A numerical controller includes: a vibration amplitude specifying unit for specifying an amplitude of a vibration component generated by a blade of a tool being brought into contact with a workpiece at a predetermined cycle, due to rotation of a spindle out of a spindle load; a gain calculating unit for calculating a gain of PID control such that an output of the feed speed is uninfluenced by the amplitude, based on the amplitude of the vibration component specified by the vibration amplitude specifying unit; and a speed control unit for outputting a feed speed of the spindle controlled by the PID control, by using the gain calculated by the gain calculating unit.

A servomotor control device includes: a servomotor; a driven body that is driven by the servomotor; a connection mechanism that connects the servomotor and the driven body; a first position detection section that detects a position of the servomotor; a second position detection section that detects a position of the driven body; and a motor control unit, in which the motor control unit includes: a force estimation section that estimates a drive force acting on the driven body at a connection part between the connection mechanism and the driven body; a rigidity estimation section that estimates a magnitude of rigidity of the connection mechanism based on a detected position of the servomotor, a detected position of the driven body, and an estimated drive force; and a rigidity variation detection section that detects a change in rigidity of the connection mechanism, based on the estimated magnitude of rigidity.

A motor controller which controls a servo motor for driving a machine, includes: a speed command unit which commands the speed of the machine; a speed detection unit which detects the speed of the servo motor; and a speed control unit which produces a torque command based on a speed command and a motor speed detected so as to control the speed of the servo motor, where the speed control unit includes a filter which approximates the inverse characteristic of a transmission characteristic from the servo motor to the machine, the filter has a transmission characteristic F(s) based on a frequency , a vibration damping coefficient and a cutoff frequency .sub.adj which are adjustment parameters and the frequency is adjusted so as to be equal to or more than an antiresonant frequency .sub.0 of the machine but less than a resonant frequency .sub.p.

A servo control system includes a position command generator, a position detector for a feed axis, a positional deviation obtainer for calculating a positional deviation, a position control loop, a band limiting filter for attenuating a high frequency component of the positional deviation, a dynamic characteristic compensation element for advancing a phase, a learning controller including the band limiting filter and the dynamic characteristic compensation element, a sine wave sweep input unit for applying a sine wave sweep to the position control loop, a frequency characteristic calculator for estimating the gain and phase of position control loop input and output signals, and a learning control characteristic evaluation function calculator for calculating an evaluation function, which indicates a position control characteristic with the learning controller based on a frequency characteristic by actual measurement and a frequency characteristic of the learning controller.

A motor controller which controls a servo motor for driving a machine, includes: a speed command unit which commands the speed of the machine; a speed detection unit which detects the speed of the servo motor; and a speed control unit which produces a torque command based on a speed command and a motor speed detected so as to control the speed of the servo motor, where the speed control unit includes a filter which approximates the inverse characteristic of a transmission characteristic from the servo motor to the machine, the filter has a transmission characteristic F(s) based on a frequency , a vibration damping coefficient and a cutoff frequency .sub.adj which are adjustment parameters and the frequency is adjusted so as to be equal to or more than an antiresonant frequency .sub.0 of the machine but less than a resonant frequency .sub.p.

A motor control device includes: a position command section configured to generate a position command for a control object; a position detecting section configured to detect a position of the control object or a position of a motor configured to drive the control object; and a position control section configured to control a position of the motor based on the position command and the detected position of the control object or the motor, in which at least one of the position command section and the position control section includes a vibration suppression filter configured to approximate a reverse characteristic of a vibration characteristic generated between the motor and the control object, and the vibration suppression filter changes a vibration suppression frequency according to at least one of the position and a mass of the control object.

A servomotor control device includes: a servomotor, detection unit, driven body, connection mechanism, and motor control unit, in which the motor control unit includes: a force estimation section that estimates a drive force acting on the driven body at a connection part between the connection mechanism and the driven body; a correction amount generation section that generates a correction amount for correcting the position command value, based on the drive force estimated and a constant for correction; and a rigidity estimation section that gradually increases the constant for correction in a state suspending generation of the position command value, and estimates a magnitude of rigidity of the connection mechanism based on the constant for correction when a variation point occurs in behavior of rotation position information of the servomotor detected, drive force estimated, or correction amount generated.

A servomotor control device includes: a servomotor; a driven body that is driven by the servomotor; a connection mechanism that connects the servomotor and the driven body; a first position detection section that detects a position of the servomotor; a second position detection section that detects a position of the driven body; and a motor control unit, in which the motor control unit includes: a force estimation section that estimates a drive force acting on the driven body at a connection part between the connection mechanism and the driven body; a rigidity estimation section that estimates a magnitude of rigidity of the connection mechanism based on a detected position of the servomotor, a detected position of the driven body, and an estimated drive force; and a rigidity variation detection section that detects a change in rigidity of the connection mechanism, based on the estimated magnitude of rigidity.

A servomotor control device includes: a servomotor, detection unit, driven body, connection mechanism, and motor control unit, in which the motor control unit includes: a force estimation section that estimates a drive force acting on the driven body at a connection part between the connection mechanism and the driven body; a correction amount generation section that generates a correction amount for correcting the position command value, based on the drive force estimated and a constant for correction; and a rigidity estimation section that gradually increases the constant for correction in a state suspending generation of the position command value, and estimates a magnitude of rigidity of the connection mechanism based on the constant for correction when a variation point occurs in behavior of rotation position information of the servomotor detected, drive force estimated, or correction amount generated.

A control device includes: a processor wherein the processor is configured to generate one or more second control signals obtained by reducing at least one frequency component from a first control signal, output one control signal among the first control signal and the one or more second control signals, receive an instruction indicating execution of a reduction in the frequency component, generate a driving signal for driving a robot based on the control signal output from the processor and output the driving signal, output the first control signal when a first condition including non-input of the instruction indicating the execution of the reduction in the frequency component is satisfied, and output the second control signal when a second condition including input of the instruction indicating the execution of the reduction in the frequency component is satisfied.