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SMA Hexapod

Personal Project Proposal

Ryland Charron

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Overview

Project Impact
Design Objectives
SMA Wires
Models
Electronics Design
BOM

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Project Impact

The field of soft robotics seeks new methods of robot development through the exploration of compliant mechanisms, biologically inspired systems, and novel material properties. “Soft” machines tend to be lighter, safer, and more robust than their traditional counterparts, and often can exhibit behaviors seen in natural systems.

Shape Memory Alloy (SMA) materials have seen minimal use in robotic actuation, but could be used to develop quiet and lightweight actuation systems.

This project seeks to demonstrate the viability and limitations of SMA actuation in a hexapod robot, while furthering the experimenter's knowledge of SMA material and PCB design.

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Design Objectives

Design, Prototype, and Test a hexapod robot actuated entirely by Shape Memory Alloy wires.
Minimize weight and power consumption.

Project is a Success if:

Robot walks forward a distance greater than its body long axis length under the power of SMA wire actuation.
Robot operates untethered.

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Shape Memory Alloy (SMA) Wires (1/2)

A combination of metals which exhibit pseudoelastic properties.
Deformable when cool but return to original shape when heated.
Used in automotive valves, vibration damping, braces, sunglasses frames.
Robotic uses limited due to low frequency and low energy efficiency.

(Left) https://en.wikipedia.org/wiki/Shape-memory_alloy

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Shape Memory Alloy (SMA) Wires (2/2)

This project uses Flexinol Low Temperature wire (Right)
NiTixx Alloy
200um (0.008”) diameter
Actuates at 600-700mA
Contraction force of 500g (1.1lb)
~4% deformation achieved in ~1s.

(Left) https://www.imagesco.com/nitinol/wire.html and experimental data

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Prototyping (1/4)

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Prototyping (2/4)

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Prototyping (4/4)

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Prototyping (4/4)

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Physical Design (1/2)

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Electronics Design (1/2)

x4

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Electronics Design (2/2)

RPi Zero Plugs Directly into 40p Header
Manufactured by JLCPcb
Manually Soldered

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BOM

https://docs.google.com/spreadsheets/d/1T3ETzJQ25yEpU4xL6UDwDXOrOz0rNmrhceP2yH12BJA/edit?usp=sharing

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Conclusion

I am requesting

$200 in personal project funding for material cost
A one semester project lifetime
To retain ownership of the robot and project materials

If project is successful and I am able to attend, I would like to showcase the project at Imagine RIT 2023 with the MDRC booth.

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Thank You

Questions