Print PDF
Favorite
Email
Step 20Final Thoughts
While the Mad Dog Robot is an adequate proof of concept prototype there are still a few areas for improvement.
The neck tilting mechanism can tilt the ruler back and forth very rapidly – but, when Tic-Tac boxes are nearly full, this very rapid movement generates high enough inertia forces such that Tic-Tacs can become jammed. To address this problem, the program initially runs the neck mechanism at rather slow speed when Tic-Tac boxes are full. A second compensating measure is cutting down Tic-Tac box tops which also reduces jamming.
Secondly, the next centering mechanism is not precise. Due to coasting, the neck does not always stop where it should. For this reason, the centering hole is larger than would seem necessary so “leading edge” light shuts the motor off early so the neck hopefully coasts to the proper position. It is desirable to move the neck at the slowest possible speed, but this can cause stalling when the battery charge state is on the low side. So, the program initially begins with a high pulse width modulation duty cycle and then every time it misses or overshoots, the next attempt is at a lower duty cycle thus going slower and decreasing overshoot likelihood.
On the things that work well list: the wiper motor and drawer slides provide quite and smooth movement of the platform, the mechanical jaw holds the ruler very firmly, and the mechanical jaw mechanism pulls the actuation cable with plenty of force and sufficient length of travel.
The neck tilting mechanism can tilt the ruler back and forth very rapidly – but, when Tic-Tac boxes are nearly full, this very rapid movement generates high enough inertia forces such that Tic-Tacs can become jammed. To address this problem, the program initially runs the neck mechanism at rather slow speed when Tic-Tac boxes are full. A second compensating measure is cutting down Tic-Tac box tops which also reduces jamming.
Secondly, the next centering mechanism is not precise. Due to coasting, the neck does not always stop where it should. For this reason, the centering hole is larger than would seem necessary so “leading edge” light shuts the motor off early so the neck hopefully coasts to the proper position. It is desirable to move the neck at the slowest possible speed, but this can cause stalling when the battery charge state is on the low side. So, the program initially begins with a high pulse width modulation duty cycle and then every time it misses or overshoots, the next attempt is at a lower duty cycle thus going slower and decreasing overshoot likelihood.
On the things that work well list: the wiper motor and drawer slides provide quite and smooth movement of the platform, the mechanical jaw holds the ruler very firmly, and the mechanical jaw mechanism pulls the actuation cable with plenty of force and sufficient length of travel.
| « Previous Step | Download PDFView All Steps | Next Step » |
 |
Add Comment
|
