A ball-wheel combined multi-modal mobile robot with branched foot arms

Abstract

A kind of ball wheel composite multimodal mobile robot with branch foot arm belongs to the field of robot technology.The existing patrol robot has the problems of poor terrain adaptability, poor passability, poor climbing ability and poor flexibility. The outer wheel hub is supported on the ground;The inner drive steering mechanism is assembled in the outer wheel hub, which is used to realize the driving and steering control of the robot in wheel mode and ball mode;The ball wheel switching mechanism includes two folding and unfolding modules symmetrically arranged on the left and right sides of the outer wheel hub, each folding and unfolding module can perform unfolding or folding action;When the robot is in wheel mode, two folding and unfolding modules perform unfolding action, respectively forming hemispherical structure on both sides of the outer wheel hub, and forming spherical structure as a whole, so that the robot is switched from wheel mode to ball mode;When two folding and unfolding modules perform folding action, they are fitted and stored on both sides of the outer wheel hub, and the outer wheel hub independently contacts and supports on the ground, and the robot is switched from ball mode to wheel mode.

Description

Technical Field

[0001] This invention relates to the field of robotics, and more particularly to a ball-wheel composite multimodal mobile robot with branched legs and arms. Background Technology

[0002] With the ever-increasing demand for extraterrestrial exploration, scientific investigations of celestial bodies such as the Moon, Mars, and asteroids are gradually expanding into deeper and more complex regions. The surfaces of extraterrestrial bodies generally contain numerous and varied deep craters and unstructured terrains. These areas often preserve important geological information about the evolution of celestial bodies and have extremely high scientific research value. However, facing these extreme terrains, how to achieve efficient and reliable access and exploration has become a key challenge that urgently needs to be solved in the current aerospace field.

[0003] Most existing traditional lunar rovers employ multi-wheeled or tracked locomotion. While this design offers good operational stability on relatively flat surfaces, it presents significant limitations when navigating complex terrains and areas with deep craters. On craters, rock formations, steep slopes, or other irregular surfaces, traditional rovers lack sufficient mobility, climbing ability, and maneuverability, making it difficult to perform exploration missions in narrow or deep geographical environments. Therefore, there is an urgent need to develop a lightweight exploration robot technology with high terrain adaptability, strong obstacle-crossing ability, and high mobility to meet the exploration requirements of complex lunar surface terrain. Summary of the Invention

[0004] In view of this, the present invention provides a ball-wheel composite multimodal mobile robot with branched legs and arms, which can be in ball mode or wheel mode to meet the exploration needs of complex planetary terrain.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0006] A ball-wheel hybrid multimodal mobile robot with branched legs and arms includes:

[0007] The outer hub has a rim that can be supported on the ground.

[0008] An internal drive steering mechanism, installed inside the outer wheel hub, is used to realize the robot's propulsion drive and steering control in ball mode;

[0009] The ball wheel switching mechanism includes two folding modules symmetrically arranged on the left and right sides of the outer wheel hub, each of which can perform an unfolding or retracting action;

[0010] When the robot is in wheel mode, the two folding modules unfold, forming hemispherical structures on both sides of the outer wheel hub, and the whole structure forms a spherical structure, thus switching the robot from wheel mode to spherical mode. When the two folding modules retract, they fit snugly against both sides of the outer wheel hub, and the outer wheel hub independently contacts and supports the ground, thus switching the robot from spherical mode to wheel mode.

[0011] Furthermore, the internal drive steering mechanism includes an internal gear ring, a steering drive module, and a travel drive module. The internal gear ring is coaxially disposed inside the outer hub and rotatably connected to the outer hub. The steering drive module is connected to the internal gear ring and can drive the internal gear ring to rotate relative to the outer hub to achieve steering adjustment in the robot's ball mode. The travel drive module can drive the internal gear ring to rotate around its own axis so that the internal gear ring can drive the robot to complete forward or backward movements.

[0012] Furthermore, the steering drive module includes a steering motor, a worm gear, and a worm. The steering motor is fixed to the inner ring wall of the outer hub and can drive the worm to rotate. The worm gear is connected to the internal gear ring and meshes with the worm.

[0013] Furthermore, the travel drive module includes a travel motor, a driven spur gear, and a clamping and positioning bracket. The clamping and positioning bracket is clamped on the left and right sides of the internal gear ring and forms a sliding fit with the internal gear ring. The travel motor is fixed to the clamping and positioning bracket and can drive the driven spur gear to rotate. The driven spur gear meshes with the internal gear ring to drive the internal gear ring to rotate around its own axis.

[0014] Furthermore, the internal drive steering mechanism also includes two branch legs symmetrically mounted on the left and right sides of the travel drive module. Each branch leg can perform up-and-down flipping motions. When the two branch legs are flipped down to support the ground, the robot can be kept upright. When the two branch legs are flipped up, the robot's center of gravity can be adjusted by the left and right swaying of the two branch legs, so as to realize the steering adjustment in the robot's wheel mode.

[0015] Furthermore, each folding module includes an unfolding / retracting drive unit and a cross linkage unit. Multiple unfolding / retracting drive units are provided and are evenly distributed along the circumference of the outer hub. Each unfolding / retracting drive unit corresponds to a cross linkage unit and can drive the corresponding cross linkage unit to perform unfolding or retracting actions to complete the switching between the robot's ball mode and wheel mode.

[0016] Furthermore, each cross linkage unit includes an arc-shaped first link, second link, and third link. Two of each of the first, second, and third links are provided and divided into two groups. The first, second, and third links in each group are hinged end to end. The first ends of the first links in both groups are connected to the extension and retraction drive unit and can swing laterally relative to each other under the drive of the extension and retraction drive unit. The second links in the two groups are arranged crosswise and hinged. The ends of the third links in the two groups are hinged, forming two parallelogram linkage mechanisms arranged in series.

[0017] Furthermore, each deployment and retraction drive unit includes a deployment and retraction motor, a second driving wheel, a second driven wheel, a rotating shaft, a gearbox, and two sets of transmission gear pairs. The deployment and retraction motor and the rotating shaft are both fixedly mounted on the outer hub. The deployment and retraction motor can drive the second driving wheel to rotate. The second driven wheel is fixedly connected to the gearbox, and both are sleeved on the rotating shaft. The second driving wheel and the second driven wheel mesh with each other. The two sets of transmission gear pairs are arranged in opposite directions and side by side inside the gearbox, and correspond one-to-one with the two first connecting rods. Each set of transmission gear pairs can transmit the rotational motion of the gearbox to the corresponding first connecting rod to drive the two first connecting rods to perform opposite lateral swing motion.

