ROTATIONAL SPEED CONTROL SYSTEM FOR ROLLING MILL POURING REELS

Abstract

A rolling mill pouring reel automated control system for dynamically regulating pouring reel rotational speed based at least in part on forward velocity of rolled stock product approaching the pouring reel. Product forward velocity is sensed by the control system that in turn uses the sensed forward velocity to adjust the pouring reel steady state rotational speed and/or wobble oscillation of the rotational speed. The control system preferably regulates the interrelationship between the product forward velocity and reel rotational speed in a closed feedback loop.

Description

BACKGROUND

1. Field

Embodiments of the present invention relate to pouring reels used in rolling mills, and more particularly to automated control systems for dynamically regulating pouring reel rotational speed based at least in part on forward velocity of rolled stock product approaching the pouring reel that is sensed by the system.

2. Description of the Prior Art

In steel mill practice, it is common to coil rolled stock product S (e.g., round rod having a diameter of approximately 25 mm (1 inch) or greater) in a helical configuration in a so-called “pouring reel”. A typical pouring reel has a vertically oriented, open-top drum portion and a central vertically oriented mandrel that defines a generally annular space there between. The mandrel and/or drum may comprise solid outer surfaces or a plurality of spaced bars or the like. An exemplary pouring reel structure is shown and described in U.S. Pat. No. 3,020,000, the entire contents of which is incorporated by reference herein.

The known pouring reel is rotated at a designated speed ω for receipt and coiling of product advancing along the rolling line at a forward velocity or speed V_S. In order to compact product efficiently in the reel, it is often desired to coil the product helix radially in a row between the mandrel and drum, then form a new row on top of the previous row by winding in the opposite radial direction. The back and forth radial winding is performed until the drum is filled to a desired level. An upstream shear mechanism shears the product prior to complete drum filling, whereupon the sheared distal end is eventually reeled into the drum.

Radial coiling of product stock within a row is accomplished by varying the reel rotational speed in a repetitive oscillating “wobble” pattern of speed and frequency that is superimposed on the reel's steady state rotational speed. The wobble rotational speed variation in turn proportionally varies outwardly directed radial centrifugal force on the product stock S (F_{cen S}) that is captured within the annular space between the drum and mandrel.

Relationship and coordination between the product forward velocity V_S and pouring reel rotational speed ω (the combination of steady state and wobble) is important for optimizing coiled product windings and quality. If the product forward velocity is too great relative to the reel rotational speed excessive length of product will be introduced within the reel annular space before it can be wound efficiently, possibly gouging or scarring product against the drum during impact or subsequent winding. Outer coils in the coil bundle may also be gouged by sliding contact with the drum inner diameter as the completed coil is separated from the reel. In a worst case scenario excess product stock may jam within the pouring reel, effectively shutting down the rolling mill line until the jammed material is removed and any damaged equipment is repaired.

Conversely, if the reel rotational speed is too fast relative to the product forward velocity into the reel, the product may be wound too tightly, causing potential product gouging or scarring by contact with the mandrel during the pouring operation or when the coiled product is separated from the mandrel during coil unloading. Excessive tension during winding may cause stock product stretching to a diameter below specification. Reel rotational and wobble speeds are generally pre-set for a given product forward velocity, with a human operator having limited adjustment of either in response to variations in coiling operation quality.

Coiling operation quality is monitored after formation of a coil, but not controlled in real time during coil formation by a human operator. A human operator cannot observe directly how the product is coiling within the reel. After formation of a coil bundle and removal from the pouring reel the operator can observe after the fact how the coils were wrapped within the reel and has limited human control to adjust the reel's wobble oscillation for a future coil formation (i.e., not during a specific coil formation in real time). The human control is also reactive in nature because it does not include information about upcoming variations in product forward velocity along the rolling mill line.

SUMMARY

Accordingly, embodiments of the present invention include a rolling mill pouring reel automated control system for dynamically regulating pouring reel rotational speed based at least in part on forward velocity of rolled stock product approaching the pouring reel. Product forward velocity is sensed by the control system that in turn uses the sensed speed to adjust the pouring reel steady state rotational speed and/or wobble oscillation of the rotational speed. The control system preferably regulates the interrelationship between the product forward velocity and reel rotational speed in a closed feedback loop.

