WO2024242293A1 - Torque sensor module - Google Patents

Abstract

The present invention relates to a torque sensor module. The present invention can provide: a method for obtaining, in advance, a calibration gain for strain gauges of the torque sensor module in order to precisely sense the force and the torque of a single axis, and even multiple axes, and precisely control a robot joint such as that of a robot arm, neck, or wrist; and the torque sensor module capable of controlling the torque of the robot joint by applying the calibration gain to the torque sensor module.

Description

Torque sensor module

The present invention relates to a torque sensor module, and more particularly, to a torque sensor module in which calibration gains for strain gauges of a designed torque sensor module are acquired in advance and applied to torque control.

In the case of industrial robots, torque sensors that can be installed on robot joints, etc., are generally used to measure the force applied by the mechanism mounted on the robot arm to the workpiece. The method of measuring by installing a torque sensor on the robot joint requires complex dynamic analysis and may accumulate errors, so it has been studied more recently in the field of intelligent service robots than in industrial robots.

When a robot arm or other part collides with an external object or person, there is a problem that it is impossible to detect it and it is difficult to secure safety through active response. Since most of the current intelligent robots for various services must perform work in an unknown and uncontrolled environment, the safety of the robot or people must be considered as a top priority even more than in industrial robots. For example, despite the influence of crosstalk such as force (bending force) caused by a person pushing or colliding, in robot arms, etc., there are cases where the rotational force about one axis in a rectangular coordinate system, that is, the z-axis torque (Tz) on the xy plane, must be detected and precisely controlled. In some cases, it may be necessary to detect and precisely control multi-axis forces or torques in various directions such as those of the neck and wrist.

Therefore, we propose a torque sensor module to enable detection of force or torque at robot joints and precise control of the robot.

As related prior literature, reference may be made to Patent Application No. 10-2009-0115343 (November 26, 2009).

Accordingly, the present invention has been made to solve the above-described problems, and an object of the present invention is to provide a method for obtaining calibration gains for strain gauges of a torque sensor module in advance to enable precise detection of force and torque for one axis or more than two axes and 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 to enable torque control of the robot joints.

First, to summarize the features of the present invention, a calibration method in a device for analyzing the operation of a torque sensor module according to one aspect of the present invention for achieving the above purpose may include the steps of: receiving sensing voltages from a plurality of strain gauges mounted on the torque sensor module for an input torque, wherein each sensing voltage is received from each contact point in a state where a pair of strain gauges attached to each of a plurality of positions are connected in series; calculating a differential component including a first differential value between a reference voltage and each of the sensing voltages, and a second differential value for each of two combinations of the sensing voltages; calculating a calibration gain corresponding to the input torque and the differential component; and applying the calibration gain to a circuit of the torque sensor module so that the circuit calculates a torque received by the torque sensor module according to the calibration gain.

The above input torque may include values for one or more of the forces or torques about the three axes of the rectangular coordinate system and the torques about the three axes.

In the step of calculating the above calibration gain, the calibration gain is calculated so as to satisfy the mathematical formula '(T - AS) = k', where T is the input torque, A is the calibration gain, S is the differential component, and k may be 0 or a real number value determined in advance for calibration.

The calibration gain can be determined based on the results of regression analysis or neural network learning so that the calibration gain has a predetermined minimum value while changing the values of the input torque.

And, a torque sensor module circuit according to another aspect of the present invention includes: a reference voltage generator; a memory storing a calibration gain; a torque detection unit which receives sensing voltages from a plurality of strain gauges mounted on the torque sensor module, wherein each sensing voltage is received from each contact point in a state where a pair of strain gauges attached to each of a plurality of positions are connected in series, and calculates a differential component including a first differential value between the reference voltage from the reference voltage generator and each of the sensing voltages, and a second differential value for each of two combinations of the sensing voltages, thereby calculating a torque corresponding to the differential component and the calibration gain; and a torque control unit which generates a command for torque control based on the calculated torque, wherein the calibration gain may be calculated in advance to correspond to the input torque and the differential component for each of the sensing voltages in the torque sensor module for a predetermined input torque and stored in the memory.

