Paddle-leg hybrid-driven underwater adhesion robot

Abstract

The invention discloses a paddle-leg hybrid driven underwater adhesion robot, and relates to the technical field of underwater robots, propeller thruster driving, six-foot crawling movement and hydrogel bionic suckers of foot bottom equipment respectively have the advantages of long-distance cruise driving, stable crawling in unstructured terrain and reliable adhesion detection on near wall surfaces. Therefore, the adaptability problem of a single-mode underwater robot in a complex operation scene is solved. According to the invention, the six groups of multi-degree-of-freedom mechanical feet cooperate with the control system through the modular driving units, so that the robot can realize multi-modal motion functions such as seabed crawling, obstacle crossing and climbing, posture adjustment and the like; the robot can stably crawl on a vertical surface or an inverted surface through cooperation between the hydrogel bionic suction cups arranged at the foot ends and the six-foot crawling gaits. Through vector combination of the three vertical propellers and the two horizontal propellers, the robot can meet the multi-degree-of-freedom motion control requirements of advancing, retreating, ascending, sinking, yawing, pitching, pitching and hovering. According to the paddle leg hybrid drive underwater adhesion robot, the underwater hybrid drive potential is developed to the maximum extent, the underwater maneuverability is improved in various challenging underwater environments, and the underwater robot is promoted to develop towards multiple modes and high efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of underwater robots, in particular to an underwater adhesion robot driven by paddles and legs in a hybrid manner. Background Art

[0002] With the growing demand for marine resource development and ecological monitoring, numerous infrastructure and equipment in the aquatic environment have been rapidly constructed and developed, including ships, bridges and dams, offshore platforms and submarine pipelines. Many countries and related industries have established standards for regular inspection, cleaning and maintenance of infrastructure and equipment.

[0003] Traditional underwater robots generally use propeller propulsion systems. Their high propulsion performance and mature navigation algorithms show significant advantages in open waters, such as long-distance cruising and data collection tasks. However, they face significant challenges in complex scenarios: insufficient maneuverability in narrow pipe networks, poor stability in strong flow environments, and reliable detection of vertical or inverted surfaces. Pure legged robots are limited by low hydrodynamic efficiency, weak flow resistance, high energy consumption, and other problems. It is difficult to balance motion efficiency and stability in dynamic flow fields. Therefore, a new underwater robot solution with both terrain adaptability and dynamic stability is urgently needed.

[0004] The integration of underwater robots and bionics is an effective way to overcome the inherent limitations of existing underwater robots. With the complexity of real operating scenarios, multimodal motion has received more and more attention. Combining propeller thrusters with leg-based walking can simultaneously have long-distance cruising and terrain adaptability, which can meet the needs of most underwater tasks. However, some tasks such as hull cleaning, crack detection and damage repair require robots to be tightly attached to the surface of underwater structures to perform delicate small-scale operations, while conventional robots cannot attach to these surfaces. Therefore, it does not meet existing needs. In this regard, we propose an underwater adhesion robot driven by a paddle-leg hybrid. Summary of the invention

[0005] The purpose of the present invention is to provide an underwater adhesion robot with propeller drive and six-legged crawling multi-modal motion capabilities. It adopts propeller propeller drive for long-distance cruising missions, and six-legged crawling motion in unstructured terrains such as submarine pipelines. For reliability inspection tasks that require close adhesion to surfaces or even vertical or inverted surfaces, the hydrogel bionic suction cup at the bottom of the six legs is activated, aiming to improve the problem that existing underwater robots cannot adapt to diversified operation tasks in complex scenarios.

[0006] In order to solve the above technical problems, the present invention is implemented through the following technical solutions: an underwater adhesion robot driven by a paddle and legs, including a robot body, an electronic sealed cabin and a pressure sensor are arranged inside the body, three vertical thrusters are arranged on both sides of the front and rear of the body, a horizontal thruster is arranged on both sides of the rear of the body, two LED searchlights and a camera are arranged on the head of the body, a cable communication interface is arranged at the tail of the body, and six groups of leg crawling mechanisms are symmetrically distributed on the outside of the body.

