Team Vision for Subsystem Level Build & Test Phase
Our goals for this phase were to begin prototyping the user controls and continue building both the mechanical and electrical subsystems of SailBot. This was accomplished through the following tasks that we planned to do during this phase:
- 3D print our first controller prototype
- Finalize test plans, specifically with user testing
- Complete an order for the remaining mechanical parts
- Begin building the linkage assembly
Our team accomplished the following:
- 3D printed prototype of the user controls
- Finalized designs for the feedback system and ordered parts for it
- Updated BOM to reflect the mechanical components purchase order
- Researched the process required for using fiberglass
- Continued debugging electrical systems
- Began manufacturing linkage assembly and gearbox
- Updated test plans, risks, BOM and problem tracking
Only minor updates were made to the test plans created last phase. Specifications and metrics for the target and ideal test results will be finalized as testing begins. Effectiveness of each test will also be assessed to ensure the results and conclusions from them accurately satisfy the requirements. The list of the tests and their purposes is shown below:
- Force Test - Simulate the forces of water acting on the tiller. Test durability and functionality of the tiller movement subsystem
- Battery Test - Ensure SailBot can perform for an entire sailing session. Testing durability and battery life.
- Water Test - Ensure every exterior surface on SailBot is water resistant and can endure various weather conditions.
- General Use Test - Confirm SailBot functions correctly as a unit
- User Test - Test that the controls are comfortable and easy to use with clearly displayed feedback.
- Installation Test - Ensure SailBot is portable and easy to install.
- Overrides Test - Confirm the emergency and discrete overrides work reliably.
We hoped to begin testing during this phase, but have not completed the building of the subsystems required for them yet. Requirements for human subject testing were researched, however, and our User Test is exempt from needing approval from the Human Subject Research Office (HSRO). It was determined that our test will not collect data on human behavior, but rather harmless data for improving our prototypes. We have reached out to Community Boating as well as some of our local contacts to ask for volunteers who would be willing to take part in our user testing. The accompanying questionnaire which will be used to document their feedback is linked here.
The following videos were taken to demonstrate some of the functions of SailBot:
Override Test - Override input is set to turn full left and when the override button is pressed the standard user input is ignored and the override controls the motors position.
Motor Limit Test - Motor moves to the left stopping when left limit sensor is activated. Motor moves right until right limit sensor is activated. In both cases the motor may return to center and move in the direction opposite their limit.
Motor Position Control Test - Motor moves to the left then returns to center when released. Motor then moves to the right and back all the way to the left until released, returning back to center.
Risk and Problem Tracking
Risks continue to be monitored and updated as progress is made on the project. Risk 2, 3, 14, 16 and 17 have been reduced in importance due to increased funding, improved designs and prototypes for user controls and mechanical part orders being delivered. Risk 20 was added as a result of the decision to coat the exterior of SailBot with fiberglass which we are still researching to see if it will be compatible and strong enough with the 3D printed material. Finally, risk 8 was increased due to issues that have arisen with the electrical communications and our lack of integration between subsystems at this point in the semester.
Importance was summed up for all of the risks and plotted to track the progress being made. Each phase, more risks are mitigated and their importance decreases as a result. Currently, we are down from 282 to 249.
Problem tracking began this phase as issues arose with both the mechanical and electrical subsystems. Currently, the most critical problems are Bluetooth communication errors followed by pulley interference with the motor. Other problems relate to the strength and availability of chosen materials. All but one of the identified problems have been solved and the remaining lead screw problem solution is in the process of being implemented. This chart outlines the process of solving each problem from initial identification to implementing and evaluating the solution:
More purchases were made this phase to get electrical components as well as materials for the mechanical assembly and user controls. An updated BOM and an overview of the ordering status from this phase are detailed below. We are still well within our new budget after obtaining additional funding from sponsors at the beginning of MSDll.
- Battery Charger
- Pulleys and Belt
- Aluminum Extrusion
- Metal Stock
Next (Final?) McMaster-Carr order:
- Sealed ball bearings
- Gas Spring
- Misc. Hardware
Possible Electrical components needed:
- Voltage Regulator
Functional Demo Materials
Include links to:
Plans for next phase
Next is the Integrated System Build and Test phase. Plans and tasks for this phase include:
- Print the remaining user control pieces for a complete prototype to test
- Begin user testing with the controller
- Manufacture and assemble linkage system
- Complete test bench
- Continue debugging electronics
- Test fiberglass on a sample piece to confirm strength and compatibility
- Begin integrating the different subsystems
Below are the three-week plans for each individual team member for the next phase: