JP2010014695A - Multiaxial sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multiaxial sensor that relaxes the compound force error, comparing with the conventional technology and accurately detects six-axis force and moment. <P>SOLUTION: This multiaxial sensor comprises a first member 100, having six flexible portions 111-116 having a plurality of distortion detecting elements R11-R64; a second member having a second flexible portions facing respective first flexible portions 111-116; coupling objects 121-126 for connecting respective first flexible portions 111-116 to the second flexible portions; and a force moment arithmetic means for calculating the six-axis force and moment, based on the output result of the plurality of distortion detecting elements R11-R64. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a multi-axis sensor, and more particularly to a technique for reducing the influence of a compound force error.

This type of prior art includes a first flange having four first flexible portions each having four strain gauges for detecting six-axis forces and moments, and these first flexible members. Strain gauge type comprising a second flange having four second flexible parts arranged at positions facing the parts, and a connecting body for connecting each first flexible part and each second flexible part A sensor is disclosed (for example, see Patent Document 1). In such a conventional strain gauge type sensor, as shown in FIG. 10 of Patent Document 1, two bridge circuits are formed in each of the four first flexible portions. 8 voltage values corresponding to the distortion generated according to the six-axis forces and moments applied from the output are output.
JP 2008-96230 A

  By the way, the above-described conventional strain gauge type sensor has a problem that the combined force error becomes large. For example, the above-described conventional strain gauge type sensor requires an intermediate process for converting the outputs of eight bridge circuits into six intermediate variables when detecting six-axis forces and moments. However, an error component is generated in the course of such an intermediate process, and there is a problem that the six-axis force and moment cannot be accurately detected due to the accumulation of the generated error component.

  An object of the present invention is to provide a multi-axis sensor capable of reducing a complex force error as compared with the prior art and capable of accurately detecting six-axis forces and moments.

  In the multi-axis sensor according to the first invention, a first member having six first flexible parts in which a plurality of strain detection elements are arranged, and a second flexible part facing each of the first flexible parts. A force member for calculating six-axis forces and moments based on output results of a plurality of strain sensing elements, a second member having a connecting member, a connecting body for connecting the first flexible portion and the second flexible portion, respectively. And an arithmetic means.

  In this multi-axis sensor, since the number of the first flexible portions provided on the first member is six, four first flexible portions are provided on the first member in the calculation process of the six-axis force and moment. There is no need to perform intermediate processing as in Patent Document 1 provided. Therefore, the generation of error components due to the intermediate processing can be suppressed, and the error components can be reduced as compared with Patent Document 1. Therefore, the detection accuracy of the six-axis force and moment can be improved as compared with Patent Document 1.

  In the multi-axis sensor according to the second invention, a first member having a plurality of first flexible portions in which a plurality of strain detection elements are arranged, and a second flexible portion facing each of the first flexible portions. A second member having a connecting body, a connecting body for connecting the first flexible portion and the second flexible portion, and a force moment calculating means for calculating six-axis forces and moments based on the output results of the plurality of strain detecting elements. The first flexible part, the second flexible part, and the coupling body are formed at equal angles around the central axis and at equal distances from the central axis in the first member and the second member. The force-moment calculation means is arranged in six or more even-numbered groups, and the force-moment calculating means is configured to output the six-axis force and the six-axis force based on the output results of the plurality of strain detection elements from the group selected by skipping one of the even-numbered groups. A first force moment calculating means for calculating a moment, and a plurality of the remaining sets of the even number set Second force moment calculating means for calculating six-axis force and moment based on the output result of the strain detection element, six-axis force and moment calculated by the first force-moment calculating means, and second force-moment calculating means Output calculating means for calculating the six-axis force and moment based on the six-axis force and moment calculated by.

  In this multi-axis sensor, due to the existence of symmetry between each strain detection element belonging to the group selected by skipping one of the even pairs and each strain detection element belonging to the remaining group among the even pairs, the above-mentioned composite Force error can be reduced.

  In the multi-axis sensor according to the third aspect of the invention, in the multi-axis sensor according to the second aspect of the invention, the output calculation means includes the six-axis force and moment calculated by the first force-moment calculation means and the second force-moment calculation. The average value of the six-axis forces and moments calculated by the means is calculated as the six-axis forces and moments.

  In this multi-axis sensor, due to the existence of symmetry between each strain detection element belonging to the group selected by skipping one of the even pairs and each strain detection element belonging to the remaining group among the even pairs, the above-mentioned composite Power error can be strongly offset.

  In the multi-axis sensor according to the fourth invention, in the multi-axis sensor according to the second or third invention, the six-axis force and moment calculated by the first force-moment calculating means and the second force-moment calculating means are used. When comparing the calculated force and moment of the six axes and determining whether the comparison result is greater than or equal to a predetermined amount, and when the comparison result determines that the comparison result is greater than or equal to a predetermined amount And an abnormal process executing means for executing a predetermined abnormal process.

  In this multi-axis sensor, since the failure of the strain detection element can be detected, the reliability of the multi-axis sensor can be improved.

  In the multi-axis sensor according to the fifth aspect, in the multi-axis sensor according to any one of the second to fourth aspects, the even-numbered set is six sets.

  With this multi-axis sensor, the configuration can be simplified and the manufacturing cost can be reduced.

  In the multi-axis sensor according to the sixth aspect, in the multi-axis sensor according to any one of the second to fourth aspects, the even-numbered set is eight sets.

  This multi-axis sensor has point symmetry of 22.5 °, 67.5 °, 112.5 °, and 157.5 ° around the Z-axis, and is line-symmetric with respect to the X-axis and Y-axis. Exhibits sex. Therefore, it is possible to further reduce one aspect of the combined force error in which the output changes corresponding to the Z-axis rotation phase.

  As described above, according to the present invention, the following effects can be obtained.

  In the first invention, since the number of the first flexible portions provided on the first member is six, four first flexible portions are provided on the first member in the process of calculating the six-axis force and moment. There is no need to perform intermediate processing as in Patent Document 1 provided. Therefore, the generation of error components due to the intermediate processing can be suppressed, and the error components can be reduced as compared with Patent Document 1. Therefore, the detection accuracy of the six-axis force and moment can be improved as compared with Patent Document 1.

  Further, in the second invention, due to the existence of symmetry between each strain detecting element belonging to the group selected by skipping one of the even sets and each strain detecting element belonging to the remaining group among the even sets, The combined force error can be alleviated.

