BIOMIMETRIC CRAB

Bill Dwyer

Joe Mead

Shaynae Moore

Casey O’ConnellWEEK 3

Pinching motion needs to be quicker than flexion and extension motion.

We are modeling the Blue Crab Pneumatically powered 3 muscles per claw Running of RIT house air

Design for 40 psi (60 psi upper limit.) Aquarium will be provided and sized according to our

size requirements. Low risk for exploding surgical tubing.

High cyclical repeatability Governing equations for McKibben muscles.

BRAINSTORMING: PROJECT KNOWN'S (UPDATE)

BRAINSTORMING: PROJECT UNKNOWNS (UPDATE)

What materials will the crab be made out of? How will the crab be encased? Will our device move through locomotion? What will the length of our muscles be? How will the crab be designed so it will remain flush on the aquarium

floor Will there be a cabin that will house the muscles or will they be located

on the underbelly of our device? How will the range of motion intervals be incorporated

Example (antagonistic muscle pairs?) Blue Crab Species information and movement. How rigid/buoyant will the umbilical chord become after pressurizing.

ENGINEERING

SPECIFICATIONS

(SEE SPREAD

SHEET)

PROJECT RISKS

(SEE SPREAD

SHEET)

CONCEPT DEVELOPMENTPreliminary Biomimetic Crab design

•Pincher

• Claw

•Wrist

NOTE:

•This is underside of assembly to hide Mechanics.

•The Left and right assemblies are mirror copies.

•Both assemblies will function simultaneously and individually.

CONCEPT DEVELOPMENT

•The spring creates force required to open the pincher and keep it in the rest phase.

•The McKibben muscles creates the force required to close pincher

CONCEPT DEVELOPMENT

•The Pincher control line passes directly over the wrist joint to minimize deflection in wrist articulation

•The spring provides force that keeps wrist at neutral or zero angle of rotation

•The wrist is operated by two McKibben muscles to create positive and negative rotation

CONCEPT DEVELOPMENT

Frame or Platform Design

•Simply flat plate design for easy mount of;

•Arm Assemblies

•Legs Assemblies

•McKibben muscles

•Aesthetic cover plates

CONCEPT DEVELOPMENT

Aesthetic Covering

•Cast fiberglass, foam or gel pieces

•Rubber “suit” the frame fit inside

•Worst case paint entire Crab