End effector for wall surface inspection with compliance mechanism

Abstract

This invention provides an end effector equipped with a compliance mechanism that allows the wall inspection device to stably contact the wall inspection point in the normal direction and autonomously maintain the correct posture while following variations in the wall shape. [Solution] The present invention comprises a compliance mechanism (110) attached to an operating arm (A) via a support base (100), and a support frame (120) supported by this mechanism and housing a wall inspection device (130). The compliance mechanism (110) is composed of a plurality of elastic support means (113) arranged at equiangled positions on the circumference with respect to the center of the support base (100), and each telescopic axis (L) is inclined to converge and intersect toward the wall inspection point (P). Furthermore, contact means (140) are arranged on the wall side of the support frame (120) at equiangled positions centered on the inspection point (P) to form a three-point support, ensuring stable contact and followability with respect to the wall surface (W).

Description

Technical Field

[0001] The invention according to the present application (hereinafter referred to as "the present invention") relates to an end effector for wall inspection attached to the tip of a robot arm or the like for inspecting the state of the wall surface of a structure. In particular, it relates to a configuration in which an inspection device is autonomously aligned in the normal direction with respect to a wall inspection point by providing a compliance mechanism.

Background Art

[0002] As a conventional wall inspection device, for example, in Patent Document 1, a tapping device for inspecting floating of a wall surface or the like is disclosed. In this device, an operator makes a solenoid-driven knock piece abut against the wall surface and listens to the reverberation sound, and the holding in the striking direction depends on the manual operation of the operator. Since a one-axis support mechanism is adopted, it does not have a compliance mechanism for always maintaining the normal direction (vertical direction) with respect to the wall surface.

[0003] Further, Patent Document 2 discloses a tapping inspection device provided with a moving mechanism, but there is no mechanism for autonomously adjusting the striking direction with respect to wall irregularities and inclinations, and there is a problem that the striking posture is not stable.

[0004] Furthermore, as a non-destructive inspection method, an internal inspection device using electromagnetic waves is known, and Patent Document 3 discloses a configuration in which a transmitting and receiving antenna is pressed against a wall surface to measure the internal state. However, the antenna posture depends on the holding by an operator or a fixed jig, and it does not have an end effector structure for stably holding the normal direction N of the wall surface.

[0005] Also, Patent Document 4 discloses an inspection device for measuring the degree of reinforcement corrosion using ultrasonic waves. However, the contact posture when pressing the probe against the wall surface depends on manual holding, and a mechanism for aligning it in the normal direction N with respect to the wall surface is not disclosed. There is a problem that when the probe is slightly tilted, the adhesion state of the ultrasonic coupling agent becomes non-uniform, and the measurement reproducibility decreases due to fluctuations in the reflected wave intensity.

Prior Art Documents

[0006] [Patent Document 1] Japanese Patent Application Publication No. 5-164749 [Patent Document 2] Japanese Patent Publication No. 2021-96115 [Patent Document 3] Japanese Patent Publication No. 2010-204055 [Patent Document 4] Japanese Patent Publication No. 2007-121123 [Overview of the project] [Problems that the invention aims to solve]

[0007] Although the conventional technologies described above incorporate various improvements to the inspection method itself, they all share a common problem: they lack an end-effector structure to stably hold the inspection device in the normal direction N at the inspection point when the inspection device is used in contact with a wall.

[0008] In particular, the system could not adjust its contact posture to follow localized irregularities and slopes on the wall surface, and the contact posture depended on the operator's holding position, resulting in significant fluctuations in measurement accuracy and reproducibility. Furthermore, when these inspection devices were mounted on the tip of a robot arm, maintaining the normal alignment at the inspection point became even more difficult due to arm posture errors and minute vibrations.

[0009] In view of these problems, the present invention aims to provide an end effector for wall surface inspection that is equipped with a compliance mechanism, autonomously aligns the inspection device in the normal direction N with respect to the wall surface inspection point, and stably maintains the device while absorbing wall surface irregularities, inclination, and arm posture errors. [Means for solving the problem]

[0010] To solve the above problems, the present invention is configured as follows. According to the present invention, a compliance mechanism is attached to the tip of the operating arm via a support base, It consists of a support frame supported via the compliance mechanism and having a wall inspection device installed inside, The compliance mechanism connects the support base and the support frame via elastic support means attached at least three times at equal angular intervals in the circumferential direction with respect to the center of the support base, and is configured such that each of the elastic support means is inclined to converge and intersect toward the wall inspection point of the wall inspection device. The support frame is characterized in that contact means are provided at least three times on the wall side, corresponding to equiangular positions on the circumference with respect to the wall inspection point.

