September 22, Dr. Andrew Rawicz School of Engineering Science Simon Fraser University Burnaby, British Columbia V5A 1S6

Transcription

1 September 22, 2015 Dr. Andrew Rawicz School of Engineering Science Simon Fraser University Burnaby, British Columbia V5A 1S6 Re: ENSC 440 Project Proposal for Solegait Pods Dear Dr. Rawicz, Please find attached our proposal for a mobile gait analyzer, which gives an overview of our project for ENSC 440. We would like to build an insole with embedded pressure sensors to observe how a patient walks, which then sends data to a mobile device to see whether their planted foot rolls slightly inward or outward. Our proposal goes over the details of our product, the biomechanical analysis, our proposed engineering solution, the risks and benefits, the potential marketplace, the estimated project timeline, as well as the project's costs/expenses and team members. Our company is founded by five engineering students in various fields of study. The members include Shaquile Nijjer, Zachary Nunn, Karsten Harder, Alexandra Talpalaru, and Ashley Lesperance. If you have any questions or concerns, feel free to contact me by phone at or by at kharder@sfu.ca. Sincerely, Karsten Harder COO Solegait Enclosed: Proposal for Solegait Pods

2 Proposal for an Assistive Rehabilitation Device Named: Team Members: Shaquile Nijjer Alexandra Talpalaru Zachary Nunn Ashley Lesperance Karsten Harder Contact Person: Alexandra Talpalaru Submitted to: Dr. Andrew Rawicz Steve Whitmore School of Engineering Science Simon Fraser University Issue date: September 28 th, 2015 Revision: 1.1

3 Executive Summary We have all heard the hype about being physically active. To restate, walking and running has been shown to decrease the chances of developing osteoporosis, heart disease, diabetes, obesity and even dementia [1]. Not to mention that walking is what allows us to get places and interact with other people. Therefore, walking and running is not just for the athletes. The ability to walk without pain is something that all able people take for granted. As physical beings, injuries or disabilities that prevent us from walking without pain cause immense physical and psychological traumas. The biomechanics of walking is formally known as gait. Gait is the repetitive process of moving a relatively large mass using only a subset of muscles, nerves, tendons, and joints. Although performing the actions of walking requires a small portion of our muscles and joints, it is not isolated from the remaining organ systems. Improper gait over time not only causes stress on the lower body but can also affect the hips, knees, posture and the spine. Our bodies communicate improper functionality through pain. Gait related injuries can occur quickly, as in the case of athlete injuries, or can develop over a long period of improper mechanics. Unfortunately, pinpointing the underlying cause and rehabilitation is often a long process. Physicians and physiotherapists are our experts in providing rehabilitative techniques for injuries. Current techniques used by medical professionals for evaluation include an assessment of the symptoms, localization of the pain, and visually determining gait patterns using treadmills, force plates, and sensor detecting cameras. These methods are lengthy, expensive, and can only be found in a laboratory setting. In addition, without numerous consecutive visits, and a thick wallet, physicians do not acquire longitudinal data. Our goal is to develop a rehabilitation assistive device capable of analyzing a portion of the variables of gait that lead to injuries. We propose to do so by developing a shoe insole with an array of embedded pressure sensors. Pressure data will be obtained during walking and will be set to a mobile application and recorded. The application will then display the data for visual processing, by the individual or the professional, and will also internally determine if the subject exhibits any of the common ailments incurred from improper gait. The purpose of this device is to help the subject pinpoint the cause of his walking pain, speed up and monitor rehabilitation, and prevent pain due to improper gait mechanics. Solegait is a partnership of five engineering science students in different specialties. Together we all share a passion for developing this device to help society be proactive about pain management and rehabilitation. The present document will outline the plan and design of our device which we expect to be completed by November 30 th, 2015 and cost approximately $450 which we will acquire from various funding sources including ESSEF. ii

4 Table of Contents Executive Summary... ii List of Tables... iii List of Figures... iii 1. Introduction Company Details System Description Biomechanical Analysis Engineering Solution Scope Benefits Risks Market Competition Research Rationale Project Timeline Project Cost/Expenses Conclusion... 9 References List of Tables Table 1: Outlining the Various Applications and Benefits of the Pods... 6 Table 2: Cost Breakdown for the Solegait Pods Device... 8 List of Figures Figure 1: Mechanics of the Gait Cycle [2]... 3 Figure 2: Vertical GRF During Gait [2]... 4 Figure 3: Components of the Solegait Pods Product... 4 Figure 4: Gantt chart depicting the Solegait Pods timeline and milestone deadlines... 8 iii

