Torque sensor module

Abstract

The present invention relates to a torque sensor module, and provides a method for pre-acquiring a calibration gain for a strain gauge of a torque sensor module in order to precisely sense force and torque on one axis or more than multiple axes and enable precise control of robot joints such as robot arms, necks, and wrists, and a torque sensor module in which the calibration gain is applied and torque control of a robot joint can be performed.

Description

Technical Field

[0001] The present invention relates to a torque sensor module, and more particularly, to a torque sensor module that pre-acquires a calibration gain for a strain gauge of a designed torque sensor module and applies it to torque control.

Background Art

[0002] In the case of industrial robots, generally, a torque sensor in a form that can be mounted on a robot joint or the like is used to measure the force applied by a mechanism mounted on a robot arm to a work target. The method of mounting a torque sensor on a robot joint for measurement has complex dynamics analysis and errors may accumulate, and it has been studied more recently in the field of intelligent service robots than in industrial robots.

[0003] When a robot arm or other part collides with an external object or person, it is impossible to sense it, and there is a problem that it is difficult to ensure safety through active countermeasures. Most intelligent robots for current various services are not well-known and have to work in an uncontrolled environment, so the safety of robots and people must be considered more preferentially than that of industrial robots and they must operate. For example, despite the influence of crosstalk such as the force (Bending Force) applied or collided by a person, in a robot arm or the like, it may be necessary to precisely control by sensing the rotational force with respect to one axis in a Cartesian coordinate system, that is, the z-axis torque Tz on the xy plane. In some cases, it may also be necessary to precisely control by sensing multi-axis forces and torques in various directions such as the neck and wrist.

[0004] Therefore, it is intended to propose a torque sensor module that enables sensing of forces and torques at a robot joint and precise control of the robot.

[0005] Related prior art documents include patent application number 10-2009-0115343 (November 26, 2009), etc. [Prior art documents] [Patent Documents]

[0006] Republic of Korea Patent Application No. 10-2009-0115343 (November 26, 2009) [Overview of the project] [Problems that the invention aims to solve]

[0007] Therefore, the present invention was derived to solve the above-mentioned problems, and the object of the present invention is to provide a method for pre-acquiring a calibration gain for a strain gauge of a torque sensor module in order to precisely sense force and torque on one axis or more than multiple axes and enable precise control of robot joints such as robot arms, necks, and wrists, and a torque sensor module in which the calibration gain is applied to the torque sensor module and which is capable of performing torque control of robot joints.

[0008] Other objects of the present invention will become more clear based on the preferred embodiments described below. [Means for solving the problem]

[0009] First, to summarize the features of the present invention, in an apparatus for analyzing the operation of a torque sensor module according to one aspect of the present invention for achieving the above objective, the calibration method may include: receiving sensing voltages from a plurality of strain gauges mounted on the torque sensor module with respect to an input torque, and receiving each sensing voltage from each contact in which a pair of strain gauges mounted at each of a number of positions are connected in series; calculating a difference component including a first difference value between a reference voltage and each of the sensing voltages, and a second difference value for each of two combinations of the sensing voltages; calculating a calibration gain corresponding to the input torque and the difference component; and applying the calibration gain to the circuit of the torque sensor module so as to calculate the torque received by the torque sensor module in the circuit of the torque sensor module according to the calibration gain.

[0010] The input torque may include forces with respect to the three axes of the Cartesian coordinate system, and values ​​for one or more of the forces or torques with respect to the three axes.

[0011] In the step of calculating the calibration gain, the calibration gain is calculated such that the formula '(T - AS)=k' is satisfied, where T is the input torque, A is the calibration gain, S is the difference component, and k may be 0 or a predetermined real value for calibration.

[0012] The calibration gain can be determined according to the results of regression analysis or neural network learning, while changing the value of the input torque, so that the calibration gain has a predetermined minimum value.

[0013] Furthermore, a torque sensor module circuit according to another aspect of the present invention includes: a reference voltage generation unit; a memory for storing calibration gains; a torque detection unit that receives sensing voltages from a plurality of strain gauges mounted on the torque sensor module, receives each sensing voltage from each contact in which a pair of strain gauges mounted at each of a number of positions are connected in series, calculates a difference component including a first difference value between the reference voltage from the reference voltage generation unit and each of the sensing voltages, and a second difference value for each of the two combinations of the sensing voltages, and calculates a torque corresponding to the difference component and the calibration gain; and a torque control unit that generates a command for torque control based on the calculated torque, wherein the calibration gain may be pre-calculated for each of the sensing voltages in the torque sensor module for a predetermined input torque, corresponding to the input torque and the difference component, and stored in the memory.

