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Unread 19-10-2015, 19:09
philso philso is offline
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Re: RoboRIO MXP Breakout

Quote:
Originally Posted by FrankJ View Post
That is not exactly simple. You are intercepting the PWM signal and sending out a new one with the trim added. I don't see this ever getting approved. (disclaimer: I have nothing to do with the approval process.)
I think you would unlock much more potential for controlling your motors by investigating using different motor control software algorithms and incorporating sensor inputs in innovative ways. You would not need approval from FIRST to do any of this.

Intercepting the PWM signals and then modifying the pulse widths is not a trivial thing to do. It will be even more difficult to do it well enough that you would consider submitting it for approval. As I stated earlier, it would take a lot of real-time processing horsepower to do this.

My day job is designing the hardware that goes into large (100 ~ 1200 hp), 3-phase motor controllers for industrial applications. I have never seen any of my employers, any of our competitors or any academic papers intercept the PWM signals and manipulate them in hardware. What is done by everyone in the industry is to have many software modes (Volts/Hertz, Vector Control, ...) for generating the PWM signals. Much of the research in this field is in improving the (software) control algorithms used to generate the PWM signals. It is often the quality of the software that gives one motor controller an advantage over another.