Hydraulic cylinder variable pump control system based on load force feedback

Abstract

The invention relates to a hydraulic cylinder variable pump control system based on load force feedback. The hydraulic cylinder variable pump control system comprises a hydraulic cylinder part, a hydraulic oil way part and a signal feedback control part. The system mainly comprises a hydraulic cylinder, a variable pump, a force sensor, a PID (Proportion Integration Differentiation) controller and a three-position four-way electromagnetic valve. The hydraulic cylinder converts hydraulic energy into mechanical energy, and linear motion or force output is achieved. The variable pump adjusts output flow and pressure according to system requirements. The force sensor monitors the load force borne by the hydraulic cylinder in real time and converts a force signal into an electric signal. The PID controller receives a signal of the force sensor and dynamically adjusts the output displacement of the variable pump so as to be matched with the change of the load force. The three-position four-way solenoid valve controls the flow direction and flow of hydraulic oil according to an instruction of the PID controller, and accurate control over movement of the hydraulic cylinder is achieved. Through the closed-loop control mode, the system can quickly respond to load changes, control precision is improved, meanwhile, energy consumption is reduced, and the working efficiency and stability of the hydraulic cylinder are improved.

Description

Technical Field

[0001] The invention relates to the technical field of hydraulic systems, and in particular to a hydraulic cylinder variable pump control system based on load force feedback. Background Art

[0002] In traditional hydraulic systems, the control of variable pump output pressure usually relies on fixed parameter settings or simple pressure sensor feedback. Although this control method can meet general application needs, under complex working conditions, especially in scenarios where loads change frequently or load force accuracy is required, traditional methods often have difficulty in achieving precise regulation of pressure and flow, leading to problems such as low system efficiency, increased energy consumption, and slow response. In addition, due to the lack of direct feedback on load force changes, it is difficult for the system to ensure the stability and control accuracy of the hydraulic cylinder when facing nonlinear loads or dynamic working conditions. Summary of the invention

[0003] The present invention provides a hydraulic cylinder variable pump control system based on load force feedback. The load force of the hydraulic cylinder is monitored in real time, and the output displacement of the variable pump is adjusted according to the load force. The output of the variable pump is adjusted according to the change of the external load to ensure that the pressure in the hydraulic cylinder is equal to the external load force. This method can reduce system oscillation and impact, thereby improving the efficiency and stability of the system.

[0004] The system mainly includes hydraulic cylinder, variable pump, force sensor, PID controller and three-position four-way solenoid valve. As an actuator, the hydraulic cylinder converts hydraulic energy into mechanical energy to achieve linear motion or force output. The variable pump adjusts the output flow and pressure according to system requirements to adapt to different working conditions. The force sensor monitors the load force on the hydraulic cylinder in real time and converts the force signal into an electrical signal. The PID controller receives the signal from the force sensor and dynamically adjusts the output displacement of the variable pump to match the change in load force through proportional, integral and differential control algorithms. The three-position four-way solenoid valve controls the flow direction and flow of the hydraulic oil according to the instructions of the PID controller to achieve precise control of the movement of the hydraulic cylinder. Through this closed-loop control method, the system can quickly respond to load changes, improve control accuracy, reduce energy consumption, and improve the working efficiency and stability of the hydraulic cylinder.

[0005] The present invention discloses a hydraulic cylinder variable pump control system based on load force feedback, comprising a hydraulic oil circuit part, a hydraulic cylinder part, and a signal feedback control part; the hydraulic oil circuit part comprises an oil tank, a motor, a variable pump, a three-position four-way solenoid valve, and a flow pressure detection device; the hydraulic cylinder part comprises a hydraulic cylinder, a load, a displacement sensor, and a force sensor; the signal feedback control part comprises an actual power converter, a theoretical power converter, a first signal comparison point, a power displacement converter, a second signal comparison point, a PID controller, a first signal gain device, and a second signal gain device.

[0006] The motor is electrically connected to the variable pump, the input end of the variable pump is connected to the oil tank, the output end is connected to the P port of the three-position four-way solenoid valve, the A port of the three-position four-way solenoid valve is connected to the rodless cavity of the hydraulic cylinder, the B port is connected to the rod cavity of the hydraulic cylinder, and the T port is connected to the oil tank.

