Robot tail end pose positioning system

Abstract

The invention discloses a robot tail end pose positioning system which comprises a measured body and a plurality of distance measuring devices. The tested body is rigidly connected with the six-joint robot, and a plurality of tested areas distributed at different positions are arranged on the tested body; the plurality of distance measuring devices are arranged at the side part of a measured object so as to respectively correspond to different measured areas, and each group of distance measuring devices is used for carrying out distance detection on each measured area corresponding to the measured object. The method has the beneficial effects that the position and posture data of the six-joint robot can be obtained at the same time based on one-time measurement of the distance measuring device and decoupling operation, and accurate positioning of the posture of the six-joint robot can be achieved through repeated measurement.

Description

Technical Field

[0001] This application relates to the technical field of robots, and particularly to a robot end pose positioning system. Background Art

[0002] Six-axis robots are multi-joint series-connected, and there are many mechanical components such as motors, reducers, bearings, and connecting rods in the whole structure. This results in a large error in the repeated positioning accuracy of the position and pose at its end.

[0003] In order to be able to quantitatively measure the repeated positioning pose accuracy of the robot end, there are mainly two common methods at present. One is to use a "laser calibrator" to measure the positioning position of the robot end, but the price of the laser calibrator is as high as more than one million, making the positioning cost of the six-axis robot relatively high. The other is to use a wire rope sensor, but the installation of the wire rope sensor is cumbersome, and after installing the sensor, the robot cannot move freely in a large range or at high speed, and may not be able to or be very difficult to be applied to the repeated positioning pose accuracy experiment of the six-axis robot. Summary of the Invention

[0004] One of the purposes of this application is to provide a robot end pose positioning system that can solve at least one of the defects in the above background art.

[0005] To achieve at least one of the above purposes, the technical solution adopted in this application is: a robot end pose positioning system, including a measured object and multiple ranging devices; the measured object is rigidly connected to a six-axis robot, and multiple measured areas distributed at different positions are provided on the measured object; multiple ranging devices are arranged on the side of the measured object to respectively correspond to different measured areas, and each group of ranging devices performs distance detection on each corresponding measured area of the measured object.

[0006] Preferably, the measured object is provided with at least three measured areas, and the measured areas are perpendicular to each other in the same plane.

[0007] Preferably, the measured object is in a cross-shaped structure, and four measured areas are correspondingly formed at the four extending ends of the measured object; the six-axis robot is connected to the center of the measured object.

[0008] Preferably, there are at least two pairs of ranging devices, and at least one pair of ranging devices is used to detect data of the measured object in the X and Y directions, and at least one pair of ranging devices is used to detect data of the measured object in the Z direction.

[0009] Preferably, there are at least three pairs of the ranging devices, including at least one pair of first ranging devices, at least one pair of second ranging devices, and at least one pair of third ranging devices; the first ranging device is used to collect the distance in the Z-axis direction between it and the measured area, and the two first ranging devices in each pair are arranged at 180° around the center of the measured object; the two second ranging devices in each pair are arranged at 90° around the center of the measured object, and one of the second ranging devices in each pair is used to collect the distance in the X-axis direction between it and the corresponding measured area, and the other second ranging device is used to collect the distance in the Y-axis direction between it and the corresponding measured area; the two third ranging devices in each pair are respectively close to two adjacent measured areas, and the two third ranging devices are symmetrically arranged along the X direction or the Y direction to respectively collect the distance in the Y direction or the X direction between it and the corresponding measured area.

[0010] Preferably, the number of the ranging devices is eight, including two pairs of the first ranging devices, one pair of the second ranging devices, and one pair of the third ranging devices; the two pairs of the first ranging devices respectively correspond to the four measured areas.

[0011] Preferably, the ranging device is used to collect the distance from the end of the measured area to itself.

[0012] Preferably, the pose of the six-joint robot is represented by the relative distances O x 、O y and O z from the measured area to the center O of the measured object, and the relative deflection angles θ x 、θ y and θ z ; assuming that the length of the extended end of the measured object is l, the distance data in the Z-axis direction collected by the two pairs of the first ranging devices are l1 and l2 and l3 and l4 respectively, the distance data in the X-axis direction and the Y-axis direction collected by the second ranging device are l5 and l6 respectively, and the distance data collected by the third ranging device are l7 and l8 respectively; then the pose expression of the six-joint robot is as follows:

[0013] O x = l5 + l, O y = l6 + l, O z = (l1 + l2) / 2 or (l3 + l4) / 2;

[0014] θ x = arcsin[(l1 - l2) / 2l], θ y = arcsin[(l3 - l4) / 2l], θ z = arcsin[(l5 - l6) / 2l].

