Wheel-legged reconfigurable planetary vehicle

Abstract

The application provides a wheel-foot type reconfigurable star planet vehicle and relates to the technical field of star planet exploration. The star planet vehicle has passive terrain adaptation and suspension active adjustment functions, which are beneficial to meet the diversified needs of the star planet vehicle when passing through different terrains. Through control combination of two degrees of freedom, the star planet vehicle can realize a wheel type passive self-adaptive moving mode and a foot type walking mode, which is beneficial to improve the passing ability and task execution efficiency of the star planet vehicle in complex terrains and reduce the overall energy consumption of the star planet exploration task in complex terrains. Moreover, the design of the double closed loop structure is beneficial to increase the connecting points and force transmission paths between the multi-link structure and the vehicle frame, improve the stiffness and carrying capacity of the suspension, and improve the reliability of the star planet vehicle. In addition, the metamorphic characteristics of the pentagonal ring make the equivalent stiffness of the suspension reconfigurable, which provides more possibilities for the reconstruction of the suspension of the star planet vehicle and further improves the rapid passing ability and task execution efficiency of the star planet vehicle in complex terrains.

Description

Technical Field

[0001] This invention relates to the field of planetary exploration technology, and more specifically, to a wheel-footed reconfigurable planetary rover. Background Technology

[0002] When performing exploration missions, planetary rovers often face complex terrains such as rugged, uneven, soft, and variable surfaces. Traditional wheeled planetary rovers have fixed suspension configurations, which limits their obstacle-crossing capabilities. Furthermore, planetary rovers are prone to wheel bounce and instability due to ground impacts, which restricts their high-speed performance and consequently affects their ability to traverse complex terrains quickly. Summary of the Invention

[0003] To at least partially address at least one aspect of the aforementioned problems, this invention provides a wheel-foot reconfigurable planetary vehicle. The planetary vehicle includes a frame, a passive terrain adaptation mechanism, a locking structure, multiple multi-link mechanisms, multiple drive units, and multiple wheels. Each multi-link mechanism includes a four-bar assembly and a two-bar assembly. The four-bar assembly is rotatably connected to the frame and forms a first closed loop. The two-bar assembly is rotatably connected at both ends to the four-bar assembly and the frame, forming a second closed loop. The first and second closed loops together form a double-closed-loop structure with two degrees of freedom, one of which includes a pentagonal ring. The drive unit is driven by the multi-link mechanism and controls one of the two degrees of freedom. When the drive unit locks the corresponding degree of freedom, the double-closed-loop structure transforms into a single-degree-of-freedom structure. The length of the equivalent link of the pentagonal ring changes with the pose of the pentagonal ring. The wheels are mounted on the lower end of each multi-link mechanism. The passive terrain adaptation mechanism is movably connected to the vehicle frame and the multiple multi-link mechanisms. The passive terrain adaptation mechanism is equipped with a locking structure. The locking or unlocking of the locking structure controls the other of the two degrees of freedom. When the locking structure is unlocked, the passive terrain adaptation mechanism and the multiple multi-link mechanisms work together to balance the ground load of each wheel.

[0004] Optionally, the multi-link mechanism includes a rocker arm and two adjacent set links. The rocker arm has a first connecting part for mounting the wheel. The multi-link mechanism is configured to move to a singular point position where the transmission angle of the two set links is zero. The multi-link mechanism is movably connected to the passive terrain adaptation mechanism at a position outside the set links.

[0005] Optionally, the four-bar linkage includes the swing arm, which is further provided with a second connecting part. The second connecting part is rotatably connected to the frame at the end position of the frame in the front-rear direction. The axis of the two-bar linkage and the frame that are rotatably connected is arranged parallel to the axis of the second connecting part.

[0006] Optionally, the two set links correspond to the two sides of the second closed loop respectively, the drive unit is driven and connected to the second closed loop, and the multi-link mechanism is provided with a fourth connecting part outside the second closed loop and the swing arm. The fourth connecting part is used to be movably connected to the passive terrain adaptation mechanism.

[0007] Optionally, in the four-bar linkage assembly, the three links other than the swing arm are a first link, a second link, and a third link that are rotatably connected in sequence; the first link is rotatably connected to the swing arm at a position spaced apart from the second link, and the third link is provided with a third connecting part at a position spaced apart from the second link; the two links of the two-bar linkage assembly are a fourth link and a fifth link that are rotatably connected, and the fifth link is rotatably connected to the frame at the end away from the fourth link; The third connecting part is rotatably connected to the frame and coaxially arranged with the second connecting part, and the fourth link is rotatably connected to either the first link or the second link at the end away from the fifth link; Alternatively, the third connecting part is rotatably connected to the frame and spaced apart from the second connecting part, and the fourth link is rotatably connected at the end away from the fifth link to any one of the first link, the second link, and the third link.

[0008] Optionally, the drive unit is mounted on the vehicle frame, and the output end of the drive unit is connected to one of the two links of the two-bar linkage that is rotatably connected to the vehicle frame.

[0009] Optionally, both of the setting links are provided with corner limiting blocks, and the abutment of the two corner limiting blocks limits the extreme angle of relative rotation of the two setting links; And / or, the swing arm includes a first segment and a second segment; the lower end of the first segment is rotatably connected to the frame, the upper end of the first segment is rotatably connected to the first connecting rod, the upper end of the second segment is fixedly connected to the lower end of the first segment, the second segment is inclined relative to the first segment, and from top to bottom, the distance from a point on the second segment to the center of the frame gradually increases in the front-rear direction, and the lower end of the second segment is provided with the first connecting part.

[0010] Optionally, the number of multi-link mechanisms is four, and the four multi-link mechanisms are respectively arranged in the four corner areas of the vehicle frame; when the locking structure is unlocked, the passive terrain adaptation mechanism is configured to: cause the two multi-link mechanisms located in each pair of diagonally opposite areas of the vehicle frame to link together and cause the vertical distance between the corresponding two wheels and the vehicle frame to increase or decrease simultaneously; cause the two multi-link mechanisms located in each pair of adjacent corner areas of the vehicle frame to link together and cause the vertical distance between the corresponding two wheels and the vehicle frame to increase and decrease respectively.

[0011] Optionally, the passive terrain adaptation mechanism includes a balance bar and four force transmission components; the balance bar is arranged in the left-right direction and is rotatably connected to the vehicle frame about a vertical axis at the middle position in the left-right direction; the four force transmission components are arranged one-to-one with the four multi-link mechanisms, and two force transmission components are movably connected to both ends of the balance bar in the left-right direction, and the force transmission component is movably connected to the corresponding multi-link mechanism at the end away from the balance bar; The locking structure includes a first clutch, which is disposed at the connection between the stabilizer bar and the frame, and is used to lock or unlock the rotation of the stabilizer bar relative to the frame.

[0012] Optionally, the wheel-foot reconfigurable planetary vehicle has a wheeled passive adaptive mobility mode, a foot-foot walking mode, and an active-passive composite mobility mode; In the wheeled passive adaptive movement mode, one of the two degrees of freedom of the dual closed-loop structure is restricted and the dual closed-loop structure is transformed into a single degree of freedom structure. The passive terrain adaptation mechanism is unlocked by the locking structure. The passive terrain adaptation mechanism transmits force between multiple multi-link mechanisms, so that each multi-link mechanism works together to balance the ground load of each wheel. In the legged walking mode, the passive terrain adaptation mechanism is locked by the locking structure, and each of the multi-link mechanisms is independently controlled by the corresponding drive unit. By controlling the coordinated action of multiple multi-link mechanisms, the alternating lifting and landing of multiple wheels is achieved to realize legged walking. In the active-passive composite movement mode, the drive unit operates to drive the multi-link mechanism to move, the passive terrain adaptation mechanism is unlocked by the locking structure, and the passive terrain adaptation mechanism transmits force among the multiple multi-link mechanisms.

