Preliminary Detailed Design
Documents and photos for this phase can be found in the E - Preliminary Detailed Design Documents directory.
Team Vision for Preliminary Detailed Design PhaseSummarize: During this phase, the team intended to continue to prove the feasibility of the intended design both electrically and mechanically and also to build a prototype in order to prove the intended bones and muscles will dynamically move in the intended way. The feasibility and prototyping that we accomplished in this phase raised many more questions and concerns which are detailed below, however this is the perfect time for those questions prior to the detailed design review and before we start building.
Updated Documents from Phase I & Phase II
A link to the working document can be found here: Updated Docs
Prototyping, Engineering Analysis, SimulationPrototype of Forearm
- Motivation: Check the motion and degrees of freedom of the actual vs what we anticipated.
- Goal: Have a prototype that works in the intended way by the end of this semester.
- Progress: Have initial prototype and a list of concerns and issues that both the muscle subgroup and the bone subgroup are working to fix. Such as: too many degrees of freedom in the joints, unintended forces from the muscles that are causing misalignment and routing and location securing questions.
- Prototype wrists/joints:
- Used spare sheet metal from machine shop to manufacture
- CAD Models were made to show complete look at full system model
- Prototype bones:
- Motivation for not using anatomically correct
- At first, we decided to prototype the bones by 3D-printing however was too difficult and time consuming in this current phase to get the part to be anatomically accurate. We then used hollowed aluminium tubes to prototype the bones and used string to fasten them to the wrist brackets.
- Motivation for not using anatomically correct bones:
- Create motion simulation of bones to show desired motion
- Adjust design if need be to accommodate risks that arises
- Prototype hand:
- Concept: Lego Hand
- Method: 3D Printing
- Material: PLA
- CAD Model:
- Implement hand to wrist joint
- Forearm Assembly:
- Shows visual representation of what the forearm will look however at this point is missing necessary joint mechanisms and integration with electrical components.
- A clear casing was made around the forearm to show relatively the space where the Dragon skin will be. Our chosen concept was that the dragon skin acts as a sleeve that goes over the forearm and stretches as the forearm size changes.
- Implement joint connections & try to simulate hand and forearm movement
- Design and model concept for adjusting forearm size
- Implement skin model for visual aid to check for clearances between parts
Iterative activities to demonstrate feasibility, including assumptions you made in your analyses or simulations. Have you completed sufficient analysis to ensure that your design will satisfy requirements? Have you included all usage scenarios in your modeling?
Feasibility: Prototyping, Analysis, Simulation
- Feasibility Analysis
- Goal is to decide which motor to select based on Engineering Requirements using basic principal learned in Dynamics Class
Drawings, Schematics, Flow Charts, Simulations
- Diagramming Electrical Components such that it can be
easily built in the next phase.
- Goal: Create a logic circuit, and show the progression from block diagram to fritizing diagram to final schematic.
Bill of Material (BOM)
Design and Flowcharts
- Updating Circuit Diagram
- Updated Circuit Diagram to include the movement in the flexion/extension plane, and also included a motor driver required to power the motor.
A link to the working document can be found here: Risk Assessment
Design Review MaterialsPreliminary Detailed Design Review Presentation
Plans for next phaseProject Deliverables Completion Plan:
Key Technical Questions we intend to work towards answering next phase:
- Will the tremor be able to work with the
“eating motion” using our current design?
- Will the muscles for the tremor be affected by the motion from the flexion/extension of the elbow?
- Is there a way that we can rout the muscles so that they aren’t affected?
- If there is not, how can we overcome it? Ie. Programming? Building in a ratcheting mechanism?
- Will everything fit within the size constraints of
- Will the brackets be about the size of the actual joints?
- Will the muscles perform if they are restrained within the arm?
- Will the skin perform as expected to human skin?
- Will the dragon skin have the necessary friction and hardness to replicate a real arm?
- Will the dragon skin be moldable into the necessary shapes for the test arm?
- Will the dragon skin withstand the necessary number of cycles of taking the device on and off?
- How much dragon skin will we realistically need?
- Will our electrical subsystems work as
- Will the electrical components be compatible?
- Will there be enough power to supply all components?
- Will Arduino be powerful enough? Frequency it can provide? Does the driver determine this?
- Will the sensors provide us with useful data at a valid sampling rate?
- How do we add in a safety shut off?
Below are our individual 3-Week Plans for Phase 4: