Fairfield University: School of EngineeringDepartment of Mechanical Engineering

EG 390-391 – Senior Design Project

Prosthetic Hand Multi-tool Attachment

Prepared by:Christopher Babcock (ME)

Thomas Daniello (ME)Thomas Lukacovic (ME)

Michael Nagy (ME)

Faculty Advisor:Professor James Cavallo

May 6, 2016

Abstract

Professor James Cavallo owns a pizza shop, and saw a man with a prosthetic arm struggle to eat a piece of pizza. He saw a need for an improvement or modification to the prosthetic for more versatile tools. Every day, amputees struggle to perform the basic tasks that we take for granted. The goal of this project is to provide maximum everyday functionality with minimum interference and bulk. Our objective is to create an attachment to an existing prosthetic with multiple interchangeable tools that will help the amputee perform everyday tasks with less hassle.

The initial design was presented to the amputee, who provided valuable feedback on the needed design changes. Through many Computer Aided Drafting (CAD) models, and 3D printed models, we were able to formulate a design that achieved all of our goals, and fit into all our constraints. Throughout the course of the spring semester, we will be able to complete the manufacturing design of our product, and begin the actual manufacturing and assembly of our product. By the end of the year, we will have a fully marketable piece of equipment that we will be able to use to gather a client base, and sell our product.

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Table of Contents

Abstract............................................................................................................................................2

Introduction......................................................................................................................................5

Objectives........................................................................................................................................6

Design Constraints...................................................................................................................................6

Engineering Standards.............................................................................................................................7

Review of Literature........................................................................................................................7

Concept Analysis...........................................................................................................................11

Design Discussion.........................................................................................................................12

FMEA Analysis.............................................................................................................................18

Manufacturing, Fabrication, Assembly, and Instrumentation.......................................................19

Testing...........................................................................................................................................21

Test Results & Discussion.............................................................................................................22

List of Courses Supported.............................................................................................................22

Schedule.........................................................................................................................................23

Recommended Future Work..........................................................................................................24

Business Plan / Industry Market Analysis / Economic Analysis...................................................24

Quad Chart.....................................................................................................................................25

Conclusion.....................................................................................................................................26

References......................................................................................................................................27

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Table of Figures

Figure 1 - User Feedback on Initial Design.....................................................................................5Figure 2 - User Feedback on Initial Design.....................................................................................6Figure 3 - DEKA Arm.....................................................................................................................7Figure 4 - Anthropomorphic Hand..................................................................................................8Figure 5 - Guanglin Design.............................................................................................................8Figure 6 - New Prosthetic Hand......................................................................................................9Figure 7 - Bengtson Prosthetic........................................................................................................9Figure 8 - Still Prosthetic Attachment.............................................................................................9Figure 9 - Lux Prosthetic Attachment...........................................................................................10Figure 10 - Ball Prosthetic Hand...................................................................................................10Figure 11 - Decision Matrix..........................................................................................................11Figure 12 - Initial Design...............................................................................................................12Figure 13 - Initial Design...............................................................................................................12Figure 14 - Rev 1.0 Design Shorten 3/4".......................................................................................13Figure 15 - Design Widen 1/4"......................................................................................................13Figure 16 - Rev 1.0........................................................................................................................14Figure 17 - Rev 1.1 Fork Revisions...............................................................................................15Figure 18 - Rev 1.1 Notch cut out for flashlight deployment tab..................................................15Figure 19 - Rev 1.1 Model.............................................................................................................16Figure 20 - Tool Locking Notch....................................................................................................16Figure 21 - Updated Carabiner with Locking Mechanism............................................................17Figure 22 - Final Tool Design.......................................................................................................17Figure 23 - FMEA Analysis..........................................................................................................18Figure 24 - Risk Cube....................................................................................................................19Figure 25 - Pocket Knife Assembly Concept................................................................................19Figure 26 - Bike Tool Assembly Concept.....................................................................................20Figure 27 - Flashlight Holder Drawing for Manufacturing...........................................................20Figure 28 - Stylus Drawing for Manufacturing.............................................................................21Figure 29 - Schedule......................................................................................................................23Figure 30 - Quad Chart..................................................................................................................25

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Introduction

Our faculty advisor, Professor James Cavallo, owns a pizza shop in Connecticut. He was at his restaurant one day, and a man with a prosthetic hand came in to eat. Professor Cavallo watched as this man struggled to use his hook to effectively eat his pizza. This man tried many different approaches, and there was no way that was easy for him to do.