The above torque sensor module may include, for example, a body in which a first sensitivity adjustment hole, a strain measuring hole, a second sensitivity adjustment hole, and a stiffness adjustment hole are repeatedly formed along a circumferential direction between a central hole and an outer peripheral surface; and the strain measuring hole to which the pair of strain gauges are attached may have a trapezoidal shape in which a central side has a longer length than an outer peripheral side.

According to the torque sensor module according to the present invention, the calibration gain for the strain gauges of the torque sensor module designed using three full-bridge configurations and three half-bridge configurations through a combination of six strain gauges can be obtained in advance, and by applying the calibration gain obtained in this way to the torque sensor module, the force and torque for one axis or further for multiple axes can be precisely detected, and the precise control of the robot joints such as the robot arm, neck, and wrist can be enabled.

Accordingly, by precisely applying the sensor information of the strain gauge, a high-performance torque sensor module can be implemented, and for example, it can assist in precisely controlling the rotational force in the xy plane, i.e., the z-axis torque (Tz), despite the influence of crosstalk such as a force (z-axis bending force) caused by a person pushing or bumping into it. In some cases, it can be applied to a torque sensor module of a robot joint in which multi-axis (e.g., 6 axes) force or torque is controlled, such as the neck and wrist, to assist in precisely controlling the force or torque.

The accompanying drawings, which are included as a part of the detailed description to aid understanding of the present invention, provide examples of the present invention and, together with the detailed description, explain the technical idea of the present invention.

FIG. 1 is an exemplary perspective view of a torque sensor module (100) according to one embodiment of the present invention.

Figure 2 is a front view of the torque sensor module (100) of Figure 1.

FIG. 3 is a drawing for explaining the connection state of strain gauges {(SG1, SG2), (SG3, SG4), (SG5, SG6)} of the present invention.

FIG. 4 is a flowchart for explaining a calibration method in a device for analyzing the operation of a torque sensor module (100) according to one embodiment of the present invention.

Figure 5 shows the multi-axial direction components of force or torque received from the torque sensor module (100) of the present invention.

Figure 6 is a block diagram of the circuit configuration of the torque sensor module (100) of the present invention.

Hereinafter, the present invention will be described in detail with reference to the attached drawings. At this time, in each drawing, the same components are represented by the same reference numerals as much as possible. In addition, detailed descriptions of functions and/or configurations that are already known will be omitted. The contents disclosed below will focus on parts necessary for understanding operations according to various embodiments, and descriptions of elements that may obscure the gist of the description will be omitted. In addition, some components of the drawings may be exaggerated, omitted, or schematically illustrated. The size of each component does not entirely reflect the actual size, and therefore, the contents described herein are not limited by the relative sizes or spacings of the components drawn in each drawing.

In describing embodiments of the present invention, if it is judged that a detailed description of a known technology related to the present invention may unnecessarily obscure the gist of the present invention, the detailed description will be omitted. In addition, the terms described below are terms defined in consideration of their functions in the present invention, and may vary depending on the intention or custom of the user or operator. Therefore, the definitions should be made based on the contents throughout this specification. The terms used in the detailed description are only for describing embodiments of the present invention, and should never be limited. Unless clearly used otherwise, the singular form includes the plural form. In this description, expressions such as "comprises" or "comprising" are intended to indicate certain features, numbers, steps, operations, elements, parts or combinations thereof, and should not be construed to exclude the presence or possibility of one or more other features, numbers, steps, operations, elements, parts or combinations thereof other than those described.

Additionally, although the terms first, second, etc. may be used to describe various components, the components are not limited by the terms, and the terms are used only for the purpose of distinguishing one component from another.

FIG. 1 is an exemplary perspective view of a torque sensor module (100) according to one embodiment of the present invention. FIG. 2 is a front view of the torque sensor module (100) of FIG. 1.

