Wheel axle control method and system

Abstract

The invention relates to the technical field of linear guide rails, in particular to a wheel axle control method and system, and the method comprises the steps: obtaining a target position of a slave axle; setting a virtual wheel shaft as a main shaft and an actual wheel shaft as an auxiliary shaft; the real-time position of the main shaft and the real-time position of the auxiliary shaft are obtained; based on the real-time position of the main shaft and the real-time position of the slave shaft, calculating the position deviation of the slave shaft and the main shaft; acquiring the walking speed of the slave shaft based on the position deviation and the target position; and controlling the slave shaft to move according to the walking speed until the target position is reached. According to the wheel axle control method, the technical problem that the overall operation of the stacker is interrupted due to the failure of the main shaft in the prior art is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of linear guide rails, and particularly relates to a wheel shaft control method and system. Background Art

[0002] As a core device in modern logistics warehousing systems, stackers are widely used in cargo storage, handling, and the efficient management of three-dimensional warehouses. The stability and reliability of their traveling mechanisms directly determine the operating efficiency of stackers and the overall continuity of system operation. In the prior art, the wheel shaft drive system of stackers usually adopts a control mode in which the main shaft and the slave shaft work together, that is, by setting a main shaft (active wheel shaft) and at least one slave shaft (driven wheel shaft) to achieve synchronous drive and control of multiple wheels. As the core power output unit, the main shaft is responsible for receiving control instructions and driving the slave shaft to follow the movement, so as to ensure the consistency of the rotational speed and steering of each wheel.

[0003] However, the control method of the prior art has significant defects: Since the main shaft undertakes the core control and power transmission functions, once the main shaft fails to work properly due to mechanical failures (such as bearing damage, transmission gear failure) or electrical failures (such as motor overload, encoder abnormality), the slave shaft will not be able to operate independently, resulting in the paralysis of the entire traveling mechanism of the stacker. Such failures will not only cause equipment downtime and affect the warehousing operation efficiency, but may also cause cargo displacement or mechanical structure impact due to emergency braking, increasing maintenance costs and safety risks. In addition, after the main shaft fails, the slave shaft lacks the ability to operate independently, resulting in the need for manual intervention or overall system shutdown and maintenance during the fault recovery process, which is difficult to meet the requirements of modern logistics systems for high availability and rapid fault recovery.

[0004] Therefore, there is an urgent need for a new type of wheel shaft drive control method and system, which can ensure the multi-axis synchronization accuracy while improving the fault tolerance and fault isolation performance of the system, so as to avoid the interruption of the overall operation of the stacker caused by the failure of the main shaft and affect the stable operation of the stacker.

[0005] Therefore, the prior art needs to be further developed. Summary of the Invention

[0006] The purpose of the present invention is to overcome the above technical deficiencies and provide a wheel shaft control method and system to solve the technical problem of the interruption of the overall operation of the stacker caused by the failure of the main shaft in the related art.

[0007] To achieve the above technical objectives, the present invention adopts the following technical solutions: A wheel shaft control method is provided, including: obtaining the target position of the slave shaft; setting a virtual wheel shaft as the master shaft and the actual wheel shaft as the slave shaft; obtaining the real-time position of the master shaft and the real-time position of the slave shaft; calculating the position deviation between the slave shaft and the master shaft based on the real-time position of the master shaft and the real-time position of the slave shaft; obtaining the running speed of the slave shaft based on the position deviation and the target position; controlling the slave shaft to move at the running speed until it reaches the target position.

[0008] Further, the method for obtaining the real-time position of the master shaft includes: reading the initial position of the master shaft based on the bar code tape; calculating the first running position of the master shaft using the initial position of the master shaft and the running state of the master shaft; verifying the first running position; if the verification error is less than the preset error, the first running position is used as the real-time position of the master shaft.

[0009] Further, the method for verifying the first running position includes: reading the second running position of the master shaft based on the bar code tape; if the difference between the first running position and the second running position is less than the preset error, the first running position is the real-time position of the master shaft.

[0010] Further, the method for obtaining the running speed of the slave shaft includes: V = Kp * e(t) + (Ki * ∫e(t)dt) +(Kd * de(t) / dt); where, V is the running speed, Kp is the proportionality coefficient, e(t) is the preset error, Ki is the integral coefficient, and Kd is the differential coefficient.

[0011] Further, the method for obtaining the running speed of the slave shaft includes: V = Kp ’* (Ki ’* ∫e(t) / dt); where, KP’ = the second running position - the first running position, Ki’ = the electronic gear ratio * integral compensation, and ∫e(t) / dt is the following response.

