Control device and method for action speed of hydraulic oil cylinder and engineering machinery

Abstract

The invention discloses a hydraulic oil cylinder action speed control device and method and engineering machinery, a hydraulic oil way where a hydraulic oil cylinder is located comprises a proportional electromagnetic valve and an oil tank, one side of the proportional electromagnetic valve is communicated with the oil tank, the other side of the proportional electromagnetic valve is communicated with the hydraulic oil cylinder, and the control device comprises a temperature detection part, a flow detection part and a control unit; the temperature detection piece is used for detecting the temperature of hydraulic oil and sending a temperature signal; the flow detection piece is installed on a hydraulic oil way and used for detecting the hydraulic oil flow of the hydraulic oil cylinder and sending a flow signal. And the control unit is electrically connected with the flow detection piece, the temperature detection piece and the proportional electromagnetic valve, and the control unit is used for adjusting the opening degree of the proportional electromagnetic valve according to the temperature of the hydraulic oil and the change value of the flow. The influence rule of the hydraulic oil temperature and flow on the oil cylinder speed is fully considered, the precision and stability of hydraulic oil cylinder action speed control are remarkably improved, and therefore the working performance and reliability of a whole hydraulic system are improved.

Description

Technical Field

[0001] The present application belongs to the technical field of engineering machinery, and specifically relates to a control device and method for the action speed of a hydraulic cylinder and engineering machinery. Background Art

[0002] In construction machinery, the existing technology generally controls the speed of the hydraulic cylinder in the machinery by adjusting the current of the proportional solenoid valve. This method does not take into account the huge impact of temperature on hydraulic oil. As the temperature of the hydraulic oil increases, the viscosity will decrease and the fluidity will increase. If the current controlling the proportional solenoid valve remains unchanged, the cylinder speed may increase. Similarly, when the flow rate increases, the cylinder speed will also increase, making it difficult to ensure the consistency of the movement speed. Therefore, in a low temperature environment, it will be obvious that the movement speed of the hydraulic cylinder has slowed down, and completing the corresponding task will increase the time cost and fuel consumption. Summary of the invention

[0003] The purpose of the present application is to provide a control device and method for the action speed of a hydraulic cylinder and engineering machinery, so as to improve the accuracy and stability of the control of the action speed of the hydraulic cylinder.

[0004] In order to achieve the above-mentioned purpose, the present application provides, on one hand, a control device for the action speed of a hydraulic cylinder, wherein the hydraulic cylinder is arranged on a hydraulic oil circuit, wherein the hydraulic oil circuit comprises a proportional solenoid valve and an oil tank, wherein one side of the proportional solenoid valve is connected to the oil tank, and the other side is connected to the hydraulic cylinder, and the control device for the action speed of the hydraulic cylinder comprises:

[0005] Temperature detection element, used to detect the temperature of hydraulic oil and send temperature signal;

[0006] A flow detection component installed on the hydraulic oil circuit, the flow detection component is used to detect the hydraulic oil flow of the hydraulic cylinder and send a flow signal; and

[0007] A control unit is electrically connected to the flow detection element, the temperature detection element and the proportional solenoid valve, and the control unit is used to adjust the opening of the proportional solenoid valve according to the change in the temperature and flow of the hydraulic oil.

[0008] In some embodiments, the temperature detecting component is a temperature sensor, and the temperature sensor is installed in the oil tank.

[0009] In some embodiments, the flow detection component is a flow sensor, and the flow sensor is installed on the hydraulic pipeline between the proportional solenoid valve and the hydraulic cylinder.

[0010] A second aspect of the present application provides a method for controlling the action speed of a hydraulic cylinder, which is applied to the control device as described above. The control method comprises the following steps:

[0011] Obtaining a preset current of the proportional solenoid valve;

[0012] During the operation of the hydraulic cylinder, the current temperature and current flow rate of the hydraulic oil are monitored in real time;

[0013] Calculating an actual current value of the proportional solenoid valve in a current state according to the current temperature, the current flow rate and a preset current of the proportional solenoid valve;

[0014] The current opening of the proportional solenoid valve is adjusted according to the actual current value of the proportional solenoid valve.

