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] This invention relates to the field of linear guide technology, and specifically to a wheel axle control method and system. Background Technology

[0002] Stacker cranes, as core equipment in modern logistics warehousing systems, are widely used for cargo storage, retrieval, handling, and efficient management of automated warehouses. The stability and reliability of their traveling mechanism directly determine the stacker crane's operating efficiency and the overall continuity of system operation. In existing technologies, the wheel axle drive system of stacker cranes typically adopts a control mode of coordinated operation between the master shaft and the driven shaft. That is, by setting up one master shaft (driving wheel axle) and at least one driven shaft (driven wheel axle), the synchronous drive and control of multiple wheels is achieved. The master shaft, as the core power output unit, is responsible for receiving control commands and driving the driven shaft to follow the movement, thereby ensuring the consistency of the rotational speed and steering of each wheel.

[0003] However, existing control methods have significant drawbacks: since the main shaft bears the core control and power transmission functions, if it malfunctions due to mechanical failure (such as bearing damage or transmission gear failure) or electrical failure (such as motor overload or encoder malfunction), the driven shaft will be unable to operate independently, leading to the paralysis of the entire stacker crane's traveling mechanism. Such failures not only cause equipment downtime and affect warehousing efficiency, but may also cause cargo displacement or mechanical structural impact due to emergency braking, increasing maintenance costs and safety risks. Furthermore, after a main shaft failure, the driven shaft lacks autonomous operation capability, requiring manual intervention or a complete system shutdown for maintenance during the recovery process, which fails to meet the high availability and rapid fault recovery requirements of modern logistics systems.

[0004] Therefore, there is an urgent need for a new wheel axle drive control method and system that can improve the system's fault tolerance and fault isolation performance while ensuring multi-axis synchronization accuracy, thereby avoiding the overall interruption of stacker crane operation due to main shaft failure and affecting the stable operation of stacker crane.

[0005] Therefore, existing technologies need further development. Summary of the Invention

[0006] The purpose of this invention is to overcome the above-mentioned technical deficiencies and provide a wheel axle control method and system to solve the technical problem of the overall operation interruption of the stacker crane 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 solution: a wheel axle control method is provided, comprising: acquiring the target position of the slave axle; setting a virtual wheel axle as the master axle and an actual wheel axle as the slave axle; acquiring the real-time position of the master axle and the real-time position of the slave axle; calculating the position deviation between the slave axle and the master axle based on the real-time position of the master axle and the real-time position of the slave axle; calculating the walking speed of the slave axle based on the position deviation; and controlling the slave axle to move according to the walking speed until it reaches the target position.

[0008] Furthermore, the method for obtaining the real-time position of the spindle includes: reading the initial position of the spindle based on the barcode strip; calculating the first travel position of the spindle using the initial position and the operating state of the spindle; verifying the first travel position; if the verification error is less than a preset error, the first travel position is taken as the real-time position of the spindle.

[0009] Furthermore, the method for verifying the first walking position includes: reading the second walking position of the main shaft based on the barcode strip; if the difference between the first walking position and the second walking position is less than a preset error, then the first walking position is the real-time position of the main shaft.

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

[0011] Furthermore, the method for obtaining the travel speed of the slave axis includes: V = Kp' * (Ki' * ∫e(t) / dt) / Kd; where Kp' = second travel position - first travel position, Ki' = electronic gear ratio * integral compensation, ∫e(t) / dt is the following response, and Kd is the response time.

[0012] Furthermore, the wheel axle control method also includes: the following response specifically refers to the position deviation between the slave axle and the master axle, wherein 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 following 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 a preset value, the output is a low following response coefficient.

[0013] Furthermore, the wheel axle control method also includes: if the following response coefficient is high, adjusting the travel speed of the driven axle or adjusting the response time of the driven axle.

[0014] Furthermore, the wheel axle control method also includes: real-time detection of whether the slave axle can operate normally, wherein the slave axle includes multiple actual wheel axles; if an actual wheel axle is detected to be not operating normally, a corresponding removal reminder is issued according to the position of the actual wheel axle that is not operating normally; and the travel speed of the slave axle is adjusted based on the number of actual wheel axles that are not operating normally.

