Stacker based on servo motor anti-sway control and control method

Abstract

The application discloses a kind of based on servo motor anti-shake control's stacking machine and control method, and the application relates to warehouse logistics technical field, including front upright, rear upright, servo motor anti-shake component, front guide wheel, rear guide wheel, anti-collision block, upper beam weldment, rope pulley and inclination sensor.The application adopts active servo damping technology, can real-time offset the inertia of stacking machine acceleration and deceleration and start-stop phase swing, eliminate the inertia swing of crossbeam and upright from root, avoid fork alignment deviation, improve positioning accuracy, without waiting for swing natural attenuation can be stable stop, compress single trip operation time consumption, improve operation flow efficiency, adapt to high turnover warehouse demand, while offsetting alternating load, reduce structural fatigue loss, prolong the service life of whole machine, reduce operation and maintenance cost, the damping wheel pressure of servo motor anti-shake component is adjustable, adapt to multiple scenarios, and universality is strong, and higher operating reliability.

Description

Technical Field

[0001] This invention relates to the field of warehousing and logistics technology, specifically to a stacker crane and control method based on servo motor anti-sway control. Background Technology

[0002] Stacker cranes are automated logistics equipment that, under the control of WCS (Warehouse Control System) and WMS (Warehouse Management System), automatically perform outbound and inbound operations on unit goods on the shelves on both sides of the aisle, thereby improving warehouse operation efficiency. As manufacturing and logistics companies continue to expand, the number and size of warehouses are also increasing. However, manual operation can no longer meet the demand for fast and efficient logistics. Against this backdrop, stacker cranes have been widely used and promoted, and have gradually become an indispensable part of the logistics industry.

[0003] When a traditional stacker crane is in motion, the welded upper beam sways due to inertia, affecting the working accuracy. In order to suppress the swaying, the stopping and stabilization time is increased, which will affect the overall working efficiency of the stacker crane. Therefore, it is necessary to develop a stacker crane upper beam anti-swaying device that can suppress inertial swaying. Summary of the Invention

[0004] The purpose of this invention is to provide a stacker crane and control method based on servo motor anti-sway control. When the servo motor is powered on, corresponding parameters are set to maintain torque at zero speed. When the upper beam welded component rotates the motor shaft, the motor senses this force and immediately outputs a reverse torque equal to the set value to resist it. When the external force exceeds the set torque and continues to act, the motor will rotate slowly within the set speed without jamming. The servo motor is installed on the upper beam welded component, and the roller coaxially connected to the servo motor presses tightly against the overhead rail. When the stacker crane brakes, the servo motor acts as an anti-sway damper, and the anti-sway effect is fed back through an tilt sensor. The servo motor is then controlled again to take anti-sway control measures, effectively suppressing the swaying of the upper beam when the stacker crane brakes, thus solving the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] In a first aspect, the present invention provides a stacker crane based on servo motor anti-sway control, comprising:

[0007] The front column and the rear column are equipped with upper beam welded parts, and the front column, the rear column and the upper beam welded parts together form the upper frame of the stacker crane;

[0008] A front guide wheel and a rear guide wheel are respectively mounted on the end plates at the front and rear ends of the upper beam weldment;

[0009] Two anti-collision blocks are fixed to the outer end faces of the front guide wheel and the rear guide wheel respectively by bolts;

[0010] Two sets of rope-winding pulleys are fixed to the side of the upper beam welded part through bearing seats. They cooperate with the wire rope to realize the lifting and lowering transmission of the forks.

[0011] An inclination sensor is installed on the front column. The inclination sensor is used to detect the inclination of the column when the stacker crane shakes, so as to transmit a signal to the PLC to indicate the suppression of the stacker crane shaking.

[0012] A servo motor anti-sway component is installed on the upper beam weld. The servo motor anti-sway component is used to calculate the reverse damping torque to counteract the swaying and apply resistance in the opposite direction of the swaying to deal with the swaying of the column during the acceleration, deceleration and start-stop of the stacker crane.

[0013] Optionally, the servo motor anti-sway component includes:

[0014] A fixed bracket is installed on the side of the upper beam weldment. The fixed bracket has two shaft holes, through which the swing shaft passes. Swing bracket one and swing bracket two are respectively fitted onto the swing shaft.

