Control method and device of lifting system, plc and storage medium

Abstract

The application relates to the field of elevators, and provides a control method and device of an elevator system, a PLC and a computer readable storage medium, the elevator system comprising a sliding frame slidable along a stand column, a cylinder arranged on the sliding frame, a fixed plate arranged along the stand column, the fixed plate being provided with a plurality of anti-falling grooves, and the cylinder being used for being inserted into the anti-falling grooves in an extended state to prevent the sliding frame from sliding; the control method comprises the following steps: in the process of sliding of the sliding frame, obtaining a sliding speed value of the sliding frame fed back by an encoder; determining a sliding speed difference value between the sliding speed value and a given speed value; when the sliding speed difference value is greater than a first preset threshold value, determining a first continuous time length during which the sliding speed difference value is greater than the first preset threshold value; when the first continuous time length is greater than a first preset time length, sending a stop command to a frequency converter; and the cylinder is controlled to be extended so that the cylinder is inserted into the anti-falling grooves, so that the safety during the lifting process of the elevator can be ensured even in the scene of motor brake failure.

Description

Technical Field

[0001] This application relates to the field of elevators, and in particular to a control method, device, PLC, and computer-readable storage medium for an elevator system. Background Technology

[0002] An unexpected descent of a lift can cause unpredictable damage, such as personal injury and property damage if the load on the lift unexpectedly drops. Currently, motor brakes are typically used to prevent the load from falling unexpectedly, ensuring the safety of the lift during ascent and descent. However, if the motor brake fails, the safety of the lift during ascent and descent cannot be guaranteed. Summary of the Invention

[0003] In view of the above problems, embodiments of this application provide a control method, device, PLC and computer-readable storage medium for a lifting system, so as to ensure the safety of the lifting process even in the event of motor brake failure.

[0004] In a first aspect, embodiments of this application provide a control method for a lifting system, wherein the lifting system includes: a base, a top seat, a motor mounted on the top seat, a column located between the base and the top seat, a slide rail slidable along the column, a cylinder mounted on the slide rail, a fixed plate mounted along the height direction of the column, an encoder mounted on the slide rail, a frequency converter connected to the encoder, and a PLC connected to the frequency converter; the fixed plate is provided with a plurality of anti-fall grooves, and the cylinder is used to insert into the anti-fall grooves when in an extended state to prevent the slide rail from sliding; The control method is applied to the PLC and includes: during the sliding process of the carriage, acquiring the sliding speed value of the carriage fed back by the encoder; determining the sliding speed difference between the sliding speed value and a given speed value; when it is determined that the sliding speed difference is greater than a first preset threshold, determining a first duration for which the sliding speed difference is greater than the first preset threshold; when it is determined that the first duration is greater than the first preset duration, sending a stop command to the frequency converter; wherein, the stop command is used to control the motor to stop running; and controlling the cylinder to extend so that the cylinder inserts into the anti-fall device.

[0005] In the technical solution of this application embodiment, when the difference between the sliding speed value of the carriage fed back by the encoder and the given speed value is greater than a preset threshold, and the duration for which the difference between the sliding speed value fed back by the encoder and the given speed value is greater than the first preset threshold is greater than the first preset duration, it indicates that the carriage is in a stall state and the lifting system is in a relatively unsafe state. At this time, after sending a stop command to the frequency converter, the cylinder is directly controlled to extend and insert into the anti-fall groove. This is equivalent to activating two layers of protection for the lifting system. The first layer of protection is to control the motor to stop or the motor to engage the brake (sending a stop command to the frequency converter, which is used to control the motor to stop running; that is, after receiving the stop command, the frequency converter will stop working, and the motor controlled by the frequency converter will stop moving. During the process of the motor stopping, the speed gradually decreases, and the brake control will be automatically activated). The second layer of protection is to control the cylinder to extend and insert into the anti-fall groove, thereby preventing the carriage from sliding. The above two layers of protection can greatly improve the safety of the lifting system. Furthermore, considering the high probability of the first layer of protection failing when the carriage is in a stall state, the dual protection employed in this embodiment ensures that even if the first layer fails, the second layer will still take effect promptly, thus guaranteeing the safety of the lifting system. In other words, even in the event of motor brake failure, the safety of the lifting platform during its lifting process can be guaranteed.

[0006] In some embodiments, the method further includes: sending a stop command to the frequency converter when a first preset condition is met; starting a timer from the time the stop command is sent, and after the timer duration reaches a second preset duration, controlling the cylinder to extend so that the cylinder inserts into the anti-fall groove; wherein the first preset condition includes: receiving the stop command issued by the user side; and / or, the first preset condition includes: determining that the position information of the carriage meets the preset stop condition; the position information is obtained by the encoder positioning the carriage through an encoder ruler, the column includes a first column and a second column, the fixing plate is disposed on the first column, the encoder ruler is disposed on the second column, and the encoder is inserted into the encoder ruler.

[0007] In the technical solution of this application embodiment, when the first preset condition, i.e., the carriage stops normally, is met, it indicates that the carriage is not in a stall state and the lifting system is in a relatively safe state. Therefore, after sending a stop command to the frequency converter, the cylinder is extended to insert into the anti-fall groove after a second preset time interval. After the second preset time interval, the motor speed may have decreased to a relatively low speed. Extending the cylinder to insert into the anti-fall groove at this time helps ensure the relative safety of the lifting system while avoiding significant vibrations caused by the cylinder inserting into the anti-fall groove at high motor speeds. The position of the carriage, i.e., the position of the load placed on the carriage, can be directly obtained through a coded ruler, without needing to use belt motion data. This helps avoid inaccurate load positioning due to belt deformation after long-term use when controlling the carriage movement via belt traction, effectively improving the accuracy of load positioning.

[0008] In some embodiments, the method further includes: when an external fault signal of the frequency converter is detected, sending the stop command to the frequency converter; wherein the external fault signal is a signal output by the frequency converter under a second preset condition, the second preset condition includes: when the speed value of the motor is greater than a second preset threshold, the speed difference between the speed value of the motor and the speed of the second preset threshold is greater than a preset difference, and the second duration for which the speed difference is greater than the preset difference exceeds a third preset duration.

[0009] In the technical solution of this application embodiment, it is equivalent to closed-loop monitoring of the motor speed value. The signal output by the frequency converter under the second preset condition is equivalent to the signal output by the frequency converter when it detects an abnormal motor speed value, which is beneficial for timely control of the motor to stop running when the motor speed value is abnormal. Considering that when the frequency converter malfunctions, it will enter power-on suppression. At this time, the start command sent by the PLC is invalid. A stop command needs to be sent first, and then a start command needs to be sent again for the frequency converter to be ready for power-on. Therefore, after the PLC detects the frequency converter malfunction, it sends a stop command to the frequency converter, which facilitates the subsequent restart of the frequency converter.

