Current interpolation system and method for electro-hydraulic proportional control system

Abstract

The present invention discloses a current interpolation system and method for an electro-hydraulic proportional control system. The current interpolation system includes a detection unit, an operation unit, and an execution unit. The detection unit collects handle data and workload data, and its output is connected to the input of the operation unit. The operation unit calculates a number of handle opening values ​​based on the handle data output by the detection unit, and also adjusts the width of the original hysteresis region based on the workload data output by the detection unit to generate a new hysteresis region. Finally, based on the handle opening value and the new hysteresis region, a control current line of the actuator to be controlled is calculated using a continuous interpolation method. The execution unit is connected to the operation unit, receives the control current line of the actuator to be controlled, converts it into a control instruction, and sends it to the corresponding actuator. Based on the full consideration of the hysteresis interval, the present invention overcomes the operational hysteresis caused by the inherent hysteresis of the hydraulic system through a proportional interpolation method, thereby improving operational efficiency.

Description

Technical Field

[0001] The present invention belongs to the technical field of engineering vehicles, and in particular relates to a current interpolation system and method for an electro-hydraulic proportional control system. Background Art

[0002] Comprehensively analyzing the implementation methods of control systems in the wheeled crane industry at home and abroad, there are mainly two types: hydraulic proportional control systems and electro-hydraulic proportional control systems. The hydraulic proportional control system has a large power-to-mass ratio, a high speed regulation ratio, and smooth energy transmission. It can ensure the smooth and reliable operation of the actuators of engineering machinery during operation and is a key system for realizing crane motion control. In addition, the hydraulic proportional control system is also characterized by low cost. It currently occupies a dominant position in the product line of small and medium-sized cranes under 80 tons in the domestic and foreign crane markets. Since the 1990s, electronic technology, computer technology and hydraulic proportional control systems have been effectively combined. The information collection, processing and storage capabilities of cranes have been effectively improved, and hydraulic proportional control systems have gradually evolved towards electro-hydraulic proportional control. Relying on its unique ability to implement complex control strategy functions, the electro-hydraulic proportional system is more conducive to improving the refined control capabilities and intelligent level of crane motion.

[0003] Compared with the traditional hydraulic proportional control system, the control chain of the electro-hydraulic proportional control system is longer, usually including the electric control handle-programmable controller-solenoid valve-pilot valve-pilot oil-main valve-cylinder (motor)-actuator. Therefore, the hysteresis effect of the electro-hydraulic proportional control system is greater, which is usually manifested as the actuator's action having poor follow-up performance to the handle and low controllability, which is very unfavorable for the crane's refined lifting operations.

[0004] Chinese invention patent application CN113378311A proposes a method, device, excavator, and processor for compensating for hysteresis in an excavator proportional valve. This approach reduces hysteresis by superimposing a vibration signal on the proportional valve's PWM signal. While this solution can reduce friction between the proportional solenoid's armature and bushing, it offers limited improvement in hysteresis caused primarily by valve core friction and static fluid dynamics.

[0005] The Chinese invention patent application, publication number CN113325886A, proposes a valve hysteresis compensation method, device, electronic device, and storage medium. These methods determine a target pressure based on an input current; a predicted pressure based on the input current and a mechanical fluid model; a first control current based on the target pressure and the predicted pressure; a second control current based on the input current and a circuit model; and a compensated current based on the first and second control currents, which is then input into a proportional valve for hysteresis compensation. This solution introduces a new method to overcome proportional valve hysteresis, but the control effect is significantly affected by model accuracy and requires high computational performance from the vehicle body control unit, making it difficult to implement in engineering.

[0006] In the Chinese invention patent application with publication number CN110332257A, a clutch pressure hysteresis control optimization method and device are proposed. During the clutch engagement and disengagement process, the preset pressure curve of the clutch output under the control of the first control current is first obtained, and the pressure curve is divided into different state stages according to the working process and the target action. The different state stages of the preset reference pressure curve are provided with corresponding second control currents. According to the matching of the current pressure value and the current pressure change trend with the preset reference pressure curve, the current state stage is judged, and the second control current corresponding to the current state stage is used to control the clutch action process, compensate for the pressure hysteresis on the clutch hydraulic element, improve the pressure control accuracy, and improve the shifting quality. This scheme provides a hysteresis compensation method in the clutch working scenario, obtains the predicted pressure curve based on the first control current, and then obtains the second target control current, which is quite different from the speed regulation method of the crane main valve operating condition.

[0007] Chinese invention patent application CN113819269A proposes a proportional directional control valve that eliminates main valve hysteresis. This design aims to eliminate friction-induced hysteresis in a hydraulic servo system, addressing the hysteresis and low control accuracy issues caused by friction between the valve core and valve body. This solution reduces hysteresis by alleviating friction between the valve core and valve body, but it places high demands on the production equipment and processing technology for the valve body and valve core, resulting in increased costs.

