Electro-hydraulic servo system, control method and device thereof and computer readable storage medium

Abstract

The invention discloses an electro-hydraulic servo system, a control method and device of the electro-hydraulic servo system and a computer readable storage medium, and the control method of the electro-hydraulic servo system comprises the steps that a pressure feedback value of the electro-hydraulic servo system and a system target pressure value are obtained, and the pressure feedback value of the electro-hydraulic servo system and the system target pressure value are obtained according to the pressure feedback value and the system target pressure value; determining the pressure state of the electro-hydraulic servo system; according to the pressure state, adjusting a pressure ring parameter of the electro-hydraulic servo system to obtain a target pressure ring parameter; according to the pressure state, adjusting a speed ring parameter of the electro-hydraulic servo system to obtain a target speed ring parameter; and controlling the operation of the electro-hydraulic servo system based on the target pressure ring parameter and the target speed ring parameter. The technical problem that an electro-hydraulic servo system is unstable is solved.

Description

Technical Field

[0001] This invention relates to the field of electro-hydraulic servo system technology, and in particular to an electro-hydraulic servo system and its control method, device, and computer-readable storage medium. Background Technology

[0002] Electro-hydraulic servo systems have been widely used due to their advantages such as low energy loss, low power consumption, and low oil circuit temperature rise. The conventional control method for electro-hydraulic servo control systems is a three-loop PID (Proportional-Integral-Derivative) control, consisting of a pressure loop, a speed loop, and a current loop. This control structure can control the speed and pressure of the electro-hydraulic servo system.

[0003] Due to the diverse operating conditions of electro-hydraulic servo systems, it is difficult for the same set of control parameters to adapt to various operating conditions. For example, the same set of speed-pressure control parameters is difficult to adapt to various operating conditions of electro-hydraulic servo systems, which leads to pressure fluctuations, speed oscillations, and other issues, resulting in instability of the electro-hydraulic servo system. Summary of the Invention

[0004] The main objective of this invention is to provide an electro-hydraulic servo system and its control method, apparatus, and computer-readable storage medium, aiming to solve the technical problem of instability in electro-hydraulic servo systems.

[0005] To achieve the above objectives, the present invention provides a control method for an electro-hydraulic servo system, which acquires the pressure feedback value and the target pressure value of the electro-hydraulic servo system.

[0006] The pressure state of the electro-hydraulic servo system is determined based on the pressure feedback value and the system target pressure value.

[0007] Based on the pressure state, the pressure loop parameters of the electro-hydraulic servo system are adjusted to obtain the target pressure loop parameters, and the speed loop parameters of the electro-hydraulic servo system are adjusted to obtain the target speed loop parameters.

[0008] The electro-hydraulic servo system is controlled based on the target pressure loop parameters and the target speed loop parameters.

[0009] In one embodiment, the step of determining the pressure state of the electro-hydraulic servo system based on the pressure feedback value and the system target pressure value includes:

[0010] Determine the pressure error between the pressure feedback value and the system target pressure value;

[0011] The pressure deviation rate is obtained by calculating the ratio of the pressure error to the system target pressure value.

[0012] The pressure state is determined based on the pressure deviation rate and the preset pressure stability parameters.

[0013] In one embodiment, the step of determining the pressure state based on the pressure deviation rate and the preset pressure stability parameter includes:

[0014] When the absolute value of the pressure deviation rate is less than or equal to the preset pressure stability parameter, the pressure state is determined to be a pressure holding state.

[0015] When the absolute value of the pressure deviation rate is greater than the preset pressure stability parameter, the pressure state is determined to be a non-pressure holding state.

[0016] In one embodiment, the pressure loop parameters include a pressure proportional parameter and a pressure integral parameter, and the target pressure loop parameters include a target pressure proportional parameter and a target pressure integral parameter;

[0017] The step of adjusting the pressure loop parameters of the electro-hydraulic servo system according to the pressure state to obtain the target pressure loop parameters includes:

[0018] When the pressure state is a pressure holding state, the target pressure ratio parameter is obtained by increasing the pressure ratio parameter according to the first preset pressure holding coefficient.

[0019] The target pressure integral parameter is obtained by increasing the pressure integral parameter based on the first preset pressure holding coefficient.

[0020] In one embodiment, the pressure loop parameters include a pressure proportional parameter and a pressure integral parameter, and the target pressure loop parameters include a target pressure proportional parameter and a target pressure integral parameter;

[0021] The step of adjusting the pressure loop parameters of the electro-hydraulic servo system according to the pressure state to obtain the target pressure loop parameters includes:

[0022] When the pressure state is a non-pressure-holding state, the pressure proportional parameter is used as the target pressure proportional parameter, and the pressure integral parameter is used as the target pressure integral parameter.

[0023] In one embodiment, the velocity loop parameters include a velocity proportional parameter and a velocity integral parameter, and the target velocity loop parameters include a target velocity proportional parameter and a target velocity integral parameter;

[0024] The step of adjusting the speed loop parameters of the electro-hydraulic servo system according to the pressure state to obtain the target speed loop parameters includes:

[0025] When the pressure state is a pressure holding state, the speed ratio parameter is increased according to the second preset pressure holding coefficient to obtain the target speed ratio parameter;

[0026] Based on the second preset pressure holding coefficient, the speed integral parameter is increased to obtain the target speed integral parameter.

[0027] In one embodiment, the velocity loop parameters include a velocity proportional parameter and a velocity integral parameter, and the target velocity loop parameters include a target velocity proportional parameter and a target velocity integral parameter;

[0028] The step of adjusting the speed loop parameters of the electro-hydraulic servo system according to the pressure state to obtain the target speed loop parameters includes:

[0029] When the pressure state is a non-pressure-holding state, the speed proportional parameter is used as the target speed proportional parameter, and the speed integral parameter is used as the target speed integral parameter.

