Micro-air-bag type flexible three-dimensional force sensor
Technical Field
The invention relates to the technical field of physical measuring instruments, in particular to a micro-airbag type flexible three-dimensional force sensor.
Background
The mechanical sensor is a sensing device for converting various mechanical measurement quantities into electric signals, and is widely applied to various aspects in production and life. With the rapid development of electromechanical devices such as portable electronic devices, wearable devices, and intelligent robots, micro sensors having the advantages of small size, light weight, low power consumption, and high reliability are being widely used. According to the property of the manufacturing material, the mechanical sensor can be divided into an all-solid state, a semi-solid state and a flexible structure, wherein the flexible structure can be applied to the environments such as a touch sensor, robot skin and the like which need proper elasticity or match with complex shapes, so that the mechanical sensor has wider applicability.
Most of the currently used force sensors are all-solid-state or semi-solid-state structures, and the design based on a flexible structure is less. Moreover, most force sensors directly convert mechanical information into electrical signals based on a capacitance principle or a piezoresistive principle, which requires a complex signal processing circuit integrated inside a flexible structure, and is not favorable for manufacturing of an array sensor.
Disclosure of Invention
The invention aims to provide a micro-air bag type flexible three-dimensional force sensor which can realize the measurement of three-dimensional force, reduce the processing difficulty of the flexible three-dimensional force sensor and improve the usability.
In order to achieve the purpose, the invention adopts the following technical scheme:
a micro-air bag type flexible three-dimensional force sensor comprises a flexible force transmission column and a flexible base arranged below the flexible force transmission column; the bottom of the flexible force transmission column is provided with a plurality of upper micro air bags which are uniformly distributed; the flexible base is provided with a lower micro air bag; and the upper micro air bag and the lower micro air bag are respectively provided with a micro pressure sensor. The central axis of the flexible elastic column is used as a central line, and the plurality of upper micro air bags are uniformly and symmetrically distributed along the outer circumference of the bottom of the flexible force transmission column.
Furthermore, the bottom surface of the flexible force transmission column is connected with the top surface of the flexible base in an adhesive mode, and the central axis of the flexible force transmission column, the central axis of the flexible base and the central axis of the lower micro air bag coincide with each other.
Furthermore, the upper micro air bag is a groove formed in the bottom of the flexible force transmission column, and an opening at the lower end of the groove is sealed by the top surface of the flexible base. The plurality of upper micro air bags are uniformly distributed on the periphery of the lower micro air bag, and the upper micro air bags are not contacted with or communicated with the lower micro air bags.
Furthermore, the lower micro air bag is a through hole arranged in the middle of the flexible base, the opening at the top of the through hole is sealed by the bottom surface of the flexible force transmission column, and the opening at the bottom of the through hole is sealed by silicon rubber.
Furthermore, the lower micro air bag is a semi-buried hole with an upward opening formed in the middle of the flexible base, and the opening at the top of the semi-buried hole is sealed by the bottom surface of the flexible force transmission column.
Furthermore, the upper micro air bag and the lower micro air bag are distributed in a staggered mode. The upper micro air bag senses tangential force, and the lower micro air bag senses normal pressure.
Furthermore, the flexible force transmission column is a cylinder made of flexible silicon rubber.
Furthermore, the flexible base is an elastic gasket which is made of flexible silicon rubber and has a regular shape.
According to the technical scheme, the upper micro air bags and the lower micro air bags are embedded in the flexible force transmission column and the flexible base in a certain arrangement mode, and the air pressure change in each micro air bag is measured through the micro pressure sensors arranged in each micro air bag, so that the applied loading force is measured, and the three-dimensional force measurement is realized. The invention reduces the processing difficulty of the flexible three-dimensional force sensor and improves the usability.
Drawings
FIG. 1 is a schematic structural view of the present invention;
fig. 2 is a schematic cross-sectional structure of the present invention.
Wherein:
1. the flexible force transmission column comprises 21-24 parts of an upper micro air bag 3 parts of a flexible base 4 parts of a lower micro air bag.