[0008] The Chinese utility model patent application, publication number CN 207161411, proposes a digital, direct-acting proportional pressure relief valve with closed-loop position control. This valve integrates a proportional solenoid with a displacement sensor and a digital integrated amplifier for closed-loop position control. This valve's regulated pressure is proportional to the input signal, resulting in more precise hydraulic system pressure, reduced hysteresis, increased sensitivity, and reduced sensitivity to interference factors such as oil temperature and system overflow. However, this solution, with its built-in displacement sensor and digital integrated amplifier for closed-loop position control, results in high component costs, making it unsuitable for crane applications. Summary of the Invention

[0009] In response to the above problems, the present invention proposes a current interpolation system and method for an electro-hydraulic proportional control system. On the basis of fully considering the hysteresis interval, the proportional interpolation method is used to overcome the operational delay caused by the inherent hysteresis of the hydraulic system and improve the operating efficiency.

[0010] In order to achieve the above technical objectives and the above technical effects, the present invention is implemented through the following technical solutions:

[0011] In a first aspect, the present invention provides a current interpolation system for an electro-hydraulic proportional control system, comprising a detection unit, a calculation unit, and an execution unit;

[0012] The detection unit collects handle data and workload data, and its output end is connected to the input end of the calculation unit;

[0013] The computing unit calculates a plurality of handle opening values ​​based on the handle data output by the detection unit, and further adjusts the width of the original hysteresis band based on the workload data output by the detection unit to generate a new hysteresis band. Finally, based on the handle opening values ​​and the new hysteresis band, a control current line of the actuator to be controlled is calculated using a continuous interpolation method.

[0014] The execution unit is connected to the operation unit, receives the control current line of the actuator to be controlled, converts it into a control instruction, and then sends it to the corresponding actuator.

[0015] Optionally, the current interpolation system further includes a human interface unit, which is connected to the operation unit to perform parameter settings on the operation unit.

[0016] Optionally, the human interface unit is further connected to the detection unit and the execution unit, and is used to display the collected handle data, workload data and control current lines of each actuator to be controlled.

[0017] Optionally, the detection unit includes a user manipulation action detection module and a workload state detection module that are independent of each other;

[0018] The user manipulation motion detection module collects the motion direction, motion position and motion acceleration of the handle;

[0019] The working load state detection module collects the pressure load state of the crane and the temperature load state of the working medium in the hydraulic system of the crane.

[0020] Optionally, the operation unit includes a user manipulation intention recognition module and a current interpolation data calculation module;

[0021] The user manipulation intention recognition module removes abnormal data in the received handle data and smoothes step data in the handle data to obtain the handle's movement direction, movement position, and movement acceleration, and calculates a number of handle opening values ​​based on the handle's movement direction, movement position, and movement acceleration;

[0022] The current interpolation data calculation module is connected to the workload state detection module and the user manipulation intention recognition module, respectively. Based on the crane pressure load state output by the workload state detection module and the temperature load state of the working medium in the crane hydraulic system, the width of the original hysteresis loop region pre-stored in the current interpolation data calculation module is adjusted to generate a new hysteresis loop region. Based on several handle opening values ​​output by the user manipulation intention recognition module and the new hysteresis loop region, a continuous interpolation method is used to calculate the control current line of the actuator to be controlled.

[0023] Optionally, the control current line of the actuator to be controlled is specifically:

[0024] When the user operates the handle in a return operation mode with a maximum stroke, the control current line includes an outbound line and a return line that are parallel to each other, and the two endpoints of the outbound line and the return line correspond to the maximum handle opening value and the minimum handle opening value in the new hysteresis band area, respectively;

[0025] When the user operates the handle in a return operation mode at the intermediate position, the control current line includes an intersecting outbound line and a return line, the intersection of the outbound line and the return line is located between the maximum handle opening value and the minimum handle opening value on the new hysteresis band area, and the other ends of the outbound line and the return line both correspond to the minimum handle opening value on the new hysteresis band area;

[0026] When the user operates the handle in a Z-shaped return operation mode, the control current line includes multiple intersecting outbound lines and return lines, one end of the first outbound line and the last return line corresponds to the minimum handle opening value on the new hysteresis loop area, and the other ends are both located between the maximum and minimum handle opening values ​​on the new hysteresis loop area, and both ends of the remaining outbound lines and return lines are both located between the maximum and minimum handle opening values ​​on the new hysteresis loop area.

[0027] In a second aspect, the present invention provides a current interpolation method for an electro-hydraulic proportional control system, comprising:

[0028] collecting handle data and workload data using a detection unit, and sending the handle data and workload data to a calculation unit;

[0029] A plurality of handle opening values ​​are calculated by a computing unit based on handle data output by a detection unit, a width of an original hysteresis band is adjusted based on workload data output by the detection unit to generate a new hysteresis band, and a control current line of the actuator to be controlled is calculated using a continuous interpolation method based on the handle opening value and the new hysteresis band;

[0030] The execution unit receives the control current line of the actuator to be controlled output by the operation unit, converts it into a control instruction, and then sends it to the corresponding actuator.