  Further, in the third invention, due to the existence of symmetry between each strain detecting element belonging to the group selected by skipping one of the even sets and each strain detecting element belonging to the remaining set among the even sets, The combined force error can be strongly canceled.

  In the fourth invention, since the failure of the strain detection element can be detected, the reliability of the multi-axis sensor can be improved.

  In the fifth invention, the configuration of the multi-axis sensor can be simplified, and the manufacturing cost can be suppressed.

  In the sixth aspect of the invention, the point symmetry of 22.5 °, 67.5 °, 112.5 °, and 157.5 ° with respect to the Z axis and the line symmetry with respect to the X axis and the Y axis are further improved. Exhibiting symmetry. Therefore, it is possible to further reduce one aspect of the combined force error in which the output changes corresponding to the Z-axis rotation phase.

(First embodiment)
The 6-axis sensor 1 (multi-axis sensor) according to the first embodiment of the present invention will be described below based on the drawings. FIG. 1 is a plan view illustrating the arrangement of the flexible portions 111 to 116 (first flexible portion) when the flange 100 (first member) is seen through from the flange 200 (second member) side in the Z-axis direction. It is. 2 is a cross-sectional view taken along line AA shown in FIG. FIG. 3 is a cross-sectional view taken along line BB shown in FIG. Each code | symbol C1-C6 of FIG. 1 has shown the center of each flexible part 111-116. In this embodiment, for convenience of explanation, an XYZ three-dimensional coordinate system is defined, and the arrangement of each component is described with reference to this coordinate system. Therefore, in FIG. 2, the center position of the front side surface 100a of the flange 100 is defined as the origin O, the right horizontal direction is defined as the X axis, the front side perpendicular to the paper surface is defined as the Y axis, and the upper vertical direction is defined as the Z axis. That is, the front side surface 100 a of the flange 100 defines the XY plane, and the Z axis passes through the center position of the flange 100.

  In FIG. 1, a 6-axis sensor 1 is a sensor that measures at least one of multiaxial forces, moments, accelerations, and angular accelerations applied to disk-shaped flanges 100, 200 formed of metal or the like. In addition to 100 and 200, it has a fixing part 300. The 6-axis sensor 1 includes a plurality of strain gauges R11 to R64 (force detection elements) attached to the back side surface 100b of the flange 100.

  As shown in FIG. 2, the flange 100 is fixed on the fixing portion 300. The flange 100 has flexible portions 111 to 116. These flexible portions 111 to 116 are formed thin. Connected bodies 121 to 126 are provided at substantially central portions of the flexible portions 111 to 116, respectively. The flange 200 has flexible portions 211 to 216 (second flexible portions) at positions facing the flexible portions 111 to 116 of the flange 100. These flexible portions 211 to 216 are formed thin like the flexible portions 111 to 116, and connecting bodies 221 to 226 are provided at substantially central portions thereof. The flexible portions 111 to 116 and 211 to 216 have an annular shape by including the coupling bodies 121 to 126 and 221 to 226, respectively, in a substantially central portion.

  In FIG. 2, for convenience of explanation, only the flexible portions 211, 212, and 216 and the coupling bodies 221, 222, and 226 are illustrated, and the other flexible portions 213, 214, 215 and the coupling bodies 223, 224, and 225 are illustrated. Illustration is omitted. Similarly, for convenience of explanation, FIG. 3 also shows only the flexible portions 211 and 214 and the coupling bodies 221 and 224, and the other flexible portions 212, 213, 215 and 216 and the coupling bodies 222, 223 and 225, Illustration of 226 is omitted.

  The connecting bodies 121 to 126 of the flexible portions 111 to 116 and the connecting bodies 221 to 226 of the flexible portions 211 to 216 are firmly connected using an appropriate means such as a bolt member (not shown), and the flange 100 and the flange Each flexible part and each coupling body provided in 200 are substantially symmetrical. Further, the coupling bodies 121 to 126 and the coupling bodies 221 to 226 have strong rigidity as compared with the flexible parts 111 to 116 and the flexible parts 211 to 216 by such a strong coupling, and can be regarded as an integral body. . In this example, the connecting bodies 121 to 126 and the connecting bodies 221 to 226 are formed separately, but the pair of connecting bodies 121 and 221, the connecting bodies 122 and 222, the connecting bodies 123 and 223, the connecting body 124, 224, the coupling bodies 125 and 225, and the coupling bodies 126 and 226 may be integrally formed, and the coupling bodies integrally formed in this way may be combined as a part of the flange 100 or the flange 200.

  As shown in FIG. 1, the flexible portions 111 to 116 are formed at equal intervals around the Z axis along the circumferential direction of the flange 100. In this example, each flexible part 111-116 is arrange | positioned every 60 degree | times. These flexible portions 111 to 116 are arranged in the positive and negative directions of the X axis and the Y axis, respectively. Further, the flexible portions 211 to 216 of the flange 200 are disposed at positions facing the flexible portions 111 to 116. Therefore, the 6-axis sensor 1 functions as a 6-axis force sensor for measuring three-axis forces of the X axis, the Y axis, and the Z axis that are orthogonal to each other in a three-dimensional space and moments around those axes.

  The fixed portion 300 has a structure in which the center of the surface facing the flange 100 is concave, and the flange 100 is coupled to and supported by the flange 100 at the peripheral portion. In addition, this fixing | fixed part 300 also has the objective of protecting the strain gauges R11-R64. As described above, since the thin flexible portions 111 to 116 are formed on the flange 100 and the thin flexible portions 211 to 216 are formed on the flange 200, the flange 100 is placed on the fixed portion 300. When any force is applied to the flange 200 in a fixed state, the force is transmitted to the flexible parts 111 to 116 through the connecting bodies 121 to 126 and the connecting bodies 221 to 226, and the flexible parts 111 to 116 are applied to the flexible parts 111 to 116 according to the magnitude and direction of the force. It has a structure in which distortion occurs. That is, the flange 100, the flange 200, the coupling bodies 121 to 126, and the coupling bodies 221 to 226 constitute a so-called strain body.

