A low-power consumption unidirectional transmission hexapod robot and a foot end trajectory correction method thereof

Abstract

The application discloses a low-power-consumption unidirectional transmission hexapod robot and a foot end trajectory correction method thereof, and belongs to the field of robot design. In order to solve the problems of high energy consumption, heavy structure, complex control, high cost and low reliability of the existing robots, the application comprises sequentially connected hip joints, thighs, knee joints, shanks and feet, and a unidirectional transmission mechanism for controlling the gait of the shank. The thigh is a deformable four-link mechanism, and the unidirectional transmission mechanism is connected between the thigh and the hip joint. When the hip joint is driven to rotate forward, the thigh is driven to deform through the transmission cooperation of the unidirectional transmission mechanism, so that the thigh drives the shank to complete the swing action of lifting and falling. When the hip joint is driven to rotate reversely, the unidirectional transmission mechanism does not transmit motion, and the thigh does not deform any more, so that the foot always keeps in contact with the ground and supports the ground. The application is mainly used for executing tasks such as complex environment exploration, disaster rescue and planet exploration.

Description

Technical Field

[0001] This invention relates to the field of robot design, and more particularly to a low-power, unidirectional transmission hexapod robot and a method for correcting the trajectory of its legs. Background Technology

[0002] Hexapods, mimicking the six-legged locomotion of insects, possess excellent terrain adaptability, good static stability, and flexible gait, demonstrating enormous application potential in fields such as complex environment exploration, disaster relief, and planetary exploration. Compared to bipedal or quadrupedal robots, hexapods can walk stably on uneven ground through the coordinated movement of their multiple legs.

[0003] Currently, mainstream hexapod robots typically employ a series-jointed leg structure. Each leg is generally designed with a three-degree-of-freedom motion mechanism, corresponding to hip joint pitch / yaw and knee joint pitch movements, enabling precise positioning and flexible movement of the foot in three-dimensional space. To achieve independent control of these three degrees of freedom, each leg usually requires three independent drive motors. Therefore, a complete hexapod robot requires at least 18 drive motors. Since drive motors are the robot's main energy-consuming units, the simultaneous or alternating operation of 18 motors results in enormous power consumption and a significantly shortened runtime, making it difficult to meet the demands of long-term operation. It also increases control complexity. Furthermore, the large number of motors and their associated structures significantly increases the robot's weight and size. This not only increases manufacturing costs but also further increases power consumption. In summary, existing hexapod robots suffer from a series of problems, including high energy consumption, bulky structure, complex control, high cost, and relatively low reliability. Summary of the Invention

[0004] In view of this, the present invention provides a low-power unidirectional transmission hexapod robot and its foot trajectory correction method. It utilizes the unidirectional power transmission characteristics of the unidirectional transmission mechanism to convert the rotational motion of the hip joint into the motion of the thigh and lower leg, eliminating the need for a knee joint motor and meeting the requirements of low energy consumption.

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

[0006] In a first aspect, the present invention provides a low-power, unidirectional transmission hexapod robot, comprising a body and six leg structures. The six leg structures are symmetrically arranged on the left and right sides of the body. Each leg structure includes a hip joint, thigh, knee joint, lower leg, and foot connected in sequence, as well as a unidirectional transmission mechanism for controlling the gait of the lower leg. The thigh is a deformable four-bar linkage, and the unidirectional transmission mechanism connects the thigh and the hip joint. When the hip joint is driven to rotate forward, the thigh is driven to deform through the transmission of the unidirectional transmission mechanism, so that the thigh drives the lower leg to complete the swing phase of lifting and lowering. When the hip joint is driven to rotate in the opposite direction, the unidirectional transmission mechanism does not transmit motion, and the thigh no longer deforms, so that the foot always maintains contact with the ground and supports itself by pushing off the ground.

[0007] Furthermore, the hip joint includes a first joint shaft and a joint housing, the joint housing being rotatably mounted to the robot's body via the first joint shaft; the one-way transmission mechanism includes a fixed bevel gear, a driving bevel gear, a gear shaft, a one-way bearing, and a first flexible transmission assembly; the fixed bevel gear is connected to the robot body and remains stationary; the gear shaft is rotatably mounted inside the joint housing, the driving bevel gear is fitted onto the gear shaft via the one-way bearing, and meshes with the fixed bevel gear; the first flexible transmission assembly connects the gear shaft to the thigh for power transmission.

[0008] Furthermore, the first flexible transmission assembly includes a driving pulley, a driven pulley, and a timing belt. The driving pulley is sleeved on the gear shaft and can rotate with the gear shaft; the driven pulley is sleeved on one of the pins on the thigh; and the timing belt wraps around the driving pulley and the driven pulley and is tensioned.

[0009] Furthermore, it also includes a rope drive mechanism for driving the lateral swing of the lower leg. The rope drive mechanism includes an active winding reel, a driven winding reel, a wire rope, and a torsion spring. The active winding reel is mounted on the first joint shaft; the driven winding reel is mounted on the second joint shaft of the knee joint; one end of the wire rope is wound around the active winding reel, and the other end is wound around the driven winding reel; the torsion spring is mounted on the second joint shaft for resetting the driven winding reel.

[0010] Furthermore, a sliding rod is provided at the foot, through which the foot and lower leg are slidably connected, and a buffer spring is fitted on the sliding rod.