[0015] In some embodiments, the step of adjusting the current opening of the proportional solenoid valve according to the actual current value of the proportional solenoid valve includes:

[0016] During the operation of the hydraulic cylinder, the temperature and flow changes of the hydraulic oil are monitored in real time;

[0017] When the hydraulic oil temperature rises and the flow rate remains unchanged, the current reduction value of the proportional solenoid valve is calculated according to the preset formula;

[0018] The opening of the proportional solenoid valve is controlled to decrease according to the current reduction value of the proportional solenoid valve, so as to reduce the action speed of the hydraulic cylinder.

[0019] In some embodiments, the step of adjusting the current opening of the proportional solenoid valve according to the actual current value of the proportional solenoid valve includes:

[0020] During the operation of the hydraulic cylinder, the temperature and flow changes of the hydraulic oil are monitored in real time;

[0021] When the hydraulic oil temperature remains unchanged and the flow rate changes, the current change value of the proportional solenoid valve is calculated according to a preset formula;

[0022] The opening of the proportional solenoid valve is changed according to the current change value of the proportional solenoid valve, so that the actual action speed of the hydraulic cylinder reaches the preset action speed.

[0023] In some embodiments, the step of adjusting the current opening of the proportional solenoid valve according to the actual current value of the proportional solenoid valve includes:

[0024] During the operation of the hydraulic cylinder, the temperature of the hydraulic oil and the change of the oil temperature are obtained in real time;

[0025] When the temperature of the hydraulic oil increases and the flow rate changes, the current change value of the proportional solenoid valve is calculated according to a preset formula;

[0026] The opening of the proportional solenoid valve is changed according to the current change value of the proportional solenoid valve, so that the actual action speed of the hydraulic cylinder reaches the preset action speed.

[0027] In some implementations, the control current of the proportional solenoid valve can be calculated using the following formula:

[0028] I=-k·ΔQ+I0·e -a(T-T0)

[0029] Among them, I is the actual maximum control current of the proportional solenoid valve; I0 is the maximum preset current of the proportional solenoid valve at the reference temperature; a is the hydraulic parameter of the hydraulic oil circuit; T is the current temperature of the hydraulic oil; T0 is the reference temperature of the hydraulic oil; k is the flow change coefficient; ΔQ is the flow change value.

[0030] In some embodiments, after the step of obtaining the preset current of the proportional solenoid valve, the step further includes:

[0031] Determining whether the temperature detection component and the flow detection component are normal;

[0032] When the temperature detection component and the flow detection component are abnormal, the hydraulic cylinder is controlled to stop moving.

[0033] A third aspect of the present application provides an engineering machine, comprising a hydraulic cylinder and a control device for the movement speed of the hydraulic cylinder as described above.

[0034] Through the above technical solution, a temperature detector and a flow detector are installed on the hydraulic oil circuit, and a control unit electrically connected to the temperature detector and the flow detector is set. During the operation of the hydraulic cylinder, the temperature and flow rate of the hydraulic oil in the hydraulic oil circuit are obtained in real time through the temperature detector and the flow detector, and the corresponding size change signal is sent out by comparing the temperature and flow changes in the previous and subsequent time periods. Then, the control unit adjusts the opening of the proportional solenoid valve according to the change in the temperature and flow rate of the hydraulic oil, thereby achieving precise control of the speed of the hydraulic cylinder. Through the above technical solution, the present application can effectively overcome the adverse effects of changes in the temperature and flow rate of the hydraulic oil on the hydraulic cylinder, significantly improve the accuracy and stability of the hydraulic cylinder operation speed control, and thus improve the working performance and reliability of the entire hydraulic system.

[0035] Other features and advantages of the embodiments of the present application will be described in detail in the subsequent detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The accompanying drawings are used to provide a further understanding of the embodiments of the present application and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the embodiments of the present application, but do not constitute a limitation on the embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without creative work. In the drawings:

[0037] Figure 1 It is a flow chart of the method for controlling the action speed of the hydraulic cylinder of the present application. DETAILED DESCRIPTION

[0038] The specific implementation of the present application is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the present application, and is not used to limit the present application.

[0039] The following describes a device and method for controlling the action speed of a hydraulic cylinder and an engineering machine according to the present application with reference to the accompanying drawings.

