Positioning device for detection robot in pipeline

Abstract

The utility model provides a positioning device for a detection robot in a pipeline. The positioning device comprises an underwater camera, an underwater encoder, an underwater encoder mounting arm, a flow meter and a pulse processing circuit, the underwater camera is mounted on the robot body and is in signal connection with a controller of the robot body, the underwater encoder is fixedly mounted on the robot body through an underwater encoder mounting arm, and the flow meter is mounted on the robot body; a contact roller of the underwater encoder mounting arm is in contact with the inner wall of the pipeline, and the contact roller is in transmission connection with the underwater encoder; the detection robot positioning system has multiple working modes, can realize detection robot positioning under multiple working conditions, and can realize robot positioning in pipelines in full water and semi-water states through cooperation of the underwater camera and the underwater encoder or the flow meter. The robot working in the pipeline in the emptying state can be positioned by matching the underwater camera with the underwater encoder, and all working states of the pipeline can be covered by the three matching modes.

Description

Technical Field

[0001] The utility model relates to the technical field of robot positioning, in particular to a positioning device for an in-pipeline detection robot. Background Art

[0002] Underground pipe networks are a crucial component of municipal infrastructure. Cities are crisscrossed with various pipelines, including stormwater pipes, water supply pipes, and sewage pipes. Smaller diameters, such as those of DN300 and DN400, are difficult for operators to access, hindering maintenance, inspection, and repair operations. Consequently, the development of robots capable of moving within pipelines has become an essential engineering technology. However, these robots often struggle with precise positioning, limiting the application and widespread adoption of pipe network technologies. Utility Model Content

[0003] In view of the defects in the prior art, the purpose of the present invention is to provide a positioning device for an in-pipeline inspection robot.

[0004] The in-pipeline inspection robot positioning device provided by the utility model includes an underwater camera, an underwater encoder, an underwater encoder mounting arm, a flow meter, and a pulse processing circuit;

[0005] The underwater camera is mounted on the robot body and is signal-connected to the controller of the robot body. The underwater encoder is fixedly mounted on the robot body via an underwater encoder mounting arm. The tachometer is mounted on the robot body.

[0006] The contact roller of the underwater encoder mounting arm contacts the inner wall of the pipe, and the contact roller is in transmission connection with the underwater encoder;

[0007] The underwater encoder and the current meter are both connected to the pulse processing circuit signal, and the pulse processing circuit is connected to the controller signal. The pulse processing circuit is used to receive the digital pulse signals emitted by the underwater encoder and the current meter, and send the shaped digital pulse signals to the controller.

[0008] Preferably, the underwater encoder mounting arm includes a contact roller, a synchronous pulley, a support plate, an elastic member and a fixing bracket;

[0009] The fixing bracket includes a contact roller fixing bracket and an elastic member fixing bracket, both of which are fixedly mounted on the robot body, the support plate is mounted on the contact roller fixing bracket, the contact roller is mounted on the end of the support plate, and the underwater encoder is mounted in the middle of the support plate;

[0010] The synchronous pulley includes a first pulley and a second pulley in transmission connection, the first pulley is coaxially fixedly connected to the contact roller, and the second pulley is coaxially connected to the underwater encoder;

[0011] One end of the elastic member is mounted on the elastic member fixing bracket, and the other end of the elastic member is connected to the support plate and is used to apply pressure to the contact roller toward the inner wall of the pipeline.

[0012] Preferably, the support plates are two, and the two support plates are arranged side by side on the contact roller fixing bracket, and a mounting position is formed between the two support plates;

[0013] The two ends of the roller shaft of the contact roller are respectively mounted on the inner side surfaces of the two support plates, and the first pulley is located on the outer side of the support plates and is coaxial with and fixedly connected to the roller shaft;

[0014] Among the two support plates, a supporting short shaft bracket is provided in the middle of the inner side surface of one of the support plates, the photoelectric encoder is installed in the supporting short shaft bracket, the photoelectric encoder is connected to the lower support shaft of the synchronous pulley through a coupling, and the lower support shaft of the synchronous pulley is installed on the inner side surface of the other support plate through the lower support shaft bracket of the synchronous pulley;

[0015] The second pulley is located on the outside of the other support plate, and is coaxial with and fixedly connected to the lower support shaft of the synchronous pulley. The first pulley and the second pulley are connected through a transmission belt.

