Sensor mount and robot system

Abstract

Sensor holder (1) which is equipped with the following: a frame member (11, 12) supporting an acceleration sensor (4) and a circular arc member (11a, 12a) holding an outer periphery of a tool (5) of a robot (2) in a state in which a circumferential direction gap (17a, 17b) is defined in at least one section of the circular arc member (11a, 12a) in a circumferential direction; a screw (14, 15) screwed into the frame member (11, 12) to reduce the circumferential direction gap (17a, 17b); and. a support member (16) whose end section is coupled to the circular arc member (11a, 12a) of the frame member (11, 12), wherein the support member (16) extends in a longitudinal direction of the tool (5), wherein the acceleration sensor (4) is fixed to the other end section of the support member (16).

Description

[0001] The present invention relates to a sensor holder and a robot system and in particular to a sensor holder for temporarily fixing an accelerometer to a tool of a robot.

[0002] Traditionally, for a robot with a moving part, such as a tool, an accelerometer is used to detect movement of the moving part. This is described, for example, in the publications JP 2017 - 074 647 A, JP 2013 – 106 706 A, JP 2009 - 202 235 A and JP H09 - 070 716 A.

[0003] From publication DE 20 2006 007 733 U1, a knuckle-arm robot with a rotary arm is also known, which carries a holding device extending laterally outwards from the rotary arm. The holding device is attached to the rotary arm in a first section close to the rotary arm and carries a torch, such as a welding torch with a torch head, for machining a workpiece in a second section located laterally away from the robot's rotary arm. A further axis of rotation is provided on the torch side of the second section of the holding device.

[0004] The publication EP 2 022 609 B1 discloses an industrial robot with a cable holding element that holds a cable with a hub element. The robot consists of a forearm with a tool management and transfer device and a wrist with a working tool at its distal end. The hub element is connected to the working tool and runs along the wrist over the tool management and transfer device.

[0005] The forearm contains a reduction gear that reduces the rotational speed of a drive source to power the forearm. The wrist assembly consists of a first wrist assembly connected to the forearm and a second wrist assembly connected to the first wrist assembly. A cable is provided to guide the hub assembly through the forearm, the first wrist assembly, and the second wrist assembly. One end of the cable is inserted into the first wrist assembly, and the other end is held by the cable retainer on the second wrist assembly to limit the cable's axial movement.

[0006] The publication EP 1 163 985 B1 discloses a hand flange of a robot hand with an attachment for receiving an auxiliary device, such as a measuring element, a sensor, or an additional or auxiliary tool. The attachment has a retaining ring designed as a hinged clamp, which is held in a circumferential groove of the hand flange.

[0007] Patent application US 2018 / 0169873A1 discloses a camera for observing the interior of a shielded cell, comprising a mount with a spring-shaped gripper for attachment to a remote manipulation arm that performs an observation task. A separate arm is used to apply force to open the spring's branches, thereby holding the camera securely in place while allowing for easy removal. A stop mechanism ensures the camera is at the correct angle and prevents its mount from rotating around the arm. This allows for precise positioning by a further remote manipulation mechanism.

[0008] Publication US 2011 / 0252915A1 discloses an industrial robot consisting of: a tool assembly section on which a tool is to be mounted; a tool assembly rotary arm for rotatably supporting the tool assembly section; a pivot arm for pivotally supporting the tool assembly rotary arm via a pivot shaft; a shoulder for rotatably supporting the rocker arm via a rocker arm pivot shaft; a forearm for rotatably supporting the shoulder via an upper arm pivot shaft; a rotary frame for rotatably supporting the forearm via a forearm pivot shaft; a tube running along the forearm from the rotary frame to the shoulder; and a robot base for rotatably supporting the rotary frame via a rotary frame pivot shaft.In this case, a flow path for supplying drive gas to the tool assembly section is arranged from the robot base to the tool assembly section through the interiors of the rotating frame, the tube, the shoulder, the swing arm and the tool assembly rotating arm.

[0009] Publication JP 2010-032 339 A further discloses a position measurement method applied to a device constructed in such a way as to calculate a correction value for master data serving as a reference for the position of an object, based on the position data obtained by measuring the object, and to perform an operation on a prescribed part of the object based on the corrected position data, in which the correction value is added to the master data.

[0010] In recent years, a robot has been proposed that performs various machining processes, such as laser cutting, laser welding, arc welding and sealing, using a tool connected to the tip end of a robot arm, with the trajectory of the tool's tip end being optimized using machine learning based on the trajectory of the tool's tip end detected by an accelerometer.

[0011] In such an application, it is preferred to position the accelerometer near the tip of the tool to detect an accurate trajectory. Furthermore, the accelerometer must be stably fixed to the tool so that its position and orientation relative to the tip cannot change.

[0012] However, it is difficult to securely fix an accelerometer near the tip of a tool, as there is no space on the tool itself for mounting. Therefore, a method for the temporary and easy attachment of an accelerometer to a tool is desirable. Furthermore, given the existence of various machining tools with different outer diameters, a versatile method for attaching an accelerometer to tools with varying outer diameters is needed.

[0013] The present invention is made in light of the above circumstances, and an object of the present invention is to provide a versatile sensor mount that can temporarily and easily fix an accelerometer to a section near the tip end of a tool, and a robot system with such a sensor mount. This object is achieved by a sensor mount having the features of claim 1 and by a robot system having the features of claim 8. Advantageous embodiments of the invention are the subject of the dependent claims.

[0014] To solve the above problem, the present invention provides the following means.

[0015] One aspect of the present invention provides a sensor holder comprising: a frame member supporting an acceleration sensor and a circular arc member holding an outer periphery of a robot tool in a state in which a circumferential direction gap is defined in at least one section of the circular arc member in a circumferential direction; and a screw screwed into the frame member to reduce the circumferential direction gap.

[0016] In accordance with this design, the frame member is positioned around the outer periphery of the tool, so that the circular arc member holds the outer periphery of the tool. The screw is screwed into the frame member to reduce the circumferential gap, thereby positioning the inner surface of the circular arc member tightly against the outer periphery of the tool. The frame member can be fixed to the outer periphery of the tool by friction between the inner surface of the circular arc and the outer periphery. When the accelerometer is not required, the frame member can be easily removed from the tool by unscrewing the screw.

[0017] As described above, the frame member is mechanically fixed to the tool by screwing in the screw. This makes it possible to temporarily and easily fix the frame member to the tool.

[0018] Furthermore, by fixing the frame member to the tool itself, the accelerometer supported by the frame member can be stably fixed to a section near the tip of the tool. In addition, the circumferential gap allows the inner diameter of the circular arc member to be adjusted to match the outer diameter of the tool. This makes it possible to fix the frame member to tools with different outer diameters, providing a versatile sensor mount.

[0019] In this aspect, the frame member can comprise a first frame member and a second frame member, and the screw can comprise a first screw and a second screw, wherein the first screw reduces the circumferential gap between an end section of the first frame member and an end section of the second frame member, and the second screw reduces the circumferential gap between the other end section of the first frame member and the other end section of the second frame member.

[0020] According to this configuration, the first and second frame members can be attached radially around the outer periphery of the tool. This makes it easier to position the frame member on the outer periphery of the tool.

[0021] According to the invention, a support member is further provided, one end section of which is coupled to the circular arc member of the frame member, wherein the support member extends in a longitudinal direction of the tool, and wherein the acceleration sensor can be fixed to the other end section of the support member.

[0022] According to the invention, when using a long tool, it is possible to position the acceleration sensor on a section near the tip end of the tool, while the frame member is fixed on the outer periphery of the tool at a position spaced away from the tip end of the tool.

[0023] In this aspect, the coupling position of the support member on the circular arc member can be changed in a longitudinal direction of the support member.

[0024] According to this configuration, it is possible to position the accelerometer closer to the tip end of the tool by adjusting the coupling position between the support member and the circular arc member.

[0025] In this aspect, the coupling angle of the support member to the circular arc member can be changed.

[0026] According to this configuration, it is possible to position the acceleration sensor closer to the tip end of the tool by adjusting the coupling angle between the support member and the circular arc member.

[0027] In this aspect, an elastic link can also be provided on an inner surface of the circular arc link, wherein the elastic link is elastically compressible.

[0028] According to this configuration, the inner surface of the circular arc member is more firmly attached to the outer periphery of the tool by compressing the elastic link. This makes it possible to fix the frame member more securely to the tool.

