Machine speed controller

DETAILED DESCRIPTION The general object of the invention is to insure that a bar machine is shifted to feed speed exactly at the right point in an operating cycle.
A more specific object of the invention is to insure that feed speed is attained precisely at the low point in a bar machine despite variable performance of the machine elements.
Another object of the invention is to provide electronic control of the angle at which the speed command is generated based on the point where feed speed is attained in the preceding cycle.
To initiate a scheduled speed change at the correct point in the operating cycle of the machine, a speed change command is subjected to a variable delay which depends on how early in the preceding cycle the machine achieved the commanded speed level in response to the speed command.
Attaining the commanded speed level too early or too late in the previous cycle results in the speed command being correspondingly delayed or advanced.
A differential amplifier compares a current speed signal to a prior cycle speed signal representing the speed level actually attained in response to the speed command in the previous cycle.
The output of the differential amplifier is sampled at the design point at which the commanded speed level is to be achieved.
The sampled output is held as a decrease signal.
If the differential amplifier output reaches zero too early, the prior cycle speed signal is integrated from the zero point until the design point to produce an increase signal.
An up/down counter or equivalent stores a particular count which presets a second counter.
The second counter is started by an early speed change command signal and after counting the stored number, the second counter issues an output signal which represents the properly delayed speed change command.
The up/down counter is incremented or decremented once per cycle according to the increase or decrease signal.
If the machine attains the commanded speed level at the design point, no change is made in the stored count