An underwater robot navigation device and method with a trackball

Abstract

The present invention discloses an underwater robot navigation device with a trackball, which relates to the technical field of robot positioning and navigation, and includes a trackball, a lens module, an optical sensor module, a laser emission module, a digital signal processing module, and a power management module; the present invention also discloses an underwater robot, and the underwater robot navigation device with a trackball is installed at the bottom of the underwater robot and communicatively connected, and receives and responds to the displacement and speed information of the underwater robot navigation device; the present invention also discloses an underwater robot navigation method, including: S100, installation of the underwater robot navigation device, S200, startup of the underwater robot, S300, acquisition of an image array, S400, calculation of displacement and speed, S500, sending of navigation information, S600, response to navigation information. The present invention has greater fault tolerance for the material and flatness of the contact plane at the bottom of the pool, and the trackball can play a role in isolating the optical path from the pool environment, with less waterproofing difficulty and higher reliability of the navigation device.

Description

Technical Field

[0001] The present invention relates to the technical field of robot positioning and navigation, and particularly to an underwater robot navigation device and method with a trackball. Background Art

[0002] After a swimming pool has been used for some time, a layer of dirt will settle on the bottom and around the pool, which is difficult to clean thoroughly. Compared with manual cleaning, choosing to use an automatic swimming pool cleaning robot can achieve the goals of zero dead angle, convenience, and low cost. In order to improve the cleaning efficiency and intelligence level of the swimming pool robot, it is necessary to obtain the motion navigation and positioning information of the robot during the traveling process.

[0003] Currently, there are the following three technical solutions for underwater positioning:

[0004] 1. Positioning method based on inertial navigation. This solution calculates the relative displacement of the machine through inertial sensors (including acceleration sensors and gyro sensors) carried by the underwater robot. This solution often relies on complex algorithms, cannot guarantee its navigation accuracy, and has cumulative errors, unable to meet the requirements of long-term underwater work.

[0005] 2. Positioning method based on sonar. In water, electromagnetic signals attenuate relatively quickly, and it is impossible to measure distances through ultrasonic waves and infrared rays as in air. However, the navigation and positioning information can be obtained through a sonar transmitting device and a receiving device. Underwater acoustic positioning is usually used in fields such as waterway safety, mineral resource investigation, and submarine cable laying. This solution has a high cost and is not suitable for navigation in small-area water environments such as swimming pools.

[0006] 3. Underwater positioning method based on GPS. It is necessary to combine multiple GPS buoys. The underwater navigation transceiver sends positioning signals to the GPS buoys, and the GPS buoys modulate information such as underwater acoustic positioning signals, buoy attitude calibration data, and GPS signals and then send them to the data control center. The data control center fuses and processes the GPS reference station differential signals with the above information and calculates to obtain the underwater target position. This solution has a high cost and low accuracy, and multiple GPS buoys need to be installed and set up in advance, which is not suitable for the navigation tasks in the swimming pool environment.

[0007] Generally speaking, the main disadvantages of the existing technical solutions are the following three points:

[0008] 1. The beacon method needs to be arranged in advance and does not have convenience;

[0009] 2. The method of the underwater acoustic solution has a high cost and is not convenient to use in a small area such as a swimming pool;

[0010] 3. The accuracy of inertial navigation is low, and there are large cumulative errors, which is unreliable in engineering.

[0011] The optoelectronic navigation device has relatively strict requirements for the contact plane at the bottom of the pool. It needs to be as flat and smooth as possible. If there is dirt at the bottom of the pool, it will affect the accuracy of the optoelectronic navigation device. In addition, the light-transmitting hole of the optoelectronic navigation device is directly in contact with the internal environment of the pool, which has relatively high requirements for waterproofing and increases the overall cost.

[0012] Therefore, those skilled in the art are committed to developing an underwater robot navigation device and method with a trackball. Summary of the Invention

[0013] In view of the above-mentioned defects of the prior art, the technical problem to be solved by the present invention is how to reduce the cost of underwater navigation and positioning and improve the accuracy of underwater trajectory positioning.

