A lizard-like robot adapted for soft sand

Abstract

The application belongs to the technical field of bionic robots, and particularly discloses a lizard-imitating robot suitable for soft sandy land, which comprises a foot, a leg, a spine, a head and a tail; the tail is connected to the tail end of the spine, the legs are symmetrically connected to the surface of the spine, and the foot is connected to the end of the leg; the foot comprises toes, a foot bottom, a foot shell and an ankle joint; the ankle joint is connected to the leg, the foot shell is connected to the end of the ankle joint, the surface of the foot shell is uniformly provided with the toes, and the foot bottom is arranged at the bottom end of the foot shell; the gear driving mechanism of the gear and the rack is adopted to drive the toes and the claw to move in the foot, compared with the traditional spring or rope driving, the mode can be actively controlled during the grabbing and releasing, the loss of the capability during the grabbing process is greatly reduced, the grabbing torque is larger and the transmission efficiency is higher, and in addition, the gear driving mechanism can prolong the service life of the robot.

Description

Technical Field

[0001] This invention relates to the field of biomimetic robot technology, specifically to a lizard-like robot adapted to soft sand. Background Technology

[0002] When faced with soft sandy terrain, such as deserts, swamps, or the surfaces of Mars or the Moon, ordinary wheeled or C-wheeled robots still pose a risk of sinking into the loose sand and have poor mobility in rugged desert terrain. Desert animals use multiple toes to stabilize the sand, improving their mobility in soft sand. Inspired by the free-crossing behavior of desert lizards, researchers have designed a variety of biomimetic robots.

[0003] Patent application CN202221633538.2 describes a lizard-like robot whose spine uses two servo motors to swing left and right. Its feet cannot actively grip the ground, resulting in low mobility. Patent application CN202222983971.5 proposes a lizard-like robot with a rope-driven spine that swings in sync with leg movements. However, it lacks toes, making it unstable on unstructured surfaces. Patent application CN202211702422.4 proposes a biomimetic lizard robot with a flexible, active spine and multiple toes. In addition to two servo motors for swinging, two more servo motors adjust the spine's height above the ground. The flexible toes can actively grip the ground, enabling walking on soft and rough surfaces. However, because the toes use springs to transmit torque, the gripping torque is relatively small, resulting in weak climbing ability. Furthermore, the robot's spinal and leg joints are not robust, leading to poor overall robot stability.

[0004] Recently, patent application number 202311461322.1 disclosed a standing, crawling lizard-like robot. By actively swinging its spine and moving up and down, the robot's stability on uneven surfaces is improved. Foot motors drive suction cups to adhere to and detach from walls, and electric cylinders and motors enable the robot to walk on vertical walls. However, the robot's feet have weak adhesion to soft sand, making it unsuitable for soft sandy terrain.

[0005] Therefore, current lizard-like robots cannot yet achieve stable movement on soft sandy slopes. It is necessary to improve the gripping force of the robot's feet, its ability to climb soft, broken surfaces, and the stability of the overall structure, thereby improving the biomimetic robot's ability to move on surfaces such as deserts and earthquake zones. Summary of the Invention

[0006] The purpose of this invention is to provide a lizard-like robot adapted to soft sandy terrain, in order to solve the problems mentioned in the background art.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a lizard-like robot adapted to soft sand, comprising feet, legs, a spine, a head, and a tail; the tail is connected to the end of the spine, legs are symmetrically connected to the surface of the spine, and feet are connected to the ends of the legs; the feet include toes, soles, a foot shell, and an ankle joint; the ankle joint is connected to the legs, the foot shell is connected to the end of the ankle joint, toes are evenly distributed on the surface of the foot shell, and a sole is provided at the bottom end of the foot shell;

[0008] The toe includes a servo housing; a servo is installed inside the servo housing, a gear servo disk is connected to the surface of the servo output shaft, a gear transmission mechanism is provided on the surface of the gear servo disk, the other end of the gear transmission mechanism is connected to the claw spike, the claw spike has a triangular structure, the gear transmission mechanism includes a pinion and a transmission gear; the rear end of the claw spike is connected to the pinion, and two transmission gears are arranged sequentially on the rear side of the pinion, the pinion and the two transmission gears are meshed and connected in sequence.

