Curved surface polishing method

Abstract

According to the curved surface polishing method, a first platform and a second platform are arranged, the first platform and the second platform are oppositely arranged, and the first platform and the second platform are fixedly connected based on at least three sets of hinge assemblies; a grinding wheel driving part and an external controller are arranged on the surface, close to the first platform, of the second platform, the external controller is arranged above the grinding wheel driving part, at least three laser induction sensors and a grinding wheel are arranged on the surface, away from the first platform, of the second platform, and the laser induction sensors are arranged around the grinding wheel. Further, the ground curved surface can be sensed in real time based on the dot matrix laser induction sensor, the controller controls stretching and retracting of the hinge assembly in an online closed-loop mode, self-adaptive adjustment of the curved surface contact angle is guaranteed, and the problems that machining is difficult and quality is poor for different positions and different curvatures of the curved surface in a traditional grinding mode are solved; and meanwhile, universality of multiple machining occasions is achieved, and the machining precision is improved.

Description

[0001] The present application is a divisional application of the application date "2024.10.10", the application number "202411407815.1", and the application title "A curved surface polishing device and its polishing method". TECHNICAL FIELD

[0002] The present application relates to the technical field of rail transit vehicles and automobile parts processing, and particularly relates to a curved surface polishing method. BACKGROUND

[0003] In the production and manufacturing process of rail transit vehicles and automobiles, a large number of curved surface parts need to be polished to reduce burrs on the surface. The curved surface parts include rail transit vehicle side wall large parts (at the circular arc), driver's cabin and mask, automobile doors, crankshafts, engine covers, cylinder blocks, etc. With the development of economy and the innovation of industrial technology, the polishing method of curved surface workpieces has changed from traditional manual polishing to robot automatic polishing. The polishing robot manipulator end and the polishing tool are rigidly connected through a flange.

[0004] In the prior art, most of the current robot automatic polishing has high efficiency but poor effect. The current robot polishing program is as follows: marking polishing points that can represent the entire curved surface path on the target workpiece, planning the path according to the polishing points, using a certain motion instruction and control instruction to command the robot executor to implement the polishing work according to the polishing path. However, in the current robot polishing process, the change of curvature is basically not considered, and the polishing point or polishing surface normal is not identified, so that the polishing tool cannot be accurately aligned with the workpiece, resulting in uneven polishing thickness and poor polishing surface precision. SUMMARY

[0005] The main purpose of the embodiment of the present application is to provide a curved surface polishing method, which can realize real-time sensing of the polished curved surface based on a dot matrix laser sensing sensor, and control the extension and retraction of the telescopic rod in an online closed loop, thereby ensuring adaptive adjustment of the curved surface contact angle, improving the processing difficulty and poor quality of different positions and curvatures of the curved surface under the traditional polishing method, and improving the processing precision.

[0006] A curved surface polishing method, characterized in that it comprises:

[0007] a first platform;

[0008] a second platform, the first platform and the second platform being oppositely arranged, and the first platform and the second platform being fixedly connected based on at least three groups of hinge assemblies;

[0009] The second platform is provided with a polishing wheel driving element and an external controller near the surface of the first platform, the external controller is arranged above the polishing wheel driving element, and the second platform is provided with at least three laser sensing sensors and a polishing wheel away from the surface of the first platform, and the laser sensing sensors are arranged around the polishing wheel;

[0010] The polishing wheel is used for polishing a workpiece to be processed, the laser sensing sensors are used for active dot matrix data measurement, and the distance from the surface of the workpiece to be processed below is measured in real time, the external controller is used for calculating the normal information of the curved surface area to be polished on the workpiece to be processed according to the distance obtained by each laser sensing sensor, and controlling the hinge assembly to adjust the angle of the polishing wheel according to the normal information, so that the normal of the polishing wheel coincides with the normal of the curved surface area to be polished.

[0011] The hinge assembly comprises an upper Hooke joint mounting seat, an upper Hooke joint, an extension rod, a lower Hooke joint and a lower Hooke joint mounting seat connected in sequence, the upper Hooke joint mounting seat is fixedly connected with the first platform, and the lower Hooke joint mounting seat is fixedly connected with the second platform.

[0012] The edge of the first platform is provided with a plurality of first mounting protrusions matched with the hinge assembly, the first mounting protrusions are fixedly connected with the upper Hooke joint mounting seat, and the edge of the second platform is provided with a plurality of second mounting protrusions matched with the hinge assembly, the second mounting protrusions are fixedly connected with the lower Hooke joint mounting seat.

[0013] The extension rod is provided with a linear motor driver inside, the linear motor driver is used for driving the extension rod to be elongated or compressed, one end of the extension rod is hingedly connected with the upper Hooke joint, and the other end of the extension rod is hingedly connected with the lower Hooke joint.

[0014] The control method is as follows:

[0015] Three laser sensing sensors are selected from the at least three laser sensing sensors, the projection points of the three laser sensing sensors on the surface of the workpiece to be processed are obtained respectively, and the projection distances of the laser sensing sensors from the surface of the workpiece to be processed are calculated respectively based on each projection point;

[0016] A tool coordinate system is constructed according to the spatial positions of the three selected laser sensing sensors, and sensor position coordinates of the three laser sensing sensors in the tool coordinate system are determined respectively;

[0017] Based on the three sensor position coordinates and the three projection distances, light point position coordinates of the projection points of the three laser sensing sensors in the tool coordinate system are obtained.