[0012] Further, the wheel shaft control method further includes: the following response is specifically the position deviation between the slave shaft and the master shaft, where, if the real-time position of the slave shaft is in front of the real-time position of the master shaft, the output is a high following response coefficient, and if the real-time position of the slave shaft is behind the real-time position of the master shaft and the position deviation between the real-time position of the slave shaft and the real-time position of the master shaft is greater than the preset value, the output is a low following response coefficient.

[0013] Further, the wheel shaft control method further includes: if the following response coefficient is high, adjusting the running speed or the running direction of the slave shaft.

[0014] Further, the wheel shaft control method further includes: detecting in real time whether the slave shaft can operate normally, where, the slave shaft includes a plurality of actual wheel shafts; if it is detected that the slave shaft cannot operate normally, reducing the running speed of the slave shaft according to the number of actual wheel shafts that cannot operate normally.

[0015] A wheel axle control system, the wheel axle control system comprising: an input module for obtaining the target position of the slave axle; an operation module for setting a virtual wheel axle as the main axle and an actual wheel axle as the slave axle; a positioning module for obtaining the real-time position of the main axle and the real-time position of the slave axle; a first calculation module for calculating the position deviation between the slave axle and the main axle based on the real-time position of the main axle and the real-time position of the slave axle; a second calculation module for obtaining the running speed of the slave axle based on the position deviation and the target position; and a control module for controlling the slave axle to move at the running speed until it reaches the target position.

[0016] A computer-readable storage medium, on which computer-readable instructions are stored, and when the computer-readable instructions are executed by a processor, each step of the above-mentioned wheel axle control method is implemented.

[0017] Advantageous effects: 1. By setting a servo virtual axis, the wheel axle control method of the present invention uses the servo virtual axis to replace the real axis as the main axis for controlling the wheel axle in the traditional technology, and all other real axes are used as slave axes. Even if any real axis is damaged, the faulty real axis can be directly shielded, and the other real axes can be controlled to run at a reduced speed, so that the operation of the stacker is not affected by the failure of one or several real axes, thereby achieving the purpose of improving the operation stability of the stacker and realizing the effect that the real axis failure does not affect the actual production.

[0018] 2. By setting the real axis operation mode to the synchronous cycle speed mode and the virtual axis to the positioning mode, the wheel axle control method of the present invention calculates the moving speed of the real axis through the positioning of the virtual axis and the position deviation between the virtual axis and the real axis, and precisely controls the operation of the real axis, so that the linear guide device adopting the control method of the present invention shows extremely obvious advantages in terms of positioning accuracy. Description of the drawings

[0019] Figure 1 is a flowchart of the control method of the wheel axle adopted in the embodiment of the present invention; Figure 2 is a schematic structural diagram of the wheel axle control system adopted in the embodiment of the present invention; Figure 3 is a flowchart of the method for obtaining the real-time position of the main axle adopted in the embodiment of the present invention; Figure 4 is a flowchart of the method for verifying the first walking position adopted in the embodiment of the present invention; Figure 5 is a schematic structural diagram of the actual wheel axle of the stacker adopted in the embodiment of the present invention.

[0020] Among them, the above-mentioned attached drawings include the following reference numerals: 1. Actual wheel axle. Specific implementation manner

[0021] In order to enable those skilled in the art to better understand the solution of this application, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the attached drawings in the embodiments of this application. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of this application.

[0022] According to an embodiment of the present invention, a method for controlling a wheel axle is provided. Please refer to Figures 1 to 5 , including: S100 Obtain the target position of the slave axle; S200 Set the virtual wheel axle as the main axle and the actual wheel axle 1 as the slave axle; It should be noted that this embodiment is a full-closed-loop control system. Specifically, for full-closed-loop control, external coding data needs to be converted into ABZ signals that can be recognized by the servo, and connected to the corresponding interface of the servo driver. Its drawback is that the master-slave axle control logic of the existing full-closed-loop system highly depends on the normal operation of the main axle, and its essence is the architecture defect of "strong coupling and weak autonomy". A fault in the main axle will cause the slave axle to get out of control or stop through paths such as signal dependence, power coupling, and failure of the synchronization mechanism, ultimately resulting in the paralysis of the entire system. If the main axle fails, the entire system cannot be used.

[0023] Specifically, the virtual wheel axle is a virtual axle. It is not an actual mechanical motion axle, but an axle simulated by software algorithms in the control system. It usually works in coordination with actual physical axles (such as X, Y, Z axles, etc.) to achieve some special control functions or supplement and expand the physical axles. In this way, by setting a virtual axle to replace the actual wheel axle 1 as the main axle in the wheel axle control method, it is realized that even if any real axle is damaged, the faulty real axle can be directly shielded, and other real axles can be controlled to run at a reduced speed, so that the operation of the stacker is not affected by the failure of one or several real axles, achieving the purpose of improving the operation stability of the stacker.

