One Wing Angels

 Design Review July 9th:

Our focus is developing an adaptable wing prosthetic for a parrot as part of a broader animal prosthetic initiative. We are currently designing a wing prosthetic specifically for a parrot, but the design can easily be scaled to accommodate any size of bird. Ultimately, the core mechanics remain the same regardless of the dimensions.

The prosthetic works by coupling the damaged wing to the functioning one using a diamond mechanism, allowing them to flap in tandem. As David mentioned, our subgroup is dedicated to rehabilitating parrots with damaged wings. We accomplish this by attaching a prosthetic to the injured wing and linking it to the functioning one. When the bird flaps its healthy wing, the damaged wing is pulled up and down simultaneously, mimicking a natural flapping motion. Our teammate Julia created 3D animations to illustrate this concept, though we unfortunately cannot show them right now. To facilitate this synchronized movement, Ariella proposed using a diamond mechanism, which we have brought as a physical prototype.

The diamond mechanism resolves early issues with motion symmetry by ensuring both wings elevate simultaneously. Initially, we faced a symmetry problem when trying to attach strings directly to the wing joints; if one wing went up, it loosened the string and caused the other to drop. Because we need both wings to move together, we designed the diamond mechanism to sit on the bird's back. When the functioning wing rises, it pulls a string that stretches one side of the diamond. This stretching motion simultaneously pulls the string attached to the injured wing, forcing it to rise as well.

Our primary goal is to achieve symmetrical movement. This mechanism ensures that both wings move in harmony.

By transferring the physical effort to the healthy wing, the prosthetic allows the fractured wing to rest and heal. The injured wing does not have to exert any force. The functioning wing drives the motion, passively carrying the damaged wing through the flapping cycle.

The design also factors in the bird's natural, forward-moving flight mechanics. We are planning our 3D printing approach around the specific directional movements that the animal is capable of making.

[Interrupting] I apologize, the window is open.

We intend to use screws instead of tape or glue to ensure structural rigidity. This approach makes the assembly much firmer. The screws will integrate directly into the components and sit flush, providing a highly secure hold.

To mount the moving diamond mechanism securely to the bird, we are integrating a track system. As David noted, combining the diamond with a track smooths out the motion. I am currently modeling the bird's main body, or fuselage, to figure out how the diamond will sit on its back during flight. Since all the joints on the diamond move, there is no stationary point to safely attach it directly to the bird. The track solves this issue by allowing the diamond to expand and contract freely while providing fixed mounting points to secure the entire assembly to the bird.

We must manufacture multiple independent pieces for each section of the wing to allow for varied, non-rigid movement. A single fixed motion for ascending or descending is insufficient, as flight requires a complex range of dynamic movements.

This ensures flexibility across the wings.

To attach the track and diamond mechanism safely, we will sew them onto a custom fabric vest worn by the bird. Laying this vest over the bird provides a secure base to mount the hardware, ensuring that no components fall off during movement.

The bird will wear a specialized vest. We are planning to make a small, pink fabric vest for the bird.

This tiny vest guarantees that all mechanical parts remain securely attached. It will be compact and highly secure.

Similar lightweight bird vests already exist on the market, proving they do not disturb the animal. You can find them on sites like Amazon, which reassures us that a lightweight fabric harness is comfortable for birds.

What is the current state of prosthetic technology for birds? Are there existing functional models for wings?

Are there any designed specifically for wings?

Existing bird prosthetics primarily focus on legs rather than wings. We researched the current technology and found that because wings are so delicate, developing prosthetics for them is incredibly difficult. From what we have seen, the few existing wing-related devices act more like protective armor than functional prosthetics.

Our project specifically targets bone injuries, filling a gap in current avian care. While researching, I found prosthetics designed to replace damaged feathers, but there is virtually nothing available to support and protect a bird recovering from a bone fracture.

Is the primary purpose to assist a bird in flying while a fractured wing heals, rather than replacing an amputated wing? I want to clarify if this is a rehabilitative tool meant to be used during the healing process.

The device serves a dual purpose: providing a 3D-printed physical replacement for a missing wing, or acting as a mechanical assist for a broken wing. If the wing is completely missing, it acts as a structural substitute. If the wing is simply broken, the mechanical component enables it to flap safely.

Does the damaged wing actively participate in the movement, or does it rest while the mechanism does the work? If one wing is damaged and the other is functioning, how does the attachment interact with the injured side?

The damaged wing will be moved by the mechanism without requiring the bird to exert its own muscles. It will not simply sit idle. The idea is that by relieving the bird from actively working the injured wing, it has a better chance of healing while still retaining the physical ability to fly.

In typical fracture recovery, such as with a human arm or leg, the standard medical advice is to keep the limb completely immobilized. Moving an injured bone generally hinders the healing process.

That realization suggests it might actually be better to build a fully independent "third wing." This mechanical substitute would perform the flapping motion while keeping the fractured wing securely immobilized.

