanying drawing：

Fig. 1 is the structural representation of LOAD CELLS during the vertical state according to the embodiment of the present invention.

Fig. 2 is the structural representation of LOAD CELLS during the heeling condition according to the embodiment of the present invention.

Fig. 3 is the Section A-A sectional view of the LOAD CELLS shown in Fig. 1.

Fig. 4 is the section B-B sectional view of the LOAD CELLS shown in Fig. 1.

Fig. 5 is the schematic diagram of the weighing device according to the embodiment of the present invention.

Fig. 6 is the schematic diagram of weighing device according to the embodiment of the present invention state of weighing when weighing vehicle.

Specific embodiment

Now with detailed reference to Description of Drawings embodiments of the invention.

Referring to figs. 1 to Fig. 4, the LOAD CELLS 1 that the present invention provides is preferably column weighting sensor, has Shake pole structure.LOAD CELLS 1 includes pressure-bearing surface 2, flexible member 3, lower pressure-bearing surface 4, principal strain list First and secondary strain unit.Lower pressure-bearing surface 4 is relative with upper pressure-bearing surface 2.Flexible member 3 has central shaft 31, its Between upper pressure-bearing surface 2 and lower pressure-bearing surface 4.The upper pressure-bearing surface 2 of LOAD CELLS 1 and lower pressure-bearing surface 4 are respectively There is a contact site contacting with flexible member 36, the machining accuracy of its position and flexible member 3, inclination Angle and Probe-radius are relevant.This contact site 6 is a contact point in an ideal case, but in actual applications, Position due to contact can occur slight deformation, so being generally a contact surface.

With reference to Fig. 1 it is assumed that flexible member 3 is processed ideally, when LOAD CELLS 1 is vertically weighed, The line of upper and lower two contact sites (i.e. contact point) 6 is overlapped with the central shaft 31 of flexible member 3.With reference to Fig. 2, When LOAD CELLS 1 tilts and weighs, the line of upper and lower two contact points 6 and the central shaft 31 of flexible member 3 Misaligned and become inclination angle beta.The cross sectional shape of flexible member 3 can be Arbitrary Shape Cross Section, such as circular section, Square section or H-shaped section etc..

Principal strain unit and secondary strain unit are arranged in the strain region 5 of flexible member 3.Specifically, main Strain unit at least includes two principal strain elements 7, and two principal strain elements 7 are oppositely arranged on flexible member 3 Both sides (as shown in Figure 3).In the present embodiment, principal strain element 7 is resistance strain plate, and it is used for measuring bullet First deformation quantity of property element.Principal strain element 7 includes first resistor wire grid 71 and second resistance wire grid 72.The One electrical resistance wire grid 71 is parallel with central shaft 31, for sensing flexible member 3 along longitudinal shape in central shaft 31 direction Variable.Second resistance wire grid 72 is vertical with central shaft 31, for sensing the transverse deformation amount of flexible member 3.Vertical Weigh output to deformation quantity and transverse deformation amount for calculating.

Secondary strain unit is separately positioned at least two nonparallel planes of flexible member 3, and each plane is extremely One strain gauge element 8 of setting less.In certain embodiments, secondary strain unit includes four strain gauge elements 8, As shown in Figure 4.Wherein, a pair two-by-two of four time strain gauge elements 8, put down for four that are separately positioned on flexible member 3 On face.In the present embodiment, secondary strain gauge element 8 is also resistance strain plate, and secondary strain gauge element 8 includes 3rd resistor Wire grid 81.3rd resistor wire grid 81 first angle α become with central shaft 31.Two pairs strain gauge elements 8 are respectively For measuring the second deformation quantity of described flexible member 3, described second deformation quantity includes the first compensation deformation quantity and Two compensation deformation quantities.Preferably, the inclination angle beta of LOAD CELLS 1 is less than or equal to 5 °, secondary strain gauge element 8 It is 5 ° to 85 ° with first angle α formed by central shaft 31.

Fig. 5 is the schematic diagram of the weighing device according to the embodiment of the present invention.With reference to Fig. 5, what the present invention provided weighs Sensor (LOAD CELLS as shown in Figures 1 to 4) can be applicable on weighing device 9, and weighing device 9 is by many Individual LOAD CELLS 1 and weighing platform 10 form.As described in the embodiment, weighing device 9 includes 6 biographies of weighing Sensor 1.In some change case, weighing device 9 can include at least one LOAD CELLS 1.Weighing and sensing Device 1 preferably, is column weighting sensor, and has and shake pole structure.In other embodiments it is also possible to For cutting column type sensor.

Fig. 6 is the schematic diagram of weighing device 9 according to the embodiment of the present invention state of weighing when weighing vehicle. As shown in fig. 6, weighing device can be a kind of wagon balance weighing device, vehicle to be weighed is placed in weighing platform 10 On.

The present invention also provides a kind of weighing technique, comprises the steps：

1) the first deformation quantity of collection principal strain unit output.First deformation quantity is according to the first of principal strain element 7 The longitudinal deformation amount of electrical resistance wire grid 71 and second resistance wire grid 72 measurement and transverse deformation amount obtain.