[0015] An adjusting screw is provided, with a rocker arm threaded to one end. A rocker arm shaft is rotatably connected to the rocker arm, which is rotatably connected to the second swing bracket. The other end of the adjusting screw passes through the first swing bracket. A compression spring is sleeved on the outside of the adjusting screw, with one end of the compression spring abutting against the side of the first swing bracket, and the other end of the compression spring being locked by an adjusting nut.

[0016] A servo motor, the flange of which is installed below the swing bracket, the servo motor is connected to a damping wheel on one side via a main shaft, and the main shaft and bearing are coaxially mounted.

[0017] The second main shaft is connected to the damping wheel on the other side. The second main shaft and the second bearing are coaxially installed. The two damping wheels are pressed onto the overhead rail of the stacker crane. The clamping force is adjusted by adjusting the screw and the compression spring to maintain sufficient friction.

[0018] Optionally, the servo motor is a permanent magnet synchronous servo motor with a rated torque of 45 N·m and a rated power of 3 kW.

[0019] Secondly, the present invention provides a control method for a stacker crane based on servo motor anti-sway control, comprising the following steps:

[0020] Step S1: System initialization and calibration phase;

[0021] Step S2: Dynamic anti-sway control stage of stacker crane operation;

[0022] Step S3: Braking and stabilizing phase, strong damping and sway control phase.

[0023] Optionally, the specific operation flow of step S1 is as follows:

[0024] Step S11: After the system is powered on, it completes a self-test: it checks the communication status of the tilt sensor, the fault status of the servo motor, and the validity of the walking and lifting encoder signals. If there are no faults, it proceeds to the calibration process.

[0025] Step S12, tilt sensor zero-point calibration: Control the stacker crane to stand still and unload for 10 seconds, collect the tilt angle value at this time as the zero-point reference, and eliminate the influence of installation error;

[0026] Step S13, Servo system inertia identification: Under no-load conditions, drive the servo motor to drive the damping wheel to rotate at low speed, automatically identify the load inertia, adjust the servo control gain, and ensure stable output of damping wheel torque.

[0027] Step S14: Import anti-sway control parameters: The PLC loads the preset anti-sway damping coefficient Kd, sway allowable threshold θmax, damping torque upper limit, walking speed and acceleration, and positioning stabilization time.

[0028] Optionally, the specific operation flow of step S2 is as follows:

[0029] Step S21: The PLC receives the inbound and outbound operation instructions, performs S-curve speed planning based on the target position, and reads the fork height value of the lifting encoder and the cargo weight value of the load sensor to match the anti-sway damping coefficient for the corresponding working condition.

[0030] Step S22: During the stacker crane's movement, the tilt sensor collects the swing angle θ and swing angular velocity ω of the upper beam weld in real time and transmits them to the PLC, and the motor encoder obtains the movement position and speed.

[0031] Step S23: When the stacker crane enters the acceleration / deceleration stage, the PLC outputs the basic damping torque corresponding to the acceleration / deceleration to the servo driver in advance to counteract the initial swaying inertia.

[0032] Step S24: Based on the real-time acquired sway angular velocity ω, the PLC calculates the dynamic compensation torque through an anti-sway damping algorithm, adds it to the basic damping torque, and sends it to the servo driver to achieve real-time sway suppression.

[0033] Optionally, the specific operation flow of step S3 is as follows:

[0034] Step S31: When the stacker crane travels to a distance of 1-2 times the braking distance from the target position, the strong damping control mode is triggered, and the servo motor switches to torque control mode.

[0035] Step S32: The servo motor receives the torque command and outputs the reverse damping torque, which counteracts the swaying inertia through the friction between the damping wheel and the overhead track.

[0036] Step S33: When the PLC detects that the swing angle is less than the preset swing allowable threshold θmax for 100ms, it determines that the swing suppression is completed and locks the output torque of the servo motor.

[0037] Step S34: Output a pick-up and drop-off permission command to the forklift control system to execute subsequent inbound and outbound operations.

[0038] Optionally, the anti-sway damping coefficient is calculated by combining the base damping coefficient, the current real-time load of the stacker crane, the rated maximum load of the stacker crane, the normalized sway angle fluctuation rate, and the relative height coefficient of the loading platform. The anti-sway damping coefficient is dynamically adjusted through two dimensions: load rate and sway severity. The relationship between the height of the loading platform and the equivalent sway inertia of the cantilever end of the column is also considered to make the anti-sway damping coefficient adaptive.

