Force control method with position inclination

Abstract

The invention relates to the field of engineering control, and particularly discloses a force control method with position inclination. The single-side actual force and the actual resultant force of the servo hydraulic cylinder are calculated according to the obtained size of the servo hydraulic cylinder and oil pressure data obtained by the oil pressure sensor, when the actual resultant force changes, the controller synchronously adjusts the roll gaps on the two sides through the hydraulic cylinder displacement sensor, and when the roll gaps on the two sides are kept inclined and synchronously opened, the roll gaps on the two sides are synchronously opened. Compared with a traditional equipment force control mode, the force control method has the advantages that the actual resultant force feedback is reduced, when the roll gaps on the two sides are kept inclined and the roll gaps are closed synchronously, the actual resultant force feedback is increased, and the resultant force is constant on the premise that the inclination angle of the roll gaps of the pinch rolls is kept unchanged. Equipment is kept stable, materials are prevented from easily deviating in the pinch roll, and stable center line control of the materials is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of engineering control, and in particular relates to a force control method with position tilt. Background Art

[0002] JLDG 1450HSM is a hot-rolled coil production line consisting of one roughing mill, seven finishing mills, and two coilers. The pinch rollers used for coiling are frame-type, which differs significantly from the traditional swing-arm type. Specifically, the pinch rollers have their own arches and locking beams, which provide greater rigidity and are beneficial for coiling products with greater strength or thickness. Four balancing cylinders are used to support the upper pinch rollers, and the upper beam locking cylinders are used to eliminate mechanical clearance. The pinch roller lifting process is driven by the main oil cylinder, which moves synchronously with the balancing cylinders. There are corresponding slideways on the arches to cooperate with the slide action of the upper roller set. The structure of this equipment is relatively complex.

[0003] Due to the relatively complex structure, a series of problems have arisen, as follows: the archway, slide plate and locking beam that come with the pinch roller need to be installed strictly in accordance with the assembly requirements, but there are problems with the assembly gap and assembly method on site, which causes the pinch roller to overcome additional resistance when moving, and the equipment slide gap will become more abnormal after long-term use; the balance cylinder is controlled by a single hydraulic overflow valve to control the pressure, and a three-way valve is used to supply oil to 4 cylinders, and the pipeline is long, generally more than 40 meters in length, and the pressure response capability is limited; a transition guide plate is provided between the pinch roller and the pressure roller. Under normal circumstances, the transition guide plate follows the pinch roller and the pressure roller up and down, but there is a problem with the mechanical design of the pressure roller in the equipment. The pressure roller will bear a large torque, and the large torque will cause frequent power outages, so the pressure roller does not press down, which makes the pinch roller continue to drag the transition guide plate when it descends.

[0004] Due to the aforementioned series of issues, the force control effect of the pinch rolls was less than ideal. Specifically, the force of the oil cylinder on the OS side of the equipment fluctuated periodically, with a fluctuation range of approximately 7kN, and sometimes as high as 15 to 20kN. The force of the oil cylinder on the DS side fluctuated from 4 to 5kN. For thin-gauge strip steel, the force setting was only 15 to 20kN. Such fluctuation values ​​almost fully met the processing force setting value, making it completely impossible for operators to achieve processing control.

[0005] While users can address the issue of force fluctuations in the equipment's cylinders by checking and adjusting the hydraulic station's oil supply pressure via accumulators, this doesn't resolve the problem immediately. Therefore, the only option is to minimize the adverse effects of this issue through automated means. Existing hot-rolled coil production lines have numerous automated components, each of which requires automated control via a programmable logic controller (PLC). Therefore, adjustments to these PLCs can address the aforementioned issue. The PLC L1 can be modified by adding periodic filtering before transmitting sensor force to the controller. In actual operation, the gap force exerted by the cylinder on the strip surface through the pinch rolls is controlled 0.68 seconds after the pinch rolls engage, resulting in a generally controlled result. However, the actual cylinder force still fluctuates, causing variations in the roll gap and affecting the final coil shape at the end of the steel. This is especially true after the F5 throw, when the strip's tension, speed, and temperature begin to fluctuate, exacerbating variations in pinch roll force.

