NSF Undergraduate Design Competition

Introduction

Muscle balance is defined as “a relative equality of muscle length or strength”; muscle groups can become unbalanced when the body is forced to activate the muscles on only one side of the body. For upper body imbalances specifically, symptoms also include back pain, shoulder impingement, headaches, neck pain, and rotator cuff tendonitis among others [1].

Those with upper extremity disabilities, more specifically those with limited use (or complete disuse) of a forearm, hand, and/or wrist, often fall victim to muscular imbalance. The objective of this project is to create an affordable, accessible grip aid to be used for weight training. By giving disabled individuals the ability to use more exercise equipment, incidences of muscle weakness, imbalance, and their related symptoms will be reduced.

Methods

The GripAssist is an orthotic lifting utility created to facilitate the autonomous exercise of individuals with upper extremity impairment. The full assembly consists of three main parts: the hand and wrist attachment, the bar adapter sub-assembly, and the strap fastener sub-assembly.

To use the device, the user inserts the male socket of the of hand and wrist attachment into the socket adapter of the bar attachment, then slides the male socket over into the socket housing. The user then can maneuver the extruded fin on the hand and wrist component over the lever of the locking mechanism to rotate the component, safely securing the attachment into the bar adapter. When finished, the fin can once again be used to unlock the device and the user can detach from the bar.

The assembled device can be used for various exercises and weight lifting equipment: free weights, cable machines, pushing exercises, pulling exercises, and bars of varying diameters. This makes the GripAssist multi-faceted and able to be used in numerous workouts without the need for extra attachments or straps.

Discussion

Although there are currently gripping aids in the market, devices specific for gym goers are either costly (upwards of $289), tedious to put on, and/or unable to provide users the ability to perform the exercises that they want. This is inconvenient for athletes that exercise on multiple types of equipment throughout each workout [2]. The GripAssist is an easy to use, cost effective, and multi-faceted devicethat aids disabled athletes in their workouts.

Acknowledgements

This work was supported by the University of Alabama Mechanical Engineering Department. Thank you to Dr. Beth Todd and Dr. Nima Mahmoodi for their help and advice.

References

[1] Page, P et al., Assessment and Treatment of Muscle Imbalance: The Janda Approach, 5-8, 2010

[2] Active Hands Gym Pack Deluxe, “Products”, Activehands.com, 2018.

Introduction

While many amputees show great adaptability to tasks without fully regaining complete hand function, the inability to perform certain fine motor movements creates a functional need for prosthetic finger systems that enable improved hand function. 3D printing leads to inexpensive and scalable solutions to fit pediatric needs [1]. 3D printing also gives options to rapid prototype and come up with multiple iterations of the model. Due to the subject being a preadolescent boy, 3D printing also leaves the option to change the scaling of the prosthetic as he grows.

Methods

This is a body-powered, cable-driven prosthesis that leverages existing hand/wrist functions to actuate the prosthetic fingers. While grasping, movements include prehensile, prismatic, and circular grasp. To move the subject’s fourth phalanx, a wire is connected to the distal portion of the third phalanx. This wire runs through a designed channel imitating the webbing of his hand to the distal portion of the fourth phalanx. The cable in the system is wound in tension. When the distal phalanx of the third phalanx moves, it moves the distal phalanx of the fourth phalanx in the same motion. This system can be analogous as to how a tape measure is tightly wound [2] and is showcased by Figure 1.

Figure 1:CAD Design of Current Iteration

Additionally, a thumb has been prototyped. Through the use of a ratcheting mechanism, it can be repositioned along a single axis and prevent backwards movement. This is to aid in gripping by creating a wedge-like hold on heavier objects, such as brooms and hockey sticks. The thumb is positioned by the other hand.

Results

The cable-induced system shows promise. More work is required for a functional prototype. As a proof of concept, the joint can be 3D printed in a flexible material and manipulated by cable. Increased efficacy and durability are needed for proper implementation.

While the thumb also has potential, to survive the rigors of a young patient, strengthening is necessary. It would be ideal to add a second ratcheting system for a second axis of movement.

Discussion

Stability and durability prove to be the next areas of focus for the prostheses. This requires more substantial prototypes. 3D printing may be the solution, but bracing is needed to prevent the shearing forces of everyday life.