[0040] Since the power system can drive the hydraulic pump to work, in the hydraulic system, the flow of hydraulic oil is controlled by controlling the opening of the proportional solenoid valve to achieve control of the hydraulic cylinder's movement speed. In order to solve the adverse effects of insufficient control accuracy and hydraulic oil temperature changes, the present application provides a control device for the hydraulic cylinder's movement speed, the hydraulic cylinder is arranged on a hydraulic oil circuit, the hydraulic oil circuit includes a proportional solenoid valve and an oil tank, one side of the proportional solenoid valve is connected to the oil tank, and the other side is connected to the hydraulic cylinder, the control device for the hydraulic cylinder's movement speed includes a temperature detection component, a flow detection component and a control unit; the temperature detection component is used to detect the temperature of the hydraulic oil and send a temperature signal; the flow detection component is installed on the hydraulic oil circuit, the flow detection component is used to detect the hydraulic oil flow of the hydraulic cylinder and send a flow signal; the control unit is electrically connected to the flow detection component, the temperature detection component and the proportional solenoid valve, and the control unit is used to adjust the opening of the proportional solenoid valve according to the change in the temperature and flow of the hydraulic oil.

[0041] In the present application, by installing a temperature detector and a flow detector on the hydraulic oil circuit, during the operation of the hydraulic cylinder, the temperature and flow rate of the hydraulic oil on the hydraulic oil circuit are obtained in real time through the temperature detector and the flow detector, and by comparing the temperature and flow rate changes before and after the time, a corresponding size change signal is issued, and then the control unit adjusts the opening of the proportional solenoid valve according to the change value of the temperature and flow rate of the hydraulic oil, so as to achieve precise control of the speed of the hydraulic cylinder. Through the above technical scheme, the present application can effectively overcome the adverse effects of hydraulic oil temperature and flow rate changes on the hydraulic cylinder, significantly improve the accuracy and stability of the hydraulic cylinder action speed control, thereby improving the working performance and reliability of the entire hydraulic system, and is widely applicable to various industrial equipment and mechanical systems with high requirements for hydraulic cylinder speed control.

[0042] In some embodiments, the temperature detection element is a temperature sensor, which is installed in the oil tank and can detect the specific value of the temperature of the hydraulic oil in the hydraulic oil tank. In this application, by installing the temperature sensor in the oil tank, the hydraulic oil temperature obtained at this time is the most accurate, and the temperature will not be affected by the hydraulic oil in the pipeline transportation process, resulting in deviation in the detection result.

[0043] In some embodiments, the flow detection element is a flow sensor, which is installed on the hydraulic pipeline between the proportional solenoid valve and the hydraulic cylinder. The flow sensor can measure the hydraulic oil flow in the hydraulic pipeline before flowing into the hydraulic cylinder and can send the flow value to the control unit.

[0044] In addition, the control device for the hydraulic cylinder movement speed also includes a display screen that is communicatively connected to the control unit. The display screen can display the temperature, flow value and other relevant technical parameters of the hydraulic oil to facilitate the operator to perform real-time monitoring of the hydraulic oil circuit.

[0045] Of course, in other embodiments, the temperature detection element and the flow detection element are not limited to the sensor forms listed above, and other detection element structures that can communicate and interact with the control unit can also be used. As long as the structural form can obtain the temperature and flow of the hydraulic oil in real time, it is within the protection scope of this application and will not be described in detail here.

[0046] The second aspect of the present application provides a method for controlling the action speed of a hydraulic cylinder, which is applied to the control device as described above. Figure 1 As shown, the control method comprises the steps of:

[0047] S10: Obtaining the preset current of the proportional solenoid valve;

[0048] S20: During the operation of the hydraulic cylinder, the current temperature and current flow of the hydraulic oil are monitored in real time;

[0049] S30: Calculating the actual current value of the proportional solenoid valve in the current state according to the current temperature, the current flow rate and the preset current of the proportional solenoid valve;

[0050] S40: adjusting the current opening of the proportional solenoid valve according to the actual current value of the proportional solenoid valve.

