An automatic spraying device and spraying method for long and narrow curved surface space

Abstract

This invention discloses an automatic spraying device and method for narrow curved surfaces, belonging to the technical field of automatic spraying. Using the central axis of the narrow curved surface as a reference, a crankshaft track is established inside the space. A flexible traction device drives a spraying carriage to move smoothly along the crankshaft track. Simultaneously, a circumferential rotation mechanism on the spraying carriage drives the spray gun to rotate circumferentially, and a radial linear movement mechanism on the carriage drives the spray gun to translate radially. Combined with the movement of the spraying carriage itself, the spray gun moves accurately along a predetermined path, thereby enabling accurate and efficient spraying of the narrow curved surface and simplifying the control of the spray gun's posture.

Description

Technical Field

[0001] This invention belongs to the technical field of automatic spraying, specifically relating to an automatic spraying device and method for narrow curved surfaces. Background Technology

[0002] When spraying paint onto the narrow curved space inside a curved shell with a large aspect ratio, the existing technology mainly uses the following two spraying methods:

[0003] The first method involves manually inserting the spray gun into the narrow, curved space and controlling the spray gun to perform the spraying. However, since it is difficult to obtain a clear view inside the narrow space and the spraying depends on the skill level of the operator, it is difficult to guarantee the consistency of the spraying quality inside the narrow, curved space.

[0004] The second method involves using a robotic arm to guide the spray gun into a narrow, curved space. The robotic arm moves and rotates the spray gun linearly according to predetermined actions, thus spraying the interior of the narrow, curved space. Compared to manual operation, the robotic arm can more precisely control the spray gun's posture. However, when dealing with parts with complex internal shapes and large length-to-diameter ratios, the robotic arm struggles to penetrate the narrow, curved space, resulting in a limited spraying area and a tendency to interfere with the parts during the spraying process.

[0005] Therefore, in view of the above-mentioned shortcomings in the existing technology for spraying inside narrow curved spaces, the present invention discloses an automatic spraying device and spraying method for narrow curved spaces. Summary of the Invention

[0006] This invention discloses an automatic spraying device and spraying method for narrow curved surfaces, which can ensure that the spray gun moves strictly according to the predetermined movement path, thereby performing accurate and efficient spraying operations on the narrow curved surface, and will not interfere with the parts during the spraying process.

[0007] This invention is achieved through the following technical solution:

[0008] An automatic spraying device for a narrow, curved surface includes a crankshaft track adapted to the central axis of the narrow, curved surface. A spraying carriage is fitted around the outside of the crankshaft track. Both ends of the spraying carriage are provided with swing guides that slide and conform to the surface of the crankshaft track. An attitude adjuster is provided outside the spraying carriage, which can rotate circumferentially and move radially relative to the inner surface contour of the narrow, curved surface. A spray gun is provided on the actuating end of the attitude adjuster. A flexible traction device is provided outside the crankshaft track. The traction end of the flexible traction device is connected to the spraying carriage, and the traction end of the flexible traction device always conforms to the crankshaft track during traction.

[0009] To better realize the present invention, the attitude adjuster further includes a circumferential rotation mechanism and a radial linear movement mechanism. The circumferential rotation mechanism is coaxially rotatably sleeved on the outside of the spraying carriage. The radial linear movement mechanism is provided on the rotating end of the circumferential rotation mechanism, and a spray gun is provided on the moving end of the radial linear movement mechanism.

[0010] To better realize the present invention, the circumferential rotary mechanism further includes a rotary fixed bracket, a rotary bearing, a rotary frame, and a rotary drive mechanism. The rotary fixed bracket is fixedly installed on the outside of the painting cart. The rotary bearing is coaxially arranged inside the rotary fixed bracket, and the rotary drive mechanism is arranged on the rotary fixed bracket. The rotary frame is rotatably installed inside the rotary bearing, and the rotary frame is provided with a radial linear movement mechanism. The rotary drive mechanism is used to drive the rotary frame to rotate circumferentially.