  As shown in FIG. 1, each flexible part 111-116 has four strain gauges R11-R64, respectively. As shown in FIG. 2, these strain gauges R <b> 11 to R <b> 64 are disposed on the outer edge portion and inner edge portion of each flexible portion 111 to 116 on the back side surface 100 b of the flange 100. When a force is applied to the flange 200, each of the flexible portions 111 to 116 generates the largest distortion near the boundary between the outer edge portion and the inner edge portion. Therefore, each of the strain gauges R11 to R64 is the portion where the distortion is most likely to occur, and is disposed on the lines L11 to L16 passing through the centers of the flexible portions 111 to 116 and perpendicular to the Z axis. Yes. The strain gauges R11 to R64 are set so that the sensitivity is highest in the directions of the lines L11 to L16. 1 to 3, illustration of the lead wires of the strain gauges is omitted.

  The strain gauges R <b> 11 to R <b> 64 are a kind of resistor, and are detection elements that are used by being attached to a place where distortion occurs. Such a strain gauge can measure strain ε by detecting a change in resistance value due to the occurrence of strain. A strain gauge in which a metal foil pattern is formed on a resin base material can be applied. Alternatively, an insulating film such as silicon oxide may be formed on the flange 100, and a strain gauge may be formed on the formed insulating film using a metal thin film such as an alloy of Cr or Ni or Cr oxide. In such a case, if the surface on which the strain gauge is formed is one flat surface, the strain gauge can be formed in a process using a sputtering apparatus or the like using a photolithography technique, which is suitable for mass production.

(Regarding the strain detection operation of each flexible part)
4-7 is explanatory drawing which shows the detection operation | movement of distortion at the time of applying force and a moment to the flange 200, FIGS. 4-6 is arrow sectional drawing of the CC line | wire shown in FIG. 7 shows a cross-sectional view taken along line BB shown in FIG. It should be noted that, in particular, among the components of the force and moment applied to the flange 200, the order of the force Fx in the X axis direction, the force Fz in the Z axis direction, the moment Mz around the Z axis, and the moment Mx around the X axis Now, description will be made with reference to FIGS.

(Force X in the X-axis direction)
FIG. 4 shows a state in which the flexible portion 111 of the flange 100 and the flexible portion 211 of the flange 200 are elastically deformed when a force Fx in the X-axis direction is applied to the flange 200. Since the direction of the force Fx applied at this time coincides with the direction in which the strain gauges R11 to R14 are arranged on the flexible portion 111 (see FIG. 2), each strain gauge R11 to R14 detects a large strain. Although not shown in FIG. 4, the arrangement direction of the strain gauges R <b> 41 to R <b> 44 also coincides with the direction of the force Fx in the flexible portion 114 as with the flexible portion 111 (see FIG. 1). The strain gauges R41 to R44 detect a large strain. On the other hand, with respect to the other flexible portions 112, 113, 115, and 116 (see FIG. 1) excluding the flexible portions 111 and 114, an array of strain gauges R21 to R24, R31 to R34, R51 to R54, and R61 to R64. Since the direction does not coincide with the direction of the force Fx, large strains such as the strain gauges R11 to R14 and R41 to R44 are not detected.

(Force Fz in the Z-axis direction)
FIG. 5 shows a state where the flexible portion 111 and the flexible portion 211 are elastically deformed when a force Fz in the Z-axis direction is applied to the flange 200. In this state, since the flexible portions 111 to 116 (see FIG. 1) are elastically deformed as shown in the figure, the strain gauges R11 to R64 of the flexible portions 111 to 116 detect the strain and change in the same pattern.

(Moment Mz around the Z axis)
FIG. 6 shows a state where the flexible portion 111 and the flexible portion 211 are elastically deformed when a moment Mz that rotates clockwise around the Z axis is applied to the flange 200. In this state, the coupling bodies 121 to 126 and the coupling bodies 221 to 226 are displaced so as to be tilted in the same rotation direction along the circumference around the Z axis. In response to this displacement, the flexible portions 111 to 116 are also displaced, and distortion occurs.

(Moment Mx around X axis)
FIG. 7 shows a state in which the flexible portions 111 and 114 and the flexible portions 211 and 214 are elastically deformed when a moment Mx about the X axis is applied to the flange 200. In this state, the flexible portions 111, 112, and 116 are pushed out to the fixed portion 300 side, and the flexible portions 113, 114, and 115 are displaced so as to be separated from the fixed portion 300 side (see FIG. 1). . Each strain gauge R11 to R64 changes in accordance with this displacement. Hereinafter, the force Fy in the Y-axis direction and the moment My around the Y-axis among the components of the force and the moment applied to the flange 200 will be described.

(Force Fy in the Y-axis direction)
When a force Fy in the Y-axis direction is applied to the flange 200, the direction of the force Fx is orthogonal to the arrangement direction of the strain gauges R11 to R14 and R41 to R44 of the flexible portions 111 and 114 (see FIG. 1). These strain gauges R11 to R14 and R41 to R44 hardly detect strain. In contrast, the strain gauges R21 to R24, R31 to R34, R51 to R54, and R61 to R64 of the flexible portions 112, 113, 115, and 116 (see FIG. 1) have the direction of the force Fy and the strain gauge arrangement. A certain amount of distortion is detected according to the angle.

(Moment My around Y axis)
When a moment My around the Y axis is applied to the flange 200, the flexible portions 112 and 113 are pushed out to the fixed portion 300 side, and the flexible portions 115 and 116 are displaced so as to be separated in the opposite direction to the fixed portion 300 side. (See FIG. 1). In accordance with this displacement, strain gauges R21 to R24, R31 to R34, R51 to R54, and R61 to R64 change, respectively. On the other hand, since the flexible portions 111 and 114 are on the Y axis, the strain gauges R11 to R14 and R41 to R44 do not change much.

  When the above detection operation is applied to the strain gauges R11 to R64 in FIG. 1, changes in resistance values of the strain gauges R11 to R64 are as shown in Table 1 below. However, only the increase / decrease (+/−) of the resistance value is considered, and the magnitude of the change is not considered. “+” Indicates that the tensile value is detected and the resistance value is increased, “−” indicates that the compressive strain is detected and the resistance value is decreased, and “0” indicates that almost no strain is generated and the resistance value is hardly changed. In the case of a force or moment in the opposite direction, the sign +/- is switched.

  From Table 1 above, six-axis forces and moments Fx, Fy, Fz, Mx, My, and Mz can be obtained using resistors R11 to R64 that can be regarded as 24 independent variables.

  FIG. 8 is an explanatory diagram showing a circuit diagram of six bridge circuits configured in each of the flexible portions 111 to 116 and their positional relationship. As shown in FIG. 8, the strain gauges R11 to R14, R21 to R24, R31 to R34, R41 to R44, R51 to R54, and R61 to R64 are configured to form a bridge circuit for each of the flexible portions 111 to 116. Wired. The bridge circuits of these strain gauges are spatially arranged symmetrically with respect to the Z axis, and are arranged symmetrically with respect to the X axis and the Y axis.