[0014] The torque sensor module, as an example, comprises a body in which a first sensitivity adjustment hole, a strain measurement hole, a second sensitivity adjustment hole, and a stiffness adjustment hole are repeatedly formed along the circumferential direction between a central hole and an outer circumferential surface; and the strain measurement hole, to which the pair of strain gauges are attached, may have a trapezoidal shape in which the side toward the center is longer than the side toward the outer circumferential surface. [Effects of the Invention]

[0015] According to the torque sensor module of the present invention, by combining six strain gauges, the calibration gain for the strain gauges of the torque sensor module, which is designed using three full-bridge configurations and three half-bridge configurations, can be obtained in advance. By applying the calibration gain thus obtained to the torque sensor module, force and torque on one axis or even more axes can be precisely sensed, enabling precise control of robot joints such as robot arms, necks, and wrists.

[0016] As a result, it becomes possible to embody a high-performance torque sensor module by precisely applying the sensor information of the strain gauge. For example, it can assist in precisely controlling the rotational force on the xy plane, that is, the z-axis torque Tz, despite the influence of crosstalk such as the force (z-axis bending force) applied or collided with by a person. In some cases, it can be applied to a torque sensor module of a robot joint where multi-axis (for example, 6-axis) forces and torques such as the neck and wrist are controlled, and can assist in precisely controlling forces and torques.

[0017] The accompanying drawings, which are included as a part of the detailed description to assist in understanding the present invention, provide examples of embodiments of the present invention and explain the technical idea of the present invention together with the detailed description.

Brief Description of the Drawings

[0018] [Figure 1] It is an exemplary perspective view of a torque sensor module 100 according to an embodiment of the present invention. [Figure 2] It is a front view of the torque sensor module 100 of FIG. 1. [Figure 3] It is a diagram for explaining the connection state of the strain gauges {(SG1, SG2), (SG3, SG4), (SG5, SG6)} of the present invention. [Figure 4] It is a flowchart for explaining a calibration method in an apparatus for analyzing the operation of a torque sensor module 100 according to an embodiment of the present invention. [Figure 5] It shows the multi-axis direction components of the force or torque received by the torque sensor module 100 of the present invention. [Figure 6] It is a block diagram of the circuit configuration of the torque sensor module 100 of the present invention.

Modes for Carrying Out the Invention

[0019] Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. At this time, the same components in each drawing are denoted by the same reference numerals as much as possible. In addition, detailed descriptions of functions and / or configurations that are already known are omitted. The content disclosed below focuses on the parts necessary for understanding the operations according to various embodiments, and descriptions of elements that may obscure the gist of the description are omitted. Furthermore, some components in the drawings may be shown exaggeratedly, omitted, or schematically. The size of each component does not fully reflect the actual size, and therefore, the content described in this specification is not limited by the relative size or interval of the components depicted in each drawing.

[0020] In describing embodiments of the present invention, if it is determined that a specific description of the known art related to the present invention may unnecessarily obscure the gist of the present invention, the detailed description thereof is omitted. And the terms described below are terms defined in consideration of the functions in the present invention, and these may vary depending on the intention or convention of the user, operator, etc. Therefore, the definition should be determined based on the content of the entire specification. The terms used in the detailed description are merely for describing embodiments of the present invention and should never be limiting. Unless otherwise specified, the singular form includes the plural meaning. In this specification, expressions such as "including" or "comprising" are used to refer to a certain characteristic, number, step, operation, element, part thereof, or combination, and should not be construed as excluding the existence or possibility of one or more other characteristics, numbers, steps, operations, elements, part thereof, or combination in addition to those described.

[0021] Furthermore, terms such as first, second, etc. can be used to describe various components, but the components are not limited by the terms, and the terms are used only for the purpose of distinguishing one component from another.

[0022] FIG. 1 is an exemplary perspective view of a torque sensor module 100 according to an embodiment of the present invention. FIG. 2 is a front view of the torque sensor module 100 of FIG. 1.