[0014] The inventor uses a trackball. When the underwater robot navigation device has a relative displacement with the ground, the trackball rolls accordingly. By taking consecutive microscopic pictures of the trackball surface and comparing the differences between adjacent pictures, the displacement and speed information of the robot relative to the plane can be calculated. Without relying on an underwater communication device, the displacement and speed information of itself can be obtained. Install the navigation device with a trackball at the bottom of the underwater robot. As long as the movement of the navigation device with a trackball is completely transmitted to the trackball, the movement of the trackball can fully reflect the displacement and speed information of the navigation device, and the movement information of the underwater robot can be obtained. Compared with the optoelectronic navigation device, the navigation device with a trackball has more tolerance for the material and flatness of the contact plane at the bottom of the pool, and the trackball can play a role in isolating the light path from the pool environment, with less waterproofing difficulty and higher reliability of the navigation device.

[0015] In an embodiment of the present invention, an underwater robot navigation device with a trackball is provided, including a trackball, a lens module, an optical sensor module, a laser emission module, a digital signal processing module, and a power management module:

[0016] The trackball is arranged at the bottom of the underwater robot navigation device and is in direct contact with the pool surface. The surface of the trackball is covered with a material suitable for precise laser detection. The parallel laser beam is reflected by the upper surface of the trackball to generate a laser beam with trackball texture information.

[0017] The lens module is composed of a refraction sub-module and a convergence sub-module. The refraction sub-module is arranged above the upper surface of the trackball to enhance the brightness of the concentric laser beam emitted by the laser emission module and refract it into a parallel laser beam, which is incident on the upper surface of the trackball at a certain angle. The convergence sub-module is located above the upper surface of the trackball. The laser beam with trackball texture information reflected by the upper surface of the trackball passes through the convergence sub-module, converges into a concentric laser beam, and then is transmitted to the optical sensor module.

[0018] An optical sensor module is arranged above the converging sub-module, with uniformly arranged tiny photosensitive substances, receiving the concentric laser beams converged by the converging sub-module of the lens module, converting them into electrical signals proportional to the optical signals, and forming an image array.

[0019] A laser emission module is arranged above the refraction sub-module, emitting concentric laser beams towards the upper surface of the trackball.

[0020] A digital signal processing module includes a digital image chip, which is directly communicatively connected to the optical sensor module. In response to the image array sent by the optical sensor module, it performs cross-correlation operations to obtain the variation values in the X-axis and Y-axis directions of two consecutive image arrays in units of pixels, and through the conversion between pixels and actual physical distances, obtains displacement and velocity information.

[0021] A power management module is circuit-connected to the laser emission module, the optical sensor module, and the digital signal processing module to supply power.

[0022] Powered by the power management module, the laser emission module emits concentric laser beams, which are refracted by the refraction sub-module of the lens module into parallel laser beams and shoot towards the upper surface of the trackball at a certain angle. The parallel laser beams reflected by the upper surface of the trackball are converged into concentric laser beams by the converging sub-module of the lens module and transmitted to the optical sensor module to form an image array. The image array is transmitted to the digital signal processing module for cross-correlation operations, and finally displacement and velocity information are obtained.

[0023] Optionally, in the underwater robot navigation device with a trackball in the above embodiment, the materials suitable for precise laser detection include thermoplastic polyurethane.

[0024] Optionally, in the underwater robot navigation device with a trackball in any of the above embodiments, the certain angle is preferably between 15 - 45°.

[0025] Further, in the underwater robot navigation device with a trackball in the above embodiment, the trackball is arranged above the bottom plate of the underwater robot navigation device. The bottom plate is provided with holes to fix the trackball, and a fixing plate for applying pressure to the trackball is arranged above the bottom plate. The trackball is between the bottom surface of the pool and the fixing plate and is in contact with the bottom surface of the pool and the fixing plate. When the underwater robot navigation device moves, the trackball rolls, and the movement of the trackball reflects the movement of the underwater robot navigation device.

[0026] Further, in the underwater robot navigation device with a trackball in the above embodiment, a waterproof sealing ring is arranged at the contact part between the trackball fixing plate and the trackball to prevent water from being brought into the interior of the navigation device when the trackball rolls and ensure the safety of the internal circuit.

[0027] Further, in the underwater robot navigation device with a trackball in the above embodiment, the surface area of the trackball illuminated by the parallel laser beam is 5 square millimeters.

