Robotic Arm Assist

Extending an Arm Toward the Future

Assisting Tecnalia's venture in designing a rehabilitation robot to aid stroke victims in their recovery. Our mission is to design and build a set of add-on modules to extend the functionality of an existing arm rehabilitation robot for Tecnalia.

Development and Project Goals
TECNALIA's Arm Assist Robot is an assistive robot for the rehabilitation of patients with upper limb neuromuscular impairment, specifically for patients who have suffered from a stroke. This assistive robot is accompanied by a tele-rehabilitation platform, thus allowing rehabilitation at home under supervision from the therapist by its quantitative evaluation.

ARMASSIST represents a major technological breakthrough which allows TECNALIA to address the growing market demand for personalized care. This initiative was born to meet the needs of the 15 million people who suffer brain-vascular damage every year; of that figure 5 million suffer permanent disability.[]

The Robotic Arm Assist team, provided by the University of Idaho, will work through the capstone project to further develop the rehabilitation robot. The team will add to the overall functionality of the robot by providing TECNALIA with modules that will increase the current lift function, ability to rotate wrist, and ability to open and close the patient's hand.

Design Goals
Our design goals for the project are to build a grip, twist and lift modules to incorporate with current design with few alterations. Our modules should be passive and able to stand alone, with the capabilities of being powered and used in conjunction with one another depending on the needs of the user.

Design Specifications
 Grip Module 


 * Sense full grip 1-2° (individual fingers not necessary)


 * Incorporate vibration feedback when full grip is complete


 * Help individuals complete tasks when necessary

 Wrist Rotation Module 


 * Allow rotation of ±90°ideally (minimum ±60°)


 * Help individuals complete tasks when necessary

 Arm Elevation Module - Lift Module 


 * Allow 4” of arm lift without lifting the device (2” minimum)

 Other  Modify GUI to show output from modules and display them in a useful manner for the future development of games.

Project Learning


Throughout the project learning section of our design process we were able to conclude several general ideas in order to start progress in the correct direction. Primarily, we have gained a greater understanding as to what is occurring in a stroke victim’s body from the lesion in the brain to the synergies that react when the person attempts to send a call from the brain to the body. The severity is rated on a Rankin Scale (RS). This understanding will help us design the modules specifically to help the victims in the RS that we are directed towards.
 * Learn more: Stoke or cerebrovascular accident (CVA) [] []


 * Learn more: Muscle coordination and synergies []


 * Learn more: Clinical evaluation of stroke patients [] []

We have also gained much understanding in the hardware in use. Being able to look at the robot and visualize the scale of module we need to produce was helpful in comprehending the module’s needs. Research pricing and variability of strengths in hardware was helpful in producing a very rough budget. After researching the PCB hardware necessary to handle each of these modules, we were able to understand it's limits. Specifically, the research into components that measure distance and force was invaluable to our preliminary research and understanding how to design a functioning module that will meet the specifications provided for us.


 * Learn more: Initial pricing research, aluminum []


 * Learn more: Initial research on PCB

Finally, researching the ideas and current prototypes of the same general concepts on the internet was very important in understanding what the biggest challenges will be for us (i.e. making the design simple enough to actually use). This was very helpful in attempting to see flaws in other designs and well as general concepts that could be incorporated into our design, while being aware of patent-ability.


 * Learn more: Potentiometer []


 * Learn more: Load Cell []

In conclusion, we believe the amount of knowledge that we spent in the project learning section of our process will be very valuable in our conceptual design process along with throughout the entire design.

Morphology Chart Summary
Each member of the team was asked to sketch 3 to 5 design concepts to analyze. The designs were evaluated by general feasibility in a series of meetings. The ideas that were found infeasible were reconsidered and combined with other ideas to be made feasible again, in order to have a wide variety of viable options to consider.

Designs were then evaluated on capability, ranging from 1 to 5, the highest score being the most capable. Each specification was given a value (found immediately before the description) that represents its weight in reference to the other specifications; higher values are directly correlated to its importance. These numbers were then put into a morphology chart; the designs with the highest weighted totals were then further scrutinized to ensure that we were choosing the most advantageous designs.

The designs were then analyzed upon the following specs (1 being incapable 3 being moderately capable and 5 being very capable):

Grip Design's Specifications and Values

 * Help Open – (1) does this module assist in opening the hand


 * Help Close – (1) does this module assist in closing the hand


 * Accuracy – (1) would this module be able to accurately measure its task


 * Adjustable – (1.25) would this module be adjustable to all sizes


 * Easy to put on – (1.5) would this module be easy for the user to put on


 * Passive – (1) would this module be able to be made passive


 * Active – (.25) would this module be able to assist in making these movements for the user


 * Simplicity – (.25) how complex is this module


 * Machinability – (.6) how easy would this module be to machine in shop


 * Cost – (3) overall cost of this module (five being most cost efficient)


 * Integration – (.75) how easy would this module be to integrate into the current prototype


 * Longevity – (.9) will this module be a long lasting device


 * Safety – (2) will this module be safe for the average at home user

Lift Design's Specifications and Values

 * 2” – (1) would this module have a range of 2”


 * 4” – (1)would this module have a range of 4”


 * Accuracy – (1) would this module be able to accurately measure its task


 * Force required – (1.25) how much force would be necessary for the user to apply


