Hole measuring device and method for measuring hole

Abstract

Provided is an automatic hole measuring device and a method for automatically measuring a hole which are low-cost and simple yet realizes accuracy and stability comparable to human labor. This hole measurement device is provided with: a hole contact unit for driving a plurality of probes forward and backward so as to bring the plurality of probes into contact with an inner surface of a hole to be measured; a posture detection means for detecting an angle of the hole contact unit with respect to a given reference; and a displacement detection part for detecting displacement or position of the probe. When the probe is brought into close contact with the inner surface of the hole to be measured, the angle of the hole contact unit is detected and the measured value of the inner diameter of the hole is obtained.

Description

Hole Measuring Device and Hole Measuring Method

[0001] The present invention relates to an automatic hole measuring device and an automatic hole measuring method that automatically perform hole measurement.

[0002] As a measuring instrument for measuring holes, for example, measuring the inner diameter of a hole, internal diameter measuring instruments such as Hall Test (registered trademark), cylinder gauge, and borematic (registered trademark) are used (see, for example, Patent Document 1). However, when using these internal diameter measuring instruments, operations such as advancing and retracting the measuring element and centering with the internal diameter measuring instrument inserted into the hole are required, which inevitably results in manual measurement by hand. Therefore, it has taken a lot of manpower and time to confirm the machining accuracy of holes with such internal diameter measuring instruments.

[0003] As an internal diameter measuring device for automating internal diameter measurement at the production site, it is conceivable to use a non-contact internal diameter measuring device. For example, it is conceivable to use air (patent document 2) or laser light (patent document 3). However, due to its mechanism, a non-contact measuring device is extremely expensive and also requires a lot of labor and cost for maintenance. Considering the measurement ability, the non-contact measuring device also has a point that it cannot reach the contact-type measuring instrument in terms of the stability of measurement accuracy. For example, due to its mechanism, there is a limit to the repeatability accuracy of an air micrometer, and the measurement range is extremely short (about several hundred micrometers). Also, when using laser light, it is greatly affected by the surface material and state of the measurement object.

[0004] It has also been proposed to automate hole measurement using a contact-type internal diameter measuring instrument (Patent Document 4). Assuming that centering cannot be performed without human hands, it is necessary to correct the measured value obtained in a state with a core deviation by a complex calculation. However, in this method, the measurement procedure and correction calculation based on correction are quite complex, and it is impossible to obtain a correct internal diameter measurement value anyway.

[0005] JP 2010-19783, JP 08-14871, JP 2016-80541, JP 2022-81675

[0006] There is a need for automated hole measuring devices and methods that are low-cost and easy to use, while achieving accuracy and stability comparable to human measurement. Furthermore, it is necessary to accurately inspect not only the internal diameter of a hole, but also its orientation (angle), which has rarely been measured until now. Given the increasing number of inspection items amidst labor shortages, there is a growing demand for automated measurement of not only the internal diameter but also the hole's orientation (angle).

[0007] A hole measuring device covering one side comprises a hole contact unit that drives a plurality of measuring probes to move forward and backward so that the plurality of measuring probes come into contact with the inner surface of a hole to be measured, and a posture detection means for detecting the angle of the hole contact unit with respect to a given reference, wherein the posture detection means detects the angle of the hole contact unit when the plurality of measuring probes are in close contact with the inner surface of the hole to be measured.

[0008] Furthermore, the hole measuring device relating to the other side comprises a hole contact unit that drives a plurality of measuring probes to move forward and backward so that the plurality of measuring probes come into contact with the inner surface of a hole to be measured; a displacement detection unit that detects the displacement or position of the measuring probes; and a moving means that moves the hole contact unit relative to the hole to be measured, wherein each of the measuring probes has an axial tip at its tip having a length parallel to the axis of the hole contact unit, and the moving means changes the relative position and orientation of the hole contact unit with respect to the hole to be measured as the hole contact unit moves the measuring probes forward and backward, and when the amount of protrusion of the measuring probes reaches its maximum, the inner diameter of the hole to be measured is determined based on the displacement or position of the measuring probes detected by the displacement detection unit.

[0009] This is an overall view of the automatic hole measuring device. This is a perspective view of the electric hole measuring unit from a slightly oblique angle in front. This is a side view of the electric hole measuring unit. This is a cross-sectional view illustrating the internal structure of the tip side of the electric internal diameter attitude measuring instrument. This is an example of the electric internal diameter attitude measuring instrument inserted into a hole. This is an example of the electric internal diameter attitude measuring instrument inserted into a hole. This is a diagram illustrating the operation of the electric internal diameter attitude measuring instrument inserted into a hole. This is a functional block diagram of the control unit. This is an overall flowchart of the automatic hole measuring operation. This is a flowchart illustrating the operation of the first adjustment process. This is a flowchart illustrating the operation of the first adjustment process. This is an example of the electric internal diameter attitude measuring instrument being misaligned from the center of the hole. This is a diagram showing the relationship between the amount of misalignment (amount of deviation from the center line of the hole) and the error from the true value of the internal diameter measurement. This is an example of the state in which the axis Ac of the electric internal diameter attitude measuring instrument is angularly misaligned with respect to the center line Lc of the hole. This is a diagram showing the relationship between the amount of angular misalignment (angle of inclination from the center line of the hole) and the error from the true value of the internal diameter measurement. This is a flowchart illustrating the operation of the second adjustment process. This is a diagram illustrating an example of a search parameter table. This is a flowchart illustrating the operation of the search adjustment process by translation. This is a diagram illustrating an example of the internal diameter measurement obtained in the search adjustment process. This is a diagram illustrating an example of the internal diameter measurement obtained in the search adjustment process. This is a flowchart illustrating the operation of the search adjustment process by rotation. This is a flowchart illustrating a modified version of the second adjustment process. This is a diagram illustrating an example of the use of an automatic hole measuring device.

[0010] Embodiments of the present invention will be illustrated and described with reference to the reference numerals assigned to each element in the figures. Note that individual embodiments may be implemented individually, or two or more embodiments may be combined, and examples of modifications provided in individual embodiments can be applied to other embodiments. (First Embodiment) The first embodiment of the present invention will be described. This embodiment is an automatic hole measuring device 1000 that automates the measurement of the inner diameter and angle of a hole.

[0011] (Automatic Hole Measuring Device 1000) Figure 1 is an overall view of the automatic hole measuring device 1000. The automatic hole measuring device 1000 comprises a measuring device main body 2000 and a control unit 3000 that controls the overall operation.

[0012] (Measuring device main body 2000) The measuring device main body 2000 comprises an electric hole measuring unit 2100 for measuring the target hole, and a multi-joint robot arm 2400 as a means of moving the electric hole measuring unit 2100.

[0013] (Electric hole measuring unit 2100) The electric hole measuring unit 2100 is attached to and held by the hand portion 2410, which is the tip of the robot arm portion 2400. The electric hole measuring unit 2100 is inserted into the inside of the hole to be measured to obtain the measurement of the inner diameter of the hole and the measurement of the angle of the hole.

[0014] The electric hole measuring unit 2100 of this embodiment has both the function of a hole diameter measuring device that obtains a measurement of the inner diameter of a hole, and the function of a hole attitude measuring device that obtains a measurement of the angle (attitude) of a hole. When only the inner diameter of the hole is to be obtained as a measurement, the inertial sensor unit 2270 as an attitude detection means is unnecessary. Also, when only the angle (attitude) of the hole is to be obtained as a measurement, a displacement sensor that detects the relative displacement of the rod 2220 (or measuring probe 2230) is necessary, but it is not necessary to precisely determine the amount of displacement (position) of the measuring probe from a precisely calibrated origin (base point). Modifications of these will be described later.

[0015] The configuration of the electric hole measuring unit 2100 will be explained. Figure 2 is an external perspective view of the electric hole measuring unit 2100, taken from a slightly oblique front angle. Figure 3 is a side view of the electric hole measuring unit 2100.

[0016] The electric hole measuring unit 2100 comprises an electric internal diameter posture measuring device 2200, a support frame section 2300, and a force sensor section 2330.

[0017] (Electric internal diameter attitude measuring device 2200) The electric internal diameter attitude measuring device 2200 basically motorizes the rod feed of an existing manual internal diameter measuring device (e.g., Hole Test, HOLTEST®) and further incorporates an inertial sensor unit 2270 as a means of attitude detection.

[0018] Figure 4 is a cross-sectional view illustrating the internal structure of the tip end of the electric internal diameter attitude measuring device 2200.