[0007] When the valve core of the three-position four-way solenoid valve is in the left position, the variable pump is connected to the rodless chamber of the hydraulic cylinder, and the oil tank is connected to the rod chamber of the hydraulic cylinder; when the valve core of the three-position four-way solenoid valve is in the right position, the variable pump is connected to the rod chamber of the hydraulic cylinder, and the oil tank is connected to the rodless chamber of the hydraulic cylinder.

[0008] When the rodless chamber of the hydraulic cylinder is supplied with high-pressure oil, the valve core of the three-position four-way solenoid valve is located in the left position, the motor drives the variable pump to suck oil and send the oil into the rodless chamber of the hydraulic cylinder, and the excess oil in the rod chamber flows back to the oil tank through the T port; when the rod chamber of the hydraulic cylinder is supplied with high-pressure oil, the valve core of the three-position four-way solenoid valve is located in the right position, the motor drives the variable pump to suck oil and send the oil into the rod chamber of the hydraulic cylinder, and the excess oil in the rodless chamber flows back to the oil tank through the T port.

[0009] A flow pressure detection device is connected to the pipeline between the variable pump and the three-position four-way solenoid valve. The flow pressure detection device is used to input the pressure signal detected before the inlet of the three-position four-way solenoid valve into the actual power converter in the signal feedback control part.

[0010] Hydraulic cylinders are used to move loads.

[0011] The displacement sensor is used to collect the displacement signal of the hydraulic cylinder piston rod movement and transmit the displacement signal to the actual power converter. The actual power converter is used to calculate the displacement signal of the hydraulic cylinder piston rod movement and the pressure signal before the inlet of the three-position four-way solenoid valve, and transmit the actual power signal obtained after the calculation to the first signal comparison point; the force sensor is used to detect the load force change signal and transmit the signal to the theoretical power converter. The theoretical power converter calculates the load force change signal and also transmits the theoretical power signal obtained after the calculation to the first signal comparison point; the first signal comparison point performs a difference operation on the power signals respectively transmitted by the actual power converter and the theoretical power converter to obtain a power correction signal, and transmits the power correction signal to the power displacement converter. The power displacement converter converts the input power correction signal into a displacement correction signal and transmits it to the second signal comparison point. The second signal comparison point adds the displacement correction signal input by the power displacement converter and the manually input default displacement instruction and transmits the calculation result to the PID controller. The output signal of the PID controller is respectively transmitted to the variable pump through the first signal gain device and to the control end of the three-position four-way solenoid valve through the second signal gain device;

[0012] Furthermore, the hydraulic oil circuit part also includes an overflow valve, which is connected to the pipeline between the variable pump and the three-position four-way solenoid valve. The connection point between the overflow valve and the above pipeline is located before the connection point between the flow pressure detection device and the above pipeline. The oil passing through the overflow valve eventually flows back to the oil tank. The overflow valve is used to automatically adjust the system pressure to prevent overload and protect the safe operation of the equipment.

[0013] Furthermore, the hydraulic oil circuit part also includes a variable throttle, which is arranged on the pipeline connecting the B port of the three-position four-way solenoid valve and the rod chamber of the hydraulic cylinder. The opening size of the variable throttle is adjusted by manual instructions to adjust the oil flow rate, thereby controlling the movement speed of the hydraulic cylinder piston rod.

[0014] Furthermore, the signal feedback control part also includes a two-way switch, which is arranged between the PID controller and the second signal gain device. The two-way switch selects the input signal according to the manual instruction K value. When the manual instruction K value is 0, the two-way switch is correspondingly placed at position 0, at which time the PID controller is disconnected from the three-position four-way solenoid valve, and it is manual control at this time, and the valve core of the three-position four-way solenoid valve is in the middle position; when the manual instruction K value is -1, the two-way switch is correspondingly placed at position -1, at which time the PID controller is disconnected from the three-position four-way solenoid valve, and it is manual control at this time, and the valve core of the three-position four-way solenoid valve is in the right position; when When the manual instruction K value is 1, the two-way switch is set to position 1. At this time, the PID controller is disconnected from the three-position four-way solenoid valve. At this time, it is manual control. The valve core of the three-position four-way solenoid valve is in the left position, that is, the two-way switch can manually control the valve core position of the three-position four-way solenoid valve; when the manual instruction K value is other than 0, -1, and 1, such as 2, the two-way switch is connected to the output end of the PID controller. At this time, the system is automatically controlled, and the output signal of the PID controller controls the displacement of the variable pump through the first signal gain device and the position of the valve core of the three-position four-way solenoid valve through the second signal gain device.

