Digital servo system

Claim 1

A CONTROL SYSTEM FOR USE IN CONJUNCTION WITH A DIGITAL COMPUTER WHICH RECEIVES INFORMATION RELATIVE TO THE SUCCESSIVE POSITIONS OF AN ANALOG DEVICE WHOSE POSITION IS TO BE CONTROLLED BY SAID CONTROL SYSTEM, SAID COMPUTER ALSO RECEIVING SUFFICIENT INFORMATION TO ENABLE IT TO CALCULATE SUCCESSIVE DESIRED POSITIONS FOR SAID ANALOG DEVICE, SAID COMPUTER SUPPLYING AT THE END OF EACH CALCULATION CYCLE FIRST AND SECOND DATA, SAID FIRST DATA BEING INDICATIVE OF THE PRESENT POSITION ERROR OF SAID ANALOG DEVICE FROM A CALCULATED DESIRED POSITION, SAID SECOND DATA BEING INDICATIVE OF THE EXPECTED CHANGE FROM THE PRESENT DESIRED POSITION TO THE NEXT DESIRED, POSITION; SAID CONTROL SYSTEM COMPRISING A STORAGE DEVICE, MEANS ADAPTED TO RECEIVE SAID FIRST DATA AND MANIFEST A REPRESENTATION OF SAID FIRST DATA IN SAID STORAGE DEVICE, MEANS RESPONSIVE TO THE VALUE OF THE REPRESENTATION IN SAID STORAGE DEVICE FOR POSITIONING SAID ANALOG DEVICE IN ACCORDANCE THEREWITH, MEANS CONNECTED TO SAID ANALOG DEVICE FOR PRODUCING SIGNALS REPRESENTING UNIT CHANGES IN POSITION OF SAID ANALOG DEVICE, THE LAST-MENTIONED SIGNALS BEING SUPPLIED TO SAID STORAGE DEVICE FOR MODIFYING THE REPRESENTATION IN SAID STORAGE DEVICE AS A FUNCTION OF CHANGE IN UNIT POSITION OF SAID ANALOG DEVICE, AND MEANS ADAPTED TO RECEIVE SAID SECOND DATA AND RESPONSIVE THERETO FOR FURTHER MODIFYING SAID REPRESENTATION IN SAID STORAGE DEVICE AT A SUBSTANTIALLY CONSTANT RATE DURING EACH CALCULATION CYCLE OF SAID COMPUTER, SAID RATE BEING A FUNCTION OF THE VALUE OF SAID SECOND DATA.