[0023] Referring to Figures 1 and 2, a torque sensor module 100 according to one embodiment of the present invention may include a circular body 110 having a predetermined thickness, a pair of strain gauges {(SG1, SG2), (SG3, SG4), (SG5, SG6)} mounted in each of the multiple strain measurement holes 112 of the body 110, and a circuit board 130 connected to the signal lines from each strain gauge pair {(SG1, SG2), (SG3, SG4), (SG5, SG6)} mounted in each of the multiple strain measurement holes 112. Here, it is preferable that there are three pairs of strain gauges {(SG1, SG2), (SG3, SG4), (SG5, SG6)}, but if necessary, further strain measurement holes 112 may be provided, and further strain gauge pairs mounted therein may be provided.

[0024] The circuit board 130 is manufactured in the form of a ring-shaped PCB (Printed Circuit Board) as illustrated in the drawing, and can be mounted on either side of the body 110. The circuit board 130 is manufactured so that no part of it gets caught in the hole 119 in the center of the body 110, and can be mounted on a predetermined axis in a Cartesian coordinate system, i.e., a robot arm or the like that is intended to sense and control z-axis torque Tz, via the hole 119 in the center of the body 110. The circuit board 130 can be equipped with circuit components such as an amplifier for digitally processing the sensing signals from the signal lines of each strain gauge {(SG1, SG2), (SG3, SG4), (SG5, SG6)} to calculate torque values, an AD (Analog to Digital) converter, and a calculation unit.

[0025] Here, an exemplary structure of a torque sensor module 100 according to one embodiment of the present invention will be described, but it should be made clear in advance that this is merely an exemplary description, and the structure of the body 110 and the multiple strain measurement holes 112 and other holes in the body 110 may have various patterns and shapes.

[0026] As shown in Figures 1 and 2, the body 110 includes a first sensitivity adjustment hole 111, a strain measurement hole 112, a second sensitivity adjustment hole 113, and a stiffness adjustment hole 114 along the circumferential direction between the central hole 119 and the outer circumferential surface, and the first sensitivity adjustment hole 111, strain measurement hole 112, second sensitivity adjustment hole 113, and stiffness adjustment hole 114 are formed in sequence two or more times.

[0027] The rigidity adjustment holes 114 are formed one or more times between the second sensitivity adjustment hole 113 and the first sensitivity adjustment hole 111, and can be formed in an appropriate number so as to appropriately reduce the overall weight while maintaining the rigidity of the sensor module 100.

[0028] A first sensitivity adjustment hole 111 and a second sensitivity adjustment hole 113 are formed on both sides of the strain measurement hole 112 in the circumferential direction, at a predetermined distance from the strain measurement hole 112. Multiple stiffness adjustment holes 114 can be formed at positions spaced apart with a predetermined pitch in the circumferential direction. The holes at both ends of the stiffness adjustment holes 114 can also be formed to be spaced apart from the first sensitivity adjustment hole 111 or the second sensitivity adjustment hole 113 by a predetermined distance.

[0029] Each strain measurement hole 112 is a hole for mounting a pair of strain gauges {(SG1, SG2), (SG3, SG4), (SG5, SG6)} for measuring the strain applied to the torque sensor module 100 at the position where the torque sensor module 100 is installed. As shown in the figure, one pair of strain gauges {(SG1, SG2), (SG3, SG4), (SG5, SG6)} is mounted on each side wall of each strain measurement hole 112, that is, on both side walls in the circumferential direction, facing each other.

[0030] The first sensitivity adjustment holes 111 and the second sensitivity adjustment holes 113, which are symmetrically formed one on each side of the strain measurement hole 112, are preferably formed at predetermined distances from the strain measurement hole 112 in the circumferential direction, and are formed to an appropriate size so that the strain gauges {(SG1, SG2), (SG3, SG4), (SG5, SG6)} can generate a sensing signal that measures an appropriate deformation rate (or deformation) at that position.

[0031] In addition, it is advantageous for measuring the deformation rate of each strain gauge {(SG1, SG2), (SG3, SG4), (SG5, SG6)} if the strain measurement hole 112 is formed in a trapezoidal shape with the central side having a longer length than the outer peripheral side. The sensitivity of each strain gauge {(SG1, SG2), (SG3, SG4), (SG5, SG6)} may vary depending on its position, the distance between the first sensitivity adjustment hole 111 and the second sensitivity adjustment hole 113, and the size of the holes. Therefore, the distance between the first sensitivity adjustment hole 111 and the second sensitivity adjustment hole 113 and the size of the holes should be formed to an appropriate distance and size according to the purpose, and it is preferable that the inclination of both side walls in the circumferential direction of the trapezoidal shape to which the strain gauges {(SG1, SG2), (SG3, SG4), (SG5, SG6)} are attached is also formed to have an appropriate symmetrical inclination.

