P09023: Air Muscle Artificial Limb Next Generation

Project Overview

Table of Contents

image:Overall.png image:Hand Front.png image:Hand Back.png image:Prototype Front.png


Product Description/Project Objective Statement

This project is in its second generation. The overall goal is to design and build an artificial limb (arm and hand) that is capable of all of the directions of freedom of a human hand. The first generation accomplished design and building of the arm and the first three fingers. The goals for the second generation project is to add a pinky finger and thumb and optimize the system. The design and construction of the pinky finger and thumb as well as the optimization should be accomplished by the end of the winter quarter of the 2008 academic year. Wrist and arm motion is not required for this project.

Key Business Goals/Project Deliverables

The goals of the second generation air muscle artificial limb is to add a pinky and thumb with all of the degrees of freedom of a human hand as well as optimizing the control and mechanical systems. There are numerous sub-deliverables as well, and these can be seen on the objective tree.

Primary Market/Project Opportunities

This project is to be designed for research being conducted by Dr. Lamkin Kennard. The findings in this project will be applied to a scaled down model for use in microvascular surgery. There are products on the market similar to this that aid in microvascular surgery. This product plans to improve on existing designs by allowing all of the directions of freedom of a human hand.

Secondary Market/Project Opportunities

The most likely secondary market is prosthetics. Findings in this project could lead to advancements in that field.

This product can also act as a device to entice future engineering students. Tour groups could be taken into the bioengineering lab and prospective students could operate the hand themselves.

It is possible that this product could be used for wireless surgery. Patients could have surgery performed by a doctor thousands of miles away.

Assumptions and Constraints

Since the arm is already partially designed and built, the solutions can be implemented on the current design or the current design can be revamped. The current design also uses Labview for the human interface, so the future design will also likely use Labview.


Dr. Lamkin Kennard
Future MSD Students
Previous MSD Team
Air Muscle Suppliers
Bioengineering Field
Future Students
RIT as a whole
Future patients

Collecting Project Background Raw Data

Interview with Project Guide

First Guide Interview
Interviewer: Jim Breunig
Sponsor/Guide: Dr. Lamkin-Kennard
Date 19 March 2008, Bioengineering lab

I stated what I knew about the project thus far. I know that the project is in the second generation, and I know that it was an artificial limb controlled by air muscles.

Dr. Lamkin Kennard confirmed what I knew and stated that the limb will be scaled down in the future for use in microvascular surgery. We went into the bioengineering lab to see the project. The arm was complete, as well as the first three fingers. Dr. Lamkin-Kennard stated that the goal of the second generation of the project is to add a pinky finger and thumb. The emphasis is to be on keeping all directions of freedom of a human hand.

Dr. Lamkin Kennard emphasized that we will be needing a computer engineer and an electrical engineer as well as several mechanical engineers. She said that the project should have approximately six to eight students on the project.

I asked Dr. Lamkin Kennard why the design uses air muscles opposed to servo motors. I stated that most artificial limbs use servo motors to control the motion. She replied that since this is going to be scaled down and used in surgery, the limb must be impervious to moisture, and servo motors are generally not. Cost is also an issue, as air muscles are significantly less expensive than servo motors.

Dr. Lamkin Kennard also described how air muscles function. An air muscle consists of a flexible tube covered by a nylon or carbon fiber mesh. When pressure is applied to the inside of the tube, it can cause linear motion.

Since Dr. Lamkin Kennard answered all of my questions, I closed the interview and I said that I may be back to ask more questions in the future.

Interview with Current MSDII students

First MSD Student Interview
Interviewer: Jim Breunig
Students: Josa Hanzlik and Ellen Cretekos
Date 3 April 2008, Bioengineering lab

I contacted Jonathan, the team lead for the gen I project. He graduated last quarter and is working in Buffalo, so he will be unavailable for an interview. He directed me to Josa Hanzlik. She is the Masters student working on the project. I have sent her an e-mail, and am waiting for a reply as of 4/1/2008.

Josa Contacted me and we had an interview on April 3rd. Notes from the Interview are shown below.

