Team Vision for System-Level Design Phase
Our goal for this phase was to come up with a high level idea of how we are going to fulfill all of the customer and engineering requirements for our project. We planned to do this through brainstorming, research, benchmarking, and discussions to come up with the best solution to fit the customer's needs. The table below illustrates what we accomplished during this phase.
|Develop an understanding of all necessary functions that the device will need to perform.||Solidified all customer and engineering requirements. Constructed a functional decomposition. Developed a systems architecture to determine how each subsystem will fit together.|
|Generate and discuss concepts for a system to perform all necessary functions.||Created a morphological chart for functions identified in the functional decomposition. Brainstormed methods to achieve each function.|
|Compare and analyze options.||Performed benchmarking analysis and Pugh charts for key functions to determine the best possible way to achieve them.|
|Analyze feasibility of design ideas.||Performed feasibility analysis for key functions to ensure that all customer and engineering requirements will be met, and it will be possible to incorporate into the high level system design.|
Some industry standards that we identified as relevant to this project are listed below:
- IEEE 802.15.4-2011 New standards for ultra-wideband (UWB) radio signals.
- CLSI AUTO5-A Laboratory Automation: Electromechanical Interfaces; approved standard.
- IEC TR 80001-2-2 Edition 1.0 2012-07. Application of risk management for IT Networks incorporating medical devices.
- IEC 62304 Edition 1.1 2015-06. Medical device software - Software life cycle processes.
Concept Development and Morphological Chart
Force Sensor Benchmarking
Location Sensing Benchmarking
Data Storage Benchmarking
Data Transfer Benchmarking
Feasibility: Prototyping, Analysis, Simulation
Force Sensor Feasibility
In order to confirm that the force sensor we choose will be able to measure the force of an individual's gait accurately, we need to make sure that the sensor can measure the individual's entire weight. For these calculations, we assumed that the sensor will need to measure up to 300 lbs, or 1334 N. The force ranges for each sensor are compiled in the table below.
|Force Sensor Options||Force Sensitivity/Range||Max Force [N]||Feasible? Y/N|
|Force Sensing Resistors||0.2 - 20 N||20||N|
|Load Cell - Button||25 - 1000 lbs||4448||Y|
|Load Cell - FlexiForce||0 - 4448 N||4448||Y|
|Array of Force Sensors - ThruMode Matrix||0.25 - 12.5 lb over 0.5 sq inch area||3531 [a]||Y|
|3000E Pressure Mapping - Tekscan||125 - 862 kPa||17670 [b]||Y|
[a] assuming the average area of a size 10 shoe is 205 square cm, or 31.78 square inches, the total force that can be measured per unit area times the entire area of the shoe. This also assumes that the array of force sensors will take up the entire shoe, which doesn't need to be the case.
[b] assuming the average area of a size 10 shoe is 205 square cm, or 0.0205 square meters, the force can be found by multiplying the pressure and the area.
Based on this table, all sensors except the force sensing resistor will be able to measure at least 300 lbs of force. However, there are other factors such as cost, size, and safety that will be considered before officially deciding which sensor to use.
Our total project budget is $2,000. Preliminary cost estimates for our top two configurations are in the range of $120-140. Given this information, the team is well on track to complete the project within the budget. Integration of the system and software licensing will be an additional cost we must consider. After this cost and the creation of two prototypes, the estimated cost of the project is around $1,000.
Data Transfer Feasibility
Current Draw Feasibility
Designs and Flowcharts
This link shows the F-Scan System by Tekscan, which is similar to the product we are trying to create.
This link shows the DWM1001 development boards working together to track location.
Plans for next phase
Team Goal for Weeks 8-11
- Finalizing the direction for each subsystem is the main goal of the next phase. Once each subsystem design is completed, then ideas and prototypes can be developed. This will give the team a clear path towards knowing which parts to purchase and include in each system and the entire system.
Individual Responsibilities to Achieve Team Goals
- Martine Bosch
- Decide which force sensor to use. (1 hour)
- Design attachment to foot. (3 hours)
- Design attachment to leg of a crutch/walker/cane. (3 hours)
- Determine what additional parts will be needed for attachment and begin prototyping. (4 hours)
- Nick Petreikis
- Assist in contacting tekscan to obtain a f-scan model for free (1 hour).
- Contact Texas Instruments using Dr. Beato’s contact (2 hours).
- Create budgeting plan (5 hours).
- Matthew Devic
- Work on microcontroller feasability (5 hours).
- Contact Decawave about DWM1001 triangulation system (2 hours).
- Finalize parts list with other lead engineers for all systems (8+ hours).
- Patrick Mylott
- Continue to update the gantt chart for the project. (3 hours)
- Help design how team will attach microcontroller and location system to force system. (8+ hours)
- Assist team with finalizing design ideas for sensors, batteries, triangulation system, and more. (6+ hours)
- Help Nicholas with the budget and possibly turning it into a time phased budget to help us predict the spending of the project team. (4 hours)
- Begin to develop prototype ideas and gather materials with the team. (8 hours)
- John LeBrun
- Design a detailed circuit for power delivery (4 hours)
- Analyze possible loopholes in location-tracking systems (2 Hours)
- Deliver donuts for the team (30 Minutes)
- Continue on with the weekly State-of-the-Project emails
- Erik Brown
- Finalize estimate of average walking speed for impaired individuals- data transfer rate (1 hour)
- Assist in developing prototype ideas. (3 hours)
- Assist lead engineers in developing test plan and ensuring designs/ attachments aren't affecting gait mechanics. (4 hours)
- Hrishikesh Moholkar
- Research the MCU and IDE to use for developing the firmware for sensor.
- Add more cases and improve the UML diagram for the sensor software.
- Help team in research.