CN112414607A

CN112414607A - Capacitive six-dimensional force sensor with composite beam structure

Info

Publication number: CN112414607A
Application number: CN202011357920.0A
Authority: CN
Inventors: 蒲明辉; 罗祺; 胡世通; 骆照阳; 尹飞
Original assignee: Guangxi University
Current assignee: Guangxi University
Priority date: 2020-11-27
Filing date: 2020-11-27
Publication date: 2021-02-26

Abstract

The invention discloses a capacitive six-dimensional force sensor with a composite beam structure, which comprises a sensor main body, an insulating gasket, an induction movable electrode layer and a PCB (printed Circuit Board). The sensor main body mainly comprises a stress platform, an outer wall and a deformation beam connected between the outer wall and the stress platform, wherein the deformation beam is of a composite beam structure and comprises a cross beam, a vertical beam and a longitudinal beam. The insulating gasket and the induction moving electrode layer are fixedly connected to the sensor main body stress platform through insulating screws, and the PCB is fixed to a PCB mounting platform on the inner side of the outer wall of the sensor and forms six capacitors with the induction moving electrode layer. The invention adopts the composite beam as the deformation beam, reduces the bending rigidity of the whole deformation beam by adding the vertical beam and the longitudinal beam on the basis of the common equal-section cross beam, ensures that the bending rigidity of the capacitance type six-dimensional force sensor in all directions is similar, the response of the deformation beam in the transmission process of the force in any direction is more sensitive, and the sensitivity of the sensor in all directions is similar.

Description

Capacitive six-dimensional force sensor with composite beam structure

Technical Field

The invention belongs to the technical field of sensors, relates to a force sensor, and particularly relates to a capacitive six-dimensional force sensor with a composite beam structure.

Background

The six-dimensional force sensor is used as a medium for mechanical information exchange between the robot and the environment, can realize measurement of multi-dimensional force signals, and has wide application in the fields of machining, automobile manufacturing, intelligent robots, aerospace and the like. At present, a six-dimensional force sensor based on a resistance strain principle is mature, but the six-dimensional force sensor is complex in circuit design, high in processing technology requirement and high in price. The capacitive six-dimensional force sensor has the advantages of simple structure, good dynamic performance, non-contact measurement and longer service life compared with a resistance strain gauge. However, most of the elastic bodies used by the capacitive six-dimensional force sensors are of a straight beam structure with an equal section, and the bending rigidity in certain directions is too high when the elastic bodies are stressed, so that the sensitivity of the sensors in all directions is inconsistent.

Disclosure of Invention

The invention aims to provide a capacitive six-dimensional force sensor with a composite beam structure aiming at the defects of the conventional capacitive six-dimensional force sensor, the overall bending rigidity of a deformation beam is reduced through the design of the composite beam structure, the sensitivity of the capacitive six-dimensional force sensor is improved, and the sensitivities of the capacitive six-dimensional force sensor in all directions are similar.

In order to achieve the above object, the technical solution of the present invention is as follows:

a capacitive six-dimensional force sensor with a composite beam structure comprises a sensor main body 1, an insulating gasket 2, an induction movable electrode layer 3 and a PCB (printed Circuit Board) 4; the sensor body 1 at least comprises an outer wall 5, a deformation beam 6 and a stress platform 7; a groove 8, a PCB mounting table 9 and a wiring hole 10 are formed in the inner side of the outer wall 5;

the deformation beam 6 is of a composite beam structure and at least comprises a cross beam 6-1, a vertical beam 6-2 and a longitudinal beam 6-3; one end of the cross beam 6-1 is fixedly connected to the outer side of the stress platform 7, and the other end of the cross beam is vertically connected to the lower end of the vertical beam 6-2; the upper end of the vertical beam 6-2 is vertically connected to the middle position of the longitudinal beam 6-3; both ends of the longitudinal beam 6-3 are connected to both sides of the groove 8 on the inner side of the outer wall 5; the deformation beams 6 are 3 in number and are uniformly distributed around the Z axis at an angle of 120 degrees. The deformation beam 6 is a composite beam, namely a vertical beam 6-2 and a longitudinal beam 6-3 are added on the basis of a common equal-section cross beam 6-1, and when the sensor is subjected to any force in any space, the bending rigidity in each direction is similar, so that the sensitivity of the sensor in each direction is similar.

