A rigid-flexible coupling robot for polishing a complex curved surface

Abstract

This invention relates to a rigid-flexible coupling robot for grinding complex curved surfaces, comprising a frame, an adaptive grinding device, and a vibration damping device. The vibration damping device is fixed between a first moving platform and a second moving platform. The first moving platform is connected to the frame via a push rod moving device, and the second moving platform is connected to the adaptive grinding device via an electric push rod. The push rod moving device provides a downward thrust to the first moving platform to achieve contact between the adaptive grinding device and the workpiece to be ground. A first hoisting mechanism and a second hoisting mechanism respectively drive the retraction and extension of a position control flexible cable and an attitude adjustment flexible cable to achieve multi-degree-of-freedom movement of the adaptive grinding device within the frame. As can be seen from the above technical solution, the adaptive grinding device of this invention can automatically conform to complex surfaces to be processed, and has a large working space and accurate positioning.

Description

Technical Field

[0001] This invention relates to the field of grinding robots, and more specifically to a rigid-flexible coupled robot for grinding complex curved surfaces. Background Technology

[0002] Robotic grinding technology is a crucial manufacturing process in modern industry, widely used in metal processing, automotive manufacturing, aerospace, and electronic equipment. It improves production efficiency, reduces labor costs, and allows for automated, continuous operation in unmanned environments. However, in grinding applications involving large parts with numerous complex-shaped surfaces, the motion characteristics of the grinding robot and the structure of the actuators can lead to situations where certain surfaces cannot be ground or where grinding path planning becomes overly complex.

[0003] For example, the compliant grinding robot for curved workpieces described in application number "CN202310414147.4" uses eight independent flexible cables to drive the grinding actuator, enabling floating grinding of relatively smooth curved surfaces. However, the grinding actuator is relatively simple and difficult to grind more complex curved surfaces. The cable-driven structure cannot guarantee the stiffness required during the grinding process, and there is no corresponding flexible cable stiffness-changing tensioning mechanism. During the movement of the grinding actuator, the slack of the flexible cables can lead to inaccurate grinding positioning.

[0004] For example, the motion mechanism of a redundantly driven planar two-degree-of-freedom parallel grinding robot, as described in application number "CN202211332745.9", uses four movable links to redundantly drive the moving platform, which has good rigidity and can achieve two-degree-of-freedom grinding. However, when the surface shape of the workpiece to be ground is relatively complex, the moving platform with only two degrees of freedom is difficult to complete the grinding operation.

[0005] For example, a reconfigurable hybrid robot for grinding and polishing optical devices, as described in application number "CN202211537467.0", achieves high-rigidity and high-precision grinding by combining a lifting platform with a hybrid robotic arm structure. However, when the workpiece to be ground is large, the limited working space makes it difficult to reach certain surfaces, thus failing to meet the requirements of the grinding operation.

[0006] Therefore, in grinding operations involving larger components with complex surface shapes and high precision requirements, a grinding robot that can flexibly adapt to complex surfaces, has good rigidity, high precision, and a large working space is needed to enable grinding tasks to be carried out stably and efficiently. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art and provide a rigid-flexible coupling robot for grinding complex curved surfaces.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: including a frame, an adaptive grinding device suspended within the frame, and a shock-absorbing device connected to the adaptive grinding device. The shock-absorbing device is fixed between a first moving platform and a second moving platform. The first moving platform is connected to the frame via a push rod moving device. The second moving platform is connected to the adaptive grinding device via an electric push rod and is connected to a first winch mechanism via a position control flexible cable. The adaptive grinding device is connected to the second winch mechanism via an attitude adjustment flexible cable. The push rod moving device provides a downward thrust to the first moving platform to achieve contact between the adaptive grinding device and the workpiece to be ground. The first and second winch mechanisms respectively drive the retraction and extension of the position control flexible cable and the attitude adjustment flexible cable to achieve multi-degree-of-freedom movement of the adaptive grinding device within the frame.

[0009] The adaptive grinding device includes a grinding head connecting plate. A main grinding head and auxiliary grinding heads are provided on the lower surface of the grinding head connecting plate. The main grinding head is located at the center of the grinding head connecting plate, and multiple sets of auxiliary grinding heads are evenly arranged around the circumference of the main grinding head. The main grinding head includes, from top to bottom, a first elastic element, a first force sensor, a main grinding motor, and a main grinding wheel. The auxiliary grinding head includes, from top to bottom, a second elastic element, a second force sensor, an auxiliary grinding motor, and an auxiliary grinding wheel. The first and second elastic elements are respectively connected to the grinding head connecting plate. The first elastic element includes a vertical... The cylinder is perpendicular to the grinding head connecting plate and the main grinding head spring is placed inside the cylinder; the second elastic element includes a third connecting plate connected to the second force sensor, a slide rail connected to the grinding head connecting plate, a slider that forms a sliding fit with the slide rail, a connecting rod connecting the slider and the third connecting plate, a first telescopic guide rod connecting the third connecting plate and the grinding head connecting plate, and a secondary grinding head spring sleeved on the first telescopic guide rod. The main grinding wheel and the secondary grinding wheel form an inwardly concave circular curved surface in the initial state, and the main grinding wheel and the secondary grinding wheel realize the height change of their positions under the elastic action of the first elastic element and the second elastic element, respectively.

[0010] The shock absorption device includes a shock absorption top fixed to the first moving platform, a shock absorption base fixed to the second moving platform, a second telescopic guide rod connecting the shock absorption top and the shock absorption base, and a shock absorption spring sleeved on the second telescopic guide rod.

[0011] The push rod moving device includes a ball screw mechanism and a push rod assembly. The two ends of the push rod assembly are respectively hinged to the screw slider in the ball screw mechanism and the first moving platform. The ball screw mechanism is fixed on the frame.

[0012] The frame is generally square. A first beam and a second beam are connected to the top of the frame along the diagonal direction. The first beam and the second beam form an X-shaped top beam at the top of the frame. A U-shaped mounting beam is provided below the X-shaped top beam. A frame base plate is provided at the bottom of the frame. A grinding part placement platform is arranged parallel above the frame base plate. Casters are also installed at the bottom of the frame.

[0013] The cylinder body is a split structure, including a first cylinder body and a second cylinder body sleeved on the first cylinder body. The end of the first cylinder body is connected to a first force sensor through a first connecting plate, and the end of the second cylinder body is connected to a grinding head connecting plate through a second connecting plate. Four sets of fixed sliders are evenly arranged on the outer wall of the first cylinder body. The fixed sliders are located at the ends of the first cylinder body away from the first connecting plate. The second cylinder body is provided with a sliding groove that forms a sliding fit with the fixed sliders. The sliding groove is a blind groove opened from the end of the second connecting plate to the other end. A gap is left between the second cylinder body and the first cylinder body. A spring positioning seat fixed to the second connecting plate is provided inside the second cylinder body. One end of the main grinding head spring is located inside the first cylinder body and abuts against the first connecting plate. The other end of the main grinding head spring is located inside the second cylinder body and is sleeved on the spring positioning seat and abuts against the second connecting plate.

