Ring-shaped device and measurement method capable of measuring magnitude, direction and action point of multi-dimensional force

Abstract

The present invention relates to an annular device capable of measuring the magnitude, direction and action point of multi-dimensional force, characterized in that it comprises an outer ring elastic body, an inner cylindrical elastic body, connecting elastic ribs, flexible electrodes, a hemispherical elastic body and a capacitance measurement module; the present invention uses four cross-shaped connecting elastic ribs to make the floating inner cylindrical elastic body displace relative to the fixed outer ring elastic body when subjected to force, thereby realizing the physical quantity conversion from force to deformation; at the same time, the flexible electrodes are divided into four groups, each group includes two flexible electrode sheets of the same size, and each group of flexible electrode sheets is respectively attached to the inner surface of the outer ring elastic body and the outer surface of the inner cylindrical elastic body, thereby realizing the physical quantity conversion from deformation to capacitance value change; each group of flexible electrode sheets is respectively connected to the capacitance measurement module by wires, thereby realizing the detection of four groups of capacitance changes. The present invention has the characteristics of arbitrary force direction, simple structure and simple calculation process.

Description

Technical Field

[0001] The invention belongs to the field of measurement, and in particular relates to an annular device and a measurement method capable of measuring the magnitude, direction and action point of multi-dimensional forces. Background Art

[0002] With the progress of science and technology and the rapid development of society, automation equipment plays an increasingly important role in all aspects of social production. For example, the current automated production workshop is developing towards unmanned operation, and all industrial manufacturing processes rely on sensors to perceive the external environment and guide the control system to make judgments. Another example is the tactile sensors currently installed on the surface of the robot skin or robot gripper, which are used to contact the target object and perceive the physical properties of the target object. The robot arm grasps and releases the workpiece through intelligent multi-dimensional perception, and smoothly transfers the fragile workpiece to the next station. Therefore, the detection and perception of the size, direction, and point of action of multi-dimensional forces is crucial. Currently, most sensors used to detect force are three-dimensional flexible sensors and six-dimensional force / torque sensors. They can only detect forces or torques in the x, y, and z directions, and cannot detect arbitrary forces and torques, which has certain limitations. Secondly, force decoupling is currently mostly mechanical decoupling and performed through algorithms. Mechanical decoupling often requires complex mechanical mechanisms to cooperate. When calculating forces in a certain direction, other forces are mechanically compensated. The complex structure makes the application scope of this sensor relatively limited and only applicable to rigid bodies. Although the calculation results of decoupling using intelligent algorithms are more accurate, the calculation process is cumbersome and requires the operation of high-computing-power computers, which greatly increases the cost of use. Therefore, how to design a device that can perceive the size, direction, and point of action of multi-dimensional forces and a simple decoupling measurement method, while ensuring the accuracy of the measurement results of the flexible body and the arbitrariness of the measurement range, and ensuring the simplicity of the structure, is the key to achieving widespread application of multi-dimensional force sensors.

[0003] Based on the above problems, the present invention proposes an annular device and a measurement method that can sense the size, direction, and point of action of multi-dimensional forces. The device sets a hemispherical elastic body as a force-bearing body to ensure that the force-bearing points can be approximated as a plane tangent to the outer spherical surface, eliminating the influence of the torque of the Z axis; four capacitors composed of four groups of flexible electrodes are set to ensure dynamic detectability under different forces, and the size, direction, and point of action of the force are decoupled according to the four groups of data; the connecting elastic ribs are set to ensure that the deformation of the connecting elastic ribs is different under different forces, so that the four capacitors produce different capacitance values. The realization of the above parts enables the present invention to utilize the detection of capacitance on a symmetrical elastic body, so that the entire annular device has the characteristics of arbitrariness of the force direction, simple structure, and simple calculation process. It solves the problems of limitations of existing sensors in detecting force direction, complex structure, and cumbersome algorithms. Summary of the invention

[0004] In order to solve the above problems, the purpose of the present invention is to provide a device with accurate results, strong arbitrary measurement range and simple structure.