[0011] The compliance mechanism connects the support base and the support frame by at least three elastic support means arranged at equiangled positions on the circumference with respect to the center of the support base, and the extension axes of these elastic support means are inclined to converge and intersect toward the wall inspection point.

[0012] Furthermore, contact means are arranged on the wall side (bottom side) of the support frame at equi-angled positions on the circumference, centered on the wall inspection point.

[0013] The elastic support means can be supported at peripheral positions on a line perpendicular to the center of the support base and at positions closer to the center of the support frame, and can be configured by a coil spring, leaf spring, elastic bush, or air cushion, or a combination thereof.

[0014] Furthermore, the support base is equipped with a 3D camera for imaging the area around the wall inspection point, and the wall inspection device can be appropriately selected and mounted as a wall inspection device, such as a tapping sound inspection device, a wall drilling device, an electromagnetic wave measuring device, an ultrasonic exploration device, or a laser-type wall inspection device. [Effects of the Invention]

[0015] According to the present invention, a plurality of elastic support means are disposed obliquely between a support base and a support frame, and their expansion and contraction axes are focused toward the wall inspection point, so that the support frame and the inspection device provided therein can be automatically aligned in the normal direction N of the inspection point. As a result, fluctuations in the contact posture due to local unevenness of the wall surface or posture errors of the operation arm can be suppressed, and a stable inspection posture can be ensured.

[0016] In addition, by supporting the elastic support means at a peripheral position of the support base and a position closer to the center of the support frame and arranging them in an inclined state, an appropriate restoring force is applied to the support frame, and the posture holding performance is improved.

[0017] Furthermore, by appropriately combining the configurations described in the dependent claims such as the type of elastic support means, the configuration of the contact means, the floating mechanism, the spring biasing mechanism, the proximity sensor, the 3D camera, etc., the contact stability with the wall surface, the uniformization of the pressing state, the ease of inspection alignment, and the improvement of visibility can be achieved, and the operability and adaptability of the inspection device can be enhanced.

Brief Description of the Drawings

[0018] [Figure 1] It is a front view of the first embodiment. [Figure 2] It is a perspective view from above of the first embodiment. [Figure 3] It is a front view of the second embodiment. [Figure 4] It is a perspective view from above of the second embodiment. [Figure 5] It is a bottom view of the second embodiment. [Figure 6] It is a perspective view from below of the second embodiment. [Figure 7] It is a partially cutaway enlarged view of the portion surrounded by E in FIG. 3. [Figure 8] It is a schematic diagram showing the operation process of the second embodiment, (A) shows the state when contacting the wall surface, and (B) shows the state when the compliance mechanism is operating.

Modes for Carrying Out the Invention

[0019] Firstly, since the embodiment of the present invention is an end effector that is attached to the tip of a robot arm A and moves freely, there are no defined up, down, left, or right directions for the device. However, for convenience, in the following description, the side that contacts the wall surface during inspection will be defined as the bottom surface, and the front view and top view (plan view) will be defined based on this, with up, down, left, and right defined relative to this front view. Furthermore, the structural positioning of each embodiment in the present invention can be clarified as follows. In other words, the first embodiment shows the basic configuration of the present invention, consisting of a compliance mechanism 110, a support frame 120, and a contact means 140, and specifically shows the minimum configuration for aligning the wall surface inspection device 130 with respect to the wall surface in the normal direction N. In contrast, the second embodiment is an applied structure that adds a tapping sound inspection device 500 to the configuration of the first embodiment, and further adds a floating mechanism 600, integrating advanced functions such as uniform pressure and posture detection of the tapping sound inspection device 500. (1) First Embodiment

[0020] The first embodiment comprises a support base 100, a compliance mechanism 110, a support frame 120, a wall inspection device 130, and a contact means 140, which are the defining features of the wall inspection end effector according to the present invention, and will be described below with reference to Figures 1 and 2. (1-A) Support base

[0021] The support base 100 is formed from a square-shaped, thick, rigid plate, and the operating arm A is detachably attached to its center by a plurality of fastening bolts 101. This support base 100 is made of a thick, rigid material such as aluminum alloy or stainless steel, and stabilizes the reference coordinate system of the compliance mechanism 110.