[0011] Furthermore, it also includes a first drive mechanism and a second drive mechanism, with the leg structure on each side being a front leg, a middle leg, and a rear leg, respectively; there are two first drive mechanisms, which are symmetrically arranged inside the fuselage, and each first drive mechanism drives the front leg and the rear leg on the same side; there are two second drive mechanisms, which are symmetrically arranged inside the fuselage, and each second drive mechanism drives the middle leg on the same side.

[0012] Furthermore, the first drive mechanism includes a first drive motor, a worm gear assembly, and a second flexible transmission assembly. Both the worm gear assembly and the second flexible transmission assembly are provided in two sets, with one set corresponding to the front leg and the other set corresponding to the rear leg. Each worm gear assembly includes a meshing first worm wheel and a first worm. Each second flexible transmission assembly includes a first sprocket, a second sprocket, and a first chain. The first worm in both sets of worm gear assemblies is coaxially connected to the motor shaft of the first drive motor. The two first worm wheels are rotatably mounted on the machine body and coaxially connected to the corresponding first sprocket. The second sprocket is fitted onto the first joint shaft in the corresponding leg structure. The first chain wraps around the first and second sprockets and is tensioned.

[0013] Furthermore, the second drive mechanism includes a second drive motor and a third flexible transmission assembly. The third flexible transmission assembly includes a third sprocket, a fourth sprocket, and a second chain. The third sprocket is connected to the motor shaft of the second drive motor, the fourth sprocket is fitted onto the first joint shaft in the corresponding leg structure, and the second chain wraps around the third sprocket and the fourth sprocket and is tensioned.

[0014] Secondly, the present invention provides a method for correcting the foot trajectory of a low-power unidirectional transmission hexapod robot. For the low-power unidirectional transmission hexapod robot described in the first aspect, the foot trajectory is corrected by setting a geometric coupling coefficient for the winding wheel. The set geometric coupling coefficient for the winding wheel is as follows:

[0015]

[0016] in, This represents the maximum swing angle of the hip joint. This refers to the length of the robot's lower leg. , This is the distance between the first and third pins. This is the distance between the first pin and the second joint pin. This is the distance from the center of hip joint rotation to the third pivot pin. The initial angle for the input angle of the active crank; For direction coefficients, The maximum swing angle of the lower leg axis relative to the vertical direction of the knee joint;

[0017] This represents an analytic function of the output angle with respect to the input angle, for... have:

[0018]

[0019]

[0020] in, This is the distance between the second and third pins. This is the distance between the second pin and the second joint.

[0021] Furthermore, the directional coefficient Through hip joint angle and knee joint angle The linear relationship between them is determined, that is ,in The geometric coupling coefficient is... The radius of the active winding reel at the hip joint. The radius of the driven winding wheel at the knee joint.

[0022] The beneficial effects of this invention compared to the prior art are:

[0023] 1. This invention introduces a one-way transmission mechanism, utilizing its characteristic of unidirectional power transmission to achieve coordinated control between the hip and knee joint movements. Specifically, when the hip joint undergoes forward rotation, the one-way transmission mechanism effectively transmits power to the knee joint, thereby driving the lower leg to complete the swing phase movements of lifting and lowering. When the hip joint undergoes reverse rotation, the mechanism automatically interrupts the transmission of power to the knee joint, keeping the lower leg in a stable supporting state and completing the supporting phase function.

[0024] 2. This invention utilizes a rope-driven mechanism to control the inward swing of the lower leg. This lateral swing of the lower leg compensates for the distance difference between the foot and the robot body, ensuring that the foot's trajectory remains parallel to the robot body. This prevents foot slippage and guarantees the stability of the robot's movement. Furthermore, this embodiment uses the coordinated operation of an active winding reel, a driven winding reel, a wire rope, and a torsion spring to convert the rotational motion of the hip joint into the lateral swing motion of the lower leg, eliminating the need for a motor and meeting low-energy consumption requirements.

[0025] 3. This invention relies on hip joint movement to drive coordinated movements of the entire leg, and has the advantages of simple structure and low energy consumption.

[0026] 4. The six-legged robot of the present invention can achieve stable movement by using only four drive motors, which greatly reduces the number of motors used and meets the requirements of low energy consumption. Attached Figure Description

[0027] The accompanying drawings, which form part of this invention, are provided to give a further understanding of the invention.

[0028] Figure 1 This is a schematic diagram of the hexapod robot of the present invention.

[0029] Figure 2 This is a schematic diagram of the robot leg structure of the present invention.

[0030] Figure 3 This is a schematic diagram of the robot leg structure of the present invention (with the joint shell removed from the front view).

[0031] Figure 4 This is a schematic diagram of the robot leg structure of the present invention (with the joint shell removed from the back).

[0032] Figure 5 This is a schematic diagram of the hexapod robot of the present invention (with the top plate of the robot body removed).

[0033] Figure 6 This is a top view of the robot leg structure of the present invention.

[0034] Figure 7 This is a front view of the robot leg structure of the present invention.