[0013] The wheel-foot reconfigurable planetary rover of this invention has the following technical advantages: The rover possesses reconfigurability, enabling passive terrain adaptation and active suspension adjustment. This facilitates meeting the diverse needs of the rover when traversing different terrains. Through the control combination of two degrees of freedom, the rover can achieve both wheeled passive adaptive movement and footed walking modes, improving its mobility and mission efficiency in complex terrains and reducing the overall energy consumption of planetary exploration missions in complex terrain. Furthermore, the dual-closed-loop structure design increases the connection points and force transmission paths between the multi-link structure and the frame, enhancing the stiffness and load-bearing capacity of the rover's suspension, thus improving the fatigue life of the multi-link mechanism and the reliability of the rover. In addition, the variable-cell characteristic of the pentagonal ring allows the equivalent stiffness of the suspension to be reconfigured according to the pose of each multi-link mechanism, providing more possibilities for suspension reconfiguration and further enhancing the rover's mobility and mission efficiency in complex terrains. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the mechanism of the planetary rover in an embodiment of the present invention; Figure 2 for Figure 1 The diagram shows the principle of the equivalent rod when the second closed loop of the planetary rover is a pentagonal ring. Figure 3 This is a schematic diagram showing the principle of the equivalent rod when the second closed loop is a pentagonal ring in another embodiment of the present invention; Figure 4 This is a schematic diagram showing the principle of the equivalent rod when the first closed loop is a pentagonal ring in another embodiment of the present invention; Figure 5 for Figure 1 A three-dimensional structural diagram of the planetary rover shown; Figure 6 for Figure 5 A side view of the planetary rover shown; Figure 7 for Figure 5 The diagram shows the structure of the passive terrain adaptation mechanism of the planetary rover.

[0015] Explanation of reference numerals in the attached figures: 1-Frame; 2-Passive terrain adaptation mechanism; 21-Stabilizer bar; 22-Force transmission component; 3-Locking structure; 31-First clutch; 4-Multi-link mechanism; 410-Four-link assembly; 420-Two-link assembly; 41-Swing bar; 411-First link segment; 412-Second link segment; 42-First link; 43-Second link; 44-Third link; 45-Fourth link; 46-Fifth link; 47-Equivalent link; 401-First connecting part; 402-Second connecting part; 403-Third connecting part; 404-Fourth connecting part; 405-Angle limit block; 5-Drive unit; 6-Wheel; 71-Vertical mounting shaft. Detailed Implementation

[0016] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0017] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0018] In the description of this specification, the references to terms such as "embodiment," "one embodiment," "some implementations," "exemplary," and "one implementation," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or implementation is included in at least one embodiment or implementation of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or implementation. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or implementations.

[0019] The terms "first," "second," etc., 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. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature.

[0020] In the attached figures, the X-axis represents the front-to-back position, with the positive direction of the X-axis (i.e., the direction the arrow points) indicating the front and the negative direction indicating the rear. The Y-axis represents the horizontal direction and is designated as the left-to-right position, with the positive direction of the Y-axis (i.e., the direction the arrow points) indicating the right and the negative direction indicating the left. The Z-axis represents the vertical direction, i.e., the up-down position, with the positive direction of the Z-axis (i.e., the direction the arrow points) indicating up and the negative direction indicating down. It should be noted that the aforementioned representations of the X, Y, and Z axes are merely for the convenience of describing the 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 the invention.

[0021] like Figure 1 and Figure 2 As shown, an embodiment of the present invention provides a wheel-foot type reconfigurable planetary vehicle. The planetary vehicle includes a frame 1, a passive terrain adaptation mechanism 2, a locking structure 3, multiple multi-link mechanisms 4, multiple drive units 5, and multiple wheels 6. Each of the multi-link mechanisms 4 includes a four-bar assembly 410 and a two-bar assembly 420. The four-bar assembly 410 is rotatably connected to the frame 1 and forms a first closed loop. The two ends of the two-bar assembly 420 are rotatably connected to the four-bar assembly 410 and the frame 1, respectively, and form a second closed loop. The first closed loop and the second closed loop together constitute a double closed loop structure with two degrees of freedom, one of which is a pentagonal ring; the driving unit 5 is driven and connected to the multi-link mechanism 4 and controls one of the two degrees of freedom. When the driving unit 5 controls the corresponding degree of freedom to lock, the double closed loop structure becomes a single degree of freedom structure. The length of the equivalent rod 47 of the equivalent four-bar linkage of the pentagonal ring changes with the pose of the pentagonal ring; the wheel 6 is installed at the lower end of the multi-link mechanism 4.

[0022] The passive terrain adaptation mechanism 2 is movably connected to the vehicle frame 1 and the multiple multi-link mechanisms 4 respectively. The passive terrain adaptation mechanism 2 is equipped with the locking structure 3. The locking or unlocking of the locking structure 3 controls the other of the two degrees of freedom. When the locking structure 3 is unlocked, the passive terrain adaptation mechanism 2 and the multiple multi-link mechanisms 4 work together to balance the ground load of each wheel 6.

[0023] In mechanical kinematics, a degree of freedom refers to the number of independent movements in a mechanism. For the double-closed-loop structure of this invention, it has two degrees of freedom, meaning it has two independent possibilities of movement. Controlling a degree of freedom means actively intervening in its motion state to make it move in the desired manner or remain in a specific state. The drive unit 5 and the locking structure 3 control the two degrees of freedom respectively, without either the drive unit 5 or the locking structure 3 simultaneously restricting both degrees of freedom of the double-closed-loop structure. This means that as long as one degree of freedom is not locked, the multi-link mechanism 4 can deform to adjust the vertical distance between the wheel 6 and the frame 1.

[0024] It should be understood that the four-bar linkage 410 has four links, and the two-bar linkage 420 has two links, such as... Figure 1 As shown, for example, the four links of the four-bar linkage 410 are the swing arm 41, the first link 42, the second link 43 and the third link 44, and the two links of the two-bar linkage 420 are the fourth link 45 and the fifth link 46. The multi-bar mechanism 4 has a total of six links, and the six links and the frame 1 together constitute a double closed-loop structure with two degrees of freedom.

[0025] The four-bar linkage 410 is rotatably connected to the frame 1 to form a first closed loop. That is, the first closed loop includes at least four sides, corresponding to the rocker arm 41, the first link 42, the second link 43, and the third link 44, respectively. The wheel 6 is mounted via, for example, the rocker arm 41. Both the first and second closed loops contain pentagonal rings, such as those shown in the reference diagram. Figure 4 As shown, in some scenarios, the first closed loop is a pentagonal ring, with its fifth side corresponding to the frame 1.

[0026] The two-link assembly 420 is rotatably connected at both ends to the four-link assembly 410 and the frame 1, forming a second closed loop. When the second closed loop is a quadrilateral loop, it shares one side with the first closed loop. Three of the four sides correspond to the fourth link 45, the fifth link 46, and the frame 1, respectively, and the other side corresponds to the swing arm 41 or the third link 44 (see reference). Figure 4 (As shown). In some scenarios, the second closed loop is a pentagonal ring, and the second closed loop shares two sides with the first closed loop, for example, see reference. Figures 1 to 3 As shown, its five sides correspond to the fourth link 45, the fifth link 46, the frame 1, the swing arm 41, and the first link 42, respectively.

[0027] From the perspective of calculating the degrees of freedom of the mechanism, the pentagonal ring itself has two degrees of freedom. The double closed-loop design does not add any new independent degrees of freedom, and the degrees of freedom of the entire double closed-loop structure remain two.

[0028] The design employs a double closed-loop structure, with multiple connection points between the multi-link mechanism 4 and the frame 1. This effectively increases the constraint points between the multi-link mechanism 4 and the frame 1, making the support of the multi-link mechanism 4 on the frame 1 more stable. At the same time, the number of force transmission paths between the multi-link mechanism 4 and the frame 1 increases. More force transmission paths allow the same load to be distributed to multiple connection points and multiple links, which helps to reduce the stress on some links. Therefore, the double closed-loop structure improves the stiffness and deformation resistance of the multi-link mechanism, which is beneficial for withstanding the ground impact load transmitted by the wheel 6, and also helps to improve the fatigue life and reliability of the multi-link mechanism 4.

[0029] The drive unit 5 is driven by a link (defined as the active link) in the multi-link mechanism 4. By outputting a driving torque, the drive unit 5 drives the active link to move relative to an adjacent component, causing the double-closed-loop structure to deform and achieving drive control of one of the two degrees of freedom. This degree of freedom manifests as the link in the multi-link mechanism 4 connected to the wheel 6 moving relative to the frame 1 when the drive unit 5 drives the multi-link mechanism 4 to deform, thus actively adjusting the vertical distance between the wheel 6 and the frame 1. This degree of freedom can be defined as the active degree of freedom. The drive unit 5 can also lock the corresponding active link to fix it relative to an adjacent component, thus restricting this active degree of freedom. Therefore, the drive unit 5 can achieve complete control of the active degree of freedom through both driving and locking methods.