[0015] A wheel axle control system includes: an input module for acquiring the target position of a driven axle; an operation module for setting a virtual wheel axle as the master axle and an actual wheel axle as the driven axle; a positioning module for acquiring the real-time position of the master axle and the real-time position of the driven axle; a first calculation module for calculating the positional deviation between the driven axle and the master axle based on the real-time positions of the master axle and the driven axle; a second calculation module for calculating the walking speed of the driven axle based on the positional deviation; and a control module for controlling the driven axle to move at the walking speed until it reaches the target position.

[0016] A computer-readable storage medium storing computer-readable instructions, which, when executed by a processor, implement the various steps of the aforementioned wheel axle control method.

[0017] Beneficial effects:

[0018] 1. The wheel axle control method of the present invention sets up a servo virtual axis, which replaces the traditional technology of using the real axle as the master axis for wheel axle control, and all other real axles as slave axes. Even if any real axle is damaged, the other real axles can be controlled to run at reduced speed by directly shielding the faulty real axle. This makes the operation of the stacker crane unaffected by the failure of one or several real axles, thereby improving the stability of stacker crane operation and achieving the effect that the failure of real axles does not affect actual production.

[0019] 2. The wheel axle control method of the present invention sets the real axle running mode to synchronous periodic speed mode and the virtual axle to positioning mode. The moving speed of the real axle is calculated by the positioning of the virtual axle and the positional deviation between the virtual axle and the real axle, so as to accurately control the operation of the real axle. This makes the linear guide rail device using the control method of the present invention exhibit a very obvious advantage in positioning accuracy. Attached Figure Description

[0020] Figure 1 This is a flowchart of the wheel axle control method used in an embodiment of the present invention;

[0021] Figure 2 This is a schematic diagram of the wheel axle control system used in an embodiment of the present invention;

[0022] Figure 3This is a flowchart of the method for obtaining the real-time position of the spindle used in an embodiment of the present invention;

[0023] Figure 4 This is a flowchart of the method for verifying the first walking position used in an embodiment of the present invention;

[0024] Figure 5 This is a schematic diagram of the actual wheel axle structure of the stacker crane used in an embodiment of the present invention.

[0025] The above figures include the following reference numerals:

[0026] 1. Actual wheel axle. Detailed Implementation

[0027] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0028] According to an embodiment of the present invention, a wheel axle control method is provided; please refer to [link / reference]. Figures 1 to 5 ,include:

[0029] S100 obtains the target position of the slave axis;

[0030] S200 sets the virtual wheel axle as the master axle and the actual wheel axle 1 as the slave axle;

[0031] It should be noted that this embodiment is a fully closed-loop control system. Specifically, fully closed-loop control requires converting externally encoded data into ABZ signals that the servo can recognize and connecting to the corresponding interface of the servo driver. Its drawback is that the master-slave axis control logic of existing fully closed-loop systems is highly dependent on the normal operation of the master spindle, which is essentially a "strongly coupled, weakly autonomous" architectural flaw. A master spindle failure can cause the slave axis to malfunction or stop through signal dependence, dynamic coupling, or synchronization mechanism failure, ultimately leading to the overall system paralysis. If the master spindle fails, the entire system will be unusable.

[0032] Specifically, a virtual wheel axle is a virtual axle that is not an actual mechanical axle, but rather an axle simulated by software algorithms in the control system. It typically works in conjunction with actual physical axes (such as X, Y, and Z axes) to implement specific control functions or supplement and extend the physical axes. In this way, by setting a virtual axle to replace the actual wheel axle 1 as the main axis in the wheel axle control method, even if any real axle fails, the faulty real axle can be directly shielded, and other real axles can be controlled to slow down. This ensures that the stacker crane's operation is not affected by the failure of one or more real axles, thus improving the stability of the stacker crane's operation.