[0022] The mounting method to the operating arm A in the first embodiment is not particularly limited, and known mounting mechanisms such as clamp coupling, flange coupling, and quick changer may be used as appropriate.

[0023] Furthermore, in the first embodiment, the support base 100 is approximately square in shape when viewed from above, but it is not limited to this and may be circular or a regular polygon. (1-B) Compliance mechanism

[0024] Coil springs 111 are used as elastic support means at the edges (square corners) in a cross direction from the center of the support base 100, and their upper ends are pivotally supported via upper connecting hooks 112. The lower ends of the coil springs 111 are pivotally supported via lower connecting hooks 113 to a mounting base 114 located on the upper frame plate 121, which will be described later. These four coil springs 111 connect the support base 100 and the support frame 120.

[0025] The four coil springs 111 described above are mounted with a tensile biasing force. Furthermore, each coil spring 111 is mounted at an angle such that its respective extension axis L converges and intersects toward the wall inspection point P described later. Here, the term "expansion axis" refers to the axis that defines the direction of expansion and contraction of the elastic support means.

[0026] Furthermore, the coil springs 111 are not limited to the four locations shown in the figure; any arrangement that can stably maintain the central vertical axis is acceptable, as long as they are at equiangled positions on the circumference centered on the center of the support base 100.

[0027] The expansion, contraction, and deflection of the coil spring 111 cause the compliance mechanism 110, which adjusts the positional relationship of the wall inspection device 130 with respect to the wall surface W, to function and contribute to maintaining the normal direction N with respect to the wall surface.

[0028] Furthermore, the essence of this configuration lies in the fact that the expansion and contraction axes L of each elastic support means intersect toward the wall inspection point P, thereby geometrically constraining the pivot center of the support frame 120 to P.

[0029] Therefore, even if the support frame 120 experiences elastic deformation and misalignment in the roll and pitch directions, its orientation naturally converges to the normal direction N at the wall inspection point P. This allows the contact direction of the inspection device to be stably maintained while absorbing irregularities in the wall W and orientation errors of the operating arm A.

[0030] Furthermore, in addition to the coil spring 111, other elastic materials with linear expansion and contraction characteristics, such as leaf springs, elastic bushings, or air cushions, may be used as elastic support means. (1-C) Support frame

[0031] The support frame 120 is supported by the four coil springs 111, and the square-shaped upper frame plate 121 and the larger square-shaped lower frame plate 122 are connected by columnar supports 123 positioned near the corners, forming the internal space for the wall inspection device 130.

[0032] Furthermore, the lower frame plate 122 has a through-hole 124 in its center, which allows the inspection section (bottom side) of the wall inspection device 130 to be positioned close to and facing the wall inspection point P.

[0033] Furthermore, the support frame 120 is not limited to the above-described form; it may also be formed in a box shape using a monocoque structure machined from a single piece of material, or aluminum or reinforced plastic. (1-D) Wall surface inspection device

[0034] The wall inspection device 130 is exposed to the wall surface W side through the through-hole 124 of the lower frame plate 122, and is detachably attached to the upper surface of the lower frame plate 122 with L-shaped brackets 131 around its sides.

[0035] Furthermore, this wall inspection device 130 can be applied to wall drilling devices, electromagnetic wave measuring devices, ultrasonic exploration devices, or laser-type wall inspection devices, in addition to the impact sound inspection device described later.

[0036] For example, in the case of the impact sound testing device 500 described later, the transmission of impact energy is optimized by the impactor contacting the normal direction N, thereby improving the reproducibility of the reverberation sound.

[0037] In the case of a wall-drilling device (drawing not shown), the force applied to the cutting edge is stable in the vertical direction, which suppresses uneven wear and prevents tilting of the drilling axis and the occurrence of elliptical drilling.

