| 摘要 |
Apparatus, for use in a servo-control system and which provides a smooth "bumpless" transition while switching from one transducer feedback signal to another, is described. Specifically, with this apparatus, a plurality of tracking signals are first produced in which each signal has a value which, in response to the value of a corresponding select signal, either tracks the feedback signal produced by a corresponding one of a plurality of transducers or remains constant. Each of these tracking signals is then subtractively summed with the feedback signal produced by the corresponding transducer in order to produce an output signal. Each of the output signals is then fed-back and subtractively summed with a command signal and the resulting difference, in turn, is applied as an error signal to a servo-amplifier. The values of all the select signals are set, by illustratively a process computer, in accordance with the particular transducers being switched. Since values of all the fed-back output signals are equal to zero, at the instant any transducer is switched, a "bumpless" transition advantageously results regardless of which transducer is switched, when it is switched and any difference occurring between the values of the feedback signals of the transducers being switched.
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