[0016] Preferably, an intermediate support shaft is installed in the middle of the support plate, and an elastic member lower support shaft is installed in the elastic member fixing bracket;

[0017] The two ends of the elastic member are rotatably connected to the middle support shaft and the lower support shaft of the elastic member respectively, and the bottom of the support plate is rotatably connected to the contact roller fixing bracket.

[0018] Preferably, the elastic member comprises an air spring.

[0019] Preferably, the pulse processing circuit includes an encoder pulse processing circuit and a tachometer pulse processing circuit having the same structure;

[0020] The input end of the encoder pulse processing circuit is connected to the A-phase output and the B-phase output of the underwater encoder respectively, and the output end of the encoder pulse processing circuit is connected to the controller circuit;

[0021] The input end of the velocity meter pulse processing circuit is connected to the output end of the velocity meter, and the output end of the velocity meter pulse processing circuit is connected to the controller circuit.

[0022] Preferably, the encoder pulse processing circuit includes a first pulse processing circuit, a second pulse processing circuit and a trigger chip U3;

[0023] The input end of the first pulse processing circuit is connected to the A-phase output of the underwater encoder, and the output end of the first pulse processing circuit is connected to the first pin of the trigger chip U3;

[0024] The input end of the second pulse processing circuit is connected to the B-phase output of the underwater encoder, and the output end of the second pulse processing circuit is connected to the second pin of the trigger chip U3;

[0025] The third pin of the trigger chip U3 is connected to VCC.

[0026] Preferably, the first pulse processing circuit includes a PNP transistor Q1, an NPN transistor Q2, a capacitor C1, a resistor R1, a resistor R2, a resistor R3, a resistor R4 and a comparator U1;

[0027] The resistor R1 is respectively connected to the A-phase output of the underwater encoder and the base of the transistor Q1, the emitter of the transistor Q1 is connected to VCC, the collector of the transistor Q1 is connected to the base of the transistor Q2 and then to ground via the resistor R2, the collector of the transistor Q2 is pulled up to VCC via the resistor R3, and then connected to the non-inverting input of the comparator U1, the emitter of the transistor Q2 is grounded, the inverting input of the comparator U1 is pulled down to the ground via the resistor R4, the first pin of the comparator U1 is connected to VCC and decoupled to the ground via the capacitor C1, the second pin of the comparator U1 is grounded, and the third pin of the comparator U1 outputs the A-phase pulse signal of the underwater encoder and is connected to the first pin of the trigger chip U3.

[0028] Preferably, the second pulse processing circuit comprises a PNP transistor Q2, an NPN transistor Q4, a capacitor C2, a resistor R5, a resistor R6, a resistor R7, a resistor R8 and a comparator U2;

[0029] The resistor R8 is connected to the B-phase output of the underwater encoder and the base of the transistor Q3, respectively. The emitter of the transistor Q3 is connected to VCC. The collector of the transistor Q3 is connected to the base of the transistor Q4 and then to ground via a resistor R7. The collector of the transistor Q4 is pulled up to VCC via a resistor R6 and then connected to the non-inverting input of the comparator U2. The emitter of the transistor Q4 is grounded, and the inverting input of the comparator U2 is pulled down to ground via a resistor R5. The first pin of the comparator U2 is connected to VCC and decoupled to ground using a capacitor C2. The second pin of the comparator U2 is grounded. The third pin of the comparator U2 outputs the B-phase pulse signal of the underwater encoder and is connected to the second pin of the trigger chip U3.

