Low-power-consumption one-way transmission hexapod robot and foot end track correction method thereof

Abstract

The invention discloses a low-power-consumption one-way transmission hexapod robot and a foot end track correction method thereof, and belongs to the field of robot design. The problems that an existing robot is high in energy consumption, heavy in structure, complex in control, high in cost, low in reliability and the like are solved. The hip joint, the thigh, the knee joint, the shank and the foot are connected in sequence, the one-way transmission mechanism is used for controlling the gait of the shank, the thigh is a deformable four-bar mechanism, and the one-way transmission mechanism is connected with the thigh and the hip joint; when the hip joint is driven to rotate in the forward direction, the thigh is driven to deform through transmission cooperation of the one-way 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 one-way transmission mechanism does not transmit motion at the moment, the thighs do not deform any more, and therefore the feet are always kept in the supporting phase of making contact with the ground and stepping on the ground. The system is mainly used for executing tasks such as complex environment exploration, disaster rescue and planet exploration.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of robot design, in particular to a low-power one-way transmission hexapod robot and a foot end trajectory correction method thereof. BACKGROUND

[0002] Hexapod robots, which imitate the six-legged movement of insects, have excellent terrain adaptability, good static stability, and flexible gait, and thus have great application potential in complex environment exploration, disaster rescue, and planetary exploration. Compared with biped or quadruped robots, hexapod robots can walk stably on uneven ground through the coordinated cooperation of multiple legs.

[0003] At present, mainstream hexapod robots usually adopt a series joint type leg structure. Each leg is generally designed as a motion mechanism with three degrees of freedom, corresponding to the pitch / yaw of the hip joint, the pitch of the knee joint, and the like, to realize accurate positioning and flexible movement of the foot end in three-dimensional space. In order to realize independent control of the three degrees of freedom, each leg usually needs to be configured with three independent drive motors. Therefore, a complete hexapod robot needs at least 18 drive motors. Since the drive motor is the main energy consumption unit of the robot, 18 motors work simultaneously or alternately, resulting in huge power consumption of the whole machine, greatly shortened endurance time, and difficulty in meeting the demand for long-time operation. At the same time, it also increases the control difficulty. In addition, a large number of motors and their attached structures cause the weight and volume of the robot body to increase significantly. This not only increases the manufacturing cost, but also further increases the power consumption. In summary, the existing hexapod robot has a series of problems such as high energy consumption, heavy structure, complex control, high cost, and relatively low reliability. SUMMARY

[0004] Therefore, the present application provides a low-power one-way transmission hexapod robot and a foot end trajectory correction method thereof, which utilizes the one-way power transmission characteristics of the one-way transmission mechanism to convert the rotary motion of the hip joint into the motion of the thigh and the shank, and eliminates the use of the knee joint motor, thereby meeting the requirement of low energy consumption.

[0005] To solve the above technical problems, the technical scheme adopted by the present application 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] Further, 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 both provided with two groups, one group of the worm gear assembly and the second flexible transmission assembly correspond to the front leg, and the other group of the worm gear assembly and the second flexible transmission assembly correspond to the rear leg; each group of the worm gear assembly comprises a first worm gear and a first worm in mesh 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 rotationally installed on the fuselage and coaxially connected with the corresponding first sprocket, the second sprocket is sleeved at 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.

[0013] Further, 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 with the motor shaft of the second driving motor, the fourth sprocket is sleeved at the 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.

[0014] In the second aspect, the application provides a foot end trajectory correction method for a low-power one-way transmission hexapod robot, which is used for the low-power one-way transmission hexapod robot in the first aspect, and the foot end trajectory is corrected by setting a winding wheel geometric coupling coefficient, and the winding wheel geometric coupling coefficient is set as follows:

[0015]

[0016] wherein, is the maximum swing angle of the hip joint, is the length of the robot calf; , is the distance between the first pin shaft and the third pin shaft, is the distance between the first pin shaft and the second joint shaft, is the distance from the rotation center of the hip joint to the third pin shaft, is the initial angle of the input angle of the main drive crank, is the direction coefficient, is the maximum swing angle of the calf axis relative to the vertical direction of the knee joint;

[0017] represents an analytical function of the output angle with respect to the input angle, and for there is:

[0018]

[0019]

[0020] wherein, 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 5The low-power one-way transmission six-legged robot of the embodiment comprises a body 7, a first driving mechanism 8, a second driving mechanism 9 and six leg structures which are symmetrically arranged on the left and right sides of the body 7. The leg structure on each side is provided with a front leg, a middle leg and a rear leg from front to back. The first driving mechanism 8 is provided with two and symmetrically arranged in the body 7. Each first driving mechanism 8 drives the front leg and the rear leg on the same side. The second driving mechanism 9 is provided with two and symmetrically arranged in the body 7. Each second driving mechanism 9 drives the middle leg on the same side.