  When a constant voltage or current is applied to the bridge circuit configured as described above, the flexible portions 111 to 111 are changed according to the magnitudes of the six-axis forces Fx, Fy, Fz, Mx, My, and Mz acting on the flange 200. 116 is distorted. In accordance with the occurrence of this strain, the resistance value of each strain gauge changes as shown in Table 1, and the output voltages V11 to V62 at each node change. By utilizing this property, the six-axis forces and moments Fx, Fy, Fz, Mx, My, and Mz can be obtained by measuring the output voltages V11 to V62. This is the basic principle of distortion detection in this embodiment. FIG. 9 shows a vector diagram of the output voltages V11 to V62.

(About 6-axis force and moment calculation method)
Hereinafter, the contents of the calculation for calculating the six-axis forces and moments Fx, Fy, Fz, Mx, My, and Mz based on the output voltages V11 to V62 of the bridge circuit will be described in detail.

  First, for each of the measured output voltages V11 to V62, voltage differences (V11−V12), (V22−V21),..., (V62−V61) are obtained for each of the flexible portions 111 to 116, and each obtained voltage is obtained. As shown in the following formula (1), an amplification operation is performed on the difference by an appropriate method, and outputs V1 to V6 are calculated.

  It should be noted that the method of obtaining the voltage difference between the outputs V1, V3, V5 and the outputs V2, V4, V6 in the formula (1) is opposite in the direction of the change due to the force Fx and the change due to the moment Mz. This is to identify them so as not to match.

  Next, one force or moment of Fx, Fy, Fz, Mx, My, and Mz is sequentially applied to the apparatus using a special jig, and six-axis forces and moments Fx, Fy, Fz, Mx, and My are sequentially added. , Mz and the characteristic matrix [A], which is a coefficient representing the relationship between the six outputs V1 to V6, are calculated. Such an operation is performed according to the following equation (2).

  [A] in equation (2) indicates a 6 × 6 characteristic matrix.

Furthermore, when the inverse matrix [A] ⁻¹ of [A] is multiplied from the left side of both sides of this equation (2), as shown in the following equation (3), the six-axis forces and moments Fx, Fy, Fz, Mx , My, Mz can be obtained.

(Each error component generated in the 6-axis force and moment)
Next, for each error component generated in the six-axis force and moment, the conventional example disclosed in Patent Document 1 is compared with the present invention. Here, the errors received by the outputs V1 to V6 due to noise or the like are δ1 to δ6, and the errors occurring in the six-axis forces and moments Fx, Fy, Fz, Mx, My, Mz are respectively δFx, δFy, δFz. , ΔMx, δMy, and δMz, the following equation (4) is established.

  Therefore, each error δFx, δFy, δFz, δMx, δMy, δMz can be obtained as shown in the following equation (5).

  In contrast, the conventional example discloses an example in which there are four portions corresponding to the flexible portion of the present invention. In this conventional example, the method for obtaining the six-axis force and moment is different from the present invention, and an intermediate process is performed in which the output of eight bridge circuits arranged in each flexible part is made into six intermediate variables. The component is divided into components in the X-axis, Y-axis, and Z-axis directions, and six-axis forces and moments Fx, Fy, Fz, Mx, My, and Mz are obtained by calculating the sum and difference.

  In the conventional example, the 6-axis forces and moments Fx to Mz are signals corresponding to the outputs V1 to V6 of the present invention. An operation corresponding to Equation (3) is required. Based on these assumptions, the effects of errors in the present invention and the conventional example will be compared below.

  Here, in order to simplify the explanation, only the calculation of the force Fz disclosed in the conventional example will be considered. The force Fz is obtained by calculation using output signals X2P, X2N, X4P, X4N, Y1P, Y1N, Y3P, and Y3N from each bridge circuit.

  Specifically, when the respective errors of these output signals X2P to Y3N are δX2P to δY3N, the force Fz can be expressed by the following equation (6).

  As shown on the right side of the equation (6), the difference between the third term (δY1P + δY1N + δY3P + δY3N) and the fourth term (δX2P + δX2N + δX4PP + δX4N) is accumulated as an error δFz.

  Similarly, for other forces and moments Fx, Fy, Mx, My, and Mz, errors δFx, δFy, δMx, δMy, and δMz are accumulated in accordance with the number of calculation variables.

  When these results are applied to the above-described equation (5) in order to compare the present invention with the conventional example, the result shown in the following equation (7) is obtained.

  Under the assumption that an equivalent error occurs in the bridge circuit output due to noise or the like, the six-axis forces and moments Fx, Fy, Fz, Mx, My, Comparing the error components generated in Mz, obviously, the conventional calculation result (formula (7)) with intermediate processing has a larger error component than the calculation result (formula (5)) of the present invention. .

  From the above considerations, in the calculation method of the present invention, it is not necessary to perform intermediate processing as in the conventional example on each bridge circuit output, and a 6-axis force and moment are utilized using a direct characteristic matrix (inverse matrix). Can be calculated. Therefore, it can be said that the calculation method of the present invention is superior to the conventional calculation method because errors caused by repeating intermediate processing are not accumulated unlike the calculation method disclosed in the conventional example.

(Second Embodiment)
Hereinafter, a calculation method of the six-axis forces and moments Fx, Fy, Fz, Mx, My, and Mz according to the second embodiment of the present invention will be described in detail. In this embodiment, the same elements as those described in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

(About 6-axis force and moment calculation method)
In this embodiment, two strain gauges R11, R12, R23, R24, R31, R32, R43, R44, R51 among the four strain gauges respectively provided in the flexible portions 111 to 116 shown in FIG. , R52, R63, and R64 are used to construct a half-bridge circuit, and only the output voltages V11, V22, V31, V42, V51, and V62 of this half-bridge circuit are used to calculate six-axis forces and moments. Thus, this is different from the calculation method of the six-axis force and moment according to the first embodiment described above. FIG. 10 shows a vector diagram of the output voltages V11, V22, V31, V42, V51, and V62.

  In this embodiment, as shown in the following formula (8), amplification operations are performed on the measured output voltages V11, V22, V31, V42, V51, and V62 by an appropriate method to calculate outputs V1 to V6. To do. If the outputs V1 to V6 calculated in this way are used, the six-axis forces and moments Fx, Fy, Fz, Mx, and the like according to the above-described formulas (2) and (3), as in the first embodiment. My and Mz can be obtained.