Referring to FIGS. 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)} attached to each of a plurality of strain measuring holes (112) of the body (110), and a circuit board (130) connected to signal lines from each of the strain gauges of the strain gauge pairs {(SG1, SG2), (SG3, SG4), (SG5, SG6)} attached to each of the plurality of strain measuring holes (112). Here, it is preferable that the strain gauge pairs {(SG1, SG2), (SG3, SG4), (SG5, SG6)} be three pairs, but if necessary, additional strain measurement holes (112) may be provided and additional strain gauge pairs attached thereto may be provided.

The circuit board (130) is manufactured in the form of a ring-shaped PCB (Printed Circuit Board) board as illustrated in the drawing, and can be mounted on either side of the body (110). The circuit board (130) is manufactured and mounted on the body (110) so that the portion crossing the central hole (119) of the body (110) is open so that no part of the circuit board (130) is caught, and can be mounted on a predetermined axis provided on an arm of a robot, etc., that is, to detect and control any axis on a rectangular coordinate system, i.e., the z-axis torque (Tz), through the central hole (119) of the body (110). The circuit board (130) may be equipped with circuit components such as an amplifier, an AD (Analog to Digital) converter, and an operation unit for digitally processing detection signals from signal lines of each strain gauge {(SG1, SG2), (SG3, SG4), (SG5, SG6)} to calculate torque values, etc.

Here, an exemplary structure of a torque sensor module (100) according to one embodiment of the present invention is described, but it is to be noted in advance that this is only an exemplary description and that the structure of the body (110), the plurality of strain measuring holes (112) of the body (110) or other holes may have various shapes or forms.

As shown in FIGS. 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 rigidity adjustment hole (114) formed along a circumferential direction between a central hole (119) and an outer peripheral surface, wherein the first sensitivity adjustment hole (111), the strain measurement hole (112), the second sensitivity adjustment hole (113), and the rigidity adjustment hole (114) are sequentially formed twice or more repeatedly.

One or, preferably, a plurality of rigidity adjustment holes (114) are formed 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).

A first sensitivity adjustment hole (111) and a second sensitivity adjustment hole (113) are formed at positions spaced apart from the strain measurement hole (112) at both sides in the circumferential direction with respect to the strain measurement hole (112), and a plurality of stiffness adjustment holes (114) can be formed at positions spaced apart so as to have a predetermined pitch in the circumferential direction. A predetermined distance can also be formed between each of the holes at both ends of the stiffness adjustment hole (114) and the first sensitivity adjustment hole (111) or the second sensitivity adjustment hole (113).

Each strain measuring hole (112) is a hole for attaching a strain gauge pair {(SG1, SG2), (SG3, SG4), (SG5, SG6)} for measuring the strain applied to the torque sensor module (100) at the location where the torque sensor module (100) is installed, and as shown in the drawing, each strain gauge pair {(SG1, SG2), (SG3, SG4), (SG5, SG6)} is attached one by one to opposite sides of each strain measuring hole (112), i.e., opposite sides of the circumferential direction.

It is preferable that the first sensitivity adjustment hole (111) and the second sensitivity adjustment hole (113), which are symmetrically formed on each side of the strain measurement hole (112), are formed at a predetermined distance from the strain measurement hole (112) in the circumferential direction and formed to an appropriate size so that the strain gauges {(SG1, SG2), (SG3, SG4), (SG5, SG6)} can generate a detection signal measuring an appropriate strain (or deformation) at the corresponding position.

In addition, the strain measurement hole (112) is formed in a trapezoidal shape with a length greater on the central side than on the outer peripheral side, which is advantageous for measuring the strain of each strain gauge {(SG1, SG2), (SG3, SG4), (SG5, SG6)}. Since the sensitivity of each strain gauge {(SG1, SG2), (SG3, SG4), (SG5, SG6)} may vary depending on its arrangement position, the distance from the first sensitivity adjustment hole (111) and the second sensitivity adjustment hole (113), the hole size, etc., the distance from the first sensitivity adjustment hole (111) and the second sensitivity adjustment hole (113) and the hole size should be formed to an appropriate distance and size depending on the purpose, and it is also preferable that the inclinations of the circumferential walls on both sides of the trapezoidal shape to which the strain gauges {(SG1, SG2), (SG3, SG4), (SG5, SG6)} are attached be formed to have an appropriate symmetrical inclination.