[0010] In some embodiments, the method further includes: before the carriage begins to slide, determining whether the cylinder is not in a retracted state; if so, issuing a fault alarm message and sending the stop command to the frequency converter; if not, performing the step of obtaining the sliding speed value of the carriage fed back by the encoder.

[0011] In the technical solution of this application embodiment, before the carriage begins to slide, it is first determined whether the cylinder is not in the retracted state. If the cylinder is determined to be in the retracted state, the step of obtaining the sliding speed value of the carriage is then executed. This ensures that the cylinder can be normally controlled to extend when it is needed, thus ensuring the safety of the lifting system. When it is determined that the cylinder is not in the retracted state, i.e., the cylinder is in the extended state, a fault alarm message is issued and a stop command is sent to the frequency converter. This is beneficial for timely detection and resolution of faults. Furthermore, by sending a stop command to the frequency converter in a timely manner, the motor can be stopped promptly, preventing the motor from driving the carriage to slide when the cylinder is not in the retracted state. This avoids the safety hazards caused by the inability to control the cylinder extension during the sliding process.

[0012] Secondly, embodiments of this application provide a control device for a lifting system, wherein the lifting system includes: a base, a top seat, a motor mounted on the top seat, a column located between the base and the top seat, a slide rail slidable along the column, a cylinder mounted on the slide rail, a fixed plate arranged along the height direction of the column, an encoder mounted on the slide rail, a frequency converter connected to the encoder, and a PLC connected to the frequency converter. The fixed plate is provided with a plurality of anti-fall grooves, and the cylinder is used to insert into the anti-fall grooves when in an extended state to prevent the slide rail from sliding. The control device includes: an acquisition module. The system is used to acquire the sliding speed value of the carriage fed back by the encoder during the sliding process of the carriage; a first determining module is used to determine the sliding speed difference between the sliding speed value and a given speed value; a second determining module is used to determine a first duration for which the sliding speed difference is greater than a first preset threshold; a determining and sending module is used to send a stop command to the frequency converter when it is determined that the sliding speed difference is greater than the first preset threshold and the first duration is greater than the first preset duration; wherein, the stop command is used to control the motor to stop running; and a control module is used to control the cylinder to extend so that the cylinder inserts into the anti-fall groove.

[0013] In some embodiments, the distance between the solid portions of adjacent anti-fall grooves is a preset distance, the number of cylinders is at least 2, and the distance between adjacent cylinders is greater than the preset distance.

[0014] In the technical solution of this application embodiment, by setting at least two cylinders, and the distance between the two cylinders is greater than the distance between the solid parts of two adjacent anti-fall grooves, at least one of the two cylinders can be immediately inserted into the anti-fall groove when the cylinder is extended, thereby controlling the slide to stop sliding immediately, accelerating the speed at which the slide stops sliding, and thus further improving the safety of the lifting system.

[0015] In some embodiments, the control device further includes: a delay control module; the delay control module is configured to send a stop command to the frequency converter when a first preset condition is met, start timing from the time the stop command is sent, and control the cylinder to extend after the timing duration reaches a second preset duration, so that the cylinder inserts into the anti-fall groove; wherein, the first preset condition includes: receiving the stop command issued by the user side; and / or, the first preset condition includes: determining that the position information of the carriage meets the preset stop condition; the position information is obtained by the encoder positioning the carriage through an encoder ruler, the column includes a first column and a second column, the fixing plate is disposed on the first column, the encoder ruler is disposed on the second column, and the encoder is inserted into the encoder ruler.

[0016] In some embodiments, the control device further includes: a detection and transmission module; the detection and transmission module is used to send the stop command to the frequency converter when an external fault signal of the frequency converter is detected; wherein the external fault signal is a signal output by the frequency converter under a second preset condition, the second preset condition includes: when the speed value of the motor is greater than a second preset threshold, the speed difference between the speed value of the motor and the speed of the second preset threshold is greater than a preset difference, and the second duration for which the speed difference is greater than the preset difference exceeds a third preset duration.

[0017] In some embodiments, the control device further includes: a cylinder state determination module; the cylinder state determination module is used to determine whether the cylinder is not in a retracted state before the carriage begins to slide; if so, to issue a fault alarm message and send the stop command to the frequency converter; if not, to perform the step of obtaining the sliding speed value of the carriage fed back by the encoder.

[0018] Thirdly, embodiments of this application provide a programmable logic controller (PLC), comprising: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to perform the control method of the lifting system as described in the first aspect.

[0019] Fourthly, embodiments of this application provide a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the control method for the lifting system as described in the first aspect.

[0020] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the lifting system disclosed in some embodiments of this application;

[0023] Figure 2 This is a flowchart of an implementation of the control method for the lifting system disclosed in some embodiments of this application;

[0024] Figure 3 This is an enlarged schematic diagram of a fixing plate with several anti-fall grooves disclosed in some embodiments of this application;

[0025] Figure 4 This is a flowchart illustrating the implementation of a normal stop control method for a lifting system disclosed in some embodiments of this application;

[0026] Figure 5 This is a flowchart illustrating the implementation of a motor fault monitoring method disclosed in some embodiments of this application;

[0027] Figure 6 This is another implementation flowchart of the control method for the lifting system disclosed in some embodiments of this application;

[0028] Figure 7 This is a schematic diagram of the control device disclosed in some embodiments of this application;

[0029] Figure 8 This is a schematic diagram of the structure of a PLC disclosed in some embodiments of this application.

[0030] The accompanying drawings are not drawn to scale. Detailed Implementation

[0031] The embodiments of this application will be described in further detail below with reference to the accompanying drawings and examples. The detailed description of the following embodiments and the accompanying drawings are used to illustrate the principles of this application by way of example, but should not be used to limit the scope of this application, that is, this application is not limited to the described embodiments.

[0032] In the description of this application, it should be noted that, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," and "outer," etc., indicating orientation or positional relationships, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. Furthermore, the terms "first," "second," and "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. "Vertical" is not vertical in the strict sense, but within the allowable tolerance range. "Parallel" is not parallel in the strict sense, but within the allowable tolerance range.

[0033] The directional terms used in the following description refer to the directions shown in the figures and are not intended to limit the specific structure of this application. It should also be noted in the description of this application that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0034] Currently, judging from market trends, the application scenarios for elevators are becoming increasingly widespread, especially in high-altitude operations such as construction and transportation, where elevators play a vital role. As the application scenarios for elevators continue to expand, the market demand is also constantly increasing.