[0011] To better realize the present invention, the radial linear movement mechanism further includes a radial fixed bracket, a slide rail, a slider, and a linear drive mechanism. The radial fixed bracket is fixedly installed on the rotary frame. The slide rail and the linear drive mechanism are provided on the radial fixed bracket. The slider is slidably installed on the slide rail. A spray gun is installed on the slider. The drive end of the linear drive mechanism is connected to one side of the slider.

[0012] To better realize the present invention, a counterweight adjustment part is further provided on the rotary frame on the opposite side of the radial linear movement mechanism.

[0013] To better realize the present invention, the swing guide part further includes a guide frame, support rollers, and ball joints. The guide frame is sleeved on the outside of the crankshaft track. The opposite sides of the guide frame are connected to the ends of the spraying carriage through ball joints. A plurality of support rollers are rotatably arranged on the inner wall of the guide frame. The support rollers are in rolling contact with the outer surface of the crankshaft track.

[0014] To better realize the present invention, the flexible traction device further includes a flexible traction rope, a traction wheel, and a traction wheel drive mechanism. A traction groove is provided on the side wall of the crankshaft track. Traction wheels are rotatably installed at both ends of the traction groove. A flexible traction rope is wound between the traction wheels at both ends. The flexible traction rope is connected to the spraying trolley. The traction wheel is connected to the traction wheel drive mechanism for transmission.

[0015] An automated spraying method for narrow, curved surfaces, based on an automated spraying device, includes the following steps:

[0016] Step 1: Using the central axis of the narrow curved surface as a reference, set up a crankshaft track inside the narrow curved surface, and install a spraying trolley and a flexible traction device on the outside of the crankshaft track.

[0017] Step 2: Install the attitude adjuster at the calibrated position on the outside of the spraying carriage, and control the attitude adjuster to move to the zero position. Install the spray gun at the calibrated position on the attitude adjuster.

[0018] Step 3: Plan the motion trajectory of the spray gun according to the shape of the inner surface of the narrow curved surface. Use a flexible traction device to pull the spraying carriage along the crankshaft track. During the traction process, the attitude adjuster drives the spray gun to rotate circumferentially and move radially, so that the spray gun moves along the planned motion trajectory to complete the spraying of the narrow curved surface.

[0019] Furthermore, step 1 includes:

[0020] Step 1.1, Offline trajectory programming design: Based on the theoretical narrow curved surface model, the motion trajectory of the spraying cart under theoretical conditions is obtained through simulation; the motion trajectory of the spraying cart is extracted to design the theoretical central crankshaft, and the crankshaft track is designed with the theoretical central axis of the theoretical narrow curved surface model;

[0021] Step 1.2: Based on the theoretical narrow curved surface model, establish a spatial coordinate system, select external measurable positions on the theoretical narrow curved surface model, and arrange multiple first-type feature points along the axial and circumferential directions, and extract the first theoretical coordinates of the first-type feature points; select external measurable positions on the crankshaft track and arrange multiple second-type feature points along the axial and circumferential directions, and extract the second theoretical coordinates of the second-type feature points.

[0022] Step 1.3: Based on the theoretical central axis, several segmented arc-shaped track modules are embedded into the narrow curved surface space and pre-assembled to form the crankshaft track;

[0023] Step 1.4: Establish a world coordinate system, measure the first actual coordinates of the first type of feature points and the second actual coordinates of the second type of feature points in the world coordinate system; calculate the position transformation matrix between the spatial coordinate system and the world coordinate system based on the difference between the first theoretical coordinates and the first actual coordinates.