You must consult avian veterinarians or bird rehabilitators to validate the medical appropriateness of moving an injured wing. I strongly recommend calling as many avian vets as possible. I also know a couple who breeds pigeons, and I can try to put you in touch with them. We need to verify whether moving a broken wing, even passively, is beneficial or harmful to the healing process. Furthermore, if you implement a "third wing" concept, consider the difficulty of training a bird to fly using only one biological wing and one mechanical surrogate. We must solidify the core purpose of this project: is it an active cast that assists healing, or is it a permanent mobility aid for birds with irreversible wing damage?

It appears we need to develop two distinct variants of the prosthetic to address different medical needs. One variant would keep the injured wing completely stationary for proper healing, while the other would serve as a functional replacement for a permanently deformed or amputated wing.

While the mechanism itself is your primary focus, defining its exact medical use case requires immediate outside research. The variants can remain conceptual for now, but you need to determine the best real-world application for this prosthetic. I will reach out to my contact who fosters pigeons, but in the meantime, you should be proactively calling veterinarians. I have absolute faith in your engineering abilities, but my main concern is ensuring this device aids healing rather than causing further harm. If research reveals that passive motion impedes fracture recovery, pivot the project's focus to aiding birds with permanently damaged bone structures or clipped wings. Ultimately, your core achievement is inventing a synchronized flapping mechanism; your next step is identifying the safest and most effective use case to prove that concept.

We need to define the exact application of our flapping mechanism.

Precisely; if medical research invalidates its use as a healing tool, you must pivot.

What alternative applications exist for this technology?

It is perfectly acceptable for the project's focus to evolve based on new research. You can simply document that your initial concept proved harmful to avian recovery, which led you to explore alternative applications for your flapping mechanism.

We could also adapt the mechanism into a unique visual or mechanical art piece.

Yes, we have other options if the primary goal fails.

Exactly, if nothing else works.

I appreciate that your team has pursued a purely mechanical solution rather than defaulting to robotics. Many students in these programs mistakenly believe they must rely heavily on robotics to succeed. Instead, you identified a clear use case and developed a robust mechanical system that can be rigorously tested. Moving forward, what technical issues are you currently facing with the prototype?

Our primary mechanical challenge is getting the mechanism to snap back to its original equilibrium after being stretched. Currently, when the prototype bends, it fails to return to its starting position upon release. We attempted to use elastics to force this retraction, but they are not performing effectively, so we must find an alternative solution.

Reducing the friction between the joints on those components might solve the retraction issue.

That makes sense, as the tight joints are currently pinching the rubber bands.

That is likely the source of the problem.

High friction within the joints is likely preventing the rubber bands from returning the system to equilibrium. In theory, if one rubber band stretched more than another, their natural elasticity would return the mechanism to a centered position. While we are not observing that in this basic prototype, excessive joint friction is the most probable cause.

Your next steps involve refining the materials and testing the underlying mechanism to determine its best use case. You have a solid mechanical foundation to test. Now, it essentially becomes a materials engineering project: discovering the optimal materials for both the bird's comfort and the mechanism's functionality.

Whether a bird can fly with a functioning prosthetic depends entirely on the aerodynamics of the species.

It also depends on the materials used.

Developing a fully flight-capable avian prosthetic is an unprecedented challenge. We need to research this extensively because, to our knowledge, no one has successfully created a prosthetic that allows a bird to sustain natural, stabilized flight.

Analyzing past failures in avian prosthetics will provide a crucial roadmap for your own design. You must investigate why previous attempts at flight-capable prosthetics failed so you can build upon those lessons. To test your prototype without a live bird, you could construct a rig where a motor drives the "functioning" wing, visually proving that your purely mechanical system successfully synchronizes the movement of the "injured" wing.

That rig would successfully demonstrate our core principle of mechanical tandem coupling.

Creating an alternative testing rig is essential since you cannot ethically test on injured birds. You could build a larger glider model to demonstrate how the mechanism responds to airflow when thrown. This forces you to define what constitutes success: is proving the mechanical synchronization enough, or is actual flight the goal? If full flight is unachievable, perhaps you focus on ensuring the mechanism allows the bird to glide safely. Since you cannot iterate designs on a live animal, proving the synchronization via a motorized rig or glider validates your core concept. You can then confidently state that with further research and funding, the design could be perfected for live flight.

We plan to use 3D printing because it is the most lightweight, cost-effective, and customizable manufacturing method available. Compared to wood or metal, 3D printing offers superior weight reduction, which is critical for flight. It also allows us to carefully regulate structural variables like the infill density to optimize durability.

To minimize weight, the final prosthetic will attach directly to the wing's leading edge using minimal, ring-like fasteners. We want to avoid using large, bulky components. Instead, we envision small fasteners—functioning similarly to zip ties, though more specialized—that loop around the leading edge or bone of the wing. Depending on how small and flexible these attachments need to be, we may or may not stick strictly to 3D printing for these specific parts.

If you do use 3D printing, you can reduce the weight significantly by adjusting the infill density.

Prototyping at wildly different scales, including human-sized models, can help you evaluate comfort and biomechanics. You should build a large-scale version to wear yourselves. Even though human anatomy differs from a bird's, experiencing how the harness pulls against your shoulders or pinches under your arms will provide valuable insight into its physical comfort. Once you refine the ergonomics on a macro level, you can scale the design back down for the bird.