Electromagnetic anti-swing mechanism of stacking machine and method of electromagnetic anti-swing mechanism

Abstract

The invention provides an electromagnetic anti-swing mechanism of a stacking machine and a method thereof, belongs to the field of logistics sorting, and aims to realize anti-swing control through an eddy current damping effect on the basis of an electromagnetic induction principle of a Lenz's law. Therefore, the purposes of simplifying the structural design of a related braking mechanism, improving the anti-swing performance of the stacking machine, being suitable for different machine body heights, solving the contradiction between high speed and stability and remarkably improving the overall operation efficiency and safety of a three-dimensional warehouse are achieved. The electromagnetic anti-swing mechanism comprises a non-contact electromagnetic damping module which is installed on the opposite side of the sky rail, on the upper cross beam of the stacking machine and used for generating an electromagnetic field, an eddy current conductor plate assembly installed on the goods shelf, and a dynamic sensing feedback system installed on the upper cross beam of the stacking machine and used for achieving dynamic feedback closed-loop control of an electromagnetic system.

Description

Technical Field

[0001] This application belongs to the field of logistics sorting and automation equipment, and particularly relates to an electromagnetic anti-sway mechanism applicable to material handling equipment such as stackers and cranes, and a control method applying this mechanism. Background Art

[0002] With the rapid development of domestic and foreign logistics transportation automation technology, three-dimensional warehousing has been widely popularized. How to further improve the operation efficiency of stackers, which are the core handling equipment, has become the main technical issue. Currently, stackers generally adopt a high-speed operation design. However, in actual high-speed operation, the inertia generated by sudden stops directly leads to significant swinging of the equipment. Stackers have a relatively high and narrow overall structure. Existing braking devices are usually installed at the bottom of the equipment. Although the bottom can be quickly braked during sudden stops, the upper structure of the equipment continues to swing significantly due to inertia, thus causing various problems. For example, the positioning accuracy decreases. The swinging makes it difficult for the forklift to accurately align with the target storage location, and it is necessary to wait for the equipment to come to a complete stop before operation, seriously affecting the operation efficiency; the potential safety hazards are prominent. The swinging amplitude increases with the increase in the height of the stacker, easily leading to the risk of goods tilting or even collapsing; the efficiency loss is significant. For every 5-meter increase in the equipment height, the stable waiting time after a single braking is extended by about 30%-50%, resulting in the accumulation of a large amount of ineffective working hours.

[0003] In response, the following prior publicly disclosed technologies have attempted to make relevant improvements. For example, a patent application with the publication number CN117699294A and the title of a stacker top anti-sway control device and method adds an anti-sway motor above the traditional stacker structure at the control system level. Through the electrical control system, the bottom traveling motor and the upper anti-sway motor are synchronized in height. However, although this solution can achieve the anti-sway function, it overly increases the equipment cost. It not only adds an anti-sway motor, but also the control system needs to be supplemented, such as an anti-sway frequency converter, an upper laser rangefinder, etc. Moreover, the overall solution is based on the control level, and its reliability remains to be questioned;

[0004] Another example is a patent application with the publication number CN220165740U and the title of a stacker anti-sway device, which controls the anti-sway of the stacker from the mechanical system. It adds a sky rail gear rack and a ground rail gear rack, and an intermediate shaft mechanism and a fixed seat are added in the middle. The stacker anti-sway is achieved through synchronous braking of the sky rail and ground rail gear rack transmissions. However, it also has the following main defects: First, the overall mechanism is a traditional mechanical limiter, and the response time > 250ms; second, the gear rack transmission adds an extra level of transmission, reducing the efficiency of the overall equipment; third, the mechanical gear rack meshing will affect the service life of the whole machine equipment, causing corresponding wear and increasing the subsequent maintenance time of the equipment.