[0024] Step 1.5: Based on the position transformation matrix, transform the second type of feature points on the crankshaft track from the world coordinate system to the spatial coordinate system to obtain the second transformed coordinates of the second feature points;

[0025] Step 1.6: Calculate the deviation representation between the second theoretical coordinates and the second transformed coordinates, and adjust the pose of each segmented arc track module based on the deviation vector until the deviation representation between the second theoretical coordinates and the second transformed coordinates meets the standard.

[0026] Step 1.7: Fix each segmented arc track module, and install the spraying trolley and flexible traction device on the outside of the formed crankshaft track.

[0027] Furthermore, the deviation representation quantity includes the deviation vector ΔP between the second theoretical coordinates and the second transformed coordinates. i When ||△P i ||≤±5mm is used to determine whether the deviation meets the standard.

[0028] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0029] This invention uses the central axis of a narrow, curved surface as a reference, establishes a crankshaft track inside the narrow, curved surface, and drives the spraying carriage to move smoothly along the crankshaft track through a flexible traction device. At the same time, the spray gun rotates circumferentially through the circumferential rotation mechanism on the spraying carriage, and the spray gun translates radially through the radial linear movement mechanism on the spraying carriage. Combined with the movement of the spraying carriage itself, the spray gun moves accurately along the predetermined motion path, thereby enabling accurate and efficient spraying of the narrow, curved surface and simplifying the difficulty of controlling the spray gun's posture. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of an automatic spraying device;

[0031] Figure 2 This is a schematic diagram of a circumferential rotary mechanism and a radial linear motion mechanism;

[0032] Figure 3 This is a schematic diagram of the swing guide section;

[0033] Figure 4 This is a schematic diagram of the circumferential rotary mechanism;

[0034] Figure 5 This is a schematic diagram of the radial linear motion mechanism;

[0035] Figure 6 This is a schematic diagram of the flexible traction device.

[0036] Figure 7 This is a schematic diagram of the embedded splicing of segmented arc-shaped track modules;

[0037] Figure 8 This is a schematic diagram of the curved space and crankshaft track arrangement;

[0038] Figure 9 A schematic diagram of the adjustable support unit for the crankshaft track.

[0039] Figure 10 A schematic diagram showing the working of the adjustment tool and screw sleeve.

[0040] Wherein: 100-Spraying trolley; 200-Crankshaft track; 300-Flexible traction device; 400-Spray gun; 101-Chassis body; 102-Support roller; 103-Spherical hinge; 104-Circumferential rotation mechanism; 105-Radial linear movement mechanism; 106-Counterweight adjustment unit; 201-Segmented arc track module; 202-Positioning pin; 203-Fasting bolt; 204-Adjustable support unit; 205-Adjusting tool rod; 301-Flexible traction rope; 302-Traction wheel; 303-Traction wheel drive mechanism; 1041-Slewing fixed bracket; 1042-Slewing bearing; 1043-Slewing frame; 1044-Slewing drive mechanism; 1051-Radial fixed bracket; 1052-Slide rail; 1053-Slider; 1054-Linear drive mechanism; 2041-Adjustable screw; 2042-Screw sleeve; 2043-Locking nut; 2044-Foot. Detailed Implementation

[0041] Example 1:

[0042] This embodiment provides an automatic spraying device for narrow, curved surfaces, such as... Figure 1 and Figure 2 As shown, the system includes a crankshaft track 200 adapted to the central axis of a narrow curved surface space. A spraying carriage 100 is fitted around the outside of the crankshaft track 200. Both ends of the spraying carriage 100 are provided with swing guides that slide and conform to the surface of the crankshaft track 200. An attitude adjuster is provided on the outside of the spraying carriage 100, which can rotate circumferentially and move radially relative to the inner surface contour of the narrow curved surface space. A spray gun 400 is provided on the actuating end of the attitude adjuster. A flexible traction device 300 is provided on the outside of the crankshaft track 200. The traction end of the flexible traction device 300 is connected to the spraying carriage 100. The traction end of the flexible traction device 300 always conforms closely to the crankshaft track 200 during the traction process.

