Rigid-flexible series-parallel humanoid leg biped robot

Abstract

The invention relates to a rigid-flexible series-parallel humanoid leg biped robot which comprises a horizontally arranged base. The driving modules are arranged at the two ends of the base; the middle platform is correspondingly arranged below the two ends of the base; the cable-driven parallel mechanism is connected with the output end of the driving module and the middle platform; the foot ends are arranged below the corresponding middle platform; the connecting rod transmission mechanism is connected with the foot ends, the middle platform and the SR connecting rods; according to the robot, under driving of the cable-driven parallel mechanism, the foot ends have six degrees of freedom consistent with the legs, the flexibility is higher, and the requirements of complex scenes are met; an S-R-U branch chain in the robot is consistent with an actual human leg motion mode, a mixed connection mechanism can adopt a series structure kinematics solving method, and the gait planning process is greatly simplified; rope driving is adopted, the inertia is small, the load ratio and the working space are large, and the requirements for light weight and flexibility of the robot are met; the driving part and the transmission part both adopt parallel structure design, and the whole robot has the advantages of high precision and good stability.

Description

Technical Field

[0001] The present invention relates to the field of bionic biped robots, and particularly to a humanoid leg biped robot applied to flexible gait walking. Background Art

[0002] Robotics takes the integration of mechatronics and intelligent algorithms as the core, driving the innovation of industrial automation, intelligent logistics, high-risk environment operations and human-machine collaboration scenarios. In the field of bionic robots, legged robots imitate the walking methods of organisms, and a single leg has more degrees of freedom, showing good terrain adaptability in harsh environments. Traditional biped robots mostly have a series structure and adopt a motor drive strategy. Robots with this series structure rely too much on the performance of motors and reducers, and have problems such as insufficient stiffness, cumulative errors and poor stability when encountering complex terrains or bearing a certain load. Although a few parallel solutions can improve the accuracy and stiffness of the robot to a certain extent, the rigid connection method restricts the flexibility and working space of the robot.

[0003] In summary, how to reduce the self-inertia of the robot, improve the payload ratio while enhancing the accuracy and flexibility to meet the stable walking on complex terrains has become an urgent problem to be solved by researchers in this field. Summary of the Invention

[0004] The technical problem to be solved by the present invention is: how to reduce the self-inertia of the robot, improve the payload ratio while enhancing the accuracy and flexibility to meet the stable walking on complex terrains has become an urgent problem to be solved by researchers in this field.

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

[0006] The present invention is a rigid-flexible hybrid humanoid leg biped robot, including: a horizontally arranged base;

[0007] A drive module, which is arranged at both ends of the base; a middle platform, which is correspondingly arranged below both ends of the base; a cable-driven parallel mechanism, which connects the output ends of the drive module and the middle platform, and is adapted to drive the middle platform to perform six-degree-of-freedom motion; a foot end, which is arranged below the corresponding middle platform; a link transmission mechanism, which connects the foot end and the middle platform; an SR link, the top end of which is connected to the bottom of the middle platform through a spherical pair, and the bottom end of which is connected to one of the RR links in the link transmission mechanism through a rotating pair.

[0008] Further, the drive module includes: a mounting seat, which is fixed on the upper surface of the base; N pairs of wire winding drum groups, which are rotatably connected to the mounting seat and are controlled by corresponding motors to rotate, and are circumferentially arranged at equal intervals on the upper surface of the base, and each pair of wire winding drum groups includes two wire winding drums, where N is an integer greater than 3.

[0009] Further, the driving module includes: a mounting base fixed on the upper surface of the base; N pairs of winding drum groups rotatably connected to the mounting base and controlled by corresponding motors to rotate, circumferentially arranged at equal intervals on the upper surface of the base, and each pair of the winding drum groups includes two winding drums, where N is an integer greater than 3.

[0010] Further, the anchor point group and the winding drum group are arranged with a 360° / N circumferential dislocation up and down.