[0019] The electric internal diameter attitude measuring device 2200 comprises a cylindrical case portion 2210, a rod 2220, a measuring probe 2230, a thimble portion 2240, a displacement sensor portion 2250, an electric drive portion (automatic operation portion) 2260, and an inertial sensor portion (attitude detection means) 2270.

[0020] The cylindrical case portion 2210 is a cylindrical case as a whole. The rod 2220 moves axially inside the cylindrical case portion 2210. The cylindrical case portion 2210 has a main cylindrical portion 2211 and a head cylindrical portion 2212.

[0021] The main cylindrical portion 2211 houses almost the entire rod 2220. A female thread (not shown) is cut into a part of the inner circumference of the main cylindrical portion 2211. This female thread engages with the feed screw of the rod 2220 and constitutes a feed mechanism that moves the rod 2220 axially as the rod 2220 rotates.

[0022] Furthermore, a displacement sensor unit 2250 for detecting the movement (displacement or position) of the rod 2220 is housed inside the main cylindrical section 2211.

[0023] The head cylinder portion 2212 is connected to the tip side of the main cylinder portion 2211, and the head cylinder portion 2212 constitutes the measuring head portion. In this embodiment, the side of the cylinder case portion 2210 on which the head cylinder portion 2212 is provided is considered the tip side.

[0024] The rod 2220 is, as a whole, a long, rod-shaped body. The rod 2220 has a main rod 2221 and a tip rod 2222. The main rod 2221 is a spindle and has a male threaded feed screw (not shown) on the outer surface of its base end side (upper side in this embodiment). The female thread of the main cylindrical portion 2211 and the feed screw of the main rod 2221 are screwed together to form a feed mechanism.

[0025] The tip rod 2222 is located inside the head cylinder portion 2212. The base end (in this case, the upper end face) of the tip rod 2222 abuts against the tip (in this case, the lower end face) of the main rod 2221. The tip side (in this case, the lower side) of the tip rod 2222 is conical in shape.

[0026] The measuring probes 2230 are positioned in the head cylinder portion 2212 so as to move back and forth in a direction perpendicular (intersecting) to the axial direction of the rod 2220. Three measuring probes 2230 are arranged in the head cylinder portion 2212 at 120° intervals. Each measuring probe 2230 has a thin, round shaft tip 2231 made of carbide at its outer end. Each round shaft tip 2231 has a certain length in a direction parallel to the axis of the cylinder case portion 2210. When each measuring probe 2230 moves forward in the protruding direction, the round shaft tip 2231 comes into contact with the inner wall of the object to be measured.

[0027] Because the round-shaft tip 2231 has a certain length in a direction parallel to the axis of the cylindrical case portion 2210, a significant difference in the displacement of the measuring probe 2230 occurs when the axis of the cylindrical case portion 2210 coincides with the center line of the hole to be measured, compared to when there is even a slight misalignment. Conversely, this difference in the displacement of the measuring probe 2230 can serve as a sensitive indicator for detecting the misalignment between the axis of the cylindrical case portion 2210 (electric internal diameter attitude measuring device) and the center line of the hole to be measured. This point will be explained later in the operation description.

[0028] Each measuring probe 2230 has a tapered surface on its inner end, which contacts the conical surface of the tip rod 2222. The conical surface of the tip rod 2222 and the tapered surface of the measuring probe 2230 form a displacement direction conversion means that changes the direction of force and displacement at a right angle.

[0029] Inside the head cylinder 2212, there are springs (e.g., leaf springs) 2232 corresponding to each measuring probe 2230. One end of each leaf spring 2232 is fixed to the inner wall of the head cylinder 2212, and the other end of each leaf spring 2232 is fixed to each measuring probe 2230. The leaf springs 2232 bias each measuring probe 2230 in the direction of retraction into the head cylinder 2212. When the rod 2220 is moved (pulled up) towards its base end by an external force, the force of the leaf springs 2232 causes the measuring probe 2230 to move (retract) in the direction of entering the head cylinder 2212, following the rod 2220.

[0030] The part of the head cylinder 2212 from which the measuring probe 2230 extends and retracts (the tip of the internal diameter measuring instrument) is sometimes referred to as the measuring head.

[0031] The thimble portion 2240 is fitted onto the base end of the rod 2220 (main rod 2221) via a ratchet mechanism (not shown), and when the thimble portion 2240 is rotated by an external force, the rod 2220 (main rod 2221) rotates together with the thimble portion 2240.

[0032] A ratchet mechanism (not shown) is provided between the thimble portion 2240 and the base end of the rod 2220 (main rod 2221). The rotation direction of the thimble portion 2240 or the main rod 2221 in the direction that moves the main rod 2221 downward (the direction that extends the measuring probe 2230) is considered the positive rotation direction. Conversely, the rotation direction of the thimble portion 2240 or the main rod 2221 in the direction that moves the rod 2220 upward (the direction in which the measuring probe 2230 is retracted) is considered the negative rotation direction. The ratchet mechanism allows the thimble portion 2240 to rotate freely relative to the main rod 2221 during positive rotation, but does not allow free rotation during negative rotation.

[0033] There is an upper limit to the force (forward rotational force) transmitted from the thimble portion 2240 to the main rod 2221 via the ratchet mechanism. For example, the ratchet mechanism may be equipped with a spring (load-regulating elastic body) that restricts the upper limit of the (forward rotation) load applied from the thimble portion 2240 to the main rod 2221. If an attempt is made to rotate the main rod 2221 (forward) beyond the aforementioned load limit, the ratchet mechanism causes the thimble portion 2240 to rotate freely relative to the main rod 2221. This ratchet mechanism constitutes a constant pressure mechanism that restricts the upper limit of the force (measuring force) acting between the object to be measured and the measuring probe 2230. Conversely, a predetermined force (measuring force) is generated between the workpiece (object to be measured) and the measuring probe 2230, as defined by the ratchet mechanism. When the measuring probe 2230 applies this predetermined force (measuring force) to the workpiece, the reaction force is applied to the side of the measuring probe 2230, that is, to the side of the electric internal diameter posture measuring device 2200.

[0034] The displacement sensor unit 2250 is provided inside the main body cylindrical portion 2211 to detect the displacement of the main body rod 2221. The displacement sensor unit 2250 is, for example, a rotary encoder or a linear encoder, and the detection method is not particularly limited; for example, photoelectric encoders, capacitive encoders, electromagnetic induction encoders, and magnetic encoders can be used. The displacement (position) of the measuring probe 2230 is determined from the displacement (position) of the main body rod 2221 detected by the displacement sensor unit 2250.

[0035] The electric drive unit 2260 is a drive unit that rotates the thimble unit 2240. The electric drive unit 2260 is located above the thimble unit 2240. The electric drive unit 2260 is, for example, a motor, and the rotational output of the motor is transmitted to the thimble unit 2240 via a power transmission mechanism (such as a gear train, connecting belt, connecting shaft, or connecting link).

[0036] As the rod 2220 moves forward and backward using electric power, the measuring probe 2230 moves forward and backward in the direction of extending and retracting from the head cylinder portion 2212 in accordance with the movement of the rod 2220. By detecting the displacement (position) of the rod 2220 when the three measuring probes 2230 are in equal contact with the inner wall of the hole to be measured, the diameter of the hole to be measured is obtained as a measured value.

[0037] The inertial sensor unit 2270 may be mounted and assembled together with other electronic components inside the housing of the electric internal diameter attitude measuring device 2200 (for example, inside the cylindrical case portion 2210). Alternatively, the inertial sensor unit 2270 may be attached to the outer surface of the housing of the electric internal diameter attitude measuring device 2200 (for example, the outer surface of the cylindrical case portion 2210). Inertial sensors themselves are well known; for example, a 6-axis inertial sensor (3-axis gyroscope + 3-axis accelerometer) integrated onto a single chip is known.

[0038] In this embodiment, since we want to detect the angle (attitude) of the electric internal diameter attitude measuring device 2200 (more specifically, the axis of the cylindrical case portion 2210), to put it simply, a 3-axis gyro sensor would suffice. Of course, using a 6-axis inertial sensor would be even better, but this depends on the cost of the components.