[0039] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0040] I. This invention uses active servo damping to counteract the swaying inertia during the acceleration, deceleration, start-up, and stop of the stacker crane in real time, eliminating the inertial swaying phenomenon of the upper beam and column from the root, avoiding fork alignment deviation caused by swaying, effectively improving the positioning accuracy of the stacker crane operation, ensuring the adaptability of picking and placing goods to the target storage location, and eliminating alignment failure problems caused by swaying.

[0041] Second, this invention can achieve stable stopping control without waiting for the sway to decay naturally, eliminating the wasteful waiting process of swaying in traditional solutions, greatly reducing the total time of a single operation, improving the overall operational efficiency of the stacker crane, and adapting to the operational needs of high-turnover warehousing scenarios.

[0042] Third, the active damping output of this invention can directly offset the alternating load generated by swaying, avoid the core load-bearing structures such as stacker crane columns and upper and lower crossbeams from bearing reciprocating stress impacts for a long time, effectively reduce the fatigue wear rate of structural components, extend the service life of the stacker crane as a whole, and reduce the manpower and cost investment in later operation and maintenance.

[0043] Fourth, the damping wheel clamping force of the anti-sway component of the present invention can be flexibly adjusted to adapt to stacker crane application scenarios with different loads, different operating speeds and different installation precisions. It does not require large-scale structural modifications for specific working conditions, has strong versatility, and can switch to passive damping mode in abnormal conditions to ensure basic operation. The machine operation will not be interrupted due to the failure of the anti-sway component, and the operation reliability is higher. Attached Figure Description

[0044] Figure 1 This is an isometric drawing of a stacker crane based on servo motor anti-sway control.

[0045] Figure 2 This is a top view schematic diagram of a stacker crane based on servo motor anti-sway control;

[0046] Figure 3 This is a schematic diagram of the fixed bracket, the first swing bracket, the second swing bracket, and the tilt sensor of the present invention;

[0047] Figure 4 This is a detailed schematic diagram of the servo motor anti-sway component of the present invention;

[0048] Figure 5 This is a cross-sectional view of the servo motor anti-sway component of the present invention;

[0049] Figure 6 This is a cross-sectional view of the servo motor anti-sway component of the present invention;

[0050] Figure 7 This document outlines the control method flow for a stacker crane based on servo motor anti-sway control. Figure 1 ;

[0051] Figure 8 This document outlines the control method flow for a stacker crane based on servo motor anti-sway control. Figure 2 .

[0052] In the diagram: 1. Front column; 2. Rear column; 3. Servo motor anti-sway assembly; 4. Front guide wheel; 5. Rear guide wheel; 6. Anti-collision block; 7. Upper beam welded component; 8. Rope pulley; 9. Tilt sensor; 31. Fixed bracket; 32. Swing bracket one; 33. Swing bracket two; 34. Swing shaft; 35. Adjusting screw; 36. Adjusting nut; 37. Compression spring; 38. Swing rod; 39. Swing rod shaft; 40. Servo motor; 41. Damping wheel; 42. Main shaft one; 43. Bearing one; 44. Main shaft two; 45. Bearing two. Detailed Implementation

[0053] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0054] Please see Figures 1 to 8 This embodiment provides a stacker crane based on servo motor anti-sway control, including:

[0055] Front column 1 and rear column 2, with upper beam welded parts 7 installed on the front column 1 and rear column 2, together forming the upper frame of the stacker crane;

[0056] Front guide wheel 4 and rear guide wheel 5 are respectively installed on the end plates at the front and rear ends of the upper beam weldment 7;

[0057] Two anti-collision blocks 6 are fixed to the outer end faces of the front guide wheel 4 and the rear guide wheel 5 respectively by bolts;

[0058] Two sets of rope pulleys 8 are fixed to the side of the upper beam weldment 7 through bearing seats. They cooperate with the wire rope to realize the lifting and lowering transmission of the forks.

[0059] Tilt sensor 9 is installed on the front column 1. Tilt sensor 9 is used to detect the tilt of the column when the stacker crane shakes, so as to transmit a signal to the PLC to indicate the suppression of the stacker crane shaking.