[0024] S300 Obtain the real-time position of the main axle and the real-time position of the slave axle; The operation of the stacker in this embodiment needs to achieve an error accuracy of ±1mm, which needs to be realized by using an external encoder and a bar code tape that support the SSI protocol. The reader and the module of the PLC that supports SSI protocol communication are combined to achieve the effect of reading the real-time positions of the main axle and the slave axle.

[0025] In this embodiment, the real-time position of the slave shaft is obtained by reading the data of the real-axis bar code strip.

[0026] In the wheel shaft control method of this embodiment, refer to Figure 3 , the method for obtaining the real-time position of the main shaft includes: S310 Read the initial position of the main shaft based on the bar code strip; S320 Calculate the first walking position of the main shaft by using the initial position of the main shaft and the running state of the main shaft; S330 Verify the first walking position; In the wheel shaft control method of this embodiment, the method for verifying the first walking position includes: S331 Read the second walking position of the main shaft based on the bar code strip; S332 If the difference between the first walking position and the second walking position is less than the preset error, the first walking position is the real-time position of the main shaft.

[0027] S340 If the verification error is less than the preset error, the first walking position is used as the real-time position of the main shaft.

[0028] Preferably, the preset error is ±1 mm.

[0029] In specific practice, refer to Figure 5 , since this embodiment performs positioning control on the track instead of on the lead screw and the timing belt, the actual running distance of the virtual shaft is different from the running distance of the motor. Therefore, when the servo is powered on in this embodiment, the bar code strip data is written into the virtual shaft as the initial position of the virtual shaft; when the positioning starts, the bar code strip data is read again and written into the virtual shaft to perform secondary data verification on the position of the virtual shaft. In this way, by reading the bar code strip and calculating the second walking position of the main shaft through the built-in algorithm of the plc control system, the real-time position of the main shaft is verified, and the position deviation between the slave shaft and the main shaft can be calculated more accurately, improving the positioning accuracy of the stacker in this embodiment.

[0030] S400 Calculate the position deviation between the slave shaft and the main shaft based on the real-time position of the main shaft and the real-time position of the slave shaft; S500 Obtain the walking speed of the slave shaft based on the position deviation and the target position; In the wheel shaft control method of this embodiment, the method for obtaining the walking speed of the slave shaft includes: V = Kp * e(t) + (Ki * ∫e(t)dt) + (Kd * de(t) / dt); Wherein, V is the walking speed, Kp is the proportional coefficient, e(t) is the preset error, Ki is the integral coefficient, and Kd is the differential coefficient.

[0031] It should be noted that the above formula includes: (1) Proportional link, that is, the proportional coefficient Kp multiplied by the preset error e(t). The proportional link is used to quickly respond to the error, making the controller output proportional to the error. Specifically, the larger the proportional coefficient Kp, the faster the system response speed, but if the proportional coefficient Kp is too large, it may cause the system to be unstable.

[0032] (2) Integral link, that is, (Ki * ∫e(t)dt). The integral link is used to eliminate the steady-state error of the system. By integrating the error, as time accumulates, the integral term will gradually increase until the steady-state error is zero. Among them, the integral coefficient Ki determines the strength of the integral action. The larger the integral coefficient Ki, the stronger the integral action, but if the integral coefficient Ki is too large, it may cause integral saturation and lead to a slower system response.

[0033] (3) Differential link, that is, Kd * de(t) / dt). The differential link predicts the change trend of the error according to the change rate of the error, and adjusts the system in advance, which can improve the dynamic performance of the system, such as reducing the overshoot and shortening the adjustment time. Specifically, the differential coefficient Kd determines the strength of the differential action. If the differential coefficient Kd is too large, the system may be too sensitive to noise.

[0034] Example 1: According to specific production experience, this example simplifies the influence of the proportional link and the differential link.

[0035] Specifically, the method for obtaining the running speed of the slave axis in this example includes: V = Kp ’* (Ki ’* ∫e(t) / dt) ; where KP’ = the second running position - the first running position, Ki’ = the electronic gear ratio * integral compensation, and ∫e(t) / dt is the following response. In this way, by simplifying the influence of the proportional coefficient and the differential coefficient on the running speed, and through the following response and the error coefficient, the running speed of the slave axis is adjusted in real time, making the speed calculation of the slave axis more in line with the requirements of actual production, and at the same time improving the positioning accuracy of the stacker device in this example.

