CN202270028U - Micro skeleton two-dimensional force sensor and skeleton two-dimensional force sensing device - Google Patents

Abstract

The utility model discloses a micro skeleton two-dimensional force sensor and a skeleton two-dimensional force sensing device. The two-dimensional force sensor comprises a mechanical sensitive element, a hard centre, a strain gauge and a measurement circuit. The mechanical sensitive element is used for completing the measurement on a skeleton two-dimensional force, namely realizing the measurement on axial tension and a radial shear force. The hard centre is positioned in the centre of the mechanical sensitive element for bearing and transmitting an external force. The strain gauge is attached to the upper surface of the mechanical sensitive element. The measurement circuit converts and amplifies a signal. The skeleton two-dimensional force sensor provided by the utility model can realize the measurement on the axial tension and the radial shear force on the fracture trauma section by matching an external skeletal fixation device. The mechanical sensitive element has an E-type circular diaphragm structure, and has the advantages of small size, high sensitivity and good linearity. The mechanical sensitive element adopting the above simple structure can particularly be molded into one piece at one time, thus is good in rigidity, low in cost and good in dynamic performance.

Description

A kind of miniature skeleton 2 D force sensor, skeleton two dimension Force sensor

Technical field

This utility model belongs to sensor technical field, relates to a kind of skeleton two dimension Force sensor, relates in particular to a kind of miniature skeleton 2 D force sensor.

Background technology

Stress intensity on the skeleton trauma section directly influences the speed and the quality of bone healing; When the stress on the skeleton trauma section is excessive; Will cause skeleton trauma section osteocyte downright bad, fracture delayed union, not even healing; Stress is too little, and the wound section does not reach the certain stress stimulation level and the effect of held stationary.At present; Being used to fracture the holder of various structures of clinical treatment both at home and abroad can be to the fracture end application of force; But the size and Orientation for the power that puts on the trauma fracture section all can't be known; Only with the sensation of operative doctor, this blindness pressuring method is conspicuous to the healing rate of fracture and the negative effect of quality.To thoroughly change the present situation of blindly pressurizeing in the fractures, improve the speed and the quality of union of fracture, must solve this bottleneck problem of sensing detection of live body skeleton trauma section stress.

Aspect the skeleton stress measurement, the Li Mengyuan of Luoyang Polytechnical College has designed S type pick off, has realized the measurement of mean stress size on the skeleton trauma section has been obtained some achievements in research, and the fracture clinical treatment is had certain directive function.But this S type sensor bulk and weight are bigger, and can only realize the measurement of one-dimensional power (axial force), can't measure the radial component on the skeleton trauma section.And the existence of radial component is totally unfavorable to union of fracture, and it can destroy bone bridge overlap joint and plastotype reparation on the wound section, and fracture delayed union is not even healed, and must eliminate.In addition, present existing force measuring sensors product all can't be applied to the measurement of skeleton trauma section stress, and most important reason is following: the one, and volume is big, causes shared space bigger, clinical operation operation inconvenience, even can't operate; The 2nd, the unprotect device makes that the reliability of sensing detection is not high, is difficult to adapt to clinical medical specific (special) requirements; The 3rd, weight is big, is not easy to patient's activity.Therefore, a kind of microsensor that can be used to measure skeleton trauma section stress of design has important significance for theories and practical value.

The utility model content

This utility model technical problem to be solved is: a kind of miniature skeleton 2 D force sensor is provided, can realizes the 2 D force sensor to skeleton trauma section axial push-pull power and the measurement of radial shear power.

In addition, this utility model also provides a kind of skeleton two dimension Force sensor, can realize the 2 D force sensor to skeleton trauma section axial push-pull power and the measurement of radial shear power.

For solving the problems of the technologies described above, this utility model adopts following technical scheme:

A kind of miniature skeleton 2 D force sensor, said 2 D force sensor comprises: mechanics sensing element, hard center, foil gauge, measuring circuit;

Said mechanics sensing element is promptly realized axial pressure and radial shear force measurement in order to accomplish skeleton two dimension force measurement;

The said center that is centered close to the mechanics sensing element firmly is used for bearing and transmitting external force;

Said foil gauge is attached to the upper surface of mechanics sensing element;

Said measuring circuit is accomplished conversion and the amplification to signal, and measuring circuit is fixed on the interior intracavity of mechanics sensing element lower surface.

