A wheel-foot conversion device and a robot

Abstract

The utility model discloses a wheel foot conversion device and a robot. The wheel foot conversion device comprises a robot calf, the robot calf is connected with the robot thigh, and a supporting foot (7) is fixedly arranged at the lower end of the robot calf, the supporting foot (7) is used for contacting with the ground to support the robot, a roller screw unit, which comprises a screw (2), a screw nut (3) and a screw motor (4), both ends of the screw (2) are connected to the robot calf, the screw motor (4) is in transmission connection with the screw (2), is used for driving the forward rotation and reverse rotation of the screw (2), thereby drives the forward movement or reverse movement of the screw nut (3) along the screw (2), a roller is connected on the screw nut (3), the roller moves along the axis of the screw (2) together with the screw nut (3), to realize the switching between the wheel type support and the foot type support.

Description

Technical Field

[0001] This utility model relates to the field of robotics, and in particular to a wheel-leg conversion device and a robot having the same. Background Technology

[0002] Wheeled-legged robots can travel at high speeds on relatively flat surfaces, improving work efficiency. Legged robots are better able to adapt to complex terrain. Wheeled-legged robots combine the advantages of both wheeled and legged robots, better meeting on-site usage requirements. The wheel-leg switching device is a key component for wheeled-legged robots to switch between wheeled and legged support modes.

[0003] In existing technologies, wheel-foot conversion devices typically employ linkage mechanisms, rack and pinion mechanisms, or screw drives to drive the relative movement between the support wheel and the support foot. These driving methods have drawbacks such as requiring large installation space and lacking self-locking capabilities. Therefore, Chinese Patent 202210646153.8 (Authorization Announcement No. CN 114919675 B, Invention Title: A Wheel-Foot Conversion Mechanism and Its Control Method) utilizes a lead screw structure to drive the wheel-foot conversion.

[0004] See Figure 1 and Figure 2 In the prior patent, the support foot rotates with the support wheel. During wheel-foot switching, the support wheel needs to be rotated to a specific position so that the support foot faces downwards. This reduces the efficiency of wheel-foot switching and requires precise control of the support wheel's rotation angle. Furthermore, it limits the shape and size of the support foot, making it difficult to meet the requirements of complex terrain. In addition, because the lead screw structure axially passes through the roller, it is impossible to install roller support spokes at the lead screw structure, adversely affecting the roller's strength.

[0005] Therefore, it is desirable to have a technical solution to overcome or at least mitigate at least one of the aforementioned defects of the prior art. Utility Model Content

[0006] The purpose of this invention is to provide a wheel-foot conversion device to overcome or at least mitigate at least one of the aforementioned defects of the prior art.

[0007] To achieve the above objectives, this utility model provides a wheel-foot conversion device, the wheel-foot conversion device comprising:

[0008] The robot's lower leg is connected to the robot's thigh, and a support foot is fixedly installed at the lower end of the robot's lower leg. The support foot is used to contact the ground to support the robot.

[0009] A ball screw unit, comprising a ball screw, a ball screw nut, and a ball screw motor.

[0010] The two ends of the lead screw are connected to the robot's lower legs.

[0011] The lead screw motor is connected to the lead screw drive and is used to drive the lead screw to rotate in the forward and reverse directions, thereby driving the lead screw nut to move along the lead screw in the forward or reverse direction.

[0012] A roller is connected to the lead screw nut, and the roller moves along the axis of the lead screw together with the lead screw nut to realize the switching between wheel support and foot support.

[0013] Preferably, the wheel-leg conversion device includes two guide rods, which are arranged parallel to the lead screw and are respectively fixedly connected at both ends to the lower leg skeleton of the robot's lower leg. A connecting plate is fixedly connected to the lead screw nut, and the connecting plate has a sliding hole that slides with the outer periphery of the guide rod.

[0014] Preferably, an electric gripper is installed on the connecting plate. The electric gripper has an open state and a clamping state. In the clamping state, the electric gripper holds the guide rod and prevents the connecting plate from sliding relative to the guide rod. In the open state, the electric gripper releases the guide rod and allows the connecting plate to slide relative to the guide rod.

[0015] Preferably, when powered on, the electric gripper is in the open state, and when de-powered, the electric gripper is in the clamping state.

[0016] Preferably, two electric grippers are installed on the connecting plate, with one electric gripper corresponding to each guide rod.