[0018] According to the three light point position coordinates, normal information of the curved surface area to be polished on the workpiece to be processed is obtained, and the hinge assembly is controlled to adjust the angle of the polishing wheel according to the normal information, so that the normal of the polishing wheel coincides with the normal of the curved surface area to be polished;

[0019] The normal information of the curved surface area to be polished after the corresponding extension of the plurality of telescopic rods is obtained,

[0020] According to the normal information after the corresponding extension of the plurality of telescopic rods, it is judged whether the polishing wheel still exists deflection;

[0021] If the polishing wheel does not exist deflection, it is determined that the normal of the polishing wheel coincides with the normal of the curved surface area to be polished; if the polishing wheel exists deflection, the extension length of the telescopic rod is continuously adjusted and it is re-judged whether the polishing wheel still exists deflection until the polishing wheel does not exist deflection;

[0022] When the normal of the polishing wheel coincides with the normal of the curved surface area to be polished, the curved surface area to be polished is polished according to preset parameters.

[0023] Preferably, four groups of the hinge assemblies are arranged between the first platform and the second platform, and the second platform away from the surface of the first platform is provided with four laser sensing sensors.

[0024] Preferably, the three light point position coordinates are (x1', y1', z1'), (x2', y2', z2'), and (x3', y3', z3'), and the normal equation of the polishing area of the workpiece to be processed can be calculated according to the three point coordinates as follows:

[0025]

[0026] Preferably, one of the projection light points is in the coordinate plane of the tool coordinate system, which is recorded as a first projection light point, and the laser sensing sensor corresponding to the first projection light point is recorded as a first laser sensing sensor.

[0027] The step of obtaining the light point position coordinates of the projection light points corresponding to the three laser sensing sensors in the tool coordinate system based on the three sensor position coordinates and the three projection distances comprises:

[0028] The first sensor position coordinates of the first laser sensing sensor in the tool coordinate system and the first projection distance between the first laser sensing sensor and the first projection light point are obtained.

[0029] acquire a first included angle between a laser ray emitted by the first laser sensor and the polishing wheel;

[0030] determine a light point position coordinate of the first projection light point in the tool coordinate system according to the first sensor position coordinate, the first projection distance and the first included angle.

[0031] Preferably, the other two laser sensors are respectively referred to as a second laser sensor and a third laser sensor, and the projection light point corresponding to the second laser sensor is referred to as a second projection light point, and the projection light point corresponding to the third laser sensor is referred to as a third projection light point.

[0032] The step of acquiring the light point position coordinates of the projection light points corresponding to the three laser sensors in the tool coordinate system based on the three sensor position coordinates and the three projection distances further comprises:

[0033] acquire a first laser ray intersection point between the first laser sensor and the second laser sensor, and a second laser ray intersection point between the first laser sensor and the third laser sensor;

[0034] calculate a second included angle between the first laser sensor, the second laser sensor and the first laser ray intersection point, and a third included angle between the first laser sensor, the third laser sensor and the second laser ray intersection point;

[0035] acquire a second sensor position coordinate of the second laser sensor in the tool coordinate system, and determine a light point position coordinate of the second projection light point in the tool coordinate system according to the first sensor position coordinate, the second sensor position coordinate and the second included angle;

[0036] acquire a third sensor position coordinate of the third laser sensor in the tool coordinate system, and determine a light point position coordinate of the third projection light point in the tool coordinate system according to the first sensor position coordinate, the third sensor position coordinate and the third included angle.

[0037] Preferably, the light point position coordinate of the first projection light point is F l (x1',y1',z1'), and the light point position coordinate of the first projection light point in the tool coordinate system is determined according to the first sensor position coordinate E1(x1,y1,z1), the first projection distance h l and the first included angle θ as follows:

[0038] x1′=h1cosθ,y1′=0,z1′=z1-h1sinθ

[0039] Preferably, the normal information of the curved surface area to be polished on the workpiece to be processed is obtained according to the three light spot position coordinates, and the angle of the polishing wheel is adjusted by the hinge assembly according to the normal information, so that the normal of the polishing wheel coincides with the normal of the curved surface area to be polished, comprising:

[0040] The normal information of the curved surface area to be polished is obtained according to the three light spot position coordinates, and the deflection direction of the polishing wheel is determined according to the normal information;

[0041] According to the deflection direction, the extension lengths corresponding to the plurality of telescopic rods are calculated, and the plurality of telescopic rods are controlled to extend or retract to adjust the angle of the polishing wheel so that the normal of the polishing wheel coincides with the normal of the curved surface area to be polished.

