Modular Lower Limb Exoskeleton
This research project aims to design and fabricate a lower extremity exoskeleton prototype for medical applications such as physical therapy, gait rehabilitation, muscle training, and walking assistance. The exoskeleton prototype incorporates three configurations to fit the needs of the user: hip-only, hip-knee, and hip-knee-ankle. Each configuration utilizes a combination of the hip, knee, and ankle modules, with individual high-torque DC motorized rotational axes dedicated to each joint.
This modular design allows for customization to cater to specific needs and can be adjusted for different users. The exoskeleton’s composite structure construction, involving a sheet metal aluminum and 3D-printed PLA core and carbon fiber epoxy outer skin, makes it lightweight (13.5kg) and suitable for medical applications. The assembled modules met the adjustable targets set in the design criteria and demonstrated the feasibility of this design concept.
The exoskeleton prototype shows promising potential for medical applications, and the incorporation of individual motorized rotational axes dedicated to each joint adds to its effectiveness and usability.
Team members: Junlin (Hugo) Chen, Asteya Laxmanan, Sannad Shabbar
Hip Exoskeleton
This project is dedicated to enhancing the lives of individuals with motor disabilities, spanning a wide range of age groups and conditions. Our focus is centered on a hip exoskeleton designed to address the critical need for cost-effective, lightweight, and comfortable assistive devices for daily activities.
The hip exoskeleton combines lightweight and affordability while ensuring the utmost wearer comfort during various movements. It boasts remarkable structural strength and torque power, making it a highly effective exoskeleton in aiding individuals with lower limb impairments. With two degrees of freedom, the exoskeleton generates hip movement trajectories in the sagittal plane, facilitating activities like walking and sit-to-stand transitions.
Incorporating a compact control system featuring high-torque DC motors, mini-PC, microcontroller, and intermediate boards, the exoskeleton optimizes both size and performance. Comprehensive experimental studies have rigorously assessed its capabilities, confirming its effectiveness in assisting with walking and sit-to-stand motions at variable speeds.
This hip exoskeleton project offers an adaptable and affordable solution with the potential to significantly enhance mobility and quality of life for individuals with motor disabilities. Further, the projects serves as a foundation to incorporate other joints and explore other control strategies that utilizes its own software to control each motors.
Team members: Eric Kwan, Jose Jaime Esquivel Patricio, Dhurba Shresth, Sai Hein Si Thu, Ana Isabel Espinosa Agundis
Knee Exoskeleton
This research project aims to develop a semi-rigid knee chain exoskeleton intended to assist individuals with lower limb disabilities or injuries. The design incorporates a Bowden cable system to improve human-robot interaction by relocating leg-mounted motor actuators. The design of each individual link went through FEA analysis to maximize strength and weight while preventing cable misalignments.
Components were fabricated using 3D printing, and various thermoplastic materials, such as carbon fiber infused polyethylene terephthalate glycol (PETG-CF) and thermoplastic polyurethane (TPU), were employed for strength and flexibility. Functionality testing, including different user positions and walking tests, demonstrated the exoskeleton's effectiveness.
Future work will involve further refinements of the knee chain design, integration with a hip exoskeleton system, and additional control developments. The goal is to create a more comprehensive and effective solution for assisting individuals with lower limb disabilities, ultimately improving their mobility and quality of life.
Ankle Exoskeleton
This project presents a new prototype of an ankle-foot exoskeleton designed to address the growing interest in smaller, portable ankle-foot assistive devices that individuals can use.
The project's fabricated components, including the ankle brace and pressure insoles, were designed for affordability, low material usage and ease of mass production while maintaining structural integrity, comfort, and support. The material used were 3D printed with thermoplastic polyurethane (TPU) and polylactic acid (PLA) combined with zinc-nickel hinge joints to create a one-degree-of-freedom (DOF) support system.
A pressure insole system consisting of a silicone-based pressure mold, pressure force sensors, microcontroller, and PC was developed to map foot pressure during walking. The pressure insole sensor was subjected to a standing and step motion to measure foot pressure. The ankle brace was also subjected to actuation tests via a torque moto to obtain ankle trajectory profiles for various walking speeds.
Future improvements aim to streamline the brace design, enhance joint connections, and integrate the ankle brace with knee and hip exoskeletons for comprehensive testing. This research contributes to the development of lightweight and cost-effective ankle-foot assistive devices, improving the mobility and quality of life for individuals with lower limb disabilities.