[0038] Furthermore, in the electromagnetic wave measuring device (drawing not shown), maintaining the incident angle of the electromagnetic wave in the normal direction N stabilizes the reflectance and transmittance, improving the accuracy of detecting internal defects.

[0039] Similarly, in the case of an ultrasonic inspection device (diagram omitted), optimizing the incident angle of ultrasound maximizes the reflected echo from defects, improving the sensitivity of detecting delamination and cavities.

[0040] Furthermore, in the case of a laser-type inspection device (drawing omitted), the emitted light is accurately reflected back to the light-receiving unit, which reduces noise in the distance measurement and stabilizes the measurement accuracy.

[0041] Since these wall inspection devices 130 themselves use standard commercially available products, a detailed explanation of their internal mechanisms will be omitted. 1-E. Contact means In the first embodiment, the lower frame plate 122 of the support frame 120 functions as a contact means 140.

[0042] Columnar contact means 140 are suspended from the lower surface of the corners (4 locations) of the lower frame plate 122 to create a predetermined gap between it and the wall surface W. The reason for creating this gap between the lower frame plate 122 and the wall surface W is to prevent a part of the wall surface inspection device 130 from coming into contact with the wall surface W, even if the lower frame plate 122 is inclined against the wall surface during contact.

[0043] Contact between the contact means 140 and the wall surface W may be avoided by placing a contact sensing sensor (not shown in the drawing), or by a control program for the operating arm A.

[0044] Furthermore, a coil spring (not shown) may be externally attached to the contact means 140, similar to the second embodiment described later, to constitute a floating mechanism (not shown). (1-F) Effects of the first embodiment

[0045] With the above configuration, the first embodiment causes the contact means 140 to come into contact with the wall surface (initial contact) by linearly operating the operating arm A toward the wall surface inspection point P. At this time, if contact at least three points of the contact means 140 is not detected, the linear operation of the operating arm A is continued until contact at least three points is detected, and the operation of the operating arm A is stopped and held in the detected state.

[0046] If initial contact is not detected at these three points, the compliance mechanism 110 functions through the expansion and contraction and deflection of each of the four coil springs 111, and the inspection area of ​​the wall inspection device 130 becomes the normal direction N.

[0047] The four coil springs 111, which constitute the compliance mechanism 110 as elastic support means, are arranged so that their respective expansion and contraction axes L converge and intersect toward the wall inspection point P, thereby producing the following effects.

[0048] a) Even if the support frame 120 swings, the swing becomes a spherical rotation around the wall inspection point P, making it less likely for the contact direction of the wall inspection device 130 to deviate from the normal direction N of the wall W, thereby improving the accuracy of inspection methods where the direction of incidence affects the measurement accuracy, such as impact sound, ultrasound, and laser.

[0049] (i) Because the expansion and contraction axes L of the elastic support means intersect, the mounting points of each coil spring 111 on the support frame 120 side (upper connecting hook 112 and lower connecting hook 113) are constrained from multiple directions, and the lateral sliding degree of freedom of the support frame 120 is suppressed. As a result, the tip of the inspection device is less likely to deviate laterally from the wall inspection point P, and highly accurate single-point measurements can be performed repeatedly and stably.

[0050] (c) The equiangled arrangement equalizes the restoring force, improving posture stability. No matter which direction the support frame 120 tilts, the restoring force acts evenly, preventing the entire device from tipping over in an unbalanced direction, and maintaining a stable posture at all times. (2) Second Embodiment

[0051] Next, the second embodiment will be described in detail with reference to the drawings. In the second embodiment, a tapping inspection device 500 is attached as the wall surface inspection device 130 of the first embodiment described above, and a contact plate 603 is arranged in a floating state on the bottom side of the lower frame plate 402 of the support frame 400. (2-A) Support base

[0052] The support base 200 is formed from a square-shaped, thick, rigid plate, similar to the first embodiment, and has a bolt hole 201 in its center for fixing the operating arm A.

[0053] Furthermore, a 3D camera 202 (for example, a stereo camera or a time-of-flight camera) is attached to the outer part of the support base 200. This 3D camera 202 is used to acquire three-dimensional information of the area near the inspection wall surface and is useful for analyzing the control of the operating arm A. (2-B) Compliance mechanism

[0054] The support base 200 is provided with support pieces 301 that are inclined downward in a cross shape outward from the midpoint of each side. A coil spring 302, which serves as an elastic support means, is attached to the tip of each of these support pieces 301. These four coil springs 302 connect the upper frame plate 401, which is located above the support frame 400, and the support base 200 with a tensile biasing force.

