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CN-122020978-A - Design method for parallel ankle joints of biped robot and biped robot

CN122020978ACN 122020978 ACN122020978 ACN 122020978ACN-122020978-A

Abstract

The application relates to the technical field of robots, and discloses a biped robot parallel ankle joint design method and a biped robot. According to the parallel ankle joint design method of the biped robot, two sets of space four-bar mechanisms are constructed through the ankle joint mechanical structure and all hinge point positions of all parts which are connected in parallel in the biped robot, the space four-bar mechanisms are converted into equivalent plane motion mechanisms, qualitative motion analysis is conducted on the equivalent plane motion mechanisms, then a motion model is constructed according to the motion analysis result, and the motion analysis is conducted, so that known parameter information, unknown parameter information and limiting condition information are determined, finally the known parameter information and the limiting condition information are input into the motion model to conduct kinematic equation solving, and the unknown parameter information is determined, so that the design is completed. Therefore, the design method provided by the application does not need repeated iteration for a plurality of times, has low difficulty and high efficiency, reduces the development cost, and simultaneously solves the problem of insufficient scheme optimization existing in the conventional empirical trial-and-error design method.

Inventors

  • SHE LINGJUAN
  • ZHOU SIQI
  • FU LING
  • ZENG GUANG
  • ZHOU XUDONG
  • MA DEFU

Assignees

  • 中科云谷科技有限公司

Dates

Publication Date
20260512
Application Date
20251230

Claims (10)