[0060] Servo motor anti-sway component 3 is installed on the upper beam weld 7. Servo motor anti-sway component 3 is used to calculate the reverse damping torque to counteract the swaying and apply resistance opposite to the swaying direction to deal with the swaying of the column before and after the stacker crane accelerates, decelerates and starts and stops.

[0061] In this embodiment: It should be noted that the overall operating logic of this solution is as follows:

[0062] When the servo motor 40 is powered on, the corresponding parameters are set so that the motor maintains torque at zero speed. When the upper beam welded part 7 attempts to rotate the motor shaft, the servo motor 40 senses this force and immediately outputs a reverse torque equal to the set value to resist it. When the external force exceeds the set torque and continues to act, the servo motor 40 will rotate slowly within the set speed without jamming. The servo motor 40 is installed on the upper beam welded part 7, and the damping wheel 41 coaxially connected with the servo motor 40 presses tightly against the top rail. The top rail refers to the walking guide rail at the top of the stacker crane aisle. When the stacker crane brakes, the servo motor 40 acts as an anti-sway damper, and the anti-sway effect is fed back through the tilt sensor 9. The servo motor 40 is controlled again to take anti-sway control, effectively suppressing the swaying of the upper beam welded part 7 when the stacker crane brakes.

[0063] Please refer to Figures 1-6 The servo motor anti-sway component 3 includes:

[0064] Fixed bracket 31 is installed on the side of the upper beam weldment 7. Fixed bracket 31 has two shaft holes, through which swing shaft 34 passes. Swing bracket 1 32 and swing bracket 2 33 are respectively sleeved on swing shaft 34.

[0065] An adjusting screw 35 is provided, with a rocker arm 38 threadedly connected to one end of the adjusting screw 35. A rocker arm shaft 39 is rotatably connected to the rocker arm 38, and the rocker arm shaft 39 is rotatably connected to the second swing bracket 33. The other end of the adjusting screw 35 passes through the first swing bracket 32. A compression spring 37 is sleeved on the outside of the adjusting screw 35. One end of the compression spring 37 abuts against the side of the first swing bracket 32, and the other end of the compression spring 37 is locked by an adjusting nut 36.

[0066] Servo motor 40, the flange of servo motor 40 is installed below swing bracket 32, servo motor 40 is connected to damping wheel 41 on one side through main shaft 42, and main shaft 42 is coaxially installed with bearing 43.

[0067] Main shaft 44 is connected to damping wheel 41 on the other side. Main shaft 44 and bearing 45 are coaxially mounted. The two damping wheels 41 are clamped onto the overhead rail of the stacker crane. The clamping force is adjusted by adjusting screw and compression spring to maintain sufficient friction.

[0068] Please refer to Figures 1-6 The servo motor 40 is a permanent magnet synchronous servo motor;

[0069] In this embodiment: the preferred motor is a permanent magnet synchronous servo motor. This type of motor has good back electromotive force linearity, high torque density, stable power generation, and the damping is the easiest to implement closed-loop control.

[0070] The rated torque of the servo motor 40 is 45 N·m;

[0071] In this embodiment: the rated torque of the damping motor is ≥1.2-1.5×the maximum anti-sway damping torque, because the damping torque is a continuous reverse output load and cannot be calculated by referring to the selection standard for short-term overload conditions.

[0072] Furthermore, regarding the speed range: the damping force = the reverse torque generated by the motor, it is necessary to ensure that the maximum disturbance speed is less than or equal to the rated speed of the motor. If it exceeds this range, the magnetism will weaken, the damping will suddenly decrease, and it will become uncontrollable.

[0073] Furthermore, regarding rotor inertia, if a strong damping and fast convergence damping effect is desired, a motor with a larger inertia should be selected; if a smooth and light damping effect is desired, a motor with a smaller inertia should be selected.

[0074] Furthermore, the larger the line back EMF constant, the higher the generated voltage at the same speed. Motors with larger line back EMF constants are preferred, as they are easier to achieve strong damping.

[0075] The servo motor 40 has a rated power of 3kW;

[0076] In this embodiment: the servo motor acts as damping, which essentially means that the motor generates electromagnetic torque in the opposite direction of motion, converting mechanical kinetic energy into electrical energy (feedback / consumption), thereby providing speed-related damping force;

[0077] When selecting servo damping, pay attention to the following: controllable reverse torque, power generation capability, stability, and adjustable damping. Therefore, the key considerations for servo motor selection are:

[0078] Maximum damping force / braking torque (must cover load disturbance);

[0079] Electric motor power generation capacity (damping is essentially power generation);

[0080] Damping algorithms supported by the driver;

[0081] The effectiveness of system inertia matching depends on the quality of damping.

