Amphibious crawling bionic robot leg structure and lightweight design method thereof

Abstract

The invention belongs to the related technical field of biomimetic robots, and discloses a leg structure of an amphibious crawling biomimetic robot and a lightweight design method of the amphibious crawling biomimetic robot. The first end of the thigh inner side plate and the first end of the thigh outer side plate are connected to the driving assembly and can be driven by the driving assembly to rotate integrally; the shank assembly comprises a shank bone, and the top of the shank bone is rotationally connected between the second ends of the thigh assembly; the transmission assembly is arranged between the thigh inner side plate and the thigh outer side plate, and the transmission assembly can be driven by the driving assembly to drive the shank to rotate; the sole assembly is connected to the bottom of the shank bone, and the thigh inner side plate, the thigh outer side plate and the shank bone are of a dot matrix structure. The thigh assembly comprises the independent thigh inner side plate and the independent thigh outer side plate, the thigh inner side plate, the thigh outer side plate and the shank are of a lattice structure, light weight can be better achieved, and the structural performance of the leg is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field related to bionic robots, and more specifically, relates to a leg structure of an amphibious crawling bionic robot and a lightweight design method thereof. Background Art

[0002] In recent years, robotics technology has developed rapidly. While robots are moving into more fields, they are also getting closer to people's lives, which makes people put forward more requirements for them. In addition to completing basic tasks, robots must also meet a series of higher performance requirements such as simple operation, low energy consumption, high flexibility, strong stability and good openness. In particular, bionic robots have more advantages in mobility and environmental adaptability than traditional mobile robots, and are widely used in disaster relief, resource exploration and reconnaissance. In response to the problems of excessive energy consumption, insufficient mobility and flexibility in the field of robots, lightweight design provides a better solution.

[0003] In recent decades, people have gradually increased their research on lightweight robots, and many results have emerged. However, the research on lightweight robots is far from meeting people's requirements and is not enough to support people's demand for its performance. The lightweight of robots is mainly achieved from the aspects of materials and structures. At present, it is very convenient to lightweight robots from the material aspect, but lightweight materials are expensive, difficult to develop, and difficult to apply on a large scale. With the popularization of 3D printing technology, there are fewer and fewer restrictions on lightweighting robots from a structural perspective, and many manufacturing problems have been overcome, and even higher lightweight goals can be achieved with lightweight materials. Therefore, it is of certain significance to design the lightweight structure of the robot leg structure to reduce its own weight while ensuring that it can work normally as required. Summary of the invention

[0004] In response to the above defects or improvement needs of the prior art, the present invention provides an amphibious crawling bionic robot leg structure and a lightweight design method thereof, which are used to solve the problem that the lightweight research of existing robots is far from meeting people's requirements and is insufficient to support people's performance requirements.

[0005] To achieve the above-mentioned purpose, according to a first aspect of the present invention, there is provided an amphibious crawling bionic robot leg structure, comprising a driving component, a thigh component, a transmission component, a calf component and a sole component; the thigh component comprises an inner thigh plate and an outer thigh plate arranged opposite to each other, the first end of the inner thigh plate and the first end of the outer thigh plate are respectively connected to the driving component and can rotate as a whole under the drive of the driving component; the calf component comprises a calf bone, the top of the calf bone is rotationally connected between the second ends of the inner thigh plate and the outer thigh plate; the transmission component is arranged between the inner thigh plate and the outer thigh plate, and the transmission component is transmission-connected between the driving component and the calf bone, and can drive the calf bone to rotate under the drive of the driving component; the sole component is connected to the bottom of the calf bone, and the inner thigh plate, the outer thigh plate and the calf bone are set as a lattice structure.

[0006] According to the leg structure of an amphibious crawling bionic robot provided by the present invention, the driving assembly includes a first joint motor, a second joint motor and a third joint motor; the first joint motor is used to be connected to the robot body, the output end of the first joint motor is connected to the second joint motor through a first motor connector, the output end of the second joint motor is connected to the third joint motor through a second motor connector, the output end of the third joint motor is connected to the transmission assembly, the second joint motor and the third joint motor are coaxial, the second joint motor is used to drive the thigh assembly to perform leg lifting and leg retracting movements, and the third joint motor is used to drive the calf assembly to perform leg lifting and leg retracting movements.

