CN115219091A - Small-sized multidimensional force sensor for active control system - Google Patents

Abstract

The present invention relates to the field of sensor technology, in particular to a small multi-dimensional force sensor for an active control system, comprising: a casing, an upper base fixed on the top of the casing, a mounting base arranged on the bottom of the casing, a The elastic body, the strain gauge, the support ring and the PCB board inside the shell; the elastic body includes an upper support piece, a lower support piece and a middle connecting part, and the two ends of the middle connecting part are respectively connected to the upper support piece and the middle connecting part. The lower support, the middle connecting part includes an upper body, a lower body and a side body, one end of the upper body is connected to the side bottom of the upper support, and one end of the lower body is connected to the side of the lower support At the top, the other end of the upper body and the other end of the lower body are respectively connected to the upper end and the lower end of the side body, and the strain gauge is installed at the upper body and the lower body of the middle connecting part. The present invention can achieve high precision and high reliability.

Description

A Small Multidimensional Force Sensor for Active Control Systems

technical field

The invention relates to the technical field of sensors, in particular to a small multi-dimensional force sensor used in an active control system.

Background technique

A multi-dimensional force sensor is a sensing element that can simultaneously detect force or torque information in no less than two directions in three-dimensional space. As one of the key components of intelligent equipment and tools, multi-dimensional force sensors have broad application prospects in the fields of human motion data, biomedicine, intelligent equipment, and aerospace. The needs of multi-dimensional force sensors in the legs, shoulders, feet, wrists and even fingertips of robots are becoming more and more extensive and diversified, and they are usually integrated with other sensors to collect real-time environmental information of various actuators . For these applications, on the basis of satisfying basic performance requirements such as accuracy, sensitivity, and measurement range, multi-dimensional force sensors need to meet the needs of integrated applications in form, that is, small size, and high reliability. The existing multi-dimensional force sensors are often bulky, and it is difficult to achieve the requirements of small size and hardware redundancy at the same time.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is that it is difficult for the existing multi-dimensional force sensor to achieve high precision and high reliability while ensuring a small volume.

The technical solution adopted by the present invention to solve the technical problem is to provide a small multi-dimensional force sensor for an active control system, comprising: a casing, an upper base fixed on the top of the casing, a A mounting base, an elastic body, a strain gauge, a support ring and a PCB board installed inside the casing; the elastic body includes an upper support piece, a lower support piece and a middle connecting part, and two ends of the middle connecting part are respectively connected to the The upper support and the lower support, the middle connecting part includes an upper body, a lower body and a side body, one end of the upper body is connected to the side bottom of the upper support, and one end of the lower body is connected to the lower support The top of the side surface, the other end of the upper body and the other end of the lower body are respectively connected to the upper end and the lower end of the side body, the side body is far away from the upper support and the lower support, and the strain gauge is installed on the The upper body and the lower body of the connecting part are mentioned above.

Further, the number of the middle connecting portion is four, the middle connecting portion is U-shaped as a whole, and the opening of the middle connecting portion faces the central axis of the upper support member.

Further, the middle connecting parts are evenly distributed circumferentially along the central axis of the upper support.

Further, the installation positions of the strain gauges on each of the middle connecting portions correspond to each other.

Further, in the upper body of the two opposite middle connecting parts, two strain gauges close to the upper support member form a first measurement bridge; The strain gauge of the side body is combined with a preset fixed resistance to form a second measurement bridge.

Further, two support rings are provided, and the support rings are respectively sleeved at the upper and lower ends of the middle connecting portion.

Further, the number of the PCB boards is set to two, and the PCB boards are respectively fixed on the support rings.

The beneficial effect of the present invention is that the tangential strain on the elastic body in the small multi-dimensional force sensor for active control system of the present invention is orthogonal to the current measured strain direction, so the structure of the elastic body has low tangential strain. Since the two adjacent middle connecting parts in the elastic body are perpendicular to each other, when only the X-direction load or the Y-direction load is applied, the measured strain in the other direction is small, and low crosstalk is achieved; the two opposite middle connecting parts are The upper body and the lower body form a strain field in one direction, and the four middle connecting parts form two strain fields. The directivity of the two strain fields follows a perfect cosine relationship. When the load is applied from the X direction and the Y direction at the same time, Each component is easy to calculate; the elastic part contains four middle connecting parts and the four middle connecting parts are separated from each other, which can produce the minimum crosstalk effect; since the upper and lower support parts of the elastic body are hollow, which makes it difficult for installation. The directional load applied on the rod has the greatest sensitivity; the upper and lower end faces of the upper body or lower body in the elastic body produce equivalent strain, and strain gauges are installed on the upper and lower end faces of the upper body or lower body, resulting in More inspection channels for optimum redundancy and safety; the elastomer is located in the middle of the mounting rod, isolating parasitic loads from above the upper support and below the lower support during installation.