[0007] The above-mentioned electronic sealed cabin includes all electronic components for controlling the movement of the robot. The electronic components include a Raspberry Pi as a main controller, which is used to send movement instructions and communicate with a host computer, and a PCA9685 control board and a flight controller as slave controllers. The PCA9685 is used to send control instructions to drive six groups of 18 waterproof servos in the legs and diaphragm pumps in the legs for controlling hydrogel bionic suction cups. The flight controller is used to send instructions to drive three vertical thrusters and two horizontal thrusters. The flight controller includes a gyroscope and an accelerometer for measuring the robot's posture and acceleration information. The electronic components also include an electronic speed regulator, an LED driver board and a power module. The electronic speed regulator is used to convert the control signal sent by the flight controller into a digital signal to drive a brushless motor. The LED driver board is used to control the LED searchlight on the head of the main body, and the power module is used to supply power to all components of the robot.

[0008] The pressure sensor is installed directly below the robot body and is used to measure the depth information of the robot in water.

[0009] Preferably, three vertical thrusters are fixed to the robot's outer shell by bolts, and are composed of a 930kv brushless motor and a propeller. The vertical thrusters achieve rising and sinking movements by rotating at the same speed and in the same direction, and achieve pitching movements by rotating in the opposite directions at the same speed. The tumbling movement is achieved by the reverse movement of the vertical thrusters on both sides in front of the main body.

[0010] Preferably, the horizontal thrusters on both sides of the robot body are fixed to the robot outer shell through a base, and are composed of a 980kv brushless motor and a propeller. The horizontal thrusters achieve forward and backward movement by rotating at the same speed and in the same direction, and the vertical thrusters achieve turning movement by rotating in the opposite direction at the same speed.

[0011] Preferably, the LED searchlight is fixed to the robot head by bolts, and the searchlight is composed of a 5W LED lamp bead and a waterproof focusing lens, and the waterproof function is achieved by epoxy resin casting.

[0012] Preferably, the camera is fixed to the robot head by bolts, and the camera parameters are 1080P high-definition USB camera module, 3.6mm focal length lens, 90-degree viewing angle, and the camera is placed in a small sealed cabin and waterproofed by epoxy resin casting.

[0013] Preferably, the cable communication interface is fixed to the tail of the robot by bolts, and the communication interface consists of a WF16-10 core waterproof socket, and the waterproof function is achieved by sealing ring and epoxy resin casting.

[0014] Preferably, the leg crawling mechanism is symmetrically fixed to the outside of the robot body by bolts, and the leg crawling mechanism consists of three joints, and the sizes of the three joints are 48mm, 76mm, and 147mm respectively. The joints are driven by three IPX8 waterproof digital servos respectively. A diaphragm pump is provided inside the third joint of the crawling mechanism, and the diaphragm pump is waterproofed by epoxy resin casting. A hydrogel bionic suction cup is provided at the foot end of the crawling mechanism, and the hydrogel bionic suction cup is prepared by Zr4+ coordinated hydrogel printed by digital light processing 3D printing. The hydrogel has improved mechanical strength and anti-expansion performance through a double-network toughening strategy, and a connecting circuit is added inside the hydrogel suction cup, and the adhesion and detachment functions of the suction cup are realized by opening and closing the diaphragm pump.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] 1. The underwater robot disclosed in the present invention has the ability to adapt to all terrains in narrow spaces in the six-legged crawling mode. The bionic joint structure of the underwater robot is designed based on the bionic principles of enhancing stability and optimizing contact force distribution. The six sets of multi-degree-of-freedom mechanical feet cooperate with the modular drive unit and the control system to enable the robot to achieve multi-modal motion functions such as seabed crawling, obstacle climbing, and posture adjustment. This mode can be applied to complex seabed terrain exploration, equipment inspection and maintenance, and other refined operation tasks.

[0017] 2. The hydrogel bionic suction cup equipped at the foot end of the underwater robot disclosed in the present invention has the ability to stably adhere to the surface of the underwater structure. The hydrogel suction cup is internally provided with a connecting circuit, and the adhesion and detachment functions are realized by opening and closing the diaphragm pump. Combined with the gait design in the six-legged crawling mode and the coordinated cooperation of the diaphragm pump, the robot can achieve stable crawling on vertical or inverted surfaces. This mode can be applied to near-wall operation tasks such as hull cleaning, crack detection and damage repair.