[0015] Preferably, the robot end pose positioning system further includes a base and mounting seats. There are four mounting seats, and the four mounting seats are arranged at equal intervals in a circle along the center of the object to be measured on the base, and the distance measuring devices are correspondingly mounted on the mounting seats.

[0016] Preferably, the distance measuring device uses a laser rangefinder.

[0017] Compared with the prior art, the beneficial effects of this application are as follows:

[0018] Based on the one-time measurement of the distance measuring device and the decoupling operation, the position and attitude data of the six-joint robot can be obtained simultaneously, and through repeated measurements, the precise positioning of the pose of the six-joint robot can be achieved. Description of the Drawings

[0019] Figure 1 It is a schematic structural diagram of the anti-falling device of this application installed on a climbing ladder.

[0020] In the figure: six-joint robot 100, object to be measured 200, extension end 210, first distance measuring device 310, second distance measuring device 320, third distance measuring device 330, base 410, mounting seat 420. Specific Embodiments

[0021] Next, in combination with specific embodiments, this application will be further described. It should be noted that in the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms should not be understood as necessarily referring to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine the different embodiments or examples described in this specification.

[0022] In the description of this application, it should be noted that for orientation terms, if there are terms such as "center", "transverse", "longitudinal", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicating the orientation and position relationship is based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing this application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and should not be construed as limiting the specific protection scope of this application.

[0023] It should be noted that the terms "first", "second", etc. in the description and claims of this application are used to distinguish similar objects and do not necessarily describe a specific order or sequence.

[0024] In this application, unless otherwise clearly specified or limited, terms such as "installed", "connected", "linked", "fixed", etc. should be understood in a broad sense. For example, it can be a connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0025] In this application, unless otherwise clearly specified or limited, the first feature being "above" or "below" the second feature can include the direct contact between the first and second features, or can include the situation where the first and second features are not in direct contact but in contact through other features between them. Moreover, the first feature being "above", "over", and "on top of" the second feature includes the first feature being directly above and obliquely above the second feature, or simply indicating that the horizontal height of the first feature is higher than that of the second feature. The first feature being "below", "beneath", and "underneath" the second feature includes the first feature being directly below and obliquely below the second feature, or simply indicating that the horizontal height of the first feature is lower than that of the second feature.

[0026] The terms "comprising" and "having" in the description and claims of this application, as well as any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products, or devices.

[0027] One preferred embodiment of this application, as Figure 1 shown, a robot end pose positioning system includes a measured object 200 and multiple ranging devices. The measured object 200 is rigidly connected to the six-joint robot 100 so that the position and pose of the six-joint robot 100 can be replaced by the position and pose of the measured object 200 for convenient positioning. The specific structure of the six-joint robot 100 and the specific connection method between it and the measured object 200 are well-known technologies to those skilled in the art, so they will not be elaborated in detail here. Multiple measured areas are provided on the measured object 200 at different positions; multiple ranging devices are arranged on the side of the measured object 200 corresponding to different measured areas, and each ranging device detects the distance to the corresponding measured area of the measured object 200.

[0028] It can be understood that the object to be measured 200 is installed at the end of the six-axis robot 100 and can move along with the six-axis robot 100. Therefore, when positioning the pose of the six-axis robot 100, the distance between each measured area of the object to be measured 200 can be detected simultaneously by multiple distance measuring devices. Based on the decoupling operation of the one-time measurement results of the distance measuring devices, the position and attitude data of the six-axis robot 100 can be obtained simultaneously. At the same time, the object to be measured 200 is driven by the six-axis robot 100 to rotate at multiple angles to achieve measurements at multiple different positions, so as to ensure the accuracy of the pose positioning of the six-axis robot 100.

[0029] It should be noted that the method for the distance measuring device to measure the distance between each measured area of the object to be measured 200 is the triangulation method, and the specific principle is well-known to those skilled in the art, so it will not be elaborated in detail here. There are various specific types of distance measuring devices that can achieve distance measurement, and a common distance measuring device can use a laser rangefinder.