[0005] The above-mentioned existing technologies generally have problems such as complex structures, response lags, or poor adaptability. It is difficult to achieve rapid stability under high-speed working conditions, and the mechanical clamping braking mechanism has obvious wear after long-term use, posing great difficulties for subsequent personnel maintenance. In view of this, this patent application is specifically proposed. Summary of the Invention

[0006] An electromagnetic anti-sway mechanism and control method for a stacker in this application aims to solve the problems existing in the above-mentioned existing technologies. Based on the electromagnetic induction principle of Lenz's law, anti-sway control is achieved through the eddy current damping effect, so as to simplify the structural design of relevant braking mechanisms, improve the anti-sway performance of the stacker, be applicable to different body heights, solve the contradiction between high speed and stability, and significantly improve the overall operation efficiency and safety of the three-dimensional warehouse.

[0007] To achieve the above design objectives, the electromagnetic anti-sway mechanism of the stacker includes a non-contact electromagnetic damping module installed on the opposite side of the overhead rail and on the upper crossbeam of the stacker for generating an electromagnetic field, an eddy current conductor plate assembly installed on the shelf, and a dynamic sensing feedback system installed on the upper crossbeam of the stacker for realizing dynamic feedback closed-loop control of the electromagnetic system; the non-contact electromagnetic damping module includes a bracket, and two groups of electromagnetic generating devices connected to the dynamic sensing feedback system are symmetrically arranged side by side on the bracket. The dynamic sensing feedback system adjusts the current value in the electromagnetic coil of the electromagnetic generating device to control the generation of different magnetic field intensities, and further controls the magnitude of the damping force generated by the eddy current effect; during the operation of the stacker, the electromagnetic generating device moves along the linear axis of the eddy current conductor plate assembly, and the eddy current conductor plate assembly maintains the same distance from the two groups of electromagnetic generating devices.

[0008] Furthermore, the eddy current conductor plate assembly includes a three-layer structure connected vertically and superimposed. The upper surface layer is a high-conductivity oxygen-free copper strip with a thickness between 5-8 mm and an electrical conductivity ≥ 5.8×10 7 S / m; the middle layer is a fiberglass epoxy resin heat insulation layer; the base layer is an aluminum substrate with a tensile strength ≥ 310 MPa.

[0009] Furthermore, the dynamic sensing feedback system includes a MEMS sensor and a laser displacement meter that are electrically connected to each other. The MEMS sensor real-time collects the angular velocities ω x of the stacker's swing in the X-axis and Y-axis in the three-dimensional coordinate system, y the laser displacement meter monitors the amplitude A(t) generated by the upper crossbeam of the stacker, and through a speed-magnetic field coupling control method, dynamically adjusts the excitation current I coil in the electromagnetic coil of the electromagnetic generating device, so that the magnetic field intensity B generated by it changes correspondingly with the running speed v of the stacker, generating a damping braking force.

[0010] Based on the electromagnetic anti-sway mechanism of the above-mentioned stacker, the present application also proposes the following electromagnetic anti-sway method for the stacker:

[0011] Implement anti-sway control based on the eddy current damping effect, and adjust the magnitude of the damping force in real time by adjusting the current in the electromagnetic coil to achieve braking and attitude control during the operation of the stacker; obtain the running speed v of the stacker in real time running and the swinging speed v swing , based on the running speed v of the stacker running set the baseline magnetic field intensity as B0, and superimpose the swinging speed v swing to feedback and adjust the current, and dynamically update the magnetic field intensity as:

[0012]

[0013] wherein, K is an empirical coefficient, and its value ranges between 0.5 and 1.2; v swing is the swinging speed of the stacker; B0 is the baseline magnetic field intensity; v running-max is the maximum running speed of the stacker.

[0014] Furthermore, the damping force generated by the electromagnetic generating device conforms to the following expression

[0015]

[0016] wherein, σ is the conductivity of the eddy current conductor plate assembly, v is the speed at which the eddy current conductor plate assembly vertically cuts the magnetic field formed by the electromagnetic generating device, B is the magnetic field intensity, A is the cross-sectional area of the eddy current conductor plate assembly, d is the thickness of the eddy current conductor plate assembly, and L is the length of the eddy current conductor plate assembly.

