Prestressed steel beam equal-force tensioning control system and using method thereof

Abstract

The invention discloses a prestressed steel beam equal-force tensioning control system and a control method thereof. The system comprises a tensioning device and a tensioning control system, the tensioning device is composed of a front anchorage device, a hydraulic telescopic device and an adjustable anchorage device assembly, an independent cylinder barrel of the hydraulic telescopic device is communicated with a liquid separation device through a hydraulic pipe, and a force sensor and a displacement sensor are installed on a jacking rod; the tension control system adopts a master-slave three-ring PID (Proportion Integration Differentiation) control system, and precise adjustment of force, displacement and time is realized by controlling a valve of a liquid distribution device. When the device is used, the whole steel beam is tensioned in a grading mode, and then single-beam fine adjustment is conducted. The problems that in the prior art, steel beams are uneven in stress, low in control precision and the like are solved, through the three-control PID algorithm and independent hydraulic control, the tensioning accuracy and the construction efficiency are improved, and applicability is high.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of prestressed tensioning in road, bridge and other engineering construction, and more particularly relates to a prestressed steel strand isostatic tensioning control system and a use method thereof. BACKGROUND

[0002] Prestressed tensioning technology is a commonly used technical means in structural engineering such as buildings and bridges. The main purpose of prestressed tensioning is to apply a pre-stress to the structural member to achieve the effect of enhancing the overall performance of the structure and improving safety.

[0003] The traditional prestressed steel strand tensioning technology uses hydraulic telescopic devices in combination with special tensioning equipment to implement staged tensioning of the steel strand, and gradually applies prestress through the "double control method" of stress control as the main and elongation value checking as the auxiliary. However, the traditional prestressed steel strand tensioning technology is whole-beam tensioning, without separate tensioning of individual steel strands in the beam, which can cause uneven stress on each steel strand in the prestressed beam, and can easily cause over-tensioning, under-tensioning, even broken wires and slipped wires, etc., affecting the working performance of the prestressed beam, and in severe cases, can even cause property loss and even personnel casualties. The traditional "double control method" cannot achieve real-time synchronization in the dynamic response of stress control and elongation value checking, resulting in a time difference between the actual state and the theoretical model during prestress application and information disconnection, affecting the judgment of the tensioning condition by the operator and reducing the tensioning quality. In the prior art, the following problems exist: first, the structure is complex, which is not conducive to use and maintenance. Second, the single-beam tensioning hydraulic telescopic device is time-consuming and labor-intensive in the tensioning process, has low construction efficiency and low applicability. The existing technology needs to replace different hydraulic telescopic devices for tensioning different numbers of steel strands, has poor universality, and only has tensioning force as a control parameter, which has low control accuracy and cannot accurately reflect the tensioning condition.

[0004] In view of the above problems, the present application provides a prestressed steel strand isostatic tensioning control system based on master-slave three-loop PID algorithm and a use method thereof. SUMMARY

[0005] In view of the above defects or improvement needs of the prior art, the present application solves the problems of complex steel beam prestressed tensioning structure, low construction efficiency, and low applicability and accuracy in the prior art.

[0006] The present application provides a prestressed steel strand isostatic tensioning control system, comprising: a tensioning device and a tensioning control system.

[0007] The tensioning device comprises a front anchor device at the front end, a hydraulic telescopic device at the middle, and an adjustable anchor assembly at the rear end, and a plurality of clamping hole for multiple steel strands to pass through are arranged in the middle of the front anchor device and the adjustable anchor assembly.

[0008] The hydraulic telescopic device is a double-layered cylindrical hollow body. Its outer layer is divided into multiple independent cylinders. The multiple independent cylinders are connected to the liquid outlet of the liquid distribution device through multiple hydraulic pipes. The hydraulic pipes push the lifting rod by supplying hydraulic oil to the cylinder. The lifting rod is equipped inside the cylinder and a force sensor and a displacement sensor are installed on the lifting rod.

[0009] The adjustable anchor assembly includes a special anchor and a rear anchor, which are arranged overlappingly. The special anchor is disc-shaped and has multiple adjustment holes spaced apart at corresponding positions on the lifting rod for some of the lifting rod to pass through.