[0030] When the drive unit 5 locks the corresponding degree of freedom, the double-closed-loop structure transforms into a structure with only one degree of freedom. Correspondingly, one rotational joint of the pentagonal ring is constrained. Kinematically, the pentagonal ring is equivalent to an equivalent four-bar linkage. Three of the links in this equivalent four-bar linkage correspond to the original three sides of the pentagonal ring, and the other link is equivalent to link 47, as shown below. Figures 2 to 4 As shown, the light-colored dashed lines schematically indicate the position of the equivalent rod 47. Figure 2 In this design, the second closed loop is a pentagonal ring, with its five sides corresponding to the fourth link 45, the fifth link 46, the frame 1, the swing arm 41, and the first link 42, respectively. When, for example, the fifth link 46 is the active link and is locked, the relative positions of the fifth link 46 and the frame 1 are fixed, which can be equivalent to an equivalent link 47. The pentagonal ring degenerates into an equivalent four-link. However, unlike a traditional four-link, the length of the equivalent link 47 is not a fixed value but changes with the pose of the pentagonal ring. That is, when the drive unit 5 drives the multi-link mechanism 4 to different positions, the position of the fifth link 46 is different, and the length of the equivalent link 47 is different. This means that the kinematic characteristics of the equivalent four-link (such as link curves and transmission angles) will change with the pose of the double-closed-loop structure.

[0031] The structure of the passive terrain adaptation mechanism 2 is not a limitation and will be described exemplarily later. The locking structure 3 is used to control whether the passive terrain adaptation mechanism 2 is working. That is, the locking structure 3 is used to lock or unlock the passive terrain adaptation mechanism 2, thereby controlling the other of the two degrees of freedom. This degree of freedom is manifested in that when the locking structure 3 unlocks the passive terrain adaptation mechanism 2, the passive terrain adaptation mechanism 2 can freely transmit forces between the various multi-link mechanisms 4, realizing motion coupling and load transmission between multiple multi-link mechanisms 4, which can be defined as a passive degree of freedom. The passive degrees of freedom of each multi-link mechanism 4 are linked together, and each multi-link mechanism 4 can automatically coordinate its movement according to terrain changes, so that multiple multi-link mechanisms 4 work together to balance the ground load of each wheel 6, realizing the passive adjustment function of the planetary rover's suspension. When the locking structure 3 is locked, the passive terrain adaptation mechanism 2 is locked and cannot transmit forces between the various multi-link mechanisms 4. The passive degrees of freedom of each multi-link mechanism 4 are restricted, and each multi-link mechanism 4 only has one degree of freedom. The active movements of each multi-link mechanism 4 are independent of each other. Therefore, locking structure 3 achieves the activation or locking control of passive degrees of freedom by switching between locked and unlocked states.

[0032] When necessary, the drive unit 5 can also drive the double closed-loop structure to deform and adjust the position of the multi-link mechanism 4, thereby realizing the active adjustment function of the planetary vehicle's suspension (at this time, the locking structure 3 can be locked or unlocked, and it is not a restriction). This enables the reconstruction of the planetary vehicle's suspension. For example, the vertical distance between the wheels 6 and the frame 1 can be adjusted as needed to change the ground clearance of the frame 1 to adapt to the passage requirements of different obstacle heights and avoid the bottom of the frame 1 scraping against the obstacle; or the span between the front and rear wheels 6 can be adjusted to change the wheelbase of the planetary vehicle to adapt to the stability requirements under different terrain conditions. For example, when the planetary vehicle needs to drive on soft terrain, the drive unit 5 can adjust the position of the multi-link mechanism 4 to increase the span between the front and rear wheels 6, that is, extend the wheelbase, thereby reducing the pitch angle change of the frame 1, improving the driving stability of the planetary vehicle, and dispersing the pressure of the wheels 6 on the ground to reduce the risk of sinking. When the planetary vehicle needs to turn or pass through narrow terrain, the position of the multi-link mechanism 4 can be adjusted by the drive unit 5 to reduce the span between the front and rear wheels 6, i.e., shorten the wheelbase, thereby reducing, for example, the turning radius and improving the planetary vehicle's maneuverability. Alternatively, the pitch angle, roll angle, and other positional parameters of the frame 1 can be adjusted.

[0033] As explained above, each dual-closed-loop structure has two degrees of freedom, which can be understood to some extent as active and passive degrees of freedom, respectively. By controlling and combining the two degrees of freedom, multiple working modes can be achieved to meet the driving needs under different terrain conditions.

[0034] It has one or more of the following modes among multiple working modes: wheeled passive adaptive movement mode, legged walking mode, and active-passive composite movement mode.

[0035] In the wheeled passive adaptive movement mode, one of the two degrees of freedom of the dual closed-loop structure is restricted and the dual closed-loop structure is transformed into a single degree of freedom structure. The passive terrain adaptation mechanism 2 is unlocked by the locking structure 3. The passive terrain adaptation mechanism 2 transmits force among the multiple multi-link mechanisms 4, so that each of the multi-link mechanisms 4 works together to balance the ground load of each wheel 6.

[0036] For example, the drive unit 5 locks the active linkage. Figure 1 The fifth link 46 transforms from a double-closed-loop structure to a single-degree-of-freedom structure. The double-closed-loop structure only has passive degrees of freedom, which are transmitted to the passive terrain adaptation mechanism 2. The entire suspension of the planetary rover has only one passive degree of freedom. Through the mechanical linkage of the passive terrain adaptation mechanism 2, wheel-to-ground adhesion of the wheels 6 can be achieved, and the ground load of each wheel 6 can be balanced. Here, balancing the ground load of each wheel 6 does not mean that the ground load of each wheel 6 is exactly the same at all times. It mainly aims to make the contact pressure (i.e., ground load) between the four wheels 6 and the ground more evenly distributed, avoiding situations where a wheel 6 is completely suspended (ground load is zero) or a wheel 6 bears excessive load, causing it to sink into soft soil or be damaged. The wheeled passive adaptive movement mode is applicable to flat or slightly undulating terrain, ensuring the planetary rover's ability to travel quickly on flat or slightly undulating terrain.

[0037] In the legged walking mode, the passive terrain adaptation mechanism 2 is locked by the locking structure 3, and each of the multi-link mechanisms 4 is independently controlled by the corresponding drive unit 5. By controlling the coordinated action of multiple multi-link mechanisms 4, the multiple wheels 6 are alternately lifted and landed to achieve legged walking.

[0038] At this point, the passive terrain adaptation mechanism 2 cannot achieve the linkage of each multi-link mechanism 4, and the passive degrees of freedom of the double closed-loop structure corresponding to each multi-link mechanism 4 are constrained, giving the entire planetary vehicle's suspension four active degrees of freedom. Each drive unit 5 drives the deformation of its corresponding double closed-loop structure, thereby enabling the linkage in the multi-link mechanism 4 connected to the wheel 6 to ( Figure 1 The central swing arm 41 swings relative to the frame 1, allowing the vertical distance of each wheel 6 relative to the frame 1 to be independently adjustable. This enables the wheels 6 to move off the ground and into a walking gait. Through the coordinated control of multiple drive units 5, multiple swing arms 41 can be controlled to move in tandem, achieving alternating lifting and landing of multiple wheels 6, simulating a walking gait. This mode is suitable for complex and rugged terrain, capable of traversing large obstacles, ensuring the planetary vehicle's rapid passage capability in obstacle-crossing situations.

[0039] In the active-passive combined movement mode, the drive unit 5 works to drive the multi-link mechanism 4 to move, the passive terrain adaptation mechanism 2 is unlocked by the locking structure 3, and the passive terrain adaptation mechanism 2 transmits force among the multiple multi-link mechanisms 4.

[0040] At this point, the active degree of freedom of each multi-link mechanism 4 is independently controlled by the corresponding drive unit 5, and the passive degrees of freedom of each multi-link mechanism 4 are coupled together through the passive terrain adaptation mechanism 2. The entire planetary vehicle's suspension simultaneously possesses four active degrees of freedom and one passive degree of freedom. In this mode, the drive unit 5 can actively adjust the vehicle frame 1's ground clearance, pitch angle, roll angle, and other posture parameters, while the passive terrain adaptation mechanism 2 enables the four multi-link mechanisms 4 to work together to achieve wheel-to-ground adhesion for each wheel 6 and balance the ground load on each wheel 6. The coordinated operation of active control and passive adaptation ensures both the smoothness of the planetary vehicle's ride and improves its adaptability to terrain. This mode is suitable for terrains of moderate complexity, achieving a good balance between energy consumption and passability.