[0017] In summary, the electromagnetic anti-sway mechanism and control method for the stacker proposed in the present application have the following advantages:

[0018] 1. The present application realizes actively adjustable anti-sway control through the eddy current damping effect. The conductor is placed in the magnetic field and moves along with the stacker. Inductive eddy currents are generated inside it, which interact with the magnetic field to generate a damping force opposite to the direction of motion, thereby suppressing the overall swing of the stacker and effectively achieving the attitude stability control performance during equipment braking and movement.

[0019] 2. The dynamic performance of the stacker is improved, and it has the ability of microsecond-level active suppression. The present application forms a non-linear impedance force field based on the eddy current damping effect of Lenz's law, and the response time is no more than 8 ms, while the mechanical braking time of the prior art is greater than 250 ms; at the same time, the present application can generate a resistance torque at the initial stage of the cargo swing, and the peak torque can reach 320 N·m.

[0020] 3. This application achieves zero mechanical wear. By using non-contact electromagnetic action to eliminate the losses between the brake wheel and the overhead rail, the equipment life is increased by 300%, and it has a maintenance-free performance of over 50,000 hours.

[0021] 4. The energy consumption of the stacker is optimized. The magnetic circuit multiplexing technology makes the standby energy consumption of the system no greater than 15W, while the energy consumption of the existing variable frequency braking schemes is greater than 800W. At the same time, this application can be combined with the energy feedback design to reduce the comprehensive energy consumption by 92%.

[0022] 5. This application features a simple structure and strong compatibility. By adopting a modular integration scheme, only an electromagnetic generating device and a composite conductor plate on the side of the overhead rail need to be installed on the existing upper crossbeam, and the transformation cost is reduced by about 70%.

[0023] 6. This application has high precision and high safety performance. The following swing suppression index levels are relatively high: at a rated speed of 2m / s (120m / min), the residual swing amplitude ≤ ±1.2mm (the international standard is ≤ ±5mm), the positioning and calibration waiting time is zero, while the existing technology requires a stabilization time of 3 - 8s. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present application will be further described in conjunction with the following drawings.

[0025] Figure 1 is an installation schematic diagram of the electromagnetic anti-sway mechanism of the stacker described in this application;

[0026] Figure 2 is a structural schematic diagram of the non-contact electromagnetic damping module;

[0027] Figure 3 is a schematic diagram of the stacker anti-sway;

[0028] Figure 4 and Figure 5 respectively are schematic diagrams of the damping force generation in two motion directions shown after rotating 90° in the A direction as in Figure 3 . In the figure, B represents the direction of the magnetic induction line, and v represents the running direction of the stacker. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] Example 1, as shown in Figure 1 and Figure 2 . This application proposes an electromagnetic anti-sway mechanism for a stacker based on the electromagnetic induction principle of Lenz's law, and realizes anti-sway control through the eddy current damping effect. Specifically, by adjusting the current in the electromagnetic coil, the magnitude of the damping force is adjusted in real time, so as to achieve effective braking and high-safety attitude stability control when the stacker runs at high speed.

[0030] The electromagnetic anti-sway mechanism of the stacker includes a non-contact electromagnetic damping module 1.1 for generating an electromagnetic field, which is installed on the upper crossbeam 1.5 of the stacker on the opposite side of the overhead rail 1.4, an eddy current conductor plate assembly 1.2 installed on the shelf (such as installed on the hanging beam of the shelf, not shown in the figure), and a dynamic sensing feedback system 1.3 installed on the upper crossbeam 1.5 of the stacker for realizing the dynamic feedback closed-loop control of the electromagnetic system;

[0031] The non-contact electromagnetic damping module 1.1 includes a bracket 1.1-1, and two groups of electromagnetic generating devices 1.1-2 connected to the dynamic sensing feedback system 1.3 are symmetrically arranged side by side on the bracket 1.1-1. The dynamic sensing feedback system 1.3 adjusts the current value in the electromagnetic coil of the electromagnetic generating device 1.1-2 to control the generation of different magnetic field intensities, and further controls the magnitude of the damping force generated by the eddy current effect, so as to meet the braking requirements of stackers at different heights and operating speeds;

[0032] During the operation of the stacker, the electromagnetic generating device 1.1-2 moves linearly along the axial direction of the eddy current conductor plate assembly 1.2, and the eddy current conductor plate assembly 1.2 maintains the same distance from the two groups of electromagnetic generating devices 1.1-2.