[0032] Although the first sensitivity adjustment hole 111, the second sensitivity adjustment hole 113, and the rigidity adjustment hole 114 are shown as circular in example form, they are not limited to this and can be formed in a variety of shapes, such as circles, ellipses, trapezoids, triangles, squares, pentagons, and other polygons.

[0033] The rigidity adjustment holes 114 can be formed at positions spaced apart so as to have a predetermined pitch in the circumferential direction. The number of rigidity adjustment holes 114 can be formed between the second sensitivity adjustment hole 113 and the first sensitivity adjustment hole 111 in an appropriate number with an appropriate size and spacing distance so as to maintain a predetermined rigidity. The formation of the rigidity adjustment holes 114 in the present invention is not in the conventional form (patent application no. 10-2009-0115343) which is formed by spokes in the shape of a wheel spoke (with a relatively large number of holes between the spokes), but rather the holes are formed on a surface that extends to the outer circumferential surface of the body 110 itself (with spokes between the holes, so the area of ​​the spokes in the shape of a wheel spoke is larger than in the conventional form), so the rigidity can be increased so as to maintain the shape of the torque sensor module 100 better than the shape of a wheel spoke.

[0034] Furthermore, as shown in Figures 1 and 2, it is preferable that the centers of the first sensitivity adjustment hole 111, the second sensitivity adjustment hole 113, and the rigidity adjustment hole 114 are located on the same first distance r1 from the center O of the body 110. This ensures that deformation rate sensor information is provided in a balanced manner for deformation from any direction.

[0035] The trapezoidal strain measurement holes 112 may be formed such that their centers lie on the same first distance r1 from the center O, i.e., on the same arc relative to the center O, as the first sensitivity adjustment holes 111, the second sensitivity adjustment holes 113, and the stiffness adjustment holes 114. However, the strain measurement holes 112 may be arranged such that at least a portion of the area (the space inside the hole), excluding the four sides of the trapezoidal shape, crosses the arc relative to the center O at the first distance r1.

[0036] Furthermore, the sensitivity of each strain gauge {(SG1, SG2), (SG3, SG4), (SG5, SG6)} may vary depending on where they are positioned on the side walls of the strain measurement hole 112. For example, if the trapezoidal strain measurement hole 112 is formed such that its center lies at the same first distance r1 from the center O, i.e., on the same arc relative to the center O, as is the case with the first sensitivity adjustment hole 111, the second sensitivity adjustment hole 113, and the stiffness adjustment hole 114, then each strain gauge {(SG1, SG2), (SG3, SG4), (SG5, SG6)} may have its bottom surface (mounting surface) center lies at the same first distance r1 from the center O. However, it is preferable that the strain gauges {(SG1, SG2), (SG3, SG4), (SG5, SG6)} are positioned such that the center of their bottom surface (attachment surface) is located at a distance smaller than the first distance r1 within the trapezoidal hole. This is because the strain gauges {(SG1, SG2), (SG3, SG4), (SG5, SG6)} are positioned closer to the sensitivity adjustment holes 111 and 113, which is advantageous for sensing the rate of deformation.

[0037] In Figures 1 and 2, the stiffness adjustment holes 114 can be formed in an appropriate number to appropriately reduce the overall weight while maintaining the stiffness of the torque sensor module 100. Furthermore, an appropriate number of holes 150 can be formed on an extra surface of the body 110 at another second distance r2 from the center O to further reduce the weight, and an appropriate number of holes 160 can be further formed on an extra surface of the body 110 at yet another third distance r3 from the center O. Such holes 111, 112, 113, 114, 150, and 160 can also be used to install cables for connection to the circuit board 130 and cables and components for connection to other accessories that make up the robot.

[0038] In particular, the torque sensor module 100 of the present invention allows for the pre-acquisition of a calibration matrix (or gain) (A) for the strain gauges {(SG1, SG2), (SG3, SG4), (SG5, SG6)} of the torque sensor module 100, which is designed using three full-bridge configurations and three half-bridge configurations, by combining six strain gauges {(SG1, SG2), (SG3, SG4), (SG5, SG6)}. By applying this acquired calibration matrix (A) to the torque sensor module (100), force and torque on one axis or even more axes can be precisely sensed, enabling precise control of robot joints such as robot arms, necks, and wrists.