[0030] Preferably, the fourth pin of the trigger chip U3 is grounded, and the third pin of the trigger chip U3 is connected to VCC and decoupled to the ground via the capacitor C3.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] The utility model has a simple structure, is easy to operate, and has multiple working modes. It can realize the precise positioning of the detection robot under various working conditions. By combining the underwater camera with the underwater encoder or the flow meter, the detection robot working in the full water or semi-water state pipeline can be positioned. By combining the underwater camera with the underwater encoder, the detection robot working in the empty state pipeline can be positioned. The three cooperation modes can cover all working states of the pipeline. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Other features, objects and advantages of the present invention will become more apparent from the detailed description of the non-limiting embodiments with reference to the following drawings:

[0034] Figure 1 It is the overall structural diagram of the utility model;

[0035] Figure 2 This is a structural diagram of the main viewing angle of the underwater encoder mounting arm in the utility model;

[0036] Figure 3 This is a schematic diagram of the structure of the side view angle of the underwater encoder installation arm in the utility model;

[0037] Figure 4 This is a schematic diagram of the structure of the underwater encoder mounting arm in the present invention from a top-down perspective;

[0038] Figure 5 This is a schematic diagram of the pulse processing circuit in the present invention.

[0039] The figure shows:

[0040] Contact roller 1 Photoelectric encoder 8

[0041] Roller shaft 2 Synchronous pulley lower support shaft 9

[0042] Synchronous pulley 3 Coupling 10

[0043] Support plate 4 Elastic member 11

[0044] Intermediate support shaft 5 fixed bracket 12

[0045] Support short shaft bracket 6 elastic member lower support shaft 13

[0046] Synchronous pulley lower support shaft bracket 7 DETAILED DESCRIPTION

[0047] The present invention will be described in detail below with reference to specific embodiments. The following embodiments will help those skilled in the art further understand the present invention, but are not intended to limit the present invention in any way. It should be noted that a person skilled in the art may make various variations and improvements without departing from the scope of the present invention. Such variations and improvements are all within the scope of protection of the present invention.

[0048] The utility model discloses a positioning device for an in-pipeline inspection robot. By using an underwater camera in conjunction with an underwater encoder or a flow meter, the inspection robot can be positioned in a pipeline that is full of water or half-water. By using an underwater camera in conjunction with an underwater encoder, the inspection robot can be positioned in an empty pipeline. The three coordination methods can cover all working states of the pipeline.

[0049] According to the in-pipeline detection robot positioning device provided by the utility model, Figure 1 As shown, it includes an underwater camera, an underwater encoder 8, an underwater encoder mounting arm, a current meter and a pulse processing circuit;

[0050] The underwater camera is installed on the robot body and is connected to the controller signal of the robot body. The underwater encoder 8 is fixedly installed on the robot body through the underwater encoder mounting arm, and the flow meter is installed on the robot body; the contact roller 1 of the underwater encoder mounting arm is in contact with the inner wall of the pipe, and the contact roller 1 is transmission-connected to the underwater encoder 8; the underwater encoder 8 and the flow meter are both connected to the pulse processing circuit signal, and the pulse processing circuit is connected to the controller signal. The pulse processing circuit is used to receive the digital pulse signals emitted by the underwater encoder 8 and the flow meter, and send the shaped digital pulse signals to the controller.

[0051] like Figure 2-4 As shown, the underwater encoder mounting arm includes a contact roller 1, a synchronous pulley 3, a support plate 4, an elastic member 11, and a fixed bracket 12. The fixed bracket 12 includes a contact roller fixing bracket and an elastic member fixing bracket, both of which are fixedly mounted on the robot body. The support plate 4 is mounted on the contact roller fixing bracket, the contact roller 1 is mounted on the end of the support plate 4, and the underwater encoder 8 is mounted in the middle of the support plate 4. The synchronous pulley 3 includes a first pulley and a second pulley in a transmission connection. The first pulley is coaxially fixedly connected to the contact roller 1, and the second pulley is coaxially connected to the underwater encoder 8. One end of the elastic member is mounted on the elastic member fixing bracket, and the other end of the elastic member is connected to the support plate 4 and is used to apply pressure to the contact roller 1 toward the inner wall of the pipe. Preferably, the elastic member 11 includes an air spring.