There are things that we take for granted every day that that people who have hooks for hands are not capable of. Simple actions like using a fork and a knife, opening a door, carrying in bags from the car, or scrolling through pictures on our cell phones. We set out to solve this problem, by providing some sort of a tool that will aid the amputee in performing some basic tasks made difficult by their handicap.

An initial iteration of our design was completed by a group before us. These people presented the initial 3D printed model to the gentleman in the pizza, and he was able to provide valuable feedback into the design. From there, we were able take the design, and progress it further. The gentleman can be seen using the initial design in Figures 1 and 2.

Figure 1 - User Feedback on Initial Design

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Figure 2 - User Feedback on Initial Design

Objectives

Design ConstraintsWe strove to create a tool that the amputee could use to accomplish his tasks, with little

to no change to the equipment he currently has. We wanted something lightweight and durable that would be universal adaptable to all prosthetic hands with a hook attachment. Optimally, the amputee would be able to attach it, clean it, and care for it with the use of only one hand. The amputee should be able to wear the device 24/7, to allow him access to his tools at any moment. Since the cost of the device will be high, it should have a life expectancy of at least 10 years, enabling the user to get plenty of time out of it. If the device should break, though unlikely, it should be repairable, so that the user does not have to buy an entirely new device.

Our design constraints are considered below:

Less than 2 pounds Self-contained Washable Life expectancy 10yrs Repairable Ease of use with one hand Durable – withstand daily use Fits onto any prosthetic arm Under $2000 per unit

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As we develop the design, we hope to bring the cost down significantly. But it is important to understand that this is a medical device, and depending on the materials and process we use to build these devices, the cost will be significant. The tool will likely not be mass produced, also increasing the unit cost.

Engineering StandardsAs there is little to no precedence for what we are trying to make, there is minimal

standard data readily available for us to use. However, we are attempting to pursue many avenues. Since this is a medical device, there are many ADA standards that we could potentially fall under. There have been numerous ergonomic studies done lately on the best way that various tools should conform to a person’s body. Since we are planning on eating with this device, there are material standards for the sanitation of forks, knives, and other utensils. This is especially true for collapsible silverware, often used in applications like camping. Since the tools of this device will fold, there must be standards regarding the locking mechanisms, and how to best fold the devices, and lock them in various positions. All of these standards are a work in progress, and we have feelers out in various directions trying to collect data.

Review of Literature

There is little literature available on the type of device that we are proposing. Most research efforts involving prosthetic hands and attachments has gone into technology advanced total hand replacements, offering the amputee a near perfect replacement to his hand. Nevertheless, there have been some previous patent applications for devices along the same grounds as ours, with some significant differences.

In 2014, the Department of Veterans Affairs studied to optimize the DEKA Arm (named after its founder Dean Karmen), and provided feedback for optimization of the gen 2 (second-generation) prototype and evaluation of the gen 3 (third-generation) prototype. [1] The DEKA

Arm (seen in Figure 3) is a brain powered smart arm, linking directly to the user’s brain to control hand movement. This article summarizes recommendations to improve gen 2 and reports satisfaction and usability ratings of gen 2 and gen 3. Data were collected from 39 subjects; 37 subjects were included in this analysis. Usability and satisfaction were evaluated using the Trinity Amputation and Prosthesis Experience Scale (TAPES) and study-specific usability and satisfaction

scales. Descriptive statistics were examined and prototypes compared using Wilcoxon rank-sum. Results were stratified by configuration level and outcomes compared by prototype. Overall,

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Figure 3 - DEKA Arm

TAPES scores were similar; however, scores of the TAPES aesthetic satisfaction subscale were higher for gen 3. Compared with gen 2 users, gen 3 users were more satisfied with appearance, grips, and doffing and rated overall usability higher.

In 2008, Andrianesis et al presents the mechanical design of an ultra-lightweight, biometrically actuated anthropomorphic hand for prosthetic purposes [2]. The proposed design (seen in Figure 4) is based on an underactuated configuration of 16 joints and 7 active degrees of freedom. Shape Memory Alloy wires are used as motive elements of a specially designed actuation system installed within the envelope of the hand and forearm; due to their inherent contraction ability when heated, these innovative micro-actuators produce linear motion which is imparted to the fingers via a tendon transmission system. The overall design is completed with the integration of the necessary locking mechanisms for power saving. An experimental prototype of the suggested prosthesis has been fabricated using rapid prototyping techniques and it will be used as an evaluation platform for further research towards the development of a truly multifunctional, silent and cosmetically appealing hand for upper limb amputees.