As a kind of preferred version of this utility model, said mechanics sensing element adopts E type diaphragm slice structure.

As a kind of preferred version of this utility model, said 2 D force sensor comprises the chassis, plays the fixation of sensor effect.

As a kind of preferred version of this utility model, said 2 D force sensor comprises two groups of foil gauges, and on the circumference that a group is distributed in the mechanics sensing element, another group is attached on 45 ° of directions of mechanics sensing element.

As a kind of preferred version of this utility model, said 2 D force sensor comprises 8 foil gauge R ₁, R ₂, R ₃, R ₄, R ₅, R ₆, R ₇, R ₈

Become characteristic according to the mechanics sensing element in the axial symmetry characteristic and the symmetry of the rotary-inversion axis under the effect of radial shear power of the effect of axial push-pull power, with foil gauge R ₅, R ₆, R ₇, R ₈Be evenly distributed on the circumference of mechanics sensing element R ₁, R ₂, R ₃, R ₄Be attached on 45 ° of directions of mechanics sensing element;

Wherein, R ₁, R ₂, R ₃, R ₄Be used for realizing the measurement to axial pressure, R ₅, R ₆, R ₇, R ₈Be used for realizing to the radially measurement of shearing force; 4 foil gauges are formed equiarm full bridge measurement circuit, and this group of bridge mode can realize the static decoupling to two-dimentional power.

As a kind of preferred version of this utility model,, set up the mechanical model of the mechanics sensing element of skeleton 2 D force sensor under axial push-pull power and the effect of radial shear power according to plate theory; Solve the analytic solutions of the radial strain of axial push-pull power and radial shear power according to mechanical model; And try to achieve the strain analytic solutions under the force action by principle of stacking, prove that theoretically the mechanics sensing element can be used for axial pressure and radial shear force measurement.

A kind of skeleton two dimension Force sensor, said Force sensor comprises: miniature skeleton 2 D force sensor, bone external fixator, boosting-rod;

Said mechanics sensing element is promptly realized axial pressure and radial shear force measurement in order to accomplish skeleton two dimension force measurement;

The said center that is centered close to the mechanics sensing element firmly is used for bearing and transmitting external force;

Said foil gauge is attached to the upper surface of mechanics sensing element;

Said measuring circuit is accomplished conversion and the amplification to signal, and measuring circuit is fixed on the interior intracavity of mechanics sensing element lower surface;

The skeleton 2 D force sensor is connected in the bone external fixator, and hard center is connected through screw thread with boosting-rod, acts on force measurement on the skeleton trauma section and accomplishes the two-dimentional mechanical axis of skeleton to pressure and radial shear force measurement through boosting-rod is applied to.

As a kind of preferred version of this utility model, said mechanics sensing element adopts E type diaphragm slice structure; Said 2 D force sensor comprises the chassis, plays the fixation of sensor effect.

As a kind of preferred version of this utility model, said 2 D force sensor comprises two groups of foil gauges, and on the circumference that a group is distributed in the mechanics sensing element, another group is attached on 45 ° of directions of mechanics sensing element.

As a kind of preferred version of this utility model, said 2 D force sensor comprises 8 foil gauge R ₁, R ₂, R ₃, R ₄, R ₅, R ₆, R ₇, R ₈

Become characteristic according to the mechanics sensing element in the axial symmetry characteristic and the symmetry of the rotary-inversion axis under the effect of radial shear power of the effect of axial push-pull power, with foil gauge R ₅, R ₆, R ₇, R ₈Be evenly distributed on the circumference of mechanics sensing element R ₁, R ₂, R ₃, R ₄Be attached on 45 ° of directions of mechanics sensing element;

Wherein, R ₁, R ₂, R ₃, R ₄Be used for realizing the measurement to axial pressure, R ₅, R ₆, R ₇, R ₈Be used for realizing to the radially measurement of shearing force; 4 foil gauges are formed equiarm full bridge measurement circuit, and this group of bridge mode can realize the static decoupling to two-dimentional power.

The beneficial effect of this utility model is: in the miniature skeleton 2 D force sensor that this utility model proposes; Force sensing element adopts E type diaphragm slice structure; Has the advantage that size is little, highly sensitive, the linearity is good; Especially the force sensing element of this simple structure taked of this utility model can be used as an one piece machine-shaping, make the good rigidity of this utility model, cost is low, dynamic property good.The skeleton 2 D force sensor that this utility model designed can cooperate the bone external fixator to realize trauma fracture section axial push-pull power and radial shear force measurement.