[0039] Here, the angle (or attitude) of the electric internal diameter attitude measuring device 2200 (axis of the cylindrical case portion 2210) refers to the angle that the electric internal diameter attitude measuring device 2200 (axis of the cylindrical case portion 2210) makes with respect to a given reference. For example, the vertical line may be defined as the Z direction, and the two axes perpendicular to the vertical line (Z) direction may be defined as the X and Y axes. The angle (or attitude) of the electric internal diameter attitude measuring device 2200 (axis of the cylindrical case portion 2210) may be expressed by the angle from the Z axis and the angle from the X axis, or it may be expressed by the direction cosine. Alternatively, the inertial sensor portion 2270 (attitude detection means) may be calibrated so that a predetermined face or edge of the object to be measured (workpiece) is used as the reference (datum). If the center line of the electric internal diameter attitude measuring device 2200 (the axis of the cylindrical case portion 2210) coincides with the center line of the hole at the measurement point of the hole to be measured, then the angle (or attitude) of the electric internal diameter attitude measuring device 2200 (axis of the cylindrical case portion 2210) is the same as the angle (or attitude) of the hole to be measured.

[0040] For illustrative purposes, the center line of the electric internal diameter attitude measuring instrument 2200 (the axis of the cylindrical case portion 2210) is defined as the measuring instrument central axis Ac. The point at which the measuring instrument central axis intersects the lower end surface (tip surface) of the head cylindrical portion 2212 is defined as the measuring instrument base point Op. Figure 3 illustrates the measuring instrument central axis Ac and the measuring instrument base point Op.

[0041] Furthermore, the tool coordinate system (Xt, Yt, Zt) for the 2200 electric internal diameter attitude measuring instrument, which is used as a tool, is set. The measuring instrument base point Op is set as the origin of the tool coordinate system, and the Zt axis is set along the measuring instrument's central axis Ac. Then, the Xt and Yt axes are set to be perpendicular to the Zt axis (i.e., the measuring instrument's central axis Ac). For the sake of explanation, the rotation direction around the Xt axis is denoted as Rxt, and the rotation direction around the Yt axis is denoted as Ryt.

[0042] (Support frame section 2300) The support frame section 2300 includes a measuring instrument support frame section 2310 and a motor support frame section 2320. The measuring instrument support frame section 2310 supports the electric internal diameter attitude measuring instrument 2200 and connects the electric internal diameter attitude measuring instrument 2200 to the robot arm section 2400. The measuring instrument support frame section 2310 is an L-shaped member when viewed from the side and has a support column plate 2311 and a support base plate 2312.

[0043] The support strut plate 2311 is parallel and adjacent to the electric inside diameter measuring instrument 2200. The support pedestal plate 2312 is provided so as to be bent in an L shape from the lower end of the support strut plate 2311 toward the side of the electric inside diameter measuring instrument 2200. The support pedestal plate 2312 has a notch for inserting the cylinder case portion 2210 of the electric inside diameter measuring instrument 2200. In a state where the cylinder case portion 2210 passes through the notch, the middle stage of the cylinder case portion 2210 is placed on the support pedestal plate 2312, and the electric inside diameter measuring instrument 2200 is attached to the measuring instrument support frame portion 2310.

[0044] The motor support frame portion 2320 constitutes side walls that are stacked so as to surround the electric inside diameter posture measuring instrument 2200 on the support pedestal plate 2312, and supports the motor of the electric drive portion 2260 at the upper end of the motor support frame portion 2320.

[0045] (Force sensor portion 2330) The force sensor portion 2330 is, for example, a six-axis (forces in three orthogonal axial directions and rotational forces around the axes) force sensor. The force sensor portion 2330 detects the force applied to the electric inside diameter measuring instrument 2200 in all directions. The force sensor portion 2330 is interposed and arranged between the support frame portion 2300 and the robot arm portion 2400.

[0046] The articulated robot arm portion 2400 is a so-called robot arm portion 2400, and moves the hand portion 2410, which is the tip of the robot arm portion 2400, three-dimensionally with a rotational drive axis in the vertical direction and a rotational drive axis in the horizontal direction. The hand portion 2410 of the robot arm portion 2400 is connected to the support frame portion 2300 via the force sensor portion 2330.

[0047] (Control Unit 3000) Figure 8 is a functional block diagram of the control unit 3000. The control unit 3000 is composed of hardware or software incorporated in a computer (a so-called computer terminal having a CPU (Central Processing Unit), a ROM storing a predetermined program, and a RAM). The control unit 3000 is communicatively connected to the measuring device main body 2000 (the electric hole measuring unit 2100 and the robot arm unit 2400) by wire or wirelessly, and controls the operation of the measuring device main body 2000 (the electric hole measuring unit 2100 and the robot arm unit 2400). An operation control program (measurement part program) is installed in the computer terminal, and the control of the measurement operation is realized by the execution of the program. The method of supplying the program is not limited. The program recorded on a (non-volatile) recording medium may be directly inserted into the computer to install the program, or a reading device for reading the information of the recording medium may be externally attached to the computer, and the program may be installed from this reading device into the computer. It may also be supplied to the computer by a communication line such as the Internet, a LAN cable, a telephone line, or wirelessly.

[0048] The control unit 3000 includes a measurement operation control unit 3100, a robot arm drive control unit 3200, and a central control unit 3300.

[0049] The measurement operation control unit 3100 controls the operation of the electric hole measuring unit 2100. The measurement operation control unit 3100 includes a motor drive control unit 3110 and a sensor value acquisition unit 3120.

[0050] The motor drive control unit 3110 controls the drive of the electric drive unit 2260. The sensor value acquisition unit 3120 acquires sensor values from each sensor included in the electric hole measuring unit 2100. That is, the force detection value acquisition unit 3121 acquires a force detection value (6-axis (forces in three orthogonal axis directions and rotational forces around the axes)) from the force sensor unit 2330. The displacement sensor value acquisition unit 3122 receives the sensor value of the displacement sensor unit 2250 and obtains a measurement value of the inner diameter of the measurement target hole from the displacement (position) of the rod 2220. The angle sensor value acquisition unit 3123 acquires the sensor value of the inertial sensor unit 2270 and obtains a measurement value of the angle (attitude) of the electric inner diameter posture measuring device 2200.

[0051] The robot arm drive control unit 3200 controls the movement of the robot arm unit 2400.

[0052] The central control unit 3300 integrally controls the measurement motion control unit 3100 and the robot arm drive control unit 3200.

[0053] (Control operation of automatic hole measurement) This section describes the operation in which the main body of the measuring device 2000 (electric hole measuring unit 2100, robot arm unit 2400) automatically measures the inner diameter and angle of the hole to be measured under control by the control unit 3000.

[0054] Figure 9 is an overall flowchart of the automatic hole measurement operation. A workpiece W (object to be measured) having a hole to be measured (hole to be measured) is transported by a conveyor belt or rail on the manufacturing line and brought to a predetermined position in front of the measuring device main unit 2000 (electric hole measurement unit 2100, robot arm unit 2400). The automatic hole measuring device 1000 automatically performs hole measurements sequentially on the holes to be measured that have been designated (set) as the target of measurement among the transported workpiece W (object to be measured). The position (coordinates) and direction (orientation of the hole) of the hole to be measured are set (stored) as part of the measurement part program in the central control unit 3300. Alternatively, the hole to be measured may be searched for using image recognition such as a camera, and hole measurements (internal diameter measurement, angle measurement) may be performed sequentially and automatically.

[0055] The automatic hole measurement operation comprises a hole insertion process (approach process) (ST100), a first adjustment process (ST200), a second adjustment process (ST300), and a measurement value acquisition process (ST400).

[0056] In the hole insertion process (ST100), the robot arm 2400 moves the electric internal diameter attitude measuring device 2200, and the measuring head of the electric internal diameter attitude measuring device 2200 is inserted into the hole to be measured. See also Figure 4. When the electric internal diameter attitude measuring device 2200 reaches the target position, the robot arm 2400 is temporarily stopped.

[0057] If the position, size, and angle of the hole to be measured were machined without any error from the design values, and furthermore, if there were no error in the control operation of the robot arm 2400, then the measuring head of the electric internal diameter posture measuring instrument 2200 would be inserted into the true center of the hole to be measured, and furthermore, the axis of the electric internal diameter posture measuring instrument 2200 and the center line of the hole to be measured would perfectly coincide. If the axis of the electric internal diameter posture measuring instrument 2200 (measuring instrument central axis Ac) and the center line Lc of the hole to be measured would perfectly coincide, then the electric internal diameter posture measuring instrument 2200 could remain in the same position and posture (angle), and the measuring probe 2230 could simply be advanced to bring the measuring probe 2230 (round shaft tip 2231) into close contact with the inner wall of the hole. This would provide the correct internal diameter measurement and hole angle. However, in reality, there are errors from the design values ​​in the position, size, and angle of the hole to be measured, and there are also errors in the control operation of the robot arm 2400. Instead of manual adjustment, the automatic hole measuring device 1000 automatically adjusts itself to align the axis of the electric internal diameter posture measuring device 2200 (measuring device central axis Ac) with the center line Lc of the hole to be measured, thereby obtaining the correct internal diameter measurement value and hole angle.