[0030] The present invention also provides a control device for an electro-hydraulic servo system, the control device comprising:

[0031] The acquisition module is used to acquire the pressure feedback value and the target pressure value of the electro-hydraulic servo system, and determine the pressure state of the electro-hydraulic servo system based on the pressure feedback value and the target pressure value.

[0032] The first determining module is used to adjust the pressure loop parameters of the electro-hydraulic servo system according to the pressure state to obtain the target pressure loop parameters;

[0033] The second determining module is used to adjust the speed loop parameters of the electro-hydraulic servo system according to the pressure state to obtain the target speed loop parameters;

[0034] The control module is used to control the operation of the electro-hydraulic servo system based on the target pressure loop parameters and the target speed loop parameters.

[0035] The present invention also provides an electro-hydraulic servo system, including a controller and a motor, wherein the controller is used to implement the steps of the control method of the electro-hydraulic servo system as described above.

[0036] The present invention also provides a computer-readable storage medium storing a control program for an electro-hydraulic servo system that can run on a processor. The control program for the electro-hydraulic servo system is invoked by the processor to implement the steps of the control method for the electro-hydraulic servo system as described above.

[0037] This invention provides a control method for an electro-hydraulic servo system, which can achieve at least the following technical effects: The pressure state of the electro-hydraulic servo system can be determined based on the pressure feedback value and the target pressure value. Since the pressure feedback value reflects the pressure experienced by the electro-hydraulic servo system, and the target pressure value reflects the pressure the electro-hydraulic servo system expects to reach, the pressure state of the electro-hydraulic servo system can be determined based on the pressure feedback value and the target pressure value. Then, the pressure loop parameters and speed loop parameters of the electro-hydraulic servo system can be adjusted according to the pressure state to obtain the target pressure loop parameters and target speed loop parameters, thereby controlling the electro-hydraulic servo system to operate according to the target pressure loop parameters and target speed loop parameters.

[0038] Because when the pressure state changes, but the pressure loop parameters and velocity loop parameters remain unchanged, the electro-hydraulic servo system will still operate according to the original pressure loop parameters and velocity loop parameters. This can lead to the electro-hydraulic servo system being unable to adapt to the changed pressure state, potentially resulting in pressure fluctuations and velocity oscillations. Therefore, this invention adjusts the pressure loop parameters and velocity loop parameters according to the pressure state, allowing these parameters to change with the pressure state. This enables the electro-hydraulic servo system to adapt to changes in pressure state, ensuring the stability of the electro-hydraulic servo system's operation and avoiding the instability caused by using the same set of pressure loop parameters and velocity loop parameters under different operating conditions (e.g., the target pressure value and detected pressure feedback value may differ under different operating conditions, leading to different pressure states). Attached Figure Description

[0039] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0040] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1 This is a flowchart illustrating an embodiment of the control method for the electro-hydraulic servo system of the present invention.

[0042] Figure 2 This is a flowchart illustrating another embodiment of the control method for the electro-hydraulic servo system of the present invention;

[0043] Figure 3 This is a flowchart illustrating another embodiment of the control method for the electro-hydraulic servo system of the present invention.

[0044] Figure 4 This is a schematic diagram of the electro-hydraulic servo system in the control method of the electro-hydraulic servo system of the present invention;

[0045] Figure 5 This is a schematic diagram of the module structure of the control device of the electro-hydraulic servo system according to an embodiment of the present invention;

[0046] Figure 6 This is a schematic diagram of the hardware operating environment involved in an embodiment of the present invention.

[0047] The objectives, features, and advantages of this invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0048] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0049] The conventional control method of the electro-hydraulic servo control system is a three-loop PID control consisting of a pressure loop, a speed loop, and a current loop. The pressure command corresponding to the pressure loop can be obtained from the main control PLC (Programmable Logic Controller) of the electro-hydraulic servo system. The PID controller of the pressure loop outputs a speed command based on the pressure feedback value and the pressure command. The speed feedback of the speed loop is obtained through the motor encoder. The PID controller of the speed loop combines the speed command and the speed feedback to output a current command. The PID controller of the current loop acts on the motor of the electro-hydraulic servo system based on the current command and the acquired current voltage command, thus realizing the three-loop PID control of the pressure loop, speed loop, and current loop.

[0050] Due to the diverse operating conditions of electro-hydraulic servo systems, the same set of pressure and speed control parameters is difficult to adapt to various operating conditions. For example, different pressure states of electro-hydraulic servo systems can cause problems such as pressure fluctuations and speed oscillations, resulting in instability of the electro-hydraulic servo system and thus affecting the processing effect of the corresponding products.

[0051] To address this, the present invention proposes a control method for an electro-hydraulic servo system. This method adjusts the pressure loop parameters and velocity loop parameters of the electro-hydraulic servo system based on its pressure state to obtain target pressure loop parameters and velocity loop parameters. This allows the electro-hydraulic servo system to adapt to changes in pressure state, avoiding the use of the original pressure loop parameters and velocity loop parameters after pressure changes, thus preventing pressure fluctuations and velocity oscillations in the electro-hydraulic servo system.

[0052] Based on this, the present invention proposes a control method for an electro-hydraulic servo system according to a first embodiment, please refer to... Figure 1 The control method of the electro-hydraulic servo system includes steps S10 to S40:

[0053] Step S10: Obtain the pressure feedback value and the target pressure value of the electro-hydraulic servo system, and determine the pressure state of the electro-hydraulic servo system based on the pressure feedback value and the target pressure value.

[0054] It should be noted that an electro-hydraulic servo system is a type of hydraulic control system. This system includes a motor, which can be a permanent magnet synchronous motor. The pressure feedback value is the pressure value collected by the pressure sensor of the electro-hydraulic servo system, reflecting the pressure value experienced within the system. Products that can utilize an electro-hydraulic servo system include injection molding machines.

[0055] The system target pressure value refers to the pressure value expected by the electro-hydraulic servo system. The system target pressure value can be obtained from the pressure command, which can be issued by the main control PLC of the electro-hydraulic servo system.