[0029] In this aspect, an anti-slip element can also be provided on an inner surface of the circular arc element.

[0030] In this configuration, the anti-slip element prevents the circular arc element from slipping on the outer periphery of the tool. This makes it possible to fix the frame element more securely to the tool.

[0031] In this respect, the screw can be a knurled screw.

[0032] With this configuration, an operator can manually screw the knurled screw in and out without the use of a tool. Furthermore, it is possible to ensure adequate fastening force by optimizing the diameter of the knurled screw head section.

[0033] Another aspect of the present invention provides a robot system comprising: a robot; a tool connected to a tip end of a robot arm of the robot; the sensor holder according to one of the above described, wherein the sensor holder is attached to the tool; and an accelerometer supported by the sensor holder, wherein an arm segment at a most distal end of the robot arm has a bore that penetrates the arm segment along a rotation axis line of the arm segment, and a control cable of the accelerometer is fed through the bore of the arm segment at the most distal end.

[0034] According to the present invention, it is possible to achieve an advantageous effect by providing a versatile sensor holder that can temporarily and easily fix an accelerometer to a section near a tip end of a tool. Fig. Figure 1 is a schematic view showing an overall configuration of a robot system according to an embodiment of the present invention. Fig. Figure 2 is a perspective view of a sensor mount according to an embodiment of the present invention. Fig. 3 is a top view of the Fig. 2 sensor mount shown when viewed from a base end of a tool. Fig. 4 is a side view of the in Fig. 2 sensor mounts shown. Fig. Figure 5 is a side view of a modified example of the in Fig. 2 sensor mounts shown.

[0035] In the following, a sensor holder 1 and a robot system 10 according to an embodiment of the present invention are described with reference to the drawings.

[0036] According to the presentation in Fig. 1 comprises the robot system 10 according to this embodiment: a robot 2 with a tool 5; a control device 3 that controls the robot 2; the sensor holder 1, which is removable from the tool 5; and an accelerometer 4, which is fixed to the sensor holder 1.

[0037] Robot 2 comprises a robot arm 2a with joints, and the tool 5 is connected to a tip end of the robot arm 2a. For example, robot 2 is a 6-axis articulated robot. The tool 5 is intended for machining operations such as laser cutting, laser welding, arc welding, sealing, painting, or deburring. Such machining operations require precise control of the trajectory of a small-diameter tip end 5a of the tool 5. The tool 5 has a circular cross-sectional shape essentially along its entire length.

[0038] The control device 3 is connected to the robot 2 and the tool 5. The control device 3 comprises a control unit (not shown) with a processor or the like and a memory unit (not shown) with non-volatile memory, ROM, RAM, or the like. The memory unit stores a machining program. The control unit transmits control commands to the servo motors of the joints of the robot arm 2a and the tool 5 to drive them, based on the machining program. Thus, the robot arm 2a and the tool 5 are operated according to the machining program, and a workpiece is subjected to machining by the tip 5a of the tool 5, which moves along a predetermined trajectory.

[0039] Furthermore, the control device 3 is connected to the acceleration sensor 4 via a control cable 6. The control device 3 performs machine learning of the machining program based on the acceleration received from the acceleration sensor 4.

[0040] As in Fig. 2 to Fig. As shown in Figure 4, the sensor holder 1 comprises: a pair of frame members 11 and 12 arranged around an outer periphery of the tool 5; elastic members 13 each arranged on inner surfaces of the frame members 11 and 12; screws 14 and 15 for fastening end sections of the frame members 11 and 12; and a support member 16 coupled to the frame member 11.

[0041] Each of the frame members 11 and 12 is a thin-band plate member, which as a whole is substantially curved and made of a rigid material, such as metal. The first frame member 11 comprises a circular arc member 11a, which is substantially curved in one direction, and end sections 11b and 11c provided at both lateral ends of the circular arc member 11a. The end sections 11b and 11c project outwards along a straight line passing by the lateral ends of the circular arc member 11a. Similarly, the second frame member 12 comprises a circular arc member 12a, which is substantially curved in one direction, and end sections 12b and 12c provided at both lateral ends of the circular arc member 12a. The end sections 12b and 12c project outwards along a straight line that passes by the side ends of the circular arc member 12a.