[0014] The slide rail is a hollow cuboid structure, formed by a first frame and a second frame arranged in parallel in the front-to-back direction, and a first side plate and a second side plate arranged in parallel in the left-to-right direction. The telescopic rod section of the first telescopic guide rod is hinged to the telescopic rod support, and the auxiliary grinding head spring is sleeved on the telescopic rod section of the first telescopic guide rod. The fixed rod section of the first telescopic guide rod passes between the first frame and the second frame and is fixed to the grinding head connecting plate. Two sets of sliders are provided, and the two sets of sliders are located in the inner frames of the first frame and the second frame, respectively, and form a sliding fit with the inner frames. Two sets of connecting rods are arranged in parallel, one end of each set of connecting rods is hinged to the connecting rod support, and the other end of each set of connecting rods is hinged to the end face of the two sets of sliders that are close to each other. The two sets of sliders are connected to the first side plate by tension springs. The telescopic rod support and the connecting rod support are symmetrically arranged along the circumference of the third connecting plate.

[0015] The push rod assembly includes a cylinder, a push rod that cooperates with the cylinder, and a push rod motor that drives the push rod to move. The cylinder is hinged to the ball screw slider in the ball screw mechanism via a Hooke hinge. The end of the push rod is provided with a first ball joint head, which cooperates with a first ball joint seat provided on the first moving platform.

[0016] The push rod moving device is provided in four sets. The four sets of ball screw mechanisms are fixed to the X-shaped top beam at the top of the frame by a base plate. The four sets of first ball joint seats are respectively set at the four corners of the first moving platform.

[0017] The telescopic section of the second telescopic guide rod is connected to the center of the shock-absorbing top seat, and the fixed section of the second telescopic guide rod is connected to the center of the shock-absorbing base. The shock-absorbing top seat and the shock-absorbing base are respectively provided with spring seats that cooperate with the ends of the shock-absorbing springs. The shock-absorbing device also includes a first energy storage spring and a second energy storage spring symmetrically arranged on both sides of the second telescopic guide rod. The first energy storage spring and the second energy storage spring are respectively connected to the shock-absorbing top seat and the shock-absorbing base. The axial directions of the first energy storage spring and the second energy storage spring are perpendicular to the axial direction of the shock-absorbing spring.

[0018] The shock-absorbing top seat includes a horizontally arranged first plate. Near both ends of the lower surface of the first plate, there are a second plate and a third plate perpendicular to the first plate. The ends of the second and third plates are bent inwards to form an inclined fourth plate and a fifth plate, respectively. The shock-absorbing base includes a horizontally arranged sixth plate. Near both ends of the upper surface of the sixth plate, there are a seventh plate and an eighth plate perpendicular to the sixth plate. The ends of the seventh and eighth plates are bent outwards to form an inclined ninth plate and a tenth plate, respectively. The second and third plates, the fourth and fifth plates, the seventh and eighth plates, and the ninth and tenth plates are all symmetrically arranged around a second telescopic guide rod. The fourth and ninth plates are parallel and are each fixed to a first energy storage spring. The fifth and tenth plates are parallel and are each fixed to a second energy storage spring, respectively.

[0019] One end of the position control cable is fixed to the drum in the first winch mechanism, and the other end of the position control cable passes through the first cable stiffness locking mechanism and the first pulley group in sequence before being fixed to the cable buckle on the second platform; one end of the attitude adjustment cable is fixed to the drum in the second winch mechanism, and the other end of the attitude adjustment cable passes through the second cable stiffness locking mechanism and the second pulley group in sequence before being hinged to the grinding head connecting plate in the adaptive grinding device; the upper surface of the grinding head connecting plate is provided with a second ball joint seat, and the end of the attitude adjustment cable is provided with a second ball joint head that cooperates with the second ball joint seat; the first pulley group includes a first pulley and a second pulley, and the second pulley group includes a third pulley, a fourth pulley, and a fifth pulley, all of which are rotatable casters;

[0020] The position control cable, attitude adjustment cable, first pulley group, second pulley group, cable buckle, and second ball joint seat are each provided in four sets. The four sets of first pulleys are respectively located at the middle of the four sides of the frame base plate, the four sets of second pulleys are respectively located at the middle of the four sides of the U-shaped mounting beam, the four sets of third pulleys are respectively located at the four corners of the frame base plate, the four sets of fourth pulleys are respectively located at the four corners of the U-shaped mounting beam, the four sets of fifth pulleys are respectively located at the four corners of the second moving platform, the four sets of cable buckles are respectively located at the middle of the four sides of the second moving platform, and the four sets of second ball joint seats are evenly distributed along the circumference of the grinding head connecting plate.

[0021] The first flexible cable variable stiffness locking mechanism and the second flexible cable variable stiffness locking mechanism have the same structure, both including a square variable stiffness base and a variable stiffness top plate, and each of the four corners of the variable stiffness base is provided with a column connected to the variable stiffness top plate.

[0022] The variable stiffness base and the variable stiffness top plate are provided with a sixth pulley, a seventh pulley, an eighth pulley and a ninth pulley, all with their axles arranged vertically. The seventh pulley and the eighth pulley are respectively fixed at both ends of the rotating pulley bracket, which is driven to rotate by a worm gear mechanism set on the variable stiffness base. The pulley supports of the sixth pulley and the ninth pulley are respectively fixed on two columns in a diagonal direction by elastic telescopic devices.

[0023] The elastic telescopic device includes a spring support fixed to the column, a third telescopic guide rod connecting the spring support and the pulley support, and a guide spring sleeved on the third telescopic guide rod. The telescopic rod end of the third telescopic guide rod is fixed to the pulley support, and the two ends of the guide spring abut against the pulley support and the spring support, respectively.

[0024] The worm gear mechanism includes a cylindrical shaft vertically disposed at the center of the variable stiffness base, a worm wheel mounted on the cylindrical shaft, a worm meshing with the worm wheel, and a worm stepper motor that drives the worm to rotate.

[0025] The rotating pulley bracket has a double-layer structure, including a first rectangular rod, a second rectangular rod, and a cylinder connecting the two. The bottom of the cylinder is mounted on a cylindrical shaft and is fixedly connected to a worm gear through a flange. A through groove is provided on the cylindrical surface of the cylinder for the position control cable or attitude adjustment cable to pass through.

[0026] The beneficial effects of this invention are as follows:

[0027] 1. The hybrid mechanism composed of the push rod moving device and the flexible cable in this invention can improve the robot's flexibility and large working space while providing sufficient grinding rigidity. It solves the problem that certain surfaces to be processed cannot be ground due to the constraint of joint movement in traditional robots, improves the insufficient rigidity of traditional flexible cable parallel robots in grinding, and improves the stability and safety of grinding operations.

[0028] 2. The first moving platform controlled by the push rod moving device and the second moving platform controlled by the position control flexible cable are connected by a shock absorption device, forming a rigid-flexible coupling structure, which can effectively reduce the adverse vibrations generated during grinding.