[0056] For example, pressure feedback values ​​are acquired based on pressure sensors configured on the electro-hydraulic servo system; pressure commands are received, and the target system pressure value is determined from the pressure commands. In this embodiment, pressure feedback values ​​can be acquired in real time or periodically.

[0057] Pressure status describes the current pressure condition of an electro-hydraulic servo system. Pressure status can be divided into pressure-holding and non-pressure-holding states, representing two different operating conditions within the system. When the load on the electro-hydraulic servo system changes, the pressure status may also change, for example, transitioning from a pressure-holding state to a non-pressure-holding state. A pressure-holding state indicates that the current pressure of the electro-hydraulic servo system is relatively stable, while a non-pressure-holding state indicates that the current pressure is unstable, possibly in a pressure decrease or increase phase.

[0058] For example, the difference between the pressure feedback value and the system target pressure value can be calculated to obtain the pressure error. Based on the pressure error and the system target pressure value, the pressure state of the electro-hydraulic servo system can be determined. Since this embodiment can acquire the pressure feedback value in real time or periodically, the pressure state of the electro-hydraulic servo system can also be determined in real time or periodically. This facilitates timely detection of changes in the pressure state, allowing for timely adjustment of the pressure loop control parameters and speed loop control parameters based on the pressure state.

[0059] In a feasible embodiment, step S10 further includes steps S11 to S13:

[0060] Step S11: Determine the pressure error between the pressure feedback value and the system target pressure value;

[0061] Step S12: Calculate the ratio of pressure error to the system target pressure value to obtain the pressure deviation rate;

[0062] Step S13: Determine the pressure state based on the pressure deviation rate and preset pressure stability parameters.

[0063] It should be noted that pressure error can be used to describe the difference between the pressure feedback value and the system target pressure value. Pressure error can be positive or negative. The smaller the absolute value of the pressure deviation rate, the closer the pressure feedback value is to the system target pressure value; the larger the absolute value of the pressure deviation rate, the further the pressure feedback value is from the target pressure value. The preset pressure stability parameter represents the maximum tolerable pressure deviation rate.

[0064] For example, the difference between the pressure feedback value and the system target pressure value is calculated to obtain the pressure error. The ratio of the pressure error to the system target pressure value is calculated to obtain the pressure deviation rate. Based on the pressure deviation rate and preset pressure stability parameters, the pressure state of the electro-hydraulic servo system is determined. Because this embodiment can determine the pressure state by comparing the pressure deviation rate with the preset pressure stability parameters, rather than solely relying on the pressure error, the accuracy of determining the pressure state is improved. Even with different system target pressure values, the pressure state of the electro-hydraulic servo system can still be accurately determined.

[0065] In a feasible embodiment, step S13 further includes steps S131 to S132:

[0066] Step S131: When the absolute value of the pressure deviation rate is less than or equal to the preset pressure stabilization parameter, the pressure state is determined to be a pressure holding state.

[0067] Step S132: When the absolute value of the pressure deviation rate is greater than the preset pressure stabilization parameter, the pressure state is determined to be a non-pressure holding state.

[0068] It should be noted that when the absolute value of the pressure deviation rate is less than or equal to the preset pressure stability parameter, it indicates that the pressure deviation rate is within the tolerable error range of the electro-hydraulic servo system. This means the current pressure of the electro-hydraulic servo system is relatively stable, and the system is currently in a pressure-holding state. The pressure state can be represented by a status indicator, which can include a pressure-holding indicator and a non-pressure-holding indicator. For example, the pressure-holding state can be represented by a pressure-holding indicator; for instance, a pressure-holding indicator of 1 indicates that the electro-hydraulic servo system is in a pressure-holding state.

[0069] When the absolute value of the pressure deviation rate is greater than the preset pressure stability parameter, it indicates that the pressure deviation rate exceeds the tolerable error range of the electro-hydraulic servo system, meaning that the current pressure of the electro-hydraulic servo system is unstable, and the pressure state can be determined as a non-pressure holding state. The non-pressure holding state can be represented by a non-pressure holding indicator, which can be 0 to indicate that the electro-hydraulic servo system is in a non-pressure holding state.

[0070] For example, it is determined whether the absolute value of the pressure deviation rate is greater than the preset pressure stabilization parameter. When the absolute value of the pressure deviation rate is less than or equal to the preset pressure stabilization parameter, the pressure state is determined to be a pressure holding state, and the pressure holding state is represented by a pressure holding identifier. When the absolute value of the pressure deviation rate is greater than the preset pressure stabilization parameter, the pressure state is determined to be a non-pressure holding state, and the non-pressure holding state value is represented by a non-pressure holding state value.

[0071] Since different pressure states require different pressure loop parameters and speed loop parameters, this embodiment determines whether the electro-hydraulic servo system is in a pressure-holding state or a non-pressure-holding state, so as to facilitate the subsequent adjustment of pressure loop parameters and speed loop parameters based on different pressure states.

[0072] In one feasible embodiment, the preset pressure stability parameter is greater than or equal to a first preset threshold and less than or equal to a second preset threshold, wherein the first preset threshold is greater than 0.

[0073] The first preset threshold is less than the second preset threshold. The first and second preset thresholds can be obtained by debugging under actual working conditions. Preferably, the first preset threshold can be 0.1 and the second preset threshold can be 0.2.

[0074] In practical applications, the pressure feedback value of an electro-hydraulic servo system is unlikely to consistently maintain the target system pressure value. The pressure feedback value may fluctuate around the target pressure value. When the pressure feedback value fluctuates within a certain range corresponding to the target system pressure value, it indicates that the electro-hydraulic servo system is in a pressure-holding state. Therefore, a preset pressure stabilization parameter can be determined, and the pressure deviation rate of the electro-hydraulic servo system can be judged to be less than or equal to the preset pressure stabilization parameter, thus determining whether the pressure feedback value fluctuates within a certain range corresponding to the target system pressure value.

