Error correction method, double-cylinder forklift, error correction device, and electronic device

Abstract

The present application relates to an error correction method, a double-cylinder forklift, an error correction device, and an electronic device. The error correction method includes: obtaining a first displacement amount and a second displacement amount, where the first displacement amount is the real-time displacement amount of a first hydraulic cylinder, and the second displacement amount is the real-time displacement amount of a second hydraulic cylinder; obtaining a displacement deviation amount based on the first displacement amount and the second displacement amount; determining a correction amount based on the displacement deviation amount and a preset mapping relationship, where the preset mapping relationship is obtained based on the correlation between a dynamic load and the first displacement amount and the second displacement amount, and represents the mapping relationship between the displacement deviation amount and the correction amount, and the dynamic load acts on the sprocket; correcting the displacement deviation of the first hydraulic cylinder and the second hydraulic cylinder based on the correction amount. Through the present application, the problem of low accuracy in eliminating double-cylinder errors is solved, and the technical effect of improving the accuracy of eliminating double-cylinder errors is achieved.

Description

Technical Field

[0001] The present application relates to the field of intelligent control, and particularly to an error correction method, a double-cylinder forklift, an error correction device, and an electronic device. Background Art

[0002] With the continuous development of the forklift industry and the continuous increase in the lifting weight requirement, relying on a stronger power system, double-cylinder lifting forklifts have begun to replace single-cylinder lifting forklifts in heavy-duty scenarios. In addition, compared with single-cylinder forklifts, the distance between the support points of double-cylinder forklifts and the pallet is closer than that between single-cylinder forklifts and the pallet. Therefore, the lifting mechanism of double-cylinder forklifts is not easily deformed, has a longer service life, and lower maintenance costs. However, although double-cylinder forklifts have a larger load and can lift heavier objects, they also pose higher requirements for the double-cylinder synchronization of forklifts. Especially after the long-term use and wear of the forklift lifting mechanism, the synchronization difference between the two hydraulic cylinders will become more obvious. When the synchronization difference is too large, problems such as the pallet getting stuck or jumping during lifting may even occur. If the pallet gets stuck, manual intervention and troubleshooting are required, which will greatly reduce the work efficiency. At the same time, electric forklifts in modern logistics factories are gradually realizing unmanned operation. Therefore, automatic double-cylinder error correction has become an urgent need for unmanned forklifts.

[0003] Currently, the main solution to the double-cylinder synchronization problem is to use a flow dividing and collecting valve or multiple balance valves to improve the double-cylinder synchronization performance. However, the existing adjustment methods are for the double-cylinder synchronization adjustment of linear loads or linear motions, and this adjustment method regards the load as a constant load. However, forklifts adopt a chain drive method, and this method will generate a dynamic load due to the polygon effect, that is, the force on the sprocket will change periodically due to the rotation of the gear. The accuracy of double-cylinder forklift synchronization adjustment using the double-cylinder synchronization adjustment method for linear motion is relatively low.

[0004] Regarding the problem of low accuracy of double-cylinder error correction in the related art, no effective solution has been proposed yet. Summary of the Invention

[0005] In this embodiment, an error correction method, a double-cylinder forklift, an error correction device, and an electronic device are provided to solve the problem of low accuracy of double-cylinder forklift error correction in the related art.

[0006] In the first aspect, in this embodiment, an error correction method is provided, which is applied to a double-cylinder forklift. The double-cylinder forklift includes a first hydraulic cylinder, a second hydraulic cylinder, and a sprocket. The error correction method includes:

[0007] Obtain a first displacement and a second displacement, where the first displacement is the real-time displacement of a first hydraulic cylinder, and the second displacement is the real-time displacement of a second hydraulic cylinder;

[0008] Obtain a displacement deviation based on the first displacement and the second displacement;

[0009] Determine a correction amount based on the displacement deviation and a preset mapping relationship. The preset mapping relationship is obtained based on the correlation between the dynamic load and the first displacement and the second displacement, and represents the mapping relationship between the displacement deviation and the correction amount. The dynamic load acts on the sprocket;

[0010] Correct the displacement deviation of the first hydraulic cylinder and the second hydraulic cylinder based on the correction amount.

[0011] In one embodiment, before determining the correction amount based on the displacement deviation and the preset mapping relationship, it includes: comparing the displacement deviation with a preset threshold. If the displacement deviation is greater than the preset threshold, then determine the correction amount.

[0012] In one embodiment, determining the correction amount based on the displacement deviation and the preset mapping relationship includes: determining the real-time state of the sprocket based on the displacement deviation; determining the correction amount based on the real-time state and the preset mapping relationship.

[0013] In one embodiment, correcting the displacement deviation of the first hydraulic cylinder and the second hydraulic cylinder based on the correction amount includes: determining an adjustment signal based on the correction amount; adjusting a first proportional valve and a second proportional valve based on the adjustment signal to correct the displacement deviation. The first proportional valve is connected to the first hydraulic cylinder, and the second proportional valve is connected to the second hydraulic cylinder.

[0014] In one embodiment, before correcting the displacement deviation of the first hydraulic cylinder and the second hydraulic cylinder based on the correction amount, it further includes: obtaining a first flow rate and a second flow rate, where the first flow rate is the real-time flow rate of the first hydraulic cylinder, and the second flow rate is the real-time flow rate of the second hydraulic cylinder; correcting the displacement deviation of the first hydraulic cylinder and the second hydraulic cylinder based on the correction amount further includes: determining an adjustment signal based on the correction amount, the first flow rate, and the second flow rate; correcting the displacement deviation of the first hydraulic cylinder and the second hydraulic cylinder based on the adjustment signal.