[0058] The first adjustment step (ST200) is described below. The first adjustment step (ST200) adjusts the position and orientation of the electric internal diameter orientation measuring device 2200 based on the force applied to the electric internal diameter orientation measuring device 2200 from the inner wall of the hole when the measuring probe 2230 is advanced. In other words, the first adjustment step (ST200) is an adjustment step based on force sensing.

[0059] Figures 10 and 11 are flowcharts illustrating the operation of the first adjustment process (ST200). In the first adjustment process (ST200), first, in ST210, the sensor value (force detection value) currently detected by the force sensor unit 2330 is acquired and set as the reference value. Even if the electric internal diameter attitude measuring device 2200 is not touching the inner wall of the hole, the force sensor unit 2330 senses force due to the weight and tilt of the electric internal diameter attitude measuring device 2200. After recording the current force detection value from the force sensor unit 2330 as the reference value in ST210, the electric drive unit 2260 (automatic operation unit) of the electric internal diameter attitude measuring device 2200 moves the measuring probe 2230 forward (ST220), and the robot arm unit 2400 moves or rotates the electric internal diameter attitude measuring device 2200 (position and attitude adjustment) (ST230) based on the force detection value, in parallel.

[0060] In ST220, the forward movement of the measuring probe 2230 is initiated (ST220). Specifically, the motor drive control unit 3110 sends a drive pulse to the electric drive unit 2260, which rotates the rod 2220 with the rotation of the motor and advances the rod 2220 with the screw feed. As a result, the measuring probe 2230 moves forward in a direction that protrudes from the measuring head. After initiating the forward movement of the measuring probe 2230 in ST220, the forward movement of the measuring probe 2230 (ST220) continues in ST221 until predetermined contact determination conditions are met. Here, the contact determination conditions include the cessation of changes in the displayed value, threshold determination of torque and motor current, threshold determination of the difference between the force detected value and the reference value, etc.

[0061] Meanwhile, the control of the robot arm 2400 based on the force sensing of ST230 loops back to ST230 until the contact detection is OK (ST221: YES) and the contact detection signal is output (ST231: YES). ST230 continuously acquires force detection values ​​from the force sensing sensor 2330 moment by moment, and drives and controls the robot arm 2400 so that the latest acquired force detection value approaches the reference value, thereby moving or rotating the electric internal diameter attitude measuring device 2200, held by the hand portion 2410 of the robot arm 2400, relative to the inner wall of the hole. As a result, the electric internal diameter attitude measuring device 2200 moves or rotates relative to the inner wall of the hole in a way that avoids applying a force that deviates from the reference value to the electric internal diameter attitude measuring device 2200. In other words, the robot arm 2400 moves or rotates the electric internal diameter attitude measuring device 2200 so that it is released from the wall of the hole. By continuing this process, the electric internal diameter position measuring device 2200 will gradually move closer to the center of the hole, and the axis of the measuring device should become closer to being parallel to the center line of the hole.

[0062] Refer to Figures 5, 6, and 7 to supplement the above operation. If the position of the electric internal diameter attitude measuring device 2200 is offset from the center of the hole, one of the three measuring probes 2230 will hit the inner wall of the hole first. When the measuring probe 2230 that hits the inner wall moves forward, as illustrated in Figure 5, for example, the measuring probe 2230 pushes against the inner wall of the hole, and a reaction force is applied to the electric internal diameter attitude measuring device 2200.

[0063] Even if the electric internal diameter attitude measuring device 2200 is positioned close to the center of the hole, if the axis Ac of the electric internal diameter attitude measuring device 2200 and the center line Lc of the hole do not coincide and there is an angle, the measuring probe 2230 (round shaft tip 2231) will make contact with the inner wall of the hole on one side. In this case, for example, as illustrated in Figure 6, a rotational force will be applied to the electric internal diameter attitude measuring device 2200 as a reaction force from the inner wall of the hole. (Figure 6 is a simplified diagram showing two measuring probes in contact with the inner wall of the hole for easier understanding.) Such a reaction force is detected as a force by the force sensor unit 2330.

[0064] Then, by comparing the previously set reference value with the force detected by the force sensor unit 2330, the reaction force (resultant force) acting on the electric inner diameter posture measuring device 2200 from the workpiece (inner wall of the hole) is determined, and the electric inner diameter posture measuring device 2200 is moved or rotated in a direction that reduces this reaction force (Figure 7). In other words, the robot arm drive control unit 3200 drives and controls the robot arm unit 2400 to change the position or posture of the electric inner diameter posture measuring device 2200 in the direction of the acquired force (reaction force). That is, the robot arm drive control unit 3200 drives and controls the robot arm unit 2400 so that the force detected value detected by the force sensor unit 2330 approaches the aforementioned reference value.

[0065] While the robot arm 2400 moves or rotates the electric internal diameter attitude measuring device 2200 based on the force detection value, the electric drive unit 2260 (automatic operation unit) of the electric internal diameter attitude measuring device 2200 continues to drive (ST220), and therefore the force that the measuring probe 2230 receives from the inner wall of the hole (i.e., the latest force detection value) continues to change. Due to the movement or rotation of the electric internal diameter attitude measuring device 2200 driven by the robot arm 2400 and the continued forward movement of the measuring probe 2230, the force detection value by the force sensor unit 2330 is constantly acquired moment by moment, and the operation of ST230 continues so that the latest force detection value approaches the reference value.

[0066] As ST220 and ST230 continue, the electric internal diameter attitude measuring device 2200 approaches the center of the hole, and at the same time, the axis of the electric internal diameter attitude measuring device 2200 approaches parallel to the center line of the hole. However, as the forward movement of the measuring probe 2230 continues and the amount of forward movement of the measuring probe 2230 increases, the measuring probe 2230 will come into contact with the inner wall of the hole.

[0067] As the measuring probes 2230 move forward, eventually all of them will hit the inner wall of the hole, satisfying the contact detection condition (ST221). For example, the measuring probes 2230 may stop moving and the displayed value may stop changing, or the torque may increase, or the motor current may increase. Alternatively, the forces acting on the three measuring probes 2230 from the inner wall of the hole may become balanced, and the difference between the force detected value and the reference value may fall below a threshold.

[0068] When the contact detection condition (ST221) is met, a contact detection signal is output (or a contact detection flag may be set), and because the contact detection signal has been output, the decision step of ST231 (ST231:YES) exits the loop of ST230, and the first adjustment step (ST200) is effectively completed. That is, the forward movement of the measuring probe 2230 is stopped, and the drive of the robot arm section 2240 is stopped (ST232). Then, the measuring probe 2230 is moved backward (ST233).

[0069] As described above, the first adjustment step (ST200) brings the electric internal diameter attitude measuring device 2200 closer to the center of the hole, and at the same time, the axis of the electric internal diameter attitude measuring device 2200 approaches parallel to the center line of the hole. However, it is difficult to align the central axis Ac of the electric internal diameter attitude measuring device 2200 with the center line Lc of the hole using only the first adjustment step (ST200) based on force detection by the simple force sensor unit 2330, and it is also difficult to accurately determine that the central axis Ac of the electric internal diameter attitude measuring device 2200 has aligned with the center line Lc of the hole. Therefore, once a certain degree of adjustment has been made in the first adjustment step (ST200), the process moves on to the second adjustment step (ST300). In the case of internal diameter measuring instruments (especially those with a round shaft tip 2231 at the tip of the measuring probe), misalignment is reflected in the misalignment of the internal diameter measurement (or the difference in the amount of movement of the measuring probe). In the case of robot control, it is thought that focusing on the magnitude of this misalignment (or the difference in the amount of movement of the measuring probe) and the direction in which the misalignment occurs will allow for adjustment (alignment) and ensure that the alignment converges correctly.

[0070] Before explaining the second adjustment process ST300, let's explain the relationship between misalignment and internal diameter measurement error. Here, misalignment refers to the discrepancy between the axis Ac of the electric internal diameter attitude measuring device 2200 and the center line Lc of the hole, and has two meanings: positional misalignment and angular misalignment. Positional misalignment means that the axis Ac of the electric internal diameter attitude measuring device 2200 has a translational positional misalignment with respect to the center line Lc of the hole. Angular misalignment means that the axis Ac of the electric internal diameter attitude measuring device 2200 has an angular misalignment with respect to the center line Lc of the hole. For example, consider the case where the electric internal diameter attitude measuring device 2200 is misaligned from the center of the hole, as shown in Figure 12. Figure 12 illustrates a case where the axis Ac of the electric internal diameter attitude measuring device 2200 and the center line Lc of the hole are parallel, but the axis Ac of the electric internal diameter attitude measuring device 2200 has a translational positional misalignment with respect to the center line Lc of the hole. Note that in Figure 12, for illustrative purposes and to make the diagram easier to understand, the translational positional deviation is exaggerated. (If the first adjustment process ST200 had been performed first, it can be expected that the axis Ac of the electric internal diameter attitude measuring device 2200 and the center line Lc of the hole would be adjusted to be quite close.)