[0011] Further, an upper pulley is arranged on the upper surface of the base, and a lower pulley is arranged on the lower surface of the base. When the rope passes through the base, it is guided by the upper pulley and the lower pulley.

[0012] Further, the link transmission assembly includes: three RR links constituting a 3-UU parallel mechanism, one end of the top of which is connected to the lower surface of the intermediate platform through a universal joint, and one end of the bottom of which is connected to the upper surface of the foot end through a universal joint; the top of the SR link is connected to the lower surface of the base through a spherical joint, and the bottom of the SR link is connected to one side close to the top of one of the RR links through a revolute joint.

[0013] Further, when simulating hip joint movement, the SR link, the RR link, and the foot end remain relatively stationary, and the driving module drives the intermediate platform to complete the movement around the center of the bottom of the base 1 through the cable-driven parallel mechanism, and the lower link transmission mechanism and the SR link always remain relatively stationary.

[0014] Further, when simulating knee joint movement, the driving module drives the intermediate platform to complete the movement around the spherical joint between the top of the SR link and the base through the cable-driven parallel mechanism, and the lower link transmission mechanism and the SR link always remain relatively stationary.

[0015] Further, when simulating ankle joint movement, the driving module drives the intermediate platform to perform pitching and yawing movements through the cable-driven parallel mechanism, and the foot end is connected to the intermediate platform through the link transmission mechanism to realize the movement of the foot end.

[0016] Advantages of the present invention:

[0017] (1) Driven by the cable-driven parallel mechanism, the foot end of the robot has 6 degrees of freedom consistent with the leg, with higher flexibility to meet the requirements of complex scenarios.

[0018] (2) In this robot, the SR link and the RR link form an S-R-U equivalent branch chain, and the movement mode of this S-R-U branch chain is consistent with that of the actual human leg. The hybrid mechanism can adopt the solution method of serial structure kinematics, greatly simplifying the gait planning process.

[0019] (3) The invention adopts cable drive, has a small self-inertia, and a large load ratio and working space, meeting the requirements of robot lightweight and flexibility.

[0020] (4) For the robot drive, the transmission part adopts a parallel structure design, and the overall robot has the advantages of high precision and good stability. Description of the Drawings

[0021] The present invention will be further described below in conjunction with the drawings and embodiments.

[0022] Figure 1 It is a schematic structural diagram of this embodiment.

[0023] Figure 2 It is a schematic structural diagram of the drive module.

[0024] Figure 3 It is a schematic structural diagram of the cable-driven parallel mechanism.

[0025] Figure 4 It is a schematic structural diagram of the link transmission mechanism.

[0026] Figure 5 It is a schematic structural diagram of the equivalent branch chain composed of the RR link and the SR link.

[0027] Figure 6 It is a schematic diagram of hip joint movement.

[0028] Figure 7 It is a schematic diagram of knee joint movement.

[0029] Figure 8 It is a schematic diagram of ankle joint movement.

[0030] In the figure: 1. Base, 2. SR link, 3. Intermediate platform, 4. Foot end, 5. Drive module, 6. Cable-driven parallel mechanism, 7. Link transmission mechanism, 8. Motor, 9. Mounting seat, 10. Winding drum, 01. Cable, 02. Anchor point, 12. Upper pulley, 13. Lower pulley, 14. Ball joint, 15. Telescopic member, 16. Universal joint, 17. Rotating joint, 21. RR link. Detailed Embodiment

[0031] The present invention will now be further described in detail in conjunction with the drawings. These drawings are all simplified schematic diagrams, only illustrating the basic structure of the present invention in a schematic manner, so they only show the components related to the present invention.

