Structural design, paddling gait planning, and testing device of a bionic canine amphibious robot

Abstract

The present invention discloses a structural design, paddling gait planning and testing device of a bionic canine amphibious robot, belonging to the technical field of amphibious robots. The present invention uses the principle of bionics to allow the robot to imitate the gait of mammals in nature to achieve faster and more efficient movement in a water environment. The proposal of this gait is more scientific and reasonable, and does not require additional propulsion devices or deformation devices to achieve movement in land and water environments. The mechanical structure is simple and some sandwich waterproof structures are added. The present invention can directly obtain the numerical value of the force applied to the object under test during underwater movement, can measure the numerical value of the force in two opposite directions, and can measure the force in other directions by only changing the connection direction of the aluminum profile. The degree of integration is good. When the gait of the robot during underwater movement is changed, the force measuring device can still accurately measure the force applied, and has good adaptability.

Description

Technical Field

[0001] The present invention relates to the structural design and paddling gait planning of a bionic dog amphibious robot, and in particular to the structural design, paddling gait planning and testing device of a bionic dog amphibious robot, belonging to the technical field of amphibious robots. Background Art

[0002] After a long evolutionary process, animals in nature have developed excellent adaptability to complex natural environments. For example, in order to survive and hunt, agile mammals such as canines and felines have demonstrated much better terrain adaptability in the wild environment. This is due to their special body structure and movement gait. These characteristics have attracted widespread attention from robotics researchers. The four-legged robots designed to imitate canines and felines, such as ANYmal, MITCheetah, HyQReal, SPOTmini, Jueying and UnitreeRobot, have become more mature in structure and design, and some have even been commercialized. These mammal-inspired quadruped robots By integrating reinforcement learning and other intelligent motion control algorithms, quadruped robots can imitate real mammals in nature and walk and move in complex terrains such as grass, mud, snow and sand, maintaining good balance and maneuverability. They have demonstrated great value in application scenarios such as field search and rescue and inspection services. Although these bionic quadruped robots have excellent performance on land, there is a relative lack of research on their propulsion mechanisms and mechanical models for movement in water. When performing field search and rescue and exploration missions, robots often face challenges from changing climates and diverse geological environments, especially complex aquatic and terrestrial environments, such as small rivers and lakes. The lack of movement ability in water will become an obstacle to their mission execution.

[0003] At the same time, with the development of industrial technology, the requirements for robot motion stability and controllability are becoming increasingly higher, but the force conditions of robots during movement in underwater environments are usually difficult to calculate or directly measure through existing sensing technologies.

[0004] Most existing robots that can achieve amphibious functions use two sets of propulsion devices to propel themselves in water and land environments respectively.

[0005] For example, patent CN202110998674.5 proposes a multi-terrain amphibious robot with wheels and fins. The robot uses a wheel structure for land propulsion on land and a flexible fin surface for propulsion underwater. That is, there are two sets of propulsion devices to propel the robot in the water and land environment respectively. This increases the complexity of the robot's mechanical structure and motion control, and the propulsion force generated by the flexible fin surface is relatively small. At the same time, the force conditions of the robot in the water are not analyzed.

[0006] The patent CN112265420B only uses one set of propulsion devices for simultaneous propulsion in water and land environments. The robot uses a composite crank rocker slider mechanism as a propulsion mechanism, which can walk on land and swing in water to provide thrust, allowing the robot to quickly switch between water and land environments, and effectively solves the problem of propellers being easily damaged in water. However, the water gait used in this invention is relatively simple and is not based on the principles of bionics. It does not have high movement efficiency, but the force conditions of the robot in water are not analyzed.

[0007] Another example is patent CN113459738B, which includes a support frame, an electronic control component, a sealed shell, a floating leg and a flexible web driving module. The four floating legs are arranged in a centrally symmetrical manner on the front and rear sealing cover plates of the sealed shell. A flexible web driving module is provided at the calf of each floating leg. The web flexible driving module is arranged in the sealed shell of the robot, and the driving force is transmitted to the web mechanism through a flexible rope to control the floating leg to switch between the foot form and the web form, so that it can maintain the ability of the leg robot to move on land and obtain the ability to dive or walk underwater. However, the patent still does not analyze the force conditions generated by the proposed underwater movement scheme, and the structural design mentioned is based on the adjustment of the web structure, and does not have the structural universality of the current quadruped robot.

[0008] Deficiencies in the existing technology:

[0009] Most existing amphibious robots use two sets of propulsion devices or deformation devices to achieve movement in water environments and land environments respectively, which increases the complexity of the mechanical structure and the complexity of the control algorithm. Even if some robots can achieve movement in water and land environments using only one device, their gait in water is not flexible enough and their movement efficiency is not high.

[0010] Existing methods for calculating the underwater forces of amphibious robots can be roughly divided into three categories: theoretical calculation, finite element simulation, and actual measurement. Since the hydrodynamic formula acting on the legs during paddling is related to speed, the first-order differential kinematics of the robot show that the movement speed of each leg element is related to its position on the leg. Therefore, the leg hydrodynamics during paddling involves integral calculations, which makes theoretical calculations too difficult. Although the Fluent finite element simulation method is desirable, the underwater forces acting on the quadruped robot are too complex, resulting in a long calculation time. In addition, the finite element simulation method cannot clearly describe the connection relationship between the joints, resulting in inaccurate transmission of the hydrodynamic force of the entire robot. Therefore, by building an actual measurement device, the forces acting on the individual legs and the entire robot during underwater motion can be clearly and effectively obtained. However, existing technologies lack direct measurement methods. In most cases, the force conditions can only be obtained indirectly, such as measuring the robot's posture information through an IMU, estimating the quadruped's current state information, and combining it with the dynamic model to calculate the robot's force conditions. This places high demands on the accuracy of the model establishment and the method is relatively complex.

[0011] Therefore, a bionic canine amphibious robot with structural design, paddling gait planning and testing equipment is needed to improve the above-mentioned deficiencies. Summary of the Invention

[0012] The main purpose of the present invention is to provide a structural design, paddling gait planning and testing device for a bionic canine amphibious robot.

[0013] The purpose of the present invention can be achieved by adopting the following technical solutions:

[0014] A bionic canine amphibious robot structural design, paddling gait planning, and testing device includes a body lower cover for limiting position, which is mounted on the amphibious quadruped robot. A calf cover 1, a calf cover 2, a knee joint motor, a thigh cover 2, a thigh cover 1, and a hip joint motor are mounted on both sides of the body lower cover on a thigh cover 2, which move alternately in correspondence.

