A motion stability evaluation method for high-speed pallet-type four-way shuttle

Abstract

This invention relates to a comprehensive assessment method for the motion stability of a high-speed four-way shuttle vehicle, taking into account cargo offset. This method evaluates the stability of a pallet-carrying four-way shuttle vehicle at high speeds based on the rollover coefficient and proposes a corresponding calculation expression. This method comprehensively considers factors such as the friction between the pallet and the vehicle frame, the center of gravity of the stacked palletized cargo, and the motion and structural parameters of the automated four-way shuttle vehicle (ASRV), providing an assessment scheme for warehouse cargo handling safety.

Description

Technical Field

[0001] The invention relates to a comprehensive evaluation method for the motion stability of a high-speed four-way shuttle vehicle taking cargo bias into consideration, and belongs to the field of logistics and warehousing. Background Art

[0002] In recent years, driven by land scarcity and economic pressures, the Four-Way Shuttle Compact Storage and Retrieval System (FS-CS / RS) has been widely adopted by diverse enterprises, including pharmaceuticals, food and tobacco, cold chain logistics, e-commerce, and smart manufacturing. As one of these new types of compact storage systems, the racking layers are equipped with crisscrossing tracks. Four-way shuttle vehicles (ASRVs) can flexibly and freely coordinate with elevators to achieve storage and picking at any location within a three-dimensional space. While ASRVs enable heavy loads and high-speed handling within compact storage systems, these advantages also present safety risks. During handling operations, fully loaded ASRVs can be subject to various external factors, causing them to deviate from their normal trajectory and become unstable. Unlike reciprocating shuttles, which lack a positioning device to constrain palletized cargo, excessive misalignment of the center of gravity can cause high-speed ASRVs to overturn, leading to traffic congestion during inbound and outbound operations and even system safety incidents. Therefore, a motion stability evaluation method for high-speed pallet-type four-way shuttles considering cargo offset is proposed, which has positive practical significance for the safety design of four-way shuttle dense storage systems. Summary of the Invention

[0003] The purpose of this invention is to propose a motion stability assessment method for high-speed pallet-type four-way shuttle vehicles considering cargo offset, so as to assist in the safety design of four-way shuttle dense storage systems.

[0004] In order to achieve the above-mentioned purpose, the technical solution of the present invention is to provide a method for evaluating the motion stability of a high-speed pallet-type four-way shuttle vehicle. The high-speed pallet-type four-way shuttle vehicle runs on a transverse mother track and a longitudinal sub-track. The vehicle body of the high-speed pallet-type four-way shuttle vehicle is provided with front transverse wheels and rear transverse wheels that cooperate with the transverse mother track and front longitudinal wheels and rear longitudinal wheels that cooperate with the longitudinal sub-track. In addition, the vehicle body is provided with sensors 1, 2, 3 and 4 for measuring the load of pallet cargo. Sensors 1, 2, 3 and 4 are arranged at four angles, and in the left and right directions, sensor 1 and sensor 2 are on the same side, and sensor 3 and sensor 4 are on the same side. The method for evaluating the motion stability comprises the following steps:

[0005] 1) During the startup and acceleration phase of a high-speed pallet four-way shuttle, the anti-overturning coefficient C is calculated using the following formula: T :

[0006]

[0007] Where G h is the weight of the pallet cargo, G v is the weight of the high-speed pallet four-way shuttle vehicle, l1 and l2 are the distances between the center of mass O1 of the vehicle body and the center of mass O2 of the pallet cargo and the rear transverse wheel or rear longitudinal wheel of the vehicle body, respectively. v It is the distance between the front and rear transverse wheels or the front and rear longitudinal wheels of the vehicle body. a is the friction between the pallet cargo and the top surface of the upper frame, h v is the vehicle body thickness, h1 is the height of the center of gravity of the high-speed pallet four-way shuttle vehicle, h2 is the height of the center of gravity of the pallet cargo, F1 and F2 are the contact forces between the front transverse wheels of the vehicle body and the transverse mother track or between the front longitudinal wheels of the vehicle body and the longitudinal sub-track, and a1 is the acceleration of the high-speed pallet four-way shuttle vehicle;

