Wearable Robotics

Wearable Robotics for Augmented Human Mobility & Functionality

ACADEMIC | Capstone Project | Product design | Computer-aided Design | Team project

Timeline

Oct 2024 - Jun 2025

TYPE

Academic

Engineering Design

Team Project

RoLE

Main Mechanical Designer

DELIVERABLEs

3D CAD model

Analysis

Physical Prototype

TOOLS

SolidWorks

Ansys

MATLAB

Arduino

ChatGPT

This is an engineering design project that aims to create a device with Variable Stiffness Actuators (VSAs) to help patients in knee rehabilitation exercises. This is the capstone project for my Bachelor Degree at VinUniversity, and a collaboration of four students from different engineering background.

problem

Knee rehabilitation is an important part of the recovery process for patients after an accident or surgery. This is a slow and inefficient process and requires a lot of support from clinicians. This heavy reliance on clinical expertise not only limits scalability but also places significant strain on healthcare resources.

goal

Design a device to replicate the support from clinicians during knee rehabilitation exercises by using Variable Stiffness Actuators.

Members & Responsibilities

Supervisor Professor

Provide assistance and guidance for the team. Help members navigate through obstacles to receive the desired result.

Duy-Quang (it's Me)
Mechanical Design & Analysis. Design the core mechanisms and elements of the device.

Collab in System Control.

Member 2

Manufacturing. In charge of material selections, manufacturing methods and executions.

Collab in System Control.

Member 3

Electrical Design. Responsible for the electrical components, focus on EMG signal processing & data gathering.

Collab in System Control.

Member 4

AI application. Focus on training AI model to predict angle output from inputs of EMG signals.

Collab in System Control.

THE Design PROCESS

I. Initial Research:

We examined current VSAs design via scientific entries to identifying the key features of VSAs:

Key characteristics of VSAs

Adjustable stiffness

Actuator adapts instantly to changing environments.

Elastic Components

Usually a spring. Ensures smooth, flexible movements.

Two motors

Dynamic stiffness control by two motors.

Control & Sensing

Real-time sensing for immediate responsiveness.

II. IdeatION:

Our team came up with the elements for our device based on the research.

Elements of our device

Beams

Consists of 3 main beams: thigh, leg, and drive beam.

Elastic Components

Tension spring attached between the drive beam and the leg beam.

Motors

Two high-torque stepper motors.

Principle

One motor moves beam angle, one adjusts spring position, real-time stiffness adaptation.

Sensing

Measure EMG sensors to get the electrical signals when the user move their legs.

Machine learning

AI model receive EMG signal as inputs and give out according angle.

As the main Mechanical Designer, my responsibilities revolve around design the mechanisms, choosing springs and motors. I also participate in the controlling process, providing mechanical insights.

Early Stage - Low Fidelity Design - SolidWorks

III. Mechanical Design:

After experimenting with different approach in SolidWorks, along with the guidance of our professor, our team decided that we would use two set of ball screw that convert the rotational motions of the motors to linear motions. The linear motions will then be used to control the angle of the drive beam through the principle of the crank-slider mechanism.

Mechanism Design

IV. Analysis & Simulation:

From the design, I create a dynamic model to help calculate the output torque of the device based on the positions of the motors and the leg's angle. I also use MATLAB & ANSYS with the help of ChatGPT to create a simulation of the device to better understand the torque relationship and the beam strength.

Dynamic model

MATLAB Simulation

ANSYS Simulation

V. Prototyping:

With the High Fidelity Design, our team started working on the the physical prototype. The beams will be made by laser cutting MICA plates. The shafts will be made by CNC machines. Other elements will be bought or 3D printed.

Prototype 1.0

Problems & Solutions

Velcro Strap

3D printed strap too brittle, the location of the strap is not user friendly.

Solution

Convert the strap to MICA plates. Relocate the location of the strapping point.

Tolerance

Tolerance make the device is wobbly, with some parts cannot be fitted together.

Solution

Cut a plate with holes in different size to test the tolerance of the MICA plates. Use tapes to test the tolerance of the metal shafts. 3D printed with different size to test.