[0031] Optionally, the current interpolation method further includes:

[0032] The human interface unit is used to set parameters of the operation unit, and the human interface unit is used to receive handle data, workload data and control current lines of each actuator to be controlled from the detection unit and the execution unit, and display them.

[0033] Optionally, the detection unit includes a user manipulation action detection module and a workload state detection module that are independent of each other;

[0034] The user manipulation motion detection module collects the motion direction, motion position and motion acceleration of the handle;

[0035] The working load state detection module collects the pressure load state of the crane and the temperature load state of the working medium in the hydraulic system of the crane.

[0036] Optionally, the operation unit includes a user manipulation intention recognition module and a current interpolation data calculation module;

[0037] The user manipulation intention recognition module removes abnormal data in the received handle data and smoothes step data in the handle data to obtain the handle's movement direction, movement position, and movement acceleration, and calculates a number of handle opening values ​​based on the handle's movement direction, movement position, and movement acceleration;

[0038] The current interpolation data calculation module is connected to the workload state detection module and the user manipulation intention recognition module, respectively. Based on the crane pressure load state output by the workload state detection module and the temperature load state of the working medium in the crane hydraulic system, the width of the original hysteresis loop region pre-stored in the current interpolation data calculation module is adjusted to generate a new hysteresis loop region. Based on several handle opening values ​​output by the user manipulation intention recognition module and the new hysteresis loop region, a continuous interpolation method is used to calculate the control current line of the actuator to be controlled.

[0039] Optionally, the control current line of the actuator to be controlled is specifically:

[0040] When the user operates the handle in a return operation mode with a maximum stroke, the control current line includes an outbound line and a return line that are parallel to each other, and the two endpoints of the outbound line and the return line correspond to the maximum handle opening value and the minimum handle opening value in the new hysteresis band area, respectively;

[0041] When the user operates the handle in a return operation mode at the intermediate position, the control current line includes an intersecting outbound line and a return line, the intersection of the outbound line and the return line is located between the maximum handle opening value and the minimum handle opening value on the new hysteresis band area, and the other ends of the outbound line and the return line both correspond to the minimum handle opening value on the new hysteresis band area;

[0042] When the user operates the handle in a Z-shaped return operation mode, the control current line includes multiple intersecting outbound lines and return lines, one end of the first outbound line and the last return line corresponds to the minimum handle opening value on the new hysteresis loop area, and the other ends are both located between the maximum and minimum handle opening values ​​on the new hysteresis loop area, and both ends of the remaining outbound lines and return lines are both located between the maximum and minimum handle opening values ​​on the new hysteresis loop area.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] The present invention, on the basis of fully considering the hysteresis area, detects information such as the movement direction, movement position and movement acceleration of the handle in real time, obtains several handle opening values, and performs current interpolation between the minimum outward stroke, the middle of the outward stroke, the maximum outward stroke, the maximum return stroke, the middle of the return stroke and the minimum return stroke in the new hysteresis area. It can realize continuous current output under any operation input and continuous compensation of special-shaped hysteresis areas, overcome the operation delay caused by the inherent hysteresis of the hydraulic system, provide users with a good operation experience, and improve work efficiency and basic intelligent capabilities of the product.

[0045] The present invention does not require additional hardware and has lower cost and higher economic value compared to means such as valve core displacement detection and oil pump swash plate position detection.

[0046] The present invention can adjust the performance by using a continuous interpolation method when the performance of the hydraulic component is attenuated, thereby facilitating the operation and maintenance of the main performance of the crane product.

[0047] The present invention can directly install upgraded software on the original vehicle system of the crane, while the hardware remains unchanged, and is more suitable for performance modification of existing products in the market. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below based on specific embodiments and in conjunction with the accompanying drawings, wherein:

[0049] Figure 1 A schematic structural diagram of a current interpolation system for an electro-hydraulic proportional control system according to an embodiment of the present invention;

[0050] Figure 2 This is a schematic diagram of hysteresis area interpolation when the user operates the handle in the return operation mode with maximum stroke;

[0051] Figure 3 This is a schematic diagram of hysteresis area interpolation when the user operates the handle in a return operation at the middle position;

[0052] Figure 4 This is a schematic diagram of hysteresis area interpolation when the user operates the handle in a Z-shaped return operation;

[0053] Figure 5 This is a schematic diagram of the hysteresis region interpolation process when the user operates the handle in a return operation with a maximum stroke;

[0054] Figure 6 Schematic diagram of the hysteresis region interpolation process when the user operates the handle in a middle position return operation mode;

[0055] Figure 7 This is a schematic diagram of the hysteresis area interpolation process when the user operates the handle in a Z-shaped return operation. DETAILED DESCRIPTION

[0056] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the scope of protection of the present invention.

[0057] The application principle of the present invention is described in detail below with reference to the accompanying drawings.