[0051] This application tests different temperature changes and different hydraulic oil flow changes, calculates the flow required for the hydraulic cylinder to move at the same speed, and then controls the valve opening by sending different control currents through the controller, thereby achieving relatively accurate control. In the control method of this embodiment, the influence of hydraulic oil temperature and flow on the hydraulic cylinder speed is fully considered, and stable control of the hydraulic cylinder speed is achieved.

[0052] In some embodiments, the step of adjusting the current opening of the proportional solenoid valve according to the actual current value of the proportional solenoid valve includes:

[0053] During the operation of the hydraulic cylinder, the temperature and flow changes of the hydraulic oil are monitored in real time;

[0054] When the hydraulic oil temperature rises and the flow rate remains unchanged, the current reduction value of the proportional solenoid valve is calculated according to the preset formula;

[0055] The opening of the proportional solenoid valve is controlled to decrease according to the current reduction value of the proportional solenoid valve to reduce the action speed of the hydraulic cylinder.

[0056] In the hydraulic system where the hydraulic cylinder is located, the preset ideal movement speed of the hydraulic cylinder piston rod is V0. When the temperature T of the hydraulic oil increases and the flow Q remains unchanged, the temperature sensor detects the temperature increase value ΔT of the hydraulic oil, and the flow sensor detects that the flow Q remains unchanged. At this time, the viscosity of the hydraulic oil increases, causing the movement speed of the hydraulic cylinder to exceed the preset speed. In order to ensure that the movement speed of the hydraulic cylinder is within the appropriate range, the control unit calculates the current change value ΔI required to reduce the proportional solenoid valve according to the preset formula to reduce the opening of the proportional solenoid valve, thereby reducing the movement speed of the lifting cylinder to approach or reach V0. Similarly, when the flow Q changes and the temperature T of the hydraulic oil remains unchanged, the control unit will also make corresponding current adjustments to ensure the precise control of the lifting hydraulic cylinder. When the temperature T and flow Q of the hydraulic oil change at the same time, the current I is also adjusted.

[0057] In some embodiments, the step of adjusting the current opening of the proportional solenoid valve according to the actual current value of the proportional solenoid valve includes:

[0058] During the operation of the hydraulic cylinder, the temperature and flow changes of the hydraulic oil are monitored in real time;

[0059] When the hydraulic oil temperature remains unchanged and the flow rate changes, the current change value of the proportional solenoid valve is calculated according to the preset formula;

[0060] The opening of the proportional solenoid valve is changed according to the current change value of the proportional solenoid valve so that the actual movement speed of the hydraulic cylinder reaches the preset movement speed.

[0061] When the temperature of the hydraulic oil remains unchanged and the flow rate decreases, the flow rate of the hydraulic oil can no longer meet the preset action speed requirement of the hydraulic cylinder, causing the extension and retraction speed of the piston rod of the hydraulic cylinder to slow down. The current of the proportional solenoid valve calculated by the preset formula becomes larger, and the opening of the proportional solenoid valve is increased according to the required increase in the current, so that the actual action speed of the hydraulic cylinder reaches the preset action speed, so that the action of the hydraulic cylinder remains within the preset precision range.

[0062] When the temperature of the hydraulic oil remains unchanged and the flow rate increases, the flow rate of the hydraulic oil exceeds the preset flow rate, causing the movement speed of the hydraulic cylinder to exceed the preset speed. At this time, the preset formula is used to calculate that the current of the proportional solenoid valve needs to be reduced, so that the opening of the proportional solenoid valve can be reduced according to the required reduction value of the current, so that the actual movement speed of the hydraulic cylinder reaches the preset movement speed, so that the movement of the hydraulic cylinder remains within the preset precision range.

[0063] In some embodiments, the step of adjusting the current opening of the proportional solenoid valve according to the actual current value of the proportional solenoid valve includes:

[0064] During the operation of the hydraulic cylinder, the temperature of the hydraulic oil and its changes are obtained in real time;

[0065] When the hydraulic oil temperature rises and the flow rate changes, the current change value of the proportional solenoid valve is calculated according to the preset formula;

[0066] The opening of the proportional solenoid valve is changed according to the current change value of the proportional solenoid valve so that the actual movement speed of the hydraulic cylinder reaches the preset movement speed.