[0028] Optionally, in the underwater robot navigation device with a trackball in any of the above embodiments, a black bottom plate is provided between the lens module and the power management module, the laser emission module, the optical sensor module, and the digital signal processing module to prevent light interference.

[0029] Optionally, in the underwater robot navigation device with a trackball in any of the above embodiments, the optical sensor module is provided with a light-transmitting hole to receive the concentric laser beam converged by the converging sub-module of the lens module. A waterproof gasket is provided for the light-transmitting hole to protect the internal circuit structure.

[0030] Optionally, in the underwater robot navigation device with a trackball in any of the above embodiments, the size of the image array is 40x40 pixels, and each pixel consists of gray levels in the range of 0 - 4095. The gray levels are determined by the light intensity received at specific pixel positions in the optical sensor module.

[0031] Optionally, in the underwater robot navigation device with a trackball in any of the above embodiments, the refraction sub-module uses a prism.

[0032] Optionally, in the underwater robot navigation device with a trackball in any of the above embodiments, the refraction sub-module uses a convex lens spherical surface, and the number of reflection planes is one to three, which is selected according to different light guiding schemes.

[0033] Optionally, in the underwater robot navigation device with a trackball in any of the above embodiments, the converging sub-module uses a circular lens.

[0034] The inventor connected the underwater robot navigation device with a trackball in the above embodiment to the underwater robot control board to provide the displacement and speed information required for navigation to the robot.

[0035] Based on any of the above embodiments, in another embodiment of the present invention, an underwater robot is provided. The underwater robot navigation device with a trackball in any of the above embodiments is installed at the bottom of the underwater robot and communicatively connected to receive and respond to the displacement and speed information of the underwater robot navigation device with a trackball.

[0036] Based on any of the above embodiments, in another embodiment of the present invention, an underwater robot navigation method is provided, including the following steps:

[0037] S100. Installation of the underwater robot navigation device. The underwater robot navigation device is installed at the bottom of the underwater robot;

[0038] S200. The underwater robot is activated and placed in the pool, and the underwater robot and its navigation device start to work.

[0039] S300. Image array acquisition: The laser emission module emits concentric laser beams onto the upper surface of the trackball. After being reflected and converged by the lens module, an image array is formed on the optical sensor module.

[0040] S400. Displacement and velocity calculation: The digital signal processing module receives the image array and performs cross-correlation operations. Continuously move the coordinate position of the latter frame of the image array while keeping the former frame of the image array fixed. Compare the differences between the two image arrays. When the difference is the smallest, determine the variation values in the X-axis and Y-axis directions in terms of pixels for two adjacent image arrays. Through the conversion between pixels and actual physical distances, displacement and velocity information is obtained.

[0041] S500. Navigation information transmission: The digital signal processing module sends the displacement and velocity information to the underwater robot for navigation.

[0042] S600. Navigation information response: The underwater robot receives and responds to the displacement and velocity information.

[0043] Optionally, in the underwater robot navigation method in the above embodiment, step S100 includes:

[0044] S110. Install the underwater robot navigation device at the bottom of the underwater robot, with the bottom of the underwater robot navigation device close to the bottom of the pool, and the maximum interval not exceeding 1 mm.

[0045] S120. Connect the underwater robot navigation device and the underwater robot through a USB cable to transmit navigation data and provide power.

[0046] Optionally, in the underwater robot navigation method in any of the above embodiments, in step S300, the size of the image array is 40x40 pixels, and each pixel consists of gray levels in the range of 0 - 4095. The gray levels are determined by the light intensity received at specific pixel positions in the optical sensor module.

[0047] Optionally, in the underwater robot navigation method in any of the above embodiments, step S300 includes:

[0048] S310. Laser emission: The laser emission module emits concentric laser beams onto the upper surface of the trackball.

[0049] S320. Lens module refraction: The refraction sub-module of the lens module increases the brightness of the concentric laser beams emitted by the laser emission module and refracts them into parallel laser beams at a certain angle and shoots them onto the upper surface of the trackball.