[0007] According to the leg structure of an amphibious crawling bionic robot provided by the present invention, the transmission assembly is a synchronous belt assembly, and the synchronous belt assembly includes a driving wheel, a driven wheel and a transmission belt. The driving wheel is rotatably connected to the first end of the thigh assembly and is connected to the driving assembly, the driven wheel is rotatably connected to the second end of the thigh assembly and is integrally rotatably connected to the calf bone, and the transmission belt is tensioned on the outside of the driving wheel and the driven wheel.

[0008] According to the leg structure of the amphibious crawling bionic robot provided by the present invention, the synchronous belt assembly also includes a belt tensioner, and bosses are respectively provided on the opposite sides of the inner thigh plate and the outer thigh plate, and the belt tensioner is arranged on the bosses to tighten the transmission belt.

[0009] According to the leg structure of the amphibious crawling bionic robot provided by the present invention, the inner thigh plate is connected to the driving assembly on one side of the driving wheel, the first end of the outer thigh plate is connected to an arc-shaped connecting plate, and the outer thigh plate is connected to the driving assembly on the other side of the driving wheel through the arc-shaped connecting plate;

[0010] The calf bone comprises two calf plates arranged opposite to each other and a reinforcing plate connected between the two calf plates.

[0011] According to the leg structure of an amphibious crawling bionic robot provided by the present invention, the sole component includes a ball-foot base and a ball-foot foot cover, the top of the ball-foot base is connected to the bottom of the calf bone, the bottom of the ball-foot base is spherical, and the ball-foot foot cover is sleeved on the outside of the ball-foot base.

[0012] According to a second aspect of the present invention, a lightweight design method for the leg structure of an amphibious crawling bionic robot is provided. Based on the leg structure of an amphibious crawling bionic robot described in any one of the above, the lightweight design method comprises:

[0013] Design the shape and size of the leg structure and obtain an initial leg structure model;

[0014] Designing a reduction hole for the initial leg structure model to obtain a reduced leg structure model;

[0015] Under preset force conditions and preset constraint conditions, the reduced-weight leg structure model is subjected to a lattice filling design on the structures of the inner thigh plate, the outer thigh plate and the calf bone with maximizing stiffness as an optimization goal, so as to obtain a lightweight leg structure model;

[0016] The lightweight leg structure model is strength-checked, and the lightweight design is completed after the check.

[0017] According to the lightweight design method for the leg structure of an amphibious crawling bionic robot provided by the present invention, the preset force working condition is determined by the following method:

[0018] The motion trajectory of the amphibious crawling bionic robot is planned in the diagonal gait and the tripod gait respectively, and the simulated motion is performed according to the corresponding gait according to the planned motion trajectory;

[0019] Obtain the force conditions on the sole of the leg structure of the amphibian crawling bionic robot during the simulation movement;

[0020] The maximum force condition of the sole during the simulated movement is selected as the preset force condition; wherein the maximum force condition includes the force magnitude and force direction of the sole of the leg structure and the corresponding standing posture of the leg structure.

[0021] According to the lightweight design method of the leg structure of an amphibious crawling bionic robot provided by the present invention, the preset force condition is specifically: the standing height of the leg structure is 0.16-0.20m, the force components of the foot end of the leg structure in two horizontal directions are 45-60N and 18-30N, and the force component in the vertical direction is 660-700N;

[0022] The preset constraint condition is specifically: setting the driving component as a fixed constraint surface.

[0023] According to the lightweight design method for the leg structure of an amphibious crawling bionic robot provided by the present invention, strength verification of the lightweight leg structure model is performed, specifically comprising:

[0024] Finite element analysis is performed on the lightweight leg structure model under preset stress conditions and preset constraint conditions to obtain strain information on the surface of the leg structure, and it is determined whether the strength requirements are met based on the strain information.