In 2008, Guanglin et al proposed a new approach to improve the control of prosthetic arm rotation in amputees [3]. Arm rotation is sensed by implanting a small permanent magnet into the distal end of the residual bone, which produces a magnetic field (seen in Figure 5). The position of the bone rotation can be derived from magnetic field distribution detected with magnetic sensors on the arm surface, and then conveyed to the prosthesis controller to manipulate the rotation of the

prosthesis. Proprioception remains intact for residual limb skeletal structures; thus, this control system should be natural and easy-to-use. In this study, simulations have been conducted in an upper arm model to assess the feasibility and performance of sensing the voluntary rotation of residual humerus with an implanted magnet. A sensitivity analysis of the magnet size and arm size was presented. The influence of relative position of the magnet to the magnetic sensors, orientation of the magnet relative to the limb axis, and displacement of the magnetic sensors on the magnetic field was evaluated. The performance of shielding external magnetostatic interference was also investigated. The simulation results suggest that the direction and angle of rotation of residual humerus could be obtained by decoding the magnetic field signals with magnetic sensors built into a prosthetic socket. This pilot study provides important guidelines for

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Figure 4 - Anthropomorphic Hand

Figure 5 - Guanglin Design

developing a practical interface between the residual bone rotation and the prosthesis for control of prosthetic rotation.

In 1998, Doshi et al has a discussion about the prosthetic arms that were currently available at the time [4]. Current prosthetic hands, although functional, have the potential of being improved significantly. We report here the design and development of a novel prosthetic hand that is lighter in weight, less expensive, and more functional than current hands. The new prosthesis features an endoskeleton embedded in self-skinning foam that provides a realistic look and feel and obviates the need for a separate cosmetic glove (seen in Figure 6). The voluntary-closing mechanism offers variable grip strength. Placement of joints at three locations (metacarpophalangeal and proximal and distal interphalangeal) within each of four fingers affords realistic finger movement. High-strength synthetic cable attached to the distal phalanx of each finger is used to affect flexion. A multiposition passive thumb provides both precision and power grips. The new prosthesis can securely grasp objects with various shapes and sizes. Compared to current hands, weight has been reduced by approximately 50%, and cable excursion required for full finger flexion by more than 50%. The new endoskeletal prosthesis requires approximately 12-24% less force input to grasp a variety of everyday objects, largely due to its adaptive grip. Production cost estimates reveal the new prosthesis to be significantly less expensive than current prosthetic hands.

In 1974, C. Bengtson was granted a patent for a tool holding prosthetic device including a connector for attachment to an artificial body member and a tool or set of tools wherein the connector and tools are provided with snap-fit connecting means [5]. This device removes the original hook, and installs a socket-like connector device in its place to attach the various tools, seen in Figure 1. Many different specialized tools are created to attach to the base, and are not operational with any other device.

In 1995, Still et al was granted a patent for a terminal device which is attachable to the end of a prosthesis on an arm and there serves as an attachment site for a variety of tools or implements designed to mate with the terminal device [6]. The terminal device (seen in Figure 8) comprises a first main part in operable and pivotal combination with a second main part, the combined main parts providing on one end a device for attaching to the end of an arm prosthesis, and on the other a device for attaching a variety of implements, the said device for implement

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Figure 6 - New Prosthetic Hand

Figure 7 - Bengtson Prosthetic

Figure 8 - Still Prosthetic Attachment

attachment providing articulation capabilities that allow positioning of the implements in a variety of positions relative to the position of the arm prosthesis. Among the implements which can be attached are for example: cutting tools (such as saws, files, knives, scrapers, and awls); various wrenches (such as open end wrenches, closed end wrenches, ratchet wrenches, adjustable wrenches, Allen wrenches, and pipe wrenches); and a variety of other implements such as spoons, scoops, spatulas, planes, brushes, fishing rods, and stirring devices. This device is capable of handling a wider variety of standard tools, as well as those tools designed specifically for mating with this device.

