Abstract: A drive control method for a variable reluctance type motor capable of improving the motor efficiency by preventing generation of a disturbance torque. In function generators (8A to 8C) of a controller for embodying the method, the motor rotation direction and the motor driving mode are determined based on the generation order of A- and B-phase feedback pulses from a pulse coder (7) and the sign of a torque command (Tc) from a speed loop compensation circuit (1), and, on the basis of the determination results, either one of four excitation patterns is selected. Function signal values corresponding to actual motor electrical angles (.theta.) are generated from the function generators in accordance with the selected excitation pattern, and excitation of individual phases of the motor (6) is controlled by power amplifiers (4A to 4C) which respond to voltage commands derived based on these function signal values.

Abstract: In an optical rotary encoder which detects the angle of rotation of a rotary shaft by detecting the ray of light transmitting through an angle detection pattern formed on a rotary disc coupled to the rotary shaft, a deflection detection pattern (20b) is disposed on the rotary disc separately from the angle detection pattern and the direction and magnitude of deflection of the rotary shaft with respect to the center of a bearing is detected by detecting the change in the quantity of light passing through the deflection detection pattern (20b). The angle of rotation thus detected is corrected to the angle of rotation around the axis of the rotary shaft.

Abstract: An electric servo system has an electrical drive and a controllable object driven by the electrical drive whereby an error between an actual amount of actuation of the controllable object and a target value toward which the object is controlled is applied to the electrical drive to control the same so that the amount of actuation of the controllable object coincides with the target value. A compensator is provided on the input side of the electrical drive, for compensating the load characteristics of the controllable object such that the output of the electrical drive does not have apparent dependency on torque of the load.

Abstract: A positioning control system which has a servo system provided with a position feedback system for detected positional information and a velocity feedback system for detected velocity information of a motor and in which the motor is driven by the servo system in accordance with commanded positional information to position a movable machine part of a numerical-controlled machine. The disparity between the detected velocity of the movable machine part and the detected motor velocity is fed back to the control input side of the motor, thereby suppressing vibration of the movable machine part at the moment of completion of the positioning operation.