Description of drawings

The present invention will be further described below with reference to the accompanying drawings and embodiments.

1 is a schematic structural diagram of a small multi-dimensional force sensor for an active control system of the present invention;

Fig. 2 is the exploded schematic diagram of the small multi-dimensional force sensor for active control system of the present invention;

Fig. 3 is the exploded schematic diagram of elastomer of the present invention, support ring and PCB board;

Fig. 4 is the structural representation of the lower base of the present invention;

Fig. 5 is the structural representation of the elastomer of the present invention;

Fig. 6 is the schematic diagram of the upper end face of the strain gauge and elastic body of the present invention;

Fig. 7 is the schematic diagram of the lower end face of the strain gauge and the elastic body of the present invention;

8 is a schematic diagram of the connection of the bridge circuit of the strain gauge of the small multi-dimensional force sensor used in the active control system of the present invention.

The names and numbers of the parts in the figure are: shell 1, upper base 2, lower base 3, base 31, mounting rod 32; elastic body 4, upper support 41, lower support 42, middle connecting part 43, Upper body 431 , lower body 432 , side body 433 ; strain gauge 5 , support ring 6 , PCB board 7 .

Detailed ways

The present invention will now be described in detail with reference to the accompanying drawings. This figure is a simplified schematic diagram, and only illustrates the basic structure of the present invention in a schematic manner, so it only shows the structure related to the present invention.

As shown in Figures 1-3, the small multi-dimensional force sensor 100 for an active control system of the present invention includes: a casing 1, an upper base 2 fixed on the top of the casing 1, and a mounting base 3 arranged at the bottom of the casing , The elastic body 4 , the strain gauge 5 , the support ring 6 and the PCB board 7 are installed inside the casing.

Specifically, the outer casing 1 is a square shell portion, and the outer casing 1 is provided with mounting holes and bolts to facilitate assembly and fixation. The upper base 2 has a circular shape and is installed on the top of the casing 1. A circular through hole is formed in the center of the upper base 2, which is suitable for placing cables. As shown in FIG. 4 , the lower base 3 includes a base 31 and an installation rod 32 vertically fixed in the center of the base 31 . The upper end surface of the installation rod 32 is provided with a circular through hole that penetrates up and down, and the installation rod 32 is suitable for passing cables through. The diameter of the circular through hole is equal to that of the circular through hole opened in the center of the upper base 2 .

Specifically, as shown in FIG. 5 , the elastic body 4 includes an upper support member 41 , a lower support member 42 , and a middle connecting portion 43 . The upper support member 41 is a cylindrical shape that penetrates through the inside, and is provided at the upper end of the middle connecting portion 43 . The central diameter of the upper support 41 matches the diameter of the mounting rod 32 . The lower support member 42 is in the shape of a cylinder that penetrates through the inside, and is provided at the lower end of the middle connecting portion 43 . The center of the lower support 42 is fitted with the mounting rod 32 . Both ends of the middle connecting portion 43 are respectively connected to the upper support 41 and the lower support 42 . form a hollow structure. The number of the middle connecting portion 43 is four, the middle connecting portion 43 is U-shaped as a whole, the opening of the middle connecting portion 43 faces the central axis of the upper support member 41 , and the middle connecting portion 43 is along the central axis of the upper supporting member 41 . uniform circumferential distribution. The middle connecting part 43 includes the upper body 431, the lower body 432 and the side body 433, that is, the upper body 431, the side body 433 and the lower body 432 form a U-shaped middle connecting part 43 in turn, and one end of the upper body 431 is connected to the upper part of the support 41. At the bottom of the side, one end of the lower body 432 is connected to the top of the side of the lower support 42, the other end of the upper body 431 and the other end of the lower body 432 are respectively connected to the upper and lower ends of the side body 433, and the side body 433 is far away from the upper support 41 and the lower support 42 , the upper end surface of the upper body 431 is a horizontal plane, suitable for installing the strain gauge 5 , and the lower end surface of the lower body 432 is a horizontal plane, suitable for installing the strain gauge 5 . The elastic body 4 is sleeved on the outer surface of the mounting rod 32. Since the four middle connecting parts 43 are respectively evenly distributed around the central axis of the upper support member 41, when the mounting rod 32 is subjected to a force, the elastic member can The different middle connecting parts 43 on the 4 are deformed, and each middle connecting part 43 is dispersedly arranged, and the adjacent middle connecting parts 43 are perpendicular to each other, which greatly reduces the generation of crosstalk effect. And the center of the elastic body 4 is a hollow structure, when the force on the mounting rod 32 acts, the sensitivity of the strain gauges 6 on the upper body 431 and the lower body 432 is improved.