[0043] A crankshaft track 200 is constructed inside a narrow, curved surface space, such that the central axis of the crankshaft track 200 coincides with the central axis of the narrow, curved surface space. This coincidence is considered complete if the positional deviation between the central axis of the crankshaft track 200 and the central axis of the narrow, curved surface space meets the calibration range. The front and rear ends of the painting carriage 100 are slidably fitted onto the outside of the crankshaft track 200 via swing guides. During the process of the painting carriage 100 being pulled by the flexible traction device 300, the swing guides remain in constant contact with the outer surface of the crankshaft track 200, thus ensuring that the painting carriage 100 moves smoothly along the crankshaft track 200.

[0044] During the movement of the painting carriage 100, the attitude adjuster drives the spray gun 400 to rotate circumferentially and move radially linearly. This, in conjunction with the movement of the painting carriage 100 along the crankshaft track 200, allows the spray gun 400 to spray the interior of the narrow space at a preset speed and trajectory.

[0045] An automated spraying method for narrow, curved surfaces includes the following steps:

[0046] Step 1: Using the central axis of the narrow curved space as a reference, a crankshaft track 200 is installed inside the narrow curved space, and a spraying trolley 100 and a flexible traction device 300 are installed on the outside of the crankshaft track 200.

[0047] Step 2: Install the attitude adjuster at the calibration position outside the spraying carriage 100, and control the attitude adjuster to move to the zero position. Install the spray gun 400 at the calibration position on the attitude adjuster.

[0048] Step 3: Plan the motion trajectory of the spray gun 400 according to the shape of the inner surface of the narrow curved surface. The spraying carriage 100 is pulled along the crankshaft track 200 by the flexible traction device 300. During the traction process, the spray gun 400 is driven to rotate circumferentially and move radially by the attitude adjuster, so that the spray gun 400 moves along the planned motion trajectory to spray the narrow curved surface.

[0049] Furthermore, step 1 includes:

[0050] Step 1.1, Offline trajectory programming design: Based on the theoretical narrow curved surface model, the motion trajectory of the spraying cart 100 under theoretical conditions is obtained through simulation; the motion trajectory of the spraying cart 100 is extracted to design the theoretical central crankshaft, and the crankshaft track 200 is designed with the theoretical central axis of the theoretical narrow curved surface model;

[0051] Step 1.2: Based on the theoretical narrow curved surface model, establish a spatial coordinate system, select external measurable positions on the theoretical narrow curved surface model, and arrange multiple first-type feature points Q along the axial and circumferential directions. i Extract the first theoretical coordinates of the first type of feature points. Each first type of feature point has a unique first theoretical coordinate (xq) in the spatial coordinate system. i A, yq i A, zq i A), the set is denoted as {Q} i A}={Q1A,Q2A, ...,Q n A}; Multiple second-type feature points P are arranged along the axial and circumferential directions at external measurable locations on the crankshaft track 200. i Extract the second theoretical coordinates of the second type of feature points. The second theoretical coordinates of each second type of feature point in the spatial coordinate system are (xp iA, yp i A, zp i A), the set is denoted as {P} i A}={P1A,P2A, ...,P n A};

[0052] Step 1.3: Based on the theoretical central axis, several segmented arc-shaped track modules 201 are pre-assembled into a crankshaft track 200 by embedding them into a narrow curved surface space. The crankshaft track 200 is formed by embedding and splicing segmented arc-shaped track modules 201. Adjacent segmented arc-shaped track modules 201 are connected by positioning pins 202 and fastening bolts 203. The positioning pins 202 are evenly distributed circumferentially at the docking part of the track modules. Adjustable support units 204 are set at both ends of the crankshaft track 200. The adjustable support units 204 are fixedly connected to the crankshaft track 200. A set of adjustable support units 204 includes adjustable screws 2... 041, screw sleeve 2042, locking nut 2043, and support leg 2044. The screw sleeve 2042 and the support leg 2044 are connected by a universal ball joint. The screw sleeve 2042 has holes arranged in the circumferential direction. The support leg 2044 is in contact with the curved space wall with a soft and non-slip material. The length of the adjustable support unit 204 can be adjusted by inserting the adjusting tool rod 205 into the holes arranged in the circumferential direction of the screw sleeve 2042 and rotating the screw sleeve 2042. At least 3 sets of adjustable support units are arranged in the circumferential direction at each end of the crankshaft track 200. The initial adjustment of the crankshaft track 200 is achieved by adjusting multiple sets of adjustable support units 204.