In addition, the holes of the first sensitivity adjustment hole (111), the second sensitivity adjustment hole (113), and the stiffness adjustment hole (114) are exemplarily illustrated as being circular, but are not limited thereto, and may be formed in various shapes such as circular, oval, trapezoidal, triangular, square, and polygonal shapes such as pentagons.

A plurality of stiffness adjustment holes (114) can be formed at positions spaced apart from each other so as to have a predetermined pitch in the circumferential direction. The number of stiffness adjustment holes (114) can be formed between the second sensitivity adjustment hole (113) and the first sensitivity adjustment hole (111) with an appropriate size and a suitable spacing distance so that a predetermined stiffness can be maintained. The formation of the stiffness adjustment holes (114) of the present invention is not a shape formed by spoke-shaped spokes like in the related art (Patent Application No. 10-2009-0115343) (there are relatively many holes between the spokes), but holes formed on a surface of the body (110) itself that extends to the outer circumference (since the spokes are between the holes, the spoke area is larger than in the related art), so that the stiffness can be increased so as to maintain the shape of the torque sensor module (100) better than in the spoke shape.

Furthermore, as shown in FIGS. 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 positioned on the same first distance (r1) from the center (O) of the body (110). Accordingly, it is possible to provide strain sensor information for deformation in any direction in a balanced manner.

The strain measuring hole (112) having a trapezoidal shape may be formed so that its center is located on the same first distance (r1) from the center (O) as the first sensitivity adjustment hole (111), the second sensitivity adjustment hole (113), and the stiffness adjustment hole (114), i.e., on the same arc about the center (O). However, the present invention is not limited thereto, and the strain measuring hole (112) may be arranged so that at least a portion of the region (space inside the hole) excluding the four sides of the trapezoidal shape is intersected by an arc about the center (O) of the first distance (r1).

Additionally, the sensitivity of each strain gauge {(SG1, SG2), (SG3, SG4), (SG5, SG6)} may vary depending on where it is placed on the walls on both sides of the strain measurement hole (112). For example, in a case where a trapezoidal strain measuring hole (112) is formed so that its center is located on the same first distance (r1) from the center (O) as the first sensitivity adjustment hole (111), the second sensitivity adjustment hole (113), and the stiffness adjustment hole (114), i.e., on the same arc relative to the center (O), each of the strain gauges {(SG1, SG2), (SG3, SG4), (SG5, SG6)} may be arranged so that the center of its bottom surface (attachment surface) is located on the same first distance (r1) from the center (O), but preferably, the strain gauges {(SG1, SG2), (SG3, SG4), (SG5, SG6)} are arranged so that the center of its bottom surface (attachment surface) is located at a distance less 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, 113), which is advantageous for strain detection.

In FIGS. 1 and 2, the stiffness adjustment holes (114) can be formed in an appropriate number so as to appropriately reduce the overall weight while maintaining the rigidity of the torque sensor module (100), and in order to further reduce the weight, an appropriate number of holes (150) can be formed on an extra surface of the body (110) on a second distance (r2) from the center (O), and further, an appropriate number of holes (160) can be further formed on an extra surface of the body (110) on a third distance (r3) from the center (O). Such holes (111, 112, 113, 114, 150, 160) can also be used for installing cables or parts for connection with the circuit board (130) or for coupling with other parts constituting the robot.

In particular, in the torque sensor module (100) of the present invention, the calibration matrix (or gain) (A) for the strain gauges {(SG1, SG2), (SG3, SG4), (SG5, SG6)} of the torque sensor module (100) designed using three full-bridge configurations and three half-bridge configurations through a combination of six strain gauges {(SG1, SG2), (SG3, SG4), (SG5, SG6)} can be obtained in advance, and the calibration matrix (A) obtained in this way is applied to the torque sensor module (100) to precisely detect force and torque for one axis or further for multiple axes, and to enable precise control of robot joints such as a robot arm, neck, and wrist.

