Automatic measurement system and control method for automatic measurement system

Abstract

The present invention provides an automatic measurement system that detects a hazardous condition before a measurement sensor tool comes into contact with an object during execution of automatic measurement, and reliably avoids unintended collision of the measurement sensor tool with the object. The automatic measurement system comprises a measurement sensor tool for measuring dimensions or shape of an object to be measured, and a moving mechanism that moves the measurement sensor tool with respect to the object to be measured. Furthermore, the automatic measurement system comprises: a safety monitoring sensor provided so as to detect a space including the measurement sensor tool itself and an area in a vicinity of the measurement sensor tool; and a safety monitoring determination unit that monitors whether or not an object is present within a preset safe distance d from an outer surface of the measurement sensor tool in a space in a vicinity of the measurement sensor tool.

Description

Automatic Measurement System and Control Method for Automatic Measurement System

[0001] The present invention relates to an automatic measurement system and a control method for an automatic measurement system.

[0002] As measuring instruments for measuring the dimensions and shapes of measurement objects, there are internal diameter measuring instruments such as Hall tests, cylinder gauges, and borematics (registered trademark) (for example, see Patent Document 1). Such small-sized dimension and shape measuring instruments are premised on manual measurement operations. However, due to the current labor shortage problem and the further improvement of measurement efficiency, there is a demand to fully automate the measurement of dimensions or shapes that were previously manually operated. Therefore, the applicant of the present application has proposed an automatic internal diameter measurement system in which an electrically driven internal diameter measuring instrument is attached to the tip of a multi-joint robot arm and the measurement target locations are automatically measured sequentially, as in Patent Document 2 and Patent Document 3 for example.

[0003] JP-A-2010-019783 JP-A-2021-009115 JP-A-2023-142301

[0004] In order to measure the diameter (dimension) of a hole with an electric internal diameter measuring instrument, the electric internal diameter measuring instrument must be inserted into the hole to be measured by moving the tip of the multi-joint robot arm section. Here, if the measurement object is not processed as designed or an error occurs in the drive control of the robot arm section, the measurement head section of the electric internal diameter measuring instrument may not enter the hole as planned, and there is a possibility that the measurement head section and the measurement object will collide. If a precision measuring instrument such as an internal diameter measuring instrument collides with an unintended object unintentionally, even if it is a slight contact, it may cause modulation and measurement errors, and the measurement accuracy cannot be guaranteed. Assuming that unmanned automatic measurement is automatically executed, it is not desirable for the measurement operation to continue with a precision measuring instrument that has collided or come into contact with something unintentionally.

[0005] While it may be possible to detect contact between the end effector (or tool) of a typical robot arm using force sensors (such as strain gauges), a certain amount of stopping time and distance is required between contact detection and actual stopping. Therefore, damage to either the measuring instrument (tool) or the workpiece is unavoidable. Furthermore, repairing or calibrating a precision measuring instrument once it malfunctions requires time, effort, and expense.

[0006] The object of the present invention is to provide an automated measurement system and a method for controlling the automated measurement system that can detect hazards before the measuring sensor tool comes into contact with an object during automated measurement, thereby reliably avoiding unintended collisions between the measuring sensor tool and unintended objects.

[0007] An automatic measurement system relating to one side comprises: a measuring sensor tool for measuring the dimensions or shape of an object by detecting the surface of the object with a measuring probe; a moving mechanism for moving the measuring sensor tool relative to the object; a safety monitoring sensor provided to detect a space including the measuring sensor tool itself and the area surrounding the measuring sensor tool; and a safety monitoring determination unit that monitors whether or not there is an object within a preset safety distance d from the outer surface of the measuring sensor tool in the space surrounding the measuring sensor tool.

[0008] This is an overall view of the automated measurement system. This is a diagram of the electric internal diameter measuring instrument. This is a cross-sectional view of the electric internal diameter measuring instrument. This is a functional block diagram of the control unit. This is a diagram illustrating the safety monitoring area. This is an overall flowchart showing an overview of the control operation of the automated measurement system. This is a diagram illustrating the state in which the electric internal diameter measuring instrument is inserted into a hole. This is a diagram illustrating the state in which an object is detected within the safety monitoring area when attempting to insert the electric internal diameter measuring instrument into a hole. This is a diagram illustrating the configuration and procedure for automatically setting the shape data of the measurement sensor tool based on image recognition. This is a diagram illustrating the state in which the measurement sensor tool to be used is stored in the stocker. This is a diagram illustrating an embodiment in which a projector is installed alongside a safety monitoring camera.

[0009] 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, examples, and modifications may be implemented individually, or two or more embodiments, examples, and modifications may be combined. Furthermore, examples of modifications supplemented in individual embodiments, examples, and modifications may be applied to other embodiments, examples, and modifications. (First Embodiment) The first embodiment of the present invention will be described. This embodiment is an automated measuring system for automating the measurement of the dimensions or shape of an object to be measured. In the first embodiment, the case where the measurement target is the inner diameter of a hole formed in the object to be measured (workpiece), and therefore the measuring sensor tool is an electric inner diameter measuring instrument, will be described. Figure 1 is an overall external view of the automated measuring system 1000. The automated measuring system 1000 comprises a measuring device main body 2000 and a control unit 3000 that controls the overall operation.

[0010] (Measuring device main body) The measuring device main body 2000 comprises a multi-joint robot arm (multi-joint robot, moving mechanism) 2100, an electric internal diameter measuring instrument 2200, a support frame (holding part) 2300, and a safety monitoring sensor 2400.

[0011] (Articulated Robot Arm Section) The articulated robot arm section 2100 is a so-called robot arm, and moves the end-effector section 2150, which is the tip of the robot arm section 2100, in three dimensions by multiple rotational drive axes. Furthermore, the measuring device main body section 2000 may have a belt conveyor 2120, a moving stage, and a rotary table, in which case the belt conveyor 2120, the moving stage, and the rotary table are also integrated and controlled as part of the articulated robot arm section 2100. The articulated robot arm section 2100 has a base section 2130 installed on the floor or the like, a multi-axis arm section 2140 supported by the base section 2130, and an end-effector section 2150 provided at the tip of the arm section 2140.