[0067] When the temperature of the hydraulic oil increases, the viscosity of the hydraulic oil will decrease, which may cause the speed of the hydraulic cylinder to increase. At this time, the control unit will reduce the opening of the proportional solenoid valve accordingly, thereby reducing the speed of the hydraulic cylinder and keeping it within the preset precision range. Similarly, when the flow rate changes, the control unit will also make corresponding current adjustments, and comprehensively consider the impact of the simultaneous changes of the two, so as to achieve stable control of the speed of the hydraulic cylinder. Similarly, when the flow rate changes, the control unit will also make corresponding current adjustments, and comprehensively consider the impact of the simultaneous changes of the two, so as to achieve stable control of the speed of the cylinder. Previously, through repeated tests, the influence of temperature and flow changes on the cylinder speed has been summarized, and the ideal calculation method has been estimated.

[0068] When the temperature of the hydraulic oil increases and the flow rate decreases, the increase in temperature will cause the viscosity of the hydraulic oil to decrease, which may cause the speed of the hydraulic cylinder to increase; and the decrease in the flow rate of the hydraulic oil will cause the speed of the hydraulic cylinder to be lower than the preset speed. Therefore, under this working condition, it is necessary to control the opening of the proportional solenoid valve according to the result calculated according to the preset formula, so as to achieve stable control of the speed of the hydraulic cylinder.

[0069] When the temperature of the hydraulic oil rises and the flow rate increases, the flow rate of the hydraulic oil exceeds the preset flow rate, and the viscosity of the hydraulic oil decreases, causing the movement speed of the hydraulic cylinder to exceed the preset speed. At this time, the preset formula is used to calculate that the current of the proportional solenoid valve needs to be reduced, so that the opening of the proportional solenoid valve can be reduced according to the required reduction value of the current, so that the actual movement speed of the hydraulic cylinder reaches the preset movement speed, so that the movement of the hydraulic cylinder remains within the preset precision range.

[0070] Specifically, the control current of the proportional solenoid valve can be calculated by the following formula:

[0071] I=-k·ΔQ+I0·e -a(T-T0)

[0072] Among them, I is the actual maximum control current of the proportional solenoid valve; I0 is the maximum preset current of the proportional solenoid valve at the reference temperature; a is the hydraulic parameter of the hydraulic oil circuit, which is determined by the structure of the hydraulic system; T is the current temperature of the hydraulic oil; T0 is the reference temperature of the hydraulic oil; k is the flow change coefficient; ΔQ is the flow change value.

[0073] In some embodiments, after the step of obtaining the preset current of the proportional solenoid valve, the step further includes:

[0074] Determine whether the temperature detection component and flow detection component are normal;

[0075] When the temperature detection component and the flow detection component are abnormal, the hydraulic cylinder is controlled to stop moving.

[0076] In this embodiment, after obtaining the preset current parameters of the proportional solenoid valve and before detecting the temperature and flow of the hydraulic oil, it is necessary to determine whether the temperature detection component and the flow detection component are in a normal working state. When it is determined that the temperature detection component and the flow detection component are abnormal, an alarm is used to remind the operator and the control unit controls the hydraulic oil circuit to stop supplying oil to the hydraulic cylinder. When the temperature detection component and the flow detection component are in a normal working state, the next detection process is performed.

[0077] The third aspect of the present application provides an engineering machine, including a hydraulic cylinder and a control device for the hydraulic cylinder movement speed as described above. The engineering machine can be a boom-type aerial work platform, and the hydraulic cylinder is a lifting cylinder of the main arm, and the main arm can be stably lifted by controlling the movement speed of the lifting cylinder. In addition, since the engineering machine adopts all the embodiments of the above-mentioned control device, it has all the beneficial effects brought by the above-mentioned control device, which will not be described in detail here.

[0078] In the description of the present application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present application, "plurality" means at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0079] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0080] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0081] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A control device for the action speed of a hydraulic cylinder, characterized in that: The hydraulic cylinder is arranged on a hydraulic oil circuit, the hydraulic oil circuit includes a proportional solenoid valve and an oil tank, one side of the proportional solenoid valve is connected to the oil tank, and the other side is connected to the hydraulic cylinder, and the control device of the hydraulic cylinder action speed includes: Temperature detection element, used to detect the temperature of hydraulic oil and send temperature signal; A flow detection component installed on the hydraulic oil circuit, the flow detection component is used to detect the hydraulic oil flow of the hydraulic cylinder and send a flow signal; and A control unit is electrically connected to the flow detection element, the temperature detection element and the proportional solenoid valve, and the control unit is used to adjust the opening of the proportional solenoid valve according to the change in the temperature and flow of the hydraulic oil.

