Lightweight 4-degree-of-freedom leg mechanism of bionic quadruped robot

{
  "publication_number": "US11142268B2",
  "country": "US",
  "kind": "B2",
  "title": "Lightweight 4-degree-of-freedom leg mechanism of bionic quadruped robot",
  "abstract": "A lightweight 4-degree-of-freedom leg mechanism of a bionic quadruped robot, which includes a hip-joint lateral-swing assembly, a thigh longitudinal-swing assembly and a shank longitudinal-swing assembly. The hip-joint lateral-swing assembly includes a hip-joint swing cylinder and an electro-hydraulic actuator. One end of the electro-hydraulic actuator and one end of the thigh longitudinal-swing assembly are respectively connected to the hip-joint swing cylinder via a connecting block. The other end of the electro-hydraulic actuator is hinged to a side of the thigh longitudinal-swing assembly. The other end of the thigh longitudinal-swing assembly is hinged to the shank longitudinal-swing assembly.",
  "claims": [
    "1. A 4-degree-of-freedom leg mechanism of a bionic quadruped robot, comprising: a hip-joint lateral-swing assembly; a thigh longitudinal-swing assembly; and a shank longitudinal-swing assembly; wherein the hip joint lateral-swing assembly comprises a hip-joint swing cylinder and an electro-hydraulic actuator; one end of the electro-hydraulic actuator and one end of the thigh longitudinal-swing assembly are respectively connected to the hip joint swing cylinder via a connecting block; the other end of the electro-hydraulic actuator is hinged to a side of the thigh longitudinal-swing assembly; the other end of the thigh longitudinal-swing assembly is hinged to the shank longitudinal-swing assembly; and an oil line in the electro-hydraulic actuator and an oil line in the thigh longitudinal-swing assembly are respectively communicated with an oil line in a lateral-swing shaft of the hip joint swing cylinder through a passage in the connecting block; a lower end of the connecting block is provided with an oil inlet and an oil outlet; an oil distribution shaft is rotatably arranged at both ends of the lower end of the connecting block, respectively; an oil line communicating with the oil inlet and at least one oil hole communicating with the oil outlet are respectively arranged in the oil distribution shaft.",
    "2. The 4-degree-of-freedom leg mechanism of claim 1, wherein an upper end of the connecting block is fixedly connected to a flange of the lateral-swing shaft via a bolt; the lower end of the connecting block is of a U-shaped structure; both sides of each of the at least one oil hole are respectively provided with a rigid seal; and the rigid seal is sealedly connected to the electro-hydraulic actuator and the thigh longitudinal-swing assembly, respectively.",
    "3. The 4-degree-of-freedom leg mechanism of claim 2, wherein the electro-hydraulic actuator comprises a cylinder body, a cylinder rod and a guide rod; the cylinder rod and the guide rod are arranged in the cylinder body; a top end of the cylinder rod and a top end of the guide rod are connected through a connecting plate; the top end of the cylinder rod is connected to an lug ring; an end of the cylinder body is provided with an axle steel housing; the lug ring is hinged to a side wall of the thigh longitudinal-swing assembly; and the axle steel housing is fixedly connected to the oil distribution shaft.",
    "4. The 4-degree-of-freedom leg mechanism of claim 3, wherein a displacement sensor is provided on the connecting plate; a force sensor is arranged between the lug ring and the connecting plate; and a servo valve is communicated with the cylinder body.",
    "5. The 4-degree-of-freedom leg mechanism of claim 1, wherein the thigh longitudinal-swing assembly comprises a protective cover, a hydraulic cylinder and a servo valve; and the hydraulic cylinder and the servo valve are sleeved in the protective cover; a cylinder body of the hydraulic cylinder is communicated with the servo valve; the servo valve is communicate with the oil line in the lateral-swing shaft; and a cylinder rod of the hydraulic cylinder is hinged to the shank longitudinal-swing assembly through a sliding-block linkage.",
    "6. The 4-degree-of-freedom leg mechanism of claim 5, wherein the sliding-block linkage comprises a sleeve, a sliding block and a push rod; the sleeve is connected to the cylinder body of the hydraulic cylinder; the cylinder rod of the hydraulic cylinder is connected to one end of the sliding block; the sliding block is sleeved in the sleeve; the other end of the sliding block is hinged to one end of the push rod; and the other end of the push rod and the sleeve are hinged with the shank longitudinal-swing assembly, respectively.",
    "7. The 4-degree-of-freedom leg mechanism of claim 1, wherein the shank longitudinal-swing assembly comprises an outer cylinder, an inner rod, a damping spring and a foot end; the inner rod is inserted into the outer cylinder; an upper end of the inner rod is provided with a limit ring; a lower end of the inner rod is fixedly connected to the foot end; the damping spring is arranged between the foot end and the outer cylinder; and the damping spring is sleeved on the inner rod.",
    "8. The 4-degree-of-freedom leg mechanism of claim 7, wherein the foot end comprises an ankle, a fixed part and a positioning foot; the ankle is connected to the inner rod and the fixed part, respectively; the fixed part is provided with a groove for accommodating the positioning foot; and the positioning foot is fixedly connected to the fixed part via a bolt.",
    "9. The 4-degree-of-freedom leg mechanism of claim 8, wherein a six-dimensional force sensor is arranged between the ankle and the inner rod; the positioning foot is a rubber cylinder; and a groove is arranged on a cylindrical surface of the positioning foot contacting with a ground."
  ],
  "description_excerpt": "This application relates to components of bionic robots, and more particularly to a lightweight 4-degree-of-freedom leg mechanism of a bionic quadruped robot.\n\nWith the rapid development of science and technology in the 21st century, high-end mobile equipment, such as construction machinery, metallurgical machinery, aircraft, auxiliary exoskeleton and quadruped bionic robots has been extensively researched and applied. The high-end mobile equipment mainly moves by means of wheels and feet. By comparison, the foot-based motion has better adaptability to the unstructured environments and high leg flexibility, and thus is widely appreciated. In terms of the number of legs, the legged bionic robots can be divided into bipedal, quadruped, hexapod and polypod robots, among which the quadruped robot is the most practical, and is widely used in the disaster relief, daily transportation and entertainment. The leg structure of the quadruped bionic robot is usually driven by electric power, pneumatic power and hydraulic power. The hydraulic drive has high power-to-weight ratio, good stability, small reversing impact, fast response and large thrust. Therefore, the study of integrated leg mechanism of the hydraulically-powered quadruped bionic robot is of great importance.\n\nCurrently, the hydraulic drive of the leg mechanism of the quadruped robot is mainly realized by means of an external pipeline, and the arrangement of the leg mechanism is relatively scattered. Such leg mechanism has large joint weight, small motion range and insufficient driving ability, and thus the motion accuracy and response speed are limited.",
  "cpc": [
    "B62D 57/032",
    "B25J 13/085",
    "B25J 17/0258",
    "B25J 19/0091",
    "B25J 9/144"
  ],
  "ipc": [
    "B25J 17/02",
    "B62D 57/032"
  ],
  "assignees": [
    "UNIV YANSHAN"
  ],
  "inventors": [
    "YU BIN",
    "BA KAIXIAN",
    "YANG JIANKUI",
    "ZHU QIXIN",
    "HUANG ZHIPENG",
    "YUAN LIPENG"
  ],
  "filing_date": "2021-04-02",
  "publication_date": "2021-10-12",
  "grant_date": "2021-10-12",
  "priority_date": "2020-05-19",
  "application_number": "US-202117221474-A",
  "family_id": "71655182",
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}