A multi-posture metamorphic vehicle based on a four-degree-of-freedom parallel mechanism

Abstract

The present application relates to a kind of multi-posture metamorphic car based on four degrees of freedom parallel mechanism, including 3R1T parallel mechanism, wheel-foot mechanism, machine body frame and detection device, four 3R1T parallel mechanisms are provided, distributed in the four corners of machine body frame, the lower end of 3R1T parallel mechanism is connected with wheel-foot mechanism, wheel-foot mechanism is used to realize the walking of metamorphic car, detection device is arranged in four directions of machine body frame;3R1T parallel mechanism includes static platform, dynamic platform and four branch kinematic chains between two platforms, first branch kinematic chain and third branch kinematic chain are oppositely arranged, second branch kinematic chain and fourth branch kinematic chain are oppositely arranged;Motion chain driving mechanism is arranged between each branch kinematic chain and static platform, for controlling the action of rotary pair connected with static platform in branch kinematic chain.The present application utilizes metamorphic parallel mechanism to cooperate wheel-foot structure to realize the multi-posture adjustment of metamorphic car, to improve the flexibility of car body movement;It has multiple motion modes simultaneously, and application occasion is very extensive.

Description

Technical Field

[0001] This invention belongs to the technical field of ground transportation vehicles and robots, specifically relating to a multi-posture variable cell vehicle based on a four-degree-of-freedom parallel mechanism. Background Technology

[0002] Robotics and their actuator technologies, as a strategic high technology, have attracted widespread attention from scholars, enterprises and institutions at home and abroad. The research and application of new mobile robots and related technologies are of great significance to promoting social progress, economic development and improving people's quality of life.

[0003] Traditional ground mobile robots are mainly classified into four types according to their structural form: wheeled, tracked, legged, and hybrid (wheel-tracked, wheel-legged, legged-tracked, and wheel-tracked-legged). Among them, wheeled structures have relatively high speed and are easy to control in structured road environments, but their obstacle-crossing ability is weak; tracked structures have strong obstacle-crossing ability in both structured and unstructured road environments, but they consume more energy; legged structures are flexible and show unparalleled superiority in terrain adaptability, however, their structure is usually more complex, their walking speed is relatively slow, with a maximum speed of only 11 km / h, and their flat feet support them when landing, resulting in very high friction, which can cause mechanical damage.

[0004] It is evident that ground mobile robots with only a single driving (walking) function are insufficient to meet the requirements of various road conditions. Therefore, composite mobile robots have become a hot topic in the field of robotics research. Among them, variable-cell components, due to their ability to change the structure and number of components, are increasingly being applied in the field of composite robots.

[0005] Modular vehicles are a type of transportation with broad road adaptability, capable of adapting to various complex road surfaces through transformation. They possess multiple movement modes, have a wide range of applications, strong load capacity, and are primarily used in situations where working surfaces are mostly rugged and obstructed, demonstrating excellent environmental adaptability. They also have high practical value in fields such as unmanned combat, disaster relief, material transportation, and resource exploration.

[0006] However, existing modular vehicles and related derivative mechanisms have shortcomings in function and design, including limited movement modes, low degree of freedom, and difficulty in meeting the usage needs of different road conditions and working conditions. Summary of the Invention

[0007] The purpose of this invention is to provide a multi-posture variable cell vehicle based on a four-degree-of-freedom parallel mechanism to solve the problems of general variable cell vehicles, such as single posture, few degrees of freedom in motion mode, small range of motion, and difficulty in operation.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is: a multi-posture variable cell vehicle based on a four-degree-of-freedom parallel mechanism, including a 3R1T parallel mechanism, a wheel-foot mechanism, a body frame, and a detection device. Four 3R1T parallel mechanisms are provided and distributed at the four corners of the body frame. The lower end of the 3R1T parallel mechanism is connected to the wheel-foot mechanism, which is used to realize the movement of the variable cell vehicle. The detection device is arranged in four directions of the body frame. The 3R1T parallel mechanism includes a static platform, a moving platform, and four branch kinematic chains between the two platforms. The first and third branch kinematic chains are arranged opposite each other in a first direction between the two platforms, and the second and fourth branch kinematic chains are arranged opposite each other in a second direction between the two platforms. The first direction is perpendicular to the second direction. The first branch kinematic chain includes a first link and a second link, which are connected by a second revolute joint. The first link is connected to the stationary platform through the first revolute joint, and the second link is connected to one end of the third link through a first universal joint. The second branch kinematic chain includes a fourth link, a fifth link, and a sixth link. The fourth link and the fifth link are connected by a fourth revolute joint. The fourth link is connected to the stationary platform by a third revolute joint. The fifth link is connected to one end of the sixth link by a second universal joint. The third branch kinematic chain includes the seventh link and the eighth link. The seventh link and the eighth link are connected by the sixth revolute joint. The seventh link is connected to the stationary platform by the fifth revolute joint. The eighth link is connected to the other end of the third link by the third universal joint. The fourth branch kinematic chain includes the ninth link, the tenth link, and the eleventh link. The three links are connected in sequence through the eighth and ninth revolute joints. The ninth link is connected to the stationary platform through the seventh revolute joint, and the eleventh link is connected to the moving platform through a spherical joint. The moving platform is fixed on the fixed frame of the wheel-foot mechanism. The moving platform is fixedly connected to the optical shaft. The optical shaft is also rotatably connected to the third link and the sixth link respectively through two bearings. The first, second, fifth, and sixth revolute joints are parallel and all parallel to the stationary platform; the third and fourth revolute joints are parallel and all parallel to the stationary platform; the rotation axis of the seventh revolute joint is perpendicular to the stationary platform; the eighth and ninth revolute joints are parallel to each other and parallel to the stationary platform; the rotation axes of the first, third, and fifth revolute joints are in the same plane, and the first and third revolute joints are arranged perpendicularly. Each branch kinematic chain is equipped with a kinematic chain drive mechanism between itself and the stationary platform to control the movement of the rotating pairs connected to the stationary platform in the branch kinematic chain.