[0015] Second aspect, in this embodiment, a double-cylinder forklift is provided. The double-cylinder forklift includes a first hydraulic cylinder, a second hydraulic cylinder, a sprocket, a sensor module, a first proportional valve, a second proportional valve, a lifting mechanism, and a controller. The sensor module, the first proportional valve, and the second proportional valve are respectively connected to the controller. The first proportional valve is connected to the first hydraulic cylinder, the second proportional valve is connected to the second hydraulic cylinder, the first hydraulic cylinder and the second hydraulic cylinder are respectively connected to the sprocket, and the sprocket is connected to the lifting mechanism. Wherein: The first hydraulic cylinder and the second hydraulic cylinder are used to drive the sprocket to rotate based on the adjustment of the first proportional valve and the second proportional valve; The sprocket is used to drive the lifting mechanism to move; The sensor module is used to obtain the real-time states of the first hydraulic cylinder and the second hydraulic cylinder and send them to the controller; The first proportional valve and the second proportional valve are used to adjust the real-time states of the first hydraulic cylinder and the second hydraulic cylinder according to the control signal of the controller; The controller is used to implement the error correction method described in the first aspect above.

[0016] In one of the embodiments, the sensor module includes a flow sensor and a magnetostrictive displacement sensor.

[0017] Third aspect, in this embodiment, an error correction device is provided, including:

[0018] An acquisition module, configured to acquire a first displacement amount and a second displacement amount, where the first displacement amount is the real-time displacement amount of the first hydraulic cylinder, and the second displacement amount is the real-time displacement amount of the second hydraulic cylinder;

[0019] A calculation module, configured to obtain a displacement deviation amount based on the first displacement amount and the second displacement amount;

[0020] A processing module, configured to determine a correction amount based on the displacement deviation amount and a preset mapping relationship. The preset mapping relationship is obtained based on the correlation relationship between the dynamic load and the first displacement amount and the second displacement amount, and represents the mapping relationship between the displacement deviation amount and the correction amount. The dynamic load acts on the sprocket;

[0021] A correction module, configured to correct the displacement deviation of the first hydraulic cylinder and the second hydraulic cylinder based on the correction module.

[0022] Fourth aspect, in this embodiment, an electronic device is provided, including a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the computer program, the error correction method described in the first aspect above is implemented.

[0023] In a fifth aspect, in the present embodiment, a storage medium is provided, on which a computer program is stored, and when the program is executed by a processor, the error correction method described in the first aspect above is implemented.

[0024] Compared with the related art, the error correction method provided in the present embodiment is applied to a double-cylinder forklift, and the double-cylinder forklift includes a first hydraulic cylinder, a second hydraulic cylinder, and a sprocket. By obtaining a first displacement and a second displacement, the first displacement is the real-time displacement of the first hydraulic cylinder, and the second displacement is the real-time displacement of the second hydraulic cylinder; a displacement deviation is obtained based on the first displacement and the second displacement; based on the displacement deviation and a preset mapping relationship, a correction amount is determined. The preset mapping relationship is obtained based on the correlation between the dynamic load and the first displacement and the second displacement, and represents the mapping relationship between the displacement deviation and the correction amount. The dynamic load acts on the sprocket; the displacement deviation of the first hydraulic cylinder and the second hydraulic cylinder is corrected based on the correction amount, solving the problem of low accuracy of double-cylinder error correction and achieving the technical effect of improving the accuracy of double-cylinder error elimination.

[0025] Details of one or more embodiments of the present application are set forth in the following drawings and description, so that other features, objects, and advantages of the present application will become more clearly understood. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation of the present application. In the drawings:

[0027] Figure 1 is a schematic diagram of the mechanical system of a double-cylinder forklift according to an embodiment of the present application;

[0028] Figure 2 is a flowchart of the error correction method of the present embodiment;

[0029] Figure 3 is a schematic diagram of the force analysis of the sprocket in the error correction method according to an embodiment of the present application;

[0030] Figure 4 is a schematic diagram of the electrical system control principle of the error correction method according to an embodiment of the present application;

[0031] Figure 5 is a schematic diagram of the effect of the error correction method according to an embodiment of the present application;

[0032] Figure 6 is a schematic diagram of the hydraulic system of a double-cylinder forklift according to an embodiment of the present application;

[0033] Figure 7It is a structural block diagram of the error correction device in this embodiment. Detailed implementation manners

[0034] To understand the purpose, technical solution and advantages of this application more clearly, the following describes and explains this application in combination with the accompanying drawings and embodiments.

[0035] Unless otherwise defined, the technical terms or scientific terms involved in this application shall have the general meaning understood by those with ordinary skills in the technical field to which this application belongs. In this application, words such as "a", "one", "kind", "the", "these" and the like do not indicate a limitation in quantity, and they can be singular or plural. The terms "include", "comprise", "have" and any variants thereof involved in this application are intended to cover non-exclusive inclusion; for example, a process, method, system, product or device including a series of steps or modules (units) is not limited to the listed steps or modules (units), but may include unlisted steps or modules (units), or may include other steps or modules (units) inherent in these processes, methods, products or devices. The terms "connect", "be connected", "be coupled" and the like involved in this application are not limited to physical or mechanical connections, but may include electrical connections, whether directly or indirectly. The "multiple" involved in this application means two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships can exist. For example, "A and / or B" can mean: A exists alone, A and B exist simultaneously, and B exists alone. Usually, the character " / " means that the objects associated before and after are in an "or" relationship. The terms "first", "second", "third" and the like involved in this application are only used to distinguish similar objects and do not represent a specific sorting of the objects.

[0036] In this embodiment, a double-cylinder forklift is provided, and the double-cylinder forklift mainly includes a mechanical system and a hydraulic system. Figure 1 It is a schematic diagram of the mechanical system of the double-cylinder forklift according to the embodiment of this application. As Figure 1 shown, the mechanical system includes a pallet 1, support wheels 2, a hydraulic cylinder 3, a chain 4, a mast 5, a fixing plate 6, a displacement sensor 7, a lifting plate 8, a sprocket 9, a pipe joint 10, an electric controller 11, a flow sensor 12 and a folding plate 13.