[0032] In this embodiment, a 6-degree-of-freedom rigid-flexible hybrid biped robot with a human leg joint motion form is proposed by combining the characteristics of a cable-driven parallel mechanism and a hybrid structure; this robot has a small self-inertia, a large load ratio, high stiffness, precision, and flexibility, and can walk efficiently and stably on complex terrains, as follows:

[0033] See Figure 1 , this embodiment is a rigid-flexible hybrid biped robot. The robot in the figure is in a standing state. From top to bottom in the figure, there are a base 1, two intermediate platforms 3, and two foot ends 4. The ball joint at the upper end of the SR link 2 is equivalent to the human hip joint, the rotating joint where the SR link 2 is connected to one of the lower RR links 21 is equivalent to the knee joint, and the universal joint below the RR link 21 connected to the SR link 2 is equivalent to the ankle joint; the cable-driven parallel mechanism 6 constitutes the thigh, and the link transmission mechanism 7 constitutes the calf; the kinematic pairs are equivalent to the joints.

[0034] Among them, a driving module 5 is provided on the top of the base 1, a cable-driven parallel mechanism 6 is provided between the intermediate platform 3 and the base 1, a link transmission mechanism 7 is provided between the intermediate platform 3 and the foot end 4, and an SR link 2 is transmitted between the base 1 and the link transmission mechanism 7.

[0035] See Figure 2 , Figure 2 is a schematic structural diagram of the driving module on the upper surface of the base. The driving module includes a mounting seat 9 fixed at the center of the upper surface of the base 1. The horizontal cross-section of the mounting seat 9 is an equilateral triangle structure. Two wire-winding cylinders 10 are rotatably arranged outside each side of the mounting seat 9, for a total of 3 pairs of wire-winding cylinder groups, that is, 6 wire-winding cylinders 10; the motor 8 drives the corresponding wire-winding cylinder 10 to rotate by itself through a coupling.

[0036] On the outside of each wire-winding cylinder 10 and on the upper surface of the base 1, an upper pulley 12 is provided, and a lower pulley 13 is provided on the lower surface of the base 1. The upper pulley 12 and the lower pulley 13 are arranged vertically corresponding to each other. The axial directions between adjacent upper pulleys 12 are arranged in parallel, and the included angle of the axes of the lower pulleys 12 changes with the position of the intermediate platform 3, with an initial included angle of 120°; one end of the rope 01 is wound around the wire-winding cylinder 10, and the other end passes through the upper pulley 12 and the lower pulley 13 in sequence and is connected to the cable-driven parallel mechanism 6. There are 6 ropes 01 in total.

[0037] See Figure 3 , Figure 3It is a schematic structural diagram of the cable-driven parallel mechanism 6 between the base 1 and the intermediate platform 3. The telescopic member 15 is preferably an electric cylinder. One end of the top of the telescopic member 15 is connected to the center of the lower surface of the base 1 through a spherical pair 14, and one end of the bottom of the telescopic member 15 is connected to the center of the upper surface of the intermediate platform 3 through a universal pair 16. Three anchor points 02 are circumferentially and equidistantly arranged on the upper surface of the intermediate platform 3. The anchor points 02 and the wire winding drum group are arranged with a 60° circumferential offset up and down. That is, if the base 1 is rotated circumferentially by 60°, the anchor points 02 and the wire winding drum group are in a vertically corresponding relationship. The universal pair 16 is composed of rotating pairs arranged perpendicular to each other.

[0038] After the rope 01 is guided by the lower pulley 13, one end of its bottom is connected to the anchor point 02. One anchor point 02 is connected to the bottoms of two ropes 01, corresponding to the two ropes 01 of different wire winding drum groups; that is, the first wire winding drum group and the second wire winding drum group arranged adjacent to each other. The right rope 01 of the first wire winding drum group and the left rope 01 of the second wire winding drum group are connected to the same anchor point 02.

[0039] See Figure 4 , Figure 4 It is a schematic structural diagram of the link transmission mechanism 7 between the intermediate platform 3 and the foot end 4. Three RR links with special-shaped structures form a 3-UU parallel mechanism to connect the intermediate platform 3 and the foot end 4. The top of the RR link 21 is connected to the lower surface of the intermediate platform 3 through a universal pair 16, and the bottom of the RR link 21 is connected to the lower surface of the foot end 4 through a universal pair 16. The 3-UU parallel mechanism belongs to the prior art. The principle of the 3-UU parallel mechanism is: within a certain allowable error range, using an anti-parallelogram mechanism to realize that the pure rolling of an elliptical path is equivalent to the pure rolling of a circular path.