[0036] In specific practice, the following response needs to be set in advance. If the following response is high, oscillation will occur (that is, the rapid decrease of the slave axis speed or the back-and-forth swing of the vehicle body caused by the slave axis adjusting to the reverse direction of movement), and if the response is low, the positioning cycle time will be prolonged (that is, the virtual axis has run a long distance before the real axis starts to move, resulting in more time for the real axis to reach the target position), affecting the overall speed.

[0037] In the wheel axle control method of this embodiment, the follow-up response specifically refers to the position deviation between the slave axle and the master axle. Among them, if the real-time position of the slave axle is in front of the real-time position of the master axle, the output is a high follow-up response coefficient; if the real-time position of the slave axle is behind the real-time position of the master axle and the real-time position deviation between the slave axle and the master axle is greater than the preset value, the output is a low follow-up response coefficient.

[0038] In specific practice, a low response coefficient indicates that a large position deviation is required for the speed to increase to the predetermined speed (for example, if the specified speed is 3500 mm / s and the acceleration is 1000 mm / s², the position deviation should at least ensure that the speed of the actual axle can reach 3500 mm / s). A low response coefficient means that the real axle speed is represented by 1 / 2at 2 It is difficult to reach the specified speed.

[0039] Preferably, the response coefficient can be adjusted according to the actual equipment status. On the premise that the equipment does not oscillate, the higher the response coefficient, the better, that is, the larger the data setting, the better.

[0040] Embodiment 2: It should be noted that the speed of response reflects the speed of speed increase and the deviation distance between the virtual axle and the real axle.

[0041] In this embodiment, when the deviation distance reaches 100 mm, if the response is fast, the speed can reach 10 mm / s; if the response is slow, the speed reaches 5 mm / s. If the response is too fast, the speed will increase too fast and the actual position will run in front of the virtual axle, causing back-and-forth oscillation. If the response is too slow, it will not affect the system, but only affect the speed increase of the real axle, and the speed increase will become slower and it is difficult to reach the predetermined speed.

[0042] It should be noted that if the follow-up response coefficient is high, the walking speed or the walking direction of the slave axle is adjusted.

[0043] S600 controls the slave axle to move at the walking speed until it reaches the target position.

[0044] The wheel axle control method of this embodiment further includes: Real-time detection of whether the slave axle can operate normally. Among them, the slave axle includes multiple actual wheel axles 1; if it is detected that the slave axle cannot operate normally, the walking speed of the slave axle is reduced according to the number of actual wheel axles 1 that cannot operate normally.

[0045] Embodiment 2: Taking a four-axis stacker as an example, in this embodiment, real-time fault detection is performed on the four actual wheel axles 1 of the four-axis stacker. Whenever a fault is detected in a wheel axle, the running speed of the slave axle is reduced by 30% and a fault warning is issued. In this way, even if one axle of the multi-axis stacker is damaged, the damaged axle can be immediately shielded and the speed can be reduced for operation. It can still complete multi-task handling operations without causing loss of workshop production capacity.

[0046] This embodiment provides a wheel axle control system. Refer to Figure 2 , the wheel axle control system includes: An input module, which is used to obtain the target position of the slave axle; An operation module, which is used to set a virtual wheel axle as the main axle and the actual wheel axle 1 as the slave axle; A positioning module, which is used to obtain the real-time position of the main axle and the real-time position of the slave axle; A first calculation module, which is used to calculate the position deviation between the slave axle and the main axle based on the real-time position of the main axle and the real-time position of the slave axle; A second calculation module, which is used to obtain the running speed of the slave axle based on the position deviation and the target position; A control module, which is used to control the slave axle to move at the running speed until it reaches the target position.

[0047] This embodiment provides a computer-readable storage medium, on which computer-readable instructions are stored. When the computer-readable instructions are executed by a processor, each step of any of the above wheel axle control methods is implemented.

[0048] Embodiments of the present invention may be implemented in the form of a computer program product implemented on one or more storage media (including but not limited to disk memories, CD-ROMs, optical memories, etc.) containing program codes. Computer-readable storage media include permanent and non-permanent, removable and non-removable media, and information storage can be implemented by any method or technology. The information may be computer-readable instructions, data structures, program modules, or other data. Examples of computer-readable storage media include but are not limited to: new types of memories such as phase change memory / resistive random access memory / magnetic random access memory / ferroelectric random access memory (PRAM / RRAM / MRAM / FeRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, compact disc read-only memory (CD-ROM), digital versatile disc (DVD) or other optical storage, magnetic cassette tapes, disk storage or other magnetic storage devices, or any other non-transmission medium that can be used to store information accessible by a computing device.