[0035] The inventors have noted that an unexpected descent of a lift can cause unpredictable harm, such as personal injury and property damage due to the unexpected descent of the load carried by the lift. Currently, to ensure the safety of the lift during the lifting process, a motor brake is used for protection; however, if the motor brake fails, it will be difficult to guarantee the safety of the lift during the lifting process.

[0036] To ensure the safety of elevators during lifting operations, the inventors discovered that the main reason for the difficulty in guaranteeing safety during elevator operations is that the elevator only provides one layer of protection, namely the motor brake. If the motor brake fails, the elevator will be in an unsafe state. If one or more layers of protection could be provided, so that other protection schemes could be used when the motor brake fails, the safety of the elevator during lifting operations could be guaranteed to a certain extent.

[0037] Based on the above considerations, in order to solve the problem that it would be difficult to guarantee the safety of the lifting platform during the lifting process if the motor brake fails, the inventors, after in-depth research, designed a control method for the lifting system by setting up dual protection. By providing dual protection for the lifting platform, specifically the motor brake and cylinder extension protection, even if the motor brake protection fails, the cylinder extension protection can still play a timely protective role, thereby increasing the safety of the lifting platform during the lifting process.

[0038] The lifting system control method disclosed in this application can be used, but is not limited to, to control the operation of elevators in construction, transportation, and other scenarios. In the battery industry, during battery manufacturing, elevators typically use carriages to transport loads such as batteries, cells, and modules to a specific location. The lifting system control method described in this application can be used during this transportation process to ensure the safe operation of the lifting system and the safe transport of the load to the designated location. Specifically, in battery manufacturing processes, the lifting systems in the cell formation and holding chambers, the capacity formation process, and the cross-floor transfer elevators on the conveyor lines can all be controlled using the lifting system control method described in this application to reduce the risk of accidental falls during load lifting and enhance the safety of the lifting system.

[0039] The control method for the lifting system in this embodiment is applied to a programmable logic controller (PLC), and the control method for the lifting system is implemented by the logic inside the PLC.

[0040] According to some embodiments of this application, see [link / reference]. Figure 1 The diagram shown is a structural schematic of a lifting system disclosed in some embodiments of this application. Figure 1 The lifting system includes: a base 101, a top seat 102, a motor 103 mounted on the top seat 102, a column 104 located between the base 101 and the top seat 102, a slide 105 slidable along the column 104, a cylinder 106 mounted on the slide 105, a fixing plate 107 along the height direction of the column 104, an encoder 108 mounted on the slide 105, a frequency converter 109 connected to the encoder 108, and a PLC 110 connected to the frequency converter 109. The fixing plate 107 is provided with several anti-fall grooves 1071, and the cylinder 106 is used to insert into the anti-fall grooves 1071 when in the extended state to prevent the slide 105 from sliding.

[0041] See Figure 2 The diagram shown is a flowchart of one implementation of the control method for a lifting system disclosed in some embodiments of this application. Figure 1 The lifting system shown is described below, and the specific implementation process of the lifting system's control method is as follows:

[0042] Step 201: During the sliding process of the carriage, obtain the sliding speed value of the carriage fed back by the encoder.

[0043] Step 202: Determine the difference between the sliding speed value and the given speed value.

[0044] Step 203: When it is determined that the difference in sliding speed is greater than the first preset threshold, determine the first duration for which the difference in sliding speed is greater than the first preset threshold.

[0045] Step 204: When it is determined that the first duration exceeds the first preset duration, a stop command is sent to the frequency converter. The stop command is used to control the motor to stop running.

[0046] Step 205: Control the cylinder to extend so that the cylinder inserts into the anti-fall groove.

[0047] Figure 1 The motor 103 and the frequency converter 109 are connected by a motor power cable ( Figure 1 The motor 103 is connected via a dashed line (as shown in the diagram), allowing the inverter 109 to control its operating status. The motor 103 can be an AC asynchronous motor, which may include a motor shaft encoder 115, which can be an incremental encoder. The motor shaft encoder 115 can be connected to the high threshold logic (HTL) interface of the inverter 109 via an encoder cable. The motor shaft encoder 115 can send the motor 103's speed value to the HTL interface via the encoder cable, enabling the inverter 109 to obtain the motor 103's speed value and perform closed-loop speed control on the motor 103.

[0048] Inverter 109 and PLC 110 can be connected via a Profinet cable, enabling data exchange between them. In a specific implementation, inverter 109 can be a G120 inverter.

[0049] The carriage 105 is used to place the load. When the motor 103 rotates, it drives the roller 112 to rotate, which in turn drives the belt 114 to move. During the movement, the belt 114 drives the carriage 105 to slide along the column 104, thereby transporting the load placed on the carriage 105 to the designated position.

[0050] An encoder 108 mounted on the carriage 105 is used to acquire the sliding speed value of the carriage 105. Since the carriage 105 is used to place the load, the position of the carriage 105 can also be understood as the position of the load, and the encoder 108 mounted on the carriage 105 can also be understood as the load-side encoder. The encoder 108 can be connected to the synchronous serial interface (SSI) of the frequency converter 109 via an encoder cable. The encoder 108 can send the sliding speed value of the carriage 105 to the SSI interface via the encoder cable, so that the frequency converter 109 can obtain the sliding speed value of the carriage 105.

[0051] The encoder 108 can be a linear measurement encoder, specifically a laser measurement encoder. Using a linear measurement encoder can more accurately obtain the sliding distance of the carriage 105, thereby improving the accuracy of the obtained sliding speed value of the carriage 105.

[0052] The fixing plate 107, which is installed along the height of the column 104, can be a steel plate, and the steel plate can be installed on the column 104 by welding. Figure 1 In the middle, the column 104 includes a first column 1041 and a second column 1042. The steel plate can be installed on the first column 1041 by welding. The plurality of anti-fall grooves 1071 provided on the fixing plate 107 can be a row of holes cut on the fixing plate 107. The shape of this row of holes can be elliptical or circular; however, this embodiment does not specifically limit the shape of the holes. The fixing plate 107 has a hollow part (i.e., the location of the holes) and a solid part. An enlarged schematic diagram of the fixing plate 107 provided with a plurality of anti-fall grooves 1071 can be found in the figure. Figure 3 , Figure 3 Except for the hollow section where the oval hole is located, the rest of the section is solid. Several fall arrestor slots 1071 can be used as follows: Figure 3 The distribution shown is uniform on the fixed plate 107; however, in actual implementation, it is not limited to this.

