A high-mobility crawler robot that does not change the radial dimension of the body during movement

Abstract

The application provides a high-mobility crawler robot which does not change the radial size of the body during movement, adopts a three-degree-of-freedom spherical branched-chain parallel mechanism for serial design, wherein all the connecting rods on the three branched chains are on the same space cylindrical surface during movement, the connecting rods keep the radial position of the cylindrical surface unchanged during movement, and only rotate or swing on the cylindrical surface, so that the movement branched chain of the robot does not expand radially during movement, thereby effectively improving the space utilization of the robot, enhancing the compactness and stability of the robot structure, and making the robot more easily miniaturized and moved in a narrow space. The application has longer movement branched chains under the condition of keeping the same outer diameter as the same kind of robots. This feature makes the robot have a larger working space, improves the applicability and flexibility of the robot in a complex operation environment, and the design of the long branched chain also enhances the operation range and flexibility of the robot.

Description

Technical Field

[0001] This invention relates to the field of crawling robot technology, specifically a highly mobile crawling robot that does not change its radial dimensions during movement. Background Technology

[0002] High-redundant-degree-of-freedom biomimetic robots, such as crawling robots and snake-like robots, are often used in confined environments, such as: detection inside slender pipes, inspection of engine air intakes and exhaust nozzles, nuclear power plant maintenance, and earthquake rescue. Existing crawling robots mostly use linear or pneumatic actuation for movement. These two types of robots have the following limitations: Linear actuation introduces elastic deformation due to the stretching and bending of the wire, affecting the robot's control accuracy. Furthermore, the wire often has low load-bearing capacity, making it unsuitable for tasks with heavy loads or high stress. Pneumatic robots require coordinated airflow and air supply to perform tasks, placing high demands on the working environment. Moreover, a single pneumatic cavity typically only allows for axial and radial extension and contraction, lacking pitch and yaw degrees of freedom. Pneumatic and linear actuation robots often only achieve one-dimensional or planar motion, lacking spatial movement capabilities and the ability to cope with obstacles and other complex environments.

[0003] The applicant previously proposed a highly mobile crawling robot that is easily miniaturized (patent number: CN115253545B). This robot employs a parallel linkage mechanism with straight links, enabling movements such as peristalsis, pitch, and yaw. Its motion chains are directly connected by straight links, and adjacent axes of rotation are perpendicular to each other. This design increases the range of motion of the mechanism, but also leads to an increase in the robot's outer diameter during retraction, such as... Figure 1 As shown. Therefore, the robot's operation is limited by the application environment above its radial dimension, restricting its mobility in certain confined space applications. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention proposes a highly mobile crawling robot that does not change its radial dimensions during movement. During movement, the structure does not expand radially outward, enhancing the robot's compactness and stability, and making it easier for the robot to move in narrow spaces.

[0005] The technical solution of this invention is as follows:

[0006] The highly mobile crawling robot that does not change its radial dimensions during movement includes a head structure, a tail structure, a torso structure, and a supporting leg structure. The torso structure is composed of multiple drive units connected in series, with adjacent drive units sharing a platform. The head structure is fixedly connected to the moving platform of the drive unit closest to the head, and the tail structure is fixedly connected to the base platform of the drive unit closest to the tail.

[0007] The drive unit is a 3-RRRRR parallel structure, comprising two platforms and three branches; the platform is divided into a base platform and a moving platform;

[0008] Its features are:

[0009] The platform has a Y-shaped structure with an O-shaped hole at its center. It comprises three support arms. At the ends of the three support arms, near the head, are drive motor mounting seats with motor output shaft holes at their centers. At the tail ends of the three support arms are pin holes for mounting the platform's support chains. The axes of the three motor output shaft holes intersect the normal line passing through the center point of the Y-shaped platform at a single point. The axes of the pin holes on the three pin holes also intersect the normal line passing through the center point of the Y-shaped platform at a single point. The projections of the pin hole axes on the three pin holes onto the Y-shaped platform intersect at the center point of the platform's O-shaped hole, with each pair of the three projected lines forming a 120° angle.

[0010] Each branch chain contains four links, which are connected by pins to form three sets of revolute joints. The planes of adjacent revolute joints are perpendicular to each other. The two links connected to the platform are spherical curved rods. The output shaft of the drive motor reducer passes through the shaft outlet hole of the mounting base and is fixed to the end of the first spherical link to form a revolute joint. The axis of the output shaft of the drive motor reducer is perpendicular to the axis of one end of the first spherical link. One end of the second spherical link is connected to the pin hole seat by a pin to form a set of revolute joints. The axis of the pin hole on the pin hole seat is perpendicular to the axis of one end of the second spherical link. The revolute joint formed by the output shaft of the motor reducer and the first spherical link fixed to it is a driven joint. The other four sets of revolute joints are driven revolute joints.