[0012] (Electric Internal Diameter Measuring Instrument) Figure 2 shows the electric internal diameter measuring instrument 2200. Figure 3 is a cross-sectional view of the electric internal diameter measuring instrument 2200. The electric internal diameter measuring instrument 2200 is attached directly or indirectly to the end effector 2150 of the articulated robot arm 2100 as a measuring sensor tool. Here, the electric internal diameter measuring instrument 2200 is attached to the end effector 2150 of the articulated robot arm 2100 by a support frame 2300. The electric internal diameter measuring instrument 2200 motorizes the movement of the rod 2210 of an internal diameter measuring instrument (e.g., a hole test). In other words, the electric internal diameter measuring instrument 2200 moves the rod 2210 up and down (forward and backward) by the power of a motor (electric drive unit) 2220, without manual operation, thereby causing the measuring probe 2271 to move forward and backward automatically.

[0013] The electric internal diameter measuring instrument 2200 has a cylindrical case portion 2230 that surrounds a rod 2210 that moves back and forth in the axial direction. The cylindrical case portion 2230 is a cylindrical case as a whole. The cylindrical case portion 2230 has an upper cylindrical case portion 2240 that constitutes the upper part, an intermediate cylindrical case portion 2250 that constitutes the intermediate part, a lower cylindrical case portion 2260 that constitutes the lower part, and a head cylindrical portion 2270 that constitutes the measuring head portion 2280. The intermediate cylindrical case portion 2250 is attached to the lower end of the upper cylindrical case portion 2240, the lower cylindrical case portion 2260 is attached to the lower end of the intermediate cylindrical case portion 2250, and the head cylindrical portion 2270 is attached to the lower end of the lower cylindrical case portion 2260.

[0014] A displacement detection unit (e.g., an encoder) 2290 is provided inside the intermediate cylindrical case 2250 to detect the displacement or position of the rod 2210. The lower end of the head cylindrical section 2270 is enlarged in diameter, and this enlarged diameter section at the lower end will be referred to as the measuring head section 2280.

[0015] The head cylinder portion 2270 is equipped with measuring probes 2271 that move back and forth in a direction perpendicular to the axial direction of the rod 2210. Three measuring probes 2271 are arranged in the head cylinder portion 2270 at 120° intervals. Each measuring probe 2271 has a thin, round shaft tip 2272 made of carbide at its outer end. When each measuring probe 2271 moves forward in the protruding direction, the round shaft tip 2272 comes into contact with the inner wall of the hole to be measured.

[0016] Each measuring probe 2271 has a tapered surface on its inner end, which contacts the conical surface on the lower end of the rod 2210. The conical surface of the rod 2210 and the tapered surface of the measuring probe 2271 cause the axial movement of the rod 2210 to change direction at a right angle, so that the measuring probe 2271 moves toward the inner wall of the hole.

[0017] A constant pressure mechanism is provided between the motor 2220 and the rod 2210 (in other words, in the power transmission path from the motor 2220 to the measuring probe 2271) to regulate the upper limit of the force (measuring force) acting between the object being measured and the measuring probe 2271. The constant pressure mechanism can be configured, for example, by a ratchet mechanism.

[0018] To measure the inner diameter of a hole to be measured, first, the measuring head 2280 of the electric inner diameter measuring device 2200 is inserted into the hole to be measured by moving the end-effector 2150 of the articulated robot arm 2100. After the measuring head 2280 of the electric inner diameter measuring device 2200 is inserted into the hole to be measured, the measuring probe 2271 is automatically moved forward and backward by the motor drive of the electric inner diameter measuring device 2200, causing the measuring probe 2271 to contact the inner wall of the hole and obtaining the measured value of the hole diameter. Here, the measured value of the hole diameter is obtained by detecting the displacement or position of the rod 2210 with the displacement detection unit (encoder) 2290.

[0019] (Support Frame Section) The support frame section (holding section) 2300 is a holding section for attaching the electric internal diameter measuring instrument (measuring sensor tool) 2200 to the end-effector section 2150 of the articulated robot arm section 2100. The support frame section 2300 is an L-shaped member when viewed from the side and has a support column section 2310 and a support base section 2320. The support base section 2320 is attached perpendicularly to the lower end of the vertical support column section 2310.

[0020] The support column 2310 is located adjacent to and parallel to the electric internal diameter measuring instrument 2200. A restraining means 2330 is provided on the front side of the support column 2310, and the restraining means 2330 switches between holding and releasing the electric internal diameter measuring instrument 2200.

[0021] The support base portion 2320 is provided so as to bend in an L-shape from the lower end of the support column portion 2310 toward the electric internal diameter measuring instrument 2200. The support base portion 2320 has an insertion hole through which the head cylinder portion 2270 of the electric internal diameter measuring instrument 2200 is inserted. The electric internal diameter measuring instrument 2200 is mounted so that, with the head cylinder portion 2270 passing through the insertion hole, the portion above the lower cylinder case portion 2260 is placed on the support base portion 2320 via the floating joint portion 2340.

[0022] (Safety Monitoring Sensor) The safety monitoring sensor 2400 is a sensor that monitors the vicinity of the electric internal diameter measuring instrument (measuring sensor tool) 2200. Here, the safety monitoring sensor 2400 is a camera. The camera that makes up the safety monitoring sensor 2400 is referred to here as the safety monitoring camera 2410. The safety monitoring camera 2410 is installed so as to capture the measuring head portion 2280 of the electric internal diameter measuring instrument (measuring sensor tool) 2200 and its vicinity in its field of view. Two safety monitoring cameras 2410 are provided, and each safety monitoring camera 2410 is a stereo camera. Two projection rods 2420 are attached so as to protrude from the support base portion 2320, and the safety monitoring camera 2410 is installed at the tip of the projection rods 2420. The direction in which the protruding rod 2420 extends is perpendicular to the axis of the cylindrical case portion 2230 of the electric internal diameter measuring instrument (measuring sensor tool) 2200, or more specifically, approximately perpendicular to the axis of the cylindrical case portion 2230 of the electric internal diameter measuring instrument (measuring sensor tool) 2200. Furthermore, the tip of the protruding rod 2420 is slightly bent toward the measuring head portion 2280 so that the safety monitoring camera 2410 can easily capture the measuring head portion 2280 and its surrounding area in its field of view.

[0023] The two protruding rods 2420 protrude in opposite directions, so that the two safety monitoring cameras 2410 can monitor both sides of the electric internal diameter measuring instrument (measuring sensor tool) 2200 with as few blind spots as possible.

