摘要 |
A controller (FIGS. 1, 2) is provided in a dual servo system that drives a controlled element (22) with mechanically coupled first and second servos (24 and 44). This controller has a first (10, 110, 112) and second (14, 108, 114) digital process subsystem. The first digital processing subsystem can simultaneously drive the first and second servos. This first processing subsystem is operable to measure the responsiveness of the servos to the first processing subsystem and provide a self-checking indication. The second digital processing subsystem measures the responsiveness of these servos to the first digital processing subsystem and can provide an independent indication of failure. The foregoing can be extended to multiple channels for controlling independent multiple elements such as aircraft control surfaces. Preferably, two different types of computers (10, 14; 108, 110, 112, 114) with different programs can be employed to control three control channels. Since the system can provide self-checking and independent checking of its operation, the likelihood of "multi-axis hardover" is reduced.
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