[0018] 3. The underwater robot disclosed in the present invention has 5-degree-of-freedom motion control capability under propeller drive mode. The streamlined appearance of the underwater robot and the configuration and installation of the thrusters are designed based on the principles of reducing water resistance and improving space utilization. The vector combination arrangement of three vertical thrusters and two horizontal thrusters enables the robot to meet the requirements of forward, backward, ascent, sinking, bow roll, pitch, roll, and hovering multi-degree-of-freedom motion control. This mode is suitable for tasks such as long-distance cruising and data collection. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0020] Figure 2 A top view of the present invention as a whole;

[0021] Figure 3 It is a schematic diagram of a single-leg three-dimensional structure of the present invention;

[0022] Figure 4 It is a schematic diagram of the three-dimensional structure of the hydrogel bionic suction cup of the present invention;

[0023] Figure 5 It is a schematic diagram of the structure of the vertical propeller thruster of the present invention;

[0024] Figure 6 It is a schematic diagram of the structure of the horizontal propeller thruster of the present invention;

[0025] Figure 7 It is a schematic diagram of the IPX8 waterproof steering gear structure of the present invention.

[0026] In the figure: front shell 1, rear shell 2, leg-type walking mechanism 3, vertical propeller thruster 4, horizontal propeller thruster 5, communication cable interface 6, left LED light 701, right LED light 702, camera 8, left front leg 901, right front leg 902, left middle leg 903, right middle leg 904, left hind leg 905, right hind leg 906, left front vertical thruster 1001, right front vertical thruster 1002, rear vertical thruster 1003, left horizontal thruster 1101, right horizontal thruster 1102, first leg joint 1201, second leg joint 1202, third leg joint 1203, first joint waterproof steering gear 1301, second joint waterproof multi-stage 1302, third joint waterproof steering gear 1303, A joint connecting plate 14, a diaphragm pump 15, a hydrogel suction cup 16, a suction cup top base 1701, a suction cup internal communication circuit 1702, a pillar 1703, a suction cup bottom base 1704, a suction cup bionic array foot 1705, a vertical propeller base 1801, a motor rotating shaft 1802, a vertical propeller fixing shaft 1803, a vertical propeller fixing hole 1804, a 930kv waterproof brushless motor 1805, a propeller fixing base 1901, a horizontal propeller outer shell 1902, a horizontal propeller fixing hole 1903, a motor rotating shaft 1904, a 980kv waterproof brushless motor, an IPX8 waterproof servo 2001, a horizontal propeller fixing hole 2002, a horizontal propeller fixing bolt 2003, and a servo output shaft 2004. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. It should be pointed out that the specific implementation methods described here are only used to explain and illustrate the present invention and are not used to limit the present invention.

[0028] Embodiment 1: Figure 1 to Figure 2 The following is an example of the appearance of the underwater robot. Figure 1 to Figure 2The electronic sealed cabin inside the robot is omitted to illustrate the main structural components in a concise and clear manner. The underwater robot includes a front shell 1, a rear shell 2, a leg-type walking mechanism 3, a vertical propeller thruster 4 and a horizontal propeller thruster 5, wherein the front shell 1 and the rear shell 2 are fixed by internal connectors; the cable communication interface 6 is fixed to the tail of the main body by bolts, and the left LED light 701, the right LED light 702, and the camera 8 are fixed to the head of the main body by bolts; the leg-type walking mechanism is composed of six-legged three-degree-of-freedom crawling legs, wherein the left front leg 901, the right front leg 902, the left middle leg 903, the right middle leg 904, the left rear leg 905, and the right rear leg 906 are symmetrically distributed outside the robot body; the left front vertical thruster 1001, the right front vertical thruster 1002, and the rear vertical thruster 1003 are fixed to the robot body by bolts, and the left horizontal thruster 1101 and the right horizontal thruster 1102 are fixed to the robot body through a base, and the vector combination of the five thrusters realizes the multi-degree-of-freedom motion control of the robot in the swimming mode. The robot has three main motion modes:

[0029] A. Six-legged crawling mode is suitable for complex seabed terrain exploration, equipment maintenance and other refined operation tasks;

[0030] B. Hydrogel suction cup adhesion crawling mode, suitable for near-wall operations such as hull cleaning and damage repair;

[0031] C. Propeller drive mode, suitable for long-distance cruising and data collection tasks.