[0024] While it is desirable that the entire electric internal diameter measuring instrument (measuring sensor tool) 2200 be within the field of view of the safety monitoring camera 2410 (safety monitoring sensor 2400), it is actually difficult to keep the entire electric internal diameter measuring instrument (measuring sensor tool) 2200 within the field of view of the safety monitoring camera 2410 (safety monitoring sensor 2400). In the operation of moving the electric internal diameter measuring instrument (measuring sensor tool) 2200 toward the measurement target, the area with the highest risk of unintentionally colliding with an unintended object is assumed to be near the measuring probe 2271 of the electric internal diameter measuring instrument (measuring sensor tool) 2200. Furthermore, the most delicate (precise) part of the electric internal diameter measuring instrument (measuring sensor tool) 2200 is near the measuring probe 2271 (i.e., near the measuring head 2280). Therefore, the safety monitoring camera 2410 (safety monitoring sensor 2400) is installed to capture the measuring head section 2280, which is part of the electric internal diameter measuring instrument (measuring sensor tool) 2200, and its immediate surroundings.

[0025] Please note that while we use the term "collision," this refers not only to forceful collisions but also to slight contact. For the 2200 electric internal diameter measuring instrument (measuring sensor tool), which is a precision measuring instrument, any unintended contact that affects measurement accuracy should be considered a "collision."

[0026] The number and installation locations of the safety monitoring cameras 2410 (safety monitoring sensors 2400) are examples only. For example, if the safety monitoring cameras 2410 (safety monitoring sensors 2400) are installed at 90° or 45° intervals to surround the measuring head unit 2280, the resolution and accuracy of the monitoring will increase. If a safety monitoring camera 2410 is also installed on the back (top) of the projection rod, the area around the upper cylinder case 2240 and the intermediate cylinder case 2250 of the electric internal diameter measuring instrument (measuring sensor tool) 2200 can be captured in the field of view. The number and installation locations of the safety monitoring cameras 2410 (safety monitoring sensors 2400) should be appropriately selected considering the shape and size of the measuring sensor tool.

[0027] As illustrated in Figure 2, the measuring head 2280 has a shape that protrudes in diameter, creating a blind spot for the safety monitoring camera 2410 that monitors the vicinity of the measuring head 2280 from above. In this case, the area directly below the measuring head 2280 is in the shadow of the measuring head 2280 itself, creating a blind spot for the safety monitoring camera 2410. The blind spot can be reduced by increasing the length of the projection rod 2420 or by bringing the installation height of the safety monitoring camera 2410 closer to the height of the measuring head 2280. However, if the length of the projection rod 2420 is increased, there is a possibility that it will collide with something, which imposes many constraints on the design of the trajectory of the electric internal diameter measuring instrument (measuring sensor tool) 2200 (i.e., the trajectory of the end effector 2150 of the robot arm 2100). Furthermore, if the installation height of the safety monitoring camera 2410 is set too close to the height of the measuring head unit 2280, it will restrict the depth to which the measuring head unit 2280 can be inserted into the hole of the object to be measured. Therefore, the location and size of the blind spots of the safety monitoring camera 2410 are adjusted as appropriate in trade-offs with other constraints. Here, it is assumed that the area where there is the highest risk of unintentionally colliding with an unintended object during the operation of moving the electric internal diameter measuring instrument (measuring sensor tool) 2200 toward the object to be measured is the outer edge on the lower end of the measuring head unit 2280. Therefore, the safety monitoring camera 2410 (safety monitoring sensor 2400) reliably captures the outer edge on the lower end of the measuring head unit 2280 in its field of view, but it is considered unavoidable that there will be some blind spots in other areas, and it is believed that this will not substantially affect safety.

[0028] In this embodiment, when replacing the electric internal diameter measuring instrument (measuring sensor tool) 2200 depending on the object to be measured or the measurement location, it is assumed that the electric internal diameter measuring instrument (measuring sensor tool) 2200 is removed from the support frame 2300 and only the electric internal diameter measuring instrument (measuring sensor tool) 2200 is replaced. This is because, in this embodiment, the safety monitoring sensor 2400 is attached to the support frame 2300. If the electric internal diameter measuring instrument (measuring sensor tool) 2200 is removed and replaced together with the support frame 2300, the safety monitoring sensor 2400 will be lost. Alternatively, it would be necessary to provide a support frame 2300 with a safety monitoring sensor 2400 attached to every electric internal diameter measuring instrument (measuring sensor tool) 2200, but this would incur significant additional costs. Therefore, it is assumed that the support frame section 2300 and the measuring instrument (measuring sensor tool) will be separated and only the electric internal diameter measuring instrument (measuring sensor tool) 2200 will be replaced. However, if it is not possible to separate the support frame section 2300 and the electric internal diameter measuring instrument (measuring sensor tool) 2200, and it is assumed that the electric internal diameter measuring instrument (measuring sensor tool) 2200 will be removed and replaced together with the support frame section 2300, then the safety monitoring sensor 2400 (safety monitoring camera 2410) should be attached and fixed to the end effector section 2150 of the robot arm section 2100, rather than to the support frame section 2300.

[0029] (Control Unit) Figure 4 is a functional block diagram of the control unit 3000. The control unit 3000 comprises a robot arm drive control unit 3100, a measurement motion control unit 3200, a safety monitoring and judgment unit 3300, and a central control unit 3400.

[0030] The control unit 3000 may consist of hardware or software incorporated into a computer (a so-called computer terminal having a CPU (Central Processing Unit) and ROM and RAM that store predetermined programs) that is electrically / communicatively connected to the measuring device main unit 2000 by wired or wireless means. An operation control program (measurement part program) is installed on the computer terminal, and the operation of the measuring device main unit 2000 is controlled by the execution of the program. The method of supplying the program is not limited; the program may be installed by directly inserting a (non-volatile) recording medium on which the program is recorded into the computer, or a reader device that reads the information of the recording medium may be attached externally to the computer and the program may be installed into the computer from this reader device, or the program may be supplied to the computer via communication lines such as the Internet, LAN cable, telephone line, or wirelessly.

[0031] The robot arm drive control unit 3100 controls the movement of the robot arm unit 2100. The measurement operation control unit 3200 controls the measurement operation of the measurement sensor tool (electric internal diameter measuring instrument 2200).

[0032] The safety monitoring and determination unit 3300 monitors the vicinity of the measuring sensor tool (electric internal diameter measuring instrument 2200) to prevent unintended collisions, based on sensing data from the safety monitoring camera 2410 (safety monitoring sensor 2400). The safety monitoring and determination unit 3300 includes a tool shape data storage unit 3310, a safety distance setting unit 3320, and a safety monitoring area setting unit 3330.

