Robotic Fish Steering via Parallel Mechanism
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Solution Overview
Problem
Existing robotic fish designs for clearing algae and unwanted plant growth in water bodies face challenges with high costs and limited affordability due to complex mechanical linkages and the need for multiple servo motors in pectoral fin designs, which also restrict multiple rotational degrees of freedom.
Innovation Solution
A parallel mechanism with five rigid bars and five joints, actuated by two servo motors, allows for two degrees of freedom, mimicking the motion of a fish's pectoral fin, enabling efficient steering and maneuverability at a lower cost by using a laminate fabrication process that allows for multiple rotational degrees of freedom.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a robotic pectoral fin design uses eight servo motors per fin with rigid bars and latex sheet, then the steering performance is improved, but the cost increases significantly
Solution Approach 1:
The pectoral fin is divided into multiple rigid bars (first bar, second bar, third bar) connected by joints, with each bar having specific functional segments. The first and second bars are actuated by servo motors while the third bar provides structural support, creating a segmented actuation system that reduces the total number of motors needed while maintaining steering performance.
Solution Approach 2:
The parallel mechanism structure serves multiple functions simultaneously: it provides steering control, enables multiple rotational degrees of freedom, and maintains structural integrity. The same mechanism that steers the fin also provides the rotational flexibility needed for natural fish-like movement patterns, eliminating the need for separate control systems.
2Adaptability or versatility
If current solutions use complex mechanical linkages with precision-machined parts to enable multiple rotational degrees of freedom, then the maneuverability is improved, but the manufacturing complexity and cost increase
Solution Approach 1:
The mechanism incorporates multiple rotational degrees of freedom through joints connecting the rigid bars, allowing dynamic adjustment of the fin's orientation during movement. The joints enable the fin to rotate and orient itself naturally during swimming maneuvers, providing adaptability without requiring complex precision-machined linkages.
Solution Approach 2:
The patent changes the design parameters by using standard servo motors with configurable angular positions rather than custom precision-machined components. The controller adjusts the angular positions of the servo motors to achieve desired maneuvering patterns, allowing flexibility through software control rather than complex mechanical design.
3Device complexity
If traditional robotic fish designs use simple propulsion mechanisms, then the cost is reduced, but the swimming speed and turning capability are limited
Solution Approach 1:
The patent replaces simple mechanical propulsion with a more sophisticated parallel mechanism that uses two servo motors to control multiple rigid bars. This substitution enables complex swimming patterns including forward movement and sharp turns, achieving higher speeds and better maneuverability while keeping the overall system relatively simple.
Data Source
AI summary
In one aspect, a device for providing propulsion in water is provided by the present disclosure. The device includes a parallel mechanism including at least five rigid bars and at least five joints, each joint being positioned between two of the rigid bars and configured to allow movement of the at least five rigid bars, a first servo motor coupled to a first rigid bar included in the at least five rigid bars, a second servo motor coupled to a second rigid bar included in the at least five rigid bars, and a controller coupled to the first servo motor and the second servo motor and configured to actuate the first servo motor and the second servo motor according to a predetermined pattern.