[0032] Embodiment 2: Figures 2 to 3 The following example is used to explain the working principle of the underwater robot in the crawling motion mode. When the upper computer decision layer selects the six-leg crawling mode, the main controller Raspberry Pi simulates the biological neural rhythm through the central pattern generator based on the Hopf oscillator, outputs the foot-end target trajectory of the six sets of legs, and the six sets of legs swing through the first joint 1201 to achieve stepping, the second joint 1202 adjusts the leg lifting height, and the third joint 1203 keeps the foot end moving horizontally. The Raspberry Pi solves the 18 joint angles of the six sets of legs in real time through inverse kinematics, and converts the joint angles into the PWM duty cycle of the PCA9685, and transmits the PWM duty cycle to the GPIO of the Raspberry Pi. 2 C interface sends PWM register value to PCA9685, and the slave controller PCA9685 outputs 50Hz PWM signal to the corresponding servo according to the received duty cycle parameter. The 16-channel PWM output is used to control 18 joints of six groups of legs in parallel through I 2 C bus batch writes registers to reduce single communication delays, detects the fuselage posture through the fuselage's built-in inertial measurement unit, adjusts the support leg joint angles to maintain balance, and continuously generates periodic signals based on the central pattern generator to achieve continuous crawling.

[0033] Embodiment 3: Figure 3 to Figure 4 The working principle of the underwater robot in the adhesion crawling mode is explained as an example. When the upper computer decision layer selects the adhesion crawling mode, the main controller Raspberry Pi realizes adhesion and desorption during the crawling process by collaboratively controlling the six-legged legs and the hydrogel bionic suction cup. The diaphragm pump 15 provides negative pressure (exhaustion during adsorption) and positive pressure (inflation during desorption), and the hydrogel suction cup 16 realizes surface adhesion through the negative pressure principle. The MOSFET drive module adjusts the start and stop and direction of the diaphragm pump. During the robot crawling process, before the foot end enters the support phase (touching the ground and bearing weight), the diaphragm pump is started to pump air into the suction cup for negative pressure adhesion. Before the foot end enters the swing phase (lifting the leg to move), the diaphragm pump is switched to inflate the suction cup for desorption. The main control end Raspberry Pi generates the crawling gait and the diaphragm pump opening and closing signal integration and sends it to the slave controller. The slave control end PCA9685 and MOSFET are driven in parallel to ensure the synchronous update of the adhesion signal and the joint PWM, and realize stable adhesion crawling on vertical or inverted surfaces.

[0034] Embodiment 4: Figures 5 to 7 The following is an example to explain the working principle of the underwater robot in the propeller drive mode. When the upper computer decision layer selects the propeller drive mode, the main controller Raspberry Pi generates control instructions according to the trajectory planning algorithm or upper layer input, communicates with the flight controller through the MAVLink protocol, receives the main control instructions from the controller flight control and parses them into motor speed instructions, which are parsed into digital signals by the electronic speed regulator to control the rotation of the brushless motor. The brushless motor rotating shaft 1802 is fixed with propeller blades to drive the robot to move. The robot adjusts the body posture and depth in real time through the inertial measurement unit and depth sensor of the body. The flight controller updates the motor speed every 20ms to dynamically adjust the body movement direction, and realizes multi-degree-of-freedom motion control through the vector combination of five thrusters.

[0035] The above embodiments are only for illustrating the inventive concept and features of the present invention, and their purpose is to enable ordinary technicians in the field to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. All equivalent changes or modifications made based on the essence of the content of the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of this application shall be based on the protection scope of the claims.