[0025] In general, compared with the prior art, the above technical solutions conceived by the present invention provide an amphibious crawling bionic robot leg structure and a lightweight design method thereof:

[0026] 1. The thigh assembly includes an independent inner thigh plate and an outer thigh plate, which reduces the number of components, reduces complexity, is conducive to reducing the weight of the thigh, and is convenient for assembling and setting the intermediate transmission assembly; the drive assembly is centrally arranged at the first end of the thigh assembly, so that there is no need to arrange the drive assembly at the calf, which is conducive to improving the flexibility of leg movement and improving leg performance; the inner thigh plate, the outer thigh plate and the calf bone are arranged as a lattice structure, which further reduces the weight of the leg, is conducive to better achieving lightweight and improving the performance of the leg structure;

[0027] 2. The calf is driven by a synchronous belt. Compared with the existing quadruped robot that uses a connecting rod to drive the calf, the calf has a larger range of motion and the transmission is more direct and efficient; the thigh assembly is divided into two parts, and the synchronous belt and its tensioning device are hidden in the middle, which is easy to assemble and has a more compact structure;

[0028] 3. Considering the actual working conditions and design requirements, the initial leg structure model of the amphibious crawling bionic robot is established. At the same time, the weight-reduction empirical design combined with the grid optimization technology is used to design the main parts of the leg structure of the amphibious crawling bionic robot in a lightweight way, while ensuring the rigidity of the leg structure, reducing its weight, and indirectly improving its flexibility and movement ability;

[0029] 4. When optimizing the grille, it is proposed to perform motion planning and simulation based on different gait modes respectively, and select the maximum force condition as the preset force condition based on the force in the simulated motion process, so that the optimization process of the lattice structure grille is more reliable, and the final leg structure obtained after the optimized design can better meet the needs of normal activities. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is an overall schematic diagram of the leg structure of the amphibious crawling bionic robot provided by the present invention;

[0031] Figure 2 is a schematic diagram of the inner thigh board provided by the present invention;

[0032] Figure 3 is a schematic diagram of the outer thigh board provided by the present invention;

[0033] Figure 4 is a schematic diagram of a tibia provided by the present invention;

[0034] Throughout the drawings, the same reference numerals are used to denote the same elements or structures, wherein:

[0035] 1. First joint motor; 2. Second joint motor; 3. Third joint motor; 4. First motor connector; 5. Second motor connector; 6. Inner thigh plate; 7. Outer thigh plate; 8. Synchronous belt assembly; 9. Belt tensioner; 10. Calf bone; 11. Ball foot base; 12. Ball foot foot cover. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0037] See also Figure 1 The present embodiment provides a leg structure of an amphibious crawling bionic robot, which includes a driving component, a thigh component, a transmission component, a calf component and a sole component; the thigh component includes an inner thigh plate 6 and an outer thigh plate 7 arranged opposite to each other, the first end of the inner thigh plate 6 and the first end of the outer thigh plate 7 are respectively connected to the driving component and can rotate as a whole under the drive of the driving component; the calf component includes a calf bone 10, the top of the calf bone 10 is rotationally connected between the inner thigh plate 6 and the second end of the outer thigh plate 7; the transmission component is arranged between the inner thigh plate 6 and the outer thigh plate 7, and the transmission component is transmission-connected between the driving component and the calf bone 10, and can drive the calf bone 10 to rotate under the drive of the driving component; the sole component is connected to the bottom of the calf bone 10, and the inner thigh plate 6, the outer thigh plate 7 and the calf bone 10 are set as a lattice structure.

[0038] refer to Figure 1In some specific embodiments, the driving assembly includes a first joint motor 1, a second joint motor 2 and a third joint motor 3; the first joint motor 1 is used to be connected to the robot body, the output end of the first joint motor 1 is connected to the second joint motor 2 through the first motor connector 4, the output end of the second joint motor 2 is connected to the third joint motor 3 through the second motor connector 5, the output end of the third joint motor 3 is connected to the transmission assembly, the second joint motor 2 and the third joint motor 3 are coaxial, the second joint motor 2 is used to drive the thigh assembly to lift and retract the leg, and the third joint motor 3 is used to drive the calf assembly to lift and retract the leg.