[0009] Furthermore, the first universal joint, the second universal joint, and the third universal joint all have a first-direction revolute joint and a second-direction revolute joint with the rotation direction perpendicular to each other. The first direction revolute joint of the first universal joint and the first direction revolute joint of the third universal joint are respectively connected to the two ends of the third link. The third link is located on the line connecting the rotation axes of the first direction revolute joints of the first universal joint and the third universal joint. The second direction revolute joint of the first universal joint and the third universal joint is parallel to the first revolute joint. The first direction revolute joint of the second universal joint is connected to and parallel to the sixth link, and the second direction revolute joint of the second universal joint is parallel to the third revolute joint. The spherical joint has three revolute joints that are perpendicular to each other: a first spherical revolute joint, a second spherical revolute joint, and a third spherical revolute joint. The first spherical revolute joint is connected to the side of the moving platform, the second spherical revolute joint is parallel to the seventh revolute joint, and the third spherical revolute joint is parallel to the side of the moving platform where the spherical joint is located. The plane containing the rotation axes of the first and third spherical revolute joints is parallel to the moving platform. The first direction revolute joints of the first universal joint, the second universal joint, and the third universal joint are located in the same plane.

[0010] In this invention, parallelism or perpendicularity between rotating pairs refers to the parallelism or perpendicularity of the rotation axes of the rotating pairs.

[0011] The kinematic chain drive mechanism includes a kinematic chain drive motor, a motor synchronous pulley, a synchronous belt, and a connecting rod synchronous pulley. The kinematic chain drive motor is fixed on a stationary platform, and the connecting rod synchronous pulley is fixed on a rotating pair connected to the stationary platform on the corresponding kinematic chain, driving the rotating pair to rotate.

[0012] The sixth link consists of two short rods connected vertically, one of which is connected to the second universal joint, and the other is connected to the bearing on the optical axis.

[0013] The first, third, fifth, and seventh revolute joints have the same structure, including a hinge seat base, a hinge seat top seat, and a pin. The hinge seat base is rotatably connected to the hinge seat top seat via the pin.

[0014] In the first branch kinematic chain, the second branch kinematic chain, and the third branch kinematic chain, the hinge seat base is connected to the static platform via a profile-hinge connector.

[0015] The profile-hinge connector includes two vertical connecting surfaces, which are respectively connected to the static platform and the hinge base.

[0016] The static platform is a cross-shaped static platform, which is made of cross-shaped profiles connected together, and a branch kinematic chain is connected to each end of the cross-shaped static platform.

[0017] The moving platform is a rectangular moving platform formed by profiles. The outer side of one profile in the rectangular moving platform is connected to the spherical pair of the fourth branch kinematic chain. An optical axis bracket and a bearing seat are fixedly installed on the inner side of the other profile opposite to the first profile. The optical axis is fixed on the optical axis bracket. A first bearing, a second bearing, and a third bearing are installed on the optical axis from top to bottom. The third bearing is installed on the bearing seat. The first bearing is fixed in the middle of the third link, and the second bearing is fixed on the sixth link.

[0018] The wheel mechanism includes a fixed frame, a wheel motor mounted on the lower end of the fixed frame, and a traveling wheel. The wheel motor is a dual-axis motor, with a traveling wheel mounted on each of the two output shafts.

[0019] The detection device is a binocular depth camera.

[0020] The beneficial effects of this invention are: This invention utilizes a variable cell parallel mechanism in conjunction with a wheel-foot structure to achieve multi-posture adjustment of the variable cell vehicle, thereby improving the flexibility of vehicle movement; it also has multiple movement modes, making it widely applicable, with strong load capacity, and is mainly used in situations where the working road surface is mostly rugged and has obstacles, exhibiting good environmental adaptability; it also has high practical value in fields such as unmanned combat, disaster relief and rescue, material transportation, and resource exploration. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the cross-shaped static platform structure of the 3R1T parallel mechanism in this invention; Figure 3 This is a schematic diagram of the overall structure of the 3R1T parallel mechanism in this invention; Figure 4 This is a schematic diagram of the square moving platform structure of the 3R1T parallel mechanism in this invention; Figure 5 This is a schematic diagram of the wheel-foot mechanism in this invention; Figure 6 This is a schematic diagram illustrating the establishment of the spatial coordinate system for the 3R1T parallel mechanism in this invention; Figure 7 This is a simplified schematic diagram of the 3RRUR-RRRS parallel mechanism model of the present invention; Figure 8 This is a schematic diagram of the crawling posture of the variable cell vehicle described in this invention; Figure 9 This is a schematic diagram of the lifting posture of the variable cell vehicle described in this invention; Figure 10 This is a three-dimensional schematic diagram of the obstacle-crossing posture of the variable-cell vehicle described in this invention; Figure 11 This is a side view of the obstacle-crossing posture of the variable-cell vehicle described in this invention; Figure 12 This is a bottom-view schematic diagram of the rotating posture of the variable cell vehicle described in this invention; Figure 13 This is a three-dimensional schematic diagram of the rotational posture of the variable cell vehicle described in this invention.

