Wide-displacement pump control system giving consideration to high-speed duct piece movement and high-precision duct piece butt joint and control method of wide-displacement pump control system

Abstract

The invention relates to the technical field of shield segment assembly hydraulic control, and discloses a wide-displacement pump control system giving consideration to high-speed segment transfer and high-precision segment butt joint and a control method thereof.The system adopts a large-displacement pump and a small-displacement pump which are connected in parallel and are driven by servo motors correspondingly, and the large-displacement pump and the small-displacement pump are converged into a main oil way through a one-way valve; and the three-position four-way reversing valve distributes to an execution element. Each execution element is controlled by an independent switch valve group and a pilot-operated type balance valve, and it is ensured that unit elements work to avoid flow disturbance. The control system dynamically distributes the double-pump output proportion according to the target flow: a double-pump joint mode is started during high-speed transfer, a small-displacement pump is preferentially used for quick response in the initial stage, and then a large-displacement pump is switched for leading; and only the small-displacement pump is started during high-precision butt joint. Through a dynamic flow distribution strategy, the segment assembling efficiency, the control precision and the movement stability are remarkably improved, and the synchronous requirements of large-flow high-speed moving and micro-flow precise posture adjustment are met.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of shield segment assembly hydraulic control, and particularly relates to a wide-displacement pump control system and a control method thereof which take into account high-speed segment moving and high-precision segment butt joint. BACKGROUND

[0002] After tunnel excavation is completed by a shield, the tunnel wall needs to be supported by building a lining, and the lining is composed of a plurality of segments distributed along the circumference of the tunnel. As an important component of the shield tunneling machine, the main function of the segment erector is to move the segments to the target position in a specific attitude to form the lining. Each segment has a specific position and attitude, so the segment erector usually needs to complete a plurality of degrees of freedom movements to complete the segment moving work. Since a tunnel lining is usually composed of a large number of segments, and the segment installation precision affects the load-bearing capacity of the lining and the sealing between the segments, the segment assembly precision and speed directly affect the efficiency and quality of tunnel construction. Segment assembly includes two-stage movement of large-range fast moving segment moving (translation, lifting, rotation) and small-range precise fine-tuning (deflection, forward and backward pitching, left and right swinging), and a system form of an oil inlet throttling speed control valve controlled motor and a valve controlled hydraulic cylinder is usually adopted.

[0003] In the actual segment assembly process, the segment moving flow demand is large and the precise fine-tuning flow demand is small, which shows that the overall flow demand span is extremely large. Purely relying on throttling control will cause large energy loss. The pump control hydraulic system does not have throttling loss and throttling loss because of using volume control method, and can match power from the power source of the electro-hydraulic system to realize high energy efficiency. The electro-hydraulic system of the shield segment assembly generally adopts a single electric proportional variable pump matched with a variable frequency motor as the power source. However, under the condition of fixed displacement or fixed motor speed, it is quite challenging to use a single pump to realize precise motion control and maintain fast response capability in the full flow range, mainly for the following reasons: 1) a small displacement pump has relatively fast response speed and control precision, but cannot meet the large flow demand under normal working conditions of the segment erector, resulting in slow moving speed and low efficiency during segment moving; 2) a large displacement pump has a large flow range, but due to its slow response speed and large controllable minimum flow, it cannot realize fast response and high assembly precision requirements of the segment erector when used alone. SUMMARY

[0004] The purpose of the present application is to provide a wide-displacement pump control system and a control method thereof which take into account high-speed segment moving and high-precision segment butt joint, by considering the control interval in which the pump control unit performs best, combining high-precision control of the small displacement pump and high-speed movement of the large displacement pump, building a set of dual-pump joint control electro-hydraulic system, realizing precise motion and fast response in the full flow range, and meeting the performance requirements of high-speed moving and high-precision butt joint of the segment erector.

[0005] To achieve the above object, the technical scheme adopted is as follows:

[0006] In a first aspect, the application provides a wide-displacement pump control system that takes into account high-speed pipe piece transfer and high-precision pipe piece butt joint, comprising:

[0007] An oil tank for storing hydraulic oil;

[0008] A large-displacement pump and a small-displacement pump arranged in parallel, driven by a servo motor one and a servo motor two respectively, the inlets of the large-displacement pump and the small-displacement pump are connected to the oil tank through an oil return filter one and an oil return filter two, and the outlets of the large-displacement pump and the small-displacement pump are connected to a main oil supply pipeline through a one-way valve one and a one-way valve two;

[0009] A three-position four-way reversing valve, the P port of which is connected to the main oil supply pipeline, the T port is connected to an oil return filter three, and the A port and the B port are connected to an execution element group;

[0010] An execution element group, comprising a plurality of execution elements, each execution element comprising a hydraulic cylinder, a switch valve and a pilot balanced valve, the execution element is connected to the A port and the B port of the three-position four-way reversing valve through the pilot balanced valve, and the two groups of switch valves and one pilot balanced valve are used to independently control the action of the execution element;

[0011] A control system for dynamically allocating the output proportion of the large-displacement pump and the small-displacement pump according to the target flow, and adopting a double-pump combined mode during pipe piece transfer and a small-displacement pump independent mode during pipe piece butt joint.