[0082] Please see Figure 7 and Figure 8 This embodiment provides a control method for a stacker crane based on servo motor anti-sway control, including the following steps:

[0083] Step S1: System initialization and calibration phase;

[0084] Step S11: After the system is powered on, it completes a self-test: it checks the communication status of the tilt sensor 9, the fault status of the servo motor 40, and the validity of the walking and lifting encoder signals. If there are no faults, it proceeds to the calibration process.

[0085] Step S12, tilt sensor zero-point calibration: Control the stacker crane to stand still and unload for 10 seconds, collect the tilt angle value at this time as the zero-point reference, and eliminate the influence of installation error;

[0086] Step S13, Servo system inertia identification: Under no-load conditions, drive the servo motor 40 to drive the damping wheel 41 to rotate at low speed, automatically identify the load inertia, adjust the servo control gain, and ensure that the torque output of the damping wheel 41 is stable.

[0087] Step S14: Import anti-sway control parameters: The PLC loads the preset anti-sway damping coefficient Kd, sway allowable threshold θmax, damping torque upper limit, walking speed and acceleration, and positioning stabilization time.

[0088] PLC stands for Programmable Logic Controller;

[0089] Step S2: Dynamic anti-sway control stage of stacker crane operation;

[0090] The specific operation process of step S2 is as follows:

[0091] Step S21: The PLC receives the inbound and outbound operation instructions, performs S-curve speed planning based on the target position, and reads the fork height value of the lifting encoder and the cargo weight value of the load sensor to match the anti-sway damping coefficient for the corresponding working condition.

[0092] Step S22: During the stacker crane's movement, the tilt sensor 9 collects the swing angle θ and swing angular velocity ω of the upper crossbeam in real time and transmits them to the PLC, and the motor encoder obtains the walking position and speed.

[0093] Step S23: When the stacker crane enters the acceleration / deceleration stage, the PLC outputs the basic damping torque corresponding to the acceleration / deceleration to the servo driver in advance to counteract the initial swaying inertia.

[0094] Step S24: Based on the real-time acquired sway angular velocity ω, the PLC calculates the dynamic compensation torque through the anti-sway damping algorithm, adds it to the basic damping torque, and sends it to the servo driver to achieve real-time suppression of sway.

[0095] The load sensor can be installed at the bottom of the loading platform to collect cargo weight data in real time and transmit it to the PLC.

[0096] The further calculation formula for the anti-sway damping algorithm is as follows:

[0097] Tdamping = -Kd ×ω (i.e., the damping torque opposite to the direction of the swaying).

[0098] Step S3: Braking and stabilizing phase, strong damping and sway control phase;

[0099] Step S31: When the stacker crane travels to a distance of 1-2 times the braking distance from the target position, the strong damping control mode is triggered, and the servo motor switches to torque control mode.

[0100] Step S32: The servo motor receives the torque command and outputs the reverse damping torque, which cancels the swaying inertia through the friction between the damping wheel 41 and the ceiling track.

[0101] Step S33: When the PLC detects that the swing angle is less than the preset swing allowable threshold θmax for 100ms, it determines that the swing suppression is completed and locks the output torque of the servo motor.

[0102] Step S34: Output a pickup / dispatch permission command to the forklift control system to execute subsequent inbound / outbound operations.

[0103] In this embodiment: the stacker crane and control method based on servo motor anti-sway control can shorten the stabilization time when the stacker crane stops, effectively shorten the stabilization waiting time after the stacker crane stops, and improve the overall operation efficiency. It can be reduced from the initial 2-3 seconds to 0.3-0.8 seconds, and the operating efficiency can be improved by 20-30% (without waiting for stabilization).

[0104] It can also effectively solve the swaying problem of the upper beam welded parts 7 and the column when the stacker is braking, and improve the positioning accuracy of the stacker from ±5mm to ±2mm;

[0105] It can also promptly suppress the swaying state of the stacker, reduce the stress value of the column, and extend the fatigue life and mechanical life of the stacker (the stress of the column is reduced by 40-60%).