[0008] If C T ≤1, it indicates that the high-speed pallet four-way shuttle vehicle will overturn during the startup acceleration phase, and the high-speed pallet four-way shuttle vehicle is prohibited from running; if C T >1, it indicates that the high-speed pallet four-way shuttle is unlikely to overturn during the startup and acceleration phase, and the high-speed pallet four-way shuttle continues to operate;

[0009] 2) During the braking and deceleration phase of the high-speed pallet four-way shuttle, the anti-overturning coefficient C is calculated using the following formula: T :

[0010]

[0011] Where a2 is the deceleration of the high-speed pallet four-way shuttle, F3 and F4 are the contact forces between the rear transverse wheels and the transverse parent track, or between the rear longitudinal wheels and the longitudinal parent track.

[0012] Preferably, for the condition where the pallet cargo is offset front to back when the trolley is running transversely, the distance l2 between the center of mass O2 of the pallet cargo and the rear transverse wheel of the vehicle body is calculated using the following formula:

[0013] l2=l′2-l3

[0014]

[0015] Where, l3 is the vertical distance between sensor 3, sensor 4 and the rear transverse wheel of the vehicle body; l′2 is the vertical distance between the center of mass O2 of the pallet cargo and the line connecting sensor 3 and sensor 4; lc is the distance between sensor 2 and sensor 4; F′1, F′2, F′3 and F′4 are the loads measured by sensor 1, sensor 2, sensor 3 and sensor 4 respectively;

[0016] For the left-right offset working condition of the pallet cargo in the longitudinal operation of the trolley, the distance l2 between the center of mass O2 of the pallet cargo and the rear longitudinal wheel of the vehicle body is calculated using the following formula:

[0017] l2=l″2-l′3

[0018]

[0019] Where, l′3 is the vertical distance between sensor 2, sensor 4 and the line connecting the rear longitudinal wheel of the vehicle body; l″2 is the vertical distance between the center point O2 of the pallet cargo and the line connecting sensor 2 and sensor 4; l s is the distance between sensor 3 and sensor 4; F′1, F′2, F′3 and F′4 are measured by sensor 1, sensor 2, sensor 3 and sensor 4 respectively.

[0020] Preferably, the anti-overturning coefficient C T The larger the value of , the better the anti-overturning performance of the high-speed pallet four-way shuttle vehicle.

[0021] Preferably, the anti-overturning coefficient value C is given T It provides a reference for the cargo stacking height, the friction coefficient between the cargo and the body of the high-speed pallet-type four-way shuttle, and the acceleration and deceleration of the high-speed pallet-type four-way shuttle during the start and stop phases.

[0022] Preferably, according to the anti-overturning coefficient value C T During the operation of high-speed pallet four-way shuttle vehicles, it provides a reference for limiting the offset range of goods and provides early warning judgment for the safety of the operation of high-speed pallet four-way shuttle vehicles.

[0023] Aiming at the possible impact of cargo offset on the high-speed motion stability of ASRV, the present invention considers factors such as the friction between the pallet and the frame on the vehicle body, the center of gravity of the stacked pallet cargo, and the motion parameters and structural parameters of the ASRV, and proposes an evaluation scheme for the safety of warehouse cargo handling.

[0024] Compared with the existing technology, the innovation of the present invention lies in: comprehensively considering the loading parameters of pallet cargo, the friction coefficient between the pallet cargo and the frame on the ASRV body, and the motion performance of the ASRV, an evaluation method and indicators for the motion stability of a high-speed pallet-type four-way shuttle are proposed; in the planning and design stage, an effective reference is provided for the motion control of the ASRV, the offset range limitation of the cargo, and the design and layout of the vehicle body; at the same time, during the vehicle body operation stage, early warning information is provided for the operating status of the ASRV cargo offset working condition. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is the stress analysis of the cargo ASRV during the acceleration phase;

[0026] Figure 2 It is the stress analysis of the cargo ASRV during the deceleration stage;

[0027] Figure 3 Schematic diagram of the installation location of the ASRV upper frame pressure sensor. DETAILED DESCRIPTION

[0028] Below in conjunction with specific embodiment, further set forth the present invention.Should be understood that these embodiments are only used to illustrate the present invention and are not used in limiting the scope of the present invention.In addition, should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall equally within the scope limited by the appended claims of the application.