[0005] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is: an annular device capable of measuring the magnitude, direction and action point of multi-dimensional force, characterized in that it comprises an outer ring elastic body, an inner cylindrical elastic body, connecting elastic ribs, flexible electrodes, a hemispherical elastic body and a capacitance measurement module; the bottom surface of the outer ring elastic body is fixed, the inner cylindrical elastic body is floating, the outer ring elastic body and the inner cylindrical elastic body are connected by four connecting elastic ribs, and the four connecting elastic ribs are arranged in a cross shape between the outer ring elastic body and the inner cylindrical elastic body, so as to realize the multi-dimensional movement of the inner cylindrical elastic body when subjected to force; the flexible electrodes are divided into four Groups, each group includes two flexible electrode sheets of the same size, the flexible electrode sheets are respectively attached to the inner surface of the outer ring elastomer and the outer surface of the inner cylindrical elastomer, so as to ensure that the direction and angle of the flexible electrode sheets and the inner cylindrical elastomer are consistent when they move; the lower surface of the hemispherical elastomer and the upper surface of the inner cylindrical elastomer are concentrically connected, so as to continuously transmit the force applied to the hemispherical elastomer to the inner cylindrical elastomer; the flexible electrode sheets are respectively connected to the capacitance measurement module by wires, and each group of the flexible electrodes constitutes a capacitor, so as to detect the change of the capacitance value of the capacitor.

[0006] Further, preferably, the capacitance measurement module includes a measurement PCB board, a wire wrapped in aluminum foil, and an LCR tester. The measurement PCB board is composed of two multi-way selection chips CD4051BE, and has a total of four groups of input ends, each group of the input ends has two ports, which are respectively connected to a group of flexible electrode sheets. The measurement PCB board has a total of two output ends, which are respectively connected to the two ends of the LCR tester. Through the rapid switching of different paths by the multi-way selection chip CD4051BE, it is finally ensured that the measurement of the capacitance value of each capacitor is completed at the same time.

[0007] Further, preferably, the height of the inner cylindrical elastomer is smaller than the height of the outer ring elastomer, the diameter of the inner cylindrical elastomer is smaller than the diameter of the outer ring elastomer, and the length of the flexible electrode along the height direction is equal to the height of the inner cylindrical elastomer.

[0008] A method for measuring the magnitude, direction and action point of multi-dimensional force, comprising the following steps:

[0009] Step (1) Leading out the flexible electrode with the wire wrapped with the aluminum foil to achieve electric field shielding and ensure that the capacitance value obtained by the test is not disturbed;

[0010] Step (2) fixing the outer ring elastic body on the test platform to ensure that the inner cylindrical elastic body generates relative displacement in space relative to the outer ring elastic body under pressure, so that the connecting elastic ribs generate different deformations in space to achieve the conversion of force into deformation;

[0011] Step (3) applying a force F in any direction to the hemispherical elastic body;

[0012] Step (4) connects the capacitance measurement modules to the flexible electrodes for actual measurement. The capacitance values ​​of the four capacitors can be obtained by the LCR tester, and the capacitance change value caused by the deformation is obtained to realize the conversion from deformation to capacitance value. The capacitance change in the vertical direction caused by the applied force F is and the average displacement change in the horizontal direction s It can be obtained by the following formula:

[0013]

[0014]

[0015] The angle between the applied force F and the xy plane , the angle between the force F applied to the xy plane and the x-axis and the vertical capacitance change caused by the applied force F The relationship is:

[0016]

[0017] in: is the dielectric constant of the air between the plates, is the radius of the inner cylindrical elastic body, is the radius of the outer ring elastic body, b is the width of the connecting elastic rib, a is the length of the connecting elastic tendon along the radial direction, E is the elastic modulus of the connecting elastic tendon, I is the moment of inertia of the connecting elastic tendon, is the height of the flexible electrode, is the angle between any point on the flexible electrode and the x-axis in the force direction, s is the average displacement change in the horizontal direction caused by the applied force F.

[0018] Beneficial effects of the present invention:

[0019] 1. The present invention utilizes a simple integrated structural design and decoupling of multiple groups of capacitive sensors to achieve the resolution of direction and the magnitude and direction of applied force.