[0042] According to the presentation in Fig. 3. The frame members 11 and 12, forming a pair, are arranged such that their inner surfaces face radially towards the tool 5 on both sides, so that they surround the tool 5 in the radial direction and hold the outer periphery of the tool 5. In the Fig. In the state shown in Figure 3, the pair of frame members 11 and 12 form a substantially circular partial ring with two circumferential slits 17a and 17b in one circumferential direction. In this state, one end section 11b of the first frame member 11 and one end section 12b of the second frame member 12 face each other, with one circumferential slit 17a located between them. Furthermore, the other end section 11c of the first frame member 11 and the other end section 12c of the second frame member 12 face each other, with the other circumferential slit 17b located between them. It is preferred that the circumferential slits 17a and 17b are located at positions that face each other in a radial direction of the tool 5.

[0043] The end sections 11b and 12b include a bore 11d and 12d, respectively, through which a first screw 14 is inserted, and the end sections 11c and 12c include a bore 11e and 12e, respectively, through which a second screw 15 is inserted. The bores 11d and 11e of the first frame member 11 are through bores with an inner diameter larger than the nominal diameter of the screws 14 and 15. The bores 12d and 12e of the second frame member 12 are screw bores with an internal thread on their inner surfaces, into which the screws 14 and 15 are screwed. The screws 14 and 15 are knurled screws with knurling on surfaces of their head sections 14a and 15a. An operator can easily rotate the head sections 14a and 15a, which are held by the operator's hand, and can easily screw the screws 14 and 15 into and out of the screw holes 12d and 12e by hand.

[0044] The elastic elements 13 are elastically compressible, layered elements. It is preferred that at least one partial surface of each of the elastic elements 13, which is brought into contact with the outer periphery of the tool 5, has a high coefficient of friction, so that it acts as a sliding resistance at the outer periphery of the tool 5. It is preferred that the elastic elements 13 have a rubber-like elasticity, and an example of the elastic element 13 is a layer of rubber. The elastic elements 13 cover substantially the entire inner surfaces of the circular arc elements 11a and 12a, respectively, and are fixed to the inner surfaces of the corresponding circular arc elements 11a and 12a.

[0045] As long as the elastic elements 13 prevent direct contact between an outer surface of the tool 5 and the inner surfaces of the circular arc members 11a and 12a, the elastic elements 13 can only partially cover the inner surface of the circular arc members 11a and 12a. For example, several elastic elements 13 with a gap between them can be provided across the entire inner surfaces of the circular arc members 11a and 12a.

[0046] Furthermore, 13 separate anti-slip elements can be fixed to the inner surfaces of the circular arc elements 11a and 12a of the elastic elements.

[0047] The support member 16 is a flat and thin-banded plate member and has a substantially rectangular shape with a longitudinal axis. The support member 16 extends from the first frame member 11 in a plane perpendicular to a plane defined by the first frame member 11 (a plane parallel to a paper plane). Fig. 3. (in the direction of the plane). In a state where the frame members 11 and 12 are fixed to the tool 5, the support member 16 extends in a longitudinal direction of the tool 5. One end section of the support member 16 is fixed to an outer surface of the first frame member 11 by a pair of threaded bolts 18. The other end section of the support member 16 includes a sensor mounting area to which the accelerometer 4 is attached.

[0048] The machining tool 5 is often configured such that its tip end section has an outer diameter smaller than that of the base end section, which is fixed to the tip end of the robot arm 2a. Thus, the tip end section of the support member 16 can be distinguished from the base end section of the support member 16 as shown in the illustration. Fig. 5 be shifted inwards, so that the tip end section of the support member 16 is provided closer to the longitudinal axis of the tool 5 than a base end section of the support member 16.

[0049] As an example, the accelerometer 4 is a 3-axis accelerometer or a 6-axis accelerometer. The accelerometer 4 is fixed to the sensor mounting area of ​​the support member 16 using any fixing means, such as screws and magnets. The control cable 6 is connected to a terminal 4a of the accelerometer 4. The control cable 6 is routed in Fig. 2 to Fig. 5 not shown.

[0050] Instead of the wired accelerometer 4, a wireless accelerometer 4 can be used. If a wireless accelerometer 4 is used, the control cable 6 is not required.