[0050] S330. When the underwater robot moves, the bottom surface of the pool and the track ball fixing plate exert pressure on the track ball. The track ball generates frictional force with the bottom surface of the pool, driving the track ball to roll on the plane of the pool surface, reflecting the relative displacement and speed between the underwater robot and the pool surface.

[0051] S340. Reflection on the upper surface of the track ball. The parallel laser beam is reflected by the upper surface of the track ball, generating a laser beam with the texture information of the track ball.

[0052] S350. Convergence by the lens module. The laser beam with the texture information of the track ball is converged into a concentric laser beam by the converging sub-module of the lens module and transmitted to the optical sensor module.

[0053] S360. Formation of the image array. The optical sensor module receives the concentric laser beam converged by the converging sub-module, converts it into an electrical signal proportional to the optical signal, and forms an image array.

[0054] Further, in the underwater robot navigation method in the above embodiment, in step S320, the certain angle is preferably between 15 - 45°.

[0055] The present invention uses the movement of the track ball to reflect the displacement and speed information of the navigation device. Without relying on the underwater communication device, the underwater robot can obtain its own displacement and speed information, reducing the cost of underwater navigation and positioning and improving the positioning accuracy. Compared with the optoelectronic navigation device, the underwater robot navigation device with a track ball has more tolerance for the material and flatness of the contact plane at the bottom of the pool, and the track ball can isolate the optical path from the pool environment, making the waterproofing difficult less and the reliability of the navigation device higher.

[0056] Hereinafter, the concept, specific structure and technical effects of the present invention will be further described with reference to the accompanying drawings to fully understand the purpose, features and effects of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 is a schematic structural diagram of an underwater robot navigation device according to an exemplary embodiment;

[0058] Figure 2 is a flowchart of an underwater robot navigation method according to an exemplary embodiment. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0059] The following introduces multiple preferred embodiments of the present invention with reference to the accompanying drawings of the specification to make its technical content clearer and easier to understand. The present invention can be embodied in many different forms of embodiments, and the protection scope of the present invention is not limited to the embodiments mentioned in the text.

[0060] In the drawings, components with the same structure are denoted by the same numerical reference signs, and components with similar structures or functions are denoted by similar numerical reference signs. The dimensions and thicknesses of each component shown in the drawings are arbitrarily illustrated, and the present invention does not limit the dimensions and thicknesses of each component. To make the illustration clearer, the thicknesses of some components are schematically exaggerated appropriately in the drawings.

[0061] The inventor has designed an underwater robot navigation device, as Figure 1 shown, which includes a trackball, a lens module, an optical sensor module, a laser emission module, a digital signal processing module, and a power management module:

[0062] The trackball is disposed at the bottom of the underwater robot navigation device and is in direct contact with the surface of the pool. The surface of the trackball is covered with a material suitable for precise laser detection, including thermoplastic polyurethane. The parallel laser beam is reflected by the upper surface of the trackball to generate a laser beam with the texture information of the trackball.

[0063] The lens module consists of a refraction sub-module and a convergence sub-module. The refraction sub-module preferably uses a prism, and a convex lens spherical surface can also be used. The number of reflection planes is one to three, which is selected according to different light guiding schemes. The convergence sub-module uses a circular lens. The refraction sub-module is disposed above the upper surface of the trackball to enhance the brightness of the concentric laser beam emitted by the laser emission module and refract it into a parallel laser beam, which is incident on the upper surface of the trackball at an angle, preferably between 15 - 45°. The surface area of the trackball illuminated by the parallel laser beam is approximately 5 square millimeters. The convergence sub-module is located above the upper surface of the trackball. The laser beam with the texture information of the trackball reflected by the upper surface of the trackball passes through the convergence sub-module, converges into a concentric laser beam, and then is transmitted to the optical sensor module.

[0064] The optical sensor module is disposed above the convergence sub-module and is provided with uniformly arranged minute photosensitive substances. It receives the concentric laser beam converged by the convergence sub-module of the lens module, converts it into an electrical signal proportional to the optical signal, and forms an image array. The size of the image array is 40x40 pixels, and each pixel consists of a gray level in the range of 0 - 4095. The gray level is determined by the light intensity received at a specific pixel position in the optical sensor module. The optical sensor module is provided with a light transmission hole, and the concentric laser beam converged by the convergence sub-module of the lens module is received through the light transmission hole. The light transmission hole is provided with a waterproof gasket to protect the internal circuit structure.