[0015] Furthermore, the actual power converter operates the displacement signal of the hydraulic cylinder piston rod and the pressure signal detected before the inlet of the three-position four-way solenoid valve, and its internal algorithm formula is:

[0016]

[0017] Where, K: leakage coefficient; A: effective working area of ​​the piston; t: time; x: collected displacement signal of the hydraulic cylinder piston rod; y: pressure signal detected before the inlet of the three-position four-way solenoid valve, f (x,y) is the actual power.

[0018] The hydraulic cylinder control system that controls the output displacement of the variable pump by load force feedback can effectively overcome the shortcomings of traditional hydraulic system control. Its core lies in real-time perception of the change of load force and using it as the basis for adjusting the displacement of the variable pump. This method can dynamically adjust the output displacement according to the load demand, avoiding the energy waste caused by setting the displacement too high, and significantly improving the response speed and control accuracy of the hydraulic system. Especially in the fields of high-precision industrial equipment, engineering machinery and aerospace, the dynamic adjustment of displacement achieved by load force feedback technology can greatly improve the stability and operation efficiency of the system, and provide reliable guarantee for key tasks. In addition, this control method based on load force feedback is also highly adaptable and can achieve precise control of the movement of the hydraulic cylinder under a variety of complex working conditions. With the growing demand for efficient and intelligent hydraulic systems in the industrial field, the application prospects of this technology are becoming more and more broad. It can not only improve the overall performance of the hydraulic system, but also reduce the energy consumption and wear of the equipment and extend the life of the system, which is of great significance under the trend of green energy saving and intelligent manufacturing.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The present invention uses AMESim software to model the output displacement of a variable pump controlled by load force feedback, so that a force sensor can obtain real-time load force data, and the load force data is input into a controller, and the controller uses a PID control algorithm to calculate a corresponding variable pump displacement setting value; the controller can adjust the output displacement of the variable pump according to the calculation result so that it is proportional to the load force; the external load force feedback mechanism can accurately control the hydraulic cylinder, and the output displacement can be dynamically adjusted according to the load demand, which significantly improves the response speed and control accuracy of the system, reduces the energy waste caused by the excessively high displacement setting of the traditional system, thereby effectively reducing energy consumption and improving system efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a system principle diagram of a hydraulic cylinder variable pump control system based on load force feedback of the present invention;

[0022] Figure 2 It is an AMESim simulation model corresponding to the system principle diagram of a hydraulic cylinder variable pump control system based on load force feedback of the present invention.

[0023] Reference numerals

[0024] 1- oil tank, 2- motor, 3- variable pump, 4- three-position four-way solenoid valve, 5- variable throttle port, 6- overflow valve, 7- flow pressure detection device, 8- hydraulic cylinder, 9- load, 10- displacement sensor, 10'- displacement signal acquisition element, 11- force sensor, 11'- load force detection element, 12- actual power converter, 12'- actual signal input operation module, 13- theoretical power converter, 13'- theoretical signal input operation module, 14- first signal ratio Comparison point, 15-power displacement converter, 15'-power displacement conversion module, 16-second signal comparison point, 17-PID controller, 18-first signal gain device, 18'-first signal gain module, 19-second signal gain device, 19'-second signal gain module, 20-bidirectional switch, 20'-bidirectional signal exchange module, 81-mass block element, 82-hydraulic cylinder body element, 91-signal input element, 92-pressure conversion element, 21-zero force source. DETAILED DESCRIPTION

[0025] In order to better understand the content of the present invention, the present invention will be further described below in conjunction with specific embodiments and drawings. The following embodiments are implemented based on the technology of the present invention, and detailed implementation methods and operating steps are given, but the protection scope of the present invention is not limited to the following embodiments.