[0023] The diagram is labeled as follows: 1. 3R1T parallel mechanism; 100. Cross-shaped stationary platform; 101. Angle bracket; 110. Rectangular moving platform; 111. Moving platform profile; 112. Optical axis bracket; 113. Optical axis; 114. Bearing seat; 115. First bearing; 116. Second bearing; 117. Third bearing; 120. Profile-hinge connection seat; 130. Kinematic chain drive motor; 131. Motor synchronous pulley; 132. Synchronous belt; 133. Connecting rod synchronous pulley; 140. Hinge seat base; 141. Hinge seat top seat; 142. Pin. L1, first branch kinematic chain; R11, first revolute joint; R12, second revolute joint; U13, first universal joint; 1-1, first link; 1-2, second link; 1-3, third link. L2, second branch kinematic chain; R21, third revolute joint; R22, fourth revolute joint; U23, second universal joint; 1-4, fourth link; 1-5, fifth link; 1-6, sixth link. L3, third branch kinematic chain; R31, fifth revolute joint; R32, sixth revolute joint; U33, third universal joint; 1-7, seventh link; 1-8, eighth link; L4, fourth branch kinematic chain; R41, seventh revolute joint; R42, eighth revolute joint; R43, ninth revolute joint; S44, spherical joint; 1-9, ninth link; 1-10, tenth link; 1-11, eleventh link. R51, tenth revolute joint; R52, eleventh revolute joint; 2. Wheel and foot mechanism, 201. Fixed frame, 202. Motor bearing, 203. Wheel and foot motor, 204. Walking wheel; 3. Body frame, 301 square tube, 302 parallel structure fixing plate; 4. Detection device; 5. Obstacle; 6. Ground. Detailed Implementation

[0024] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments, but this should not be construed as limiting the invention in any way.

[0025] like Figure 1 As shown, the present invention discloses a multi-attitude variable-form vehicle based on a four-degree-of-freedom parallel mechanism, comprising a 3R1T parallel mechanism 1, a wheel-foot mechanism 2, a body frame 3, and a detection device 4. The body frame 3 is composed of four square tubes 301 vertically fixed in pairs, with parallel mechanism fixing plates 302 fixed to the lower surfaces of the four corners of the body frame 3. Each parallel mechanism fixing plate 302 has a 3R1T parallel mechanism 1 connected to its lower surface, and the lower end of the 3R1T parallel mechanism 1 is connected to the wheel-foot mechanism 2. The wheel-foot mechanism 2 is used to enable the vehicle to move. The detection device 4 is a binocular depth camera, which is installed in four directions on each square tube 301 of the body frame 3.

[0026] like Figure 2 , 3 As shown, the 3R1T parallel mechanism 1 includes a cross-shaped static platform 100, four branch kinematic chains, and a rectangular moving platform 110. The four branch kinematic chains are the first branch kinematic chain L1, the second branch kinematic chain L2, the third branch kinematic chain L3, and the fourth branch kinematic chain L4.

[0027] like Figure 2 As shown, the cross-shaped stationary platform 100 includes cross-shaped profiles and angle brackets 101 for vertical connection between the profiles. The cross-shaped stationary platform 100 is fixed to the lower surface of the parallel mechanism fixing plate 302.

[0028] like Figure 3 As shown, among the four branch kinematic chains, the first branch kinematic chain L1, the second branch kinematic chain L2, and the third branch kinematic chain L3 have the same structure, each including two revolute joints, three connecting rods, and one universal joint. The end of the first branch kinematic chain L1 and the end of the third branch kinematic chain L3 share a connecting rod. The fourth branch kinematic chain L4 includes three revolute joints, one spherical joint, and three connecting rods. The first branch kinematic chain L1 and the third branch kinematic chain L3 are arranged opposite each other in the first direction of the 3R1T parallel mechanism. The upper ends of the first branch kinematic chain L1 and the third branch kinematic chain L3 are connected to opposite ends of the cross stationary platform 100, and the lower ends are connected to opposite sides of the rectangular moving platform 110. The second branch kinematic chain L2 and the fourth branch kinematic chain L4 are arranged opposite each other in the second direction of the 3R1T parallel mechanism. The upper ends of the second branch kinematic chain L2 and the fourth branch kinematic chain L4 are connected to the other two ends of the cross stationary platform 100, and the lower ends are connected to the other two opposite sides of the rectangular moving platform 110. The first and second directions of the 3R1T parallel mechanism correspond to the straight lines of the cross-shaped profiles of the cross static platform 100.

[0029] The following is in conjunction with the appendix Figure 3 The structure of the four branch kinetic chains will be explained in more detail.