[0065] The laser emission module is disposed above the refraction sub-module and emits a concentric laser beam to the upper surface of the trackball.

[0066] The digital signal processing module includes a digital image chip, which is directly communicatively connected to the optical sensor module. In response to the image array sent by the optical sensor module, it performs cross-correlation operations to obtain the variation values of two consecutive image arrays in the X-axis and Y-axis directions in terms of pixels. Through the conversion between pixels and actual physical distances, displacement and velocity information is obtained.

[0067] The trackball is arranged above the bottom plate of the underwater robot navigation device. The bottom plate is provided with holes to fix the trackball. Above the bottom plate, there is a fixing plate that applies pressure to the trackball. The trackball is located between the bottom surface of the pool and the fixing plate and is in contact with both the bottom surface of the pool and the fixing plate. When the underwater robot navigation device moves, the trackball rolls, and the movement of the trackball reflects the movement of the underwater robot navigation device. A waterproof sealing ring is provided at the contact part between the trackball fixing plate and the trackball to prevent water from being brought into the interior of the navigation device when the trackball rolls, ensuring the safety of the internal circuit.

[0068] A black bottom plate is provided between the lens module and the power management module, the laser emission module, the optical sensor module, and the digital signal processing module to prevent light interference.

[0069] The power management module is circuit-connected to and supplies power to the laser emission module, the optical sensor module, and the digital signal processing module.

[0070] Powered by the power management module, the laser emission module emits concentric laser beams. The refraction sub-module of the lens module refracts them into parallel laser beams, which are emitted at a certain angle towards the upper surface of the trackball. The parallel laser beams reflected by the upper surface of the trackball are converged into concentric laser beams by the converging sub-module of the lens module and transmitted to the optical sensor module to form an image array. The image array is transmitted to the digital signal processing module for cross-correlation operations, and finally displacement and velocity information is obtained.

[0071] The inventor connected the underwater robot navigation device of the above embodiment to the underwater robot control board to provide the displacement and velocity information required for navigation to the robot.

[0072] Based on the above embodiment, in another embodiment of the present invention, an underwater robot is provided. The underwater robot navigation device with a trackball is installed at the bottom of the underwater robot and is communicatively connected to receive and respond to the displacement and velocity information of the underwater robot navigation device.

[0073] Based on the above embodiment, the inventor provides an underwater robot navigation method, as Figure 2 shown, including the following steps:

[0074] S100. Installation of the underwater robot navigation device. The underwater robot navigation device is installed at the bottom of the underwater robot, including:

[0075] S110. Install the underwater robot navigation device at the bottom of the underwater robot. The bottom of the underwater robot navigation device is close to the bottom of the pool, with a maximum gap of no more than 1 mm.

[0076] S120. Connect the underwater robot navigation device and the underwater robot through a USB cable to transmit navigation data and provide power.

[0077] S200. Start the underwater robot and place it in the pool. The underwater robot and the underwater robot navigation device start to work.

[0078] S300. Image array acquisition. The laser emission module emits concentric laser beams onto the upper surface of the trackball. After being reflected and converged by the lens module, an image array is formed on the optical sensor module. The size of the image array is 40x40 pixels, and each pixel consists of gray levels in the range of 0 - 4095. The gray levels are determined by the light intensity received at specific pixel positions in the optical sensor module. It includes:

[0079] S310. Laser emission. The laser emission module emits concentric laser beams onto the upper surface of the trackball.

[0080] S320. Refraction by the lens module. The refraction sub-module of the lens module increases the brightness of the concentric laser beams emitted by the laser emission module and refracts them into parallel laser beams, which are incident on the upper surface of the trackball at an angle, preferably between 15 - 45°.

[0081] S330. When the underwater robot moves, the bottom of the pool and the trackball fixing plate exert pressure on the trackball, and the trackball and the bottom of the pool generate frictional force, driving the trackball to roll on the plane of the pool surface, reflecting the relative displacement and speed between the underwater robot and the pool surface.

[0082] S340. Reflection from the upper surface of the trackball. The parallel laser beams are reflected by the upper surface of the trackball, generating laser beams with trackball texture information.