Another exemplary embodiment includes a method for coiling rolled product in a rolling mill pouring reel, by sensing actual forward velocity of rolled product prior to entry into a pouring reel with a sensor system; and dynamically varying pouring reel actual rotational speed based at least in part on the sensed forward velocity of the rolled product.

These and other embodiments can be achieved in accordance with the present invention by a control system for a rolling mill pouring reel that includes a pouring reel controller adapted for operative coupling to a rolling mill pouring reel drive system, for dynamically varying pouring reel actual rotational speed by outputting a reference rotational speed to the drive system that causes the drive system to conform the actual rotational speed to the reference rotational speed. The control system also has a sensor system, coupled to the pouring reel controller, adapted for sensing forward velocity of rolled product prior to entry into a pouring reel, for inputting forward velocity information to the controller. When operatively coupled to a rolling mill pouring reel, the pouring reel controller dynamically varies the reference rotational speed based at least in part on the sensed forward velocity. In some embodiments the pouring reel controller further comprises a closed loop control system that utilizes the forward velocity as an input thereof and generates the reference rotational speed as an output thereof. In some embodiments the closed loop control system utilizes a control function selected from the group consisting of proportional-integral-differential control and adaptive control. In some embodiments the sensor system is selected from the group consisting of ultrasonic sensors, Doppler sensors, optical sensors, and laser optical sensors. In other embodiments, rotational speed of one or more motors driving the last stand and/or pinch rolls before the pouring reel is correlated to the product forward velocity as the product passes through those respective rolls.

The features of the present invention may be applied jointly or severally in any combination or sub-combination.

Further features of embodiments of the present invention, and the advantages offered thereby, are explained in greater detail hereinafter with reference to specific embodiments illustrated in the accompanying drawings, wherein like elements are indicated by like reference designators.

BRIEF DESCRIPTION OF THE DRAWINGS

The teachings of the present invention can be readily understood by considering the following detailed description in conjunction with the accompanying drawings, in which:

FIG. 1 shows a schematic view of a rolling mill with pouring reels that are controlled by a pouring reel control system, in accordance with an exemplary embodiment of the present invention;

FIG. 2 shows a schematic view of the pouring reel control system, including a rolled stock product forward velocity sensor system, in accordance with an exemplary embodiment of the present invention;

FIG. 3 shows a schematic view of the pouring reel control system, including an alternative embodiment of rolled stock product forward velocity sensor system, in accordance with another exemplary embodiment of the present invention;

FIG. 4 shows a schematic of a computer or controller that is utilized in a pouring reel control system, in accordance with an exemplary embodiment of the present invention;

FIG. 5 shows a graphical representation of changes in coiling reel rotational speed and wobble oscillation frequency ω_R before and after a change in rolled stock forward velocity V_S, in accordance with an exemplary embodiment of the present invention; and

FIG. 6 shows a graphical representation of changes in the reference or target coiling reel rotational speed and wobble oscillation frequency ω_REF sent from the pouring reel control system controller to the coiling reel rotational drive system, in accordance with an exemplary embodiment of the present invention.

To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures.

DETAILED DESCRIPTION

After considering the following description, those skilled in the art will clearly realize that the teachings of the present invention can be readily utilized in a rolling mill pouring reel automated control system for dynamically regulating pouring reel rotational speed based at least in part on forward velocity of rolled stock product approaching the pouring reel. Product forward velocity is sensed by the control system that in turn uses the sensed forward velocity speed to adjust the pouring reel steady state rotational speed and/or wobble oscillation of the rotational speed. The control system preferably regulates the interrelationship between the product forward velocity and reel rotational speed in a closed feedback loop, which optionally can be performed automatically and/or in real time.

Rolling Mill Pouring Reel Operative Environment

FIG. 1 depicts an exemplary rolling mill 10 for rolled elongated product stock S. The rolling mill 10 includes a rolling station 20 that in turn includes a plurality of orthogonally oriented driven rolls, which in this figure are driven horizontal rolls 22 and vertical rolls 24. The rolls 22, 24 do not have to be oriented vertically and horizontally, so long as they maintain 90° relative orientation. Product S is advanced out of the rolling station 20 by a pair of rollers in last roll stand 50. The last stand 50 rollers are driven by one or more motors 52 that are powered by drive/controller 54. The last stand 50 may also incorporate rolls parting (i.e., the gap between the rolls through which product S passes) sensing and adjustment mechanisms, as depicted by the bi-directional arrows (in FIG. 2) for each roll. The advancing product S, having an forward velocity V_S, passes from the last stand 50 to shearing station 30, for shearing the product S to a desired length. In many known rolling mills a switch downstream of the shearing station 30 directs product to one or the other of a pair of parallel pouring reel stations 40, so that each reel station alternatively receives product as a completed coil is unloaded from the other station. For simplicity, FIG. 1 does not show the known switch or the second pouring reel station. After the switch (not shown) routs product S to the pouring station shown in FIG. 1 trough arrangement 42 receives product, where it is subsequently advanced to a pair of pinch rolls 60. The pinch rolls 60 are powered by motor 62 and drive/controller 64.