[0042] The embodiment of the present application has the following beneficial effects: by selecting three laser sensing sensors from at least three laser sensing sensors, the projection light spots of the three laser sensing sensors on the surface of the workpiece to be processed are obtained respectively, and the projection distances of the laser sensing sensors and the surface of the workpiece to be processed are calculated respectively based on each projection light spot; a tool coordinate system is constructed according to the spatial positions of the three selected laser sensing sensors, and the sensor position coordinates of the three laser sensing sensors in the tool coordinate system are determined; based on the three sensor position coordinates and the three projection distances, the light spot position coordinates of the projection light spots corresponding to the three laser sensing sensors in the tool coordinate system are obtained; the normal information of the curved surface area to be polished on the workpiece to be processed is obtained according to the three light spot position coordinates, and the angle of the polishing wheel is adjusted by the hinge assembly according to the normal information, so that the normal of the polishing wheel coincides with the normal of the curved surface area to be polished; when the normal of the polishing wheel coincides with the normal of the curved surface area to be polished, the curved surface area to be polished is polished according to the preset parameters, and then the polishing point or the polishing surface normal can be accurately determined on the curved surface area based on the light spot projection positions of the plurality of projection light spots, the polishing precision of the curved surface is improved, the problem of uneven polishing of the curved surface after conventional polishing is fundamentally solved, the consistency after polishing of the curved surface is ensured, and subsequent coating operation is facilitated. BRIEF DESCRIPTION OF DRAWINGS

[0043] Figure 1 The structure schematic diagram of the curved surface polishing device provided by the embodiment of the present application is shown in the figure;

[0044] Figure 2 The structure schematic diagram of the curved surface polishing device in forward polishing is shown in the figure; Figure 1

[0045] Figure 3 The structure schematic diagram of the curved surface polishing device in lateral polishing is shown in the figure; Figure 1 ​​

[0046] Figure 4 An optional flowchart of the curved surface polishing method provided by the embodiment of the present application is shown in the following figure;

[0047] Figure 5 A schematic diagram of the laser sensing sensor and the corresponding projected light point position provided by the embodiment of the present application is shown in the following figure;

[0048] Figure 6 A schematic diagram of the laser sensing sensor and the corresponding projected light point position provided by the embodiment of the present application is shown in the following figure; Figure 5

[0049] A schematic diagram of the laser sensing sensor and the corresponding projected light point position provided by the embodiment of the present application is shown in the following figure; Figure 7 Figure 6 A schematic diagram of the laser sensing sensor and the corresponding projected light point position provided by the embodiment of the present application is shown in the following figure;

[0050] Figure 8 Figure 7 A schematic diagram of the laser sensing sensor and the corresponding projected light point position provided by the embodiment of the present application is shown in the following figure;

[0051] Figure 9 A schematic diagram of the laser sensing sensor and the corresponding projected light point position provided by the embodiment of the present application is shown in the following figure; Figure 8

[0052] A schematic diagram of the laser sensing sensor and the corresponding projected light point position provided by the embodiment of the present application is shown in the following figure; Figure 10 Figure 9 A schematic diagram of the laser sensing sensor and the corresponding projected light point position provided by the embodiment of the present application is shown in the following figure.

[0053] The drawing label: the first platform 10, the first mounting protrusion 11, the second platform 20, the polishing grinding wheel driving part 21, the external controller 22, the laser sensing sensor 23, the polishing grinding wheel 24, the second mounting protrusion 25, the hinge assembly 30, the upper hooke hinge mounting seat 31, the upper hooke hinge 32, the telescopic rod 33, the lower hooke hinge 34, the lower hooke hinge mounting seat 35, the workpiece to be processed 40. DETAILED DESCRIPTION

[0054] In order to make the purpose, technical scheme and advantages of the present application more clear, the present application is further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application, and are not used to limit the present application.

[0055] It should be noted that although the functional modules are divided in the device schematic diagram, and the logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in a manner different from the module division in the device or the order in the flowchart. The terms "first", "second", etc. in the specification, claims and above drawings are used to distinguish similar objects, and do not necessarily describe a specific order or sequence.

[0056] ​​​Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing embodiments of the invention only and is not intended to limit the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0057] Currently, most robotic grinding processes are highly efficient but have poor surface finish. The current robotic grinding procedure involves marking grinding points on the target workpiece to represent the entire curved surface path, planning the path according to these marked points, and using defined motion and control commands to instruct the robot actuator to perform the grinding operation along the path. However, current robotic grinding processes generally do not consider changes in curvature, fail to identify grinding points or the normals of the grinding surface, resulting in inaccurate alignment between the grinding tool and the workpiece. This leads to uneven grinding thickness and poor surface finish.

[0058] Based on this, a first platform and a second platform are provided, which are arranged opposite to each other and fixedly connected by at least three sets of hinge components. A grinding wheel drive and an external controller are provided on the surface of the second platform near the first platform, with the external controller positioned above the grinding wheel drive. At least three laser sensors and a grinding wheel are provided on the surface of the second platform away from the first platform, with the laser sensors positioned around the grinding wheel. The grinding wheel is used to grind the workpiece, and the laser sensors are used to acquire the distance between the laser sensor and the surface of the workpiece. The distance sensor is used by an external controller to calculate the normal information of the surface area to be ground on the workpiece based on the distances obtained by each laser sensor. Based on the normal information, the controller controls the hinge assembly to adjust the angle of the grinding wheel so that the normal of the grinding wheel coincides with the normal of the surface area to be ground. This allows for real-time sensing of the surface to be ground based on the dot matrix laser sensor. The controller controls the extension and retraction of the hinge assembly in an online closed loop, ensuring adaptive adjustment of the surface contact angle. This improves the problems of difficult processing and poor quality of different curvatures at different positions on the surface under traditional grinding methods. At the same time, it has versatility for multiple processing occasions and high processing accuracy.

[0059] The curved surface grinding device and grinding method provided in the embodiments of the present invention will be specifically described through the following embodiments. First, the curved surface grinding device in the embodiments of the present invention will be described.