[0030] The first branch kinematic chain L1 includes a first revolute joint R11, a second revolute joint R12, a first universal joint U13, a first connecting rod 1-1, a second connecting rod 1-2, and a third connecting rod 1-3. The first revolute joint R11 consists of a hinge seat base 140, a hinge seat top seat 141, and a pin 142. The hinge seat base 140 and the hinge seat top seat 141 are rotatably connected by the pin 142, and the pin 142 is fixed on the hinge seat top seat 141. The hinge seat base 140 is fixedly connected to one end of the profile-hinge connection seat 120, and the other end of the profile-hinge connection seat 120 is fixedly connected to one end of the cross stationary platform 100 in the first direction. The profile-hinge connection seat 120 is a right-angle connection seat with two right-angle surfaces, which are respectively connected to the profile end face of the cross stationary platform 100 and the hinge seat base 140. The hinge seat top seat 141 is fixedly connected to the upper end of the first connecting rod 1-1. The lower end of the first connecting rod 1-1 is connected to one end of the second revolute joint R12. The other end of the second revolute joint R12 is connected to the upper end of the second connecting rod 1-2. The lower end of the second connecting rod 1-2 is connected to one end of the first universal joint U13. The other end of the first universal joint U13 is connected to one end of the third connecting rod 1-3. The other end of the third connecting rod 1-3 is connected to the third universal joint U33 of the third branch kinematic chain L3. Therefore, the first branch kinematic chain L1 and the third branch kinematic chain L3 share the third connecting rod 1-3. The middle part of the third connecting rod 1-3 is rotatably connected to the rectangular moving platform 110, and the axis of rotation is perpendicular to the rectangular moving platform 110.

[0031] The second branch kinematic chain L2 includes the third revolute joint R21, the fourth revolute joint R22, the second universal joint U23, and the fourth link 1-4, the fifth link 1-5, and the sixth link 1-6. The structure of the third rotary joint R21 is the same as that of the first rotary joint R11. One end of the third rotary joint R21 is connected to the profile end face in the second direction of the cross stationary platform 100 through the profile-hinge connecting seat 120. The other end of the third rotary joint R21 is connected to the upper end of the fourth link 1-4. The lower end of the fourth link 1-4 is connected to one end of the fourth rotary joint R22. The other end of the fourth rotary joint R22 is connected to the upper end of the fifth link 1-5. The lower end of the fifth link 1-5 is connected to one end of the second universal joint U23. The other end of the second universal joint U23 is connected to one end of the sixth link 1-6. The other end of the sixth link 1-6 is rotatably connected to the rectangular moving platform 110, and the rotation axis coincides with the rotation axis between the third link 1-3 and the rectangular moving platform 110.

[0032] The third branch kinematic chain L3 includes a fifth rotary joint R31, a sixth rotary joint R32, a third universal joint U33, a seventh link 1-7, an eighth link 1-8, and a third link 1-3 shared with the first branch kinematic chain L1. The structure of the fifth rotary joint R31 is the same as that of the first rotary joint R11. One end of the fifth rotary joint R31 is connected to another profile end face in the first direction of the cross stationary platform 100 through a profile-hinge connector 120. The other end of the fifth rotary joint R31 is connected to the upper end of the seventh link 1-7. The lower end of the seventh link 1-7 is connected to one end of the sixth rotary joint R32. The other end of the sixth rotary joint R32 is connected to the upper end of the eighth link 1-8. The lower end of the eighth link 1-8 is connected to one end of the third universal joint U33. The other end of the third universal joint U33 is connected to one end of the third link 1-3.

[0033] The fourth branch kinematic chain L4 includes a seventh revolute joint R41, an eighth revolute joint R42, a ninth revolute joint R43, a spherical joint S44, and a ninth link 1-9, a tenth link 1-10, and an eleventh link 1-11. The structure of the seventh revolute joint R41 is the same as that of the first revolute joint R11. One end of the seventh revolute joint R41 is directly connected to the other profile end face of the cross stationary platform 100 in the second direction, and the other end is connected to the upper end of the ninth link 1-9. The lower end of the ninth link 1-9 is connected to one end of the eighth revolute joint R42. The other end of the eighth revolute joint R42 is connected to the upper end of the tenth link 1-10. The lower end of the tenth link 1-10 is connected to one end of the ninth revolute joint R43. The other end of the ninth revolute joint R43 is connected to the upper end of the eleventh link 1-11. The lower end of the eleventh link 1-11 is connected to one end of the spherical joint S44, and the other end of the spherical joint S44 is connected to one side of the rectangular moving platform 110.

[0034] Each branch kinematic chain also has a kinematic chain drive mechanism to drive the corresponding kinematic chain action. The structure and driving method of the kinematic chain drive mechanisms for the four branch kinematic chains are similar. For example... Figure 3As shown, taking the first branch kinematic chain L1 as an example, its kinematic chain drive mechanism includes a kinematic chain drive motor 130, a motor synchronous pulley 131, a synchronous belt 132, and a connecting rod synchronous pulley 133. The kinematic chain drive motor 130 is fixed on the profile of the cross stationary platform. The motor synchronous pulley 131 is mounted on the output shaft of the kinematic chain drive motor 130. The connecting rod synchronous pulley 133 is mounted on the pin 142 of the first rotating pair R11. The synchronous belt 132 connects the motor synchronous pulley 131 and the connecting rod synchronous pulley 133. Furthermore, the pin 142, the connecting rod synchronous pulley 133, and the hinge seat top seat 141 are welded together to form a rigid body. The kinematic chain drive motor 130 provides rotational power, which is transmitted to the corresponding branch kinematic chain through the synchronous pulley and the synchronous belt, driving the branch kinematic chain to move. The first, second, and third branch kinematic chains achieve telescopic movements under the drive mechanism, which are used to make the rectangular moving platform 110 swing in different directions; the fourth branch kinematic chain rotates around the seventh rotary joint R41 under the drive mechanism, which is used to drive the rectangular moving platform 110 to rotate.