[0033] The S300 acquires the real-time position of the spindle and the real-time position of the slave axis.

[0034] In this embodiment, the stacker crane operation needs to achieve an error accuracy of ±1mm, which requires the use of an external encoder and barcode tape that support the SSI protocol. The barcode reader and the PLC module that supports SSI protocol communication are combined to achieve the effect of reading the real-time position of the main shaft and the slave shaft.

[0035] In this embodiment, the real-time position of the axis is obtained by reading the data from the real axis barcode strip.

[0036] In the wheel axle control method of this embodiment, see... Figure 3 Methods for obtaining the real-time position of the spindle include:

[0037] The S310 reads the initial position of the spindle based on the barcode strip;

[0038] S320 calculates the first travel position of the spindle using the initial position and the operating state of the spindle;

[0039] S330 verifies the first walking position;

[0040] In the wheel axle control method of this embodiment, the method for verifying the first travel position includes:

[0041] S331 reads the second travel position of the spindle based on the barcode strip;

[0042] S332 If the difference between the first walking position and the second walking position is less than the preset error, then the first walking position is the real-time position of the main axis.

[0043] If the verification error is less than the preset error, the first walking position is taken as the real-time position of the spindle.

[0044] Preferably, the preset error is ±1mm.

[0045] In practical application, see Figure 5Because this embodiment performs positioning control on the track rather than on the lead screw and timing belt, the actual running distance of the virtual axis differs from the running distance of the motor. Therefore, in this embodiment, when the servo is powered on, barcode tape data is written to the virtual axis as its initial position. When positioning begins, the barcode tape data is read again and written to the virtual axis for secondary data verification of the virtual axis's position. In this way, by using barcode tape reading and the PLC control system's built-in algorithm to calculate the second travel position of the main shaft and verifying the real-time position of the main shaft, the positional deviation between the slave axis and the main shaft can be calculated more accurately, improving the positioning accuracy of the stacker crane in this embodiment.

[0046] The S400 calculates the positional deviation between the slave and master axes based on the real-time positions of the master and slave axes.

[0047] The S500 calculates the travel speed of the axle based on the position deviation;

[0048] In the wheel axle control method of this embodiment, the method for calculating the travel speed of the driven axle includes:

[0049] V=Kp*e(t)+(Ki*∫e(t)dt)+(Kd*de(t) / dt);

[0050] Where V is the travel speed of the slave axis, Kp is the proportional coefficient, e(t) is the preset error, Ki is the integral coefficient, and Kd is the response time.

[0051] It should be noted that the above formula includes:

[0052] (1) Proportional element, that is, proportional coefficient Kp multiplied by preset error e(t). The proportional environment is used to quickly respond to the error, so that the controller output is proportional to the error. Specifically, the larger the proportional coefficient Kp, the faster the system response speed, but too large a proportional coefficient Kp may lead to system instability.

[0053] (2) Integral term, i.e. (Ki*∫e(t)dt), is used to eliminate the steady-state error of the system. By integrating the error, the integral term will gradually increase over time until the steady-state error is zero. The integral coefficient Ki determines the strength of the integral effect. The larger the integral coefficient Ki is, the stronger the integral effect. However, if the integral coefficient Ki is too large, it may cause integral saturation, which will slow down the system response.

[0054] (3) Differential element, i.e. Kd*de(t) / dt), the differential element predicts the trend of error change based on the rate of change of error and adjusts the system in advance, which can improve the dynamic performance of the system, such as reducing 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.

[0055] Example 1:

[0056] Based on specific production experience, this embodiment simplifies the impact of the proportioning process.