[0009] Preferably, a slider is provided at the rear end of the transmission gear located at the rear. The axles of the claw, the pinion, and the transmission gear are all fixed to the surface of the toe shell. A toe gear is provided at the rear end of the toe shell. The toe gear has the same module as the transmission gear, and the gear ratio between the toe gear and the transmission gear is 17:11.

[0010] Preferably, the slider has a semi-circular structure, with external racks evenly distributed on the surface of the slider corresponding to the toe gear and the transmission gear. Two identical internal racks are symmetrically distributed inside the slider. Support rods are provided at the middle positions of the upper and lower ends of the slider corresponding to the external racks, and rollers are provided on the surface of the support rods.

[0011] Preferably, the upper part of the sole is a semi-circular structure, the lower part is an elliptical structure, the bottom of the sole is a curved transition, and the lower part of the sole is provided with a circular arc protrusion.

[0012] Preferably, the ankle joint includes an ankle joint end cap; the top of the foot shell is provided with an ankle joint end cap, the surface of the ankle joint end cap is provided with a flange, the ankle joint end cap and the flange are connected to each other by a bearing, a pressure cap is provided on the outside of the flange, a connecting rod is provided on the surface of the flange, and the other end of the connecting rod is connected to the leg.

[0013] Preferably, the leg includes a calf; one end of the calf is connected to the foot, and the other end of the calf is internally connected to the thigh, and the calf and thigh are rotatably connected; the other end of the thigh is provided with a cross-shaped bracket, the upper and lower ends of the cross-shaped bracket are provided on the upper and lower surfaces of the thigh, a four-bar linkage is connected to the surface of the cross-shaped bracket, and support rods are connected to both sides of the four-bar linkage; the four-bar linkage is connected to the spine through the support rods.

[0014] Preferably, the spine includes a mid-spine; spinal ends are symmetrically arranged on the anterior and posterior sides of the mid-spine, and the spinal ends are connected to the mid-spine via a spinal support; electronic devices are installed inside the mid-spine, and batteries are installed on both sides inside the mid-spine; spinal servos are symmetrically installed at both ends of the mid-spine, and the spinal servos are fixed inside the spinal servo housing, with a spinal servo shaft provided on the surface of the spinal servo housing.

[0015] Preferably, a baffle is provided on the end face of the spine, and the two ends of the spine are respectively connected to the head and the tail, and the head and the tail are designed to resemble the structure of a desert lizard.

[0016] Compared with the prior art, the beneficial effects of the present invention are:

[0017] 1. This invention uses a gear drive mechanism with a rack and pinion to drive the movement of the toes and claws in the foot. Compared with the traditional spring or rope drive, this method can be actively controlled during grasping and releasing, which greatly reduces the loss of energy during the grasping process. The grasping torque is large and the transmission efficiency is high. Furthermore, the use of a gear drive mechanism can extend the service life of the robot.

[0018] 2. This invention places the servo motor that controls the ankle twisting inside the calf, lowering the leg's center of gravity and making walking more stable. The sole of the foot is designed as a wide oval, increasing the contact area and helping to reduce pressure. The sole of the foot is also designed with stripes to increase friction. Furthermore, the foot and leg are designed as a closed structure, which can reduce the entry of particles.

[0019] 3. The present invention uses a spinal support to symmetrically arrange two spinal servos, making the connection structure between the middle and end of the spine more compact. This increases the stability of the spine while ensuring flexibility of movement. An annular end cap is provided at the end of the spinal support to ensure uniform and stable torque transmission in each joint.