[0015] Hip joint motors are symmetrically installed on both sides of the lower cover of the fuselage. The output end of the hip joint motor is installed with thigh cover 1, the outer side of thigh cover 1 is covered with thigh cover 2, and the inner side of thigh cover 2 and the end of thigh cover 1 are installed with knee joint motors.

[0016] The output end of the knee joint motor is provided with a calf cover 2, and the outer side of the calf cover 2 is covered with a calf cover 1;

[0017] The lower cover of the fuselage, thigh cover 1, thigh cover 2, knee joint motor, calf cover 2 and calf cover 1 are covered with waterproof components;

[0018] An operating module assembly is installed in the lower cover of the fuselage;

[0019] A guide limit assembly is installed on the lower cover of the fuselage.

[0020] Preferably, the lower cover of the fuselage is correspondingly covered with the upper front cover and the upper rear cover of the fuselage, the upper rear cover is equipped with a power switch, and the upper front cover and the upper rear cover are respectively equipped with a code burning port and a charging port.

[0021] Preferably, the waterproof component includes a fuselage lower cover interlayer, a hip joint fixing interlayer, a calf cover interlayer, a fuselage upper cover interlayer, a thigh cover interlayer and a single chip computer;

[0022] The fuselage lower cover interlayer is installed around the inner side of the fuselage lower cover, the fuselage upper cover interlayer is installed around the inner and outer circles of the fuselage front cover and the fuselage rear cover shells, the thigh cover interlayer is installed at the joint between the inner side of the thigh cover two and the thigh cover one, the hip joint fixing interlayer one is installed at one end of the fuselage lower cover, and a single-chip computer is installed on the right side of the hip joint fixing interlayer one, the calf cover interlayer is installed at the joint between the inner side of the calf cover two and the calf cover one, and the fuselage lower cover interlayer and the fuselage upper cover interlayer are fitted and connected to each other.

[0023] Preferably, the operation module assembly separates the communication module, and the communication module is installed on one side of the single chip microcomputer in the lower cover of the fuselage.

[0024] Preferably, the guide and limit assembly includes a quadruped robot fixing frame, a guide rail, a slide rail support plate, a sensor connector 1, a force sensor, an upper sensor fixing frame, a lower sensor fixing frame, a profile and a small slider;

[0025] The outer side of the amphibious quadruped robot is clamped and installed with a quadruped robot fixing frame, and the upper end of the quadruped robot fixing frame is installed with a slide rail support plate, and the upper sensor fixing frame and the lower sensor fixing frame are symmetrically installed on both sides of the slide rail support plate. A sensor connector and a force sensor are installed between the upper sensor fixing frame and the lower sensor fixing frame. The slide rail support plate is sleeved on the profile, and the small slider is flipped on the guide rail. The guide rail is fixed to the slide rail support plate by screws and nuts. The slide rail support plate is clamped on the profile by screws and nuts. Guide rails are installed on both sides of the slide rail support plate, and the upper sensor fixing frame and the lower sensor fixing frame are adjusted and connected along the guide rails.

[0026] Preferably, thigh cover 1 and thigh cover 2 are assembled and the knee joint motor is fixed using the reserved holes at both ends.

[0027] Preferably, the small slider and the quadruped robot fixing frame move up and down with the amphibious quadruped robot, and the lower cover of the fuselage, the front cover of the fuselage and the rear cover of the fuselage are sealed by the first waterproof glue coating point and the second waterproof glue coating point.

[0028] Preferably, the amphibious quadruped robot is connected by linear motion along the guide rail under the action of water power.

[0029] Preferably, the calf cover 1, calf cover 2, knee joint motor, thigh cover 2, thigh cover 1 and hip joint motor of the amphibious quadruped robot are symmetrical on both sides and form a structure that moves alternately with one side forward and the other side backward.

[0030] A method for testing the structural design and paddling gait planning of a bionic canine amphibious robot, based on the structural design and paddling gait planning testing device of a bionic canine amphibious robot according to claims 1-9, further comprising the following steps:

[0031] Step 1: The profiles are connected vertically using die-cast aluminum angles and then bolted together. Two slide rail support plates are screwed together and then wrapped around the aluminum profiles. The guide rails are placed on top of the support plates and fit into the grooves of the smooth small sliders. Two quadruped robot mounting brackets are screwed together, with the upper support surface placed on the small sliders and the large grooves at the lower ends used to clamp the amphibious quadruped robot body.

[0032] Step 2: The clamping plate and slider can follow the robot's forward movement. The rear end of the quadruped robot's fixed frame is first fixed with a sensor fixing piece by screws. The sensor connector and the connecting piece are then fixed in the axial direction by cylindrical pins. A force sensor is clamped between the sensor connecting piece and the sensor fixing frame. The groove of the sensor fixing frame is also stuck on the guide rail, and the fixing frames are fastened with screws.

[0033] Step 3: Sensor Connections 1. The force sensor, upper sensor bracket, and lower sensor bracket follow the up-and-down motion of the amphibious quadruped robot, rather than measuring the forward and backward motion of the drag force. The connection method for measuring thrust and drag is the same, with only the profile and splint mounting methods changing. The quadruped robot's shell is 3D-printed from PLA, and the leg's rotary joints are constructed with waterproof motors.

[0034] Step 4: When the legs of the amphibious quadruped robot are subjected to thrust or resistance while moving underwater, the small slider and the grooves of the sensor's lower fixing frame are smooth enough. Therefore, under the action of hydrodynamic force, the quadruped robot drives the plywood, fixing frame, and connectors supported by the aluminum profile to move linearly along the guide rail. The upper fixing frame of the sensor is completely stuck, while the lower fixing frame of the sensor is movable. The strain sensor measures the force through the change in strain, so one end is stuck and the other end is movable. That is, one end of the sensor is fixed to the upper fixing frame of the sensor, and the other end connected to the lower fixing frame of the sensor is movable.

[0035] The profile, sensor, upper sensor mounting bracket, slide rail, and guide rail support plate are all fixed, while the amphibious quadruped robot, quadruped robot mounting bracket, sensor lower mounting bracket, and connector will move on the slide rail according to the force applied to them.