[0029] The present invention provides a method for evaluating the motion stability of a high-speed four-way shuttle considering cargo bias, comprising the following:

[0030] To address the problem of cargo overturning during ASRV start-up and stop operations due to cargo offset, this paper proposes a method for evaluating the high-speed stability of an ASRV based on the anti-overturning coefficient. Given a certain cargo load and vehicle kinematic performance, the degree of cargo offset is directly proportional to the anti-overturning coefficient. The anti-overturning coefficient can be used as a comprehensive indicator for evaluating the high-speed stability of an ASRV.

[0031] The anti-overturning coefficient is C T The expression is:

[0032] C T =M s / M t

[0033] Where M s M is the sum of the moments of the stabilizing force (restraining overturning) exerted on the vehicle body on the overturning line; t It is the sum of the moments of the overturning force on the vehicle body about the overturning line.

[0034] When the ASRV starts running at acceleration a, its force analysis is as follows: Figure 1 As shown in the figure, it is easy to roll over backwards around the line connecting the contact points between the two rear wheels and the track. At this time, the calculation expression of the anti-rollover coefficient of the vehicle body is:

[0035]

[0036] Where G h is the weight of the pallet cargo, G v is the weight of the ASRV, l1 and l2 are the distances between the center of mass of the vehicle body O1 and the center of mass of the pallet cargo O2 and the rear transverse wheel or rear longitudinal wheel of the vehicle body, respectively. v F is the distance between the front and rear transverse wheels or the front and rear longitudinal wheels of the vehicle body. a is the friction between the pallet cargo and the top surface of the upper frame, h v is the thickness of the vehicle body, h1 is the height of the center of gravity of the ASRV vehicle body, h2 is the height of the center of gravity of the pallet cargo, and F1 and F2 are the contact forces between the front transverse wheel or front longitudinal wheel of the vehicle body and the track.

[0037] The front and rear offset of pallet cargo can cause the ASRV to overturn during operation on the horizontal mother track. Similarly, the left and right offset of pallet cargo can cause the ASRV to overturn during operation on the longitudinal sub-track.

[0038] Taking the front-to-back offset condition of pallet cargo (i.e., ASRV running on the transverse mother track) as an example, in the above formula, F1 and F2 are the vertical loads between the front transverse wheel 6 of the vehicle body and the transverse mother track when the cargo is offset backward, then: F1+F2=(G v +G h )l2 / (2l v ).

[0039] Taking the left-right offset condition of pallet cargo (i.e., ASRV running on the longitudinal sub-track) as an example, in the above formula, F1 and F2 are the vertical loads between the front longitudinal wheel 8 of the vehicle body and the longitudinal sub-track when the cargo is offset to the right, and the calculation method is the same as above.

[0040] When the ASRV is running at a braking deceleration rate a, its force analysis is as follows: Figure 1 As shown in the figure, it is easy to roll forward around the line connecting the contact points between the two front wheels and the track. The calculation formula for the anti-rollover coefficient of the vehicle body is:

[0041]

[0042] Among them, when the ASRV body structure design is completed, the parameter G v 、l v 、l1、h v, h1 are constants, l2 is used to indirectly measure the horizontal offset of the center of gravity of the pallet cargo, F3 and F4 are the contact forces between the rear transverse wheels of the vehicle body and the transverse mother track or between the rear longitudinal wheels of the vehicle body and the longitudinal sub-track.