[0029] 3. The flexible cable variable stiffness locking mechanism can ensure that the flexible cable is always in a taut state during operation, effectively improving the positioning accuracy and response speed of the adaptive grinding device, and improving the problem of excessive cumulative error and low positioning accuracy of the existing grinding robot end effector.

[0030] 4. The adaptive grinding device can achieve adaptive fitting to complex surfaces to be processed, simplifying the motion trajectory planning of the grinding robot and effectively improving the efficiency and accuracy of grinding work.

[0031] 5. The combination of the electric push rod on the upper part of the adaptive grinding device and the four sets of attitude adjustment cables can realize the four-degree-of-freedom movement of the grinding device, further increasing the working space of the grinding robot and improving its working flexibility. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the structure of the present invention;

[0033] Figure 2 This is a schematic diagram of the framework of the present invention;

[0034] Figure 3 This is a schematic diagram of the hybrid drive structure of the position control flexible cable and push rod moving device of the present invention;

[0035] Figure 4 This is a schematic diagram of the connection structure of the position control flexible cable and the attitude adjustment flexible cable of the present invention;

[0036] Figure 5 This is a schematic diagram of the connection structure of the adaptive grinding device, shock absorption device, first moving platform, and second moving platform of the present invention. Figure 1 ;

[0037] Figure 6 This is a schematic diagram of the connection structure of the adaptive grinding device, shock absorption device, first moving platform, and second moving platform of the present invention. Figure 2 ;

[0038] Figure 7This is a schematic diagram of the adaptive polishing device of the present invention;

[0039] Figure 8 This is a schematic diagram of the main grinding head of the present invention;

[0040] Figure 9 yes Figure 8 A schematic diagram of the decomposed structure;

[0041] Figure 10 This is an exploded structural diagram of the cylinder and the main grinding head spring of the present invention. Figure 1 ;

[0042] Figure 11 This is an exploded structural diagram of the cylinder and the main grinding head spring of the present invention. Figure 2 ;

[0043] Figure 12 This is a schematic diagram of the structure of the auxiliary grinding head of the present invention;

[0044] Figure 13 yes Figure 12 Enlarged view of part A;

[0045] Figure 14 This is a schematic diagram of the slide rail in the auxiliary grinding head of the present invention;

[0046] Figure 15 This is a schematic diagram of the installation of the first mobile platform, the second mobile platform, and the shock absorption device of the present invention;

[0047] Figure 16 This is a schematic diagram of the structure of the shock absorption device of the present invention;

[0048] Figure 17 This is a schematic diagram of the push rod moving device of the present invention;

[0049] Figure 18 This is a schematic diagram of the structure of the first flexible cable variable stiffness locking mechanism of the present invention;

[0050] Figure 19 yes Figure 18 Enlarged view of part B;

[0051] Figure 20 This is a schematic diagram of the elastic telescopic device in the first flexible cable variable stiffness locking mechanism of the present invention.

[0052] The reference numerals in the above figures are as follows: Frame 1, First Beam 11, Second Beam 12, U-shaped Mounting Beam 13, Frame Base Plate 14, Grinding Part Placement Platform 15, Casters 16, Adaptive Grinding Device 2, Grinding Head Connecting Plate 21, Second Ball Joint Seat 211, Third Ball Joint Seat 212, Main Grinding Head 22, Main Grinding Wheel 221, Main Grinding Motor 222, First Force Sensor 223, Cylinder 224, First Cylinder 2241, Second Cylinder 2242, First Connecting Plate 2243, Second Connecting Plate 2244, Fixed Slider 2245, Slide 2246, Spring Positioning Seat 2247, Main Grinding Head Spring 225, Auxiliary Grinding Head 23 231, 232, 233, 234, 235, 2351, 2352, 2353, 2354, 236, 2361, 237, 2371, 238, 2381, 239, 230, 230, 231, 232, 235, 236, 236, 237, 238, 239, 230, 231, 311, 312, 313, 314, 315, 32, 321, 322, 330, 235, 2351, 2352, 2353, 2354, 236, 237, 238, 239, 230, 230, 231, 235, 2351, 2352, 2353, 2354, 235 ... Eighth plate 323, Ninth plate 324, Tenth plate 325, Second telescopic guide rod 33, Shock-absorbing spring 34, Spring seat 35, First energy storage spring 36, Second energy storage spring 37, First moving platform 41, First ball joint seat 411, Second moving platform 42, Flexible cable buckle 421, Electric push rod 43, Third ball joint head 431, Position control flexible cable 5, Push rod moving device 6, Ball screw mechanism 61, Screw slider 611, Screw slide rail 612, Ball screw 613, Screw motor 614, Motor bracket 615, Cylinder 62, Push rod 63, First ball joint head 631, Push rod motor 64, Hooke hinge 65, Base plate 66, Posture 7. Adjustable flexible cable, 71. Second ball joint, 8A. Variable stiffness locking mechanism of first flexible cable, 8B. Variable stiffness locking mechanism of second flexible cable, 81. Variable stiffness base, 811. Worm gear, 812. Worm stepper motor, 813. Variable stiffness top plate, 82. Column, 83. Sixth pulley, 84. Seventh pulley, 85. Eighth pulley, 86. Ninth pulley, 87. Rotary pulley bracket, 88. First rectangular rod, 881. Second rectangular rod, 882. Cylinder, 883. Spring support, 891. Pulley support, 892. Third telescopic guide rod, 893. Guide spring, 894. First pulley, 91. Second pulley, 92. Third pulley, 93. Fourth pulley, 94. Fifth pulley, 95. Detailed Implementation

[0053] The present invention will be further described below with reference to the accompanying drawings:

[0054] like Figure 1 , Figure 3 , Figure 4 , Figure 5 , Figure 6 The illustrated rigid-flexible coupling robot for grinding complex curved surfaces includes a frame 1, an adaptive grinding device 2 suspended within the frame 1, and a shock-absorbing device 3 connected to the adaptive grinding device 2. The shock-absorbing device 3 is fixed between a first moving platform 41 and a second moving platform 42. The first moving platform 41 is connected to the frame 1 via a push rod moving device 6, and the second moving platform 42 is connected to the adaptive grinding device 2 via an electric push rod 43. The second moving platform 42 is also connected to a first winch mechanism via a position control flexible cable 5. The adaptive grinding device 2 is connected to the second winch mechanism via an attitude adjustment flexible cable 7. The push rod moving device 6 provides a downward thrust to the first moving platform 41 to achieve contact between the adaptive grinding device 2 and the workpiece to be ground. The first and second winch mechanisms respectively drive the retraction and extension of the position control flexible cable 5 and the attitude adjustment flexible cable 7 to achieve multi-degree-of-freedom movement of the adaptive grinding device 2 within the frame 1.

