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Entry  Tue Jul 30 09:20:18 2013, Giorgos, DailyProgress, SUS, HE output & DAC output/voltage follower IMG_4531.JPGSimulink_Draft_model.slx
    Reply  Tue Jul 30 11:14:16 2013, Koji, DailyProgress, SUS, HE output & DAC output/voltage follower 
       Reply  Thu Aug 1 11:50:02 2013, Koji, DailyProgress, SUS, HE output & DAC output/voltage follower 
Message ID: 685     Entry time: Tue Jul 30 09:20:18 2013     Reply to this: 686
Author: Giorgos 
Type: DailyProgress 
Category: SUS 
Subject: HE output & DAC output/voltage follower 

HE output

We tested the HE output and found that all the outputs were fine, except for the S1 board which saturated. This board was also the one with the odd phase function (when measured earlier in the summer). We realized that some components may have been disconnected (not enough soldering) and we easily fixed the problem.

DAC output - Voltage Follower

The output of DAC was lower than the one we expect. We measured the DAC output in V for different feedback filters and compared it to the value we would expect by converting the digital feedback of our computer from bits to volts. However, when the ribon wires connecting the DAC and the actuation conditioning boards (coils) is disconnected, we get sensible readings; the ribon seems to limit our output. It might be the case that the internal resistance of the DAC is large and that causes a huge voltage drop. We will then use a voltage follower configuration with an OP27, so that the current is not sourced from the DAC. We introduced a voltage follower in the 10 actuation boards (7 coils & 3 DC magnetic offset). Following, you can see the voltage follower configuration.

IMG_4531.JPG

Simulink Model

I also created a draft model to model our system, using Simulink. The matrix that determines the coupling of the 6 degrees of freedom still remains to be calculated.

Simulink_Draft_model.slx

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