[0041] The first connecting part 401 is located at the lower end of the multi-link mechanism 4 and is used to install the wheel 6. Its specific structural form is not limited and can be a frame for installing the wheel 6, etc.

[0042] Furthermore, since the length of the equivalent link 47 of the equivalent four-bar linkage of the pentagonal ring changes with the pose of the pentagonal ring, when the drive unit 5 drives the multi-link mechanism 4 to move to different poses, the length of the equivalent link 47 of the equivalent four-bar linkage of the pentagonal ring changes, resulting in changes in the link curve shape, transmission angle variation law, and force transmission characteristics of the equivalent four-bar linkage, thus reconstructing the kinematic characteristics of passive terrain adaptation. This means that even if the structural parameters of the passive terrain adaptation mechanism 2 (such as the actual physical length of each link) remain unchanged, its passive adaptation characteristics (such as the ground load balancing ability of the wheel 6, the stiffness characteristics of the suspension, and the rate of change of the vertical distance between the wheel 6 and the frame 1 during passive terrain adaptation) will exhibit differentiated responses due to different poses of the pentagonal ring.

[0043] Specifically, taking the wheel 6 mounted at the lower end of the swing arm 41 as an example, when the passive adjustment function of the planetary rover's suspension is activated, the vertical distance between the wheel 6 and the frame 1 changes as the swing arm 41 swings relative to the frame 1. Since the length of the equivalent link 47 of the pentagonal ring's equivalent four-link changes with the position of the pentagonal ring, the change in the vertical distance between the wheel 6 and the frame 1 corresponding to a unit swing angle of the swing arm 41 (i.e., the rate of change of vertical distance) also changes with the drive unit 5. This difference in the rate of change of vertical distance results in different equivalent stiffness characteristics of the planetary rover's suspension under different positions. When the rate of change of vertical distance is large, the planetary rover's suspension exhibits a relatively "soft" characteristic; a small swing of the swing arm 41 can cause a large change in the relative height between the wheel 6 and the frame 1, which is beneficial for absorbing ground impacts. When the rate of change of vertical distance is small, the planetary rover's suspension exhibits a relatively "stiff" characteristic; the swing arm 41 needs a larger swing angle to cause a corresponding change in the relative height between the wheel 6 and the frame 1.

[0044] Furthermore, multiple drive units 5 can be controlled differently according to the terrain and requirements, thereby achieving differentiated control of multiple multi-link mechanisms 4 and assigning different vertical distance change rates to multiple wheels 6.

[0045] Thus, in the wheel-foot reconfigurable planetary rover of the present invention, the four-bar assembly 410, the two-bar assembly 420 of each multi-link mechanism 4 and the frame 1 together constitute a double closed-loop structure with two degrees of freedom. The drive unit 5 controls one of the two degrees of freedom (corresponding to the active degree of freedom), and controls the other of the two degrees of freedom (corresponding to the passive degree of freedom) by locking or unlocking the passive terrain adaptation mechanism 2 through the locking structure 3. When the locking structure 3 is unlocked, the passive terrain adaptation mechanism 2 transmits force among the multiple multi-link mechanisms 4, so that each multi-link mechanism 4 is linked to balance the ground load of each wheel 6, realize the passive adjustment function of the planetary rover's suspension, and ensure wheel-to-ground adhesion. By driving the double closed-loop structure to deform and adjust the position of the multi-link mechanism 4 through the drive unit 5, the active adjustment function of the planetary rover's suspension can be realized. Meanwhile, by controlling the two degrees of freedom, the planetary rover's suspension can achieve both a wheeled passive adaptive movement mode and a legged walking mode. The wheeled passive adaptive movement mode is suitable for flat or slightly undulating terrain, enabling the rover to quickly traverse flat terrain. The legged walking mode is suitable for complex and rugged terrain, allowing it to cross larger obstacles and ensuring its ability to navigate such terrain. Furthermore, the adoption of a double-closed-loop structure design, with multiple connection points between the multi-link mechanism 4 and the frame 1, provides more stable support for the multi-link mechanism 4 on the frame 1. Multiple force transmission paths between the multi-link mechanism 4 and the frame 1 enhance the stiffness and deformation resistance of the multi-link, making it better able to withstand ground impact loads transmitted by the wheels 6 and improving the fatigue life and reliability of the multi-link mechanism 4. Furthermore, the dual-closed-loop structure contains a pentagonal ring, and the equivalent length of the equivalent link 47 of the pentagonal ring changes with the position of the pentagonal ring. When the passive adjustment function of the planetary vehicle's suspension is activated, the vertical distance between the wheel 6 and the frame 1 changes at different rates when the drive unit 5 drives the dual-closed-loop structure to different positions. This gives the planetary vehicle's suspension different passive terrain adaptation characteristics, allowing for more flexible use of the planetary vehicle's passive adjustment function according to terrain needs, and providing more possibilities for the reconstruction of the planetary vehicle's suspension.

[0046] In summary, the reconfigurable suspension of the wheel-foot type planetary rover of this invention possesses reconfigurable characteristics, featuring passive terrain adaptation and active suspension adjustment functions. This facilitates meeting the diverse needs of the planetary rover when traversing different terrains. Through the control combination of two degrees of freedom, the planetary rover can achieve both wheeled passive adaptive movement and foot-walking modes, which enhances its rapid passage capability and mission execution efficiency in complex terrains, and helps reduce the overall energy consumption of planetary exploration missions in complex terrains. Furthermore, the dual closed-loop structure design increases the connection points and force transmission paths between the multi-link structure and the frame 1, improving the stiffness and load-bearing capacity of the planetary rover's suspension, and thus improving the fatigue life of the multi-link mechanism 4 and the reliability of the planetary rover. In addition, the variable-cell characteristics of the pentagonal ring allow the equivalent stiffness of the suspension to be reconfigured according to the pose of each multi-link mechanism 4, providing more possibilities for suspension reconfiguration and further enhancing the planetary rover's rapid passage capability and mission execution efficiency in complex terrains.

[0047] Optionally, the multi-link mechanism 4 includes a swing arm 41 and two adjacent set links. The swing arm 41 is provided with a first connecting part 401 for mounting the wheel 6. The multi-link mechanism 4 is configured to move to a singular point position where the transmission angle of the two set links is zero. The multi-link mechanism 4 is movably connected to the passive terrain adaptation mechanism 2 at a position outside the set links.

[0048] When two adjacent set links are collinear, the multi-link mechanism 4 is located at a singular point, where the transmission angle between these two set links is zero. In mechanical principles, in a multi-link closed loop, when the transmission angle between two adjacent set links is zero, links outside these two set links cannot drive them to rotate relative to each other. This position of the multi-link closed loop structure is called a singular point, also known as a dead point (but it can be removed from the dead point position, for example, through mechanical vibration).

[0049] The multi-link mechanism 4 is movably connected to the passive terrain adaptation mechanism 2 at a position other than the set link. For example, the multi-link mechanism 4 is provided with a fourth connecting part 404 for movably connecting to the passive terrain adaptation mechanism 2. The fourth connecting part 404 is located on a link other than the set link.

[0050] When the multi-link mechanism 4 moves to the singularity position, the rotational joint between the two set links can be understood as being restricted or locked. The double-closed-loop structure also transforms into a single-degree-of-freedom structure, retaining only one degree of freedom. The multi-link mechanism 4 is movably connected to the passive terrain adaptation mechanism 2 at a position outside the set links, so that the locking structure 3 can control this remaining degree of freedom. At this time, it is not necessary to rely on the drive unit 5 to lock one of the degrees of freedom of the double-closed-loop structure; the double-closed-loop structure can transform into a single-degree-of-freedom structure. This degree of freedom is used to provide a passive degree of freedom, thereby reducing the energy consumption requirement of the drive unit 5.

[0051] In some scenarios, drive unit 5 is used to control this degenerate degree of freedom, but not this residual degree of freedom. (See reference) Figure 2 As shown, two set links are, for example, the fourth link 45 and the fifth link 46, which form the second closed loop. The drive unit 5 is used to drive the second closed loop. The drive unit 5 is connected to the fifth link 46, for example. Whether the drive unit 5 outputs a position holding force or not, it does not affect this remaining degree of freedom, that is, it does not affect the passive degree of freedom. Therefore, when the locking structure 3 is unlocked, multiple multi-link mechanisms 4 can be linked to balance the ground load of each wheel 6, realizing the passive adjustment function of the planetary rover's suspension. For example, when the multi-link mechanism 4 moves to the singular point position, in the wheeled passive adaptive movement mode, the drive unit 5 can be in a follow-up condition, without outputting the relative position holding force of the two set links, and without forming an obstacle to the relative movement of the two set links. Or, for example, the drive unit 5 can output a small position holding force. In this scenario, the energy consumption of the planetary rover in, for example, the wheeled passive adaptive movement mode can be reduced.