[0033] The tool shape data storage unit 3310 stores the 3D shape data of the electric internal diameter measuring instrument (measuring sensor tool) 2200. The 3D shape data of the electric internal diameter measuring instrument 2200 may be, for example, design CAD data created to manufacture the electric internal diameter measuring instrument 2200. Alternatively, it may be shape data obtained by 3D modeling the electric internal diameter measuring instrument 2200 to obtain its external shape. Here, when the electric internal diameter measuring instrument 2200 is attached to the end effector 2150 of the robot arm 2100, the operator inputs the 3D shape data of the electric internal diameter measuring instrument (measuring sensor tool) 2200 into the control unit 3000 (tool shape data storage unit 3310) according to the type and model of the electric internal diameter measuring instrument 2200.

[0034] The safety distance setting unit 3320 stores one or more safety distances d. The safety distance d is set to, for example, 2 mm. The safety distance d is set to a size that takes into account the driving performance of the robot arm unit 2100 (e.g., stopping distance) and ensures sufficient safety.

[0035] The safety monitoring area setting unit 3330 sets the area from the outer surface of the electric internal diameter measuring instrument (measuring sensor tool) 2200 to the safety distance d as the safety monitoring area 3340. The safety monitoring area 3340 is set by adding the safety distance d to the 3D shape data of the electric internal diameter measuring instrument (measuring sensor tool) 2200 stored in the tool shape data storage unit 3310.

[0036] Figure 5 is an example of a set safety monitoring area 3340. In this embodiment, the area monitored by the safety monitoring camera 2410 is the measuring head portion 2280 and its vicinity, which correspond to the lower part of the lower cylinder case portion 2260. Therefore, the safety monitoring area 3340 is set as an area that takes into account the safety distance d relative to the outer surface of the lower cylinder case portion 2260. Alternatively, the safety monitoring area could be set as an area that is one size larger than the overall shape of the electric internal diameter measuring instrument (measuring sensor tool) 2200 by the amount of the safety distance d. However, in this embodiment, this would be inefficient and would result in a lot of wasted processing power and memory.

[0037] The central control unit 3400 integrally controls the robot arm drive control unit 3100, the measurement motion control unit 3200, and the safety monitoring and judgment unit 3300 so that the automatic measurement system 1000 automatically measures the target locations in order using the electric internal diameter measuring instrument (measuring sensor tool) 2200. Necessary items such as the target location to be measured and the movement path (trajectory) to the location to be measured, as well as the corresponding conditions, are set in advance in the central control unit 3400, and the central control unit 3400 executes a motion control program (measurement part program) to perform a series of measurement operations by the automatic measurement system 1000.

[0038] (Control Operation) The control method for measuring the dimensions (e.g., inner diameter) of a target location using the automated measuring system 1000 configured in this way will now be explained. Figure 6 is an overall flowchart showing an overview of the control operation of the automated measuring system 1000.

[0039] First, as a preliminary step (ST100), the electric internal diameter measuring instrument 2200, which will be used as a measuring instrument, is attached to the end-effector 2150 of the robot arm 2100. Then, the 3D shape data of the electric internal diameter measuring instrument 2200 is set and input into the tool shape data storage unit 3310. As a result, the safety monitoring area setting unit 3330 sets a safety monitoring area 3340 that takes into account the safety distance d in addition to the outer shape of the electric internal diameter measuring instrument 2200 (ST110).

[0040] The robot arm drive control unit 3100 controls the movement of the end-effector 2150 of the robot arm 2100 along a predetermined movement path (trajectory), thereby moving the electric internal diameter measuring instrument 2200 towards the target (ST120). During this time, the safety monitoring camera 2410 monitors the safety monitoring area 3340 to check for any objects in the safety monitoring area 3340 (ST130). If the object to be measured is machined as designed and the robot arm 2100 operates as programmed, the measuring head 2280 of the electric internal diameter measuring instrument 2200 should be inserted into the hole of the object to be measured as planned, without any collisions (ST150). Figure 7 is an example diagram showing the electric internal diameter measuring instrument inserted into the hole.

[0041] Once the measuring head 2280 enters the hole to be measured, the robot arm 2100 stops moving, and the internal diameter of the hole is measured by the automatic measuring function of the electric internal diameter measuring instrument 2200 (ST160). In this case, since it is an electric internal diameter measuring instrument 2200, the motor 2220 drives out three measuring probes 2271, and when the three measuring probes 2271 make even contact with the inner wall of the hole, the measured value of the hole diameter is obtained. Steps ST120 to ST160 are repeated until the internal diameter measurement of all holes is completed.

[0042] Furthermore, during measurement, a part of the electric internal diameter measuring device 2200 (i.e., the measuring probe 2271) comes into contact with the inner wall of the hole being measured. It would be undesirable for the safety monitoring and judgment unit 3300 to excessively judge this as dangerous. Therefore, it is conceivable to turn off the monitoring operation of the safety monitoring and judgment unit 3300 during measurement (ST160). Alternatively, the monitoring operation of the safety monitoring and judgment unit 3300 may be turned off when the robot arm unit 2100 is stopped.

[0043] Here, if the object to be measured is not machined according to the design, or if there is an error in the drive control of the robot arm 2100, the measuring head 2280 of the electric internal diameter measuring instrument 2200 may not enter the hole as intended, and there is a possibility that the measuring head 2280 and the object to be measured will collide. There are various other possible reasons, but as a practical matter, it is necessary to avoid unintentional contact between the measuring instrument and the workpiece, which could result in damage to one or both. For example, as illustrated in Figure 8, suppose that when attempting to insert the measuring head 2280 into the hole, some object (in this case, the edge of the hole, which should not be there) is detected within the safety monitoring area 3340 (ST130:YES). In this case, the safety monitoring and judgment unit 3300 immediately reports the error to the central control unit 3400. Upon receiving the error report, the central control unit 3400 immediately orders the robot arm 2100 to stop driving, thereby stopping the movement of the end-effector 2150 of the robot arm 2100, i.e., the movement of the electric internal diameter measuring device 2200. Because a safety distance d is maintained, the movement of the electric internal diameter measuring device 2200 stops before it actually makes contact (collides) with an object.