In 1951, Michael Lux was granted a patent for an invention relating to an attachment for an artificial arm and, in particular, to a manipulator adapted to permit the use of a hand tool or implement such as a rake, broom, pitchfork or the like, having a handle [7] (seen in Figure 9). Known artificial-arm attachments necessitate excessive arm or body movements in the performance of simple tasks, such as manipulating hand tools or implements. It is accordingly the primary object of his invention to permit nearly normal use of simple hand tools by a wearer of an artificial arm, without undue effort. This design aids a user in any tool that has a handle on it, for use during standard yard work.

In 2008, Robert Erb was granted a patent for a realistic looking hand prosthesis made preferably of an

elastomeric material is formed to hold a substantially spherical ball [8]. The ball is held in the hand securely by friction between a ball and a handmade of a rubber like material wherein the ball is slightly larger in diameter than the conformed hand. The ball may be selectively rotationally oriented in three orthogonal directions of angular freedom. The ball is provided with various attachment means for attaching implements, which attachment means may include holes of various shapes and sizes, holes with projections, magnetic attaching means and threaded or other fastening means (seen in Figure 10). Providing of angular adjustment in three orthogonal directions enables the ball to be able to attach a large number of useable implements to be positioned so as to aim the axis of each implement as needed and to rotate about its axis. The ball may be utilized in connection with a natural or prosthetic hand.

Concept Analysis

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Figure 9 - Lux Prosthetic Attachment

Figure 10 - Ball Prosthetic Hand

We implemented a design matrix to aid us in concept design. We were looking to design something small and self-contained that would not require massive amounts of assembly. We wanted a universal design that would attach onto all prosthetic arms, with little to no modification. We wanted to create a device that would position the tools so they were in a natural, ergonomically correct position. And we wanted to minimize interference with the hook of the installed prosthesis.

We generated three designs that would accomplish the tasks at hand. The first was a design similar to the designs seen in the literature review that would involve unscrewing the main hook and screwing in some sort of an attachment with multiple fold-out tools. The second design is a cuff design, where the user would attach this cuff above the hook, underneath the wire for the main hook. This cuff would rotate, allowing the user to select the desired tool, and its angle, and then lock it in place with a set screw. The third design is a Swiss-Army like design, where the user would attach a small unit to the inside of his arm. The various tools would fold out, and lock in the necessary working position. The decision matrix can be seen in Figure 11.

Hook replacement

Cuff Design

Swiss Army Knife Design

Interface with Hook 30% 0 8 9Ease of Use 15% 3 7 7Simplicity 10% 6 6 7Cost 5% 3 5 6Customization 2% 2 4 4Universality 10% 8 8 8Durability 10% 7 7 7Washable 3% 6 4 6Weight 10% 4 6 8Ease of Installation 5% 2 5 8

3.42 6.85 7.71

Figure 11 - Decision Matrix

Our decision matrix shows that the Swiss-Army knife design comes out just slightly ahead of the cuff design, a conclusion that the group who worked on the project ahead of us has. They had previously done one iteration of a design, and we picked up where they left off. Their design can be seen in Figures 12 and 13.

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Figure 12 - Initial Design

Figure 13 - Initial Design

Design Discussion

Upon starting this project our group was given the preexisting work done on the project which is the rev. 1.0 designs. When meeting with Professor Cavallo we were asked to make changes he had already suggested which included the shortening the overall length of the tool by ¾ of an inch and removing the taper see in Figure 14 below:

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Figure 14 - Rev 1.0 Design Shorten 3/4"

This allows for a more compact design making the tool easier to manage when attached on the prosthesis and cuts down on the overall weight of the device. In this revision of the design the tool was also made for an individual who has lost their left arm. In the same change proposal the carabiner will be moved to the other side of the device allowing for a right handed device. The overall width was also widened to accommodate a wider fork attachment and the strap slots were moved apart to gain better support when strapped to the prosthetic arm.

Figure 15 - Design Widen 1/4"

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Slot moved to the end of device

Figure 16 - Rev 1.0

Other structural improvements were later made to strengthen these strap slots ensuring that our prototype did not break when strapped to a prosthetic arm. This was done by adding material at the seams and making sure there were no weak 90 degree joints. Once the base was adapted for a right handed user the tools got most of the design attention. The original carabiner was reduced in size to accommodate for the reduction of space on the side of the device. It was determined through crude physical testing that it would not support the general weight of several grocery bags. This test was done in a weekly meeting by hanging a variety of weighted bags from the carabiner and observing the flexion and bending. To increase the holding capability of the carabiner the size was increased and material was added in thinner areas. In the future, before machining any parts ANSYS will be run on parts such as these to determine how much weight the carabiner can be rated for. To accommodate for the larger carabiner a slot was cut into the base so the carabiner can fit under the other tools in the device.

