Underactuated Prosthetic Hand Achieves 90% Object Grasp Success Rate

Why It Matters

This research offers a practical solution for improving the quality of life for amputees by providing an affordable and functional prosthetic. The integration of user-specific muscle signals and a mechanically adaptive design addresses key human factors in prosthetic limb development, focusing on restoring essential grasping capabilities.

Key Finding

The study successfully created a 3D-printed prosthetic hand that uses muscle signals to control a flexible tendon system, enabling it to reliably grasp and release a variety of common objects.

Key Findings

• The developed prosthetic hand can effectively grasp and ungrasp objects of different sizes and shapes.
• The underactuated finger mechanism, controlled by EMG signals, allows for dynamic responses based on user muscle flex and strength.
• The design is cost-effective, making it a practical solution for amputees.

Research Evidence

Aim: To develop and evaluate a cost-effective prosthetic hand with an underactuated finger mechanism and EMG control for effective object grasping and release.

Method: Prototyping and Experimental Testing

Procedure: Existing prosthetic hands were reviewed for cost-effectiveness. A prosthetic hand was designed using SolidWorks and 3D printing, featuring an underactuated finger mechanism with a tendon system connected to a servo motor. EMG sensors were used for control. The hand's grasping and ungrasping capabilities were tested with various objects (pliers, screwdriver, phone).

Context: Prosthetics and Assistive Technology

Design Principle

Adaptive bio-mechanical systems enhance user interaction and functional restoration in assistive devices.

How to Apply

When designing assistive devices, consider integrating bio-signal input and flexible mechanical linkages to allow for a more natural and responsive user experience.

Limitations

The study does not detail long-term durability, user comfort over extended periods, or the range of fine motor skills achievable. The effectiveness may vary significantly with individual muscle signal strength and control proficiency.

Student Guide (IB Design Technology)

Simple Explanation: This research shows how a cheaper, 3D-printed hand can be made to work well for people missing a hand by using muscle signals to control its grip.

Why This Matters: This research is relevant because it demonstrates how to create affordable, functional assistive technology that directly improves a user's ability to interact with their environment, addressing a significant human factor need.

Critical Thinking: How might the long-term psychological impact of using a functional, yet potentially less aesthetically refined, prosthetic hand compare to a more cosmetic but less functional one?

IA-Ready Paragraph: The development of a cost-effective prosthetic hand, as demonstrated by Sujana et al. (2023), highlights the potential of underactuated mechanisms and bio-signal control (EMG) to restore grasping functionality for amputees. Their research, which utilized 3D printing for fabrication and tested the device with various objects, achieved notable success in grasping and releasing diverse items, underscoring the importance of adaptive mechanical design and intuitive user interfaces in assistive technology.

Project Tips

• Focus on a specific functional deficit that can be addressed with a prosthetic or assistive device.
• Consider using readily available sensors and fabrication methods to keep costs down.
• Clearly define the user's needs and how the design directly addresses them.

How to Use in IA

• Use this study to justify the need for a functional prosthetic or assistive device in your design project.
• Reference the use of EMG sensors and underactuated mechanisms as potential design strategies.
• Cite the cost-effectiveness aspect to support the development of accessible solutions.

Examiner Tips

• Ensure your design process clearly links user needs (human factors) to specific design choices.
• Demonstrate how your chosen control system (e.g., sensors, actuators) directly enhances the device's functionality for the user.
• Justify the material and manufacturing choices based on cost-effectiveness and performance.

Independent Variable: Prosthetic hand design (underactuated mechanism, tendon system, EMG control)

Dependent Variable: Object grasp success rate, effectiveness of grasping and ungrasping

Controlled Variables: Types of objects used for testing, environmental conditions, user's muscle flex and strength

Strengths

• Addresses a significant real-world need for affordable assistive technology.
• Demonstrates a practical implementation of underactuation and EMG control.
• Utilizes accessible manufacturing methods like 3D printing.

Critical Questions

• What are the ethical considerations of providing a functional but potentially less aesthetically pleasing prosthetic?
• How can the user's proprioceptive feedback be simulated or enhanced with this type of prosthetic?
• What are the potential failure modes of the tendon system under prolonged or strenuous use?

Extended Essay Application

• Investigate the biomechanics of human hand grasping and how to replicate specific aspects using underactuated mechanisms.
• Explore advanced EMG signal processing techniques for more nuanced control of prosthetic limbs.
• Conduct a comparative analysis of different low-cost fabrication methods for complex prosthetic components.

Source

Cost-Effective Prosthetic Hand for Amputees: Challenges and Practical Implementation · International Journal of Integrated Engineering · 2023 · 10.30880/ijie.2023.15.07.025