[0012] Preferably, in the wide-displacement pump control system that takes into account high-speed pipe piece transfer and high-precision pipe piece butt joint, the execution element group comprises six execution elements, namely a first execution element, a second execution element, a third execution element, a fourth execution element, a fifth execution element and a sixth execution element; wherein:

[0013] The first execution element comprises a swing hydraulic cylinder, a switch valve one, a switch valve two and a pilot balanced valve one;

[0014] The second execution element comprises a pitch hydraulic cylinder, a switch valve three, a switch valve four and a pilot balanced valve two;

[0015] The third execution element comprises a roll hydraulic cylinder, a switch valve five, a switch valve six and a pilot balanced valve three;

[0016] The fourth execution element comprises a lifting hydraulic cylinder, a switch valve seven, a switch valve eight and a pilot balanced valve four;

[0017] The fifth execution element comprises a transverse movement hydraulic cylinder, a switch valve nine, a switch valve ten and a pilot balanced valve five;

[0018] The sixth execution element includes switch valve eleven, switch valve twelve, pilot balanced valve six and hydraulic motor.

[0019] Preferably, in the above-mentioned wide-displacement pump control system which takes into account both high-speed pipe piece moving and high-precision pipe piece butt joining, the A port of the three-position four-way directional valve is connected to the D port of the first pilot balanced valve, the D port of the second pilot balanced valve, the D port of the third pilot balanced valve, the D port of the fourth pilot balanced valve, the D port of the fifth pilot balanced valve and the D port of the sixth pilot balanced valve, and the B port of the three-position four-way directional valve is connected to the C port of the first pilot balanced valve, the C port of the second pilot balanced valve, the C port of the third pilot balanced valve, the C port of the fourth pilot balanced valve, the C port of the fifth pilot balanced valve and the C port of the sixth pilot balanced valve.

[0020] The A port of the switch valve one is connected to the B port of the first pilot balanced valve, and the B port is connected to the B port of the swing hydraulic cylinder; the A port of the switch valve two is connected to the A port of the first pilot balanced valve, and the B port is connected to the A port of the swing hydraulic cylinder.

[0021] The A port of the switch valve three is connected to the B port of the second pilot balanced valve, and the B port is connected to the B port of the pitch hydraulic cylinder; the A port of the switch valve four is connected to the A port of the second pilot balanced valve, and the B port is connected to the A port of the pitch hydraulic cylinder.

[0022] The A port of the switch valve five is connected to the A port of the third pilot balanced valve, and the B port is connected to the B port of the roll hydraulic cylinder; the A port of the switch valve six is connected to the A port of the third pilot balanced valve, and the B port is connected to the A port of the roll hydraulic cylinder.

[0023] The A port of the switch valve seven is connected to the B port of the fourth pilot balanced valve, and the B port is connected to the B port of the lift hydraulic cylinder; the A port of the switch valve eight is connected to the A port of the fourth pilot balanced valve, and the B port is connected to the A port of the lift hydraulic cylinder.

[0024] The A port of the switch valve nine is connected to the B port of the fifth pilot balanced valve, and the B port is connected to the B port of the traverse hydraulic cylinder; the A port of the switch valve ten is connected to the A port of the fifth pilot balanced valve, and the B port is connected to the A port of the traverse hydraulic cylinder.

[0025] The A port of the switch valve eleven is connected to the B port of the sixth pilot balanced valve, and the B port is connected to the hydraulic motor; the A port of the switch valve twelve is connected to the A port of the sixth pilot balanced valve, and the B port is connected to the hydraulic motor.

[0026] Preferably, in the above-mentioned wide-displacement pump control system that takes into account both high-speed pipe piece moving and high-precision pipe piece butt joint, in the double-pump combined mode, the control system controls the lifting hydraulic cylinder, the horizontal moving hydraulic cylinder and the hydraulic motor; when controlling the lifting hydraulic cylinder, switch valve seven and switch valve eight are in the right position, and all the other two switch valves of the execution elements are in the left position; when the lifting hydraulic cylinder is pushed out, the three-position four-way directional valve is in the right position, hydraulic oil flows in through the P port of the three-position four-way directional valve and flows out through the B port, enters the B port of the lifting hydraulic cylinder through switch valve seven; when the lifting hydraulic cylinder is retracted, the three-position four-way directional valve is in the left position, hydraulic oil flows in through the P port of the three-position four-way directional valve and flows out through the A port, enters the A port of the lifting hydraulic cylinder through switch valve eight; the two switch valves corresponding to the lifting hydraulic cylinder, the horizontal moving hydraulic cylinder and the hydraulic motor are controlled in turn to realize the lifting and horizontal moving actions of the pipe piece, thereby realizing the high-speed moving of the pipe piece.

[0027] Preferably, in the above-mentioned wide-displacement pump control system that takes into account both high-speed pipe piece moving and high-precision pipe piece butt joint, in the small-displacement pump independent mode, the control system controls the swing hydraulic cylinder, the pitch hydraulic cylinder and the roll hydraulic cylinder; when controlling the swing hydraulic cylinder, switch valve one and switch valve two are in the right position, and all the other two switch valves of the execution elements are in the left position; when the swing hydraulic cylinder is pushed out, the three-position four-way directional valve is in the right position, hydraulic oil flows in through the P port of the three-position four-way directional valve and flows out through the B port, enters the B port of the swing hydraulic cylinder through switch valve one; when the swing hydraulic cylinder is retracted, the three-position four-way directional valve is in the left position, hydraulic oil flows in through the P port of the three-position four-way directional valve and flows out through the A port, enters the A port of the swing hydraulic cylinder through switch valve two; the two switch valves corresponding to the swing hydraulic cylinder, the pitch hydraulic cylinder and the roll hydraulic cylinder are controlled in turn to realize the swing, pitch and roll actions of the pipe piece, thereby realizing the high-precision butt joint of the pipe piece.

