JPS61193710A - Method for monitoring roll driving - Google Patents

Abstract

PURPOSE:To detect axial torsion resonance, etc. and to suppress the same by approximating a roll driving system with a three-particles system consisting of a driving motor, reduction (over-drive) gear, roll and spindles connecting these and estimating the axial torsion angle, etc. CONSTITUTION:The roll driving system is expressed by the three-particles system consisting of the driving motor, the reduction or over-driver gear 12, the roll 14 and the spindles 16, 18 connecting the same. The armature current Ia and the speed omega1 of the motor 1 measured actually by an observing device 20 are inputted to said device from which disturbance load torque TL, the torsion angle theta1 of the spindle 16, the torsion angle theta2 of the spindle 18, the speed omega2 of the gear 12 and the speed omega3 of the roll 14 are outputted. The state of the roll driving system is thereby monitored and is further controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for monitoring the conditions of a roll drive system, typically a rolling mill, such as roll speed, spindle torsion angle, and disturbance load torque.

[Conventional technology]

In recent years, the steel industry has been increasingly formulating and implementing various measures to improve quality and yield. In the steel plate manufacturing process, a rolling mill is used to create the required thickness of the steel plate, but the speed setting accuracy and responsiveness of the rolling mill's roll drive system directly affect the quality and yield of the steel plate, so various improvements are being made. It is being Due to recent technological advances represented by digital technology, the speed setting accuracy of the roll drive system has become quite satisfactory, but the responsiveness is still insufficient for the reasons described below.

The roll drive system, typified by rolling mills, consists of a drive motor, a
It consists of a speed machine, a roll, and a spindle that connects them, all of which have mass and spring properties, so they constitute a vibration system. The axial torsional resonance point of this vibration system, which is determined by the moment of inertia and the axial torsional stiffness coefficient, is in the speed control frequency region in a roll drive system using a high-performance speed control device, so the gain of the speed control system can be sufficiently increased. (If it is raised, the gain at the resonance point in the Bode diagram will become more than 1, which may lead to automatic vibration and breakage of the gear), and furthermore, it will not be possible to sufficiently increase the response. Can not.

If the responsiveness is insufficient, for example, when a steel plate is caught in a roll, the impact drop will be large and a large amount of off-gauge will occur. Therefore, to improve yield, it is essential to improve the responsiveness of the roll drive system, and to do this, the gain of the automatic speed control system is increased, and the axial torsional vibration that is likely to occur due to this is detected by strain gauges and fed back. It is possible to suppress it. However, strain gauges require a power source and are difficult to install on a rotating body such as a spindle. In addition, if a battery is used as a power source, it consumes a lot of energy, making constant monitoring difficult.

[Problem that the invention seeks to solve]

Therefore, the present inventor approximated the roll drive system with a two-mass system of the drive motor and the roll, and estimated the spindle torsion angle, roll speed, and disturbance load torque using calculation formulas from the drive motor speed and armature current, which are easy to measure. A monitoring device was developed and proposed earlier (Japanese Patent Application No. 59-34037). As a result of manufacturing this monitoring device and testing it on an actual machine, it was found that although the general trends of the three signals mentioned above can be obtained with this monitoring device, detailed changes cannot be obtained, and improvements in response are still unsatisfactory. It was.

Roll drive systems decreased (increased) in addition to drive motors and rolls.
If quick production is added, it becomes a 3-mass point system, and if further subdivided, it becomes a 4-mass point system or a 5-mass point system. In a two-mass system, there is one resonance point, and this only shows the approximate tendency of the roll drive system, which is a multi-mass system. If it is treated as a multi-mass point system, there will be many resonance points and fine changes can be obtained, but the configuration of the monitoring device will be complicated.

Therefore, by approximating the roll drive system with a three-material point system and configuring a monitoring device, it was found that not only general trends but also minute changes could be obtained for the three signals mentioned above, which could be fully utilized for improving responsiveness.

