Abstract: Control parameters such as an acceleration/deceleration time constant Tf, a position loop gain Kpf, a velocity loop proportional gain Pvf, and a velocity loop integral gain Ivf, each including respective values assigned to each of a plurality of different inertia values J0˜Jmax, are changed based on an inertia value Jx calculated by an inertia identifying unit and an adjusted control parameter calculated by an automatic control-parameter adjustment unit.

Abstract: An acceleration command calculator calculates an acceleration command “as” based on an output torque Tmb of the spindle motor applied when the rotational speed is less than or equal to a base rotational speed and an inertia Jm+Jl of the overall spindle. A switching speed calculator calculates a control mode switching speed Vs based on the acceleration command “as”. A control mode switching switch switches from a speed control mode to a position control mode when the motor speed Vm becomes less than or equal to the control mode switching speed Vs, to stop the spindle at a desired rotational position. The control mode switching speed Vs may be a value calculated using the following equation: Vs=60×(amax×0.5)1/2, where a maximum acceleration that can be achieved at this time is represented by a max.

Abstract: Control parameters such as an acceleration/deceleration time constant Tf, a position loop gain Kpf, a velocity loop proportional gain Pvf, and a velocity loop integral gain Ivf, each including respective values assigned to each of a plurality of different inertia values J0˜Jmax, are changed based on an inertia value Jx calculated by an inertia identifying unit and an adjusted control parameter calculated by an automatic control-parameter adjustment unit.

Abstract: A machine tool includes a main axis 30 to which a touch probe 17 is attached, a motor 15 that rotationally drives the main axis 30, a rotation angle position detector 16 that detects a rotation angle position of the motor 15, and a control device 20. The control device, when a measurement mode command for performing measurement of a workpiece by the touch probe 17 is input, multiplies a d-axis current command value Idc by a d-axis current correction coefficient K that is less than 1 to reduce the d-axis current command value Idc to a d-axis current command correction value Idc?, using a d-axis current command correction section 4. Thus, in the machine tool, small rotation vibrations of the main axis, generated when rotating the main axis to which the probe is attached and performing measurements of a workpiece, can be suppressed to thereby increase the measurement accuracy.

Abstract: An acceleration command calculator 22 calculates an acceleration command “as” based on an output torque Tmb of the spindle motor applied when the rotational speed is less than or equal to a base rotational speed and an inertia Jm+Jl of the overall spindle. A switching speed calculator 23 calculates a control mode switching speed Vs based on the acceleration command “as”. A control mode switching switch 5 switches from a speed control mode to a position control mode when the motor speed Vm becomes less than or equal to the control mode switching speed Vs, to stop the spindle at a desired rotational position. The control mode switching speed Vs may be a value calculated using the following equation: Vs=60×(amax×0.5)1/2, where a maximum acceleration that can be achieved at this time is represented by a max.

Abstract: A position control device for suppressing occurrence of stick-slip during a feed operation performed in a very low speed region is provided. Adders add an output obtained by multiplying actual speed deviation by a proportional gain, an integral component of actual speed deviation obtained by inputting actual speed deviation to an integral compensator, an output obtained by multiplying motor speed deviation by a proportional gain, and an integral component of the motor speed deviation obtained by inputting motor speed deviation to an integral compensator. The result is output as a torque feedback command. Each integral compensator has a coefficient changer capable of changing a coefficient from 0 to 1 to adjust integral gains in accordance with a speed feedforward command or a speed command. Large integral gain increases the response speed of switching from static to kinetic friction torque in a very low speed region thereby suppressing occurrence of stick-slip.

Abstract: A motor controller drives and controls a motor to drive a shaft subject to gravity. The motor controller includes a PI control unit which controls the velocity of the motor, a brake which prevents the falling of the shaft in accordance with a brake signal, and a storage unit which detects the brake signal input to the brake. On the basis of the state of the detected brake signal, the storage unit stores the torque command value when the brake signal has changed from off to on, and sets the stored torque command value to an integral component of the PI control unit when the brake signal has changed from on to off.