[0039] To this end, the strain gauge pairs {(SG1, SG2), (SG3, SG4), (SG5, SG6)} attached to each of the above-mentioned positions on the torque sensor module 100 are connected in series between the first power supply VCC and the second power supply GND, as shown in Figure 3.

[0040] Figure 3 is a diagram illustrating the connected state of the strain gauges {(SG1, SG2), (SG3, SG4), (SG5, SG6)} of the present invention.

[0041] Referring to Figure 3, a first power supply VCC and a second power supply GND are supplied via the circuit board 130. The series connection of each pair of strain gauges {(SG1, SG2), (SG3, SG4), (SG5, SG6)} can be configured such that the connecting wires connected to each terminal of the strain gauges are extended to the circuit board 130 and then electrically connected on the circuit board 130 to form a contact (or center tap), or the connecting wires connected to each terminal of the strain gauges are electrically connected outside the circuit board 130 to form a contact, and then extended and connected to the circuit board 130 to provide the voltage.

[0042] When the torque sensor module 100 is mounted on a robot joint or the like and in operation, the sensing voltages V12, V34, and V56 from each contact of the series-connected strain gauge pairs {(SG1, SG2), (SG3, SG4), (SG5, SG6)} attached to each of these numerous positions are provided to the circuit board 130. The circuit board 130 can perform torque control of the robot based on the sensing voltages V12, V34, and V56 sensed by the strain gauge pairs {(SG1, SG2), (SG3, SG4), (SG5, SG6)}.

[0043] However, before the torque sensor module 100 is mounted on a robot joint or the like and put into operation, the circuit board 130 must have a calibration gain A for the designed or manufactured torque sensor module 100 obtained in advance through an analysis device (not shown) and applied to the circuit of the circuit board 130 so as to appropriately calculate the torque received by the torque sensor module 100 based on the sensing voltage of the strain gauge.

[0044] The above exemplifies how multiple positions for mounting strain gauges {(SG1, SG2), (SG3, SG4), (SG5, SG6)} are mounted on the strain measurement holes 112. However, the structure of the torque sensor module 100 for obtaining such calibration gain A may take various forms, so that the multiple positions for mounting strain gauges {(SG1, SG2), (SG3, SG4), (SG5, SG6)} can be appropriately positioned according to the various structures of the torque sensor module 100. For example, in another embodiment of the present invention, a torque sensor module may also have a pair of strain gauges mounted so that they face each other circumferentially at multiple positions in the circumferential direction of spokes (see Patent Application No. 10-2009-0115343) in the shape of wheel spokes formed on the body 110. In other words, the torque sensor module 100 is not limited to the structure shown in Figures 1 and 2. For torque sensor modules of various structures, a calibration gain A for the designed or manufactured torque sensor module (100) can be obtained in advance through an analysis device (not shown) and applied to the circuit on the circuit board 130 so as to appropriately calculate the torque received by the torque sensor module 100 based on the sensing voltages V12, V34, and V56 of the strain gauge.

[0045] Figure 4 is a flowchart illustrating a calibration method in a device for analyzing the operation of a torque sensor module 100 according to one embodiment of the present invention.

[0046] Referring to Figure 4, the device for analyzing the operation of the torque sensor module 100 (analytical device) may include the steps of: S110 receiving sensing voltages V12, V34, V56 at each contact of strain gauge pairs {(SG1, SG2), (SG3, SG4), (SG5, SG6)} for the input torque T to the torque sensor module 100; S120 calculating the difference component S; S130 calculating the calibration gain A; and S140 applying it to the circuit of the circuit board 130.

[0047] Step S110, which involves receiving the sensing voltages V12, V34, and V56 of each contact, may include receiving the respective sensing voltages V12, V34, and V56 from each contact of a pair of strain gauges {(SG1, SG2), (SG3, SG4), (SG5, SG6)} mounted at various positions on the torque sensor module 100, in a state where they are connected in series.

[0048] The input torque T is the force or torque applied to the torque sensor module 100, and may be the torque applied to the torque sensor module 100 mounted on an actual robot, or the torque applied to the torque sensor module 100 mounted on a test device, etc. If necessary, steps S110 to S140 can be performed on a computer for simulation purposes using a simulated structure of the torque sensor module 100.