[0010] The tension control system includes: a liquid distribution device with multiple liquid outlet valves and a control system; the control system controls the opening and closing degree of the liquid outlet valves of the liquid distribution device via wired or wireless means.

[0011] Furthermore, the liquid separation device includes: a hydraulic power unit and a liquid separator; the hydraulic power unit and the liquid separator are fixedly connected by a pipeline.

[0012] Furthermore, the prestressed steel strand equal-force tensioning control system is characterized in that: the hydraulic power device is an oil pump.

[0013] Furthermore, a limit plate is provided between the front anchor and the hydraulic telescopic device to limit the clamping plate of the front anchor and prevent it from being pulled out by the rigid beam.

[0014] Furthermore, the front anchor, the special anchor, and the rear anchor fix the steel strand by installing clamps in the clamp holes. The clamps restrict the steel strand from contracting inward, but do not restrict the steel strand from stretching outward.

[0015] Furthermore, the materials of the front anchor, the special anchor, and the rear anchor are cast steel.

[0016] Furthermore, the control system adopts a PID control system.

[0017] Furthermore, the PID control system is a master-slave three-loop PID control system, including a master controller and multiple slave controllers. The master controller receives external parameters input by the user, such as the design tension force, theoretical elongation, theoretical tensioning time, and material properties. Based on the real-time data from the force sensor and displacement sensor, it allocates the theoretical tension force and theoretical elongation to the target force F of each slave controller. target and target displacement D target It receives decomposition instructions from the main controller from the controller and independently runs a three-loop PID control system (time loop, displacement loop, and force loop) for real-time adjustment.

[0018] Furthermore, the master-slave three-loop PID control system controls the pulling force by controlling the closing of the distributor valve. The control method is as follows: the time loop receives the global time signal Tsync from the master controller, compares it with the local time Tcurrent, calculates the time error ΔT, and then applies the PID algorithm ΔT... adj =K pt ×ΔT+K it ×∫ΔTdt+K dt ×dΔT / dt, calculate the time compensation amount ΔTadj; the displacement loop combines the target displacement Dtarget with the feedback data Dfeedback from the displacement sensor, and adds the time compensation amount ΔTadj for correction, ΔD=(D target -D feedback )+(1+K t ×ΔT adj ), calculate the displacement error ΔD, and then use the PID algorithm to calculate ΔD adj =K pd ×ΔD+K id ×∫ΔDdt+K dd ×dΔD / dt, calculate the displacement correction ΔDadj and output it to the force loop as a feedforward signal for force adjustment; the force loop is based on the target force Ftarget and the feedback data Ffeedback from the force sensor, and is modified by superimposing the displacement correction ΔDadj, ΔF=(F target -F feedback )+K d ×ΔD adj Calculate the force error ΔF, and then use the PID algorithm to calculate ΔF. adj =K pf ×ΔF+K if ×∫ΔFdt+K df Calculate the force correction ΔFadj using the formula ×dΔF / dt, where the parameter K is... pt K it K dt K t K pd K id K dd K d K pf K if K df As determined by experimental testing, the force correction ΔFadj is converted into the hydraulic valve control signal Uvalve of the distributor, which precisely adjusts the force of the lifting rod.

[0019] As another aspect of the present invention, the present invention also provides: a method for using a prestressed steel strand equal-force tensioning control system, comprising:

[0020] Step 1: Install the tensioned steel strand and wedges in the wedge holes of the front anchor and the special anchor. The control system controls the lifting rod to push the special anchor and the rear anchor with equal force to slowly pressurize the steel strand to the initial stress. Hold the load for 1 to 2 minutes to eliminate the slack of the steel strand.

[0021] Step 2: The control system controls the lifting rod to continue pushing the special anchor and the rear anchor with equal force to tension the steel strand in stages: 20% → 50% → 80%. After each stage of loading, the load is held for 2 to 5 minutes to ensure uniform stress transfer.

[0022] Step 3: After tensioning to 75-85%, the system enters the initial adjustment stage. Select the lifting rod that needs adjustment and input the fine adjustment amount to make the steel strands have similar stress.