Description of drawings

Fig. 1-1, Fig. 1-2 are the structural representation of miniature skeleton 2 D force sensor.

Fig. 2-1, Fig. 2-2, Fig. 2-3 are the paster of miniature skeleton 2 D force sensor foil gauge and the structural representation of group bridge.

Fig. 3-1, Fig. 3-2 are the physical dimension figure of miniature skeleton 2 D force sensor.

Fig. 4 is the use sketch map that miniature skeleton 2 D force sensor is measured skeleton power.

Note is following among the figure:

1, mechanics sensing element; 2, hard center;

3, chassis; 4, foil gauge;

5, measuring circuit; 6, bone external fixator.

The specific embodiment

Specify the preferred embodiment of this utility model below in conjunction with accompanying drawing.

Embodiment one

This utility model has disclosed miniature skeleton two-dimensional stress sensor, and Fig. 1-1, Fig. 1-2 are the structural representation of the miniature skeleton two-dimensional stress sensor of this utility model.See also Fig. 1-1, Fig. 1-2, the miniature skeleton two-dimensional stress sensor of this utility model mainly is made up of mechanics sensing element 1, hard center 2, chassis 3, foil gauge 4, measuring circuit 5.Mechanics sensing element 1 plays the effect that external force is measured, and when axial compressive force and radial shear masterpiece time spent, mechanics sensing element 1 can produce corresponding deformation, measures the deformation that the mechanics sensing element is produced through foil gauge 4.Based on the plate theory in Elasticity and the Plate Theory, when elastomeric thickness and inside and outside radius size in the small deflection excursion, that is:

$\frac{1}{80}\≤\frac{h}{r_1-r_2}\≤\frac{1}{8}$

In the formula, h is diaphragm-operated thickness, r ₁Be elastomeric outer radius, r ₂Be elastomeric inside radius, the elastomer of this moment can use plate theory.According to plate theory, set up the mechanical model of mechanics sensing element 1 under axial push-pull power and the effect of radial shear power, can solve the analytic solutions of the radial strain of axial push-pull power and radial shear power according to mechanical model.Like formula 1, shown in 2:

${\mathrm{\ϵ}}_{r1}=-\frac{3F_1(1-{\mathrm{\μ}}^2)}{2\mathrm{\π}{\mathrm{Eh}}^2}[\ln \frac{r}{a}+1+\frac{b^2\ln \frac{b}{a}}{a^2-b^2}(1+\frac{a^2}{r^2})]---\left(1\right)$

${\mathrm{\ϵ}}_{r2}=\frac{-3F_2\·l\·\cos \left(\mathrm{\θ}\right)}{\mathrm{\π}\·E\·h^2}({\mathrm{\μ}}^2-1)(a^2{b}^2{r}^{-3}+r-(a^2+b^2)r^{-1})---\left(2\right)$

Can be known that by formula 1,2 when the axial push-pull masterpiece time spent, the axial symmetry that should become on the diametric(al) changes, i.e. the locational strain of same radius equates; When the radial shear masterpiece time spent, owing to receive the influence of angle θ, the rotary-inversion axis symmetry that should become on the diametric(al) changes, and promptly the strain of hard both sides, center is opposite numbers.Under the situation that outer radius, thickness and material in the elastomeric physical dimension are confirmed, the linear variation of strain that force sensing element produced and active force, therefore, E type diaphragm slice structure can be used for measurement axis to pressure and radial shear power.Can be known that by principle of stacking in the small deflection scope, the action effect of making a concerted effort equals the linear superposition of two component action effects, strain and active force also are linear, and therefore, diaphragm can be used to measure the size of both direction power.Can be used for skeleton two dimension force measurement to this clear in theory diaphragm type structure that is adopted.