[0055] Furthermore, such as Figure 2 As shown, the frame 1 is generally square. The top of the frame 1 is connected to the first beam 11 and the second beam 12 along the diagonal direction of the frame 1. The first beam 11 and the second beam 12 form the X-shaped top beam of the frame 1. The bottom of the X-shaped top beam is provided with the U-shaped mounting beam 13. The bottom of the frame 1 is provided with the frame base plate 14. The grinding part placement platform 15 is arranged parallel above the frame base plate 14. The bottom of the frame 1 is also equipped with casters 16.

[0056] Frame 1 is the largest area where the robot can move, and various components are mounted on the frame directly or indirectly in different ways. In this embodiment, frame 1 is constructed of aluminum profiles, and the profiles are connected by angle brackets, T-nuts, and hex bolts.

[0057] Furthermore, such as Figure 7 As shown, the adaptive grinding device 2 includes a grinding head connecting plate 21. The lower surface of the grinding head connecting plate 21 is provided with a main grinding head 22 and an auxiliary grinding head 23. The main grinding head 22 is located at the center of the grinding head connecting plate 21, and multiple sets of auxiliary grinding heads 23 are evenly arranged around the main grinding head 22.

[0058] Specifically, such as Figure 8 As shown, the main grinding head 22 includes a first elastic element, a first force sensor 223, a main grinding motor 222, and a main grinding wheel 221 arranged sequentially from top to bottom. Figure 12As shown, the auxiliary grinding head 23 includes a second elastic element, a second force sensor 233, an auxiliary grinding motor 232, and an auxiliary grinding wheel 231 arranged sequentially from top to bottom. Both the first and second elastic elements are connected to the grinding head connecting plate 21. The main grinding wheel 221 and the auxiliary grinding wheel 231 form an inwardly concave circular surface in their initial state, and their positions change height under the elastic action of the first and second elastic elements, respectively.

[0059] More specifically, such as Figure 8 , Figure 9 , Figure 10 , Figure 11 As shown, the first elastic element includes a cylindrical body 224 perpendicular to the grinding head connecting plate 21 and a main grinding head spring 225 placed inside the cylindrical body 224. The cylindrical body 224 is a split structure, including a first cylindrical body 2241 and a second cylindrical body 2242 sleeved on the first cylindrical body 2241. The first cylindrical body 2241, the second cylindrical body 2242, and the main grinding head spring 225 form an elastic mechanism that can achieve omnidirectional floating. The end of the first cylindrical body 2241 is connected to the first force sensor 223 through the first connecting plate 2243, and the end of the second cylindrical body 2242 is connected to the grinding head connecting plate 21 through the second connecting plate 2244. Four sets of fixed sliders 2245 are evenly arranged on the outer wall of the first cylindrical body 2241. The fixed sliders 2245 are located at the ends of the first cylindrical body 2241 away from the first connecting plate 2243. The second cylindrical body 2242 is provided with a sliding groove 2 that forms a sliding fit with the fixed sliders 2245. 246. The groove 2246 is a blind groove extending from one end of the second connecting plate 2244 to the other. A spring positioning seat 2247, fixed to the second connecting plate 2244, is provided inside the second cylinder 2242. One end of the main grinding head spring 225 is located inside the first cylinder 2241 and abuts against the first connecting plate 2243. The other end of the main grinding head spring 225 is located inside the second cylinder 2242 and is sleeved on the spring positioning seat 2247, abutting against the second connecting plate 2244. In this invention, a gap is left between the second cylinder 2242 and the first cylinder 2241; they are not tightly fitted. This allows the first cylinder 2241 to rotate slightly under the action of the main grinding head spring 225, thus achieving omnidirectional floating.

[0060] More specifically, such as Figure 12 , Figure 13 As shown, the second elastic element includes a third connecting plate 234 connected to the second force sensor 233, a slide rail 235 connected to the grinding head connecting plate 21, a slider 236 that slides with the slide rail 235, a connecting rod 237 connecting the slider 236 and the third connecting plate 234, a first telescopic guide rod 238 connecting the third connecting plate 234 and the grinding head connecting plate 21, and a secondary grinding head spring 239 sleeved on the first telescopic guide rod 238. Figure 14 As shown, the slide rail 235 is a hollow cuboid structure, consisting of a first frame 2351 and a second frame 2352 arranged in parallel in the front-to-back direction, and a first side plate 2353 and a second side plate 2354 arranged in parallel in the left-to-right direction. The telescopic rod section of the first telescopic guide rod 238 is hinged to the telescopic rod support 2381, and the auxiliary grinding head spring 239 is sleeved on the telescopic rod section of the first telescopic guide rod 238. The fixed rod section of the first telescopic guide rod 238 passes between the first frame 2351 and the second frame 2352 and is fixed to the grinding head connecting plate 21. Two sets of blocks 236 are provided. The two sets of sliders 236 are located in the inner frames of the first frame 2351 and the second frame 2352 respectively and form a sliding fit with the inner frames. Two sets of connecting rods 237 are arranged in parallel. One end of each set of connecting rods 237 is hinged to the connecting rod support 2371. The other end of each set of connecting rods 237 is hinged to the end face of the two sets of sliders 236 that are close to each other. The two sets of sliders 236 are connected to the first side plate 2353 by tension springs 2361 respectively. The telescopic rod support 2381 and the connecting rod support 2371 are symmetrically arranged along the circumference of the third connecting plate 234.

[0061] During operation, when the main grinding wheel 221 contacts the surface of the workpiece to be ground, the main grinding wheel 221 can float axially under the action of the main grinding head spring 225, achieving adaptive contact with the workpiece to be ground; when the main grinding wheel 221 no longer contacts the surface of the workpiece to be ground, the first cylinder 2241 and the second cylinder 2242 will return to their initial positions under the elastic restoring force of the main grinding head spring 225.

[0062] When the secondary grinding wheel 231 contacts the surface of the workpiece to be ground, under the combined action of the connecting rod 237, the slider 236, and the tension spring 2361, the slider 236 slides along the slide rail 235. Simultaneously, the first telescopic guide rod 238 and the secondary grinding head spring 239 are compressed under pressure, achieving adaptive contact between the secondary grinding head 23 and the surface of the workpiece. When the secondary grinding wheel 231 is no longer in contact with the surface of the workpiece, the slider 236 and the first telescopic guide rod 238 return to their initial positions under the elastic restoring force of the tension spring 2361 and the secondary grinding head spring 239, respectively.

[0063] In this embodiment, the main grinding head 22 is located at the center of the grinding head connecting plate 21, and six sets of auxiliary grinding heads 23 are evenly arranged circumferentially around the main grinding head 22. This arrangement utilizes the omnidirectional floating characteristic of the main grinding head 22 and the radial micro-rotation characteristics of the auxiliary grinding heads 23 to achieve adaptive fitting to parts with complex surfaces, simplifying the grinding path and improving grinding efficiency. Simultaneously, the first force sensor 223 arranged between the first cylinder 2241 and the main grinding motor 222, and the second force sensor 233 arranged between the third connecting plate 234 and the auxiliary grinding motor 232, can monitor the grinding pressure in real time for real-time control.