The insulating gasket 2 is positioned between the stress platform 7 and the induction movable electrode layer 3, and the insulating gasket 2 and the induction movable electrode layer 3 are connected to the stress platform 7 through insulating screws; the insulating gasket 2 is used for separating the sensor main body 1 from the induction movable electrode layer 3 to electrically isolate the sensor main body and the induction movable electrode layer, so that electromagnetic interference on a capacitor caused by a charged body approaching or contacting the outer wall 5 of the sensor in the use process of the sensor is reduced, and the measurement accuracy of the sensor is improved; the PCB 4 is mounted on the PCB mounting table 9 through screws.

The induction movable electrode layer 2 is provided with parallel plate capacitive movable electrodes 11 and vertical capacitive movable electrodes 12, the number of the parallel plate capacitive movable electrodes and the vertical capacitive movable electrodes is 3, and the parallel plate capacitive movable electrodes and the vertical capacitive movable electrodes are distributed in a crossed mode around a Z axis at an included angle of 60 degrees. The PCB 4 is provided with a parallel plate capacitance static electrode 13 and a vertical capacitance static electrode 14; the parallel plate capacitance moving electrode 11 and the parallel plate capacitance static electrode 13 form a parallel plate capacitor 15; the vertical capacitive electrode 12 and the vertical capacitive electrode 14 form a vertical capacitor 16, and the vertical capacitor 16 has a differential structure to improve the sensitivity and linearity of the sensor.

The invention has the characteristics and beneficial effects that:

(1) the invention adopts the composite beam structure deformation beam, improves the whole bending rigidity of the sensor deformation beam by adding the vertical beam and the longitudinal beam on the basis of the common straight beam with equal section, improves the sensitivity of the capacitive six-dimensional force sensor, and leads the sensitivity of the capacitive six-dimensional force sensor to be similar in all directions.

Drawings

FIG. 1 is an overall exploded view of the present invention;

FIG. 2 is a schematic diagram of the main structure of the sensor of the present invention;

FIG. 3 is a schematic view of the assembly of the sensor body and the inductive electrode layer of the present invention;

FIG. 4 is a schematic diagram of a capacitor structure according to the present invention;

in the drawings: 1. a sensor body; 2. an insulating spacer; 3. an inductive dynamic electrode layer; 4, PCB board; 5. an outer wall; 6. a deformation beam; 6-1, a cross beam; 6-2. vertical beam; 6-3, longitudinal beam; 7. a stress platform; 8. a groove; 9, a PCB mounting table; 10. a wiring hole; 11. a parallel-plate capacitive moving electrode; 12. a vertical capacitive moving electrode; 13. a parallel plate capacitive static electrode; 14. a vertical capacitive static electrode; 15. a parallel plate capacitor; 16. a vertical type capacitor.

Detailed Description

For a better understanding of the present invention, exemplary embodiments thereof will be described below with reference to the accompanying drawings.

As shown in fig. 1, a capacitive six-dimensional force sensor with a composite beam structure includes a sensor body 1, an insulating spacer 2, an inductive dynamic electrode layer 3, and a PCB 4; the sensor body 1 at least comprises an outer wall 5, a deformation beam 6 and a stress platform 7; a groove 8, a PCB mounting table 9 and a wiring hole 10 are formed in the inner side of the outer wall 5;

as shown in fig. 2, the deformation beam 6 is a composite beam structure and at least comprises a cross beam 6-1, a vertical beam 6-2 and a longitudinal beam 6-3; one end of the cross beam 6-1 is fixedly connected to the outer side of the stress platform 7, and the other end of the cross beam is vertically connected to the lower end of the vertical beam 6-2; the upper end of the vertical beam 6-2 is vertically connected to the middle position of the longitudinal beam 6-3; both ends of the longitudinal beam 6-3 are connected to both sides of the groove 8 on the inner side of the outer wall 5; the deformation beams 6 are 3 in number and are uniformly distributed around the Z axis at an angle of 120 degrees. The deformation beam 6 is a composite beam, namely a vertical beam 6-2 and a longitudinal beam 6-3 are added on the basis of a common uniform-section cross beam 6-1, and when the deformation beam 6 is subjected to any space force, the bending rigidity in all directions is reduced.

As shown in fig. 3, the insulating gasket 2 is located between the force bearing platform 7 and the induction movable electrode layer 3, and the insulating gasket 2 and the induction movable electrode layer 3 are connected to the force bearing platform 7 through insulating screws; the insulating gasket 2 is used for separating the sensor main body 1 from the induction movable electrode layer 3 to electrically isolate the sensor main body and the induction movable electrode layer, so that electromagnetic interference on a capacitor caused by a charged body approaching or contacting the outer wall 5 of the sensor in the use process of the sensor is reduced, and the measurement accuracy of the sensor is improved; the PCB 4 is mounted on the PCB mounting table 9 through screws.