[0040] Referring to Figure 2 , Figure 3 and Figure 4 , the leg structure of the embodiment is mainly used for supporting and advancing the robot. It comprises a hip joint 1, a thigh 2, a knee joint, a shank 3 and a foot 4 which are sequentially connected, a one-way transmission mechanism 5 for controlling the gait of the shank 3 and a rope driving mechanism 6 for driving the lateral swing of the shank 3. The thigh 2 adopts a deformable four-bar linkage mechanism. When the shank 3 steps 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 cooperation of the one-way transmission mechanism 5, so that the thigh 2 drives the shank 3 to complete the swing of lifting and falling, thereby realizing the forward step of the shank 3. When the shank 3 steps backward, the hip joint 1 is driven to rotate reversely, at this time, the one-way transmission mechanism 5 does not transmit motion, and the thigh 2 keeps unchanged, so that the foot 4 always keeps in contact with the ground and in the supporting state of stepping on the ground. At the same time, the hip joint 1 drives the shank 3 to swing laterally through the transmission cooperation of the rope driving mechanism 6, so that the motion track of the foot 4 is parallel to the body 7, avoiding the problem of slipping of the foot 4.

[0041] The embodiment introduces the one-way transmission mechanism 5, utilizes the characteristic of one-way transmission of power, and realizes the coordinated control between the motion of the hip joint 1 and the knee joint. Specifically, when the hip joint 1 rotates forward, the one-way transmission mechanism 5 can effectively transmit power to the knee joint, thereby driving the shank 3 to complete the swing of lifting and falling. When the hip joint 1 rotates reversely, the mechanism automatically interrupts the transmission of power to the knee joint, so that the shank 3 keeps in the stable supporting state and completes the supporting function. At the same time, the lateral swing of the shank 3 is completed through the design of the rope driving mechanism 6, avoiding the problem of slipping of the foot end. The embodiment can drive the whole leg to coordinate the motion by the motion of the hip joint 1, and has the advantages of simple structure and low energy consumption.

[0042] It should be noted that, since the left leg and the right leg of the robot are symmetrically arranged, the forward rotation mentioned here can be clockwise rotation or counterclockwise rotation, and the specific rotation direction is related to the installation position of the leg structure. When the leg structure is on the left side, the forward rotation here is clockwise movement, and the reverse rotation is counterclockwise movement. Conversely, when the leg structure is on the right side, the forward rotation here is counterclockwise movement, and the reverse rotation is clockwise movement. The following embodiment takes the leg structure on the left side as an example for description.

[0043] Referring to Figure 3 and Figure 4 , the hip joint 1 of the embodiment comprises a first joint shaft 11 and a joint shell 12. The joint shell 12 is rotatably connected to the robot body 7 through the first joint shaft 11, and the first joint shaft 11 is fixedly connected with the joint shell 12. The thigh 2 is composed of a support rod 21, an output rod 22, a crank 23 and a rocker 24 connected in sequence from head to tail. Specifically, the support rod 21 is fixed at one end to the outer side wall of the joint shell 12 and extends to the side at the other end; the output rod 22 is rotatably installed at the extended end of the support rod 21 through a first pin shaft 25. The rocker 24 and the crank 23 are both provided with two, arranged in front and back side by side. The other end of the output rod 22 is rotatably connected with one end of the two rockers 24 through a second joint shaft 28 of the knee joint; the other end of the two rockers 24 is connected with one end of the two cranks 23 through a second pin shaft 26 respectively. The other end of the two cranks 23 is installed on the joint shell 12 through a third pin shaft 27. One end of the lower leg 3 is sleeved on the second joint shaft 28 and can rotate with the second joint shaft 28; the other end of the lower leg 3 extends to the ground, and the foot 4 is connected to the extended end of the lower leg 3.