  If the outputs V1 to V6 calculated in this way are used, the six-axis forces and moments Fx, Fy, Fz, Mx, and the like according to the above-described formulas (2) and (3), as in the first embodiment. My and Mz can be obtained. In the second embodiment, an example in which the six-axis force and moment are obtained using the output voltages V11, V22, V31, V42, V51, and V62 of the half-bridge circuit has been described. Similarly, even when V12, V21, V32, V41, V52, and V61 are used, the six-axis force and moment can be obtained.

  In the second embodiment, if both circuits of the output voltages V11, V22, V31, V42, V51, V62 and the output voltages V12, V21, V32, V41, V52, V61 are used in parallel, the signal Can be easily realized.

(Third embodiment)
Hereinafter, a calculation method of the six-axis forces and moments Fx, Fy, Fz, Mx, My, and Mz according to the third embodiment of the present invention will be described in detail. In this embodiment, the same elements as those described in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

(About 6-axis force and moment calculation method)
In this embodiment, the strain gauges R11 to R14, R31 to R34, and R51 to R54 are grouped as the first group, and the strain gauges R21 to R24, R41 to R44, and R61 to R64 are grouped as the second group. The six-axis force and moment Fx, Fy, Fz, Mx, My, and Mz are calculated based on the voltage, which is different from the above-described six-axis force and moment calculation method according to the first embodiment. . In this embodiment, two types of calculation are exemplified as the calculation method of the six-axis force and moment. The first calculation is simple and easy to handle, and the second calculation is excellent in detection accuracy although the calculation contents are complicated. First, the first calculation will be described, and then the second calculation will be described.

(First calculation)
First, using an appropriate jig, one of each of six-axis forces and moments Fx, Fy, Fz, Mx, My, and Mz is independently applied to the six-axis sensor 1, and the six-axis force is applied. And a characteristic matrix [A1] that is a coefficient representing the relationship between the moments Fx, Fy, Fz, Mx, My, Mz and the six output voltages V11, V12, V31, V32, V51, V52 of the first group. . Similarly, it is a coefficient representing the relationship between the six-axis forces and moments Fx, Fy, Fz, Mx, My, Mz and the six output voltages V21, V22, V41, V42, V61, V62 of the second group. A characteristic matrix [A2] is obtained. These are expressed by the following equations (9) and (10). However, [A1] and [A2] are 6 × 6 characteristic matrices.

  When the above equations (9) and (10) are multiplied by the inverse matrix of the above characteristic matrix from the left side, the following equations (11) and (12) are obtained.

  Here, the six-axis forces and moments Fx, Fy, Fz, Mx, My, Mz obtained by the above equation (11) and the six-axis forces and moments Fx, Fy, Fz, obtained by the above equation (12). Since Mx, My, and Mz have different calculation processes, they are distinguished by attaching a subscript as in the following formulas (13) and (14).

  In addition, said Formula (13), (14) is called an interference removal calculation below.

  From the above formulas (13) and (14), the six-axis forces and moments Fx1 to Mz1 according to the first group and the six-axis forces and moments Fx2 to Mz2 according to the second group can be obtained. Since the voltage change of the output voltages V11 to V62 is very small due to the characteristics of the strain gauge, these output voltages are input to an amplifier such as an OP amplifier to appropriately expand the signal.

  Based on the six-axis force and moments Fx1 to Mz1 according to the first group and the six-axis force and moments Fx2 to Mz2 according to the second group, the six-axis force and The moments Fx, Fy, Fz, Mx, My, and Mz are calculated. Specifically, an average value of the six-axis forces and moments Fx1 to Mz1 according to the first group and the six-axis forces and moments Fx2 to Mz2 according to the second group is calculated. The six-axis forces and moments Fx, Fy, Fz, Mx, My, and Mz related to the output of the sensor 1 are assumed.

(Second calculation)
In the above first calculation, the output voltages of the six bridge circuits are simply amplified to obtain the six-axis forces and moments Fx, Fy, Fz, Mx, My, and Mz. On the other hand, in the second calculation, the output voltage of the six bridge circuits is converted in advance into an intermediate variable close to the six-axis force information, and then the above interference removal calculation is performed. According to this, the detection sensitivity of 6-axis force and moment Fx, Fy, Fz, Mx, My, and Mz can be improved. Hereinafter, the second calculation will be described in detail.

  First, from Table 1 above, the intermediate variables Fx10, Fy10, Fz10, Mx10, My10, and Mz10 are expressed by the following equation (15) using the resistance values of the strain gauges belonging to the first group. Ask.

  Similarly, from Table 1 above, the intermediate variables Fx20, Fy20, Fz20, Mx20, My20, Mz20 are expressed by the following equation (16) using the resistance values of the strain gauges belonging to the second group. Ask for it.

  The calculations of the above formulas (15) and (16) may be performed by directly measuring the resistance value of each strain gauge, and the resistance value is converted into a voltage value or a current value using an appropriate means (bridge circuit). You may go. Further, analog signals such as a resistance value, a voltage value, and a current value may be converted into a digital signal using an A / D converter, and then the calculations of the above formulas (15) and (16) may be performed. When each of the above operations is performed after making an A / D converter into a digital signal, it is preferable to use, for example, a microcomputer or a general-purpose PC.

  Here, focusing on (Rn1-Rn2) and (Rn3-Rn4) (where n = 1 to 6), which are the differences in resistance values in the above formulas (15) and (16), the flexibility around each resistance It can also be said that the inclination degree of the parts 111-116 and the coupling bodies 121-126 is represented. That is, by detecting the difference between the resistance values of two adjacent strain gauges in the first group and the second group due to the inclination of the flexible portions 111 to 116 and the coupling bodies 121 to 126, six axes for each group are detected. Force and moment Fx, Fy, Fz, Mx, My, and Mz can be obtained. Actually, rather than directly measuring and calculating the resistance values of the above equations (15) and (16), the half bridge shown in FIG. 8 is configured, and each of the bridge circuits is based on the output voltages V11 to V62. Since it is easier to calculate the six-axis forces and moments Fx, Fy, Fz, Mx, My, and Mz for each group and the essence of the operation is not lost, the method will be described below.