[0058] Example 1

[0059] like Figure 1 As shown, an embodiment of the present invention provides a current interpolation system for an electro-hydraulic proportional control system, including a detection unit, a calculation unit and an execution unit;

[0060] The detection unit collects handle data and workload data, and its output end is connected to the input end of the calculation unit;

[0061] The computing unit calculates a plurality of handle opening values ​​based on the handle data output by the detection unit, and further adjusts the width of the original hysteresis band based on the workload data output by the detection unit to generate a new hysteresis band. Finally, based on the handle opening values ​​and the new hysteresis band, a control current line of the actuator to be controlled is calculated using a continuous interpolation method.

[0062] The execution unit is connected to the operation unit, receives the control current line of the actuator to be controlled, converts it into a control instruction, and then sends it to the corresponding actuator.

[0063] The current interpolation system in the embodiment of the present invention, on the basis of fully considering the hysteresis area, detects the movement direction, movement position and movement acceleration and other information of the handle in real time, obtains several handle opening values, and performs current interpolation between the minimum outward stroke, the middle of the outward stroke, the maximum outward stroke, the maximum return stroke, the middle of the return stroke and the minimum return stroke in the new hysteresis area. It can realize continuous current output under any operation input and continuous compensation of special-shaped hysteresis areas, and can overcome the operation delay caused by the inherent hysteresis of the hydraulic system, provide users with a good operation experience, and improve work efficiency and basic intelligent capabilities of the product.

[0064] In specific applications, the actuators to be controlled may include electro-hydraulic proportional main pumps, electro-hydraulic proportional main valves, chassis electro-hydraulic proportional steering, overflow valves and other electro-hydraulic proportional systems to improve control accuracy and ensure equipment operation safety.

[0065] In a specific implementation of the embodiment of the present invention, Figure 1 As shown, the current interpolation system further includes a human interface unit, which is connected to the arithmetic unit and sets parameters for the arithmetic unit. The human interface unit is also connected to the detection unit and the execution unit, and is used to display the collected handle data, workload data, and the control current lines of each actuator to be controlled. In a specific implementation, the human interface unit includes an operation process status monitoring module and a current interpolation data setting module. The operation process status monitoring module is connected to the detection unit and the execution unit, respectively, and is used to display the collected handle data, workload data, and the control current lines of each actuator to be controlled. The current interpolation data setting module is connected to the arithmetic unit and sets parameters for the arithmetic unit. The parameters include hysteresis data under different pressure load conditions and temperature load conditions. The hysteresis data is stored in a tabular form. The arithmetic unit can generate a raw hysteresis area based on the hysteresis data. The horizontal axis of the raw hysteresis area represents the control current in mA, and the vertical axis represents the handle opening value in %. The current interpolation data setting module is further used to set the minimum outgoing current, the maximum outgoing current, the maximum return current and the minimum return current in the hysteresis band area.

[0066] In a specific implementation of the embodiment of the present invention, Figure 1 As shown, the detection unit includes a user manipulation action detection module and a workload state detection module that are independent of each other;

[0067] The user manipulation motion detection module collects the motion direction, motion position and motion acceleration of the handle;

[0068] The working load state detection module collects the pressure load state of the crane and the temperature load state of the working medium in the hydraulic system of the crane.

[0069] In a specific implementation of the embodiment of the present invention, Figure 1 As shown, the operation unit includes a user control intention recognition module and a current interpolation data calculation module;

[0070] The user manipulation intention recognition module removes abnormal data (such as user operation jitter data) in the received handle data and smoothes the step data in the handle data to obtain the handle's movement direction, movement position and movement acceleration (i.e., the real and effective operation intention, which includes action and stop). Based on the movement direction, movement position and movement acceleration of the handle, the module calculates several handle opening values. The handle opening values ​​can be calculated using existing methods and will not be described in detail in this application.

[0071] The current interpolation data calculation module is connected to the workload state detection module and the user manipulation intention recognition module, respectively. Based on the crane pressure load state and the temperature load state of the working medium in the crane hydraulic system output by the workload state detection module, the width of the original hysteresis region pre-stored in the current interpolation data calculation module is adjusted to generate a new hysteresis region. Based on the handle opening values ​​output by the user manipulation intention recognition module and the new hysteresis region, a control current line for the actuator to be controlled is calculated using a continuous interpolation method. Specifically, the width of the hysteresis region is adjusted based on the temperature load state. Specifically, the lower the temperature load, the larger the hysteresis region width and the larger the hysteresis region area; the higher the temperature, the smaller the hysteresis region width and the smaller the hysteresis region area. The width of the hysteresis region is adjusted based on the pressure load state. Specifically, the higher the pressure load, the larger the hysteresis region width and the larger the hysteresis region area; the lower the pressure load, the smaller the hysteresis region width and the smaller the hysteresis region area. The present invention achieves compensation for the pressure load and temperature load of the crane by adjusting the width of the hysteresis loop region, thereby enhancing the ability of the system (such as an excavator) to adapt to changes in external working conditions.

[0072] like Figure 2 and 5 As shown, when the user operates the handle in the mode of the maximum stroke return operation, the current interpolation data calculation module performs the following process:

[0073] Based on the minimum and maximum handle opening values ​​in the new hysteresis region, the outbound path 1 is generated using the continuous interpolation method.