[0023] Step 4: After the correction is completed, the control system controls the lifting rod to push the special anchor and the rear anchor to tension to 100%, hold the load for 1-3 minutes, and enter the fine adjustment stage. The actual prestress of each steel strand is read by the sensor to confirm the steel strand that needs to be adjusted, and the single strand adjustment begins.

[0024] Step 5: For under-tensioned steel strands (determined by sensor values), install clamps at the clamp holes of the corresponding rear anchor, lift the lifting rod that can pass through the adjustment hole, apply equal pressure, and push the rear anchor to slowly tension the steel strand to 100%. At the same time, finely adjust the lifting rod of the specially designed lifting anchor to keep the tension of the remaining steel strands unchanged.

[0025] For over-tensioned steel strands, clamps are installed at the clamp holes of the corresponding rear anchors for the remaining steel strands. The lifting rod of the rear anchor is raised to apply pressure until the clamps of the remaining steel strands on the special anchor are just loosened. The lifting rod of the special anchor is controlled to slowly retract until the tension of the steel strand is reduced to 100%.

[0026] Step 6: After adjustment, hold the load for 1-2 minutes, anchor, and retract each lifting rod synchronously to complete the tensioning process.

[0027] In summary, compared with the prior art, the above-described technical solutions conceived by this invention can achieve the following beneficial effects:

[0028] 1. This invention discloses a prestressed steel strand equal-force tensioning control system based on a master-slave three-loop PID algorithm. By replacing the traditional force-displacement dual-control system with a force-displacement-time three-control PID algorithm and incorporating a time parameter, it solves the problems of data lag and misalignment inherent in the force-displacement dual-control system. This improves data accuracy and facilitates tensioning control. Furthermore, by compensating for historical errors through time integration and dynamically adjusting the tensioning speed, it addresses the problem of relying on experience to control the tensioning speed in traditional tensioning methods, which negatively impacts tensioning quality.

[0029] 2. The present invention provides a prestressed steel strand equal-force tensioning control system based on a master-slave three-loop PID algorithm. By using a multi-part hydraulic telescopic device, each part of the hydraulic system is made independent and can be adjusted differently. This solves the problem of uneven stress distribution caused by the overall tensioning of traditional hydraulic telescopic devices. Furthermore, the individual control from the controller allows the tensioning speed of each lifting rod to be adjusted independently, making fine-tuning more flexible. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the tensioning process of the prestressed steel strand equal force tensioning control system according to an embodiment of the present invention;

[0031] Figure 2 This is a simplified installation diagram of the device according to an embodiment of the present invention;

[0032] Figure 3 This is a cross-sectional view of the hydraulic telescopic device according to an embodiment of the present invention (solid arrows indicate the flow direction of hydraulic oil, and hollow arrows indicate the lifting direction of the lifting rod).

[0033] Figure 4 This is a rear view of the hydraulic telescopic device according to an embodiment of the present invention;

[0034] Figure 5 This is a front view of the hydraulic telescopic device according to an embodiment of the present invention;

[0035] Figure 6 This is a vertical cross-sectional view of the hydraulic telescopic device according to an embodiment of the present invention;

[0036] Figure 7 A front view of a specially made anchor for an embodiment of the present invention;

[0037] Figure 8 This is a control flowchart of an embodiment of the present invention;

[0038] Figure 9 Flowcharts of time loop, displacement loop, and force loop control in embodiments of the present invention;

[0039] In all the accompanying drawings, the same reference numerals denote the same technical features, specifically: 1-front anchor; 2-limiting plate; 3-clamping plate; 4-six-part hydraulic telescopic device; 41-cylinder; 42-lifting rod; 421-lifting rod No. 1; 422-lifting rod No. 2; 423-lifting rod No. 3; 424-lifting rod No. 4; 425-lifting rod No. 5; 426-lifting rod No. 6; 5-special anchor; 50-clamping plate hole; 51-hole No. 1; 52-hole No. 2; 53-hole No. 3; 6-rear anchor; 7-prestressed steel strand; 8-hydraulic pipe; 9-main controller; 10-slave controller; 11-hydraulic power unit; 12-liquid distributor; 13-master-slave three-loop PID control system; 14-tensioning device; 15-liquid distributor. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0041] Please refer to Figure 1 , Figure 2 Taking a six-part hydraulic telescopic device (six cylinders and six lifting rods) as an example: a prestressed steel strand equal force tensioning control system includes: a tensioning control system and a tensioning device;

[0042] The tension control system includes: a liquid distribution device 15 with multiple liquid outlet valves and a PID control system 13; the PID control system 13 controls the opening and closing degree of the liquid outlet valves of the liquid distribution device 15 via wired or wireless means.

