Flexibly-driven small underwater robot and driving method thereof

{
  "publication_number": "US11806871B2",
  "country": "US",
  "kind": "B2",
  "title": "Flexibly-driven small underwater robot and driving method thereof",
  "abstract": "Disclosed are a flexibly-driven small underwater robot and a driving method thereof. The underwater robot provided by the invention comprises a driving module and a propelling module. Two propelling modules are designed at head and tail portions, and the driving module is arranged between the two propelling modules. A rib plate in the driving module comprises a carbon fiber plate matrix and a piezoelectric fiber sheet; and a shape of the carbon fiber plate matrix is optimized by width change and hole digging. The propelling modules comprise a head propelling module and a tail propelling module, and the head propelling module and the tail propelling module are both propelled through a one-way valve. According to the invention, two modes of the pre-compression rib plate are adjusted through the piezoelectric fiber sheet, so that a volume of an internal cavity is changed, and jet propelling is carried out.",
  "claims": [
    "1. A flexibly-driven small underwater robot, comprising a main body part, a driving module (2) and a skin (4), wherein the driving module (2) comprises a plurality of rib plates; the rib plates surround the main body part; two ends of the rib plates are respectively fixed with two ends of the main body part; in an initial state, the rib plates are in a convex or concave pre-bent state; the annular and elastic skin (4) is wrapped on outer sides of all the plurality of rib plates, and a water pumping and draining chamber is formed in a middle portion of the main body part; a head end of the main body part is provided with a water inlet, and a tail end of the main body part is provided with a water outlet; the water inlet and the water outlet are both communicated with the water pumping and draining chamber; the water inlet and the water outlet are both provided with a one-way valve; an input port of the one-way valve on the water inlet is arranged outwardly; an input port of the one-way valve on the water outlet is arranged inwardly; the rib plates comprise a piezoelectric sheet (2 - 1) and a matrix plate (2 - 2); two ends of one side surface of the matrix plate (2 - 2) are both fixed with the piezoelectric sheet (2 - 1); when electrified, the piezoelectric sheet (2 - 1) is extended or retracted along a length direction of the matrix plate (2 - 2); and when the piezoelectric sheet (2 - 1) is applied with forward and inverse periodic voltages, corresponding rib plates are periodically switched between the concave state and the convex state to drive a volume of the water pumping and draining chamber to be changed periodically; and the main body part comprises a head propelling module (1), a connecting module (3) and a tail propelling module (5) which are sequentially arranged and fixedly connected together; and the matrix plate (2 - 2) has a gradually changed width structure with two narrow ends and a wide middle; and the matrix plate (2 - 2) is provided with a hole in a position where the piezoelectric sheet (2 - 1) is mounted.",
    "2. The flexibly-driven small underwater robot according to claim 1, wherein the head propelling module (1) comprises a fairing (1 - 1), a head platform (1 - 4), a water inlet pipe (1 - 3) and a head skin adhesive portion (1 - 2) which are fixed together; the fairing (1 - 1) is partially spherical; the head platform (1 - 4) is arranged on an inner side of the fairing (1 - 1); the head skin adhesive portion (1 - 2) is located on an outer side surface of the head platform (1 - 4) and connected with a corresponding edge of an inner side surface of the skin (4); the water inlet pipe (1 - 3) is arranged in a central position of an outer side surface of the fairing (1 - 1) and communicated with the water pumping and draining chamber; the tail propelling module (5) comprises a tail platform (5 - 1), the one-way valve (6), a water outlet pipe (5 - 2) and a tail skin adhesive portion (5 - 3); the tail skin adhesive portion (5 - 3) is located on an outer side surface of the tail platform (5 - 1) and connected with a corresponding edge of the inner side surface of the skin (4); the water outlet pipe (5 - 2) is arranged in a central position of an outer side surface of the tail platform (5 - 1) and communicated with the water pumping and draining chamber; edges of opposite side surfaces of the head platform (1 - 4) and the tail platform (5 - 1) are both provided with a plurality of inserting slots; the inserting slots are connected with end portions of corresponding rib plates in an inserted manner; a joint between the rib plate and the inserting slot is adhered; a depth direction of the inserting slot is perpendicular to the opposite side surfaces of the head platform (1 - 4) and the tail platform (5 - 1); and interiors or end portions of the water inlet pipe (1 - 3) and the water outlet pipe (5 - 2) are provided with the one-way valves (6).",
    "3. The flexibly-driven small underwater robot according to claim 1, wherein the one-way valve (6) corresponding to the water outlet comprises a diversion pipe (6 - 1), a valve cover (6 - 3) and a connecting shaft (6 - 2); an edge of an end portion of the diversion pipe (6 - 1) and an edge of the valve cover (6 - 3) are rotatably connected through the connecting shaft (6 - 2); a torsion spring is arranged between the valve cover (6 - 3) and the diversion pipe (6 - 1); under a condition of not being subjected to an acting force of a water flow, the valve cover (6 - 3) abuts against the end portion of the diversion pipe (6 - 1) under an elastic force provided by the torsion spring; the diversion pipe (6 - 1) is closed when the valve cover (6 - 3) abuts against the end portion of the diversion pipe (6 - 1); the valve cover (6 - 3) in the one-way valve corresponding to the water inlet is located at one end of the diversion pipe (6 - 1) close to the water pumping and draining chamber; and the valve cover (6 - 3) in the one-way valve corresponding to the water outlet is located at one end of the diversion pipe (6 - 1) far away from the water pumping and draining chamber.",
    "4. The flexibly-driven small underwater robot according to claim 1, wherein the rib plates are evenly distributed along a circumferential direction of a central axis of the main body part.",
    "5. The flexibly-driven small underwater robot according to claim 1, wherein in the initial state, the rib plates are in the convex state; and the two piezoelectric sheets (2 - 1) in the rib plate are respectively located at two ends of an outer side surface of the matrix plate (2 - 2).",
    "6. The flexibly-driven small underwater robot according to claim 1, wherein in the initial state, the rib plates are in the concave state; and the two piezoelectric sheets (2 - 1) in the rib plate are respectively located at two ends of an inner side surface of the matrix plate (2 - 2).",
    "7. The flexibly-driven small underwater robot according to claim 1, wherein an inner side surface of the skin (4) is adhered to outer side surfaces of the rib plates; and two ends of the skin (4) are hermetically connected with two ends of the main body part by adhering.",
    "8. A driving method of the flexibly-driven small underwater robot according to claim 1, wherein all piezoelectric sheets are applied with a periodic voltage to control the rib plates to be switched periodically between the convex state and the concave state, so that the volume of the water pumping and draining chamber is changed periodically; when the volume of the water pumping and draining chamber is reduced, the water inlet located at the head end of the main body part sucks water from an external environment; and when the volume of the water pumping and draining chamber is increased, the water outlet located at the tail end of the main body part ejects water to the external environment, thus forming a propelling force."
  ],
  "description_excerpt": "The present invention belongs to the field of underwater robots, and particularly relates to a flexibly-driven small underwater robot and a driving method thereof.\n\nAt present, rigidly-driven underwater robots at home and abroad usually have two modes, which are namely propeller driving and hinged rigid connection respectively. Although these two driving modes have the advantages of simple structure and easy control in large-scale driving structures, these two driving modes have the disadvantages of low energy utilization, low flexibility and high noise when applied to small underwater robots. Low energy utilization means poor endurance. As an important factor of underwater detection, too large noise leads to more easy exposure to passive sonar detection. As a core of rigid driving, a motor drives a transmission mechanism to drive, which also reduces a flexibility of a machine. Moreover, with the increase of a number of transmission mechanisms, the structure of the underwater robots is complicated, and manufacturing and maintenance costs of the underwater robots are increased.\n\nTherefore, in order to improve the driving efficiency, reduce the driving noise and increase the invisibility of the small underwater robots, we adopt a flexible driving mode and propose a small underwater robot, which not only improves the energy utilization rate and reduces the movement noise, but also improves the accurate control ability of the robots, simplifies the structure, and reduces movement and maintenance costs of the robots.",
  "cpc": [
    "B25J 9/142",
    "B25J 9/0015",
    "B63C 11/52",
    "B63G 2008/002",
    "B63G 2008/004",
    "B63G 8/001",
    "B63G 8/08",
    "B63H 11/02"
  ],
  "ipc": [
    "B25J 9/00",
    "B25J 9/14",
    "B63C 11/52"
  ],
  "assignees": [
    "Zhejiang University ZJU"
  ],
  "inventors": [
    "Chunli Zhang",
    "Yihong Han"
  ],
  "filing_date": "2023-03-13",
  "publication_date": "2023-11-07",
  "grant_date": "2023-11-07",
  "priority_date": "2022-03-14",
  "application_number": "US-202318183136-A",
  "family_id": "81598634",
  "cited_by_count": 0,
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}