[0039] The first joint motor 1 is used to drive the second joint motor 2, the third joint motor 3, the thigh assembly, the calf assembly and the sole assembly to rotate as a whole, that is, to connect with the fuselage to provide a rotational movement similar to the hip joint. The second joint motor 2 is used to drive the third joint motor 3, the thigh assembly, the calf assembly and the sole assembly to rotate, which can realize the thigh leg lifting and leg retracting movements. The movement axis of the second joint motor 2 is perpendicular to the movement axis of the first joint motor 1. The third joint motor 3 is used to drive the calf assembly and the sole assembly to rotate through the transmission assembly, which can realize the calf assembly Leg lifting and leg retracting movements. The sole assembly is used to contact the ground.

[0040] refer to Figure 1 In some specific embodiments, the transmission assembly is a synchronous belt assembly 8, which includes a driving wheel, a driven wheel and a transmission belt. The driving wheel is rotatably connected to the first end of the thigh assembly and connected to the driving assembly, and the driven wheel is rotatably connected to the second end of the thigh assembly and is integrally rotatably connected to the calf bone 10. The transmission belt is tensioned on the outside of the driving wheel and the driven wheel. The driving assembly is used to drive the driving wheel to rotate, and the driving wheel drives the driven wheel to rotate through the transmission belt, and the driven wheel drives the calf bone 10 to rotate integrally.

[0041] Furthermore, the synchronous belt assembly 8 further includes a belt tensioner 9, and bosses are respectively provided on the opposite sides of the inner thigh plate 6 and the outer thigh plate 7, and the belt tensioner 9 is arranged on the bosses for tensioning the transmission belt. The belt tensioner 9 is arranged for tensioning the transmission belt, which is beneficial to ensuring the transmission efficiency.

[0042] Specifically, near the middle position of the thigh assembly (near the middle position of the two pulleys), there is a synchronous belt tensioning device on the upper and lower sides of the synchronous belt. The tensioning method is to tighten the M3 tensioning bolt to press the synchronous belt downward / upward (squeeze the synchronous belt toward the middle) to achieve tensioning.

[0043] Specifically, refer to Figure 1 and Figure 2The inner thigh plate 6 is connected to the driving assembly on one side of the driving wheel, referring to Figure 1 and Figure 3 The first end of the outer thigh plate 7 is connected to an arc-shaped connecting plate, and the outer thigh plate 7 is connected to the driving component on the other side of the driving wheel through the arc-shaped connecting plate.

[0044] The first ends of the inner thigh plate 6 and the outer thigh plate 7 are connected to the third joint motor 3 on both sides of the driving wheel, which can provide a connection space between the driving wheel and the output end of the third joint motor 3. The inner thigh plate 6 and the outer thigh plate 7 can be connected to the third joint motor 3 through M3 bolts, and the synchronous belt driving wheel can be fixed to the output flange of the third joint motor 3 through M3 bolts, so that the driving wheel can be smoothly driven to rotate. An opening can be set at the corresponding position of the outer thigh plate 7 and the driving wheel, and a wheel cover can be detachably connected at the opening. The driving wheel can be rotatably connected to the outer thigh plate 7 at the opening on the side close to the outer thigh plate 7. The setting of the arc-shaped connecting plate at the first end of the outer thigh plate 7 can realize the connection between the outer thigh plate 7 and the third joint motor 3, and can play a protective role on the outside of the synchronous belt assembly 8.

[0045] refer to Figure 4 The calf bone 10 includes two calf plates arranged opposite to each other and a reinforcing plate connected between the two calf plates.

[0046] The driven wheel can be rotatably connected to the thigh assembly through a rotating shaft. Specifically, the driven wheel is integrally rotatably connected to the rotating shaft, and the integral rotatable connection can be achieved through a key structure or a fixed connection. The rotating shaft is connected to the thigh assembly through a bearing to achieve relative rotation. At this time, the top of the two calf plates of the calf bone 10 can be integrally rotatably connected to the rotating shaft or the driven wheel to achieve rotation relative to the thigh assembly. For example, the top of the calf plate can be set to a y-shape, and the top of the calf plate can be connected to the driven wheel through a bolt to achieve integral rotation with the synchronous belt assembly 8; the top of the calf plate can also be sleeved on the outside of the rotating shaft and be integrally rotatably connected to the rotating shaft through an interference connection or a key connection.