[0020] 4. The robot of this invention can move steadily in a straight line and turn in place on soft sand. When moving forward with a diagonal gait, its speed can reach 28.1 mm / s. When climbing, it adopts a triangular gait and keeps its spine in contact with the slope when lifting its legs. The maximum climbing slope is 28°, corresponding to a slip rate of 76.8%. Attached Figure Description

[0021] Figure 1 A schematic diagram of the overall structure of a lizard-like robot adapted to soft sand provided by the present invention;

[0022] Figure 2 A schematic diagram of the structure of a lizard-like robot toe adapted to soft sand provided by the present invention;

[0023] Figure 3A schematic diagram of the ankle joint of a lizard-like robot adapted to soft sand provided by the present invention;

[0024] Figure 4 A schematic diagram of the structure of a lizard-like robot leg adapted to soft sand provided by the present invention;

[0025] Figure 5 A schematic diagram of the spine of a lizard-like robot adapted to soft sand provided by the present invention.

[0026] In the diagram: 1. Foot; 11. Toe; 12. Foot sole; 13. Foot shell; 14. Ankle joint; 11a. Claw; 11b. Gear transmission mechanism; 11c. Toe shell; 11d. Slider; 11e. Roller; 11f. Servo; 11g. Servo housing; 11h. Gear rudder; 14a. Ankle joint end cap; 14b. Bearing; 14c. Linkage; 14d. Flange; 14e. Pressure cap; 2. Leg; 21. Lower leg; 22. Thigh; 23. Four-bar linkage; 24. Cross-shaped bracket; 25. Support link; 3. Spine; 31. Spine support; 31a. Spine servo housing; 31b. Spine servo shaft; 32. Mid-spine; 33. Electronic components; 34. Battery; 35. Baffle; 36. End of spine; 41. Head; 42. Tail. Detailed Implementation

[0027] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] In the description of this invention, it should be noted that the terms "vertical," "upper," "lower," "horizontal," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0029] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0030] like Figures 1-5 As shown; the present invention provides a lizard-like robot adapted to soft sand, including a foot 1, a leg 2, a spine 3, a head 41, and a tail 42; the tail 42 is connected to the end of the spine 3, the leg 2 is symmetrically connected to the surface of the spine 3, and the foot 1 is connected to the end of the leg 2; the foot 1 includes toes 11, a sole 12, a foot shell 13, and an ankle joint 14; the ankle joint 14 is connected to the leg 2, the foot shell 13 is connected to the end of the ankle joint 14, the toes 11 are evenly distributed on the surface of the foot shell 13, and the sole 12 is provided at the bottom of the foot shell 13;

[0031] The toe 11 includes a servo housing 11g; a servo motor 11f is installed inside the servo housing 11g; a gear servo disk 11h is connected to the output shaft surface of the servo motor 11f; a gear transmission mechanism 11b is provided on the surface of the gear servo disk 11h; the other end of the gear transmission mechanism 11b is connected to a claw 11a; the claw 11a has a triangular structure; the gear transmission mechanism 11b includes a pinion and a transmission gear; a pinion is connected to the rear end of the claw 11a; two transmission gears are sequentially arranged behind the pinion; the pinion and the two transmission gears are sequentially meshed and connected.

[0032] The rear end of the transmission gear located at the rear is provided with a slider 11d. The axles of the claw 11a, the pinion, and the transmission gear are all fixed to the surface of the toe 11 shell. The rear end of the toe 11 shell is provided with a toe 11 gear. The toe 11 gear has the same module as the transmission gear, and the gear ratio between the toe 11 gear and the transmission gear is 17:11.

[0033] The slider 11d has a semi-circular structure. The surface of the slider 11d is evenly distributed with external racks corresponding to the toe 11 gear and the transmission gear. The slider 11d has two identical internal racks symmetrically distributed inside. The upper and lower ends of the slider 11d are provided with support rods at the middle positions corresponding to the external racks. The surface of the support rods is provided with rollers 11e. The rollers 11e are in contact with the slide rail of the foot 1, thereby reducing the friction when the slider 11d slides in the foot 1 and restricting the degree of freedom of the slider 11d in the rotation direction.