[0064] Furthermore, such as Figure 15 , Figure 16 As shown, the shock absorption device 3 includes a shock absorption top seat 31 fixed to the first moving platform 41, a shock absorption base 32 fixed to the second moving platform 42, a second telescopic guide rod 33 connecting the shock absorption top seat 31 and the shock absorption base 32, and a shock absorption spring 34 sleeved on the second telescopic guide rod 33. The shock absorption device 3 also includes a first energy storage spring 36 and a second energy storage spring 37 symmetrically arranged on both sides of the second telescopic guide rod 33. The first energy storage spring 36 and the second energy storage spring 37 are respectively connected to the shock absorption top seat 31 and the shock absorption base 32, and the axial directions of the first energy storage spring 36 and the second energy storage spring 37 are perpendicular to the axial direction of the shock absorption spring 34.

[0065] Specifically, the telescopic section of the second telescopic guide rod 33 is connected to the center of the shock-absorbing top seat 31, and the fixed section of the second telescopic guide rod 33 is connected to the center of the shock-absorbing base 32. The shock-absorbing top seat 31 and the shock-absorbing base 32 are respectively provided with spring seats 35 that cooperate with the end of the shock-absorbing spring 34.

[0066] More specifically, the damping top seat 31 resembles a π-shaped structure, including a horizontally arranged first plate 311. Near both ends of the lower surface of the first plate 311, there are second plates 312 and 313 perpendicular to the first plate 311. The ends of the second plates 312 and 313 are bent inwards to form inclined fourth plates 314 and fifth plates 315, respectively. The damping base 32 resembles an inverted π-shaped structure, including a horizontally arranged sixth plate 321. Near both ends of the upper surface of the sixth plate 321, there are seventh plates 322 and eighth plates perpendicular to the sixth plate 321. The ends of the seventh plate 322 and the eighth plate 323 are bent outward to form the inclined ninth plate 324 and tenth plate 325, respectively. The second plate 312 and the third plate 313, the fourth plate 314 and the fifth plate 315, the seventh plate 322 and the eighth plate 323, the ninth plate 324 and the tenth plate 325 are all symmetrically arranged with the second telescopic guide rod 33 as the center. The fourth plate 314 is parallel to the ninth plate 324 and both are fixed to the first energy storage spring 36, and the fifth plate 315 is parallel to the tenth plate 325 and both are fixed to the second energy storage spring 37.

[0067] In this invention, the first energy storage spring 36 and the second energy storage spring 37 have strong deformation capacity, good elastic recovery ability, and stable elastic force, which can effectively absorb the vibration and impact generated during the grinding process. The second telescopic guide rod 33 ensures that the shock absorption device 3 can only float along the axial direction, thereby ensuring that the first moving platform 41 and the second moving platform 42 only move relative to each other along the axial direction of the second telescopic guide rod 33. The compressed shock absorption spring 34 allows the shock absorption device 3 to quickly return to its original position when no force is applied. Therefore, the shock absorption device 3 can effectively reduce the adverse vibrations generated during the grinding process.

[0068] Furthermore, such as Figure 17 As shown, the push rod moving device 6 includes a ball screw mechanism 61 and a push rod assembly. The two ends of the push rod assembly are respectively hinged to the screw slider 611 in the ball screw mechanism 61 and the first moving platform 41. The ball screw mechanism 61 is fixed on the frame 1.

[0069] Specifically, the ball screw mechanism 61 includes a screw slide rail 612 fixed on the base plate 66, a screw slider 611 cooperating with the screw slide rail 612, a ball screw 613 cooperating with the screw slider 611, a screw motor 614 driving the ball screw 613 to rotate, and a motor bracket 615 fixing the screw motor 614. The push rod assembly includes a cylinder 62, a push rod 63 cooperating with the cylinder 62, and a push rod motor 64 driving the push rod 63 to move. The cylinder 62 is hinged to the screw slider 611 in the ball screw mechanism 61 via a Hooke joint 65. The end of the push rod 63 is provided with a first ball joint head 631, which cooperates with a first ball joint seat 411 provided on the first moving platform 41.

[0070] In this embodiment, the push rod moving device 6 is provided with four sets. The four sets of ball screw mechanisms 61 are respectively fixed to the X-shaped top beam at the top of the frame 1 through the base plate 66, that is, the four sets of base plates 66 are arranged in a star shape. The four sets of first ball joint seats 411 are respectively set at the four corners of the first moving platform 41. During operation, the screw motor 614 drives the ball screw 613 to rotate, which drives the screw slider 611 to move along the screw slide rail 612, thereby driving the push rod assembly to move. Then, the extension and retraction of the push rod 63 realizes the slight oscillation of the first moving platform 41 and provides downward working pressure to the main grinding head 22 and the auxiliary grinding head 23, so as to realize the grinding operation of the workpiece to be ground.

[0071] Furthermore, one end of the position control cable 5 is fixed to the drum in the first hoisting mechanism, and the other end of the position control cable 5 is fixed to the cable buckle 421 on the second moving platform 42 after passing through the first cable stiffness locking mechanism 8A and the first pulley group in sequence; one end of the attitude adjustment cable 7 is fixed to the drum in the second hoisting mechanism, and the other end of the attitude adjustment cable 7 is hinged to the grinding head connecting plate 21 in the adaptive grinding device 2 after passing through the second cable stiffness locking mechanism 8B and the second pulley group in sequence. That is, the first hoisting mechanism drives the second moving platform 42 to move within the working area defined by the frame 1 through the position control cable 5, and the second hoisting mechanism drives the adaptive grinding device 2 to achieve multi-degree-of-freedom rotation within the working area defined by the frame 1 through the attitude adjustment cable 7, which significantly improves the flexibility of the robot's work and increases the working space of the adaptive grinding device 2. Meanwhile, the first flexible cable variable stiffness locking mechanism 8A connected in series with the position control flexible cable 5 and the second flexible cable variable stiffness locking mechanism 8B connected in series with the attitude adjustment flexible cable 7 can keep the position control flexible cable 5 and the attitude adjustment flexible cable 7 in a taut state at all times, thereby improving the accuracy of robot positioning.

[0072] Furthermore, the second moving platform 42 is connected to the center of the adaptive grinding device 2 via an electric push rod 43. Specifically, a third ball joint head 431 is installed at the end of the electric push rod 43, and a third ball joint seat 212 that cooperates with the third ball joint head 431 is provided at the center of the upper surface of the grinding head connecting plate 21. Here, the stroke of the electric push rod 43 is relatively short, which can further increase the working space of the adaptive grinding device 2, and at the same time, it can further pre-tighten the attitude adjustment cable 7, effectively improving the accuracy and stability of the adaptive grinding device 2.

[0073] Furthermore, the first pulley group includes a first pulley 91 and a second pulley 92, and the second pulley group includes a third pulley 93, a fourth pulley 94, and a fifth pulley 95. All of the above pulleys are rotatable casters. The upper surface of the grinding head connecting plate 21 is provided with a second ball joint seat 211, and the end of the attitude adjustment flexible cable 7 is provided with a second ball joint head 71 that cooperates with the second ball joint seat 211.