[0052] The support plates 4 are two pieces, and the two support plates 4 are arranged side by side on the contact roller fixing bracket, and a mounting position is formed between the two support plates 4; the two ends of the roller shaft 2 of the contact roller 1 are respectively mounted on the inner side surfaces of the two support plates 4, and the first pulley is located on the outer side of the support plate 4, and is coaxial with and fixedly connected to the roller shaft 2; among the two support plates 4, a supporting short shaft bracket 6 is provided in the middle part of the inner side surface of one of the support plates 4, and the photoelectric encoder 8 is installed in the supporting short shaft bracket 6, and the photoelectric encoder 8 is connected to the lower support shaft 9 of the synchronous pulley through a coupling 10, and the lower support shaft 9 of the synchronous pulley is mounted on the inner side surface of the other support plate 4 through the lower support shaft bracket 7 of the synchronous pulley; the second pulley is located on the outer side of the other support plate 4, and is coaxial with and fixedly connected to the lower support shaft 9 of the synchronous pulley, and the first pulley and the second pulley are connected by a transmission belt. An intermediate support shaft 5 is installed in the middle of the support plate 4, and an elastic member lower support shaft 13 is installed in the elastic member fixing bracket; the two ends of the elastic member 11 are rotatably connected to the intermediate support shaft 5 and the elastic member lower support shaft 13 respectively, and the bottom of the support plate 4 is rotatably connected to the contact roller fixing bracket.

[0053] Example 1

[0054] This embodiment discloses a positioning device for an in-pipeline inspection robot, comprising an underwater camera, an underwater encoder pulse acquisition and processing circuit, and a tachometer pulse acquisition and processing circuit. The underwater camera collects surveillance video from within the pipeline during the robot's motion, and a controller processes this video using optical flow principles and methods to obtain displacement data s1 of the robot with the pipeline entrance as the zero position. The underwater encoder 8 is fixed to the robot body via a fixed arm and is in reliable contact with the inner wall of the pipeline. The controller simultaneously collects pulse data output by the underwater encoder 8 and the tachometer, respectively obtaining robot displacement data s2 and s3 with the pipeline entrance as the zero position. The Kalman fusion method is then used to obtain high-precision and high-reliability robot position data within the pipeline.

[0055] The underwater camera is an IP68 waterproof sealed camera with an automatic fill light device, which is used to capture the video of the interior of the pipeline collected during the robot's movement, and is used for pipeline internal inspection and optical flow detection.

[0056] The underwater encoder pulse acquisition and processing circuit comprises a sealed photoelectric encoder 8 with an IP68 waterproof rating and corresponding hardware processing circuitry. The encoder is connected to the robot body via a fixed arm and pressed against the inner wall of the pipe, ensuring reliable contact between the encoder and the pipe wall. The pulse acquisition and processing circuit shapes and polarity-converts the encoder pulse signal, which is then fed into the controller to calculate the robot's displacement. This circuit serves as a backup and complement to the tachometer pulse acquisition and processing circuit, and can be used in partially flooded, fully flooded, and empty pipe states.

[0057] The core of the flowmeter pulse acquisition and processing circuit is a Hall effect flowmeter and corresponding hardware processing circuit. This circuit shapes the pulse signal from the flowmeter and feeds it into the controller for calculating the robot's displacement. It serves as a backup and complement to the underwater encoder pulse acquisition and processing circuit and is only suitable for use in half-filled and full-filled pipeline conditions. When the pipeline is empty, the flowmeter produces no pulse output.

