Abstract: In a feedback control system with multivariable inputs and outputs, a network of plant actuators, each controlled by self-adaptive feedback control loops with pole-tracking zeroes, is provided as a plant or output load for a network of generally-conventional controllers. Each of the controllers sees a constant load, so the controller network can be viewed as having a constant gain-bandwidth characteristic transmission. The network of plant actuators cancels the effects the load inertias and its variations.

Abstract: Method and apparatus are provided for a Fly-By-Wire (FBW) Control System governing loop-gain (GH) for digital signal processing (DSP) compensation, and with analog compensation, both with and without pilot-input affects, so that aircraft FBW control provides high-fidelity pitch, roll, and yaw axis performance comparable to the 0% Step-Response-Overshoot (SRO) results achieved with open-loop pilot-input only, using conventional controls. The method and apparatus include true modeling of "active" pilot input, with frequency-domain transmission of time-delay times single pole response, as easily calibrated against a step disturbance to the loop-gain, GH, of interest. Both time-delay and single-pole response are given an operating range, applicable from very quick to relatively slow or tired pilots, where out-of-range pilot slowness eventually degrades the fidelity of the pitch, roll and yaw axis performance, albeit in a continuously predictable manner.

Abstract: A main feedback system regulates an output parameter of interest, such as velocity, versus a given range of load parameters, such as torque and inertia. An element feedback system rapidly adjusts an in-series-path zero to frequency track (cancel) a varying load-caused pole--including in-range variations of 100:1. Since zero-setting is inverse to an adjusted resistance required, a 100:1 zero range causes a highly non-linear resistance transmission, affecting the element loop's gain but not that of the main control feedback loop. By introducing a variable resistance of the same value as used in the main feedback system as a divider in the element feedback loop only, the element loop gain is made substantially constant over the entire pole-tracking range, and the element loop's bandwidth is made substantially constant over the same range, and thus rendering the dynamic response substantially constant over the same range.

Abstract: Method and apparatus for providing selfadaptive feedback control loop bandwidth and phase margin regulation automatically, to rapidly and predictably closely compensate for externally-caused bandwidth and phase margin changes, such as caused by changing load inertia presented to an actuator. Regulation is effected by controlling a loop-bandwidth correcting compensation element whose change is rendered equal to that of the loop affecting external change, but opposite in phase and change in magnitude. In a preferred embodiment, a correcting apparatus is within an internal feedback control loop which, by automatically compensating against a stated allowable range of uncorrected bandwidth variation, provides uniform static and dynamic bandwidth regulation for both internal feedback control loop and, therefore, regulation of the feedback control loop bandwidth and phase margin.

Abstract: A closed-loop feedback-controlled servo system is disclosed which reduces command-to-response error to the system's position feedback resolution least increment, .DELTA.S.sub.R, on a continuous real-time basis for all operating speeds. The servo system employs a second position feedback control loop on a by exception basis, when the command-to-response error .gtoreq..DELTA.S.sub.R, to produce precise position correction signals. When the command-to-response error is less than .DELTA.S.sub.R, control automatically reverts to conventional control means as the second position feedback control loop is disconnected, becoming transparent to conventional servo control means. By operating the second unique position feedback control loop used herein at the appropriate clocking rate, command-to-response error may be reduced to the position feedback resolution least increment. The present system may be utilized in combination with a tachometer loop for increased stability.

Abstract: A feedback loop control system is disclosed for controlling an element which has variable gain and which includes means for stabilizing the total loop gain and bandwidth of the control loop despite variations in the gain of the controlled element.

Abstract: Apparatus and a method are disclosed for continuously varying the output radiation frequency of a scanning laser system about a selected nominal output radiation frequency with a calibrated scan. Apparatus is disclosed for continuously varying the resonant frequencies of both the laser cavity and the reference cavity, for controlling this scanning and for calibrating the scan width. A method for calibrating the scan width is also disclosed.