[0018] Furthermore, each transmission gear pair includes a first bevel gear, a second bevel gear, a first spur gear, and a second spur gear; the first bevel gear is mounted on a rotating shaft and remains fixed, the second bevel gear is rotatably mounted on a gearbox and meshes with the first bevel gear, the first spur gear is connected to the second bevel gear and can rotate with the second bevel gear, and the second spur gear is connected to the corresponding first connecting rod and meshes with the first spur gear.

[0019] Furthermore, each folding and unfolding module also includes multiple linkage transmission units. Two adjacent unfolding and unfolding drive units are connected by a linkage transmission unit. Only one unfolding and unfolding drive unit is an active drive structure, while the other unfolding and unfolding drive units have the unfolding and unfolding motor, the second drive wheel, and the second driven wheel removed.

[0020] The beneficial effects of this invention compared to the prior art are:

[0021] 1. The internal drive steering mechanism of this invention consists of an internal gear ring, a steering drive module, a travel drive module, and branch legs. Through the cooperation of the travel drive module and the internal gear ring, the robot can perform forward and backward movements in both wheeled and ball-like modes. The cooperation of the steering drive module and the internal gear ring allows for control of the robot's direction of travel in ball-like mode; the branch legs adjust the robot's center of gravity, enabling steering control in wheeled mode. Simultaneously, the branch legs can fold down to support the ground when the robot is stationary, keeping the robot upright.

[0022] 2. The driving mechanism of the travel drive module and the internal gear ring of the present invention adopts the "hamster ball motion" principle. This design allows the robot's overall center of gravity to be lower and its position to remain stationary. It can maintain stability during travel, turning and attitude switching, thereby improving the robot's smoothness and anti-tipping ability.

[0023] 3. The deployment and retraction drive unit of this invention abandons the traditional gearbox arrangement and adopts a structural design with a fixed rotating shaft and a gearbox rotating around the rotating shaft. Combined with the meshing transmission of the transmission gear pair, it can drive the two first connecting rods to complete the lateral swinging motion in opposite directions, realizing the retraction and deployment of the cross linkage unit. On the other hand, it can also drive the entire cross linkage unit to flip up and down through the first connecting rods. When the robot switches to wheel mode, the cross linkage unit can be retracted and attached to the side wall of the outer wheel hub, avoiding contact friction between the connecting rods and the ground, eliminating the hidden danger of connecting rod collision and deformation, which not only improves the working stability of the cross linkage unit, but also further extends its service life.

[0024] 4. The deployment and retraction module of this invention relies on the linkage transmission characteristics of the linkage transmission unit to achieve synchronous movement of all cross linkage units under the drive of a single motor. While reducing motor configuration and simplifying the structure, it also reduces the energy consumption of the whole machine and extends the continuous operation time of the robot. Attached Figure Description

[0025] The accompanying drawings, which form part of this invention, are provided to give a further understanding of the invention.

[0026] Figure 1 This is a schematic diagram of the robot in its wheeled mode supported on the ground according to the present invention.

[0027] Figure 2 This is a front view of the robot in wheeled mode of the present invention when it is supported on the ground.

[0028] Figure 3 This is a schematic diagram of the robot in motion mode according to the present invention.

[0029] Figure 4 This is a front view of the robot in its wheeled mode, in motion, according to the present invention.

[0030] Figure 5 This is a schematic diagram of the robot in the spherical mode of the present invention when it is supported on the ground.

[0031] Figure 6 This is a front view of the robot in the spherical mode of the present invention when it is supported on the ground.

[0032] Figure 7 This is a side view of the robot in the spherical mode of the present invention when it is supported on the ground.

[0033] Figure 8 This is a schematic diagram of the robot in motion in the spherical mode of the present invention.

[0034] Figure 9 This is a cross-sectional schematic diagram of the robot in motion in the spherical mode of the present invention.

[0035] Figure 10 for Figure 5 A magnified view of a portion of point A in the middle.

[0036] Figure 11 for Figure 9 A magnified view of a section at point C.

[0037] Figure 12 for Figure 5 A magnified view of a section at point B.

[0038] Figure 13 This is a cross-sectional schematic diagram of the deployment and retraction drive unit.

[0039] Explanation of reference numerals in the attached figures:

[0040] 1. Internal gear ring; 11. Vertical clamping surface; 12. Oblique clamping surface; 13. First rotating shaft; 2. Steering drive module; 21. Steering motor; 22. First driving wheel; 23. First driven wheel; 24. Worm gear; 25. Worm; 3. Travel drive module; 31. Travel motor; 32. Driving bevel gear; 33. Driven bevel gear; 34. Driven spur gear; 35. Support shaft; 36. Clamping positioning bracket; 361. U-shaped bracket; 362. Guide positioning wheel; 363. Bending support plate; 4. Branch arm; 41. First joint servo motor; 42. Second joint servo motor; 43. Third joint servo motor; 44. Support seat; 45. Counterweight; 46. First joint connection 47. Second joint connecting seat; 48. Support leg; 5. Extension and retraction drive unit; 51. Support link; 52. Second driving wheel; 53. Second driven wheel; 54. Rotating shaft; 55. Gearbox; 56. Transmission gear pair; 561. First bevel gear; 562. Second bevel gear; 563. Second rotating shaft; 564. First spur gear; 565. Second spur gear; 6. Cross linkage unit; 61. First link; 62. Second link; 63. Third link; 7. Linkage transmission unit; 71. First transmission link; 72. Second transmission link; 73. Third transmission link; 100. Outer hub; 200. Internal drive steering mechanism; 300. Ball wheel switching mechanism. Detailed Implementation

[0041] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0042] See Figures 1 to 8The structure shown in this embodiment discloses a ball-wheel composite multimodal mobile robot with branched legs and arms, primarily suitable for exploration operations in complex terrains of deep-space celestial bodies such as the Moon, Mars, and asteroids. The robot mainly consists of an outer hub 100, an internal drive steering mechanism 200, and a ball-wheel switching mechanism 300. The rim of the outer hub 100 is supported by the ground and also serves as a load-bearing base for mounting and supporting the internal drive steering mechanism 200 and the ball-wheel switching mechanism 300. The outer hub 100 uses screen wheels, which reduces the overall weight of the robot. Figure 1 , Figure 3 and Figure 5 The structure shown has an internal drive steering mechanism 200 mounted inside the outer hub 100, used to realize the robot's movement drive and steering control in wheeled and ball-like modes. Figure 2 , Figure 4 and Figure 6 As shown, the ball-wheel switching mechanism 300 includes two unfolding modules symmetrically arranged on the left and right sides of the outer hub 100. Each module can unfold or retract. When the robot is in wheel mode, the two unfolding modules unfold, forming hemispherical structures on both sides of the outer hub 100. These two hemispherical structures combine with the outer hub 100 to form a complete spherical structure, allowing the robot to switch from wheel mode to spherical mode. When the two unfolding modules retract, they fit snugly against the sides of the outer hub 100, which independently contacts and supports the ground, allowing the robot to switch back from spherical mode to wheel mode.