[0037] Specifically, the pallet 1 is fixed to the bottom of the gantry 5 by welding and can move up and down with the gantry 5. It is used to insert into the bottom of the storage bracket to support the object to be lifted. The support wheels 2 are installed at the bottom of the vehicle body through components such as bearings, optical axes, and pressing blocks. The support wheels 2 do not move up and down with the gantry 5; the support wheels 2 are used to cooperate with the driving wheels at the rear of the forklift to achieve the movement function and at the same time support the entire vehicle body. The hydraulic cylinders 3 in this mechanical system include two horizontally arranged hydraulic cylinders, denoted as the first hydraulic cylinder and the second hydraulic cylinder; the lower ends of the hydraulic cylinders 3 are fixed to the bottom of the vehicle body, the middle of the cylinder body is locked to the vehicle body by a hoop, and the upper end of the cylinder body is fixed together with the lifting plate 8; the hydraulic cylinders 3 are hydraulically driven to achieve the lifting and lowering function of the lifting mechanism. The upper end of the chain 4 is fixed to the fixing plate 6 through the pipe joint 10, and the chain 4 is fixed to the bottom of the vehicle body through the joint. Together with the sprocket 9, it can achieve chain drive. The gantry 5 is welded by multiple steel bars and square steels. Pulleys are installed on both sides of the gantry 5, and the pulleys can move up and down in the vehicle body guide rails to fix components such as the pallet 1. The fixing plate 6 is a thick steel plate installed on the top of the vehicle body to fix components such as the chain 4. There are two displacement sensors 7, which are respectively installed at the push rods of the two hydraulic cylinders. The displacement sensors are magnetostrictive displacement sensors, which are used to detect the displacement change amount of the hydraulic cylinders 3. The lifting plate 8 is installed on the gantry 5, and both sides of the lifting plate 8 are connected to the push rods of the hydraulic cylinders 3 to transmit the telescopic movement of the hydraulic cylinders 3 to the gantry 5 and the pallet 1. The sprocket 9 is installed on the lifting plate 8 through components such as bearings and optical axes, and cooperates with the chain 4 to transmit the movement form of the lifting plate 8 to the gantry 5 through chain drive. The pipe joint 10 is used in cooperation with the fixing screws at both ends of the chain 4 to fix the chain 4 to the fixing plate 6 and the vehicle body. The electric controller 11 is installed at the rear of the vehicle body and is mainly composed of multiple buttons and joysticks, which are used to control the forklift to drive and carry goods. There are two flow sensors 12, which are respectively installed on the external oil pipe lines of the rodless chambers of the hydraulic cylinders 3 to measure the inflow and outflow of the hydraulic cylinders 3. The folding plate 13 is installed at the rear of the vehicle body and can be manually folded to provide a standing space for the operator during operation.

[0038] In this embodiment, an error correction method is provided, which is applied to a double-cylinder forklift. The double-cylinder forklift includes a first hydraulic cylinder, a second hydraulic cylinder, and a sprocket. Figure 2 is a flowchart of the error correction method of this embodiment, as Figure 2 shown. This process includes the following steps:

[0039] Step S201, obtain a first displacement amount and a second displacement amount. The first displacement amount is the real-time displacement amount of the first hydraulic cylinder, and the second displacement amount is the real-time displacement amount of the second hydraulic cylinder.

[0040] Specifically, a hydraulic cylinder is a hydraulic actuator that converts hydraulic energy into mechanical energy and performs linear reciprocating motion. The structural forms of hydraulic cylinders are mainly divided into three categories: piston cylinders, plunger cylinders, and swing cylinders. Piston cylinders and plunger cylinders achieve reciprocating motion to output speed and thrust, and swing cylinders achieve reciprocating swing to output angular velocity and torque. The hydraulic cylinder in this embodiment mainly refers to a plunger cylinder or a piston cylinder. The real-time position of the push rod in the hydraulic cylinder is recorded by a displacement sensor to determine the real-time displacement of the hydraulic cylinder. The first displacement is obtained according to the real-time displacement in the first hydraulic cylinder; the second displacement is obtained according to the real-time displacement in the second hydraulic cylinder.

[0041] Step S202: Obtain a displacement deviation based on the first displacement and the second displacement.

[0042] Specifically, the first displacement can characterize the strength of the real-time power provided by the first hydraulic cylinder, and the second displacement can characterize the strength of the real-time power provided by the second hydraulic cylinder. Since the application scenario in this embodiment is a double-cylinder forklift, it is necessary for the first hydraulic cylinder and the second hydraulic cylinder to be synchronized, which means that the power provided by the two hydraulic cylinders should be as identical as possible. After obtaining the first displacement and the second displacement, the difference between the first displacement and the second displacement is calculated to determine the displacement deviation between the first hydraulic cylinder and the second hydraulic cylinder. The displacement deviation characterizes the double-cylinder synchronization of the double-cylinder forklift. The smaller the displacement deviation, the better the double-cylinder synchronization; the larger the displacement deviation, the worse the double-cylinder synchronization.

[0043] Step S203: Determine a correction amount based on the displacement deviation and a preset mapping relationship. The preset mapping relationship is obtained based on the correlation between the dynamic load and the first displacement and the second displacement, and characterizes the mapping relationship between the displacement deviation and the correction amount. The dynamic load acts on the sprocket.