The team is building their own air muscles. There is a standard operating procedure for building the air muscles and it is all documented. All of the documented data will be available to the future senior design team.

Professor Wellin assisted with the project as a liaison to the team. He procided assistance with some labview questions, as well as provide suggestions.

The hand was first rapid prototyped for a cost of approximately $50 per finger. The current team recommends rapid prototyping to avoid more costly problems once the hand is made out of steel. This is because the geometry is very complicated.

Josa and Ellen recommended that I see Dr. Doolittle about questions referring to the anatomy.

The electrical engineers on the previous team did the soldering as well as the labview programming. The mechanical engineers worked on designing the cables and air muscles.

Josa said that the controls system was one of the hardest things to design. Someone in the future Senior Design Project must have experience with Labview.

Interview with Professor Wellin

Consultant Interview
Interviewer: Jim Breunig
Consultant: Professor Wellin
Date 8 April 2008, Bioengineering lab

I asked professor Wellin a couple of questions on April 8th. I asked him if he would mind being a consultant for the project. He said he would and he said that there is a lot that can be done with the programming. It's currently functional, but I think if we get a computer engineer, it could streamline the programming.

Interview with Dr. Doolittle

Advising Interview
Interviewer: Jim Breunig
Consultant: Dr. Richard Doolittle
Date 9 May 2008, Dr. Doolittle's Office

I talked to Dr. Doolittle about biomechanics of the human hand. I want to know where I could get specific information pertaining to degrees of freedom of the human hand. He explained how some of the joints work, and the degrees of freedom of each joint. He also let me borrow a book about anatomy and it has some very helpful information about human hand biomechanics. He also gave told me that a good book is called Physiology of Joints by Kapandji. I plan to do some research over the summer and learn a little more. He also said that we would be able to take a look at a cadaver hand in the fall. I will be contacting him in the fall to take advantage of this.

Customer requested milestones, progress reports, and expected product

Dr. Lamkin Kennard plans to use this project for research. The product, above all, must maintain all of the directions of freedom of the human hand. The hand should also be scalable. A needs assessment and budget constraints are shown below.

Needs Assesment

Relative Importance of Needs

The needs shown above are weighed against one another. The table below shows the relative importance of these needs. A number 1 indicates a need that must be fulfilled and a number 5 indicates a need that should be fulfilled.

Relative Importance of Needs
Need Description Importance
Air Muscle Safety Air Muscles Should not explode 1
Cable Safety Cables should not break 1
Controls Safety Controls System should exhibit safe movements 1
Follow Regulations Follow RIT Rules 1
Distal Interphalangeal Joint Range of Motion Range of Motion of Distal Interphalangeal Joint 1
Proximal Interphalangeal Joint Range of Motion Range of Motion of Proximal Interphalangeal Joint 1
Metacarpophalangeal Joint Range of Motion Range of Motion of Metacarpophalangeal Joint 1
Robust All Parts of Hand should not break 2
Scalability Should be Scalable 4
Mechanical Optimization Improve Current System 2
Software Optimization Improve Current System 2
Easy to Use Should be Easily Operated 4

Customer and Sponsor Involvement

The team will be expected to carry out the vast majority of their interactions with Dr. Lamkin-Kennard. Dr. Lamkin-Kennard will be available for a series of meetings during the course of the project, and will meet with a group of teams during the beginning of MSD1 to lay out common goals, objectives, and philosophies for the sequence of projects. There will be weekly meetings throughout MSD I with the Dr. Lamkin-Kennard and the Project Manager. These meetings will be scheduled on a weekly basis.

Regulatory Requirements

Project Budget and Special Procurement Processes

The sponsor has allocated approximately $2000 to this project.

Each air muscle costs approximately $10

Each prototyped finger costs approximately $50

There will be numerous miscellaneous costs such as cables and other hardware depending on the design. I project that the total cost of the project will be approximately $1000. This figure is assuming that all of the current data acquisition devices are adequate for the design implementation. Data acquisition devices can cost several hundred dollars each, which would add greatly to the project costs.

Purchases for this track will be run through the Senior Design Department.

Work Breakdown Structure

Below is flow chart describing how the work will be broken down.

Image:Objective Tree.png

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