[0006] Based on the above complex background, when using various methods such as adjusting the oil supply pressure of the hydraulic station to deal with the problem of tail curling, no obvious results were achieved. It is necessary to determine an operating method that can maximize the force control effect of the pinch roller. Summary of the Invention

[0007] In order to overcome the deficiencies of the prior art, the present invention aims to provide a force control method with position tilt to solve the problem that the force control effect of the pinch rollers of steel processing equipment cannot reach an ideal state due to reasons such as equipment assembly and structure.

[0008] To achieve the above object, the present invention provides the following technical solutions: A force control method with position tilt, comprising: Obtaining dimensional data of the servo hydraulic cylinders on both sides of the pinch roller, and obtaining oil pressure data of the servo hydraulic cylinders through the hydraulic cylinder oil pressure sensors, respectively calculating the actual force and the actual combined force on one side of the two servo hydraulic cylinders based on the dimensional data and oil pressure data, and obtaining the position data of the pinch roller through the hydraulic cylinder displacement sensors; When the actual resultant force of the two servo hydraulic cylinders deviates from the set resultant force value, the servo valve corresponding to the servo hydraulic cylinder is controlled by the controller arranged on the servo hydraulic cylinder, and the action of the servo hydraulic cylinder is controlled according to the position data of the pinch roller, so as to change the roller gap width of the pinch roller, adjust the actual resultant force value of the servo hydraulic cylinder to the set resultant force value, and keep the resultant force of the two servo hydraulic cylinders constant.

[0009] Preferably, the control object of the controller is the servo hydraulic cylinder, the control source is the hydraulic cylinder oil pressure sensor and the hydraulic cylinder displacement sensor, and the actuator is the servo valve corresponding to the servo hydraulic cylinder.

[0010] Preferably, the servo hydraulic cylinders on both sides of the pinch rollers move synchronously, and the roller gap inclination angle of the pinch rollers remains constant during the movement of the servo hydraulic cylinders.

[0011] Preferably, when the pinch roller is opened with the roller gap inclination angle fixed, the actual resultant force of the two servo hydraulic cylinders decreases, and when the pinch roller is closed with the roller gap inclination angle fixed, the actual resultant force of the two servo hydraulic cylinders increases.

[0012] Compared with the prior art, the present invention has the following beneficial effects: The present invention calculates the unilateral force and the resultant force of the servo hydraulic cylinder by obtaining the size of the servo hydraulic cylinder and the oil pressure data obtained by the oil pressure sensor. When the actual resultant force changes and deviates from the set resultant force value, the controller synchronously adjusts the roller gaps on both sides through the hydraulic cylinder displacement sensor, that is, adjusts the position of the pinch roller up and down while keeping the inclination angle of the pinch roller constant. When the roller gaps on both sides remain tilted and the roller gaps are opened synchronously, the roller gap between the pinch rollers on both sides becomes larger, and the clamping force between the pinch rollers and the pinched material becomes smaller, and the actual resultant force feedback of the hydraulic cylinder is reduced to the set resultant force value. When the roller gaps on both sides remain tilted and the roller gaps are closed synchronously, the roller gap between the pinch rollers on both sides becomes smaller, and the clamping force between the pinch rollers and the pinched material becomes larger, and the actual resultant force feedback of the hydraulic cylinder is increased to the set resultant force value, and the resultant force is constant under the premise of keeping the inclination angle of the pinch roller gap unchanged. Compared with the force control mode of traditional equipment, this force control method can keep the roller gap distance of the pinch roller unchanged when the resultant force of the servo hydraulic cylinder is constant, maintain the stability of the equipment, prevent the material from easily deviating from the pinch roller, and realize stable centerline control of the material. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a flowchart of a force control method with position tilt disclosed in the present invention; Figure 2 Schematic diagram of the same state of the roller gap of the pinch roller of the present invention; Figure 3 This is a schematic diagram of a state in which the roller gap on the A side of the pinch roller of the present invention is smaller than the roller gap on the B side; Figure 4 This is a schematic diagram of the state in which the roller gap on the A side of the pinch roller of the present invention is larger than the roller gap on the B side. DETAILED DESCRIPTION