[0058] The information processing process in this embodiment is as follows: After the system is powered on, the robot moves, and the underwater camera captures video of the interior of the pipeline and transmits it to the controller. The robot's displacement is calculated based on optical flow changes and a corresponding algorithm. The underwater encoder pulse acquisition and processing circuit operates, outputting a shaped and polarity-inverted digital signal to the controller to calculate the robot's displacement. When the pipeline is full or half full, the tachometer pulse acquisition and processing circuit operates, outputting a shaped and polarity-inverted digital signal to the controller to calculate the robot's displacement. When the pipeline is full or half full, the control system uses Kalman fusion to obtain the robot's displacement data derived from the optical flow, the robot's displacement data derived from the underwater encoder pulse acquisition and processing circuit, and the robot's displacement data derived from the tachometer pulse acquisition and processing circuit to obtain the final robot position data. When the pipeline is empty, the control system uses Kalman fusion to obtain the final robot position data.

[0059] Example 2

[0060] This embodiment is a preferred embodiment of embodiment 1, wherein the underwater camera is a SW-SK5 Ballas underwater camera. Key specifications include: 12VDC operating voltage, 1.8mm lens, 1 / 2.8" CMOS optical sensor, 0.001 lux, 2592×1944P5MP resolution, 50 FPS, support for multiple protocols including IPv4, IPv6, HTTPS, TCP / IP, and RTSP, and a maximum pressure resistance of 500 kPa.

[0061] The underwater encoder uses a BBK-38S06-P2K-S2-F incremental rotary encoder. Key specifications include 5VDC operating voltage, 1000 PPR, ±0.05% linear accuracy, NPN output type, and IP68 waterproof rating.

[0062] The flow meter uses a YF-B5 Hall effect water flow sensor. Main parameters: 5-18VDC operating voltage, output pulse duty cycle 50% ± 10%, pulse output signal type NPN.

[0063] like Figure 2As shown, the mechanical structure of the underwater encoder mounting arm mainly includes a contact roller 1, a roller shaft 2, a synchronous pulley 3, a support plate 4, an intermediate support shaft 5, a supporting short shaft bracket 6, a synchronous pulley lower support shaft bracket 7, an underwater encoder 8, a synchronous pulley lower support shaft 9, a coupling 10, an air spring, a fixed bracket 12 and an air spring lower support shaft. The contact roller 1 and synchronous pulley 3 are connected to the roller shaft 2 via flat keys, and the roller shaft 2 is connected to the support plate 4 via bearings, forming a revolving pair. The air spring is connected to the intermediate support shaft 4 via the middle hole of the upper joint, and the intermediate support shaft 4 is connected to the support plate 4 via bearings. The underwater encoder 8 is connected to the support plate 4 via bearings and a support short shaft bracket 6, and then to the synchronous pulley lower support shaft 9 via a coupling 10. The synchronous pulley lower support shaft 9 is connected to the support plate 4 via bearings and a synchronous pulley lower support shaft bracket 7, and then to the synchronous pulley 3. The two synchronous pulleys are synchronously connected to form a synchronous transmission passive feedback device. The air spring is connected to the fixed bracket 12 via the air spring lower support shaft 13 and bearings. The fixed bracket 12 is fixed to the robot body with bolts. The contact roller 1, roller shaft 2, synchronous pulley 3, support plate 4, intermediate support shaft 5, support short shaft bracket 6, synchronous pulley lower support shaft bracket 7, underwater encoder 8, synchronous pulley lower support shaft 9, coupling 10, air spring 11, fixed bracket 12, air spring lower support shaft and synchronous belt constitute the encoder position and speed feedback system.

[0064] All components in this embodiment are domestically produced, resulting in a highly versatile system with high reliability, stable performance, low cost, and easy replacement and upgrade. It also boasts a wide range of applications, encompassing all pipeline operating conditions. Furthermore, the underwater encoder pulse acquisition and processing circuit and the tachometer pulse acquisition and processing circuit serve as backup and complementary components, enabling simultaneous or independent Kalman fusion of robot displacement data derived from underwater camera optical flow, resulting in more reliable and accurate robot position data.