[0033] The eddy current conductor plate assembly 1.2 includes a three-layer structure connected vertically in a stacked manner. The upper surface layer is a high-conductivity oxygen-free copper strip with a thickness between 5-8 mm and an electrical conductivity ≥ 5.8×10 7 S / m; the middle layer is a fiberglass epoxy resin heat insulation layer with a heat resistance grade of H, such as a heat resistance aging of 180°C / 200 h; the base layer is a 6061-T6 aluminum substrate with a tensile strength ≥ 310 MPa, so as to meet the requirements of high conductivity, high strength and high temperature resistance at the same time.

[0034] The dynamic sensing feedback system 1.3 includes a MEMS sensor and a laser displacement meter that are electrically connected to each other. The MEMS sensor can collect the swing angular velocity ω of the stacker in the three-dimensional coordinate system in real time x , ω y and other data. The laser displacement meter can monitor the amplitude A(t) generated by the upper crossbeam of the stacker, as Figure 3 shown; the dynamic sensing feedback system 1.3 dynamically adjusts the excitation current I in the electromagnetic coil of the electromagnetic generating device 1.1-2 through a speed-magnetic field coupling control method coil , so that the generated magnetic field intensity B changes correspondingly with the operating speed v of the stacker, generating an efficient damping braking force.

[0035] As Figures 3 to 5 shown in the anti-sway control principle of the stacker, referring to the relevant directions of the generated magnetic field and damping force, the operating principle of the electromagnetic anti-sway mechanism of the stacker is as follows:

[0036] In a closed loop, the direction of the induced current is always perpendicular to the direction of the magnetic field it generates, thereby hindering the change in the original magnetic flux as described by the following expression: E = -dΦB / dt

[0037] Where ΦB is the magnetic flux, ε is the induced electromotive force, and the "-" (negative sign) indicates that the direction hinders the change. The magnetic field generated by the induced current interacts with the original magnetic field to form a reverse damping force, which can convert mechanical energy into heat energy for consumption, thereby achieving the active suppression of the swing of the stacker described in this application.

[0038] According to different scenarios of the stacker operation, the damping force required for active braking can be derived through the following expressions and parameters, that is, F 阻尼 :

[0039] Magnetic field cutting: The eddy current conductor plate assembly 1.2 (with conductivity set as σ) cuts the magnetic field with intensity B formed by the electromagnetic generation device 1.1-2 at a speed v perpendicularly;

[0040] Eddy current generation: Closed eddy currents are generated inside the eddy current conductor plate assembly 1.2 Where A is the cross-sectional area of the conductive plate; d is the thickness of the conductive plate;

[0041] Thus, the damping force F can be calculated 阻尼 = B·I 涡 ·L, where L is the effective action length of the conductive plate;

[0042] Combining the above formulas, it can be obtained that

[0043] As can be seen from the above content, when introducing vector direction analysis, the moving speed of the electromagnetic generation device 1.1-2 is to the left (←), the magnetic field is upward (↑); the equivalent moving direction of the eddy current vector is opposite to the running direction of the electromagnetic generation device 1.1-2, that is, to the right (→); that is, the direction of the Lorentz force is the opposite direction of the running direction of the electromagnetic generation device 1.1-2 Therefore, it can be known that the direction of the damping force is always opposite and perpendicular to the direction of the conductor movement (here is the lateral swing direction), thereby being able to play a role in actively suppressing the swing of the stacker.

[0044] Furthermore, it can be known that the above formula shows that the damping force is proportional to the square of the magnetic field strength, the speed, and the material conductivity.