[0035] The structure of the rectangular moving platform 110 is as follows: Figure 4 As shown, the rectangular moving platform 110 includes a rectangular frame composed of moving platform profiles 111 joined end to end. The lower plane of the rectangular frame is connected to the fixed frame of the wheel foot mechanism 2. The outer side of the rectangular frame corresponding to the fourth branch kinematic chain L4 is connected to the spherical joint S44. The optical axis support 112 and bearing seat 114 are fixedly installed on the inner side of the rectangular frame corresponding to the second branch kinematic chain L2. The optical axis 113, perpendicular to the rectangular frame, is fixed on the optical axis support 112. The first bearing 115, the second bearing 116, and the third bearing 117 are installed on the optical axis 113 from top to bottom. The third bearing 117 is fixed on the bearing seat 114. The second bearing 116 is fixed in the sixth link 1-6 at the end of the second branch kinematic chain L2, forming the tenth rotating joint R51. The first bearing 115 is fixed in the middle of the third link 1-3, forming the eleventh rotating joint R52.

[0036] Preferably, by setting the mounting position of the second bearing 116 on the optical axis 113, the third bearing 117 abuts against the second bearing 116, so that the lower surface of the sixth link 1-6 is higher than the surface of the moving platform profile 111 of the rectangular moving platform 110, thus avoiding friction between the moving platform profile 111 of the rectangular moving platform 110 and the sixth link 1-6.

[0037] The structure of the wheel leg mechanism 2 is as follows: Figure 5As shown, the system includes a fixed frame 201, a motor bearing 202, a wheel motor 203, and two wheels 204. The upper part of the fixed frame 201 is a support plate for fixed connection to the rectangular frame of the rectangular moving platform 110. The lower part of the fixed frame 201 consists of two parallel, spaced-apart support arms perpendicular to the support plate. The upper ends of the support arms are fixed to the lower surface of the support plate, and the lower ends of the support arms have two mounting slots for mounting the motor bearing 202. The wheel motor 203 is mounted between the two support arms, and its two output shafts pass through the two motor bearings 202 and connect to the two wheels 204.

[0038] The following is combined Figure 6 , 7 The motion of the four branch kinematic chains of the present invention will be described.

[0039] like Figure 6 As shown, for the 3R1T parallel mechanism 1 of the present invention, a spatial coordinate system is established with the center of the cross-shaped stationary platform 100 as the origin Q of the coordinate system, the length direction of the cross-shaped profile of the cross-shaped stationary platform as the X-axis and Y-axis, and the vertical downward direction as the Z-axis. Q-XYZ Therefore, the first direction of the 3R1T parallel mechanism is... X The direction of the axis, the second direction is Y The direction of the axis. Establish a spatial coordinate system near the rectangular moving platform 110. O-uvw , QO It is a straight line in the vertical direction. Therefore, u shaft and x The axes are parallel. v shaft and Y The axes are parallel. w shaft and Z The axes coincide. On the rectangular moving platform and the plane... XY When parallel, the third link 1-3 and u The axes are parallel, and the optical axis 113 is in w On the axis, straight line QO The Z-axis and W-axis are collinear. For ease of explanation, the 3R1T parallel mechanism 1 is simplified as follows: Figure 7 The model shown is a 3RRUR-RRRS parallel mechanism.

[0040] Figure 6 and Figure 7 The shown mechanism represents the initial state of the variable-cell vehicle. At this point, the variable-cell vehicle is positioned on a horizontal plane, and the rectangular moving platform 110 is perpendicular to the plane. XY Parallel, meaning parallel to the stationary cross platform 100 and also parallel to the horizontal plane. The following descriptions of the rotation axis directions of each revolute joint and the connecting rod directions in the mechanism are all based on this initial state.

[0041] like Figure 7 As shown, the rotation axes of the first revolute joint R11 and the second revolute joint R12 of the first branch kinematic chain L1, and the fifth revolute joint R31 and the sixth revolute joint R32 of the third branch kinematic chain L3, are all perpendicular to... Y The axes are parallel, and the first universal joint U13 has two revolute joints with perpendicular rotational directions, namely R... 11 and R 12 The third universal joint U33 has two revolute joints with perpendicular rotational directions: a first-direction revolute joint and a second-direction revolute joint, which are R... 31 and R 32 , where R 11 and R 31 Connected to both ends of the third link 1-3 respectively, and R 11 and R 31 The axes of rotation are collinear and parallel to the third link 1-3, passing through R. 11 and R 31 Rotation enables the rectangular moving platform 110 to rotate at R. 11 or R 31 The axis of rotation is the axis of rotation; R 12 and R 32 The rotation axes of all three links are parallel to the plane of the rectangular moving platform 110. The third connecting rod 1-3 is located in the revolute joint R. 11 and R 31 On the axis of rotation, the eleventh rotating joint R52 formed by the third link 1-3 and the first bearing 115 allows the rectangular moving platform 110 to rotate relative to the third link 1-3 about the optical axis 113.