To this end, first, the strain gauge pairs {(SG1, SG2), (SG3, SG4), (SG5, SG6)} attached to each of the above multiple locations of the torque sensor module (100) are connected in series between the first power supply (VCC) and the second power supply (GND) as shown in FIG. 3.

FIG. 3 is a drawing for explaining the connection state of strain gauges {(SG1, SG2), (SG3, SG4), (SG5, SG6)} of the present invention.

Referring to FIG. 3, a first power source (VCC) and a second power source (GND) are supplied through a circuit board (130), and the series connection of each pair of strain gauges {(SG1, SG2), (SG3, SG4), (SG5, SG6)} may be such that the connection lines connected to the corresponding terminals of the strain gauges are extended to the circuit board (130) and then electrically connected to the circuit board (130) to form a contact point (or a center tab), or the connection lines connected to the corresponding terminals of the strain gauges may be electrically connected to the outside of the circuit board (130) to form a contact point and then extended to be connected to the circuit board (130) to provide the corresponding voltage.

When the torque sensor module (100) is mounted on a robot joint or the like and operates, each sensing voltage (V12, V34, V56) from each contact point in a serially connected state of the strain gauge pairs {(SG1, SG2), (SG3, SG4), (SG5, SG6)} attached to each of the plurality of positions is provided to the circuit board (130). The circuit board (130) can perform torque control of the robot based on each sensing voltage (V12, V34, V56) detected from the strain gauge pairs {(SG1, SG2), (SG3, SG4), (SG5, SG6)}.

However, before the torque sensor module (100) is mounted on a robot joint or the like and operates, a calibration gain (A) for the designed or manufactured torque sensor module (100) must be obtained in advance through an analysis device (not shown) and applied to the circuit of the circuit board (130) so that the torque received by the torque sensor module (100) is appropriately calculated based on the sensing voltage of the strain gauges.

Although the multiple locations where the strain gauges {(SG1, SG2), (SG3, SG4), (SG5, SG6)} are attached above are exemplarily described as being attached to the strain measurement holes (112), the structure of the torque sensor module (100) for obtaining such calibration gain (A) may have various forms, and accordingly, the multiple locations where the strain gauges {(SG1, SG2), (SG3, SG4), (SG5, SG6)} are attached may be appropriate locations according to various structures of the torque sensor module (100). For example, in the torque sensor module of another embodiment of the present invention, a pair of strain gauges may be attached to each of a plurality of spokes (see Patent Application No. 10-2009-0115343) formed in the circumferential direction of a wheel spoke-shaped body (110) so as to face each other in the circumferential direction. That is, it is not limited to the structure of the torque sensor module (100) as shown in FIGS. 1 and 2, but in order to appropriately calculate the torque received by the torque sensor module (100) based on the sensing voltages (V12, V34, V56) of the strain gauges in torque sensor modules of various structures, the 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 of the circuit board (130).

FIG. 4 is a flowchart for explaining a calibration method in a device for analyzing the operation of a torque sensor module (100) according to one embodiment of the present invention.

Referring to FIG. 4, a device (analysis device) for analyzing the operation of a torque sensor module (100) may include a step (S110) of receiving a sensing voltage (V12, V34, V56) of each contact point of a strain gauge pair {(SG1, SG2), (SG3, SG4), (SG5, SG6)} for an input torque (T) to the torque sensor module (100), a step (S120) of calculating a differential component (S), a step (S130) of calculating a calibration gain (A), and a step (S140) of applying the same to a circuit of a circuit board (130).

The step (S110) of receiving the sensing voltage (V12, V34, V56) of each of the above contact points may include a step of receiving the sensing voltage (V12, V34, V56) from each contact point in a state where a pair of strain gauges {(SG1, SG2), (SG3, SG4), (SG5, SG6)} mounted at each of a plurality of locations on the torque sensor module (100) are connected in series after the input torque (T) is applied to the torque sensor module (100).

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

The input torque (T) can be expressed as a matrix as in the following [Mathematical Formula 1]. The input torque (T) can be prepared and applied in advance as predetermined values to perform regression analysis or learning by a neural network as described below. The input torque (T) can include values for one or more of the forces or torques for the three axes of the rectangular coordinate system and the torques for the three axes (see FIG. 5).