[0074] In this embodiment, four sets of each are provided: position control cable 5, attitude adjustment cable 7, first pulley group, second pulley group, cable buckle 421, and second ball joint seat 211. The four sets of first pulleys 91 are respectively located at the center of the four sides of the frame base plate 14; the four sets of second pulleys 92 are respectively located at the center of the four sides of the U-shaped mounting beam 13; the four sets of third pulleys 93 are respectively located at the four corners of the frame base plate 14; the four sets of fourth pulleys 94 are respectively located at the four corners of the U-shaped mounting beam 13; the four sets of fifth pulleys 95 are respectively located at the four corners of the second moving platform 42; the four sets of cable buckles 421 are respectively located at the center of the four sides of the second moving platform 42; and the four sets of second ball joint seats 211 are evenly distributed along the circumference of the grinding head connecting plate 21. This arrangement reduces the space occupied by the entire adaptive grinding device 2 within the limited working area of ​​the frame 1, making the entire robot structure more compact and effectively improving the flexibility of the adaptive grinding device 2.

[0075] Furthermore, the first and second hoisting mechanisms have the same structure, each including a servo motor, reducer, coupling, drum, drum support, etc. For specific structures, please refer to the prior art, which will not be repeated here.

[0076] Furthermore, such as Figure 18 , Figure 19As shown, the first flexible cable variable stiffness locking mechanism 8A and the second flexible cable variable stiffness locking mechanism 8B have the same structure, both including a square variable stiffness base 81 and a variable stiffness top plate 82. The four corners of the variable stiffness base 81 are respectively provided with columns 83 connected to the variable stiffness top plate 82. Between the variable stiffness base 81 and the variable stiffness top plate 82 are arranged a sixth pulley 84, a seventh pulley 85, an eighth pulley 86, and a ninth pulley 87, all with their axles arranged vertically. The seventh pulley 85 and the eighth pulley 86 are respectively fixed to both ends of a rotating pulley bracket 88, which is driven to rotate by a worm gear mechanism mounted on the variable stiffness base 81. The pulley supports 892 of the sixth pulley 84 and the ninth pulley 87 are respectively fixed to two diagonally opposite columns 83 via elastic telescopic devices.

[0077] Specifically, such as Figure 20 As shown, the elastic telescopic device includes a spring support 891 fixed to the column 83, a third telescopic guide rod 893 connecting the spring support 891 and the pulley support 892, and a guide spring 894 sleeved on the third telescopic guide rod 893. The telescopic rod end of the third telescopic guide rod 893 is fixed to the pulley support 892, and the two ends of the guide spring 894 abut against the pulley support 892 and the spring support 891 respectively.

[0078] Specifically, the worm gear mechanism includes a cylindrical shaft vertically disposed at the center of the variable stiffness base 81, a worm wheel 811 mounted on the cylindrical shaft, a worm 812 meshing with the worm wheel 811, and a worm stepper motor 813 driving the worm 812 to rotate.

[0079] More specifically, the rotating pulley bracket 88 has a double-layer structure, including a first rectangular rod 881, a second rectangular rod 882 and a cylinder 883 connecting the two. The bottom of the cylinder 883 is mounted on a cylindrical shaft and the bottom is fixedly connected to the worm gear 811 through a flange. A through groove is provided on the cylindrical surface of the cylinder 883 for the position control cable 5 or the attitude adjustment cable 7 to pass through.

[0080] In this invention, the position control flexible cable 5 is connected as follows: one end of the position control flexible cable 5 is fixed to the drum in the first hoisting mechanism, and the other end of the position control flexible cable 5 passes sequentially through the ninth pulley 87, the eighth pulley 86, the seventh pulley 85, and the sixth pulley 84 in the first flexible cable variable stiffness locking mechanism 8A, then passes sequentially through the first pulley 91 and the second pulley 92 in the first pulley group, and finally is fixed to the flexible cable buckle on the second moving platform.

[0081] The attitude adjustment cable 7 is connected as follows: one end of the attitude adjustment cable 7 is fixed to the drum in the second hoisting mechanism, and the other end of the attitude adjustment cable 7 passes sequentially through the ninth pulley 87, the eighth pulley 86, the seventh pulley 85, and the sixth pulley 84 in the second cable stiffness locking mechanism 8B, and then passes sequentially through the third pulley 93, the fourth pulley 94, and the fifth pulley 95 in the second pulley group, and finally connects to the second ball joint seat 211 on the grinding head connecting plate 21.

[0082] The working principle of the first flexible cable variable stiffness locking mechanism 8A and the second flexible cable variable stiffness locking mechanism 8B is the same. The following explanation uses the first flexible cable variable stiffness locking mechanism 8A as an example. When the first flexible cable variable stiffness locking mechanism 8A needs to operate, the worm stepper motor 813 drives the worm 812 to rotate via a coupling, thereby driving the worm wheel 811 and the rotating pulley bracket 88 to rotate. This tightens the position control flexible cable 5 that cooperates with the first flexible cable variable stiffness locking mechanism 8A, keeping the position control flexible cable 5 always taut and preventing interference caused by cable slack during grinding. Furthermore, since the first flexible cable variable stiffness locking mechanism 8A uses a worm gear drive, which has a reverse stroke self-locking characteristic, the worm stepper motor 813 can remain de-energized during grinding operations. Meanwhile, due to the elastic characteristics of the guide spring 894, the pulley support 892 can float axially to a certain extent. This can effectively reduce the vibration of the position control cable 5, and also prevent the position control cable 5 from being too tight during operation, thus extending the service life of the position control cable 5.

[0083] The working principle and process of this invention are as follows:

[0084] First, the adaptive grinding device undergoes initial position adjustment. This is achieved by retracting and extending four sets of position control cables 5 through the forward and reverse rotation of four sets of first hoisting mechanism motors. The coordinated retraction and extension of these four sets of position control cables 5 drive the second moving platform 42 to move, thereby moving the adaptive grinding device 2 as a whole within the frame 1 to the initial grinding position. Simultaneously, the first moving platform 41, connected to the second moving platform 42 via a shock-absorbing device 3, follows the second moving platform 42 within the space along the X, Y, and Z axes under the action of four sets of push rod moving devices 6.

[0085] Secondly, the attitude of the adaptive grinding device is initially adjusted, that is, the four attitude adjustment cables 7 are wound up and down by the forward and reverse rotation of the four sets of second hoisting mechanism motors. The four sets of attitude adjustment cables 7 can drive the attitude adjustment of the adaptive grinding device 2 through the coordinated winding and unwinding. At the same time, the electric push rod 43 extends, so that the adaptive grinding device 2 fits the workpiece to be ground.

[0086] During the initial adjustment of position and attitude of the adaptive grinding device 2, the first flexible cable variable stiffness mechanism 8A and the second flexible cable variable stiffness mechanism 8B are always working, so that the position control flexible cable 5 and the attitude adjustment flexible cable 7 are in a taut state.

