摘要:
Parameter set 1: T1a, T2a, Fa, Aa, parameter set 2: T1b, T2b, Fb, Ab, and parameter set 3: T1c, T2c, Fc, Ac, which consist of parameters having discrete values in three stages (large, medium and small) are prepared in the memory for example of the CNC 1 or the personal computer 3. For a given parameter set, the set giving priority to accuracy (S=0) is indicated by P (T1p, T2p, Fp, Ap), while the set giving priority to speed (S=1) is indicated by Q (T1q, T2q, Fq, Ag), and interpolation is performed and the parameter set Y=(1−S)×P+S×Q is obtained. The CNC 2 creates operating commands based on set Y and outputs these to the servo control section 2.
摘要:
A force control method for a bar feeder supporting a workpiece in a lathe, including seizing the workpiece by a Z-axis spindle of the lathe and the bar feeder, performing position control by the Z-axis spindle of the lathe, and performing force control by the bar feeder to apply a constant torque to the workpiece during the force control of the bar feeder supporting the workpiece in the lathe. This control of the bar feeder does not require the Z-axis spindle of the lathe and the bar feeder to be synchronized for the position control in the Z-axis direction, and prevents the workpiece from being deflected.
摘要:
A control method for an alternating current motor, wherein after a torque command Tcmd1 is obtained, if the motor is accelerating, and the obtained torque command Tcmd1 is found to not exceed a predetermined limit value K.sub.0, the torque command Tcmd1 is directly outputted as a torque command (a current command) Tcmd.sub.2 to each phase current loop circuit which controls the current flowing through each phase winding of the motor. If the torque command Tcmd1 exceeds the limit value K.sub.0, an amplitude I.sub.0 of the actual current is obtained. A limit value L is obtained based on a magnitude R(T) of the torque command Tcmd2 obtained one period before and the limit value K.sub.0. The torque command Tcmd1 is clamped by the limit value L to provide the torque command Tcmd2 to be supplied to the current loop. When the motor is decelerating, the control method compares the torque command Tcmd1 with the predetermined limit value K.sub.0 and the torque command Tcmd1 is not directly outputted as the torque command Tcmd2. When the motor is accelerating, the limit value L is obtained based on a ratio of the current command to the amplitude of the actual current, thereby generating the torque command Tcmd1 clamped at this limit value. Thus the output torque can be increased without decreasing the amplitude of the actual current. During deceleration, if the actual current increases due to a reverse electromotive force, the limit L decreases to reduce the command and, therefore, the actual current will not exceed the limit value.
摘要:
A feedforward control method for a servomotor designed to improve with the command follow-up property of a servo system. In this method, the average value of move commands for N number of position/speed loop processing periods centering around the position/speed loop processing period concerned is obtained, the number N being equal to the number obtained by dividing the distribution period by the position/speed loop processing periods. A position feedforward amount FFp is obtained by multiplying this average value by a position feedforward coefficient, and a corrected speed command Vc(j) is obtained by adding this position feedforward amount FFp to a speed command obtained in a conventional position loop processing. Further, a speed feedforward processing is executed (S16), a torque command Tc(j) is obtained, and the motor is thereby driven. This feedforward control never causes any variation in the position deviation or any shock on the motor or machine.
摘要:
A method for controlling a servomotor, in which the differences in dynamic characteristics among machines are absorbed by the controller so as to substantially equalize the response characteristics of the machines. An advance smoothing processing is executed before each position-speed loop processing cycle. The position feedforward amount FFp is calculated according to the following equation:FFp=.alpha.{(1-K) SMD.sub.0 +kSMD.sub.1 }.Where, SMD.sub.0 represents a smoothing data of the present cycle; SMD.sub.1, a smoothing data of the preceding cycle; and .alpha., a position feedback coefficient. The parameter k given in the above equation is adjusted to adjust the response characteristics of the individual machines, as well as the response characteristic of the mechanical system including controller with respect to an operation command. With this adjustment, the dynamic characteristics can be equalized between two or more machines even when such machines are simultaneously interpolated.
摘要:
A method for applying backlash acceleration correction at an optimum time preceding a reversal of velocity commands by a fixed time period, without being influenced by feed velocity or the like. A move command for a distribution period immediately preceding a present period is subtracted from a move command for a subsequent period to obtain an acceleration of the present period, the absolute value of the acceleration is multiplied by a constant K which is dependent on the frictional force of a machine, and the value obtained is stored in a register A. When a reversal of move commands occurs, backlash acceleration correction is initiated at a point of time when a velocity command corrected by a feedforward quantity FF has become equal to the value stored in the register A. Consequently, the backlash acceleration correction is initiated at a predetermined time before the reversal of sign of the velocity command.
摘要:
A servo-control apparatus generates a velocity command by applying backlash correction data to position error data when direction of rotation of a servomotor is reversed, and performs a backlash correction by adding an amount of backlash acceleration to the velocity command. In order to terminate backlash acceleration at an appropriate time, velocity feedback pulses are accumulated by a counter from the moment acceleration control starts, and the accumulated value of velocity feedback is monitored by an acceleration-stop instructing unit. When the accumulated value attains a predetermined value, an acceleration output unit is caused to halt the output of the amount of backlash acceleration to complete control of backlash acceleration.
摘要:
The invention provides a servomotor control apparatus which performs standard mode-type velocity control. An acceleration signal is formed by a differential computation or difference computation, from a velocity signal fed back from a servomotor. An acceleration value of the servomotor (d) is estimated by a criterion model (2) of a velocity control system utilizing a current command T(S) formed in a velocity control loop. The computed acceleration and the estimated acceleration are compared and the current command T(S) is corrected in conformity with the results of the comparison.
摘要:
A motor drive apparatus includes a rectifier which converts AC power to DC power and DC power to AC power, an inverter which converts the DC power output by the rectifier to AC power and supplies the AC power to a motor, and which converts regenerative power from the motor to DC power and returns the DC power to the rectifier, a DC voltage detection unit which detects a DC output voltage of the rectifier, an AC voltage detection unit which detects an AC output voltage of the rectifier, a frequency calculation unit which calculates the frequency of the AC voltage; a storage unit which stores as a reference value the DC voltage at the start of the regenerative operation, and a power failure detection unit which determines the presence or absence of a power failure by using the DC voltage, the reference value, and the AC voltage frequency.
摘要:
A motor driving apparatus is provided that performs AC/DC conversion by suppressing harmonics of the input at the time of normal operation, while on the other hand, allowing system operation to continue in the event of an overload by avoiding system stoppage. The motor driving apparatus, which drives a motor by supplying power from an AC power supply, includes: an AC/DC converter having a converter operation mode which is switched between a PWM converter operation mode in which an AC input voltage is converted into a DC voltage by applying PWM control to a plurality of power switching devices connected in serial and parallel fashion and a diode rectifier operation mode in which an AC input voltage is converted into a DC voltage by using a plurality of diodes each connected in reverse parallel with an associated one of the plurality of power switching devices; and a converter control unit which dynamically switches the converter operation mode of the AC/DC converter according to a load during powering of the motor.