[0028] Preferably, in the above-mentioned wide-displacement pump control system that takes into account both high-speed pipe piece moving and high-precision pipe piece butt joint, the control system comprises a mode controller, which determines the double-pump working mode based on the target flow rate:

[0029] When the target flow rate is less than a set threshold value, only the small-displacement pump is enabled to output the high-precision flow rate;

[0030] When the target flow rate is greater than or equal to the set threshold value, the double-pump combined mode is enabled, and the small-displacement pump is preferentially used for output within a preset switching time, and then the large-displacement pump is switched to be the dominant output.

[0031] Preferably, in the above-mentioned wide-displacement pump control system that takes into account both high-speed pipe piece moving and high-precision pipe piece butt joint, in the double-pump combined mode, the flow rate output ratio of the small-displacement pump to the large-displacement pump is 9:1 before the preset switching time and is adjusted to 4:6 after the preset switching time.

[0032] Preferably, in the wide-displacement pump control system that takes into account both high-speed segment moving and high-precision segment jointing, the control system comprises an expert recommendation system, the expert recommendation system is configured with a database, the database stores a mapping relationship between input parameters and output parameters, the mapping relationship between the input parameters and the output parameters is established through a machine learning algorithm, the machine learning algorithm is a back propagation neural network or a nearest neighbor algorithm, the input parameters are segment specifications, small pump displacement, large pump displacement, lifting hydraulic cylinder specifications, transverse moving hydraulic cylinder specifications, swinging hydraulic cylinder specifications, pitching hydraulic cylinder specifications, rolling hydraulic cylinder specifications, and hydraulic motor specifications, and the output parameters include preset switching time, switching flow, small pump and large pump flow output ratio, and small pump and large pump flow output ratio.

[0033] In a second aspect, the application provides a control method of a wide-displacement pump control system that takes into account both high-speed segment moving and high-precision segment jointing, the control method comprises:

[0034] determining the working mode according to the target flow: if the target flow is a high flow demand, entering a double-pump joint control mode; if it is a low flow demand, entering a small-displacement pump independent mode;

[0035] in the double-pump joint mode, controlling the small-displacement pump and the large-displacement pump to output flow according to a preset ratio, and adjusting the ratio after a preset switching time;

[0036] selecting the execution element of the current action through the switch valve group to ensure that only one execution element works at a time;

[0037] real-time acquisition of execution element displacement data, correction of the double-pump output ratio through a closed-loop control algorithm, and ensuring that the displacement tracking error is less than a set threshold.

[0038] Further, the closed-loop control algorithm is a PID control, an adaptive control, or a robust control.

[0039] The application has the following beneficial effects:

[0040] 1) The application meets the dual requirements of high-speed segment moving and high-precision segment jointing of a segment erector through a double-pump parallel design and a double-pump flow dynamic distribution strategy. In the wide-displacement control system of the segment erector, the parameters in the dynamic distribution strategy can form a control parameter database, and an expert recommendation system can be established through a machine learning algorithm to provide guidance for the wide-displacement pump control segment automatic erector;

[0041] 2) The application uses a parallel double-variable speed pump control system as the power source of the segment erector to meet the wide-displacement control requirements of the segment erector for high-speed segment moving and high-precision segment jointing;

[0042] 3) The application does not need to carry a throttling type valve control module, and through the form of switch valve group, avoids the pressure flow disturbance caused by the simultaneous movement of different executing elements during the pipe piece moving and splicing process, greatly improves the control accuracy, movement stability and system energy efficiency;

[0043] 4) The application can adjust the switching of single small displacement pump and double pump control modes, the flow output ratio switching and switching time of small displacement pump and large displacement pump in double pump control mode in real time, greatly improves the control accuracy and dynamic response ability of the system;

[0044] 5) The application establishes a control parameter database of wide flow double pump control system and an expert recommendation system, can recommend various control parameters of double pump dynamic distribution strategy in real time, realizes the automatic control of pipe piece splicing machine without manual operation. BRIEF DESCRIPTION OF DRAWINGS

[0045] Figure 1 A structure schematic diagram of a wide displacement pump control system considering high-speed pipe piece moving and high-precision pipe piece splicing according to an embodiment of the application is shown.

[0046] Figure 2 A working principle diagram of a control system in a wide displacement pump control system considering high-speed pipe piece moving and high-precision pipe piece splicing according to an embodiment of the application is shown.

[0047] REFERENCE NUMERALS:

[0048] 1 - oil tank; 2 - oil return filter one; 3 - oil return filter two; 4 - servo motor two; 5 - small displacement pump; 6 - servo motor one; 7 - large displacement pump; 8 - check valve one; 9 - check valve two; 10 - overflow valve; 11 - liquid level and temperature gauge; 12 - oil return filter three; 13 - three-position four-way reversing valve; 14 - swing hydraulic cylinder; 15 - switch valve one; 16 - switch valve two; 17 - pilot balanced valve one; 18 - pitch hydraulic cylinder; 19 - switch valve three; 20 - switch valve four; 21 - pilot balanced valve two; 22 - roll hydraulic cylinder; 23 - switch valve five; 24 - switch valve six; 25 - pilot balanced valve three; 26 - lifting hydraulic cylinder; 27 - switch valve seven; 28 - switch valve eight; 29 - pilot balanced valve four; 30 - transverse moving hydraulic cylinder; 31 - switch valve nine; 32 - switch valve ten; 33 - pilot balanced valve five; 34 - switch valve eleven; 35 - switch valve twelve; 36 - pilot balanced valve six; 37 - hydraulic motor. DETAILED DESCRIPTION

[0049] The following describes the embodiments of the present application through specific examples. Those skilled in the art can easily understand the other advantages and effects of the present application from the content disclosed in this specification. The present application can also be implemented or applied through other different specific embodiments. The details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that the following embodiments and features in the embodiments can be combined with each other unless they conflict.