[0053] Step 1.4: Establish a world coordinate system. Measure the first actual coordinates of the first type of feature points in the world coordinate system, denoted as QiS. Measure the second actual coordinates of the second type of feature points, denoted as PiS. Calculate the position transformation matrix between the spatial coordinate system and the world coordinate system based on the difference between the first theoretical coordinates and the first actual coordinates. The position transformation matrix includes a rotation matrix and a translation matrix. The position transformation matrix makes: QiA = RAS{QiS} + TAS, where RAS represents the rotation matrix and TAS represents the translation matrix.

[0054] Step 1.5: Based on the position transformation matrix, transform the second type of feature points on crankshaft track 200 from the world coordinate system to the spatial coordinate system to obtain the second transformed coordinates of the second feature points, denoted as Pi'A;

[0055] Step 1.6: Calculate the deviation representation between the second theoretical coordinate and the second transformed coordinate. Adjust the pose of each segmented arc track module based on the deviation vector until the deviation representation between the second theoretical coordinate and the second transformed coordinate meets the standard. The deviation representation includes the deviation vector ΔPi = Pi'A - PiA between the second theoretical coordinate and the second transformed coordinate. When ||ΔPi|| ≤ ±5mm, it is determined that the deviation representation meets the standard. Tighten the locking nut 2043 to lock the adjustment tool rod 205. After multiple sets of adjustment tool rods 205 are locked, the pose of the crankshaft track 200 is locked.

[0056] Step 1.7: Fix each segmented arc track module, and install the spraying trolley 100 and flexible traction device 300 on the outside of the formed crankshaft track 200.

[0057] Example 2:

[0058] This embodiment discloses an automatic spraying device for narrow, curved surfaces, which is an improvement on Embodiment 1, such as... Figure 1 and Figure 2 As shown, the attitude adjuster includes a circumferential rotation mechanism 104 and a radial linear movement mechanism 105. The circumferential rotation mechanism 104 is coaxially rotatably sleeved on the outside of the spraying carriage 100. The radial linear movement mechanism 105 is provided on the rotating end of the circumferential rotation mechanism 104, and a spray gun 400 is provided on the moving end of the radial linear movement mechanism 105. A counterweight adjustment part 106 is provided on the rotating frame 1043 on the opposite side of the radial linear movement mechanism 105.

[0059] The circumferential rotation mechanism 104 is used to drive the spray gun 400 to rotate circumferentially, and the radial linear movement mechanism 105 is used to drive the spray gun 400 to move radially linearly. In turn, in conjunction with the movement of the spraying carriage 100 along the crankshaft track 200, the movement trajectory of the spray gun 400 is coupled and controlled, so that the spray gun 400 sprays the interior of the narrow curved space according to the predetermined movement trajectory.

[0060] In order to control the center of gravity of the entire spraying device, a counterweight adjustment unit 106 is provided on the rotary frame 1043 on the opposite side of the radial linear movement mechanism 105. The counterweight adjustment unit 106 includes a counterweight water tank that can be filled and drained. By controlling the amount of water filled and drained from the counterweight water tank, the weight of the entire counterweight adjustment unit 106 is controlled so that the center of gravity of the entire spraying device is roughly controlled on the central axis of the crankshaft track 200, thereby ensuring the stability of the spraying operation.