[0074] If the handle opening value is greater than the maximum handle opening value, a continuous interpolation method is used to generate return path 1 based on the maximum handle opening value and the minimum handle opening value in the new hysteresis region.

[0075] like Figure 3 and 6 As shown, when the user operates the handle in the middle position, the current interpolation data calculation module performs the following process:

[0076] Generate outward path 2 based on the minimum handle opening value on the new hysteresis region and the intermediate value between the maximum handle opening value and the minimum handle opening value on the new hysteresis region;

[0077] If the handle opening value decreases, a return stroke 2 is generated based on the intermediate value between the maximum handle opening value and the minimum handle opening value on the new hysteresis band area and the minimum handle opening value on the new hysteresis band area;

[0078] like Figure 4 and 7 As shown, when the user operates the handle in a zigzag return mode, the current interpolation data calculation module performs the following process:

[0079] Generate outward path 3 based on the minimum handle opening value on the new hysteresis region and the intermediate value 1 between the maximum handle opening value and the minimum handle opening value on the new hysteresis region;

[0080] If the handle opening value decreases, a return stroke 3 is generated based on an intermediate value 1 between the maximum handle opening value and the minimum handle opening value located in the new hysteresis region and based on an intermediate value 2 between the maximum handle opening value and the minimum handle opening value located in the new hysteresis region;

[0081] If the handle opening value is equal to the minimum handle opening value corresponding to the return stroke 3 and the handle opening value increases, then based on the intermediate value 2 between the maximum handle opening value and the minimum handle opening value located in the new hysteresis region and based on the intermediate value 3 between the maximum handle opening value and the minimum handle opening value located in the new hysteresis region, the outward stroke 4 is generated;

[0082] If the handle opening value is greater than the maximum handle opening value corresponding to the forward stroke 4, the forward stroke 3 is generated, and the Z-shaped operation process is completed.

[0083] The above three modes of user operation handles can cover any operation, and finally the control current line of the actuator to be controlled can be obtained, specifically:

[0084] When the user operates the handle in a return operation mode with a maximum stroke, the control current line includes an outbound line and a return line that are parallel to each other, and the two endpoints of the outbound line and the return line correspond to the maximum handle opening value and the minimum handle opening value in the new hysteresis band area, respectively;

[0085] When the user operates the handle in a return operation mode at the intermediate position, the control current line includes an intersecting outbound line and a return line, the intersection of the outbound line and the return line is located between the maximum handle opening value and the minimum handle opening value on the new hysteresis band area, and the other ends of the outbound line and the return line both correspond to the minimum handle opening value on the new hysteresis band area;

[0086] When the user operates the handle in a Z-shaped return operation mode, the control current line includes multiple intersecting outbound lines and return lines, one end of the first outbound line and the last return line corresponds to the minimum handle opening value on the new hysteresis loop area, and the other ends are both located between the maximum and minimum handle opening values ​​on the new hysteresis loop area, and both ends of the remaining outbound lines and return lines are both located between the maximum and minimum handle opening values ​​on the new hysteresis loop area.

[0087] In a specific implementation of an embodiment of the present invention, the number of new hysteresis regions is equal to the number of actuators to be controlled, and the number of control current lines output by the current interpolation data calculation module is also equal to the number of actuators to be controlled; the execution module includes a proportional main valve output execution module and a variable main pump output execution module, both of which are connected to the output end of the current interpolation data calculation module, and generate corresponding control instructions based on the proportional main valve control current line and the variable main pump control current line output by the current interpolation data calculation module, and then send them to the proportional main valve and the variable main pump. In the specific implementation process, the proportional main valve output execution module: converts the proportional valve current of the current interpolation data calculation module into PWM output, drives the proportional valve, and realizes continuous adjustment of the action speed and action direction of the proportional main valve; the variable main pump output execution module: converts the oil pump current of the current interpolation data calculation module into PWM output, drives the oil pump variable mechanism, and realizes continuous adjustment of the action speed of the oil pump variable mechanism.

[0088] Example 2

[0089] The present invention provides a current interpolation method for an electro-hydraulic proportional control system, comprising the following steps:

[0090] (1) using a detection unit to collect handle data and workload data, and sending the handle data and workload data to a calculation unit;

[0091] (2) using the computing unit to calculate a plurality of handle opening values ​​based on the handle data output by the detection unit, and also adjusting the width of the original hysteresis region based on the workload data output by the detection unit to generate a new hysteresis region, and finally calculating the control current line of the actuator to be controlled based on the handle opening value and the new hysteresis region using a continuous interpolation method;

[0092] (3) The execution unit receives the control current line of the actuator to be controlled output by the operation unit, converts it into a control instruction, and sends it to the corresponding actuator.