[0034] The gear transmission mechanism 11b meshes with the racks on both sides inside the slider 11d. To ensure the accuracy of the gear meshing, a rectangular baffle 35 is added to the end face of the gear to fix the gear shaft. This converts the rotation of the servo motor 11f into the up-and-down movement of the slider 11d. The up-and-down movement of the slider 11d drives the foot 1 to grasp and release. When grasping, the toes 11 and the claws 11a move simultaneously. First, the claws 11a contact the soft ground, and then the entire toe 11 is inserted into the ground, making the foot 1 firmly fixed. When releasing, the servo motor 11f only needs to be reversed.

[0035] The upper part of the foot 12 is a semi-circular structure, and the rear part is an elliptical structure. The bottom of the foot 12 adopts an arc transition. This design can increase the contact area with the ground while retaining the placement position of the servo motor 11f, so as to reduce the pressure on the foot 1. The lower part of the foot 12 is provided with an arc strip protrusion, which can increase the adhesion of the foot 1 on soft ground.

[0036] The ankle joint 14 includes an ankle joint end cap 14a; the top of the foot shell 13 is provided with an ankle joint end cap 14a, the surface of the ankle joint end cap 14a is provided with a flange 14d, the ankle joint end cap 14a and the flange 14d are connected to each other by a bearing 14b, a pressure cap 14e is provided on the outside of the flange 14d, a connecting rod 14c is provided on the surface of the flange 14d, and the other end of the connecting rod 14c is connected to the leg 2;

[0037] By moving the servo motor 11f, which was originally located at the ankle joint 14, to the leg 2, and then using the linkage 14c to drive the rotation of the foot 1, the height of the foot 1 is reduced.

[0038] The leg 2 includes a lower leg 21; one end of the lower leg 21 is connected to the foot 1, and the other end of the lower leg 21 is internally connected to the thigh 22, and the lower leg 21 and the thigh 22 are rotatably connected. The other end of the thigh 22 is provided with a cross-shaped bracket 24. The upper and lower ends of the cross-shaped bracket 24 are provided on the upper and lower surfaces of the thigh 22. A four-bar linkage 23 is connected to the surface of the cross-shaped bracket 24. Supporting rods 25 are connected to both sides of the four-bar linkage 23. The four-bar linkage 23 is connected to the spine 3 through the supporting rods 25.

[0039] The hip joint at the connection between leg 2 and spine 3 is decomposed into two degrees of freedom. One is the swinging hip joint, which uses a four-bar linkage 23 to swing up and down to achieve the vertical rise and fall of leg 2, so that the sole of foot 12 remains parallel to the ground, which is conducive to foot 1 contacting the ground and grasping. The other is the rotational hip joint, which, together with the knee joint, controls leg 2 to rotate on a plane parallel to the support plane. At the same time, the strength of the four-bar linkage 23 is strengthened to reduce energy loss due to friction. A support link 25 is added between the upper and lower layers of the four-bar linkage. The four-bar linkage 23 is connected to the cross-shaped bracket 24 or the connecting shaft of the spinal end 36 through bearings and sealed with a baffle 35 to reduce the entry of dust.

[0040] The spine 3 includes a mid-spine segment 32; the mid-spine segment 32 is symmetrically provided with spinal end segments 36 on both the front and rear sides, and the spinal end segments 36 and the mid-spine segment 32 are connected to each other by a spinal support 31; electronic devices 33 are installed inside the mid-spine segment 32, and batteries 34 are installed on both sides inside the mid-spine segment 32; spinal servo motors are symmetrically installed at both ends of the mid-spine segment 32, and the spinal servo motors are fixed inside the spinal servo motor housing 31a, and a spinal servo motor shaft 31b is provided on the surface of the spinal servo motor housing 31a.

[0041] A baffle 35 is provided on the end face of the end of the spine 36, and the two ends of the spine 3 are respectively connected to the head 41 and the tail 42, which are designed to resemble the structure of a desert lizard.

