Alt-Bionics is tackling the challenge of expensive prosthetic limbs by offering affordable bionic hands. Using innovative technology, these hands are designed to be both cost-effective and functional for individuals with below-elbow amputations.
The journey began as a university project aimed at developing a low-cost bionic hand, and since then, Alt-Bionics has continuously pursued its vision with determination and innovation. More on that in this video.
The evolution of the bionic hand from a basic prototype to a product ready for commercial release has been characterized by overcoming challenges and valuable experiences. Our collaboration with Alt-Bionics focused on advancing the device’s hardware and firmware, as well as developing a mobile application for personalized grip customization and calibration. Together, we have realized many objectives and remain dedicated to the continuous enhancement of the product. We invite you to learn more about the contributions of our team in partnership with Alt-Bionics.
Overview of the solution
Let’s start by exploring the holistic solution crafted by Alt-Bionics in collaboration with our team. The system includes a bionic hand that combines practical design with advanced technology, and a user-friendly mobile application for easy control and customization. Now, we’ll take a closer look at how these components work together to form an effective prosthetic solution.
- Bionic Hand Device: A sophisticated machine meticulously attached to the amputee’s body, capable of performing an array of grips. It represents a blend of advanced mechanics and electronics, engineered for reliability and precision.
- Mobile Application: A user-friendly interface that establishes a seamless connection with the Bionic Hand, facilitating control, customization, and monitoring of the device. The app is instrumental in managing predefined grips and creating personalized grip patterns.
- Bluetooth Connectivity:
Bionic Hand Components Detailed:
- Motors and Actuators: These are the driving forces that bring the Bionic Hand to life, ensuring smooth and controlled movements. Think of them as the muscles of a human hand.
- Force Sensitive Resistor (FSR): This sensor measures the force exerted by the prosthetic fingers, allowing for precise control during object manipulation. They work like our sense of touch, allowing the bionic hand to feel and adjust its grip on objects. The integrated force sensors and vibration motors provide real-time haptic feedback, enhancing the user’s tactile experience.
- PCB (Printed Circuit Board): The electronic hub of the Bionic Hand, containing the circuitry for control and monitoring, as well as the Bluetooth module for wireless connectivity. You can think of the PCB as the brain of the bionic hand.
- EQD (Emergency Quick Disconnect): A useful industry standard mechanism that allows for the Bionic Hand to be quickly detached and reattached from the prosthetic socket. Amputees may have one or more devices (grippers, claws, hooks) that use this method. The EQD allows simple switching between these other devices.
- Prosthetic Socket: This component securely attaches the Bionic Hand to the residual limb, providing a comfortable and stable fit.
- Coaxial Plug: This connector facilitates the transmission of signals from the EMG sensors to the PCB, ensuring accurate muscle activity readings.
- EMG (electromyography) Sensors: Two sensors are attached to antagonist muscles: one (the Palmar sensor) for flexion, helping to bend the wrist and fingers towards the palm, and the other one (the Dorsal sensor) for extension, aiding in straightening the wrist and fingers away from the palm, thus translating muscle activity into control signals for the Bionic Hand.
- Battery: A rechargeable power source that fuels the Bionic Hand, ensuring it is always ready for action.
Understanding these components lays the groundwork for a deeper discussion on the crucial hardware enhancements that were necessary for the success of the project.
Rethinking Hand Control Functionality
Our central goal was to elevate the user experience by refining the hand control functions of the bionic hand. While pursuing this, we also had to address a concurrent issue: the initial hardware from the client’s prototype was insufficient for the bionic hand’s growing functional requirements. For an in-depth look at how we navigated these technical challenges, we invite you to read a dedicated blog post focused on the project’s technical aspects.
The initial grip-switching mechanism of the bionic hand operated in a sequential manner. Although functional, this method could be time-consuming, especially for users needing to quickly access specific grips. We introduced a more intuitive and user-friendly approach to grip selection. Instead of cycling through grips sequentially, users can now access their desired grip more swiftly using artificial intelligence controlled electromyography which recognizes a user’s muscle movements and determines which grip they are trying to activate. The user can access 6 different grip patterns at any given time. These six different grips are placed into a set of six memory slots within the firmware.