[0043] For the front-to-back offset condition of pallet cargo, F3 and F4 are the vertical loads between the rear transverse wheel 5 and the transverse parent track when the cargo is offset forward, then: F3+F4=(G v +G h )(l v -l2) / (2l v ).

[0044] For the left-right offset working condition of pallet cargo (i.e., ASRV running on the longitudinal sub-track), in the above formula, F3 and F4 are the vertical loads between the rear longitudinal wheel 7 of the vehicle body and the longitudinal sub-track when the cargo is offset to the left, and the calculation method is the same as above.

[0045] In the above formula, F a =f h *G h , f h is the friction coefficient between the pallet cargo and the upper frame.

[0046] In the above formula, for the condition where the trolley is running horizontally and the pallet cargo is offset forward and backward, l2 is calculated using the following formula:

[0047] l2=l′2-l3

[0048]

[0049] Where, l3 is the vertical distance between sensor 3, sensor 4 and the rear transverse wheel of the vehicle body; l′2 is the vertical distance between the center of mass O2 of the pallet cargo and the line connecting sensor 3 and sensor 4; l c is the distance between sensor 2 and sensor 4; F′1, F′2, F′3 and F′4 are measured by sensor 1, sensor 2, sensor 3 and sensor 4 respectively.

[0050] The distance of the center of gravity of the pallet cargo is |l v / 2-l2|, when l v When / 2-l2 is positive, it means that the center of gravity of the pallet cargo is shifted forward, otherwise it means that the center of gravity is shifted backward.

[0051] For the left and right offset working condition of the trolley running longitudinally with pallet cargo, l2 is calculated using the following formula:

[0052] l2=l″2-l′3

[0053]

[0054] Where, l′3 is the vertical distance between sensor 2, sensor 4 and the line connecting the rear longitudinal wheel of the vehicle body; l″2 is the vertical distance between the center point O2 of the pallet cargo and the line connecting sensor 2 and sensor 4; l s is the distance between sensor 3 and sensor 4; F′1, F′2, F′3 and F′4 are measured by sensor 1, sensor 2, sensor 3 and sensor 4 respectively.

[0055] The distance of the center of gravity of the pallet cargo is |l v / 2-l2|, when l v When / 2-l2 is positive, it means that the center of gravity of the pallet cargo is shifted to the left, otherwise it means that the center of gravity is shifted to the right.

[0056] According to the obtained parameters and the formula given above, the anti-overturning coefficient value C corresponding to the start-stop stage of the ASRV under the bias condition can be determined. T If the anti-overturning coefficient value C T ≤1, it means that the ASRV will overturn during the start-stop process, and the ASRV should be prohibited from running. At the same time, the anti-overturning coefficient C T The larger the value, the better the anti-overturning performance of the ASRV.

[0057] By giving the value of the overturning coefficient C T It can provide a reference for the cargo stacking height, the friction coefficient between the cargo and the upper vehicle body, and the acceleration and deceleration during the start and stop phases of the ASRV. T During the vehicle operation phase, this provides a reference for limiting the offset range of cargo and provides early warning judgments for the safety of ASRV operation. At the same time, during the vehicle design phase, it provides an effective reference for vehicle structure design and layout, and provides an evaluation plan for the design and selection of cargo parameters.