The usability of the main tools was then looked at. It was determined that there needed to be a tab somewhere on the tool that made it easier for the tools to be operated with one hand. This problem was solved by adding a tab on the rotating base of each tool allowing deployment with one hand easily. For the time being the tools are all placed at 130 degrees when deployed until an ergonomic standard can be found giving the optimal angle; for an eating utensil in the case of the fork, and for operating a stylus in the case of the phone stylus. The fork was then redesigned to look more like normal household fork. This was done by adding a fourth prong and elongating each to a point. A curve was then added to hold food better as a regular fork is intended to do.

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Carabiner moved from left to right

Figure 17 - Rev 1.1 Fork Revisions

It was at this point that we analyzed the usefulness of each tool that was originally on the device; fork, phone stylus, and wrench. While both the fork and the phone stylus received positive feedback from the amputee we have been in contact with, the wrench seemed to require too much rotational motion to be useful. We proposed that a flashlight be installed in place of the wrench. Was developed to hold an off the shelf flashlight operated by twisting the top of the flashlight. To maximize the usefulness of the flashlight it was under general agreement in the group that it should be at 180 degrees rather than the 130 degrees of the other tools. Because the flashlight is something that would be locked into place rather than used to interact with other things it would need to point straight ahead. A notch was then cut into the front of the device because of interference with the deployment tab.

Figure 18 - Rev 1.1 Notch cut out for flashlight deployment tab

This iteration without the flashlight is seen in Figure 19.

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Deployment TabsElongated Curved prongs

Notch cut for Flashlight

Figure 19 - Rev 1.1 Model

We needed to create some way to lock the tools into their appropriate place. As the users were using the device, the tools were moving all over the place. A locking device was proposed similar to that on a bike tool. A friction based lock would provide us with easy installation and development. A piece of aluminum was bent and mounted to the bottom of the body. Each tool as notched appropriately that would allow the tool to lock into place when it reached the correct location, but with the force of only one hand, could be put back into place as needed. The new tool with the locking notch can be seen in Figure 20:

Figure 20 - Tool Locking Notch

A new design of the carabiner was required. The existing holder was just an open holder, and we wanted something that could close so as to more safely carry the required bags. The carabiner was designed so that it was a little longer, and had a threaded lock on the outside so that it could be secured closed, with only one hand. The new carabiner can be seen in Figure 21:

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Notch For Locking Mechanism

Figure 21 - Updated Carabiner with Locking Mechanism

Feedback suggested that it would be beneficial to make a cleaner smoother model that was sleeker and easier to clean. The whole casing redesigned so that the carabiner hook could be more easily converted from left to right. The body was made smoother and rounder, so that it was a little slimmer, and would more comfortably fit under clothing. The back of the body was kept open so that less dirt and debris would get caught in the tool, and it would be easier to clean. A final iteration of the tool can be seen in Figure 22:

Figure 22 - Final Tool Design

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FMEA Analysis

We performed a standard Failure Modes and Effect Analysis (FMEA) on our part. We tried to incorporate as many problems as we could see feasibly happening. We took the breaking of all of the various parts of the assembly into consideration, as well as the battery of the flashlight dying. The most obscure problem that we input was a breaking of the human arm, either from total misuse of the tool, or sheer bad luck. Our FMEA analysis can be seen in Figure 23:

Figure 23 - FMEA Analysis

An over stress of any of the individual tools would cause it to break, rendering the tool useless. In each of these cases, the tool would need to be replaced. If the straps for the device break, they need to be individually replaced. These occurrences are reasonably out of our control. We can design the tools using stronger materials, but beyond that, it is the responsibility of the user to not overload the tool. The flashlight battery dying is an inevitable occurrence, and should be able to be replaced by the user with one hand. The user’s arm breaking is completely out of our control. If the user does something so completely wrong that they end up breaking their arm, there are no design changes that we can do to avoid that.

This analysis is summed up in our risk cube, seen in Figure 24.

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Figure 24 - Risk Cube

All of our risk issues lay well within the green portion of the risk cube. The only one in the yellow is item e, arm breaking. As we stated above, this item is well outside our control, and of little concern to us at this time.