After having analyzed E type circular iris theoretically and can realizing axial pressure and radial shear power measured; To carry out the selection of patch location and mode to the foil gauge 4 of pick off; Reasonably patch location and mode can be so that the sensitivity of pick off improves, and can realize the static decoupling to pick off.According to the strain variation situation of mechanics sensing element under axial push-pull power and the effect of radial shear power, we have carried out the paster of pick off, according to the rotary-inversion axis symmetry variation characteristic of the axial symmetry of axial push-pull power and radial shear power; Paste 4 foil gauges 4 on the diametric(al) and be used for measurement axis to pressure; Paste 4 foil gauges 4 on the circumferencial direction and be used to measure radial shear power, concrete paster mode is as shown in Figure 2, and 8 foil gauges stick on the upper surface of mechanics sensing element 1; In order to reach maximum sensitivity; Patch location will be selected the locations of maximum strain place, also will avoid the place at zero point simultaneously, so R ₅, R ₆, R ₇, R ₈Be evenly distributed on the circumference R ₁, R ₂, R ₃, R ₄Be attached on 45 ° of directions, wherein R ₁, R ₂, R ₃, R ₄Be used for realizing the measurement to axial pressure, R ₅, R ₆, R ₇, R ₈Be used for realizing that to the radially measurement of shearing force 4 foil gauges are formed equiarm full bridge measurement circuit, the decoupling zero to axial pressure and radial shear power has been accomplished in the coupling between this group of bridge can reduce to tie up theoretically.

Fig. 2-1 is to the group bridge mode shown in Fig. 2-3 in utilization; Hole through mechanics sensing element upper surface is connected to the foil gauge lead-in wire of upper surface on the measuring circuit 5 of lower surface inner chamber; The effect that measuring circuit 5 plays the A/D conversion and amplifies; Convert the strain value of pick off into magnitude of voltage, accomplish skeleton two dimension force measurement with this.

After confirming the basic structure of skeleton 2 D force sensor, need carry out dimensionally-optimisedly to pick off, make pick off when satisfying measurement requirement, reach best static and dynamic performance.Theoretical model according to the skeleton 2 D force sensor; The linearity and sensitivity with the skeleton 2 D force sensor are the optimization aim function; Finally obtain the optimal value of inside and outside radius ratio of skeleton 2 D force sensor structural dimensions and thickness; Inside and outside radius ratio is that the sensitivity of 0.2 o'clock skeleton 2 D force sensor is best, thickness during greater than 0.8176mm the skeleton 2 D force sensor linearity best.According to the measurement requirement of skeleton 2 D force sensor, confirm the physical dimension of skeleton 2 D force sensor, shown in Fig. 3-1, Fig. 3-2.

Fig. 4 for skeleton 2 D force sensor that this utility model designed to skeleton force measurement scheme; Sensor string is connected on the boosting-rod of bone external fixator 6, and the size that skeleton 2 D force sensor 7 is measured power that boosting-rod applies realizes axial push-pull power and radial shear force measurement to skeleton.Because the volume ratio of bone external fixator is less, so that the overall dimensions of pick off 7 must can cooperate the bone external fixator to use very for a short time, in order to make the therapeutic effect of bone external fixator relatively good, requires the weight of pick off low weight.This utility model institute sensor designed weight is 47g, and maximum outside diameter is 17mm, has satisfied microminiaturized requirement.

In sum; In the miniature skeleton 2 D force sensor that this utility model proposes; Force sensing element adopts E type diaphragm slice structure; Have the advantage that size is little, highly sensitive, the linearity is good, especially the force sensing element of this simple structure taked of this utility model can be used as an one piece machine-shaping, make the good rigidity of this utility model, cost is low, dynamic property good.The skeleton 2 D force sensor that this utility model designed can cooperate the bone external fixator to realize trauma fracture section axial push-pull power and radial shear force measurement.

Embodiment two

A kind of skeleton two dimension Force sensor, said Force sensor comprises: miniature skeleton 2 D force sensor, bone external fixator, boosting-rod; Miniature skeleton 2 D force sensor such as embodiment one are said.

The skeleton 2 D force sensor is connected in the bone external fixator, and hard center is connected through screw thread with boosting-rod, acts on force measurement on the skeleton trauma section and accomplishes the two-dimentional mechanical axis of skeleton to pressure and radial shear force measurement through boosting-rod is applied to.

Here description of this utility model and application is illustrative, is not to want the scope of this utility model is limited in the above-described embodiments.Here the distortion of the embodiment that is disclosed and change are possible, and the replacement of embodiment is known with the various parts of equivalence for those those of ordinary skill in the art.Those skilled in the art are noted that under the situation of spirit that does not break away from this utility model or substitutive characteristics, and this utility model can be with other form, structure, layout, ratio, and realize with other assembly, material and parts.Under the situation that does not break away from this utility model scope and spirit, can carry out other distortion and change here to the embodiment that is disclosed.

