Team Vision for System-Level Design PhaseThe goal for this portion of the project was to approach solving the problem in a non-solution oriented way. Completing processes such as the functional decomposition allowed for a customer and engineering requirement focused design process. This allowed for a wide range of design options to consider that were slowly narrowed down to a preliminary concept selection.
Improvements from Last Review
- Created a House of Quality (Click here to view House of Quality)
- Updated Engineering Requirements based on meeting with A and Leah
- Updated Gantt Chart
Accomplished Goals from Last ReviewAlaiya
- Research car batteries compatible with our car
- Compare and contrast our battery with other compatible ones
- Create battery decision matrix
- Design test for batteries
- Test our current batteries
- Research methods of steering for the child
- Create a decision matrix for child steering method
- Perform preliminary power calculations for the system
- Make visio model of functional decomposition
- Create a plan for the system level design review
- Pick up power wheels donation
- Make house of quality
- Research Power Wheels
- Research Go Baby Go!
- Research ASTM/ISO standards
- Prepare and conduct interview with customer
- Research and calculate engineering requirements
- Research and Select Microcontroller
- Research and Select Wireless Control
The main function for this project is to provide experimental stimulus and independence to the child. The 3 categories below are the ways to accomplish the main function.
Do no harm
Provide interaction with the world that the child can control
There are three main mobility aids for children with CP:
- Modified Ride-On cars such as those seen in University of Maryland's Go Baby Go! Program
- Powered Wheelchairs
- Gait Trainers
The main customer goal is to provide a mobility solution for A based off of a Go Baby Go! Design. However, benchmarking is useful in that it can provide inspiration on how to further modify our car. We have developed a set of selection criteria based on our functional decomposition to determine what the “best available solution” is:
- CP-friendly controls
- Parent can control if needed
- Provides mobility
- Allows the child to have social interactions
- Is easy to use for child, parent/caregiver
- Is safe to use for child, parent/caregiver, and environment
Cerebral Palsy (CP)
CP is a neurological disorder caused by a non-progressive brain injury or malformation that occurs while the child’s brain is under development. It’s non-life-threatening, so people with CP have similar life expectancy as a regular adult. CP is a little bit more common than people think; it occurs in every 2.1 per 1,000 babies. If our car design works well for A, then there’s a possibility to help many more children.
The effects of CP vary greatly. The main affect of CP is loss of control of certain body movements. Limbs can be stiff, and forced into painful, awkward positions. Coordination, muscle tone, and reflexes can also be affected. Because muscles affect how bones grow, those with CP tend to be shorter and height and are at a greater risk for scoliosis.
Because of the above symptoms, children around A’s age have trouble with hand-eye coordination, balance/posture, grasping objects, and just generally getting their muscles to perform the action they want. All of this will greatly affect the design of our car. We also have to keep in mind that the overall goal is to improve the quality of life for A; we will do this by giving him the ability to explore his environment, and promoting his ability to perform self-care tasks.
One-third of children with CP are non-ambulant and require the use of a wheelchair. Having a wheelchair is extremely important for kids with CP since mobility is important for the cognitive and psychosocial development of children. Wheelchairs can also provide a degree of independent mobility and reduce the dependence on caregivers. A recent study performed on children with CP has proven that the sooner a child with CP is introduced to using a wheelchair, the higher degree of independent mobility is achieved (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2933698/).
The average cost of a powered wheelchair is around $7,132. This is much more money than most families can afford. Because mobility at an early age is so important to a child with CP, our modified ride-on car can be an important intermediate step for families than cannot immediately afford a powered wheelchair. Children also are not generally given a powered wheelchair until the age of three. Our car is intended to be used by children aged from 1-3, and will be designed with the intention of being similar to a powered wheelchair. One of the most important components of a powered wheelchair that we may incorporate into our design, is a joystick used for steering.
- Ease of Implementation
- Level of Control and Feedback
Feasibility: Prototyping, Analysis, Simulation
Morphological Chart and Concept Selection
Pugh Chart Datum (developed using the morphological chart)
Child Controls Decision Matrix
Microcontroller Decision Matrix
Bluetooth Control Decision Matrix
Battery Decision Matrix
Designs and Flowcharts
Design Review MaterialsIncluded links to:
Plans for next phaseAllison
- Create a detailed plan for each system design (ex. Electrical system, restraint/seat system)
- Source a new battery or batteries
- Work with Austin and Alayia to design the remote controls system and the child control system
- Itemize BOM and reduce error to 5% or less for each item.
- Create spending tracker.
- Purchase Microcontroller
- Purchase components for power steering.
- Purchase joystick for child control prototyping.
- Work with Austin, Allison and Kathryn to create a control system for the child
- Work with Austin and Allison to design the remote control system for the parents
- Create a detailed plan for the electrical systems of the car with Allison
- Work with Austin, Allison, and Alaiya to create a control system for the child
- Help Mia design a restraint system for the child
- Continue communicating with Leah to make sure design meets standards
- Determine interface between controls and microcontroller
- Determine interface between drive components and microcontroller
- Connect controller to microcontroller with bluetooth
- Determine Motor and encoders required for electronic steering
- Create a system for attaching carseat to car
- Make a document of all ASTM/ISO standards for the project
- Update engineering requirements as the project continues