[0036] Step 5: Since the force sensor is clamped by the sensor connector 1, the upper sensor bracket, and the lower sensor bracket, when the robot moves forward, the force sensor can measure the thrust provided by the bracket, which is the total thrust experienced by the paddling. When the amphibious quadruped robot moves backward, the force sensor can measure the thrust provided by the sensor connector, which is the total resistance experienced by the paddling.

[0037] Step 6: When the amphibious quadruped robot is subjected to force, it drives the quadruped robot fixing frame and the sensor lower fixing frame to move on the small slider, thereby changing the strain of the sensor. The thrust is the lift force exerted on the amphibious quadruped robot when paddling. When the force is downward, the force sensor detects that the thrust of the sensor upper fixing frame and the sensor lower fixing frame is the negative lift force exerted on the robot when paddling. Comparing the two force measuring devices, it can be found that only by modifying the installation method of the aluminum profile and the installation method of the splint, it can be found that the force conditions in multiple directions can be measured.

[0038] Beneficial technical effects of the present invention:

[0039] The present invention provides a structural design, paddling gait planning and testing device for a bionic canine amphibious robot.

[0040] 1) To address the shortcomings of current amphibious robots, which have complex propulsion structures or require deformable structures to achieve propulsion in amphibious environments, this invention does not require additional propulsion devices and uses the same propulsion device to achieve movement both on land and underwater. That is, the terrestrial quadruped robot uses the foot end to support the ground and the legs to swing alternately to move forward, while the quadruped robot relies on the paddling movement of the legs to propel itself in water, without the need for additional propulsion devices or deformable devices;

[0041] 2) To achieve underwater locomotion for quadruped robots, based on bionic principles, two paddling gaits were proposed: Lateral-Sequence Padding Gait (LSPG) and Trot-Like Padding Gait (TLPG). These two proposed gaits have their own advantages and disadvantages and are suitable for different environments. The gait that meets the locomotion requirements can be selected based on the specific conditions of the current environment. For example, when the water surface is calm, the LSPG gait, which is faster but less stable, can be selected. When the water surface is choppy and the robot needs to move more stably through the river, the LSPG gait can be selected.

[0042] 3) This invention leverages bionic principles to allow the robot to mimic the gait of mammals in nature, achieving faster and more efficient aquatic locomotion. This gait is more scientific and rational, requiring no additional propulsion or deformation devices to enable locomotion in both terrestrial and aquatic environments. The mechanical structure is simple, and compared to existing quadruped robots, it incorporates a sandwich-type waterproof structure.

[0043] 4) Compared with the existing technology, the present invention can directly obtain the numerical value of the force exerted on the object under test when it moves underwater, without the need for the additional calculation and fitting steps required by the stiffness calculation method proposed by the existing patent. At the same time, the numerical value of the force in two opposite directions can be measured at a time, and only the connection direction of the aluminum profile is changed to measure the force in other directions. The degree of integration is good. When the gait of the robot moving underwater is changed, the force measuring device can still accurately measure the force exerted, and has good adaptability. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 A schematic diagram of a quadruped robot leg assembly according to a preferred embodiment of the structural design, paddling gait planning and testing device of a bionic canine amphibious robot of the present invention;

[0045] Figure 2 A schematic diagram of a quadruped robot interface according to a preferred embodiment of the structural design, paddling gait planning and testing device of a bionic canine amphibious robot of the present invention;

[0046] Figure 3 A schematic diagram of a quadruped robot body assembly according to a preferred embodiment of the structural design, paddling gait planning and testing device of a bionic canine amphibious robot of the present invention;

[0047] Figure 4 A schematic diagram of a waterproof quadruped robot structure according to a preferred embodiment of the structural design, paddling gait planning and testing device of a bionic canine amphibious robot of the present invention;

[0048] Figure 5 A side view of a drag and thrust measuring device according to a preferred embodiment of the structural design, paddling gait planning, and testing device of a bionic canine amphibious robot of the present invention;

[0049] Figure 6 A front view of a drag force and thrust measurement device according to a preferred embodiment of a structural design, paddling gait planning, and testing device for a bionic canine amphibious robot of the present invention;

[0050] Figure 7Detailed assembly diagram of a drag and thrust measuring device according to a preferred embodiment of the structural design, paddling gait planning, and testing device for a bionic canine amphibious robot of the present invention;

[0051] Figure 8 Detailed assembly diagram of a drag and thrust measuring device according to a preferred embodiment of the structural design, paddling gait planning, and testing device for a bionic canine amphibious robot of the present invention;

[0052] Figure 9 Detailed assembly diagram of a lift and drag measuring device according to a preferred embodiment of the structural design, paddling gait planning, and testing device for a bionic canine amphibious robot of the present invention;

[0053] Figure 10 A side view of a lift and drag measurement device according to a preferred embodiment of the structural design, paddling gait planning, and testing device for a bionic canine amphibious robot of the present invention;

[0054] Figure 11 Figure 1 shows a preferred embodiment of a bionic canine amphibious robot structure design, paddling gait planning, and testing device according to the present invention: (a) a phase diagram of the limbs of a real canine mammal swimming and paddling; (b) a schematic diagram of the robot's leg paddling during the Power Phase; and (c) a schematic diagram of the robot's leg paddling during the Recovery Phase.

[0055] Figure 12 Schematic diagram of the stages of a quadruped robot's paddling gait according to a preferred embodiment of the structural design, paddling gait planning and testing device of a bionic canine amphibious robot of the present invention;

[0056] Figure 13 (a) The Lateral-SequencePaddingGait proposed in a preferred embodiment of the structural design, paddling gait planning, and testing device for a bionic canine amphibious robot according to the present invention is derived from the paddling motion of canine mammals; (b) The Trot-LikePaddingGait gait limb phase diagram proposed in the present invention is derived from the paddling motion of mink mammals;

[0057] Figure 14 A schematic diagram of a canine mammal's paddling limb motion according to a preferred embodiment of the structural design, paddling gait planning, and testing device for a bionic canine amphibious robot of the present invention;

[0058] Figure 15Schematic diagram of the fitting of 12 key positions using Fourier functions according to a preferred embodiment of the structural design, paddling gait planning and testing device of a bionic canine amphibious robot of the present invention, (a) the fitting case where PowerPhase accounts for 50%, and (b) the fitting case where PowerPhase accounts for 25%.