[0044] According to the automatic measurement system 1000 of the present embodiment, it is possible to surely prevent the measurement sensor tool (electric inside diameter measuring instrument 2200) from colliding with an unintended object.

[0045] (Second Embodiment) The safety distance d may not be a single fixed value, but may be appropriately changed according to various situations such as the operation mode and the operation speed. For example, the moving process may be divided into a rough moving process and a precise moving process, and the magnitude of the safety distance d may be changed between the rough moving process and the precise moving process. For example, the rough moving process may be a process of moving the electric inside diameter measuring instrument 2200 directly above the hole to be measured (or in front of the entrance of the hole). The precise moving process may be a process of inserting the measuring head portion 2280 of the electric inside diameter measuring instrument 2200 into the hole. At this time, the safety distance d1 in the rough moving process and the safety distance d2 in the precise moving process satisfy "safety distance d1 > safety distance d2". For example, the safety distance d1 is 10 mm and the safety distance d2 is 2 mm. By setting the safety distance d1 relatively large in this way, even if the moving speed in the rough moving process is increased, it is possible to prevent the electric inside diameter measuring instrument 2200 from accidentally colliding with an unintended object. For example, the (relative) moving speed of the electric inside diameter measuring instrument 2200 in the precise moving process is 1 mm / s, while the (relative) moving speed of the electric inside diameter measuring instrument 2200 in the rough moving process may be 20 mm / s.

[0046] Alternatively, the safety distance d may be automatically increased or decreased according to the increase or decrease of the (relative) moving speed of the electric inside diameter measuring instrument 2200 in the moving process. The safety distance d may be automatically set as a function value F(V) having a positive correlation with the (relative) moving speed V (mm / s) of the electric inside diameter measuring instrument (measurement sensor tool) 2200.

[0047] (Third Embodiment) Instead of the operator setting and inputting the shape data of the electric inside diameter measuring instrument (measurement sensor tool) 2200 each time, the automatic measurement system 1000 may automatically recognize the electric inside diameter measuring instrument (measurement sensor tool) 2200. First, assume that the shape data of the measurement sensor tools planned to be used, including various electric inside diameter measuring instruments 2200, is stored in advance in the tool shape data storage unit 3310. The automatic measurement system 1000 automatically recognizes the measurement sensor tool attached to the tip 2150 of the robot arm unit 2100, and then selects the shape data of the corresponding measurement sensor tool from the shape data stored in the tool shape data storage unit 3310.

[0048] There are several conceivable methods for the automatic measurement system 1000 to automatically recognize the measurement sensor tool attached to the tip 2150 of the robot arm unit 2100. (1) The identification label provided on the surface of the measurement sensor tool may be read by the safety monitoring camera 2410 (safety monitoring sensor 2400). In FIG. 2, an example is shown where a two-dimensional code 3311 is provided on the surface of the electric inside diameter measuring instrument (measurement sensor tool) 2200. Such an identification label may be a one-dimensional barcode or an identification number (for example, a manufacturing number) that is a combination of numbers and symbols. It is desirable that the safety monitoring camera 2410 (safety monitoring sensor 2400) also serves to read the identification label, but a dedicated camera for reading the identification label may be provided separately.

[0049] (2) When identification information is recorded inside the measurement sensor tool, the identification information of the measurement sensor tool may be electrically read when the measurement sensor tool is attached to the tip 2150 of the robot arm unit 2100. Examples of methods for recording the identification information inside the measurement sensor tool include electronic recording media or magnetic recording media such as IC chips and magnetic memories, and also recording methods that utilize the resistance value of an electric circuit, for example.

[0050] Alternatively, the shape data of the measurement sensor tool itself may be recorded on an IC chip or magnetic memory. In this case, it becomes unnecessary to pre-store the shape data of the measurement sensor tool in the tool shape data storage unit 3310.

[0051] (3) The shape of the measuring sensor tool may be recognized by image recognition using the safety monitoring camera 2410 (safety monitoring sensor 2400). Figure 9 is a diagram illustrating the configuration and procedure for automatically setting the shape data of the measuring sensor tool based on image recognition. Multiple types of measuring sensor tools and their shape data are pre-recorded in pairs in the tool shape data storage unit 3310 (A in Figure 9). The safety monitoring camera 2410 takes a picture of the measuring sensor tool (electric internal diameter measuring instrument 2200) attached to the end effector 2150 of the robot arm 2100, for example, as illustrated in Figure 2, and obtains the image data. The safety monitoring determination unit 3300 then obtains the model shape of the measuring sensor tool (electric internal diameter measuring instrument 2200) from the image data (B in Figure 9). The safety monitoring and determination unit 3300 searches the shape data stored in the tool shape data storage unit 3310, selects the shape data that matches (or has the highest degree of match) the model shape of the measuring sensor tool (electric internal diameter measuring instrument 2200), and determines that the measuring sensor tool is attached to the end effector 2150 of the robot arm unit 2100 (C in Figure 9).

[0052] (4) As illustrated in Figure 10, if the measurement sensor tools to be used are stored in the stocker 2500 and the robot arm 2100 is capable of automatically changing (auto-changing) the measurement sensor tools, the measurement sensor tool attached to the end-effector 2150 after the change may be identified based on the storage location of the measurement sensor tool. The tool shape data storage unit 3310 is assumed to have multiple types of measurement sensor tools, their shape data, and their storage locations pre-recorded in pairs. The storage location information may be the three-dimensional coordinate values ​​themselves, or it may be the stock location number in the stocker 2500. Whether by automatic execution by the measurement part program or by manual operation by the operator, if the end-effector 2150 of the robot arm 2100 moves to the stocker 2500 and changes the measurement sensor tool there, the measurement sensor tool is identified from the location where it was stored.

[0053] Thus, if the automatic measurement system 1000 can automatically recognize the electric internal diameter measuring instrument (measuring sensor tool) 2200, there will be no need to worry about incorrect input by the operator (or errors in program settings). Even when performing a wide variety of measurements automatically in unmanned automatic measurement, while automatically changing the measuring sensor tool one after another, accidents such as the measuring sensor tool (electric internal diameter measuring instrument 2200) unintentionally colliding with an unintended object will be prevented.

[0054] (Fourth Embodiment) To make it easier for the safety monitoring camera 2410, which serves as a safety monitoring sensor 2400, to detect the presence of an object, a pattern may be projected onto the space to be monitored by, for example, a projector 2430. Figure 11 illustrates an embodiment in which the projector 2430 is installed alongside the safety monitoring camera 2410. The pattern projected from the projector 2430 may be a simple geometric pattern, such as a striped pattern, a grid pattern, or a grid pattern.

