Team Vision for System-Level Design Phase
Our goals for this phase were to:
- Gain a better understanding of the end user.
- Ability to maneuver while in the wheelchair.
- Consistency with requiring assistance.
- User's ability to attach device under their own power.
- Finalize engineering requirements as well as create
plans for preliminary testing.
- Fully understand how engineering requirements will allow us to meet customer requirements.
- Have each member spend time in the wheelchair without device attached as well as with the device attached and fully functional.
- Continue evaluating risk management.
- Brainstorm different concepts and ideas for a system
- Combine traits of concepts which were agreed upon to enhance the final concept.
- Select a concept to move forward with which utilizes positive traits from the concept collection criteria.
During this phase we accomplished:
- Development of a better understanding of the end user.
- Finalizing engineering requirements as well as create
preliminary plans for testing those requirements.
- All engineering requirements are closely related to the customer requirements.
- Generate multiple concepts and select one to move
- Concept selection criteria was combined to form the most effective concept.
- Each member spent some time in the wheelchair to gain first hand experience without the device attached as well as some time with the device attached and fully functioning.
- Review of CAD drawings used by team P16007.
- Revisions and updated the risk management document as needed.
- Further benchmarking against existing products and components to ensure that the selected design is feasible.
Functional DecompositionFunctional Decomposition was used to help develop a better understanding of how we are going to accomplish the task. At it's highest level, it answers the question "why?" and at each successive step down the chart, it begins answering the question "how?." This allows the ability to understand how each requirement will be met to eventually reach the end goal; a working wheelchair assistive device.
BenchmarkingThe following benchmarking process was performed to help develop an understanding of the various features of the existing prototype and how they compare to other products already existing on the market.
Concept DevelopmentThe following concepts were individually brainstormed and the key features of each concept are discussed below. These are preliminary designs meant to suggest improvements from the previous design prototype as well as add important features that will increase the functionality of the device. When beginning the detailed design stage, we plan to utilize the positive features decided upon in these concepts.
Feasibility: Preliminary Test PlansBefore the completion of the design and prototype, it is crucial to have an understanding of the metrics that will be tested. The following table discusses various tests and how the tests will be performed.
Morphological Chart and Concept SelectionThe morphological chart below was used at the beginning of our concept selection to ensure that all possibilities were considered. When considering designs, each section of this chart was used to help select a feature that will be included in the final design.
Concept Selection CriteriaSelection Criteria:
- Cost of device: It is understood that some of the features suggested in the morphological chart may be out of our budget and therefore be unreasonable.
- Ease of attachment: Attachment is one of the main customer requirements related to this design. It is crucial to consider this requirement when considering all concepts.
- Product weight: An important area of improvement from the previous prototype is decreased weight. Consideration of weight in each concept must be maintained at all times.
- Traditional use: By attempting to decrease the size of the footprint of the existing prototype, we hope to make the wheelchair easy to use in a traditional manner.
- Performance: Consideration of requirements including incline capability, battery life, speed, and other performance expectations must be maintained at all times.
- Improved quality of life: The end goal of this device is to improve the quality of life of the user.
- Storage: Storage and ease of access must be considered when selecting a concept relating to the attachment and detachment of the device.
- Time considerations: Some possible concepts may prove to be incredibly time-consuming. Time tables should play a role in every decision-making process.
Pugh AnalysisPugh analysis was used to compare our concept selection criteria with each of the preliminary design concepts in a quantitative manner.
- -1: Represents criteria inferior to the datum concept
- 0: Represents criteria meeting the level of the datum concept
- +1: Represents criteria superior to the datum concept
It is important to note then when using the previous prototype as the datum, several of our concepts appear to be superior. This is to be expected, as the goal of the prototype being developed is to improve upon the design created by P16007.
Designs and Flowcharts
Design Review MaterialsSystem Design Review Notes
Customer Interview NotesFull List of Customer Interview Notes
Plans for next phase
Team Vision for Next Phase:
- Develop working knowledge of current prototype to include its strengths, weaknesses, and areas of improvement.
- Resolve customer requirements and engineering requirements to have an expected end-state.
- Utilize benchmarking of other concepts to assist with refinement of device design.
- Assess and mitigate risks associated with the device.
- Calculate theoretical performances for product selection on the system overall.
- Simulate concepts applicable to device refinement.
- Create preliminary BOM and working budget.
- Prototype with available materials for any applicable proof-of-concept refinements.
Individual Plans for Next Phase: Individual Plans for Next Phase