[0059] In the figure: 1. Quadruped robot fixing frame; 2. Guide rail; 3. Slide rail support plate; 4. Amphibious quadruped robot; 5. Sensor connector 1; 6. Force sensor; 7. Sensor upper fixing frame; 8. Sensor lower fixing frame; 9. Profile; 10. Small slider; 11. Calf cover 1; 12. Calf cover 2; 13. Knee joint motor; 14. Thigh cover 2; 15. Thigh cover 1; 16. Hip joint motor; 17. Body lower cover; 18. Waterproof glue application point 1; 19. Power switch; 20. Code burning port; 201. Charging port; 21. Body front cover; 22. Body rear cover; 23. Waterproof glue application point 2, 24. Body lower cover interlayer; 25. Communication module; 26. Hip joint fixing interlayer; 27. Calf cover interlayer; 28. Body upper cover interlayer; 29. ​​Thigh cover interlayer; 30. Single chip microcomputer. DETAILED DESCRIPTION

[0060] In order to make the technical solution of the present invention more clear and specific to those skilled in the art, the present invention is further described in detail below with reference to embodiments and drawings, but the embodiments of the present invention are not limited thereto.

[0061] like Figure 1 - Figure 10 As shown, the present embodiment provides a structural design, paddling gait planning, and testing device for a bionic canine amphibious robot, comprising a body lower cover 17 for limiting position, which is mounted on the amphibious quadruped robot 4. A calf cover 11, a calf cover 2, 12, a knee joint motor 13, a thigh cover 2, 14, a thigh cover 15, and a hip joint motor 16 are mounted on both sides of the body lower cover 17 on the thigh cover 2, which are alternately movable.

[0062] Hip joint motors 16 are symmetrically mounted on both sides of the lower cover 17 of the body. Thigh cover 15 is mounted on the output end of the hip joint motor 16. The outer side of thigh cover 15 is covered by thigh cover 2 14. The inner side of thigh cover 2 14 and the end of thigh cover 1 15 are mounted with knee joint motors 13.

[0063] The output end of the knee joint motor 13 is installed with a calf cover 2 12, and the outer side of the calf cover 2 12 is covered with a calf cover 1 11;

[0064] The body lower cover 17, thigh cover 1 15, thigh cover 2 14, knee joint motor 13, calf cover 2 12 and calf cover 1 11 are covered with a waterproof component;

[0065] The operating module assembly is installed in the lower cover 17 of the fuselage;

[0066] A guide and limiting assembly is installed on the lower cover 17 of the fuselage.

[0067] The hip joint motor 16 and the knee joint motor 13 drive the amphibious quadruped robot 4, and the two sides of the lower cover 17 of the body on the thigh cover 2 14 are installed with the calf cover 11, the calf cover 2 12, the thigh cover 2 14 and the thigh cover 1 15 to move alternately.

[0068] The lower cover 17 of the fuselage is correspondingly covered with the upper front cover 21 and the upper rear cover 22 of the fuselage. The upper rear cover 22 is equipped with a power switch 19, and the upper front cover 21 is equipped with a code burning port 20 and a charging port 201.

[0069] The waterproof component includes a fuselage lower cover interlayer 24, a hip joint fixing interlayer 26, a calf cover interlayer 27, a fuselage upper cover interlayer 28, a thigh cover interlayer 29 and a single chip computer 30;

[0070] A fuselage lower cover interlayer 24 is installed around the inner side of the fuselage lower cover 17, and a fuselage upper cover interlayer 28 is installed around the inner and outer circles of the fuselage front cover 21 and the fuselage rear cover 22. A thigh cover interlayer 29 is installed at the joint between the inner side of the thigh cover 2 14 and the thigh cover 1 15. A hip joint fixing interlayer 1 26 is installed at one end of the fuselage lower cover 17, and a single-chip computer 30 is installed on the right side of the hip joint fixing interlayer 26. A calf cover interlayer 27 is installed at the connection between the inner side of the calf cover 2 12 and the calf cover 1 11. The fuselage lower cover interlayer 24 and the fuselage upper cover interlayer 28 are fitted and connected to each other.

[0071] The operation module assembly separates the communication module 25 , which is installed on one side of the single chip microcomputer 30 in the lower cover 17 of the fuselage.

[0072] The guide and limit assembly includes a quadruped robot fixing frame 1, a guide rail 2, a slide rail support plate 3, a sensor connector 5, a force sensor 6, an upper sensor fixing frame 7, a lower sensor fixing frame 8, a profile 9 and a small slider 10;

[0073] The outer side of the amphibious quadruped robot 4 is clamped and installed with a quadruped robot fixing frame 1, and the upper end of the quadruped robot fixing frame 1 is installed with a slide rail support plate 3. The upper sensor fixing frame 7 and the lower sensor fixing frame 8 are symmetrically installed on both sides of the slide rail support plate 3. A sensor connector 5 and a force sensor 6 are installed between the upper sensor fixing frame 7 and the lower sensor fixing frame 8. The slide rail support plate 3 is sleeved on the profile 9, and the small slider 10 is flipped on the guide rail 2. The guide rail 2 is fixed to the slide rail support plate 3 by screws and nuts. The slide rail support plate 3 is clamped on the profile 9 by screws and nuts. The guide rails 2 are respectively installed on both sides of the slide rail support plate 3. The upper sensor fixing frame 7 and the lower sensor fixing frame 8 are adjusted and connected along the guide rail 2;

[0074] The clamping plate and the slider can follow the robot's forward movement. The rear end of the quadruped robot's fixed frame 1 is first fixed with a sensor fixing piece by screws. The sensor connector 1 and the connector are then fixed in the axial direction by cylindrical pins. A force sensor 6 is clamped between the sensor connector 2 and the sensor fixing frame. The groove of the sensor fixing frame is also stuck on the guide rail 2, and the fixing frames are fastened with screws.

[0075] The sensor connector 1 5, force sensor 6, upper sensor bracket 7, and lower sensor bracket 8 follow the up-and-down movement of the amphibious quadruped robot 4, rather than measuring the forward and backward movement of the drag force. The connection method of the parts is the same for measuring thrust and drag force, with only the mounting method of the profiles and splints changing. The quadruped robot shell is made of 3D-printed PLA material, and the rotation joints of the legs are constructed with waterproof motors.