[0106] Please see Figures 1 to 8 The anti-sway damping coefficient kd is calculated by combining the basic damping coefficient, the current real-time load of the stacker crane, the rated maximum load of the stacker crane, the normalized sway angle fluctuation rate, and the relative height coefficient of the loading platform. The anti-sway damping coefficient is dynamically adjusted through two dimensions: load rate and sway severity. The relationship between the height of the loading platform and the equivalent sway inertia of the column cantilever end is also considered to make the anti-sway damping coefficient adaptive.

[0107] Please see Figure 7 and Figure 8 Furthermore, the formula for calculating the anti-sway damping coefficient kd is as follows:

[0108] ;

[0109] in:

[0110] kd refers to the anti-sway damping coefficient, which is a dynamically adaptive anti-sway damping coefficient. This parameter is a damping ratio coefficient that is dynamically adjusted according to the real-time operating conditions of the stacker crane. It directly determines the output strength of the damping torque of the anti-sway servo motor. This parameter serves as the core reference parameter for anti-sway control, enabling adaptive matching of damping output under different operating conditions. It avoids the problem of excessive output damping in light-load scenarios and insufficient output damping in heavy-load scenarios when the fixed damping coefficient is used.

[0111] kd0 refers to the basic damping coefficient, which is the fixed reference value of the anti-sway damping coefficient calibrated at the factory under no-load conditions. It can be obtained by multiple sway suppression tests under standard working conditions with no load and the loading platform at the lowest height before the equipment leaves the factory. It is pre-stored in the fixed parameter storage area of ​​the PLC and can be directly read and called when needed. The introduction of this parameter provides a calibration reference for the dynamic damping coefficient. Each stacker crane of the same model corresponds to a unique reference value, ensuring the consistency of the anti-sway control reference for the same model of equipment.

[0112] m refers to the real-time load mass, which is the real-time mass value of the goods currently carried by the stacker crane's loading platform. It can be directly collected by the weighing pressure sensor installed at the bottom of the loading platform. The analog signal output by the sensor is converted into the actual mass value by the PLC. This parameter is the core influencing parameter of the stacker crane's overall sway inertia, directly reflecting the magnitude of the sway inertia corresponding to the current load.

[0113] m max This refers to the rated maximum load, which is the rated maximum load capacity specified during the design phase of the stacker crane. It is an inherent design parameter of the equipment and can be pre-stored in the fixed parameter storage area of ​​the PLC. It can be directly read and called when needed. This parameter serves as the benchmark value for load rate calculation, normalizing the real-time load to a uniform dimensionless range and avoiding excessive adjustment of the damping coefficient due to differences in different load levels.

[0114] kds refers to the normalized sway angle fluctuation rate, which is the normalized sway angle fluctuation amplitude of the upper beam welded component 7 in the past 1 second. This parameter is first collected by the tilt sensor 9 installed on the upper beam welded component 7 in the past 0.2-0.5 seconds to calculate the maximum change of sway angle in 1 second Kdsa, and then divided by the maximum allowable change of sway angle preset by the stacker crane, that is, the sway allowable threshold θmax. The calculation formula is Kds=Kdsa÷θmax. The introduction of this parameter characterizes the severity of the current sway of the upper beam and directly reflects the current demand intensity for damping compensation.

[0115] kdh refers to the relative height coefficient of the loading platform, which is the ratio of the current height of the loading platform to the maximum lifting height of the stacker crane. It can be obtained by directly collecting the real-time absolute height hh of the loading platform through the encoder of the stacker crane's lifting shaft and then dividing it by the maximum lifting height hmax of the stacker crane. The calculation formula is Kdh = hh ÷ hmax. The introduction of this parameter characterizes the magnitude of the equivalent swaying inertia of the cantilever end caused by the height of the loading platform. The higher the height, the greater the equivalent swaying inertia.

[0116] Because existing anti-sway solutions generally ignore the impact of loading height on sway characteristics, and the higher the loading platform is, the greater the equivalent sway inertia at the cantilever end of the column, the worse the anti-sway effect is under the same damping coefficient. Especially in high-rise warehouses above 20 meters, the problem of high-rise anti-sway failure is common. After introducing this parameter, the damping coefficient will automatically increase with the loading height, and the anti-sway stability across the entire height range can be improved by more than 25%, and this can be achieved without adding any new hardware, which fits the actual application needs of high-rise warehouses.

