Chito-bot
chi·to·bot
Bio-Composite Hexapod
Investigating material compliance and structural integrity in bio-composite hexapods.
HYPOTHESIS
Standard robotics relies on permanent, non-biodegradeable materials (like aluminum, ABS plastic) that outlast their functional lifecycle, contributing to e-waste. This project proposes a Transient Robotics Framework: hardware designed to structurally degrade in sync with its obsolescence.
RESPONSE
The goal was to engineer a functional chassis entirely from Chitosan (seafood waste) that offers the structural rigidity required for locomotion but dissolves upon contact with specific environmental enzymes.
ROLE
Industrial Design + Mechanical Packaging
TOOLS:
I used a standardized 18-DOF servo platform to conduct comparative testing between PLA (plastic) and Chitosan (bio-composite). By keeping the electronics constant, I could isolate the material performance variables.
FOCUS:
Soft Roborics, Component Packaging, Bio-mimicry
Engineering a Bio-composite Chasis
The core challenge was tolerance management. Unlike precision-machined metal, organic bio-composites warp and fluctuate with humidity.
I developed a composite recipe using Chitosan and Sodium Alginate, laser-cut into modular plates to form the hexapod’s body. Integrating 12 servo motors onto this organic shell required designing custom mounting points that distributed torque evenly, preventing the brittle chassis from cracking under the motor's load.
Bio-composite sheet fabrication Dehydration Power Distribution + Signal Routing Benchtop Kinematic Validation
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To engineer a biopolymer capable of sustaining mechanical loads without brittle fracture, I developed a custom composite recipe.
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Matrix: Chitosan (Chitin derivative).
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Plasticizer (Gum Arabic): Increases flexibility and prevents delamination by reducing the glass transition temperature of the composite.
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Cross-linker (Hydrolysable Tannins): Sourced from Coconut Husk extract, tannins chemically bond the Chitosan chains, increasing water resistance and surface hardness similar to leather tanning.
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Fabrication: Kneaded and rolled into a sheet. Dehydrated. Laser cut custom parts.
Topological Optimization & Material Formulation
Finite Element Analysis (FEA):
Static stress
Max stress (0.971 MPa) remains localized at the servo horn mount, confirming the bio-composite arm geometry is well within the elastic limit.Displacement
Max deflection (0.049 in) occurs at the distal tip. This calculated compliance provides essential mechanical damping for granular terrain navigation without compromising gait kinematics.Shape Optimization
Minimize mass while maintaining structural integrity for a 2.5D fabrication process (laser cutting).
68% mass reduction from original chitosan design to shape optimization iteration (from ~0.025 oz to 0.008 oz)
(left: original acrylic leg, middle: redesigned leg, right: space optimized form)
Spatial Optimization time-lapse of the subtractive solver iteratively removing 68% of non-structural mass to reveal the optimal load-bearing geometry (Digital Wolff’s Law)Optimization identified an organic structure that maintains a Safety Factor > 2.0 under gait loads.
Field Validation
The robot was deployed in littoral (shoreline) environments to test material durability.
- Locomotion Testing: Used a standard 18-DOF hexapod kinematic model to test the fatigue limit of the Chitosan plates. The organic chassis successfully sustained operation for 4+ hours on granular terrain without delamination.
- Environmental Resilience: The chassis withstood abrasion from sand and salt spray during the operational window, validating Chitosan as a viable alternative to PLA for short-lifecycle robotic deployments
Executive Review: Presented prototype to Hyundai Motor Group and Kia leadership to validate bio-composite viability for next-generation automotive interiors.
Chitobot displayed: Sustainable Futures, Co-creating with Nature - 2022