[0076] The profile 9 is connected vertically by die-cast aluminum angles and then fastened with bolts. The two slide rail support plates are fixed with screws and then wrapped around the aluminum profile. The guide rail 2 is placed on top of the support plate and stuck in the groove of the smooth small slider 10. The two quadruped robot fixing frames 1 are fixed with screws, with the upper support surface placed on the small slider 10, and the large groove at the lower end is used to clamp the body of the amphibious quadruped robot 4;

[0077] When the legs of the amphibious quadruped robot 4 are subjected to thrust or resistance while moving underwater, since the grooves of the small slider 10 and the upper sensor bracket 7 and the lower sensor bracket 8 are smooth enough, the quadruped robot drives the splint, bracket, connector, etc. supported by the aluminum profile to move linearly along the guide rail 2 under the action of water force.

[0078] Thigh cover 1 15 and thigh cover 2 14 are assembled and the knee joint motor 13 is fixed using the reserved holes at both ends.

[0079] The small slider 10 and the quadruped robot fixing frame 1 move up and down following the amphibious quadruped robot 4 , and the fuselage lower cover 17 , the fuselage front cover 21 , and the fuselage upper rear cover 22 are sealed by the waterproof glue coating area 18 and the waterproof glue coating area 23 .

[0080] The amphibious quadruped robot 4 is connected by linear motion along the guide rail 2 under the action of water power.

[0081] The amphibious quadruped robot 4 has a symmetrical calf cover 1 11, calf cover 2 12, knee joint motor 13, thigh cover 2 14, thigh cover 1 15 and hip joint motor 16, which are a structure that moves alternately one side forward and the other side backward.

[0082] like Figure 1 - Figure 10 As shown, the working process of the structural design, paddling gait planning and testing device of a bionic canine amphibious robot provided in this embodiment is as follows:

[0083] Step 1: The profile 9 is connected vertically by die-casting angle aluminum and then fastened with bolts. The two slide rail support plates are fixed with screws and then wrapped with the aluminum profile. The guide rail 2 is placed on top of the support plate and stuck in the groove of the smooth small slider 10. The two quadruped robot fixing frames 1 are fixed with screws, with the upper support surface placed on the small slider 10 and the large groove at the lower end used to clamp the amphibious quadruped robot 4 fuselage.

[0084] Step 2: The clamping plate and the slider can follow the robot's forward movement. The rear end of the quadruped robot's fixed frame 1 is first fixed with a sensor fixing piece by screws. The sensor connector 1 5 and the connecting piece are then fixed in the axial direction by cylindrical pins. A force sensor 6 is clamped between the sensor connector 2 and the sensor fixing frame. The groove of the sensor fixing frame is also stuck on the guide rail 2. The fixing frames are fastened with screws.

[0085] Step 3: The sensor connector 1 5, force sensor 6, upper sensor bracket 7, and lower sensor bracket 8 follow the up and down movement of the amphibious quadruped robot 4, rather than measuring the forward and backward movement of the drag force. The connection method of the parts is the same for measuring thrust and drag force, only the installation method of the profile and splint is changed. The quadruped robot shell is made of PLA material 3D printing, and the rotation joints of the legs are built with waterproof motors.

[0086] Step 4: When the legs of the amphibious quadruped robot 4 are subjected to thrust or resistance while moving underwater, the grooves of the small slider 10 and the lower fixing frame 8 of the sensor are smooth enough. Therefore, under the action of the hydrodynamic force, the quadruped robot drives the plywood, fixing frame, connecting parts, etc. supported by the aluminum profile to move linearly along the guide rail 2. The upper fixing frame 7 of the sensor is completely stuck, while the lower fixing frame 8 of the sensor is movable. The strain sensor measures the force received by the change of strain, so one end is stuck and the other end is movable, that is, one end of the sensor is fixed to the upper fixing frame 7 of the sensor, and the other end connected to the lower fixing frame 8 of the sensor is movable.

[0087] The profile 9, sensor 6, sensor upper fixing frame 7, slide rail 2, and guide rail support plate 3 are all fixed, while the amphibious quadruped robot 4, quadruped robot fixing frame 1, sensor lower fixing frame 8, and connector 5 will move on the slide rail according to the force applied to them;

[0088] Step 5: Since the force sensor 6 is clamped by the sensor connector 1 5, the upper sensor mounting bracket 7, and the lower sensor mounting bracket 8, when the robot moves forward, the force sensor 6 can measure the thrust provided by the mounting bracket. This thrust is the total thrust experienced by the paddling. When the amphibious quadruped robot 4 moves backward, the force sensor 6 can measure the thrust provided by the sensor connector. This thrust is the total resistance experienced by the paddling.

[0089] Step 6: When the amphibious quadruped robot 4 is subjected to force, it drives the quadruped robot fixing frame 1 and the sensor lower fixing frame 8 to move on the small slider 10, thereby changing the strain of the sensor. The thrust is the lift force exerted on the amphibious quadruped robot 4 when paddling. When the force is downward, the force sensor 6 detects the thrust of the sensor upper fixing frame 7 and the sensor lower fixing frame 8, which is the negative lift force exerted on the robot when paddling. By comparing the two force measuring devices, it can be found that only by modifying the installation method of the aluminum profile and the installation method of the splint, the force conditions in multiple directions can be measured.

[0090] Example 1

[0091] Use sandwich structure for waterproofing, see the specific picture Figure 4 There is a layer between the upper and lower covers of the fuselage to enhance the sealing and prevent water penetration;

[0092] An extra space is left above the body for code burning and battery charging. When code burning and battery charging are not needed, it is sealed with silicone and covered with waterproof tape. When code burning and charging are needed, the tape and silicone are peeled off. It is easier to charge than disassembling the body to take out the battery. Specific pictures can be seen Figure 2 ;

[0093] In order to lower the center of gravity of the quadruped robot and increase the center of buoyancy, the amphibious quadruped robot uses direct knee joint drive, and the drive motor is installed at the knee joint to lower the center of gravity of the quadruped robot. To increase buoyancy, the volume of the fuselage can be increased. However, in order to reduce the resistance caused by the fuselage, the volume is increased by the height or length of the fuselage, rather than the width. The length, width, and height ratio of the robot's body is approximately 15:5:3.