As shown in fig. 4, the inductive active electrode layer 2 has 3 parallel plate capacitive

active electrodes

11 and 3 vertical capacitive active electrodes 12, which are distributed in a crossed manner around the Z-axis at an angle of 60 °. The PCB 4 is provided with parallel plate capacitance static electrodes 13 and vertical capacitance static electrodes 14, the number of the static electrodes is 3, and the static electrodes and the vertical capacitance static electrodes are distributed in a crossed way around a Z axis at an included angle of 60 degrees; the parallel plate capacitance moving electrode 11 and the parallel plate capacitance static electrode 13 form a parallel plate capacitor 15; the vertical capacitive electrode 12 and the vertical capacitive electrode 14 form a vertical capacitor 16, and the vertical capacitor 16 has a differential structure to improve the sensitivity and linearity of the sensor.

The working principle is that when the sensor works, the outer wall 5 is fixed, and when the sensor stress platform 7 is subjected to any force, the force can be decomposed into F_X、F_Y、F_Z、M_X、M_Y、M_ZSix-dimensional space force, which deforms the deformation beam 6, thereby changing the polar distance of the six capacitors, the corresponding capacitance change value is Δ C₁、ΔC₂、ΔC₃、ΔC₄、ΔC₅、ΔC₆. Assuming that the input force and the capacitance change are in a linear relationship, a 6 × 6 matrix a can be obtained through experiments, and the following decoupling formula is established:

F＝AΔC

wherein F ═ F_X,F_Y,F_Z,M_X,M_Y,M_Z)^T,ΔC＝(ΔC₁,ΔC₂,ΔC₃,ΔC₄,ΔC₅,ΔC₆)^T；

F_X、F_Y、F_ZRespectively showing the force in the X direction, the force in the Y direction and the force in the Z direction, and the unit is N;

M_X、M_Y、M_Zrespectively showing the moment in the X direction, the moment in the Y direction and the moment in the Z direction, wherein the unit is N.m;

from the above analysis, the six-dimensional space force F can be obtained_X、F_Y、F_Z、M_X、M_Y、M_ZThe value of (c).

Finally, the above description is only a preferred embodiment of the present invention, and the present invention is not limited to the above embodiment, and various modifications and variations can be made. The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.

Claims

1. A capacitive six-dimensional force sensor with a composite beam structure is characterized in that: the sensor at least comprises a sensor main body (1), an insulating gasket (2), an induction movable electrode layer (3) and a PCB (printed circuit board) (4); the sensor main body (1) at least comprises an outer wall (5), a deformation beam (6) and a stress platform (7); the outer wall (5) is provided with a groove (8), a PCB mounting table (9) and a wiring hole (10);

the deformation beam (6) is of a composite beam structure and at least comprises a cross beam (6-1), a vertical beam (6-2) and a longitudinal beam (6-3); one end of the cross beam (6-1) is fixedly connected to the outer side of the stress platform (7), and the other end of the cross beam is vertically connected to the lower end of the vertical beam (6-2); the upper end of the vertical beam (6-2) is vertically connected to the middle position of the longitudinal beam (6-3); both ends of the longitudinal beam (6-3) are connected to both sides of the groove (8) on the inner side of the outer wall (5);

the insulating gasket (2) is positioned between the stress platform (7) and the induction movable electrode layer (3), and the insulating gasket (2) and the induction movable electrode layer (3) are connected to the stress platform (7) through insulating screws; the PCB (4) is arranged on the PCB mounting table (9).

2. The capacitive six-dimensional force sensor with a composite beam structure of claim 1, wherein: the induction movable electrode layer (3) is provided with a parallel plate capacitance movable electrode (11) and a vertical capacitance movable electrode (12), and the two electrodes are uniformly distributed around a Z axis at an included angle of 60 degrees.

3. The capacitive six-dimensional force sensor with a composite beam structure of claim 2, wherein: the PCB (4) at least comprises a parallel plate capacitance static electrode (13) and a vertical capacitance static electrode (14).

4. A capacitive six-dimensional force sensor with a composite beam structure according to claim 3, wherein: the parallel plate capacitance moving electrode (11) and the parallel plate capacitance static electrode (13) form a parallel plate capacitor (15); the vertical capacitive movable electrode (12) and the vertical capacitive static electrode (14) form a vertical capacitor (16).