[0049] The input torque T can be represented by a matrix as shown in [Equation 1] below. The input torque T can be pre-prepared and applied with predetermined values ​​to enable learning by regression analysis or a neural network, as shown below. The input torque T can include values ​​for one or more forces and torques among the forces and torques on the three axes of a Cartesian coordinate system (see Figure 5). [Mathematics 1] T=[w1, w2, w3, w4, w5, T Z ] T

[0050] Here, the torque value Tz for one of the three axes of the Cartesian coordinate system (for example, the z-axis) may be the target torque value, in which case w1, w2, w3, w4, and w5 are undesirable force or torque components that affect the output of the torque sensor module's torque value, and may be torque components of the other axes (for example, the x and y axes) or force components for each axis (for example, the x, y, and z axes). However, it is not limited to this, meaning that w1, w2, w3, w4, and w5 may be x-axis force component fx, y-axis force component fy, z-axis force component fz, x-axis torque component Tx, and y-axis torque component Ty, respectively. For example, the calibration of the present invention can be performed to obtain the z-axis torque component Tz by setting w1 to w5 as crosstalk and the z-axis torque component Tz as the target torque. Furthermore, in addition to the z-axis torque component Tz, one or more of w1 to w5, i.e., force components or torque components, can also be set to additional meaningful target values ​​for calibration (see Figure 5).

[0051] Next, step S120 for calculating the difference component S may include calculating a difference component S that includes a first difference value VR12, VR34, VR56 between the reference voltage Vref and each of the sensing voltages V12, V34, V56, and difference values ​​V1234, V3456, V1256 for each of the two combinations of the sensing voltages V12, V34, V56.

[0052] The difference component S can be represented by a matrix as shown in [Equation 2] and [Equation 3] below. The difference component S can be calculated based on the respective sensing voltages V12, V34, and V56 for each input of the input torque T, as shown below, in order to perform regression analysis or learning by a neural network. [Math 2] S=[V1234, V3456, V1256, VR12, VR34, VR56] T [Math 3] V1234 = V12 - V34 V3456 = V34 - V56 V1256 = V12 - V56 VR12 = Vref - V12 VR34=Vref-V34 VR56=Vref-V56

[0053] Here, since each sensing voltage V12, V34, and V56 constitutes a half of the Wheatstone bridge, the first difference values ​​VR12, VR34, and VR56 between the reference voltage Vref and each of the sensing voltages V12, V34, and V56 indicate the use of three half-bridges (where strain gauges are placed at two of the four resistors of the bridge), and the second difference values ​​V1234, V3456, and V1256 for each of the two combinations of the sensing voltages V12, V34, and V56 indicate the use of a full Wheatstone bridge (where strain gauges are placed at all of the four resistors of the bridge). Since the method for calculating torque values ​​from the sensing voltage relative to the deformation rate of each strain gauge in a Wheatstone bridge circuit including strain gauge elements is well known, a detailed explanation will be omitted here (see Patent No. 10-2023-0027956 (2023.03.02)).

[0054] Next, step S130 for calculating the calibration gain A may include a step of calculating a calibration gain A corresponding to the input torque T and the difference component S. The calibration gain A can be calculated to satisfy [Equation 4]. [Math 4] (T-AS=k

[0055] Here, k can be the error that should be minimized, and may be set to zero, or it may be any other real value predetermined for calibration.

[0056] In other words, learning is performed while changing the value of the input torque T, and the calibration gain A is determined as shown in [Equation 5] according to the results of learning by regression analysis or a neural network, etc., so that the calibration gain A has the predetermined minimum value k. Here, the neural network may be a CNN (Convolutional Neural Network) or a deep neural network based thereon. For example, in the above example, the input torque T, difference component S, and minimum value k are m=6th order column vectors, and the calibration gain A (or matrix) may be a 6x6 dimension matrix with elements A11 to A66 as shown in [Equation 5]. [Number 5] JPEG2026519481000002.jpg70127

[0057] Next, step S140, which applies to the circuit of the circuit board 130, may include applying the calibration gain A to the circuit of the circuit board 130 so that the torque received by the torque sensor module 100 is calculated in accordance with the calibration gain A. That is, the calibration gain A is stored in a memory such as ROM or RAM of the circuit board 130 and can be used to calculate the torque from the sensing voltages V12, V34, and V56 in the form 'T=AS'.