Claims

1. A method for evaluating the motion stability of a high-speed pallet-type four-way shuttle vehicle, wherein the high-speed pallet-type four-way shuttle vehicle runs on a transverse mother track and a longitudinal sub-track. The vehicle body of the high-speed pallet-type four-way shuttle vehicle is provided with front transverse wheels and rear transverse wheels that cooperate with the transverse mother track, and front longitudinal wheels and rear longitudinal wheels that cooperate with the longitudinal sub-track. In addition, the vehicle body is provided with sensors 1, 2, 3, and 4 for measuring the load of pallet cargo. Sensors 1, 2, 3, and 4 are arranged at four angles, and in the left-right direction, sensor 1 and sensor 2 are on the same side, and sensor 3 and sensor 4 are on the same side. The method is characterized in that: The motion stability evaluation method comprises the following steps: 1) During the startup and acceleration phase of a high-speed pallet four-way shuttle, the anti-overturning coefficient C is calculated using the following formula: T : Where G h is the weight of the pallet cargo, G v is the weight of the high-speed pallet four-way shuttle vehicle, l1 and l2 are the distances between the center of mass O1 of the vehicle body and the center of mass O2 of the pallet cargo and the rear transverse wheel or the rear longitudinal wheel of the vehicle body, respectively. v F is the distance between the front and rear transverse wheels or the front and rear longitudinal wheels of the vehicle body, a is the friction between the pallet cargo and the top surface of the upper frame, h v is the vehicle body thickness, h1 is the height of the center of gravity of the high-speed pallet four-way shuttle vehicle, h2 is the height of the center of gravity of the pallet cargo, F1 and F2 are the contact forces between the front transverse wheels of the vehicle body and the transverse mother track or between the front longitudinal wheels of the vehicle body and the longitudinal sub-track, and a1 is the acceleration of the high-speed pallet four-way shuttle vehicle; If C T ≤1, it indicates that the high-speed pallet four-way shuttle will overturn during the startup acceleration phase, and the high-speed pallet four-way shuttle is prohibited from running; if C T >1, it indicates that the high-speed pallet four-way shuttle is unlikely to overturn during the startup and acceleration phase, and the high-speed pallet four-way shuttle continues to operate; 2) During the braking and deceleration phase of the high-speed pallet four-way shuttle, the anti-overturning coefficient C is calculated using the following formula: T : Where a2 is the deceleration of the high-speed pallet four-way shuttle, F3 and F4 are the contact forces between the rear transverse wheels and the transverse parent track or between the rear longitudinal wheels and the longitudinal parent track; For the case where the trolley is running horizontally and the pallet cargo is offset front to back, the distance l2 between the center of mass O2 of the pallet cargo and the rear transverse wheel of the vehicle body is calculated using the following formula: l2＝l′2-l3 Where, l3 is the vertical distance between sensor 3, sensor 4 and the rear transverse wheel of the vehicle body; l′2 is the vertical distance between the center of mass O2 of the pallet cargo and the line connecting sensor 3 and sensor 4; l c is the distance between sensor 2 and sensor 4; F1′, F2′, F3′ and F4′ are the loads measured by sensor 1, sensor 2, sensor 3 and sensor 4 respectively; For the left-right offset working condition of the pallet cargo in the longitudinal operation of the trolley, the distance l2 between the center of mass O2 of the pallet cargo and the rear longitudinal wheel of the vehicle body is calculated using the following formula: l2＝l″2-l′3 Where, l′3 is the vertical distance between sensor 2, sensor 4 and the line connecting the rear longitudinal wheel of the vehicle body; l″2 is the vertical distance between the center point O2 of the pallet cargo and the line connecting sensor 2 and sensor 4; l s is the distance between sensor 3 and sensor 4; F1′, F2′, F3′ and F4′ are measured by sensor 1, sensor 2, sensor 3 and sensor 4 respectively.

2. A method for evaluating the motion stability of a high-speed pallet-type four-way shuttle according to claim 1, characterized in that: The anti-overturning coefficient C T The larger the value of , the better the anti-overturning performance of the high-speed pallet four-way shuttle vehicle.

3. A method for evaluating the motion stability of a high-speed pallet-type four-way shuttle according to claim 1, characterized in that: The overturning resistance coefficient value C given by T It provides a reference for the cargo stacking height, the friction coefficient between the cargo and the body of the high-speed pallet-type four-way shuttle, and the acceleration and deceleration of the high-speed pallet-type four-way shuttle during the start and stop phases.

4. A method for evaluating the motion stability of a high-speed pallet-type four-way shuttle according to claim 1, characterized in that: According to the anti-overturning coefficient value C T During the operation of high-speed pallet four-way shuttle vehicles, it provides a reference for limiting the offset range of goods and provides early warning judgment for the safety of the operation of high-speed pallet four-way shuttle vehicles.

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