[0045] Based on the above conclusions, for the electromagnetic anti-sway mechanism of the stacker described in this application, on the premise of the conductivity σ of the eddy current conductor plate assembly 1.2, the running speed v of the stacker is monitored in real time, and the magnetic field strength B generated by the electromagnetic generation device 1.1-2 is dynamically regulated. Through speed-magnetic field coupling control, the excitation current I is dynamically adjusted, and the magnetic field strength B is changed with the speed v according to the following expression:

[0046]

[0047] where k is an empirical coefficient to prevent excessive damping force, and the value of K ranges from 0.5 to 1.2; v swing is the swaying speed of the stacker; B0 is the baseline magnetic field strength; v running is the running speed of the stacker, and v running-max is the maximum running speed of the stacker. Since the stacker has acceleration and uniform running stages, it is distinguished in this way;

[0048] Furthermore, by calculating the swaying amplitude when the stacker stops, it is converted into the requirement for F 阻尼 ;

[0049] Generally, in a stacker, the load platform (including the goods) accounts for 50%-70% of the total mass of the stacker. Its inertia moment is significantly higher than that of other components (such as lightweight columns or frames) during emergency stops. Moreover, the load platform is connected to the column through a suspension system, mainly showing lateral translational sway (i.e., the single-degree-of-freedom vibration phenomenon around the suspension point), which is easier to model and control compared to the multi-degree-of-freedom vibration of the entire stacker. The subsequent calculations mainly focus on the load platform, and the relevant calculations are as follows:

[0050] The load platform generates a lateral offset due to inertia during braking, and the equivalent initial displacement x0 is calculated by the following formula:

[0051]

[0052] where H is the height of the center of gravity of the load platform; k c is the stiffness of the suspension system, with the unit of mg / L;

[0053] The following example calculation is provided (to introduce the relevant parameters and calculation methods preliminarily, but it does not mean that only the following working conditions are supported):

[0054] For example, for a stacker in a certain factory area, the weight of the goods it carries is 600 kg, the weight of the load platform is 1400 kg, the height of the stacker column is 12 m, the running speed is 4 m / s, that is, 240 m / min, and the braking deceleration is 3 m / s2. Calculate the swaying displacement generated by the above stacker during braking. Through the above working conditions, the braking time can be calculated as

[0055]

[0056] After substituting the above parameters into the above formula, t is obtained b = 1.33 s;

[0057] Then Substitute into the calculation of the swing displacement:

[0058]

[0059] Considering the structural rigidity of the column and the stacker, the equivalent displacement substituted into the upper crossbeam is as follows:

[0060]

[0061] That is, the swing displacement converted to the upper crossbeam is 34 mm. This data is only used to judge the swing of the stacker. Based on the column height, if the overall height continues to increase, the swing displacement of the upper crossbeam still increases linearly.

[0062] The following calculations are still mainly based on the load platform. The swing of the load platform satisfies the damped vibration equation:

[0063]

[0064] Among them, m = 2000 kg; k c = 1635 N / m; c = required damping coefficient;

[0065] To prevent overshoot residual swing (target < 1.2 mm), the damping ratio needs to be set to ζ = 0.7 (i.e., critical damping):

[0066] Then

[0067] The maximum swing speed and the peak damping force. During the braking process, the maximum lateral speed of the load platform appears at the initial movement moment:

[0068]

[0069] In the actual working condition, due to the emergency braking impact and it should be converted to the electromagnetic braking height, the measured peak speed v to be used swing = 0.8 m / s;

[0070] Then the peak damping force is F 阻尼 = c × v swing = 5016 × 0.8 ≈ 4013 N; A safety margin should be added in actual use, and 4500 N (±10%) is actually selected.

[0071] Then the electromagnetic parameters adopted in this application should be matched according to the above peak damping force, and the conductivity σ of the eddy current conductor plate assembly 1.2 is set to 5.8 × 10 7S / m, the effective length L = 2 m, the thickness d = 0.006 m, and the comprehensive cross-sectional area A = 0.3×0.006 = 0.0018 m 2 ;

[0072] With the above parameters, substituting into the eddy current damping formula:

[0073]

[0074] Based on the above magnetic flux, the exciting current can be deduced. Assuming the number of turns of the coil N = 1200, the air gap g = 10 mm, and the magnetic permeability μ0 = 4π×10 -7 H / m, the exciting current is deduced from the magnetic field strength formula as follows:

[0075]

[0076] An exciting current of 15 A (margin coefficient 1.08) can be selected, and then the magnetic field-velocity coupling formula is modified as:

[0077]

[0078] where (B0 = 0.21 T, v running-max = 4 m / s) the dynamic adjustment response time is controlled to be ≤8 ms;

[0079] Correspondingly, the energy power consumption is verified as follows: the coil resistance R = 0.5 Ω, the rated current I = 15 A,

[0080] The unilateral power consumption P = I 2 R = 112.5 W, and the total bilateral power consumption is 225 W.