[0053] Cylinder 106 is mounted on slide 105 and has two states: extended and retracted. When cylinder 106 is in the extended state, it inserts into the anti-fall groove 1071, preventing slide 105 from sliding normally along column 104. When cylinder 106 is in the retracted state, it does not insert into the anti-fall groove 1071, and slide 105 can slide normally along column 104. When slide 105 is sliding normally, cylinder 106 remains in the retracted position. When slide 105 stalls, cylinder 106 immediately inserts into the anti-fall groove 1071 to prevent slide 105 from continuing to slide.

[0054] In one example, see Figure 3The diagram shown is an enlarged schematic of a fixed plate with several anti-fall grooves disclosed in some embodiments of this application. The distance between the solid portions of adjacent anti-fall grooves 1071 is a preset distance, which is d in the diagram. The number of cylinders 106 is at least two, and the distance between adjacent cylinders is greater than the preset distance. By setting at least two cylinders, and the distance between the two cylinders being greater than the distance between the solid portions of two adjacent anti-fall grooves, when the control cylinder extends, at least one of the two cylinders can immediately insert into the anti-fall groove, thereby controlling the slide to stop sliding immediately and accelerating the speed at which the slide stops sliding, thereby further improving the safety of the lifting system.

[0055] In one example, a counterweight 113 can be provided between the first column 1041 and the second column 1042. The counterweight 113 allows the motor 103 to reduce its power without requiring a large torque.

[0056] In one example, a backup motor 116 may also be provided on the top mount 102 so that the backup motor 116 can be used in the event of a failure of motor 103.

[0057] In step 201, during the sliding of the carriage 105, the PLC acquires the sliding speed value of the carriage 105 fed back by the encoder 108. The encoder 108 can acquire the sliding speed value of the carriage 105 in real time during its sliding. After obtaining the sliding speed value, the encoder 108 first sends the sliding speed value of the carriage 105 to the frequency converter 109, which then sends the sliding speed value to the PLC 110, thus enabling the PLC 110 to acquire the sliding speed value of the carriage 105 fed back by the encoder 108. The frequency converter 109 can feed back the sliding speed value of the carriage 105 to the PLC 110 through a status word message.

[0058] In step 202, PLC 110 determines the sliding speed difference between the sliding speed value and the given speed value. The given speed value can be preset and stored in PLC 110 according to actual needs. This given speed value can be a preset desired sliding speed value. Therefore, the sliding speed difference between the sliding speed value and the given speed value can be understood as the difference between the current actual sliding speed value of the carriage 105 and the desired sliding speed value. In this embodiment, the sliding speed difference can specifically be the absolute value of the sliding speed difference.

[0059] In one example, the unit of the given speed value is r / min, and the unit of the sliding speed value is LU / min. To calculate the difference between the given speed value and the sliding speed value, the given speed value and the sliding speed value can be converted to the same unit, for example, the unit of the given speed value can be converted to LU / min. The conversion factor 'a' can be calculated as follows:

[0060] First, calculate the distance the lifting system moves on the load side for one revolution of the roller, h = π * d. Here, d is the roller diameter. When d = 0.32 m, h = π * 0.32 m = 1.005390 m.

[0061] Next, calculate the number of LUs per revolution of the load based on the distance h that the load side moves. Assuming that LU = 1 μm and 1 meter = 1,000,000 LU, then the number of LUs per revolution of the load is m = 1,005,309 LU.

[0062] Finally, based on the rated speed n1 of the motor, the rated speed n2 of the reducer, and the load LU number per revolution m, the conversion coefficient a = (n2 * m) / n1 is determined.

[0063] For example, if n1 = 1455 r / min, n2 = 40 r / min, and m = 1005309 LU, then when the rated speed of the motor is 1455 r / min, the actual sliding speed value fed back by the encoder is as follows:

[0064] 40r / min*1005309LU=40212360LU / min.

[0065] Based on the above, the conversion coefficient a = 40212360 (LU / min) / 1455 (r / min).

[0066] Based on the calculated rotational speed coefficient 'a', the calculated sliding speed difference 'V' is as follows:

[0067] V = Given speed value * a - Sliding speed value fed back by encoder.

[0068] In step 203, when PLC110 determines that the sliding speed difference is greater than a first preset threshold, it determines a first duration for which the sliding speed difference is greater than the first preset threshold. The first preset threshold can be set according to actual needs and stored in PLC110. PLC110 can calculate the sliding speed difference in real time and, when determining that the sliding speed difference is greater than the first preset threshold, accumulate the duration for which the sliding speed difference is greater than the first preset threshold to determine the first duration for which the sliding speed difference is greater than the first preset threshold.

[0069] In step 204, when PLC 110 determines that the first duration exceeds the first preset duration, it sends a stop command to the frequency converter to control the motor to stop running. The first preset duration can be set according to actual needs and stored in PLC 110. During the period when the cumulative sliding speed difference exceeds the first preset threshold, PLC 110 can determine in real time whether the current cumulative duration, i.e., the first duration, is greater than the first preset duration. When it determines that the first duration exceeds the first preset duration, it sends a stop command to the frequency converter 109. After receiving the stop command, the frequency converter 109 stops working, and the motor 103 controlled by the frequency converter 109 stops moving. During the process of the motor 103 stopping, the speed of the motor 103 gradually decreases, and the brake control is automatically activated. The setting of the first preset duration allows the sliding speed difference to exceed the first preset threshold for a short period, which helps to avoid sending unnecessary stop commands to the frequency converter 109 due to occasional fluctuations or related interference in the actual sliding speed value.

[0070] Sending a stop command to the frequency converter to control the motor to stop running can be understood as the first layer of protection in this embodiment, namely, motor braking. The motor braking method is to control the rotating shaft to keep the drum stationary, thereby keeping the carriage stationary.

[0071] In step 205, after sending a stop command to the frequency converter 109, the PLC 110 controls the cylinder 106 to extend, so that the cylinder 106 inserts into the anti-fall groove 1071 to prevent the slide 105 from sliding, so that the slide 105 will not hit the top or fall while carrying the load.

[0072] The extension of the control cylinder to insert into the anti-fall groove can be understood as the second layer of protection in this embodiment. For example, when the motor coupling breaks, the motor is similar to running under no-load, but the slide is in a stalled state. At this moment, the motor brake can no longer keep the slide and counterweight stationary. The actual sliding speed value of the slide fed back to the PLC by the encoder on the slide is inconsistent with the given speed value, and the difference between the sliding speed value and the given speed value will exceed a first preset threshold. The first duration for which the sliding speed difference is greater than the first preset threshold will also be greater than the first preset duration. At this time, the cylinder on the slide immediately inserts into the anti-fall groove to prevent the slide from sliding and prevent accidents from happening.