[0026] See also Figure 1 A hydraulic cylinder variable pump control system based on load force feedback includes a hydraulic oil circuit part, a hydraulic cylinder part, and a signal feedback control part; the hydraulic oil circuit part includes an oil tank 1, a motor 2, a variable pump 3, a three-position four-way solenoid valve 4, a variable throttle 5, a relief valve 6, and a flow pressure detection device 7; the hydraulic cylinder part includes a hydraulic cylinder 8, a load 9, a displacement sensor 10, and a force sensor 11; the signal feedback control part includes an actual power converter 12, a theoretical power converter 13, a first signal comparison point 14, a power displacement converter 15, a second signal comparison point 16, a PID controller 17, a first signal gain device 18, a second signal gain device 19, and a bidirectional switch 20.

[0027] Motor 2 provides power source for the system. Motor 2 drives variable pump 3 to draw oil from oil tank 1 and supply it to the inside of the oil circuit. Port A of three-position four-way solenoid valve 4 is connected to the rodless chamber of hydraulic cylinder 8, port B is connected to the rod chamber of hydraulic cylinder, port P is connected to the output end of variable pump 3, and port T is connected to oil tank 1. When the valve core of three-position four-way solenoid valve is in the left position, variable pump 3 is connected to the rodless chamber of hydraulic cylinder, and oil tank 1 is connected to the rod chamber of hydraulic cylinder; when the valve core of three-position four-way solenoid valve is in the right position, variable pump 3 is connected to the rod chamber of hydraulic cylinder, and oil tank 1 is connected to the rodless chamber of hydraulic cylinder.

[0028] When the rodless chamber of the hydraulic cylinder is supplied with high-pressure oil, the valve core of the three-position four-way solenoid valve is located in the left position, the motor drives the variable pump to suck oil and send the oil into the rodless chamber of the hydraulic cylinder, and the excess oil in the rod chamber flows back to the oil tank through the T port; when the rod chamber of the hydraulic cylinder is supplied with high-pressure oil, the valve core of the three-position four-way solenoid valve is located in the right position, the motor drives the variable pump to suck oil and send the oil into the rod chamber of the hydraulic cylinder, and the excess oil in the rodless chamber flows back to the oil tank through the T port.

[0029] The variable throttle port 5 is arranged on the pipeline connecting the B port of the three-position four-way solenoid valve and the hydraulic cylinder. The opening size of the variable throttle port is adjusted by manual command to adjust the oil flow speed, thereby controlling the movement speed of the hydraulic cylinder piston rod.

[0030] The pipeline between the variable pump and the three-position four-way solenoid valve is connected to the overflow valve 6. The oil passing through the overflow valve eventually flows back to the oil tank. The overflow valve is used to automatically adjust the system pressure to prevent overload and protect the safe operation of the equipment.

[0031] The pipeline between the variable pump and the three-position four-way solenoid valve is also connected to the flow pressure detection device 7, and the connection point between the flow pressure detection device and the above pipeline is located after the connection point between the overflow valve and the above pipeline. The flow pressure detection device inputs the pressure signal detected before the inlet of the three-position four-way solenoid valve into the actual power converter 12 in the signal feedback control part.