[0047] In other specific embodiments, the driven wheel can also be rotatably connected to the shaft, and the shaft can be fixedly connected to the thigh assembly, so that the driven wheel can also rotate relative to the thigh assembly; in this case, the top of the calf bone 10 can be connected to the driven wheel to achieve integral rotation. The connection method of the driven wheel and the calf bone 10 relative to the thigh assembly is not limited, and the purpose is to enable relative rotation and drive the calf bone 10 to rotate through the rotation of the driven wheel.

[0048] The sole assembly includes a ball foot base 11 and a ball foot cover 12 . The top of the ball foot base 11 is connected to the bottom of the calf bone 10 . The bottom of the ball foot base 11 is spherical. The ball foot cover 12 is sleeved on the outside of the ball foot base 11 .

[0049] At least one of the inner thigh plate 6, the outer thigh plate 7, the calf plate and the reinforcing plate is provided with a weight-reducing hole, i.e., a hollow hole, to reduce weight.

[0050] Furthermore, this embodiment provides an amphibious crawling bionic robot, which includes any of the above-mentioned leg structures of the amphibious crawling bionic robot. Specifically, the bionic robot includes a plurality of the above-mentioned leg structures, and the bionic robot may be a bionic crocodile robot.

[0051] In some specific embodiments, a bionic crocodile robot is provided, the bionic crocodile robot comprising a plurality of leg structures, each leg structure comprising a first joint motor 1, a second joint motor 2, a third joint motor 3, a 1-2 motor connector, i.e. a first motor connector 4, a 2-3 motor connector, i.e. a second motor connector 5, an inner thigh plate 6, an outer thigh plate 7, a synchronous belt assembly 8, a belt tensioner 9, a calf bone 10, a ball foot base 11, and a ball foot cover 12;

[0052] The robot calf is driven by belt drive, the pulley model is S3M trapezoidal gear 48 teeth, and the belt width is 15mm. The inner thigh plate 6 and the outer thigh plate 7 are fixed to the motor by bolts, and the synchronous belt is located in the middle of the above two parts. There are bosses for installing the belt tensioner 9 on the inner thigh plate 6 and the outer thigh plate 7 near the synchronous belt, that is, the inner wall is not a flat surface. Aluminum columns can also be connected between the inner thigh and the outer thigh for reinforcement.

[0053] Furthermore, this embodiment provides a lightweight design method for the leg structure of an amphibious crawling bionic robot. The lightweight design method is based on the leg structure of an amphibious crawling bionic robot described in any one of the above items, and the lightweight design method includes:

[0054] Design the shape and size of the leg structure and obtain an initial leg structure model;

[0055] Designing a reduction hole for the initial leg structure model to obtain a reduced leg structure model;

[0056] Under preset force conditions and preset constraints, the reduced-weight leg structure model is subjected to a lattice filling design on the structures of the inner thigh plate 6, the outer thigh plate 7 and the calf bone 10 with the maximization of stiffness as the optimization goal, to obtain a lightweight leg structure model, and a finite element analysis is performed simultaneously;

[0057] The lightweight leg structure model is strength-checked, and the lightweight design is completed after the check.

[0058] In this embodiment, based on the existing robot leg structure, combined with the actual working conditions and overall structure of the robot, the contour shape and structural size parameters of each leg component can be determined as the initial model of the leg structure; then, based on the load conditions and design experience in the actual application process, while taking into account the manufacturing process technology, holes are opened and deletions are designed in local positions of the leg structure to reduce weight while maintaining structural strength, and finally a reduced leg structure model is obtained after preliminary reduction.