[0042] like Figure 7 As shown, the rotation axes of the third revolute joint R21 and the fourth revolute joint R22 of the second branch kinematic chain L2 are parallel to... X The axes are parallel, and the second universal joint U23 has two revolute joints with perpendicular rotational directions: a first-direction revolute joint and a second-direction revolute joint, which are R... 21 and R 22 Second direction rotary joint R 22 Parallel to the third revolute joint R21 and the fourth revolute joint R22, while the second direction revolute joint R 22 The axis of rotation is also related to u The axes are parallel, and the first direction revolute joint R 21 Connected to the sixth link, and the first direction revolute joint R 21 The axis of rotation is parallel to the sixth link. Figure 7 In the initial state shown, the first direction revolute joint R 21The axis of rotation is located in the plane uv. The end of the sixth link 1-6 forms the tenth rotating pair R51 with the second bearing 116, so that the rectangular moving platform 110 can rotate relative to the sixth link 1-6 with the optical axis 113 as the center.

[0043] like Figure 7 As shown, the rotation axis of the seventh revolute joint R41 of the fourth branch kinematic chain L4 is parallel to the axis of rotation of the fourth branch kinematic chain L4. Z The axes of rotation of the eighth revolute joint R42 and the ninth revolute joint R43 are both perpendicular to the axis. Q-XYZ The XY planes in the coordinate system are parallel; the spherical joint S44 has three revolute joints with mutually perpendicular rotation axes, namely the first spherical revolute joint R... 41 , second spherical revolute joint R 42 and the third revolute joint R of the spherical surface 43 Among them, the first spherical revolute joint R 41 Connected to the outer side of the rectangular moving platform 110 frame, the spherical second revolute joint R 42 The axis of rotation and w The axes are parallel, and the third spherical revolute joint R 43 The axis of rotation is parallel to the edge of the moving platform where the spherical pair S44 is located.

[0044] In the 3R1T parallel mechanism, the rotation axes of the first rotary joint R11, the third rotary joint R21, and the fifth rotary joint R31 are all in the same plane, i.e. Q-XYZ In the coordinate system XY Plane; three revolute joints R in three directions among the three universal joints 11 R 21 and R 31 The axes of rotation are in the same plane, i.e., the coordinate system. O-uvw In UV Plane. Since both the third link 1-3 and the sixth link 1-6 are rotatably connected to the optical axis, the two links must be positioned vertically to ensure the rotational joint R in three directions. 11 R 21 and R 31 The axis of rotation is located UV In the plane, the sixth link 1-6 needs to be set in a "Z" shape, that is, it includes two segments connected vertically. One segment is coplanar with the third link and connected to the second universal joint U23, and the other segment is connected to the second bearing 116.

[0045] The 3R1T parallel mechanism is a partially decoupled mechanism; the rectangular moving platform can achieve four degrees of freedom (3R1T), that is, it can achieve rotational movement. u axis, v axis, w Shaft rotation and along w Axis movement.

[0046] When the rectangular moving platform starts to rotate from the initial state u When the shaft rotates, the motion chain drive mechanisms of the first, third, and fourth branch motion chains remain stationary, while the motion chain drive mechanism of the second branch motion chain controls the second branch motion chain to perform extension and retraction movements.

[0047] When the rectangular platform starts to rotate from the initial state v When the shaft rotates, the motion chain drive mechanisms of the second and fourth branch motion chains remain stationary, while the motion chain drive mechanisms of the first and third branch motion chains control the first and third branch motion chains to perform extension and retraction movements.

[0048] When the rectangular platform starts to rotate from the initial state w When the shaft rotates, the motion chain drive mechanisms of the first, second, and third branch motion chains remain stationary, while the motion chain drive mechanism of the fourth branch motion chain controls the fourth branch motion chain to perform rotational motion.

[0049] When the rectangular platform starts from the initial state along w When the axis moves, the motion chain drive mechanism of the fourth branch motion chain remains stationary, while the motion chain drive mechanisms of the first, second, and third branch motion chains control the corresponding motion chains to perform extension and retraction actions.

[0050] like Figure 8 As shown, when the four parallel mechanisms of the variable cell vehicle all move along w When the axle retracts, the entire modular vehicle can maintain a crawling posture to cope with situations where height space is limited. Figure 8 The vehicle is traveling on ground 601, with obstacle 600 above it.

[0051] like Figure 9 As shown, when the four parallel mechanisms of the variable cell vehicle all move along w When the axle extends, the entire modular vehicle can be raised to cope with situations where there are obstacles at low heights and ample vertical space.

[0052] like Figure 10 , 11 As shown, when one of the parallel mechanisms of the variable cell vehicle is in operation w With the axle retracted and the other parallel mechanisms not adjusted in height, when encountering only one obstacle, the forward propulsion is still provided by the wheels in the other parallel mechanisms, thus enabling the variable-sized vehicle to overcome obstacles and cope with situations where there are obstacles on the ground.