Product S exiting the pinch rolls 60 passes through guide 66 and is deposited in pouring reel 70. The pouring reel 70 has a drum 72 and mandrel 74, and is rotatively driven at rotational speed ω_R by one or more motors 76 and drive controller 78. As is known, coordination of the product S actual advancing speed V_S and actual rotational speed ω_R results in coiling of product within the pouring reel 70. The rolling mill 10 components 20-78 are of known operation and construction. In previously known operational modes of the rolling mill 10, a human operator monitors the product S coiling within the pouring reel 70 and performs a limited range of steady state rotational speed or oscillation/wobble adjustment (after inspection of a completed coil), in an effort to maintain satisfactory coiling in subsequently formed coils, in reaction to upstream induced variations in the actual advancing speed V_S. However, as previously noted, in known systems such adjustment is not in real time and does not impact formation of a coil presently being formed in the pouring reel 70.

Pouring Reel Control System

The pouring mill control system is shown in FIGS. 2-4. Sensor system 80 senses the actual product S forward velocity V_S as the product approaches the guide 66 and pouring reel 70. As shown in n FIG. 2 the sensor system 80 can be oriented between the last stand 50 and pinch rolls 60. Many speed sensors suitable for application in a rolling mill operative environment may be utilized, including by way of non-limiting example ultrasonic sensors, Doppler sensors, and optical sensors including laser optical sensors. Alternatively, as shown in FIG. 3, the speed sensor function can be accomplished by correlating the pinch rolls 60 motor 62 rotational speed ω₆₀ that is measured by encoder 80′ with the product S forward velocity. In the embodiment of FIG. 3 the encoder 80 rotational speed ω₆₀ information is used by the pouring reel control system to determine indirectly product S forward velocity V_S. Pinch rolls motor rotational speed ω₆₀ is then correlated with product forward velocity V_S by the pouring reel control system.

The pouring reel control system also has a pouring reel controller 90, which is shown as a programmable logic controller (PLC). Other types of controllers may be substituted for the PLC, including personal computers and dedicated hardware controllers. PLC 90 receives product S forward velocity V_S information from the sensor system 80 via communications pathway 86 and based on that forward velocity dynamically determines a coiling reel reference rotational speed ω_{R REF} for achieving desired product S coiling specifications, using known calculation or empirical or statistical methodologies. The reference rotational speed is often a composite of a steady state speed and an overlaid oscillating or wobble speed profile for achieving radially directed coiling of the product S within the pouring reel 70. The PLC 90 can dynamically vary the coiling reel reference rotational speed ω_{R REF} automatically and/or in real time.

As is shown in FIGS. 2 and 3, the pouring reel controller 90 can utilize a closed control loop with the actual product speed V_S as an input and the desired reel reference rotational speed ω_{R REF} as an output. Many known industrial process control functions or methodologies may be utilized by the reel controller PLC 90 for determining the desired reel reference rotational speed ω_{R REF}, including by way of non-limiting example proportional-integral-differential control, adaptive control, and artificial neural network control. The calculated reference rotational speed ω_{R REF} may be outputted via communications pathway 88 to the coiling reel drive control 78/motor 76, which in turn can conform the coiling reel actual rotation speed ω_R to the desired reference speed. The product forward velocity speed sensing V_S, determination of desired reel reference rotational speed ω_{R REF} and responsive varying of the actual rotational speed ω_R are performed dynamically and continuously (optionally automatically and/or in real time) by the automated pouring reel control system.