2) gather the second deformation quantity of time strain gauge element 8 output in time strain unit.

3) according to the first deformation quantity, obtain output of weighing.Preferably, the first deformation quantity can after being converted into the signal of telecommunication As output of weighing.

4) described weighting error is calculated according to the second deformation quantity.

In one embodiment, the equivalent angle of inclination of LOAD CELLS 1 is calculated first according to the second deformation quantity.? Ideally, when the spherical radius of the upper and lower end parts of flexible member 3 is identical, equivalent angle of inclination is inclination angle Degree, is line and the central shaft 31 angulation β of two contact points 6.But in practice, weighting error is not It is only used for compensating and tilts the error causing, and the error that rotation causes can be compensated.The error that rotation produces is main Fabrication error from the production process of sensor.Rotate the error causing also to produce on compensating plate accordingly Output, when carrying out Error Calculation, does not make a distinction or the error that rotation causes, therefore at this time Output on item 8 foil gauge not only includes tilting but also includes rotating the error causing, and at this time calculates Angle of inclination be referred to as equivalent angle of inclination.Due to secondary strain gauge element 8 and first angle formed by central shaft 31 α is to meet monotonic functional relationship by the second deformation quantity of the described inclination angle beta of setting and flexible member to obtain , therefore first angle α can not take 0 ° and 90 °.Because when first angle α is 0 ° and 90 °, tilting Angle beta is quadratic function relation with the second deformation quantity of flexible member.Specifically, the inclination of LOAD CELLS 1 Angle beta is less than or equal to 5 °, and secondary strain gauge element 8 and first angle α formed by central shaft 31 are 5 ° to 85 ° When, the inclination angle beta of LOAD CELLS 1 can approximate processing be linear relationship with the output of time strain gauge element 8, etc. Effect angle of inclination can be calculated by equation below：

Wherein, β₁For the first offset angle of LOAD CELLS 1, β₂The second compensation angle for LOAD CELLS 1 Degree.In the present embodiment, β is line and central shaft 31 angulation of two contact points 6, β₁And β₂ It is the angle component towards two non-flat line directions, in the case of preferably, β₁And β₂It is towards two orthogonal directions Angle component；K, c are a constant, with secondary strain gauge element 8 and first angle α, elasticity formed by central shaft 31 Poisson's ratio of element 3 material etc. is relevant.For example, when flexible member 3 material is steel, and angle [alpha] is 61.3 °, K is ± 65.8, c=0；ε is time the second deformation quantity of strain gauge element 8 output, ε₁And ε₂It is the first compensation respectively Deformation quantity and the second compensation deformation quantity.

In the present embodiment, k1, k2, c1, c2 can be determined by theoretical or test calibration method.

1), theoretical method

When flexible member processing, paster ideally, elastomer element material is steel and first angle is 61.3 ° when, k1=k2=65.8；C1=c2=0.When first angle is -61.3 °, k1=k2=-65.8；C1=c2=0.

2), test calibration method

Flexible member applies demarcate load, can be the half of rated load.

Along the first offset angle direction inclination angle beta 11, measurement the first offset angle ε 11 now；Along first Offset angle direction inclination angle beta 12, measurement the first offset angle ε 12 now.

In the same manner, k2 and c2 can be obtained in aforementioned manners.

Afterwards, weighting error is calculated according to the equivalent inclination angle beta of LOAD CELLS 1.Specifically, pass through The theory function relation of classical mechanics is modified, obtains can be used for real-time error compensation in actual weighing process Functional relationship between weighting error and the first offset angle and the second offset angle：

Wherein, Δ span is weighting error；A, b, c, d, e and f are compensating parameter；β 1, β 2 be two to First offset angle of secondary strain gauge element 8 output of 31 one-tenth first angles α of central shaft and the second offset angle.

In the present embodiment, a, b, c, d, e and f can obtain in the following way：Flexible member is applied Mark-on determines load W, can be the half of rated load.

Tilt flexible member along any direction, measurement weigh output Wbridge1, β 11, β 12 now, Δ Span1=(Wbridge1-W)/W in the same manner, along any direction tilt flexible member certain angle can get Δ span 2, β21、β22；Δspan 3、β31、β32；Δspan 4、β41、β42；Δspan 5、β51、β 52；Δspan 6、β61、β62.Above-mentioned data is substituted in equation, as follows：

Above-mentioned equation can be represented with matrix form, as follows

Therefore, compensating parameter a～f can be calculated according to following formula.

5) weighed output according to weighting error correction.Specifically, according to following formula, output of weighing is modified.

Wherein, Δ span is weighting error；W_bridgeFor the not compensated output of weighing of sensor；W_compFor compensating Sensor afterwards is weighed output.

Signal of telecommunication conversion, collection and calculating in above-mentioned steps, is preferably processed by a digit chip.