[0052] In other scenarios, the drive unit 5 can control this residual degree of freedom. For example, two links set as the second closed loop, such as the fourth link 45 and the fifth link 46, are used by the drive unit 5 to drive the relative rotation of the second link 43 and the third link 44. That is, one of the second link 43 and the third link 44 is the active link. If the drive unit 5 controls this residual degree of freedom, the passive terrain adaptation mechanism 2 cannot work. If the drive unit 5 does not control this residual degree of freedom and does not restrict it, the passive terrain adaptation mechanism 2 can work normally. For example, the drive unit 5 can be in a follow-up mode. Follow-up means that it does not affect the relative rotation of the second link 43 and the third link 44. For example, the drive unit 5 includes a drive motor, the housing of which is connected to the second link 43, and the output shaft is fixedly connected to the third link 44. When the drive unit 5 is in follow-up mode, the drive motor can be de-energized, and the rotor of the drive motor can rotate with the output shaft and the active link. In another exemplary embodiment, the drive unit 5 can be connected to the active linkage via a second clutch, and the force transmission path between the drive unit 5 and the active linkage, such as the third linkage 44, can be disconnected via the second clutch. Thus, when the locking structure 3 is unlocked, the terrain excitation received by the wheel 6 can still be transmitted to the passive terrain adaptation mechanism 2, or the force transmitted by the passive terrain adaptation mechanism 2 can be transmitted to the ground. This ensures that the passive terrain adaptation mechanism 2 reliably transmits force among the multiple multi-link mechanisms 4, achieving a balanced distribution of the ground load on each wheel 6.

[0053] Thus, when the double-closed-loop structure moves to the singularity position, the transmission angle between the two collinear set links is zero. At this singularity position, there is no need to rely on the drive unit 5 to lock one of the degrees of freedom of the double-closed-loop structure. The double-closed-loop structure can be transformed into a single-degree-of-freedom structure. Its remaining degree of freedom can provide the aforementioned passive degree of freedom. Since the two adjacent set links are links other than the swing arm 41, the rotation of the swing arm 41 caused by the terrain excitation of the wheel 6 can be transformed into the deformation motion of the double-closed-loop structure. Correspondingly, since the multi-link mechanism 4 is movably connected to the passive terrain adaptation mechanism 2 at a position other than the set links, the driving force transmitted by the passive terrain adaptation mechanism 2 can be transformed into the deformation motion of the double-closed-loop structure. Utilizing this characteristic, when the planetary rover is in the passive adaptive movement mode and the double-closed-loop structure moves to the singularity position, there is no need to lock one of the two degrees of freedom through the drive unit 5, thereby reducing the energy consumption of the planetary rover.

[0054] like Figures 1 to 5 As shown, the main reference is... Figure 1Optionally, the four-bar linkage 410 includes the swing arm 41, and the swing arm 41 is further provided with a second connecting part 402. The second connecting part 402 is rotatably connected to the frame 1 at the end position of the frame 1 in the front-rear direction. The axis of the two-bar linkage 420 rotatably connected to the frame 1 is arranged parallel to the axis of the second connecting part 402.

[0055] The end position of the frame 1 in the longitudinal direction refers to the end region of the frame 1 in the longitudinal direction (i.e., the direction in which the planetary vehicle moves forward and backward, corresponding to the X-axis direction). Specifically, the second connecting part 402 is arranged at the longitudinal end position of the frame 1, that is, at the very front or rear end of the frame 1. This end position arrangement makes the connection point between the swing arm 41 and the frame 1 as far away from the longitudinal center of the frame 1 as possible, which is beneficial for the front and rear wheels 6 to obtain a larger span.

[0056] In the two-link assembly 420, the fifth link 46 is rotatably connected to the frame 1, and the axis of their rotatable connection is parallel to the axis of the second connecting part 402. Specifically, the two axes are spaced apart in the front-rear direction.

[0057] Thus, the second connecting part 402 is arranged at the longitudinal end of the frame 1, so that the connection point between the swing arm 41 and the frame 1 is as far away from the longitudinal center of the frame 1 as possible. This helps to increase the span between the front and rear wheels 6, improve the vehicle's driving stability in the longitudinal direction (i.e., longitudinal direction), and reduce the variation in the pitch angle of the frame 1. At the same time, the axis of rotational connection between the two-link assembly 420 and the frame 1 is parallel to the axis of the second connecting part 402. The second connecting part 402 is located at the end of the frame 1 in the longitudinal direction, and the connection point between the two-link assembly 420 and the frame 1 is relatively inward in the longitudinal direction. The two form a certain span in the longitudinal direction, so that the ground impact load from the wheels 6 can be distributed and transmitted to the frame 1 through two relatively far connection points. This helps to improve the reliability of the frame 1 and the motion stability and reliability of the multi-link mechanism 4.

[0058] like Figure 1 and Figure 6 As shown, optionally, the two set links correspond to the two sides of the second closed loop respectively, the drive unit 5 is driven and connected to the second closed loop, and the multi-link mechanism 4 is provided with a fourth connecting part 404 outside the second closed loop and the swing arm 41. The fourth connecting part 404 is used to be movably connected to the passive terrain adaptation mechanism 2.

[0059] Specifically, as described above, the connecting rod and the swing arm 41 are set to be different connecting rods, such as... Figure 5 As shown, the two set links can be the fourth link 45 and the fifth link 46, respectively. Figure 4As shown, the two set links can be the fourth link 45 and the fifth link 46, or the third link 44 and the fourth link 45.

[0060] like Figures 1 to 4 As shown, the first closed loop and the second closed loop may share one or more links. In some scenarios, the links shared by the first closed loop and the second closed loop may include a swing arm 41, while in other scenarios, the links shared by the first closed loop and the second closed loop may not include a swing arm 41.

[0061] The fourth connecting part 404 can be in the form of a ball joint, a fisheye bearing seat, or a lug-type hinge hole, etc., to achieve a ball joint connection with the passive terrain adaptation mechanism 2.

[0062] This design facilitates a shorter force transmission path between the drive unit 5 and the set linkage, improving drive efficiency and control response speed. Simultaneously, the fourth connecting part 404 avoids the second closed loop and the swing arm 41, facilitating its placement and connection with the passive terrain adaptation mechanism 2. It also prevents the force of the passive terrain adaptation mechanism 2 from directly superimposing on the linkage where the fourth connecting part 404 is located. The force of the passive terrain adaptation mechanism 2 must be transmitted through other linkages to affect the second closed loop driven by the drive unit 5, objectively lengthening the force transmission path of the interference force and reducing the possibility of interference between active control motion and passive terrain adaptation motion. This improves the motion stability and reliability of the multi-link mechanism 4.

[0063] like Figures 1 to 5 As shown, in the four-bar linkage 410, the three links other than the swing arm 41 are a first link 42, a second link 43, and a third link 44 that are rotatably connected in sequence. The first link 42 is rotatably connected to the swing arm 41 at a position spaced apart from the second link 43, and the third link 44 has a third connecting part 403 at a position spaced apart from the second link 43. The two links of the two-bar linkage 420 are a fourth link 45 and a fifth link 46 that are rotatably connected, and the fifth link 46 is rotatably connected to the frame 1 at the end away from the fourth link 45. The configuration of the first closed loop and the second closed loop will be explained next based on this.

[0064] Optionally, the third connecting part 403 is rotatably connected to the frame 1 and coaxially arranged with the second connecting part 402, and the fourth link 45 is rotatably connected to either the first link 42 or the second link 43 at the end away from the fifth link 46.

[0065] like Figure 1 , Figure 2 , Figure 5 and Figure 6 As shown, the fourth link 45 is rotatably connected to the first link 42 at the end away from the fifth link 46. In this case, the first closed loop is a quadrilateral loop, the second closed loop is a pentagonal loop, and the two set links can be the fourth link 45 and the fifth link 46 respectively. The fourth connecting part 404 and the driving unit 5 are drivenly connected to the fifth link 46. The fourth connecting part 404 can be provided on the second link 43.