[0032] The displacement sensor 10 collects the displacement signal of the hydraulic cylinder piston movement and transmits the displacement signal to the actual power converter 12. The actual power converter calculates the displacement signal of the hydraulic cylinder piston movement and the pressure signal before the inlet of the three-position four-way solenoid valve, and transmits the actual power signal obtained after the calculation to the first signal comparison point 13; the force sensor 11 is used to detect the load force change signal and transmit the signal to the theoretical power converter 13. The theoretical power converter calculates the load force change signal and transmits the theoretical power signal obtained after the calculation to the first signal comparison point 14. That is, when the system performs work on the load 9, the load is collected. The force signal and the displacement signal of the hydraulic cylinder piston movement are sent to the signal feedback control part; the first signal comparison point 14 performs a difference operation on the power signals respectively transmitted by the actual power converter and the theoretical power converter to obtain a power correction signal, and transmits the power correction signal to the power displacement converter 15. The power displacement converter 15 converts the input power correction signal into a displacement correction signal and transmits it to the second signal comparison point 16. The second signal comparison point 16 adds the displacement correction signal and the manually input default displacement instruction and transmits the operation result to the PID controller 17. The output signals of the PID controller are respectively transmitted through the first signal The signal gain device 18 transmits it to the variable pump, and the second signal gain device 19 transmits it to the control end of the three-position four-way solenoid valve; a two-way switch 20 is set between the PID controller and the second signal gain device, and the two-way switch selects the input signal according to the manual instruction K value. When the manual instruction K value is 0, the two-way switch is correspondingly placed in the 0 position. At this time, the PID controller is disconnected from the three-position four-way solenoid valve. At this time, it is manual control, and the valve core of the three-position four-way solenoid valve is in the middle position; when the manual instruction K value is -1, the two-way switch is correspondingly placed in the -1 position. At this time, the PID controller is disconnected from the three-position four-way solenoid valve. At this time, it is manual control, and the valve core of the three-position four-way solenoid valve is in the middle position. The valve core is in the right position; when the manual instruction K value is 1, the two-way switch is correspondingly placed in position 1, and the PID controller is disconnected from the three-position four-way solenoid valve. At this time, it is manual control, and the valve core of the three-position four-way solenoid valve is in the left position, that is, the two-way switch can manually control the valve core position of the three-position four-way solenoid valve; when the manual instruction K value is other than 0, -1, and 1, such as 2, the two-way switch is connected to the output end of the PID controller. At this time, the system is under automatic control, and the output signal of the PID controller controls the displacement of the variable pump through the first signal gain device and the position of the valve core of the three-position four-way solenoid valve through the second signal gain device.

[0033] The real power converter calculates the displacement signal of the hydraulic cylinder piston rod and the pressure signal detected before the inlet of the three-position four-way solenoid valve. Its internal algorithm formula is:

[0034]

[0035] Where, K: leakage coefficient; A: effective working area of ​​the piston; t: time; x: collected displacement signal of the hydraulic cylinder piston rod; y: pressure signal detected before the inlet of the three-position four-way solenoid valve, f (x,y) is the actual power.

[0036] The signal source of the signal feedback control part is the load force command and the force sensor of the hydraulic cylinder part. The theoretical power converter calculates the load force signal detected by the force sensor. Its internal algorithm formula is:

[0037]

[0038] Where, V: moving speed; A: effective area of ​​hydraulic cylinder piston; x: collected load force signal; f (x) is the theoretical power.

[0039] according to Figure 1 , use AMESim simulation to obtain the AMESim simulation model, please refer to Figure 2 The AMESim simulation model includes a hydraulic oil circuit part, a hydraulic cylinder part, and a signal feedback control part; the hydraulic oil circuit part includes an oil tank 1, a motor 2 in a mechanical library (Mechanical), a variable pump 3 in a hydraulic library (Hydraulic), a three-position four-way solenoid valve 4, a variable throttle 5, a relief valve 6, and a flow pressure detection device 7; the hydraulic cylinder part includes a mass block element 81 for simulating the weight of the hydraulic cylinder itself, a hydraulic cylinder body element 82 for simulating the actual hydraulic cylinder structure, and a signal feedback control device 83 for providing a signal to the load. The input signal input element 91, the pressure conversion element 92 for converting the signal input into the force, the displacement signal acquisition element 10', the load force detection element 11' and the zero force source 21; the signal feedback control part includes the actual signal input operation module 12', the theoretical signal input operation module 13', the first signal comparison point 14, the power displacement conversion module 15', the second signal comparison point 16, the PID controller 17, the first signal gain module 18', the second signal gain module 19', and the two-way signal exchange module 20'. The mass block element 81 and the hydraulic cylinder body element 82 are equivalent to Figure 1 The hydraulic cylinder 8 in the signal input element 91 and the pressure conversion element 92 are equivalent to Figure 1 The load 9 in the displacement signal acquisition element 10' is equivalent to Figure 1 The displacement sensor 10 and the load force detection element 11' are equivalent to Figure 1 The force sensor 11 in the actual signal input operation module 12' is equivalent to Figure 1 The actual power converter 12 in the embodiment, the theoretical signal input operation module 13' is equivalent to Figure 1 The theoretical power converter 13 in the power displacement conversion module 15' is equivalent to Figure 1The power displacement converter 15 in the embodiment of the present invention, the first signal gain module 18' is equivalent to Figure 1 The first signal gain module 18 and the second signal gain module 19' are equivalent to Figure 1 The second signal amplifier 19 in the bidirectional signal exchange module 20' is equivalent to Figure 1 The bidirectional switch 20 in.