[0053] like Figure 12 , 13 As shown, the motion chain drive mechanism at the upper end of the fourth branch motion chain L4 in the parallel mechanism can drive the fourth branch motion chain L4 and the rectangular moving platform 110 to rotate around w The shaft rotates, and all parallel mechanisms of the variable cell vehicle rotate around it. wThe rotation of the axis allows for adjustment of the wheel feet to a suitable angle, thus enabling the variable-sized vehicle to adjust its rotational attitude. Therefore, all four sides can serve as the vehicle's direction of travel, addressing situations where space is limited but angle adjustments are necessary. Furthermore, the extension and retraction of the first, second, and third branch kinematic chains can also be used to adjust the wheel feet's rotational position. u axis, v The rotation of the shaft is used to cope with complex, uneven road conditions.

[0054] Under normal circumstances, the wheel motor 203 in the wheel mechanism 2 provides power to realize the wheel movement mode; when switching to the crawling posture or lifting posture of the variable cell vehicle, the variable height movement mode is realized; when switching to the rotating posture of the variable cell vehicle, the stationary rotation mode is realized; in conjunction with the four binocular depth cameras on the variable cell vehicle and the aforementioned multiple postures, the path tracking movement mode is realized.

[0055] In other embodiments, the top ends of the first branch kinematic chain, the second branch kinematic chain, and the third branch kinematic chain may be directly connected to the profile of the cross stationary platform instead of being connected to the cross stationary platform via a profile-hinge connector.

[0056] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Those skilled in the art should understand that modifications or equivalent substitutions can be made to the specific implementation of the present invention with reference to the above embodiments. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention are within the protection scope of the pending claims.

Claims

1. A multi-attitude variable cell vehicle based on a four-degree-of-freedom parallel mechanism, characterized in that: It includes a 3R1T parallel mechanism (1), a wheel-foot mechanism (2), a body frame (3), and a detection device (4). There are four 3R1T parallel mechanisms (1), which are distributed at the four corners of the body frame (3). The lower end of the 3R1T parallel mechanism (1) is connected to the wheel-foot mechanism (2). The wheel-foot mechanism (2) is used to realize the movement of the variable cell vehicle. The detection device (4) is arranged in the four directions of the body frame (3). The 3R1T parallel mechanism (1) includes a static platform, a moving platform and four branch kinematic chains between the two platforms. The first branch kinematic chain (L1) and the third branch kinematic chain (L3) are arranged opposite to each other in the first direction of the 3R1T parallel mechanism, and the second branch kinematic chain (L2) and the fourth branch kinematic chain (L4) are arranged opposite to each other in the second direction of the 3R1T parallel mechanism. The first direction is perpendicular to the second direction. The first branch kinematic chain (L1) includes a first link (1-1) and a second link (1-2). The first link (1-1) and the second link (1-2) are connected by a second revolute joint (R12). The first link (1-1) is connected to the stationary platform by a first revolute joint (R11). The second link (1-2) is connected to one end of the third link (1-3) by a first universal joint (U13). The second branch kinematic chain (L2) includes a fourth link (1-4), a fifth link (1-5), and a sixth link (1-6). The fourth link (1-4) and the fifth link (1-5) are connected by a fourth revolute joint (R22). The fourth link (1-4) is connected to the stationary platform by a third revolute joint (R21). The fifth link (1-5) is connected to one end of the sixth link (1-6) by a second universal joint (U23). The third branch kinematic chain (L3) includes a seventh link (1-7) and an eighth link (1-8). The seventh link (1-7) and the eighth link (1-8) are connected by a sixth revolute joint (R32). The seventh link (1-7) is connected to the stationary platform by a fifth revolute joint (R31). The eighth link (1-8) is connected to the other end of the third link (1-3) by a third universal joint (U33). The fourth branch kinematic chain (L4) includes the ninth link (1-9), the tenth link (1-10), and the eleventh link (1-11). The three links are connected sequentially through the eighth revolute joint (R42) and the ninth revolute joint (R43). The ninth link (1-9) is connected to the stationary platform through the seventh revolute joint (R41), and the eleventh link (1-11) is connected to the moving platform through the spherical joint (S44). The moving platform is fixed on the fixed frame (201) of the wheel foot mechanism (2). The moving platform is fixedly connected to the optical axis (113). The optical axis is perpendicular to the upper surface of the moving platform. The optical axis (113) is also rotatably connected to the third link (1-3) and the sixth link (1-6) respectively through two bearings. The first revolute joint (R11), the second revolute joint (R12), the fifth revolute joint (R31), and the sixth revolute joint (R32) are parallel and all parallel to the stationary platform; the third revolute joint (R21) and the fourth revolute joint (R22) are parallel and all parallel to the stationary platform; the axis of rotation of the seventh revolute joint (R41) is perpendicular to the stationary platform; the eighth revolute joint (R42) and the ninth revolute joint (R43) are parallel to each other and parallel to the stationary platform; the axes of rotation of the first revolute joint (R11), the third revolute joint (R21), and the fifth revolute joint (R31) are in the same plane, and the first revolute joint (R11) and the third revolute joint (R21) are arranged perpendicularly; Each branch kinematic chain and the stationary platform are equipped with a kinematic chain drive mechanism to control the movement of the rotating pairs connected to the stationary platform in the branch kinematic chain. The configuration and spatial position of the first branch kinematic chain (L1), the second branch kinematic chain (L2), the third branch kinematic chain (L3), and the fourth branch kinematic chain (L4) are set as follows: when the moving platform rotates about a first direction, it is driven by the extension and retraction of the second branch kinematic chain (L2); when the moving platform rotates about a second direction, it is driven by the extension and retraction of the first branch kinematic chain (L1) and the third branch kinematic chain (L3); when the moving platform rotates about a direction perpendicular to the stationary platform, it is driven by the fourth branch kinematic chain (L4); when the moving platform translates along a direction perpendicular to the stationary platform, it is driven by the extension and retraction of the first branch kinematic chain (L1), the second branch kinematic chain (L2), and the third branch kinematic chain (L3).