[0044] Specifically, the preset mapping relationship represents the mapping relationship between the displacement deviation and the correction amount. When performing double-cylinder error correction, the correction amount can be determined based on the displacement deviation and the preset mapping relationship. The preset mapping relationship mainly includes two parts. One is the first adjustment amount determined according to the current displacement deviation by traditional linear motion analysis. The other is the correlation between the real-time displacement of the hydraulic cylinder and the dynamic load determined by analyzing the forces on the sprocket. The second adjustment amount is determined based on the real-time displacement of the hydraulic cylinder and this correlation. The first adjustment amount is corrected by the second adjustment amount to obtain the correction amount. The dynamic load is caused by the polygon effect under the chain drive condition. The sprocket is a typical polygon structure, and the polygon effect will occur when using the chain-sprocket pair mechanism for transmission. The polygon effect means that when the chain enters the driving sprocket, every time the sprocket rotates one tooth, the chain speed in the horizontal direction changes from small to large and then from large to small once, and at the same time, the chain moves up and down in the vertical direction once. The existence of the polygon causes the unevenness of the chain drive motion. The polygon effect is affected by the pitch of the sprocket teeth. The changes in the chain speed and transmission ratio cause acceleration in the chain drive, thus generating a dynamic load, that is, the dynamic load. In this embodiment, based on the unique deviation of the first hydraulic cylinder and the second hydraulic cylinder, the displacement of the first hydraulic cylinder and / or the second hydraulic cylinder that needs to be adjusted currently is determined, and according to the preset mapping relationship, the real-time state of the sprocket and the magnitude of the dynamic load are determined when adjusting based on this displacement. The displacement to be adjusted is further corrected based on the dynamic load to determine the correction amount. The correction amount is the displacement of the hydraulic cylinder that finally controls the hydraulic cylinder to make adjustments. The error correction method in this embodiment establishes the correlation between the dynamic load, the first displacement, and the second displacement based on the periodic load action law of the chain-sprocket pair. Determining the correction amount based on the displacement deviation and the preset mapping relationship can make the adjustment process better adapt to the impact condition of the sprocket dynamic load, eliminate the polygon effect of the sprocket, avoid oscillation during the error adjustment process, avoid the extension of the adjustment period, and can effectively improve the error correction efficiency and the accuracy of error correction.

[0045] Step S204, correct the displacement deviation of the first hydraulic cylinder and the second hydraulic cylinder based on the correction amount.

[0046] Specifically, after determining the correction amount, the control system adjusts the valve opening by generating an adjustment signal to control the hydraulic oil flow rate in the hydraulic cylinder, thereby achieving real-time adjustment of the displacement amount of the hydraulic cylinder and achieving the technical effect of accurately correcting the double-cylinder synchronization error. In one embodiment, the first displacement amount of the first hydraulic cylinder can be adjusted based on the correction amount alone, or the second displacement amount of the second hydraulic cylinder can be adjusted based on the correction amount alone, or the first displacement amount of the first hydraulic cylinder and the second displacement amount of the second hydraulic cylinder can be adjusted simultaneously based on the correction amount. Preferably, adjusting the first displacement amount of the first hydraulic cylinder and the second displacement amount of the second hydraulic cylinder simultaneously based on the first correction amount can effectively improve the correction efficiency of the double-cylinder error.

[0047] Through the above steps, the error correction method of the embodiment of the present application can adapt to the impact working condition of the sprocket dynamic load, eliminate the sprocket polygon effect, avoid oscillation during the error adjustment process, avoid the extension of the adjustment period, and effectively improve the error correction efficiency and the accuracy of error correction.

[0048] In one embodiment, before determining the correction amount based on the displacement deviation amount and the preset mapping relationship, it includes: comparing the displacement deviation amount with a preset threshold, and if the displacement deviation amount is greater than the preset threshold, determining the correction amount.

[0049] Specifically, the displacement deviation amount reflects the double-cylinder synchronization of the double-cylinder forklift. Ideally, the real-time displacement amounts of the double-cylinder forklift should be the same, that is, the displacement deviation amount is 0. However, in actual applications, due to many reasons such as equipment accuracy and equipment wear, it is very difficult for the first hydraulic cylinder and the second hydraulic cylinder to achieve complete synchronization. Therefore, an acceptable range can be defined for the double-cylinder synchronization as a quantitative index, that is, a preset threshold is set for the displacement deviation amount. If the displacement deviation amount is less than the preset threshold, it means that the current double-cylinder synchronization is good and the double-cylinder forklift is in a normal operating condition; if the displacement deviation amount is greater than or equal to the preset threshold, it means that the current double-cylinder synchronization is poor, which may cause equipment failures and requires starting the synchronous error correction.

[0050] In one embodiment, determining the correction amount based on the displacement deviation amount and the preset mapping relationship includes: determining the real-time state of the sprocket based on the displacement deviation amount; determining the correction amount based on the real-time state and the preset mapping relationship.

[0051] Specifically, in this application, by analyzing the forces acting on the sprocket, a preset mapping relationship between the real-time displacement and the dynamic load is determined. When adjusting the displacement deviation, based on the real-time displacement of the hydraulic cylinder, the position of the sprocket during the adjustment of the displacement deviation is determined. Each rotation of a tooth of the sprocket is an adjustment cycle, and the real-time position of the sprocket during this adjustment process is the real-time state. The dynamic load corresponding to this real-time state is obtained, and the correction amount is determined based on the dynamic load and the displacement deviation.

[0052] The error correction principle of the traditional double-cylinder error correction method for hydraulic cylinders is to detect the difference in the displacements of the push rods of the two hydraulic cylinders in real time, and then adjust the flow rates input to the two hydraulic cylinders to achieve error correction. However, such a correction method is only applicable to constant loads and is difficult to adapt to variable loads. In the lifting structure of a double-cylinder forklift, a chain sprocket pair is used for chain drive. Due to the polygon effect of the chain sprocket pair, the speed of the chain continuously changes periodically during movement, resulting in the entire lifting mechanism being continuously impacted by dynamic loads. Therefore, if the traditional error adjustment method is still used, the synchronous error will also oscillate periodically, the correction period will be extended, and the accuracy of error correction will be low. To better adapt to the periodic dynamic load impact of the chain sprocket pair, this application first analyzes the forces acting on the sprocket to determine the preset mapping relationship.