[0014] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0015] Example: See also Figure 1 - Figure 4 As shown, a force control method with position tilt includes: Obtaining dimensional data of the servo hydraulic cylinders on both sides of the pinch roller, and obtaining oil pressure data of the servo hydraulic cylinders through the hydraulic cylinder oil pressure sensors, respectively calculating the actual force and the actual combined force on one side of the two servo hydraulic cylinders based on the dimensional data and oil pressure data, and obtaining the position data of the pinch roller through the hydraulic cylinder displacement sensors; Based on the width, thickness and tension data of the material to be clamped, the set resultant force value required for clamping the material to be clamped is comprehensively calculated with the addition of the empirical adjustment coefficient of actual production operation. When the actual resultant force of the two servo hydraulic cylinders deviates from the set resultant force value, the servo valve corresponding to the servo hydraulic cylinder is controlled by the controller arranged on the servo hydraulic cylinder, and the servo hydraulic cylinder is controlled to move according to the position data of the pinching roller, so as to change the roller gap width of the pinching roller and adjust the actual resultant force value of the servo hydraulic cylinder to the set resultant force value to keep the resultant force of the two servo hydraulic cylinders constant.

[0016] From the above, it can be seen that the unilateral force and the resultant force of the servo hydraulic rod are calculated by obtaining the size of the servo hydraulic cylinder and the oil pressure data obtained by the oil pressure sensor. When the actual resultant force changes and deviates from the set resultant force value, the controller synchronously adjusts the roller gap on both sides through the hydraulic cylinder displacement sensor, that is, adjusts the position of the pinch roller up and down while keeping the inclination angle of the pinch roller constant. When the actual resultant force value of the two servo hydraulic cylinders is higher than the set resultant force value, the roller gap on both sides remains tilted and the roller gap is opened synchronously, the roller gap between the pinch rollers on both sides becomes larger, the clamping force between the pinch rollers and the pinched material becomes smaller, and the actual resultant force feedback of the hydraulic cylinder is reduced. To the set resultant force value, when the actual resultant force value of the two servo hydraulic cylinders is less than the set resultant force value, the roller gaps on both sides remain tilted and the roller gaps are closed synchronously, the roller gap between the pinch rollers on both sides becomes smaller, and the clamping force between the pinch rollers and the pinched material becomes larger, and the actual resultant force feedback of the hydraulic cylinder is increased to the set resultant force value, and the resultant force is constant under the premise of keeping the inclination angle of the pinch roller gap unchanged. Compared with the traditional equipment force control mode, this force control method can keep the roller gap distance of the pinch roller unchanged when the resultant force of the servo hydraulic cylinder is constant, keep the equipment stable, avoid the material from easily deviating from the pinch roller, and realize stable center line control of the material.

[0017] The control object of the controller is the servo hydraulic cylinder, the control source is the hydraulic cylinder oil pressure sensor and the hydraulic cylinder displacement sensor, and the actuator is the servo valve corresponding to the servo hydraulic cylinder.

[0018] The servo hydraulic cylinders on both sides of the pinch rollers move synchronously, and the roller gap inclination angle of the pinch rollers remains constant during the movement of the servo hydraulic cylinders, regardless of the deviation of the forces on both sides and the deviation between the unilateral force feedback and the setting.