[0071] Assuming that the translational misalignment occurs in the Xt direction of the tool coordinate system (Xt, Yt, Zt), the relationship between the misalignment amount ΔXt from the center line Lc of the hole and the error of the measured inner diameter from the true value is shown in Figure 13. Figure 13 is a graph plotting the relationship between the misalignment amount ΔXt from the center line Lc of the hole on the horizontal axis and the error of the measured inner diameter on the vertical axis. The measured inner diameter obtained during the inner diameter measurement operation when the translational misalignment ΔXt is zero is the true measured inner diameter of the hole. In Figure 13, the true measured inner diameter obtained during measurement is the maximum value when the translational misalignment ΔXt is zero (i.e., the protrusion amount of the measuring probe 2230 is maximum). As the misalignment ΔXt increases, the measured inner diameter becomes smaller and smaller from the true value. This trend is the same whether the misalignment ΔXt occurs in the positive Xt direction or in the negative Xt direction. In other words, as illustrated in Figure 13, the graph will be convex upwards.

[0072] Figures 12 and 13 illustrate the case where the misalignment occurs in the positive or negative Xt direction, but the trend is the same even when the misalignment occurs in the positive or negative Yt direction. Of course, even when the misalignment occurs in the Xt and Yt directions, the magnitude of the internal diameter measurement error relative to the amount of misalignment differs slightly, but the trend in the graph is the same, with the true internal diameter measurement value obtained during the internal diameter measurement operation when the misalignment is zero being the largest value, and the obtained internal diameter measurement value decreasing as the misalignment increases. In other words, when the electric internal diameter attitude measuring device 2200 is inserted into a hole and the electric internal diameter attitude measuring device 2200 is translated in the Xt-Yt plane, there are differences in the internal diameter measurement values ​​obtained at each location, and the closer the electric internal diameter attitude measuring device 2200 gets to the center of the hole, the larger the obtained internal diameter measurement value becomes.

[0073] The same applies to angular misalignment. Figure 14 illustrates a case where the base point Op of the electric internal diameter attitude measuring instrument 2200 lies on the center line Lc of the hole, but the axis Ac of the electric internal diameter attitude measuring instrument 2200 has an angular misalignment ΔRyt with respect to the center line Lc of the hole. (For the sake of explanation, the misalignment is exaggerated in the figure for clarity.) Assuming that the angular misalignment occurs in the Ryt direction, Figure 15 shows the relationship between the amount of angular misalignment ΔRyt from the center line Lc of the hole and the error from the true value of the measured internal diameter. This trend is the same as that of translational positional misalignment, and the true measured internal diameter obtained by the measurement is at its maximum value when the angular misalignment ΔRyt is zero (i.e., the protrusion amount of the measuring probe 2230 is at its maximum). Furthermore, as the angular misalignment ΔRyt increases, the measured internal diameter becomes smaller and smaller from the true value. In other words, it becomes a curved graph that is convex upwards. This graph shows the same trend whether the angular displacement occurs in the ΔRxt direction or in both ΔRyt and ΔRxt directions.

[0074] Even in the case of angular misalignment, the graph takes an upward-convex, mountain-shaped form, partly because the measuring probe 2230 of the electric internal diameter attitude measuring instrument 2200 in this embodiment has a round shaft tip 2231 at its tip. Even if the electric internal diameter attitude measuring instrument 2200 is close to the center of the hole, if the axes of the two are misaligned, the round shaft tip 2231 of the measuring probe 2230 will make uneven contact. Furthermore, because the tip of the measuring probe 2230 is not a point contact but a shaft tip with a length parallel to the axis, uneven contact occurs in multiple measuring probes 2230 according to the axial misalignment, creating a gap between the measuring probe 2230 (round shaft tip 2231) and the inner wall of the hole. As a result, the measuring probe 2230 does not open (does not move forward). Therefore, the measured internal diameter (or the amount of advancement / return of the measuring probe) becomes smaller and smaller as the angular misalignment increases, and conversely, the smaller the angular misalignment, the larger the measured internal diameter (or the amount of advancement / return of the measuring probe) becomes as it approaches the true measured internal diameter. This effect becomes more pronounced as the length of the round-shank tip 2231 increases.

[0075] Furthermore, even when both positional and angular misalignment occur together, the trend of the graph remains the same, resulting in an upward-convex, mountain-shaped graph. In other words, when both positional and angular misalignment occur together, for example, when the electric internal diameter attitude measuring device 2200 is translated within the Xt-Yt plane, although there are slight differences in the height and slope of the peaks in the graph, the acquired internal diameter measurement value increases as the electric internal diameter attitude measuring device 2200 approaches the center of the hole. Similarly, when both positional and angular misalignment occur together, for example, when the electric internal diameter attitude measuring device 2200 is rotated, although there are slight differences in the height and slope of the peaks in the graph, the acquired internal diameter measurement value increases as the angular misalignment between the axis Ac of the electric internal diameter attitude measuring device 2200 and the center line Lc of the hole decreases.

[0076] From this, we can see that, both in the relationship between positional misalignment and inner diameter measurement, and in the relationship between angular misalignment and inner diameter measurement, by searching for the peak of the graph, both positional misalignment and angular misalignment can be progressively reduced. Moreover, whether adjusting only the positional misalignment or only the angular misalignment, the same upward-convex trend appears between the amount of misalignment and the inner diameter measurement, so it can also be said that the positional misalignment and angular misalignment can be adjusted by changing them one by one in sequence.

[0077] The second adjustment step (ST300) will now be explained. The second adjustment step (ST300) involves advancing the measuring probe 2230 and adjusting the position and orientation of the electric internal diameter orientation measuring device 2200 based on the amount of displacement of the measuring probe 2230 when the measuring probe 2230 contacts the inner wall of the hole. In other words, the second adjustment step (ST300) is an adjustment step based on the amount of displacement of the measuring probe 2230.

[0078] Figure 16 is a flowchart illustrating the operation of the second adjustment process (ST300). The second adjustment process (ST300) consists of a translational search and adjustment process (ST320) and a rotational search and adjustment process (ST330). These two processes are repeated while changing the axis of translational movement and the axis of rotation. This adjusts the position and orientation of the electric internal diameter attitude measuring device 2200 so that more accurate internal diameter measurements and hole angles can be obtained for the hole to be measured.

[0079] Here, we pre-set the search parameters necessary for the iterative search. The necessary search parameters are, with "i" as the counter variable i, i = 0, 1, 2, 3, ..., the translational search range αi, the translational search pitch δi, the rotational search range βi, the rotational search pitch γi, and the number of iterations ni. For example, a table of the counter variable i and each parameter (αi, δi, βi, γi, ni) is set in advance, as illustrated in Figure 17. The key point is that the translational search range αi, translational search pitch δi, rotational search range βi, and rotational search pitch γi should be set so that they gradually decrease as the counter variable i increases. For example, for the translational search range αi, it is α0>α1>α2>..., and for the translational search pitch δi, it is δ0>δ1>δ2>... Similarly, the rotational search range βi is β0 > β1 > β2 > ..., and the rotational search pitch γi is γ0 > γ1 > γ2 > ....

[0080] The number of repetitions ni is, for example, "2 times," but it could also be "1 time," or it could increase or decrease during the process.

[0081] Returning to the flowchart in Figure 16, we first start with the counter variable i=0 and read out [translational search range α0, translational search pitch δ0, rotational search range β0, rotational search pitch γ0, and number of iterations n0] from the search parameter table (ST301). Then, as the initial combination of search directions, we set the translational search direction to the Xt direction and the rotational search direction to Ryt (ST310).

[0082] The translation-based search adjustment process (ST320) is shown in the flowchart of Figure 18. In ST321, the translation search range αi and translation search pitch δi, which were read earlier, are set as conditions for translational search. Here, since counter i=0, the translation search range α0=0.3mm and the translation search pitch δ0=0.15mm are assumed.