[0093] The current interpolation method in the embodiment of the present invention, based on full consideration of the hysteresis area, detects information such as the handle's movement direction, movement position, and movement acceleration in real time, obtains several handle opening values, and performs current interpolation between the minimum outward stroke, the middle of the outward stroke, the maximum outward stroke, the maximum return stroke, the middle of the return stroke, and the minimum return stroke in the new hysteresis area. This can achieve continuous current output under any operational input, achieve continuous compensation for irregular hysteresis areas, overcome operational delays caused by the inherent hysteresis of the hydraulic system, provide users with a better operating experience, and improve operational efficiency and the basic intelligent capabilities of the product. In the specific implementation process, the current interpolation method in the embodiment of the present invention can be implemented based on the current interpolation system in Example 1.

[0094] In specific applications, the actuators to be controlled may include electro-hydraulic proportional main pumps, electro-hydraulic proportional main valves, chassis electro-hydraulic proportional steering, overflow valves and other electro-hydraulic proportional systems to improve control accuracy and ensure equipment operation safety.

[0095] In a specific implementation of the embodiment of the present invention, Figure 1 As shown, the current interpolation system also includes a human interface unit, and the current interpolation method further includes: using the human interface unit to set parameters for the arithmetic unit, and using the human interface unit to receive and display handle data, workload data, and control current lines of each actuator to be controlled from the detection unit and the execution unit. Specifically, the human interface unit is connected to the arithmetic unit to set parameters for the arithmetic unit; the human interface unit is connected to the detection unit and the execution unit to display the collected handle data, workload data, and control current lines of each actuator to be controlled. During the specific implementation process, the human interface unit includes an operation process status monitoring module and a current interpolation data setting module; the operation process status monitoring module is respectively connected to the detection unit and the execution unit, and is used to display the collected handle data, work load data and the control current line of each actuator to be controlled; the current interpolation data setting module is connected to the operation unit to set parameters for the operation unit, and the parameters include hysteresis data under different pressure load states and temperature load states. The hysteresis data exists in a table form, and the operation unit can generate an original hysteresis area based on the hysteresis data. The horizontal axis of the original hysteresis area represents the control current in mA, and the vertical axis represents the handle opening value in "%". The current interpolation data setting module is also used to set the minimum outbound current, maximum outbound current, maximum return current and minimum return current of the hysteresis area. The current interpolation method also includes:

[0096] In a specific implementation of the embodiment of the present invention, Figure 1 As shown, the detection unit includes a user manipulation action detection module and a workload state detection module that are independent of each other;

[0097] The user manipulation motion detection module collects the motion direction, motion position and motion acceleration of the handle;

[0098] The working load state detection module collects the pressure load state of the crane and the temperature load state of the working medium in the hydraulic system of the crane.

[0099] In a specific implementation of the embodiment of the present invention, Figure 1 As shown, the operation unit includes a user control intention recognition module and a current interpolation data calculation module;

[0100] The user manipulation intention recognition module removes abnormal data (such as user operation jitter data) in the received handle data and smoothes the step data in the handle data to obtain the handle's movement direction, movement position and movement acceleration (i.e., the real and effective operation intention, which includes action and stop). Based on the movement direction, movement position and movement acceleration of the handle, the module calculates several handle opening values. The handle opening values ​​can be calculated using existing methods and will not be described in detail in this application.

[0101] The current interpolation data calculation module is connected to the workload state detection module and the user manipulation intention recognition module, respectively. Based on the crane pressure load state and the temperature load state of the working medium in the crane hydraulic system output by the workload state detection module, the width of the original hysteresis region pre-stored in the current interpolation data calculation module is adjusted to generate a new hysteresis region. Based on the handle opening values ​​output by the user manipulation intention recognition module and the new hysteresis region, a control current line for the actuator to be controlled is calculated using a continuous interpolation method. Specifically, the width of the hysteresis region is adjusted based on the temperature load state. Specifically, the lower the temperature load, the larger the hysteresis region width and the larger the hysteresis region area; the higher the temperature, the smaller the hysteresis region width and the smaller the hysteresis region area. The width of the hysteresis region is adjusted based on the pressure load state. Specifically, the higher the pressure load, the larger the hysteresis region width and the larger the hysteresis region area; the lower the pressure load, the smaller the hysteresis region width and the smaller the hysteresis region area. The present invention achieves compensation for the pressure load and temperature load of the crane by adjusting the width of the hysteresis loop region, thereby enhancing the ability of the system (such as an excavator) to adapt to changes in external working conditions.

[0102] like Figure 2 and5 As shown, when the user operates the handle in the mode of the maximum stroke return operation, the current interpolation data calculation module performs the following process:

[0103] Based on the minimum and maximum handle opening values ​​in the new hysteresis region, the outbound path 1 is generated using the continuous interpolation method.

[0104] If the handle opening value is greater than the maximum handle opening value, a continuous interpolation method is used to generate return path 1 based on the maximum handle opening value and the minimum handle opening value in the new hysteresis region.