Detailed Description
The invention is further described below with reference to the accompanying drawings:
the micro-air bag type flexible three-dimensional force sensor as shown in fig. 1-2 comprises a flexible force transmission column 1 and a flexible base 3 arranged below the flexible force transmission column 1. The bottom of the flexible force transmission column 1 is provided with 4 upper micro air bags 21-24 which are uniformly distributed. The central axis of the flexible elastic column is used as a central line, and 4 upper micro air bags are uniformly and symmetrically distributed along the outer circumference of the bottom of the flexible force transmission column. The flexible base 3 is provided with a lower micro air bag 4. Miniature pressure sensors are arranged in the upper miniature air bags 21-24 and the lower miniature air bag 4; the micro pressure sensor is used for detecting the air pressure change in the upper micro air bag or the lower micro air bag. The lower surface of the flexible base 3 is bonded with a signal acquisition circuit or other supporting structures to realize the fixation of the whole sensor.
Furthermore, flexible dowel pin 1 is the elastic cylinder who adopts flexible silicon rubber material to make, and the cylinder appearance ensures that flexible dowel pin 1 can not receive the extra resistance that irregular appearance arouses when arbitrary direction bending deformation in the xy plane. The flexible force transmission column 1 can change the size and the height according to actual requirements, so that different sensor measuring ranges and sensitivities are realized.
Furthermore, the bottom surface of the flexible force transmission column 1 is bonded with the top surface of the flexible base 3, and the central axis of the flexible force transmission column 1, the central axis of the flexible base 3 and the central axis of the lower micro air bag 4 are overlapped.
Further, the upper micro air bags 21 to 24 are grooves with downward openings formed at the bottom of the flexible force transmission column 1, and the openings at the lower ends of the grooves are sealed by the top surface of the flexible base 3. The 4 upper micro air bags 21-24 are evenly distributed on the periphery of the lower micro air bag 4, and the upper micro air bags 21-24 are not contacted with or communicated with the lower micro air bag 4. Two groups of upper micro air bags 21, 24 and 22, 23 which are symmetrical in pairs respectively sense acting forces in the x and y directions or the y and x directions. The upper micro air bags 21-24 can change the size and the shape according to actual requirements, and adjust the air pressure in the upper micro air bags, so that different sensor measuring ranges and sensitivities are realized.
Further, the lower micro air bag 4 is a through hole formed in the center of the flexible base 3, the opening at the top of the through hole is sealed by the bottom surface of the flexible force transmission column 1, and the opening at the bottom of the through hole is sealed by silicon rubber. Or, the lower micro-airbag 4 is a half buried hole with an upward opening formed in the center of the flexible base 3, and the opening at the top of the half buried hole is sealed by the bottom surface of the flexible force transmission column 1. And the lower micro air bag 4 is used for sensing acting force in the z direction. The size and the shape of the lower micro air bag 4 can be changed according to actual requirements, and the air pressure in the lower micro air bag is adjusted, so that different sensor measuring ranges and sensitivity are realized.
Further, the upper micro-balloons 21 to 24 and the lower micro-balloons 4 are distributed in a staggered manner. The upper micro-balloons 21-24 are arranged above the top of the flexible base 3 and are easy to induce tangential force, and the lower micro-balloon 4 is arranged in the flexible base 3 and induces normal pressure which is insensitive to the tangential force. When the upper micro-balloons 21 to 24 are deformed by a tangential force, the deformation of the lower micro-balloon 4 is not caused or greatly reduced.
Further, the flexible base 3 is an elastic gasket which is made of flexible silicon rubber and has a regular shape. Preferably, the regular shape is rectangular or circular.
The working principle of the invention is as follows:
in use, when the sensor is stressed, the applied force is decomposed into three directions of x, y and z by the flexible force transmission column 1. The upper micro air bag and the lower micro air bag in the three directions deform after being stressed, and the air pressure change of each micro air bag is measured through each micro pressure sensor, so that the stress condition in each direction is sensed. The calculation method of the stress in each direction is as follows:
Fx=α(P24-P21)
Fy=β(P22-P23)
Fz=γP4
the force sensors are respectively connected with the micro pressure sensors, wherein the Fx, the Fy and the Fz are respectively applied to the force sensors in the x, y and z directions; p21、P22、P23、P24And P4The pressures of the upper micro-balloons 21, 22, 23, 24 and the lower micro-balloon 4, respectively, and α, β and gamma are conversion coefficients.
The above-mentioned embodiments are merely illustrative of the preferred embodiments of the present invention, and do not limit the scope of the present invention, and various modifications and improvements of the technical solution of the present invention by those skilled in the art should fall within the protection scope defined by the claims of the present invention without departing from the spirit of the present invention.