Overview of Status of Analysis, Design, Fabrication, Tests, etc.
The motor has been been purchased and we are preparing to test it with a Dynamometer in order to better evaluate the power requirements.
Dynamometer test results are expected on Monday 4/14
The pressure case endcaps and winching system designs have been finalized. We are ready to begin machining and 3-d printing some of the parts.
Accomplishments from Previous Week
We have finalized our first prototype's winching system and pressure case.
Purchased motor with an encoder.
Verified the validity of the using Spectra cable.
Bart asked for a report on our recommendations for components to purchase. The report is available under the "Docs" tab.
Submitted our prototpye design to our sponsor and had it approved.
Goals for Next Week (list names after each item). Use specific and measurable objectives.
Design a sensor that can detect when the drogue has been fully retracted. -Everyone
Finalize design of the inside of the case with fasteners, clips, etc. -Thomas
Test motor to obtain a torque versus speed curve, an efficiency versus speed curve, and power consumption measurement. Also, determine the lowest speed that the motor can be run at to overcome the friction in the rotary seal. -Matt, Jebsen and Merlin
Create a code for controlling the motor shaft speed - Merlin
Finalize the battery choice. - Jebsen
Research power regulation systems. -Jebsen, Johnathan
3-D print the winch casing and all support parts. -Matt, Johnathan
Fabricate the pressure case endcaps. -Thomas
Purchase 4" PVC pipe, gears, batteries, controller, and all components needed for the inside of the pressure case by Friday. -Everyone
Sponsor Comments from Last Meeting and Actions Taken to Address these Comments (indicate date of comments and if via email or in person)
Bart asked us to verifry that we could indeed use 1.4 mm diameter line and maintain a drag area ratio of 40:1. We can.
Bart told us to purchase the motor ASAP. Thomas purchased it.
Instructor Comments from Last Meeting and Actions Taken to Address these Comments (indicate date of comments and if via email or in person)
Professor Tustaniwskyj suggested that we use parts from the fishing reel in our first prototype. We modified the winch design o do this.
Professor Tustaniwskyj suggested that we check our work in the analysis of the motor. We decided to use the FCCR lab's dynamometer to test the motor.
Comments from Other Students in the Class (indicate date of comments and if via email or in person)
None.
Risks and Areas of Concern
We are still concerned about the long lead time in ordering parts through SPAWAR. Speaking with Bart in person, we confirmed that lead times are upwards of 2 weeks.
The controller we use may need to be fairly powerful, depending on whether or not the external sensors (the range finder and depth sensor) are self-logging. The sensors will be chosen by SPAWAR.
Resources or Information Required but not Available
A 3-d model, detailed drawing of the drogue's frame. Alternatively an actual drogue from Pacific Gyre.
Schedule
We are on schedule, but this week and next week will be very busy.
A full CAD model of the pressure case and winching system inside the drogue will be complete by Friday 4/18
Purchasing of all parts necessary for fabrication of the first protoype will be complete by Friday 4/18
Budget (list amount spent and amount remaining)
We have spent $120 through UCSD. Amount remaining- aproximately $280.
We have not purchased any parts through SPAWAR. Amount remaining-TBD
Progress on Report and Webpage
We wrote our first draft of the Background, Review of Existing Solutions, Statement of Requirements, Deliverables, Title Page, and Appendix. The draft is available in the "Reports" tab.