5 1. Introduction Gait analysis, analyzing movement patterns of the entire body during walking, is a critical first step for physicians and physical therapists in assessing the severity of a patient's lower limb injury. Typically, the therapist will observe (from the rear) the degree in which the patient rolls their planted foot inward (inversion) vs. outward (eversion) during one typical stride. If the patients planted foot typically rolls too far inward, or too far outwards this can lead to improper rehabilitation of the injured structure and multiple long-term debilitations. However, when physicians and therapists observe a patient's foot dynamics during gait, it is difficult to provide a precise analysis. As they observe, they estimate the degree of inversion and eversion; therefore, they may only be aware when large variances from normal tendencies are present, and smaller variances often go unnoticed. These smaller variances may lead to long term chronic or severe injuries. Solegait Pods is a solution for physicians and therapists to provide an accurate depiction of their patient s foot dynamics during gait. The objective of this project is to create a pressuresensitive insole which transmits data to an application on a mobile device. This application is intended to create a plot of the pressure distribution across the patient s entire sole. Given this information, the therapist can determine the correct amount of inversion and eversion of their patient s foot which will help create a more specialized and effective rehabilitation program. The product may thereupon be used throughout the entire rehabilitation process in order to track the patient s progress. This proposal document will outline the devices functionality, specifications, as well as other possible uses. It will provide a brief overview of proper biomechanics and foot dynamics during gait, project timeline, as well as design considerations, and an overview of the current market and market competition. 2. Company Details Shaquile Nijjer Chief Executive Officer (CEO) Shaquile is a fourth year Biomedical Engineering major at the Simon Fraser University. He has acquired industry experience via co-op at Macdonald Dettwiler and Associates in which he designed a signal processor for satellite images, and has also gained experience in the field of Biomedical Engineering while working with MENRVA Biomedical labs at SFU. His multidisciplinary skill set for this project includes: Biomechanics, Physiology, Circuitry, and Programming. Zachary Nunn Chief Technology Officer (CTO) Zachary is a fourth year Engineering Physics major at Simon Fraser University. He has hardware work experience from his year of co-op at Ballard Power Systems for doing fuel 1

6 cell membrane research and testing, which will allow Zachary to greatly understand and implement the thin film sensors we will be using. He has completed previous Arduino related projects with complex circuitry and sensors, which combined with his course and work experience, will make the project hardware, circuitry design, and sensor implementation his biggest contributions. Karsten Harder Chief Operating Officer (COO) Karsten is a fourth year Systems Engineering major at Simon Fraser University. He completed his first two co-op semesters at Sierra Wireless as a Software Test Developer. He gained experience analyzing and testing embedded wireless modules, performed manual and automated test cases, and writing AutoIt scripting language. Throughout his studies, Karsten has developed skills in both hardware and software design experienced in C++, assembly language, troubleshooting, and hands on skill with electrical circuits and wiring. Alexandra Talpalaru Chief Information Officer (CIO) Alexandra is a fifth year Biomedical Engineering Science major at Simon Fraser University with a strong passion for information research and learning about new technological advancements in the medical field. She has recently worked in a lab focused on methods for image processing of brain scans to help develop early diagnostic methods for Alzheimer s and Parkinson s diseases. In combination with course related knowledge, her biggest contribution to the project will be in physiological research, signal processing and data analysis. Ashley Lesperance Chief Financial Officer (CFO) Ashley is a fifth year Computer Engineering Science major and Computer Science minor at Simon Fraser University with an affinity for computer systems and the algorithms that drive them. He gained experience with mobile and web application development during course projects, co-op and personal endeavors. His main interest however lies in the backend systems that do the heavy lifting and had the chance to be exposed to such systems at BlackBerry Ltd. during his one year co-op. Ashley s main focus for the project will be architecting and implementing the frontend and backend software systems. 3. System Description 3.1 Biomechanical Analysis The objective of Solegait Pods is to quantify and evaluate everyday gait using insole embedded pressure sensors. Gait is a descriptor of the manner in which an individual 2