2. The multi-posture variable-cell vehicle according to claim 1, characterized in that: The first universal joint (U13), the second universal joint (U23), and the third universal joint (U33) all have a first-direction revolute joint and a second-direction revolute joint with the rotation direction perpendicular to each other; The first direction revolute joint of the first universal joint (U13) and the first direction revolute joint of the third universal joint (U33) are respectively connected to the two ends of the third link. The third link (1-3) is located on the line connecting the rotation axes of the first direction revolute joints of the first universal joint (U13) and the third universal joint (U33). The second direction revolute joints of the first universal joint (U13) and the third universal joint (U33) are parallel to the first revolute joint (R11). The first direction revolute joint of the second universal joint (U23) is connected to the sixth link (1-6) and is parallel to the sixth link (1-6). The second direction revolute joint of the second universal joint (U23) is parallel to the third revolute joint (R21). The spherical joint (S44) has three mutually perpendicular revolute joints, namely the first spherical revolute joint (R... 41 ), spherical second revolute joint (R) 42 ) and the third revolute joint of the spherical surface (R 43 ), spherical first revolute joint (R 41 The spherical second revolute joint (R) is connected to the side of the moving platform. 42 ) is parallel to the seventh revolute joint (R41), and the third revolute joint on the spherical surface (R 43 The first spherical revolute joint (R) is parallel to the side of the moving platform where the spherical joint (S44) is located; 41 ) and the third revolute joint of the spherical surface (R 43 The plane containing the axis of rotation of the moving platform is parallel to the moving platform. The first direction rotational joints of the first universal joint (U13), the second universal joint (U23), and the third universal joint (U33) are located in the same plane.

3. The multi-posture variable cell vehicle according to claim 1, characterized in that: The kinematic chain drive mechanism includes a kinematic chain drive motor (130), a motor synchronous pulley (131), a synchronous belt (132), and a connecting rod synchronous pulley (133). The kinematic chain drive motor (130) is fixed on a stationary platform, and the connecting rod synchronous pulley (133) is fixed on a rotating pair connected to the stationary platform on the corresponding kinematic chain, driving the rotating pair to rotate.

4. The multi-posture variable cell vehicle according to claim 1, characterized in that: The sixth link (1-6) consists of two short rods connected vertically. One short rod is connected to the second universal joint (U23), and the other short rod is connected to the bearing on the optical axis (113).

5. The multi-posture variable-cell vehicle according to claim 1, characterized in that: The first rotating joint (R11), the third rotating joint (R21), the fifth rotating joint (R31) and the seventh rotating joint (R41) have the same structure, including a hinge seat base (140), a hinge seat top seat (141) and a pin (142). The hinge seat base (140) is rotatably connected to the hinge seat top seat (141) through the pin (142).

6. The multi-posture variable cell vehicle according to claim 5, characterized in that: In the first branch kinematic chain (L1), the second branch kinematic chain (L2), and the third branch kinematic chain (L3), the hinge seat base (140) is connected to the static platform via a profile-hinge connector (120).

7. The multi-posture variable-cell vehicle according to claim 1, characterized in that: The static platform is a cross-shaped static platform (100), which is made of cross-shaped profiles connected together, and a branch kinematic chain is connected to each end of the cross-shaped static platform (100).

8. The multi-posture variable cell vehicle according to claim 1, characterized in that: The moving platform is a rectangular moving platform (110) formed by profiles. The outer side of one profile in the rectangular moving platform (110) is connected to the spherical pair (S44) of the fourth branch kinematic chain (L4). The inner side of the other profile opposite to the profile is fixedly provided with an optical axis bracket (112) and a bearing seat (114). The optical axis (113) is fixed on the optical axis bracket (112). The first bearing (115), the second bearing (116) and the third bearing (117) are installed on the optical axis (113) from top to bottom. The third bearing (117) is installed on the bearing seat (114). The first bearing (115) is fixed in the middle of the third link (1-3), and the second bearing (116) is fixed on the sixth link (1-6).

9. The multi-posture variable cell vehicle according to claim 1, characterized in that: The wheel mechanism (2) includes a fixed frame (201), a wheel motor (203) installed at the lower end of the fixed frame (201), and a walking wheel (204). The wheel motor (203) is a dual-axis motor, with a walking wheel (204) on each of the two output shafts.

10. The multi-posture variable cell vehicle according to claim 1, characterized in that: The detection device (4) is a binocular depth camera.

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