[0105] like Figure 3 and 6 As shown, when the user operates the handle in the middle position, the current interpolation data calculation module performs the following process:

[0106] Generate outward path 2 based on the minimum handle opening value on the new hysteresis region and the intermediate value between the maximum handle opening value and the minimum handle opening value on the new hysteresis region;

[0107] If the handle opening value decreases, a return stroke 2 is generated based on the intermediate value between the maximum handle opening value and the minimum handle opening value on the new hysteresis band area and the minimum handle opening value on the new hysteresis band area;

[0108] like Figure 4 and 7 As shown, when the user operates the handle in a zigzag return mode, the current interpolation data calculation module performs the following process:

[0109] Generate outward path 3 based on the minimum handle opening value on the new hysteresis region and the intermediate value 1 between the maximum handle opening value and the minimum handle opening value on the new hysteresis region;

[0110] If the handle opening value decreases, a return stroke 3 is generated based on an intermediate value 1 between the maximum handle opening value and the minimum handle opening value located in the new hysteresis region and based on an intermediate value 2 between the maximum handle opening value and the minimum handle opening value located in the new hysteresis region;

[0111] If the handle opening value is equal to the minimum handle opening value corresponding to the return stroke 3 and the handle opening value increases, then based on the intermediate value 2 between the maximum handle opening value and the minimum handle opening value located in the new hysteresis region and based on the intermediate value 3 between the maximum handle opening value and the minimum handle opening value located in the new hysteresis region, the outward stroke 4 is generated;

[0112] If the handle opening value is greater than the maximum handle opening value corresponding to the forward stroke 4, the forward stroke 3 is generated, and the Z-shaped operation process is completed.

[0113] Finally, the control current line of the actuator to be controlled can be obtained, specifically:

[0114] When the user operates the handle in a return operation mode with a maximum stroke, the control current line includes an outbound line and a return line that are parallel to each other, and the two endpoints of the outbound line and the return line correspond to the maximum handle opening value and the minimum handle opening value in the new hysteresis band area, respectively;

[0115] When the user operates the handle in a return operation mode at the intermediate position, the control current line includes an intersecting outbound line and a return line, the intersection of the outbound line and the return line is located between the maximum handle opening value and the minimum handle opening value on the new hysteresis band area, and the other ends of the outbound line and the return line both correspond to the minimum handle opening value on the new hysteresis band area;

[0116] When the user operates the handle in a Z-shaped return operation mode, the control current line includes multiple intersecting outbound lines and return lines, one end of the first outbound line and the last return line corresponds to the minimum handle opening value on the new hysteresis loop area, and the other ends are both located between the maximum and minimum handle opening values ​​on the new hysteresis loop area, and both ends of the remaining outbound lines and return lines are both located between the maximum and minimum handle opening values ​​on the new hysteresis loop area.

[0117] In a specific implementation of an embodiment of the present invention, the number of new hysteresis regions is equal to the number of actuators to be controlled, and the number of control current lines output by the current interpolation data calculation module is also equal to the number of actuators to be controlled; the execution module includes a proportional main valve output execution module and a variable main pump output execution module, both of which are connected to the output end of the current interpolation data calculation module, and generate corresponding control instructions based on the proportional main valve control current line and the variable main pump control current line output by the current interpolation data calculation module, and then send them to the proportional main valve and the variable main pump. In the specific implementation process, the proportional main valve output execution module: converts the proportional valve current of the current interpolation data calculation module into PWM output, drives the proportional valve, and realizes continuous adjustment of the action speed and action direction of the proportional main valve; the variable main pump output execution module: converts the oil pump current of the current interpolation data calculation module into PWM output, drives the oil pump variable mechanism, and realizes continuous adjustment of the action speed of the oil pump variable mechanism.

[0118] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A current interpolation system for an electro-hydraulic proportional control system, characterized by: It includes a detection unit, a calculation unit and an execution unit; The detection unit collects handle data and workload data, and its output end is connected to the input end of the calculation unit; The computing unit calculates a plurality of handle opening values ​​based on the handle data output by the detection unit, and further adjusts the width of the original hysteresis band based on the workload data output by the detection unit to generate a new hysteresis band. Finally, based on the handle opening values ​​and the new hysteresis band, a control current line of the actuator to be controlled is calculated using a continuous interpolation method. The execution unit is connected to the operation unit, receives the control current line of the actuator to be controlled, converts it into a control instruction and sends it to the corresponding actuator; The detection unit includes a user manipulation action detection module and a workload status detection module that are independent of each other; The user manipulation motion detection module collects the motion direction, motion position and motion acceleration of the handle; The working load state detection module collects the pressure load state of the crane and the temperature load state of the working medium in the hydraulic system of the crane; The computing unit includes a user manipulation intention recognition module and a current interpolation data calculation module; The user manipulation intention recognition module removes abnormal data in the received handle data and smoothes step data in the handle data to obtain the handle's movement direction, movement position, and movement acceleration, and calculates a number of handle opening values ​​based on the handle's movement direction, movement position, and movement acceleration; The current interpolation data calculation module is connected to the workload state detection module and the user manipulation intention recognition module, respectively. Based on the crane pressure load state output by the workload state detection module and the temperature load state of the working medium in the crane hydraulic system, the width of the original hysteresis loop region pre-stored in the current interpolation data calculation module is adjusted to generate a new hysteresis loop region. Based on several handle opening values ​​output by the user manipulation intention recognition module and the new hysteresis loop region, a continuous interpolation method is used to calculate the control current line of the actuator to be controlled.