[0043] In this embodiment, the ball-wheel switching mechanism 300 relies on the folding motion of two folding modules to quickly switch between the robot's ball mode and wheel mode; at the same time, in conjunction with the control of the internal drive steering mechanism 200, it can realize the robot's movement and turning functions in different modes.

[0044] To achieve propulsion and steering control of the robot in both wheeled and ball-like modes, combined with Figure 1 , Figure 3 , Figure 5 and Figure 8 As shown in the diagram, the internal drive steering mechanism 200 of this embodiment mainly consists of an internal gear ring 1, a steering drive module 2, and a travel drive module 3. The internal gear ring 1 is coaxially disposed inside the outer hub 100, forming an annular mounting channel between them. The upper and lower ends of the internal gear ring 1 are respectively provided with first rotating shafts 13, and these two first rotating shafts 13 form a rotational engagement with the outer hub 100, meaning the internal gear ring 1 can rotate relative to the outer hub 100 to obtain a steering deflection angle. Combined with... Figure 5 and Figure 10The steering drive module 2 is arranged in the annular mounting channel between the outer hub 100 and the inner gear ring 1, and is connected to one of the first rotating shafts 13. It is used to drive the inner gear ring 1 to rotate around the line connecting the two first rotating shafts 13, so as to realize the steering adjustment in the robot's ball mode. The travel drive module 3 is connected to the inner gear ring 1 and can drive the inner gear ring 1 to rotate around its own axis, thereby driving the robot to complete forward or backward movements through the inner gear ring 1.

[0045] When the robot is in wheeled mode, the steering drive module 2 keeps the internal gear ring 1 and the outer hub 100 coaxial. The travel drive module 3 inputs driving force to the internal gear ring 1, which transmits the driving force along the rim direction of the outer hub 100, causing the outer hub 100 to rotate around its own axis, thus enabling the robot to move forward and backward in wheeled mode. When the robot switches to spherical mode, the steering drive module 2 drives the internal gear ring 1 to deflect around the line connecting the two first rotating shafts 13 according to the preset travel direction, adjusting the attitude angle of the internal gear ring 1 within the robot in spherical mode so that the outer ring surface of the internal gear ring 1 faces the travel direction, thereby completing the adjustment of the travel direction. The travel drive module 3 drives the internal gear ring 1 to rotate around its own axis, and through the transmission of the internal gear ring 1, the robot moves forward or backward in the preset direction in spherical mode.

[0046] Obviously, in this embodiment, the robot's direction of travel is controlled by the cooperation of the steering drive module 2 and the internal gear ring 1; and the robot's forward and backward movement is ensured by the cooperation of the travel drive module 3 and the internal gear ring 1 in both wheel mode and ball mode.

[0047] Among them, combined Figure 5 and Figure 10 As shown in the diagram, the steering drive module 2 in this embodiment includes a steering motor 21, a first driving wheel 22, a first driven wheel 23, a worm gear 24, and a worm 25. The housing of the steering motor 21 is fixedly mounted on the outer hub 100, and its motor shaft is fixedly connected to the first driving wheel 22, which can drive the first driving wheel 22 to rotate. The worm gear 25 is rotatably mounted on the outer hub 100, and the first driven wheel 23 is coaxially sleeved on the worm gear 25 and meshes with the first driving wheel 22. The worm gear 24 is sleeved on one of the first rotating shafts 13 and meshes with the worm gear 25.

[0048] When the steering motor 21 drives the first drive wheel 22 to rotate, the first drive wheel 22 drives the worm 25 to rotate through the first driven wheel 23. The worm 25 further drives the worm wheel 24 to rotate, and finally drives the internal gear ring 1 to rotate through the first rotating shaft 13.

[0049] Combination Figure 5 and Figure 11As shown in the diagram, the driving module 3 in this embodiment includes a driving motor 31, a driving bevel gear 32, a driven bevel gear 33, a driven spur gear 34, a support shaft 35, and a clamping and positioning bracket 36. The clamping and positioning bracket 36 clamps the left and right sides of the internal gear ring 1 and forms a sliding fit with the internal gear ring 1. Specifically, the clamping and positioning bracket 36 includes an inverted U-shaped bracket 361, a pair of bent support plates 363, and eight guide positioning wheels 362; the pair of bent support plates 363 are symmetrically arranged on the left and right sides of the internal gear ring 1 and are fixedly installed at the bottom opening of the U-shaped bracket 361; each bent support plate 363 has two guide positioning wheels 362 arranged side by side on its transverse support section and oblique support section. The left and right sides of the internal gear ring 1 are respectively provided with vertical clamping surfaces 11 and oblique clamping surfaces 12. The guide positioning wheels 362 on the horizontal support sections of the two bent support plates 363 contact and press the vertical clamping surfaces 11 on the left and right sides of the internal gear ring 1. The guide positioning wheels 362 on the oblique support sections of the two bent support plates 363 contact and press the oblique clamping surfaces 12 on the left and right sides of the internal gear ring 1. In this way, the clamping positioning bracket 36 and the internal gear ring 1 are clamped and positioned, ensuring that the clamping positioning bracket 36 will not separate from the internal gear ring 1 during the rotation of the internal gear ring 1. The motor housing of the travel motor 31 is fixed to the top of the U-shaped bracket 361, and its motor shaft extends into the U-shaped bracket 361 and is connected to the driving bevel gear 32, which can drive the driving bevel gear 32 to rotate. The driven bevel gear 33 and the driven spur gear 34 are coaxially mounted on the support shaft 35 and are rotatably installed inside the U-shaped bracket 361 through the support shaft 35. The driven bevel gear 33 and the driving bevel gear 32 mesh with each other, and the driven spur gear 34 forms a meshing transmission connection with the internal gear ring 1.