[0065] Example 3

[0066] This embodiment is a preferred embodiment of embodiment 1, wherein the pulse processing circuit includes PNP transistors Q1 and Q3, NPN transistors Q2 and Q4, capacitors C1 to C3, resistors R1 to R8, comparators U1 and U2, and a trigger chip U3;

[0067] Resistor R1 is connected to the A-phase output of underwater encoder 8 and the base of transistor Q1. The emitter of transistor Q1 is connected to VCC. The collector of transistor Q1 is connected to the base of NPN transistor Q2 and then to ground via resistor R2. The collector of transistor Q2 is pulled up to VCC via resistor R3 and then connected to the non-inverting input of comparator U1. The emitter of transistor Q2 is grounded. The inverting input of comparator U1 is pulled down to ground via resistor R4. Pin 5 of comparator U1 is connected to VCC and decoupled to ground using capacitor C1. Pin 2 of comparator U1 is grounded. Pin 1 outputs the A-phase pulse signal of underwater encoder 8 and is connected to pin 2 of trigger chip U3. Resistor R8 is connected to the A-phase output of underwater encoder 8 and the base of transistor Q3. The emitter of transistor Q3 is connected to VCC. The collector of transistor Q3 is connected to the base of NPN transistor Q4 and then to ground via resistor R7. The collector of transistor Q4 is pulled up to VCC via resistor R6 and then connected to the non-inverting input of comparator U2. The emitter of transistor Q4 is grounded. The inverting input of comparator U2 is pulled down to ground via resistor R5. Pin 5 of comparator U2 is connected to VCC and decoupled to ground via capacitor C2. Pin 2 of comparator U2 is grounded, while pin 1 outputs the B-phase pulse signal of underwater encoder 8 and is connected to pin 3 of trigger chip U3. Pin 7 of trigger chip U3 is grounded, while pin 14 is connected to VCC and decoupled to ground via capacitor C3. This circuit simultaneously outputs underwater encoder pulse signals corresponding to speed and movement, as well as encoder steering and robot motion direction signals.

[0068] The comparators U1 and U2 described above use the GS8743 chip from Juxun Semiconductor Technology (Shanghai) Co., Ltd. Its main parameters include an operating voltage of 2.7 to 5.5 V, rail-to-rail input / output, CMOS / TLL signal compatible output, low power consumption of 1.3 mA, and a transmission delay of 6 ns.

[0069] The trigger chip U3 is an XD74LS74 chip manufactured by Xinluda Information Technology (Xiamen) Co., Ltd. The main parameters are: operating voltage 4.75-5.25V, pulse width 25ns, output voltage ≥2.7V, and operating current <8mA.

[0070] The flow meter pulse circuit only needs to use a pulse processing circuit connected to pin 2 or pin 3 of the trigger chip U3.

[0071] After the system of this embodiment is powered on, the robot moves, and the control system simultaneously collects the video signal of the underwater camera, the pulse signal of the underwater encoder and the tachometer, and uses the optical flow algorithm, the number of pulses and the trigger chip output chip to determine its moving distance and direction.

[0072] This embodiment has the following advantages:

[0073] 1) A variety of working scenarios, using IP68 waterproof grade underwater encoder, can work in full water, half water and empty pipe state;

[0074] 2) Multiple working modes: The underwater camera can be used with an underwater encoder or flow meter to operate in full or half-water conditions. The underwater camera can be used with an underwater encoder to operate in an empty state. These three working modes can cover all working conditions of the pipeline.

[0075] 3) The underwater encoder is not directly connected to the robot's wheels, so it will not output any signal if the robot slips or gets stuck. Furthermore, the video captured by the underwater camera remains unchanged, so the optical flow algorithm will not output any position data, thus ensuring the accuracy and reliability of the robot's position and velocity estimates.