[0083] Next, translational movement and acquisition of displacement sensor values ​​are performed (ST322). Currently, the translational search direction is the Xt direction, the translational search range α0 = 0.3 mm, and the translational search pitch δ0 = 0.15 mm. This means that the electric internal diameter attitude measuring instrument 2200 is translated in the Xt direction with a search range of plus or minus 0.3 mm, in increments of a search pitch of 0.15 mm, and an internal diameter measurement is acquired each time the search pitch moves by 0.15 mm.

[0084] The order of measurement does not matter, but for example, as shown in Figure 19, first, the electric internal diameter attitude measuring device 2200 is moved -0.3 mm in the Xt direction. Then, the measuring probe 2230 is advanced and the ratchet mechanism (constant pressure mechanism) is activated to generate a predetermined measuring pressure, and the displacement of the measuring probe 2230, that is, the internal diameter measurement value, is obtained. The internal diameter measurement value obtained in this way is shown in Figure 19. <1> Let's assume we can plot it like this.

[0085] Furthermore, after performing adjustment processes (first adjustment process ST200, second adjustment process ST300) to minimize positional and angular deviations, the measurement values ​​(inner diameter measurement values) obtained in the final measurement value acquisition process (ST400) are the final determined measurement values ​​(inner diameter measurement values). Therefore, the displacement sensor values ​​obtained during the second adjustment process ST300 could perhaps be called provisional inner diameter measurement values, but since it is unlikely to cause any misunderstanding, the term "provisional" will be omitted.

[0086] The measuring probe 2230 is temporarily retracted, the electric internal diameter attitude measuring device 2200 is moved 0.15 mm in the Xt direction, and the ratchet mechanism (constant pressure mechanism) is also activated to obtain the internal diameter measurement value. <2> The inner diameter measurement is obtained by translating the device in 0.15 mm increments. <1> from <5> Let's assume we obtain this. Then, as explained earlier, the position where the largest inner diameter measurement was obtained should be close to the center of the hole. Therefore, in this case, the maximum value of the inner diameter measurement is <5> Identified as (ST323), this maximum value <5> The electric internal diameter attitude measuring device 2200 is moved to the acquired position, that is, to a position that has been translated by +0.3 mm in the Xt direction relative to the initial position (ST324).

[0087] In the previous example, the inner diameter measurement was <1> from <5> This was an example of monotonically increasing numbers in that order. (Of course, conversely, <5> It starts with, <4> , <3> If the measurements are obtained in this order, it can be said that the decrease is monotonically decreasing. This means that the positional displacement was relatively large, that is, the positional displacement was 0.3 mm or more.

[0088] If, hypothetically, the initial misalignment was relatively small, i.e., less than 0.3 mm, then the center of the hole would be within the 0.3 mm search range. In that case, as illustrated in Figure 20, a point of change can be seen where the inner diameter measurement changes from increasing to decreasing. Even in this case, the maximum value of the inner diameter measurement (in Figure 20) <4> ) identify (ST323), and this maximum value <4> The electric internal diameter attitude measuring device 2200 is moved to the acquired position, that is, to a position that has been translated by +0.15 mm in the Xt direction relative to the initial position (ST324).

[0089] In this way, the translational search and adjustment process ST320 has been completed once. Therefore, the process will now move on to the rotational search and adjustment process ST330.

[0090] Now that you understand the roles of the (translational) search range (αi) and (translational) search pitch (δi), let me add some details. The center of the hole (or the center line Lc of the hole) does not need to be within the initial search range (α0), but if you want to get as close to the center of the hole (or the center line Lc of the hole) as possible as quickly as possible (on the first or second pass), it is best to set the initial search range (α0) to be somewhat wide. If you divide the slightly wider search range into too many small increments, the number of internal diameter measurements will increase and it will take more time, so it is best to set the initial search pitch to be relatively large. On the other hand, since you ultimately want to pinpoint the center (center line of the hole) of the hole with extreme accuracy, it is best to fine-tune the search pitch to a specified level of precision in the end. The specified values ​​δf and γf for the final search pitch can be determined, for example, according to the required accuracy of the target diameter or angle to be measured. From this perspective, the translational search range αi, translational search pitch δi, rotational search range βi, and rotational search pitch γi are set to gradually decrease as the counter variable i increases.

[0091] The flowchart for the rotational search and adjustment process ST330 is shown in Figure 21. Up to this point, we have explained that the tendency for errors in the internal diameter measurement to appear is the same whether the error is due to translational positional deviation or rotational angular deviation. Therefore, if you replace translation with rotation in the flowchart of Figure 18, you will understand that it becomes the flowchart of Figure 21 (rotational search and adjustment process ST330). In this way, let's assume that the translational positional deviation in the Xt direction and the rotational angular deviation in the Ryt direction have each been adjusted once.

[0092] Returning to the flowchart in Figure 16, ST340 determines whether the number of iterations n0 (2 in this case) set in the search parameter table has been reached (ST340). Here, since ST320 (translational search in the Xt direction) and ST330 (rotational search in the Ryt direction) have only been performed once, ST320 (translational search in the Xt direction) and ST330 (rotational search in the Ryt direction) are repeated one more time.

[0093] It may seem like we are simply repeating the same process, but the second translational search in the Xt direction (ST320) is performed after the adjustments have already been made by the first translational search in the Xt direction (ST320) and the rotational search in the Ryt direction (ST330). In particular, since the angular deviation has been adjusted by the rotation in the Ryt direction, it can be expected that the translational position in the Xt direction will move much closer to the center of the hole in the second translational search in the Xt direction (ST320).

[0094] Once a predetermined number of iterations (in this case, n0=2) have been completed, the axis of the search direction is changed (ST350). That is, the translational search direction is changed from the Xt direction to the Yt direction, and the rotational search direction is changed from the Ryt direction to the Rxt direction. Then, the loop counter i is counted up (ST370), and the process returns to ST320, repeating the translational search with the search direction set to the Yt direction (ST320) and the rotational search with the search direction set to the Rxt direction (ST330) (ST340).

[0095] As the loop of the second adjustment step ST300 in Figure 16 is repeated, the base point Op of the electric internal diameter attitude measuring device 2200 approaches the center of the hole, and the axis Ac of the electric internal diameter attitude measuring device 2200 approaches (becomes parallel to or coincides with) the center line Lc of the hole. When the search pitch δi, γi reaches the specified fineness δf, γf (ST360: YES), it means that the center of the hole and the center line of the hole can be identified with this fineness. At this state, it is determined that the adjustment of the position and attitude of the electric internal diameter attitude measuring device 2200 is complete.

[0096] As a result, the electric internal diameter and orientation measuring device 2200 should have been able to adjust its position and orientation to be closer to the center line of the hole to be measured. Now, returning to Figure 9, the measurement value acquisition process (ST400) is performed. That is, the measurement values ​​of the internal diameter and angle (orientation) of the hole to be measured are obtained.

[0097] The motor drive control unit 3110 drives the electric drive unit 2260 with drive pulses, advancing the rod 2220 in a screw-like manner. The measuring probe 2230 moves forward, and at this time, all the round shaft tips 2231 of the measuring probe 2230 should simultaneously make contact with the inner wall of the hole without any gaps. The measuring probe 2230 is advanced until the ratchet mechanism is activated, ensuring that the predetermined measuring pressure is firmly applied. Then, the displacement of the rod 2220 is obtained from the displacement sensor unit 2250, and the angle sensor value is obtained from the inertia sensor unit 2270. As a result, the displacement of the rod 2220 is converted to the displacement of the measuring probe 2230, and an accurate measurement of the inner diameter of the hole to be measured is obtained. Along with this, the accurate angle (attitude or orientation) of the hole to be measured is also obtained as a measurement value.

[0098] The automated hole measurement operation can be performed unattended, so it is sufficient to measure the holes to be measured one after another according to the program. While the first adjustment process (force-based adjustment) ST200 may be possible to do manually, the second adjustment process (adjustment process based on the displacement of the measuring probe 2230) ST300 cannot be performed manually. For example, it is impossible for a person to slightly displace (fluctuate) the electric internal diameter posture measuring instrument 2200, rotate the thimble forward and backward many times, remember the slight difference in the measured display value and the position and posture at that time, and reproduce it exactly. This is an excellent automated hole measurement method that cleverly combines the characteristics of internal diameter measuring instruments (especially internal diameter measuring instruments with shaft tips on the measuring probes) and the characteristics of robot control.