[0060] The embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0061] like Figures 1 to 3 As shown, Figure 1 This is a schematic diagram of the curved surface grinding device provided in an embodiment of the present invention. Figure 2For Figure 1 Structure diagram of the camber polishing device when polishing in the forward direction, Figure 3 For Figure 1 Structure diagram of the camber polishing device when polishing in the lateral direction, the camber polishing device provided by the embodiment of the application comprises a first platform 10 and a second platform 20, the first platform 10 and the second platform 20 are oppositely arranged, and the first platform 10 and the second platform 20 are fixedly connected based on at least three hinge assemblies 30; the surface of the second platform 20 close to the first platform 10 is provided with a polishing grinding wheel driving element 21 and an external controller 22, the external controller 22 is arranged above the polishing grinding wheel driving element 21, and the surface of the second platform 20 away from the first platform 10 is provided with at least three laser sensing sensors 23 and a polishing grinding wheel 24, the laser sensing sensors 23 are arranged around the polishing grinding wheel 24.

[0062] The polishing grinding wheel 24 is used for polishing a workpiece 40 to be processed, the laser sensing sensors 23 are used for acquiring the distances between the laser sensing sensors 23 and the surface of the workpiece 40 to be processed, and the external controller 22 is used for calculating the normal information of the camber region to be polished on the workpiece 40 to be processed according to the distances acquired by the laser sensing sensors 23, and controlling the hinge assemblies 30 to adjust the angle of the polishing grinding wheel 24 according to the normal information, so that the normal of the polishing grinding wheel 24 coincides with the normal of the camber region to be polished.

[0063] It should be noted that the hinge assembly 30 comprises an upper Hooke's joint mounting seat 31, an upper Hooke's joint 32, an extension rod 33, a lower Hooke's joint 34 and a lower Hooke's joint mounting seat 35 connected in sequence, the upper Hooke's joint mounting seat 31 is fixedly connected with the first platform 10, and the lower Hooke's joint mounting seat 35 is fixedly connected with the second platform 20.

[0064] Optionally, in the embodiment, the first platform 10 is an upper platform, the upper platform is connected with the end of a robot, the second platform 20 is a lower platform, the first platform 10 and the second platform 20 are provided with four hinge assemblies 30, the surface of the second platform 20 away from the first platform 10 is provided with four laser sensing sensors 23, the four hinge assemblies 30 are arranged at the edge positions of the two platforms, and the hinge assembly 30 can change the length thereof through the extension and contraction of the intermediate extension rod 33; the lower platform is provided with four laser sensing sensors 23, the four laser sensing sensors 23 are arranged around the polishing grinding wheel 24, and the four laser sensing sensors 23 are used for active dot matrix data measurement, and the distance from the four laser sensing sensors 23 to the surface of the workpiece 40 to be processed below is measured in real time.

[0065] Optionally, the workpiece 40 to be processed can be a large part (a circular arc part) of a side wall of a rail transit vehicle, a driver's cabin and a mask or a door of a vehicle, a crankshaft, an engine cover, a cylinder body and the like, and the application is not limited in this way.

[0066] Further, it needs to be explained that the external controller 22 can identify the parameter combination of the four sets of laser sensing sensors and obtain the normal direction of the surface of the workpiece to be processed, and then can sense the contact state of the polishing grinding wheel 24 and the surface of the workpiece to be processed; the external controller 22 drives the telescopic rod 33 to extend or retract to adjust the posture of the polishing grinding wheel 24, and then ensures the polishing direction of the polishing grinding wheel 24 in contact with the curved surface workpiece, and ensures the quality and precision of the polished surface.

[0067] Optionally, in the embodiment, the edge of the first platform 10 is provided with a plurality of first mounting protrusions 11 matched with the hinge assembly 30, the upper Hooke's joint mounting seat 31 is fixedly connected with the first mounting protrusion 11, for example, can be fixedly connected through bolts, and the edge of the second platform 20 is provided with a plurality of second mounting protrusions 25 matched with the hinge assembly 30, the lower Hooke's joint mounting seat 35 is fixedly connected with the second mounting protrusion 25.

[0068] Optionally, the telescopic rod 33 is provided with a linear motor driver (not marked) inside, the linear motor driver is used for driving the telescopic rod 33 to extend or compress, thereby being capable of adjusting the polishing posture, and one end of the telescopic rod 33 is hinged with the upper Hooke's joint 32, and the other end of the telescopic rod 33 is hinged with the lower Hooke's joint 34.

[0069] The curved surface polishing device provided by the application breaks through the limitation of traditional rigid contact polishing application, can realize real-time sensing of the polishing curved surface based on the dot matrix laser sensing sensor, the controller controls the telescopic rod to extend or retract in an online closed loop, ensures adaptive adjustment of the curved surface contact angle, improves the processing difficulty and poor quality of different positions and different curvatures of the curved surface in the traditional polishing mode, and has the versatility of multiple processing occasions, and improves the processing precision.

[0070] As Figure 4 shown, Figure 4 An optional flowchart of a curved surface polishing method provided by the embodiment of the application is shown, and the curved surface polishing method includes but is not limited to the following steps S10 to S40.

[0071] Step S10, three laser sensing sensors are selected from at least three laser sensing sensors, the projection points of the three laser sensing sensors on the surface of the workpiece to be processed are respectively obtained, and the projection distances of the laser sensing sensors and the surface of the workpiece to be processed are respectively calculated based on the respective projection points.