[0073] In this embodiment, when the difference between the sliding speed value of the carriage fed back by the encoder and the given speed value is greater than a preset threshold, and the duration for which the difference between the sliding speed value fed back by the encoder and the given speed value is greater than the first preset threshold is greater than the first preset duration, it indicates that the carriage is in a stall state, and the lifting system is in a relatively unsafe state. At this time, after sending a stop command to the frequency converter, the cylinder is directly controlled to extend and insert into the anti-fall groove. This is equivalent to activating two layers of protection for the lifting system. The first layer of protection is to control the motor to stop or brake the motor, and the second layer of protection is to control the cylinder to extend and insert into the anti-fall groove, thereby preventing the carriage from sliding. The above two layers of protection can greatly improve the safety of the lifting system. In addition, considering that the first layer of protection is more likely to fail when the carriage is in a stall state, the two layers of protection used in this embodiment can still take effect in time even if the first layer of protection fails, so as to ensure the safety of the lifting system. That is to say, even in the scenario of motor brake failure, the safety of the lifting process can be guaranteed.

[0074] According to some embodiments of this application, the control method for the lifting system further includes a normal stop control method for the lifting system. See also... Figure 4 The diagram shown is an implementation flowchart of a normal stop control method for a lifting system disclosed in some embodiments of this application. The specific implementation steps of this method are as follows:

[0075] Step 401: When the first preset condition is met, send a stop command to the frequency converter.

[0076] The first preset condition includes: receiving a stop command from the user side. And / or, the first preset condition includes: determining that the position information of the carriage meets the preset stop conditions.

[0077] Step 402: Start timing when the stop command is sent. After the timing reaches the second preset duration, control the cylinder to extend so that the cylinder inserts into the anti-fall groove.

[0078] In step 401, when PLC110 determines that the first preset condition is met, it sends a stop command to inverter 109 to stop inverter 109 from working, thereby controlling motor 103 to stop running. The first preset condition can be the condition for carriage 105 to stop normally.

[0079] In one example, the first preset condition includes receiving a stop command from the user side. For instance, when the maintenance personnel of the lifting system (i.e., the user side) want the motor 103 to stop running, they can directly send a stop command to the PLC110 via a terminal device connected to the PLC110, or directly input the stop command on the PLC110's human-machine interface, enabling the PLC110 to receive the stop command from the user side. In a specific implementation, the scenario where the maintenance personnel of the lifting system want the motor 103 to stop running might be: a scenario where the lifting system needs maintenance. To ensure that the carriage 105 does not suddenly fall during maintenance, the maintenance personnel can send a stop command to the PLC110 in the manner mentioned above to control the motor 103 to stop running.

[0080] In one example, the first preset condition includes: determining that the position information of carriage 105 meets preset stopping conditions. See also... Figure 1 The position information is obtained by encoder 108 positioning carriage 105 using encoder ruler 111. The column 104 includes a first column 1041 and a second column 1042. Fixing plate 107 is mounted on the first column 1041, and encoder ruler 111 is mounted on the second column 1042. Encoder 108 is inserted into encoder ruler 111. After obtaining the position information of carriage 105, encoder 108 can send the position information to frequency converter 109, which then sends the position information to PLC 110. PLC 110 then obtains the position information of carriage 105 and determines whether the position information of carriage 105 meets the preset stopping conditions.

[0081] The preset stopping conditions may include: the position information of the carriage 105 is the same as the target position information of the carriage 105. For example, when the lifting system starts running, the PLC 110 receives the target position information where the carriage 105 is expected to stop during this operation. During the sliding process of the carriage 105, if it is determined that the current position information of the carriage 105 is the same as the target position information, it means that the carriage 105 has slid to the target position where the carriage 105 is expected to stop during this operation. At this time, the PLC 110 can determine that the position information of the carriage 105 meets the preset stopping conditions. For example, if the predetermined target position information is the second floor, when the current position information of the carriage 105 is the second floor, that is, when the carriage 105 has slid to the second floor, it can be determined that the position information of the carriage 105 meets the preset stopping conditions.

[0082] In this embodiment, the position information of the carriage 105 can also be understood as the position information of the load placed on the carriage 105. Determining the position information of the carriage 105 in this embodiment is essentially an object-oriented detection, that is, directly detecting the position of the carriage 105 as an object. The encoder 108 is directly set on the load-bearing carriage 105, and the position of the carriage 105, i.e., the position of the load, can be directly obtained through the encoder ruler 111. The load positioning method used in this embodiment does not require the motion data of the belt 114, which helps to avoid the problem of inaccurate positioning caused by deformation and stretching of the belt 114 over a long period of use. Therefore, the load positioning method used in this embodiment can effectively improve the accuracy of load positioning.

[0083] In one example, after receiving the position information of the carriage 105, the PLC110 can display it on the human-machine interface, making it easy to check the actual position of the current load, i.e., the actual position of the carriage 105, at any time.

[0084] In one example, the first preset conditions include: receiving a stop command from the user side and determining that the position information of the carriage 105 meets the preset stop conditions. That is, after receiving the stop command from the user side, PLC 110 will send a stop command to inverter 109, and after determining that the position information of carriage 105 meets the preset stop conditions, PLC 110 will also send a stop command to inverter 109.

[0085] In step 402, PLC 110 starts timing from the time the stop command is sent under the condition of satisfying the first preset condition. After the timing reaches the second preset duration, it controls the cylinder 106 to extend, causing the cylinder 106 to insert into the anti-fall groove 1071. The second preset duration can be set according to actual needs, such as the time required for the motor 103's speed to decrease to a preset speed value. The second preset duration can be greater than or equal to the time required for the motor 103's speed to decrease to the preset speed value.

[0086] In this embodiment, when the first preset condition is met—that is, the carriage stops normally—it indicates that the carriage is not in a stalled state and the lifting system is in a relatively safe state. After sending a stop command to the inverter, the cylinder is extended to insert into the anti-fall groove after a second preset time interval. After this second preset time interval, the motor speed may have decreased to a relatively low speed. Extending the cylinder to insert into the anti-fall groove at this time helps ensure the relative safety of the lifting system while avoiding significant vibrations caused by the cylinder inserting into the anti-fall groove at high motor speeds. The position of the carriage, i.e., the position of the load placed on it, is directly obtained through a coded ruler, eliminating the need for belt motion data. This avoids inaccurate load positioning due to belt deformation after long-term use when controlling carriage movement via belt traction, effectively improving load positioning accuracy.