[0053] Figure 3 It is a schematic diagram of the force analysis of the sprocket according to the error correction method described in the embodiments of this application. Here, the first hydraulic cylinder and the connected sprocket are taken as examples for illustration. As Figure 3 shown, the force situation of the sprocket is as follows:

[0054] (P 1无 S1 - P 1有 S2) - F 动 = m1a

[0055] Among them, m1 represents the mass of the sprocket, a represents the acceleration of the sprocket, P 1无 represents the pressure in the rodless cavity of the first hydraulic cylinder, S1 represents the cross-sectional area of the rodless cavity, P 1有 represents the pressure in the rod chamber of the first hydraulic cylinder, S2 represents the cross-sectional area of the rod chamber, F 动 represents the dynamic force on the chain; differentiating the force formula of the sprocket gives the following differential form:

[0056]

[0057] Among them, h1 represents the displacement of the push rod of the first hydraulic cylinder. At the same time, this embodiment also analyzes the sprocket speed. The main reason for the generation of dynamic load is that the polygon effect of the sprocket causes the angular velocity of the chain movement to change, which causes the linear velocity of the entire lifting mechanism to change periodically. The magnitude of the linear velocity is:

[0058] v y = R1w1sinα

[0059] where w1 represents the angular velocity of the sprocket, R1 represents the radius of the sprocket, α represents the angle formed by the current tooth and the vertical Y-axis, and v y represents the speed of the chain, that is, the velocity component of the sprocket on the y-axis; at the same time, in the static state, its force condition is:

[0060] F 静 = 2m2g

[0061] where F 静 represents the force in the static state, and m2 represents the lifting load.

[0062] Expanding to the dynamic force condition, the sum of the forces on the entire single sprocket is:

[0063]

[0064] where F i represents the force on each tooth; decomposing it onto the contact arc length of each tooth, it is expressed as:

[0065]

[0066] where θ1 represents the starting angle of the force on the first tooth, θ2 represents the ending angle of the force on the first tooth, and β represents the uniform distribution angle of each tooth on the circumference. Therefore, the relationship between the dynamic load F 动 and the displacement h1 of the first hydraulic cylinder is established. When the displacement difference between the two cylinders is detected, through the above model, error adjustment with periodic adaptation can be performed for the dynamic load condition, and such periodic adjustment is output to the proportional valve to correct the synchronization error of the two cylinders.

[0067] In one of the embodiments, the correction of the displacement deviation of the first hydraulic cylinder and the second hydraulic cylinder based on the correction amount includes: determining an adjustment signal based on the correction amount; adjusting a first proportional valve and a second proportional valve based on the adjustment signal to correct the displacement deviation, where the first proportional valve is connected to the first hydraulic cylinder and the second proportional valve is connected to the second hydraulic cylinder. Specifically, by adjusting the opening degree of the proportional valve, the flow rate of the hydraulic oil entering the hydraulic cylinder can be adjusted. After determining the correction amount, taking the displacement adjustment amount of the current cycle as the correction amount, then according to the correction amount and the cross-sectional area of the hydraulic cylinder, the volume of the hydraulic oil to be input can be determined. Based on the volume of the hydraulic oil to be input and the length of the adjustment cycle, combined with the real-time flow rate of the proportional valve, the adjustment amount of the proportional valve can be determined. To improve the correction efficiency, the first proportional valve and the second proportional valve can be adjusted simultaneously. For the hydraulic cylinder with a smaller real-time displacement amount, increase the opening degree of its proportional valve; for the hydraulic cylinder with a larger real-time displacement amount, decrease the opening degree of its proportional valve to make them tend to be synchronized. Compared with the traditional forklift using a balance valve to ensure the double-cylinder synchronization accuracy, using a proportional valve to control the double-cylinder flow rate makes the actual output more consistent with the theoretical control amount.

[0068] In one of the embodiments, before the correction of the displacement deviation of the first hydraulic cylinder and the second hydraulic cylinder based on the correction amount, it further includes: obtaining a first flow rate and a second flow rate, where the first flow rate is the real-time flow rate of the first hydraulic cylinder and the second flow rate is the real-time flow rate of the second hydraulic cylinder; the correction of the displacement deviation of the first hydraulic cylinder and the second hydraulic cylinder based on the correction amount further includes: determining an adjustment signal based on the correction amount, the first flow rate, and the second flow rate; correcting the displacement deviation of the first hydraulic cylinder and the second hydraulic cylinder based on the adjustment signal. Specifically, by obtaining the real-time flow rate and adjusting the real-time flow rate. Compared with the traditional single-variable feedback control, the error correction method of this embodiment. Adopts multi-variable servo control, simultaneously collects the displacement of the hydraulic cylinder push rod and the flow rate of the rodless chambers of the double cylinders, and establishes multiple feedback loops, significantly improving the accuracy and timeliness of error elimination.

[0069] In one of the embodiments, the error correction method is implemented through an electrical control system. The electrical control system mainly includes a three-position four-way electromagnetic proportional valve, a flow sensor, a magnetostrictive linear sensor, and a control main board. Figure 4 is the electrical system control schematic diagram of the error correction method according to the embodiment of the present application, as Figure 4As shown, first, the flow rate of the rodless chamber of the hydraulic cylinder and the displacement of the hydraulic cylinder push rod are detected in real time. When the displacement difference between the two cylinders is detected to be greater than the preset threshold, the error correction algorithm is triggered. Subsequently, the specific position of the current sprocket and chain in the dynamic load change cycle is calculated based on the collected displacement. Then, starting from the current position as the actual position, corresponding periodic adjustment signals are output to the two proportional valves. Among them, the adjustment signal of the proportional valve corresponding to the circuit with a large displacement is the original signal minus the periodic adjustment signal, and the adjustment signal of the proportional valve corresponding to the circuit with a small displacement is the original signal plus the periodic adjustment signal. A new proportional valve adjustment amount signal is output based on the signal collected in the next detection cycle, and the phase continues from the previous collection cycle. Finally, through continuous error correction, the double-cylinder synchronization error is eliminated.