[0055] (Fifth Embodiment) As the safety monitoring sensor 2400, LiDAR (Light Detection And Ranging) may be used instead of a camera, or a camera and LiDAR may be used in combination. Furthermore, since the safety monitoring sensor 2400 should be capable of detecting depth, it is preferable to use a so-called 3D camera (not limited to stereo type), a so-called 3D (laser) scanner, or a so-called 3D (laser) scanner, not limited to LiDAR.

[0056] (Sixth Embodiment) In the above embodiment, when an object is detected within the safety monitoring area 3340, the robot arm 2100 is stopped from driving (ST140). Alternatively, a safety monitoring sensor 2400 (safety monitoring camera 2410) may be used to set a target again, and the measuring head 2280 may be guided to reach the measurement point of the actual object to be measured (workpiece) appropriately. For example, if the position of the hole in the object to be measured is misaligned, the safety monitoring determination unit 3300 may inform the central control unit 3400 of the correct target direction or position so that the measuring head 2280 is guided in the direction of the hole, avoiding obstacles (the edge of the hole).

[0057] (Seventh Embodiment) A blind spot occurs in the safety monitoring camera 2410 (safety monitoring sensor 2400) that monitors the vicinity of the measuring head 2280 from above the measuring head 2280. For example, the area directly below the measuring head 2280 is in the shadow of the measuring head 2280 itself and becomes a blind spot for the safety monitoring camera 2410 (safety monitoring sensor 2400). Even if this blind spot cannot be completely eliminated, if the spatial information obtained by the safety monitoring camera 2410 (safety monitoring sensor 2400) is not erased and is stored, the three-dimensional shape of the object (e.g., the object to be measured) can be roughly grasped. That is, by storing the information obtained by the safety monitoring camera 2410 (safety monitoring sensor 2400) during the movement process and integrating it, the safety monitoring determination unit 3300 can grasp the spatial shape of the object to be measured before the object to be measured is hidden directly below the measuring head 2280. Furthermore, if a portion of the object being measured falls into the blind spot of the safety monitoring camera 2410 (safety monitoring sensor 2400), the stored shape of the object being measured can be used to interpolate the data. Based on the relative position and shape information between the electric internal diameter measuring instrument (measuring sensor tool) 2200 and the object (object being measured), monitoring can be continued to check for any unintended objects (such as protrusions left over from machining the object being measured) in the safety monitoring area 3340.

[0058] 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. As a measuring sensor tool, instead of an electric internal diameter measuring instrument, a measuring instrument that measures the dimensions (internal dimensions, external dimensions) of a workpiece (object to be measured) by contact may be used. A measuring sensor tool in which a movable element (measuring probe, measuring jaw, spindle, etc., can be displaceably provided with respect to a fixed element, and the dimensions of a workpiece are measured by bringing the measuring probe into contact with the workpiece or by gripping the workpiece with the measuring probe, can be applied to the above embodiments. Examples of measuring sensor tools include calipers, micrometer heads, micrometers, digital dial gauges (indicators), and test indicators (lever-type dial gauges). Non-contact measuring sensor tools include image measuring instruments with a telecentric lens system, as well as capacitive, laser detectors, and confocal sensors.

[0059] With regard to embodiments including the above examples, the following additional information is disclosed.

[0060] (Note 1) An automatic measurement system comprising: a measuring sensor tool for measuring the dimensions or shape of an object by detecting the surface of the object with a measuring probe; and a moving mechanism for moving the measuring sensor tool relative to the object, the system further comprising: a safety monitoring sensor provided to detect a space including the measuring sensor tool itself and the area surrounding the measuring sensor tool; and a safety monitoring determination unit that monitors whether or not there is an object within a preset safety distance d from the outer surface of the measuring sensor tool in the space surrounding the measuring sensor tool.

[0061] (Note 2) An automatic measurement system as described in Note 1, characterized in that the safety monitoring and determination unit sets a safety monitoring area in the space near the measurement sensor tool, from the outer surface of the measurement sensor tool to a predetermined distance d set in advance.

[0062] (Note 3) An automatic measurement system as described in Note 2, characterized in that shape data of the measurement sensor tool is provided in advance, and the safety monitoring and determination unit sets a region that takes into account the shape of the measurement sensor tool based on the shape data of the measurement sensor tool and adds a safety distance d as the safety monitoring region.

[0063] (Appendix 4) An automatic measurement system as described in Appendix 3, wherein a mark for identifying the shape of the measurement sensor tool is provided on the surface of the measurement sensor tool, and the safety monitoring sensor reads the mark, thereby the safety monitoring determination unit identifies the measurement sensor tool currently in use and identifies the shape of the measurement sensor tool.

[0064] (Appendix 5) An automatic measurement system as described in Appendix 4, characterized in that the label is an identification number of the measurement sensor tool, a one-dimensional barcode, or a two-dimensional code.

[0065] (Note 6) An automatic measurement system as described in Note 3, wherein the measurement sensor tool has an identification information recording unit which is a recording medium that electrically or magnetically records identification information or shape data for identifying the shape of the measurement sensor tool, the moving mechanism holds the measurement sensor tool with a holding unit, and when the measurement sensor tool is attached to the holding unit, the holding unit reads the identification information or shape data of the measurement sensor tool, thereby the safety monitoring and determination unit identifies the measurement sensor tool currently in use and identifies the shape of the measurement sensor tool.

[0066] (Note 7) An automatic measurement system as described in Note 3, wherein the measurement sensor tool to be used is prepared in advance at a predetermined storage location, the moving mechanism holds the measurement sensor tool with a holding part, the measurement sensor tool is attached to the holding part when the holding part moves to the storage location of the measurement sensor tool, and when the measurement sensor tool is attached to the holding part, the safety monitoring and determination unit identifies the measurement sensor tool currently in use and identifies the shape of the measurement sensor tool based on the storage location of the measurement sensor tool.

[0067] (Note 8) An automatic measurement system as described in Note 3, wherein the shape data of the measurement sensor tool to be used is registered in the safety monitoring and determination unit, and the safety monitoring and determination unit identifies the measurement sensor tool currently in use and identifies the shape of the measurement sensor tool based on a comparison between the shape of the measurement sensor tool itself obtained by the safety monitoring sensor detecting the measurement sensor tool itself and the shape data of the measurement sensor tool to be used that has been registered in advance.