Specifically, a plurality of strain gauges 5 are provided, and the distribution of the strain gauges 5 installed on each middle connecting portion 43 corresponds to each other. Three strain gauges 5 are mounted on the upper end face, and three strain gauges 5 that are symmetrical to the strain gauges 5 on the upper face body 431 are mounted on the lower end face of the lower face body 432 .

Specifically, there are two support rings 6 , the support rings 6 are respectively sleeved at the upper and lower ends of the middle connecting portion 43 , and there are two PCB boards 7 , and the PCB boards 7 are respectively fixed on the support rings 6 . , connect the strain gauges 6 to the PCB board 7 correspondingly.

In this embodiment, as shown in FIGS. 6 and 7 , there are 24 strain gauges 5 in total, which are respectively numbered as: Gage1, Gage2, Gage3...Gage24. Three strain gauges 5 are respectively installed on the upper end surface of each upper body 431 and the lower end surface of each lower body 432 . In the upper body 431 of the two opposite middle connecting parts 43, between the two strain gauges 5 close to the upper support 41, a first measurement bridge is formed, and there are two first measurement bridges, corresponding to the measurement X Directional Strain Force and Measured Y-direction Strain Force. In the upper body 431 of the two opposite middle connecting parts 43, between the strain gauges close to the side body 433, combined with the preset fixed resistance R, a second measurement bridge is formed, and the second measurement bridge has two Each of them corresponds to measuring the strain force in the X direction and measuring the strain force in the Y direction, respectively. In the lower body 432 of the two opposite middle connecting parts 43, between the two strain gauges 5 close to the lower support 42, a third measurement bridge is formed, and there are two third measurement bridges, corresponding to the measurement X Directional Strain Force and Measured Y-direction Strain Force. In the lower body 432 of the two opposite middle connecting parts 43, between the strain gauges 5 near the side body 433, combined with the preset fixed resistance R, a fourth measurement bridge is formed, and the fourth measurement bridge has Two, corresponding to measuring the strain force in the X direction and measuring the strain force in the Y direction. The first measurement bridge, the second measurement bridge, the third measurement bridge and the fourth measurement bridge are respectively provided with two, and a total of 8 bridge circuits are formed.

Specifically, as shown in FIG. 8 , 8 types of bridge circuits composed of 24 strain gauges 5 can realize at least dual redundant outputs, and the specific connections are as follows.

The first measurement bridge includes Gage2, Gage3, Gage8 and Gage 9 to form a bridge circuit, the strain force in the Y direction; Gage5, Gage6, Gage11 and Gage12 form a bridge circuit, the strain force in the X direction.

The second measurement bridge includes Gage1, Gage7 and two fixed resistors R to form a bridge circuit, the strain force in the Y direction; Gage4, Gage10 and two fixed resistors R form a bridge circuit, the strain force in the X direction.

The third measurement bridge includes Gage14, Gage15, Gage20 and Gage21 to form a bridge circuit, and the strain in the Y direction; Gage17, Gage18, Gage23 and Gage24 form a bridge circuit, and the strain in the X direction.

The fourth measurement bridge includes Gage13, Gage19 and two fixed resistors R to form a bridge circuit, with strain in the Y direction; Gage16, Gage22 and two fixed resistors R form a bridge circuit, with strain in the X direction.

The composition of the bridge circuit given above can directly sense the XY direction forces, and can achieve a 4-fold redundant design, that is, 4 bridge circuits output the X direction force signal, and 4 bridge circuits output the Y direction force. Signal.

