Table of Contents
- Current State:
At this time, the team is currently devising a number of solutions that fit well within the confines of customer and engineering requirements.
- Desired State:
The teams intended goal at this point in time is to move forward with a single solution that encompasses the best options for each subsystem with due consideration to their integration with one another. We would also prefer to have a number of secondary solution packages for risk mitigation purposes.
- Project Goal:
The goal of this project is to provide a market-ready, safe, motorized pediatric stander that accommodates all customer and engineering requirements.
Team Vision for System-Level Design PhaseThis phase primarily revolved around concept generation and determining where it was needed based on the general areas of the standard. The general areas include: the wheel-ground interface, external frame shape, environmental sensory, remote and primary control types and stander specifications. Through benchmarking, engineering analysis and feasibility testing, the all options were collectively exhausted and sorted to determine the best option for each area of the stander at this time.
During this phase, the team accomplished benchmarking, engineering analysis and feasibility testing in order to determine the best viable option for each of area of the stander with due consideration to each subsystem¡¦s integration. We are also in the process of creating a platform to mount and adjust castors to test wheel size, wheel placement, and maneuverability.
Conceptual Design Development
Systems Architecture OverviewThe general system architecture is as depicted in the diagram below. The Motorized Pediatric Stander is to be comprised of motors, environmental sensory, electrical components to connect and power these components and a control scheme to command and receive feedback from all subsystems.
Functional DecompositionIn general, the functional decomposition is broken down based on the stakeholders actively engaged with the motorized pediatric stander. The full diagram should be referenced to see how all of the sub-decomposition's, shown below, fit together to achieve the end goal of a functional motorized pediatric stander and accessible modification kit.
- Decomposition Color Key:
- Orange - Stakeholder
- Blue - Things we do not want to change
- Green - New features/functions
Concept Selection Criteria
- 1. Usability of the stander and secondary users
- 2. Overall size of the stander
- a. Does the modification cause the stander to be obtrusive?
- b. Does the modification add substantial amount of weight to the stander (i.e. causes the modification to exceed 20 lb. limit)
- 3. Amount of parts required
- a. will the modification component require specialized tools to attach to the stander?
- 4. Durability and fragility of design
- a. How long can the design be operable and run without issue?
- b. How fragile are the components, and what can we do to make them stronger (i.e. material selection)?
- 5. Proven concept (i.e. ability to control specific types of modifications for the wheel design)
- 6. Mindful interface/variability in primary user control input
- a. What are the cognitive abilities of the primary user?
- b. What are the physical abilities of the primary user?
- c. What is the variability within the design? Structurally and electrically?
- 7. Safety of the person and not changing the integrity of the device
- 8. Safety of the environmental surroundings
- 9. Power consumption
- 10. Cost
- 11. Ease of installation/assembly
- 12. Material availability
Conceptual Design Selection
We are looking to obtain feedback from Linda Brown about capabilities of the various control ideas and her opinions about their usability. Our desire is to purchase or find a LCD touch screen and raspberry pi to test and evaluate the difficulty of programming. Obtaining force resistant pads, mechanical buttons, and joysticks will allow us to evaluate the feasibility of having mulitple control schemes availible for the Motorized Stander.
Motor/WheelsAfter compiling the specifications on the type of movement and power required to satisfy all customer and engineering requirements, a list has been devised and narrowed down to a chart of potential candidates for motor selection. The chart with their respective descriptions is shown below:
A large feasibility consideration lies with battery life. The following table shows some basic assumptions and calculations. These numbers were based on past projects and preliminary research.
Similar research has been performed on the viable types of environmental sensory that are readily available. The charts below presents the pros and cons of each type of sensor that are being considered. There will be a mixture of sensors in the testing phase to accommodate each sensor's area of weakness. A chart of the potential candidates for sensors and their specifications are also shown below:
Conceptual Design Feasibility
Each system level design component was mapped to risks identified during the previous design review. Please refer to the live document for the most current version.
Plans for next phaseMSD I Plan
The individual plans for each team member are listed below: