Robotic fish

Patent metadata

Field	Value
Publication number	US-2021276678-A1
Application number	US-202017029547-A
Country	US
Kind code	A1
Filing date	Sep 23, 2020
Priority date	Mar 5, 2020
Publication date	Sep 9, 2021
Grant date	—

Abstract

A robotic fish includes a front body, a rear body that includes a first segment and a second segment, and a driving unit. The first segment has a front engaging portion projecting toward and pivotally connected to the front body, and a rear engaging portion formed with a recess that recedes toward the front body and pivotally connected to the second segment. The driving unit includes a motor disposed in the front engaging portion, and a shaft extending along a dorsoventral axis and connecting the motor and the rear connecting portion. A ratio of a distance between the shaft and a foremost edge of the front engaging portion to a distance between the foremost edge and an extreme point of the recess ranges from 0.075 to 0.75.

First claim

What is claimed is:

1 . A robotic fish comprising:
a front body having a rear connecting portion; a rear body disposed behind said front body in a swimming direction, in which said robotic fish swims, and including
a first segment having
a front engaging portion that projects toward said front body in the swimming direction, that is connected to said rear connecting portion, that overlaps said rear connecting portion along a dorsoventral axis of said robotic fish, and that has a foremost point in the swimming direction, and
a rear engaging portion that is opposite to said front engaging portion in the swimming direction, and that is formed with a recess receding toward said front body in the swimming direction and having an extreme point closest to said front engaging portion in the swimming direction, and

a second segment having a front connecting portion that is connected to said rear engaging portion and that overlaps said rear engaging portion in a direction parallel to the dorsoventral axis, and a rear end opposite to said front connecting portion in the swimming direction,
a caudal fin connected to said rear end of said second segment; a first driving unit configured to drive said front body to swing left and right relative to said first segment, and including a motor that is disposed in said front engaging portion, and a shaft, said shaft having a central axis that extends along the dorsoventral axis, a first end that is connected to said motor, and a second end that is fixedly connected to said rear connecting portion; a center-of-gravity (CG) adjusting unit disposed in said front body, and including a weight that is movable in one of the swimming direction and a posterior direction opposite to the swimming direction to adjust a center of gravity of said robotic fish; a second driving unit disposed in said front body, connected to said CG adjusting unit, and configured to drive said weight to move in one of the swimming direction and the posterior direction; a third driving unit disposed in said front connecting portion of said second segment, and configured to drive said first segment to swing left and right relative to said second segment; and a controller disposed in one of said front body and said rear body, electrically connected to said first, second and third driving units, and configured to control operation of said first, second and third driving units, wherein a ratio of a first distance between the central axis of said shaft and a first imaginary line parallel to the central axis of said shaft and passing through said foremost point of said front engaging portion to a second distance between the first imaginary line and a second imaginary line parallel to the central axis of said shaft and passing through said extreme point of said recess of said rear engaging portion ranges from 0.1 to 0.75.

2 . The robotic fish of claim 1 , wherein said rear connecting portion of said front body is formed with a recess receding in the swimming direction, and has two projecting blocks that are opposite to and spaced apart from each other along the dorsoventral axis to define said recess of said rear connecting portion,
wherein said second end of said shaft is fixedly connected to one of said projecting blocks, and said front engaging portion includes a supporting rod extending along the dorsoventral axis and being connected rotatably to the other one of said projecting blocks.

3 . The robotic fish of claim 2 , wherein:
a cross section of said rear connecting portion on a frontal plane between said projecting blocks has a first rear side facing said front engaging portion and having two line segments that interconnect substantially at a center of said first rear side to form a single angle pointing in the swimming direction; a cross section of said front engaging portion on the frontal plane has a first front side facing said rear connecting portion and having two lateral chamfers that do not interfere with said rear connecting portion; a cross section of said rear engaging portion on the frontal plane has a second rear side facing said front connecting portion and being a simple polygonal chain that has two angles substantially pointing in the posterior direction and being laterally spaced apart from each other; a cross section on the frontal plane of said front connecting portion has a second front side facing said rear engaging portion and having two lateral chamfers that do not interfere with said rear engaging portion; said rear connecting portion further has a first rear edge in a top view of said robotic fish, and the first rear edge faces said front engaging portion and is a convex curved line; said front engaging portion further has a first front edge in the top view of said robotic fish, and the first front edge faces and does not interfere with said rear connecting portion and is one of a straight line, a concave curved line, and a simple polygonal chain that has two angles substantially pointing in the swimming direction and being laterally spaced apart from each other; said rear engaging portion further has a second rear edge in the top view of said robotic fish, and the second rear edge faces said front connecting portion and is a convex curved line; and said front connecting portion further has a second front edge in the top view of said robotic fish, and the second front edge faces and does not interfere with said rear engaging portion and is one of a concave curved line, a straight line, and a simple polygonal chain that has two angles substantially pointing in the swimming direction and being laterally spaced apart from each other.

4 . The robotic fish of claim 2 , wherein:
a cross section of said said rear connecting portion on a frontal plane between said projecting blocks has a first rear side facing said front engaging portion and being a concave curved line; a cross section of said front engaging portion on the frontal plane has a first front side facing said rear connecting portion and being a convex curved line that does not interfere with said rear connecting portion; a cross section of said rear engaging portion on the frontal plane has a second rear side facing said front connecting portion and being a concave curved line; a cross section of said front connecting portion on the frontal plane has a second front side facing said rear engaging portion and being a convex curved line that does not interfere with said rear engaging portion; said rear connecting portion further has a first rear edge in a top view of said robotic fish, and the first rear edge faces said front engaging portion and is a convex curved line; said front engaging portion further has a first front edge in the top view of said robotic fish, and the first front edge faces and does not interfere with said rear connecting portion and is one of a straight line, a concave curved line, and a simple polygonal chain that has two angles substantially pointing in the swimming direction; said rear engaging portion further has a second rear edge in the top view of said robotic fish, and the second rear edge faces said front connecting portion and is a convex curved line; and said front connecting portion further has a second front edge in the top view of said robotic fish, and the second front edge faces and does not interfere with said rear engaging portion and is one of a concave curved line, a straight line, and a simple polygonal chain that has two angles substantially pointing in the swimming direction and being laterally spaced apart from each other.

5 . The robotic fish of claim 2 , wherein:
a cross section of said rear connecting portion on a frontal plane between said projecting blocks has a first rear side facing said front engaging portion and being a straight line; a cross sect

Assignees

• Univ Nat Taipei Technology

Inventors

• Yao Leeh-Ter
• Lin Huei-Jyuan
• Yeh Li-Yuan
• Tsai Yu-Chieh
• Jheng Yu-Siao

Classifications

• B63H1/36 Primary

  swinging sideways, e.g. fishtail type · CPC title

• B63G8/08 Primary

  Propulsion ({schnorkels B63G8/36;} nuclear propulsion B63H21/18; submerged exhausting apparatus F01N13/12) · CPC title

• B63G8/001 Primary

  Underwater vessels adapted for special purposes, e.g. unmanned underwater vessels; Equipment specially adapted therefor, e.g. docking stations (self-propelled or direction controlled diving chambers with mechanical link to a base B63C11/42) · CPC title

• B63G2008/004

  autonomously operating · CPC title