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

[0045] Referring to Figure 3 and Figure 4The one-way transmission mechanism 5 of the embodiment comprises 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 on the bottom plate of the fuselage 7, and the other end is fixedly connected with the fixed bevel gear 51 through the joint shell 12, so that the fixed bevel gear 51 remains stationary. The gear shaft 55 is arranged in the joint shell 12, both ends of the gear shaft 55 are rotatably installed at the inner side wall of the joint shell 12 through bearings, the driving bevel gear 52 is sleeved on the gear shaft 55 through the one-way bearing 53 and is meshingly connected with the fixed bevel gear 51. The first flexible transmission assembly connects the gear shaft 55 and the third pin shaft 27.

[0046] As shown in Figure 3 and Figure 4 , the first flexible transmission assembly comprises a driving pulley 56, a driven pulley 57 and a synchronous belt 58, the driving pulley 56 is sleeved on the gear shaft 55 and can rotate with the gear shaft 55; the driven pulley 57 is sleeved on the third pin shaft 27; and the synchronous belt 58 is wound around the driving pulley 56 and the driven pulley 57 and is tensioned.

[0047] When the joint shell 12 rotates clockwise, the driving bevel gear 52 rotates clockwise by the action of the fixed bevel gear 51 while rotating with the joint shell 12, 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, so that the thigh 2 is deformed. When the joint shell 12 rotates counterclockwise, the driving bevel gear 52 rotates counterclockwise by the action of the fixed bevel gear 51 while rotating with the joint shell 12, since the one-way bearing 53 can only transmit power to one side, the outer ring of the one-way bearing 53 idles with the driving bevel gear 52, and the rotation is not transmitted to the inner ring, at this time the gear shaft 55 remains stationary, the first flexible transmission assembly does not transmit motion, and the thigh 2 remains unchanged.

[0048] It can be seen that in the embodiment, the joint shell 12, the fixed bevel gear 51, the driving bevel gear 52, the gear shaft 55 and the first flexible transmission assembly are cooperatively driven, and the forward rotation of the hip joint 1 is converted into the swing of the crank 23 and the rocker 24 in the thigh 2 part in combination with the one-way transmission characteristic of the one-way bearing 53, so as to drive the lower leg 3 to realize the actions of lifting up and falling down. When the hip joint 1 reversely rotates, the transmission chain is disconnected by the one-way bearing 53, so as to ensure that the swing phase and the support phase can be orderly and alternately performed in the complete motion cycle of the leg.

[0049] Referring to Figure 2 , Figure 3 and Figure 4The rope driving mechanism 6 of the embodiment includes a driving winding wheel 61, a driven winding wheel 62, a steel wire rope 63 and a torsion spring 64. The driving winding wheel 61 is sleeved on the first joint shaft 11 and is connected with the first joint shaft 11 by a key. The driven winding wheel 62 is sleeved on the second joint shaft 28 and is connected with the second joint shaft 28 by a key. One end of the steel wire rope 63 is wound on the driving winding wheel 61, and the other end is reversely wound on the driven winding wheel 62. The torsion spring 64 is sleeved on the second joint shaft 28, one end of the torsion spring 64 is connected with the driven winding wheel 62, and the other end is connected with the rocker 24. The torsion spring 64 is used for resetting the driven winding wheel 62.