[0083] S350. Convergence by the lens module. The laser beams with trackball texture information are converged into concentric laser beams by the convergence sub-module of the lens module and transmitted to the optical sensor module.

[0084] S360. Image array formation. The optical sensor module receives the concentric laser beams converged by the convergence sub-module, converts them into electrical signals proportional to the optical signals, and forms an image array.

[0085] S400, displacement and velocity calculation: The digital signal processing module receives the image array and performs cross-correlation operations. It continuously moves the coordinate position of the latter image array while keeping the former image array fixed, compares the differences between the two image arrays, and when the difference is minimized, determines the variation values in the X-axis and Y-axis directions in terms of pixels between two adjacent image arrays. Through the conversion between pixels and the actual physical distance, displacement and velocity information are obtained;

[0086] S500, navigation information transmission: The digital signal processing module sends the displacement and velocity information to the underwater robot for navigation;

[0087] S600, navigation information response: The underwater robot receives and responds to the displacement and velocity information.

[0088] The above has described in detail the preferred specific embodiments of the present invention. It should be understood that those of ordinary skill in the art can make many modifications and variations based on the concept of the present invention without creative efforts. Therefore, all technical solutions that can be obtained by those skilled in the art in this technical field based on the concept of the present invention through logical analysis, reasoning, or limited experiments on the basis of the prior art should fall within the protection scope determined by the claims.

Claims

1. An underwater robot navigation device with a trackball, characterized in that, Comprising: A trackball, a lens module, an optical sensor module, a laser emission module, a digital signal processing module, and a power management module: The trackball is disposed at the bottom of the underwater robot navigation device and is in direct contact with the surface of the pool. The surface of the trackball is covered with a material suitable for precise laser detection. The parallel laser beam is reflected by the upper surface of the trackball to generate a laser beam with the texture information of the trackball; The lens module consists of a refraction sub-module and a convergence sub-module. The refraction sub-module is disposed above the upper surface of the trackball to enhance the brightness of the concentric laser beam emitted by the laser emission module and refract it into a parallel laser beam, which is incident on the upper surface of the trackball at a certain angle. The convergence sub-module is located above the upper surface of the trackball. The laser beam with the texture information of the trackball reflected by the upper surface of the trackball passes through the convergence sub-module, converges into a concentric laser beam, and then is transmitted to the optical sensor module. The surface area of the trackball illuminated by the parallel laser beam is 5 square millimeters. The refraction sub-module uses a convex lens spherical surface, and the number of reflection planes is one to three, which is selected according to different light guiding schemes. The convergence sub-module uses a circular lens; The optical sensor module is disposed above the convergence sub-module and is provided with uniformly arranged minute photosensitive substances to receive the concentric laser beam converged by the convergence sub-module, convert it into an electrical signal proportional to the optical signal, and form an image array. The size of the image array is 40x40 pixels, and each pixel consists of a gray level in the range of 0-4095. The gray level is determined by the light intensity received at a specific pixel position in the optical sensor module. The optical sensor module is provided with a light transmission hole, and the concentric laser beam converged by the convergence sub-module of the lens module is received through the light transmission hole. The light transmission hole is provided with a waterproof gasket to protect the internal circuit structure; The laser emission module is disposed above the refraction sub-module and emits a concentric laser beam to the upper surface of the trackball; The digital signal processing module includes a digital image chip, is communicatively connected to the optical sensor module, and in response to the image array sent by the optical sensor module, performs a cross-correlation operation to obtain the variation values of the X-axis direction and the Y-axis direction of two consecutive image arrays in units of pixels, and obtains displacement and velocity information through the conversion of pixels and actual physical distances; The power management module is circuit-connected to and supplies power to the laser emission module, the optical sensor module, and the digital signal processing module; The trackball is arranged above the bottom plate of the underwater robot navigation device. The bottom plate is provided with holes for fixing the trackball. Above the bottom plate, there is a fixing plate for applying pressure to the trackball. The trackball is located between the bottom surface of the pool and the fixing plate and is in contact with both. When the underwater robot navigation device moves, the trackball rolls, and the movement of the trackball reflects the movement of the underwater robot navigation device. A waterproof sealing ring is provided at the contact part between the trackball fixing plate and the trackball to prevent water from entering the interior of the navigation device when the trackball rolls, ensuring the safety of the internal circuit. A black bottom plate is provided between the lens module and the power management module, the laser emission module, the optical sensor module, and the digital signal processing module to prevent light interference. Powered by the power management module, the laser emission module emits concentric laser beams. The refraction sub-module of the lens module refracts them into parallel laser beams, which are incident on the upper surface of the trackball at a certain angle. The parallel laser beams reflected by the upper surface of the trackball are converged into concentric laser beams by the converging sub-module of the lens module and transmitted to the optical sensor module to form an image array. The image array is transmitted to the digital signal processing module for cross-correlation operation, and finally displacement and velocity information are obtained.