[0050] When the travel motor 31 drives the driving bevel gear 32 to rotate, the driving bevel gear 32 drives the driven spur gear 34 to rotate synchronously through the driven bevel gear 33. The driven spur gear 34 applies a driving force to the internal gear ring 1. Since the outer hub 100 is in contact with the ground, when the output torque of the travel motor 31 is less than the static friction force of the ground on the outer hub 100, the outer hub 100 and the internal gear ring 1 remain stationary under the action of this static friction force. At this time, the driving force of the driven spur gear 34 on the internal gear ring 1 acts in the opposite direction to the driven spur gear 34. The driven spur gear 34 drives the clamping and positioning bracket 36 to move along the tooth extension direction of the internal gear ring 1 through the driven bevel gear 33 and the driving bevel gear 32. When the output torque of the travel motor 31 is greater than the maximum static friction force of the ground on the outer hub 100, the clamping and positioning bracket 36 remains stationary relative to the internal gear ring 1. The driven spur gear 34 drives the internal gear ring 1 to rotate, and the internal gear ring 1 then drives the outer hub 100 to move forward or backward.

[0051] In this embodiment, the driving mechanism of the travel drive module 3 and the internal gear ring 1 adopts the "hamster ball motion" principle. The travel drive module 3 can be regarded as a hamster, and the spherical structure formed by the internal gear ring 1, the outer hub 100, and the unfolded ball wheel switching mechanism 300 can be regarded as a spherical motion device. When the hamster runs in the spherical motion device, in the initial acceleration phase, the hamster runs upward along the inner wall of the sphere. When the running speed reaches a certain threshold, the sphere and the hamster reach the same speed, and the hamster will eventually return to the bottom of the sphere due to gravity. This embodiment adopts the hamster ball motion design, which can make the robot's overall center of gravity lower and its position remain stationary. It can maintain stability during travel, turning, and posture switching, improving the robot's motion smoothness and anti-tipping ability.

[0052] Furthermore, combined Figures 1 to 5 As shown in the diagram, to enable the robot to turn in wheeled mode, the internal drive steering mechanism 200 of this embodiment is also equipped with two branch legs 4. These two branch legs 4 are symmetrically installed on both sides of the driving module 3 and can perform up-and-down flipping movements. They are mainly used to support the robot to maintain an upright position or to adjust the robot's center of gravity to enable the robot to turn in wheeled mode.

[0053] Combination Figure 3 As shown in the structure, each branch arm 4 in this embodiment includes a joint servo, a support base 44, a counterweight 45, a joint connector, and a support leg 48. Three joint servos are arranged sequentially along the length of the branch arm 4, designated as a first joint servo 41, a second joint servo 42, and a third joint servo 43. Two joint connectors are provided to connect adjacent joint servos for power transmission; these two connectors are designated as a first joint connector 46 and a second joint connector 47. The first joint connector 46 consists of two mutually perpendicular U-shaped connectors to increase the degrees of freedom of the branch arm 4, while the second joint connector 47 is an independent U-shaped connector. The support base 44 is fixedly installed on the outer wall of the U-shaped bracket 361, and the counterweight 45 is assembled inside the support base 44 to increase the weight of the travel drive module 3, thereby lowering the robot's overall center of gravity and improving operational stability. The housing of the first joint servo motor 41 is fixedly connected to the support base 44, and the servo disk is connected to one of the U-shaped connecting seats of the first joint connecting seat 46, which can drive the first joint connecting seat 46 to rotate around the X-axis; the housing of the second joint servo motor 42 is connected to the second joint connecting seat 47, and the servo disk is connected to the other U-shaped connecting seat of the first joint connecting seat 46, which can drive the second joint connecting seat 47 to rotate around the Y-axis; the housing of the third joint servo motor 43 is connected to the support leg 48, and the servo disk is connected to the second joint connecting seat 47, which can drive the support leg 48 to rotate around the Y-axis.

[0054] When the first joint servo motor 41 drives the first joint connecting seat 46 to rotate around the X-axis, the first joint connecting seat 46 can simultaneously drive the second joint servo motor 42, the second joint connecting seat 47, the third joint servo motor 43, and the support leg 48 to swing forward or backward; when the second joint servo motor 42 drives the second joint connecting seat 47 to rotate around the Y-axis, the second joint connecting seat 47 can drive the third joint servo motor 43 and the support leg 48 to flip up and down; when the third joint servo motor 43 drives the support leg 48 to rotate around the Y-axis, the support leg 48 can complete the up and down flipping action.

[0055] When the robot is in an upright, stationary state, the three joint servo motors work together to rotate the supporting legs 48 of both left and right branch arms 4 downwards and support them on the ground, ensuring the robot's stable standing. When the robot switches to wheeled mode, the three joint servo motors work together to rotate the supporting legs 48 upwards and retract them, preventing them from interfering with the ground. This also maintains the symmetrical arrangement of the left and right branch arms 4, ensuring the overall structure of the robot is symmetrical and guaranteeing smooth and reliable movement. If turning is required in wheeled mode, the supporting legs 48 can be rotated to different degrees by controlling the joint servo motors on both sides, resulting in an asymmetrical arrangement of the branch arms 4. This adjusts the overall center of gravity and achieves steering control. Furthermore, when the robot is traveling on soft ground and sinks, the support of the two branch arms 4 can be used to lift the robot and free it from the obstacle. Therefore, the branch arms 4 in this embodiment have multiple functions, improving the robot's integration and adaptability to different working conditions.

[0056] See Figure 5 The unfolding module of this embodiment includes an unfolding drive unit 5 and a cross linkage unit 6. There are multiple unfolding drive units 5, which are evenly arranged along the circumference of the outer hub 100. Each unfolding drive unit 5 corresponds to a cross linkage unit 6 and can drive the corresponding cross linkage unit 6 to perform unfolding or retracting actions to complete the switching between the robot's ball mode and wheel mode.

[0057] Specifically, each cross linkage unit 6 includes an arc-shaped first link 61, a second link 62, and a third link 63. Two of each of the first, second, and third links 63 are arranged in two groups. Within each group, the first, second, and third links 63 are sequentially hinged end-to-end. In both groups, the first end of the first link 61 is connected to the extension / retraction drive unit 5, enabling lateral swinging under its drive. The second links 62 in the two groups are arranged crosswise and rotatably connected by pins. The ends of the third links 63 in the two groups are rotatably connected by pins, thus forming two parallelogram linkage mechanisms arranged in series and coupled together.