[0051] According to the presentation in Fig. 2 One end section of the support member 16 is provided with bores 16a arranged in two rows spaced apart along the width of the support member 16. Each bore 16a penetrates the support member 16 in its thickness direction. In each row, the bores 16a are spaced apart along the length of the support member 16. Two threaded bores (not shown) are defined in the outer surface of the first frame member 11. By selecting one of the bores 16a in each row and screwing the threaded bolts 18 into the two threaded bores of the first frame member 11 through the selected bores 16a, the support member 16 can be fixed to the first frame member 11.Furthermore, by changing the positions of the selected bores 16a in each row, it is possible to change the coupling positions of the support member 16 on the first frame member 11 in a longitudinal direction and a coupling angle of the support member 16 with respect to the first frame member 11.

[0052] Next, the effects of sensor mount 1 and robot system 10 according to this configuration will be described.

[0053] During machine learning, the sensor holder 1 is fixed to the tool 5 after the machining program guides the trajectory of the tip end 5a of the tool 5. The operator positions the pair of frame members 11 and 12 radially at the two end faces of the tool 5, inserts the first screw 14 into the bores 11d and 12d, inserts the second screw 15 into the bores 11e and 12e, and tightens the screws 14 and 15 in the screw bores 12d and 12e, respectively.

[0054] During the process of screwing in the screws 14 and 15, the circumferential gap 17a between the end sections 11b and 12b and the circumferential gap 17b between the end sections 11c and 12c gradually decrease, the distance between the pair of circular arc links 11a and 12a also gradually decreases, and finally the inner surfaces of the circular arc links 11a and 12a are attached tightly to the outer periphery of the tool 5 via the elastic links 13. This fixes the frame links 11 and 12 to the outer periphery of the tool 5 and positions the accelerometer 4, which is supported by the first frame link 11 via the support link 16, near the tip end 5a of the tool 5.

[0055] In Fig. 1 to Fig. In section 5, the frame members 11 and 12 are fixed to the base end section of the tool 5. However, the frame members 11 and 12 can be fixed to the tool 5 at a position closer to the tip end 5a.

[0056] The operator then adjusts the coupling position and coupling angle of the support member 16 to the first frame member 11 as required, so that the acceleration sensor 4 can be positioned closer to the tip end 5a of the tool 5.

[0057] Next, robot 2 performs machine learning. During machine learning, the control device 3, by operating robot 2 according to the machining program, moves the tip end 5a of the tool 5 along the specified trajectory. Due to vibrations, deflection, and the like of the tool 5, a difference could occur between the specified trajectory and the actual trajectory of the tip end 5a. As the tip end 5a moves along the trajectory, the accelerometer 4 detects the acceleration over time and transmits the result of this detection to the control device 3. The control device 3 calculates the actual trajectory of the tip end 5a from the acceleration detected by the accelerometer 4.The control device 3 repeats the correction of the control commands to the servomotors of the robot arm 2a and the calculation of the actual trajectory of the tip end 5a and learns control commands to the servomotors with which the difference between the instructed trajectory and the actual trajectory is reduced to a minimum.

[0058] After machine learning, the operator removes screws 14 and 15 from the pair of frame links 11 and 12 and sensor holder 1 from tool 5. The machining program is then executed, and the robot arm 2a is operated according to the learned control commands. In this machining program, following machine learning, the operation of the robot arm 2a is controlled in such a way that vibrations of the tip end 5a of tool 5 are suppressed, thereby ensuring that the trajectory of the tip end 5a of tool 5 matches the instructed trajectory. This enables accurate machining of the workpiece.

[0059] As described above, according to this embodiment, the pair of frame members 11 and 12 can be easily fixed to the tool 5 by mechanically fastening the screws 14 and 15. Thus, the accelerometer 4 can be temporarily and easily fixed to the tool 5 when needed, and easily removed from the tool 5 when not required. In particular, when knurled screws are used as screws 14 and 15, the operator is able to attach and detach the sensor holder 1 from the tool 5 more easily without the use of any tools.