[0035] Explanation of reference numerals in the attached figures:

[0036] 1. Hip joint; 11. First joint shaft; 12. Joint shell; 2. Thigh; 21. Support rod; 22. Output rod; 23. Crank; 24. Rocker arm; 25. First pin; 26. Second pin; 27. Third pin; 28. Second joint shaft; 3. Lower leg; 4. Foot; 41. Sliding rod; 42. Buffer spring; 5. One-way transmission mechanism; 51. Fixed bevel gear; 52. Driving bevel gear; 53. One-way bearing; 54. Support shaft; 55. Gear shaft; 56. 57. Driven pulley; 58. Synchronous belt; 6. Rope drive mechanism; 61. Driven winding reel; 62. Driven winding reel; 63. Wire rope; 64. Torsion spring; 7. Machine body; 8. First drive mechanism; 81. First drive motor; 82. First worm gear; 83. First worm; 84. First sprocket; 85. Second sprocket; 86. First chain; 9. Second drive mechanism; 91. Third sprocket; 92. Fourth sprocket; 93. Second chain; 94. Second drive motor. Detailed Implementation

[0037] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0038] Example 1:

[0039] See Figure 1 and Figure 5This embodiment of a low-power unidirectional transmission hexapod robot includes a body 7, a first drive mechanism 8, a second drive mechanism 9, and six leg structures. The six leg structures are symmetrically arranged on the left and right sides of the body 7, and the leg structures on each side are respectively designated as front leg, middle leg, and hind leg from front to back. There are two first drive mechanisms 8, which are symmetrically arranged inside the body 7, and each first drive mechanism 8 drives the front leg and hind leg on the same side. There are two second drive mechanisms 9, which are symmetrically arranged inside the body 7, and each second drive mechanism 9 drives the middle leg on the same side.

[0040] See Figure 2 , Figure 3 and Figure 4 The leg structure in this embodiment is mainly used for robot support and movement. It includes a hip joint 1, thigh 2, knee joint, lower leg 3, and foot 4 connected in sequence, as well as a one-way transmission mechanism 5 for controlling the gait of the lower leg 3 and a rope drive mechanism 6 for driving the lower leg 3 to swing laterally. The thigh 2 adopts a deformable four-bar linkage. When the lower leg 3 is about to step forward, the hip joint 1 is driven to rotate forward, and at the same time, the hip joint 1 drives the thigh 2 to deform through the transmission of the one-way transmission mechanism 5, so that the thigh 2 drives the lower leg 3 to complete the lifting and lowering swing phase action, thereby realizing the forward stepping of the lower leg 3. When the lower leg 3 pushes off the ground backward, the hip joint 1 is driven to rotate in the opposite direction. At this time, the one-way transmission mechanism 5 does not transmit motion, and the shape of the thigh 2 remains unchanged, so that the foot 4 always maintains contact with the ground and is in the support phase state of pushing off the ground; at the same time, the hip joint 1 drives the lower leg 3 to swing laterally through the transmission of the rope drive mechanism 6, so that the movement trajectory of the foot 4 is parallel to the body 7, avoiding the problem of the foot 4 slipping.

[0041] This embodiment introduces a one-way transmission mechanism 5, utilizing its unidirectional power transmission characteristic to achieve coordinated control between the hip joint 1 and the knee joint. Specifically, when the hip joint 1 undergoes forward rotation, the one-way transmission mechanism 5 effectively transmits power to the knee joint, thereby driving the lower leg 3 to complete the upward and downward swinging phase movements. When the hip joint 1 undergoes reverse rotation, the mechanism automatically interrupts the power transmission to the knee joint, keeping the lower leg 3 in a stable support state and completing the support phase function. Simultaneously, the design of the rope-driven mechanism 6 enables the lateral swinging of the lower leg 3, preventing foot slippage. This embodiment relies on the movement of the hip joint 1 to drive the coordinated movement of the entire leg, offering advantages such as simple structure and low energy consumption.

[0042] It should be noted that since the robot's left and right legs are arranged symmetrically, the forward rotation mentioned here can be either clockwise or counterclockwise. The specific direction of rotation depends on the installation position of the leg structure. When the leg structure is on the left, the forward rotation is clockwise, and the reverse rotation is counterclockwise; conversely, when the leg structure is on the right, the forward rotation is counterclockwise, and the reverse rotation is clockwise. The following embodiment uses the left leg structure as an example.

[0043] See Figure 3 and Figure 4 In this embodiment, the hip joint 1 includes a first joint shaft 11 and a joint housing 12. The joint housing 12 is rotatably connected to the robot body 7 via the first joint shaft 11, and the first joint shaft 11 is fixedly connected to the joint housing 12. The thigh 2 is composed of a support rod 21, an output rod 22, a crank 23, and a rocker arm 24 connected end to end. Specifically, one end of the support rod 21 is fixed to the outer wall of the joint housing 12, and the other end extends laterally; one end of the output rod 22 is rotatably mounted to the extended end of the support rod 21 via a first pin 25. Two rockers 24 and two cranks 23 are provided, arranged side by side. The other end of the output rod 22 is rotatably connected to one end of the two rockers 24 via a second joint shaft 28 of the knee joint; the other ends of the two rockers 24 are respectively connected to one end of the two cranks 23 via a second pin 26. The other ends of the two cranks 23 are mounted on the joint housing 12 via a third pin 27. One end of the lower leg 3 is fitted onto the second joint axis 28 and can rotate with the second joint axis 28; the other end of the lower leg 3 extends toward the ground, and the foot 4 is connected to the extended end of the lower leg 3.