[0042] Two spinal servos are symmetrically arranged on both sides of the spine 3 via a spinal support 31. The spinal support 31 has a cross-shaped structure and is sealed with an annular end cap at the end. The connected spinal servo housing 31a uses a boss and bearing mechanism to transfer the load of each joint to each component structure. The spinal servo shaft 31b is only used for the output of torsional torque to ensure the uniformity and stability of the force on each joint. The interior of the middle section 32 of the spine is the load-bearing area, which is used to support the electronic devices 33 and batteries 34 of each module of the robot.

[0043] like Figures 1-5 As shown, this invention provides a lizard-like robot adapted to soft sand. The robot's overall length, width, and height are 741mm, 378mm, and 105mm, respectively. To ensure relatively easy control, the robot is designed symmetrically, with a thigh-to-lower-leg ratio of 1:1.3 and a thigh-to-spine ratio of 1:4.4. The robot's structural components are manufactured using 3D printing with 8200pro resin, which possesses extremely high toughness, a tensile strength of 52.3 MPa, a low yield strain of 3.4%, and a density of 1130 kg / m³. 3The printing accuracy is ±200μm, which is sufficient for verifying the robot model structure. However, for the grasping components of foot 1 and the supporting components of spine 3, higher structural strength and greater resistance to bending deformation are required. Therefore, 7200 nylon fiber-reinforced material was selected, which has a bending strength of 65Mpa and a density of 1150Kg / m³. 3 Meanwhile, it also has relatively high performance in terms of tensile strength and heat resistance. The screw size used for the internal connection of the leg 2 structure is M2×5, the screw size between the leg structure and the servo motor 11f is M3×8, and the bolt size used for the spine 3 structure is M3×10.

[0044] The spinal servo housing 31a has a bus servo 11f interface on its surface for connecting the LX-224HV high-voltage serial bus servo 11f. A single spinal servo weighs 62g, operates at 9-12V, has a maximum torque exceeding 20Kg / cm, a response speed of 3ms / °, and a control accuracy of 0.3°. The servo 11fs are connected in series, greatly reducing wiring complexity, making it suitable for driving robot joints. The control system uses a Raspberry Pi 4B board as the control center, along with the servo 11f control board and power supply. The Raspberry Pi itself has… The host computer system and built-in WiFi module can connect to the Raspberry Pi's built-in host computer via WiFi during operation. The host computer can program and control other peripherals connected to the Raspberry Pi. It can realize remote wireless connection and real-time control of the robot's movement status. The MPU6050 module of the servo motor 11f board is used to detect changes in the robot's body tilt angle. Since the robot has many joint angles, a large number of servo motor 11f are required. Therefore, the required battery current is large. A battery with a 10x amplification factor and a capacity of 2500mAh is selected for power supply.

[0045] The robot foot 1 of this invention has a large torque, a compact structure, and can adapt to various gaits such as walking, running, turning, and climbing. It has stable movement and its size proportions are more similar to those of a lizard. Using simulated Martian soil, a traversal experiment was conducted, and the maximum forward speed was measured to be 28.1 mm / s. When climbing a slope, the spine is in contact with the slope surface, and the maximum slope angle was measured to be 28°, corresponding to a slip rate of 76.8%.

[0046] It is worth noting that the entire device is controlled by a master control button. Since the device matched with the control button is a common device and belongs to existing common knowledge technology, its electrical connection relationship and specific circuit structure will not be described in detail here.