[0050] The specific implementation of the present application is further described in detail below with reference to the accompanying drawings and examples.

[0051] Example 1:

[0052] The embodiment of the present application provides a wide displacement pump control system that takes into account both high-speed segment movement and high-precision segment docking. Figure 1 As shown, the wide-displacement pump control system that takes into account both high-speed segment movement and high-precision segment docking includes an oil tank 1, a large-displacement pump 7, a small-displacement pump 5, a three-position four-way reversing valve 13, an actuator group and a control system. The oil tank 1 is used to store hydraulic oil, and the oil tank 1 is matched with a liquid level and temperature gauge 11; the large-displacement pump 7 and the small-displacement pump 5 arranged in parallel are driven by a servo motor 1 6 and a servo motor 2 4 respectively, and the inlets of the large-displacement pump 7 and the small-displacement pump 8 are connected to the oil tank through the return oil filter 1 2 and the return oil filter 2 3 pipelines, and the outlets of the large-displacement pump 7 and the small-displacement pump 5 are merged into the main oil supply pipeline through the one-way valve 1 8 and the one-way valve 2 9; the three-position four-way reversing valve 13 is connected to the main oil supply pipeline. The P port is connected to the main oil supply pipeline, the T port is connected to the return oil filter 3 12, and the A port and the B port are connected to the actuator group through multiple pilot balancing valves respectively; the actuator group includes multiple actuators, each actuator includes a hydraulic cylinder, a switch valve and a pilot balancing valve, and the actuator is connected to the A port and the B port of the three-position four-way reversing valve 13 through the pilot balancing valve. The two groups of switch valves and one pilot balancing valve are used to independently control the action of the actuator; the control system dynamically allocates the output ratio of the large-displacement pump 7 and the small-displacement pump 5 according to the target flow, and adopts the dual-pump joint mode during high-speed movement, and adopts the small-displacement pump independent mode during high-precision docking.

[0053] In some embodiments, the actuator group includes six actuators, namely a first actuator, a second actuator, a third actuator, a fourth actuator, a fifth actuator and a sixth actuator. Figure 1As shown, the execution element group includes swing hydraulic cylinder 14, switch valve one 15, switch valve two 16, pilot balanced valve one 17, pitch hydraulic cylinder 18, switch valve three 19, switch valve four 20, pilot balanced valve two 21, roll hydraulic cylinder 22, switch valve five 23, switch valve six 24, pilot balanced valve three 25, lifting hydraulic cylinder 26, switch valve seven 27, switch valve eight 28, pilot balanced valve four 29, transverse movement hydraulic cylinder 30, switch valve nine 31, switch valve ten 32, pilot balanced valve five 33, switch valve eleven 34, switch valve twelve 35, pilot balanced valve six 36 and hydraulic motor 37; servo motor two 4 is connected with small displacement pump 5, the hydraulic oil inlet of small displacement pump 5 is connected with oil tank through oil return filter one, and the hydraulic oil outlet is connected with the inlet of one-way valve one 8; servo motor one 6 is connected with large displacement pump 7, the hydraulic oil inlet of large displacement pump 7 is connected with oil tank through oil return filter 3, and the hydraulic oil outlet of large displacement pump 7 is connected with the inlet of one-way valve two 9; the P port of three-position four-way reversing valve 13 is connected with the outlet of one-way valve one 8, the outlet of one-way valve two 9 and the inlet of overflow valve 10, the T port is connected with the outlet of overflow valve 10 and oil return filter three 12, the A port is connected with the D port of pilot balanced valve one 17, the D port of pilot balanced valve two 21, the D port of pilot balanced valve three 25, the D port of pilot balanced valve four 29, the D port of pilot balanced valve five 33 and the D port of pilot balanced valve six 36, and the B port is connected with the C port of pilot balanced valve one 17, the C port of pilot balanced valve two 21, the C port of pilot balanced valve three 25, the C port of pilot balanced valve four 29, the C port of pilot balanced valve five 33 and the C port of pilot balanced valve six 36; the A port of switch valve one 15 is connected with the B port of pilot balanced valve one, and the B port is connected with the B port of swing hydraulic cylinder 14; the A port of switch valve two 16 is connected with the A port of pilot balanced valve one, and the B port is connected with the A port of swing hydraulic cylinder; the A port of switch valve three 19 is connected with the B port of pilot balanced valve two 21, and the B port is connected with the B port of pitch hydraulic cylinder 18; the A port of switch valve four 20 is connected with the A port of pilot balanced valve two 21, and the B port is connected with the A port of pitch hydraulic cylinder; the A port of switch valve five 23 is connected with the A port of pilot balanced valve three 25, and the B port is connected with the B port of roll hydraulic cylinder 22; the A port of switch valve six 24 is connected with the A port of pilot balanced valve three 25, and the B port is connected with the A port of roll hydraulic cylinder 22; the A port of switch valve seven 27 is connected with the B port of pilot balanced valve four 29, and the B port is connected with the B port of lifting hydraulic cylinder 26; the A port of switch valve eight 28 is connected with the A port of pilot balanced valve four 29, and the B port is connected with the A port of lifting hydraulic cylinder 26; the A port of switch valve nine 31 is connected with the B port of pilot balanced valve five 33, and the B port is connected with the B port of transverse movement hydraulic cylinder 30; the A port of switch valve ten 32 is connected with the A port of pilot balanced valve five 33, and the B port is connected with the A port of transverse movement hydraulic cylinder 30; the A port of switch valve eleven 34 is connected with the B port of pilot balanced valve six 36, and the B port is connected with hydraulic motor 37; the A port of switch valve twelve 35 is connected with the A port of pilot balanced valve six 36, and the B port is connected with hydraulic motor 37.