[0040] The PID controller 17 makes the output signal more stable; the first signal gain module is used to convert the control signal into a feedback signal, which is input to the feedback control part, i.e., the variable pump; the second signal gain module is used to convert the control signal into a feedback signal, which is input to the feedback control part, i.e., the three-position four-way solenoid valve;

[0041] The two-way signal exchange module 20' selects the input signal according to the manual instruction K value. When the manual instruction K value is 0, the two-way signal exchange module is in the 0 position. At this time, the upper switch of the two-way signal exchange module is closed. At this time, the PID controller is disconnected from the three-position four-way solenoid valve. At this time, it is manual control, and the valve core of the three-position four-way solenoid valve is in the middle position; when the manual instruction K value is -1, the two-way signal exchange module is in the -1 position. At this time, the upper switch of the two-way signal exchange module is closed, that is, the PID controller is disconnected from the two-way signal exchange module. At this time, it is manual control, and the valve core of the three-position four-way solenoid valve is correspondingly located in the right ... is 1, the two-way signal exchange module is in position 1, at this time the upper switch of the two-way signal exchange module is closed, the PID controller is disconnected from the two-way signal exchange module, this is manual control, and the valve core of the three-position four-way solenoid valve is correspondingly in the left position; when the manual instruction K value is other than -1, 0, and 1, the lower switch of the two-way signal exchange module is closed, that is, the two-way signal exchange module is connected to the output end of the PID controller, and the system is automatic control. The output signal of the PID controller controls the displacement of the variable pump through the first signal gain module and the position of the valve core of the three-position four-way solenoid valve through the second signal gain module.

[0042] When the external load of the system changes, the signal collected by the hydraulic cylinder load force detection element enters the signal feedback control part, and the manual instruction K is input (the K value is other values ​​except -1, 0, and 1, such as 10). The two-way signal exchange module is connected to the output end of the PID controller, and the valve core position of the three-position four-way solenoid valve is controlled by the PID controller through the second signal gain module. The control signal will change according to the increase or decrease of the load force; when the external load force increases, the system needs to lift the hydraulic cylinder, so the signal feedback control part controls the three-position four-way solenoid valve to the left position, which is the lifting state at this time; when the external load force decreases, the system needs to relieve the pressure on the hydraulic cylinder, so the signal feedback control part controls the three-position four-way solenoid valve to the right position, which is the pressure relief state at this time.

[0043] The detection signal of the flow pressure detection device of the hydraulic oil circuit part and the detection signal of the hydraulic cylinder piston rod displacement signal acquisition element are passed to the actual signal input operation module of the signal feedback control part, and after being processed by the actual signal input operation module and the first signal comparison point 14, the power displacement conversion module 15', and the second signal comparison point 16, they become one of the signal sources of the PID controller;

[0044] The hydraulic cylinder part is an external load hydraulic cylinder simulation model built in the AMESim module by coordinating the design module in the hydraulic component design library (Hydraulic Component Design) with the quality module in the mechanical library (Mechanical). This model can simulate the movement of the hydraulic cylinder and the state of doing external work; the signal feedback control part is composed of the signal control library (Signal, Control), which is used to collect the size change signal of the external load force, the pressure signal detected in front of the inlet of the three-position four-way solenoid valve and the displacement signal of the hydraulic cylinder piston movement. At the same time, through signal processing and transmission, the control of the variable pump displacement and the control of the valve core position of the three-position four-way solenoid valve are realized.