[0019] The surface inclination of the strip to be pinched will cause the pinch rollers attached to the surface of the strip to be pinched to tilt. The tilt angle is set to β, and the β value is recorded by the PLC of the equipment some time before the tail of the strip leaves the continuous rolling mill. During this period, the disturbance between the pinch rollers and the strip is small, the shape of the strip is relatively stable, the speed variation is small, the tension is also stable, and the temperature is relatively uniform, which can reflect the true shape of the strip. At this time, guiding the tail of the strip can effectively prevent the tail from moving due to over-adjustment of the pinch rollers caused by changes in tension, temperature, speed, and plate shape compared to the continuous rolling mill before throwing the steel. When the set value of the position tilt is 0mm, the pinch rollers on the upper and lower sides are parallel and there is no tilt angle. The relative position diagram between the upper and lower rollers is as shown in the figure below. Figure 2 As shown, when the set value of the position tilt is less than 0mm, the upper and lower pinch rollers are no longer parallel, and the upper pinch roller rotates counterclockwise and tilts at an angle of β. The relative position diagram between the upper and lower rollers is shown in Figure 3 As shown, when the set value of the position tilt is greater than 0mm, the upper and lower pinch rollers are no longer parallel, and the upper pinch roller rotates clockwise and tilts at an angle of β. The relative position diagram between the upper and lower rollers is shown in Figure 4 As shown in the figure, keeping the inclination angle of the pinch roller unchanged when the resultant force is constant can not only ensure that the pinch roller has sufficient friction to move the strip, but also avoid the phenomenon that the inclined pinch roller forces the strip to deviate when the resultant force is constant by adjusting the inclination angle of the pinch roller.

[0020] Compared with the traditional force control mode, this mode has obvious advantages under specific circumstances: when the material in the roller gap deviates and gradually tends to direction A, the unilateral force on side A increases and the unilateral force on side B decreases. In the traditional force control mode, the roller gap on side A will open to achieve constant force, and the roller gap on side B will close, which will aggravate the deviation of the material. In the new force control mode, when the combined force of A+B does not change, the roller gap will not move. Since the position tilt is maintained in a stable state, the material will no longer deviate easily, achieving stable centerline control.

[0021] When the pinch rollers are opened with the roller gap inclination angle fixed, the resultant force of the two servo hydraulic cylinders decreases; when the pinch rollers are closed with the roller gap inclination angle fixed, the resultant force of the two servo hydraulic cylinders increases.

[0022] Throughout this specification, references to terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" indicate that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present invention. Throughout this specification, the illustrative expressions of these terms do not necessarily refer to the same embodiment or example. Furthermore, those skilled in the art may combine and integrate different embodiments or examples, and features of different embodiments or examples, described in this specification, unless they conflict with each other.

[0023] In the drawings of the embodiments disclosed in the present invention, only the structures related to the embodiments disclosed in the present invention are involved. Other structures can refer to the general design. In the absence of conflict, the same embodiment and different embodiments of the present invention can be combined with each other.

Claims

1. A force control method with position tilt, characterized in that: include: Obtaining dimensional data of the servo hydraulic cylinders on both sides of the pinch roller, and obtaining oil pressure data of the servo hydraulic cylinders through the hydraulic cylinder oil pressure sensors, respectively calculating the actual force and the actual combined force on one side of the two servo hydraulic cylinders based on the dimensional data and oil pressure data, and obtaining the position data of the pinch roller through the hydraulic cylinder displacement sensors; When the actual resultant force of the two servo hydraulic cylinders deviates from the set resultant force value, the servo valve corresponding to the servo hydraulic cylinder is controlled by the controller arranged on the servo hydraulic cylinder, and the action of the servo hydraulic cylinder is controlled according to the position data of the pinch roller, so as to change the roller gap width of the pinch roller, adjust the actual resultant force value of the servo hydraulic cylinder to the set resultant force value, and keep the resultant force of the two servo hydraulic cylinders constant.

2. A force control method with position tilt according to claim 1, characterized in that: The control object of the controller is the servo hydraulic cylinder, the control source is the hydraulic cylinder oil pressure sensor and the hydraulic cylinder displacement sensor, and the actuator is the servo valve corresponding to the servo hydraulic cylinder.

3. The force control method with position tilt according to claim 1, characterized in that: The servo hydraulic cylinders on both sides of the pinch rollers move synchronously, and the roller gap inclination angle of the pinch rollers remains constant during the movement of the servo hydraulic cylinders.

4. The force control method with position tilt according to claim 1, characterized in that: When the pinch rollers are opened with the roller gap inclination angle fixed, the actual resultant force of the two servo hydraulic cylinders decreases; when the pinch rollers are closed with the roller gap inclination angle fixed, the actual resultant force of the two servo hydraulic cylinders increases.

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