[0047] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A lizard-like robot adapted to soft sand, characterized in that: It includes a foot (1), a leg (2), a spine (3), a head (41), and a tail (42); the tail (42) is connected to the end of the spine (3), the leg (2) is symmetrically connected to the surface of the spine (3), and the foot (1) is connected to the end of the leg (2); the foot (1) includes toes (11), sole (12), foot shell (13), and ankle joint (14); the ankle joint (14) is connected to the leg (2), the foot shell (13) is connected to the end of the ankle joint (14), the toes (11) are evenly arranged on the surface of the foot shell (13), and the sole (12) is arranged at the bottom of the foot shell (13); The toe (11) includes a servo housing (11g); a servo (11f) is installed inside the servo housing (11g), and a gear servo disk (11h) is connected to the output shaft surface of the servo (11f). A gear transmission mechanism (11b) is provided on the surface of the gear servo disk (11h), and the other end of the gear transmission mechanism (11b) is connected to a claw (11a). The claw (11a) has a triangular structure, and the gear transmission mechanism (11b) includes a pinion and a transmission gear. A pinion is connected to the rear end of the claw (11a), and two transmission gears are arranged sequentially on the rear side of the pinion. The pinion and the two transmission gears are meshed sequentially. A slider (11d) is provided at the rear end of the transmission gear located at the rear. The axles of the claw (11a), the pinion, and the transmission gear are all fixed to the surface of the toe (11) housing. A toe (11) gear is provided at the rear end of the toe (11) housing, and the slider (11d) has a semi-circular structure. The surface of the slider (11d) is uniformly distributed with external racks corresponding to the toe (11) gear and the transmission gear. The slider (11d) has two identical internal racks symmetrically distributed inside. The upper and lower ends of the slider (11d) are provided with support rods at the middle positions of the external racks. The surface of the support rods is provided with rollers (11e). The leg (2) includes a calf (21). One end of the calf (21) is connected to the foot (1). The other end of the calf (21) is internally connected to the thigh (22), and the calf (21) and the thigh (22) are rotatably connected. The other end of the thigh (22) is provided with a cross-shaped bracket (24). The upper and lower ends of the cross-shaped bracket (24) are provided on the upper and lower surfaces of the thigh (22). The surface of the cross-shaped bracket (24) is connected with a four-bar linkage (23). The four-bar linkage (23) is connected to the two sides of the four-bar linkage (23) with support rods (25). The four-bar linkage (23) is connected to the spine (3) through the support rods (25).

2. The lizard-like robot adapted to soft sand as described in claim 1, characterized in that: The toe (11) gear has the same module as the transmission gear, and the gear ratio of the toe (11) gear to the transmission gear is 17:

11.

3. The lizard-like robot adapted to soft sand as described in claim 1, characterized in that: The upper part of the foot sole (12) is a semi-circular structure, the lower part is an elliptical structure, the bottom of the foot sole (12) adopts an arc transition, and the lower part of the foot sole (12) is provided with an arc strip protrusion.

4. A lizard-like robot adapted to soft sand as described in claim 1, characterized in that: The ankle joint (14) includes an ankle joint end cap (14a); the top of the foot shell (13) is provided with an ankle joint end cap (14a), the surface of the ankle joint end cap (14a) is provided with a flange (14d), the ankle joint end cap (14a) and the flange (14d) are connected to each other by a bearing (14b), a pressure cap (14e) is provided on the outside of the flange (14d), a connecting rod (14c) is provided on the surface of the flange (14d), and the other end of the connecting rod (14c) is connected to the leg (2).

5. A lizard-like robot adapted to soft sand as described in claim 1, characterized in that: The spine (3) includes a mid-spine segment (32); the mid-spine segment (32) has symmetrically arranged spinal ends (36) on both the front and rear sides, and the spinal ends (36) and the mid-spine segment (32) are connected to each other by a spinal support (31). Electronic devices (33) are installed inside the mid-spine segment (32), and batteries (34) are installed on both sides inside the mid-spine segment (32). Spinal servos are symmetrically installed at both ends of the mid-spine segment (32), and the spinal servos are fixed inside the spinal servo housing (31a). A spinal servo shaft (31b) is provided on the surface of the spinal servo housing (31a).

6. A lizard-like robot adapted to soft sand as described in claim 5, characterized in that: The end face of the spinal end (36) is provided with a baffle (35), and the two ends of the spinal column (3) are respectively connected to the head (41) and the tail (42), and the head (41) and the tail (42) are designed to resemble the structure of a desert lizard.

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