[0044] When the first joint axis 11 (hip joint 1) is driven to rotate clockwise, the joint housing 12 rotates in the same direction, and through the cooperation of the one-way transmission mechanism 5, drives the third pin 27 and crank 23 to rotate clockwise. The crank 23 further pulls the output rod 22 clockwise upward through the rocker arm 24 and the second joint axis 28, thereby realizing the lifting action of the lower leg 3. Subsequently, the output rod 22 rotates clockwise downward, and the lower leg 3 descends accordingly, completing the stepping action. When the lower leg 3 touches the ground, the first joint axis 11 (hip joint 1) rotates counterclockwise, and the joint housing 12 rotates in the opposite direction accordingly. At this time, the one-way transmission mechanism 5 does not transmit motion, the thigh 2 remains unchanged, and the foot is always in contact with the ground. Driven by the reverse rotation of the hip joint 1, the body 7 can move forward, and at this time the foot is in a pushing-off state, thereby propelling the robot forward as a whole.

[0045] See Figure 3 and Figure 4The one-way transmission mechanism 5 in this embodiment includes a fixed bevel gear 51, a driving bevel gear 52, a one-way bearing 53, a support shaft 54, a gear shaft 55, and a first flexible transmission assembly. The support shaft 54 ​​is coaxially arranged with the first joint shaft 11. One end of the support shaft 54 ​​is fixed to the bottom plate of the body 7, and the other end passes through the joint housing 12 and is fixedly connected to the fixed bevel gear 51 so that the fixed bevel gear 51 remains stationary. The gear shaft 55 is arranged inside the joint housing 12, and both ends of the gear shaft 55 are rotatably mounted on the inner side wall of the joint housing 12 through bearings. The driving bevel gear 52 is fitted onto the gear shaft 55 through the one-way bearing 53 and meshes with the fixed bevel gear 51. The first flexible transmission assembly connects the gear shaft 55 and the third pin 27.

[0046] Among them, such as Figure 3 and Figure 4 As shown, the first flexible transmission assembly includes a driving pulley 56, a driven pulley 57, and a synchronous belt 58. The driving pulley 56 is mounted on the gear shaft 55 and can rotate with the gear shaft 55; the driven pulley 57 is mounted on the third pin 27; and the synchronous belt 58 surrounds the driving pulley 56 and the driven pulley 57 and is tensioned.

[0047] When the joint housing 12 rotates clockwise, the driving bevel gear 52 rotates clockwise along with the joint housing 12 and, under the action of the fixed bevel gear 51, rotates on its own axis. The driving bevel gear 52 drives the driving pulley 56 to rotate clockwise through the one-way bearing 53 and the gear shaft 55. The driving pulley 56 drives the driven pulley 57 to rotate clockwise through the synchronous belt 58. The driven pulley 57 drives the third pin shaft 27 to rotate clockwise, thereby driving the crank 23 to rotate clockwise, causing the thigh 2 to deform. When the joint housing 12 rotates counterclockwise, the driving bevel gear 52 rotates counterclockwise along with the joint housing 12 and, under the action of the fixed bevel gear 51, rotates on its own axis. Since the one-way bearing 53 can only transmit power to one side, the outer ring of the one-way bearing 53 rotates freely with the driving bevel gear 52 and does not transmit the rotational motion to the inner ring. At this time, the gear shaft 55 remains stationary, the first flexible transmission component does not transmit motion, and the shape of the thigh 2 remains unchanged.

[0048] As can be seen, in this embodiment, the joint housing 12, fixed bevel gear 51, driving bevel gear 52, gear shaft 55, and the first flexible transmission assembly work together for transmission. Combined with the unidirectional transmission characteristics of the one-way bearing 53, the forward rotation of the hip joint 1 is converted into the swinging of the crank 23 and rocker arm 24 in the thigh 2, thereby driving the lower leg 3 to achieve the lifting and lowering movements. When the hip joint 1 rotates in the reverse direction, the transmission chain is broken by the one-way bearing 53, thus ensuring that the swinging phase and the support phase of the leg can be performed in an orderly and alternating manner during the complete movement cycle.

[0049] See Figure 2 , Figure 3 and Figure 4The rope-driven mechanism 6 in this embodiment includes a driving reel 61, a driven reel 62, a wire rope 63, and a torsion spring 64. The driving reel 61 is mounted on the first joint shaft 11 and keyed to the first joint shaft 11. The driven reel 62 is mounted on the second joint shaft 28 and keyed to the second joint shaft 28. One end of the wire rope 63 is wound around the driving reel 61, and the other end is wound in the opposite direction around the driven reel 62. The torsion spring 64 is mounted on the second joint shaft 28, with one end connected to the driven reel 62 and the other end connected to the rocker arm 24. The torsion spring 64 is used to reset the driven reel 62.