[0040] See Figure 4 , where the bottom of one RR link 21 is connected to the heel of the foot end 4 (i.e., corresponding to the right side of the foot end), and the top is connected to the right side of the lower surface of the intermediate platform 4 (i.e., above the relative side of the heel of the foot end 4 and located on the lower surface of the intermediate platform 4).

[0041] See Figure 5 , which is a schematic structural diagram of the SR link 2 connecting the base 1 and the link transmission mechanism 7. In the figure, one end of the top of the SR link 2 is connected to the right side of the lower surface of the base 1 through a spherical pair 14 (i.e., above the relative side of the heel of the foot end 4 and located on the lower surface of the base 1), and one end of the bottom of the SR 21 is connected to Figure 4 the top right side of the RR link 21 in

[0042] Specifically, the cable-driven parallel mechanism 6 provides power for the robot. The 2-DOF spatial anti-parallel quadrilateral mechanism (link transmission mechanism 7) serves as the transmission part, and the SR link 2 provides additional constraints. The spherical pair at the upper end of the SR link 2 has 14 degrees of freedom, which is the same as that of the hip joint. The motion form of the SR link 2 is consistent with that of the thigh. The revolute pair connecting the SR link 2 and the RR link 21 has 17 degrees of freedom, which is the same as that of the knee joint. The constrained motion form of the RR link 21 is consistent with that of the calf. The universal joint connecting the RR link 21 and the lower foot end 4 has 16 degrees of freedom, which is the same as the degree of freedom of the human ankle joint. The motion form of the foot end 4 is consistent with that of the actual foot. During the implementation process, since the S-R-U equivalent chain formed by the SR link 2 and the lower universal joint 16 has the same degree of freedom as the hip-knee-ankle joints of the human leg, the overall motion form of the robot is the same as the actual human walking mode.

[0043] The base 1 is fixed, and the middle platform 3 can move and rotate in all directions. The link transmission mechanism 7 has two rotational degrees of freedom. When the RR link 21 connected to the SR link 2 is fixed, the pitch and yaw motions of the middle platform 3 are equivalent to the pitch and yaw motions of the ankle joint.

[0044] The correspondence between the robot posture-drive (inverse kinematics) is as follows: The S-R-U equivalent chain has the same degree of freedom as the human leg joints. When the leg is in a determined posture, the positions of the foot end 4, the SR link 2 (thigh), and the RR link 21 (calf) in the robot are all determined. Further, the position of the link transmission mechanism 7 and the middle platform 3 is determined (the position of the foot end 4 and one of the chains is determined), and the corresponding drive is unique.

[0045] The correspondence between the robot drive-posture (forward kinematics) is as follows: During the drive process of the cable-driven parallel mechanism 6, the three working forms of the biped robot respectively correspond to the movements of the three leg joints: If the SR link 2 and the link transmission mechanism 7 in the lower space remain relatively stationary, the robot simulates the hip joint movement of the leg; if the SR link 2 remains stationary and the overall posture of the lower link transmission mechanism 7 changes but remains relatively stationary inside, the robot simulates the knee joint movement of the leg; if the SR link 2 and the RR link 21 connected below remain stationary, the robot simulates the ankle joint movement of the leg.