[0075] The second preset threshold should not be too large, so as to avoid the electro-hydraulic servo system being in a pressure-holding state when the pressure error between the pressure feedback value and the system target pressure value is too large, which would affect the subsequent adjustment of the pressure loop parameters and speed loop parameters.

[0076] Step S20: Adjust the pressure loop parameters of the electro-hydraulic servo system according to the pressure status to obtain the target pressure loop parameters;

[0077] Step S30: Adjust the speed loop parameters of the electro-hydraulic servo system according to the pressure state to obtain the target speed loop parameters;

[0078] It should be noted that the pressure loop parameters are the control parameters of the pressure loop in the electro-hydraulic servo system, and the speed loop parameters are the control parameters of the speed loop in the electro-hydraulic servo system. The pressure loop in the electro-hydraulic servo system can be used to control the internal pressure of the electro-hydraulic servo system, and the speed loop in the electro-hydraulic servo system is used to control the speed output of the electro-hydraulic servo system. For example, the speed loop can be used to control the motor speed in the electro-hydraulic servo system.

[0079] The pressure loop parameters include pressure proportional parameters and pressure integral parameters, while the speed loop parameters include speed proportional parameters and speed integral parameters.

[0080] Pressure loop parameters and speed loop parameters can be pre-configured in the electro-hydraulic servo system. When the electro-hydraulic servo system is started, a target system pressure value will be given. The pressure feedback value in the electro-hydraulic servo system may change from 0 to the target system pressure value. Before the target system pressure value is reached, the electro-hydraulic servo system will be in a non-pressure holding state. Therefore, the operation of the electro-hydraulic servo system can be controlled based on the pressure loop parameters and speed loop parameters at this time.

[0081] For example, based on the pressure state, the target pressure proportional parameter is obtained by adjusting the pressure proportional parameter, the target pressure integral parameter is obtained by adjusting the pressure integral parameter, the target speed proportional parameter is obtained by adjusting the speed proportional parameter, and the target integral parameter is obtained by adjusting the speed integral parameter. This allows the electro-hydraulic servo system to adapt to changes in pressure state.

[0082] In electro-hydraulic servo systems, the current loop is less affected by changes in operating conditions (pressure state), while the pressure and speed loops are more affected. Therefore, when operating conditions change, adjusting the pressure and speed loop parameters is sufficient. Even without adjusting the current loop parameters, the stable operation of the electro-hydraulic servo system can be guaranteed.

[0083] Step S40: Control the operation of the electro-hydraulic servo system based on the target pressure loop parameters and the target speed loop parameters.

[0084] It should be noted that once the target pressure loop parameters and target speed loop parameters are determined, the electro-hydraulic servo system can be controlled based on these parameters. The target pressure loop parameters include the target pressure integral parameter and the target pressure proportional parameter, and the target speed loop parameters include the target speed integral parameter and the target speed proportional parameter.

[0085] For example, the operation of an electro-hydraulic servo system is controlled based on the target pressure integral parameter, the target pressure proportional parameter, the target speed integral parameter, and the target proportional parameter.

[0086] The pressure state of the electro-hydraulic servo system can be determined based on the pressure feedback value and the target pressure value. Since the pressure feedback value reflects the pressure experienced by the electro-hydraulic servo system, while the target pressure value reflects the pressure the electro-hydraulic servo system is expected to reach, the pressure state of the electro-hydraulic servo system can be determined based on the pressure feedback value and the target pressure value. Then, the pressure loop parameters and speed loop parameters of the electro-hydraulic servo system can be adjusted according to the pressure state to obtain the target pressure loop parameters and target speed loop parameters, and the electro-hydraulic servo system can be controlled to operate according to the target pressure loop parameters and target speed loop parameters.

[0087] Because when the pressure state changes, but the pressure loop parameters and velocity loop parameters remain unchanged, the electro-hydraulic servo system will still operate according to the original pressure loop parameters and velocity loop parameters. This can lead to the electro-hydraulic servo system being unable to adapt to the changed pressure state, potentially resulting in pressure fluctuations and velocity oscillations. Therefore, this invention adjusts the pressure loop parameters and velocity loop parameters according to the pressure state, allowing these parameters to change with the pressure state. This enables the electro-hydraulic servo system to adapt to changes in pressure state, ensuring the stability of the electro-hydraulic servo system's operation and avoiding the instability caused by using the same set of pressure loop parameters and velocity loop parameters under different operating conditions (e.g., the target pressure value and detected pressure feedback value may differ under different operating conditions, leading to different pressure states).

[0088] Furthermore, refer to Figure 2 In a feasible embodiment, step S20 further includes steps S21 to S22:

[0089] Step S21: When the pressure state is in the pressure holding state, the pressure ratio parameter is increased according to the first preset pressure holding coefficient to obtain the target pressure ratio parameter;

[0090] Step S22: Based on the first preset pressure holding coefficient, increase the pressure integral parameter to obtain the target pressure integral parameter.

[0091] It should be noted that when the pressure is in the holding pressure state, it means that the pressure feedback value is close to the system target pressure value. If the pressure feedback value is to be kept near the system target pressure value, and the absolute value of the pressure deviation rate corresponding to the pressure feedback value is less than or equal to the preset pressure stability parameter, then the pressure loop parameter needs to be increased to control the electro-hydraulic servo system to output sufficient pressure, thereby avoiding pressure fluctuations in the electro-hydraulic servo system.

[0092] The pressure loop parameters are preset. These parameters refer to the control parameters of the pressure loop in the electro-hydraulic servo system when it is in a non-pressure-holding state. The pressure loop parameters include proportional and integral pressure parameters. The proportional pressure parameter is the proportional gain in the pressure loop PID controller. A high proportional pressure parameter can accelerate the response speed of the electro-hydraulic servo system, but an excessively high proportional pressure parameter may lead to system overshoot or oscillation. The integral pressure parameter is the integral gain in the pressure loop PID controller, which can eliminate steady-state errors in the electro-hydraulic servo system and improve its stability.