[0058] When the ends of the two first links 61 swing inward synchronously under the drive of the extension and retraction drive unit 5, the two parallelogram linkages connected in series deform in unison and unfold as a whole. That is, the first link 61 pushes the second link 62 to move away from the outer hub 100, and the second link 62 simultaneously pushes the third link 63 to move away from the outer hub 100. The individual cross linkage unit 6 gradually unfolds. Since the first link 61, the second link 62, and the third link 63 all adopt an arc-shaped structure, the ends of all cross linkage units 6 gradually converge towards the central axis of the outer hub 100, eventually forming a hemispherical structure. The robot completes the form switch from wheel mode to spherical mode. Conversely, when the ends of the two first links 61 swing outward synchronously under the drive of the extension and retraction drive unit 5, the two parallelogram linkages connected in series deform in the opposite direction and move together as a whole. That is, the first link 61 pulls the second link 62 to retract towards the outer hub 100, and the second link 62 simultaneously pulls the third link 63 to retract towards the outer hub 100. Each cross link unit 6 gradually retracts and abuts against the side wall of the outer hub 100, and the robot completes the form switch from ball mode to wheel mode.

[0059] It should be noted that, since the ball wheel switching mechanism 300 in this embodiment adopts a linkage structure to achieve deformation, it has good scalability. By adjusting the length and number of linkages and increasing the number of parallelogram linkage mechanisms, more unfolding and retracting units can be constructed, thereby increasing the envelope surface area in the spherical state and reducing the structural gaps when unfolding.

[0060] Because when the cross linkage unit 6 retracts to the side of the outer hub 100, the retracted surface of the linkage is nearly flush with the rim surface of the outer hub 100. During the robot's wheeled movement, the linkage is prone to friction and collision with the ground, which can easily cause plastic deformation of the linkage, thus affecting the reliability and motion accuracy of the subsequent deployment action of the linkage. Therefore, in this embodiment, the deployment and retraction drive unit 5 can drive the cross linkage unit 6 to retract to the side of the outer hub 100, and at the same time drive the cross linkage unit 6 to rotate as a whole towards the outer hub 100, so that the retracted surface of the linkage is attached to the side wall of the outer hub 100 (e.g., Figure 1 and Figure 3 (as shown in the diagram) it is disconnected from the ground to avoid friction and collision damage, and to extend the service life of the cross linkage unit 6.

[0061] Specifically, combined Figure 12 , Figure 13As shown in the diagram, the deployment and retraction drive unit 5 of this embodiment includes a deployment and retraction motor (not shown), a support link 51, a second driving wheel 52, a second driven wheel 53, a rotating shaft 54, a gearbox 55, and two sets of transmission gear pairs 56. The deployment and retraction motor is fixed to the outer hub 100 via the support link 51. The second driving wheel 52 is coaxially connected to the output shaft of the deployment and retraction motor and can rotate synchronously with it. The rotating shaft 54 ​​is also fixedly installed to the outer hub 100 via the support link 51. The gearbox 55 and the second driven wheel 53 are both loosely fitted around the rotating shaft 54 ​​and can rotate around the rotating shaft 54. The second driven wheel 53 is fixedly connected to the gearbox 55 and meshes with the second driving wheel 52 to form a transmission pair. The two sets of transmission gear pairs 56 are arranged side by side inside the gearbox 55 and form a cross correspondence with the two first links 61 on the left and right sides, that is, the left transmission gear pair 56 matches the right first link 61, and the right transmission gear pair 56 matches the left first link 61. Each set of transmission gear pairs 56 can realize the power transmission between the gearbox 55 and the corresponding first connecting rod 61, driving the first connecting rod 61 to rotate; the two sets of transmission gear pairs 56 are arranged in opposite directions, so that the two first connecting rods 61 are subjected to driving forces in opposite directions, thereby realizing reverse movement.

[0062] Specifically, each set of transmission gear pairs 56 includes a first bevel gear 561, a second bevel gear 562, a second rotating shaft 563, a first spur gear 564, and a second spur gear 565. The first bevel gear 561 is mounted on the rotating shaft 54 ​​and remains fixed. The second bevel gear 562 is rotatably mounted on the gearbox 55 via the second rotating shaft 563 and meshes with the first bevel gear 561 to form a set of bevel gear pairs. The two sets of bevel gear pairs in the two sets of transmission gear pairs 56 are arranged symmetrically from left to right to output driving torques in opposite directions. The first spur gear 564 is fixedly mounted on the second rotating shaft 563 and rotates synchronously with the second rotating shaft 563. Each first connecting rod 61 has a drive shaft at its head end that extends into the gearbox 55. The second spur gear 565 is fixedly connected to the drive shaft of the corresponding first connecting rod 61 and meshes with the first spur gear 564. Since the left-side transmission gear pair 56 corresponds to the right-side first connecting rod 61, and the right-side transmission gear pair 56 corresponds to the left-side first connecting rod 61, to avoid assembly interference between the two sets of transmission gear pairs 56, such as... Figure 13 As shown, the drive shaft of the first connecting rod 61 on the right is a bushing structure, and the drive shaft of the first connecting rod 61 on the left is coaxially inserted inside the bushing, and the two can rotate relative to each other.

[0063] During the transition from wheeled to spherical mode, the branch arm 4 supports the ground, and the extension and retraction motor drives the second drive wheel 52 to rotate clockwise. The second drive wheel 52 drives the second driven wheel 53 to rotate counterclockwise through meshing transmission, thereby causing the gearbox 55 to rotate counterclockwise around the rotating shaft 54. During the rotation of the gearbox 55, the second bevel gears 562 of the two sets of transmission gear pairs 56 rotate counterclockwise around the rotating shaft 54. Because the bevel gear pairs in the two sets of transmission gear pairs 56 are symmetrically arranged, when the first bevel gear 561 remains stationary, the two second bevel gears 562 will be driven by opposite directions. Among them, the second bevel gear 562 on the left side rotates counterclockwise while being driven by the first bevel gear 561 on the left side to rotate counterclockwise, and drives the second rotating shaft 563 to rotate counterclockwise. The second shaft 563, through the meshing of the first spur gear 564 and the second spur gear 565, drives the transmission shaft corresponding to the first link 61 to rotate clockwise, thereby causing the first link 61 on the right to swing to the left. Simultaneously, the second bevel gear 562 on the right, while revolving counterclockwise, is driven by the first bevel gear 561 on the right to rotate clockwise, thus causing the second shaft 563 to rotate clockwise. The second shaft 563, through the meshing of the first spur gear 564 and the second spur gear 565, drives the transmission shaft corresponding to the first link 61 to rotate counterclockwise, thereby causing the first link 61 on the left to swing to the right. At this time, the cross linkage unit 6 performs an unfolding movement and extends towards the central axis of the outer hub 100. Furthermore, since both first links 61 are mounted on gearbox 55, as gearbox 55 rotates counterclockwise around pivot 54, the first links 61 drive the entire cross link unit 6 to flip upwards, and gradually form a hemispherical structure with the remaining cross link units 6, thus obtaining a spherical robot.