[0087] According to some embodiments of this application, the control method of the lifting system further includes: when an external fault signal is detected in the frequency converter 109, sending a stop command to the frequency converter 109. The external fault signal is a signal output by the frequency converter 109 under a second preset condition. The second preset condition includes: when the speed value of the motor 103 is greater than a second preset threshold, the speed difference between the speed value of the motor 103 and the second preset threshold is greater than a preset difference, and the second duration for which the speed difference is greater than the preset difference exceeds a third preset duration.

[0088] The second preset threshold can be understood as a given speed value. The second preset threshold, the preset difference, and the third preset duration can all be set and stored in the inverter 109 according to actual needs.

[0089] The motor shaft encoder 115 can acquire the speed value of the motor 103 in real time and send the speed value of the motor 103 to the frequency converter 109. The frequency converter 109 monitors the operating status of the motor 103 based on the speed value of the motor 103. If it is determined that the motor has a fault based on the speed value of the motor 103, it outputs an external fault signal.

[0090] See Figure 5 The diagram shown is a flowchart of a method for monitoring motor faults. The specific implementation process of this method is as follows:

[0091] Step 500: The frequency converter obtains the current speed value of the motor in real time.

[0092] Step 501: The frequency converter determines whether the motor speed is greater than the second preset threshold. If yes, proceed to step 502; otherwise, proceed to step 500.

[0093] Step 502: The frequency converter determines whether the difference between the motor's speed value and the second preset threshold speed value is greater than a preset difference. If yes, proceed to step 503; otherwise, proceed to step 500.

[0094] Step 503: The frequency converter determines the second duration for which the speed difference is greater than the preset difference.

[0095] Step 504: The frequency converter determines whether the second duration exceeds the third preset duration. If yes, proceed to step 505; otherwise, proceed to step 500.

[0096] Step 505: The frequency converter outputs an external fault signal.

[0097] In step 505, the frequency converter 109 outputs an external fault signal, thereby stopping the frequency converter 109 from outputting signals to the motor 103, releasing the brake coil of the motor 103, and putting the motor 103 into a braking state.

[0098] When inverter 109 is running normally, its 8th status word is true. When inverter 109 outputs an external fault signal, its 8th status word changes to false. Thus, PLC 110 can detect the external fault signal output by inverter 109 through the change in the 8th status word. When PLC 110 detects the external fault signal of inverter 109, it sends a stop command to inverter 109.

[0099] In this embodiment, the motor speed is essentially monitored in a closed loop. The signal output by the frequency converter under the second preset condition is equivalent to the signal output when the frequency converter detects an abnormal motor speed, which facilitates timely control to stop the motor when the speed is abnormal. Considering that the frequency converter will enter a power-on suppression state when it malfunctions, a start command sent by the PLC is invalid at this time. A stop command must be sent first, followed by a restart command, before the frequency converter can be ready to power on. Therefore, after the PLC detects a frequency converter fault, it sends a stop command to the frequency converter, facilitating the subsequent restart of the frequency converter.

[0100] According to some embodiments of this application, the control method of the lifting system further includes: determining whether the cylinder 106 is not in a retracted state before the carriage 105 begins to slide. If so, a fault alarm message is issued and a stop command is sent to the frequency converter 109. If not, the step of obtaining the sliding speed value of the carriage 105 fed back by the encoder 108 is performed.

[0101] Before the carriage 105 begins to slide, the PLC 110 determines whether the cylinder 106 is not in a retracted state, i.e., whether the cylinder 106 is in an extended state. A magnetic ring may be provided on the cylinder 106; by detecting the position of the magnetic ring, the state of the cylinder 106—whether it is in an extended or retracted state—can be determined. In other words, in this embodiment, the carriage 105 is only allowed to begin sliding when the state of the cylinder 106 is determined to be in a retracted state, thereby executing the step of obtaining the sliding speed value of the carriage 105 fed back by the encoder 108.

[0102] The fault alarm information issued by PLC110 can be displayed on the human-machine interface or issued in the form of voice to remind the maintenance personnel of the lifting system to deal with the fault in a timely manner.

[0103] In this embodiment, before the carriage begins to slide, it is first determined whether the cylinder is not in the retracted state. If the cylinder is determined to be in the retracted state, the step of obtaining the sliding speed value of the carriage is then executed. This ensures that the cylinder extension can be controlled normally when it is needed to extend, thus ensuring the safety of the lifting system. When it is determined that the cylinder is not in the retracted state (i.e., the cylinder is in the extended state), a fault alarm message is issued and a stop command is sent to the frequency converter. This facilitates timely fault detection and resolution. Furthermore, by sending a stop command to the frequency converter in a timely manner, the motor can be stopped promptly, preventing the motor from driving the carriage to slide when the cylinder is not in the retracted state. This avoids the safety hazard caused by the inability to control the cylinder extension during the carriage's sliding process.

[0104] See Figure 6 The diagram shown is an implementation flowchart of another lifting system control method disclosed in some embodiments of this application. Figure 1 The lifting system shown is described below, and the specific implementation process of the lifting system's control method is as follows:

[0105] Step 601: Determine if the cylinder is not in the retracted state. If so, proceed to step 608; otherwise, proceed to step 602.

[0106] Step 602: Confirm that the lifting system is operational. That is, the PLC can control the lifting system to start operation.

[0107] Step 603: Obtain the sliding speed value of the carriage fed back by the encoder, and determine the sliding speed difference between the sliding speed value and the given speed value.

[0108] Step 604: Determine whether the difference in sliding speed is greater than the first preset threshold. If yes, proceed to step 605; otherwise, proceed to step 602.

[0109] Step 605: Determine whether the first duration for which the sliding speed difference is greater than the first preset threshold is greater than the first preset duration. If yes, proceed to steps 606 and 608; otherwise, proceed to step 602.

[0110] Step 606: Send a stop command to the frequency converter to control the motor to stop running.

[0111] Step 607: Control the extension of the two cylinders so that at least one cylinder is inserted into the fall arrestor slot.

[0112] Step 608: Issue a fault alarm message.

[0113] Step 609: When the first preset condition is met, send a stop command to the frequency converter.

[0114] Step 610: Obtain the timing duration from when the stop command was sent.

[0115] Step 611: Determine whether the timing duration has reached the second preset duration. If yes, proceed to step 607; otherwise, proceed to step 610.

[0116] In the specific implementation, when the judgment result of step 605 is yes, the stall flag can be set to "TRUE". When the first preset condition is met, indicating that the carriage has stopped normally, the stall flag can be set to "FALSE". If the stall flag is "TRUE" when a stop command is sent to the frequency converter, the PLC can immediately control the two cylinders to extend, so that at least one cylinder is inserted into the anti-fall groove. If the stall flag is "FALSE" when a stop command is sent to the frequency converter, the PLC can start a timer to begin counting. When the counting time reaches the second preset time, the PLC will then control the two cylinders to extend, so that at least one cylinder is inserted into the anti-fall groove.