[0046] In this embodiment, the working process of the robot is as follows:

[0047] For a specific leg posture, the angles of each kinematic pair can be solved through kinematics, and further the displacement of each drive can be solved. The drive displacements of the cable-driven parallel mechanism and the robot posture correspond to each other. These parameters are converted into control signals through the single-chip microcomputer control system and transmitted to the drive module 5 and the electric cylinder. The drive module 5 drives the cable drum 10 to wind and unwind the cable 01, and cooperates with the electric cylinder to drive the intermediate platform 3. The intermediate platform 3 further drives the SR link 2 and the RR link 21 to reach a specific posture. During the driving process, the three working forms of the biped robot respectively correspond to the movements of the three leg joints:

[0048] (1) The robot simulates the hip joint movement, and other joints remain stationary: As Figure 6 shown, the connection between the top of the SR link 2 and the spherical pair 14 of the base 1 is consistent with the movement form of the hip joint, and can complete movements such as pitch, roll, and yaw. The SR link 2, the RR link 21, and the foot end 4 remain relatively stationary, that is, the angle between the SR link 2 and the RR link 21 does not change during the process from the standing state ( Figure 1 ) to the hip joint movement state ( Figure 6 ); when the equivalent hip joint moves, other leg joints remain relatively stationary. Correspondingly, the single-chip microcomputer control system converts the pose signal of the S pair movement in the S-R-U equivalent branch chain during the robot movement process, with the R and U kinematic pairs stationary, into a drive signal. The drive module 5 drives the intermediate platform 3 to complete the movement around the connection between the top of the SR link 2 and the spherical pair 14 of the base 1 through the cable-driven parallel mechanism 6. The lower link transmission mechanism 7 and the SR link 2 always remain relatively stationary to simulate hip joint flexion.

[0049] (2) The robot simulates the knee joint movement, and other joints remain stationary: As Figure 7 shown, the rotating pair 17 connecting the SR link 2 and the RR link 21 is consistent with the movement form of the knee joint and can complete the pitch movement. The connection between the top of the SR link 2 and the spherical pair 14 of the base 1 and the SR link 2 remain stationary, that is, the position of the SR link 2 in Figure 1 is the same as the position of the SR link 2 in Figure 7 , Figure 1 , 7The relative position between the mid-foot end 4 and the RR link 21 remains unchanged, and the equivalent hip joint and thigh remain stationary; the lower RR link 21 and the foot end 4 remain relatively stationary, and the lower leg and the foot end remain relatively stationary when the equivalent knee joint moves. Correspondingly, the single-chip microcomputer control system converts the pose signals of the R pair movement in the S-R-U equivalent branch chain during the movement of the robot, with the S and U kinematic pairs stationary, into drive signals. The drive module 5 drives the intermediate platform 3 through the cable-driven parallel mechanism 6 to complete the rotation around the revolute joint 17 at the connection between the SR link 2 and the RR link 2. The intermediate platform 4 switches to a state with the left side higher and the right side lower. One of the link transmission mechanisms 7 rotates counterclockwise around the revolute joint 17, and the lower RR link 21 and the foot end 4 always remain relatively stationary to simulate knee flexion.

[0050] (3) The robot simulates ankle joint movement while other joints remain stationary: As Figure 8 shown, the universal joints 16 at both ends of the RR link 21 have the same movement form as the ankle joint and can complete pitching and rolling motions. The ball joint 14 connection between the top of the SR link 2 and the base 1, the SR link 2, and the RR link 21 remain stationary, and the equivalent thigh and lower leg remain stationary. Correspondingly, the single-chip microcomputer control system converts the pose signals of the U pair movement in the S-R-U equivalent branch chain during the movement of the robot, with the S and R kinematic pairs stationary, into drive signals. The drive module 5 drives the intermediate platform 3 through the cable-driven parallel mechanism 6 to complete the pitching and yawing motions of the intermediate platform 3, which are equivalent to the ankle joint movement. The cable-driven parallel mechanism 6 drives the intermediate platform 3 to be adjusted to a state with the right side higher and the left side lower. The intermediate platform 3 rotates counterclockwise around the universal joint 16 at one end of the RR link connected to the SR link 2 to simulate ankle dorsiflexion. During the movement, the remaining two RR links 21 not connected to the SR link 2 follow the movement of the intermediate platform 3.