[0081] In summary, the embodiments given in the accompanying drawings are only preferred solutions. For those skilled in the art, they can get inspiration from this and directly deduce other alternative structures that conform to the design concept of the present invention, which should also fall within the scope of the solutions described in the present invention.

Claims

1. An electromagnetic anti-sway mechanism for a stacker, characterized in that: It includes a non-contact electromagnetic damping module installed on the opposite side of the overhead rail and on the upper crossbeam of the stacker for generating an electromagnetic field, an eddy current conductor plate assembly installed on the shelf, and a dynamic sensing feedback system installed on the upper crossbeam of the stacker for realizing the dynamic feedback closed-loop control of the electromagnetic system; The non-contact electromagnetic damping module includes a bracket, and two groups of electromagnetic generating devices connected to the dynamic sensing feedback system are symmetrically arranged side by side on the bracket. The dynamic sensing feedback system adjusts the current value in the electromagnetic coil of the electromagnetic generating device to control different magnetic field intensities, thereby controlling the magnitude of the damping force generated by the eddy current effect; During the operation of the stacker, the electromagnetic generating device moves along the linear axis of the eddy current conductor plate assembly, and the eddy current conductor plate assembly maintains the same distance from the two groups of electromagnetic generating devices.

2. The electromagnetic anti-sway mechanism of the stacker according to claim 1, characterized in that: The described eddy current conductor plate assembly includes a three-layer structure connected in a vertical stack. The upper surface layer is a high-conductivity oxygen-free copper strip with a thickness between 5 - 8 mm and a conductivity ≥ 5.8×10 7 S / m; The middle layer is a fiberglass epoxy insulation layer; the base layer is an aluminum substrate with a tensile strength ≥ 310 MPa.

3. The electromagnetic anti-sway mechanism of the stacker according to claim 1, characterized in that: The described dynamic sensing feedback system includes a MEMS sensor and a laser displacement meter that are electrically connected to each other. The MEMS sensor real-time collects the angular velocities ω of the X-axis and Y-axis of the stacker crane's swing in a three-dimensional coordinate system. x , ω y , and the laser displacement meter monitors the amplitude A(t) generated by the upper crossbeam of the stacker crane. Through the velocity-magnetic field coupling control method, the excitation current I in the electromagnetic coil of the electromagnetic generating device is dynamically adjusted. coil , so that the magnetic field strength B generated by it changes correspondingly with the running speed v of the stacker crane, generating a damping braking force.

4. An electromagnetic anti-sway method for an electromagnetic anti-sway mechanism of a stacker according to any one of claims 1 to 3, characterized in that: Anti-sway control is achieved based on the eddy current damping effect. The magnitude of the damping force is adjusted in real time by adjusting the current in the electromagnetic coil, and braking and attitude control are achieved during the operation of the stacker; Obtain the running speed v of the stacker in real time running and the swing speed v swing , based on the running speed v of the stacker running Set the baseline magnetic field intensity to B0, and superimpose the swing speed v swing Feedback and adjust the current, and dynamically update the magnetic field intensity to Among them, K is an empirical coefficient, and its value ranges from 0.5 to 1.2; v swing is the swing speed of the stacker; B0 is the magnetic field baseline intensity; v running-max is the maximum running speed of the stacker.

5. The electromagnetic anti-sway method of the stacker according to claim 4, characterized in that: The damping force generated by the electromagnetic generating device conforms to the following expression, where σ is the conductivity of the eddy current conductor plate assembly, v is the speed at which the eddy current conductor plate assembly vertically cuts the magnetic field formed by the electromagnetic generating device, B is the magnetic field intensity, A is the cross-sectional area of the eddy current conductor plate assembly, d is the thickness of the eddy current conductor plate assembly, and L is the length of the eddy current conductor plate assembly.

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