US 5,671,138 A · Fuzzy controller for acoustic vehicle target intercept guidance

Abstract

A target intercept guidance system for directing a steerable object, such a torpedo with an acoustic homing device. The guidance system senses the bearing and range between a first site and a second site and determines the position of a guidance point for the steerable object as it moves toward the second site. Two error functions are produced. The first error function represents the angle between the bearing from the guidance point of the steerable object to the second site and the course of the steerable object. The second error signal represents an estimate of the rate of change of that angle. These error signals are classified into first and second sensed linguistic variables based upon membership functions from the first and second sensed variable membership function sets to become fuzzy inputs that produce fuzzy outputs comprised of control output linguistic variables and corresponding control output membership functions from a control output membership function set based upon logical manipulation of the fuzzy inputs. These fuzzy control output membership functions are converted into an output having an appropriate form for control after being conditioned in response to other information including the relative positions of the guidance point of the steerable object and the second site.

Claims11

Dependent claims

A system for guiding a steerable object from a first site toward a second site wherein the steerable object includes an acoustic homing device characterized by a center point and by defining a guidance point externally to the steerable object and leading the steerable object as it moves toward the second site, said system comprising:

sensing means for generating bearing and range signals representing the bearing and range from the first site to the second site;
model means for generating signals representing the bearing from the guidance point of the steerable object to the second site and course, speed and position of the steerable object;
error signal generating means response to the signals from said sensing means and said model means for generating a first sensed variable signal based upon the bearing from the guidance point of the steerable object to the second site and the course of the steerable object and a second sensed variable signal based upon the rate of change of the first sensed variable signal;
fuzzy control means responsive to said first and second sensed variable signals for generating a guidance command for controlling the steerable object in response to a plurality of logical rules;
conditioning means for conditioning the guidance command in response to a selected one of said signals generated by the model means;
and
means for transferring the conditioned guidance command to the steerable object.

4 more elements

An iterative method for guiding a steerable object from a first site to a second site wherein the steerable object includes an acoustic homing device characterized by a center point and by a guidance point externally to the steerable object and leading the steerable object as it moves toward the second site, said method comprising, during each iteration, the steps of:

determining parameters corresponding to the range and bearing from the first site to the second site and corresponding to the bearing from the guidance point of the steerable object to the second site and to the course, speed and position of the steerable object;
generating a first sensed variable signal based upon the bearing from the guidance point of the steerable object to the second site and the course of the steerable object and a second sensed variable signal representing the rate of change of the first sensed variable signal;
generating in a fuzzy controller a guidance command for controlling the steerable object according to a plurality of logical rules in response to the first and second sensed variable signals;
conditioning the guidance command in response to a selected one of said parameters;
and
transferring the conditioned guidance command from the fuzzy controller to the steerable object.

3 more elements

Dependencies are inferred from the claim text.

Fuzzy controller for acoustic vehicle target intercept guidance

Life of this patent

Fuzzy controller for acoustic vehicle target intercept guidance

Life of this patent

Abstract

Claims11