7 advances its center of mass (COM) over a distance, by walking or running [2]. As illustrated in Figure 1, two lower limbs work together by alternating planting, pushing against the ground, and swinging, in order to produce motion. To facilitate walking and to move the COM forward and upward, enough force must be applied by the foot on to the ground to produce an equivalent ground reaction force (GRF). The center of pressure (COP) and GRF are measures used to quantify and compare gait kinetics. COP and GRF can be measured by pressure sensors attached to the sole of the foot during walking and running for the purpose of normal gait analysis, rehabilitation, and disease diagnosis. Figure 1: Mechanics of the Gait Cycle [2] A normal gait stride consists of a stance and a swing phase [3]. As can be seen in the left most schematic of Figure 1 [2], during the stance phase the foot makes initial heel contact with the ground, followed by flat foot, and concluded with a forefoot push-off. The proposed sensors will capture the stages of pressure distribution on the load bearing foot during all of the periods of the stance phase as the other limb swings to complete a walking stride. The swing phase of the non-load bearing limb also influences the loading response pattern of the stationary foot. One complete stride occurs from initial heel contact to when the same foot contacts the ground a second time. Typical normal gait vertical GRF patterns consist of peaks at heel impact and at forefoot push-off during walking as depicted in Figure 2 [2]. During running, only one large GRF peak is measured when the subject lands on the heel or the toes, depending on style. Lateral GRF peaks indicate the position of the COM and the effort the subject is putting into stabilizing the motion. GRF patterns of normal gait vary slightly in individuals with different walking styles, cadences, and mass. However, careful control of these variables using treadmills and normalization can produce a strong baseline. Improper gait is an indication of decreased performance, injury, possibility of fall, or a more serious health diagnosis. 3

8 Figure 2: Vertical GRF During Gait [2] Monitoring gait patterns is useful for performance, rehabilitation, fall prevention and disease diagnosis. In general, proper gait reduces the risk of chronic pain or injuries due to overstressing particular muscles or joints. Physically active individuals, or athletes, benefit from consistent gait monitoring by being able to assess changes that can be made to improve performance, or rehabilitate an injury. Individuals who spend a lot of time on their feet, like nurses or construction workers, also greatly benefit from gait monitoring and early correction. Health professionals in senior homes can also monitor the likelihood that a patient will fall. Monitoring gait patterns using wearable sensors of high-risk individuals and comparing them to normal gait can lead to correcting form and preventing injury or diagnosing health diseases. 3.2 Engineering Solution Our engineering solution of Solegait Pods must collect pressure data from the user's gait, and analyze it in a way to present on the user interface so the user can visualize and understand there gait. To do this we will use Force Sensitive Resistors (FSR) to collect pressure data mapped by the foot and convert this data into an understandable unit such as Newton's (N) with the Arduino. The data will be transferred to the user's phone via Bluetooth, then mapped and analyzed with an algorithm we must design so that the gait can be compared to certain walking patterns. A flowchart of our described system is represented in Figure 3 below, as well as a breakdown of each part and a short description why each part has been chosen. Figure 3: Components of the Solegait Pods Product 4

9 Force Sensitive Resistor (FSR): An FSR is made from a conductive polymer, which has conducting and non-conducting particles suspended within [4]. The polymer has a low conductivity in an initial state, and when pressure is applied the polymer is compressed which causes the particles inside to get closer together thus increasing the conductivity where pressure is applied. This increase in conductivity, or decrease in resistivity, causes a change of voltage with pressure. This relationship between pressure and voltage across the polymer is the first step of the solution of Solegait Pods. FSR's was chosen as the pressure sensor because of its low cost and high durability from constant stress and impact, which is crucial in a shoe. A possible problem will be the precision of this sensor. Arduino: Arduino is an open-source microcontroller based company with software support in Java. Arduino is widely used in devolvement projects because it has the ability to connect to and read sensor data. Arduino was chosen as our microcontroller because of its ease of use with sensors as well as the large variety of interchangeable products that will allow us to greatly reduce the size of our product by switching to smaller Arduino microcontrollers that the company supplies. The first devolvement of Solegait Pods will use the Arduino Mega, this is due to the 16 analog inputs that we will use to read voltages from the FSR [5]. Memory can be added to the Arduino with shields if the need of temporary memory in the fault of communications errors with the user's phone. The Arduino Mega is also compatible with bluetooth transceivers through its serial peripheral interface (SPI) pinouts. Arduino can do all the functions that Pods will require, collect data, store data, and send data, making it the ideal choice of microcontrollers. Bluetooth: To connect the data that the Arduino receives to the user's phone we will be using a Bluefruit. A Bluefruit is a bluetooth device that connects to an Arduino through its SPI pinouts and will send data to an Android or IOS device. The Bluefruit breakout uses bluetooth low energy which will be important in the reduction of power loss of a wearable device such as the Pods [6]. Bluetooth was chosen as the wireless connection because the range of Bluefruit is ten meters which will be more than enough distance to guarantee a connection from the Arduino to the user's phone, as well as the reliability of the connection. Phone: Once the data has been collected and transmitted to the phone, we have at our disposition a relatively powerful smartphone processor that can do processing, connect to the internet and push the data to the cloud for other applications. The application that will communicate to the Pods will be run on an Android device written in Java. Android was chosen as it has the largest market share, a wide variety of shared libraries and any 5

10 modules written for the application will be cross platform for platforms that support the Java Virtual Machine (JVM). We also chose to do processing at this point in the system due to the processing power of modern smartphones and to reduce latency, providing realtime feedback to the user. 4. Scope 4.1 Benefits The Solegait Pods has several benefits which can significantly affect how a person should walk. During the patient's walk, they will be given feedback from a physician or physiotherapist on proper foot dynamics. This will greatly benefit the patient as the physician can recognize the information, and provide practical improvements on how the patient should walk. The transmitted data sent to the physician s mobile device creates a plot of the pressure distribution making it user friendly and easy to read. Without this knowledge, the patient may suffer serious injuries and may have trouble walking in the future. The Pods can be especially beneficial for the elderly or during a patient s rehabilitation process. A patient with previous lower body injury may walk differently even if it s not quite noticeable. The physician can then use the Pods to determine the significant amount of inversion or eversion to apply in order to aid their rehabilitation process and prevent long term injuries. Our product is also relatively light, and provides an extra layer of padding connected to the sensors making it comfortable to walk in. Essentially, the Pods product is beneficial for everyone providing a user-friendly interface, while remaining reliable and affordable. The following table provides, but is not limited to, various populations that could benefit from the device. Table 1: Outlining the Various Applications and Benefits of the Pods Population Athletes Seniors People affected by diseases which affect gait People with neurological disorders Application Performance and rehabilitation Fall prevention or fall detection Diabetes, arthritis, obesity Parkinson s, Huntington s, Cerebral Palsy Another benefit of the Pods and its accompanying app is the data collected and how researchers could use the data further understand gait related injuries. The data from the Pods will be sent to the mobile application and this can be pushed to the cloud where the data can be stored and computations run on it. Furthermore, an application program interface (API) 6

11 can be made for the system meaning that researchers can write their own algorithms or application for data analysis or patient treatment. The extensible nature of the API server opens up a lot of future developments using the Pods. 4.2 Risks Possible risks to consider and address in designing Solegait Pods include biocompatibility, electrical shock hazard, and heat management [7]. All materials directly in contact with the skin must be biocompatible and not corrode due to perspiration or friction. In addition, all electronic components must be properly isolated and not dissipate unsafe amounts of leakage currents. Lastly, a proper cooling system must be implemented to manage any buildup of heat in the microcontroller during data collection and processing. 5. Market The potential demand for our product is very large, as it is designed for every person and comes in various sizes. A study is shown that 1 in every 10 people have heel spurs, which is an abnormal growth of the bone on the bottom of the heel bone that may be caused by an abnormal gait, posture or walking [8]. Possible treatments include orthotics, surgery, or physical therapy. The physical therapist can use the Pods to examine the proper amount of force applied throughout the foot to help treat heel spurs. Another serious irregularity which can lead to injury is overpronation. Overpronation is when, after the heel-strike, the foot rolls more than 15 degrees inward to meet the ground [8]. This can cause serious injuries to the foot, shin and knee, and may lead to shin splints, Achilles tendinitis or plantar fasciitis. A study shows that between 50 and 60 percent of runners are considered mild pronators, while 20 to 30 percent are severe overpronators [9]. Ultimately, we want to cut down on injuries and provide treatment to help prevent further damage to the lower body. 5.1 Competition Unsurprisingly, there are various competing companies with devices that wish to achieve similar results as the Solegait Pods. However, Solegait looks to make a financially viable product for the average consumer, something that other competing products have not yet achieved. Current solutions for gait analysis and patient rehabilitation are strictly aimed at the medical institutions and can easily cost ten times the cost of the Pods. Even if the consumer was willing to pay the high cost, some companies only sell to registered businesses making it inaccessible to the average consumer [10],[11]. Other similar products have also failed to get off the ground despite initial interest, Solegait looks to learn from these mistakes and bring Pods to the world [12]. 7