[0076] 4) The synchronous belt and synchronous pulley are installed on the outside of the fixed arm to reduce the weight of the system and ensure reliable transmission; and if the water in the pipeline is dirty or there are debris, it is convenient to protect the synchronous belt and pulley with a protective cover or other sealing method to avoid entanglement of foreign matter;

[0077] 5) Using air springs to press the roller against the inner wall of the pipe can ensure greater pressing force and adaptability to larger pipe diameters;

[0078] 6) The pulse circuit uses PNP transistors and NPN transistors for secondary inversion processing, which greatly improves the reliability and stability of pulse acquisition and processing; at the same time, the trigger chip can directly output the encoder steering signal and the robot movement direction signal, reducing the processor's computing burden.

[0079] In the description of this application, it should be understood that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0080] The above describes specific embodiments of the present invention. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art may make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. The embodiments of this application and the features in the embodiments may be combined with each other in any manner unless there is a conflict.

Claims

1. A positioning device for an in-pipeline inspection robot, characterized in that: It includes an underwater camera, an underwater encoder (8), an underwater encoder mounting arm, a current meter, and a pulse processing circuit; The underwater camera is mounted on the robot body and is connected to the controller signal of the robot body. The underwater encoder (8) is fixedly mounted on the robot body via an underwater encoder mounting arm. The tachometer is mounted on the robot body. The contact roller (1) of the underwater encoder mounting arm contacts the inner wall of the pipeline, and the contact roller (1) is in transmission connection with the underwater encoder (8); The underwater encoder (8) and the tachometer are both connected to the pulse processing circuit signal, and the pulse processing circuit is connected to the controller signal. The pulse processing circuit is used to receive the digital pulse signals sent by the underwater encoder (8) and the tachometer, and send the shaped digital pulse signals to the controller.

2. The in-pipeline inspection robot positioning device according to claim 1, characterized in that: The underwater encoder mounting arm comprises a contact roller (1), a synchronous pulley (3), a support plate (4), an elastic member (11) and a fixing bracket (12); The fixing bracket (12) includes a contact roller fixing bracket and an elastic member fixing bracket, the contact roller fixing bracket and the elastic member fixing bracket are both fixedly mounted on the robot body, the support plate (4) is mounted on the contact roller fixing bracket, the contact roller (1) is mounted on the end of the support plate (4), and the underwater encoder (8) is mounted in the middle of the support plate (4); The synchronous pulley (3) comprises a first pulley and a second pulley in transmission connection, the first pulley is coaxially fixedly connected to the contact roller (1), and the second pulley is coaxially connected to the underwater encoder (8); One end of the elastic member is mounted on an elastic member fixing bracket, and the other end of the elastic member is connected to a support plate (4) and is used to apply pressure to the contact roller (1) toward the inner wall of the pipe.

3. The in-pipeline inspection robot positioning device according to claim 2, characterized in that: The support plates (4) are two, and the two support plates (4) are arranged side by side on the contact roller fixing bracket, and a mounting position is formed between the two support plates (4); The two ends of the roller shaft (2) of the contact roller (1) are respectively mounted on the inner side surfaces of two support plates (4); the first pulley is located on the outer side of the support plate (4) and is coaxial with and fixedly connected to the roller shaft (2); Among the two support plates (4), a supporting short shaft bracket (6) is provided in the middle of the inner side surface of one of the support plates (4), the photoelectric encoder (8) is installed in the supporting short shaft bracket (6), the photoelectric encoder (8) is connected to the synchronous pulley lower support shaft (9) through a coupling (10), and the synchronous pulley lower support shaft (9) is installed on the inner side surface of the other support plate (4) through the synchronous pulley lower support shaft bracket (7); The second pulley is located outside the other support plate (4), and is coaxial with and fixedly connected to the synchronous pulley lower support shaft (9). The first pulley and the second pulley are connected via a transmission belt.