[Mathematical Formula 1]

T = [w1, w2, w3, w4, w5, T _Z ] ^T

Here, the torque value (Tz) for one axis (e.g., z-axis) among the three axes of the rectangular coordinate system can be the target torque value, and at this time, w1, w2, w3, w4, and w5 are unwanted forces or torque components, and may be crosstalk (mutual interference or capture) that affects the torque value output of the torque sensor module, such as torque components of other axes (e.g., x, y-axes), force components for each axis (e.g., x, y, z-axes), etc. However, the present invention is not limited thereto, and that is, w1, w2, w3, w4, and w5 may be, respectively, an x-axis force component fx, a y-axis force component fy, a z-axis force component fz, an x-axis torque component Tx, and a y-axis torque component Ty. For example, the calibration of the present invention may be performed to obtain Tz by using w1 to w5 as crosstalk and the z-axis torque component Tz as a target torque, and further, in addition to the z-axis torque component Tz, calibration may be performed by additionally setting one or more of w1 to w5, that is, a force component or a torque component, as a meaningful target value (see FIG. 5).

Next, the step (S120) of calculating the differential component (S) may include a step of calculating the differential component (S) including a first differential value (VR12, VR34, VR56) between the reference voltage (Vref) and each of the sensing voltages (V12, V34, V56), and a second differential value (V1234, V3456, V1256) for each of two combinations of the sensing voltages (V12, V34, V56).

The difference component (S) can be expressed as a matrix as in [Mathematical Formula 2] and [Mathematical Formula 3] below. The difference component (S) can be calculated based on each sensing voltage (V12, V34, V56) each time the input torque (T) is input to perform regression analysis or learning by a neural network as described below.

[Mathematical formula 2]

S = [V1234, V3456, V1256, VR12, VR34, VR56] ^T

[Mathematical Formula 3]

V1234 = V12 - V34

V3456 = V34 - V56

V1256 = V12 - V56

VR12 = Vref - V12

VR34 = Vref - V34

VR56 = Vref - V56

Here, since each sensing voltage (V12, V34, V56) constitutes a half of the Wheatstone bridge, the first difference value (VR12, VR34, VR56) between the reference voltage (Vref) and each of the sensing voltages (V12, V34, V56) uses three half bridges (using strain gauges arranged at two of the four resistors of the bridge), and the second difference value (V1234, V3456, V1256) for each of the two combinations of the sensing voltages (V12, V34, V56) uses a full bridge of the Wheatstone bridge (using strain gauges arranged at all four resistor positions of the bridge). Since the method of calculating the torque value from the sensing voltage for the strain of each strain gauge in a Wheatstone bridge circuit including elements of strain gauges is well known, a detailed description thereof is omitted here (see Application No. 10-2023-0027956 (2023.03.02)).

Next, the step (S130) of calculating the calibration gain (A) may include a step of calculating the calibration gain (A) corresponding to the input torque (T) and the differential component (S). The calibration gain (A) may be calculated to satisfy [Mathematical Formula 4].

[Mathematical Formula 4]

(T - AS) = k

Here, k can correspond to the error to be minimized, can be set to 0, or can be another real number specified in advance for calibration.

That is, learning is performed by changing the values of the input torque (T), and the calibration gain (A) is determined as in [Mathematical Formula 5] based on 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 on it. For example, in the example above, the input torque (T), the differential component (S), and the minimum value (k) may be an m=6th order column vector, and the calibration gain (A) (or matrix) may be a 6Х6 dimensional matrix having A11 to A66 as elements, as in [Mathematical Formula 5].

[Mathematical Formula 5]

Next, the step (S140) of applying the calibration gain (A) to the circuit of the circuit board (130) may include a step of applying the calibration gain (A) to the circuit of the circuit board (130) so as to calculate the torque received by the torque sensor module (100) in the circuit of the circuit board (130) of the torque sensor module (100) according to the calibration gain (A). That is, the calibration gain (A) may be stored in a memory such as a ROM or RAM of the circuit board (130) and utilized to calculate the torque from the sensing voltages (V12, V34, V56) such as 'T = AS'.