[0072] Step S20, a tool coordinate system is constructed according to the spatial positions of the three selected laser sensing sensors, and sensor position coordinates of the three laser sensing sensors in the tool coordinate system are determined.

[0073] Step S30, based on the three sensor position coordinates and the three projection distances, obtaining the light point position coordinates of the projection light points corresponding to the three laser sensing sensors in the tool coordinate system.

[0074] Step S40, obtaining the normal information of the to-be-ground curved surface region on the workpiece to be processed according to the three light point position coordinates, and controlling the hinge assembly to adjust the angle of the grinding wheel according to the normal information, so that the normal of the grinding wheel coincides with the normal of the to-be-ground curved surface region.

[0075] Step S50, when the normal of the grinding wheel coincides with the normal of the to-be-ground curved surface region, grinding the to-be-ground curved surface region according to the preset parameters.

[0076] Optionally, in the embodiment, as shown in Figure 5 , Figure 5 The laser sensing sensor and the corresponding projection light point position provided by the embodiment of the application are shown in the curved surface grinding device, which includes four laser sensing sensors, and the positions of the four laser sensing sensors are respectively denoted as E1, E2, E3 and E4. The corresponding projection light points on the workpiece to be processed are F l , F2, F3 and F4. The distances measured by the four laser sensing sensors between E1 and F l , E2 and F2, E3 and F3, and E4 and F4 are respectively h l , h2, h3 and h4. Three of the four laser sensing sensors can be selected for surface fitting to calculate the normal of the curved surface to-be-ground part of the curved surface workpiece to be processed.

[0077] Optionally, in the embodiment, three laser sensing sensors E1, E2 and E3 are selected as data sources for curved surface normal analysis. It is assumed that the plane formed by F l , F2 and F3 is F l , the normal vector of F l F2F3 is n', and the angle δ represents the included angle between the axis of the grinding wheel and the normal of the to-be-ground part of the workpiece to be processed. The normal of the grinding wheel coincides with the normal of the to-be-ground part of the curved surface workpiece to be processed, i.e., δ = 0°. It can be understood that it is difficult to achieve complete coincidence of the two normals, and therefore, in the embodiment, approximation is performed. When the angle δ is small enough and within a preset range, it is considered that the normal of the grinding wheel coincides with the normal of the to-be-ground part of the curved surface workpiece to be processed, so as to ensure that the accuracy meets the requirements.

[0078] In the embodiment, as shown in Figure 6 , Figure 6 ,The three selected laser sensing sensors and the corresponding projection point position diagram are shown in the tool coordinate system. According to the assembly relationship, the coordinates of the laser emission points of the three laser sensing sensors E1, E2 and E3 are E1(x1, y1, z1), E2(x2, y2, z2) and E3(x3, y3, z3) respectively.

[0079] In the present embodiment, the projection point F l In the coordinate plane of the tool coordinate system, the first projection point is denoted as F

[0080] Further, in an optional embodiment, the above-mentioned Figure 4 The step S30 includes but is not limited to the following steps S311 to S313.

[0081] Step S311: Obtain the first sensor position coordinates of the first laser sensing sensor in the tool coordinate system, and the first projection distance between the first laser sensing sensor and the first projection point.

[0082] Step S312: Obtain the first included angle between the laser ray emitted by the first laser sensing sensor and the polishing grinding wheel.

[0083] Step S313: Determine the light point position coordinates of the first projection point in the tool coordinate system according to the first sensor position coordinates, the first projection distance and the first included angle.

[0084] Specifically, as shown in Figure 7 , Figure 7 For Figure 6 The position diagram of the laser sensing sensor in the tool coordinate system is shown in the figure. The first sensor position coordinates E1(x1, y1, z1) of the first laser sensing sensor E1 in the tool coordinate system and the first projection distance h l from the first projection point are obtained; the first included angle θ between the laser ray emitted by the first laser sensing sensor and the polishing grinding wheel axis is obtained; the light point position coordinates of the first projection point in the tool coordinate system are determined according to the first sensor position coordinates E1(x1, y1, z1), the first projection distance h l and the first included angle θ.

[0085] In the present embodiment, it is assumed that the light point position coordinates of the first projection point are F l (x1', y1', z1'), then the light point position coordinates of the first projection point in the tool coordinate system are determined according to the first sensor position coordinates E1(x1, y1, z1), the first projection distance h l and the first included angle θ as follows:

[0086] x1′=h1cosθ, y1′=0, z1′=z1-h1sinθ

[0087] Furthermore, in an optional embodiment, the other two laser sensors are respectively designated as the second laser sensor E2 and the third laser sensor E3, and the corresponding projected light spots are respectively designated as the second projected light spot F2 and the third projected light spot F3. Figure 4 Step S30 also includes, but is not limited to, the following steps S321 to S323:

[0088] Step S321: Obtain the first laser beam intersection point between the first laser sensor and the second laser sensor, and the second laser beam intersection point between the first laser sensor and the third laser sensor.

[0089] Step S322: Calculate the second included angle between the first laser sensor, the second laser sensor and the intersection of the first laser beam, and calculate the third included angle between the first laser sensor, the third laser sensor and the intersection of the second laser beam.