[0030] In this embodiment, the pose of the six-axis robot 100 includes the relative positions along the three directions of X, Y, and Z and the relative attitudes along the three directions of X, Y, and Z. There are various specific shapes of the object to be measured 200 that can be used for pose positioning of the six-axis robot 100, and it only needs to be ensured that the object to be measured 200 has three mutually perpendicular measured areas, that is, the relative changes in the positions and attitudes of the six-axis robot 100 in the three directions of X, Y, and Z can be measured through the corresponding measured areas of the object to be measured 200.

[0031] It can be understood that the measured areas on the object to be measured 200 can be located in the same plane or not in the same plane; if the measured areas are all located in the same plane, it is convenient to arrange the distance measuring devices, and the data measured by the distance measuring devices does not need to be corrected for position. Therefore, in this example, the measured areas on the object to be measured 200 are preferably set in the same plane and perpendicular to each other.

[0032] Specifically, there are various specific structures of the object to be measured 200 that can form the above-mentioned measured areas, such as the object to be measured 200 is a cross structure or a cuboid structure, etc. Since the cross-structured object to be measured 200 can obtain a larger arm span under the condition of lighter mass, which is beneficial to reducing the error when calculating the attitude angle, the cross structure is preferably adopted for the object to be measured 200 in this embodiment, that is, as Figure 1 shown. Then the four extension ends 210 of the object to be measured 200 can correspondingly form four measured areas, and at the same time, the six-axis robot 100 is connected to the center of the object to be measured 200.

[0033] It should be noted that the extension lengths of the four extension ends 210 of the object to be measured 200 may be the same or different; in order to simplify the process of calculating the pose of the six-joint robot 100 subsequently, an equal-length structure is preferably adopted for the four extension ends 210 in this embodiment. The four extension ends 210 can be divided into two pairs according to the alignment relationship, and the two pairs of extension ends 210 are perpendicular to each other. The four extension ends 210 extend in the XY plane, and the Z direction is perpendicular to the plane where the four extension ends 210 are located.

[0034] In this embodiment, the specific number of the ranging devices capable of positioning the pose of the six-joint robot 100 is at least two pairs. At least one pair of ranging devices is used to detect the data of the object to be measured 200 in the X and Y directions, and at least one pair of ranging devices is used to detect the data of the object to be measured 200 in the Z direction.

[0035] It can be understood that from the foregoing content, the pose of the six-joint robot 100 includes the relative positions and relative postures in the XYZ three directions. If the number of ranging devices is two pairs, only one pair of ranging devices needs to simultaneously detect the distances in the X and Y directions of the measured area of the object to be measured 200, that is, this ranging device can simultaneously measure the distances of two measured areas perpendicular to each other in the X and Y directions. Based on the measurement results of this pair of ranging devices, the relative positions of the six-joint robot 100 in the X and Y directions and the relative posture in the Z direction can be calculated; the other pair of ranging devices can calculate the relative postures of the six-joint robot 100 in the X and Y directions and the relative positions in the Z direction by measuring the distance of the object to be measured 200 in the Z direction.

[0036] It should be noted that if the ranging device simultaneously measures the distances of two measured areas of the object to be measured 200, it means that there are position deviations between the ranging device and the two measured areas to be measured. For example, if the ranging device is located on the angular bisector formed by the two measured areas, then when calculating the perpendicular distances between the ranging device and the two measured areas and wanting to perform position transformation, this may affect the accuracy of the calculation results. Therefore, in this embodiment, the number of ranging devices is preferably at least three pairs for easy understanding, and the following will be described in detail.

[0037] Specifically, as Figure 1As shown, the ranging devices respectively include at least a pair of first ranging devices 310, at least a pair of second ranging devices 320, and at least a pair of third ranging devices 330. The first ranging device 310 is used to collect the distance in the Z-axis direction between it and the measured area. The two first ranging devices 310 in each pair are arranged at 180° around the center of the measured object 200. The two second ranging devices 320 in each pair are arranged at 90° around the center of the measured object 200. One of the two second ranging devices 320 in each pair is used to collect the distance in the X-axis direction between it and the corresponding measured area, and the other second ranging device 320 is used to collect the distance in the Y-axis direction between it and the corresponding measured area. The two third ranging devices 330 in each pair are respectively close to two adjacent measured areas, and the two third ranging devices 330 are symmetrically arranged along the X direction or the Y direction to respectively collect the distance in the Y direction or the X direction between it and the corresponding measured area.