The device (analysis device) for analyzing the operation of the torque sensor module (100) of the present invention described above may be composed of hardware, software, or a combination thereof. For example, it may be implemented as a server or computing system having at least one processor for performing the functions described above.

Such a computing system may include at least one processor, memory, a user interface input device, a user interface output device, storage, and a network interface connected via a bus. The processor may be a central processing unit (CPU) or a semiconductor device that executes processing on instructions stored in the memory and/or storage. The memory and storage may include various types of volatile or nonvolatile storage media. For example, the memory may include a read only memory (ROM) and a random access memory (RAM).

Accordingly, the steps of a method or algorithm described in connection with the embodiments disclosed herein may be implemented directly in hardware, a software module, or a combination of the two executed by such a processor. The software module 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, a hard disk, a removable disk, a CD-ROM. An exemplary storage medium is coupled to the processor such that the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. The processor and the storage medium may reside in an application specific integrated circuit (ASIC). The ASIC may reside in a user terminal. In the alternative, the processor and the storage medium may reside as discrete components in a user terminal.

Figure 6 is a block diagram of the configuration of the circuit board (130) of the torque sensor module (100) of the present invention.

Referring to FIG. 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) (e.g., VCC/2 possible when RA=RB) at the contact points of resistors (RA, RB) connected in series between a first power source (VCC) and a second power source (GND), a memory (620) such as a ROM or RAM that stores a calibration gain (A), a torque detection unit (630) that calculates a torque ('AS+k' or 'AS' in the above equations) corresponding to the sensing voltages (V12, V34, V56) from a strain gauge and the reference voltage (Vref) and the calibration gain (A), and a torque control unit (640) that generates a command for torque control based on the torque calculated by the torque detection unit (630).

For example, the torque detection unit (630) receives sensing voltages from a plurality of strain gauges mounted on the torque sensor module (100), and receives each sensing voltage (V12, V34, V56) from each contact point in a state where a pair of strain gauges {(SG1, SG2), (SG3, SG4), (SG5, SG6)} attached to each of a plurality of positions are connected in series, and calculates a differential component (S) including a first differential value between a reference voltage (Vref) from a reference voltage generator (610) and each sensing voltage (V12, V34, V56), and a second differential value for each of two combinations of the sensing voltages (V12, V34, V56) (see Equations 2 and 3), so as to calculate a torque (AS+k' or 'AS') corresponding to the differential component (S) and a calibration gain (A) (see Equation 5) (see Equation 4). The torque detection unit (630) may be equipped with an amplifier for receiving each sensing voltage (V12, V34, V56) and an ADC (Analog-to-Digital Converter) for converting the analog signal output of the amplifier into a digital signal.

That is, as described in the description of FIG. 4, the calibration gain (A) is calculated in advance for each sensing voltage (V12, V34, V56) in the torque sensor module (100) for a given input torque (T) to correspond to the input torque (T) and the differential component (S), and is stored in the memory (620) and used.

Here, the torque ('AS+k' or 'AS') calculated by the torque detection unit (630) may be a target torque value as a torque value (Tz) for one of the three axes (e.g., z-axis) of the rectangular coordinate system, and among the components calculated here, w1, w2, w3, w4, and w5 described above are unwanted force or torque components, which may be crosstalk (mutual interference or capture) that affects the torque value output of the torque sensor module, and may be torque components for other axes (e.g., x, y-axis) or force components for each axis (e.g., x, y, z-axis), so that these components may be ignored. However, the present invention is not limited thereto, and that is, among the components calculated here, w1, w2, w3, w4, and w5 may be, respectively, an x-axis force component fx, a y-axis force component fy, a z-axis force component fz, an x-axis torque component Tx, and a y-axis torque component Ty. For example, Tz can be obtained by using 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 the components w1 to w5, that is, the force component or the torque component, can be additionally set as a meaningful target value to calculate the corresponding torque value.