[0070] Figure 5 is a schematic diagram of the effect of the error correction method according to an embodiment of the present application. As Figure 5 shown, through the error correction method of the above embodiment, after being applied to a double-cylinder forklift, compared with the traditional double-cylinder synchronization error correction method, it can adapt to the impact working condition of the sprocket dynamic load, eliminate the sprocket polygon effect, avoid oscillation during the error adjustment process, avoid the extension of the adjustment cycle, and effectively improve the error correction efficiency. And based on the control algorithm of the sprocket-chain kinematic pair, the relationship between the dynamic load F 动 and the displacement h1 of the hydraulic cylinder is established, and error adjustment with periodic adaptation is publicly performed for the dynamic load. In addition, for the error correction method of the present application, compared with the traditional single-variable feedback control, multi-variable servo control is adopted, the displacement of the hydraulic cylinder push rod and the flow rate of the rod chamber of the double cylinder are collected simultaneously, and multiple feedback loops are established, significantly improving the accuracy and timeliness of error elimination. In addition, for the error correction method of the embodiment of the present application, compared with the traditional forklift using a balance valve to ensure the double-cylinder synchronization accuracy, a proportional valve is used to control the double-cylinder flow rate, making the actual output more consistent with the theoretical control amount; compared with the traditional forklift using a wire-pulling encoder to collect the displacement, a magnetostrictive displacement sensor is used, making the displacement collection more accurate.

[0071] It should be noted that the steps shown in the above process or the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. And although the logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in a different order than here.

[0072] In this embodiment, a double-cylinder forklift is further provided. The double-cylinder forklift includes a first hydraulic cylinder, a second hydraulic cylinder, a sprocket, a sensor module, a first proportional valve, a second proportional valve, a lifting mechanism, and a controller. The sensor module, the first proportional valve, and the second proportional valve are respectively connected to the controller. The first proportional valve is connected to the first hydraulic cylinder, and the second proportional valve is connected to the second hydraulic cylinder. The first hydraulic cylinder and the second hydraulic cylinder are respectively connected to the sprocket, and the sprocket is connected to the lifting mechanism, where: The first hydraulic cylinder and the second hydraulic cylinder are used to drive the sprocket to rotate based on the adjustment of the first proportional valve and the second proportional valve; The sprocket is used to drive the lifting mechanism to move; The sensor module is used to obtain the real-time states of the first hydraulic cylinder and the second hydraulic cylinder and send them to the controller; The first proportional valve and the second proportional valve are used to adjust the real-time states of the first hydraulic cylinder and the second hydraulic cylinder according to the control signal of the controller; The controller is used to implement the error correction method described in any of the above embodiments.

[0073] In one of the embodiments, a hydraulic system of a double-cylinder forklift is provided. Figure 6 It is a schematic diagram of the hydraulic system of the double-cylinder forklift according to the embodiment of the present application, as Figure 6 shown. The hydraulic system includes a hydraulic cylinder 3, a hydraulic control check valve 14, a proportional valve 15, a filter 16, an oil pump 17, a fuel tank 18, a relief valve 19, and a main board 20, and also includes accessories such as oil pipes and pipe joints.

[0074] There are a total of 2 hydraulic cylinders 3, which are the actuators of the hydraulic system and can extend and retract the push rod when the internal pressure flow direction of the hydraulic system changes; There are a total of 4 hydraulic control check valves 14, which are respectively connected to the rod chamber interface and the non-rod chamber interface of the hydraulic cylinder 3, and are used to lock the hydraulic circuit when there is no active flow and prevent the hydraulic oil in the hydraulic cylinder 3 from flowing back; There are a total of 2 proportional valves 15, which are three-position four-way electro-hydraulic proportional valves 15, and are respectively connected to a check valve, a filter 16, a relief valve 19, and a fuel tank 18 at the front and back, and are used to control the liquid flow direction and flow rate of the hydraulic system. The filter 16 is connected between the proportional valve 15 and the oil pump 17 and is used to filter impurities in the hydraulic oil. The oil pump 17 is connected between the fuel tank 18 and the filter 16 and is used to provide pressure for the entire hydraulic system. The fuel tank 18 is connected to the proportional valve 15, the relief valve 19, and the oil pump 17, and is mainly used to store and provide hydraulic oil. The relief valve 19 is connected in parallel between the filter 16 and the proportional valve 15 and is mainly used to protect the gas hydraulic components by discharging fluid when the pressure of the hydraulic system is too high. The main board 20 is connected to the control coil of the proportional valve 15 and is mainly used to provide a control signal for the proportional valve 15.

[0075] In one of the embodiments, the sensor module includes a flow sensor and a magnetostrictive displacement sensor. Specifically, the magnetostrictive displacement sensor precisely measures the actual displacement value of the product to be detected by accurately detecting the absolute position of the movable magnetic ring through internal non-contact measurement and control technology. Since there is no direct contact between the movable magnetic ring and the sensitive element for determining the position in the magnetostrictive displacement sensor, the sensor can be applied in extremely harsh industrial environments and is not easily affected by oil stains, solutions, dust, or other contaminants. In addition, the sensor uses high-tech materials and advanced electronic processing technology, so it can be applied in environments with high temperature, high pressure, and high oscillation. The output signal of the sensor is the absolute displacement value. Even if the power supply is interrupted and then reconnected, the data will not be lost, and there is no need to re-zero. Since the sensitive element is non-contact, even if the detection is repeated continuously, it will not cause any wear to the sensor, which can greatly improve the reliability and service life of the detection. Compared with the traditional wire-drawing displacement sensor, the use of the magnetostrictive displacement sensor can make the displacement measurement more accurate.