[0050] When the hip joint 1 is driven to rotate in the clockwise direction, the driving winding wheel 61 rotates clockwise with the first joint shaft 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 shaft 28 rotates with the driven winding wheel 62 to swing the lower leg 3 laterally outward. When the hip joint 1 is driven to rotate in the counterclockwise direction, the driving winding wheel 61 rotates counterclockwise with the first joint shaft 11 to release the steel wire rope 63, the driven winding wheel 62 rotates to wind the steel wire rope 63 under the rebounding force of the torsion spring 64, and at the same time, the second joint shaft 28 rotates with the driven winding wheel 62 to swing the lower leg 3 laterally inward. Since the hip joint 1 drives the whole leg to make a circular motion, when the hip joint 1 rotates clockwise, the lower leg 3 is lifted and separated from the ground, and at this time, the movement track of the foot 4 does not affect the stability of the robot. When the hip joint 1 rotates counterclockwise, since the foot 4 is always in contact with the ground, the foot 4 gradually moves away from the body 7 with the rotation of the hip joint 1, and the relative motion between the foot 4 and the ground occurs, which causes the foot 4 to slip and affects the stability of the robot. Therefore, the embodiment controls the lateral swing of the lower leg 3 through the design of the rope driving mechanism 6, compensates the distance difference between the foot 4 and the body 7 through the lateral swing of the lower leg 3, so that the movement track of the foot 4 is always parallel to the body 7, thereby avoiding the slipping problem of the foot 4 and ensuring the stability of the robot motion. In addition, the embodiment converts the rotary motion of the hip joint 1 (the first joint shaft 11) into the lateral swing motion of the lower leg 3 through the cooperation of the driving winding wheel 61, the driven winding wheel 62, the steel wire rope 63 and the torsion spring 64, and the use of the motor is omitted, thereby meeting the requirement of low energy consumption.

[0051] It should be noted that the winding directions of the steel wire rope 63 in the left front leg, the left rear leg and the right middle leg on the driving winding wheel 61 and the driven winding wheel 62 are opposite, and the winding directions of the steel wire rope 63 in the right front leg, the right rear leg and the left middle leg on the driving winding wheel 61 and the driven winding wheel 62 are the same. Specifically, as shown in FIG. 4, the winding direction of the steel wire rope 63 in the left front leg on the driving winding wheel 61 is counterclockwise, and the winding direction of the steel wire rope 63 in the left front leg on the driven winding wheel 62 is clockwise. The winding direction of the steel wire rope 63 in the left rear leg on the driving winding wheel 61 is clockwise, and the winding direction of the steel wire rope 63 in the left rear leg on the driven winding wheel 62 is counterclockwise. The winding direction of the steel wire rope 63 in the right middle leg on the driving winding wheel 61 is counterclockwise, and the winding direction of the steel wire rope 63 in the right middle leg on the driven winding wheel 62 is clockwise. The winding direction of the steel wire rope 63 in the right front leg on the driving winding wheel 61 is clockwise, and the winding direction of the steel wire rope 63 in the right front leg on the driven winding wheel 62 is counterclockwise. The winding direction of the steel wire rope 63 in the right rear leg on the driving winding wheel 61 is counterclockwise, and the winding direction of the steel wire rope 63 in the right rear leg on the driven winding wheel 62 is clockwise. The winding direction of the steel wire rope 63 in the left middle leg on the driving winding wheel 61 is clockwise, and the winding direction of the steel wire rope 63 in the left middle leg on the driven winding wheel 62 is counterclockwise. Figure 5As shown, one end of the steel wire rope 63 in the left front leg and the left rear leg is wound clockwise on the driving winding wheel 61, and the other end is wound counterclockwise on the driven winding wheel 62; one end of the steel wire rope 63 in the right middle leg is wound counterclockwise on the driving winding wheel 61, and the other end is wound clockwise on the driven winding wheel 62. Both ends of the steel wire rope 63 in the right front leg and the right rear leg are wound clockwise on the driving winding wheel 61 and the driven winding wheel 62; the steel wire rope 63 in the left middle leg is wound counterclockwise on the driving winding wheel 61 and the driven winding wheel 62. The reason for such design is that, for the leg structure on the left side, the swing of the hip joint forward is the outbound, and the swing backward is the return, and in the process of the swing of the hip joint backward, the foot end gradually moves away from the machine body, so that the steel wire rope 63 is wound in the reverse direction, so that the foot end gradually moves inward, and the movement track of the foot end is parallel to the machine body. For the leg structure on the right side, the swing of the hip joint backward is the outbound, and the swing forward is the return, and in the process of the swing of the hip joint backward, the foot end gradually moves close to the machine body, so that the steel wire rope is wound in the same direction, so that the foot end gradually moves outward, and the movement track of the foot end is parallel to the machine body.

[0052] Referring to Figure 2 , Figure 3 and Figure 4 , the foot 4 of the embodiment further comprises a sliding rod 41, and the foot 4 is slidingly connected with the lower leg 3 through the sliding rod 41. The sliding rod 41 is sleeved with a buffer spring 42. The foot 4 of the robot of the embodiment is designed to be elastic, which provides the robot with landing buffer and ensures that the six leg structures of the robot are always in contact with the ground on uneven ground.