[0064] During the transition from ball mode to wheel mode, the branch arm 4 supports the ground, and the extension and retraction motor drives the second drive wheel 52 to rotate counterclockwise. The second drive wheel 52 drives the second driven wheel 53 to rotate clockwise through meshing transmission, thereby causing the gearbox 55 to rotate clockwise around the rotating shaft 54. During the rotation of the gearbox 55, the second bevel gears 562 of the two sets of transmission gear pairs 56 rotate clockwise around the rotating shaft 54. Because the bevel gear pairs in the two sets of transmission gear pairs 56 are symmetrically arranged, when the first bevel gear 561 remains stationary, the two second bevel gears 562 will be driven by opposite directions. Among them, the second bevel gear 562 on the left is driven by the first bevel gear 561 to rotate clockwise while revolving clockwise, and drives the second rotating shaft 563 to rotate clockwise. The second shaft 563, through the meshing of the first spur gear 564 and the second spur gear 565, drives the transmission shaft corresponding to the first connecting rod 61 to rotate counterclockwise, thereby causing the first connecting rod 61 on the right to swing to the right. At the same time, the second bevel gear 562 on the right, while revolving clockwise, is driven to rotate counterclockwise, and drives the second shaft 563 to rotate counterclockwise. The second shaft 563, through the meshing of the first spur gear 564 and the second spur gear 565, drives the transmission shaft corresponding to the first connecting rod 61 to rotate clockwise, thereby causing the first connecting rod 61 on the left to swing to the left. At this time, the cross linkage unit 6 performs a retraction movement and moves away from the central axis of the outer hub 100. Furthermore, since both first links 61 are mounted on gearbox 55, as gearbox 55 rotates clockwise around pivot 54, the entire cross link unit 6 is flipped downwards via the first links 61, causing the retracted cross link unit 6 to gradually attach to the side wall of outer hub 100, thereby obtaining a wheeled robot.

[0065] In this embodiment, the deployment and retraction drive unit 5 abandons the traditional gearbox 55 arrangement and adopts a structural design where the rotating shaft 54 ​​is fixed and the gearbox 55 rotates around the rotating shaft 54. Combined with the meshing transmission of the transmission gear pair 56, it can drive the two first connecting rods 61 to complete the opposite lateral swing motion, realizing the retraction and deployment of the cross linkage unit 6. On the other hand, it can also drive the entire cross linkage unit 6 to flip up and down through the first connecting rods 61. When the robot switches to wheel mode, the cross linkage unit 6 can be retracted and attached to the side wall of the outer hub 100. This design can avoid contact friction between the connecting rods and the ground, eliminate the hidden danger of connecting rod collision deformation, improve the working stability of the cross linkage unit 6, and further extend its service life.

[0066] Furthermore, to reduce the number of deploying and retracting motors, this embodiment designs the deploying and retracting drive unit 5 as a single active and multiple passive linkage structure. That is, only one set of deploying and retracting drive units 5 is retained as the active drive structure, and the remaining deploying and retracting drive units 5 are all set as passive drive structures. The passive units remove the deploying and retracting motor, the second active wheel 52 and the second passive wheel 53. Adjacent deploying and retracting drive units 5 are connected by a linkage transmission unit 7 to realize the transmission of driving force. Thus, only a single deploying and retracting motor can drive all deploying and retracting drive units 5 to move synchronously, driving all cross linkage units 6 to complete the deploying, retracting and flipping movements.

[0067] Specifically, in combination Figure 7 and Figure 9 As shown in the structure, each linkage transmission unit 7 is mainly composed of a first transmission link 71, a second transmission link 72, and a third transmission link 73, which are hinged end to end in sequence. The first transmission link 71 and the third transmission link 73 are both L-shaped links, and their vertical segments are rotatably connected to the outer walls of two adjacent gearboxes 55 by pins. The two ends of the second transmission link 72 are rotatably hinged to the transverse segments of the first transmission link 71 and the third transmission link 73 by pins, respectively.

[0068] When the gearbox 55 in the active drive structure rotates around the rotary shaft 54, it synchronously drives the two first transmission links 71 connected to it to rotate. Under the constraint of the second transmission link 72, the first transmission link 71 deflects outward and drives the second transmission link 72 to rotate synchronously. The second transmission link 72 then drives the adjacent gearbox 55 to rotate around their respective rotary shafts 54 through the third transmission link 73, thereby realizing the linkage rotation of all gearboxes 55. At the same time, under the meshing transmission action of the transmission gear pair 56, all cross linkage units 6 synchronously complete the unfolding and retracting actions and the flipping action.

[0069] The deployment and retraction module in this embodiment relies on the linkage transmission characteristics of the linkage transmission unit 7 to achieve synchronous movement of all cross linkage units 6 under the drive of a single motor. This reduces the number of motors, simplifies the structure, reduces the overall energy consumption, and extends the continuous operation time of the robot.

[0070] The working principle and workflow of a ball-wheel composite multimodal mobile robot with branched legs and arms according to the present invention will be described in detail below with reference to the accompanying drawings.

[0071] The robot's initial state is set to wheeled mode, with the supporting legs 48 of the left and right branch arms 4 both in a downward-facing, ground-supporting position, thus maintaining the robot's upright posture. Figure 1 and Figure 2 As shown.