  11 and 12 are vector diagrams showing the output voltage of the bridge circuit. That is, when a force parallel to the flange 200 is applied, the amount of change (sensitivity) of the output voltages V11 to V62 is determined in consideration of the maximum strain gauge arrangement direction and the direction of change (increase / decrease). The vector diagrams of the voltages V11 to V62 are as shown in FIGS. Therefore, the force component parallel to the flange 200 acting on the flexible portions 111 to 116 can be expressed by the following equation (17).

  On the other hand, when a force perpendicular to the flange 200 is applied, the change directions (increase / decrease) of the output voltages V11 to V62 are the same. Therefore, the component of force perpendicular to the flange 200 acting on the flexible portions 111 to 116 can be expressed by the following equation (18).

  Among the six-axis forces and moments Fx, Fy, Fz, Mx, My, and Mz, the forces Fx, Fy, and moment Mz apply only the force of the component parallel to the flange 200, so Fx10 in the above equation (15), Fy10, Mz10 and the forces Fx20, Fy20 and moment Mz20 of the above equation (16) are the output voltages of the above equation (17), while the forces Fz, moments Mx and My are only forces having a component perpendicular to the flange 200. Since Fz10, Mx10, My10 of the above formula (15) and the force Fz20, moment Mx20, My20 of the above formula (16) can be replaced with the output voltage of the above formula (10).

  Therefore, the above formula (15) of the first group can be rewritten into the following formula (19).

  Similarly, the expression (16) of the second group can be rewritten as the following expression (20).

  Here, when the following equation (21) is applied such that Fx10 of the above equation (19) is substituted into V11 of the above equation (13), the above-mentioned equations (13) and (14) indicate that The axial force and moments Fx1 to Mz1 and the six axial force and moments Fx2 to Mz2 according to the second group can be obtained.

  Here, it should be noted that the above formulas (19) and (20) are addition / subtraction formulas for the multiple terms of the output voltages V11 to V62, and the sensitivity is higher than that of the first calculation. .

  Based on the six-axis force and moments Fx1 to Mz1 according to the first group and the six-axis force and moments Fx2 to Mz2 according to the second group, the six-axis force and The moments Fx, Fy, Fz, Mx, My, and Mz are calculated. Specifically, an average value of the six-axis forces and moments Fx1 to Mz1 according to the first group and the six-axis forces and moments Fx2 to Mz2 according to the second group is calculated. The six-axis forces and moments Fx, Fy, Fz, Mx, My, and Mz related to the output of the sensor 1 are assumed.

  In the foregoing, two types of operations for calculating the six-axis forces and moments Fx, Fy, Fz, Mx, My, and Mz based on the voltages V11 to V62 that are the outputs of the bridge circuit have been described.

  Next, the relationship between the measurement accuracy and obtaining two systems (ie, Fx1 to Mz1 and Fx2 to Mz2) of six-axis forces and moments will be described.

  First, basically, Fx1 to Mz1 and Fx2 to Mz2 should be equal. However, in practice, it is difficult to match all the forces and moments of the six axes. In particular, under actual usage conditions, a combined force in which forces or moments of two or more of the six axes are applied at the same time acts, and the load on a single axis for which the 6 × 6 characteristic matrices [A1] and [A2] are obtained. Since the conditions are different from each other, so-called combined force error increases, and errors occur in Fx1 to Mz1 and Fx2 to Mz2, respectively. As a result, Fx1 to Mz1 and Fx2 to Mz2 are difficult to match.

  The above problem will be specifically described below with reference to FIGS. 13 and 14. FIG. 13 is a schematic diagram of a testing machine for verifying the presence / absence of a complex force error. FIG. 14 is a graph illustrating the verification result of the combined force error. The 6-axis sensor shown in FIG. 13 is the same as the 6-axis sensor shown in FIG. 12 of JP-A-2008-96230, and the Z-axis of the 6-axis sensor is horizontal as shown in the figure. Rotating around the Z axis while holding The test result of the output characteristic is shown in FIG.

  In FIG. 13, a weight of 417 g is fixed to the 6-axis sensor at a portion corresponding to the flange 200 according to the above embodiment. In principle, the force components Fx and Fy and the moment components Mx and My change with considerable sensitivity corresponding to the Z-axis rotation phase of the 6-axis sensor, but the force Fz and moment Mz have zero output change. Should be. However, in practice, as shown in FIG. 14, the outputs of the force Fz and the moment Mz change corresponding to the Z-axis rotation phase. This is because the strain body structure is only spatially symmetrical with respect to the Z axis at 120 ° and is not line symmetric with respect to the X axis. Therefore, when the structure is rotated about the Z axis as shown in FIG. This is because the rigidity of the strain generating body changes. In short, since the strain body structure has poor symmetry, a compound force error occurs.

  On the other hand, the strain body of the six-axis sensor 1 according to the above embodiment is a target of 60 °, 120 °, and 180 ° about the Z axis, and is also symmetrical with respect to the X axis and the Y axis. Is symmetrical. Therefore, when the verification as shown in FIG. 13 is performed, there is an effect that the degree of change of the outputs of the force Fz and the moment Mz that should not change as shown in FIG. 14 corresponding to the Z-axis rotation phase can be reduced.

  Further, strain gauges R11 to R14, R31 to R34, R51 to R54 for detecting six-axis forces and moments Fx, Fy, Fz, Mx, My, and Mz, and strain gauges R21 to R24, R41 to R44. , R61 to R64 are arranged 180 ° symmetrically about the Z axis. Therefore, if the average values of the forces and moments Fx1 to Mz1 and Fx2 to Mz2 of the two systems are calculated as in the following formula (22), the compound force error is canceled by the symmetry of the strain gauge position, and more accurate six-axis Forces and moments Fx, Fy, Fz, Mx, My, Mz can be determined.

Next, based on FIG. 15, a configuration in which the six-axis sensor 1 according to the embodiment is embodied using a microcomputer will be exemplified. FIG. 15 is a block diagram of a 6-axis sensor.

  As shown in FIG. 15, the minute output voltage of the first group of bridge circuits (see also FIG. 8) is amplified using an appropriate amplifier 10 and then the A / D conversion terminal of the microcomputer 9. Is input. Similarly, a minute output voltage of the second group of bridge circuits (see also FIG. 8) is also amplified using an appropriate amplifier 11 and then input to the A / D conversion terminal of the microcomputer 9.