[0053] Referring to Figure 5 , the first driving mechanism 8 of the embodiment comprises a first driving motor 81, 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 corresponds to the front leg, and the other group of the worm gear assembly and the second flexible transmission assembly corresponds to the rear leg. Each group of the worm gear assembly comprises a first worm gear 82 and a first worm 83 which are meshingly connected. Each group of the second flexible transmission assembly comprises a first sprocket 84, a second sprocket 85 and a first chain 86. The first worm 83 in the two groups of the worm gear assembly is coaxially connected to the motor shaft of the first driving motor 81. The two first worm gears 82 are rotationally installed on the machine body 7 and are coaxially connected with the corresponding first sprocket 84. The second sprocket 85 is sleeved at the first joint shaft 11 in the corresponding leg structure, and the first chain 86 is looped around the first sprocket 84 and the second sprocket 85 and is tensioned.

[0054] Referring to Figure 5The second driving mechanism 9 of the embodiment comprises a second driving motor 94 and a third flexible transmission assembly, the third flexible transmission assembly comprising a third sprocket 91, a fourth sprocket 92 and a second chain 93, the third sprocket 91 being connected to the motor shaft of the second driving motor 94, the fourth sprocket 92 being sleeved on the first joint shaft 11 in the corresponding leg structure, and the second chain 93 being wound around the third sprocket 91 and the fourth sprocket 92 and being tensioned.

[0055] When the first driving motor 81 drives the two first sprockets 84 in the same group to rotate through the corresponding two groups of worm gear assemblies, the rotation of the two second sprockets 85 is driven through the transmission of the first chain 86, and the rotation of the first joint shaft 11 connected to each second sprocket 85 is driven. Thus, the driving control of the front and rear legs is realized through one first driving motor 81. When the second driving motor 94 drives the third sprocket 91 to rotate, the fourth sprocket 92 is driven to rotate through the transmission of the second chain 93, and the first joint shaft 11 connected to the fourth sprocket 92 is driven to rotate, thereby realizing the driving control of the middle leg. The embodiment can realize the driving of the six legs through four driving motors, thereby 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 movement.

[0056] In addition, the left front leg, the left rear leg and the right middle leg of the embodiment are a group of synchronous movements, and the right front leg, the right rear leg and the left middle leg are a group of synchronous movements. When the two first driving motors 81 rotate forward and the two second driving motors 94 rotate reversely, the left front leg, the left rear leg and the right middle leg step forward, at the same time, the foot 4 of the right front leg, the right rear leg and the left middle leg contacts the ground and kicks the ground, and the robot moves forward. When the left front leg, the left rear leg and the right middle leg complete one swing phase and the right front leg, the right rear leg and the left middle leg complete one support phase, the two first driving motors 81 rotate reversely and the two second driving motors 94 rotate forward, the right front leg, the right rear leg and the left middle leg step forward, the foot 4 of the left front leg, the left rear leg and the right middle leg contacts the ground and kicks the ground, and the robot moves forward. Such a cycle is repeated to realize the movement mode of the triangular gait of the hexapod robot, thereby increasing the stability of the hexapod robot movement.

[0057] Working principle of the hexapod robot:

[0058] Taking the left front leg, the left rear leg and the right middle leg stepping forward first and the right front leg, the right rear leg and the left middle leg supporting the ground as an example for description.

[0059] Forward movement: two first driving motors 81 rotate forward, two second driving motors 94 rotate reversely, the first joint shaft 11 of the left front leg and the left rear leg rotates clockwise, the first joint shaft 11 of the right middle leg rotates counterclockwise, and the joint housings 12 on the left and right sides rotate in the same direction. Among them, the driving bevel gear 52 of the left leg rotates clockwise under the action of the fixed bevel gear 51 while rotating with the joint housing 12, the driving bevel gear 52 rotates clockwise through the one-way bearing 53 and the gear shaft 55 to drive the driving pulley 56 to rotate clockwise, the driving pulley 56 drives the driven pulley 57 to rotate clockwise through the synchronous belt 58, and the third pin shaft 27 rotates clockwise to drive the crank 23 to rotate clockwise. The crank 23 further drives the output rod 22 to rotate clockwise upward through the rocker 24 and the second joint shaft 28, thereby realizing the lifting action of the left small leg 3. Subsequently, the output rod 22 rotates counterclockwise to lower the left small leg 3. The right middle leg moves in the opposite direction, and the left front leg, the left rear leg and the right middle leg complete the stepping action. At the same time, the driving winding wheel 61 of the left front leg and the left rear leg rotates clockwise with the first joint shaft 11 to wind the steel wire rope 63, the driven winding wheel 62 releases the steel wire rope 63 by overcoming the elastic force of the torsional spring 64, and the second joint shaft 28 rotates with the driven winding wheel 62 to swing the small leg 3 laterally outward. Similarly, the right middle leg also swings laterally outward, that is, the left front leg, the left rear leg and the right middle leg swing laterally outward while stepping.