[0094] In order to maximize the propulsion of the quadruped robot underwater, we need to expand the width of the robot's legs, that is, widen the width of the quadruped robot's legs. However, too wide a leg width will add extra weight and affect its mobility on land. Therefore, we increase the width of the robot's legs to the same width as the motor, and use a hollow cavity structure to widen the robot's leg structure without adding too much weight, thereby achieving a larger contact area between the legs and the water and increasing the propulsion ability. The specific picture can be seen Figure 1 ;

[0095] Necessary components for the robot's underwater force measurement device:

[0096] The device bracket is constructed from profile 9, quadruped robot fixing frame 1, sensor connector 5, sensor connector 25, sensor fixing frame 7, guide rail 2, small slider 10, slide rail support plate 3, force sensor 6, amphibious quadruped robot 4 and several screws. The devices for measuring drag force, thrust, lift and resistance have the same numbers as shown in the following figure. Figure 5-10 Several die-cast aluminum angles, two quadruped robot fixing frames, two sensor connectors, a sensor fixing frame, a guide rail, a small slider, two slide rail support plates, a one-dimensional force sensor, a quadruped robot, and several screws;

[0097] Connection of force measuring device parts: Profile 9 is connected vertically by die-cast aluminum angles and then fastened by bolts. Two slide rail support plates are fixed by screws and then wrapped around the aluminum profile. The guide rail 2 is placed on top of the support plate and stuck in the groove of the smooth small slider 10.

[0098] After the two quadruped robot clamps 1 are fixed together by screws, the upper support surface is placed on the small slider 10, and the large groove at the lower end is used to clamp the quadruped robot body. The clamp and the slider can follow the robot's forward movement. The rear end of the quadruped robot fixing frame 1 is first fixed with a sensor fixing part 1 by screws, and the sensor connecting part 5 and the connecting part 2 are then screwed to ensure the fixed connection in the axial direction;

[0099] A force sensor is clamped between the sensor connector 2 and the sensor mounting bracket. The groove of the sensor mounting bracket is also stuck on the guide rail 2. The mounting brackets are fastened with screws.

[0100] The devices for measuring drag and lift operate on the same principle; the only difference is that the slider and sensor plate follow the robot's up-and-down motion, rather than measuring the forward and backward movement of drag. The connection method for measuring thrust and drag is the same, with only the mounting method of the profiles and plates changing. The quadruped robot's shell is 3D-printed from PLA material, and the leg's rotary joints are constructed with waterproof motors to ensure stable experimental power.

[0101] Example 2

[0102] like Figure 7 When a quadruped robot or its legs are subjected to thrust or resistance while moving underwater, the grooves of the slider and the sensor holder are smooth enough. Therefore, under the action of water power, the quadruped robot drives the clamping plate, the holder, the connecting parts and the like supported by the aluminum profile to move linearly along the guide rail. Since the force sensor is clamped by the connecting parts and the holder, when the robot moves forward, the force sensor can measure the thrust provided by the holder, which is the total thrust experienced by the stroke. When the robot moves backward, the force sensor can measure the thrust provided by the sensor connector, which is the total resistance experienced by the stroke.

[0103] like Figure 9 When the robot is subjected to an upward force from the water, the force sensor measures the thrust provided by the fixed frame, which is the lift force exerted by the robot while paddling. When the force is directed downward, the force sensor detects the thrust of the fixed frame, which is the negative lift force exerted by the robot while paddling. Comparing the two force measurement devices, it can be found that by simply modifying the installation method of the aluminum profile and the installation method of the splint, it is possible to measure the force conditions in multiple directions.

[0104] The proposal and principle of underwater gait of bionic quadruped amphibious robot:

[0105] In order to help quadruped robots advance in water environments, traditional land motion schemes may not work. We propose two swimming gaits suitable for bionic quadruped amphibious robots to advance underwater, which can help quadruped robots cope with water environments. When quadruped robots need to cross rivers during field operations, they can cross the river by gait conversion. The proposed swimming gaits are Lateral-Sequence Padding Gait (LSPG), which is translated into lateral sequence paddling gait in Chinese, and Trot-Like Padding Gait (TLPG), which is translated into diagonal paddling gait in Chinese. Figure 13 , (a) is the present invention based on Figure 11 ,(a) Phase diagram of the limbs of the optimized quadruped robot when swimming.,In a complete swimming cycle, there are two main phases, namely PowerPhase (power phase) and RecoveryPhase (recovery phase).,The power phase is as follows Figure 11 ,(b) shows that the robot's legs are paddling backwards. At this time, the legs are stretched as much as possible to obtain a larger contact area with the water, thereby generating a greater forward propulsion force. The recovery phase is as follows Figure 11 In (c), the robot's legs are retracted as much as possible to keep them parallel to the body, reducing the force acting on the water and thus reducing the resistance on the legs. Through the periodic and repeated movement of the legs, the propulsion force of the legs is greater than the resistance, thus achieving the forward movement of mammals;

[0106] The power phase of the limbs of real canine mammals accounts for about 24.3% to 33.7%. This data comes from a bionics paper. Figure 1 In (a), LH stands for LeftHind, i.e., the left hind leg, LFLeftFront is the left front leg, RFRightFront is the right front leg, and RHRightHind is the right hind leg. Therefore, the figure shows the proportion of the four-legged power phase of real canine mammals in the entire cycle. Figure 11 ,(a) Phase diagram of the limbs of a real canine mammal swimming,(b) Schematic diagram of the robot leg paddling in the PowerPhase stage,(c) Schematic diagram of the robot leg paddling in the RecoveryPhase stage;

[0107] like Figure 12 As shown, state 1 indicates that the robot's right front leg is at the end of the power phase and is about to enter the recovery phase. State 2 indicates that the robot's right front leg is at the end of the recovery phase and is about to enter the power phase. The following is a detailed description of Lateral-SequencePaddingGait. The phase diagram is as follows Figure 13 , (a) shows that compared with Figure 11 (a) Phase diagram of a real canine mammal. The power phases of the four limbs are different. We made some simplifications and evenly distributed the power phases of the robot's four legs with the same proportion, each accounting for 25%. LSPG imitates the swimming action of canine mammals in nature. The four legs take turns to do the paddling action to achieve the four-legged paddling sequence of LH-RF-RH-LF. This gait has a fast instantaneous paddling speed of the robot's legs and a large reaction force, so the robot can obtain a larger acceleration and speed limit.