The torque control unit (640) generates a command for torque control of robot joints, etc. based on the torque calculated by the torque detection unit (630), thereby enabling precise control of the movement of robot joints, etc.

As described above, in the torque sensor module (100) according to the present invention, the calibration matrix (or gain) (A) for the strain gauges {(SG1, SG2), (SG3, SG4), (SG5, SG6)} of the torque sensor module (100) designed using three full-bridge configurations and three half-bridge configurations through a combination of six strain gauges {(SG1, SG2), (SG3, SG4), (SG5, SG6)} can be obtained in advance, and the calibration matrix (A) obtained in this way is applied to the torque sensor module (100) to precisely detect force and torque for one axis or further for multiple axes, and to enable precise control of robot joints such as a robot arm, neck, and wrist.

Accordingly, by precisely applying the sensor information of strain gauges {(SG1, SG2), (SG3, SG4), (SG5, SG6)}, a high-performance torque sensor module (100) can be implemented, and for example, despite the influence of crosstalk such as force (z-axis bending force) caused by a person pushing or colliding with it, it can assist in precisely controlling the rotational force on the xy plane, i.e., the z-axis torque (Tz). In some cases, it can be applied to the torque sensor module (100) of a robot joint in which force or torque of multiple axes (e.g., 6 axes) such as the neck and wrist are controlled, and assist in precisely controlling the force or torque.

Although the present invention has been described with reference to specific details such as specific components and limited examples and drawings, these have been provided only to help a more general understanding of the present invention, and the present invention is not limited to the above-described examples, and those with ordinary skill in the art to which the present invention pertains may make various modifications and variations without departing from the essential characteristics of the present invention. Therefore, the spirit of the present invention should not be limited to the described examples, and all technical ideas that are equivalent or equivalent to the scope of the following claims, as well as the claims, should be interpreted as being included in the scope of the rights of the present invention.

Claims (6)

In a calibration method in a device for analyzing the operation of a torque sensor module, For input torque, a step of receiving sensing voltages from a plurality of strain gauges mounted on the torque sensor module, wherein each sensing voltage is received from each contact point in a state where a pair of strain gauges attached to each of a plurality of positions are connected in series; A step of calculating a differential component including a first differential value between a reference voltage and each of the sensing voltages, and a second differential value for each of two combinations of the sensing voltages; A step of calculating a calibration gain corresponding to the input torque and the differential component; and A step of applying the calibration gain to the circuit of the torque sensor module so as to calculate the torque received by the torque sensor module according to the calibration gain. A calibration method comprising: In the first paragraph, The above input torque is a calibration method including values for one or more of the forces or torques about the three axes of the rectangular coordinate system and the torques about the three axes. In the first paragraph, In the step of calculating the above calibration gain, A calibration method for calculating the calibration gain so as to satisfy the mathematical formula '(T - AS) = k', wherein T is the input torque, A is the calibration gain, S is the differential component, and k is 0 or a real number value determined in advance for calibration. In the first paragraph, A calibration method for determining the calibration gain based on the results of regression analysis or neural network learning so that the calibration gain has a predetermined minimum value while changing the values of the input torque. Reference voltage generator; Memory that stores the calibration gains; A torque detection unit which receives sensing voltages from a plurality of strain gauges mounted on a torque sensor module, receives each sensing voltage from each contact point in a state where a pair of strain gauges attached to each of a plurality of locations are connected in series, calculates a differential component including a first differential value between a reference voltage from the reference voltage generator and each of the sensing voltages, and a second differential value for each of two combinations of the sensing voltages, and calculates a torque corresponding to the differential component and the calibration gain; and A torque control unit is included that generates a command for torque control based on the torque produced above, The torque sensor module circuit of the present invention is a torque sensor module circuit in which the calibration gain is calculated in advance to correspond to the input torque and the differential component for each sensing voltage in the torque sensor module for a given input torque and stored in the memory. In paragraph 5, The above torque sensor module, 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 a circumferential direction between a central hole and an outer surface; and A torque sensor module circuit in which the strain measuring hole having the pair of strain gauges attached has a trapezoidal shape with a length of a central side longer than an outer peripheral side.

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