[0055] Each coil spring 302 is mounted at an angle, similar to the first embodiment described above, so that its respective extension axis L converges and intersects with the striking point P (wall inspection point) of the hammer 501 of the impact sound inspection device 500.

[0056] With this configuration, the expansion, contraction, and deflection of the four inclined coil springs 302 cause the compliance mechanism 300 to function, adjusting the striking stroke of the hammer 501 against the wall W to be in the normal direction N. (2-C) Support frame

[0057] The support frame 400 is connected to the support base 200 by the four coil springs 302 described above, and the square upper frame plate 401 and lower frame plate 402 are connected near their corners by four rod-shaped support columns 403 to form a three-dimensional structure.

[0058] The upper frame plate 401 has mounting bases 404 for attaching the coil spring 302 formed at positions closer to the center of the square, extending from the midpoints of each side of the square. The coil spring 302 is connected in an inclined state to these mounting bases 404 and to the tips of the support pieces 301 that extend outward from the midpoints of the four sides of the support base 200.

[0059] The lower frame plate 402 has a through-hole 405 in its center for attaching a tapping sound testing device 500.

[0060] Furthermore, columnar legs 406 are attached in a hanging manner to the corners on the back side of the lower frame plate 402. These legs 406 are intended to prevent contact between the open bottom 502 of the impact sound testing device 500 and the wall surface W due to the tilting of the contact plate 600, which will be described later, in the floating state. The height of these legs 406 is adjusted as appropriate according to the condition of the wall surface W. (2-D) Percussion testing device

[0061] The second embodiment is configured with a sound-impact inspection device 500 attached as a wall surface inspection device. Its appearance is that of a roughly rectangular cylinder, and its bottom side is held in a state where it extends from the through-hole 405 of the lower frame plate 402. Its bottom side is open toward the wall surface W. This sound-impact inspection device 500 is equipped with a hammer 501 for striking that moves in a straight line by a solenoid plunger mechanism, and a microphone 503 for picking up the sound of the impact reflection.

[0062] Since the mechanism of this impact sound testing device 500 is based on publicly known technology, its detailed configuration will be omitted. (2-E) Floating mechanism

[0063] A contact plate 601, which serves as a contact means, is attached to the lower surface of the lower frame plate 402 by a floating mechanism 600. The floating mechanism 600 is constructed by fixing four roughly U-shaped brackets 504, which are attached to the four sides of the edge of a through-hole 405 formed in the lower frame plate 402, to the four sides of the impact sound testing device 500, and connecting them to the contact plate 601 via a coil spring 602.

[0064] When the operating arm A is moved and comes into contact with the wall surface W, the contact pressure causes the contact plate 601 to tilt due to the individual expansion and contraction amounts of each coil spring 602. The coil spring 602 is not limited to this; other resilient materials such as leaf springs, torsion bars, rubber bodies, or air cushions may also be used.

[0065] Furthermore, the contact plate 601 is provided with contact portions 603 that protrude toward the wall surface W at equiangled positions on the circumference centered on the point of impact P. In the second embodiment, the contact portion 603 is arranged at the four corners of a square shape, but it is not limited to this, and may be formed in a regular polygonal shape as long as the center during tilting is maintained.

[0066] In the above configuration, a proximity sensor 700 is placed near the contact portion 603 attached to the contact plate 601. This proximity sensor 700 measures the distance to the upper surface of the contact plate 601 and detects the tilting state of the contact plate 601. Based on the detection of distances at at least three locations, it is determined that the forward and backward axis (or striking direction) of the hammer 501 installed inside the impact sound inspection device 500 is in the direction N normal to the wall surface W.

[0067] At this point, the operation of the control arm A is stopped, and the hammer 501 is activated to strike the wall W. Simultaneously, the reverberation sound produced by the strike is collected by the microphone 503 to determine the conditions inside the wall.