[0049] It should be noted that the terms "first", "second", etc. in the specification, claims and above-mentioned drawings of this application are used to distinguish similar objects, and do not necessarily have to be used to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0050] Optionally, specific examples in this embodiment may refer to the examples described in the above embodiments, and will not be elaborated herein.

[0051] The serial numbers of the above embodiments of the present application are only for description and do not represent the advantages or disadvantages of the embodiments.

[0052] In the above embodiments of the present application, the descriptions of the respective embodiments have their own emphases. For parts not detailed in a certain embodiment, reference may be made to the relevant descriptions of other embodiments.

[0053] The above is only the preferred embodiment of the present application. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present application, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present application.

Claims

1. A wheel axle control method, characterized in that, Including: Obtain the target position of the slave shaft; Set the virtual wheel shaft as the main shaft and the actual wheel shaft (1) as the slave shaft; Obtain the real-time position of the main shaft and the real-time position of the slave shaft; Based on the real-time position of the main shaft and the real-time position of the slave shaft, calculate the position deviation between the slave shaft and the main shaft; Based on the position deviation and the target position, obtain the traveling speed of the slave shaft; Control the slave shaft to move at the traveling speed until it reaches the target position.

2. The wheel axle control method according to claim 1, characterized in that The method for obtaining the real-time position of the main shaft includes: Read the initial position of the main shaft based on the bar code tape; Calculate the first traveling position of the main shaft by using the initial position of the main shaft and the operating state of the main shaft; Verify the first traveling position; If the verification error is less than the preset error, the first traveling position is used as the real-time position of the main shaft.

3. The wheel axle control method according to claim 2, wherein The method for verifying the first traveling position includes: Read the second traveling position of the main shaft based on the bar code tape; If the difference between the first traveling position and the second traveling position is less than the preset error, the first traveling position is the real-time position of the main shaft.

4. The wheel axle control method according to claim 3, wherein The method for obtaining the traveling speed of the slave shaft includes: V = Kp * e(t) + (Ki * ∫e(t)dt) + (Kd * de(t) / dt); Where, V is the traveling speed, Kp is the proportionality coefficient, e(t) is the preset error, Ki is the integral coefficient, and Kd is the differential coefficient.

5. The wheel axle control method according to claim 4, characterized in that, The method for obtaining the traveling speed of the slave shaft includes: V = Kp ’* (Ki ’* ∫e(t) / dt); Where, KP’ = the second traveling position - the first traveling position, Ki’ = the electronic gear ratio * integral compensation, and ∫e(t) / dt is the following response.

6. The wheel axle control method according to claim 5, characterized in that, The wheel shaft control method further includes: The following response is specifically the position deviation between the slave shaft and the main shaft, where If the real-time position of the slave shaft is in front of the real-time position of the main shaft, the output is that the following response is high; If the real-time position of the slave shaft is behind the real-time position of the main shaft and the deviation between the real-time position of the slave shaft and the real-time position of the main shaft is greater than the preset value, the output is that the following response is low.

7. The wheel axle control method according to claim 6, wherein The wheel shaft control method further includes: If the following response coefficient is high, adjust the traveling speed of the slave shaft or adjust the traveling direction of the slave shaft.

8. The wheel axle control method according to claim 1, characterized in that, The wheel shaft control method further includes: Detect in real time whether the slave shaft can operate normally, where the slave shaft includes a plurality of actual wheel shafts (1); If it is detected that the slave shaft cannot operate normally, reduce the traveling speed of the slave shaft according to the number of the actual wheel shafts (1) that cannot operate normally.

9. A wheel axle control system, characterized in that, The wheel shaft control system includes: An input module, which is used to obtain the target position of the slave shaft; An operation module, which is used to set the virtual wheel shaft as the main shaft and the actual wheel shaft (1) as the slave shaft; A positioning module, which is used to obtain the real-time position of the main shaft and the real-time position of the slave shaft; A first calculation module, which is used to calculate the position deviation between the slave axis and the main axis based on the real-time position of the main axis and the real-time position of the slave axis; A second calculation module, which is used to obtain the running speed of the slave axis based on the position deviation and the target position; A control module, which is used to control the slave axis to move at the running speed until it reaches the target position.

10. A computer-readable storage medium having computer-readable instructions stored thereon, characterized in that, When the computer-readable instructions are executed by a processor, the steps of the wheel axle control method according to any one of claims 1-8 are implemented.

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