Claims

1. An underwater adhesion robot driven by paddle and legs, comprising a robot body, a six-legged crawling mechanism, a propeller thruster system, a hydrogel bionic suction cup, an electronic sealed cabin and a sensor module, characterized in that: Six groups of leg crawling mechanisms are symmetrically distributed outside the robot body, each group of leg crawling mechanisms includes three joint-driven mechanical legs, and a hydrogel bionic suction cup is provided at the foot end; The thruster system includes three vertical thrusters and two horizontal thrusters, the vertical thrusters are arranged on both sides of the front and rear of the robot body, and the horizontal thrusters are arranged on both sides of the rear of the robot body; The electronic sealed cabin integrates a main controller, a slave controller and a power module. The main controller is a Raspberry Pi, which is used for multi-modal motion decision-making and trajectory planning; the slave controller includes a PCA9685 control board and a flight controller, which respectively drive the leg servos and thruster motors; The robot has the following three motion modes: Hexapod crawling mode: Generate periodic gait through the central pattern generator and control the leg joint servos to achieve crawling operation; Hydrogel suction cup adhesion crawling mode: The negative pressure adsorption and desorption of the hydrogel bionic suction cup are controlled by a diaphragm pump, and the hexapod gait is coordinated to achieve stable crawling on vertical or inverted surfaces; Propeller drive mode: Multi-degree-of-freedom movement is achieved through the vector combination of vertical and horizontal propeller thrusters.

2. The underwater adhesion robot according to claim 1, characterized in that: The sizes of the three joints of the hexapod crawling mechanism are 48mm, 76mm, and 147mm respectively, and each joint is driven by an IPX8 waterproof digital servo. A diaphragm pump is integrated inside the third joint, and waterproof sealing is achieved by epoxy resin casting.

3. The underwater adhesion robot according to claim 1, characterized in that: The hydrogel bionic suction cup is 3D printed with Zr 4 ⁺ Coordinated double network hydrogel preparation, a connecting circuit is set inside the suction cup, and the adhesion and desorption functions are realized by the vacuum and inflation of the diaphragm pump; the diaphragm pump is controlled by a MOSFET module, and the adsorption action is synchronized with the hexapod gait phase, the support phase starts the adsorption, and the swing phase triggers the desorption.

4. The underwater adhesion robot according to claim 1, characterized in that: The vertical thruster is driven by a 930kv brushless motor, and realizes rising / sinking movement through constant speed and same direction rotation, and realizes pitching / rolling movement through constant speed and opposite direction rotation; the horizontal thruster is driven by a 980kv brushless motor, and realizes forward / backward movement through constant speed and same direction rotation, and realizes bow rolling movement through differential rotation.

5. The underwater adhesion robot according to claim 1, characterized in that: The PCA9685 control board receives the main controller command through the I²C protocol, and outputs 16 PWM signals to drive 18 waterproof servos on six groups of legs; the flight controller receives the main controller command through the MAVLink protocol, analyzes it into a motor speed signal, and drives the brushless motor through the electronic speed regulator.

6. The underwater adhesion robot according to claim 1, characterized in that: The sensor module includes an inertial measurement unit, a depth sensor and a foot contact switch; the inertial measurement unit is used to provide real-time feedback on the robot's posture, the depth sensor is used to measure the robot's underwater depth, and the foot contact switch is used to trigger adsorption / desorption actions. The robot head is equipped with a 1080P high-definition camera and dual LED searchlights, and the camera and LED lights are sealed by epoxy resin casting; the robot tail is equipped with a WF16-10 core waterproof communication interface, which supports cable data transmission.

7. The multi-modal motion control method of the underwater adhesion robot according to claims 1 to 6, characterized in that The following steps are involved: Select the motion mode according to the task requirements and generate the corresponding control commands through the main controller Raspberry Pi; In the hexapod crawling mode, a periodic gait signal is generated by the central pattern generator network and sent to the PCA9685 control board to drive the servo to perform the joint angle obtained by the real-time solution of inverse kinematics; In the adhesion crawling mode, the gait phase is coordinated with the diaphragm pump action, the support phase starts the adsorption, the swing phase triggers the desorption, and the body posture is adjusted in real time through the inertial measurement unit; In the propeller thruster drive mode, the speed of each thruster is distributed through the flight controller, and converted into digital signals by the electronic speed regulator to drive the brushless motor to rotate, realizing multi-degree-of-freedom motion control.

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