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Author Topic: Negative Feedback on Schematic  (Read 462 times)

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Offline SylvestreTopic starter

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Negative Feedback on Schematic
« on: October 07, 2013, 10:05:53 PM »
Hello everyone,

As some of you may know, I am building a rescue robot that’s main function is to find and extract victims from a dangerous situation.  I am looking for all the negative feedback (constructive criticism) I can get so I can fix it before I go on to order the parts.  From my perspective, everything appears A-OK, but I need another perspective.  So with that said, is there anything you see wrong with this schematic.?

Here is the link to my schematic http://engineeering.weebly.com/schematics.html

Please ask any questions you may have

Thanks

Offline Tommy

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Re: Negative Feedback on Schematic
« Reply #1 on: October 08, 2013, 05:53:02 AM »
Quote
I am looking for all the negative feedback (constructive criticism)
Sylvestre, I see no control circuits for motor brakes?.also having kill switching on each motor could
cause issues(if one relay sticks, or if one relay fail, could be a problem),IMO dropping voltage for the
sabertooth and motor brakes would be less prone to problems.

IMO five cameras would be better then two with panning/titling.

Tommy


 

Offline jwatte

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Re: Negative Feedback on Schematic
« Reply #2 on: October 08, 2013, 09:35:19 AM »
I see no separate sensors for self-test and diagnostics.
What if one of the fans fail -- would the robot be OK? If so, why are the fans there? If not, how would the robot know something's wrong?
Same thing for each other necessary component -- how would you detect failure in order to achieve safe shutdown/self-disabling?

Offline SylvestreTopic starter

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Re: Negative Feedback on Schematic
« Reply #3 on: October 08, 2013, 01:05:21 PM »
Thank you for the great feedback Tommy and Jwatte

Quote
I see no control circuits for motor brakes?

The control circuitry is embedded into the Sabertooth motor driver. I can control deceleration through software

So you're saying I'd be better off without the relays?  Im sure there is another way I can implement a kill switch using the Sabertooth so that shouldn't be a problem.

Quote
What if one of the fans fail -- would the robot be OK? If so, why are the fans there? If not, how would the robot know something's wrong?
Same thing for each other necessary component -- how would you detect failure in order to achieve safe shutdown/self-disabling?
That's a very good point.  Similar to a 'check engine' light on a car.  I can't think right now because my brain is fried (just had a big test), but I will think of something tonight unless you have any suggestions.
« Last Edit: October 08, 2013, 01:10:58 PM by Sylvestre »

Offline Tommy

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Re: Negative Feedback on Schematic
« Reply #4 on: October 08, 2013, 05:40:49 PM »
Quote
Quote
I see no control circuits for motor brakes?

The control circuitry is embedded into the Sabertooth motor driver. I can control deceleration through software
Sylvestre, it is true you can deal with acc/dec of the motors with the sabertooth, but the sabertooth has no outputs for
motor brakes.

So you're saying I'd be better off without the relays?
having relays on each motor could be a problem, if just one of the relays fail your device is going to turn circles.

move the relays to the power for the sabertooth, that way both motors are shut down.
I'd keep them both wired in series, supplying power to the sabertooth, that way if one
of them fails the other would still remove power from the sabertooth.

Tommy

Offline SylvestreTopic starter

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Re: Negative Feedback on Schematic
« Reply #5 on: October 08, 2013, 08:01:21 PM »
Quote
Sylvestre, it is true you can deal with acc/dec of the motors with the sabertooth, but the sabertooth has no outputs for
motor brakes.
Ok I will take that into consideration.

Quote
move the relays to the power for the sabertooth, that way both motors are shut down.
I'd keep them both wired in series, supplying power to the sabertooth, that way if one
of them fails the other would still remove power from the sabertooth.
Ok one problem.  It is bad for the Sabertooth to cut power while in operation.  That is straight from DimensionEngineering

Offline Tommy

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Re: Negative Feedback on Schematic
« Reply #6 on: October 09, 2013, 03:41:18 AM »
Quote
Ok one problem.  It is bad for the Sabertooth to cut power while in operation.  That is straight from DimensionEngineering
Sylvestre, better to be bad for sabertooth than bad for People or Property, as long as your relays also
remove power from the motor brakes the sabertooth should be fine.

the sabertooth has a problem when the motors become generators(sabertooth powered down while motors turning)
motor brakes keep this from happening.

Tommy
« Last Edit: October 09, 2013, 05:32:34 AM by Tommy »

 


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