[0066] At this time, when the drive unit 5 drives the second closed loop to deform, the shape of the second closed loop changes. This can drive the second link 43 to move, thereby realizing the movement of the four-bar linkage 410, and thus realizing the deformation movement of the entire double closed-loop structure. When the fourth link 45 and the fifth link 46 are collinear, one degree of freedom of the second closed loop is restricted, and the double closed-loop structure degenerates into a single-degree-of-freedom structure. There is no need for the drive unit 5 to lock the fifth link 46 to restrict the corresponding degree of freedom, and a passive adaptive movement mode, such as a wheel, can also be realized.

[0067] Accordingly, if the fourth link 45 is rotatably connected to the second link 43 at the end away from the fifth link 46, the fourth connecting part 404 can be provided on the first link 42.

[0068] Optionally, the third connecting part 403 is rotatably connected to the frame 1 and spaced apart from the second connecting part 402, and the fourth link 45 is rotatably connected at the end away from the fifth link 46 to any one of the first link 42, the second link 43 and the third link 44.

[0069] like Figure 3 As shown, the fourth link 45 is connected to the first link 42 at the end furthest from the fifth link 46. In this case, both the first and second closed loops are pentagonal rings, sharing three sides. The fourth connecting part 404 can be disposed on the second link 43.

[0070] like Figure 4 As shown, this illustrates the case where the fourth link 45 is connected to the third link 44 at the end furthest from the fifth link 46. In this case, the first closed loop is a pentagonal loop, and the second closed loop is a quadrilateral loop. The two connecting links can be the fourth link 45 and the fifth link 46, or the third link 44 and the fourth link 45, respectively. The drive unit 5 is driven by the fifth link 46, and the fourth connecting part 404 can be disposed on the first link 42 or the second link 43. When the fourth link 45 and the fifth link 46 are collinear, one degree of freedom of the second closed loop is restricted, and the double-closed-loop structure degenerates into a single-degree-of-freedom structure. The drive unit 5 cannot control the remaining degree of freedom, thus eliminating the need for the drive unit 5 to output power, thereby achieving a wheeled passive adaptive movement mode.

[0071] Optionally, the drive unit 5 is mounted on the frame 1, and the output end of the drive unit 5 is connected to one of the two links of the two-bar linkage 420 that is rotatably connected to the frame 1.

[0072] That is, the drive unit 5 is driven to the fifth link 46. The explanation of this part has been described above and will not be repeated here.

[0073] This configuration avoids the drive unit 5 from swinging with one of the links of the multi-link mechanism 4, reduces the motion inertia of the multi-link mechanism 4, and helps to improve the dynamic response speed and sensitivity of the multi-link mechanism 4.

[0074] like Figures 5 to 7 As shown, optionally, both of the setting links are provided with angle limiting blocks 405, and the abutment of the two angle limiting blocks 405 restricts the limit angle of relative rotation of the two setting links.

[0075] The corner limit block 405 can be set to one or more sets. Figure 5 The diagram illustrates a case with one set of limiting angles of relative rotation of the two set links in one direction. It can be configured with two sets, where the limiting angles of relative rotation of the two set links in another direction are limited by the abutment of two angular limiters in the other set.

[0076] This helps ensure that the two set links move within the designed safe working range, avoiding interference, jamming, or even structural damage to the multi-link mechanism 4 caused by control errors, unexpected external forces, or abnormal movement leading to the relative rotation of the two set links exceeding the design range. This improves the reliability and safety of the multi-link mechanism 4's movement.

[0077] like Figure 1 As shown, optionally, the swing arm 41 includes a first segment 411 and a second segment 412; the lower end of the first segment 411 is rotatably connected to the frame 1, the upper end of the first segment 411 is rotatably connected to the first connecting rod 42, the upper end of the second segment 412 is fixedly connected to the lower end of the first segment 411, the second segment 412 is inclined relative to the first segment 411, and from top to bottom, the distance from a point on the second segment 412 to the center of the frame 1 gradually increases in the front-rear direction, and the lower end of the second segment 412 is provided with the first connecting part 401.

[0078] Here, the upper end of the second segment 412 is fixedly connected to the lower end of the first segment 411, meaning that the two do not rotate relative to each other. In some scenarios, the two are connected as a single unit, such as... Figure 5 and Figure 6As shown, in other scenarios, the two are detachably connected. For example, the first link segment 411 and the second link segment 412 are fixedly connected together by a common pivot, and this common pivot is rotatably connected to the frame 1 and the third link 44 respectively.

[0079] The tilt angle of the second segment 412 can be adjusted according to actual design requirements. Its tilt direction and tilt angle should ensure that the lower end of the second segment 412 extends appropriately in the front-rear direction to optimize the position of the wheel 6 in the front-rear direction and increase the wheel track between the front and rear wheels 6.

[0080] Optionally, the drive unit 5 includes a drive motor and a brake mechanism. The housing of the drive motor is mounted on the frame 1. The output shaft of the drive motor is connected to the rotating shaft of the fifth link 46. The brake mechanism is used to lock the rotating shaft of the fifth link 46 by means of a brake.

[0081] The brake mechanism can take the form of an electromagnetic brake, friction clutch, mechanical locking pin, or ratchet and pawl mechanism. The brake mechanism can be mounted on the output shaft of the drive motor. When engaged, it directly locks the output shaft of the drive motor, thereby indirectly locking the shaft of the fifth link 46. Alternatively, the brake mechanism can be directly mounted on the shaft of the fifth link 46, directly locking the rotation of that shaft. The control method of the brake mechanism can be energized and de-energized, or energized and de-energized (i.e., normally closed brake), depending on safety requirements.

[0082] Thus, when necessary, such as when the double closed-loop structure is not located at a singular point, the shaft of the fifth link 46 can be locked by the brake mechanism, which helps to protect the internal components of the drive motor and avoids relying on the drive motor to output holding torque to lock the position of the fifth link 46.

[0083] like Figure 1 and Figure 5 As shown, optionally, the number of multi-link mechanisms 4 is four, and the four multi-link mechanisms 4 are respectively arranged in the four corner areas of the frame 1; when the locking structure 3 is unlocked, the passive terrain adaptation mechanism 2 is configured to: cause the two multi-link mechanisms 4 located in each pair of diagonally opposite areas of the frame 1 to be linked and cause the vertical distance between the corresponding two wheels 6 and the frame 1 to increase or decrease simultaneously; cause the two multi-link mechanisms 4 located in each pair of adjacent corner areas of the frame 1 to be linked and cause the vertical distance between the corresponding two wheels 6 and the frame 1 to increase and decrease respectively.

[0084] The projection of the planetary rover's frame 1 onto the horizontal ground is rectangular, with the four corner areas corresponding to the front left, front right, rear left, and rear right corner areas, respectively. The swing arms 41 of the four multi-link mechanisms 4 are rotatably connected to these four corner areas of the frame 1 in a one-to-one correspondence. Each swing arm 41 has a first connecting part 401 at its lower end, through which the wheels 6 are mounted.

[0085] The passive terrain adaptation mechanism 2 is simultaneously connected to four multi-link mechanisms 4, and its linkage state is controlled by a locking structure 3. When the locking structure 3 is unlocked, the passive terrain adaptation mechanism 2 is in a free-moving state and can transmit forces between the four multi-link mechanisms 4. This enables the four multi-link mechanisms 4 to move in unison, ultimately manifested as the motion correlation of the left front wheel 6, right front wheel 6, left rear wheel 6, and right rear wheel 6.

[0086] Two multi-link mechanisms 4 located in each pair of diagonally opposite areas of the frame 1 are configured to be linked. For example, the multi-link mechanism 4 in the left front corner area (corresponding to the left front wheel 6) is linked with the multi-link mechanism 4 in the right rear corner area (corresponding to the right rear wheel 6), causing the vertical distance between the left front wheel 6 and the right rear wheel 6 relative to the frame 1 to increase or decrease simultaneously. Similarly, the multi-link mechanism 4 in the right front corner area (corresponding to the right front wheel 6) is linked with the multi-link mechanism 4 in the left rear corner area (corresponding to the left rear wheel 6), causing the vertical distance between the right front wheel 6 and the left rear wheel 6 relative to the frame 1 to increase or decrease simultaneously. Two multi-link mechanisms 4 located in each pair of adjacent corner areas of the frame 1 are configured to be linked in opposite directions. For example, the two multi-link mechanisms 4 on the left (corresponding to the front left wheel 6 and the rear left wheel 6) are linked, causing the vertical distance between the front left wheel 6 and the rear left wheel 6 relative to the frame 1 to increase and decrease respectively (i.e., relative to the horizontal ground, one rises while the other falls). Similarly, the two multi-link mechanisms 4 on the right (corresponding to the front right wheel 6 and the rear right wheel 6) are linked, causing the vertical distance between the front right wheel 6 and the rear right wheel 6 relative to the frame 1 to increase and decrease respectively.