[0060] The first joint shaft 11 of the right front leg and the right rear leg also rotates clockwise, the first joint shaft 11 of the left middle leg rotates counterclockwise, and the joint housings 12 on the left and right sides rotate in the same direction. Among them, the driving bevel gear 52 of the right leg rotates clockwise under the action of the fixed bevel gear 51 while rotating with the joint housing 12, and the outer ring of the one-way bearing 53 idles with the driving bevel gear 52 due to the one-way bearing 53 only transmitting rotation to one side, without transmitting rotation to the inner ring, so the gear shaft 55 remains stationary. The thigh 2 remains unchanged, and the foot end is always in contact with the ground. The foot end of the left middle leg is also always in contact with the ground, and the body 7 moves forward under the driving of the reverse rotation of the hip joint 1, and the foot end is in a state of kicking the ground, thereby pushing the whole robot forward. At the same time, the driving winding wheel 61 of the right front leg and the right rear leg rotates clockwise with the first joint shaft 11, the driving winding wheel 61 winds the steel wire rope 63, the driven winding wheel 62 releases the steel wire rope 63 by overcoming the elastic force of the torsional spring 64, and the second joint shaft 28 rotates with the driven winding wheel 62 to swing the small leg 3 laterally outward. The foot 4 gradually moves away from the body, and the movement trajectory of the foot 4 is always parallel to the body 7, avoiding the problem of foot end slipping.

[0061] Turning process: when the rotation speed of the first driving motor 81 is less than the rotation speed of the second driving motor 94, the step length of the left front leg and the left rear leg is less than the step length of the right middle leg, and the hexapod robot turns left. Conversely, when the rotation speed of the first driving motor 81 is greater than the rotation speed of the second driving motor 94, the step length of the left front leg and the left rear leg is greater than the step length of the right middle leg, and the hexapod robot turns right. That is, the turning of the hexapod robot is realized by differential rotation.

[0062] Embodiment 2:

[0063] The embodiment provides a foot end trajectory correction method of a low-power one-way transmission hexapod robot, and the correction process comprises the following steps:

[0064] 1. Definition of coordinate system:

[0065] In order to clarify the motion mechanism of the robot described in the application, a kinematic model of a single leg system is established. As shown in Figure 6 , Figure 7 , the rotation center of the hip joint is defined as the origin of the local coordinate system , , the x-axis is along the forward direction of the robot, and the forward direction is positive, , the y-axis is along the vertical direction, and the upward direction is positive, , and the z-axis is determined according to the right-hand rule. is the hip joint swing angle, and the forward swing is positive and the backward swing is negative.

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

[0067] The motion of the robot single leg is derived from the rotation of the motor. Let the motor output speed be , after the worm gear (reduction ratio ) and chain transmission (transmission ratio ), the first joint shaft 11 of the hip joint 1 is driven to rotate. The total reduction ratio of the system is:

[0068]

[0069] The relationship between the hip joint swing angle speed and the motor speed is:

[0070]

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

[0072] The application utilizes the winding wheel and steel wire rope to realize the active following of the knee joint to the hip joint. The parameters are defined, is the radius of the active winding wheel 61 at the hip joint. Radius of the driven pulley 62 at the knee joint. Swing angle of the shank axis relative to the vertical direction of the knee joint, positive for counterclockwise rotation and negative for clockwise rotation (initial swing angle is Related to the initial installation position of the robot shank.