Manufacturing, Fabrication, Assembly, and Instrumentation

There were a few different manufacturing methods that we considered while doing our analysis. The first consideration was to assemble the device like a pocket knife, where the tool would be built in layers. Each tool would be manufactured or stamped from a sheet, and each lock would also be flat. Then all of the layers would simply be fastened together, with a plastic outer layer for aesthetics (see Figure 25 for concept drawing).

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Figure 25 - Pocket Knife Assembly Concept

We ended up going with a design more akin to the bike tool that was mentioned in the design discussion for the locking mechanism. This device would have a plastic molded base with the locking mechanism secured to it. Each tool would be individually machined or pressed with locking notches and deployment tabs depending on the feasibly. The tools were all fastened together with a through bolt, which could be undone with only one hand and a Philips screw driver if needed. This would allow the tools to be swapped out, replaced, cleaned, etc. greatly

increasing the usable and versatility of the device (see Figure 26 for concept).

In an effort to eventually send our tools out for manufacturing, we were able to generate drawings of the models. The drawings for the tools were not fully completed, as they do not have Geometric Dimensioning & Tolerancing in them, however they gave us an idea of what we had to do to continue our work. These drawings can be seen in Figure 27 and 28:

Figure 27 - Flashlight Holder Drawing for Manufacturing

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Figure 26 - Bike Tool Assembly Concept

Figure 28 - Stylus Drawing for Manufacturing

Testing

Our testing was limited to user feedback and analysis by various amputees. Their feedback was vital our design changes made throughout the duration of the project. We provided out device to 4 different users, and asked them to wear it for a few hours while they performed daily tasks. We asked them to not worry about stressing the tool, as that would indicate to us where the weak spots were, and what we needed to modify and strengthen in our final revision.

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Test Results & Discussion

Our users provided us with valuable information to improve and renew our device. Some of the feedbacks provided were:

Tools do not lock into position, makes use difficult Body is square and bulky, might want to make it sleeker and smoother Dirt and grime gets caught in the body often, try to make easier to clean Screwdriver tool is not feasible Device breaks at the strap holders, reinforce there Bags fall out of bag holder if too many Tools are hard to deploy

Based on this feedback, we were able to shape our design focus, and make the correct changes based on what the users wanted to see. Unfortunately food consumption was limited due to the 3D printed plastic, but we were still able to generate some feedback from them. Not being amputees ourselves, it was extremely difficult to try to understand the use from their perspective. Even using the tool on our arms, if was out nature to cheat and use our hands anyways. This is intended to be a user based tool, and that is what the feedback allowed us to focus on.

List of Courses Supported

The following courses supported our efforts in this course:

EG 211 – Engineering Graphics I EG 212 – Engineering Graphics II ME 318 – Finite Element Analysis EG 390 – Senior Design Project I EG 391 – Senior Design Project II ME 322 – Advanced Dynamics

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Schedule

Our working schedule is shown in Figure 29.

Win

ter B

reak

User Validation

Design for Manufacturing

Analysis

Fabrication & Assembly

March AprilFall Semester Spring Semester

Design Constraints

Literature Review

Concept Generation

CAD Design and Analysis

September October November December January February

Design Freeze

Final Report

Figure 29 - Schedule

During the month of September, we looked at our design and established our design constraints for this project. During that phase, we started a literature review to get an idea of what other people had already done in this area, and what products, if any, were already on the market. This rolled directly into a concept generation, where the team got together and established the three concepts that we discussed earlier. After narrowing down the concepts, we jumped into CAD design and analysis, and refined our work. We used the 3D printer to print a few hard versions of our designs, and are continuing to analyze them.

After winter break, we put our model in the hands of a few amputees, and got user feedback on our design. Alongside this, we started work on our design for manufacturing, looking at material selection, and fabrication methods. We were unable to truly freeze our design, as we kept receiving user feedback up through April. We were however able to modify and condense our last month to produce a fully functioning 3D Printed prototype.

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Recommended Future Work

We were able to generate a working 3D model, and put it in the hands of many different amputees. This provides a solid foundation for future groups to continue our work where we left off. There are some things that need to be done to make this design more successful. We would like to see actual metal manufactured tools into a fully manufactured prototype, so that this design could potentially start looking at retailers. We would also begin to pursue a second generation of our design, which would be the cuff design, better integrating the hook. The score in our design matrix was not that much lower than the current pocket knife design, and we believe that it has a lot of room to offer us with increasing number, type, and size of tools.