[0117] The steps described above are for clarity only. In practice, they can be combined into one step or broken down into multiple steps, as long as they involve the same logical relationship, they are all within the scope of this patent. Any insignificant modifications or designs added to the algorithm or process, without altering its core design, are also within the scope of this patent.

[0118] According to some embodiments of this application, a control device for a lifting system is provided, see reference. Figure 1 The diagram shown is a structural schematic of a lifting system disclosed in some embodiments of this application. Figure 1The lifting system includes: a base 101, a top seat 102, a motor 103 mounted on the top seat 102, a column 104 located between the base 101 and the top seat 102, a slide 105 slidable along the column 104, a cylinder 106 mounted on the slide 105, a fixing plate 107 mounted along the height direction of the column 104, an encoder 108 mounted on the slide 105, a frequency converter 109 connected to the encoder 108, and a PLC 110 connected to the frequency converter 109. The fixing plate 107 is provided with several anti-fall grooves 1071. The cylinder 106 is used to insert into the anti-fall grooves 1071 when in the extended state to prevent the slide 105 from sliding.

[0119] See Figure 7 The diagram shown is a schematic of the control device for a lifting system disclosed in some embodiments of this application. Figure 7 The control device includes:

[0120] The acquisition module 701 is used to acquire the sliding speed value of the slide 105 fed back by the encoder 108 during the sliding process of the slide 105.

[0121] The first determining module 702 is used to determine the difference in sliding speed between the sliding speed value and the given speed value.

[0122] The second determining module 703 is used to determine a first duration for which the sliding speed difference is greater than the first preset threshold when the sliding speed difference is determined to be greater than the first preset threshold.

[0123] The determination and sending module 704 is used to send a stop command to the frequency converter 109 when it is determined that the first duration is longer than the first preset duration. The stop command is used to control the motor 103 to stop running.

[0124] The control module 705 is used to control the extension of the cylinder 106 so that the cylinder 106 is inserted into the anti-fall groove 1071.

[0125] According to some embodiments of this application, the distance between the solid portions of adjacent anti-fall grooves 1071 is a preset distance, the number of cylinders 106 is at least 2, and the distance between adjacent cylinders 106 is greater than the preset distance.

[0126] See Figure 3 The diagram shown is an enlarged view of a fixing plate with several anti-fall grooves, as disclosed in some embodiments of this application. The preset distance is d in the diagram. (See also...) Figure 1 As shown, there are two cylinders 106. The distance between adjacent cylinders is greater than a preset distance d. In actual implementation, the number of cylinders 106 can be greater than two, depending on actual needs, but this is not a limitation.

[0127] By using at least two cylinders, with the distance between them greater than the distance between the solid sections of two adjacent anti-fall grooves, at least one of the cylinders can immediately insert into the anti-fall groove when the control cylinder extends. This allows the carriage to stop sliding immediately and more quickly, thus further improving the safety of the lifting system. Using two cylinders improves the safety of the lifting system while keeping costs reasonable. Using more than two cylinders increases the success rate of successfully stopping the carriage immediately after extension, significantly enhancing the safety of the lifting system.

[0128] According to some embodiments of this application, the control device further includes a delay control module. The delay control module is used to send a stop command to the frequency converter 109 when a first preset condition is met, start timing from the time the stop command is sent, and after the timing duration reaches a second preset duration, control the cylinder 106 to extend, causing the cylinder 106 to insert into the anti-fall groove 1071. The first preset condition includes: receiving a stop command from the user side. And / or, the first preset condition includes: determining that the position information of the carriage 105 meets the preset stop conditions. The position information is obtained by the encoder 108 positioning the carriage 105 using the encoder ruler 111. The column 104 includes a first column 1041 and a second column 1042, a fixing plate 107 is disposed on the first column 1041, the encoder ruler 111 is disposed on the second column 1042, and the encoder 108 is inserted into the encoder ruler 111.

[0129] According to some embodiments of this application, the control device further includes a detection and transmission module. The detection and transmission module is used to send a stop command to the inverter 109 when an external fault signal is detected. The external fault signal is a signal output by the inverter 109 under second preset conditions. The second preset conditions include: when the rotational speed of the motor 103 is greater than a second preset threshold, the difference between the rotational speed of the motor 103 and the second preset threshold is greater than a preset difference, and the second duration for which the rotational speed difference is greater than the preset difference exceeds a third preset duration.

[0130] According to some embodiments of this application, the control device further includes a cylinder state determination module. The cylinder state determination module is used to determine whether the cylinder 106 is not in a retracted state before the carriage 105 begins to slide. If so, a fault alarm message is issued and a stop command is sent to the frequency converter 109. If not, the step of obtaining the sliding speed value of the carriage 105 fed back by the encoder 108 is performed.

[0131] It is not difficult to see that the embodiments of the control device correspond to the embodiments of the control method described above. The relevant technical details and effects mentioned in the embodiments of the control method described above remain valid in the embodiments of the control device, and will not be repeated here to avoid repetition. Accordingly, the relevant technical details and effects mentioned in the embodiments of the control device can also be applied to the embodiments of the control method described above.

[0132] It is worth mentioning that all modules involved in this embodiment are logical modules. In practical applications, a logical unit can be a physical unit, a part of a physical unit, or a combination of multiple physical units. Furthermore, to highlight the innovative aspects of this invention, this embodiment does not introduce units that are not closely related to solving the technical problems proposed in this application; however, this does not mean that other units are absent in this embodiment.

[0133] According to some embodiments of this application, a PLC is provided, see reference. Figure 8 The diagram shown is a structural schematic of a PLC disclosed in some embodiments of this application. Figure 8 In this PLC, there are at least one processor 801 and a memory 802 communicatively connected to the at least one processor 801. The memory 802 stores instructions executable by the at least one processor 801, which, when executed by the at least one processor 801, enable the at least one processor 801 to perform the control method of the lifting system as described above.

[0134] The memory 802 and processor 801 are connected via a bus, which can include any number of interconnecting buses and bridges. The bus connects various circuits of one or more processors 801 and memory 802 together. The bus can also connect various other circuits, such as peripheral devices, voltage regulators, and power management circuits, which are well known in the art and therefore will not be described further herein. A bus interface provides an interface between the bus and the transceiver. The transceiver can be a single element or multiple elements, such as multiple receivers and transmitters, providing a unit for communicating with various other devices over a transmission medium. Data processed by processor 801 is transmitted over a wireless medium via an antenna, which further receives data and transmits it to processor 801.