[0050] When the hip joint 1 is driven to rotate clockwise, the active winding wheel 61 rotates clockwise with the first joint axis 11 to wind the wire rope 63. The driven winding wheel 62 releases the wire rope 63 against the elastic force of the torsion spring 64. The second joint axis 28 rotates with the driven winding wheel 62, causing the lower leg 3 to swing laterally outward. When the hip joint 1 is driven to rotate counterclockwise, the active winding wheel 61 rotates counterclockwise with the first joint axis 11, releasing the wire rope 63. The driven winding wheel 62 rotates under the restoring force of the torsion spring 64 and winds the wire rope 63. At the same time, the second joint axis 28 rotates with the driven winding wheel 62, causing the lower leg 3 to swing laterally inward. Since the hip joint 1 drives the entire leg to perform circular motion, when the hip joint 1 rotates clockwise, the lower leg 3 lifts up and leaves the ground. At this time, the movement trajectory of the foot 4 does not affect the stability of the robot's movement. When the hip joint 1 rotates counterclockwise, since the foot 4 is always in contact with the ground, the foot 4 will gradually move away from the body 7 as the hip joint 1 rotates, causing relative movement with the ground and resulting in slippage of the foot 4, which affects the stability of the robot's movement. Therefore, this embodiment uses the design of the rope drive mechanism 6 to control the lateral swing of the lower leg 3. The lateral swing of the lower leg 3 compensates for the distance difference between the foot 4 and the body 7, so that the movement trajectory of the foot 4 is always parallel to the body 7, thereby avoiding the slippage problem of the foot 4 and ensuring the stability of the robot's movement. In addition, this embodiment uses the coordinated operation of the active winding wheel 61, the driven winding wheel 62, the wire rope 63 and the torsion spring 64 to convert the rotational motion of the hip joint 1 (first joint axis 11) into the lateral swinging motion of the lower leg 3, eliminating the need for a motor and meeting the requirements of low energy consumption.

[0051] It should be noted that the wire ropes 63 in the left front leg, left rear leg, and right middle leg are wound in opposite directions on the driving reel 61 and driven reel 62, while the wire ropes 63 in the right front leg, right rear leg, and left middle leg are wound in the same direction on the driving reel 61 and driven reel 62. Specifically, as... Figure 5As shown, one end of the wire rope 63 in the left front leg and left rear leg is wound clockwise onto the drive reel 61, and the other end is wound counterclockwise onto the driven reel 62; one end of the wire rope 63 in the right middle leg is wound counterclockwise onto the drive reel 61, and the other end is wound clockwise onto the driven reel 62. Both ends of the wire rope 63 in the right front leg and right rear leg are wound clockwise onto the drive reel 61 and the driven reel 62; the wire rope 63 in the left middle leg is wound counterclockwise onto the drive reel 61 and the driven reel 62. The reason for this design is that, for the left leg structure, the hip joint swings forward (going stroke) and backward (return stroke). During the backward swing of the hip joint, the foot gradually moves away from the fuselage. Therefore, the reverse winding of the wire rope 63 allows the foot to gradually move inward, achieving a foot movement trajectory parallel to the fuselage. For the right leg structure, the hip joint swings backward as the outward stroke and forward as the return stroke. During the backward swing of the hip joint, the foot gradually approaches the fuselage. Therefore, the steel wire rope is wound in the same direction so that the foot gradually moves outward, making the movement trajectory of the foot parallel to the fuselage.

[0052] See Figure 2 , Figure 3 and Figure 4 In this embodiment, the foot 4 also includes a sliding rod 41, which is slidably connected to the lower leg 3. A buffer spring 42 is sleeved on the sliding rod 41. The foot 4 of the robot in this embodiment adopts an elastic design, which provides landing cushioning for the robot while ensuring that the six leg structures of the robot are always in contact with the ground on uneven ground.

[0053] See Figure 5 The first drive mechanism 8 in this embodiment includes a first drive motor 81, a worm gear assembly, and a second flexible transmission assembly. Both the worm gear assembly and the second flexible transmission assembly are provided in two sets, one set corresponding to the front leg and the other set corresponding to the rear leg. Each worm gear assembly includes a first worm wheel 82 and a first worm 83 meshing together. Each second flexible transmission assembly includes a first sprocket 84, a second sprocket 85, and a first chain 86. The first worm 83 in both sets of worm gear assemblies is coaxially connected to the motor shaft of the first drive motor 81. The two first worm wheels 82 are rotatably mounted on the body 7 and coaxially connected to the corresponding first sprocket 84. The second sprocket 85 is fitted onto the first joint shaft 11 in the corresponding leg structure. The first chain 86 surrounds the first sprocket 84 and the second sprocket 85 and is tensioned.

[0054] See Figure 5The second drive mechanism 9 in this embodiment includes a second drive motor 94 and a third flexible transmission assembly. The third flexible transmission assembly includes a third sprocket 91, a fourth sprocket 92 and a second chain 93. The third sprocket 91 is connected to the motor shaft of the second drive motor 94. The fourth sprocket 92 is fitted onto the first joint shaft 11 in the corresponding leg structure. The second chain 93 surrounds the third sprocket 91 and the fourth sprocket 92 and is tensioned.

[0055] When the first drive motor 81 drives the two first sprockets 84 of the same group to rotate through the corresponding two sets of worm gear assemblies, the first chain 86 drives the two second sprockets 85 to rotate, and the two second sprockets 85 drive the first joint shaft 11 connected to them to rotate. Thus, the drive control of the front and rear legs is achieved through a single first drive motor 81. When the second drive motor 94 drives the third sprocket 91 to rotate, the second chain 93 drives the fourth sprocket 92 to rotate, and the fourth sprocket 92 drives the first joint shaft 11 connected to it to rotate, thereby achieving the drive control of the middle leg. This embodiment achieves the drive of all six legs with only four drive motors, reducing the number of motors used, greatly reducing the energy consumption of the hexapod robot, simplifying the overall structure and control program, and improving the stability of the hexapod robot's movement.