[0058] The device (analytical device) for analyzing the operation of the torque sensor module 100 of the present invention described above may consist of hardware, software, or a combination thereof. For example, it can be embodied in a server or computing system having at least one processor for performing the above-described functions.

[0059] Such a computing system may include at least one processor, memory, user interface input devices, user interface output devices, storage, and a network interface, all connected via a bus. The processor may be a central processing unit (CPU) or a semiconductor device that performs processing on instruction words stored in memory and / or storage. Memory and storage may include various types of volatile or non-volatile storage media. For example, memory may include ROM (Read Only Memory) and RAM (Random Access Memory).

[0060] Accordingly, the steps of the methods or algorithms described in relation to the embodiments disclosed herein can be directly embodied in hardware, software modules, or a combination thereof, executed by such a processor. The software modules may reside in a storage medium (i.e., memory and / or storage) such as RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disks, removable disks, or CD-ROMs. The exemplary storage medium is coupled to a processor, which can read information from and write information to the storage medium. Alternatively, the storage medium may be integrated with the processor. The processor and storage medium may reside within an ASIC. The ASIC may reside within a user terminal. Alternatively, the processor and storage medium may reside within a user terminal as separate components.

[0061] Figure 6 is a block diagram of the configuration of the circuit board 130 of the torque sensor module 100 of the present invention.

[0062] Referring to Figure 6, the circuit of the circuit board 130 of the torque sensor module 100 of the present invention may include a reference voltage generation unit 610 that generates a reference voltage Vref (for example, VCC / 2 is possible when RA=RB) at the contacts of resistors RA and RB connected in series between a first power supply VCC and a second power supply GND; a memory 620 such as ROM or RAM that stores the calibration gain A; a torque detection unit 630 that calculates the sensing voltages V12, V34, V56 from the strain gauge, the reference voltage Vref, and the torque (in the above formula, 'AS+k' or 'AS') corresponding to the calibration gain A; and a torque control unit 640 that generates a command for torque control based on the torque calculated from the torque detection unit 630.

[0063] For example, the torque detection unit 630 receives sensing voltages from multiple strain gauges attached to the torque sensor module 100, and receives sensing voltages V12, V34, and V56 from each contact of a pair of strain gauges {(SG1, SG2), (SG3, SG4), (SG5, SG6)} attached to each of many positions and connected in series. The torque detection unit 630 calculates a difference component S that includes a first difference value between the reference voltage Vref from the reference voltage generation unit 610 and each sensing voltage V12, V34, and V56, and a second difference value for each of the two combinations of sensing voltages V12, V34, and V56 (see Equations 2 and 3), and can calculate a torque ('AS+k' or 'AS') corresponding to the difference component S and the calibration gain A (see Equation 5) (see Equation 4). The torque detection unit 630 may include an amplifier for receiving the respective sensing voltages V12, V34, and V56, and an ADC (Analog-to-Digital Converter) for converting the analog signal output of the amplifier into a digital signal.

[0064] In other words, as described in the explanation of Figure 4, the calibration gain A is calculated in advance for each sensing voltage V12, V34, and V56 in the torque sensor module 100 for a predetermined input torque T, corresponding to the input torque T and the difference component S, and is stored in the memory 620 for use.

[0065] Here, the torque ('AS+k' or 'AS') calculated by the torque detection unit 630 may have a target torque value Tz for one of the three axes of the Cartesian coordinate system (e.g., the z-axis). Among the components calculated here, w1, w2, w3, w4, w4, and w5 are undesirable force or torque components, and are crosstalk (mutual interference or catch) that affects the output of the torque value of the torque sensor module. These may be torque components of other axes (e.g., x and y axes) or force components for each axis (e.g., x, y, and z axes), and therefore these components can be ignored. However, this is not limited to this; that is, among the components calculated here, w1, w2, w3, w4, and w5 may be x-axis force component fx, y-axis force component fy, z-axis force component fz, x-axis torque component Tx, and y-axis torque component Ty, respectively. For example, it is possible to obtain the target torque Tz by setting w1 to w5 as crosstalk and the z-axis torque component Tz as the target torque. Furthermore, in addition to the z-axis torque component Tz, it is also possible to calculate the torque value by setting one or more of the calculated components w1 to w5, i.e., force components or torque components, to additionally meaningful target values.