[0043] The liquid separation device 15 includes a hydraulic power unit 11 and a liquid separator 12; the hydraulic power unit 11 (preferably an oil pump) and the liquid separator 12 are fixedly connected by a pipeline.

[0044] Please refer to Figure 1 , Figure 3 , Figure 5 , Figure 6 The tensioning device 14 includes: a front anchor 1 at the front end, a hydraulic telescopic device 4 in the middle, and an adjustable anchor assembly at the rear end.

[0045] The hydraulic telescopic device 4 is a double-layered cylindrical hollow body. Its outer layer is divided into multiple independent cylinders 41. The multiple independent cylinders 41 are connected to the outlet of the liquid distribution device 15 through multiple hydraulic pipes 8. The hydraulic pipes 8 push the lifting rod 42 by supplying hydraulic oil to the cylinders 41. The lifting rod 42 is installed inside the cylinders 41. Force sensor and displacement sensor are installed on the lifting rod 42.

[0046] Preferably, a limiting plate 2 is added between the front anchor 1 and the hydraulic telescopic device 4 to limit the clamping piece 3 of the front anchor 1 and prevent it from being pulled out by the rigid beam.

[0047] Please refer to Figure 7 The adjustable anchor assembly includes a special anchor 5 and a rear anchor 6, which are arranged in an overlapping manner. The special anchor 5 is disc-shaped and has multiple adjustment holes spaced apart at corresponding positions of the lifting rod 42 for some of the lifting rod 42 to pass through. That is, after some of the lifting rod 42 passes through the adjustment holes, it pushes the rear anchor 6, while other lifting rod 42, since there are no adjustment holes at corresponding positions, can push the special anchor 5.

[0048] Both the front anchor 1 and the adjustable anchor assembly are provided with multiple clamping holes 50 for multiple steel strands 7 to pass through.

[0049] The front anchor 1, the special anchor 5, and the rear anchor 6, through the wedge-shaped self-locking effect of the clamping plates 3 installed in the clamping plate holes, restrict the inward contraction of the steel strand while not restricting its outward stretching. Other locking devices can also be used for fixation.

[0050] The front anchor 1, the special anchor 5, the rear anchor 6, and the wedge 3 are preferably made of cast steel.

[0051] Please refer to Figure 8 , Figure 9 The master-slave three-loop PID control system consists of a master controller and six slave controllers. The master controller receives user-inputted external parameters such as design tension force, theoretical elongation, theoretical tensioning time, and material properties. Based on real-time data from force and displacement sensors, it allocates the theoretical tension force and theoretical elongation to the target force F of each slave controller. target and target displacement D target The controller receives decomposed commands from the main controller and independently runs a three-loop PID control system (time loop, displacement loop, and force loop) for real-time adjustment. The time loop receives the global time signal T from the main controller. sync Compare with local time T current Calculate the time error ΔT, and then use the PID algorithm to calculate ΔT. adj =K pt ×ΔT+K it ×∫ΔTdt+K dt Calculate the time compensation amount ΔT using ×dΔT / dt. adj Used to constrain the movement rhythm of the displacement loop and force loop, eliminating the asynchronous problem of multiple lifting rods. The displacement loop is combined with the target displacement D. target Feedback data D from the displacement sensor feedback And add time compensation amount ΔT adj Correction, ΔD=(D target -D feedback )+(1+K t ×ΔT adj ), calculate the displacement error ΔD, and then use the PID algorithm to calculate ΔD adj =K pd ×ΔD+K id ×∫ΔDdt+K dd Calculate the displacement correction ΔD using ×dΔD / dt. adj The output is sent to the force loop as a feedforward signal for internal regulation. The force loop is based on the target force F. target Feedback data F from the force sensor feedback And superimposed displacement correction ΔD adj Correction, ΔF=(F target-F feedback )+K d ×ΔD adj Calculate the force error ΔF, and then use the PID algorithm to calculate ΔF. adj =K pf ×ΔF+K if ×∫ΔFdt+K df Calculate the force correction ΔF using ×dΔF / dt. adj Force correction ΔF adj Converted into hydraulic valve control signal U valve The force of the lifting rods is precisely adjusted to ensure balanced tension of the steel strands. This master-slave three-loop PID algorithm performs real-time calculations and can dynamically and independently adjust the tension of each lifting rod.