[0135] The processor 801 is responsible for managing the bus and general processing, and can also provide various functions, including timing, peripheral interfaces, voltage regulation, power management, and other control functions. The memory 802 can be used to store data used by the processor 801 during operation.

[0136] According to some embodiments of this application, a computer-readable storage medium is provided, storing a computer program. When the computer program is executed by a processor, it implements the above-described method embodiments.

[0137] That is, those skilled in the art will understand that all or part of the steps in the methods of the above embodiments can be implemented by a program instructing related hardware. This program is stored in a storage medium and includes several instructions to cause a device (which may be a microcontroller, chip, etc.) or processor to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as a USB flash drive, a portable hard drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0138] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A control method for a lifting system, wherein, The lifting system includes: a base, a top seat, a motor mounted on the top seat, a column located between the base and the top seat, a slide rail slidable along the column, a cylinder mounted on the slide rail, a fixed plate along the height direction of the column, an encoder mounted on the slide rail, a frequency converter connected to the encoder, and a PLC connected to the frequency converter; the fixed plate is provided with a plurality of anti-fall grooves, and the cylinder is used to insert into the anti-fall grooves when in the extended state to prevent the slide rail from sliding; the control method is applied to the PLC and includes: During the sliding process of the carriage, the sliding speed value of the carriage fed back by the encoder is acquired; Determine the difference in sliding speed between the stated sliding speed value and the given speed value; When it is determined that the sliding speed difference is greater than a first preset threshold, a first duration for which the sliding speed difference is greater than the first preset threshold is determined; When it is determined that the first duration exceeds the first preset duration, a stop command is sent to the frequency converter; wherein, the stop command is used to control the motor to stop running; Control the cylinder to extend so that the cylinder inserts into the anti-fall groove; The distance between the solid portions of adjacent fall arrestor slots is a preset distance, the number of cylinders is at least 2, and the distance between adjacent cylinders is greater than the preset distance.

2. The control method for the lifting system according to claim 1, wherein, The method further includes: When the first preset condition is met, the stop command is sent to the frequency converter; The timing begins when the stop command is sent, and after the timing reaches a second preset duration, the cylinder is controlled to extend, causing the cylinder to insert into the anti-fall groove; The first preset condition includes: receiving the stop command issued by the user; and / or, The first preset condition includes: determining that the position information of the carriage meets the preset stopping condition; the position information is obtained by the encoder positioning the carriage through the encoder ruler, the column includes a first column and a second column, the fixing plate is set on the first column, the encoder ruler is set on the second column, and the encoder is inserted into the encoder ruler.

3. The control method for the lifting system according to claim 1 or 2, wherein, The method further includes: When an external fault signal is detected in the frequency converter, the stop command is sent to the frequency converter; The external fault signal is a signal output by the frequency converter under a second preset condition. The second preset condition includes: when the speed of the motor is greater than a second preset threshold, the speed difference between the speed of the motor and the second preset threshold is greater than a preset difference, and the second duration for which the speed difference is greater than the preset difference exceeds a third preset duration.

4. The control method for the lifting system according to any one of claims 1 to 3, wherein, The method further includes: Before the carriage begins to slide, it is determined whether the cylinder is not in the retracted state; If so, a fault alarm message is issued and the stop command is sent to the frequency converter; If not, then proceed with the step of obtaining the sliding speed value of the carriage fed back by the encoder.

5. A control device for a lifting system, wherein, The lifting system includes: a base, a top seat, a motor mounted on the top seat, a column located between the base and the top seat, a slide rail slidable along the column, a cylinder mounted on the slide rail, a fixed plate along the height direction of the column, an encoder mounted on the slide rail, a frequency converter connected to the encoder, and a PLC connected to the frequency converter. The fixed plate has several anti-fall grooves, and the cylinder is used to insert into the anti-fall grooves when in the extended state to prevent the slide rail from sliding. The control device includes: The acquisition module is used to acquire the sliding speed value of the carriage fed back by the encoder during the sliding process of the carriage; The first determining module is used to determine the sliding speed difference between the sliding speed value and the given speed value; The second determining module is used to determine a first duration for which the sliding speed difference is greater than the first preset threshold when it is determined that the sliding speed difference is greater than the first preset threshold. The determination and sending module is used to send a stop command to the frequency converter when it is determined that the first duration is greater than a first preset duration; wherein the stop command is used to control the motor to stop running; The control module is used to control the extension of the cylinder so that the cylinder inserts into the anti-fall groove; The distance between the solid portions of adjacent fall arrestor slots is a preset distance, the number of cylinders is at least 2, and the distance between adjacent cylinders is greater than the preset distance.

6. The control device for the lifting system according to claim 5, wherein, The control The device also includes: a delay control module; The delay control module is used to send a stop command to the frequency converter when a first preset condition is met, start timing from the time the stop command is sent, and control the cylinder to extend after the timing reaches a second preset duration, so that the cylinder inserts into the anti-fall groove; The first preset condition includes: receiving the stop command issued by the user; and / or, The first preset condition includes: determining that the position information of the carriage meets the preset stopping condition; the position information is obtained by the encoder positioning the carriage through the encoder ruler, the column includes a first column and a second column, the fixing plate is set on the first column, the encoder ruler is set on the second column, and the encoder is inserted into the encoder ruler.

7. The control device for the lifting system according to any one of claims 5 to 6, wherein, The control device further includes: a detection and transmission module; The detection and transmission module is used to send the stop command to the frequency converter when an external fault signal of the frequency converter is detected; The external fault signal is a signal output by the frequency converter under a second preset condition. The second preset condition includes: when the speed of the motor is greater than a second preset threshold, the speed difference between the speed of the motor and the second preset threshold is greater than a preset difference, and the second duration for which the speed difference is greater than the preset difference exceeds a third preset duration.

8. The control device for the lifting system according to any one of claims 5 to 7, wherein, The control device further includes: a cylinder status determination module; The cylinder state determination module is used to determine whether the cylinder is not in a retracted state before the carriage starts to slide; if so, it issues a fault alarm message and sends the stop command to the frequency converter; if not, it executes the step of obtaining the sliding speed value of the carriage fed back by the encoder.

9. A programmable logic controller (PLC), comprising: At least one processor; and, A memory communicatively connected to the at least one processor; wherein, The memory stores instructions that can be executed by the at least one processor to enable the at least one processor to perform the control method of the lifting system as described in any one of claims 1 to 4.

10. A computer-readable storage medium storing a computer program that, when executed by a processor, implements the control method of the lifting system according to any one of claims 1 to 4.

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