[0060] Furthermore, since the frame members 11 and 12 are fixed to the tool 5 itself, the length of the projecting support member 16 can be reduced compared to a case where the sensor holder 1 is fixed to the tip end section of the robot arm 2a. This makes it possible to achieve high rigidity of the support member 16 and to prevent displacement of the tip end section of the support member 16 due to vibrations and bending. In particular, it is possible to maintain the relative positions and orientations of the accelerometer 4 and the tip end 5a of the tool 5 during movement of the robot arm 2a and to accurately detect the acceleration of the tip end 5a with the accelerometer 4.

[0061] Furthermore, the machining tool 5 includes tools with different outer diameters. According to this embodiment, the distance between the pair of circular arc links 11a and 12a can be changed based on the thread size of the screws 14 and 15. Thus, it is possible to fix the pair of frame links 11 and 12 to the tools 5 with different outer diameters. In particular, it is not necessary to prepare the sensor holder 1 for each of the tools 5, and the sensor holder 1, which is usually used for machine learning with different types of tool 5, can be used. As described above, it is possible to provide the versatile sensor holder 1.

[0062] Furthermore, the inner surfaces of the circular arc links 11a and 12a are more firmly attached to the outer periphery of the tool 5 by compressing the elastic links 13, which are positioned between the outer periphery of the tool 5 and the inner surfaces of the circular arc links 11a and 12a. This makes it possible to fix the frame links 11 and 12 more securely to the tool 5. Additionally, if the elastic links (anti-slip links) 13 are made of a material with a high coefficient of friction, such as rubber, slippage of the frame links 11 and 12 on the outer surface of the tool 5 is prevented by the elastic links 13. This also makes it possible to fix the frame links 11 and 12 more securely to the tool 5. Furthermore, the elastic links 13 protect the outer periphery of the tool 5 from direct contact with the frame links 11 and 12, and it is possible to prevent damage to the outer periphery of the tool 5.

[0063] It is noted that applications of the sensor holder 1 and the accelerometer 4 according to this embodiment are not limited to machine learning and may include other uses. For example, during the machining of a workpiece, the accelerometer 4 can detect the acceleration of the tip end 5a of the tool 5, and the control device 3 can control the robot arm 2a based on the detected acceleration.

[0064] Furthermore, according to this embodiment, the tool 5 has a shape with a circular cross-section; however, the shape of the tool 5 to which the sensor holder 1 is applied is not limited to such an example. For instance, the sensor holder 1 can be fixed to an outer surface of the tool 5 in any prism shape with a polygonal cross-section.

[0065] In this embodiment, it is preferred that the support member 16 comprises a strap-like fixing element for fixing the control cable 6 to the support member 16.

[0066] If the control cable 6 is freely movable relative to the accelerometer 4, it can swing or be pulled by the movement of the robot arm 2a, and vibrations and tensile forces of the control cable 6 can be transmitted to the accelerometer 4 via the connector 4a. Noise resulting from such vibrations and tensile forces of the control cable 6 can be included in the acceleration detected by the accelerometer 4. Fixing the control cable 6 to the support element 16 using a fixing element can prevent the occurrence of noise from the control cable 6.

[0067] In this embodiment, the control cable 6 of the accelerometer 4 can be provided in an arm segment 2b at the most distal end of the robot arm 2a.

[0068] In a robot whose joint at the most distal end of the robot arm 2a is a rotary joint, as in the case of a 6-axis articulated robot, the arm segment 2b has a bore 2c at its most distal end, which allows the arm segment 2B to rotate along a rotation axis of the arm segment 2b as shown in Fig. 1 penetrates. The control cable 6 is inserted from a pointed end of the arm link 2b into the bore 2c.

[0069] Because the control cable 6 is contained in the arm section 2b, it is possible to prevent the control cable 6 from interfering with the moving robot arm 2a.

[0070] An insertion opening 8a, which is connected to the bore 2c of the arm member 2b, can be defined in an outer periphery of a tool attachment member 8 at a base end section, so that the control cable 6 can be easily inserted into the arm member 2b at its most distal end. The tool attachment member 8 is a link for connecting the tool 5 to a tip end of the robot arm 2a and is positioned between the arm member 2b at its most distal end and the tool 5.

[0071] A cable channel (not shown) for accommodating various cables is provided in or outside the robot arm 2a. The control cable 6, which extends from the base end of the arm segment 2b to its most distal end, is connected to the control device 3 via the interior or exterior of the cable channel.

