Laton Wrote:
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> Cerberus:
> The one think especially hard to understand is the
> use of the motors packed tightly together. Why? I
> always heard of skipping and heatissues. But why
> would you pack them together? (No rhetorics, I
> would really like an answer to that.
> Honestly.)(Maybe for heating the glass?)
I do not have Cerberus myself, but there is one obvious reason why to put motors as far away as possible from the pulley which turns the spectra line upward. It is to minimize nonlinearity between motor turn (in degrees) and carriage movement (in milimeters).
The point is that the line is being reeled on/off a drum which is on the corresponding motor shaft. This moves the point where the line touches on the drum vertically (up/down) from the center position on the drum. This movement changes the angle at wich the line bends around the pulley at the corresponding tower base. I do not know exactly how Cerberus is done but in a simplified situation lets mark the maximum angle between a horizontal plane and the line from the drum to the pulley as α, lets the distance from motor shaft to the pulley be marked as d, and lets the maximum (up/down) movement of the touch position (of the line on the drum) from the drum center be marked as x. Then x is a fixed constant (depends on the drum diameter, fishing line diameter and the cerberus height). The introduced error to the carriage movement is something like e = (d - d*cos(α)). And α can be computed as α = atan(x/d). Investigate function e(d) = d - d*cos(atan(x/d)). You want it to be zero. Clearly it happens when d→0 and when d→∞. Since d=0 does not make sense you want it to be as big as possible. Hence the motors are in the center.
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> Cerberus:
> The one think especially hard to understand is the
> use of the motors packed tightly together. Why? I
> always heard of skipping and heatissues. But why
> would you pack them together? (No rhetorics, I
> would really like an answer to that.
> Honestly.)(Maybe for heating the glass?)
I do not have Cerberus myself, but there is one obvious reason why to put motors as far away as possible from the pulley which turns the spectra line upward. It is to minimize nonlinearity between motor turn (in degrees) and carriage movement (in milimeters).
The point is that the line is being reeled on/off a drum which is on the corresponding motor shaft. This moves the point where the line touches on the drum vertically (up/down) from the center position on the drum. This movement changes the angle at wich the line bends around the pulley at the corresponding tower base. I do not know exactly how Cerberus is done but in a simplified situation lets mark the maximum angle between a horizontal plane and the line from the drum to the pulley as α, lets the distance from motor shaft to the pulley be marked as d, and lets the maximum (up/down) movement of the touch position (of the line on the drum) from the drum center be marked as x. Then x is a fixed constant (depends on the drum diameter, fishing line diameter and the cerberus height). The introduced error to the carriage movement is something like e = (d - d*cos(α)). And α can be computed as α = atan(x/d). Investigate function e(d) = d - d*cos(atan(x/d)). You want it to be zero. Clearly it happens when d→0 and when d→∞. Since d=0 does not make sense you want it to be as big as possible. Hence the motors are in the center.