Claims (9)

1. a miniature skeleton 2 D force sensor is characterized in that said 2 D force sensor comprises: mechanics sensing element, hard center, foil gauge, measuring circuit;

Said mechanics sensing element is promptly realized axial pressure and radial shear force measurement in order to accomplish skeleton two dimension force measurement;

The said center that is centered close to the mechanics sensing element firmly is used for bearing and transmitting external force;

Said foil gauge is attached to the upper surface of mechanics sensing element;

Said measuring circuit is accomplished conversion and the amplification to signal, and measuring circuit is fixed on the interior intracavity of mechanics sensing element lower surface.

2. miniature skeleton 2 D force sensor according to claim 1 is characterized in that:

Said mechanics sensing element adopts E type diaphragm slice structure.

3. miniature skeleton 2 D force sensor according to claim 1 is characterized in that:

Said 2 D force sensor comprises the chassis, plays the fixation of sensor effect.

4. miniature skeleton 2 D force sensor according to claim 1 is characterized in that:

Said 2 D force sensor comprises two groups of foil gauges, and on the circumference that a group is distributed in the mechanics sensing element, another group is attached on 45 ° of directions of mechanics sensing element.

5. miniature skeleton 2 D force sensor according to claim 4 is characterized in that:

Said 2 D force sensor comprises 8 foil gauge R ₁, R ₂, R ₃, R ₄, R ₅, R ₆, R ₇, R ₈

Become characteristic according to the mechanics sensing element in the axial symmetry characteristic and the symmetry of the rotary-inversion axis under the effect of radial shear power of the effect of axial push-pull power, with foil gauge R ₅, R ₆, R ₇, R ₈Be evenly distributed on the circumference of mechanics sensing element R ₁, R ₂, R ₃, R ₄Be attached on 45 ° of directions of mechanics sensing element;

Wherein, R ₁, R ₂, R ₃, R ₄Be used for realizing the measurement to axial pressure, R ₅, R ₆, R ₇, R ₈Be used for realizing to the radially measurement of shearing force; 4 foil gauges are formed equiarm full bridge measurement circuit, realize the static decoupling to two-dimentional power.

6. a skeleton two dimension Force sensor is characterized in that said Force sensor comprises: miniature skeleton 2 D force sensor, bone external fixator, boosting-rod;

Said mechanics sensing element is promptly realized axial pressure and radial shear force measurement in order to accomplish skeleton two dimension force measurement;

The said center that is centered close to the mechanics sensing element firmly is used for bearing and transmitting external force;

Said foil gauge is attached to the upper surface of mechanics sensing element;

Said measuring circuit is accomplished conversion and the amplification to signal, and measuring circuit is fixed on the interior intracavity of mechanics sensing element lower surface;

The skeleton 2 D force sensor is connected in the bone external fixator, and hard center is connected through screw thread with boosting-rod, acts on force measurement on the skeleton trauma section and accomplishes the two-dimentional mechanical axis of skeleton to pressure and radial shear force measurement through boosting-rod is applied to.

7. skeleton two dimension Force sensor according to claim 6 is characterized in that:

Said mechanics sensing element adopts E type diaphragm slice structure;

Said 2 D force sensor comprises the chassis, plays the fixation of sensor effect.

8. skeleton two dimension Force sensor according to claim 6 is characterized in that:

Said 2 D force sensor comprises two groups of foil gauges, and on the circumference that a group is distributed in the mechanics sensing element, another group is attached on 45 ° of directions of mechanics sensing element.

9. skeleton two dimension Force sensor according to claim 8 is characterized in that:

Said 2 D force sensor comprises 8 foil gauge R ₁, R ₂, R ₃, R ₄, R ₅, R ₆, R ₇, R ₈

Become characteristic according to the mechanics sensing element in the axial symmetry characteristic and the symmetry of the rotary-inversion axis under the effect of radial shear power of the effect of axial push-pull power, with foil gauge R ₅, R ₆, R ₇, R ₈Be evenly distributed on the circumference of mechanics sensing element R ₁, R ₂, R ₃, R ₄Be attached on 45 ° of directions of mechanics sensing element;

Wherein, R ₁, R ₂, R ₃, R ₄Be used for realizing the measurement to axial pressure, R ₅, R ₆, R ₇, R ₈Be used for realizing to the radially measurement of shearing force; 4 foil gauges are formed equiarm full bridge measurement circuit, realize the static decoupling to two-dimentional power.

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