| 摘要 |
A digital servovalve control system employs a stepper motor to rotate the input shaft of a servovalve. The servovalve has no feedback shaft; feedback in the control system is provided exclusively by a digital encoder connected to the load output to indicate changes in its position. The encoder output is compared with a command signal in a digital controller circuit that generates and transmits pulses to the stepper motor in response to the difference between the command and feedback signals. The control system includes means for keeping track of the null position of the servovalve so that the digital controller can always accurately respond to the signals it receives. The servovalve used with the control system includes a valve spool that rotates with rotation of the input shaft, thereby providing a wiping action only afforded in the prior art by rotation of a feedback shaft.
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