Guidance controller for a minimal discrete command set

A beam rider guidance system for directing a steerable object, such as a torpedo, using a limited set of discrete guidance commands. The guidance system senses a guidance point distance representing the guidance point position relative to a bearing line to a target and the rate of change of distance between the bearing line and the torpedo. Two corresponding input functions are classified into first and second sensed linguistic variables based upon membership functions from first and second different sensed variable membership function sets to become fuzzy inputs that produce fuzzy output control membership functions from a control output membership function set based upon the logical manipulation of the fuzzy inputs. These fuzzy output functions are in the form of spikes and are converted into one of a plurality of predetermined discrete commands. A tactical limiter unit selectively defines a series of situations in which commands are allowed or not allowed to reach the torpedo.