[0045] The working process of the hydraulic cylinder variable pump control system based on load force feedback in this embodiment is as follows:

[0046] The hydraulic cylinder variable pump control system based on load force feedback mainly uses the signal feedback part to dynamically adjust the core components of the hydraulic system in real time. The hydraulic oil circuit part is powered by the motor to drive the variable pump to output pressure, and combines the signal detected by the flow pressure detection device to achieve precise control of the system pressure. When the three-position four-way solenoid valve changes the flow direction of the oil circuit, the hydraulic cylinder piston rod can be lifted or lowered. At the same time, the oil flow rate is controlled by adjusting the size of the variable throttle opening by inputting manual commands, thereby flexibly adjusting the lifting or pressure relief speed of the hydraulic cylinder piston rod. The signal feedback control part receives the pressure signal from the flow pressure detection device in real time, and combines the real-time feedback signal of the hydraulic cylinder load and displacement for comprehensive calculation and feedback to the variable pump and the three-position four-way solenoid valve, thereby ensuring the system's precise control of the movement state of the hydraulic cylinder.

[0047] The hydraulic cylinder part is responsible for realizing the load force effect and signal collection function. The external load signal is input to the pressure conversion element through the signal input element, which converts the signal into actual force and drives the hydraulic cylinder body to move. At the same time, the displacement signal acquisition element is responsible for real-time detection of the displacement of the hydraulic cylinder piston rod, and the load force detection element is used to capture the changes in the external load force, thereby providing the system with real-time signal feedback on load and displacement. The real-time feedback signals of load and displacement are respectively transmitted to the signal feedback control part, combined with the pressure signal from the flow pressure detection device received in real time by the signal feedback control part, and after calculation, they are used to dynamically adjust the output displacement of the variable pump and the oil flow direction in the three-position four-way solenoid valve, to ensure that the system can maintain the stability and efficiency of the hydraulic cylinder action under different load conditions.

[0048] The signal feedback control part is the core of the whole system, responsible for signal calculation, comparison and adjustment. The control signal is provided by the input signal source. The actual signal input operation module performs comprehensive calculation on the displacement signal of the hydraulic cylinder piston rod movement and the pressure signal before the inlet of the three-position four-way solenoid valve, and then uniformly processes it through the first signal comparison point, the power displacement conversion module, and the second signal comparison point. The processed signal is input to the PID controller. The PID controller further optimizes the signal stability to make the output signal more stable and reliable. The bidirectional signal exchange module selects the input signal according to the manual instruction K value, thereby adjusting the action of the variable pump and the solenoid valve according to the load change. Specifically, the manual instruction K value of the signal feedback control part is set to other values ​​except -1, 0, and 1. At this time, the bidirectional signal exchange module is connected to the PID control path of the lower path, and the three-position four-way solenoid valve is controlled by the PID controller through the first signal gain module. The control signal will change according to the increase or decrease of the signal source; when the K value is 0, the bidirectional signal exchange module is in the 0 position, corresponding to the middle position of the three-position four-way solenoid valve; when the K value is -1 or 1, the bidirectional signal exchange module corresponds to -1 or 1, -1 corresponds to the right position of the three-position four-way solenoid valve, and 1 corresponds to the left position of the three-position four-way solenoid valve, that is, the manual instruction K can directly control the three-position four-way solenoid valve.

[0049] Finally, the first signal gain module and the second signal gain module respectively convert the processed control signal into feedback signals and input them into the system, realizing efficient closed-loop feedback of external load force changes and hydraulic cylinder control, ensuring the accuracy and efficiency of the entire system under complex working conditions.

[0050] The above is only an embodiment of the present invention, and does not limit the present invention in any form. The present invention can also have other forms of embodiments according to the above structures and functions, which are not listed one by one. Therefore, any simple modification, equivalent change and modification made by any technician familiar with the profession to the above embodiment according to the technical essence of the present invention without departing from the scope of the technical solution of the present invention still falls within the scope of the technical solution of the present invention.