[0093] Both the target pressure proportional parameter and the target pressure integral parameter are control parameters of the pressure loop in the electro-hydraulic servo system when it is in the pressure holding state. When the pressure is holding, the target pressure integral parameter is greater than the pressure integral parameter, and the target pressure proportional parameter is greater than the pressure proportional parameter. The first preset pressure holding coefficient is used to increase the pressure loop parameters.

[0094] For example, when the pressure state is a pressure holding state, the product of the first preset pressure holding coefficient and the pressure proportional parameter is calculated to obtain the first pressure value; the sum of the first pressure value and the pressure proportional parameter is calculated to obtain the target pressure proportional parameter; the product of the first preset pressure holding coefficient and the pressure integral parameter is calculated to obtain the second pressure value; the sum of the second pressure value and the pressure integral parameter is calculated to obtain the target pressure integral parameter.

[0095] In one feasible embodiment, step S20 further includes step S23:

[0096] Step S23: When the pressure state is not a pressure holding state, the pressure proportional parameter is used as the target pressure proportional parameter, and the pressure integral parameter is used as the target pressure integral parameter.

[0097] It should be noted that when the pressure is not in a pressure-holding state, it means that the electro-hydraulic servo system does not need too much pressure at present. In order to avoid pressure fluctuations in the electro-hydraulic servo system, the pressure proportional parameter can be used as the target pressure proportional parameter, and the pressure integral parameter can be used as the target pressure integral parameter.

[0098] As an example, when the pressure condition is not a pressure holding condition, the target pressure proportional parameter is the pressure proportional parameter, and the target pressure integral parameter is the pressure integral parameter.

[0099] As another example, the calculation formula for the target pressure proportional parameter can be referred to:

[0100] Kp_P = Kp_P0 + Kp_P0 * Pflag * Kp1

[0101] Wherein, Kp_P is the target pressure proportional parameter, Kp_P0 is the pressure proportional parameter, Kp1 is the first preset pressure holding coefficient, and Pflag is the status indicator corresponding to the pressure state. When the pressure state is in the pressure holding state, Pflag is the pressure holding indicator 1; when the pressure state is in the non-pressure holding state, Pflag is the non-pressure holding indicator 0. When Pflag is the non-pressure holding indicator 0, the target pressure proportional parameter is equal to the pressure proportional parameter; when Pflag is the pressure holding indicator 1, the target pressure proportional parameter is the product of the pressure proportional parameter, the pressure holding indicator, and the first preset pressure holding coefficient, plus the sum of this product and the pressure proportional parameter.

[0102] As another example, the formula for calculating the integral parameter of the target pressure can be referred to:

[0103] Ki_P = Ki_P0 + Ki_P0 * Pflag * Kp1

[0104] Where Ki_P is the target pressure integral parameter, Ki_P0 is the pressure integral parameter, Kp1 is the first preset pressure holding coefficient, and Pflag is the status flag corresponding to the pressure state. When the pressure state is in the pressure holding state, Pflag is the pressure holding flag 1; when the pressure state is in the non-pressure holding state, Pflag is the non-pressure holding flag 0. When Pflag is the non-pressure holding flag 0, the target pressure integral parameter is equal to the pressure integral parameter; when Pflag is the pressure holding flag 1, the target pressure integral parameter is the product of the pressure integral parameter, the pressure holding flag, and the first preset pressure holding coefficient, plus the sum of this product and the pressure integral parameter.

[0105] This embodiment determines the target pressure parameters corresponding to the non-pressure holding state and the pressure holding state, thereby helping to avoid pressure fluctuations in the electro-hydraulic servo system. When the electro-hydraulic servo system requires more pressure, this embodiment increases the pressure proportional parameter and the pressure integral parameter to meet the needs of the electro-hydraulic servo system. When more pressure is not required, the operation of the electro-hydraulic servo system can still be controlled based on the pressure proportional parameter and the pressure integral parameter without increasing the pressure proportional parameter and the pressure integral parameter, thereby helping to avoid pressure oscillations.

[0106] In one feasible embodiment, step S30 further includes steps S31 to S32:

[0107] Step S31: When the pressure state is a pressure holding state, the target speed ratio parameter is obtained by increasing the speed ratio parameter according to the second preset pressure holding coefficient.

[0108] Step S32: Based on the second preset pressure holding coefficient, increase the speed integral parameter to obtain the target speed integral parameter.

[0109] It should be noted that when the load on the electro-hydraulic servo system changes, the pressure state of the system may also change, for example, it may transition from a pressure-holding state to a non-pressure-holding state. In an electro-hydraulic servo system, higher pressure means that the system needs to drive a larger load or achieve a faster action response.

[0110] When the pressure state changes, the speed loop parameters also need to be adjusted accordingly. For example, when the pressure state is in the holding pressure state, it means that the pressure feedback value is close to the system target pressure value. The electro-hydraulic servo system needs more pressure, and the speed loop parameters need to be increased accordingly to control the electro-hydraulic servo system to output sufficient speed so that the output speed of the electro-hydraulic servo system can match the corresponding pressure feedback value, thereby avoiding the speed oscillation problem of the electro-hydraulic servo system.

[0111] The speed loop parameters are preset. Speed ​​loop parameters refer to the control parameters of the speed loop in the electro-hydraulic servo system when it is in a non-pressure-holding state. Speed ​​loop parameters include proportional speed parameters and integral speed parameters. The proportional speed parameter is the proportional gain in the speed loop PID controller. The proportional speed parameter determines the response speed of the electro-hydraulic servo system to speed errors; the larger the proportional speed parameter, the faster the response speed. The integral speed parameter is the integral gain in the speed loop PID controller.

[0112] Both the target speed proportional parameter and the target speed integral parameter are control parameters of the speed loop in the electro-hydraulic servo system under pressure-holding conditions. When the pressure is maintained, the target speed integral parameter is greater than the speed integral parameter, and the target speed proportional parameter is greater than the speed proportional parameter. The second preset pressure-holding coefficient is used to increase the speed loop parameters.