[0059] Then import the reduced leg structure model after preliminary reduction into the Inspire software, check whether the parts are connected correctly, set the design space, set the force conditions according to the extreme conditions in the obtained working condition data, that is, preset force conditions and constraints; then run the optimization, enter the model name in the pop-up dialog box, select the type as grid optimization, the optimization target is to maximize stiffness, set the grid structure related parameters (the unit cell related parameters of the lattice structure can be selected according to recommendations or experience, such as the maximum and minimum rod diameters, target length, etc.), set the filling ratio according to requirements (generally recommended to set it to 100% grid structure) and quality target, and the optimization is completed to obtain the optimized robot leg structure;

[0060] Then, according to the design requirements, it is necessary to check the strength and displacement of the final robot leg structure obtained after optimization to ensure that the deformation of the leg structure is within a safe range under the maximum load, that is, the preset stress condition, and that no fracture occurs. It is also necessary to determine whether the requirements are met in order to make the next adjustment.

[0061] Furthermore, the preset stress condition is determined by the following method:

[0062] The motion trajectory of the amphibious crawling bionic robot is planned in the diagonal gait and the tripod gait respectively, and the simulated motion is performed according to the corresponding gait according to the planned motion trajectory;

[0063] Obtain the force conditions on the sole of the leg structure of the amphibian crawling bionic robot during the simulation movement;

[0064] The maximum force condition of the sole during the simulated movement is selected as the preset force condition; wherein the maximum force condition includes the force magnitude and force direction of the sole of the leg structure and the corresponding standing posture of the leg structure.

[0065] This embodiment proposes to first perform simulation movements in different gait modes, and select the working state at the maximum force as the preset force condition in the lightweight optimization design process according to the actual force condition of the leg structure obtained in the simulation movement, so that the final leg structure obtained after the design can meet the stiffness requirements under the maximum force condition, and then the stiffness can meet the needs of normal activities. Further in-depth consideration of the gait mode of the amphibious crawling bionic robot, two gait modes are proposed: diagonal gait and tripod gait.

[0066] Specifically, according to the different foot contact states corresponding to different gaits of the robot when walking, the robot is modeled as a single rigid body model controlled by the foot contact force. The gait sequence is optimized using continuous decision variables based on the ifopt nonlinear optimization software, the robot motion plan is generated, and the working condition data is further obtained.

[0067] That is, the motion trajectory planning specifically includes: constructing a single rigid body model according to the configuration and mass of the amphibious crawling bionic robot; setting the starting point, end point, gait mode and other parameters of the robot's motion; using the set parameters to construct the initial motion trajectory of the robot's body and foot; adding kinematic and dynamic constraints to the motion trajectory of the body and foot to construct a nonlinear optimization problem; using ifopt nonlinear optimization software to solve and obtain the optimized motion trajectory of the body and foot. By optimizing and solving the motion trajectory, it is possible to obtain a trajectory that meets the kinematic and dynamic constraints and is closer to the real motion, making the acquisition of working condition data more reliable.

[0068] Specifically, the working condition data of the robot legs in diagonal gait and tripod gait are obtained:

[0069] Use a single rigid body model to model the robot, set the number of legs and feet, and the offset of the legs and feet relative to the center of mass of the body; set the inertia matrix of the body and the motion space of the feet, as well as the gait parameters; set the coordinates of the robot's starting and ending points, as well as the robot's posture at the starting and ending points;

[0070] According to the gait parameters, the leg and foot movements are decomposed into a motion sequence consisting of a support phase and a swing phase, the center of mass of the fuselage and the motion trajectory of the foot are initialized, and kinematic and dynamic constraints are added; the duration of the support phase and the swing phase of the foot is optimized using ifopt nonlinear optimization, so that the center of mass and the motion trajectory of the foot meet the kinematic and dynamic constraints;

[0071] The center of mass and foot end motion trajectory are output to obtain the force and posture data of the robot leg structure in the working condition.

[0072] The motion trajectory planning of the amphibious crawling bionic robot in the diagonal gait and the tripod gait also includes: planning the motion trajectory of the robot in the diagonal gait and the tripod gait according to multiple movement speeds to obtain the force conditions more comprehensively.