[0072] According to this embodiment, the pair of frame members 11 and 12 are arranged in a substantially circular arc that forms a circular partial ring. However, the shape of the frame members 11 and 12 is not limited to this example. For instance, the circular arc members 11a and 12a of the frame members 11 and 12 can be arranged in a substantially V-shape.

[0073] According to this embodiment, the sensor holder 1 comprises a pair of frame members 11 and 12. However, the sensor holder 1 can instead comprise a single frame member in a substantially C-shape with only one circumferential gap defined in one direction. In the case of the single frame member, the distance between the inner surfaces of the frame member can be changed according to the outer diameter of the tool 5 by adjusting the distance between a pair of end sections with the circumferential gap between them.

[0074] According to this embodiment, screws 14 and 15 are knurled screws. However, screws 14 and 15 could instead be screws of a different type that can be screwed in or out manually or with a tool.

[0075] In this embodiment, the frame member 11 supports the accelerometer 4 via the support member 16. However, the frame member 11 can instead support the accelerometer 4 directly. In particular, the sensor holder 1 may not include the support member 16, and an area for sensor mounting to fix the accelerometer 4 may be reserved in the frame member 11 or 12.

[0076] According to the configuration in which the support member 16 is not included as described above, it is also possible to provide the accelerometer 4 near the tip end 5a of the tool 5 by fixing the frame members 11 and 12 to the tool 5 itself. List of reference symbols 1 Sensor holder 2 robots 2a Robot arm 2b Arm segment at the most distal end 2c bore 4 Accelerometer 5 tools 6 control cables 10 robot systems 11, 12 Frame element 11a, 12a Circular arc member 11b, 11c, 12b, 12c end section 13 Elastic link (anti-slip link) 14, 15 screw, knurled screw 14a, 15a Header section 16 Support member 17a, 17b Gap in circumferential direction

Claims

[1] Sensor holder (1) equipped with: a frame member (11, 12) supporting an acceleration sensor (4) and having a circular arc member (11a, 12a) holding an outer periphery of a tool (5) of a robot (2) in a state in which a circumferential gap (17a, 17b) is defined in at least a portion of the circular arc member (11a, 12a) in a circumferential direction; a screw (14, 15) screwed into the frame member (11, 12) for reducing the circumferential gap (17a, 17b); and. a support member (16) having one end portion coupled to the circular arc member (11a, 12a) of the frame member (11, 12), the support member (16) extending in a longitudinal direction of the tool (5), the acceleration sensor (4) being fixed to the other end portion of the support member (16). [2] The sensor mount (1) according to claim 1, wherein the frame member (11, 12) comprises a first frame member (11) and a second frame member (12), and the screw (14, 15) comprises a first screw (14) and a second screw (15), wherein the first screw (14) reduces the circumferential gap (17a) between one end portion of the first frame member (11) and one end portion of the second frame member (12) and the second screw (15) reduces the circumferential gap (17b) between the other end portion of the first frame member (11) and the other end portion of the second frame member (12). [3] The sensor holder (1) according to claim 1, wherein a coupling position of the support member (16) to the circular arc member (11a, 12a) can be changed in a longitudinal direction of the support member (16). [4] Sensor holder (1) according to one of claims 1-3, wherein the coupling angle of the support member (16) to the circular arc member (11a, 12a) can be changed. [5] Sensor holder (1) according to one of claims 1-4, further comprising: an elastic member (13) provided on an inner surface of the circular arc member (11a, 12a), the elastic member (13) being elastically compressible. [6] Sensor holder (1) according to one of claims 1-5, further comprising: an anti-slip member (13) provided on an inner surface of the circular arc member (11a, 12a). [7] Sensor holder (1) according to one of claims 1-6, wherein the screw (14, 15) is a knurled screw. [8] Robot system comprising: a robot (2); a tool (5) connected to a tip end of a robot arm (2a) of the robot (2); the sensor holder (1) according to one of claims 1-7, wherein the sensor holder (1) is attached to the tool (5); and an acceleration sensor (4) supported by the sensor holder (1), wherein an arm member at a most distal end of the robot arm (2a) has a bore (2c) penetrating the arm member along a rotation axis line of the arm member, and a control cable (6) of the acceleration sensor (4) is fed via the bore (2c) of the arm member at the most distal end.

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