[0051] Inspired by the above ideal embodiments of the present invention, through the above description, relevant staff can completely make various changes and modifications without departing from the technical idea of this invention. The technical scope of this invention is not limited to the content in the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A rigid-flexible hybrid anthropomorphic leg biped robot, characterized in that Comprising: A horizontally arranged base; Drive modules, which are arranged at both ends of the base; An intermediate platform, which is correspondingly arranged below both ends of the base; A cable-driven parallel mechanism, which connects the output ends of the drive modules and the intermediate platform, and is adapted to drive the intermediate platform to perform six-degree-of-freedom motion; A foot end, which is arranged below the corresponding intermediate platform; A link transmission mechanism, which connects the foot end and the intermediate platform; An SR link, the top end of which is connected to the bottom of the intermediate platform through a spherical pair, and the bottom end of which is connected to one of the RR links in the link transmission mechanism through a revolute pair.

2. The biped robot with a rigid-flexible hybrid anthropomorphic leg according to claim 1, characterized in that, The drive module includes: A mounting seat, which is fixed on the upper surface of the base; N pairs of winding drum groups, which are rotatably connected to the mounting seat and are controlled by corresponding motors to rotate, and are circumferentially arranged at equal intervals on the upper surface of the base. Each pair of the winding drum groups includes two winding drums, where N is an integer greater than 3.

3. The biped robot with a rigid-flexible hybrid anthropomorphic leg according to claim 2, characterized in that, The cable-driven parallel mechanism includes: An extensible member, the top end of which is connected to the center of the lower surface of the base through a spherical pair, and the bottom end of which is connected to the center of the upper surface of the intermediate platform through a universal pair; N anchor points, which are circumferentially arranged at equal intervals on the upper surface of the intermediate platform; 2N ropes, one end of which is wound around the corresponding winding drum, and the other end of which is connected to the corresponding anchor point; among them, the two adjacent winding drums between two adjacent winding drum groups are connected to the same anchor point.

4. The flexible and rigid hybrid anthropomorphic leg biped robot according to claim 3, characterized in that, The anchor points and the winding drum groups are arranged with a 360° / N circumferential dislocation in the vertical direction.

5. A rigid-flexible hybrid anthropomorphic leg biped robot according to claim 3, characterized in that, Upper pulleys are arranged on the upper surface of the base, and lower pulleys are arranged on the lower surface of the base. When the ropes pass through the base, they are guided by the upper pulleys and the lower pulleys.

6. The dual-foot robot with a rigid-flexible hybrid anthropomorphic leg according to claim 1, characterized in that, The link transmission assembly includes: Three RR links constituting a 3-UU parallel mechanism, the top ends of which are connected to the lower surface of the intermediate platform through universal pairs, and the bottom ends of which are connected to the upper surface of the foot end through universal pairs; The bottom surface of the base is connected to the top of the SR link through a spherical pair, and the bottom of the SR link is connected to one side close to the top of one of the RR links through a revolute pair.

7. A rigid-flexible hybrid anthropomorphic leg biped robot according to claim 1, characterized in that, When simulating hip joint movement, the SR link, the RR link, and the foot end remain relatively stationary, and the drive module drives the intermediate platform to complete the movement around the center of the bottom of the base 1 through the cable-driven parallel mechanism, and the lower link transmission mechanism and the SR link always remain relatively stationary.

8. A rigid-flexible hybrid anthropomorphic leg biped robot according to claim 1, characterized in that, When simulating knee joint movement, the drive module drives the intermediate platform to complete the movement around the spherical pair between the top of the SR link and the base through the cable-driven parallel mechanism, and the lower link transmission mechanism and the SR link always remain relatively stationary.

9. The biped robot with a rigid-flexible hybrid anthropomorphic leg according to claim 1, characterized in that, When simulating ankle joint movement, the drive module drives the intermediate platform to perform pitching and yawing movements through the cable-driven parallel mechanism, and the foot end is connected to the intermediate platform through the link transmission mechanism to realize the movement of the foot end.

Images