[0090] Step S323: Obtain the second sensor position coordinates of the second laser sensing sensor in the tool coordinate system, and determine the light spot position coordinates of the second projection light point in the tool coordinate system based on the first sensor position coordinates, the second sensor position coordinates, and the second included angle.

[0091] In specific embodiments, the calculation process for projected light spot F2 and projected light spot F3 is similar; the calculation process for projected light spot F2 will be described here.

[0092] Specifically, such as Figure 8 As shown, Figure 8 for Figure 7 A schematic diagram showing the location of the extended intersection point of the laser sensing sensor, where E1F1 and E2F2 intersect at G. 12 The readings of the first laser sensor E1 and the second laser sensor E2 are H1 and H2, respectively, where H1 is the value from E1 to G. 12 The distance, H2, is from E2 to G. 12 The distance from E1 to E2 is l, and triangle E1E2G is given. 12 The three interior angles α, β, and γ are calculated as follows:

[0093]

[0094] According to triangle E1E2G 12 The length of F1F2 can be calculated as follows:

[0095]

[0096] likeFigure 9 As shown, Figure 9 For Figure 8 The structural diagram for calculating the projection light point position coordinates in the middle, in the E1E2F2F1 plane, F1F1' is perpendicular to E1E2, and intersects E1E2 at F1', F2F2' is perpendicular to E1E2 at F2', Perpendicular to the plane E1E2E3, Perpendicular to the plane E1E2E3, that is, parallel to the polishing wheel axis, from the geometric relationship, we can get:

[0097]

[0098] Let the coordinates of F1' and F2' be F1'(x1", y1", z1") and F2'(x2", y2", z2") respectively, then we have:

[0099]

[0100] The coordinates of F1' and F2' can be calculated as:

[0101]

[0102] From Figure 9 As shown, The angle between F2F2' and F2P2 is And The angle ε between F2F2' and F2P2,

[0103]

[0104] Then we have the following formula:

[0105]

[0106] (x1′-x2′,y2′-y2′,z2′-z2′)(x1-x2,y2-y2,z2-z2)=l(l-h1sinα-h2sinβ)

[0107] (x2′-x2″,y2′-y2″,z2′-z2″)(x1-x2,y2-y2,z1-z2)=0

[0108] By solving the above equations, the light point position coordinates (x2', y2', z2') of the projection light point F2 can be calculated.

[0109] Step S324: Obtain the third sensor position coordinates of the third laser sensor in the tool coordinate system, and determine the light point position coordinates of the third projection light point in the tool coordinate system according to the first sensor position coordinates, the third sensor position coordinates and the third included angle.

[0110] Similarly, the geometric relationship between the laser sensor E1 and the laser sensor E3 is established, and E1F1 and E3F3 intersect at point G. 13 The F3 coordinates (x3', y3', z3') can be obtained.

[0111] Further, in a possible implementation, the above Figure 4 Step 40 further includes but is not limited to the following steps S41-S42.

[0112] Step S41: Obtain the normal information of the curved surface area to be ground according to the three light point position coordinates, and determine the deflection direction of the grinding wheel according to the normal information.

[0113] Specifically, the F l , F2, F3 coordinates are (x1', y1', z1'), (x2', y2', z2'), and (x3', y3', z3'), respectively. According to the three point coordinates, the normal equation of the grinding area of the workpiece to be processed can be calculated as:

[0114]

[0115] It should be noted that the normal accurate positioning is to adjust the grinding wheel to be perpendicular to the surface of the grinding area of the workpiece to be processed. In specific implementation, since the grinding device is rigidly connected with the robot, adjusting the grinding device is equivalent to adjusting the robot posture. According to the actual normal of the surface of the grinding area of the workpiece calculated by the normal accurate positioning algorithm, the tool coordinate system is converted as shown in Figure 10 , Figure 10 is Figure 9 the structure diagram of the tool coordinate system conversion relationship in the embodiment, according to the normal information, the rotation relationship of the tool coordinate system before and after the accurate positioning (i.e. the deflection direction of the grinding wheel before and after) is determined, and then the parameters of the robot posture to be adjusted are obtained.

[0116] Step S42: According to the deflection direction, the extension lengths of the plurality of extension rods are calculated, and the extension lengths of the plurality of extension rods are controlled to adjust the angle of the grinding wheel so that the normal of the grinding wheel coincides with the normal of the curved surface area to be ground.

[0117] Specifically, the extension amount of each extension rod is calculated according to the deflection direction, and then the length of each extension rod is adjusted according to the extension amount of each extension rod, so that the angle of the grinding wheel can be adjusted to make the normal of the grinding wheel coincide with the normal of the curved surface area to be ground.

[0118] The extension rod can be driven by a motor or controlled by hydraulic pressure, so the extension rod can be controlled by a PWM signal or voltage to adjust the extension.

[0119] Further, in a possible implementation, the aboveFigure 4 Before step 50, the curved surface polishing method further comprises but is not limited to the following steps S60 to S90.

[0120] Step S60: Obtain normal information of the curved surface region to be polished after corresponding expansion of the plurality of expansion rods.

[0121] Specifically, after the expansion operation of the plurality of expansion rods, the geometric information of the curved surface region to be polished is recalculated according to the new positions of the plurality of expansion rods, and then the normal information of the curved surface region to be polished after corresponding expansion of the plurality of expansion rods is determined according to the geometric information of the curved surface region to be polished.