[0068] (Note 9) An automatic measurement system as described in Note 1, characterized in that the safety monitoring sensor is a 3D camera or a 3D scanner.

[0069] (Note 10) An automatic measurement system as described in Note 1, characterized in that the safety monitoring sensor is a stereo camera or a LiDAR sensor.

[0070] (Note 11) An automatic measurement system as described in Note 1, wherein the safety monitoring sensor comprises a pattern projection unit that projects a pattern onto the space that the safety monitoring sensor is intended to detect, and a camera.

[0071] (Note 12) An automatic measurement system as described in Note 1, wherein the operation of measuring the dimensions or shape of the object to be measured by the measuring sensor tool comprises a movement step and a measurement step, wherein in the movement step, the movement mechanism moves the measuring sensor tool relative to the object to be measured to a position where the measuring sensor tool can measure the object to be measured set as a measurement target, in the measurement step, the measuring sensor tool measures the object to be measured, and the size of the safety distance d is different between the movement step and the measurement step, or the safety monitoring operation of the safety monitoring determination unit is stopped in the measurement step.

[0072] (Note 13) An automatic measurement system as described in Note 1, wherein the operation of measuring the dimensions or shape of the object to be measured by the measuring sensor tool includes a movement step in which the movement mechanism moves the measuring sensor tool relative to the object to be measured to a position in which the measuring sensor tool can measure the object to be measured, the movement step includes a coarse movement step and a precise movement step, in the coarse movement step the movement mechanism moves the measuring sensor tool relative to the object to be measured to the vicinity of the object to be measured to the vicinity of the object to be measured to the vicinity of the object to be measured, in the precise movement step after the coarse movement step the movement mechanism moves the measuring sensor tool further relative to the object to be measured, and the movement mechanism stops temporarily at a position in which the measuring sensor tool can measure the object to be measured, and the size of the safety distance d is different between the coarse movement step and the precise movement step, or the safety monitoring operation of the safety monitoring determination unit is stopped in the precise movement step.

[0073] (Note 14) An automatic measurement system as described in Note 1, wherein the operation of measuring the dimensions or shape of the object to be measured by the measuring sensor tool includes a movement step in which the movement mechanism moves the measuring sensor tool relative to the object to be measured to a position in which the measuring sensor tool can measure the object to be measured, and in the movement step, the safety monitoring and determination unit is set to increase or decrease the safety distance d in accordance with the increase or decrease in the speed at which the movement mechanism moves the measuring sensor tool relative to the object to be measured.

[0074] (Note 15) An automatic measurement system as described in Note 1, characterized in that when the safety monitoring and determination unit detects that an object is within the safety distance d from the outer surface of the measurement sensor tool, it issues a warning, stops the operation of the moving mechanism, or moves the object back so that the distance between the object and the measurement sensor tool exceeds the safety distance d.

[0075] (Note 16) An automatic measurement system as described in Note 1, wherein when the safety monitoring and determination unit detects that an object is within the safety distance d from the outer surface of the measurement sensor tool, and further, when the object detected by the safety monitoring sensor is the object to be measured, the automatic measurement system is characterized in that, based on the recognition of the shape and position of the object by the safety monitoring sensor, the movement mechanism guides the relative movement of the measurement sensor tool and the object to be measured to a position in which the measurement sensor tool can measure the measurement target location set as the measurement target within the object to be measured.

[0076] (Note 17) An automatic measurement system as described in Note 1, characterized in that the measuring sensor tool is a measuring instrument that measures the dimensions of the object to be measured by bringing a measuring probe into contact with the object to be measured at a predetermined measuring pressure.

[0077] (Note 18) An automatic measurement system as described in Note 1, wherein the measuring sensor tool is an electric internal diameter measuring instrument having: a measuring probe that moves back and forth in a direction intersecting the cylindrical axis of the cylindrical case portion at the tip side of the cylindrical case portion; an electric drive unit that moves the measuring probe back and forth; and a displacement detection unit that detects the displacement of the measuring probe.

[0078] (Note 19) A control method for an automatic measurement system comprising: a measuring sensor tool for measuring the dimensions or shape of an object by detecting the surface of the object with a measuring probe; and a movement mechanism for moving the measuring sensor tool relative to the object, characterized in that a safety monitoring sensor monitors the space including the measuring sensor tool itself and the area surrounding the measuring sensor tool as the object to be detected, and monitors whether there is an object within a preset safety distance d from the outer surface of the measuring sensor tool in the space surrounding the measuring sensor tool.

[0079] 1000 Automatic measuring system 2000 Measuring device main body 2100 Robot arm 2120 Belt conveyor 2130 Base 2140 Arm 2150 End effector 2200 Electric internal diameter measuring instrument 2210 Rod 2220 Motor 2230 Cylinder case 2240 Upper cylinder case 2250 Intermediate cylinder case 2260 Lower cylinder case 2270 Head cylinder 2271 Measuring probe 2272 Round shaft tip 2280 Measuring head 2290 Displacement detector 2300 Support frame 2310 Support column 2320 Support base 2330 Restraining means 2340 Floating joint 2400 Safety monitoring sensor 2410 Safety monitoring camera 2420 Projecting rod 2430 Projector 3000 Control Unit 3100 Robot Arm Drive Control Unit 3200 Measurement Motion Control Unit 3300 Safety Monitoring and Judgment Unit 3310 Tool Shape Data Storage Unit 3320 Safety Distance Setting Unit 3330 Safety Monitoring Area Setting Unit 3340 Safety Monitoring Area 3400 Central Control Unit

Claims

1. An automatic measurement system comprising: a measuring sensor tool for measuring the dimensions or shape of an object by detecting the surface of the object with a measuring probe; and a moving mechanism for moving the measuring sensor tool relative to the object, the system further comprising: a safety monitoring sensor provided to detect a space including the measuring sensor tool itself and the area surrounding the measuring sensor tool; and a safety monitoring determination unit that monitors whether or not there is an object within a preset safety distance d from the outer surface of the measuring sensor tool in the space surrounding the measuring sensor tool.

2. An automatic measurement system according to claim 1, characterized in that the safety monitoring and determination unit sets a region in the space near the measuring sensor tool, from the outer surface of the measuring sensor tool to a predetermined distance d set in advance, as a safety monitoring region.