If desired, changes in sensed product forward velocity or speed V_S, pouring reel actual rotational speed ω_R or other operational information may be communicated by the reel controller 90 via a communications pathway, such as bi-lateral communications data bus 92 to other devices, such as human machine interface (HMI) 94 or other rolling mill controllers. Using the example of the speed sensor system 80 embodiment of FIG. 3, if a separate rolling mill pinch roll controller supervises operation of pinch roll 60 drive 64 and has information about that drive's rotational speed ω₆₀, that rotational speed information may be communicated to the pouring reel controller 90 via data bus 92. Reel controller 90 can in turn correlate the pinch rolls, or their drive 60 rotational speed information ω₆₀ with the product S forward velocity V_S that is passing through the pinch rolls.

Referring to FIG. 4, the pouring reel controller PLC 90 has a controller platform 100 that includes a processor 110 and a controller bus 120 in communication therewith. Processor 110 is coupled to one or more internal or external memory devices 130 that include therein operating system 140 and application program 150 non-transient software module instruction sets that are accessed and executed by the processor, and cause the pouring reel controller 90 to perform the previously described dynamic varying of pouring reel actual rotational speed ω_R control operations based on product advancement actual speed V_S. Non-transient software module instruction sets used to perform the pouring reel control functions described herein may be stored on a software storage medium apparatus and subsequently loaded into the controller platform memory devices.

While reference to an exemplary controller platform 100 architecture and implementation by software modules executed by the processor 110, aspects of the present invention may be implemented in various forms of hardware, software, firmware, special purpose processors, or a combination thereof. Preferably, aspects of the present invention are implemented in software as a program tangibly embodied on a program storage device. The program may be uploaded to, and executed by, a machine comprising any suitable architecture. Preferably, the machine is implemented on a computer platform having hardware such as one or more central processing units (CPU), a random access memory (RAM), and input/output (I/O) interface(s). The computer platform 100 also includes an operating system and microinstruction code. The various processes and functions described herein may be either part of the microinstruction code or part of the program (or combination thereof) which is executed via the operating system. In addition, various other peripheral devices may be connected to the computer/controller platform 100.

It is to be understood that, because some of the constituent system components and method steps depicted in the accompanying figures are preferably implemented in software, the actual connections between the system components (or the process steps) may differ depending upon the manner in which the present invention is programmed. Specifically, any of the computer platforms or devices may be interconnected using any existing or later-discovered networking technology and may also all be connected through a lager network system, such as a corporate network, metropolitan network or a global network, such as the Internet.

Computer/controller platform 100 receives input communications from one or more input devices I via respective communications pathways I′ through input interface 160, that in turn can distribute the input information via the controller bus 120. The controller platform 100 also has a communications interface 170 for communication with other controllers on a shared external data bus, such as the data bus 92. Output interface 180 facilitates communication with one or more output devices O via associated communications pathways O′. In the present invention the computer/controller platform 100 in the pouring reel control system controller 90 is associated with input devices I/associated input communications pathways I′ that include the speed sensor system 80 and its associated communication pathway 86. Output devices O/associated output communications pathways O′ that are associated with that computer/controller platform 100 include the desired reel reference rotational speed ω_{R REF} that is communicated to the pouring reel 70 motor 76/drive controller 78 by communication pathway 88.

Operational response of the pouring reel control system of the present invention is depicted in representative speed and frequency graphs of FIGS. 5 and 6. FIG. 5 shows actual product forward velocity V_S and pouring reel actual rotational speed/wobble oscillation frequency ω_R. FIG. 6 shows the desired reel reference rotational speed ω_{R REF} determined by the pouring reel controller 90, based on the product S forward velocity V_S information received from the speed sensor system 80. Comparing the two figures, a drop in the product S forward velocity V_S alters (e.g., lowers) the desired reel reference rotational speed ω_{R REF} that in turn alters the actual pouring reel rotational speed ω_R.

Although various embodiments, which incorporate the teachings of the present invention, have been shown and described in detail herein, those skilled in the art can readily devise many other varied embodiments that still incorporate these teachings.

Claims

1. A method for coiling a rolled product in a rolling mill pouring reel, comprising:

sensing forward velocity of the rolled product prior to entry into a pouring reel with a sensor system; and

dynamically varying pouring reel actual rotational speed based at least in part on the sensed forward velocity of the rolled product.

2. The method of claim 1, wherein the dynamically varying step is performed in a closed loop control system utilizing the forward velocity as an input and outputting a reference rotational speed that the pouring reel will utilize to adjust its actual rotational speed.