Each of the six slots can be assigned a specific grip, which can be a default grip provided by the bionic hand or a custom grip created by the user via the mobile app. This allows users to personalize their bionic hand, tailoring it to their daily needs and preferences. The six core grip configurations include Chuck Grip, Fine Pinch, Key Grip, Power Grip, Hook Grip, and Tool Grip. The muscle sensors, both Palmar and Dorsal, play a crucial role in interpreting input and translating it into precise and controlled hand movements.
Grip Control Modes
It incorporates three primary grip control types: Sequential mode, Proportional mode, and AI mode. Each mode is tailored to cater to different user needs and scenarios, providing flexibility and adaptability.
- Sequential Mode is designed for simplicity and ease of use. The Home Position serves as the starting point for all actions, with the Quick Access Grip feature allowing for rapid activation of predetermined grips.
- Proportional Mode offers a more nuanced and precise control mechanism. It incorporates muscle sensor commands, allowing users to increment flex and release directions based on calibrated steps. The Dorsal Flex command increases the flex direction, while the Palmar Flex command increases the release direction. The Force Sensor provides real-time feedback on the applied force, ensuring users have complete control over the bionic hand’s movements. Sequential Mode is like flipping through pages in a book to find your desired grip, while Proportional Mode gives you a slider to adjust the grip with precision.
- AI Mode is meticulously designed to learn and adapt to each user’s unique muscle activity, promising a bespoke experience. Upon engaging AI Mode, the user is guided through exercises, each generating distinct EMG signal patterns. These patterns are carefully captured and mapped by the user to specific grips. When the AI module recognizes one of these patterns in a stream of EMG signals, it activates the grip associated with that pattern.
Our AI module, which at the time of writing this blog is still in active development, demonstrates promising capabilities in distinguishing these unique patterns with a high degree of accuracy. Preliminary results from our proof of concept validate the module’s potential in providing a reliable and intuitive user experience. Explore our dedicated blog post to understand the intricacies of the AI module’s technical implementation, uniquely developed for the Alt-Bionics project, and see how this tailored approach is advancing personalized prosthetic solutions.
The Mobile Application
The application serves as a vital tool, enhancing the interaction between the user and the prosthetic device, and providing a seamless integration and personalization experience. Connecting the bionic hand to the phone is a breeze. The user opens the app, turns on Bluetooth, and selects the device from the list.
Once paired, the mobile application provides users with a comprehensive overview of the available options through the ‘Active Grip’ section, where all the grip patterns currently installed on the bionic hand are displayed and accessible for use.
The ‘Grip Modes’ section allows users to toggle between the three operational modes: AI, Sequential, and Proportional. This feature ensures that the prosthetic hand can be adapted to suit various activities and user needs.
In the ‘Grip Directory’, users have access to both core and customized grip patterns. The application enables the modification of these grips, with sliders for each finger allowing for detailed adjustments.
The ‘Live Mode’ feature provides real-time feedback, ensuring that users can fine-tune each grip to their precise specifications.
The ‘MyoMastery’ section provides users with tools to improve their myoelectric control, offering real-time monitoring of EMG sensor signals and training sessions for the AI module, thereby enhancing the responsiveness and accuracy of the prosthetic hand.
‘Developer Mode’ in the app directly tackles slight finger positioning discrepancies due to manufacturing variations in each prosthetic hand. This mode ensures precise calibration of core grips post-production, securely saving these settings to the hand’s chip and preventing end-user modifications. As a result, every Alt-Bionics prosthetic hand offers consistent, accurate performance right out of the box.
The app is an essential component of the Alt-Bionics prosthetic ecosystem, providing a user-friendly interface for personalizing the prosthetic to individual needs.
Conclusion
In our functional overview, we’ve elevated the bionic hand from its initial prototype phase to a more sophisticated and user-centric product. Our work has focused on refining the grip navigation system, creating an efficient exchange between the mobile application and the hand, and ensuring a seamless user interface for grip management.
For those interested in the technical details of this evolution, our technical blog post delves into the specific hardware and software advancements we’ve made. We cover the custom design of the printed circuit board (PCB) and the comprehensive firmware enhancements that underpin the bionic hand’s improved performance. The blog also explores our progress in integrating artificial intelligence to accurately interpret EMG patterns, enabling the bionic hand to respond more effectively to the patient’s muscle commands. Please also explore our portfolio page for this project.
At the time of writing this blog, the bionic hand is currently in the field trial stage with real patients, a critical step in ensuring its effectiveness and user-friendliness. We are actively supporting our client through this process, striving to help them achieve their goal of making advanced prosthetic technology both accessible and affordable.
