摘要:
A motor drive apparatus 1 having a dynamic braking circuit 5 for producing a deceleration torque utilizing a braking force caused by a synchronous motor 4 acting as a generator when the synchronous motor 4 is deenergized, is equipped with a dynamic braking circuit fault detection capability, and comprises: a DC power supply 2 which is obtained by rectifying input AC power; voltage application means 2, 3, 10, 11 for applying a voltage to the windings of the synchronous motor 4 and to the dynamic braking circuit 5 for a predetermined length of time by switching power transistors A to F connected to the DC power supply 2; current detection means 6 for detecting the value of a current flowing from the power transistors A to F; and fault checking means 11 for checking the dynamic braking circuit 5 for the presence or absence of a fault, based on the current value detected by the current detection means 6 and on a predefined threshold value. With this configuration, detection of faults in the dynamic braking circuit is accomplished without requiring the addition of a contact signal or a control circuit.
摘要:
A control apparatus for controlling a die cushion mechanism including a servo-motor as a drive source and producing a force adapted to be applied to a slide in a press machine. The control apparatus includes a force commanding section for commanding a force to be produced by the die cushion mechanism; a force detecting section for detecting the force produced by the die cushion mechanism; a motor-speed detecting section for detecting an operating speed of the servo-motor; a slide-speed detecting section for detecting a moving speed of the slide; and a force controlling section for executing a force control on the servo-motor, based on a force command value commanded by the force commanding section, a force detected value detected by the force detecting section, a motor-speed detected value detected by the motor-speed detecting section and a slide-speed detected value detected by the slide-speed detecting section.
摘要:
A control device (10) for a die cushion mechanism that produces a force for a slide (24) in a press machine, comprising slide velocity command-forming means (61) for forming a velocity command for the slide (24), die cushion velocity command-forming means (62) for forming a velocity command for said die cushion (20), and velocity relation calculation means (65) for calculating a velocity relation between the velocity of the slide and the velocity of the die cushion based on a rate of increase (dF) in the force produced between the slide and the die cushion immediately after the collision of the slide with the die cushion. The cushion velocity command-forming means forms the velocity command for the die cushion based upon the slide velocity command formed by the slide velocity command-forming means and upon the velocity relation calculated by the velocity relation-calculation means. This makes it possible to form an optimum velocity command for the slide and/or the die cushion.
摘要:
A motor control system capable of securing stability and rapidity of motion even in a machine where the stability varies in accordance with a position of a driven member. The driven member and a motor for driving the driven member are operatively connected through a transmission mechanism including a nonlinear element such that a rate of change of the position of the driven member with respect to the position of the motor varies in dependence on the position of the motor. Optimum values of multiplier factors of operation constants with respect to the position of the driven member or the rotational position of the motor for the position control and the velocity control are stored in a data table. The values of the multiplier factors of the operation constants for a present position of the driven member or a present position of the motor are determined using the data table and the determined values of the multiplier factors are multiplied by reference operation constants to update the operation constants. The position and/or velocity control processing is performed using the updated optimum operation constants in accordance with the present position of the driven member or the present rotational position of the motor.
摘要:
In the control of a synchronous motor having a permanent magnet, an alternating current power supply voltage that is input to a power amplifier or a direct current link voltage of which input voltage is rectified is measured. A reactive current (a d-axis current) or a current control phase advance is changed, according to this power supply voltage. With this arrangement, reactive current control or current phase control can be carried out directly according to a change in the input power supply voltage. A motor control device includes a voltage measuring unit that measures a voltage supplied to a driving amplifier, and a current control unit that controls a current passed to a synchronous motor based on the measured voltage. The voltage measuring unit measures a voltage supplied to the amplifier. The current control unit controls a current that is passed to the synchronous motor, according to the measured voltage. As a result, the motor control device can directly control the current according to a change in the input power supply voltage to the motor.
摘要:
A device for controlling a die cushion mechanism including a servo-motor as a drive source and producing a force adapted to be applied to a slide in a press machine. The device includes a section for commanding a force to be produced by the die cushion mechanism; a section for detecting a force produced by the die cushion mechanism and applied to the slide; a section for detecting a moving speed of the slide; and a section for executing a force control on the servo-motor. The force controlling section executes force controls in mutually different modes on the servo-motor, through mutually different control loops, one mode being provided for an initial stage defined from an instant when the die cushion mechanism starts producing the force to be applied to the slide until a predetermined subsequent instant, and another mode being provided for a succeeding stage defined after the predetermined subsequent instant, by using at least a slide-speed detected value detected by the slide-speed detecting section. The force controlling section includes a section for preparing a first speed-command value to be commanded to the servo-motor in the initial stage and a second speed-command value, different from the first speed-command value, to be commanded to the servo-motor in the succeeding stage
摘要:
A control device for a press machine, by which one of the slide and the die cushion is suitably controlled, when a malfunction occurs in the other, such that the force between the slide and the die cushion does not excessively increase. The control device includes a slide control part for controlling the motion of the slide and a die cushion control part for controlling the motion of the die cushion. A first transmitter transmits an abnormal signal from the die cushion control part to the slide control part when a first detector detects a malfunction of the die cushion. The slide control part is configured to move the slide, when receiving the abnormal signal, such that the slide is away from the position of the die cushion at the time of receiving the abnormal signal by a certain distance and, to stop the slide.
摘要:
First and second acceleration detection means are attached to first and second sections on a driven body, and values of accelerations α1 and α2 in travel direction of the driven body are detected. On the basis of the difference or sum of the acceleration values α1 and α2, at least one of a position command, speed command, or current command for performing drive control of the driven body is corrected.
摘要:
A servo motor for driving a die is provided with position and speed detectors. Further, a pressure sensor for detecting the pressure applied to a workpiece is provided. In the servo motor control unit, the smaller one of the speed command obtained by feedback control of the position and the speed command obtained by the pressure feedback control is selected as an output of a comparator. Based on the speed command output from the comparator, feedback control of the speed is performed and the servo motor is driven. In the state where the die does not press against the workpiece, a pressure error is large, the speed command by pressure control becomes large, and the speed command by position control becomes small. Therefore, position control is performed. When the workpiece is pressed, the position error increases, and the pressure error decreases, a speed command by pressure control is employed and pressure control is performed.
摘要:
A servomotor control device for a robot which can adjust the characteristics of maximum torque and/or continuous rated output of the servomotor and a robot with easy maintenance. The robot is commanded to execute one cycle of taught motion. During the cycle, a maximum torque required for the servomotor is calculated by a torque command or the like. When the maximum torque lacks, a field weakening current correction value is increased for increasing d-phase current and the maximum torque. Further, lack of continuous rated output may be judged by detected temperature of the servomotor. When a lack of continuous rated output occurs, the correction value is decreased to decrease the d-phase current so as to adjust the characteristic of continuous rated output. Although the servomotors have the same specification, the characteristic of each of the servomotors may be optimized corresponding to the axis by adjusting the field weakening current (or the d-phase current). As the hardware such as the control devices have the same specification, manufacture, maintenance and control of the robot may become easier.