摘要:
A method for changing a force control gain expressed as a ratio of force error to velocity command value in a control circuit performing a force control of a servo motor driving a die cushion disposed opposite to a slide in a press machine. The method includes: obtaining a difference between a displacement of the slide and a displacement of the die cushion in a state in which the slide and the die cushion collide with and are exerting force on each other; detecting the force when the difference of the displacements is obtained; calculating a spring constant of a structural portion based on a proportionality between the difference of the displacements and the force, when regarding the structural portion including the slide and the die cushion as an elastic structure; and changing the force control gain based on the spring constant using a fixed proportionality that exists between the force control gain and a reciprocal of the spring constant.
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:
An imaging system includes an infrared lamp to emit infrared light, a CCD camera (5) to pick up an image of a place irradiated with the infrared lamp and convert the picked-up image into an electric signal, and an image processing unit (7) to periodically change a signal accumulation time of the CCD camera and periodically and continuously provide images of different exposure values. The image processing unit extracts a high-brightness block surrounded with a medium-brightness area from a first image of the periodically provided images, and according to a degree of the medium-brightness area, controls a signal accumulation time of a second image to be picked up.
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:
A speed region of a motor is divided into a region lower than a first switch speed VS1, a region higher than a second switch speed VS2 and a region between the first and second switch speeds. An abnormal load determination level to be compared with an estimated load obtained by an observer is set for each of the regions. An abnormal load determination level AL4 applied when an acceleration exceeds a threshold value is set. The abnormal load determination level AL4 is used for comparison with the estimated load until a predetermined period of time elapses after the acceleration to be commanded to the motor, which once exceeded the threshold level, drops. In other cases, the estimated load is compared with the abnormal load determination level having a value according to the speed. If the estimated load exceeds the compared abnormal load determination level, it is judged that a collision is detected.
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.