[0108] Next, we introduce Trot-LikePaddingGait, which is a diagonal paddling gait. TLPG imitates the swimming action of minks in nature and realizes the robot's forward movement by paddling diagonally. The gait phase diagram is shown as follows: Figure 13 As shown in (b), compared with the alternating stroke action, this gait uses the diagonal legs to perform the stroke motion. At the same time, two legs are in the power phase. For example, at 0% to 50% of the cycle, LH and RF are in the power phase, and at 50% and 100% of the cycle, LF and RH are in the power phase. Compared with the above-mentioned canine-like swimming gait, the power phase of this gait accounts for a larger proportion, and the relative stroke speed is slower, that is, within the same cycle, the backward stroke speed is slower, so the propulsion force obtained is smaller;

[0109] Figure 13, (a) The proposed Lateral-SequencePaddingGait is derived from the paddling action of canine mammals. (b) The proposed Trot-LikePaddingGait gait limb phase diagram is derived from the paddling action of mink mammals. Summary: When the water surface is relatively calm, LSPG is used. This gait imitates canine mammals in nature and propels the robot in the water environment by paddling with four legs in turn. This solution has a higher speed but poor stability. In the case of wanting to obtain larger acceleration and speed, another gait TLPG is characterized by slow speed but strong stability. It is suitable for scenarios where you want to obtain higher stability but not high speed requirements.

[0110] Example 3

[0111] Based on the above bionic principles, we proposed two gaits to help the robot move forward in a water environment. For the robot's paddling action, we refer to the real paddling action of canine mammals, such as Figure 14 As shown in the figure, by imitating the real canine mammals’ paddling motion, we developed a paddling motion suitable for robots. We determined the range of motion and motion cycle of the thighs and calves, and decomposed a paddling motion into 12 key position points, namely Figure 11 , (b) (c) show the 12 key positions of the water-stroke motion we proposed;

[0112] Figure 14 , a schematic diagram of the paddling limbs of canine mammals, which comes from the paper "The "dog paddle": Stereotypic swimming gait pattern in different dog breeds";

[0113] After obtaining these 12 key positions, we can actually get the angle relationship between the thigh and the calf. By solving the inverse kinematics of the leg, we can get the joint angles of the 12 key positions. We use the Fourier function to fit the joint angles of the 12 key positions, such as Figure 5 As shown in the figure, θ1 is the angle between the thigh along the negative direction of the x-axis, and θ2 is the angle between the calf and the thigh. Examples of θ1 and θ2 can be seen. Figure 11 (b) (c) The Fourier function expression used is, where the various parameters can be seen in Table S1.Fourier parameter table. With the expression of the leg angle over time, we only need to make the motor angle move according to this function expression to realize the robot's paddling gait;

[0114]

[0115] Table S1.Fourier parameter table

[0116]

[0117] Figure 15 - Fourier function is used to fit 12 key positions. (a) The fitting situation with PowerPhase accounting for 50%. The solid line is the fitting curve of the thigh angle changing with time, and the dotted line is the fitting curve of the calf joint angle changing with time. The solid triangles are the angles of the key thigh positions, and the hollow triangles are the angles of the key calf positions. (b) The fitting situation with PowerPhase accounting for 25%.

[0118] The beneficial effects of this embodiment are:

[0119] 1- The quadruped robot can achieve movement in amphibious environments without the need for additional propulsion devices or deformation devices;

[0120] 2. The underwater gait is scientific and reasonable, based on bionic principles and existing bionics literature. Experimental testing has shown that the underwater movement speed can reach 0.6BL / s (0.6 body lengths / second), laying an important foundation for the amphibious development of quadruped robots.

[0121] 3. The basic structural changes to the current quadruped robot are minimal, except for adding waterproofing and slightly increasing the width of the quadruped's legs, which can enable movement in amphibious environments.

[0122] 4. The underwater force measurement method proposed in this invention addresses the difficulty in directly measuring the dynamic forces exerted on amphibious robots while moving in water. By using an equivalent replacement method, the thrust exerted by a fixed frame or connector on the force sensor is equated to the thrust and resistance exerted on the quadruped robot while moving in water. This method is clear and efficient, with reliable connections between components, adaptable to various underwater environments, and capable of measuring the forces exerted on the robot without disassembling the device.

[0123] 5. By slightly changing the connection method between the aluminum profiles, the hydrodynamic conditions acting on the robot in a direction orthogonal to the current force measurement direction can be obtained. Moreover, the measured force is not limited to a single vector direction; the device can obtain the force conditions in two opposite vector directions. Compared with existing technologies, this force measurement method is more efficient and accurate. It can change the force measurement direction according to actual needs, realize autonomous measurement, and does not require manual operation. It has a wide range of applications and can be used to measure the force of a single leg or the entire amphibious robot.

[0124] The above is only a further embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes based on the technical solutions and concepts of the present invention within the scope disclosed by the present invention, which fall within the scope of protection of the present invention.

Claims

1. A bionic canine amphibious robot structural design and paddling gait planning and testing device, characterized by: The invention comprises a body lower cover (17) for limiting, the body lower cover (17) being installed on the amphibious quadruped robot (4), and the two sides of the body lower cover (17) on the thigh cover 2 (14) are correspondingly and alternately installed with the calf cover 1 (11), the calf cover 2 (12), the knee joint motor (13), the thigh cover 2 (14), the thigh cover 1 (15) and the hip joint motor (16); Hip joint motors (16) are symmetrically mounted on both sides of the lower cover (17) of the body, thigh cover 1 (15) is mounted on the output end of the hip joint motor (16), thigh cover 1 (15) is covered on the outer side of thigh cover 1 (15), and knee joint motors (13) are mounted on the inner side of thigh cover 2 (14) and the end of thigh cover 1 (15); The output end of the knee joint motor (13) is installed with a calf cover 2 (12), and the outer side of the calf cover 2 (12) is covered with a calf cover 1 (11); A waterproof component is covered between the lower cover (17) of the body, the thigh cover 1 (15), the thigh cover 2 (14), the knee joint motor (13), the calf cover 2 (12) and the calf cover 1 (11); An operating module assembly is installed in the lower cover (17) of the fuselage; A guide limit assembly is installed on the lower cover (17) of the fuselage; The lower cover (17) of the fuselage is covered with the upper front cover (21) and the rear cover (22) of the fuselage, the rear cover (22) of the fuselage is provided with a power switch (19), and the upper front cover (21) of the fuselage is provided with a code burning port (20) and a charging port (201); The waterproof component includes a fuselage lower cover interlayer (24), a hip joint fixing interlayer (26), a calf cover interlayer (27), a fuselage upper cover interlayer (28), a thigh cover interlayer (29) and a single chip computer (30); The fuselage lower cover interlayer (24) is mounted around the inner side of the fuselage lower cover (17), the fuselage upper front cover (21) and the fuselage upper rear cover (22) are mounted around the inner and outer circles of the fuselage upper cover interlayer (28), the thigh cover interlayer (29) is mounted at the joint between the inner side of the thigh cover 2 (14) and the thigh cover 1 (15), the hip joint fixing interlayer 1 (26) is mounted at one end of the fuselage lower cover (17), the single chip computer (30) is mounted on the right side of the hip joint fixing interlayer 1 (26), the calf cover interlayer (27) is mounted at the joint between the inner side of the calf cover 2 (12) and the calf cover 1 (11), and the fuselage lower cover interlayer (24) and the fuselage upper cover interlayer (28) are bonded to each other; The guide and limit assembly includes a quadruped robot fixing frame (1), a guide rail (2), a slide rail support plate (3), a sensor connecting piece (5), a force sensor (6), an upper sensor fixing frame (7), a lower sensor fixing frame (8), a profile (9) and a small slider (10); The outer side of the amphibious quadruped robot (4) is clamped and installed with a quadruped robot fixing frame (1), the upper end of the quadruped robot fixing frame (1) is installed with a slide rail support plate (3), the two sides of the slide rail support plate (3) are symmetrically installed with a sensor upper fixing frame (7) and a sensor lower fixing frame (8), a sensor connector (5) and a force sensor (6) are installed between the sensor upper fixing frame (7) and the sensor lower fixing frame (8), the slide rail support plate (3) is sleeved on the profile (9), the small slider (10) is flipped on the guide rail (2), the guide rail (2) is fixed on the slide rail support plate (3) by screws and nuts, the slide rail support plate (3) is clamped on the profile (9) by screws and nuts, the guide rails (2) are installed on both sides of the slide rail support plate (3), the sensor upper fixing frame (7) and the sensor lower fixing frame (8) are adjusted and connected along the guide rail (2).