[0066] The torque control unit 640 generates commands for torque control of robot joints and the like based on the torque calculated by the torque detection unit 630, enabling precise control of the movement of robot joints and the like.

[0067] As described above, the torque sensor module 100 according to the present invention allows for the pre-acquisition of a calibration matrix (or gain) A for the strain gauges {(SG1, SG2), (SG3, SG4), (SG5, SG6)} of the torque sensor module 100, which is designed using three full-bridge configurations and three half-bridge configurations, by combining six strain gauges {(SG1, SG2), (SG3, SG4), (SG5, SG6)}. By applying this acquired calibration matrix A to the torque sensor module 100, force and torque on one axis or even multiple axes can be precisely sensed, enabling precise control of robot joints such as robot arms, necks, and wrists.

[0068] This enables the implementation of a high-performance torque sensor module 100 by precisely applying sensor information from strain gauges {(SG1, SG2), (SG3, SG4), (SG5, SG6)}, which can assist in the precise control of rotational forces in the xy plane, i.e., z-axis torque Tz, despite the effects of crosstalk, such as forces applied by a person pushing or bumping (z-axis bending force). In some cases, it can be applied to the torque sensor module 100 of robot joints where multi-axis (e.g., 6-axis) forces and torques are controlled, such as in the neck and wrist, to assist in the precise control of forces and torques.

[0069] As described above, the present invention has been explained with specific details such as concrete components, limited embodiments, and drawings. These are provided to aid in a more overall understanding of the invention, and the invention is not limited to the above embodiments. A person with ordinary skill in the art to which the invention belongs can make various modifications and variations without departing from the essential characteristics of the invention. Therefore, the spirit of the invention should not be limited to the described embodiments, and all technical ideas having equivalent or comparable variations to the claims described below should be interpreted as being included within the scope of the rights of the present invention. [Explanation of Symbols]

[0070] SG1, SG2, SG3, SG4, SG5, SG6 strain gauges 610 Reference voltage generation unit 620 memory 630 Torque detection unit 640 Torque Control Unit

Claims

1. In a calibration method for a device that analyzes the operation of a torque sensor module, The steps include: receiving sensing voltages from multiple strain gauges mounted on the torque sensor module in response to an input torque, and receiving the respective sensing voltages from each contact of a pair of strain gauges connected in series at each of a number of locations; A step of calculating a difference component including a first difference value between a reference voltage and each of the sensing voltages, and a second difference value for each of the two combinations of the sensing voltages; A step of calculating a calibration gain corresponding to the input torque and the difference component; The steps include: applying the calibration gain to the circuit of the torque sensor module so that the circuit of the torque sensor module calculates the torque received by the torque sensor module according to the calibration gain; Calibration methods including those mentioned above.

2. The calibration method according to claim 1, wherein the input torque includes a force with respect to three axes of a Cartesian coordinate system and a value for one or more of the forces or torques with respect to the three axes.

3. In the step of calculating the calibration gain, The calibration method according to claim 1, wherein the calibration gain is calculated to satisfy the formula '(T - AS) = k', where T is the input torque, A is the calibration gain, S is the difference component, and k is 0 or a real value predetermined for calibration.

4. The calibration method according to claim 1, wherein the calibration gain is determined according to the results of learning by regression analysis or a neural network, such that the calibration gain has a predetermined minimum value while changing the value of the input torque.

5. Reference voltage generation unit and; The memory that stores the calibration gain; A torque detection unit that receives sensing voltages from multiple strain gauges mounted on a torque sensor module, receives sensing voltages from each contact of a pair of strain gauges connected in series at various locations, calculates a difference component including a first difference value between the reference voltage from the reference voltage generation unit and each of the sensing voltages, and a second difference value for each of the two combinations of the sensing voltages, and calculates a torque corresponding to the difference component and the calibration gain; A torque control unit that generates a command for torque control based on the calculated torque, The calibration gain is calculated in advance for each sensing voltage in the torque sensor module for a predetermined input torque, corresponding to the input torque and the difference component, and stored in the memory of the torque sensor module circuit.

6. The torque sensor module is A body having a first sensitivity adjustment hole, a strain measurement hole, a second sensitivity adjustment hole, and a rigidity adjustment hole repeatedly formed along the circumferential direction between the central hole and the outer surface; The torque sensor module circuit according to claim 5, wherein the strain measuring hole to which the pair of strain gauges are attached has a trapezoidal shape in which the side toward the center is longer than the side toward the outer surface.

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