[0057] Specifically, in this embodiment, the method for obtaining the travel speed of the slave axis includes:

[0058] V=Kp'*(Ki'*∫e(t) / dt) / Kd;

[0059] Where KP' = second traveling position - first traveling position, Ki' = electronic gear ratio * integral compensation, ∫e(t) / dt is the following response, and Kd is the response time. The response time is obtained by working backward from the maximum following distance required, which requires both the virtual axis and the slave axis to reach their maximum set speed. Specifically, the following distance is the distance between the virtual axis and the real axis, obtained in this embodiment by reading barcode data. This simplifies the influence of the proportional and differential coefficients on the traveling speed, and allows for real-time adjustment of the slave axis's traveling speed using the following response and error coefficient, making the slave axis speed calculation more aligned with actual production needs and improving the positioning accuracy of the stacker crane device in this embodiment. In practice, the following response needs to be set in advance. A high following response will cause oscillations (i.e., the slave axis speed rapidly decreases or the slave axis adjusts to the opposite direction, causing the vehicle body to swing back and forth), while a low response will prolong the positioning cycle time (i.e., the virtual axis has already traveled a long distance before the real axis begins to move, causing the real axis to need more time to reach the target position), affecting the overall speed.

[0060] In the wheel axle control method of this embodiment, the following response is specifically the position deviation between the slave axle and the master axle. 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 following 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 a preset value, the output is a low following response coefficient.

[0061] In practice, a low response coefficient indicates that a significant positional deviation is required to reach the predetermined speed (e.g., if the specified speed is 3500 mm / s and the acceleration is 1000 mm / s, the positional deviation must at least ensure that the actual shaft speed reaches 3500 mm / s). A low response coefficient also indicates that the actual shaft speed is within 1 / 2 at. 2 It is difficult to reach the specified speed.

[0062] Preferably, the response coefficient can be adjusted according to the actual equipment status. Provided that the equipment does not oscillate, the higher the response coefficient, the better; that is, the larger the data setting, the better.

[0063] Example 2:

[0064] It should be noted that response speed reflects the rate of speed increase and the deviation distance between the imaginary axis and the real axis.

[0065] In this embodiment, when the deviation distance reaches 100mm, the speed can reach 10mm / s if the response is fast, and 5mm / s if the response is slow. If the response is too fast, the speed will increase too quickly and the actual position will run in front of the imaginary axis, causing back and forth oscillation. If the response is too slow, it will not have any impact on the system, but it will affect the speed increase of the real axis, making it difficult to reach the predetermined speed.

[0066] It should be noted that if the follower response coefficient is high, the travel speed of the slave axis or the travel direction of the slave axis should be adjusted.

[0067] Example 3:

[0068] In practice, the method for obtaining the travel speed of the shaft is shown in the table below:

[0069] Table 1 shows the calculation of the trailing axis speed using the virtual axis position and barcode strip data.

[0070]

[0071] The calculation data in the table shows that the smaller the response time, the shorter the following distance, and the faster the walking speed will be for the same distance.

[0072] Table 2 shows the calculation of the travel speed of the axle using position deviation.

[0073]

[0074]

[0075] The S600 controls the slave axis to move at the travel speed until it reaches the target position.

[0076] The wheel axle control method in this embodiment also includes:

[0077] The system can detect in real time whether the slave axle is operating normally. The slave axle includes multiple actual wheel axles 1. If the slave axle is detected to be not operating normally, the travel speed of the slave axle is reduced according to the number of actual wheel axles 1 that are not operating normally.

[0078] Example 4:

[0079] Taking a four-axis stacker crane as an example, this embodiment performs real-time fault detection on the four actual wheel axles 1 of the four-axis stacker crane. Whenever a fault is detected in a wheel axle, the running speed of the axle is reduced by 30% and a fault warning is issued. In this way, even if a single axle of the multi-axis stacker crane is damaged, the damaged axle can be immediately shielded and the speed can be reduced. The multi-task handling operation can still be completed without causing a loss of workshop production capacity.

[0080] This embodiment provides a wheel axle control system, see [link / reference] Figure 2 The wheel axle control system includes:

[0081] The input module is used to obtain the target position of the slave axis;

[0082] The operation module is used to set the virtual wheel axle as the master axle and the actual wheel axle 1 as the slave axle.

[0083] The positioning module is used to obtain the real-time position of the main spindle and the real-time position of the slave axis.

