Abstract: A servo controller capable of controlling motors to be driven in different control modes, such as a synchronous motor and an induction motor, irrespectively of the type of the motor, and also capable of carrying out servo control by using incremental feedback signals. A control section common to individual motors and a control section dedicated to each motor are provided in a servo controller. The common control section is always used, while the dedicated control section is selectively used in accordance with the motor to be driven. Thereby, motors each requiring a different control mode can be controlled by the servo controller of one type. The use of th servo controller of one type can reduce maintenance management and a load on a CNC. Also, the provision of the control section common to individual motors can restrain increases of size, installation area and manufacturing cost of the device.

Abstract: A method of and an apparatus for controlling a plurality of servomotors, in which one driven body is driven by one main servomotor and at least one subordinate servomotor. Synchronous control is performed with good response and high accuracy and repetitive control is performed with simple arrangement preventing interference between axes, and further operation mode of the plurality of servomotors is easily switched between coupled driving and independent driving. A plurality of servomotors comprises one main servomotor and at least one other servomotor subordinate to the main servomotor, and position control is performed on the main servomotor side while velocity control and current control are performed individually for each servomotor. A velocity command for the main servomotor is subjected to a position adjustment based on a position deviation between the main servomotor and subordinate servomotor and the adjusted velocity command is used for the subordinate servomotor.

Abstract: A predictive repetition control method for a servo motor and an apparatus therefor, which can converge a positional deviation relative to a command, repeated at intervals of a predetermined period, to zero even if the command contains an asynchronous component which is not synchronous with the predetermined period. A repetitive controller 5 and an invert system feedforward controller 6 for a control object 4 are arranged in parallel in a servo control system of the servo motor. The feedforward controller 6, including a FIR digital filter, receives a future command P whose degree of advancement corresponds to an order N of the control target. Coefficients of the filter are automatically determined based on the command P to be inputted and a positional deviation .epsilon. so that the feedforward controller 6 itself functions as an invert system. A transfer function of the feedforward controller 6 functions as a reciprocal of a transfer function of the control object, and hence a transfer function of an output .

Abstract: An interface system for a servo controller has a speed controller (7), a current controller (9), etc., which have heretofore been disposed on the side of a servomotor, disposed in a control circuit (15) on the side of an NC apparatus. The present position and speed data from the servomotor are fed back and are stored in a common RAM, and control signals for a driver circuit, such as an inverter (12), are supplied from the NC apparatus side to the servomotor side. A system bus on the NC apparatus side is directly connected to a local bus on the servomotor side.

Abstract: A velocity control system in which, when an observer is used to estimate velocity based on position information from a rotary encoder, load torque, which is a cause of a steady-state estimation error, is estimated at the same time and velocity is controlled by using the estimated value. Velocity control of the motor is executed by feeding back the position information from the rotary encoder to an integration element in the I-P controller.

Abstract: In reference point return control, a grid point position at which a one-revolution signal (RTS) is first generated by a rotary encoder (24) following restoration of a deceleration limit switch (29) is adopted as a reference point. When a zero point return mode (ZRN="1") for returning a movable element to the reference point is in effect, a numerical controller (21) regards the position at which the one-revolution signal (RTS) is generated by the rotary encoder (24) as being zero. A commanded position REF.sub.n, until the next one-revolution signal is generated, is monitored at every predetermined time, such monitoring of the commanded position being repeated until the movable element arrives in the vicinity of the reference point. When the movable element approaches the reference point and the deceleration limit switch (29) is restored, the commanded position REF.sub.n at an initial time every .sub..DELTA. T is obtained, a distance (N-REF.sub.

Abstract: A servomotor velocity control system has an estimating unit (4) for obtaining an estimated value (V) of velocity based on rotary encoder position information (.theta.), which includes a current (I.sub.L) indicative of load torque, and motor current (I) of a servomotor (5). The system is adapted to obtain a torque command signal (U) based on the estimated value (V) of velocity and a velocity comman signal (V.sub.c).

Abstract: A servomotor velocity control system according to the present invention control velocity by using an observer for obtaining a sensed value of velocity while estimating motor load torque. When resolution of a rotary encoder is a problem in a region of low motor velocities, this is compensated for to improve the velocity sensing precision in the low-velocity region. In a region of high motor velocities, velocity processing is executed based on the output of the rotary encoder considering the processing time of a CPU. Use or non-use of the observer for obtaining the estimated value of velocity is selected in dependence upon the velocity of the motor.