  1. 1. The design method of the parallel ankle joint of the biped robot is characterized by comprising the following steps of: constructing two sets of space four-bar mechanisms according to all hinge point positions of ankle joint mechanical structures connected in parallel and all parts in the biped robot; converting the space four-bar mechanism into an equivalent plane motion mechanism and carrying out qualitative motion analysis on the plane motion mechanism; Constructing a motion model according to a motion analysis result and performing a kinematic analysis to determine known parameter information, unknown parameter information and constraint condition information; inputting the known parameter information and the limiting condition information into the motion model for solving a kinematic equation so as to determine the unknown parameter information.
  2. 2. The method for designing parallel ankle joints of bipedal robots according to claim 1, wherein the constructing two sets of spatial four-bar linkages according to the mechanical structure of the ankle joints of the bipedal robots in parallel and all hinge point positions of each component comprises: determining the mechanical structure of the ankle joint in parallel connection and the positions of all hinge points; And constructing two sets of space four-bar mechanisms based on ankle crank-connecting rod-sole-shank in the ankle mechanical structure in parallel connection according to the positions of the hinge points and the connection and mutual motion relations of all parts in the ankle mechanical structure in parallel connection.
  3. 3. The parallel ankle joint design method of the bipedal robot according to claim 1, wherein the parallel ankle joint mechanical structure comprises a shank body (100), a first ankle joint motor (200), a second ankle joint motor (300), a sole (400), a second double-headed connecting rod (700) and a first double-headed connecting rod (600), wherein a cross shaft mounting seat (410) and a connecting rod mounting seat (420) are arranged on the sole (400), the shank body (100) is connected with the cross shaft mounting seat (410) through a cross shaft (500) to form a universal joint, the first ankle joint motor (200) and the second ankle joint motor (300) are arranged on the shank body (100) and are respectively provided with a first motor crank (210) and a second motor crank (310) at output ends, and two ends of the first double-headed connecting rod (600) are respectively hinged with the first motor crank (210) and the connecting rod mounting seat (420) and two ends of the second double-headed connecting rod (700) are respectively hinged with the second motor crank (210) and the connecting rod mounting seat (420); the motion analysis for converting the space four-bar mechanism into an equivalent planar motion mechanism and qualitatively analyzing the planar motion mechanism comprises the following steps: Taking the rotation center of the cross shaft (500) as a coordinate origin O, and establishing a space coordinate system, wherein the upward direction of the normal line of the sole (400) when being parallel to the horizontal plane is taken as the positive direction of the Z axis, and the extending direction of the sole (400) when being parallel to the horizontal plane is taken as the X axis; projecting the space four-bar linkage mechanism to an X-O-Z plane of the space coordinate system so as to convert the space four-bar linkage mechanism into an equivalent plane motion mechanism, wherein swinging of the first motor crank (210) or the second motor crank (310) can be equivalent to up-and-down sliding of an upper sliding block (211) in the plane motion mechanism, and rolling of the connecting rod mounting seat (420) is equivalent to up-and-down sliding of a lower sliding block (421) in the plane motion mechanism; The motion analysis is carried out, wherein in an initial state, the lower leg body (100) is vertical to the ground, when the ankle joint is single in pitching, the lower leg body (100) and the upper sliding block (211) rotate around an O point, meanwhile, the upper sliding block (211) slides up and down, and when the ankle joint is single in rolling, the lower sliding block (421) slides up and down, and the upper sliding block (211) is driven to slide synchronously through a corresponding connecting rod.
  4. 4. The method for designing the parallel ankle joint of the bipedal robot according to claim 3, wherein a first set of the spatial four-bar mechanisms is composed of a first motor crank (210) -a first double-head connecting rod (600) -a sole (400) -a shank body (100), a second set of the spatial four-bar mechanisms is composed of a second motor crank (310) -a second double-head connecting rod (700) -a sole (400) -a shank body (100), and the motion analysis processes of the two sets of the spatial four-bar mechanisms are identical, and the first set of the spatial four-bar mechanisms is taken as an example for the kinematic analysis; Taking the vertical height h1 of the installation position of the first ankle joint motor (200) from the rotation center of the cross shaft (500) and the range (0, theta max ) of the up/down swing angle theta of the first motor crank (210) as the known parameter information; Taking a movement range (phi min ,φ max ) of a pitch angle phi of the ankle joint and a movement range (phi min ,ψ max ) of a roll angle phi of the ankle joint as the limiting condition information; and taking the length r1 of the first motor crank (210), the difference value a of the upper hinge point and the lower hinge point of the first double-head connecting rod (600) on the X axis, the width 2b between the lower hinge points of the first double-head connecting rod (600) and the second double-head connecting rod (700) and the length l 1 of the first double-head connecting rod (600) as the unknown parameter information.
  5. 5. The method for designing a parallel ankle joint of bipedal robot according to claim 4, wherein the constructing a motion model based on the motion analysis result and performing a kinematic analysis to determine the known parameter information, the unknown parameter information and the constraint condition information comprises: Constructing a motion equation, and sequentially determining the length of the first motor crank (210), the front and back positions of the connecting rod mounting seat (420), the width of the connecting rod mounting seat (420) and the length of the first double-head connecting rod (600) according to the known parameter information and the limiting condition information; The length of the first motor crank (210) is r, the front and rear positions of the connecting rod mounting seat (420) are the difference value a of the upper hinge point and the lower hinge point of the first double-head connecting rod (600) on the X axis, the width of the connecting rod mounting seat (420) is half of the width b between the lower hinge points of the first double-head connecting rod (600) and the second double-head connecting rod (700), and the length of the first double-head connecting rod (600) is l 1 .
  6. 6. The bipedal robot parallel ankle joint design method of claim 5, wherein determining the length of the first motor crank (210) includes: The up-down sliding range of the upper slider (211) is determined according to the following formula (1) : (1); When roll is not considered and the pitch angle of the ankle joint reaches the maximum, it should be ensured that the upper slider (211) does not exceed its maximum range of motion, by combining the above formula (1) and the following formula (2), it is thereby obtained: (2); (3); And determining the lower limit r min of the length of the first motor crank (210) according to the formula (3), and taking r min + (1-2) mm as the length design value r of the first motor crank (210).
  7. 7. The bipedal robot parallel ankle joint design method of claim 5, wherein determining the front-rear position of the link mount (420) includes: during ankle joint motion, the upper bearing angle ω 1 should satisfy the triangle sine theorem: <ω max (4); (5); Wherein, the For the length of the first double-headed link (600), will Properly shrinking and taking H 1 , taking Φ=Φ max : (6); According to the formula (6), the range of a can be determined, and then a proper value of a is selected as the design value of the front and rear positions of the connecting rod mounting seat (420) according to the actual design requirement of the structure.
  8. 8. The bipedal robot parallel ankle joint design method of claim 5, wherein determining the width of the link mount (420) comprises: during ankle motion, the lower bearing angle ω 2 should satisfy: <max(ω 2 )(7) Taking the limit value ψ=ψ max , θ=0°, where l 1= h 1 is available: (8) In addition, the movable range of the lower slider (421) : (9) Considering that the sliding of the lower sliding block (421) inevitably drives the upper sliding block (211) to follow the sliding, the moving range of the upper sliding block (211) is limited by the length of the first motor crank (210) and cannot be infinitely increased, the b value is ensured to be reduced when the design is carried out And determining the minimum value b min of the width of the connecting rod mounting seat (420) according to the formula (8), and taking the value b min + (1-2) mm as the design value b of the width of the connecting rod mounting seat (420).
  9. 9. The bipedal robot parallel ankle joint design method of claim 8, wherein determining the length of the first bipedal link (600) includes: Assuming that the ankle joint does not roll when the first motor crank (210) strikes a horizontal position (i.e., θ=0°), the ankle joint pitch angle is at a middle position of the pitch angle design value, namely: (10); the length of the first double-head connecting rod (600) is as follows: (11); And combining the previously determined r, a and b values, and calculating the length l 1 of the first double-head connecting rod (600).
  10. 10. A biped robot comprising parallel ankle joints designed by the biped robot parallel ankle joint design method according to any one of claims 1 to 9.