[0038] It should be known that since the first ranging device 310 can only measure the distance in the Z direction for one pair of aligned measured areas each time, that is, only the attitude deviation angles of the six-axis robot 100 in the X-axis direction or the Y-axis direction can be obtained. Therefore, to complete the positioning of all poses of the six-axis robot 100, the first ranging device 310 needs to perform at least two measurements at different positions, which will increase the complexity of the measurement process. Therefore, in this embodiment, the number of ranging devices is further preferably eight, including two pairs of first ranging devices 310, one pair of second ranging devices 320, and one pair of third ranging devices 330; the two pairs of first ranging devices 310 respectively correspond to four measured areas, so that all relative positions and relative postures of the six-axis robot 100 in the XYZ three directions can be obtained in one measurement.

[0039] In this embodiment, as Figure 1 shown, the measured area is the extension end 210 of the measured object 100. Then, when measuring the distance between the ranging device and the corresponding measured area, the ranging device can measure the distance at any position with the corresponding measured area. However, considering that the distance from the detection point of the ranging device on the measured area to the center of the measured object 200 needs to be obtained when performing the pose positioning decoupling operation of the six-axis robot 100, for the convenience of calculation, the detection point of the ranging device can be set at the end position of the extension end 210 of the measured object 200, that is, the ranging device is used to collect the distance from the end of the measured area to itself.

[0040] In this embodiment, the pose of the six-axis robot 100 is determined by the relative distances O x , O y and O z from the measured area to the center O of the measured object 200, and the relative deflection angles θ x , θ y and θ zFor representation, it is assumed that the length of the extension end 210 of the object under test 200 is l. The Z-axis direction spacing data collected by the two pairs of first distance measuring devices 310 are l1 and l2, and l3 and l4 respectively. Among them, l1 and l2 correspond to the spacing between the first distance measuring device 310 and the measurement area parallel to the X-axis of the object under test, and l3 and l4 correspond to the spacing between the first distance measuring device 310 and the measurement area parallel to the Y-axis of the object under test; the X-axis direction and Y-axis direction spacing data collected by the second distance measuring device 320 are l5 and l6 respectively, and the spacing data collected by the third distance measuring device 330 are l7 and l8 respectively. Then the pose expression of the six-joint robot 100 is as follows:

[0041] O x = l5 + l, O y = l6 + l, O z = (l1 + l2) / 2 or (l3 + l4) / 2.

[0042] θ x = arcsin[(l1 - l2) / 2l], θ y = arcsin[(l3 - l4) / 2l], θ z = arcsin[(l5 - l6) / 2l].

[0043] It should be noted that for the calculation of the relative deflection angle of the attitude in the Z-axis direction, the spacing between the first distance measuring device 310 and the measurement area parallel to the X-axis of the object under test can be used, or the spacing between the first distance measuring device 310 and the measurement area parallel to the Y-axis of the object under test can be used; of course, in order to further improve the calculation accuracy, the relative deflection angle of the Z-axis can also be calculated simultaneously through the spacing between the first distance measuring device 310 and the measurement area parallel to the X-axis of the object under test and the spacing between the first distance measuring device 310 and the measurement area parallel to the Y-axis of the object under test, and the average value of the two obtained relative deflection angles is calculated.

[0044] It can also be understood that in order to improve the positioning accuracy of the pose of the six-joint robot 100, the six-joint robot 100 can drive the object under test 200 to move multiple times at different angles relative to the distance measuring device, so that the distance measuring device measures different detection points multiple times. After obtaining enough information, the pose data of the six-joint robot 100 at different movement positions are calculated, and these data are averaged to improve the pose positioning accuracy of the six-joint robot 100.

[0045] In this embodiment, as Figure 1 shown, in order to facilitate the installation of the distance measuring device, the robot end pose positioning system further includes a base 410 and a mounting seat 420. The number of mounting seats 420 is four, and the four mounting seats 420 are arranged at equal intervals along the circumference of the center of the object under test 200 on the base 410, and the distance measuring device is correspondingly installed on each mounting seat 420.