[0061] Furthermore, such as Figure 4As shown, the circumferential rotation mechanism 104 includes a rotation fixed bracket 1041, a rotation bearing 1042, a rotation frame 1043, and a rotation drive mechanism 1044. The rotation fixed bracket 1041 is fixedly installed on the outside of the spray painting cart 100. The rotation bearing 1042 is coaxially arranged inside the rotation fixed bracket 1041, and the rotation drive mechanism 1044 is arranged on the rotation fixed bracket 1041. The rotation frame 1043 is rotatably installed inside the rotation bearing 1042, and a radial linear movement mechanism 105 is arranged on the rotation frame 1043. The rotation drive mechanism 1044 is used to drive the rotation frame 1043 to rotate circumferentially.

[0062] The rotary drive mechanism 1044 includes a rotary motor, a drive gear, and a driven gear ring. The driven gear ring is installed inside the rotary frame 1043, and the rotary motor is installed on the rotary fixed bracket 1041. The output shaft of the rotary motor is fitted with a drive gear that meshes with the driven gear ring. The rotary motor drives the drive gear to rotate, which in turn drives the driven gear ring and the rotary frame 1043 to rotate circumferentially, ultimately driving the spray gun 400 to rotate circumferentially.

[0063] Furthermore, such as Figure 5 As shown, the radial linear movement mechanism 105 includes a radial fixed bracket 1051, a slide rail 1052, a slider 1053, and a linear drive mechanism 1054. The radial fixed bracket 1051 is fixedly mounted on the rotary frame 1043. The slide rail 1052 and the linear drive mechanism 1054 are provided on the radial fixed bracket 1051. The slider 1053 is slidably mounted on the slide rail 1052. A spray gun 400 is mounted on the slider 1053. The drive end of the linear drive mechanism 1054 is connected to one side of the slider 1053.

[0064] The linear drive mechanism 1054 includes a linear motor and a screw. One side of the slider 1053 is threadedly connected to the screw via a threaded hole. The screw is rotatably mounted on the radial fixed bracket 1051. The output shaft of the linear motor is connected to one end of the screw. The linear motor drives the screw to rotate, which in turn drives the slider 1053 to move linearly along the slide rail 1052, thereby driving the spray gun 400 to move radially linearly.

[0065] The rest of this embodiment is the same as that of Embodiment 1, so it will not be described again.

[0066] Example 3:

[0067] This embodiment discloses an automatic spraying device for narrow, curved surfaces, which is an optimization based on Embodiment 1 or 2, such as... Figure 2 and Figure 3As shown, the swing guide includes a guide frame, support rollers 102, and ball joints 103. The guide frame is sleeved on the outside of the crankshaft track 200. The opposite sides of the guide frame are connected to the ends of the spraying carriage 100 through the ball joints 103. A plurality of support rollers 102 are rotatably arranged on the inner wall of the guide frame. The support rollers 102 are in rolling contact with the outer surface of the crankshaft track 200.

[0068] The painting carriage 100 includes a frame body 101, with connecting brackets at both the front and rear ends of the frame body 101. The two opposite side walls of the guide frame are rotatably connected to the connecting brackets via ball joints 103. The guide frame is rectangular, and four sets of support rollers 102 are rotatably mounted on the inner wall of the guide frame. The outer surfaces of the support rollers 102 roll in contact with the outer surface of the crankshaft track 200, allowing the guide frame to swing freely via the ball joints 103 during the movement of the painting carriage 100. This ensures that the outer surfaces of the support rollers 102 are always in contact with the outer surface of the crankshaft track 200, guaranteeing that the painting carriage 100 moves smoothly along the crankshaft track 200. Through the intermittent movement of the painting carriage 100, the central axis of the entire narrow curved surface space is divided from the curve into several sequentially connected line segments. By adjusting the circumferential rotation angle and radial movement position of the spray gun 400 on each line segment, the painting of the narrow curved surface space is achieved.

