This may be a weird one, so please hang in there with me on this.
I have a large steel drum, its ~450kg. Measured to be 11.83kg/m^2 for its rotational inertia. (MOI).
On the end of it we have a VERY accurate laser cut disk. Has 4 teeth, 4 gaps. Equally spaced and all the same "delay".
When we rotate the drum we have an optical sensor which can measure the "delay" of its state, either on or off. Measurement is down to microsec's. So thats accurate enough for us. As the drum speeds up in rotation, the delay becomes shorter.
What we are struggling with is Angular Acceleration. Basically we need a way to tie all this together.
As for the actual practical application of this, think of a motorcycle dyno. As that what it actually is. I can provide pictures if so required.
We have some sample data recorded and so far we have had limited success.
We got the bike to 4000rpm, and held it and "calibrated" the drum rpm. Then as the bike increased or decreased rpm in that set gear, it perfectly showed what the engine was doing. So reving the bike to 12000rpm the dyno drum said "engine should be at 12000rpm" and it matched perfectly. We tried in several spots and also one "run".
We are struggling to get the power output to match correctly because math is not really our strong suit.
I have sample (open source) firmware for our hardware (teensy++, basically arduino) and some recorded data of one of the runs for analysis.
If someone can help me with what we may be doing wrong it would be GREATLY appreciated.
We are using gnuplot to make a graph of the saved data.
"I have a large steel drum, its ~450kg. Measured to be 11.83kg/m^2 for its rotational inertia. (MOI).
On the end of it we have a VERY accurate laser cut disk. Has 4 teeth, 4 gaps. Equally spaced and all the same "delay".
When we rotate the drum we have an optical sensor which can measure the "delay" of its state, either on or off. Measurement is down to microsec's. So thats accurate enough for us. As the drum speeds up in rotation, the delay becomes shorter.
What we are struggling with is Angular Acceleration. Basically we need a way to tie all this together.
As for the actual practical application of this, think of a motorcycle dyno. As that what it actually is. I can provide pictures if so required.
We have some sample data recorded and so far we have had limited success.
We got the bike to 4000rpm, and held it and "calibrated" the drum rpm. Then as the bike increased or decreased rpm in that set gear, it perfectly showed what the engine was doing. So reving the bike to 12000rpm the dyno drum said "engine should be at 12000rpm" and it matched perfectly. We tried in several spots and also one "run".
We are struggling to get the power output to match correctly because math is not really our strong suit.
I have sample (open source) firmware for our hardware (teensy++, basically arduino) and some recorded data of one of the runs for analysis.
If someone can help me with what we may be doing wrong it would be GREATLY appreciated.
We are using gnuplot to make a graph of the saved data.
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