Acknowledgements

This work was supported by the National Science

Foundation under Grant No. (NSF-CBET 1510367).

References

[1] Zuniga, J et al, BMC Res. Notes 8, 10, 2015.

[2] Ming L et al., Appl. Mech. Mater, 568-570, 899-903, 2014.

Hippotherapy describes the prescribed use of horse motion in physical or non-physical therapy. It has been used to treat patients with disabilities such as PTSD, multiple sclerosis (MS), autism spectrum disorder (ASD), ADHD, cerebral palsy (CP), depression, down syndrome, neuromusculoskeletal dysfunction, osteoarthritis, and post-stroke patients¹.

Positive effects from horse movement can be seen in motor coordination, muscle tone, postural alignment, stiffness/flexibility, and strength. Changes are often also seen in the respiratory, cognitive, sensory processing, balance, and speech/language production functions and may occur as a result of improvements in postural and motor changes.

Often times, hippotherapy is not feasible for patients who could benefit from it due to financial considerations, difficulty mounting a horse, and risk of injury1. Usually, patients take weekly hippotherapy sessions that cost around $80-$115, which can total over $5000 in a given year². Other obstacles include adverse weather conditions, difficulties accessing riding centers, fear of horses, and allergens³.

As such, our team has developed a low-cost, portable, and user-friendly robotic hippotherapy simulator. This device is intended for home use for all types of patients that need to use hippotherapy and is to be affordable for families that do not currently have access to hippotherapy.

The current design, seen in the figure below, consists of a Stewart platform (a mechanism that allows for electronic position control with 6 degrees of freedom), a seat with adjustable foam overlays (used to change the width of the seat to accommodate as many patients as possible), and a housing with wheels to protect and move the device. PID feedback control of the motors is gained via Hall Effect potentiometers connected to each motor shaft. A user interface connected to the Arduino allows for the operator to select various gaits of choice.

The device was designed with the end user in mind and is easily reconstructable, with little to no machining skills necessary. Only basic electronics and construction skills are required to build the device. All parts can be found off-the-shelf at local hardware stores or purchased online. A website with detailed assembly instructions and troubleshooting tips has been created for this purpose⁴.

ACKNOWLEDGEMENTS

Our team would like to thank Mr. Harrell Huff and Mrs. Carolyn Huff for their generous contributions to make our capstone design project possible.

REFERENCES

[1] Han, J et. al, J. Physical Therapy Science, 26:309-311, 2014

[2] Quest - Article - Not Just Horsing Around - A Quest Article https://www.mda.org/quest/article/not-just-horsing-around

[3] Ball, C. G. et al, The American Journal of Surgery,193(5):636-40, 2007

[4] https://hipposdontlierice.wixsite.com/stewie

Introduction

It is estimated the US has around 2.2-2.7 million people who use some type of assistive mobility device and of which 30% are power wheelchair users [1]. Some common characteristics between the wide range of disease states that lead to power wheelchair use are loss of motor skills and/or fine motor skills, sensory impairments, stiffness, muscle weakness, and lower fatigue threshold [2]. Thus, going out in the rain may prove to be a challenging task involving the need for dual protection of their electronic controls and themselves.

Methods

The circuit was constructed on a soldering board. A box was designed, and 3D printed to house the switch, circuit, and power supply. The aluminum frame was cut and welded together and holes drilled for the attachment of the motors and to allow the wires to be contained inside the frame. The rotation pieces to hold the back and rotating ribs were 3D printed. The lower half of the attachment bracket was milled to the size of the headrest mount to allow easy attachment and removal of the device. The clear canopy was cut and sewn together and coated with Rain-X to increase rain runoff.

Results

WIC Dry is an automated umbrella specifically designed for power wheelchair users. Figure 1 below shows the constructed prototype. The device attaches to the chair through an interchangeable piece that can slide in and out of the existing headrest attachment frame on the back of the chair. Therefore, the piece can be sold separately and purchased based on the specific power wheelchair the user has while the rest of the device remains the same, allowing for universality between models. This also allows the user to attach and remove the device whenever they need to since it is not permanently fixed to the chair.

Figure 1: Deployed and retracted configuration of the device.