[0073] In some specific embodiments, the preset force conditions for the lightweight design of the leg structure of an amphibious crawling bionic robot are as follows: the standing height of the leg structure is 0.16-0.20m, the force components of the foot end of the leg structure in two horizontal directions are 45-60N and 18-30N, and the force component in the vertical direction is 660-700N;

[0074] The preset constraint condition is specifically: the driving component is set as a fixed constraint surface. The single leg is connected to the fuselage mainly through the first joint motor 1. There are corresponding bolt connection holes on the upper and lower surfaces of the first joint motor 1. Therefore, the side of the first joint motor 1 close to the output shaft, that is, close to the 1-2 motor connector, can be set as a fixed constraint surface.

[0075] Furthermore, the lightweight leg structure model is strength checked, specifically including:

[0076] Finite element analysis is performed on the lightweight leg structure model under preset force conditions and preset constraint conditions to obtain strain information on the surface of the leg structure, and whether the strength requirements are met is determined based on the strain information. If the surface strain information is within the preset threshold range, it is considered that the strength requirements are met; if it exceeds the preset threshold range, it needs to be redesigned.

[0077] Furthermore, the software for establishing the leg structure solid model includes Solidworks three-dimensional software.

[0078] In some specific embodiments, the thigh length, i.e., the distance between the output shaft of the third joint motor 3 and the driven wheel shaft, is 180-220 mm; for example, it can be 200 mm. The initial thickness of the inner thigh plate 6 and the outer thigh plate 7 is 4-6 mm; for example, it can be 5 mm. The calf length, i.e., the distance between the calf shaft and the sole of the foot, is 180-220 mm; for example, it can be 200 mm.

[0079] The inner thigh plate 6, the outer thigh plate 7, the calf bone 10, the 1-2 motor connector, the 2-3 motor connector, the ball foot base 11, and the belt tensioner 9 are made of aluminum alloy 5454.

[0080] The design space is the outer thigh, inner thigh and calf.

[0081] The force conditions and constraints are set according to extreme working conditions, that is, the robot stands at a height of 0.182m, has a three-legged gait, and moves at a speed of 0.5m / s. The specific force at the foot end is 52.4115N in the x-direction, 24.4803N in the y-direction, and 685.7389N in the z-direction.

[0082] The relevant parameters of the grid structure are set according to the default data and actual conditions. The quality target is set to 80% of the total volume of the design space, and the frequency constraint is set to none.

[0083] Aiming at the problem that the existing robot leg structure has a large deadweight and affects its performance, the present invention discloses a lightweight design method for a lattice filling structure of an amphibious crawling bionic robot leg, comprising: establishing an initial model of the robot leg structure; performing hole opening, hole expansion and deletion design on local positions of the thigh and calf to obtain a preliminary designed leg structure; obtaining the working condition data of the robot leg in a diagonal gait and a three-legged gait respectively; importing the preliminary designed leg structure into Inspire software, setting the design space after checking whether the connection is correct, setting the load working condition and boundary constraint conditions; running optimization, selecting the grid structure as the type, setting the optimization target to maximize the stiffness, setting relevant parameters, and obtaining the final optimized robot leg structure; performing displacement and strength verification on the final structure to achieve the lightweight target of weight reduction and ensure its stiffness and manufacturability; reducing the leg weight and improving the manufacturing economy of the robot.

[0084] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An amphibious crawling bionic robot leg structure, characterized in that: It includes a driving component, a thigh component, a transmission component, a calf component and a sole component; the thigh component includes an inner thigh plate and an outer thigh plate which are arranged opposite to each other, the first end of the inner thigh plate and the first end of the outer thigh plate are respectively connected to the driving component and can rotate as a whole under the drive of the driving component; the calf component includes a calf bone, the top of the calf bone is rotationally connected between the second ends of the inner thigh plate and the outer thigh plate; the transmission component is arranged between the inner thigh plate and the outer thigh plate, and the transmission component is transmission-connected between the driving component and the calf bone, and can drive the calf bone to rotate under the drive of the driving component; the sole component is connected to the bottom of the calf bone, and the inner thigh plate, the outer thigh plate and the calf bone are set as a lattice structure.