[0113] For example, when the pressure state is a pressure holding state, the product of the second preset pressure holding coefficient and the speed proportional parameter is calculated to obtain the first speed value. The sum of the first speed value and the speed proportional parameter is calculated to obtain the target speed proportional parameter. The product of the first preset pressure holding coefficient and the speed integral parameter is calculated to obtain the second speed value. The sum of the second speed value and the speed integral parameter is calculated to obtain the target speed integral parameter.

[0114] In one feasible embodiment, step S30 further includes step S33:

[0115] Step S33: When the pressure state is not a pressure holding state, determine the target speed proportional parameter as a speed proportional parameter and determine the target speed integral parameter as a speed integral parameter.

[0116] It should be noted that when the pressure is not in a pressure-holding state, it means that the electro-hydraulic servo system does not need too much pressure at present. In order to avoid speed oscillation in the electro-hydraulic servo system, the speed proportional parameter can be used as the target speed proportional parameter, and the speed integral parameter can be used as the target speed integral parameter.

[0117] As an example, when the pressure state is not a pressure-holding state, the target velocity proportional parameter is the velocity proportional parameter, and the target velocity integral parameter is the velocity integral parameter.

[0118] As another example, the formula for calculating the target velocity ratio parameter can be referenced:

[0119] Kp_spd=Kp_spd0+Kp_spd0*Pflag*Kp2

[0120] Wherein, Kp_spd is the target speed proportional parameter, Kp_spd0 is the speed proportional parameter, Kp2 is the second preset pressure holding coefficient, and Pflag is the status indicator corresponding to the pressure state. When the pressure state is in the pressure holding state, Pflag is the pressure holding indicator 1; when the pressure state is in the non-pressure holding state, Pflag is the non-pressure holding indicator 0. When Pflag is the non-pressure holding indicator 0, the target speed proportional parameter is equal to the speed proportional parameter; when Pflag is the pressure holding indicator 1, the target speed proportional parameter is the product of the speed proportional parameter, the pressure holding indicator, and the second preset pressure holding coefficient, plus the sum of this product and the speed proportional parameter. The first preset pressure holding coefficient and the second preset pressure holding coefficient can be the same or different.

[0121] As another example, the formula for calculating the integral parameter of the target velocity can be given:

[0122] Ki_spd=Ki_spd0+Ki_spd0*Pflag*Kp2

[0123] Wherein, Ki_spd is the target speed integral parameter, Ki_spd0 is the speed integral parameter. When Pflag is a non-pressure holding flag 0, the target speed integral parameter is equal to the speed integral parameter. When Pflag is a pressure holding flag 1, the target speed integral parameter is the product of the speed integral parameter, the pressure holding flag and the second preset pressure holding coefficient, and the sum of this product and the speed integral parameter.

[0124] The first and second preset pressure holding coefficients belong to the preset pressure holding range, which is 0 to 2.

[0125] It should be noted that the preset pressure holding range can be obtained by debugging the electro-hydraulic servo system under actual working conditions. The preset pressure holding range is from 0 to 2. The first and second preset pressure holding coefficients are within the preset pressure holding range. This helps to avoid sudden increases in pressure loop parameters and speed loop parameters when increasing them, thereby preventing instability of the electro-hydraulic servo system. The first and second preset pressure holding coefficients can be determined within the preset pressure holding range based on actual conditions.

[0126] This embodiment adjusts the speed loop parameters to facilitate the provision of higher speeds when the electro-hydraulic servo system requires them. Conversely, when higher speeds are not needed, the system remains stable by controlling the electro-hydraulic servo system based on the speed loop parameters. Therefore, by adjusting the pressure loop and speed loop parameters in response to pressure changes, this invention enables the electro-hydraulic servo system to adapt to pressure variations, thus improving its stability.

[0127] To better understand this embodiment, refer to Figure 3 The process for calculating the target pressure loop parameters and the target velocity loop parameters in this embodiment is briefly described, and the process includes X10 to X50:

[0128] X10: Obtain pressure feedback value from the pressure sensor in the electro-hydraulic servo system; X20: Calculate the pressure error based on the pressure feedback value and the system target pressure value; X30: Calculate the pressure deviation rate based on the pressure error and the system target pressure value; X40: Compare the pressure deviation rate with the preset pressure stability parameter to obtain the pressure state; X50: Calculate the target speed loop parameter based on the pressure state and the speed loop parameter.

[0129] Refer to Figure 4A brief description of the structure of the electro-hydraulic servo system is as follows: The electro-hydraulic servo system may include a judgment and switching module, a pressure loop, a speed loop, a current loop, a PWM (Pulse Width Modulation) modulation algorithm, a PWM inverter, and a motor M. The switching module includes a state judgment unit, a pressure loop parameter adjustment unit, and a speed loop parameter adjustment unit. The state judgment unit can acquire pressure commands and pressure feedback values, and determine the system target pressure value from the pressure commands. The state judgment unit can judge the pressure state based on the system target pressure value and pressure feedback value. The pressure loop parameter adjustment unit adjusts the pressure loop parameters based on the pressure state, and outputs the target pressure proportional parameter Kp_P and the target pressure integral parameter Ki_P to the pressure loop. The speed loop parameter adjustment unit adjusts the speed loop parameters based on the pressure state, and outputs the target speed proportional parameter Kp_spd and the target speed integral parameter Ki_spd to the speed loop. The PID controller of the pressure loop outputs a speed command to the speed loop based on the pressure command, pressure feedback, target pressure proportional parameter, and target pressure integral parameter. The PID controller of the speed loop receives the speed command, the target speed proportional parameter, and the target speed integral parameter, and outputs a current command to the current loop. After receiving the current command, the current loop controls the motor operation through a PWM modulation algorithm and a PWM inverter. Specifically, the current loop can collect the current output by the motor, compare it with the current indicated in the current command, calculate the current error, and generate a PWM signal based on the current error through a PWM modulation algorithm. The PWM inverter receives the PWM signal and converts it into a signal to drive the motor.