[0046] The basic principle, main features and advantages of the present application have been described above. Those skilled in the art should understand that the present application is not limited by the above embodiments. What is described in the above embodiments and the specification is only the principle of the present application. Without departing from the spirit and scope of the present application, there will be various changes and improvements to the present application, and these changes and improvements all fall within the scope of the present application claimed. The scope of protection required by the present application is defined by the appended claims and their equivalents.

Claims

1. A robot end - pose positioning system, characterized in that, Including: The object to be measured; the object to be measured is rigidly connected to a six-axis robot, and a plurality of measurement areas are arranged at different positions on the object to be measured; And A plurality of distance measuring devices; the plurality of distance measuring devices are arranged on the side of the object to be measured to respectively correspond to different measurement areas, and each group of the distance measuring devices measures the distance of the corresponding measurement area of the object to be measured.

2. The robot end pose positioning system according to claim 1, characterized in that, The object to be measured is provided with at least three measurement areas, and the measurement areas are perpendicular to each other in the same plane.

3. The robot end - pose positioning system according to claim 2, wherein, The object to be measured has a cross-shaped structure, and four extension ends of the object to be measured respectively form four measurement areas; the six-axis robot is connected to the center of the object to be measured.

4. The robot end - pose positioning system according to claim 3, wherein, There are at least two pairs of the distance measuring devices, wherein at least one pair of the distance measuring devices is used to detect the data of the object to be measured in the X and Y directions, and at least one pair of the distance measuring devices is used to detect the data of the object to be measured in the Z direction.

5. The robot end - pose positioning system according to claim 4, wherein, There are at least three pairs of the distance measuring devices, which respectively include at least one pair of first distance measuring devices, at least one pair of second distance measuring devices and at least one pair of third distance measuring devices; The first distance measuring device is used to collect the distance in the Z-axis direction between it and the measurement area, and the two first distance measuring devices in each pair are arranged around the center of the object to be measured by 180°; The two second distance measuring devices in each pair are arranged around the center of the object to be measured by 90°, one of the second distance measuring devices in each pair is used to collect the distance in the X-axis direction between it and the corresponding measurement area, and the other second distance measuring device is used to collect the distance in the Y-axis direction between it and the corresponding measurement area; The two third distance measuring devices in each pair are respectively close to two adjacent measurement areas, and the two third distance measuring devices are symmetrically arranged in the X direction or the Y direction to respectively collect the distance in the Y direction or the X direction between it and the corresponding measurement area.

6. The robot end - pose positioning system according to claim 5, wherein, The number of the distance measuring devices is eight, including two pairs of the first distance measuring devices, one pair of the second distance measuring devices and one pair of the third distance measuring devices; the two pairs of the first distance measuring devices respectively correspond to the four measurement areas.

7. The robot end - pose positioning system according to claim 6, wherein, The distance measuring device is used to collect the distance from the end of the measurement area to itself.

8. The robot end pose positioning system according to claim 7, wherein The pose of the six-joint robot is represented by the relative distances O x 、O y and O z from the measured area to the center O of the measured object, and the relative deflection angles θ x 、θ y and θ z of the measured area with respect to the center O of the measured object; Assume that the length of the extension end of the object to be measured is l, the distance data in the Z-axis direction collected by the two pairs of the first distance measuring devices are l1 and l2 and l3 and l4 respectively, the distance data in the X-axis direction and the Y-axis direction collected by the second distance measuring device are l5 and l6 respectively, and the distance data collected by the third distance measuring device are l7 and l8 respectively; then the pose expression of the six-axis robot is as follows: O x = l5 + l,O y = l6 + l,O z = (l1 + l2) / 2 or (l3 + l4) / 2; θ x = arcsin[(l1 - l2) / 2l], θ y = arcsin[(l3 - l4) / 2l], θ z = arcsin[(l5 - l6) / 2l].

9. The robot end pose positioning system according to any one of claims 5-8, characterized in that, The robot end pose positioning system further includes a base and a mounting seat. The number of the mounting seats is four, and the four mounting seats are arranged on the base at equal intervals in a circle along the center of the object to be measured, and the distance measuring devices are correspondingly mounted on the mounting seats.

10. The robot end - pose positioning system according to claim 1, wherein, The distance measuring device uses a laser rangefinder.

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