Project SummaryCurrently our end user is confined to a manual wheelchair. Owing to the fact that it is not powered or assisted in any way, she feels a loss of independence due to relying on a secondary pusher and staying primarily in flat areas. Even slight inclines pose a significant challenge on her own, and as such we are looking to implement a supplemental power solution.
Current renditions of driven wheelchairs involve custom builds, which are highly expensive and heavily strain the daily performance of the impaired party. In our case, the customer would prefer the option to maintain her independence if desired. Ideally, rather than a completely driven wheelchair, this project will research and launch an assisted wheelchair prototype. The end result will aid users and facilitators while minimizing customer upkeep.
In a manual wheelchair the user or facilitator must spend additional physical energy to maintain control of the wheelchair when traversing an incline. An assisted wheelchair supports the user in everyday use of the wheelchair, giving the operator options to utilize supplemental power. A driven wheelchair completely eliminates the need for a facilitator as the user is in complete control. However, the use of a driven wheelchair has significant cost and can result in muscle atrophy or weakness of the user due to inactivity. A fully driven wheelchair is not the most desirable solution when the user does not have access to a wheelchair-supported vehicle and/or wants to utilize upper body strength. Therefore, the assistance should not impact the manual usage of the wheelchair. The design must satisfy these requirements while avoiding the excessive price and inconvenience associated with a fully driven wheelchair.
The goal of this project is to engineer an assisted wheelchair. For the first semester of this project, the group will be dealing with customer requirements, engineering conditions, and coming up with a sound theory/solution. The actual prototype will be built and showcased in the second semester.
Project DeliverablesThe objective of this project is to produce a working prototype assist device which can be added to a standard manual wheelchair.
- Prototype solution attached to a wheelchair.
- Documentation including design documents and pricing information.
- Test data.
Customer Requirements (Needs)
Current Revision: 9
Revision Date: 09/28/2015
Engineering Requirements (Metrics & Specifications)
Current Revision: 6
Revision Date: 10/15/2015
- Incline angle comes from ADA code 4.8
- In Use Length/Width requirements based on ADA code 4.13, doorway clearances.
- Budgeting for each system.
- Federal Regulations pertaining to wheelchairs and handicapped accessible.
- Design reviews, prototype deadlines at the end of MSD2.
- Weight under 50 pounds.
- Folded up volume fits within car trunk.
- Unfolded width fits through standard doorway.
- Usable all day.
- Does not impact manual usage.
House of Quality
Current Revision: 3
Revision Date: 09/28/2015
Current Revision: 2
Revision Date: 10/01/2015
Design Review Materials
Plans for next phase
Team Vision for Next Phase
- Resolve all customer needs through Engineering
- Ensure that every Engineering requirement has a clear and concrete impact on satisfying every customer need. As it is, some of the dimensional requirements have a very loose/low correlation with satisfying the customer. (Whole follow up, can be done with Mechanical and Electrical Subsystems)
- Complete Systems Design for Engineering Review.
- Whole: Discuss power source pros and cons, decide on single method. Obtain a wheelchair to follow with Mechanical and Electrical analysis.
- Mechanical: Evaluate footprint constraints, discuss method of driving the wheelchair, perform basic dynamic analysis of wheelchair, potentially begin modelling framework (Nicholas, Dat, Alan)
- Electrical: Discuss potential power sources, weigh different driver arrangements (reword, how the wheelchair is driven i.e. one motor, two motor, 5 or such). User Interface designs and subsequent power requirements (though they should be negligible), wiring management (Jason, Brad)
- Evaluate results from concept generation.
- Present findings from each subsystem for review/questions/reevaluation
- Consolidate results from Mechanical and Electrical Subsystems to determine interface between the two. (whole team)
- Continue Risk Management.
- Mechanical: Assess theoretical possible static and dynamic changes to wheelchair behavior based on max and min engineering requirements (namely weight)
- Electrical: Any potential exposure risks, safety of power source, mechanical durability of system relative to other options.
- Assess skills and resources needed.
- Skills needed to execute the designed plan
- Mechanical: Machining work, interface design
- Electrical: UI generation, power electronics, and control systems.
- Calculate performance limitations.
- Goes with Systems Design, from decided design calculate max performance possible considering a particular patient.
- This seems to be mostly cross considerations, max weight of user, max incline/max speed all based on power source
- Create a test plan.
- Whole Team: Try out a day in the wheelchair to assess difficulties/effort.
- Mechanical: Design roll/tip over test, dynamic change test (differences in inertia, rolling distance, etc.) , center balance test (don’t want the wheelchair to bank towards one direction, symmetry important), Vibration and impact test.
- Electrical: Design UI Evaluation test, power source life test (single use, and overall if possible), power source recharge test, if applicable, and motor control and power consumption test.
- Team Vision Document