4. The in-pipeline inspection robot positioning device according to claim 2, characterized in that: An intermediate support shaft (5) is installed in the middle of the support plate (4), and an elastic member lower support shaft (13) is installed in the elastic member fixing bracket; The two ends of the elastic member (11) are rotatably connected to the middle support shaft (5) and the elastic member lower support shaft (13), respectively, and the bottom of the support plate (4) is rotatably connected to the contact roller fixing bracket.

5. The in-pipeline inspection robot positioning device according to claim 2, characterized in that: The elastic member (11) comprises an air spring.

6. The in-pipeline inspection robot positioning device according to claim 1, characterized in that: The pulse processing circuit includes an encoder pulse processing circuit and a tachometer pulse processing circuit with the same structure; The input end of the encoder pulse processing circuit is connected to the A-phase output and the B-phase output of the underwater encoder (8) respectively, and the output end of the encoder pulse processing circuit is connected to the controller circuit; The input end of the velocity meter pulse processing circuit is connected to the output end of the velocity meter, and the output end of the velocity meter pulse processing circuit is connected to the controller circuit.

7. The in-pipeline inspection robot positioning device according to claim 6, characterized in that: The encoder pulse processing circuit includes a first pulse processing circuit, a second pulse processing circuit and a trigger chip U3; The input end of the first pulse processing circuit is connected to the A-phase output of the underwater encoder (8), and the output end of the first pulse processing circuit is connected to the first pin of the trigger chip U3; The input end of the second pulse processing circuit is connected to the B-phase output of the underwater encoder (8), and the output end of the second pulse processing circuit is connected to the second pin of the trigger chip U3; The third pin of the trigger chip U3 is connected to VCC.

8. The in-pipeline inspection robot positioning device according to claim 7, characterized in that: The first pulse processing circuit includes a PNP transistor Q1, an NPN transistor Q2, a capacitor C1, a resistor R1, a resistor R2, a resistor R3, a resistor R4 and a comparator U1; The resistor R1 is connected to the A-phase output of the underwater encoder (8) and the base of the transistor Q1 respectively, the emitter of the transistor Q1 is connected to VCC, the collector of the transistor Q1 is connected to the base of the transistor Q2 and then grounded through the resistor R2, the collector of the transistor Q2 is pulled up to VCC through the resistor R3, and then connected to the non-inverting input end of the comparator U1, the emitter of the transistor Q2 is grounded, the inverting input end of the comparator U1 is pulled down to the ground through the resistor R4, the first pin of the comparator U1 is connected to VCC and decoupled to the ground through the capacitor C1, the second pin of the comparator U1 is grounded, and the third pin of the comparator U1 outputs the A-phase pulse signal of the underwater encoder (8) and is connected to the first pin of the trigger chip U3.

9. The in-pipeline inspection robot positioning device according to claim 7, characterized in that: The second pulse processing circuit comprises a PNP transistor Q2, an NPN transistor Q4, a capacitor C2, a resistor R5, a resistor R6, a resistor R7, a resistor R8 and a comparator U2; The resistor R8 is connected to the B-phase output of the underwater encoder (8) and the base of the transistor Q3 respectively. The emitter of the transistor Q3 is connected to VCC. The collector of the transistor Q3 is connected to the base of the transistor Q4 and then grounded via the resistor R7. The collector of the transistor Q4 is pulled up to VCC via the resistor R6 and then connected to the non-inverting input of the comparator U2. The emitter of the transistor Q4 is grounded. The inverting input of the comparator U2 is pulled down to ground via the resistor R5. The first pin of the comparator U2 is connected to VCC and decoupled to ground using the capacitor C2. The second pin of the comparator U2 is grounded. The third pin of the comparator U2 outputs the B-phase pulse signal of the underwater encoder (8) and is connected to the second pin of the trigger chip U3.

10. The in-pipeline inspection robot positioning device according to claim 7, characterized in that: The fourth pin of the trigger chip U3 is grounded, and the third pin of the trigger chip U3 is connected to VCC and decoupled to the ground via the capacitor C3.

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