[0011] The three sets of drive pairs drive the spherical connecting rods fixed to them to rotate through the motor, and the remaining passive rotary pairs follow the movement, thereby changing the position of the moving platform relative to the base platform; and all the connecting rods on the three branches are on the same spatial cylindrical surface during the movement, and the connecting rods maintain the radial position of their cylindrical surface during the movement, and only rotate or swing on the cylindrical surface.

[0012] Furthermore, the three branches are the first branch, the second branch, and the third branch; the first branch connects the moving platform and the support arm of the base platform facing the ground, and the first branch faces upward; the second branch connects the moving platform and the support arm of the base platform facing upward, and the second branch faces downward; the third branch connects the moving platform and the support arm of the base platform facing the ground, and the third branch is close to the ground.

[0013] Furthermore, the connecting rods at both ends of the third branch include an arc section and a straight section. The central angle of curvature of the arc section is 45°, and the straight section is connected to the arc section to form a continuous structure. By changing part of the arc to a straight line, interference between the third branch and the ground is avoided.

[0014] Furthermore, the axis of the motor mounting base output shaft hole and the axis of the pin hole on the pin hole seat are respectively at an angle of α degrees with the axis of the platform center hole, and the angle α ranges from 45 degrees to 90 degrees.

[0015] Furthermore, the included angle α is 75 degrees.

[0016] Furthermore, the curvature center angle of each spherical rod is 45 degrees, the curvature center of the spherical rod is located at the center of the sphere, and it bends along a predetermined spherical path to form an arc with a central angle of 45°.

[0017] Furthermore, each drive unit has a support foot fixedly installed on the lower side of the platform near the tail. When all active pairs have equal angles, the bottom of all support feet are on the same plane, and the center points of the circular holes of all platforms are collinear.

[0018] Furthermore, the bottom of the supporting foot has a pre-reserved contact structure mounting groove to deploy a bristle-like structure, forming a motion "anchor point" to provide anisotropic friction force for the robot's movement.

[0019] Beneficial effects

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] 1. The robot of the present invention adopts a three-degree-of-freedom spherical branch parallel mechanism for series design. This design ensures that the motion branches will not expand radially outward during the robot's movement, thereby effectively improving the robot's space utilization, enhancing the robot's structural compactness and stability, and making the robot easier to miniaturize and move in narrow spaces.

[0022] 2. The robot of the present invention has a longer motion chain while maintaining the same outer diameter as similar robots. This feature allows the robot to have a larger workspace, improving its applicability and flexibility in complex operating environments. At the same time, the long chain design also enhances the robot's operating range and flexibility.

[0023] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0024] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0025] Figure 1 This is a schematic diagram of the changes in the inner and outer diameters of the torso during movement, as shown in patent CN115253545B.

[0026] Figure 2 This is a schematic diagram of a highly mobile crawling robot structure that does not change its radial dimensions during movement, according to the present invention.

[0027] Figure 3 This is a schematic diagram of the drive unit structure b2 and the supporting legs d2 and d3 of the robot of the present invention;

[0028] Figure 4 This is a schematic diagram of the segmental platform structure of the robot of the present invention;

[0029] Figure 5 This is a schematic diagram of the third branch link;

[0030] Figure 6 This is a diagram showing the extended posture of the segmental unit of the robot of the present invention;

[0031] Figure 7 This is a diagram showing the segmental unit contraction posture of the robot of the present invention;

[0032] Figure 8 This is a diagram showing the deflection posture of the segmental unit of the robot of the present invention;

[0033] Figure 9 This is a schematic diagram of the planar motion process of the robot of the present invention;

[0034] Figure 10 This is a motion posture diagram of a robot crossing a gap with width l and height difference h. Detailed Implementation

[0035] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0036] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," 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 limitations on this invention.

[0037] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0038] This embodiment describes a highly mobile crawling robot that does not change its radial dimensions during movement. See also... Figure 2 It includes a head structure a, a tail structure c, a torso structure b, and a supporting foot structure d. The torso structure is composed of multiple drive units connected in series, with two adjacent drive units sharing a platform. The head structure is fixedly connected to the moving platform of drive unit b1, and the tail structure is fixedly connected to the base platform of drive unit b4.