2. The underwater robot navigation device with a trackball according to claim 1, characterized in that, The material suitable for laser precise detection includes thermoplastic polyurethane.

3. The underwater robot navigation device with a trackball according to claim 1, characterized in that, The certain angle is between 15° and 45°.

4. An underwater robot, characterized in that, The underwater robot navigation device according to any one of claims 1-3 is installed at the bottom of the underwater robot and communicatively connected to receive and respond to the displacement and velocity information of the underwater robot navigation device.

5. An underwater robot navigation method, which uses the underwater robot navigation device with a trackball as described in any one of claims 1-3, is characterized in that, It includes the following steps: S100. Installation of the underwater robot navigation device. The underwater robot navigation device with a trackball is installed at the bottom of the underwater robot. S200. Startup of the underwater robot. The underwater robot is placed in the pool, and the underwater robot and the underwater robot navigation device with a trackball start to work. S300. Image array acquisition. The laser emission module emits concentric laser beams to the upper surface of the trackball. After being reflected and converged by the lens module, an image array is formed in the optical sensor module. The size of the image array is 40x40 pixels, and each pixel consists of a gray level in the range of 0-409,5. The gray level is determined by the light intensity received at a specific pixel position in the optical sensor module, specifically including: S310. Laser emission. The laser emission module emits concentric laser beams to the upper surface of the trackball. S320. Refraction by the lens module. The refraction sub-module of the lens module increases the brightness of the concentric laser beams emitted by the laser emission module and refracts them into parallel laser beams, which are incident on the upper surface of the trackball at a certain angle. The certain angle is between 15° and 45°. S330. When the underwater robot moves, the bottom surface of the pool and the track ball fixing plate exert pressure on the track ball. The track ball generates frictional force with the bottom surface of the pool, driving the track ball to roll on the plane of the pool surface, reflecting the relative displacement and speed between the underwater robot and the pool surface. S340. Reflection from the upper surface of the track ball. The parallel laser beam is reflected by the upper surface of the track ball, generating a laser beam with the texture information of the track ball. S350. Convergence by the lens module. The laser beam with the texture information of the track ball is converged into a concentric laser beam by the converging sub-module of the lens module and transmitted to the optical sensor module. S360. Formation of the image array. The optical sensor module receives the concentric laser beam converged by the converging sub-module, converts it into an electrical signal proportional to the optical signal, and forms an image array. S400. Calculation of displacement and speed. The digital signal processing module receives the image array and performs a cross-correlation operation. Continuously move the coordinate position of the latter frame of the image array, keep the former frame of the image array fixed, compare the difference between the two image arrays. When the difference is the smallest, it is determined as the variation values in the X-axis and Y-axis directions in units of pixels between two adjacent image arrays. Through the conversion between pixels and the actual physical distance, displacement and speed information are obtained. S500. Sending navigation information. The digital signal processing module sends the displacement and speed information to the underwater robot with a track ball for navigation. S600. Response to navigation information. The underwater robot receives and responds to the displacement and speed information.

6. The underwater robot navigation method according to claim 5, wherein, The step S100 includes: S110. Install the underwater robot navigation device with a track ball at the bottom of the underwater robot. The bottom of the underwater robot navigation device with a track ball is close to the bottom of the pool, and the maximum interval shall not exceed 1 mm. S120. Connect the underwater robot navigation device with a track ball and the underwater robot through a USB connection line to transmit navigation data and provide power.

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