[0017] Preferably, the foot body of the supporting foot includes a semi-cylindrical portion and a quarter-spherical portion connected at the front and rear ends of the semi-cylindrical portion; a central through hole is provided at the middle position of the foot body to allow the roller to pass through.

[0018] Preferably, two symmetrical gripping toes are provided on the lower side of the semi-cylindrical portion, the foot body is integrally formed, the gripping toes are installed onto the foot body in a replaceable manner, and the gripping portion of the gripping toes is hemispherical.

[0019] Preferably, the foot of the supporting foot is hemispherical, and the roller is placed side by side with the supporting foot in the left-right direction.

[0020] Preferably, the roller is a Mecanum roller, and its drive motor is mounted on the hub.

[0021] This utility model also provides a robot, which includes the wheel-leg conversion device as described above. The robot is a hexapod robot, and the wheel-leg conversion device is installed only on the robot legs located on the left front, left rear, right front, and right rear. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of a wheel-foot conversion device in the prior art, in which the supporting foot is facing the ground.

[0023] Figure 2 yes Figure 1 Another schematic diagram of the wheel-foot conversion device is shown, in which the support foot rotates with the roller to a position away from the ground.

[0024] Figure 3 This is a schematic diagram of a wheel-foot conversion device according to an embodiment of the present invention, in which the roller and roller mounting bracket are omitted.

[0025] Figure 4 This is a bottom view of the supporting foot of the wheel-foot conversion device according to another embodiment of the present invention.

[0026] Figure 5 for Figure 4 The diagram shows a view of the supporting foot from below and from the front.

[0027] Figure label:

[0028] 1. Lower leg frame; 2. Lead screw; 3. Lead screw nut; 4. Lead screw motor; 5. Guide rod; 6. Connecting plate; 7. Support foot; 11. Pivot connection hole; 12. Drive component connection hole; 13. Reinforcing component connection hole; 71. Foot body; 72. Central through hole; 73. Gripping toe; 74. Quarter-spherical part; 75. Semi-cylindrical part; 76. Support rib; Detailed Implementation

[0029] In the accompanying drawings, the same or similar reference numerals are used to denote the same or similar elements or elements having the same or similar functions. The embodiments of this utility model will now be described in detail with reference to the accompanying drawings.

[0030] In the description of this utility model, the terms "center", "longitudinal", "lateral", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" 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 utility model 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 the scope of protection of this utility model.

[0031] The wheel-leg conversion device according to an embodiment of the present invention is used to enable wheel-leg conversion in robots. For example, the wheel-leg conversion device according to an embodiment of the present invention is used in a hexapod robot. The hexapod robot adopts biomimetic spider legs, and each leg is equipped with three servo motors to achieve high-precision joint angle control.

[0032] The robot in question is, for example, a fire monitoring robot. This robot can integrate multiple sensors to monitor environmental information in real time. For instance, it can be equipped with distance, collision, and ground detection sensors to provide information on obstacle distances and ground conditions, helping the robot avoid collisions. It can also be equipped with a 6mm wide-angle camera and an infrared thermal imager to capture visible light and thermal images respectively, enabling it to locate fire sources even in dense smoke.

[0033] The robot's main body utilizes biomimicry, taking the physiological structure of a spider as its basis, and imitating the spider's movement principles and behavior.

[0034] In terms of robot leg design, the degrees of freedom and range of motion of the legs play a decisive role in its mobility and adaptability. Generally, the more degrees of freedom a single leg has, the stronger the robot's movement ability will be; however, this also increases the complexity of the structure and the difficulty of control. For the leg design, we adopted an open-chain mechanism. The robot has six legs, with three servo motors assembled in each leg to achieve three rotational degrees of freedom, for a total of 18 servo motors. The motors are mounted at the hip joint and knee joint. At the hip joint, the thigh drive motors are centrally arranged. This design concentrates the leg mass in the torso, reducing the rotational inertia of the legs. The motors at this location allow the legs to swing left and right in the horizontal plane, enabling the robot to change its forward direction or move laterally. The motors at the knee joint control the flexion and extension of the legs, allowing the robot to adjust the leg span to adapt to different terrains.

[0035] High-quality shock absorption design is crucial for the stability and lifespan of a six-legged robot in complex terrain environments. For shock absorption, we first install thick rubber pads on the bottom of the feet. When the feet touch the ground, these pads cushion the impact, reducing vibrations transmitted to the leg structure and body. Secondly, we incorporate spring shock absorbers in the robot's lower legs, mounting the feet on guide rails on the side plates of the lower legs. When the feet are compressed, displacement occurs on the guide rails, transmitting the force to the springs. The springs then deform elastically, absorbing and dispersing energy, thus providing shock absorption. This also allows the legs to adapt to changes in ground surface during movement.

[0036] The wheels, for example, are Mecanum wheels, with all four wheels driven by independent motors, enabling movement in any direction within a plane. That is, in one embodiment, the wheel-foot conversion device is only installed on the robot feet located at the left front, left rear, right front, and right rear. The left center and right center robot feet use only foot-type support without rollers to simplify the structure.

[0037] In this utility model, "front" refers to the front of the robot, and "rear" refers to the rear of the robot. For example, in Figure 4 In the middle, the top is "front" and the bottom is "back"; the "left" and "right" in the picture are the same as the "left" and "right" in the text.

[0038] The robot employs the Mecanum wheel technology for wheeled movement. This technology allows the robot to move in any direction within a plane without changing the wheel's orientation, including forward, lateral, diagonal, and rotational movements, as well as combinations thereof. The principle is that rollers are mounted on the wheel rim at a 45-degree angle. When the wheel rotates, the lateral forces generated by the rollers cancel each other out, and the remaining force propels the vehicle in a specific direction. By individually controlling the speed and direction of each wheel, the robot can achieve complex movement paths.

[0039] The robot is equipped with four Mecanum wheels, two left-handed and two right-handed, arranged in a chiral symmetrical manner. This design is particularly suitable for operations in environments with limited space and narrow access routes, such as fire scenes in low-rise buildings. The robot can easily achieve omnidirectional movement without changing the direction of the wheels, greatly improving its mobility and flexibility in complex environments. This design enables the robot to respond quickly and perform various rescue tasks, while improving work efficiency and space utilization.

[0040] As shown in the figure, the wheel-leg conversion device of this utility model embodiment includes: robot lower leg and roller screw unit.

[0041] The robot's lower leg is connected to its upper leg, and a support foot 7 is fixedly mounted at the lower end of the lower leg. The support foot 7 is used to contact the ground to support the robot. The support foot 7 can be fixed to the robot's lower leg using any suitable structure. Optionally, the support foot 7 is fixedly mounted to the lower end of the lower leg frame 1. The specific structure of the support foot 7 and the lower leg frame 1 is not limited to the illustrated embodiment, but can adopt any suitable structure and shape. Advantageously, the lower leg frame 1 adopts a frame structure.

[0042] See Figure 3The lower leg skeleton 1 has a roughly U-shaped structure, with a pivot connection hole 11, a drive component connection hole 12, and a reinforcing component connection hole 13. The pivot connection hole 11 is used to pivotally connect the lower leg skeleton 1 to the robot's thigh (not shown). The drive component connection hole 12 is used to connect to a drive component, which is used to drive the lower leg to swing relative to the thigh. A specific driving method could be, for example, a linkage.

[0043] The reinforcing member connection hole 13 is used to install a rod-shaped or plate-shaped reinforcing member, so that the entire lower leg forms a closed annular structure, providing overall rigidity. The reinforcing member is, for example, a straight rod or plate, which may have a U-shaped cross-section to further improve strength.

[0044] The ball screw unit is used to achieve wheel-foot switching; that is, the wheel and foot are switched via a ball screw, which is driven by a motor to achieve the switching between wheeled and footed movement modes. By rotating the motor forward and reverse, the wheel moves closer to or further away from the ground, completing the mode switching to adapt to different terrains. The self-locking and rigidity advantages of the ball screw ensure structural stability under high loads or impact conditions, reducing the risk of failure due to switching failures, making it particularly suitable for applications in extreme environments such as fire rescue.

[0045] Specifically, the roller screw unit is used to drive the roller to move up and down. As shown in the figure, the roller screw unit includes a screw 2, a screw nut 3, and a screw motor 4. The specific specifications and models of the screw 2, screw nut 3, and screw motor 4 can be selected as needed.

[0046] The two ends of the lead screw 2 are connected to the robot's lower leg. Specifically, the two ends of the lead screw 2 are rotatably connected to the crossbar of the lower leg skeleton 1.