2. The leg structure of an amphibious crawling bionic robot according to claim 1, characterized in that: The driving assembly includes a first joint motor, a second joint motor and a third joint motor; the first joint motor is used to be connected to the robot body, the output end of the first joint motor is connected to the second joint motor through the first motor connector, the output end of the second joint motor is connected to the third joint motor through the second motor connector, the output end of the third joint motor is connected to the transmission assembly, the second joint motor and the third joint motor are coaxial, the second joint motor is used to drive the thigh assembly to lift and retract the leg, and the third joint motor is used to drive the calf assembly to lift and retract the leg.

3. The leg structure of an amphibious crawling bionic robot according to claim 1, characterized in that: The transmission assembly is a synchronous belt assembly, which includes a driving wheel, a driven wheel and a transmission belt. The driving wheel is rotatably connected to the first end of the thigh assembly and is connected to the driving assembly. The driven wheel is rotatably connected to the second end of the thigh assembly and is integrally rotatably connected to the calf bone. The transmission belt is tensioned on the outside of the driving wheel and the driven wheel.

4. The leg structure of an amphibious crawling bionic robot according to claim 3, characterized in that: The synchronous belt assembly also includes a belt tensioner. Bosses are respectively provided on the opposite sides of the inner thigh plate and the outer thigh plate. The belt tensioner is arranged on the bosses to tension the transmission belt.

5. The leg structure of an amphibious crawling bionic robot as claimed in claim 3, characterized in that: The inner thigh plate is connected to the driving assembly on one side of the driving wheel, the first end of the outer thigh plate is connected to an arc-shaped connecting plate, and the outer thigh plate is connected to the driving assembly on the other side of the driving wheel through the arc-shaped connecting plate; The calf bone comprises two calf plates arranged opposite to each other and a reinforcing plate connected between the two calf plates.

6. The leg structure of an amphibious crawling bionic robot according to claim 1, characterized in that: The sole assembly comprises a ball foot base and a ball foot cover, the top of the ball foot base is connected to the bottom of the calf bone, the bottom of the ball foot base is spherical, and the ball foot cover is sleeved on the outside of the ball foot base.

7. A lightweight design method for the leg structure of an amphibious crawling bionic robot, characterized in that: Based on the leg structure of the amphibious crawling bionic robot according to any one of claims 1 to 6, the lightweight design method comprises: Design the shape and size of the leg structure and obtain an initial leg structure model; Designing a reduction hole for the initial leg structure model to obtain a reduced leg structure model; Under preset force conditions and preset constraint conditions, the reduced-weight leg structure model is subjected to a lattice filling design on the structures of the inner thigh plate, the outer thigh plate and the calf bone with maximizing stiffness as an optimization goal, so as to obtain a lightweight leg structure model; The lightweight leg structure model is strength-checked, and the lightweight design is completed after the check.

8. The lightweight design method for the leg structure of an amphibious crawling bionic robot according to claim 7, characterized in that: The preset stress condition is determined by the following method: The motion trajectory of the amphibious crawling bionic robot is planned in the diagonal gait and the tripod gait respectively, and the simulated motion is performed according to the corresponding gait according to the planned motion trajectory; Obtain the force conditions on the sole of the leg structure of the amphibian crawling bionic robot during the simulation movement; The maximum force condition of the sole during the simulated movement is selected as the preset force condition; The maximum stress condition includes the force magnitude and direction of the sole of the leg structure and the corresponding standing posture of the leg structure.

9. The lightweight design method for the leg structure of an amphibious crawling bionic robot according to claim 8, characterized in that: The preset force working condition is specifically: the standing height of the leg structure is 0.16-0.20m, the force components of the foot end of the leg structure in two horizontal directions are 45-60N and 18-30N, and the force component in the vertical direction is 660-700N; The preset constraint condition is specifically: setting the driving component as a fixed constraint surface.

10. The lightweight design method for the leg structure of an amphibious crawling bionic robot according to claim 7, characterized in that: The lightweight leg structure model is subjected to strength verification, specifically including: Finite element analysis is performed on the lightweight leg structure model under preset stress conditions and preset constraint conditions to obtain strain information on the surface of the leg structure, and it is determined whether the strength requirements are met based on the strain information.

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