Abstract: For full-closed position control, there is provided a position control device capable of suppressing occurrence of stick-slip which occurs during a feed operation performed in a very low speed region. An adder 5 and an adder 24 add an output obtained by multiplying an actual speed deviation El by a proportional gain Pl, an integral component Tl of the actual speed deviation which is obtained by inputting the actual speed deviation El to an integral compensator 25, an output obtained by multiplying a motor speed deviation Em by a proportional gain Pm, and an integral component Tim of the motor speed deviation which is obtained by inputting the motor speed deviation Em to an integral compensator 9, and the result is output as a torque feedback command Tfb.

Abstract: A motor controller is provided which has a function to prevent the falling of a shaft when the power supply to a motor is turned on. The motor controller includes a PI control unit 1 which controls the velocity of a motor 4; a brake 8 which prevents the falling of the shaft in accordance with a brake signal; and a storage unit 7 which detects the brake signal input to the brake 8, and on the basis of the state of the detected brake signal, stores a torque command value T* calculated by the PI control unit 1. The storage unit 7 stores the torque command value T* when the brake signal has changed from off to on, and the storage unit 7 sets the stored torque command value T* to an integral component of the PI control unit 1 when the brake signal has changed from on to off. Thus, the falling of the shaft at the start of power application can be prevented.

Abstract: A synchronous motor control device having an optimal protection function in accordance with an operational state of a motor is provided.

Abstract: A deflection amount Ps representing a difference between a position detection value Pl of a driven body and a position detection value Pm of a motor is detected. A position calculator proportional constant Kp, a time constant Tp of a first-order lag circuit that inputs a the deflection amount Ps, and a time constant Tv of a first-order lag circuit that inputs a difference between a speed detection value Vl of the driven body and a speed detection value Vm of the motor are changed based on the deflection amount Ps.

Abstract: A synchronous motor control device having an optimal protection function in accordance with an operational state of a motor is provided.

Abstract: A deflection amount Ps representing a difference between a position detection value Pl of a driven body and a position detection value Pm of a motor is detected. A position calculator proportional constant Kp, a time constant Tp of a first-order lag circuit that inputs a the deflection amount Ps, and a time constant Tv of a first-order lag circuit that inputs a difference between a speed detection value Vl of the driven body and a speed detection value Vm of the motor are changed based on the deflection amount Ps.

Abstract: A position controller for controlling a position of a feed shaft of a machine having a motor and the feed shaft driven by the motor is provided. A subtractor calculates a difference between a speed instruction and a speed detection value of a motor and outputs as a speed difference. An adder 20 adds the speed difference and a speed instruction compensation value and a speed difference proportion calculator calculates a proportional component of the speed difference based on the added result and a proportional gain. A speed difference integral calculator calculates an integral component of the speed difference based on the speed difference and an integral gain. An adder 6 adds the proportional component of the speed difference and the integral component of the speed difference to output a torque instruction.

Abstract: A position controller for controlling a position of a feed shaft of a machine having a motor and the feed shaft driven by the motor is provided. A subtractor calculates a difference between a speed instruction and a speed detection value of a motor and outputs as a speed difference. An adder 20 adds the speed difference and a speed instruction compensation value and a speed difference proportion calculator calculates a proportional component of the speed difference based on the added result and a proportional gain. A speed difference integral calculator calculates an integral component of the speed difference based on the speed difference and an integral gain. An adder 6 adds the proportional component of the speed difference and the integral component of the speed difference to output a torque instruction.

Abstract: A current detecting circuit (19) detects an output voltage of an inverter, a voltage error computing unit (21) computes an voltage error between the output voltage and a voltage command value, a deadtime compensation amount storage unit (18) stores a relationship between the voltage error, and an output current value detected by a current detecting circuit (20). A deadtime compensation computing unit (17) computes a deadtime compensation amount from the deadtime compensation amount storage unit (18) according to a current command value, and an adder (16) adds the deadtime compensation amount and the voltage command value so as to obtain the added correcting voltage command value. The operation of the inverter is controlled on the basis of the computed correcting voltage command value which enables inverter control devices to accurately control output current due by accurate correction of the output voltage.