[0054] During high-speed segment transport, a dual-pump combination mode is employed, with the control system controlling the lift cylinder 26, traverse cylinder 30, and hydraulic motor 37. When controlling the lift cylinder 26, on-off valve 7 27 and on-off valve 8 28 are in the right position, while the two on-off valves of all other actuators are in the left position. When the lift cylinder is extended, the dual-pump station is set to dual-pump combination mode, with the three-position, four-way directional valve 13 in the right position. Hydraulic oil flows in through port P of the three-position, four-way directional valve 13 and out through port B, then enters port B of the lift cylinder 26 through on-off valve 7. When the lift cylinder is retracted, the dual-pump station is set to dual-pump combination mode, with the three-position, four-way directional valve 13 in the left position. Hydraulic oil flows in through port P of the three-position, four-way directional valve 13 and out through port A, then enters port A of the lift cylinder through on-off valve 8. The two on-off valves corresponding to the lift cylinder 26, traverse cylinder 30, and hydraulic motor 37 are sequentially controlled to achieve the lifting and traverse motion of the segment, thus enabling high-speed segment transport.

[0055] During high-precision segment docking, a small-displacement pump independent mode is employed, with the control system controlling the swing hydraulic cylinder 14, pitch hydraulic cylinder 18, and roll hydraulic cylinder 22. When controlling the swing hydraulic cylinder 14, on-off valve 15 and on-off valve 2 16 are in the right position, while the two on-off valves of all other actuators are in the left position. When the swing hydraulic cylinder 14 is extended, the dual pump station is set to a low-flow, small-pump independent operating mode. The three-position, four-way directional valve 13 is in the right position. Hydraulic oil flows in through port P of the three-position, four-way directional valve 13 and out through port B, then enters port B of the swing hydraulic cylinder 14 through on-off valve 1. When the swing hydraulic cylinder is retracted, the dual pump station is set to a small-displacement, small-pump independent operating mode. The three-position, four-way directional valve 13 is in the left position. Hydraulic oil flows in through port P of the three-position, four-way directional valve 13 and out through port A, then enters port A of the swing hydraulic cylinder through on-off valve 2. The two corresponding switch valves below the swing hydraulic cylinder 14, the pitch hydraulic cylinder 18 and the roll hydraulic cylinder 22 are controlled in sequence to realize the swing, pitch and roll movements of the pipe segment, thereby achieving high-precision docking of the pipe segments.

[0056] Through the above operation, the wide-displacement pump control system proposed in the embodiment of the application has only one execution element working during operation, which ensures that the pressure and flow disturbances caused by different execution elements during the pipe segment moving and splicing are greatly improved, and the control accuracy and stability of the pipe segment splicing are greatly improved. The working process is: first, high-speed pipe segment moving is performed, that is, the lifting hydraulic cylinder 26, the horizontal moving hydraulic cylinder 30 and the hydraulic motor 37 are controlled. When the lifting hydraulic cylinder 26 is controlled, the two switch valves corresponding to the lower part are in the right position, and the two switch valves of all other execution elements are in the left position. The lifting, horizontal moving and rotating actions are completed in sequence, and the movement process needs to ensure that the speed is fast and the accuracy is high, that is, the double-pump combined working mode with large flow. Secondly, high-precision docking is performed, that is, the swing hydraulic cylinder 14, the pitch hydraulic cylinder 18 and the roll hydraulic cylinder 22 are controlled. Similarly, when the swing hydraulic cylinder 14 is controlled, the two switch valves corresponding to the lower part are in the right position, and the two switch valves of all other execution elements are in the left position. The swing, pitch and roll actions are completed in sequence, and the movement process needs to ensure that the speed is fast and the accuracy is high, that is, the small-pump independent working mode with small flow. Through the above operation, the wide-displacement pump control system has only one execution element moving each time, which ensures that the pressure and flow disturbances caused by the simultaneous movement of different execution elements during the pipe segment moving and docking are greatly improved, and the control accuracy and stability are greatly improved.

