N-phase stepping motor which is driven by ultra-micro-step driving method and the method of driving the N-phase stepping motor, as well as ultra-precision measurement equipment and ultra-precision machining equipment equipped with the same stepping motor

摘要

PROBLEM TO BE SOLVED: To provide an ultra-microstep driving method wherein the resolution of an N-phase stepping motor that is rotated at ultra-low speed or at constant speed is dramatically enhanced just by modifying a logic circuit with a conventional electronic circuit used without modification and further a grating audible sound produced when the rotation of the stepping motor is started and it is held becomes less annoying.;SOLUTION: The basic step angle of the N-phase stepping motor is divided into n to obtain minute step angles /n. Each minute step angle is further divided by a division number m that is an integer not less than 2 with which the motor can be driven by external command pulses. Further, at least two or more excitation patterns in an excitation period T are sequentially changed with predetermined regularity at each of m times of input of external command pulses. A resultant torque vector required for stepping by a minute step angle " equivalent to /(nm) is thereby generated. Further, every m times, the resultant torque vectors are combined to generate a resultant torque vector required for stepping by a minute step angle ' equivalent to /n.;COPYRIGHT: (C)2008,JPO&INPIT