[0052] Wherein, parameter K pt K it K dt K t K pd K id K dd K d K pf K if K df This can be obtained through experimental testing. Furthermore, the time variable ensures a one-to-one correspondence between the displacement and force signals fed back by the sensor, avoiding data misalignment issues.

[0053] Preferably, parameter K pt K it K dt K t K pd K id K dd K d K pf K if K df This can be achieved through multiple simulations using digital twin or BIM technology. By embedding FBG fiber optic sensors in specially designed anchorages, the prestress distribution of individual steel strands is precisely detected and fed back to the model for multiple simulations to obtain parameter values. Compared to the parameter values ​​obtained through testing, these values ​​have smaller errors. Simultaneously, incorporating digital twin technology into the tensioning process for real-time simulation calculations allows for early prediction of tensioning conditions, facilitating adjustments and prevention of potential problems.

[0054] Preferably, a routine judgment procedure for the relationship between force and pulling distance is added to the PID algorithm. When an abnormal relationship is detected, the system immediately triggers an emergency shutdown, personnel are evacuated immediately, and pressure is released to prevent accidents.

[0055] How to use:

[0056] 1. Install force sensors and displacement sensors on the lifting rod 42. Connect the hydraulic telescopic device 4 to the distributor 12 through the hydraulic pipe 8. The distributor 12 is connected to the hydraulic power unit 11, such as an oil pump. The master-slave three-loop PID control system 13 is connected to the distributor 12 and controls the valve of the distributor 12.

[0057] 2. Thread the steel strands through the cable, install the front anchor 1 and clamp 3, install the matching limiting plate 2, install the sensor, install the six-part hydraulic telescopic device 4, and install the special anchor 5 and clamp 3, so that holes 1 (51), 2 (52), and 3 (53) correspond to lifting rod 1 (421), lifting rod 3 (423), and lifting rod 5 (425) respectively; lifting rod 1 (421), lifting rod 3 (423), and lifting rod 5 (425) can pass through holes 1 (51), 2 (52), and 3 (53). Install the rear anchor 6. Input the design tension force, theoretical elongation, tensioning time, and steel strand material properties into the main controller.

[0058] 3 sheets.

[0059] ① Use lifting rods 422, 424, and 426 to slowly apply pressure to push the special anchor 5 until the initial stress is 10%, hold the load for 1-2 minutes, and eliminate the slack in the steel strand.

[0060] ② The No. 2 lifting rod 422, the No. 4 lifting rod 424, and the No. 6 lifting rod 426 apply equal pressure to push the specially made anchor 5 for graded tensioning. The graded tensioning is: 20% → 50% → 80%. After each grade of loading, the load is held for 2 to 5 minutes to ensure uniform stress transmission.

[0061] ③ After tensioning to about 80%, the system enters the initial adjustment stage. Select the lifting rod that needs to be adjusted through the touch screen and input the fine adjustment amount to make the steel strands have similar stress and prevent the stress difference from being too large after tensioning.

[0062] ④ After the correction is completed, the No. 2 lifting rod 422, the No. 4 lifting rod 424, and the No. 6 lifting rod 426 apply equal pressure to push the special anchor 5, tensioning the steel strand to 100%, holding the load for 2 minutes, and entering the fine adjustment stage. The actual prestress of each steel strand is read through the sensor to confirm the steel strand that needs to be adjusted, and the single strand adjustment begins.

