Fanuc Corporation

Takahiro Akiyama

Yasusuke Iwashita

Masakazu Niwa

Tadashi Okita

Shinichi Kono

Tomohisa Tsutsumi

Geng Li

Junichi Tezuka

Yuuki Morita

A sensorless induction motor control device with a function of correcting a slip frequency wherein a slip frequency estimation unit estimates the slip frequency from at least one kind of current flowing through the motor. A voltage command value calculation unit calculates a D-phase voltage command value and a Q-phase voltage command value which are used for controlling a voltage applied to the motor using a Q-phase current command value calculated based on a difference between a speed estimation value, which is calculated using an estimation value of the slip frequency, and an externally supplied speed command value. An ideal voltage command value determination unit determines an ideal voltage command value using the speed command value and the Q-phase current command value. An actual voltage command value calculation unit calculates an actual voltage command value using the D-phase voltage command value and the Q-phase voltage command value. and A slip frequency correction unit compares the ideal voltage command value with the actual voltage command value and changes the estimation value of the slip frequency to make it smaller if the actual voltage command value is smaller than the ideal voltage command value.

Sensorless induction motor control device having function of correcting slip frequency of motor

The controller controls a spindle connected to an induction motor via a belt by controlling the rotational velocity of the induction motor. The spindle has an encoder attached thereto for detecting the position of the spindle, but the induction motor does not have a velocity detector attached thereto. The velocity of the induction motor is estimated from the spindle velocity obtained from output of the encoder, and slip of the belt is detected based on the estimated velocity of the induction motor. When occurrence of slip of the belt is detected, the estimated velocity of the induction motor will not be used for the control of the induction motor.

Controller of spindle provided with encoder

An excitation current processor of a current controller processes the excitation current corresponding to the magnetic flux instruction from the magnetic flux instruction processor. It multiplies this excitation current with a boost coefficient to obtain an excitation current instruction. Here, the boost coefficient is determined based on the difference obtained by subtracting the magnetic flux estimation value processed by the magnetic flux processor based on the excitation current feedback from the voltage conversion device from the magnetic flux instruction input from the magnetic flux instruction processor. Further, the boost coefficient can be found from the function of time from the start of the rise of the magnetic flux.

Electric motor control device

A motor control apparatus for computing or outputting motor load information, comprises: a storage unit which stores a function or table obtained in advance based on parameters used for the computation of the load information and on an actually measured value of a motor output or motor torque; and a load meter computing unit which computes the load information from the function or table stored in the storage unit by using the parameters used for the computation of the load information. With the above configuration, the load meter is computed in such a manner as to accurately indicate the load condition of a motor in real time over the entire speed range of the motor including the nonlinear control region of the motor, and the motor is controlled using the thus computed value or the computed value is displayed on a display unit.

Motor control apparatus

A fixed-position stop control apparatus () includes: a move-instruction generating means () for generating a move instruction for each control cycle; a position loop control means () for position controlling a rotation shaft () for each control cycle according to the move instruction generated by the move-instruction generating means; and a speed loop control means () for speed controlling the rotation shaft according to one of a speed instruction generated by a higher level control apparatus () and a predetermined speed instruction, thereby switching the speed control of the rotation shaft by the speed loop control means to the position control of the rotation shaft by the position loop control means. In this fixed-position stop control apparatus, the move instruction generated by the move-instruction generating means has acceleration smaller than the acceleration corresponding to the acceleration and deceleration ability of the rotation shaft. With this arrangement, time required for the rotation shaft to stop at a fixed position can be decreased.

Fixed-position stop control apparatus for rotation shaft

A servo control device that displays, by a two-dimensional image, evaluation of control precision of a servo system, includes: an instruction unit that instructs a position instruction having periodicity; a unit that records a track of position data based on a position feedback of a servo system according to the position instruction; and a first drawing unit that draws position data based on the position feedback, data before a quarter cycle or after a quarter cycle of the position data or position data based on the position instruction before a quarter cycle or after a quarter cycle, on a two-dimensional plane including orthogonal two axes, as the axis data of the orthogonal two axes respectively.

Servo control device and method of adjusting servo system

A controller for a vector control of an induction motor, which is capable of easily determining a rotor resistance for use in calculation of a slip frequency. A temperature sensor is provided for detecting a temperature of a stator. Information on relation between the rotor temperature and the rotor resistance predetermined based on measurement is stored in a table. In driving the induction motor, the rotor resistance for the stator temperature detected by the temperature sensor is read from the table. A torque command Iis divided by a magnetic flux command &#x3a6;and the obtained quotient is multiplied by the read value of the rotor resistance to obtain the slip frequency &#x3c9;s, so that the vector control is performed based on the obtained slip frequency &#x3c9;s. The value of the rotor resistance is easily determined by simply referring the table without complicated calculation. Since the stored information on the rotor resistance are based on measured values, a more precise value of the slip frequency is obtained to realize a precise vector control of the induction motor.

Controller for induction motor

A motor controller capable of obtaining information on offsets, amplitudes and a phase difference of analog feedback signals from encoders without using special measuring device. The analog feedback signals from the encoders are A/D converted and the offsets, the amplitudes and the phase difference of A-phase and B-phase analog feedback signals are obtained based on the converted digital signals by an arithmetic section. The obtained offsets, amplitudes and phase difference are displayed by a display section of the motor controller and/or a display section of a numerical controller as a host controller. Further, the obtained offsets and amplitudes are compared with respective reference values for determining acceptability of the feedback signals from the encoders and the results of the comparison is displayed by the display section and/or the display section of the numerical controller.

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Yamanashi, Japan

Takahiro Akiyama