Risk management:
The primary risk to our team’s success at present appears to be the changes caused by the recent pandemic. At present, we still don’t know what the plan is for capstone in the future now that CMU has switched over to remote instruction. This uncertainty has been rather demoralizing.
Since we’ll all be working remotely in the future, it’ll be far harder to collaborate on this project. As a contingency for team members falling behind, we can plan to have periodic Zoom meetings where we update one another, but this is no substitute for physically being present. There’s also the chance of one or more of us being infected, which is difficult to plan for. It’s hard to develop a contingency plan for the possibility of team members being unable to function effectively.
Assuming we are still designing the subject of our project, the main risk to the circuit design portion of the equatorial mount is the inaccuracy of circuit schematic simulation. It’s possible to take layout parasitics into account by placing estimated capacitances into the simulation window, but this isn’t a substitute for full-blown EM simulation. The main concern with respect to simulation inaccuracy is the shoot-through current spikes of the motor controller circuit. It’s been demonstrated in simulation that a specific value of gate resistor can control these spikes so that they don’t overly impact the circuit, but the existence of such things as gate inductances make the simulation output somewhat dubious. The contingency plan for mitigating such spikes at the moment is to simply place increasingly large gate resistors on the board, which has been shown to work in simulation.
As far as I know, no changes have been made to the existing system design.
Progress pic:
This week, the motor controller PCB was successfully laid out. The above is a 3D render of the resulting board.
Cheers,
Yuyi Shen
Note: Our team erroneously assumed that there was a status report due on March 7, and hadn’t realized we were meant to cover both weeks for this report. Therefore, please consult the following links for the remainder of the report:
March 7 Team report: http://course.ece.cmu.edu/~ece500/projects/s20-teamb1/2020/03/07/team-status-report-3-7-2020/
Kenny Ramos’s March 7 report: http://course.ece.cmu.edu/~ece500/projects/s20-teamb1/2020/03/07/kenny-ramoss-report-for-3-7-2020/
Joy Gu’s March 7 report: http://course.ece.cmu.edu/~ece500/projects/s20-teamb1/2020/03/07/joys-status-update-for-2020-03-07/
Yuyi Shen’s March 7 report: http://course.ece.cmu.edu/~ece500/projects/s20-teamb1/2020/03/07/yuyi-shens-status-update-for-march-7-2020/