[0039] In this embodiment, the torso structure contains four drive units, namely drive unit b1, drive unit b2, drive unit b3, and drive unit b4. In other embodiments, the number of drive units and the allocation of sensor assembly positions can be reasonably increased or decreased according to the actual task requirements.

[0040] Taking drive unit b2 as an example, its detailed structure is explained below. See [link / reference] Figure 3 The drive unit is a 3-RRRRR parallel structure, which includes two platforms and three branches, of which 201 is the structural base platform and 221 is the moving platform.

[0041] by Figure 4Taking this example, the platform structure is described in detail. Each platform has a Y-shaped structure with an O-shaped hole in the center. The platform includes three support arms. At the ends of support arms 1, 2, and 3, near the head, are drive motor mounting seats 232, 233, and 234, respectively. Each mounting seat has a motor output shaft hole in the center, and near the tail, are pin hole seats 222, 223, and 224 for mounting the drive platform support chains. The axis of the motor mounting seat output shaft hole and the axis of the pin hole on the pin hole seat form an angle α with the axis of the platform's central hole. This angle α can range from 45 degrees to 90 degrees. In a preferred embodiment, the included angle α is 75 degrees, and the axes of the three motor output shaft holes intersect the normal line passing through the center point of the Y-shaped platform at a single point; the axes of the pin holes on the three pin hole seats intersect the normal line passing through the center point of the Y-shaped platform at a single point; the projections of the pin hole axes on the three pin hole seats onto the Y-shaped platform intersect at the center point of the platform O-shaped hole, and the three projected lines form a 120° angle between each pair; the projections of the axes of the three motor mounting seat output shaft holes onto the Y-shaped platform intersect at the center point of the platform O-shaped hole, and the three projected lines form a 120° angle between each pair.

[0042] It should be noted that the base platform has three motor mounting seats at the ends of its three support arms, and the moving platform has three pin holes at the ends of its three support arms. The three drive motors 202, 203, and 204 are respectively mounted on the support arm motor mounting seats of the base platform 201. All three branches are assembled between the two platforms, with 20a referred to as the first branch, 20b as the second branch, and 20c as the third branch. The first branch connects the moving platform to the support arm of the base platform facing the ground, and the first branch faces upward. The second branch connects the moving platform to the support arm of the base platform facing upward, and the second branch faces downward. The third branch connects the moving platform to the support arm of the base platform facing the ground on the other side, and the third branch is close to the ground.

[0043] Taking the first branch 20a as an example, this branch includes four links, namely links 211, 212, 213, and 214. Adjacent links are connected by pins, forming three sets of revolute joints. The planes of adjacent revolute joints are perpendicular to each other. Links 211 and 214 are spherical curved rods, each with a central angle of curvature of 45 degrees. Specifically, the center of curvature of links 211 and 214 is located at the center of the sphere, and they are bent along a predetermined spherical path to form an arc with a central angle of 45°. The output shaft of the drive motor 204 reducer passes through the shaft outlet hole of the mounting base and is fixedly connected to one end of link 211 to form a revolute joint. The output shaft axis is perpendicular to the axis of one end of connecting rod 211; one end of connecting rod 214 is connected to pin seat 222 by a pin, forming a set of revolute joints, wherein the axis of the pin hole on pin seat 222 is perpendicular to the axis of one end of connecting rod 214; the revolute joint formed by the output shaft of the motor reducer and the connecting rod fixed to it is called the driving joint, and the other four sets of revolute joints are all driven revolute joints; the three driving joints drive the connecting rods fixed to them to rotate through the motor, and the other driven revolute joints follow the movement, thereby changing the position of the moving platform relative to the base platform; it should be noted that, in order to avoid interference with the ground, connecting rods 216 and 217 in the third branch 20c are both U-shaped connecting rods, specifically, as Figure 5 As shown, each link includes an arc section and a straight section. The central angle of curvature of the arc section is 45°, and the straight section connects to the arc section to form a continuous structure. Simultaneously, the positions of the axes at both ends remain unchanged; that is, the geometric position of the link at the connection point does not change. Only a portion of the link's shape changes from a curve to a straight line. By changing part of the arc to a straight line, interference between the third branch and the ground is avoided. Through this design, all links on the three branches remain on the same spatial cylindrical surface during movement. That is, the trajectory of the link is confined within a fixed cylindrical surface during movement, thus preventing radial outward expansion. Specifically, the link maintains its radial position on the cylindrical surface during movement, only rotating or oscillating on the cylindrical surface.