[0076] In this embodiment, an error correction device is also provided. This device is used to implement the above-mentioned embodiments and preferred implementation manners, and those that have been described will not be repeated here. The following terms such as "module", "unit", "sub-unit", etc. can be a combination of software and / or hardware that can achieve a predetermined function. Although the devices described in the following embodiments are preferably implemented in software, implementation in hardware, or a combination of software and hardware is also possible and contemplated.

[0077] Figure 7 is the structural block diagram of the error correction device of this embodiment, as Figure 7 shown, this device includes:

[0078] An acquisition module 71, configured to acquire a first displacement amount and a second displacement amount, where the first displacement amount is the real-time displacement amount of the first hydraulic cylinder, and the second displacement amount is the real-time displacement amount of the second hydraulic cylinder;

[0079] A calculation module 72, configured to obtain a displacement deviation amount based on the first displacement amount and the second displacement amount;

[0080] A processing module 73, configured to determine a correction amount based on the displacement deviation amount and a preset mapping relationship. The preset mapping relationship is obtained based on the correlation relationship between the dynamic load and the first displacement amount and the second displacement amount, and represents the mapping relationship between the displacement deviation amount and the correction amount. The dynamic load acts on the sprocket;

[0081] A correction module 74, configured to correct the displacement deviation of the first hydraulic cylinder and the second hydraulic cylinder based on the correction module.

[0082] The processing module 73 is further configured to compare the displacement deviation amount with a preset threshold, and if the displacement deviation amount is greater than the preset threshold, determine the correction amount.

[0083] The processing module 73 is further configured to determine the real-time state of the sprocket based on the displacement deviation amount; and determine the correction amount based on the real-time state and the preset mapping relationship.

[0084] The correction module 74 is further configured to determine an adjustment signal based on the correction amount; and adjust the first proportional valve and the second proportional valve based on the adjustment signal to correct the displacement deviation. The first proportional valve is connected to the first hydraulic cylinder, and the second proportional valve is connected to the second hydraulic cylinder.

[0085] The correction module 74 is further configured to obtain a first flow rate and a second flow rate. The first flow rate is the real-time flow rate of the first hydraulic cylinder, and the second flow rate is the real-time flow rate of the second hydraulic cylinder. The correcting the displacement deviation of the first hydraulic cylinder and the second hydraulic cylinder based on the correction amount further includes: determining an adjustment signal based on the correction amount, the first flow rate, and the second flow rate; and correcting the displacement deviation of the first hydraulic cylinder and the second hydraulic cylinder based on the adjustment signal.

[0086] It should be noted that the above-mentioned each module can be a functional module or a program module, and can be implemented either by software or by hardware. For the modules implemented by hardware, the above-mentioned each module can be located in the same processor; or the above-mentioned each module can also be located in different processors in any combined form.

[0087] In this embodiment, an electronic device is further provided, including a memory and a processor. A computer program is stored in the memory, and the processor is configured to run the computer program to execute the steps in any one of the above method embodiments.

[0088] Optionally, the above-mentioned electronic device may further include a transmission device and an input / output device. Among them, the transmission device is connected to the above-mentioned processor, and the input / output device is connected to the above-mentioned processor.

[0089] Optionally, in this embodiment, the above-mentioned processor may be configured to execute the following steps through a computer program:

[0090] S1, obtain a first displacement amount and a second displacement amount. The first displacement amount is the real-time displacement amount of the first hydraulic cylinder, and the second displacement amount is the real-time displacement amount of the second hydraulic cylinder.

[0091] S2, obtain a displacement deviation amount based on the first displacement amount and the second displacement amount.

[0092] S3. Based on the displacement deviation and a preset mapping relationship, determine a correction amount. The preset mapping relationship is obtained based on the correlation between the dynamic load, the first displacement amount, and the second displacement amount, and represents the mapping relationship between the displacement deviation and the correction amount. The dynamic load acts on the sprocket.

[0093] S4. Based on the correction amount, correct the displacement deviation of the first hydraulic cylinder and the second hydraulic cylinder.

[0094] It should be noted that for the specific examples in this embodiment, reference can be made to the examples described in the above embodiments and optional implementation manners, and details will not be elaborated herein.

[0095] In addition, in combination with the error correction method provided in the above embodiments, a storage medium can also be provided in this embodiment to implement it. A computer program is stored on the storage medium; when the computer program is executed by a processor, any one of the error correction methods in the above embodiments is implemented.

[0096] It should be understood that the specific embodiments described here are only used to explain this application, rather than to limit it. According to the embodiments provided in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of this application.

[0097] Obviously, the drawings are only some examples or embodiments of this application. For those of ordinary skill in the art, this application can also be applied to other similar situations based on these drawings without creative efforts. Additionally, it can be understood that although the work done during the development process may be complex and time-consuming, for those of ordinary skill in the art, certain design, manufacturing, or production changes based on the technical content disclosed in this application are only conventional technical means and should not be regarded as insufficient disclosure of this application.

[0098] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data for analysis, stored data, displayed data, etc.) involved in this application are all information and data that have been authorized by the user or fully authorized by all parties.

[0099] The term "embodiment" in this application means that the specific features, structures, or characteristics described in combination with the embodiment may be included in at least one embodiment of this application. The phrase appears in various positions in the specification does not necessarily mean the same embodiment, nor does it mean being independent or alternative to other embodiments and mutually exclusive. Those of ordinary skill in the art can clearly or implicitly understand that the embodiments described in this application can be combined with other embodiments without conflict.

[0100] The above-described embodiments merely represent several implementation manners of the present application. The description thereof is relatively specific and detailed, but it should not be construed as a limitation on the scope of patent protection. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all fall within the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the appended claims.