[0117] It refers to the ratio of real-time travel speed to rated maximum travel speed, used to supplement damping correction under high-speed conditions, because the faster the stacker crane travels, the greater the impact during acceleration and deceleration, and the stronger the initial swaying inertia.

[0118] K1, k2, k3, and k4 refer to weighting coefficient one, weighting coefficient two, weighting coefficient three, and weighting coefficient four, respectively. They can be calibrated by bench testing before leaving the factory according to the height and rated load parameters of the stacker crane to adapt to different working conditions. In this embodiment, the preset values ​​of K1, k2, k3, and k4 are 0.6, 0.4, 0.3, and 0.2, respectively.

[0119] In this embodiment: the servo motor outputs a reverse damping torque to suppress the swaying of the upper beam during stacker braking. The effectiveness of the damping torque output depends on the matching degree between the damping coefficient and the current working condition. Traditional fixed damping coefficients can only adapt to the single working condition calibrated by the factory, and cannot cover the full scenario differences of load, cargo height and swaying state in the actual operation of the stacker crane. It is very easy for parameter adaptation deviation to occur. This formula incorporates the three core variables that directly affect the swaying characteristics during the operation of the stacker crane (real-time cargo weight, swaying intensity and cargo platform height) into the calculation logic of the damping coefficient. It realizes the dynamic adaptive adjustment of the damping coefficient with the real-time working condition, fundamentally solves the core pain point of the mismatch between the fixed damping coefficient and the actual working condition, and provides a benchmark parameter that is fully adapted to the current operating state for the entire anti-sway control system. It is the core support for the adaptive anti-sway capability of this invention.

[0120] The anti-sway damping coefficient kd is the core upstream input parameter of the entire anti-sway control system. It directly affects the subsequent damping torque calculation module, determining the baseline strength of the damping torque output. This parameter integrates the originally isolated load information, height information, and sway state information into a unified damping adaptation benchmark. This allows for matching all operating conditions without manual parameter switching, avoiding energy redundancy and structural reverse impact caused by excessive damping in light-load scenarios under fixed parameters, and sway suppression failure caused by insufficient damping in heavy-load, high-lift scenarios. It is the prerequisite for achieving accurate output in the entire anti-sway control closed loop.

[0121] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A control method for a stacker crane based on servo motor anti-sway control, characterized in that, Stacker cranes include: Front column (1) and rear column (2), with upper beam welded parts (7) provided on the front column (1) and the rear column (2), together forming the upper frame of the stacker crane; The front guide wheel (4) and the rear guide wheel (5) are respectively installed on the end plates at the front and rear ends of the upper beam weldment (7); Two anti-collision blocks (6) are fixed to the outer end faces of the front guide wheel (4) and the rear guide wheel (5) respectively by bolts; Two sets of rope pulleys (8) are fixed to the side of the upper beam weldment (7) by bearing seats. They cooperate with the wire rope to realize the lifting and lowering transmission of the forks. Inclination sensor (9), the inclination sensor (9) is installed on the front column (1), the inclination sensor (9) is used to detect the tilt of the column when the stacker crane shakes, so as to transmit a signal to the PLC to indicate the suppression of the stacker crane shaking; Servo motor anti-sway component (3), the servo motor anti-sway component (3) is installed on the upper beam weld (7), the servo motor anti-sway component (3) is used to calculate the reverse damping torque to counteract the swaying, and apply resistance opposite to the swaying direction to deal with the swaying of the column before and after the stacker crane accelerates, decelerates and starts and stops; The control method for stacker cranes includes the following steps: Step S1: System initialization and calibration phase; Step S2: Dynamic anti-sway control stage of stacker crane operation; Step S3: Braking and stabilizing phase, strong damping and sway control phase; The specific operation process of step S1 is as follows: Step S11: After the system is powered on, complete the self-test: check the communication status of the tilt sensor (9), the fault status of the servo motor (40), and the validity of the walking and lifting encoder signals. If there is no fault, proceed to the calibration process. Step S12, tilt sensor zero-point calibration: Control the stacker crane to stand still and unload for 10 seconds, collect the tilt angle value at this time as the zero-point reference, and eliminate the influence of installation error; Step S13, Servo system inertia identification: Under no-load conditions, drive the servo motor (40) to drive the damping wheel (41) to rotate at low speed, automatically identify the load inertia, adjust the servo control gain, and ensure that the torque output of the damping wheel (41) is stable. Step S14: Import anti-sway control parameters: The PLC loads the preset anti-sway damping coefficient Kd, sway allowable threshold θmax, damping torque upper limit, walking speed and acceleration, and positioning stabilization time.