Description

Design method for parallel ankle joints of biped robot and biped robot Technical Field The application belongs to the technical field of robots, and particularly relates to a biped robot parallel ankle joint design method and a biped robot. Background With the development of science and technology, robots are more and more favored by people. The ankle joint performance of a biped humanoid robot directly affects the flexibility and stability of the motion. At present, a parallel ankle joint mechanism is generally adopted in the field, a lower leg and a sole are connected through a cross shaft, a joint motor is arranged on the lower leg, rotary motion is output through a crank, and the sole is driven through two connecting rods, so that pitching and rolling degrees of freedom are realized. Crank armConnecting rodSole of footThe calf constitutes two sets of space four-bar mechanisms with spherical hinges, and the design of the size parameters of the space four-bar mechanisms directly influences the flexibility of joints and the equivalent moment of motors, and is a key in the design of ankle joints. At present, conventional designs are mainly based on empirical trial and error, structural engineers set initial dimensions according to experience, and then gradually approach design indexes through repeated manual correction and iterative verification. Although the method can finally achieve the design target, the whole process is low in efficiency, long in period, and the design quality is limited to personal experience to a great extent, and the systematic and theoretical parameter matching guidance is lacked, so that the development cost is high and the scheme optimization is insufficient. Disclosure of Invention The application aims to provide a biped robot parallel ankle joint design method and a biped robot, which are used for solving the problems of low efficiency, long period, high development cost and insufficient scheme optimization of the existing design method based on empirical trial-and-error. In order to achieve the above object, a first aspect of the present application provides a parallel ankle joint design method of a bipedal robot, comprising: constructing two sets of space four-bar mechanisms according to all hinge point positions of ankle joint mechanical structures connected in parallel and all parts in the biped robot; converting the space four-bar mechanism into an equivalent plane motion mechanism and carrying out qualitative motion analysis on the plane motion mechanism; Constructing a motion model according to a motion analysis result and performing a kinematic analysis to determine known parameter information, unknown parameter information and constraint condition information; inputting the known parameter information and the limiting condition information into the motion model for solving a kinematic equation so as to determine the unknown parameter information. In some embodiments, the constructing two sets of space four-bar mechanisms according to the ankle joint mechanical structure of the biped robot and all hinge point positions of each component comprises: determining the mechanical structure of the ankle joint in parallel connection and the positions of all hinge points; And constructing two sets of space four-bar mechanisms based on ankle crank-connecting rod-sole-shank in the ankle mechanical structure in parallel connection according to the positions of the hinge points and the connection and mutual motion relations of all parts in the ankle mechanical structure in parallel connection. In some embodiments, the ankle joint mechanical structure comprises a shank body, a first ankle joint motor, a second ankle joint motor, a sole, a second double-headed connecting rod and a first double-headed connecting rod, wherein a cross shaft installation seat and a connecting rod installation seat are arranged on the sole, the shank body is connected with the cross shaft installation seat through a cross shaft to form a universal joint, the first ankle joint motor and the second ankle joint motor are both arranged on the shank body, a first motor crank and a second motor crank are respectively arranged at output ends of the first ankle joint motor, two ends of the first double-headed connecting rod are respectively hinged with the first motor crank and the connecting rod installation seat, and two ends of the second double-headed connecting rod are respectively hinged with the second motor crank and the connecting rod installation seat; the motion analysis for converting the space four-bar mechanism into an equivalent planar motion mechanism and qualitatively analyzing the planar motion mechanism comprises the following steps: Taking the rotation center of the cross shaft as a coordinate origin O, and establishing a space coordinate system, wherein the upward direction of the normal line when the sole is parallel to the horizontal plane is taken as the positive direction of the Z axis, an