[0063] ⑤ After sensor detection, for under-tensioned steel strands, clamps are installed on the clamp holes at the rear anchor 6 where the under-tensioned steel strand passes through. Lifting rods 421, 423, and 425 apply pressure to push the rear anchor so that the steel strand is slowly tensioned to 100%. At the same time, lifting rods 422, 424, and 426 are finely adjusted to keep the tension of the remaining steel strands constant.

[0064] After sensor detection, for the over-tensioned steel strand, clamps are installed at the clamp holes of the remaining steel strands' rear anchorages. Lifting rods 421, 423, and 425 apply pressure to push the rear anchorages until the clamps of the remaining steel strands on the special anchorages just loosen. Lifting rods 422, 424, and 426 slowly retract, causing the special anchorages to retract as well. At this time, the retraction effect only acts on the over-tensioned steel strand and does not affect the steel strands that have been fixed by the rear anchorage 6, until the tension of the over-tensioned steel strand is reduced to 100%.

[0065] ⑥ After adjustment, hold the load for 1-2 minutes, anchor, and retract each lifting rod synchronously to complete the tensioning process. Finally, disassemble each device and check for wear.

[0066] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A prestressed steel strand equal-force tensioning control system, comprising: Tensioning device (14), tensioning control system; The tensioning device includes: a front anchor (1) at the front end, a hydraulic telescopic device (4) in the middle, and an adjustable anchor assembly at the rear end. The front anchor (1) and the adjustable anchor assembly are provided with multiple clamping holes for multiple steel strands (7) to pass through in the middle. The hydraulic telescopic device (4) is a double-layered cylindrical hollow body, the outer layer of which is divided into multiple independent cylinders (41). The multiple independent cylinders (41) are connected to the outlet of the liquid distribution device (15) through multiple hydraulic pipes (8). The hydraulic pipes (8) push the lifting rod (42) by supplying hydraulic oil to the cylinders (41). The lifting rod (42) is provided inside the cylinder (41), and a force sensor and a displacement sensor are installed on the lifting rod (42). The adjustable anchor assembly includes a special anchor (5) and a rear anchor (6), which are arranged in an overlapping manner; the special anchor (5) is disc-shaped, and multiple adjustment holes are spaced apart at the corresponding positions of the lifting rod (42) for part of the lifting rod (42) to pass through; The tension control system includes: a liquid distribution device (15) with multiple liquid outlet valves and a control system (13); the control system (13) controls the opening and closing degree of the liquid outlet valves of the liquid distribution device by wired or wireless means.

2. The prestressed steel strand equal-force tensioning control system according to claim 1, characterized in that, The liquid separation device (15) includes: a hydraulic power unit (11) and a liquid separator (12); the hydraulic power unit (11) and the liquid separator (12) are fixedly connected by a pipeline.

3. The prestressed steel strand equal-force tensioning control system according to claim 1, characterized in that: The hydraulic power unit (11) is an oil pump.

4. The prestressed steel strand equal-force tensioning control system according to claim 1, characterized in that, A limiting plate (2) is also provided between the front anchor (1) and the hydraulic telescopic device (4) to limit the clamping piece (3) of the front anchor (1) and prevent it from being pulled out by the rigid beam.

5. The prestressed steel strand equal-force tensioning control system according to claim 1, characterized in that, The front anchor (1), the special anchor (5), and the rear anchor (6) fix the steel strand by installing clamps (3) in the clamp holes. The clamps (3) restrict the steel strand from contracting inward, but do not restrict the steel strand from stretching outward.

6. The prestressed steel strand equal-force tensioning control system according to claim 1, characterized in that, The front anchor (1), the special anchor (5), and the rear anchor (6) are made of cast steel.

7. The prestressed steel strand equal-force tensioning control system according to claim 1, characterized in that, The control system (13) adopts a PID control system.

8. The prestressed steel strand equal-force tensioning control system according to claim 7, characterized in that, The PID control system is a master-slave three-loop PID control system (13), including a master controller and multiple slave controllers. The master controller receives external parameters such as design tension force, theoretical elongation, theoretical tensioning time, and material properties input by the user. Based on the real-time data from the force sensor and displacement sensor, it allocates the theoretical tension force and theoretical elongation to the target force F of each slave controller. target and target displacement D target It receives decomposition instructions from the main controller from the controller and independently runs a three-loop PID control system (time loop, displacement loop, and force loop) for real-time adjustment.