 * Weight – (1.25) weight of module in device


 * Simplicity – (.6) how complex is this module


 * Machinability – (.9) how easy would this module be to machine in shop


 * Cost – (3) overall cost of this module (five being most cost efficient)


 * Integration – (1.5) how easy would this module be to integrate into the current prototype


 * Longevity – (.75) will this module be a long lasting device


 * Safety – (2) will this module be safe for the average at home user

Wrist Rotation's Specifications and Values



 * ±90° – (.6) would this module have a range of 90°


 * ±60° – (1) would this module have a range of 60°


 * Accuracy – (1.1) would this module be able to accurately measure its task


 * Easy to put on – (1.5) would this module be easy for the user to put on


 * Passive – (1) would this module be able to be made passive


 * Active – (.4) would this module be able to assist in making these movements for the user


 * Simplicity – (.75) how complex is this module


 * Machinability – (.75) how easy would this module be to machine in shop


 * Cost – (3) overall cost of this module (five being most cost efficient)


 * Integration – (1.25) how easy would this module be to integrate into the current prototype


 * Longevity – (.9) will this module be a long lasting device


 * Safety – (2) will this module be safe for the average at home user

Completed Morphology Chart found here []

Anthropometric Research
In order to have an ergonomically sound device, each portion of the device needs to be built in reference to the human body. Therefore, the 1st, 5th, 10th, 50th, 90th, 95th, and 99th percentile measurements of the length of the forearm, hand, and fingers along with the breadth of the four fingers, and the hand were taken of both male and females, with the intention of designing the modules to be able to fit 5th through the 95th percentiles.

Anthropometric data found here []

Concept Development
Following the preliminary research, the top rated modules from the morphology chart were chosen. These modules were then drawn in Solidworks and were analyzed, searching for errors and miscalculations.

Grip Concept Development




This simple Linear Grip Concept Design on the left allows the hand to be completely opened and resists being closed, which combats the gripping synergies, but does not allow for a natural grasp. The more complex Multi-grip Concept Design on the right simulates a more natural grasp which allows to assistance in opening and closing of the hand, that would combat gripping synergies as well.

Wrist Rotation Concept Development




The wrist rotation concept design on the left has a center rotation pivot, giving the user a centralized rotation. This is intended to simulate a natural movement. The wrist rotation concept design on the right is a half ring design, this rotation is a fully stabilized rotation. Stabilization along with the natural movement associated with the half ring would be beneficial for the user.

Lift Concept Development




The Scissor Concept Design on the left is a very simplistic lift mechanism that takes up a relatively small space and completes the action in both passive and active forms. The Linear Lift Concept Design is a lift mechanism that can be both passive and active but needs alteration of the original robot.

Concept Analysis
In order to analyze each design, and have a full understanding of how each design functions, the prototypes are manufactured and assembled. Steven Witkoe and Kadrie Swanson have taken leading roles in the machining and 3D printing processes. A big thank you goes out to our mentors; Russ Porter, Jonathan Teske, and undergraduate student mentors.

Grip Prototype Analysis
The grip module has been built using a 3D printer and 3D printing filament. Seven separate pieces were uploaded onto the printer, printed and assembled with screws, hook and loop fabric, and foam.

Analysis of this prototype:

This design successfully completes all of the specifications from our client. Modifications will be made to individual pieces to make it more comfortable to the user.

Scissor Prototype Analysis
The prototype scissor modules have been built using 1/8th inch aluminum plate for the folding support links, pins, and ball bearings for smooth movements. The top and bottom platforms for bracing the links and holding the potentiometer will be built out of aluminum as well.

Analysis of this prototype:

This design successfully completes all of the specifications from our client. Modifications will be made to the base system and the edges of the links will be curved, but the over all design will remain the same.

The scissor module will be sensed with a potentiometer near the base pin, in order to get a reading of this pin we will attache gears to rotate and sense the amount of rotation.

Wrist Rotation Prototype Analysis
The wrist rotation first prototype has been built out of 1/4" steel plates and 1/4" cylindrical extruded and 1/4" square aluminum.

The ring design was designed in Solidworks, coded in MasterCAM and then cut using the CNC machine. The dual rings will glide on a V shaped bearing allowing rotation. This rotation will be sensed using a gyroscope in the box that will hold the gliding rings. We need to continue the machining process and have a full assembly to gather a full analysis on this module.

Computer Interface Prototype Analysis
The computer-module interface has been built using java script. Progress continues.

Final Product
Throughout the semester, through a variety of prototypes, we have adjusted many of our original ideas to better fit the desires of our client. This process has not only taught us how to quickly and accurately make new adjustments but also to foresee problems more effectively.

Consultants
  Dr. Joel Perry 

Project Manager - TECNALIA, Rehabilitaiton Technologies Dept., Health Division

Adjunct Faculty - University of Idaho, Mechanical Engineering

  Dr. Matthew Riley 

Assistant Professor

http://www.uidaho.edu/engr/me/faculty/matthewriley

  Chris Ohlinger 

Fall Semester Graduate Student Mentor

  Jon Teske 

Spring Semester Graduate Student Mentor

Meetings
Frequently updated agendas [] and minutes []available on dropbox.