[0072] The process of switching from wheel mode to ball mode:

[0073] The retractable motor drives the second drive wheel 52 to rotate clockwise. The second drive wheel 52 drives the second driven wheel 53 to rotate counterclockwise through meshing transmission, thereby causing the gearbox 55 to rotate counterclockwise around the rotating shaft 54. During the rotation of the gearbox 55, the second bevel gears 562 of the two sets of transmission gear pairs 56 rotate counterclockwise around the rotating shaft 54. Because the bevel gear pairs in the two sets of transmission gear pairs 56 are symmetrically arranged, when the first bevel gear 561 remains stationary, the two second bevel gears 562 will be driven by opposite directions. Among them, the second bevel gear 562 on the left side is driven by the first bevel gear 561 to rotate counterclockwise while revolving counterclockwise, and drives the second rotating shaft 563 to rotate counterclockwise. The second rotating shaft 563, through the meshing transmission of the first spur gear 564 and the second spur gear 565, drives the transmission shaft corresponding to the first connecting rod 61 to rotate clockwise, thereby causing the first connecting rod 61 on the right to swing to the left. At the same time, the second bevel gear 562 on the right is driven to rotate clockwise while revolving counterclockwise, and drives the second rotating shaft 563 to rotate clockwise. The second rotating shaft 563, through the meshing transmission of the first spur gear 564 and the second spur gear 565, drives the transmission shaft corresponding to the first connecting rod 61 to rotate counterclockwise, thereby causing the first connecting rod 61 on the left to swing to the right. At this time, the ends of the two first connecting rods 61 swing inward synchronously under the drive of the unfolding drive unit 5. The two parallelogram linkage mechanisms connected in series produce coordinated deformation and exhibit an overall unfolding action. That is, the first connecting rod 61 pushes the second connecting rod 62 to move away from the outer hub 100, and the second connecting rod 62 simultaneously pushes the third connecting rod 63 to move away from the outer hub 100. The single cross linkage unit 6 gradually unfolds. Because the first link 61, the second link 62, and the third link 63 all adopt an arc-shaped structure, the ends of all the intersecting link units 6 gradually converge towards the central axis of the outer hub 100, eventually forming a hemispherical structure. This structure, combined with the outer hub 100, forms a complete spherical structure, allowing the robot to switch from wheeled mode to spherical mode. Figure 5 and Figure 6 The state shown.

[0074] When the robot in ball mode needs to move, the supporting legs 48 of the left and right branch arms 4 both flip upwards, as... Figure 8In the indicated state, according to the robot's preset travel direction, the steering motor 21 drives the first drive wheel 22 to rotate. The first drive wheel 22 drives the worm 25 to rotate via the first driven wheel 23. The worm 25 further drives the worm wheel 24 to rotate, thereby driving the internal gear ring 1 to deflect around the line connecting the two first rotating shafts 13, adjusting the attitude angle of the internal gear ring 1 within the spherical robot, so that the outer ring surface of the internal gear ring 1 faces the travel direction, thus completing the adjustment of the travel direction. Subsequently, the travel motor 31 drives the drive bevel gear 32 to rotate. The drive bevel gear 32 drives the driven spur gear 34 to rotate synchronously via the driven bevel gear 33. The driven spur gear 34 applies a driving force to the internal gear ring 1. Since the outer hub 100 is in contact with the ground, when the output torque of the travel motor 31 is less than the static friction force between the ground and the outer hub 100, the outer hub 100 and the internal gear ring 1 remain stationary under the action of this static friction force. At this time, the driving force of the driven spur gear 34 on the internal gear ring 1 acts in the opposite direction to the driven spur gear 34. The driven spur gear 34 drives the clamping and positioning bracket 36 to move along the tooth extension direction of the internal gear ring 1 through the driven bevel gear 33 and the driving bevel gear 32. When the output torque of the travel motor 31 is greater than the maximum static friction force between the ground and the outer hub 100, the clamping and positioning bracket 36 remains stationary relative to the internal gear ring 1, and the driven spur gear 34 drives the internal gear ring 1 to rotate. The internal gear ring 1 then drives the outer hub 100 to move forward or backward. This realizes the forward or backward movement of the spherical robot.

[0075] The process of switching from ball mode to wheel mode:

[0076] The retractable motor drives the second drive wheel 52 to rotate counterclockwise. The second drive wheel 52 drives the second driven wheel 53 to rotate clockwise through meshing transmission, thereby causing the gearbox 55 to rotate clockwise around the rotating shaft 54. During the rotation of the gearbox 55, the second bevel gears 562 of the two sets of transmission gear pairs 56 rotate clockwise around the rotating shaft 54. Because the bevel gear pairs in the two sets of transmission gear pairs 56 are symmetrically arranged, when the first bevel gear 561 remains stationary, the two second bevel gears 562 will be driven by opposite directions. Among them, the second bevel gear 562 on the left is driven by the first bevel gear 561 to rotate clockwise while revolving clockwise, and drives the second rotating shaft 563 to rotate clockwise. The second rotating shaft 563 drives the transmission shaft corresponding to the first connecting rod 61 to rotate counterclockwise through the meshing transmission of the first spur gear 564 and the second spur gear 565, thereby causing the first connecting rod 61 on the right to swing to the right; at the same time, the second bevel gear 562 on the right is driven to rotate counterclockwise while revolving clockwise, and drives the second rotating shaft 563 to rotate counterclockwise. The second rotating shaft 563 drives the transmission shaft corresponding to the first connecting rod 61 to rotate clockwise through the meshing of the first spur gear 564 and the second spur gear 565. This causes the first connecting rod 61 on the left to swing to the left. At this time, the ends of the two first connecting rods 61 swing outward synchronously under the drive of the extension and retraction drive unit 5. The two parallelogram linkages in series deform in opposite directions and move together. That is, the first connecting rod 61 pulls the second connecting rod 62 to retract towards the outer hub 100. The second connecting rod 62 pulls the third connecting rod 63 to retract towards the outer hub 100. At the same time, as the gearbox 55 rotates clockwise around the rotating shaft 54, the first connecting rod 61 drives the entire cross linkage unit 6 to flip downward, so that the retracted cross linkage unit 6 gradually attaches to the side wall of the outer hub 100. The outer hub 100 independently contacts and supports the ground. The robot completes the form switch from ball mode to wheel mode.