[0056] Furthermore, in this embodiment, the left front leg, left hind leg, and right middle leg move in a synchronized sequence, as do the right front leg, right hind leg, and left middle leg. When the two first drive motors 81 rotate clockwise and the two second drive motors 94 rotate counterclockwise, the left front leg, left hind leg, and right middle leg step forward. Simultaneously, the feet 4 of the right front leg, right hind leg, and left middle leg contact the ground and push off, propelling the robot forward. When the left front leg, left hind leg, and right middle leg complete a swing phase, and the right front leg, right hind leg, and left middle leg complete a support phase, the two first drive motors 81 rotate counterclockwise, and the two second drive motors 94 rotate clockwise. The right front leg, right hind leg, and left middle leg step forward, and the feet 4 of the left front leg, left hind leg, and right middle leg contact the ground and push off, propelling the robot forward. This cycle repeats continuously, achieving a triangular gait for the hexapod robot and increasing its stability.

[0057] How a six-legged robot works:

[0058] Let's take the example of stepping forward with the left front leg, left back leg, and right middle leg, while supporting the ground with the right front leg, right back leg, and left middle leg.

[0059] Forward movement: Two first drive motors 81 rotate clockwise, and two second drive motors 94 rotate counterclockwise. The first joint shafts 11 of the left front leg and left rear leg rotate clockwise, while the first joint shaft 11 of the right middle leg rotates counterclockwise. The joint housings 12 on both sides rotate in the same direction. Simultaneously, the driving bevel gear 52 of the left leg rotates clockwise under the action of the fixed bevel gear 51, along with the joint housing 12. The driving bevel gear 52 drives the driving pulley 56 to rotate clockwise via the one-way bearing 53 and gear shaft 55. The driving pulley 56 drives the driven pulley 57 to rotate clockwise via the synchronous belt 58. The driven pulley 57 drives the third pin shaft 27 to rotate clockwise, thereby driving the crank 23 to rotate clockwise. The crank 23 further pulls the output rod 22 clockwise upward via the rocker arm 24 and the second joint shaft 28, thus lifting the left lower leg 3. Subsequently, the output rod 22 rotates clockwise downward, causing the left lower leg 3 to descend. The right middle leg moves in the opposite direction, while the left front leg, left rear leg, and right middle leg complete the stepping motion. Simultaneously, the active winding wheels 61 of the left front and left rear legs rotate clockwise with the first joint axis 11 to wind the steel wire rope 63. The driven winding wheel 62 releases the steel wire rope 63 against the elastic force of the torsion spring 64. The second joint axis 28 rotates with the driven winding wheel 62, causing the lower leg 3 to swing laterally outward. Similarly, the right middle leg also swings laterally outward; that is, the left front leg, left rear leg, and right middle leg swing laterally outward while stepping.

[0060] The first joint axis 11 of the right foreleg and right hindleg rotates clockwise, while the first joint axis 11 of the left middle leg rotates counterclockwise, causing the joint shells 12 on both sides to rotate in the same direction. Simultaneously, the active bevel gear 52 of the right leg rotates clockwise under the action of the fixed bevel gear 51, as the joint shell 12 rotates. Since the one-way bearing 53 can only transmit power to one side, its outer ring idles with the active bevel gear 52 without transmitting rotational motion to the inner ring, and the gear shaft 55 remains stationary. The thigh 2 maintains its shape, and the foot remains in contact with the ground. The foot of the left middle leg also remains in contact with the ground. Driven by the counter-rotation of the hip joint 1, the body 7 moves forward, with the foot in a pushing-off state, propelling the robot forward. Simultaneously, the active winding wheels 61 of the right front leg and right hind leg rotate clockwise with the first joint shaft 11, winding up the wire rope 63. The driven winding wheel 62 releases the wire rope 63 against the elastic force of the torsion spring 64. The second joint shaft 28 rotates with the driven winding wheel 62, causing the lower leg 3 to swing laterally outward. This causes the foot 4 to gradually move away from the fuselage, and the movement trajectory of the foot 4 remains parallel to the fuselage 7, preventing the foot from slipping.

[0061] Turning process: When the speed of the first drive motor 81 is less than the speed of the second drive motor 94, the stride length of the left front leg and left hind leg is less than the stride length of the right middle leg, and the hexapod robot turns to the left. Conversely, when the speed of the first drive motor 81 is greater than the speed of the second drive motor 94, the stride length of the left front leg and left hind leg is greater than the stride length of the right middle leg, and the hexapod robot turns to the right. That is, the hexapod robot's turning is achieved through differential rotation.

[0062] Example 2:

[0063] This embodiment provides a method for correcting the foot trajectory of a low-power, unidirectional transmission hexapod robot, including the following correction process:

[0064] 1. Definition of coordinate system:

[0065] To clarify the motion mechanism of the robot described in this invention, a kinematic model of the single-leg system is established. For example... Figure 6 , Figure 7 As shown, the center of hip joint rotation is set as the origin of the local coordinate system. , The axis is along the robot's direction of movement, with forward being positive. The axis is vertical, with upward being positive. The axis is determined according to the right-hand rule. The angle of hip joint swing is defined as forward swing as positive and backward swing as negative.