[0099] (Modification 1) In the first embodiment, an inertial sensor unit 2270 incorporated into the electric internal diameter attitude measuring instrument 2200 was used as the attitude detection means. The attitude detection means does not have to be incorporated into the measuring instrument unit and tilt integrally, as in the electric internal diameter attitude measuring instrument 2200. Hereinafter, a measuring instrument unit that does not have an integrated attitude detection means, but can take an attitude that follows the hole (center line) when the round shaft tip of the measuring probe is brought into close contact with the inner wall of the hole, will be called a "hole contact unit".

[0100] As a means for detecting the orientation, for example, it may be a device that can remotely and non-contactually sense the angle (orientation) of the hole contact unit. For example, it may be a laser angle detector having a laser emitter and a light receiver, where the light receiver detects that the laser reflection angle differs depending on the angle (orientation) of the hole contact unit. Alternatively, the laser emitter may be attached to the hole contact unit, and the light receiver, which is separate from the hole contact unit, may detect that the laser emission direction differs depending on the angle of the hole contact unit. The angle of the hole contact unit may also be detected by image analysis from an image of the hole contact unit captured by a camera.

[0101] (Modification 2) Now, if we consider the hole contact unit described above and focus on it as a measuring instrument for measuring hole orientation, there is no need for high-precision internal diameter measurement (i.e., dimensional measurement). Therefore, it is sufficient to have a displacement sensor unit capable of performing the second adjustment process (adjustment process ST300 based on the amount of displacement). In other words, if the displacement sensor unit is configured with an encoder, it is sufficient to be able to compare the magnitudes of the displacement sensor values ​​without having to perform precise zero setting (base point setting or calibration). However, it is preferable for the detection resolution of the displacement sensor unit (encoder) to be high. The detection resolution of the displacement sensor unit (encoder) correlates with the accuracy of the second adjustment process (adjustment based on the amount of displacement of the measuring probe 2230). If the internal diameter measurement value is not acquired, and the instrument is specialized in measuring hole orientation by being able to compare the magnitudes of the displacement sensor values, it becomes a hole orientation measuring device and hole orientation measuring method.

[0102] (Modification 3) Alternatively, if attitude detection is not performed and the system is intended to be solely for measuring the inner diameter, then an attitude detection means such as an inertial sensor unit may be unnecessary. In this case, it becomes a so-called automatic inner diameter measuring device (hole diameter measuring device) and an automatic inner diameter measuring method (hole diameter measuring method).

[0103] (Modification 4) In the first embodiment, the first adjustment step (ST200) was a force-based adjustment step. This is expected to reduce the number of loops in the second adjustment step (displacement-based adjustment step ST300) and also improve the accuracy of the adjustment (centering). However, it is also possible to skip the first adjustment step (ST200) and not perform the first adjustment step (ST200). For example, the same effect can be obtained by making the (initial) translational search range αi and rotational search range βi in the second adjustment step (displacement-based adjustment step ST300) relatively large, or by increasing the number of loops. If the first adjustment step (ST200) is skipped, the force sensor unit as hardware does not need to be present. Alternatively, the robot arm unit 2400 may be equipped with a force sensor unit for control and collision detection, and the first adjustment step (ST200) may be skipped as the adjustment (centering) operation for the automatic hole measurement operation.

[0104] (Modification 5) The orientation (angle) of the hole can also be determined while changing the depth (measurement point) within the same hole. This makes it possible to measure the coaxiality of cylindrical (cylinder) or stepped holes. Until now, measuring the coaxiality of cylindrical holes (cylinders) was a difficult and time-consuming task, but according to the present invention, it can be performed automatically and unattended, making it a very significant contribution to industry.

[0105] (Modification 6) As a modification of the second adjustment step ST300, instead of pre-setting the number of repetitions ni, the search along the same axis may be repeated until a point of change (peak) is found where the internal diameter measurement changes from increasing to decreasing (ST321, ST331), as illustrated in the flowchart of Figure 22.

[0106] Note that in Figure 16 or Figure 22, the combinations and order of axes to be searched are not limited to the example combinations and order. In Figure 16 or Figure 22, the rotational search (ST330) may be performed before the translational search (ST320). Also, the axis combination may be searched using the combination of Xt and Yt, and then the axes may be changed to search using the combination of Ryt and Rxt.

[0107] (Supplement to Usage Example) As shown in Figure 1, the object to be measured (workpiece with holes) may be brought in front of the automatic hole measuring device 1000. Alternatively, if the automatic hole measuring device 1000 is installed next to the machining equipment as illustrated in Figure 23, inline measurement is also possible. For example, holes can be drilled in a workpiece using an NC lathe 4000, and the holes can be measured while the workpiece is still fixed in the chuck 4100, either during or after machining. In this case, as shown in Figure 23, the electric hole measuring unit 2100 can be inserted into the NC lathe 4000 by the robot arm (movement means) 2400, and the hole measurement of the workpiece (hole diameter, inclination of the hole axis, coaxiality of the hole, etc.) can be measured inline. In the first embodiment, there is no joint that allows relative movement, such as a floating joint, between the end effector (hand part 2410) of the robot arm 2400 and the electric hole measuring unit 2100, and the electric hole measuring unit 2100 is rigidly held by the robot arm 2400. Therefore, the electric hole measuring unit 2100 will not fall or tilt due to its own weight, whether it is oriented vertically or horizontally. Generally, lathe machining often involves drilling holes horizontally in the workpiece, and the fact that the electric hole measuring unit 2100 can be oriented horizontally is convenient for inline measurement. In addition, the ability to freely orient the electric hole measuring unit 2100 makes it easy to insert into narrow spaces.

[0108] As a means of movement, it is sufficient to be able to move the electric hole measuring unit 2100 (hole contact unit) relative to the hole to be measured. Therefore, instead of attaching the electric hole measuring unit 2100 (hole contact unit) to the robot arm (movement means) 2400, the electric hole measuring unit 2100 (hole contact unit) may be fixedly installed on a predetermined fixed stand or the like, and the object to be measured (hole to be measured) may be moved by the movement means (robot arm 2400, etc.). When the electric hole measuring unit 2100 (hole contact unit) is fixedly installed and the object to be measured (hole to be measured) is moved by the movement means (robot arm 2400, etc.), for example, a non-contact sensing posture detection means using a camera or laser may be employed to detect the posture (angle) of the electric hole measuring unit 2100 (hole contact unit) and the posture (angle) of a predetermined face or edge of the object to be measured (workpiece) as a given reference. Then, by evaluating the angle (tilt) that the electric hole measuring unit 2100 (hole contact unit) makes with respect to a reference, the angle of the hole to be measured can be determined. Of course, this is just an example, and the detection method of the posture detection means is not limited. The force sensor unit 2330 only needs to be able to detect the force applied to the electric internal diameter measuring instrument 2200, so the force sensor unit 2330 may be built into the electric internal diameter measuring instrument 2200 or placed between the electric internal diameter measuring instrument 2200 and a predetermined fixed stand so that the force sensor unit 2330 can directly detect the force applied to the electric internal diameter measuring instrument 2200. Alternatively, the force sensor unit may be provided on the moving means (such as the robot arm unit 2400) that moves the object to be measured (the hole to be measured), so that the force applied to the electric internal diameter measuring instrument 2200 can be detected indirectly (through the object to be measured).

[0109] It should be noted that the present invention is not limited to the embodiments described above, and can be modified as appropriate without departing from the spirit of the invention.

[0110] With regard to embodiments including the above examples, the following additional information is disclosed.

[0111] (Note 1) A hole measuring device comprising: a hole contact unit that drives a plurality of measuring probes to move forward and backward so that the plurality of measuring probes come into contact with the inner surface of a hole to be measured; and a posture detection means for detecting the angle of the hole contact unit with respect to a given reference, wherein the posture detection means detects the angle of the hole contact unit when the plurality of measuring probes are in close contact with the inner surface of the hole to be measured.

[0112] (Note 2) The hole measuring device described in Note 1, characterized in that it is provided with a moving means for moving the hole contact unit and the hole to be measured relative to each other.

[0113] (Note 3) The hole measuring device described in Note 2, wherein each of the measuring probes has an axial tip at its tip having a length parallel to the axis of the hole contact unit, and the moving means changes the relative position and relative orientation of the hole contact unit with respect to the hole to be measured, causing the hole contact unit to move the measuring probe forward and backward, and when the amount of protrusion of the measuring probe is maximized, the orientation detection means determines the angle of the hole contact unit detected as the angle of the hole to be measured.