2. The control method for a stacker crane based on servo motor anti-sway control according to claim 1, characterized in that: The servo motor anti-sway component (3) includes: Fixed bracket (31) is installed on the side of the upper beam weldment (7). The fixed bracket (31) has two shaft holes. The swing shaft (34) passes through the shaft holes. Swing bracket one (32) and swing bracket two (33) are respectively sleeved on the swing shaft (34). An adjusting screw (35) is provided. One end of the adjusting screw (35) is threadedly connected to a rocker arm (38). A rocker arm shaft (39) is rotatably connected to the rocker arm (38). The rocker arm shaft (39) is rotatably connected to the second swing bracket (33). The other end of the adjusting screw (35) passes through the first swing bracket (32). A compression spring (37) is sleeved on the outside of the adjusting screw (35). One end of the compression spring (37) abuts against the side of the first swing bracket (32). The other end of the compression spring (37) is locked by an adjusting nut (36). Servo motor (40), the flange of the servo motor (40) is installed below the swing bracket (32), the servo motor (40) is connected to the damping wheel (41) on one side through the main shaft (42), the main shaft (42) and the bearing (43) are coaxially installed; The second main shaft (44) is connected to the damping wheel (41) on the other side. The second main shaft (44) and the second bearing (45) are coaxially installed. The two damping wheels (41) are pressed on the overhead rail of the stacker. The clamping force is adjusted by adjusting the screw and the compression spring to maintain sufficient friction.

3. The control method for a stacker crane based on servo motor anti-sway control according to claim 2, characterized in that: The servo motor (40) is a permanent magnet synchronous servo motor with a rated torque of 45 N·m and a rated power of 3 kW.

4. The control method for a stacker crane based on servo motor anti-sway control according to claim 1, characterized in that: The specific operation flow of step S2 is as follows: Step S21: The PLC receives the inbound and outbound operation instructions, performs S-curve speed planning based on the target position, and reads the fork height value of the lifting encoder and the cargo weight value of the load sensor to match the anti-sway damping coefficient for the corresponding working condition. Step S22: During the movement of the stacker crane, the tilt sensor (9) collects the swing angle θ and swing angular velocity ω of the upper beam weldment (7) in real time and transmits them to the PLC, and the motor encoder obtains the walking position and speed. Step S23: When the stacker crane enters the acceleration / deceleration stage, the PLC outputs the basic damping torque corresponding to the acceleration / deceleration to the servo driver in advance to counteract the initial swaying inertia. Step S24: Based on the real-time acquired sway angular velocity ω, the PLC calculates the dynamic compensation torque through an anti-sway damping algorithm, adds it to the basic damping torque, and sends it to the servo driver to achieve real-time sway suppression.

5. The control method for a stacker crane based on servo motor anti-sway control according to claim 4, characterized in that: The specific operation process of step S3 is as follows: Step S31: When the stacker crane travels to a distance of 1-2 times the braking distance from the target position, the strong damping control mode is triggered, and the servo motor switches to torque control mode. Step S32: The servo motor receives the torque command and outputs the reverse damping torque, which cancels the swaying inertia through the friction between the damping wheel (41) and the ceiling track. Step S33: When the PLC detects that the swing angle is less than the preset swing allowable threshold θmax for 100ms, it determines that the swing suppression is completed and locks the output torque of the servo motor. Step S34: Output a pickup / dispatch permission command to the forklift control system to execute subsequent inbound / outbound operations.

6. The control method for a stacker crane based on servo motor anti-sway control according to claim 4, characterized in that: The anti-sway damping coefficient is calculated by combining the base damping coefficient, the current real-time load of the stacker crane, the rated maximum load of the stacker crane, the normalized sway angle fluctuation rate, and the relative height coefficient of the loading platform. The anti-sway damping coefficient is dynamically adjusted through two dimensions: load rate and sway severity. The relationship between the height of the loading platform and the equivalent sway inertia of the cantilever end of the column is also considered to make the anti-sway damping coefficient adaptive.

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