[0020] 2. The structure involved in the present invention can accept forces in any direction on the upper horizontal plane, and solves the limitation that the multi-dimensional sensor can only sense forces in three-axis directions through the spherical structure.

[0021] 3. The decoupling method involved in the present invention adopts a method of converting force into deformation, and then into capacitance change, avoiding complex decoupling methods and reducing a large number of calculation processes. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural schematic diagram of the present invention;

[0023] Figure 2 It is a front view of the present invention;

[0024] Figure 3 A top view of the present invention;

[0025] Figure 4 is a schematic diagram of a capacitance measurement module of the present invention;

[0026] Among them: a hemispherical elastic body 1, an outer ring elastic body 2, an inner cylindrical elastic body 3, a connecting elastic rib 4, a flexible electrode 5, and a capacitance measurement module 6. DETAILED DESCRIPTION

[0027] The present invention is described in detail below in conjunction with the accompanying drawings. However, it should be understood that the accompanying drawings are provided only to help those skilled in the art further understand the present invention, but do not limit the present invention in any form. like Figure 1-Figure 4As shown, the present invention provides an annular device capable of measuring the magnitude, direction and action point of multi-dimensional force, characterized in that it comprises an outer ring elastic body 2, an inner cylindrical elastic body 3, connecting elastic ribs 4, flexible electrodes 5, a hemispherical elastic body 1 and a capacitance measurement module 6; the bottom surface of the outer ring elastic body 2 is fixed, the inner cylindrical elastic body 3 is floating, the outer ring elastic body 2 and the inner cylindrical elastic body 3 are connected via four connecting elastic ribs 4, the four connecting elastic ribs 4 are arranged in a cross shape between the outer ring elastic body 2 and the inner cylindrical elastic body 3, and are used to realize the multi-dimensional movement of the inner cylindrical elastic body 3 when subjected to force; the flexible electrodes 5 are divided into four groups, Each group includes two flexible electrode sheets of the same size, which are respectively attached to the inner surface of the outer ring elastomer 2 and the outer surface of the inner cylindrical elastomer 3, so as to ensure that the direction and angle of the flexible electrode sheet and the inner cylindrical elastomer 3 remain consistent during movement; the lower surface of the hemispherical elastomer 1 and the upper surface of the inner cylindrical elastomer 3 are concentrically connected, so as to continuously transmit the force applied to the hemispherical elastomer 1 to the inner cylindrical elastomer 3; the flexible electrode sheets are respectively connected to the capacitance measurement module 6 by wires, and each group of the flexible electrodes 5 constitutes a capacitor, so as to detect changes in the capacitance value of the capacitor.

[0028] The capacitance measurement module 6 described in the present invention includes a measurement PCB board, a wire wrapped in aluminum foil, and an LCR tester. The measurement PCB board is composed of two multi-way selection chips CD4051BE, and has a total of four groups of input ends. Each group of the input ends has two ports, which are respectively connected to a group of flexible electrode sheets. The measurement PCB board has a total of two output ends, which are respectively connected to the two ends of the LCR tester. Through the fast switching of different paths by the multi-way selection chip CD4051BE, it is finally ensured that the measurement of the capacitance value of each capacitor is completed at the same time.

[0029] The height of the inner cylindrical elastomer 3 described in the present invention is smaller than the height of the outer ring elastomer 2, the diameter of the inner cylindrical elastomer 3 is smaller than the diameter of the outer ring elastomer 2, and the length of the flexible electrode 5 along the height direction is equal to the height of the inner cylindrical elastomer 3.

[0030] A method for measuring the magnitude, direction and action point of multi-dimensional force, characterized by comprising the following steps:

[0031] Step (1) Leading out the flexible electrode 5 with the wire wrapped with the aluminum foil to achieve electric field shielding and ensure that the capacitance value obtained by the test is not disturbed;

[0032] Step (2) fix the outer ring elastic body 2 on the test platform to ensure that the inner cylindrical elastic body 3 generates relative displacement in space relative to the outer ring elastic body 2 under pressure, so that the connecting elastic rib 4 generates different deformations in space to achieve the conversion of force into deformation;

[0033] Step (3) applying a force F in any direction to the hemispherical elastic body 1;