[0084] The first calculation module is used to calculate the positional deviation between the slave axis and the master axis based on the real-time position of the master axis and the real-time position of the slave axis.

[0085] The second calculation module is used to obtain the walking speed of the axis based on the position deviation and the target position.

[0086] The control module is used to control the movement of the slave axis at the walking speed until it reaches the target position.

[0087] This embodiment provides a computer-readable storage medium storing computer-readable instructions, which, when executed by a processor, implement the steps of any of the wheel axle control methods described above.

[0088] This invention can take the form of a computer program product implemented on one or more storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing program code. 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. Information can be computer-readable instructions, data structures, program modules, or other data. Examples of computer-readable storage media include, but are not limited to: novel memories such as phase-change memory / resistive random access memory / magnetic memory / ferroelectric 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, read-only optical disc read-only memory (CD-ROM), digital versatile optical disc (DVD) or other optical storage, magnetic tape, disk storage or other magnetic storage devices, or any other non-transfer medium that can be used to store information accessible by a computing device.

[0089] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0090] Optionally, specific examples in this embodiment can refer to the examples described in the above embodiments, and will not be repeated here.

[0091] The sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0092] In the above embodiments of this application, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0093] The above description is only a preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A wheel axle control method, characterized in that, include: Obtain the target position from the axis; Set the virtual wheel axle as the master axle and the actual wheel axle (1) as the slave axle; Obtain the real-time position of the main spindle and the real-time position of the slave spindle; Based on the real-time position of the master axis and the real-time position of the slave axis, calculate the positional deviation between the slave axis and the master axis; Based on the positional deviation, the travel speed of the slave axis is calculated; The slave axis is controlled to move at the travel 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 spindle includes: The initial position of the spindle is read based on the barcode strip; The first travel position of the spindle is calculated using the initial position of the spindle and the operating state of the spindle; The first walking position is verified; If the verification error is less than the preset error, then the first walking position is taken as the real-time position of the main shaft.

3. The wheel axle control method according to claim 2, characterized in that, The method for verifying the first walking position includes: The second travel position of the main shaft is read based on the barcode strip; If the difference between the first walking position and the second walking position is less than a preset error, then the first walking position is the real-time position of the spindle.

4. The wheel axle control method according to claim 3, characterized in that, The method for obtaining the travel speed of the slave axis includes: V=Kp*e(t)+(Ki*∫e(t)dt)+(Kd*de(t) / dt); Where V is the travel speed of the slave axis, Kp is the proportional 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 travel speed of the slave axis includes: V=Kp'*(Ki'*∫e(t) / dt) / Kd; Where KP' = second travel position - first travel position, Ki' = electronic gear ratio * integral compensation, ∫e(t) / dt is the following response, and Kd is the response time.

6. The wheel axle control method according to claim 5, characterized in that, The wheel axle control method further includes: the following response specifically being the positional deviation between the slave axle and the master axle, wherein... If the real-time position of the slave axis is ahead of the real-time position of the master axis, the output is a high follow response. If the real-time position of the slave axis is behind the real-time position of the master axis and the deviation between the real-time position of the slave axis and the real-time position of the master axis is greater than a preset value, then the output is a low follow-up response.

7. The wheel axle control method according to claim 6, characterized in that, The wheel axle control method further includes: if the following response coefficient is high, adjusting the walking speed of the slave axle or adjusting the response time of the slave axle.

8. The wheel axle control method according to claim 1, characterized in that, The wheel axle control method further includes: Real-time detection of whether the slave axle can operate normally, wherein the slave axle includes multiple actual wheel axles (1); If the actual wheel axle (1) is detected to be not operating normally, a corresponding removal reminder will be issued according to the location of the actual wheel axle (1) that is not operating normally; The travel speed of the slave axle is adjusted based on the number of actual wheel axles (1) that are not functioning properly.

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

10. A computer-readable storage medium storing computer-readable instructions thereon, characterized in that, When the computer-readable instructions are executed by a processor, they implement the steps of the wheel axle control method as described in any one of claims 1-8.

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