Claims

1. A hydraulic cylinder variable pump control system based on load force feedback, characterized in that: It includes a hydraulic oil circuit part, a hydraulic cylinder part, and a signal feedback control part; the hydraulic oil circuit part includes an oil tank, a motor, a variable pump, a three-position four-way solenoid valve, and a flow pressure detection device; the hydraulic cylinder part includes a hydraulic cylinder, a load, a displacement sensor, and a force sensor; the signal feedback control part includes an actual power converter, a theoretical power converter, a first signal comparison point, a power displacement converter, a second signal comparison point, a PID controller, a first signal gain device, and a second signal gain device; The motor is electrically connected to the variable pump, the input end of the variable pump is connected to the oil tank, the output end is connected to the P port of the three-position four-way solenoid valve, the A port of the three-position four-way solenoid valve is connected to the rodless cavity of the hydraulic cylinder, the B port is connected to the rod cavity of the hydraulic cylinder, and the T port is connected to the oil tank; A flow pressure detection device is connected to the pipeline between the variable pump and the three-position four-way solenoid valve, and the flow pressure detection device is used to input the pressure signal detected before the inlet of the three-position four-way solenoid valve into the actual power converter in the signal feedback control part; Hydraulic cylinders are used to drive loads; The displacement sensor is used to collect the displacement signal of the hydraulic cylinder piston rod movement and transmit the displacement signal to the actual power converter. The actual power converter is used to calculate the displacement signal of the hydraulic cylinder piston rod movement and the pressure signal before the inlet of the three-position four-way solenoid valve, and transmit the actual power signal obtained after the calculation to the first signal comparison point; the force sensor is used to detect the load force change signal and transmit the signal to the theoretical power converter. The theoretical power converter calculates the load force change signal and also transmits the theoretical power signal obtained after the calculation to the first signal comparison point; the first signal comparison point performs a difference operation on the power signals respectively transmitted by the actual power converter and the theoretical power converter to obtain a power correction signal, and transmits the power correction signal to the power displacement converter. The power displacement converter converts the input power correction signal into a displacement correction signal and transmits it to the second signal comparison point. The second signal comparison point adds the displacement correction signal and the manually input default displacement instruction and transmits the calculation result to the PID controller. The output signal of the PID controller is transmitted to the variable pump through the first signal gain device and to the control end of the three-position four-way solenoid valve through the second signal gain device.

2. The hydraulic cylinder variable pump control system based on load force feedback according to claim 1, characterized in that: The hydraulic oil circuit also includes an overflow valve, which is connected to a pipeline between the variable pump and the three-position four-way solenoid valve.

3. The hydraulic cylinder variable pump control system based on load force feedback according to claim 1, characterized in that: The hydraulic oil circuit also includes a variable throttle, which is arranged on a pipeline connecting the B port of the three-position four-way solenoid valve and the rod chamber of the hydraulic cylinder. The opening size of the variable throttle is adjusted by manual command.

4. The hydraulic cylinder variable pump control system based on load force feedback according to claim 1, characterized in that: The signal feedback control part also includes a two-way switch, which is arranged between the PID controller and the second signal gain device. The two-way switch selects the input signal according to the manual instruction K value. When the manual instruction K value is 0, the two-way switch is correspondingly placed in the 0 position. At this time, it is manual control, and the valve core of the three-position four-way solenoid valve is in the middle position; when the manual instruction K value is -1, the two-way switch is correspondingly placed in the -1 position. At this time, it is manual control, and the valve core of the three-position four-way solenoid valve is in the right position; when the manual instruction K value is 1, the two-way switch is correspondingly placed in the 1 position. At this time, it is manual control, and the valve core of the three-position four-way solenoid valve is in the left position; when the manual instruction K value is other values ​​except 0, -1, and 1, the two-way switch is connected to the output end of the PID controller, and the system is automatically controlled.

5. The hydraulic cylinder variable pump control system based on load force feedback according to claim 1, characterized in that: The internal algorithm formula of the actual power converter is: Where, K: leakage coefficient; A: effective working area of ​​the piston; t: time; x: collected displacement signal of the hydraulic cylinder piston rod; y: pressure signal detected before the inlet of the three-position four-way solenoid valve, f (x,y) is the actual power.

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