[0066] 2. Transmission chain and input signal model:

[0067] The robot's single-leg movement originates from the rotation of a motor. Let the motor's output speed be... After passing through the worm gear (reduction ratio) ) and chain drive (transmission ratio) After that, the first joint axis 11 of the hip joint 1 is rotated. The total reduction ratio of the system is... for:

[0068]

[0069] Hip joint swing angular velocity The relationship with the motor speed is as follows:

[0070]

[0071] 3. Knee-hip joint line-driven coupling model:

[0072] This invention utilizes a cable reel and steel wire rope to achieve active following of the hip joint by the knee joint. Parameter definitions, The radius of the active winding reel 61 at the hip joint. The radius of the driven winding reel 62 at the knee joint. Let be the swing angle of the lower leg axis relative to the vertical direction of the knee joint, defined as counterclockwise rotation as positive and clockwise rotation as negative (initial swing angle is ). (Related to the initial installation position of the robot's lower leg).

[0073] According to the principle of linear actuation, the length of the wire rope is conserved. When the hip joint angle... At that time, knee joint angle Satisfy linear relationship That is, the knee joint rotation angle is:

[0074]

[0075] in The geometric coupling coefficient is... This is the direction coefficient.

[0076] 4. Equation of foot movement trajectory and conditions for non-slippage in the support phase:

[0077] This invention employs a bevel gear coupled with a one-way bearing (one-way transmission mechanism 5) to drive a four-bar linkage (thigh 2), achieving an approximately linear motion trajectory between the leg raising / lowering phase and the foot end in the supporting phase. Let the number of teeth on the fixed bevel gear be... The number of teeth on the driving bevel gear is The synchronous belt drive ratio is .

[0078] Define the logic selection function for a one-way bearing. :

[0079]

[0080] Crank input angle of a four-bar linkage The rate of change of hip joint swing angle is:

[0081]

[0082] Within the swing phase interval, the input angle can be obtained by integration:

[0083]

[0084] in ; This is the initial angle, which is related to the initial installation position.

[0085] Establish a four-bar vector loop model. The length of the robot's lower leg is given by the distance between the first and third pins. That is, the distance between the pin holes at both ends of the support rod, and the direction angle of the support rod. Set 0° as the reference point; the crank is fixed to the driven pulley, and the distance between the second and third pins is... As the input to the four-bar linkage, the distance between the pin holes at both ends of the crank is the crank input angle. The distance between the second pin and the second joint pin is That is, the distance between the pin holes at both ends of the rocker arm 24, and the rocker arm direction angle is... The distance between the first pin and the second joint pin is That is, the distance between the pin holes at both ends of the output rod, and the output angle of the output rod is... .

[0086] The four-bar linkage forms a closed vector polygon, and the closed-loop vector equations are constructed as follows:

[0087]

[0088] in, Represents the rod length vector, in Figure 7 In the robot's leg configuration shown, the side closer to the hip joint is defined as the proximal end, and the side farther from the hip joint as the distal end. The vector direction is from the proximal end to the distal end. The vector equation (7) is then applied... shaft and Projecting the axes, we obtain a system of scalar equations:

[0089]

[0090] Add the squares of both sides of the above equation together, and use... eliminate :

[0091]

[0092] Expanding and rearranging the above equation, we obtain the information about the output angle. The trigonometric equations:

[0093]

[0094] In the formula:

[0095]

[0096] Using the half-width substitution formula, let ,but Substituting into (10), the output angle can be obtained. for:

[0097]

[0098] Thus, the output angle was obtained. Regarding the input angle Analytical functions:

[0099]

[0100] The position of the robot's feet in three-dimensional space can be obtained based on geometric relationships:

[0101]

[0102] in, This is the distance from the center of hip joint rotation to the third pivot pin.

[0103] Substituting equations (3), (6), and (12) into the above equation, we can obtain the analytical expression for the three-dimensional spatial foot movement trajectory of the hexapod robot:

[0104]

[0105] Substituting equation (4) into the above equation, we can obtain the corresponding trajectory of the foot end of the swing phase as follows:

[0106]

[0107] Similarly, substituting equation (4) into equation (14) yields the following support phase foot trajectory:

[0108]

[0109] To ensure the robot does not slip at the foot end of the support phase, i.e., the foot trajectory is approximately straight, the lateral distance at the foot end must be constant. ,right about Differentiation yields:

[0110]

[0111] in Further simplification of the above formula yields:

[0112]

[0113] consider Since the angle is not 90° within the travel range, we can conclude that:

[0114]

[0115] This yields the required geometric coupling coefficient of the winding reel to prevent slippage at the support foot. However, due to... As a design-defined value, it cannot be adjusted. Since the movement changes in real time, the maximum swing angle during the gait cycle is selected to achieve an "approximately straight" anti-slip effect at the foot. Parameter matching is performed for the operating conditions at the location. Specifically, the design of the geometric coupling coefficient of the winding reel must meet the following engineering approximation conditions:

[0116]

[0117] in, This is the maximum swing angle of the lower leg axis relative to the vertical direction of the knee joint.

[0118] At the maximum swing angle, the geometric nonlinear effect is strongest, and the tendency for lateral leg slippage is greatest. Choosing this location can limit lateral slippage within a very small range throughout the entire gait cycle, thereby ensuring the straightness of the entire cycle.

[0119] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions created by the present invention, and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions created by the present invention without departing from the essence and scope of the technical solutions created by the present invention.