  The microcomputer 9 includes A / D converters 12 and 13 shown in the figure, an interference cancellation calculation unit 14 (first force moment calculation means), an interference cancellation calculation unit 15 (second force moment calculation means), and an output calculation. A unit 16 (output calculation unit), a determination unit 17 (determination unit), and an abnormal process execution unit 18 (abnormal process execution unit) are included.

  Further, the microcomputer 9 includes an unillustrated CPU (Central Processing Unit), a RAM (Random Access Memory), and a ROM (Read Only Memory). The ROM of the microcomputer 9 stores a program that causes the CPU to function as the interference removal calculation unit 14, the interference removal calculation unit 15, the output calculation unit 16, the determination unit 17, and the abnormality processing execution unit 18. Then, by reading this program into the CPU and executing it, the microcomputer 9 functions as the interference removal calculation unit 14 and the like.

  The A / D converter 12 converts the output voltage of each bridge circuit amplified by the amplifier 10 into a digital signal. The same applies to the A / D converter 13.

  The interference removal calculating unit 14 obtains six-axis forces and moments Fx1 to Mz1 based on the output result (output voltage) of the first group. The interference removal calculating unit 15 obtains six-axis forces and moments Fx2 to Mz2 based on the output result (output voltage) of the second group.

  The output calculation unit 16 includes the first group of six-axis forces and moments Fx1 to Mz1 obtained by the interference removal calculation unit 14, and the second group of six-axis forces and moments Fx2 obtained by the interference removal calculation unit 15. Based on ˜Mz2, 6-axis forces and moments Fx to Mz as outputs of the 6-axis sensor 1 are calculated. Specifically, an average value of Fx1 to Mz1 and Fx2 to Mz2 is calculated, and the average value is set as a six-axis force and moments Fx to Mz related to the output of the six-axis sensor 1. The calculation result of the output calculation unit 16 is transmitted to a control device (not shown).

  The determination unit 17 compares the forces and moments Fx1 to Mz1 related to the interference cancellation calculation unit 14 with the forces and moments Fx2 to Mz2 related to the interference cancellation calculation unit 15 and opens a predetermined amount or more between them. Determine if there is any. The predetermined amount may be set, for example, as a few percent of the calculation result of the interference removal calculation unit 14 or the interference removal calculation unit 15.

  If the determination unit 17 determines that there is an opening of a predetermined amount or more between the two, the abnormal process execution unit 18 executes a predetermined abnormal process. As the “predetermined abnormality process”, for example, a warning lamp (not shown) is preferably blinked or a warning buzzer is sounded.

  Next, the operation of the 6-axis sensor 1 will be described. First, the minute output voltages V11 to V52 of each bridge of the first group of the six-axis sensor 1 (see also FIG. 8) are amplified by the amplifier 10 and then converted into digital signals by the A / D converter 12. Convert. Next, the interference cancellation calculation unit 14 obtains Fx1 to Mz1 based on the output voltages V11 to V52 by executing the interference cancellation calculation based on the above equation (13).

  Similarly, after the amplifier 11 appropriately amplifies the minute output voltages V21 to V62 of each bridge (see also FIG. 8) of the second group of the 6-axis sensor 1, the A / D converter 13 converts the digital signal into a digital signal. Convert to Next, the interference cancellation calculation unit 15 obtains Fx2 to Mz2 based on the output voltages V21 to V62 by executing the interference cancellation calculation based on the above equation (14).

Next, the determination unit 17 compares Fx1 and Fx2, and determines whether, for example, the absolute value of (Fx1-Fx2) is below a threshold value that is 5% of Fx1. The determination unit 17 similarly determines Fy1 and Fy2, Fz1 and Fz2,. If the determination unit 17 determines that the absolute value is lower than the threshold value in any comparison, the output calculation unit 16 sets Fx1 and Fx2, Fy1 and Fy2,... The average value is transmitted to the control device (not shown) as the six-axis forces and moments Fx to Mz of the six-axis sensor 1.

  On the other hand, if the determination unit 17 determines that the absolute value is not lower than the threshold value in any of the comparisons, the abnormal process execution unit 18 stops the system operation, for example, or displays a warning lamp. Abnormal processing such as blinking is executed.

  As described above, in the above embodiment, the 6-axis sensor 1 is configured as follows. That is, the 6-axis sensor 1 includes a flange 100 (first member) having flexible portions 111 to 116 (first flexible portion) in which a plurality of strain gauges (strain detection elements) are arranged, and the flexible portion 111. ˜116 and a flange 200 (second member) having flexible portions 211 to 216 (second flexible portion) opposed to each other, and coupling bodies 121 to 126 and 221 to 226 that connect the flange 100 and the flange 200. Is provided.

  The plurality of strain gauges (for example, strain gauges R11 to R14), the flexible portion (for example, the flexible portion 111), the second flexible portion (for example, the flexible portion 211), and the connection body (for example, the connection body 121, As shown in FIG. 1, the groups composed of 221) are arranged in six groups at equal intervals on the arc.

  The 6-axis sensor 1 includes an interference removal calculation unit 14 (first force / moment calculation means) for obtaining 6-axis force and moment based on an output result from a set selected by skipping one of the plurality of sets. The interference removal calculation unit 15 (second force moment calculation means) for obtaining six-axis forces and moments based on the output results from the remaining sets of the plurality of sets and the interference removal calculation unit 14 Based on the six-axis forces and moments and the six-axis forces and moments obtained by the interference cancellation calculation unit 15, the six-axis forces and moments as the output of the six-axis sensor 1 are calculated. And an output calculation unit 16 (output calculation means). According to the above configuration, the strain gauges (R11-14, R31-34, R51-54) belonging to the former group and the strain gauges (R21-24, R41-44, R61) belonging to the latter group. ˜64), the aforementioned compound force error is mitigated.

  The six-axis sensor 1 is further configured as follows. That is, the output calculation unit 16 calculates an average value of the force and moment related to the interference cancellation calculation unit 14 and the force and moment related to the interference cancellation calculation unit 15, and calculates the average value. , And the force and moment related to the output of the six-axis sensor 1. According to the above configuration, the strain gauges (R11-14, R31-34, R51-54) belonging to the former group and the strain gauges (R21-24, R41-44, R61) belonging to the latter group. ˜64), the aforementioned compound force error is strongly canceled out.