In one embodiment, carry out in weighing process in wagon balance weighing device 9, when LOAD CELLS 1 When run-off the straight or rotation, now the stress of flexible member 3 there occurs change with respect to preferable vertical state. The secondary strain gauge element 8 of both direction produces output ε₁And ε₂, the digit chip of LOAD CELLS 1 is according to time strain The both direction output of element 8, can get the weighting error of LOAD CELLS 1 now, and according to weighting error Actual weight output is modified, you can the output of weighing of the LOAD CELLS 1 after being compensated.After compensation The output of weighing of LOAD CELLS 1 not only eliminates the systemic weighing error that causes, also eliminates by weighing The flexible member 3 of sensor 1 angular errors caused by fabrication error in process of production.

Those skilled in the art can be obvious, the above-mentioned example embodiment of the present invention can be carried out various modification and Modification is without departing from the spirit and scope of the present invention.Accordingly, it is intended to make the present invention cover will in appended right Ask the modifications of the present invention in the range of book and its equivalent arrangements and modification.

Claims (11)

1. a kind of weighing and sensing device assembly is it is characterised in that include：

Upper pressure-bearing surface；

Lower pressure-bearing surface is relative with described upper pressure-bearing surface；

Flexible member, has central shaft, between described upper pressure-bearing surface and lower pressure-bearing surface, described central shaft with Angle between acceleration of gravity direction is the angle of inclination of flexible member；

Principal strain unit, is arranged in the strain region of described flexible member, and described principal strain unit is used for measuring First deformation quantity of described flexible member, described first deformation quantity is weighed output for acquisition；

Secondary strain unit, is arranged in the strain region of described flexible member, described time strain unit with described in Heart axle becomes first angle, and described strain unit is used for measuring the second deformation quantity of described flexible member, and described first Angle is to meet monotonic functional relationship by second deformation quantity at the described angle of inclination of setting and flexible member to obtain 's；

Computing unit, described computing unit is used for calculating weighting error according to the second deformation quantity and weighing described Error is used for output of weighing is modified.

2. weighing and sensing device assembly as claimed in claim 1 is it is characterised in that described weighting error and second Quadratic function relation is met between deformation quantity.

3. weighing and sensing device assembly as claimed in claim 1 or 2 is it is characterised in that described principal strain unit At least include two principal strain elements, two described principal strain elements are oppositely arranged on the both sides of described flexible member.

4. weighing and sensing device assembly as claimed in claim 1 or 2 is it is characterised in that described time strains unit It is arranged at least two nonparallel planes of described flexible member, each plane is at least provided with one strain elements Part, is respectively used to measure the first compensation deformation quantity of described flexible member and the second compensation deformation quantity.

5. weighing and sensing device assembly as claimed in claim 4 is it is characterised in that described strain gauge element includes Become the 3rd resistor wire grid of described first angle with described central shaft.

6. weighing and sensing device assembly as claimed in claim 1 needs to carry out error compensation it is characterised in that working as Angle of inclination be -5 ° to 5 ° when, described first angle be 5 ° to 85 °.

7. a kind of Weighing method, for the weighing and sensing device assembly described in claim 1 it is characterised in that wrapping Include：

Gather described first deformation quantity of described principal strain unit output；

Described second deformation quantity of described strain unit output of collection；

Weigh according to described first deformation quantity calculates output；

Described weighting error is calculated according to described second deformation quantity；And

Weigh according to described weighting error correction output.

8. Weighing method as claimed in claim 7 is it is characterised in that calculate institute according to described second deformation quantity State weighting error to include：

Equivalent angle of inclination is calculated according to described second deformation quantity；And described title is calculated according to equivalent angle of inclination Weight error.

9. Weighing method as claimed in claim 8 is it is characterised in that described strain unit includes being arranged on At least two strain gauge elements in two nonparallel planes of described flexible member, for measuring described elasticity unit First compensation deformation quantity of part and the second compensation deformation quantity, described equivalent angle of inclination is included corresponding to the described first benefit Repay the first offset angle and second offset angle corresponding to described second compensation deformation quantity of deformation quantity, wherein,

Described equivalent angle of inclination is calculated according to equation below： $\left\{\begin{array}{c}{\mathrm{\β}}_1=k_1{\mathrm{\ϵ}}_1+{\mathrm{\ϵ}}_1\\ {\mathrm{\β}}_2=k_2{\mathrm{\ϵ}}_2+{\mathrm{\ϵ}}_2\end{array}\right.,$

Wherein, β₁For described first offset angle, β₂For described second offset angle；k₁、k₂、c₁、c₂For normal Number；ε₁For the described first compensation deformation quantity, ε₂For the described second compensation deformation quantity.

10. Weighing method as claimed in claim 9 is it is characterised in that weigh according to equation below calculates Error： $\mathrm{\Δ}span=a+{\mathrm{b\β}}_1+{\mathrm{c\β}}_2+{\mathrm{d\β}}_1^2+{\mathrm{e\β}}_1{\mathrm{\β}}_2+{\mathrm{f\β}}_2^2,$

Wherein, Δ span is described weighting error；A, b, c, d, e and f are compensating parameter；β₁For described One offset angle；β₂For described second offset angle.

11. Weighing methods as claimed in claim 7 are it is characterised in that described weighting error and the second deformation quantity Between meet quadratic function relation.