[0047] The lead screw motor 4 is connected to the lead screw 2 for driving the lead screw 2 to rotate in the forward and reverse directions, thereby driving the lead screw nut 3 to move along the lead screw 2 in the forward or reverse direction. Forward and reverse rotation are, for example, clockwise and counterclockwise rotation. Forward or reverse movement is, for example, upward and downward movement.

[0048] For example, when the motor rotates forward, the slider moves the wheels closer to the ground, switching from legged to wheeled movement. Conversely, when the motor rotates backward, the wheels retract, switching back to legged movement. When monitoring a fire, the robot moves at high speed on flat ground using its rolling wheels, quickly locating the fire and transmitting data back to the central system in real time. When encountering obstacles, the motor reverses, switching the robot to a legged gait. This improved performance in complex environments significantly reduced fire monitoring time, preventing the fire from spreading.

[0049] A roller (not shown) is connected to the lead screw nut 3. The roller moves along the axis of the lead screw 2 together with the lead screw nut 3 to achieve switching between wheel support and foot support.

[0050] The wheel-leg conversion device includes two guide rods 5, which are parallel to the lead screw 2 and fixedly connected at both ends to the lower leg skeleton 1 of the robot's lower leg. A connecting plate 6 is fixedly connected to the lead screw nut 3, and the connecting plate 6 has sliding holes that slide in contact with the outer circumference of the guide rods 5. This improves the stability of the roller's translation.

[0051] The specific shape of the connecting plate 6 and its fixed connection method with the lead screw nut 3 can be set as needed, and are not limited to the illustrated embodiment.

[0052] Understandably, the roller is connected to the connecting plate via a roller mounting bracket, and moves with the lead screw nut to achieve wheel foot conversion.

[0053] To improve locking performance, an electric gripper (not shown) is installed on the connecting plate 6. The electric gripper has an open state and a clamping state. In the clamping state, the electric gripper holds the guide rod 5 tightly, preventing the connecting plate 6 from sliding relative to the guide rod 5. In the open state, the electric gripper releases the guide rod 5, allowing the connecting plate 6 to slide relative to the guide rod 5.

[0054] In one optional embodiment, the electric gripper is in the open state when powered on, and in the clamping state when de-powered.

[0055] Two motorized locking jaws are installed on the connecting plate 6, with one motorized locking jaw corresponding to each guide rod 5. This allows for better locking.

[0056] See Figure 4 and Figure 5 The foot body 71 of the supporting foot 7 includes a semi-cylindrical portion 75 and a quarter-spherical portion 74 connected to the front and rear ends of the semi-cylindrical portion 75; a central through hole 72 is provided at the middle position of the foot body to allow the roller to pass through. Thus, both the supporting foot and the roller are located directly below the lower leg frame 1, providing better load-bearing performance. A rubber layer can be provided on the surface of the foot body to improve cushioning and wear resistance. The radius of the quarter-spherical portion 74 is the same as the radius of the semi-cylindrical portion 75, thus ensuring a smooth transition between the two. The length of the semi-cylindrical portion 75 can be set as needed, typically less than or equal to the radius of the semi-cylindrical portion 75.

[0057] Two symmetrical gripping toes 73 are provided on the lower side of the semi-cylindrical portion 75. The foot body 71 is integrally formed, and the gripping toes 73 are replaceably installed on the foot body 71. The gripping portion of the gripping toes 73 is hemispherical. A rubber layer can be provided on the surface of the gripping toes to improve cushioning and wear resistance. Alternatively, the gripping toes themselves can be made of wear-resistant rubber.

[0058] The foot body 71 is generally shell-shaped, and its interior is equipped with longitudinally and transversely arranged support ribs 76 for reinforcement. The support ribs 76 are located directly above the gripping toe 73. This allows the force on the gripping toe 73 to be directly transmitted upwards, achieving good strength and load-bearing capacity.

[0059] The foot 71 of the supporting foot 7 is hemispherical, and the roller is placed side by side with the supporting foot 7 in the left-right direction. For example, the supporting foot is located on the left side, while the roller is located on the right side.

[0060] The roller can be a Mecanum roller, with its drive motor mounted on the hub.

