Abstract STABILITY OF A SAMPLED-DATA FEEDBACK CONTROL SYSTEM FOR AN AIRFRAME IS ENHANCED BY VARYING THE SAMPLING INTERVAL AS A FUNCTION OF THE PARTICULAR BENDING MODE THE AIRFRAME EXHIBITS. A command signal is fed to the control system for controlling the state of the airframe; and sensed signals are generated by transducers on the airframe representative of the actual state of the airframe. The difference between the command signal and the sensed signals is sampled thereby generating a train of error pulses. The train of error pulses is then fed into a digital controller for computing digital signals for controlling the airframe according to its characteristics. A signal is generated for identifying the instantaneous body bending mode frequency; and the sampling interval of the error signal is varied inversely with respect to the instantaneous body bending frequency to maintain the product of the mode frequency and sampling interval a constant.
A method for controlling an air frame having input command signal for controlling the state of said air frame and output sensed signals representative of the actual state of said air frame, comprising: sampling the difference between desired command and sensed output signals thereby generating a train of pulses representative of the error between the same; generating from said error signal a train of pulses for controlling said air frame in a predetermined manner; generating an identification signal representative of an instantaneous body bending mode frequency of said air frame; and varying the sampling interval of said error signal inversely with respect to the instantaneous body bending frequency whereby as the instantaneous frequency of said body bending increases the sampling interval decreases to maintain system stability.
Claim 2
Independent Claim
126 words
A method for controlling an air frame having input command signal for controlling the state of said air frame and output sensed signals representative of the actual state of said air frame, comprising: sampling the difference between desired command and sensed output signals thereby generating a train of pulses representative of the error between the same; generating from said error signal a train of pulses for controlling said air frame in a predetermined manner; generating an identification signal representative of an instantaneous body bending mode frequency of said air frame; and varying the sampling interval of said error signal inversely with respect to the instantaneous body bending frequency whereby as the instantaneous frequency of said body bending increases the sampling interval decreases to maintain system stability.
Claim 3
Dependent Claim
23 words
The method of claim 1 characterized by the fact that the product of the sampling interval and instantaneous body bending frequency remain constant.
Claim 4
Dependent Claim
63 words
In a sampled-data feedback control system for controlling the dynamics of an air frame, the improvement comprising: means sensing the condition of a state of said air frame for generating a signal representative thereof; and means receiving said state signal for varying the sampling interval of said system as an inverse function of the instantaneous frequency of oscillation determined by said sensing means.
Claim 5
Dependent Claim
63 words
In a sampled-data feedback control system for controlling the dynamics of an air frame, the improvement comprising: means sensing the condition of a state of said air frame for generating a signal representative thereof; and means receiving said state signal for varying the sampling interval of said system as an inverse function of the instantaneous frequency of oscillation determined by said sensing means.