[0057] In some embodiments, for the control system for controlling the flow of the double-pump station, please refer to Figure 2As shown, first, the double-pump tracking performance test under different hydraulic cylinder desired speeds is carried out to determine the flow range in which the small-displacement pump 5 can maintain the control accuracy. As an example of the present application, the small-displacement pump 5 and the large-displacement pump 7 are gear pumps with a displacement of 3.9 ml / rev and a displacement of 7.8 ml / rev, respectively. The piston diameter, the piston rod diameter and the stroke of the hydraulic cylinder are 90 / 63 / 130 mm. Through the test, when the hydraulic cylinder desired speed is 1-7 mm / s, the maximum hydraulic cylinder desired speed in which the small-displacement pump 5 can ensure the control accuracy is 7 mm / s. When the hydraulic cylinder desired speed reaches 8 mm / s, the small-displacement pump 5 control diverges and the large-displacement pump 7 oscillates obviously. At this time, the double-pump combined control mode should be entered, the small-displacement pump 5 is used to correct and optimize the flow output of the large-displacement pump 7, and the response speed and control accuracy of the pump control system in the high flow range are improved. When the double-pump combined control in the high flow range is used, considering that the small-displacement pump 5 has fast response speed and high control accuracy, the flow output of the small-displacement pump 5 is given priority, and the slow starting speed of the large-displacement pump 7 is compensated. After a set switching time t1, the flow output of the large-displacement pump 7 is given priority, the large flow required by the system is maintained, and the small-displacement pump 5 is only used to correct the flow error, so that the demand of the pump control system for high-speed pipe piece moving and high-precision pipe piece butt joint is met. The flow output ratio a1:b1 of the small-displacement pump 5 and the large-displacement pump 7 before reaching the switching time t1 and the flow output ratio a2:b2 of the small-displacement pump 5 and the large-displacement pump 7 after reaching the switching time t1 need to be determined through the test.

[0058] As an example of the present application, under the double-pump combined control strategy, the optimal switching time t1 is determined to be 2 seconds, the optimal flow output ratio of the small-displacement pump 5 and the large-displacement pump 7 before reaching the switching time is a1:b1=9:1, and the optimal flow output ratio of the small-displacement pump 5 and the large-displacement pump 7 after reaching the switching time is a2:b2=4:6.

[0059] The control system includes a mode controller, which determines the double-pump working mode by judging the target flow q1. If it is in the low flow range, it is controlled and output by the small-displacement pump alone; if it is in the high flow range, the optimal switching time and flow output ratio are found through the test, and then the double-pump is controlled through the PID control module. PID is only an example of the present application, and algorithms such as adaptive control and robust control are also applicable.

[0060] In some embodiments, the control system comprises an expert recommendation system, wherein a database is configured in the expert recommendation system; the database stores a mapping relationship between input parameters and output parameters, wherein the input parameters are: segment size, small pump displacement, large pump displacement, lifting hydraulic cylinder size, transverse movement hydraulic cylinder size, swing hydraulic cylinder size, pitch hydraulic cylinder size, and roll hydraulic cylinder size, and hydraulic motor size. The output parameters include: switching time t1, switching flow rate q1, small pump and large pump flow rate output ratio a1:b1, and small pump and large pump flow rate output ratio a2:b2. In the parameter adjustment process of each different segment assembly hydraulic system, the maximum and average values of the displacement tracking error of the execution element are used as the preferred standard to determine the above output parameters, which are synchronized with the input parameters and uploaded to the control parameter database. With the growth of the database dimension, a mapping relationship between the input and output is established using a machine learning algorithm, such as the nearest neighbor algorithm, back propagation neural network, etc., to form an expert recommendation system. In a new tunnel segment assembly control system, given specific input parameters, the expert recommendation system will give the optimal control parameters.

[0061] In summary, the wide-displacement pump control system that takes into account high-speed segment movement and high-precision segment docking can meet the requirements of stability, response speed, and high precision. The wide-displacement pump control system mainly realizes flow output through dynamic error distribution of large-displacement pumps and small-displacement pumps. The introduction of this set of wide-flow pump control hydraulic system brings the following advantages: first, it effectively improves the system response speed, even in a large flow range, by increasing the output proportion of small-displacement pumps at the initial stage of system operation, thereby avoiding the slow response speed of large-displacement pumps; second, considering that the controllable minimum displacement of large-displacement pumps is too large to meet the high-precision requirements of the system in medium and large flow ranges, the small-displacement pumps are used to correct the system control precision, achieving high-precision output of the wide-flow range pump control system to meet the high precision of the segment assembly machine during high-speed movement; third, the output proportion of the double pumps can be dynamically adjusted in different flow ranges, rather than using a simple control mode of small-flow pumps for small-flow output and large-flow pumps for large-flow output. A double-pump dynamic adjustment control method is proposed to achieve wide-displacement high-precision pump control.

[0062] Embodiment 2:

[0063] The embodiment of the present application provides a control method for the wide-displacement pump control system that takes into account high-speed segment movement and high-precision segment docking, as described in any of the embodiments of embodiment 1, and the control method comprises the following steps:

[0064] S1: Determine the working mode according to the target flow rate: if the target flow rate is a high flow rate requirement, enter the double-pump joint control mode; if it is a low flow rate requirement, enter the small-displacement pump independent mode;

[0065] S2: In the dual-pump combination mode, control the small and large displacement pumps to output flow according to the preset ratio, and adjust the ratio after the preset switching time;

[0066] S3: Select the current actuator through the switch valve group to ensure that only one actuator works at a time;

[0067] S4: Real-time acquisition of actuator displacement data, correction of dual-pump output ratio through closed-loop control algorithm, and ensuring that the displacement tracking error is less than the set threshold.

[0068] In some embodiments, the closed-loop control algorithm is PID control, adaptive control or robust control.

[0069] In some embodiments, the maximum value of the displacement tracking error is not more than ±0.5mm.

[0070] In some embodiments, the expert recommendation system recommends the switching time (t1), flow threshold (q1) and dual-pump flow ratio in real time according to the input parameters, realizing unmanned automatic control.