[0114] (Note 4) A hole measuring device that automatically measures the angle of a hole to be measured, comprising: a hole contact unit that drives a plurality of measuring probes to move forward and backward so that the plurality of measuring probes come into contact with the inner surface of a hole to be measured; a posture detection means for detecting the angle of the hole contact unit with respect to a given reference; and a moving means for moving the hole contact unit and the hole to be measured relative to each other, wherein each of the measuring probes has an axial tip at its tip having a length parallel to the axis of the hole contact unit, wherein the moving means changes the relative position and relative posture of the hole contact unit with respect to the hole to be measured, causing the hole contact unit to move the measuring probes forward and backward, and when the amount of protrusion of the measuring probes reaches its maximum, the posture detection means determines the angle of the hole contact unit detected as the angle of the hole to be measured.

[0115] (Note 5) A hole orientation measurement method described in Note 4, characterized in that the coaxiality of the hole to be measured is measured by determining the angle of the hole to be measured at different depths.

[0116] (Note 6) A hole measuring device comprising: a hole contact unit that drives a plurality of measuring probes to move forward and backward so that the plurality of measuring probes come into contact with the inner surface of a hole to be measured; a displacement detection unit that detects the displacement or position of the measuring probes; and a moving means that moves the hole contact unit relative to the hole to be measured, wherein each of the measuring probes has an axial tip at its tip having a length parallel to the axis of the hole contact unit; and the moving means changes the relative position and orientation of the hole contact unit with respect to the hole to be measured as the hole contact unit moves the measuring probes forward and backward, and when the amount of protrusion of the measuring probes reaches its maximum, the inner diameter of the hole to be measured is determined based on the displacement or position of the measuring probes detected by the displacement detection unit.

[0117] (Note 7) A hole measuring device for automatically measuring the inner diameter of a hole to be measured, comprising: a hole contact unit that drives a plurality of measuring probes to move forward and backward so that the plurality of measuring probes come into contact with the inner surface of a hole to be measured; a displacement detection unit that detects the displacement or position of the measuring probes; and a moving means that moves the hole contact unit relative to the hole to be measured, wherein each of the measuring probes has an axial tip at its tip having a length parallel to the axis of the hole contact unit, wherein the moving means changes the relative position and relative orientation of the hole contact unit with respect to the hole to be measured, causing the hole contact unit to move the measuring probes forward and backward, and when the amount of protrusion of the measuring probes reaches its maximum, the inner diameter of the hole to be measured is determined based on the displacement or position of the measuring probes detected by the displacement detection unit.

[0118] (Appendix 8) A hole measuring device according to any one of Appendix 2, Appendix 3, and Appendix 6, wherein the device is equipped with a force sensor unit for detecting the force applied to the hole contact unit, and when the hole contact unit drives the measuring probe forward and backward while the moving means changes the relative position and relative orientation of the hole contact unit with respect to the hole to be measured, the moving means changes the relative position and relative orientation of the hole contact unit so that the hole contact unit is aligned with the center line of the hole to be measured, based on the direction and magnitude of the force detected by the force sensor unit.

[0119] (Note 9) A hole measurement method according to any one of Notes 4, 5, and 7, wherein the hole measurement device includes a force sensor unit that detects the force applied to the hole contact unit, and when the moving means changes the relative position and relative orientation of the hole contact unit with respect to the hole to be measured, the moving means changes the relative position and relative orientation of the hole contact unit so that the hole contact unit is aligned with the center line of the hole to be measured, based on the direction and magnitude of the force detected by the force sensor unit.

[0120] 1000 Automatic hole measuring device 2000 Measuring device main body 2100 Electric hole measuring unit 2200 Electric inner diameter posture measuring device 2210 Cylinder case 2211 Main cylinder 2212 Head cylinder 2220 Rod 2220 Measuring head 2221 Main rod 2222 Tip rod 2230 Measuring probe 2231 Round shaft tip 2232 Leaf spring 2240 Thimble 2250 Displacement sensor 2260 Electric drive unit (automatic operation unit) 2270 Inertial sensor unit (posture detection means) 2300 Support frame 2310 Measuring device support frame 2311 Support column plate 2312 Support base plate 2320 Motor support frame 2330 Force sensor unit 2400 Robot arm 2410 Hand unit 3000 Control unit 3100 Measurement and motion control unit 3110 Motor drive control unit 3120 Sensor value acquisition unit 3121 Force detection value acquisition unit 3122 Displacement sensor value acquisition unit 3123 Angle sensor value acquisition unit 3200 Robot arm drive control unit 3300 Central control unit

Claims

1. A hole measuring device comprising: a hole contact unit that drives a plurality of measuring probes to move forward and backward so that the plurality of measuring probes come into contact with the inner surface of a hole to be measured; and a posture detection means for detecting the angle of the hole contact unit with respect to a given reference, wherein the posture detection means detects the angle of the hole contact unit when the plurality of measuring probes are in close contact with the inner surface of the hole to be measured.

2. A hole measuring device according to claim 1, characterized in that it comprises a moving means for moving the hole contact unit and the hole to be measured relative to each other.

3. A hole measuring device according to claim 2, wherein each of the measuring probes has an axial tip at its tip having a length parallel to the axis of the hole contact unit, and the moving means changes the relative position and relative orientation of the hole contact unit with respect to the hole to be measured, causing the hole contact unit to move the measuring probe forward and backward, and when the amount of protrusion of the measuring probe is maximized, the orientation detection means determines the angle of the hole contact unit detected as the angle of the hole to be measured.

4. A hole measuring device that automatically measures the angle of a hole to be measured, comprising: a hole contact unit that drives a plurality of measuring probes to move forward and backward so that the plurality of measuring probes come into contact with the inner surface of a hole to be measured; a posture detection means for detecting the angle of the hole contact unit with respect to a given reference; and a moving means for moving the hole contact unit and the hole to be measured relative to each other, wherein each of the measuring probes has an axial tip at its tip having a length parallel to the axis of the hole contact unit, wherein the moving means changes the relative position and relative posture of the hole contact unit with respect to the hole to be measured, causing the hole contact unit to move the measuring probes forward and backward, and when the amount of protrusion of the measuring probes is maximized, the posture detection means determines the angle of the hole contact unit detected as the angle of the hole to be measured.

5. A hole orientation measurement method according to claim 4, characterized in that the coaxiality of the hole to be measured is measured by determining the angle of the hole to be measured at different depths.

6. A hole measuring device comprising: a hole contact unit that drives a plurality of measuring probes to move forward and backward so that the plurality of measuring probes come into contact with the inner surface of a hole to be measured; a displacement detection unit that detects the displacement or position of the measuring probes; and a moving means that moves the hole contact unit relative to the hole to be measured, wherein each of the measuring probes has an axial tip at its tip having a length parallel to the axis of the hole contact unit; and the moving means changes the relative position and orientation of the hole contact unit with respect to the hole to be measured as the hole contact unit moves the measuring probes forward and backward, and when the amount of protrusion of the measuring probes reaches its maximum, the inner diameter of the hole to be measured is determined based on the displacement or position of the measuring probes detected by the displacement detection unit.

7. A hole measuring device for automatically measuring the inner diameter of a hole to be measured, comprising: a hole contact unit that drives a plurality of measuring probes to move forward and backward so that the plurality of measuring probes come into contact with the inner surface of a hole to be measured; a displacement detection unit that detects the displacement or position of the measuring probes; and a moving means that moves the hole contact unit relative to the hole to be measured, wherein each of the measuring probes has an axial tip at its tip having a length parallel to the axis of the hole contact unit, the method being characterized in that the moving means changes the relative position and orientation of the hole contact unit with respect to the hole to be measured, causing the hole contact unit to move the measuring probes forward and backward, and when the amount of protrusion of the measuring probes reaches its maximum, the inner diameter of the hole to be measured is determined based on the displacement or position of the measuring probes detected by the displacement detection unit.

8. A hole measuring device according to any one of claims 2, 3, and 6, comprising a force sensor unit for detecting a force applied to the hole contact unit, wherein when the moving means changes the relative position and relative orientation of the hole contact unit with respect to the hole to be measured, and the hole contact unit drives the measuring probe forward and backward, the moving means changes the relative position and relative orientation of the hole contact unit so that the hole contact unit is aligned with the center line of the hole to be measured, based on the direction and magnitude of the force detected by the force sensor unit.

9. A hole measurement method according to any one of claims 4, 5, and 7, wherein the hole measurement device comprises a force sensor unit for detecting a force applied to the hole contact unit, and when the moving means changes the relative position and relative orientation of the hole contact unit with respect to the hole to be measured, the moving means changes the relative position and relative orientation of the hole contact unit so that the hole contact unit is aligned with the center line of the hole to be measured, based on the direction and magnitude of the force detected by the force sensor unit.

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