  The six-axis sensor 1 is further configured as follows. That is, the 6-axis sensor 1 compares the force and moment related to the interference cancellation calculation unit 14 with the force and moment related to the interference cancellation calculation unit 15, and the both are opened by a predetermined amount or more. When the determination unit 17 (determination unit) that determines whether or not there is an opening of a predetermined amount or more between the determination unit 17 and the abnormality processing execution unit 18 (abnormal processing execution) that executes predetermined abnormality processing Means). According to the above configuration, since the failure of the strain gauge (R11 to R64) can be detected, the reliability of the six-axis sensor 1 is improved.

  The six-axis sensor 1 is further configured as follows. That is, the set is arranged in six sets. According to the above configuration, the manufacturing cost can be reduced because the configuration is simple.

  Since the above-mentioned 6-axis sensor 1 simply arranges all strain gauges on a flat surface, it can easily realize the work of attaching strain gauges that require manual labor and can ensure high productivity. .

  In addition, if it adds, the 6-axis sensor 1 which concerns on the said embodiment is provided with a connection body more than twice compared with the structure shown by FIG. Thereby, since the amount of distortion per each flexible part becomes small, the measurement range of 6-axis forces and moments Fx to Mz is expanded.

  The preferred embodiment of the present invention has been described above, but the above embodiment can be modified as follows.

  That is, in the above embodiment, the six-axis sensor 1 is provided with six sets of flexible portions that are paired with the flange 100 and the flange 200. However, the present invention is not limited to this. For example, the flexible portion to be paired with the flange 100 and the flange 200 is 2 m at an equal interval and an equal angle around the Z axis (where m is an integer of 3 or more) ), A configuration to be provided is conceivable. Even in this configuration, it is possible to detect two systems of six-axis forces and moments Fx1 to Mz1 and Fx2 to Mz2.

  Hereinafter, the operation of the six-axis sensor 1 when m = 4 in the above modification will be briefly described. In other words, in such a case, there are 16 half-bridge circuits composed of a plurality of strain gauges, and 16 output voltages can be obtained from the 16 half-bridge circuits. Based on the 16 output voltages, intermediate signals Fx10 to Mz10 and Fx20 to Mz20 are obtained in the manner of the above formulas (19) and (20). Further, assuming that Fx10 to Mz10 are V11 to V52 and Fx20 to Mz20 are V21 to V62, the six-axis force as the output of the six-axis sensor 1 is obtained according to the above formulas (13), (14), and (22). And moments Fx to Mz are calculated.

  Thus, when the said group is arrange | positioned by 8 sets, there exist the following effects. That is, the 6-axis sensor 1 has point symmetry of 22.5 °, 67.5 °, 112.5 °, and 157.5 ° about the Z axis, and is line symmetric with respect to the X axis and the Y axis. Exhibits excellent symmetry. Therefore, one aspect of the combined force error can be further reduced.

  By utilizing the present invention, it is possible to obtain a multi-axis sensor capable of reducing the combined force error as compared with the prior art and capable of accurately detecting the six-axis force and moment.

It is the top view on which arrangement of each flexible part was drawn. It is arrow sectional drawing of the AA line shown in FIG. It is arrow sectional drawing of the BB line shown in FIG. It is explanatory drawing which shows the detection operation | movement of distortion at the time of applying a force and a moment to a flange. It is explanatory drawing which shows the detection operation | movement of distortion at the time of applying a force and a moment to a flange. It is explanatory drawing which shows the detection operation | movement of distortion at the time of applying a force and a moment to a flange. It is explanatory drawing which shows the detection operation | movement of distortion at the time of applying a force and a moment to a flange. It is explanatory drawing which showed the circuit diagram of six bridge circuits comprised in each flexible part, and those positional relationship. It is a vector diagram which shows the output voltage of a bridge circuit. It is a vector diagram which shows the output voltage of a bridge circuit. It is a vector diagram which shows the output voltage of a bridge circuit. It is a vector diagram which shows the output voltage of a bridge circuit. It is the schematic of the testing machine for verifying the presence or absence of compound force error. It is a graph which shows the verification result of compound force error. It is a block diagram of a 6-axis sensor.

1 6-axis sensor (multi-axis sensor)
14 Interference Removal Calculation Unit 15 Interference Removal Calculation Unit 16 Output Calculation Unit 17 Determination Unit 18 Abnormal Processing Execution Unit 100 Flange (First Member)
111-116 Flexible part (first flexible part)
121-126, 221-226 connector 200 flange (second member)
211-216 Flexible part (second flexible part)
R11 to R64 Strain gauge (force detection element)

Claims (6)

A first member having six first flexible portions in which a plurality of strain detection elements are disposed;
A second member having a second flexible portion facing each of the first flexible portions;
A connecting body for connecting the first flexible portion and the second flexible portion;
A multi-axis sensor comprising force-moment calculating means for calculating six-axis forces and moments based on output results of the plurality of strain detection elements. A first member having a plurality of first flexible portions in which a plurality of strain detection elements are disposed;
A second member having a second flexible portion facing each of the first flexible portions;
A connecting body for connecting the first flexible portion and the second flexible portion;
Force moment calculating means for calculating six-axis forces and moments based on the output results of the plurality of strain detection elements;
The first flexible part, the second flexible part, and the coupling body are equiangular around the central axis in the first member and the second member, and are equidistant from the central axis. Divided into an even number of 6 or more sets formed in
The force moment calculating means includes
First force / moment calculation means for calculating six-axis forces and moments based on output results of the plurality of strain detection elements from a set selected by skipping one of the even sets;
Second force moment calculating means for calculating six-axis forces and moments based on output results of the plurality of strain detection elements from the remaining sets of the even number sets;
6-axis force and moment are calculated based on the 6-axis force and moment calculated by the first force-moment calculating means and the 6-axis force and moment calculated by the second force-moment calculating means. A multi-axis sensor comprising an output calculation means. The output calculation means includes
The average value of the six-axis force and moment calculated by the first force-moment calculation means and the six-axis force and moment calculated by the second force-moment calculation means is calculated as the six-axis force and moment. The multi-axis sensor according to claim 2. The six-axis force and moment calculated by the first force-moment calculating means are compared with the six-axis force and moment calculated by the second force-moment calculating means, and the comparison result is a predetermined amount or more. Determination means for determining whether or not,
The multi-axis sensor according to claim 2, further comprising an abnormality process executing unit that executes a predetermined abnormality process when the determination unit determines that the comparison result is equal to or greater than a predetermined amount. . The multi-axis sensor according to any one of claims 2 to 4, wherein the even number set is six sets. The multi-axis sensor according to any one of claims 2 to 4, wherein the even number set is eight sets.

Images