[0034] Step (4) The capacitance measurement module 6 is connected to the flexible electrode 5 for actual measurement. The capacitance values ​​of the four capacitors can be obtained by the LCR tester, and the capacitance change value caused by the deformation is obtained to realize the conversion from deformation to capacitance value. The capacitance change in the vertical direction caused by the applied force F is and the average displacement change in the horizontal direction s It can be obtained by the following formula:

[0035]

[0036]

[0037] The angle between the applied force F and the xy plane , the angle between the force F applied to the xy plane and the x-axis and the vertical capacitance change caused by the applied force F The relationship is:

[0038]

[0039] in: is the dielectric constant of the air between the plates, is the radius of the inner cylindrical elastic body 3, is the radius of the outer ring elastic body 2, b is the width of the connecting elastic rib 4, a is the length of the connecting elastic rib 4 along the radial direction, E is the elastic modulus of the connecting elastic rib 4, I is the moment of inertia of the connecting elastic rib 4, is the height of the flexible electrode 5, is the angle between any point on the flexible electrode 5 and the x-axis in the force direction, s is the average displacement change in the horizontal direction caused by the applied force F.

[0040] The magnitude, direction, and point of action of multidimensional forces can be obtained by the following methods:

[0041] During the measurement, the changes in the capacitance values ​​of the four capacitors can be considered to be caused by the changes in the area facing the flexible electrodes 5 in the vertical direction and the changes in the distance between the flexible electrodes 5 in the horizontal direction;

[0042] The expressions for the four capacitors are:

[0043]

[0044]

[0045]

[0046]

[0047] The capacitance change caused in the horizontal direction can be converted into:

[0048]

[0049]

[0050] Average displacement change due to horizontal force s The capacitance after is:

[0051]

[0052]

[0053] pass and The expression can be obtained and s The value of

[0054] The force F of any size, direction, and point of application is decomposed along the x, y, and z axes at the center of gravity into:

[0055]

[0056]

[0057]

[0058] in That is, the angle between the force in any direction and the xoy plane. That is, the angle between the force decomposed into the xoy plane and the x-axis;

[0059] The change in displacement is:

[0060]

[0061] A pair of flexible electrodes 5 face the angle for:

[0062]

[0063] so In range It can be expressed as:

[0064]

[0065] If only the distance change caused by the horizontal plane x and y is considered, the deformation of the elastic connecting bar caused by the force in the x-axis direction is for:

[0066]

[0067]

[0068] The xy coordinate axis is established on the horizontal plane, and the equation of the outer circle curve of the inner cylindrical elastic body 3 after the change can be listed as:

[0069]

[0070] Will and Substituting the above formula into the polar coordinate equation, we get:

[0071]

[0072] in:

[0073]

[0074] The distance between the arcs is ;

[0075] The change in average distance caused by the forces in the x and y directions is:

[0076]

[0077]

[0078] The expression for cylindrical capacitance is:

[0079]

[0080] It can be expressed as:

[0081]

[0082] and The value of can be obtained by the following formula:

[0083]

[0084] Therefore it is known The value of can be solved to and The value of

[0085] Since the force-bearing surface is a sphere, no torque is generated around the Z axis, that is, ;