[0044] See Figure 6 To facilitate understanding the motion of the drive unit, taking a robot segment unit as an example, a coordinate system is established at the center of the moving platform. Hereinafter, the forward and backward translation of the moving platform along the x-axis is called telescopic motion, rotation around the z-axis is called yaw motion, and rotation around the y-axis is called pitch motion. The attitude of the moving platform 221 relative to the base platform 201 is determined by the rotation angles of the active linkages 211, 217, and 218; specifically, the absolute magnitude of the rotation angles of the active linkages 211, 217, and 218 determines the translational distance between the moving platform and the base platform. Figure 6 This demonstrates the translational elongation motion of the mechanism along the x-axis when the rotation angles of links 211, 217, and 218 are the same. Figure 7This demonstrates the translational contraction motion of the mechanism along the x-axis when links 211, 217, and 218 rotate by the same angle. When links 217 and 218 rotate by the same angle, changing the difference in their rotation angles relative to link 211 alters the deflection angle of the moving platform relative to the base platform. Figure 8 The leftward deflection motion of the mechanism is demonstrated; when links 211 and 217 rotate by the same angle, changing the difference in rotation angle between them and link 218 can change the pitch angle of the moving platform relative to the base platform.

[0045] It should be noted that the robot's five pairs of supporting legs d1, d2, d3, d4, and d5 are installed sequentially on the lower side of the platform near the tail of the four drive units, and are fixed to the platform through the reserved mounting holes on the platform arms; when all active pairs have equal angles, the bottoms of the five pairs of supporting legs are all on the same plane, and the center points of the circular holes of all platforms are collinear.

[0046] Optionally, in some embodiments, the robot's bottom support feet d1, d2, d3, d4, and d5 are made using 3D printing; the bottom has reserved contact structure mounting slots to deploy a bristle-like structure, i.e., motion "anchor points," to provide anisotropic friction for the robot's movement.

[0047] The robot proposed in this patent can perform linear and yaw movements within a plane. See also Figure 9 This diagram illustrates two types of robot motion within a plane. Specifically, Figure 9 (a) Robot in the mid-elongation state Figure 6 The elongation motion of the drive unit, Figure 9 (a) The robot in the contracted elongation state Figure 7 The contraction motion of the drive unit, Figure 9 (a) Robot in the deflection state Figure 8 The deflection motion of the drive unit corresponds to the anchoring support foot, which plays an anchoring role in the robot's movement.

[0048] like Figure 9 (b) describes the robot's planar linear motion. It should be noted that the schematic diagram shown in the figure is the robot's top-down view. During the initial time t0, all the robot's drive units remain in an extended state. At time t1, the robot's head support foot is anchored to the ground, and all four drive units retract. At time t3, the robot's tail support foot is anchored to the ground, and all four drive units extend. The robot moves forward a straight distance d.

[0049] like Figure 9(c) illustrates the robot's planar deflection motion. It should be noted that the schematic diagram shown in the figure is a top-down view of the robot. During the initial time t0, all robot drive units remain extended. At time t1, drive unit b1 deflects to the left, while the other units remain unchanged. At time t2, drive unit b2 deflects to the left, and b1 returns to its previous state, while the other units remain unchanged. At time t3, drive unit b3 deflects to the left, and b2 returns to its previous state, while the other units remain unchanged. At time t4, drive unit b4 deflects to the left, and b3 returns to its previous state, while the other units remain unchanged. At time t5, drive unit b4 returns to its previous state, while the other units remain unchanged. Thus, the robot's overall deflection motion is completed.

[0050] The crawling robot of this invention can also combine the extension, deflection, and pitch movements of the drive unit to cross gaps and obstacles in space. Figure 10 This demonstrates a complex motion of a robot traversing an obstacle with a height difference of h and a width of l.

[0051] Optionally, in some embodiments, the bottom of the robot's support foot can be replaced with a negative pressure suction cup, an electrostatic adsorption device, or an electromagnet to enable adhesion to different material surfaces.

[0052] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention without departing from the principles and spirit of the present invention.