[Means for solving problems]

In the roll drive monitoring method of the present invention, the roll drive system is approximated by a three-material system consisting of a drive motor, a speed reducer, a roll, and a spindle that connects these, and the speed and armature current of the drive motor are actually measured. The present invention is characterized in that an observation device is used to estimate the reduced (increased) aircraft speed, roll speed, spindle torsion angle, and disturbance load torque, and the state of the roll drive system is monitored based on the output of the observation device. .

In the present invention, the roll drive system is represented by a three-mass system consisting of a drive motor 10, a speed reducer or speed increaser 12, a roll 14, and a spindle 16, 18 that connects these, as shown in FIG. 1. ω1.ω2. ω3 is the speed of the motor 10. Decreasing (increasing) speed 12, the speed of the roll 14, Jl, J2, J3 are the moments of inertia, θl, θ2 are the torsion angles of the spindle 16, 18. Armature current of the drive DC motor 10 Ia is the armature resistance, Ra is the armature reactance, La is the armature reactance, KT is the torque coefficient, Ke is the voltage coefficient, Va is the applied voltage, and the torsional rigidity coefficient of the spindle 16.18 is +.

When k2 is set, the following formula holds true.

θ1=ω! -ω2 l θ2; ω2-ω3J2n2-
to 1θ1- to 2θ2゜J 3 pretend = to 2θ 2TLKT Ia=J
+a11++θI Va=La I a+Ra I a+Keω1 These can be expressed as a determinant as follows.

(1) In these equations (1) and (2), the following equation (3) is assumed.

TL=0...
(3) Since Va, Ia, and ω1 can be easily measured in these equations, the remaining θ1. θ2. ω2ω
3. Considering estimating TL, this is the following (4)
If the formula holds, estimation is possible, and the formula (4) holds.

......(6) θ1. θ2. ω2. ω3. The calculation formula for estimating TL can be obtained using a known method, and the results can be expressed as (7) to (14)
) is shown in the formula.

k=large−Z+, #y,”
-(71X=1.C+Dy
・・・・・・(8) Z=(Z+ Z2 Z3 Z
4 Z5) ...(91... (12) ...... (13) ...... (14) The block diagram of the above estimation circuit (observer 20) is shown in the second block diagram. As shown in the figure.

For example, from formula (8) QO) α1) 04, TL=ZI+a
Q++, θ1-Z2+bωl, θ2=Z3+C
ωh..., but it is also like that in Figure 2, and Zl is +7) (9) U (From equation 1, Z
l =a12 Z 2 +b11 Q) + +b12
This is also the case in Fig. 2 for Ta.

The following shall apply accordingly.

〔Effect of the invention〕

TL is performed by inputting the actually measured armature current 1a and motor speed ω1 to the observation device 20 having the configuration shown in FIG.

θ1. θ2. ω2. By outputting ω3, the state of the roll drive system is monitored and further controlled. For example, in order to prevent spindle torsional resonance, θI and θ2 are monitored, and if these exceed predetermined values or their differential values show periodic changes, a signal is sent to the speed control system to increase the motor torque. reduce As a result, spindle torsional resonance can be prevented, so the gain of the control system can be increased at all times, and responsiveness can be improved.

In the present invention, since the roll drive system is approximated by a three-mass point system to estimate the shaft torsion angle, even minute changes can be estimated, and shaft torsion resonance etc. can be reliably detected and suppressed.

[Brief explanation of drawings]

FIG. 1 is a diagram explaining the present invention in detail, and FIG. 2 is a block diagram showing the configuration of an observation device. In the drawing, 10 is a drive motor, 12 is an amplifier, 14 is a roll, and 16.18 is a spindle.

Claims (1)

[Claims] The roll drive system is approximated by a three-mass system consisting of a drive motor, a speed reducer, a roll, and a spindle that connects these, and the reduction (
(b) A roll drive monitoring method characterized by using an observation device for estimating machine speed, roll speed, spindle torsion angle, and disturbance load torque, and monitoring the state of the roll drive system based on the output of the observation device.