[0086] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essence of the present invention. In the absence of conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. A method for measuring a ring-shaped device capable of measuring the magnitude, direction, and action point of multi-dimensional forces, characterized in that: The annular device capable of measuring the magnitude, direction and point of action of multi-dimensional forces comprises an outer ring elastic body, an inner cylindrical elastic body, connecting elastic ribs, a flexible electrode sheet, a hemispherical elastic body and a capacitance measurement module; the bottom surface of the outer ring elastic body is fixed, the inner cylindrical elastic body is floating, the inner cylindrical elastic body is connected to the outer ring elastic body through four connecting elastic ribs, and the upper surfaces of the three are all in the same horizontal plane; the connecting elastic ribs and the inner cylindrical elastic body are in the shape of equal height strips, and are arranged in a cross shape between the outer ring elastic body and the inner cylindrical elastic body, so as to realize the multi-dimensional movement of the inner cylindrical elastic body when subjected to force; The flexible electrodes are divided into four groups, each group includes two flexible electrode sheets of the same size, the flexible electrode sheets are respectively attached to the inner surface of the outer ring elastic body and the outer surface of the inner cylindrical elastic body, so as to achieve the consistency of direction and angle of the flexible electrode sheet and the inner cylindrical elastic body when they move; the lower surface of the hemispherical elastic body and the upper surface of the inner cylindrical elastic body are concentrically connected, so as to achieve the continuous transmission of the force applied to the hemispherical elastic body to the inner cylindrical elastic body; the flexible electrode sheets are respectively connected to the capacitance measurement module by wires, and each group of the flexible electrode sheets constitutes a capacitor, so as to achieve the detection of the change of the capacitance value of the capacitor; Based on the annular device capable of measuring the magnitude, direction and action point of multi-dimensional forces, the measuring method capable of measuring the magnitude, direction and action point of multi-dimensional forces mainly comprises the following steps: Step (1) Leading out the flexible electrode sheet with a wire wrapped with aluminum foil to achieve electric field shielding and ensure that the capacitance value obtained by the test is not disturbed; Step (2) fixing the outer ring elastic body on the test platform to ensure that the inner cylindrical elastic body generates relative displacement in space relative to the outer ring elastic body under pressure, so that the connecting elastic ribs generate different deformations in space to achieve the conversion of force into deformation; Step (3) applying a force F in any direction to the hemispherical elastic body; Step (4) connects the capacitance measurement modules to the flexible electrode sheets for actual measurement. The capacitance values ​​of the four capacitors can be obtained by an LCR tester to obtain the capacitance change value caused by deformation, which is used to realize the conversion from deformation to capacitance value. The capacitance change of the inner cylindrical elastic body in the vertical direction caused by applying force F to the hemispherical elastic body is and the average displacement change in the horizontal direction s It can be obtained by the following formula: pass and The expression can be obtained and s The value of; the angle between the applied force F and the xy plane , the angle between the force F applied to the xy plane and the x-axis , the change in capacitance in the vertical direction caused by the applied force F The relationship is: If only the distance change caused by the horizontal plane x and y is considered, the deformation amount of the connecting elastic tendon caused by the force in the x-axis direction is for: Establishing an xy coordinate axis on the horizontal plane, the equation of the outer circle curve of the inner cylindrical elastic body after the change can be listed as: Will and Substituting the above formula into the polar coordinate equation, we get: in: The change in average distance caused by the forces in the x and y directions is: The distance between arcs is expressed as: ; in: is the dielectric constant of the air between the plates, is the radius of the inner cylindrical elastic body, is the radius of the outer ring elastic body, b is the width of the connecting elastic rib, a is the length of the connecting elastic rib along the radial direction, E is the elastic modulus of the connecting elastic rib, I is the moment of inertia of the connecting elastic rib, is the height of the flexible electrode sheet, is the angle between any point on the flexible electrode sheet and the x-axis in the force direction, s is the average displacement change in the horizontal direction caused by the applied force F.

2. The measuring method of the annular device capable of measuring the magnitude, direction and action point of multi-dimensional force according to claim 1, characterized in that: In the annular device capable of measuring the magnitude, direction and point of action of multi-dimensional forces, the height of the inner cylindrical elastic body is smaller than the height of the outer ring elastic body, the diameter of the inner cylindrical elastic body is smaller than the diameter of the outer ring elastic body, and the length of the flexible electrode sheet along the height direction is equal to the height of the inner cylindrical elastic body.

3. The measuring method of the annular device capable of measuring the magnitude, direction and action point of multi-dimensional force according to claim 1, characterized in that: The capacitance measurement module includes a measurement PCB board and a wire wrapped in aluminum foil; the measurement PCB board is composed of two multi-channel selection chips CD4051BE, and has four groups of input ends, each group of input ends has two ports, which are respectively connected to a group of flexible electrode sheets; the measurement PCB board has two output ends, which are respectively connected to the two ends of the LCR tester; the multi-channel selection chip CD4051BE quickly switches different paths, and finally ensures that the measurement of the capacitance value of each capacitor is completed at the same time.

Images