3. The method of claim 2, wherein the closed loop control system utilizes a control function selected from the group consisting of proportional-integral-differential control, adaptive control and artificial neural network control.

4. The method of claim 3, wherein the sensor system is selected from the group consisting of ultrasonic sensors, Doppler sensors, optical sensors, laser optical sensors, and correlation of rolling mill rolls rotational speed with the rolled product forward velocity that is passing through said rolls.

5. The method of claim 1, wherein the dynamically varying step is performed automatically based on the sensed forward velocity of the rolled product.

6. The method of claim 1, wherein the dynamically varying step is performed in real time based on the sensed forward velocity of the rolled product.

7. The method of claim 1, wherein the sensor system is a non-contact sensor system selected from the group consisting of ultrasonic sensors, Doppler sensors, optical sensors, laser optical sensors, and correlation of rolling mill rolls rotational speed with the rolled product forward velocity that is passing through said rolls.

8. The method of claim 1, wherein the dynamically varying step is performed automatically and in real time based on the sensed forward velocity of the rolled product.

9. A computer software storage medium apparatus, comprising:

non-transient software stored in a non-volatile storage medium for operating a rolling mill pouring reel actual rotational speed control system that is coupled to said pouring reel, the control system having a processor coupled to a memory device, the control system capable of retrieving and storing a copy of said software from said medium and causing said processor to execute said software to control the pouring reel actual rotational speed by:

determining forward velocity of the rolled product prior to entry into the pouring reel with a speed sensor coupled thereto; and

dynamically varying pouring reel actual rotational speed based at least in part on the forward velocity of the rolled product.

10. The apparatus of claim 9, wherein the software causes the processor to perform the dynamically varying step with a closed loop control system utilizing the forward velocity as an input therein and outputting a reference rotational speed that the pouring reel will utilize to adjust its actual rotational speed; the closed loop control function selected from the group consisting of proportional-integral-differential control, adaptive control, and artificial neural network control.

11. A control system for a rolling mill pouring reel, comprising:

a pouring reel controller adapted for operative coupling to a rolling mill pouring reel drive system, for dynamically varying pouring reel actual rotational speed by outputting a reference rotational speed to the drive system that causes said drive system to conform the actual rotational speed to the reference rotational speed; and

a sensor system, coupled to the pouring reel controller, adapted for sensing forward velocity of rolled product prior to entry into a pouring reel, for inputting forward velocity information to the controller;

wherein the pouring reel controller dynamically varies the reference rotational speed based at least in part on the sensed forward velocity.

12. The system of claim 11, wherein the pouring reel controller further comprises a closed loop control system that utilizes the forward velocity as an input thereof and generates the reference rotational speed as an output thereof.

13. The system of claim 12, wherein the closed loop control system utilizes a control function selected from the group consisting of proportional-integral-differential control, adaptive control, and artificial neural network control.

14. The system of claim 13, wherein the sensor system is selected from the group consisting of ultrasonic sensors, Doppler sensors, optical sensors, laser optical sensors, correlation of rolling mill rolls rotational speed with the rolled product forward velocity that is passing through said rolls.

15. The system of claim 11, wherein the dynamically varying step is performed automatically based on the sensed forward velocity of the rolled product.

16. The system of claim 11, wherein the dynamically varying step is performed in real time based on the sensed forward velocity of the rolled product.

17. The system of claim 11 operatively coupled to a rolling mill comprising:

a plurality of rolling stands for rolling elongated product stock to a rolled shape;

a pinch roll downstream the rolling stands for advancing the rolled product to a pouring reel, wherein the sensor system is oriented proximal said pinch roll for sensing product forward velocity;

a pouring reel downstream the pinch roll for receiving and coiling rolled product therein;

a pouring reel drive system coupled to the pouring reel, for rotating the pouring reel to an actual rotational speed based on reference rotational speed outputs received from the pouring reel controller.

18. The system of claim 17, wherein the pouring reel controller further comprises a closed loop control system that utilizes the forward velocity as an input thereof and generates the reference rotational speed as an output thereof.

19. The system of claim 17, wherein the pouring reel controller dynamically varies the reference rotational speed automatically based on the sensed forward velocity of the rolled product.

20. The system of claim 17, wherein the pouring reel controller dynamically varies at least one rolling stand roll parting gap based on the sensed forward velocity of the rolled product.