[0130] It should be noted that the above specific embodiments are only used to understand the present invention and do not constitute a limitation on the control method of the electro-hydraulic servo system of the present invention. Any simple modifications based on this technical concept are within the protection scope of the present invention.

[0131] This invention also provides a control device for an electro-hydraulic servo system, please refer to... Figure 5 The control device 50 of the electro-hydraulic servo system includes:

[0132] The acquisition module 10 is used to acquire the pressure feedback value and the target pressure value of the electro-hydraulic servo system, and determine the pressure state of the electro-hydraulic servo system based on the pressure feedback value and the target pressure value.

[0133] The first determining module 20 is used to adjust the pressure loop parameters of the electro-hydraulic servo system according to the pressure state to obtain the target pressure loop parameters;

[0134] The second determining module 30 is used to adjust the speed loop parameters of the electro-hydraulic servo system according to the pressure state to obtain the target speed loop parameters;

[0135] The control module 40 is used to control the operation of the electro-hydraulic servo system based on the target pressure loop parameters and the target speed loop parameters.

[0136] The control device 50 for the electro-hydraulic servo system provided by the present invention employs the control method for the electro-hydraulic servo system in the above embodiments, and can solve the technical problem of instability in the electro-hydraulic servo system. Compared with the prior art, the beneficial effects of the control device 50 for the electro-hydraulic servo system provided by the embodiments of the present invention are the same as the beneficial effects of the control method for the electro-hydraulic servo system provided in the above embodiments, and other technical features in the control device 50 for the electro-hydraulic servo system are the same as the features disclosed in the methods of the above embodiments, and will not be repeated here.

[0137] This invention provides an electro-hydraulic servo system, including a controller and a motor, wherein the controller is used to implement the control method of the electro-hydraulic servo system as described above.

[0138] The following is for reference. Figure 6 It shows a schematic diagram of the structure of a control device suitable for implementing the electro-hydraulic servo system of the embodiments of the present disclosure. Figure 6 The structure of the control device for the electro-hydraulic servo system shown is merely an example and should not impose any limitation on the functionality and scope of use of the embodiments disclosed herein.

[0139] like Figure 6 As shown, the control device of the electro-hydraulic servo system may include a processor 101, such as a CPU, a communication bus 102, a user interface 103, a network interface 104, and a memory 105. The communication bus 102 is used to enable communication between these components. The user interface 103 may include a display screen or an input unit such as a keyboard; optionally, the user interface 103 may also include a standard wired interface or a wireless interface. The network interface 104 may optionally include a standard wired interface or a wireless interface (such as a Wi-Fi interface). The memory 105 may be a high-speed RAM or a stable, non-volatile memory, such as a disk drive. Optionally, the memory 105 may also be a storage device independent of the aforementioned processor 101.

[0140] Those skilled in the art will understand that Figure 6 The control device structure of the electro-hydraulic servo system shown does not constitute a limitation on the control device of the electro-hydraulic servo system. It may include more or fewer components than shown, or combine certain components, or have different component arrangements.

[0141] like Figure 6As shown, the memory 105, which serves as a computer storage medium, may include an operating system, a network communication module, a user interface module, and a control program for an electro-hydraulic servo system.

[0142] exist Figure 6 In the control device of the electro-hydraulic servo system shown, the network interface 104 is mainly used to connect to the back-end server and communicate data with the back-end server; the user interface 103 is mainly used to connect to the client and communicate data with the client; and the processor 101 can be used to call the control program of the electro-hydraulic servo system stored in the memory 105 to execute the steps of the control method of the electro-hydraulic servo system.

[0143] The electro-hydraulic servo system provided by this invention, employing the control method of the electro-hydraulic servo system in the above embodiments, can solve the technical problem of instability in electro-hydraulic servo systems. Compared with the prior art, the beneficial effects of the electro-hydraulic servo system provided by this invention are the same as the beneficial effects of the control method of the electro-hydraulic servo system provided in the above embodiments, and other technical features of this electro-hydraulic servo system are the same as those disclosed in the method of the previous embodiment, and will not be repeated here.

[0144] It should be understood that various parts of this disclosure can be implemented using hardware, software, firmware, or a combination thereof. In the description of the above embodiments, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

[0145] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

[0146] This invention provides a computer-readable storage medium including computer-readable program instructions stored thereon, which are used to execute the control method of the electro-hydraulic servo system in the above embodiment 1.

[0147] The computer-readable storage medium provided in this embodiment of the invention may be, for example, a USB flash drive, but is not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device, or any combination thereof. More specific examples of a computer-readable storage medium may include, but are not limited to, electrical connections including one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof. In this embodiment, the computer-readable storage medium may be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, system, or device. The program code contained on the computer-readable storage medium may be transmitted using any suitable medium, including but not limited to: wires, optical cables, RF (Radio Frequency), etc., or any suitable combination thereof.

[0148] The aforementioned computer-readable storage medium may be included in the control device of the electro-hydraulic servo system; or it may exist independently and not be assembled into the control device of the electro-hydraulic servo system.

[0149] The aforementioned computer-readable storage medium carries one or more programs. When these programs are executed by the control device of the electro-hydraulic servo system, the control device of the electro-hydraulic servo system causes the following actions: acquiring the pressure feedback value and the target pressure value of the electro-hydraulic servo system; determining the pressure state of the electro-hydraulic servo system based on the pressure feedback value and the target pressure value; adjusting the pressure loop parameters of the electro-hydraulic servo system to obtain target pressure loop parameters based on the pressure state; adjusting the speed loop parameters of the electro-hydraulic servo system to obtain target speed loop parameters based on the pressure state; and controlling the operation of the electro-hydraulic servo system based on the target pressure loop parameters and the target speed loop parameters.