3. An automatic measurement system according to claim 2, characterized in that shape data of the measurement sensor tool is provided in advance, and the safety monitoring determination unit sets a region that takes into account the shape of the measurement sensor tool based on the shape data of the measurement sensor tool plus a safety distance d as the safety monitoring region.

4. An automatic measurement system according to claim 3, wherein a mark for identifying the shape of the measurement sensor tool is provided on the surface of the measurement sensor tool, and the safety monitoring sensor reads the mark, thereby the safety monitoring determination unit identifies the measurement sensor tool currently in use and identifies the shape of the measurement sensor tool.

5. An automatic measurement system according to claim 4, characterized in that the label is an identification number of the measurement sensor tool, a one-dimensional barcode, or a two-dimensional code.

6. An automatic measurement system according to claim 3, wherein the measurement sensor tool has an identification information recording unit which is a recording medium that electrically or magnetically records identification information or shape data for identifying the shape of the measurement sensor tool, the moving mechanism holds the measurement sensor tool with a holding unit, and when the measurement sensor tool is attached to the holding unit, the holding unit reads the identification information or shape data of the measurement sensor tool, thereby the safety monitoring and determination unit identifies the measurement sensor tool currently in use and identifies the shape of the measurement sensor tool.

7. An automatic measurement system according to claim 3, wherein the measurement sensor tool to be used is prepared in advance at a predetermined storage location, the moving mechanism holds the measurement sensor tool with a holding part, the measurement sensor tool is attached to the holding part when the holding part moves to the storage location of the measurement sensor tool, and when the measurement sensor tool is attached to the holding part, the safety monitoring and determination unit identifies the measurement sensor tool currently in use and identifies the shape of the measurement sensor tool based on the storage location of the measurement sensor tool.

8. An automatic measurement system according to claim 3, wherein the shape data of the measurement sensor tool to be used is registered in the safety monitoring and determination unit, and the safety monitoring and determination unit identifies the measurement sensor tool currently in use and identifies the shape of the measurement sensor tool based on a comparison between the shape of the measurement sensor tool itself obtained by the safety monitoring sensor detecting the measurement sensor tool itself and the shape data of the measurement sensor tool to be used that has been registered in advance.

9. An automatic measurement system according to claim 1, characterized in that the safety monitoring sensor is a 3D camera or a 3D scanner.

10. An automatic measurement system according to claim 1, characterized in that the safety monitoring sensor is a stereo camera or a LiDAR sensor.

11. An automatic measurement system according to claim 1, characterized in that the safety monitoring sensor comprises a pattern projection unit that projects a pattern onto the space that the safety monitoring sensor is to detect, and a camera.

12. An automatic measurement system according to claim 1, wherein the operation of measuring the dimensions or shape of the object to be measured by the measuring sensor tool comprises a movement step and a measurement step, wherein in the movement step, the movement mechanism moves the measuring sensor tool relative to the object to be measured to a position where the measuring sensor tool can measure the object to be measured set as a measurement target, in the measurement step, the measuring sensor tool measures the object to be measured, and the size of the safety distance d is different between the movement step and the measurement step, or the safety monitoring operation of the safety monitoring determination unit is stopped in the measurement step.

13. An automatic measurement system according to claim 1, wherein the operation of measuring the dimensions or shape of the object to be measured by the measuring sensor tool includes a movement step in which the movement mechanism moves the measuring sensor tool relative to the object to be measured to a position in which the measuring sensor tool can measure the object to be measured, the movement step includes a coarse movement step and a precise movement step, in the coarse movement step, the movement mechanism moves the measuring sensor tool relative to the object to be measured to the vicinity of the object to be measured to the vicinity of the object to be measured to the vicinity of the object to be measured to the vicinity of the object to be measured, in the precise movement step, after the coarse movement step, the movement mechanism moves the measuring sensor tool further relative to the object to be measured, and the movement of the movement mechanism is temporarily stopped at a position in which the measuring sensor tool can measure the object to be measured, and the size of the safety distance d is different between the coarse movement step and the precise movement step, or the safety monitoring operation of the safety monitoring determination unit is stopped in the precise movement step.

14. An automatic measurement system according to claim 1, wherein the operation of measuring the dimensions or shape of the object to be measured by the measuring sensor tool includes a movement step in which the movement mechanism moves the measuring sensor tool relative to the object to be measured to a position in which the measuring sensor tool can measure the object to be measured, and in the movement step, the safety monitoring and determination unit is set to increase or decrease the safety distance d in accordance with the increase or decrease in the speed at which the movement mechanism moves the measuring sensor tool relative to the object to be measured.

15. An automatic measurement system according to claim 1, characterized in that when the safety monitoring and determination unit detects that an object is within the safety distance d from the outer surface of the measurement sensor tool, it issues a warning, stops the operation of the moving mechanism, or moves the object back so that the distance between the object and the measurement sensor tool exceeds the safety distance d.

16. An automatic measurement system according to claim 1, wherein when the safety monitoring determination unit detects that an object is within the safety distance d from the outer surface of the measurement sensor tool, and further, when the object detected by the safety monitoring sensor is the object to be measured, the automatic measurement system is characterized in that, based on the recognition of the shape and position of the object by the safety monitoring sensor, the movement mechanism guides the relative movement of the measurement sensor tool and the object to be measured to a position in which the measurement sensor tool can measure the measurement target location set as the measurement target within the object to be measured.

17. An automatic measurement system according to claim 1, characterized in that the measuring sensor tool is a measuring instrument that measures the dimensions of an object by bringing a measuring probe into contact with the object to be measured at a predetermined measuring pressure.

18. An automatic measuring system according to claim 1, wherein the measuring sensor tool is an electric internal diameter measuring instrument having: a measuring probe that moves back and forth in a direction intersecting the cylindrical axis of the cylindrical case portion at the tip side of the cylindrical case portion; an electric drive unit that moves the measuring probe back and forth; and a displacement detection unit that detects the displacement of the measuring probe.

19. A control method for an automatic measurement system comprising: a measuring sensor tool for measuring the dimensions or shape of an object by detecting the surface of the object with a measuring probe; and a movement mechanism for moving the measuring sensor tool relative to the object, characterized in that a safety monitoring sensor monitors the space including the measuring sensor tool itself and the area surrounding the measuring sensor tool as the object to be detected, and monitors whether there is an object within a preset safety distance d from the outer surface of the measuring sensor tool in the space surrounding the measuring sensor tool.

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