[0071] The above embodiments are only used to illustrate the present application, and are not intended to limit the present application. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present application. Therefore, all equivalent technical solutions also belong to the scope of the present application, and the patent protection scope of the present application shall be defined by the claims.

Claims

1. A wide-displacement pump control system that balances high-speed pipe piece transfer and high-precision pipe piece butt joint, characterized in that, The utility model relates to a kind of hydraulic control systems for segmental bridge girder, comprising: Oil tank for storing hydraulic oil; Large displacement pump and small displacement pump arranged in parallel, respectively driven by servo motor one and servo motor two, the import of the large displacement pump and the small displacement pump is connected by oil return filter one and oil return filter two pipeline the oil tank, the outlet of the large displacement pump and the small displacement pump is connected by one-way valve one and one-way valve two into main oil supply pipeline; Three-position four-way directional control valve, P mouth connects main oil supply pipeline, T mouth connects oil return filter three, A mouth and B mouth are connected with the communication of actuator group; Actuator group, including multiple actuators, each actuator includes hydraulic cylinder, switch valve and pilot operated balancing valve, the actuator is connected with the A mouth and B mouth of the three-position four-way directional control valve by the pilot operated balancing valve, two groups of switch valve and a pilot operated balancing valve are used to independently control the actuator action; Control system, for dynamically allocating the output proportion of the large displacement pump and the small displacement pump according to target flow, and using double-pump combined mode when segmental bridge girder is moved, using small displacement pump independent mode when segmental bridge girder is jointed.

2. The wide capacity pump control system for high speed pipe section transfer and high precision pipe section butt joining according to claim 1, characterized in that, The actuator group includes six actuators, which are first actuator, second actuator, third actuator, fourth actuator, fifth actuator and sixth actuator; The first actuator includes swing hydraulic cylinder, switch valve one, switch valve two and pilot operated balancing valve one; The second actuator includes pitch hydraulic cylinder, switch valve three, switch valve four and pilot operated balancing valve two; The third actuator includes roll hydraulic cylinder, switch valve five, switch valve six and pilot operated balancing valve three; The fourth actuator includes lifting hydraulic cylinder, switch valve seven, switch valve eight and pilot operated balancing valve four; The fifth actuator includes transverse movement hydraulic cylinder, switch valve nine, switch valve ten and pilot operated balancing valve five; The sixth actuator includes switch valve eleven, switch valve twelve, pilot operated balancing valve six and hydraulic motor.

3. The wide capacity pump control system for high speed pipe section transfer and high precision pipe section butt joining according to claim 2, characterized in that, The A mouth of the three-position four-way directional control valve is connected with the D mouth of the pilot operated balancing valve one, the D mouth of the pilot operated balancing valve two, the D mouth of the pilot operated balancing valve three, the D mouth of the pilot operated balancing valve four, the D mouth of the pilot operated balancing valve five and the D mouth of the pilot operated balancing valve six, and the B mouth of the three-position four-way directional control valve is connected with the C mouth of the pilot operated balancing valve one, the C mouth of the pilot operated balancing valve two, the C mouth of the pilot operated balancing valve three, the C mouth of the pilot operated balancing valve four, the C mouth of the pilot operated balancing valve five and the C mouth of the pilot operated balancing valve six; The A mouth of the switch valve one is connected with the B mouth of the pilot operated balancing valve one, and the B mouth is connected with the B mouth of the swing hydraulic cylinder;The A mouth of the switch valve two is connected with the A mouth of the pilot operated balancing valve one, and the B mouth is connected with the A mouth of the swing hydraulic cylinder; The A mouth of the switch valve three is connected with the B mouth of the pilot operated balancing valve two, and the B mouth is connected with the B mouth of the pitch hydraulic cylinder;The A mouth of the switch valve four is connected with the A mouth of the pilot operated balancing valve two, and the B mouth is connected with the A mouth of the pitch hydraulic cylinder; The A mouth of the switch valve five is connected with the A mouth of the pilot operated balancing valve three, and the B mouth is connected with the B mouth of the roll hydraulic cylinder;The A mouth of the switch valve six is connected with the A mouth of the pilot operated balancing valve three, and the B mouth is connected with the A mouth of the roll hydraulic cylinder; The A mouth of the switch valve seven is connected with the A mouth of the pilot operated balancing valve four, and the B mouth is connected with the B mouth of the lifting hydraulic cylinder;The A mouth of the switch valve eight is connected with the A mouth of the pilot operated balancing valve four, and the B mouth is connected with the A mouth of the lifting hydraulic cylinder; The A mouth of the switch valve nine is connected with the A mouth of the pilot operated balancing valve five, and the B mouth is connected with the B mouth of the transverse movement hydraulic cylinder;The A mouth of the switch valve ten is connected with the A mouth of the pilot operated balancing valve five, and the B mouth is connected with the A mouth of the transverse movement hydraulic cylinder; The A mouth of the switch valve eleven is connected with the A mouth of the pilot operated balancing valve six, and the B mouth is connected with the B mouth of the hydraulic motor;The A mouth of the switch valve twelve is connected with the A mouth of the pilot operated balancing valve six, and the B mouth is connected with the A mouth of the hydraulic motor. The A port of the switch valve seven is connected with the B port of the pilot balanced valve four, and the B port is connected with the B port of the lifting hydraulic cylinder; the A port of the switch valve eight is connected with the A port of the pilot balanced valve four, and the B port is connected with the A port of the lifting hydraulic cylinder; The A port of the switch valve nine is connected with the B port of the pilot balanced valve five, and the B port is connected with the B port of the horizontal moving hydraulic cylinder; the A port of the switch valve ten is connected with the A port of the pilot balanced valve five, and the B port is connected with the A port of the horizontal moving hydraulic cylinder; The A port of the switch valve eleven is connected with the B port of the pilot balanced valve six, and the B port is connected with the hydraulic motor; the A port of the switch valve twelve is connected with the A port of the pilot balanced valve six, and the B port is connected with the hydraulic motor.