[0073] According to the wire drive principle, the length of the steel wire rope is conserved. When the hip joint rotation angle , the knee joint rotation angle satisfies the linear relationship , that is, the knee joint rotation angle is:

[0074]

[0075] Wherein is the geometric coupling coefficient, is the direction coefficient.

[0076] 4. Foot end motion trajectory equation and non-slip condition of support phase:

[0077] The invention adopts bevel gears matched with one-way bearings (one-way transmission mechanism 5) to drive four-bar linkage mechanisms (thigh 2), so as to realize the lifting and falling of the swing phase and the approximate straight line motion trajectory of the foot end of the support phase. The fixed bevel gear is defined as , the number of teeth of the driving bevel gear is , and the synchronous belt transmission ratio is .

[0078] The logical selection function of the one-way bearing is defined as :

[0079]

[0080] The crank input angle of the four-bar linkage mechanism is the rate of change of the hip joint swing angle:

[0081]

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

[0083]

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

[0085] A four-bar linkage vector loop model is established, is the length of the robot shank, and the distance between the first pin shaft and the third pin shaft is 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 The analytical function of the input angle

[0099]

[0100] According to the geometric relationship, the foot position of the robot in three-dimensional space can be obtained:

[0101]

[0102] wherein, is the distance from the hip joint rotation center to the third pin shaft;

[0103] Substituting (3), (6), and (12) into the above formula, the analytical formula of the foot trajectory of the hexapod robot in three-dimensional space can be obtained:

[0104]

[0105] Substituting (4) into the above formula, the corresponding foot trajectory of the swing phase can be obtained:

[0106]

[0107] Similarly, substituting (4) into (14), the foot trajectory of the support phase can be obtained:

[0108]

[0109] To realize that the robot does not slip at the foot end of the support phase, i.e., the foot trajectory is approximately a straight line, the lateral distance of the foot end must be constant, i.e., , for Regarding Taking the derivative, we can obtain:

[0110]

[0111] wherein Further organizing the above formula, we can obtain:

[0112]

[0113] Considering In the travel interval, it is not 90°, so we can obtain:

[0114] ​

[0115] Thus, the required geometric coupling coefficient of the winding wheel is achieved to support the foot end without slipping. However, since the design value cannot be changed in real time, in order to achieve the anti-slip effect of the "approximate straight line" of the foot end, the working condition at the maximum swing angle in the gait cycle is selected for parameter matching. That is, the design of the geometric coupling coefficient of the winding wheel needs to meet the following engineering approximation condition:

[0116]

[0117] wherein, is the maximum swing angle of the calf axis relative to the vertical direction of the knee joint.

[0118] At the maximum swing angle, the geometric nonlinear effect is the strongest, and the trend of lateral slip of the leg is the largest. Selecting this place can limit the lateral slip in the entire gait cycle within a very small range, thereby ensuring the straightness in the whole cycle.

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

Claims

1. A low-power unidirectional transmission hexapod robot, characterized in that, The robot comprises a body and six leg structures which are symmetrically arranged 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 sequentially connected, 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.

2. The low-power unidirectional transmission hexapod robot according to claim 1, characterized in that, 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.

3. The low-power unidirectional transmission hexapod robot according to claim 2, 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.

4. The low-power unidirectional transmission hexapod robot according to claim 2, characterized in that, The robot further comprises 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.

5. 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.

6. The low-power unidirectional transmission hexapod robot according to claim 1, wherein, The robot further comprises a first driving mechanism and a second driving mechanism, and each leg structure on each side is provided as a front leg, a middle leg and a rear leg; the first driving mechanism is provided with two and is symmetrically arranged 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 symmetrically arranged in the body, each second driving mechanism corresponding to drive the middle leg on the same side.

7. The low-power unidirectional transmission hexapod robot according to claim 6, characterized in that, The first driving mechanism comprises a first driving motor, a worm gear assembly and a second flexible transmission assembly, and 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.

8. The low-power unidirectional transmission hexapod robot according to claim 6, characterized in that, 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.

9. A method for correcting the trajectory of a leg end of a low-power unidirectional transmission hexapod robot, characterized by, The low-power-consumption unidirectional transmission six-legged robot according to claim 4, 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.

10. The foot trajectory correction method for a low-power consumption unidirectional transmission hexapod robot according to claim 9, 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.

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