Claims

1. A low-power unidirectional transmission hexapod robot, characterized in that, The robot comprises a body and six leg structures which are arranged symmetrically on the left and right sides of the body, each leg structure comprising a hip joint, a thigh, a knee joint, a lower leg and a foot which are connected in sequence, and a one-way transmission mechanism for controlling the gait of the lower leg, the thigh being a deformable four-bar linkage mechanism, and the one-way transmission mechanism connecting the thigh and the hip joint; when the hip joint is driven to rotate forward, the thigh is driven to deform through the transmission cooperation of the one-way transmission mechanism, so that the thigh drives the lower leg to complete the swing action of lifting and falling; when the hip joint is driven to rotate reversely, the one-way transmission mechanism does not transmit motion, and the thigh no longer deforms, so that the foot always keeps in contact with the ground and supports the ground; The hip joint comprises a first joint shaft and a joint shell, the joint shell being rotatably installed on the body of the robot through the first joint shaft; the one-way transmission mechanism comprises a fixed bevel gear, a driving bevel gear, a gear shaft, a one-way bearing and a first flexible transmission assembly; the fixed bevel gear is connected to the body and remains stationary; the gear shaft is rotatably installed in the joint shell, the driving bevel gear is sleeved on the gear shaft through the one-way bearing and is in meshing connection with the fixed bevel gear; the first flexible transmission assembly connects the gear shaft and the thigh and is used for power transmission.

2. The low-power unidirectional transmission hexapod robot according to claim 1, characterized in that, The first flexible transmission assembly comprises a driving pulley, a driven pulley and a synchronous belt, the driving pulley is sleeved on the gear shaft and can rotate with the gear shaft; the driven pulley is sleeved on one of the pin shafts of the thigh; the synchronous belt is wound around the driving pulley and the driven pulley and is tensioned.

3. The low-power unidirectional transmission hexapod robot according to claim 1, characterized in that, Further comprising a rope drive mechanism for driving the lateral swing of the lower leg, the rope drive mechanism comprising a driving winding wheel, a driven winding wheel, a steel wire rope and a torsion spring, the driving winding wheel being sleeved on the first joint shaft; the driven winding wheel being sleeved on a second joint shaft of the knee joint; one end of the steel wire rope being wound on the driving winding wheel, and the other end being wound on the driven winding wheel; The torsion spring is sleeved on the second joint shaft and is used for resetting the driven winding wheel.

4. The low-power unidirectional transmission hexapod robot according to claim 1, wherein, The foot is provided with a sliding rod, the foot and the lower leg are slidably connected through the sliding rod, and a buffer spring is sleeved on the sliding rod.

5. The low-power unidirectional transmission hexapod robot according to claim 1, wherein, Further comprising a first driving mechanism and a second driving mechanism, the leg structures on each side are respectively front legs, middle legs and rear legs; the first driving mechanism is provided with two and is arranged symmetrically in the body, each first driving mechanism corresponding to drive the front leg and the rear leg on the same side; the second driving mechanism is provided with two and is arranged symmetrically in the body, each second driving mechanism corresponding to drive the middle leg on the same side.

6. The low-power unidirectional transmission hexapod robot according to claim 5, characterized in that, The first driving mechanism comprises a first driving motor, a worm gear assembly and a second flexible transmission assembly, the worm gear assembly and the second flexible transmission assembly are each provided with two groups, one group of the worm gear assembly and the second flexible transmission assembly corresponding to the front leg, and the other group of the worm gear assembly and the second flexible transmission assembly corresponding to the rear leg; each group of the worm gear assembly comprises a first worm gear and a first worm in meshing connection, and each group of the second flexible transmission assembly comprises a first sprocket, a second sprocket and a first chain; the first worm in the two groups of the worm gear assembly is coaxially connected to the motor shaft of the first driving motor, the two first worm gears are rotatably installed on the body and are coaxially connected with the corresponding first sprocket, the second sprocket is sleeved on the first joint shaft in the corresponding leg structure, and the first chain is wound around the first sprocket and the second sprocket and is tensioned.

7. The low-power unidirectional transmission hexapod robot according to claim 5, wherein, The second driving mechanism comprises a second driving motor and a third flexible transmission assembly, the third flexible transmission assembly comprises a third sprocket, a fourth sprocket and a second chain, the third sprocket is connected to a motor shaft of the second driving motor, the fourth sprocket is sleeved at a first joint shaft in the corresponding leg structure, and the second chain is wound around the third sprocket and the fourth sprocket and is tensioned.

8. A method for correcting the trajectory of a leg end of a low-power unidirectional transmission hexapod robot, characterized in that, The low-power-consumption unidirectional transmission six-legged robot according to claim 3, wherein the foot end trajectory is corrected by setting a winding wheel geometric coupling coefficient, and the winding wheel geometric coupling coefficient is as follows: wherein is the maximum swing angle of the hip joint, is the length of the robot shank; , is the distance between the first pin axis and the third pin axis, is the distance between the first pin axis and the second joint axis, is the distance from the center of rotation of the hip joint to the third pin axis, is the initial angle of the crank input angle; is the direction coefficient, is the maximum swing angle of the shank axis relative to the vertical direction of the knee joint; represents the analytical function of the output angle with respect to the input angle, for has: wherein is the distance between the second pin axis and the third pin axis, is the distance between the second pin axis and the second joint axis.

9. The foot trajectory correction method for a low-power consumption unidirectional transmission hexapod robot according to claim 8, characterized in that, direction coefficient by the linear relationship between the hip joint rotation angle and the knee joint rotation angle is determined, i.e. wherein is a geometric coupling coefficient, is a radius of the active capstan at the hip joint, is a radius of the driven capstan at the knee joint.

Images