2. The control device for the hydraulic cylinder action speed according to claim 1, characterized in that: The temperature detection component is a temperature sensor, and the temperature sensor is installed in the oil tank.

3. The control device for the hydraulic cylinder action speed according to claim 1, characterized in that: The flow detection component is a flow sensor, and the flow sensor is installed on the hydraulic pipeline between the proportional solenoid valve and the hydraulic cylinder.

4. A method for controlling the action speed of a hydraulic cylinder, characterized in that: Applied to the control device according to any one of claims 1 to 3, the method for controlling the action speed of the hydraulic cylinder comprises the steps of: Obtaining a preset current of the proportional solenoid valve; During the operation of the hydraulic cylinder, the current temperature and current flow rate of the hydraulic oil are monitored in real time; Calculating an actual current value of the proportional solenoid valve in a current state according to the current temperature, the current flow rate and a preset current of the proportional solenoid valve; The current opening of the proportional solenoid valve is adjusted according to the actual current value of the proportional solenoid valve.

5. The method for controlling the hydraulic cylinder movement speed according to claim 4, characterized in that: The step of adjusting the current opening of the proportional solenoid valve according to the actual current value of the proportional solenoid valve comprises: During the operation of the hydraulic cylinder, the temperature and flow changes of the hydraulic oil are monitored in real time; When the hydraulic oil temperature rises and the flow rate remains unchanged, the current reduction value of the proportional solenoid valve is calculated according to the preset formula; The opening of the proportional solenoid valve is controlled to decrease according to the current reduction value of the proportional solenoid valve, so as to reduce the action speed of the hydraulic cylinder.

6. The method for controlling the hydraulic cylinder movement speed according to claim 4, characterized in that: The step of adjusting the current opening of the proportional solenoid valve according to the actual current value of the proportional solenoid valve comprises: During the operation of the hydraulic cylinder, the temperature and flow changes of the hydraulic oil are monitored in real time; When the hydraulic oil temperature remains unchanged and the flow rate changes, the current change value of the proportional solenoid valve is calculated according to a preset formula; The opening of the proportional solenoid valve is changed according to the current change value of the proportional solenoid valve, so that the actual action speed of the hydraulic cylinder reaches the preset action speed.

7. The method for controlling the hydraulic cylinder movement speed according to claim 4, characterized in that: The step of adjusting the current opening of the proportional solenoid valve according to the actual current value of the proportional solenoid valve comprises: During the operation of the hydraulic cylinder, the temperature of the hydraulic oil and the change of the oil temperature are obtained in real time; When the temperature of the hydraulic oil increases and the flow rate changes, the current change value of the proportional solenoid valve is calculated according to a preset formula; The opening of the proportional solenoid valve is changed according to the current change value of the proportional solenoid valve, so that the actual action speed of the hydraulic cylinder reaches the preset action speed.

8. The method for controlling the hydraulic cylinder movement speed according to claim 4, characterized in that: The control current of the proportional solenoid valve can be calculated by the following formula: I=-k·ΔQ+I0·e -a(T-T0) Among them, I is the actual maximum control current of the proportional solenoid valve; I0 is the maximum preset current of the proportional solenoid valve at the reference temperature; a is the hydraulic parameter of the hydraulic oil circuit; T is the current temperature of the hydraulic oil; T0 is the reference temperature of the hydraulic oil; k is the flow change coefficient; ΔQ is the flow change value.

9. The method for controlling the hydraulic cylinder movement speed according to claim 4, characterized in that: After the step of obtaining the preset current of the proportional solenoid valve, the method further includes: Determining whether the temperature detection component and the flow detection component are normal; When the temperature detection component and the flow detection component are abnormal, the hydraulic cylinder is controlled to stop moving.

10. An engineering machine, characterized in that: It comprises a hydraulic cylinder and a control device for the hydraulic cylinder action speed according to any one of claims 1 to 3.

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