In some examples, after the strain gauge 5 forms an electrical bridge, the resistance changes correspondingly according to the strain of the elastic body, and a signal output is generated through the electrical bridge. By changing the layout of the bridge circuit, three strain gauges 5 and a fixed resistor R are installed on the same upper body 431 or lower body 432 to form eight bridge circuits, then the strain force measurement in at least three directions of XYZ can be achieved , at least 2x redundancy can be achieved. If it is possible to increase the number of strain gauges 5 of the upper body 431 or the lower body 432, from the original 3 to 4, the same way of using one upper body 431 or the lower body 432 of 5 strain gauges in the same bridge , which is a full-bridge circuit.

The tangential strain on the elastic body 4 in the small multi-dimensional force sensor 100 for an active control system of the present invention is orthogonal to the current measured strain direction, so the structure of the elastic body 4 has low tangential strain. Since the two adjacent middle connecting parts 43 in the elastic body 4 are perpendicular to each other, when only the X-direction load or the Y-direction load is applied, the measured strain in the other direction is small, and low crosstalk is achieved; The upper body and the lower body on the connecting part form a strain field in one direction, and the four middle connecting parts form two strain fields. The directivity of the two strain fields follows a perfect cosine relationship. When the load is applied from the X direction and the Y direction at the same time , each component is easy to calculate; the elastic member 4 includes four middle connecting parts 43 and the four middle connecting parts 43 are separated from each other, which can produce the minimum crosstalk effect; It is hollow, which gives the maximum sensitivity to the directional load applied on the mounting rod 32; the upper and lower end faces of the upper body 431 or the lower body 432 in the elastic body 4 produce equivalent strains, and the upper body 431 or the lower body 432 produces equivalent strains Strain gauges 5 are mounted on the upper and lower end faces of the 432, resulting in more detection channels for optimal redundancy and safety; the elastomer 4 is located in the middle of the mounting rod 32 to isolate the top and bottom straps during installation coming parasitic loads.

Taking the above ideal embodiments according to the present invention as inspiration, and through the above description, relevant personnel can make various changes and modifications without departing from the scope of the present invention. The technical scope of the present invention is not limited to the contents in the specification, and the technical scope must be determined according to the scope of the claims.

Claims (7)

1. A compact multi-dimensional force sensor for an active control system, comprising: the device comprises a shell, an upper base fixed on the top of the shell, a mounting base arranged at the bottom of the shell, an elastic body arranged in the shell, a strain gauge, a support ring and a PCB (printed circuit board); the elastomer includes upper support piece, bottom suspension member and well connecting portion, well connecting portion both ends are connected respectively upper support piece with the bottom suspension member, well connecting portion include the upper surface body, the lower surface body and the side face body, the one end of upper surface body is connected the side bottom of upper support piece, the one end of the lower surface body is connected the side top of bottom suspension member, the other end of the upper surface body and the other end of the lower body are connected respectively the upper end and the lower extreme of the side face body, the side face body is kept away from upper support piece and bottom suspension member, the foil gage is installed the upper surface body and the lower body department of well connecting portion.

2. The small multi-dimensional force sensor for an active control system according to claim 1, wherein the number of the middle connecting portions is four, the middle connecting portions are U-shaped as a whole, and the opening of the middle connecting portions faces the central axis of the upper support.

3. The miniaturized, multi-dimensional force sensor for an active control system of claim 2 wherein the middle connections are evenly circumferentially distributed along a central axis of the upper support.

4. A miniature multi-dimensional force sensor for an active control system as set forth in claim 3 wherein the mounting location of said strain gage on each of said interconnecting sections corresponds.

5. The miniaturized multi-dimensional force sensor for active control system of claim 4, wherein two strain gauges close to said upper support member in the upper body of two opposite middle connection portions constitute a first measuring bridge; in the upper surface bodies of the two opposite middle connecting parts, the strain gauges close to the side surface bodies are combined with preset fixed resistors to form a second measuring bridge.

6. The miniaturized multi-dimensional force transducer for active control system of claim 1, wherein there are two of said support rings, said support rings being fitted over the upper and lower ends of said middle connection portion, respectively.

7. The miniaturized multi-dimensional force sensor for active control system of claim 6, wherein the number of the PCB boards is set to two, and the PCB boards are respectively fixed on the support ring.

Images