Discussion

We meet with our client on April 27th and spoke about improvements to make for the next iteration. Since the PVC fabric is thicker and heavier material the motors did not have enough torque to sufficiently control the deployment and retraction of the fabric as compared to our practice pattern from cotton. We need a motor with a higher torque, a thinner/lower gauge fabric, and reduce the diameter of the ribs to 1/8" instead of ¼" to lower the weight.

Acknowledgements

Many thanks to our client, Philip Klebine, for all the insights related to being a power wheelchair user. We are also thankful to Dr. Abidin Yildirim, Steven Thompson, Dr. Alan Eberhardt, and Justin Koch for their helpful input through our design process.

References

1. Flagg, J. Wheeled Mobility Demographics. In Industry Profile on Wheeled Mobility; Rehabilitation Engineering Research

Center on Technology Transfer: University at Buffalo, Buffalo, NY, USA, 2009.

2. Langtree, I. (2015, March 03). Physical & Mobility Impairments: Information & News. Retrieved October 01, 2017, from

https://www.disabled-world.com/disability/types/mobility

INTRODUCTION

Essential tremor (ET) is the most common movement disorder in adults age 65 and older [1]. This represents nearly 2.5% of the US population. ET most commonly affects the upper limbs and is often highly disabling [2]. The most common treatments include medications and surgery. It has been estimated that as many as 50% of patients with ET cannot tolerate the medication or have disabling tremor despite receiving treatment [1]. Surgical treatments include deep brain stimulation, superficial brain stimulation and focused ultrasound thalamotomy. Some proposed approaches have reduced tremor through impedance methods [3], unbalanced mass actuators [4] and shape memory alloys [5], thus reducing tremor aptitude. Other approaches include anti-tremor utensils and other devices held in the hand. The scope of our work was to design and test a mechanical device to reduce the severity of tremor across multiple tasks. We focused our project on designing a low-cost, wearable device to reduce ET.

PRODUCT DESIGN

The prototype uses fluid flow to create an angular momentum vector to stabilize the tremor. The angular momentum vector acts perpendicular to the plane of fluid rotation, and the corresponding gyroscopic force resists the deviation of the hand caused by the tremor. A pump is used to circulate fluid through the tubing wrapped around the user’s forearm.

METHODS

A 2k factorial design was used to evaluate four prototype factors and their influence on the effectiveness of the prototype. The four factors included: flow rate of the fluid, tube size, number of coils around the user’s forearm, and the wrapping pattern. The best design configuration was determined using a SolidWorks Flow Simulation (Figure 1a). A testing apparatus was constructed with i) a weighted mannequin arm, ii) springs across the elbow joint, iii) a rumble motor, iv) an Arduino microcontroller, and v) a Shimmer IMU to measure the acceleration of the hand. Flexible tubing was wrapped around the forearm and connected to a pump to circulate fluid around the arm. Tremor reduction was characterized by acceleration magnitudes.

RESULTS\DISCUSSION

Experimental testing found that the fluid device showed both an increase and a decrease of 0.31 m/s2 in the ET generated by the testing apparatus. This indicates that the feasibility of this device as designed is limited to small tremor amplitudes. The prototype showed no influence on tremors with higher severity. All design specifications, with the exception of the tremor acceleration reduction, were met. Additional testing is suggested to incorporate an adaptive control system that can generate destructive wave interference causing a controlled decrease in tremor amplitude.

ACKNOWLEDGEMENTS

This work was supported in part by NSF under Grant 1159885 and the University of Utah’s Mechanical Engineering Senior Design Program.

REFERENCES

[1] M. Zappia, et al., J. Neurol., 260 (2013), pp. 714-740

[2] RJ. Eldble., et al., Curr Neurol Neurosci Rep., 353 (2013), pp. 13(6):353

[3] S. Pledgie; K. E. Barner; S. K. Agrawal; T. Rahman., et al IEEE Transactions on Rehabilitation Engineering, 8 (2000), pp. 53-59

[4] E. Rocon, J. Gallego, J. Belda-Lois, J. Pons., et al Tremor Other Hyperkinet Mov (NY). 2012; 2: 02-77-495-1.

[5] S. Pittaccio, L. Garavaglia, C.o Ceriotti, F.Passaretti, et al., J Funct Biomater. 6 (2015), pp. 328-344.

FIGURE

Figure 1: a) Simulation visualization of fluid flow b) Physical prototype of the wearable tremor dampening device