Claims

1. A high-mobility crawler robot in motion without changing the radial size of the body, comprising a head structure, a tail structure, a trunk structure and a support foot structure, the trunk structure being composed of a plurality of drive units connected in series, and a platform being shared by adjacent two drive units; the head structure being fixedly connected with the moving platform of the drive unit closest to the head, and the tail structure being fixedly connected with the base platform of the drive unit closest to the tail; the drive unit being a 3-RRRRR parallel structure, comprising two platforms and three branch chains; the platforms being divided into base platforms and moving platforms; characterized in that: the platform is a Y-shaped structure with an O-shaped hole in the center, the platform comprising three support arms, the ends of the three support arms on the side close to the head being respectively provided with a drive motor mounting seat, the center of the mounting seat being provided with a motor shaft hole, the ends of the three support arms on the side close to the tail being respectively provided with a pin hole seat for the installation of the moving platform branch chain; the axes of the three motor shaft holes intersecting with the normal line passing through the center point of the Y-shaped platform at a point, the axes of the pin holes on the three pin hole seats intersecting with the normal line passing through the center point of the Y-shaped platform at a point; the projections of the axes of the three pin hole seats on the Y-shaped platform intersecting at the center point of the O-shaped hole of the platform, the three projection straight lines being at an angle of 120° with each other; the projections of the axes of the three motor mounting seat shaft holes on the Y-shaped platform intersecting at the center point of the O-shaped hole of the platform, the three projection straight lines being at an angle of 120° with each other; each branch chain comprising four connecting rods connected by pins between adjacent connecting rods, forming three groups of rotary pairs, the planes of adjacent rotary pairs being perpendicular to each other, wherein the two connecting rods connected with the platform are spherical surface connecting rods, the output shaft of the drive motor reducer passing through the mounting seat shaft hole and being fixedly connected with the end of the first spherical surface connecting rod, forming a rotary pair, wherein the axis of the output shaft of the drive motor reducer is perpendicular to the axis of the end of the first spherical surface connecting rod; the end of the second spherical surface connecting rod being connected with the pin hole seat by a pin, forming a rotary pair, wherein the axis of the pin hole on the pin hole seat is perpendicular to the axis of the end of the second spherical surface connecting rod; the rotary pair formed by the motor reducer output shaft and the first spherical surface connecting rod fixedly connected therewith being a drive pair, and the remaining four rotary pairs being passive rotary pairs; the three groups of drive pairs generating rotation through the spherical surface connecting rods fixedly connected therewith driven by the motor, and the remaining passive rotary pairs following the movement, thereby changing the pose of the moving platform relative to the base platform; and all the connecting rods on the three branch chains being on the same spatial cylindrical surface during the movement, the connecting rods maintaining the radial position of the cylindrical surface unchanged during the movement, and only rotating or swinging on the cylindrical surface.

2. The high-mobility crawler robot that does not change the radial dimension of the body during movement according to claim 1, characterized by: The three branch chains are respectively a first branch chain, a second branch chain and a third branch chain; wherein the first branch chain connects the side arms of the moving platform and the base platform facing the ground, and the first branch chain faces upward, the second branch chain connects the side arms of the moving platform and the base platform facing upward, and the second branch chain faces downward, and the third branch chain connects the other side arms of the moving platform and the base platform facing the ground, and the third branch chain is close to the ground.

3. The high-mobility crawler robot of claim 2, wherein: The connecting rods at both ends of the third branch chain comprise a circular arc portion and a straight line portion, the central angle of the curvature of the circular arc portion being 45°, and the straight line portion being connected with the circular arc portion to form a continuous structure, and the interference between the third branch chain and the ground being avoided by changing part of the circular arc to a straight line.

4. The high-mobility crawler robot of claim 1, wherein: The motor mounting seat exit shaft hole axis and the pin hole axis of the pin hole seat are respectively at an angle α with the platform center hole axis, and the angle α ranges from 45 degrees to 90 degrees.

5. The high-mobility crawler robot of claim 4, wherein: The angle α is 75 degrees.

6. The high-mobility crawler robot that does not change the radial dimension of the body during movement according to claim 1, characterized by: Each spherical curved rod has a curvature circle central angle of 45 degrees, the curvature circle center of the spherical curved rod is located at the center of the sphere, and the spherical curved rod is curved along a predetermined spherical path to form an arc with a central angle of 45 degrees.

7. The high-mobility crawler robot of claim 1, wherein: The platform of each driving unit is fixedly installed with a support foot below a side near the tail, and when all driving sub-angles are equal, the bottoms of all support feet are on the same plane, and the center points of the circular holes of all platforms are collinear.

8. The high-mobility crawler robot of claim 7, wherein: The bottom of the support foot is reserved with a contact structure installation slot to deploy a structure similar to a bristle to form a motion "anchor point" and provide forward and backward anisotropic friction for the motion of the robot.

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