9. A prestressed steel strand equal-force tensioning control system according to claim 8, characterized in that: The control system (13) controls the pulling force by controlling the closing of the valve of the distributor (12). The control method is as follows: the time loop receives the global time signal Tsync from the main controller, compares it with the local time Tcurrent, calculates the time error ΔT, and then uses the PID algorithm ΔT adj =K pt ×ΔT+K it ×∫ΔTdt+K dt ×dΔTdt, calculate the time compensation amount ΔTadj; The displacement loop combines the target displacement Dtarget with the feedback data Dfeedback from the displacement sensor, and adds a time compensation amount ΔTadj for correction, ΔD=(D target -D feedback )+(1+K t ×ΔT adj ), calculate the displacement error ΔD, and then use the PID algorithm to calculate ΔD adj =K pd ×ΔD+K id ×∫ΔDdt+K dd The displacement correction ΔDadj is calculated by multiplying ×dΔDdt and output to the force loop as a feedforward signal for force adjustment. The force loop is based on the target force Ftarget and the feedback data Ffeedback from the force sensor, and is superimposed with a displacement correction ΔDadj, ΔF=(F target -F feedback )+K d ×ΔD adj Calculate the force error ΔF, and then use the PID algorithm to calculate ΔF. adj =K pf ×ΔF+K if ×∫ΔFdt+K df ×dΔFdt, calculate the force correction ΔFadj, where the parameter K pt K it K dt K t K pd K id K dd K d K pf K if K df The force correction ΔFadj is converted into the hydraulic valve control signal Uvalve of the distributor (12) to precisely adjust the force of the lifting rod (42).

10. A method for using a prestressed steel strand equal-force tensioning control system, characterized in that, include: Step 1: Install clamps (3) in the clamp holes of the front anchor (1) and the special anchor (5). The control system (13) controls the lifting rod (42) to push the special anchor (5) and the rear anchor (6) with equal force to slowly pressurize the steel strand to the initial stress. Hold the load for 1 to 2 minutes to eliminate the slack of the steel strand. Step 2: The control system (13) controls the lifting rod (42) to continue to push the special anchor (5) and the rear anchor (6) with equal force to perform graded tensioning of the steel strand as a whole. The graded tensioning is: 20% → 50% → 80%. After each grade of loading, the load is held for 2 to 5 minutes to ensure uniform stress transmission. Step 3: After tensioning to 75-85%, the system enters the initial adjustment stage. Select the lifting rod (42) that needs adjustment and input the fine adjustment amount to make the steel strands have similar stress. Step 4: After the correction is completed, the control system (13) controls the lifting rod (42) to push the special anchor (5) and the rear anchor (6) to tension to 100%, hold the load for 1-3 minutes, and enter the fine adjustment stage. The actual prestress of each steel strand is read by the sensor to confirm the steel strand that needs to be adjusted and start single strand adjustment. Step 5: For under-tensioned steel strands, install clamps (3) on the clamp holes at the rear anchor (6) where the under-tensioned steel strand passes through, lift the lifting rod (42) that can pass through the adjustment hole, apply equal pressure, and push the rear anchor (6) to slowly tension the under-tensioned steel strand to 100%. At the same time, finely adjust the lifting rod (42) of the remaining lifting special anchors (5), that is, the part of the lifting rod (42) that cannot pass through the adjustment hole, so that the tension of the remaining steel strands remains unchanged. For the over-tensioned steel strand, install the clamps (3) at the clamp holes of the corresponding rear anchor (6) of the other steel strands, and pressurize the lifting rod (42) of the lifting rear anchor until the clamps of the other steel strands on the special anchor (5) are just loosened. Control the lifting rod (42) of the special anchor (5) to slowly retract. At this time, the retraction effect only acts on the over-tensioned steel strand until the tension of the over-tensioned steel strand is reduced to 100%. Step 6: After adjustment, hold the load for 1-2 minutes, anchor, and retract each lifting rod (42) synchronously to complete the tensioning process.

Images