[0077] When the robot in wheeled mode needs to move, the steering drive module 2 controls the internal gear ring 1 to be coaxial with the outer wheel hub 100, and the supporting legs 48 of the left and right branch arms 4 both flip upwards, as... Figure 3 and Figure 4The state is shown. Subsequently, the travel motor 31 drives the driving bevel gear 32 to rotate, and the driving bevel gear 32 drives the driven spur gear 34 to rotate synchronously through the driven bevel gear 33. The driven spur gear 34 applies a driving force to the internal gear ring 1. Since the outer hub 100 is in contact with the ground, when the output torque of the travel motor 31 is less than the static friction force of the ground on the outer hub 100, the outer hub 100 and the internal gear ring 1 remain stationary under the action of this static friction force; at this time, the driving force of the driven spur gear 34 on the internal gear ring 1 acts in the opposite direction to the driven spur gear 34, and the driven spur gear 34 drives the clamping and positioning bracket 36 to move along the tooth extension direction of the internal gear ring 1 through the driven bevel gear 33 and the driving bevel gear 32. When the output torque of the travel motor 31 is greater than the maximum static friction force of the ground on the outer hub 100, the clamping and positioning bracket 36 remains stationary relative to the internal gear ring 1, and the driven spur gear 34 drives the internal gear ring 1 to rotate, and the internal gear ring 1 then drives the outer hub 100 to achieve forward or backward movement. This enables the robot in wheeled mode to move forward or backward.

[0078] When the robot in wheeled mode needs to turn, the joint servos on both sides control the two supporting legs 48 to rotate to different degrees, so that the two branch legs 4 are adjusted to an asymmetrical arrangement, thereby adjusting the robot's center of gravity to shift and thus achieving steering control in wheeled mode.

[0079] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions created by the present invention, and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions created by the present invention without departing from the essence and scope of the technical solutions created by the present invention.

Claims

1. A ball-wheel composite multimodal mobile robot with branched legs and arms, characterized in that, include: The outer hub has its rim supported on the ground. An internal drive steering mechanism, installed inside the outer wheel hub, is used to realize the robot's propulsion drive and steering control in ball mode; The ball wheel switching mechanism includes two folding modules symmetrically arranged on the left and right sides of the outer wheel hub, each of which can perform an unfolding or retracting action; When the robot is in wheel mode, the two folding modules unfold, forming hemispherical structures on both sides of the outer wheel hub, and the whole structure forms a spherical structure, thus switching the robot from wheel mode to spherical mode; when the two folding modules retract, they fit snugly against both sides of the outer wheel hub, and the outer wheel hub independently contacts and supports the ground, thus switching the robot from spherical mode to wheel mode. Each folding module includes an unfolding drive unit and a cross linkage unit. There are multiple unfolding drive units, which are evenly distributed along the circumference of the outer hub. Each unfolding drive unit corresponds to a cross linkage unit and can drive the corresponding cross linkage unit to perform unfolding or folding actions to complete the switching between the robot's ball mode and wheel mode. Each cross-link unit includes an arc-shaped first link, second link, and third link. There are two of each of the first, second, and third links, which are evenly divided into two groups. The first, second, and third links in each group are connected end to end in sequence. The first end of the first link in both groups is connected to the extension and retraction drive unit, and can swing laterally relative to each other under the drive of the extension and retraction drive unit. The second links in the two groups are arranged crosswise and connected by hinges. The ends of the third links in the two groups are connected by hinges, forming two parallelogram linkage mechanisms arranged in series.

2. The ball-wheel composite multimodal mobile robot with branched legs and arms according to claim 1, characterized in that, The internal drive steering mechanism includes an internal gear ring, a steering drive module, and a travel drive module. The internal gear ring is coaxially disposed inside the outer hub and is rotatably connected to the outer hub. The steering drive module is connected to the internal gear ring and can drive the internal gear ring to rotate relative to the outer hub to achieve steering adjustment in the robot's ball mode. The travel drive module can drive the internal gear ring to rotate around its own axis so that the internal gear ring can drive the robot to complete forward or backward movements.

3. The ball-wheel composite multimodal mobile robot with branched legs and arms according to claim 2, characterized in that, The steering drive module includes a steering motor, a worm gear, and a worm. The steering motor is fixed to the inner ring wall of the outer hub and can drive the worm to rotate. The worm gear is connected to the internal gear ring and meshes with the worm.

4. A ball-wheel composite multimodal mobile robot with branched legs and arms according to claim 2, characterized in that, The travel drive module includes a travel motor, a driven spur gear, and a clamping and positioning bracket. The clamping and positioning bracket is clamped on the left and right sides of the internal gear ring and forms a sliding fit with the internal gear ring. The travel motor is fixed to the clamping and positioning bracket and can drive the driven spur gear to rotate. The driven spur gear meshes with the internal gear ring to drive the internal gear ring to rotate around its own axis.

5. A ball-wheel composite multimodal mobile robot with branched legs and arms according to claim 2, characterized in that, The internal drive steering mechanism also includes two branch legs symmetrically mounted on the left and right sides of the travel drive module. Each branch leg can perform up-and-down flipping motion. When the two branch legs are flipped down to support the ground, the robot can be kept upright. When the branch legs are flipped up, the robot's center of gravity can be adjusted by the left and right swaying of the two branch legs to achieve steering adjustment in the robot's wheel mode.

6. A ball-wheel composite multimodal mobile robot with branched legs and arms according to claim 1, characterized in that, Each deployment and recovery drive unit includes a deployment and recovery motor, a second driving wheel, a second driven wheel, a rotating shaft, a gearbox, and two sets of transmission gear pairs. The deployment and recovery motor and the rotating shaft are both fixedly mounted on the outer hub. The deployment and recovery motor can drive the second driving wheel to rotate. The second driven wheel is fixedly connected to the gearbox, and both are sleeved on the rotating shaft. The second driving wheel and the second driven wheel mesh with each other. The two sets of transmission gear pairs are arranged in opposite directions and side by side inside the gearbox, and correspond one-to-one with the two first connecting rods. Each set of transmission gear pairs can transmit the rotational motion of the gearbox to the corresponding first connecting rod to drive the two first connecting rods to perform opposite lateral swing motion.

7. A ball-wheel composite multimodal mobile robot with branched legs and arms according to claim 6, characterized in that, Each transmission gear pair includes a first bevel gear, a second bevel gear, a first spur gear, and a second spur gear. The first bevel gear is mounted on a rotating shaft and remains fixed. The second bevel gear is rotatably mounted on a gearbox and meshes with the first bevel gear. The first spur gear is connected to the second bevel gear and can rotate with the second bevel gear. The second spur gear is connected to the corresponding first connecting rod and meshes with the first spur gear.

8. A ball-wheel composite multimodal mobile robot with branched legs and arms according to claim 6, characterized in that, Each folding module also includes multiple linkage transmission units. Two adjacent folding and retracting drive units are connected by a linkage transmission unit. Only one folding and retracting drive unit is an active drive structure, while the other folding and retracting drive units have the folding and retracting motor, the second drive wheel, and the second driven wheel removed.

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