Claims

1. An error correction method, applied to a double-cylinder forklift, the double-cylinder forklift including a first hydraulic cylinder, a second hydraulic cylinder, and a sprocket, characterized in that, The error correction method includes: Obtaining a first displacement and a second displacement, where the first displacement is the real-time displacement of a first hydraulic cylinder, and the second displacement is the real-time displacement of a second hydraulic cylinder; Obtaining a displacement deviation based on the first displacement and the second displacement; Determining a correction amount based on the displacement deviation and a preset mapping relationship, where the preset mapping relationship is obtained based on the correlation between a dynamic load and the first displacement and the second displacement, and represents the mapping relationship between the displacement deviation and the correction amount, and the dynamic load acts on the sprocket; Correcting the displacement deviation of the first hydraulic cylinder and the second hydraulic cylinder based on the correction amount; Before correcting the displacement deviation of the first hydraulic cylinder and the second hydraulic cylinder based on the correction amount, it further includes: Obtaining a first flow rate and a second flow rate, where the first flow rate is the real-time flow rate of the first hydraulic cylinder, and the second flow rate is the real-time flow rate of the second hydraulic cylinder; Correcting the displacement deviation of the first hydraulic cylinder and the second hydraulic cylinder based on the correction amount further includes: Determining an adjustment signal based on the correction amount, the first flow rate, and the second flow rate; adopting multivariable servo control, simultaneously collecting the displacement of the hydraulic cylinder push rod and the flow rate of the rodless chambers of the two cylinders, and establishing multiple feedback loops; Correcting the displacement deviation of the first hydraulic cylinder and the second hydraulic cylinder based on the adjustment signal; Adjusting a first proportional valve and a second proportional valve based on the adjustment signal to correct the displacement deviation, where the first proportional valve is connected to the first hydraulic cylinder, and the second proportional valve is connected to the second hydraulic cylinder.

2. The error correction method according to claim 1, wherein Before determining the correction amount based on the displacement deviation and the preset mapping relationship, it includes: Comparing the displacement deviation with a preset threshold, and if the displacement deviation is greater than the preset threshold, determining the correction amount.

3. The error correction method according to claim 1, characterized in that, Determining the correction amount based on the displacement deviation and the preset mapping relationship includes: Determining the real-time state of the sprocket based on the displacement deviation; Determining the correction amount based on the real-time state and the preset mapping relationship.

4. A double-cylinder forklift, characterized in that, It includes a first hydraulic cylinder, a second hydraulic cylinder, a sprocket, a sensor module, a first proportional valve, a second proportional valve, a jacking mechanism, and a controller. The sensor module, the first proportional valve, and the second proportional valve are respectively connected to the controller. The first proportional valve is connected to the first hydraulic cylinder, the second proportional valve is connected to the second hydraulic cylinder, the first hydraulic cylinder and the second hydraulic cylinder are respectively connected to the sprocket, and the sprocket is connected to the jacking mechanism, where: The first hydraulic cylinder and the second hydraulic cylinder are used to drive the sprocket to rotate based on the adjustment of the first proportional valve and the second proportional valve; The sprocket is used to drive the jacking mechanism to move; The sensor module is used to obtain the real-time state of the first hydraulic cylinder and the second hydraulic cylinder and send it to the controller; The first proportional valve and the second proportional valve are used to adjust the real-time state of the first hydraulic cylinder and the second hydraulic cylinder according to the control signal of the controller; The controller is configured to execute the error correction method according to any one of claims 1 to 3.

5. The double-cylinder forklift according to claim 4, wherein The sensor module includes a flow sensor and a magnetostrictive displacement sensor.

6. An error correction device is applied to a double-cylinder forklift. The double-cylinder forklift includes a first hydraulic cylinder, a second hydraulic cylinder, and a sprocket, and is characterized in that, The error correction device is configured to execute the error correction method according to any one of claims 1 to 3, and the error correction device includes: An acquisition module, configured to acquire a first displacement amount and a second displacement amount, where the first displacement amount is the real-time displacement amount of a first hydraulic cylinder, and the second displacement amount is the real-time displacement amount of a second hydraulic cylinder; A calculation module, configured to obtain a displacement deviation amount based on the first displacement amount and the second displacement amount; A processing module, configured to determine a correction amount based on the displacement deviation amount and a preset mapping relationship, where the preset mapping relationship is obtained based on the correlation between a dynamic load and the first displacement amount and the second displacement amount, and represents the mapping relationship between the displacement deviation amount and the correction amount, and the dynamic load acts on the sprocket; A correction module, configured to correct the displacement deviation of the first hydraulic cylinder and the second hydraulic cylinder based on the correction module; Wherein, the correction module is further configured to acquire a first flow rate and a second flow rate, where the first flow rate is the real-time flow rate of the first hydraulic cylinder, and the second flow rate is the real-time flow rate of the second hydraulic cylinder; the correcting the displacement deviation of the first hydraulic cylinder and the second hydraulic cylinder based on the correction amount further includes: determining an adjustment signal based on the correction amount, the first flow rate, and the second flow rate; adopting multivariable servo control, simultaneously collecting the displacement amount of the hydraulic cylinder push rod and the flow rate of the rodless chambers of the double cylinders, and establishing a plurality of feedback loops; correcting the displacement deviation of the first hydraulic cylinder and the second hydraulic cylinder based on the adjustment signal; adjusting a first proportional valve and a second proportional valve based on the adjustment signal to correct the displacement deviation, where the first proportional valve is connected to the first hydraulic cylinder, and the second proportional valve is connected to the second hydraulic cylinder.

7. An electronic device, comprising a memory and a processor, characterized in that, A computer program is stored in the memory, and the processor is configured to run the computer program to execute the error correction method according to any one of claims 1 to 3.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, the steps of the error correction method according to any one of claims 1 to 3 are implemented.

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