[0150] Computer program code for performing the operations of this disclosure can be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, and C++, and conventional procedural programming languages ​​such as the "C" language or similar programming languages. The program code can be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving remote computers, the remote computer can be connected to the user's computer via any type of network—including a local area network (LAN) or a wide area network (WAN)—or can be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0151] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions.

[0152] The modules described in the embodiments of this disclosure can be implemented in software or hardware. The names of the modules do not necessarily limit the functionality of the unit itself.

[0153] The readable storage medium provided by this invention is a computer-readable storage medium that stores computer-readable program instructions for executing the control method of the electro-hydraulic servo system described above, thereby solving the technical problem of instability in the electro-hydraulic servo system. Compared with the prior art, the beneficial effects of the computer-readable storage medium provided in the embodiments of this invention are the same as the beneficial effects of the control method of the electro-hydraulic servo system provided in the above embodiments, and will not be repeated here.

[0154] This invention also provides a computer program product, including a computer program that, when executed by a processor, implements the steps of the control method for the electro-hydraulic servo system as described above.

[0155] The computer program product provided by this invention can solve the technical problem of instability in electro-hydraulic servo systems. Compared with the prior art, the beneficial effects of the computer program product provided in the embodiments of this invention are the same as the beneficial effects of the control method for the electro-hydraulic servo system provided in the above embodiments, and will not be repeated here.

[0156] The above are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent scope of the present invention.

Claims

1. A control method for an electro-hydraulic servo system, characterized in that, The control method of the electro-hydraulic servo system includes: Obtain the pressure feedback value and the target pressure value of the electro-hydraulic servo system, and determine the pressure state of the electro-hydraulic servo system based on the pressure feedback value and the target pressure value. Based on the pressure state, the pressure loop parameters of the electro-hydraulic servo system are adjusted to obtain the target pressure loop parameters; Based on the pressure state, the speed loop parameters of the electro-hydraulic servo system are adjusted to obtain the target speed loop parameters; The electro-hydraulic servo system is controlled based on the target pressure loop parameters and the target speed loop parameters.

2. The method as described in claim 1, characterized in that, The step of determining the pressure state of the electro-hydraulic servo system based on the pressure feedback value and the system target pressure value includes: Determine the pressure error between the pressure feedback value and the system target pressure value; The pressure deviation rate is obtained by calculating the ratio of the pressure error to the system target pressure value. The pressure state is determined based on the pressure deviation rate and the preset pressure stability parameters.

3. The method as described in claim 2, characterized in that, The step of determining the pressure state based on the pressure deviation rate and the preset pressure stability parameters includes: When the absolute value of the pressure deviation rate is less than or equal to the preset pressure stability parameter, the pressure state is determined to be a pressure holding state. When the absolute value of the pressure deviation rate is greater than the preset pressure stability parameter, the pressure state is determined to be a non-pressure holding state.

4. The method as described in claim 1, characterized in that, The pressure loop parameters include pressure proportional parameters and pressure integral parameters, and the target pressure loop parameters include target pressure proportional parameters and target pressure integral parameters; The step of adjusting the pressure loop parameters of the electro-hydraulic servo system according to the pressure state to obtain the target pressure loop parameters includes: When the pressure state is a pressure holding state, the target pressure ratio parameter is obtained by increasing the pressure ratio parameter according to the first preset pressure holding coefficient. The target pressure integral parameter is obtained by increasing the pressure integral parameter based on the first preset pressure holding coefficient.

5. The method as described in claim 1, characterized in that, The pressure loop parameters include pressure proportional parameters and pressure integral parameters, and the target pressure loop parameters include target pressure proportional parameters and target pressure integral parameters; The step of adjusting the pressure loop parameters of the electro-hydraulic servo system according to the pressure state to obtain the target pressure loop parameters includes: When the pressure state is a non-pressure-holding state, the pressure proportional parameter is used as the target pressure proportional parameter, and the pressure integral parameter is used as the target pressure integral parameter.

6. The method as described in claim 1, characterized in that, The velocity loop parameters include velocity proportional parameters and velocity integral parameters, and the target velocity loop parameters include target velocity proportional parameters and target velocity integral parameters; The step of adjusting the speed loop parameters of the electro-hydraulic servo system according to the pressure state to obtain the target speed loop parameters includes: When the pressure state is a pressure holding state, the speed ratio parameter is increased according to the second preset pressure holding coefficient to obtain the target speed ratio parameter; Based on the second preset pressure holding coefficient, the speed integral parameter is increased to obtain the target speed integral parameter.

7. The method as described in claim 1, characterized in that, The velocity loop parameters include velocity proportional parameters and velocity integral parameters, and the target velocity loop parameters include target velocity proportional parameters and target velocity integral parameters; The step of adjusting the speed loop parameters of the electro-hydraulic servo system according to the pressure state to obtain the target speed loop parameters includes: When the pressure state is a non-pressure-holding state, the speed proportional parameter is used as the target speed proportional parameter, and the speed integral parameter is used as the target speed integral parameter.

8. A control device for an electro-hydraulic servo system, characterized in that, The device includes: The acquisition module is used to acquire the pressure feedback value and the target pressure value of the electro-hydraulic servo system, and determine the pressure state of the electro-hydraulic servo system based on the pressure feedback value and the target pressure value. The first determining module is used to adjust the pressure loop parameters of the electro-hydraulic servo system according to the pressure state to obtain the target pressure loop parameters; The second determining module is used to adjust the speed loop parameters of the electro-hydraulic servo system according to the pressure state to obtain the target speed loop parameters; The control module is used to control the operation of the electro-hydraulic servo system based on the target pressure loop parameters and the target speed loop parameters.

9. An electro-hydraulic servo system, characterized in that, It includes a controller and a motor, the controller being used to implement the steps of the control method for the electro-hydraulic servo system as described in any one of claims 1-7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a control program for an electro-hydraulic servo system that can run on a processor. The control program for the electro-hydraulic servo system is invoked by the processor to implement the steps of the control method for the electro-hydraulic servo system according to any one of claims 1-7.

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