2. The structural design, paddling gait planning, and testing device for a bionic canine amphibious robot according to claim 1 is characterized by: The operating module assembly separates the communication module (25), and the communication module (25) is installed on one side of the single chip microcomputer (30) in the lower cover (17) of the fuselage.

3. The structural design and paddling gait planning and testing device for a bionic canine amphibious robot according to claim 2, characterized in that: Thigh cover 1 (15) and thigh cover 2 (14) are assembled and the knee joint motor (13) is fixed using the reserved holes at both ends.

4. The structural design and paddling gait planning and testing device for a bionic canine amphibious robot according to claim 3, characterized in that: The small slider (10) and the quadruped robot fixing frame (1) move up and down following the amphibious quadruped robot (4), and the lower cover (17) of the fuselage, the front cover (21) of the fuselage, and the rear cover (22) of the fuselage are sealed by the first waterproof glue coating point (18) and the second waterproof glue coating point (23).

5. The structural design and paddling gait planning and testing device for a bionic canine amphibious robot according to claim 4, characterized in that: The amphibious quadruped robot (4) is connected to the guide rail (2) in a linear motion under the action of water power.

6. The structural design and paddling gait planning and testing device for a bionic canine amphibious robot according to claim 5, characterized in that: The amphibious quadruped robot (4) has a symmetrical lower leg cover 1 (11), lower leg cover 2 (12), knee joint motor (13), thigh cover 2 (14), thigh cover 1 (15) and hip joint motor (16) on both sides, which form a structure that moves alternately from one side forward to the other side backward.

7. A method for testing the structural design and paddling gait planning of a bionic canine amphibious robot, based on the device for testing the structural design and paddling gait planning of a bionic canine amphibious robot according to any one of claims 1 to 6, characterized in that: The following steps are also included: Step 1: The profile (9) is vertically connected by die-cast angle aluminum and then fastened by bolts. The two slide rail support plates are fixed by screws and then wrapped with the aluminum profile. The guide rail (2) is placed on the top of the support plate and is clamped in the groove of the small slider (10) with a smooth surface; the two quadruped robot fixing frames (1) are fixed by screws, and the upper support surface is placed on the small slider (10). The large groove at the lower end is used to clamp the body of the amphibious quadruped robot (4); Step 2: The clamping plate and the slider can follow the robot's forward movement. The rear end of the quadruped robot fixed frame (1) is first fixed with a sensor fixing piece by screws. The sensor connecting piece (5) and the connecting piece are then fixed in the axial direction by cylindrical pins. A force sensor (6) is clamped between the sensor connecting piece (5) and the sensor fixed frame. The groove of the sensor fixed frame is also stuck on the guide rail (2). The fixing frames are fastened with screws. Step 3: The sensor connector 1 (5), force sensor (6), upper sensor bracket (7) and lower sensor bracket (8) follow the up and down movement of the amphibious quadruped robot (4), rather than the forward and backward movement to measure the drag force. The connection method of the parts is the same in measuring thrust and drag force, only the installation method of the profile and the splint is changed. The shell of the quadruped robot is made of PLA material 3D printing, and the rotation joint of the leg is built by a waterproof motor; Step 4: When the legs of the amphibious quadruped robot (4) are subjected to thrust or resistance while moving underwater, the grooves of the small slider (10) and the lower fixing frame (8) of the sensor are smooth enough, so the quadruped robot drives the splint, fixing frame, and connecting parts supported by the aluminum profile to move linearly along the guide rail (2) under the action of water power. The upper fixing frame (7) of the sensor is completely stuck, and the lower fixing frame (8) of the sensor is movable. The strain sensor measures the force received by the change of strain, so one end is stuck and the other end is movable, that is, one end of the sensor is fixed to the upper fixing frame (7) of the sensor and the other end is connected to the lower fixing frame (8) of the sensor and is movable; The profile (9), the sensor (6), the upper sensor fixing frame (7), the guide rail (2), and the guide rail support plate (3) are all fixed, and the amphibious quadruped robot (4), the quadruped robot fixing frame (1), the lower sensor fixing frame (8), and the sensor connecting member (5) will move on the slide rail according to the force applied to them; Step 5: Since the force sensor (6) is clamped by the sensor connector (5), the upper sensor fixing frame (7) and the lower sensor fixing frame (8), when the robot moves forward, the force sensor (6) can measure the thrust provided by the fixing frame, and the thrust is the total thrust of the paddling. When the amphibious quadruped robot (4) moves backward, the force sensor (6) can measure the thrust provided by the sensor connector, and the thrust is the total resistance of the paddling. Step 6: When the amphibious quadruped robot (4) is subjected to force, it drives the quadruped robot fixing frame (1) and the sensor lower fixing frame (8) to move on the small slider (10) to change the strain of the sensor.

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