[0061] When the rollers are in the retracted state (sleeper position, foot-supported state), their lower rims are level with, or roughly level with, the lowest point of the foot 71. However, they are slightly higher than the lowest point of the gripping toe. For example, the height difference is 5mm-10mm. Therefore, the rollers can provide some support on uneven or soft ground, improving the robot's maneuverability and reducing the likelihood of foreign objects entering the upper space through the central through-hole 72.

[0062] When the roller is in the extended position (wheel support position), its lower rim is lower than the lowest part of the foot body 71 and slightly lower than the lowest part of the gripping toe. For example, the height difference is 5mm-10mm. As a result, the roller moves a shorter distance up and down, the wheel-foot switching speed is faster, and the structure is more compact.

[0063] This invention also provides a robot, which includes the wheel-leg conversion device described above. The robot is a hexapod, and the wheel-leg conversion device is installed only on the left front, left rear, right front, and right rear legs. This simplifies the overall structure.

[0064] The embodiments of this utility model can ensure that the wheel-foot switching module has high stability and reliability during operation. Even under complex terrain and load conditions, it can ensure the accurate execution of switching actions and reduce the risk of robot failure or loss of control due to switching failure.

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it. Those skilled in the art should understand that modifications can be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. A wheel-foot conversion device, characterized in that, include: Robot lower leg, the robot lower leg is connected to the robot thigh, and a support foot (7) is fixedly provided at the lower end of the robot lower leg. The support foot (7) is used to contact the ground to support the robot. The roller screw unit includes a screw (2), a screw nut (3), and a screw motor (4). The two ends of the lead screw (2) are connected to the robot's lower legs. The lead screw motor (4) is connected to the lead screw (2) for driving the lead screw (2) to rotate in the forward and reverse directions, thereby driving the lead screw nut (3) to move in the forward or reverse direction along the lead screw (2). A roller is connected to the lead screw nut (3), and the roller moves along the axis of the lead screw (2) together with the lead screw nut (3) to realize the switching between wheel support and foot support.

2. The wheel-foot conversion device as described in claim 1, characterized in that, The wheel-foot conversion device includes two guide rods (5), which are set parallel to the lead screw (2) and are fixedly connected at both ends to the lower leg skeleton (1) of the robot's lower leg. A connecting plate (6) is fixedly connected to the lead screw nut (3), and the connecting plate (6) has a sliding hole that slides with the outer periphery of the guide rod (5).

3. The wheel-foot conversion device as described in claim 2, characterized in that, An electric gripper is installed on the connecting plate (6). The electric gripper has an open state and a clamping state. In the clamping state, the electric gripper holds the guide rod (5) tightly, preventing the connecting plate (6) from sliding relative to the guide rod (5). In the open state, the electric gripper releases the guide rod (5), allowing the connecting plate (6) to slide relative to the guide rod (5).

4. The wheel-foot conversion device as described in claim 3, characterized in that, When powered on, the electric gripper is in the open state; when de-powered, the electric gripper is in the clamping state.

5. The wheel-foot conversion device as described in claim 4, characterized in that, Two electric grippers are installed on the connecting plate (6), with one electric gripper corresponding to each guide rod (5).

6. The wheel-foot conversion device as described in any one of claims 1-5, characterized in that, The foot body (71) of the supporting foot (7) includes a semi-cylindrical part (75) and a quarter-spherical part (74) connected at the front and rear ends of the semi-cylindrical part (75); a central through hole (72) is provided at the middle position of the foot body to allow the roller to pass through.

7. The wheel-foot conversion device as described in claim 6, characterized in that, Two symmetrical gripping toes (73) are provided on the lower side of the semi-cylindrical part (75). The foot body (71) is integrally formed. The gripping toes (73) are installed on the foot body (71) in a replaceable manner, and the gripping part of the gripping toes (73) is hemispherical.

8. The wheel-foot conversion device as described in any one of claims 1-5, characterized in that, The foot body (71) of the supporting foot (7) is hemispherical, and the roller is placed side by side with the supporting foot (7) in the left-right direction.

9. The wheel-foot conversion device as described in any one of claims 1-5, characterized in that, The roller is a Mecanum roller, and its drive motor is mounted on the hub.

10. A robot, characterized in that, The robot is a hexapod robot, comprising the wheel-leg conversion device as described in any one of claims 1-9, wherein the wheel-leg conversion device is mounted only on the robot legs located on the left front, left rear, right front, and right rear.

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