[0069] The rest of this embodiment is the same as that of embodiment 1 or 2, so it will not be described again.

[0070] Example 4:

[0071] This embodiment discloses an automatic spraying device for narrow, curved surfaces, which is an optimization based on any one of embodiments 1-3, such as... Figure 6 As shown, the flexible traction device 300 includes a flexible traction rope 301, a traction wheel 302, and a traction wheel drive mechanism 303. A traction groove is provided on the side wall of the crankshaft track 200. Traction wheels 302 are rotatably mounted at both ends of the traction groove, and the flexible traction rope 301 is wound between the two traction wheels 302. The flexible traction rope 301 is connected to the painting carriage 100, and the traction wheel 302 is drively connected to the traction wheel drive mechanism 303. The flexible traction rope 301 is confined inside the traction groove by a pressure roller. The traction wheel drive mechanism 303 drives the traction wheel 302 to rotate, thereby winding the flexible traction rope 301. The flexible traction rope 301 drives the painting carriage 100 to move along the crankshaft track 200.

[0072] The traction wheel drive mechanism 303 can be either a belt drive mechanism or a gear drive mechanism.

[0073] The rest of this embodiment is the same as any one of embodiments 1-3, so it will not be described again.

[0074] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. An automatic spraying method for a narrow curved surface space, implemented based on an automatic spraying device, the automatic spraying device including a crankshaft track (200) adapted to the central axis of the narrow curved surface space, a spraying carriage (100) sleeved on the outside of the crankshaft track (200), and swing guides at both ends of the spraying carriage (100) that slide and conform to the surface of the crankshaft track (200); an attitude adjuster is provided on the outside of the spraying carriage (100) that can rotate circumferentially and move radially relative to the inner surface contour of the narrow curved surface space, a spray gun (400) is provided on the actuating end of the attitude adjuster, and a flexible traction device (30) is provided on the outside of the crankshaft track (200). 0), the traction end of the flexible traction device (300) is connected to the spray painting carriage (100), and the traction end of the flexible traction device (300) always conforms to the crankshaft track (200) during the traction process; the attitude adjuster includes a circumferential rotation mechanism (104) and a radial linear movement mechanism (105). The circumferential rotation mechanism (104) is coaxially rotated and sleeved on the outside of the spray painting carriage (100). The radial linear movement mechanism (105) is provided on the rotation end of the circumferential rotation mechanism (104), and a spray gun (400) is provided on the moving end of the radial linear movement mechanism (105); the circumferential rotation mechanism (104) includes a rotation fixed bracket (1041) and a rotation bearing. (1042), a rotating frame (1043), and a rotating drive mechanism (1044). The rotating fixed bracket (1041) is fixedly installed on the outside of the spray painting cart (100). A rotating bearing (1042) is coaxially arranged inside the rotating fixed bracket (1041). A rotating drive mechanism (1044) is arranged on the rotating fixed bracket (1041). The rotating frame (1043) is rotatably installed inside the rotating bearing (1042). A radial linear movement mechanism (105) is arranged on the rotating frame (1043). The rotating drive mechanism (1044) is used to drive the rotating frame (1043) to rotate circumferentially. The radial linear movement mechanism (105) includes a radial fixed... The system comprises a fixed support (1051), a slide rail (1052), a slider (1053), and a linear drive mechanism (1054). The radial fixed support (1051) is fixedly mounted on a rotary frame (1043). The radial fixed support (1051) is provided with a slide rail (1052) and a linear drive mechanism (1054). The slider (1053) is slidably mounted on the slide rail (1052). A spray gun (400) is mounted on the slider (1053). The drive end of the linear drive mechanism (1054) is connected to one side of the slider (1053). A counterweight adjustment part (106) is provided on the rotary frame (1043) on the opposite side of the radial linear movement mechanism (105).The swing guide includes a guide frame, support rollers (102), and ball joints (103). The guide frame is sleeved on the outside of the crankshaft track (200). The opposite sides of the guide frame are connected to the ends of the spraying carriage (100) through ball joints (103). Several support rollers (102) are rotatably arranged on the inner wall of the guide frame. The support rollers (102) are in rolling contact with the outer surface of the crankshaft track (200). The flexible traction device (300) includes a flexible traction rope (301), a traction wheel (302), and a traction wheel drive mechanism (303). A traction groove is provided on the side wall of the crankshaft track (200). Traction wheels (302) are rotatably installed at both ends of the traction groove. A flexible traction rope (301) is wound between the traction wheels (302) at both ends. The flexible traction rope (301) is connected to the spraying carriage (100). The traction wheel (302) is connected to the traction wheel drive mechanism (303) in a transmission connection. Its features are, Includes the following steps: Step 1: Using the central axis of the narrow curved space as a reference, a crankshaft track (200) is erected inside the narrow curved space, and a spraying trolley (100) and a flexible traction device (300) are installed on the outside of the crankshaft track (200). Step 2: Install the attitude adjuster at the calibration position outside the spraying carriage (100) and control the attitude adjuster to move to the zero position. Install the spray gun (400) at the calibration position on the attitude adjuster. Step 3: Plan the motion trajectory of the spray gun (400) according to the shape of the inner surface of the narrow curved surface space. Use the flexible traction device (300) to pull the spraying carriage (100) along the crankshaft track (200). During the traction process, the attitude adjuster drives the spray gun (400) to rotate circumferentially and move radially, so that the spray gun (400) moves along the planned motion trajectory to complete the spraying of the narrow curved surface. Step 1 includes: Step 1.1, Offline trajectory programming design: Based on the theoretical narrow curved surface model, the motion trajectory of the spraying cart (100) under theoretical conditions is obtained through simulation; the motion trajectory of the spraying cart (100) is extracted to design the theoretical center crankshaft, and the crankshaft track (200) is designed with the theoretical center axis of the theoretical narrow curved surface model. Step 1.2: Based on the theoretical narrow curved surface model, establish a spatial coordinate system, select an external measurable position on the theoretical narrow curved surface model, and arrange multiple first-type feature points along the axial and circumferential directions, and extract the first theoretical coordinates of the first-type feature points; select an external measurable position on the crankshaft track (200) and arrange multiple second-type feature points along the axial and circumferential directions, and extract the second theoretical coordinates of the second-type feature points; Step 1.3: Based on the theoretical central axis, several segmented arc track modules (201) are embedded into the narrow curved space and pre-assembled to form the crankshaft track (200). Step 1.4: Establish a world coordinate system, measure the first actual coordinates of the first type of feature points and the second actual coordinates of the second type of feature points in the world coordinate system; calculate the position transformation matrix between the spatial coordinate system and the world coordinate system based on the difference between the first theoretical coordinates and the first actual coordinates. Step 1.5: Based on the position transformation matrix, transform the second type of feature points on the crankshaft track (200) from the world coordinate system to the spatial coordinate system to obtain the second transformed coordinates of the second feature points; Step 1.6: Calculate the deviation representation between the second theoretical coordinates and the second transformed coordinates, and adjust the pose of each segmented arc track module (201) based on the deviation vector until the deviation representation between the second theoretical coordinates and the second transformed coordinates meets the standard. Step 1.7: Fix each segmented arc track module (201) and install the spraying trolley (100) and flexible traction device (300) on the outside of the formed crankshaft track (200).

2. The automatic spraying method for narrow curved surfaces according to claim 1, characterized in that, The deviation characterization quantity includes the deviation vector ΔP between the second theoretical coordinates and the second transformed coordinates. i When ||△P i ||≤±5mm is used to determine whether the deviation meets the standard.

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