Enabling accessible prosthetic hands
What is our goal 🚀
The EnHands student group aims to develop affordable upper limb prostheses (hand prostheses) for the developing world. We plan to develop a prototype and work together with organisations such as the Naya Qadam Trust, who have experience in providing amputees with low-cost leg prostheses, to help with getting the prostheses to people who need them.
About us 👩🔧👩🚀🦸♀️🧜
EnHands was founded in May 2022 and was officially accredited as a TUM student group in July 2022. The group originates from a group of students participating in the Cybathlon Challenge course and currently consists of students from Mechanical Engineering, Robotics, and Informatics related study programs. Organisationally, EnHands is part of the Munich Institute of Robotics and Machine Intelligence (MIRMI).
V2 Functional Prototype
Our newest functional prototype is our most sophisticated development to date: Three different grasping types are provided by mechanical fingers produced from sheet metal, while the outside gets a realistic appearance via a silicone glove.
- Product Overview
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- What it is: Affordable, functional, and cosmetically appealing hand prosthesis for forearm amputees.
- Who it's for: Designed for forearm amputees, especially in low-income countries, who seek both functionality and aesthetic appeal at low cost.
- Cost: < $50
- Features
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- Affordable materials
- Locally manufactured
- Lightweight and compact
- Enhanced actuation
- Easy-release mechanism
- Materials
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- For the mechanism structure, we consider durable, lightweight materials like sheet metal.
- For the glove, we use silicone due to its flexibility, comfort, and human-like appearance.
- Prototyping and Development Process
- We began by focusing solely on functionality with essential grips. We are now working on combining both functional and cosmetic elements for improved aesthetics and usability.
Cosmetic Hand
The Cosmetic Hand is designed to offer both a natural appearance and functional capabilities, focusing on aesthetics and comfort. Here are the key features:
- Origin
- Based on our experiences with 3d-printing fully rigid cosmetic hands, we wanted to add a bit of low-tech gripping functionality.
- Material
- The cosmetic hand combines a rigid PLA core for stability with a soft, grippy silicone outer layer molded to resemble a natural hand. The silicone's shore hardness is set at 30 for a balance between realism and comfort.
- Degrees of Freedom
- The hand features a guitar capo spring mechanism for controlled movement, providing one degree of freedom. Additionally, a second-degree of freedom wrist mechanism, similar to the V1 prototype, offers rotation and adaptability for various tasks.
- Design Philosophy
- The cosmetic hand blends aesthetics and functionality. The silicone outer layer's lifelike appearance enhances user confidence, while its comfortable grip makes daily activities easy. The adjustable wrist mechanism adds versatility to suit different situations.
V1 Functional Prototype
As a starting point, we decided to build a prosthetic hand that is the size of the average woman's hand which can perform the most important grasping types. According to research, these are the ”pinch grasp” and the ”power grasp”, since they enable a person to do most of their everyday tasks such as grabbing tools, cooking or housekeeping tasks.
- Origin
- Parts of the mechanics are inspired by the LN4 hand, but with a deeper focus on anthropomorphic design and patient acceptance.
- Material
- We use polylactic acid (PLA) due to its lightweight and stiff material properties. 3D printing is our main manufacturing method during the prototyping phase, however in future designs we want to switch to more reliable methods which are better suited for developing nations.
- Degrees of Freedom
- A 3-DoF thumb, two 1-DoF fingers and a 1-DoF 360° rotational wrist, all of which are actuated passively.
- Design Philosophy
- Discrete passively actuated grasping positions. Anthropomorphic appearance. Rigid impact-resistant parts. Low maintenance.