4. The wide capacity pump control system for high speed pipe section transfer and high precision pipe section butt joining according to claim 2 or 3, characterized in that, In the double-pump combined mode, the control system controls the lifting hydraulic cylinder, the horizontal moving hydraulic cylinder and the hydraulic motor; when the lifting hydraulic cylinder is controlled, the switch valve seven and the switch valve eight are in the right position, and all the other two switch valves of the execution elements are in the left position; when the lifting hydraulic cylinder is pushed out, the three-position four-way reversing valve is in the right position, the hydraulic oil flows in through the P port of the three-position four-way reversing valve and flows out through the B port, and then enters the B port of the lifting hydraulic cylinder through the switch valve seven; when the lifting hydraulic cylinder is retracted, the three-position four-way reversing valve is in the left position, the hydraulic oil flows in through the P port of the three-position four-way reversing valve and flows out through the A port, and then enters the A port of the lifting hydraulic cylinder through the switch valve eight; the corresponding two switch valves of the lifting hydraulic cylinder, the horizontal moving hydraulic cylinder and the hydraulic motor are controlled in sequence to realize the lifting and horizontal moving actions of the pipe piece, so that the pipe piece is moved and transported at high speed.

5. The wide capacity pump control system for high speed pipe section transfer and high precision pipe section butt joining according to claim 2 or 3, characterized in that, In the small-displacement pump independent mode, the control system controls the swing hydraulic cylinder, the pitching hydraulic cylinder and the rolling hydraulic cylinder; when the swing hydraulic cylinder is controlled, the switch valve one and the switch valve two are in the right position, and all the other two switch valves of the execution elements are in the left position; when the swing hydraulic cylinder is pushed out, the three-position four-way reversing valve is in the right position, the hydraulic oil flows in through the P port of the three-position four-way reversing valve and flows out through the B port, and then enters the B port of the swing hydraulic cylinder through the switch valve one; when the swing hydraulic cylinder is retracted, the three-position four-way reversing valve is in the left position, the hydraulic oil flows in through the P port of the three-position four-way reversing valve and flows out through the A port, and then flows into the A port of the swing hydraulic cylinder through the switch valve two; the corresponding two switch valves below the swing hydraulic cylinder, the pitching hydraulic cylinder and the rolling hydraulic cylinder are controlled in sequence to realize the swing, pitching and rolling actions of the pipe piece, so that the pipe piece is butt-jointed with high precision.

6. The wide capacity pump control system for high speed pipe section moving and high precision pipe section joining according to claim 1, characterized in that, The control system comprises a mode controller, which determines the double-pump working mode based on the target flow rate: When the target flow rate is less than a set threshold, only the small-displacement pump is enabled to output the flow rate with high precision; When the target flow rate is greater than or equal to the set threshold, the double-pump combined mode is enabled, and the small-displacement pump is preferentially used for outputting within a preset switching time, and then the large-displacement pump is used for outputting.

7. The wide capacity pump and control system for high speed tube sheet transfer and high precision tube sheet joining of claim 6, wherein, In the double-pump combined mode, the flow rate output ratio of the small-displacement pump to the large-displacement pump is 9:1 before the preset switching time and is adjusted to 4:6 after the preset switching time.

8. The wide capacity pump and control system for high speed tube sheet transfer and high precision tube sheet joining of claim 1, wherein, The control system comprises an expert recommendation system, a database is configured in the expert recommendation system, the database stores a mapping relationship between input parameters and output parameters, the mapping relationship between the input parameters and the output parameters is established through a machine learning algorithm, the machine learning algorithm is a back propagation neural network or a nearest neighbor algorithm, the input parameters are pipe specifications, small pump displacement, large pump displacement, lifting hydraulic cylinder specifications, transverse movement hydraulic cylinder specifications, swing hydraulic cylinder specifications, pitch hydraulic cylinder specifications, roll hydraulic cylinder specifications and hydraulic motor specifications, and the output parameters include preset switching time, switching flow, small pump and large pump flow output ratio and small pump and large pump flow output ratio.

9. A control method of a wide capacity pump control system for high speed pipe segment transfer and high precision pipe segment butt joining according to any one of claims 1 to 8, characterized in that, The control method comprises: determining the working mode according to the target flow: if the target flow is a high flow demand, entering a double-pump combined control mode; if it is a low flow demand, entering a small-displacement pump independent mode; in the double-pump combined mode, controlling the small-displacement pump and the large-displacement pump to output flow according to a preset ratio, and adjusting the ratio after a preset switching time; selecting the execution element of the current action through the switch valve group, ensuring that only one execution element works at a time; real-time acquisition of execution element displacement data, correction of the double-pump output ratio through a closed-loop control algorithm, and ensuring that the displacement tracking error is less than a set threshold.

10. The control method according to claim 9, characterized by, The closed-loop control algorithm is a PID control, an adaptive control or a robust control.

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