The initial trials of the device were conducted with the open-loop system. As seen in the figures below, there are obvious drift and disturbance errors present. It is not so easily seen in the sine wave photos, but it is very clear when the block M is drawn. The starting point and end point of the drawing should be the same, however they do not match up. Due to this obvious drift and disturbance error, our team decided to implement a feedback control system using 2 VEX 90-pulse quadrature encoders to read rotational position of the Etch-a-Sketch knobs, and feed this back to the motors.
Final Trials
The second set of trials was conducted with the closed-loop system. The following photos and videos show that the drift is notably smaller than with the open-loops system above.
The second set of trials was conducted with the closed-loop system. The following photos and videos show that the drift is notably smaller than with the open-loops system above.
The video below shows the robot drawing a sine waveform on the Etch-a-Sketch. This trial was conducted with feedback control.
No comments:
Post a Comment