Digital electronic foot control for medical apparatus and the like

Abstract

A digitial electronic foot pedal control system, especially for medical apparatus and the like having a plurality of operating functions which can be selected among, comprises a pivotally mounted pedal shaft and a foot-operated pedal fixed to the shaft to pivot therewith. Included are a shaft encoder connected to the shaft for producing a digital shaft position output signal indicative of pedal shaft position relative to a reference position and a plurality of address cards each having N addresses corresponding to N given shaft positions. Each address card corresponds to one or more medical apparatus functions and is selected when a corresponding function or functions are selected, each of the addresses on each address card corresponding to a particular shaft rotational position and each storing a given set of control output signals for operating the corresponding function or functions. A counter counts the shaft position output signal from the encoder; address pointers derived from the count are applied to the appropriate address card to thereby cause the outputting therefrom of the appropriate sets of control signals as the foot pedal shaft is rotated. A stepper motor is connected for driving the shaft in a rotational direction toward the shaft reference position when the shaft is displaced therefrom and when the stepper motor is energized by an appropriate control signal, thereby providing a resistance to, but not preventing, further pedal rotational movement away from the reference position so as to provide tactile information regarding pedal position and possible changes in apparatus function.