12 6. Research Rationale Given less than 4 months to finish the project, we will demonstrate a working demo with research given into a patient s foot dynamics and all possible injuries related. Further research will be done in the use of the technology we use, such as the Arduino, Bluetooth transceiver, various fabrics and sensors. With these parts, we will implement a design that is cost efficient, cheap and reliable. Finally, research will be done in regards to learning a patient s rehabilitation process, and their interaction with physicians and physiotherapists. 7. Project Timeline The following tables summarize the expected design timeline for the Solegait Pods. We have chosen to omit documentation deadlines, and only include deadlines and milestones which pertain to the design of our device. The following table depicts our intended timeline for our product. Figure 4: Gantt chart depicting the Solegait Pods timeline and milestone deadlines 8. Project Cost/Expenses Table 2 summarizes the cost breakdown for this device. Table 2: Cost Breakdown for the Solegait Pods Device Product Number of units (Estimate) Price per unit ($) Force-sensitive Resistor sheet USD Conductive thread USD Arduino Mega 1 80 USD Bluetooth tranciever 1 25 USD Fabric 1 10 USD Shoe insoles 1 20 CAD Batteries(9V) 1 20 CAD *Extra sensors(in case of ~150 CAD failure)+s&h+tax Total Cost ~450 CAD 8

13 9. Conclusion Solegait company consists of a team of engineering students who are highly dedicated to the development of an assistive device to aid a patient s rehabilitation process and correct their foot dynamics. The Solegait Pods is a low cost solution to more accurately define imbalances in the user's walking patterns, and as a result, inhibit any chronic injuries in athletes, or bone and muscle degradation of older adults. The Solegait Pods is designed to provide therapists, physicians, and everyday people a cost effective solution to solve their gait related injuries. Furthermore, Solegait is a company which supports the advancement of medical research; therefore, with the added benefit of a cloud server, researchers have the opportunity to gather open source data for their own benefits. Referring to the Gantt chart within section 7, the Pods is a device which can be properly designed within the designated time. Our cost breakdown and potential funding source prove that this device is an effective everyday solution to a largely overlooked problem. 9

14 References [1] Ageuk.org.uk, 'Walking and how it helps prevent certain health conditions', [Online]. Available: [Accessed: 26- Sep- 2015]. [2] J. Dicharry, 'Kinematics and Kinetics of Gait: From Lab to Clinic', Clinics in Sports Medicine, vol. 29, no. 3, pp , [3] W. Tao, T. Liu, R. Zheng and H. Feng, 'Gait Analysis Using Wearable Sensors', Sensors, vol. 12, no. 12, pp , [4] Wikipedia, 'FSR', [Online]. Available: [Accessed: 24- Sep- 2015]. [5] Arduino.cc, 'Arduino - ArduinoBoardMega', [Online]. Available: [Accessed: 24- Sep- 2015]. [6] T. others, 'Bluefruit LE - Bluetooth Low Energy (BLE 4.0) - nrf8001 Breakout [v1.0] ID: $19.95 : Adafruit Industries, Unique & fun DIY electronics and kits', Adafruit.com, [Online]. Available: [Accessed: 24- Sep- 2015]. [7] H. Zeng and Y. Zhao, 'Sensing Movement: Microsensors for Body Motion Measurement', Sensors, vol. 11, no. 12, pp , [8] WebMD, 'Foot Pain: Arch, Ball, Heel, and Toe Pain Causes and Treatments', [Online]. Available: [Accessed: 27- Sep- 2015]. [9] Runner's World, 'Overpronation, Explained', [Online]. Available: [Accessed: 27- Sep- 2015]. [10] M. Insoles, 'Medilogic Insoles', Noraxon USA, [Online]. Available: [Accessed: 28- Sep- 2015]. [11] S. User, 'Science & Research - Moticon', Moticon.de, [Online]. Available: [Accessed: 28- Sep- 2015]. [12] Runnr.me, 'Runnr.me Run. Understand', [Online]. Available: [Accessed: 28- Sep- 2015]. 10