Control system for use in control of loops with dead time

Claim 1

IN A CONTROL SYSTEM OF THE TYPE WHICH FOLLOWS AN INPUT, A CONTROL LOOP HAVING A TRANSFER FUNCTION WHICH INCLUDES DEAD TIME, THE CONTROL LOOP INCLUDING OPERATING MEANS WHICH CONTINUOUSLY PERFORMS AN OPERATION ON A MEDIUM, THE OPERATION BEING SUBJECT TO CONTROL WHEREBY A DETECTABLE CHARACTERISTIC OF THE MEDIUM IS THEREBY VARIED IN ACCORDANCE WITH THE INPUT, MEANS RESPONSIVE TO VARIATIONS IN THE SAID CHARACTERISTIC OF THE MEDIUM TO PROVIDE A CONTROLLING RESPONSE, THERE BEING A DEAD TIME BETWEEN SAID RESPONSE AND THE OPERATIONAL CONTROL EFFECTING THE SAME, A CONTROLLER FOR CONTROLLING SAID OPERATION IN ACCORDANCE WITH SAID CONTROLLING RESPONSE WHEREBY THE SYSTEM TENDS TO MAINTAIN SAID CHARACTERISTIC SUBSTANTIALLY CONSTANT RELATIVE TO THE INPUT, AND AN ADDITIONAL CONTROL LOOP, THE ADDITIONAL CONTROL LOOP INCLUDING A FUNCTION GENERATOR, SAID FUNCTION GENERATOR BEING RESPONSIVE TO THE OUTPUT OF THE CONTROLLER, THE OUTPUT OF THE FUNCTION GENERATOR PROVIDING AN ADDITIONAL CONTROLLING RESPONSE WHICH IS COMBINED WITH THE INPUT TO THE CONTROLLER, SAID ADDITIONAL CONTROLLING RESPONSE BEING SUBSTANTIALLY EQUAL TO THE DIFFERENCE BETWEEN A PREDICTION OF THE VALUE OF THE CONTROLLING RESPONSE WITH THE DEAD TIME REMOVED AND A PREDICTION OF THE VALUE OF THE CONTROLLING RESPONSE WITH THE DEAD TIME RETAINED.