What did you personally accomplish this week on the project?
This week, I worked further on our motor code to handle homing and stall detection, as well as fine tuning the movement for each actuating position. The latter was done this week after getting a sense of the exact layout and dimensions of the slider actuator. I edited the code to more precisely rotate the motors to specific positions. The homing function then utilizes the stallGuard functionality of the TMC2209 driver to move the motor towards one edge until it detects it (utilizing back emf measurements in the background). I also researched linear gear racks for our specific geared motors, which required identifying the measurement standard of our gears and then searching for a compatible rack. I also found out that the JST motor cable connectors identified before were slightly off so I need to order new molex picoblade connectors. My progress is on schedule, but I need to accelerate progress on assembling motors after receiving these parts next week.
In particular, how will you analyze the anticipated measured results to verify your contribution to the project meets the engineering design requirements or the use case requirements?
The anticipated results for testing of motor subsystem based on our engineering design requirements are the following:
– Actuating time between words: 500ms/cell (translates to 5 s/word)
– Motor power consumption: 1.2W
– Reliable usability: 6 hrs
To measure and verify the time testing results, I will feed in a long text input (10-20 words), upload Arduino code, and run the Python script, and finally start a stopwatch and “lap” every time the motor stops and moves to a new position. The time elapsed on every lap corresponds to the actuation time per cell. Based on these results, I might have to accordingly adjust the operating mode or power input to motors to satisfy design requirements.
Analyzing power consumption would require a much longer text file or simply running the motor on loop based on the timing results from above. After I figure out an average actuation time, I will hard code the number of steps the motor needs to run for that amount of time, repeat this movement in previous direction, and calculate power consumption over 5-10 mins in Arduino code.
Finally, I need to conduct failure testing over longer periods of time to satisfy the use case requirement of reliability over 6 hour periods.