[0087] After the initial position and attitude adjustment is completed, the push rods in the four sets of push rod moving devices 6 are further extended, and the pressure is transmitted sequentially to the main grinding head 22 and the auxiliary grinding head 23 of the adaptive grinding device 2 through the first moving platform 41, the shock absorption device 3, the second moving platform 23 and the electric push rod 43. At the same time, the main grinding head 22 and the auxiliary grinding head are powered on to perform grinding operations on the area to be ground.

[0088] Finally, after completing the grinding operation on a certain area to be ground, the four sets of first hoisting mechanisms, the four sets of second hoisting mechanisms, and the four sets of push rod moving devices 6 work simultaneously to control the adaptive grinding device 2 to adjust its position and attitude, and continuously grind another area to be ground.

[0089] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A rigid-flexible coupled robot for polishing a complex curved surface, characterized in that: The system includes a frame (1), an adaptive grinding device (2) suspended within the frame (1), and a shock-absorbing device (3) connected to the adaptive grinding device (2). The shock-absorbing device (3) is fixed between a first moving platform (41) and a second moving platform (42). The first moving platform (41) is connected to the frame (1) via a push rod moving device (6), and the second moving platform (42) is connected to the adaptive grinding device (2) via an electric push rod (43). The position control cable (5) is connected to the first winch mechanism. The adaptive grinding device (2) is connected to the second winch mechanism through the attitude adjustment cable (7). The push rod moving device (6) provides a downward thrust to the first moving platform (41) to achieve the fit between the adaptive grinding device (2) and the workpiece to be ground. The first winch mechanism and the second winch mechanism drive the position control cable (5) and the attitude adjustment cable (7) to retract and extend to achieve the multi-degree-of-freedom movement of the adaptive grinding device (2) within the frame (1). The adaptive grinding device (2) includes a grinding head connecting plate (21). The lower surface of the grinding head connecting plate (21) is provided with a main grinding head (22) and a secondary grinding head (23). The main grinding head (22) is located at the center of the grinding head connecting plate (21), and multiple sets of secondary grinding heads (23) are evenly arranged around the main grinding head (22). The main grinding head (22) includes a first elastic element, a first force sensor (223), a main grinding motor (222), and a main grinding wheel (221) arranged sequentially from top to bottom. The secondary grinding head (23) includes a second elastic element, a second force sensor (233), a secondary grinding motor (232), and a secondary grinding wheel (231) arranged sequentially from top to bottom. The first elastic element and the second elastic element are respectively connected to the grinding head connecting plate (21). The first elastic element includes a part perpendicular to the grinding head connecting plate (21). The cylinder (224) and the main grinding head spring (225) placed inside the cylinder (224); the second elastic element includes a third connecting plate (234) connected to the second force sensor (233), a slide rail (235) connected to the grinding head connecting plate (21), a slider (236) that forms a sliding fit with the slide rail (235), a connecting rod (237) connecting the slider (236) and the third connecting plate (234), a first telescopic guide rod (238) connecting the third connecting plate (234) and the grinding head connecting plate (21), and a secondary grinding head spring (239) sleeved on the first telescopic guide rod (238). The main grinding wheel (221) and the secondary grinding wheel (231) form an inwardly concave circular curved surface in the initial state, and the main grinding wheel (221) and the secondary grinding wheel (231) realize the height change of their positions under the elastic action of the first elastic element and the second elastic element, respectively. The shock absorption device (3) includes a shock absorption top seat (31) fixed to the first moving platform (41), a shock absorption base (32) fixed to the second moving platform (42), a second telescopic guide rod (33) connecting the shock absorption top seat (31) and the shock absorption base (32), and a shock absorption spring (34) sleeved on the second telescopic guide rod (33). The push rod moving device (6) includes a ball screw mechanism (61) and a push rod assembly. The two ends of the push rod assembly are respectively hinged to the screw slider (611) in the ball screw mechanism (61) and the first moving platform (41). The ball screw mechanism (61) is fixed on the frame (1).

2. The rigid-flexible coupled robot for polishing complex curved surfaces according to claim 1, wherein: The frame (1) is square in shape. The top of the frame (1) is connected to a first beam (11) and a second beam (12) along the diagonal direction of the frame (1). The first beam (11) and the second beam (12) form an X-shaped top beam at the top of the frame (1). A square mounting beam (13) is provided below the X-shaped top beam. The bottom of the frame (1) is provided with a frame base plate (14). A grinding part placement platform (15) is arranged parallel above the frame base plate (14). Casters (16) are also installed at the bottom of the frame (1).

3. The rigid-flexible coupled robot for polishing complex curved surfaces according to claim 1, wherein: The cylinder (224) is a split structure, including a first cylinder (2241) and a second cylinder (2242) sleeved on the first cylinder (2241). The end of the first cylinder (2241) is connected to the first force sensor (223) through a first connecting plate (2243), and the end of the second cylinder (2242) is connected to the grinding head connecting plate (21) through a second connecting plate (2244). Four sets of fixed sliders (2245) are evenly arranged on the outer wall of the first cylinder (2241). The fixed sliders (2245) are located at the end of the first cylinder (2241) away from the first connecting plate (2243). The second cylinder (2242) is provided with a connection to the fixed sliders (2243). 45) A sliding groove (2246) is formed to form a sliding fit. The sliding groove (2246) is a blind groove opened from the second connecting plate (2244) end to the other end. A gap is left between the second cylinder (2242) and the first cylinder (2241). A spring positioning seat (2247) fixed to the second connecting plate (2244) is provided in the second cylinder (2242). One end of the main grinding head spring (225) is located in the first cylinder (2241) and abuts against the first connecting plate (2243). The other end of the main grinding head spring (225) is located in the second cylinder (2242) and is sleeved on the spring positioning seat (2247) and abuts against the second connecting plate (2244).

4. The rigid-flexible coupled robot for polishing complex curved surfaces according to claim 1, wherein: The slide rail (235) is a hollow cuboid structure, consisting of a first frame (2351) and a second frame (2352) arranged in parallel front-to-back direction, and a first side plate (2353) and a second side plate (2354) arranged in parallel left-to-right direction. The telescopic rod section of the first telescopic guide rod (238) is hinged to the telescopic rod support (2381), and the auxiliary grinding head spring (239) is sleeved on the telescopic rod section of the first telescopic guide rod (238). The fixed rod section of the first telescopic guide rod (238) passes between the first frame (2351) and the second frame (2352) and is fixed to the grinding head connecting plate (21); the slider ( 236) Two sets of sliders (236) are set up, and the two sets of sliders (236) are located in the inner frames of the first frame (2351) and the second frame (2352) respectively and form a sliding fit with the inner frame respectively; the two sets of connecting rods (237) are arranged in parallel, one end of the two sets of connecting rods (237) is hinged to the connecting rod support (2371), and the other end of the two sets of connecting rods (237) is hinged to the end face of the two sets of sliders (236) respectively. The two sets of sliders (236) are connected to the first side plate (2353) respectively by tension springs (2361). The telescopic rod support (2381) and the connecting rod support (2371) are symmetrically arranged along the circumference of the third connecting plate (234).