[0068] Alternatively, instead of the proximity sensor 700, a known sensing sensor such as a microswitch, limit switch, or piezoelectric element sensor may be provided at the contact portion 603. (2-F) Effect The operation of the second embodiment with the above configuration will be explained with reference to Figure 8.

[0069] First, the impact point P, which will be the wall inspection point, is identified by measuring the position of the 3D camera 202, and the operating arm A is moved (linearly) toward that position (see arrow S in Figure 8(A)). Since the object being inspected is the inner wall surface of a tunnel that extends in an arch shape, initial contact rarely occurs with all points of the contact portion 603 making contact simultaneously and evenly (arrow C).

[0070] Therefore, the operating arm A is moved in one swift motion to push in the end effector until the proximity sensor 700 detects contact at least three points on the contact portion 603 (arrow F). During this pushing process from the initial contact before the three points of contact are reached (arrow λ), the compliance mechanism 300 with the above configuration functions. That is, the coil spring 302 undergoes a combined deformation of bending, compression, and tilting, causing the support frame 400 to tilt at a small angle (arrow α), pushing in until at least three points of the contact portion 603 contact the wall surface W (Figure 8(B), arrow F).

[0071] The expansion and contraction axes L of the four coil springs 302 are arranged to converge and intersect at the impact point P. As the spring deflection and tilting of the support frame 400 associated with the pressing process converge, the tangent plane of the impact point on the wall surface W is geometrically defined. The control system uniquely determines the normal direction N at the impact point P using geometric information and stabilization of contact detection. [Explanation of symbols]

[0072] A Operating Arm S Operating arm linear movement F Push in the operating arm C Clearance from the exterior wall surface L Telescopic axis N normal direction W Wall P Wall surface inspection point (impact point) 100, 200 support base 110,300 Compliance Organization 111, 302 Coil spring (elastic support means) 120, 400 support frame 121, 401 Upper frame board 122, 402 Lower frame plate 123, 403 pillars 130 Wall surface inspection device 140 Contact means 202 3D cameras 404 Mounting base 405 Through-hole 406 Pillar 500 Percussion Testing Device 504 Bracket 600 Floating Mechanism 601 Contact plate 603 Contact part 700 proximity sensors

Claims

1. An end effector for wall surface inspection, equipped with a compliance mechanism attached to the tip of an operating arm, A compliance mechanism is attached to the tip of the operating arm via a support base, It consists of a support frame supported via the compliance mechanism and having a wall inspection device installed inside, The compliance mechanism connects the support base and the support frame via elastic support means attached at least three times at equal angular intervals in the circumferential direction with respect to the center of the support base, and is configured such that each of the elastic support means is inclined to converge and intersect toward the wall inspection point of the wall inspection device. An end effector for wall surface inspection, characterized in that the support frame has a compliance mechanism in which contact means are arranged at least three locations on the wall side corresponding to equiangular positions on the circumference with respect to the wall surface inspection point.

2. The wall surface inspection end effector equipped with the compliance mechanism according to claim 1, characterized in that the elastic support means is supported at a peripheral position on a line perpendicular to the center of the support base at one end in the extension direction, and at a position closer to the center of the support frame at the other end, and is arranged in an inclined state.

3. The wall surface inspection end effector equipped with a compliance mechanism according to claim 1, characterized in that the elastic support means is composed of a coil spring, a leaf spring, an elastic bush, or an air cushion, or a combination thereof.

4. The wall surface inspection end effector according to claim 1, characterized in that the contact means is provided with a floating mechanism.

5. The wall surface inspection end effector equipped with the compliance mechanism according to claim 4, characterized in that the floating mechanism is configured to resiliently bias by arranging a spring mechanism at the contact portion of the contact means.

6. The wall surface inspection end effector according to claim 1, characterized in that a proximity sensor for detecting the distance to the wall surface is provided in the contact means.

7. The wall surface inspection end effector equipped with a compliance mechanism according to claim 1, characterized in that a 3D camera for imaging the area near the wall surface inspection point is installed on the support base.

8. The wall surface inspection end effector equipped with a compliance mechanism according to any one of claims 1 to 7, characterized in that the wall surface inspection device is one of a tapping sound inspection device, a wall surface drilling device, an electromagnetic wave measuring device, an ultrasonic exploration device, or a laser-type wall surface inspection device.

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