2. The current interpolation system for an electro-hydraulic proportional control system according to claim 1, characterized in that: The current interpolation system further includes a human-machine interface unit, which is connected to the operation unit and performs parameter setting on the operation unit.

3. The current interpolation system for an electro-hydraulic proportional control system according to claim 2, characterized in that: The human-machine interface unit is also connected to the detection unit and the execution unit, and is used to display the collected handle data, workload data and control current lines of each actuator to be controlled.

4. The current interpolation system for an electro-hydraulic proportional control system according to claim 1, characterized in that: The control current line of the actuator to be controlled is specifically: When the user operates the handle in a return operation mode with a maximum stroke, the control current line includes an outbound line and a return line that are parallel to each other, and the two endpoints of the outbound line and the return line correspond to the maximum handle opening value and the minimum handle opening value in the new hysteresis band area, respectively; When the user operates the handle in a return operation mode at the intermediate position, the control current line includes an intersecting outbound line and a return line, the intersection of the outbound line and the return line is located between the maximum handle opening value and the minimum handle opening value on the new hysteresis band area, and the other ends of the outbound line and the return line both correspond to the minimum handle opening value on the new hysteresis band area; When the user operates the handle in a Z-shaped return operation mode, the control current line includes multiple intersecting outbound lines and return lines, one end of the first outbound line and the last return line corresponds to the minimum handle opening value on the new hysteresis loop area, and the other ends are both located between the maximum and minimum handle opening values ​​on the new hysteresis loop area, and both ends of the remaining outbound lines and return lines are both located between the maximum and minimum handle opening values ​​on the new hysteresis loop area.

5. A current interpolation method for an electro-hydraulic proportional control system, characterized in that: include: collecting handle data and workload data using a detection unit, and sending the handle data and workload data to a calculation unit; A plurality of handle opening values ​​are calculated by a computing unit based on handle data output by a detection unit, a width of an original hysteresis band is adjusted based on workload data output by the detection unit to generate a new hysteresis band, and a control current line of the actuator to be controlled is calculated using a continuous interpolation method based on the handle opening value and the new hysteresis band; The execution unit receives the control current line of the actuator to be controlled output by the operation unit, converts it into a control instruction and sends it to the corresponding actuator; The detection unit includes a user manipulation action detection module and a workload status detection module that are independent of each other; The user manipulation motion detection module collects the motion direction, motion position and motion acceleration of the handle; The working load state detection module collects the pressure load state of the crane and the temperature load state of the working medium in the hydraulic system of the crane; The computing unit includes a user manipulation intention recognition module and a current interpolation data calculation module; The user manipulation intention recognition module removes abnormal data in the received handle data and smoothes step data in the handle data to obtain the handle's movement direction, movement position, and movement acceleration, and calculates a number of handle opening values ​​based on the handle's movement direction, movement position, and movement acceleration; The current interpolation data calculation module is connected to the workload state detection module and the user manipulation intention recognition module, respectively. Based on the crane pressure load state output by the workload state detection module and the temperature load state of the working medium in the crane hydraulic system, the width of the original hysteresis loop region pre-stored in the current interpolation data calculation module is adjusted to generate a new hysteresis loop region. Based on several handle opening values ​​output by the user manipulation intention recognition module and the new hysteresis loop region, a continuous interpolation method is used to calculate the control current line of the actuator to be controlled.

6. The current interpolation method for an electro-hydraulic proportional control system according to claim 5, characterized in that: The current interpolation method further includes: The human-machine interface unit is used to set parameters of the operation unit, and the human-machine interface unit is used to receive handle data, workload data and control current lines of each actuator to be controlled in the detection unit and the execution unit, and display them.

7. The current interpolation method for an electro-hydraulic proportional control system according to claim 5, characterized in that: The control current line of the actuator to be controlled is specifically: When the user operates the handle in a return operation mode with a maximum stroke, the control current line includes an outbound line and a return line that are parallel to each other, and the two endpoints of the outbound line and the return line correspond to the maximum handle opening value and the minimum handle opening value in the new hysteresis band area, respectively; When the user operates the handle in a return operation mode at the intermediate position, the control current line includes an intersecting outbound line and a return line, the intersection of the outbound line and the return line is located between the maximum handle opening value and the minimum handle opening value on the new hysteresis band area, and the other ends of the outbound line and the return line both correspond to the minimum handle opening value on the new hysteresis band area; When the user operates the handle in a Z-shaped return operation mode, the control current line includes multiple intersecting outbound lines and return lines, one end of the first outbound line and the last return line corresponds to the minimum handle opening value on the new hysteresis loop area, and the other ends are both located between the maximum and minimum handle opening values ​​on the new hysteresis loop area, and both ends of the remaining outbound lines and return lines are both located between the maximum and minimum handle opening values ​​on the new hysteresis loop area.

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