A lot of the feedback also suggested that we should look into generating different interchangeable tools, so that as the tool would be more customizable to the user. Depending on the age, gender, or activity, different people would want the tool to perform different functions. By creating a wider toolset, it would make the device more useful, and open to more consumers.

Business Plan / Industry Market Analysis / Economic Analysis

What Industry does out product belong to, and who are the competitors?

When searching for companies who sell/ make prosthetic attachments our product belongs to the “Medical, Dental, and Hospital Equipment and Supplies Merchant Wholesalers' industry”. The overall market value of the 'Medical, Dental, and Hospital Equipment and Supplies Merchant Wholesalers' industry has grown from 5.9% in 1989 to 7.2% in 2011 in the last 23 years. The growth of 1.3% is low due to the highly price competitive market. There is no specific number of companies in this field. The main companies in the field are Texas Assistive Devices, DEKA Research and Development Corporation and Next Step Orthotics & Prosthetics Inc. One specific company called “Texas Assistive Devices” makes a similar product, but ours has the ability to be operated using just one hand, is light weight, straps directly to the prosthetic arm, and replacement parts will be sold at a reasonable price.

Is there anything currently on the marker that is like our product?

After some research, it is noticed that the market is somewhat lacking when it comes to products like ours. The only product on the market currently is the N-Abler which could be useful for some amputees. Once our product becomes available on the market it will beat the competition because of it specifics like weight, cost, longevity, durability and reliability.

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Who are the people that will buy our product?

As of 2005 there are nearly 2 million people living with limb loss in the United States. There are approximately 185,000 amputations that occur in the US each year. The Amputee Coalition has statistics that show that of those people, 9.7% of people have upper limb loss and 90.3% have lower limb loss. 89.2% of amputees indicated that they have a prosthetic and wear it regularly. This device would be readily available to any of these over 150,000 people, allowing them to perform daily tasks with ease without losing function of their existing prosthetic.

Quad Chart

A simple quad chart for our project can be seen in Figure 30:

Figure 30 - Quad Chart

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Conclusion

We were given the task of generating a device that would aid amputees with a prosthetic hook to do daily tasks. We created a design that attaches to the inside of the forearm of the prosthetic arm, and has various fold out tools, such as a fork, a flashlight, a bag carrier, and a stylus. This device will aid the amputee in his daily tasks, without hindering his motion or being awkward. Throughout many design changes, and significant user validation, we have achieved a functioning printed prototype. Through manufacturing analysis and drawings, we have set the path in motion for the continuation of our project.

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References1. Resnik, Linda,P.T., PhD. and M. Borgia A.M. User ratings of prosthetic usability and

satisfaction in VA study to optimize DEKA arm. Journal of Rehabilitation Research and Development 51(1), pp. 15-26. 2014.

2. Andrianesis, K.; Tzes, A., "Design of an anthropomorphic prosthetic hand driven by Shape Memory Alloy actuators," in Biomedical Robotics and Biomechatronics, 2008. BioRob 2008. 2nd IEEE RAS & EMBS International Conference on , vol., no., pp.517-522, 19-22 Oct. 2008

3. Guanglin Li; Kuiken, T.A., "Modeling of Prosthetic Limb Rotation Control by Sensing Rotation of Residual Arm Bone," in Biomedical Engineering, IEEE Transactions on , vol.55, no.9, pp.2134-2142, Sept. 2008

4. Doshi, Rajiv; Yeh, Clement; LeBlanc, Maurice; “The design and development of a gloveless endoskeletal prosthetic hand” in Journal of Rehabilitation Research and Development Vol. 35 No. 4, pp. 388-395, Oct. 1998

5. R. Tool Holding Prosthetic Device. C. Bengtson, assignee. Patent US3802302A. 9 Apr. 1974. Print.

6. Attachment for Artificial Arm Prosthetic Device. Ronald H. Farquharson, Danny P. Still, assignee. Patent US5464444A. 7 Nov. 1995. Print.

7. Tool-Manipulator Attachment for Artificial Arms. Michael Lux, assignee. Patent US2561523A. 24 Jul. 1951. Print.

8. Ball Hand Prosthesis. Robert A. Erb, assignee. Patent US7438726B2. 21 Oct. 2008. Print.

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