[0122] Step S70: Determine whether the polishing wheel is still deflected according to the normal information after corresponding expansion of the plurality of expansion rods.

[0123] Specifically, in an ideal case, the rotation axis of the polishing wheel should be perpendicular to the normal of the curved surface to be polished, that is, the normal vector of the polishing wheel should be aligned with the normal vector of the current curved surface region to be polished, and if there is an included angle between the two vectors, it means that the polishing wheel is deflected.

[0124] Step S80: If the polishing wheel is not deflected, determine that the normal of the polishing wheel coincides with the normal of the curved surface region to be polished.

[0125] Specifically, if the polishing wheel is not deflected, it is determined that the normal of the polishing wheel coincides with the normal of the curved surface region to be polished.

[0126] Step S90: If the polishing wheel is deflected, continue to adjust the expansion length of the expansion rod and re-determine whether the polishing wheel is still deflected until the polishing wheel is not deflected.

[0127] Specifically, if the polishing wheel is deflected, continue to adjust the expansion length of the expansion rod and re-determine whether the polishing wheel is still deflected until the polishing wheel is not deflected.

[0128] The embodiments described in the embodiments of the present application are used to more clearly illustrate the technical solutions of the embodiments of the present application, and do not constitute a limitation on the technical solutions provided by the embodiments of the present application. It is understood by those skilled in the art that with the evolution of technology and the appearance of new application scenarios, the technical solutions provided by the embodiments of the present application are also applicable to similar technical problems.

[0129] Those skilled in the art can understand that the technical solutions shown in the figures do not constitute a limitation on the embodiments of the present application, and can include more or fewer steps than shown in the figures, or combine certain steps, or different steps.

[0130] It is appreciated by those skilled in the art that all or some of the steps in the above disclosed method, the functional modules / units in the system, the device can be implemented as software, firmware, hardware or appropriate combination thereof.

[0131] The terms "first", "second", "third", "fourth" and the like in the description of the application and in the claims, if any, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the use of these terms is interchangeable under appropriate circumstances such that the embodiments of the application described herein are, for example, capable of orderly or sequential execution, even though a particular order is not described herein. Moreover, the terms "comprise", "have" and "include" and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, product or apparatus that comprises, has or includes a list of elements is not necessarily limited to those elements, but can include other elements not expressly listed or inherent to such process, method, system, product or apparatus.

[0132] It should be understood that, in the present application, "at least one" means one or more, and "multiple" means two or more. "And / or" is used to describe the relationship between associated objects, which means that there can be three relationships, for example, "A and / or B" can mean that there are three cases: only A, only B, and A and B at the same time, where A and B can be singular or plural. The character " / " generally represents an "or" relationship between the associated objects. "At least one of the following" or similar expressions means any combination of these items, including any combination of single or multiple items. For example, at least one of a, b or c can mean a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, and c can be singular or plural.

[0133] In several embodiments provided by the present application, it should be understood that the disclosed system and method can be implemented in other ways. For example, the above-described system embodiments are only illustrative, for example, the division of the above-mentioned units is only a logical functional division, and actual implementation can have another division manner, for example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the displayed or discussed each other can be indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

[0134] The units described as separate components above can or can not be physically separate, and the components displayed as units can or can not be physical units, i.e., can be located in one place, or can be distributed to multiple network units. Part or all of the units can be selected according to actual needs to achieve the purpose of the embodiment scheme.

[0135] In addition, each functional unit in each embodiment of the application can be integrated in one processing unit, or each unit can exist physically separately, or two or more units can be integrated in one unit. The integrated unit can be realized in the form of hardware or in the form of a software functional unit.

[0136] The preferred embodiments of the embodiments of the application are described above with reference to the accompanying drawings, and are not limited to the scope of the embodiments of the application. Any modification, equivalent replacement and improvement made by the skilled in the art without departing from the scope and essence of the embodiments of the application shall be within the scope of the embodiments of the application.

Claims

1. A method for polishing curved surfaces, characterized in that, include: First platform; The second platform is disposed opposite to the first platform, and the first platform and the second platform are fixedly connected based on at least three sets of hinge components; The second platform has a grinding wheel drive and an external controller on its surface near the first platform. The external controller is located above the grinding wheel drive. The second platform has at least three laser sensors and a grinding wheel on its surface away from the first platform. The laser sensors are located around the grinding wheel. The grinding wheel is used to grind the workpiece to be processed. The laser sensing sensor is used to perform active dot matrix data measurement and measure the distance between itself and the surface of the workpiece to be processed below in real time. The external controller is used to calculate the normal information of the curved surface area to be ground on the workpiece to be processed based on the distances obtained by each of the laser sensing sensors, and control the hinge assembly to adjust the angle of the grinding wheel based on the normal information so that the normal of the grinding wheel coincides with the normal of the curved surface area to be ground. The hinge assembly includes an upper Hooke hinge mounting base, an upper Hooke hinge, a telescopic rod, a lower Hooke hinge, and a lower Hooke hinge mounting base connected in sequence. The upper Hooke hinge mounting base is fixedly connected to the first platform, and the lower Hooke hinge mounting base is fixedly connected to the second platform. The edge of the first platform is provided with a plurality of first mounting protrusions adapted to the hinge assembly, and the first mounting protrusions are fixedly connected to the upper Hooke hinge mounting base. The edge of the second platform is provided with a plurality of second mounting protrusions adapted to the hinge assembly, and the second mounting protrusions are fixedly connected to the lower Hooke hinge mounting base. The telescopic rod is equipped with a linear motor driver, which is used to drive the telescopic rod to extend or compress. One end of the telescopic rod is hinged to the upper Hooke hinge, and the other end of the telescopic rod is hinged to the lower Hooke hinge. The control method is as follows: Three laser sensors are selected from at least three laser sensors, and the projection light spots of the three laser sensors on the surface of the workpiece to be processed are obtained respectively. The projection distance between the laser sensor and the surface of the workpiece to be processed is calculated based on each projection light spot. A tool coordinate system is constructed based on the spatial positions of the three selected laser sensors, and the sensor position coordinates of the three laser sensors in the tool coordinate system are determined respectively. Based on the position coordinates of the three sensors and the three projection distances, obtain the position coordinates of the projected light points corresponding to the three laser sensing sensors in the tool coordinate system; The normal information of the surface region to be ground on the workpiece is obtained based on the coordinates of the three light spots, and the hinge assembly is controlled to adjust the angle of the grinding wheel based on the normal information so that the normal of the grinding wheel coincides with the normal of the surface region to be ground. Obtain the normal information of the surface region to be ground after it has been extended and retracted by the corresponding extension rods. Based on the normal information after the extension and retraction of the multiple telescopic rods, determine whether the grinding wheel still has deflection; If the grinding wheel does not deflect, then the normal of the grinding wheel is determined to coincide with the normal of the surface area to be ground; If the grinding wheel is deflected, continue to adjust the extension length of the telescopic rod and re-determine whether the grinding wheel is still deflected, until the grinding wheel is no longer deflected; When the normal of the grinding wheel coincides with the normal of the surface area to be ground, the surface area to be ground is ground according to preset parameters.

2. The surface polishing method according to claim 1, characterized in that, Four sets of the hinge assemblies are provided between the first platform and the second platform, and four laser sensing sensors are provided on the surface of the second platform away from the first platform.

3. The surface polishing method according to claim 1, characterized in that, The coordinates of the three light spots are (x1′, y1′, z1′), (x2′, y2′, z2′), and (x3′, y3′, z3′). Based on these three coordinates, the normal equation of the area to be ground on the workpiece can be calculated as follows:

4. The surface polishing method according to claim 1, characterized in that, One of the projected light points lies in the coordinate plane of the tool coordinate system and is denoted as the first projected light point. The laser sensing sensor corresponding to the first projected light point is denoted as the first laser sensing sensor. The step of obtaining the position coordinates of the projected light points corresponding to the three laser sensors in the tool coordinate system based on the position coordinates of the three sensors and the three projection distances includes: Obtain the first sensor position coordinates of the first laser sensor in the tool coordinate system, and the first projection distance between the first laser sensor and the first projection light point; Obtain the first included angle between the laser beam emitted by the first laser sensor and the grinding wheel; The position coordinates of the first projected light point in the tool coordinate system are determined based on the position coordinates of the first sensor, the first projection distance, and the first included angle.

5. The surface polishing method according to claim 4, characterized in that, The other two laser sensors are referred to as the second laser sensor and the third laser sensor, respectively. The projection point corresponding to the second laser sensor is referred to as the second projection point, and the projection point corresponding to the third laser sensor is referred to as the third projection point. The step of obtaining the position coordinates of the projected light points corresponding to the three laser sensors in the tool coordinate system based on the position coordinates of the three sensors and the three projection distances further includes: Obtain the first laser beam intersection point between the first laser sensor and the second laser sensor, and the second laser beam intersection point between the first laser sensor and the third laser sensor; Calculate the second included angle between the first laser sensor, the second laser sensor, and the intersection point of the first laser beam; and calculate the third included angle between the first laser sensor, the third laser sensor, and the intersection point of the second laser beam. The second sensor position coordinates of the second laser sensing sensor in the tool coordinate system are obtained, and the position coordinates of the second projected light point in the tool coordinate system are determined according to the first sensor position coordinates, the second sensor position coordinates, and the second included angle. The third laser sensor position coordinates in the tool coordinate system are obtained, and the third projection light point position coordinates in the tool coordinate system are determined based on the first sensor position coordinates, the third sensor position coordinates, and the third included angle.

6. The surface polishing method according to claim 4, characterized in that, The position coordinates of the first projected light spot are F l (x1',y1',z1'), then based on the first sensor position coordinates E1(x1,y1,z1) and the first projection distance h l The coordinates of the first projected light spot in the tool coordinate system, determined by the first included angle θ, are as follows: x1′=h1cosθ, y1′=0, z1′=z1-h1sinθ.

7. The surface polishing method according to claim 1, characterized in that, The step of obtaining the normal information of the surface region to be ground on the workpiece based on the coordinates of the three light spots, and controlling the hinge assembly to adjust the angle of the grinding wheel based on the normal information so that the normal of the grinding wheel coincides with the normal of the surface region to be ground, includes: The normal information of the surface region to be ground is obtained based on the coordinates of the three light spots, and the deflection direction of the grinding wheel is determined based on the normal information. Based on the deflection direction, the telescopic lengths corresponding to the multiple telescopic rods are calculated, and the telescopic rods are controlled to extend and retract accordingly, so as to adjust the angle of the grinding wheel so that the normal of the grinding wheel coincides with the normal of the surface area to be ground.

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