[0087] Taking the planetary vehicle traveling on a level ground in a wheeled passive adaptive movement mode as an example, when the left front wheel 6 encounters an obstacle, the left front wheel 6 is lifted up by the ground reaction force. In the traditional way, due to the lack of a linkage mechanism in the suspension, the lifting of the left front wheel 6 directly causes the left front corner area of ​​the frame 1 to be lifted as well. The lifting range is basically the same as the height of the obstacle, while the height of the other three corner areas remains basically unchanged. At this time, the frame 1 produces a large pitch and roll.

[0088] In this invention, the left front corner wheel 6 is lifted upwards by the ground reaction force, reducing the vertical distance between the left front corner wheel 6 and the frame 1. Under the force transmission of the passive terrain adaptation mechanism 2, the four multi-link mechanisms 4 work together, causing the vertical distance between the right rear corner wheel 6 and the frame 1 to decrease, the vertical distance between the left rear corner wheel 6 and the frame 1 to increase, and the vertical distance between the right front corner wheel 6 and the frame 1 to increase. At this time, the height change of the four corner areas of the frame 1 is no longer the traditional "one corner rises, the other three remain still" distribution, but rather a "three-corner rises, one corner falls": the left front corner area, the left rear corner area, and the right front corner area of ​​the frame 1 rise, while the right rear corner area of ​​the frame 1 falls. Specifically, after the left front corner wheel 6 is lifted by the obstacle, the left front corner area of ​​the frame 1 rises directly, with the rise being less than the height of the obstacle. Simultaneously, as the vertical distance between the left rear wheel 6 and the frame 1 increases (i.e., the left rear wheel 6 moves downward relative to the frame 1), the left rear corner area of ​​the frame 1 is lifted and raised. Similarly, as the vertical distance between the right front wheel 6 and the frame 1 increases (i.e., the right front wheel 6 moves downward relative to the frame 1), the right front corner area of ​​the frame 1 is also lifted and raised. Conversely, as the vertical distance between the right rear wheel 6 and the frame 1 decreases (i.e., the right rear wheel 6 moves upward relative to the frame 1), the right rear corner area of ​​the frame 1 actually lowers.

[0089] The elevation of the left rear corner and right front corner of the frame 1 helps to offset the effects of the elevation of the left front corner on the pitch in the front-rear direction and the lateral tilt in the left-right direction. The overall tilt of the frame 1 is much smaller than that of the traditional method, and the frame 1 can maintain a more level posture to pass through obstacles. At the same time, the linkage mechanism transfers the extra load generated by the left front corner wheel 6 due to the encounter with the obstacle to, for example, the left rear corner wheel 6 and the right front corner wheel 6 through the passive terrain adaptation mechanism 2. This avoids the situation where the left front corner wheel 6 bears too large a load alone, so that the load distribution of the four wheels 6 is more dispersed and even, thereby effectively avoiding the phenomenon of load concentration. Furthermore, when the driving conditions of the drive unit 5 are met, such as when the height of the obstacle reaches a set threshold, and the wheel 6 at the left front corner contacts the obstacle and is lifted, the position of the wheel 6 can be actively adjusted by the drive unit 5. For example, the drive unit 5 can drive the corresponding multi-link mechanism 4 to reduce the vertical distance between the wheel 6 at the left front corner and the frame 1, thereby reducing the passive lifting height requirement of the wheel 6, reducing the pitch and roll amplitude of the frame 1, and reducing the passive linkage amplitude of the multiple multi-link mechanisms 4.

[0090] Similarly, when the left front wheel 6 encounters a pothole, and loses ground support, the four multi-link mechanisms 4 work together under the force transmission of the passive terrain adaptation mechanism 2. This helps to increase the vertical distance between the left front wheel 6 and the frame 1, thereby allowing the left front wheel 6 to contact the ground. This helps the left front wheel 6 overcome the instability caused by the terrain depression, maintain effective contact with the ground, maintain traction, and prevent the wheel 6 from being suspended in the air.

[0091] In this way, the four multi-link mechanisms 4 are linked together through the passive terrain adaptation mechanism 2, which can not only ensure the wheel-to-ground adhesion of the four wheels 6, but also improve the anti-pitch and anti-roll performance of the frame 1, enhance the driving stability of the planetary rover, and help protect the scientific instruments and equipment carried on the planetary rover.

[0092] like Figure 1 and Figures 5 to 7 As shown, optionally, the passive terrain adaptation mechanism 2 includes a balance bar 21 and four force transmission components 22; the balance bar 21 is arranged in the left-right direction and is rotatably connected to the vehicle frame 1 about the vertical axis at the middle position in the left-right direction; the four force transmission components 22 are arranged one-to-one with the four multi-link mechanisms 4, and two force transmission components 22 are movably connected to both ends of the balance bar 21 in the left-right direction, and the force transmission component 22 is movably connected to the corresponding multi-link mechanism 4 at the end away from the balance bar 21.

[0093] The stabilizer bar 21 is a component that extends horizontally (i.e., laterally) along the left-right direction of the planetary rover. The stabilizer bar 21 is rotatably connected to the frame 1 about a vertical axis at or near the midpoint of its length. For example, the stabilizer bar 21 has a vertical mounting hole at the midpoint of its left-right direction, and a vertical mounting shaft 71 passes through the vertical mounting hole and is fixedly connected to the stabilizer bar 21. The vertical mounting shaft 71 is rotatably connected to the frame 1 at the center of the frame 1, thus realizing the rotatable connection between the stabilizer bar 21 and the frame 1 about a vertical axis.

[0094] Two force transmission components 22 are movably connected to the left end of the balance bar 21, corresponding to the two multi-link mechanisms 4 on the left side. Similarly, two force transmission components 22 are movably connected to the right end of the balance bar 21, corresponding to the two multi-link mechanisms 4 on the right side. One end of each force transmission component 22 is hinged to the end of the balance bar 21, and the other end is movably connected to the fourth connecting part 404 of the corresponding multi-link mechanism 4. The force transmission component 22 can be in the form of a link, etc., and both ends can be connected by ball joints to accommodate multi-directional spatial movement requirements and prevent virtual constraints at both ends of the force transmission component 22 from affecting the movement of the passive terrain adaptation mechanism 2 when multiple multi-link mechanisms 4 are linked.

[0095] When the locking structure 3 is unlocked, the balance bar 21 can rotate freely around the vertical axis, and the four force transmission components 22 move accordingly, transmitting push and pull forces between the balance bar 21 and the four multi-link mechanisms 4, causing the four multi-link mechanisms 4 to move in unison. When the locking structure 3 locks any one of the five components—the balance bar 21 and the four force transmission components 22—the other components cannot move, and the linkage of the four multi-link mechanisms 4 is released. For example, the locking structure 3 is used to lock or unlock the rotation of the balance bar 21 relative to the frame 1.

[0096] Thus, since the balance bar 21 is rotatably connected to the frame 1 around the vertical axis in the middle position, the rotation of the balance bar 21 can realize the linkage of the four force transmission components 22. The passive terrain adaptation mechanism 2 has a simple structure and strong practicality.

[0097] like Figure 5 and Figure 7 As shown, optionally, the locking structure 3 includes a first clutch 31, which is disposed at the connection between the stabilizer bar 21 and the frame 1, for locking or unlocking the rotation of the stabilizer bar 21 relative to the frame 1.

[0098] like Figure 7 As shown, exemplarily, the first clutch 31 is arranged at the vertical mounting shaft 71. The movable part of the first clutch 31 is fixedly connected to the vertical mounting shaft 71, and the fixed part of the first clutch 31 is fixedly connected to the frame 1. The first clutch 31 can be in the form of an electromagnetic clutch or a mechanical friction clutch, etc. When the first clutch 31 is energized or receives a control signal, its internal friction plates or teeth engage, causing the stabilizer bar 21 to lock relative to the frame 1. The stabilizer bar 21 cannot rotate around the vertical axis, and the linkage function of the passive terrain adaptation mechanism 2 is released. When the first clutch 31 is de-energized or the control signal is withdrawn, its internal engagement disengages, and the stabilizer bar 21 returns to a rotatable state.

[0099] Thus, the first clutch 31 is located at the rotational connection between the stabilizer bar 21 and the frame 1, which can directly control the rotational freedom of the stabilizer bar 21, the core linkage element of the passive terrain adaptation mechanism 2. This makes the locking and unlocking actions of the passive terrain adaptation mechanism 2 more direct and reliable, which is conducive to improving the stability and durability of the passive terrain adaptation mechanism 2 and even the entire planetary vehicle in long-term operation. In addition, the arrangement of the first clutch 31 and the stabilizer bar 21 is relatively compact, and avoids the planetary vehicle from being unbalanced due to the arrangement of the first clutch 31. This is conducive to maintaining the center of gravity balance of the planetary vehicle during driving, thereby improving the driving stability and handling of the planetary vehicle.

[0100] While the present invention has been disclosed above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and all such changes and modifications will fall within the scope of protection of the present invention.

Claims

1. A wheel-footed reconfigurable planetary rover, characterized in that, The system includes a frame (1), a passive terrain adaptation mechanism (2), a locking structure (3), multiple multi-link mechanisms (4), multiple drive units (5), and multiple wheels (6); each of the multi-link mechanisms (4) includes a four-bar assembly (410) and a two-bar assembly (420); the four-bar assembly (410) is rotatably connected to the frame (1) and forms a first closed loop; the two ends of the two-bar assembly (420) are rotatably connected to the four-bar assembly (410) and the frame (1) respectively, and form a second closed loop; the first The closed loop and the second closed loop together constitute a double closed loop structure with two degrees of freedom, and one of them has a pentagonal ring; the driving unit (5) is driven and connected to the multi-link mechanism (4) and controls one of the two degrees of freedom. When the driving unit (5) controls the corresponding degree of freedom to lock, the double closed loop structure becomes a single degree of freedom structure. The length of the equivalent rod (47) of the equivalent four-link of the pentagonal ring changes with the pose of the pentagonal ring; the lower end of the multi-link mechanism (4) is equipped with the wheel (6). The passive terrain adaptation mechanism (2) is movably connected to the vehicle frame (1) and the multiple multi-link mechanisms (4). The passive terrain adaptation mechanism (2) is equipped with the locking structure (3). The locking or unlocking of the locking structure (3) controls the other of the two degrees of freedom. When the locking structure (3) is unlocked, the passive terrain adaptation mechanism (2) and the multiple multi-link mechanisms (4) work together to balance the ground load of each wheel (6).

2. The wheel-footed reconfigurable planetary rover according to claim 1, characterized in that, The multi-link mechanism (4) includes a swing arm (41) and two adjacent set links. The swing arm (41) is provided with a first connecting part (401) for mounting the wheel (6). The multi-link mechanism (4) is configured to move to a singular point position where the transmission angle of the two set links is zero. The multi-link mechanism (4) is movably connected to the passive terrain adaptation mechanism (2) at a position outside the set links.

3. The wheel-footed reconfigurable planetary rover according to claim 2, characterized in that, The four-bar linkage (410) includes the swing arm (41), and the swing arm (41) is further provided with a second connecting part (402). The second connecting part (402) is rotatably connected to the frame (1) at the end position of the frame (1) in the front-rear direction. The axis of the two-bar linkage (420) rotatably connected to the frame (1) is arranged parallel to the axis of the second connecting part (402).

4. The wheel-footed reconfigurable planetary rover according to claim 3, characterized in that, The two set links correspond to the two sides of the second closed loop respectively. The drive unit (5) is driven and connected to the second closed loop. The multi-link mechanism (4) is provided with a fourth connecting part (404) outside the second closed loop and the swing arm (41). The fourth connecting part (404) is used to be movably connected to the passive terrain adaptation mechanism (2).

5. The wheel-footed reconfigurable planetary rover according to claim 4, characterized in that, In the four-bar linkage (410), the three links other than the swing arm (41) are a first link (42), a second link (43), and a third link (44) that are rotatably connected in sequence; the first link (42) is rotatably connected to the swing arm (41) at a position spaced apart from the second link (43), and the third link (44) is provided with a third connecting part (403) at a position spaced apart from the second link (43); the two links of the two-bar linkage (420) are a fourth link (45) and a fifth link (46) that are rotatably connected, and the fifth link (46) is rotatably connected to the frame (1) at the end away from the fourth link (45); The third connecting part (403) is rotatably connected to the frame (1) and coaxially arranged with the second connecting part (402). The fourth link (45) is rotatably connected to either the first link (42) or the second link (43) at the end away from the fifth link (46). Alternatively, the third connecting part (403) is rotatably connected to the frame (1) and spaced apart from the second connecting part (402), and the fourth link (45) is rotatably connected at the end away from the fifth link (46) to any one of the first link (42), the second link (43) and the third link (44).

6. The wheel-footed reconfigurable planetary rover according to claim 2, characterized in that, The drive unit (5) is mounted on the frame (1), and the output end of the drive unit (5) is connected to one of the two links of the two-bar linkage (420) that is rotatably connected to the frame (1).

7. The wheel-footed reconfigurable planetary rover according to claim 5, characterized in that, Both of the aforementioned setting links are provided with angle limiting blocks (405), and the abutment of the two angle limiting blocks (405) restricts the limit angle of relative rotation of the two setting links; And / or, the swing arm (41) includes a first segment (411) and a second segment (412); the lower end of the first segment (411) is rotatably connected to the frame (1), the upper end of the first segment (411) is rotatably connected to the first connecting rod (42), the upper end of the second segment (412) is fixedly connected to the lower end of the first segment (411), the second segment (412) is inclined relative to the first segment (411), and from top to bottom, the distance from the point on the second segment (412) to the center of the frame (1) gradually increases in the front-rear direction, and the lower end of the second segment (412) is provided with the first connecting part (401).

8. The wheel-footed reconfigurable planetary rover according to claim 1, characterized in that, The number of the multi-link mechanisms (4) is four, and the four multi-link mechanisms (4) are respectively arranged in the four corner areas of the frame (1); when the locking structure (3) is unlocked, the passive terrain adaptation mechanism (2) is configured to: cause the two multi-link mechanisms (4) located in each pair of diagonal areas of the frame (1) to be linked and cause the vertical distance between the corresponding two wheels (6) and the frame (1) to increase or decrease simultaneously; cause the two multi-link mechanisms (4) located in each pair of adjacent corner areas of the frame (1) to be linked and cause the vertical distance between the corresponding two wheels (6) and the frame (1) to increase and decrease respectively.

9. The wheel-footed reconfigurable planetary rover according to claim 8, characterized in that, The passive terrain adaptation mechanism (2) includes a balance bar (21) and four force transmission components (22); the balance bar (21) is arranged in the left-right direction and is rotatably connected to the vehicle frame (1) about the vertical axis at the middle position in the left-right direction; the four force transmission components (22) are arranged one-to-one with the four multi-link mechanisms (4), and two force transmission components (22) are movably connected to both ends of the balance bar (21) in the left-right direction, and the force transmission component (22) is movably connected to the corresponding multi-link mechanism (4) at the end away from the balance bar (21); The locking structure (3) includes a first clutch (31), which is located at the connection between the balance bar (21) and the frame (1) and is used to lock or unlock the rotation of the balance bar (21) relative to the frame (1).

10. The wheel-footed reconfigurable planetary rover according to claim 1, characterized in that, The wheel-foot reconfigurable planetary vehicle has a wheeled passive adaptive mobility mode, a foot walking mode, and an active-passive composite mobility mode. In the wheeled passive adaptive movement mode, one of the two degrees of freedom of the double closed-loop structure is restricted and the double closed-loop structure is transformed into a single degree of freedom structure. The passive terrain adaptation mechanism (2) is unlocked by the locking structure (3). The passive terrain adaptation mechanism (2) transmits force between multiple multi-link mechanisms (4), so that each multi-link mechanism (4) links together to balance the ground load of each wheel (6). In the foot-walking mode, the passive terrain adaptation mechanism (2) is locked by the locking structure (3), and each of the multi-link mechanisms (4) is independently controlled by the corresponding drive unit (5). By controlling the coordinated action of multiple multi-link mechanisms (4), the multiple wheels (6) are alternately lifted and landed to achieve foot-walking. In the active-passive composite movement mode, the drive unit (5) works to drive the multi-link mechanism (4) to move, the passive terrain adaptation mechanism (2) is unlocked by the locking structure (3), and the passive terrain adaptation mechanism (2) transmits force among the multiple multi-link mechanisms (4).

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