5. The rigid-flexible coupled robot for polishing complex curved surfaces according to claim 1, wherein: The push rod assembly includes a cylinder (62), a push rod (63) that cooperates with the cylinder (62), and a push rod motor (64) that drives the push rod (63) to move. The cylinder (62) is hinged to the ball screw slider (611) in the ball screw mechanism (61) through a Hooke hinge (65). The end of the push rod (63) is provided with a first ball joint head (631), which cooperates with a first ball joint seat (411) provided on the first moving platform (41). The push rod moving device (6) is provided in four sets. The four sets of ball screw mechanisms (61) are fixed on the X-shaped top beam at the top of the frame (1) by the base plate (66) respectively. The four sets of first ball joint seats (411) are respectively set at the four corners of the first moving platform (41).

6. The rigid-flexible coupled robot for polishing complex curved surfaces according to claim 1, wherein: The telescopic section of the second telescopic guide rod (33) is connected to the center of the shock-absorbing top seat (31), and the fixed section of the second telescopic guide rod (33) is connected to the center of the shock-absorbing base (32). The shock-absorbing top seat (31) and the shock-absorbing base (32) are respectively provided with spring seats (35) that cooperate with the end of the shock-absorbing spring (34). The shock-absorbing device (3) also includes a first energy storage spring (36) and a second energy storage spring (37) symmetrically arranged on both sides of the second telescopic guide rod (33). The first energy storage spring (36) and the second energy storage spring (37) are respectively connected to the shock-absorbing top seat (31) and the shock-absorbing base (32). The axial direction of the first energy storage spring (36) and the second energy storage spring (37) is perpendicular to the axial direction of the shock-absorbing spring (34).

7. The rigid-flexible coupled robot for polishing complex curved surfaces according to claim 6, characterized in that: The shock-absorbing top seat (31) includes a horizontally arranged first plate (311). The lower surface of the first plate (311) has a second plate (312) and a third plate (313) perpendicular to the first plate (311) near both ends. The ends of the second plate (312) and the third plate (313) are respectively bent inward to form an inclined fourth plate (314) and a fifth plate (315). The shock-absorbing base (32) includes a horizontally arranged sixth plate (321). The upper surface of the sixth plate (321) has a seventh plate (322) and an eighth plate (323) perpendicular to the sixth plate (321) near both ends. The seventh plate (322)... The ends of the second plate (312) and the third plate (313), the fourth plate (314) and the fifth plate (315), the seventh plate (322) and the eighth plate (323), the ninth plate (324) and the tenth plate (325) are bent outward to form the inclined ninth plate (324) and the tenth plate (325). The second plate (312) and the third plate (313), the fourth plate (314) and the ninth plate (324) are symmetrically arranged with the second telescopic guide rod (33) as the center. The fourth plate (314) and the ninth plate (324) are parallel and both are fixed to the first energy storage spring (36). The fifth plate (315) and the tenth plate (325) are parallel and both are fixed to the second energy storage spring (37).

8. The rigid-flexible coupled robot for polishing complex curved surfaces according to claim 1, wherein: One end of the position control cable (5) is fixed to the drum in the first winch mechanism, and the other end of the position control cable (5) is fixed to the cable buckle (421) on the second moving platform (42) after passing through the first cable stiffness locking mechanism (8A) and the first pulley group in sequence; one end of the attitude adjustment cable (7) is fixed to the drum in the second winch mechanism, and the other end of the attitude adjustment cable (7) is fixed to the adaptive grinding device after passing through the second cable stiffness locking mechanism (8B) and the second pulley group in sequence. The grinding head connecting plate (21) in the setting (2) is hinged, and the upper plate surface of the grinding head connecting plate (21) is provided with a second ball joint seat (211). The end of the attitude adjustment flexible cable (7) is provided with a second ball joint head (71) that cooperates with the second ball joint seat (211). The first pulley group includes a first pulley (91) and a second pulley (92). The second pulley group includes a third pulley (93), a fourth pulley (94) and a fifth pulley (95). All of the above pulleys are rotatable universal wheels. The position control cable (5), attitude adjustment cable (7), first pulley group, second pulley group, cable buckle (421), and second ball joint seat (211) are each provided in four groups. The four groups of first pulleys (91) are respectively located at the middle of the four sides of the frame base plate (14), the four groups of second pulleys (92) are respectively located at the middle of the four sides of the U-shaped mounting beam (13), the four groups of third pulleys (93) are respectively located at the four corners of the frame base plate (14), the four groups of fourth pulleys (94) are respectively located at the four corners of the U-shaped mounting beam (13), the four groups of fifth pulleys (95) are respectively located at the four corners of the second moving platform (42), the four groups of cable buckles (421) are respectively located at the middle of the four sides of the second moving platform (42), and the four groups of second ball joint seats (211) are evenly distributed along the circumference of the grinding head connecting plate (21).

9. The rigid-flexible coupled robot for polishing complex curved surfaces according to claim 8, characterized in that: The first flexible cable variable stiffness locking mechanism (8A) and the second flexible cable variable stiffness locking mechanism (8B) have the same structure, each including a square variable stiffness base (81) and a variable stiffness top plate (82). The four corners of the variable stiffness base (81) are respectively provided with columns (83) connected to the variable stiffness top plate (82). The variable stiffness base (81) and the variable stiffness top plate (82) are provided with a sixth pulley (84), a seventh pulley (85), an eighth pulley (86) and a ninth pulley (87) with their axles arranged vertically. The seventh pulley (85) and the eighth pulley (86) are respectively fixed at both ends of the rotating pulley bracket (88). The rotating pulley bracket (88) is driven to rotate by a worm gear mechanism set on the variable stiffness base (81). The pulley supports (892) of the sixth pulley (84) and the ninth pulley (87) are respectively fixed on two columns (83) in the diagonal direction by elastic telescopic devices. The elastic telescopic device includes a spring support (891) fixed to the column (83), a third telescopic guide rod (893) connecting the spring support (891) and the pulley support (892), and a guide spring (894) sleeved on the third telescopic guide rod (893). The telescopic rod end of the third telescopic guide rod (893) is fixed to the pulley support (892), and the two ends of the guide spring (894) abut against the pulley support (892) and the spring support (891) respectively.

10. The rigid-flexible coupled robot for polishing complex curved surfaces according to claim 9, characterized in that: The worm gear mechanism includes a cylindrical shaft vertically disposed at the center of the variable stiffness base (81), a worm wheel (811) mounted on the cylindrical shaft, a worm (812) meshing with the worm wheel (811), and a worm stepper motor (813) that drives the worm (812) to rotate. The rotating pulley bracket (88) is a double-layer structure, including a first rectangular rod (881), a second rectangular rod (882) and a cylinder (883) connecting the two. The bottom of the cylinder (883) is mounted on a cylindrical shaft and the bottom is fixedly connected to the worm gear (811) through a flange. The cylindrical surface of the cylinder (883) is provided with a through groove for the position control cable (5) or attitude adjustment cable (7) to pass through.

Images