Container cargo lifting platform truck and control method

Abstract

The invention discloses a container cargo lifting platform truck and a control method, the container cargo lifting platform truck comprises a chassis system, the chassis system comprises a plurality of supporting legs capable of independently lifting and a sensing unit, and the sensing unit is used for obtaining inclination angle data of the chassis system and height and pressure data of each supporting leg; the working platform is arranged on the chassis system; the lifting system is used for connecting the chassis system with the working platform and driving the working platform to lift; the electric control system comprises a controller; and a hydraulic system. The controller is configured to execute the following steps: calculating the target height of each supporting leg based on the acquired inclination angle data in combination with a preset target ground clearance and the wheelbase and the wheelbase of the chassis system; and according to the calculated target height of each supporting leg, an instruction for adjusting each supporting leg is sent to a hydraulic system. The container cargo lifting platform truck and the control method can adapt to complex terrains, and safe, efficient and accurate operation is achieved.

Description

Technical Field

[0001] This invention relates to a container cargo lifting platform vehicle and its control method, belonging to the technical field of aviation ground support equipment. Background Technology

[0002] At air cargo terminals, containerized cargo needs to be frequently transferred and loaded / unloaded between ground transport vehicles and aircraft cargo holds. While traditional lifting platform trucks possess lifting capabilities, they generally suffer from the following problems: First, their fixed ground clearance results in poor maneuverability, making rapid relocation difficult in complex airport ground conditions. Second, their platform leveling capabilities are insufficient or entirely reliant on manual adjustment, leading to poor stability and safety hazards when operating on sloping ground, particularly the risk of partial support (where a support leg is not fully supported, causing the equipment to tip over). Third, in situations requiring coordinated lifting of the main platform and docking bridge platform, the lack of precise synchronization control leads to asynchronous lifting, potentially causing cargo jamming, uneven stress on the equipment structure, or even damage, resulting in low operational efficiency.

[0003] Therefore, in order to solve the above problems, there is an urgent need for a container cargo lifting platform vehicle and control method that can adapt to complex terrain and achieve safe, efficient and precise operation. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a container cargo lifting platform vehicle and control method that can adapt to complex terrain and achieve safe, efficient and precise operation.

[0005] To achieve the above objectives / to solve the above technical problems, the present invention is implemented using the following technical solution: In a first aspect, the present invention provides a container cargo lifting platform vehicle, comprising: The chassis system includes multiple independently adjustable outriggers and sensing units. The sensing units are used to acquire tilt data of the chassis system and height and pressure data of each outrigger. The work platform, mounted on the chassis system, is used to carry goods; A lifting system is used to connect the chassis system and the work platform, and to drive the work platform to lift and lower. Electrical control system, including controller; and, A hydraulic system, connected to the lifting system and the outriggers, is controlled by the electronic control system; The controller is configured to execute: Before operation, based on the acquired tilt angle data, the target height of each outrigger is calculated in combination with the preset target ground clearance and the wheelbase and track width of the chassis system. Based on the calculated target height of each outrigger, a command to adjust each outrigger is sent to the hydraulic system; During operation, the system continuously acquires data on the height and pressure of the outriggers. When the height of a certain outrigger does not meet the target height or the pressure is lower than the preset threshold, the system sends a command to the hydraulic system to adjust the outrigger until the outrigger reaches the target height or the pressure reaches the preset threshold.

[0006] Furthermore, the target height of each outrigger is calculated using the following formula: -[ ]+[ ]; -[ ]-[ ]; +[ ]+[ ]; +[ ]-[ ]; In the formula, The target height for the left front support leg. The target height for the right front support leg. The target height for the left rear support leg. The target height for the right rear support leg. Where W is the target ground clearance, L is the wheelbase, and L is the track width. The lateral tilt angle, This is the longitudinal tilt angle.

[0007] Furthermore, the working platform includes a main platform and a bridge platform, and each of the main platform and the bridge platform is equipped with a height sensor for acquiring its respective height, and the height sensor is signal-connected to the controller.

[0008] Furthermore, the controller is also configured to perform: Obtain the real-time height of the main platform and bridge platform; When the two platforms are rising or falling synchronously, if the height difference between the two platforms exceeds the set range, reduce the rising speed of the bridge platform or the falling speed of the main platform until the height difference between the two platforms returns to the allowable range, and then resume synchronous rising or falling.

[0009] Furthermore, the hydraulic system includes an electro-hydraulic proportional valve controlled by the electronic control system, which receives electrical signals from the controller and proportionally adjusts the hydraulic oil flow to drive the outrigger cylinders and the lifting system.

[0010] In a second aspect, the present invention provides a control method for the container cargo lifting platform vehicle described in the first aspect, comprising: Before operation, obtain the tilt angle data of the chassis system, and calculate the target height of each outrigger by combining the preset target ground clearance and the wheelbase and track width of the chassis system. Based on the calculated target height of each outrigger, a command to adjust each outrigger is sent to the hydraulic system; During operation, the system continuously acquires data on the height and pressure of the outriggers. When the height of a certain outrigger does not meet the target height or the pressure is lower than the preset threshold, the system sends a command to the hydraulic system to adjust the outrigger until the outrigger reaches the target height or the pressure reaches the preset threshold.

[0011] Furthermore, the target height of each outrigger is calculated using the following formula: -[ ]+[ ]; -[ ]-[ ]; +[ ]+[ ]; +[ ]-[ ]; In the formula, The target height for the left front support leg. The target height for the right front support leg. The target height for the left rear support leg. The target height for the right rear support leg. Where W is the target ground clearance, L is the wheelbase, and L is the track width. The lateral tilt angle, This is the longitudinal tilt angle.

[0012] Furthermore, the method also includes: Obtain the real-time height of the main platform and bridge platform; When the two platforms are rising or falling synchronously, if the height difference between the two platforms exceeds the set range, reduce the rising speed of the bridge platform or the falling speed of the main platform until the height difference between the two platforms returns to the allowable range, and then resume synchronous rising or falling.

[0013] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: The container cargo lifting platform vehicle and control method provided by this invention calculates the global ground clearance target into independent height commands for each outrigger. The controller controls the movement of each outrigger according to the independent height commands. The displacement sensors on the outriggers provide real-time feedback of height information, which is compared with the target height to form a closed-loop control, ensuring a constant ground clearance. This allows the system to adapt to complex terrain and achieve safe, efficient, and precise operation. Attached Figure Description

[0014] Figure 1 This is a structural schematic diagram of the container cargo lifting platform vehicle provided by the present invention; Figure 2 yes Figure 1 A schematic diagram of the mid-chassis system lowering to its minimum height during operation; Figure 3 yes Figure 1 A schematic diagram of the mid-chassis system raised to its maximum height during operation; Figure 4 This is a schematic diagram of the chassis lifting outrigger structure; Figure 5 This is a schematic diagram of automatic leveling and operation on a sloping site; Figure 6 This is a diagram of the synchronous lifting control strategy.

[0015] In the diagram: 1. Chassis system; 2. Lifting system; 3. Working platform; 4. Hydraulic system; 5. Electrical control system; 6. Power system. Detailed Implementation

[0016] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0017] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are used only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0018] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances. Example

[0019] like Figure 1 As shown, this embodiment provides a container cargo lifting platform vehicle, including: The chassis system 1 includes multiple independently adjustable outriggers and sensing units. The sensing units are used to acquire tilt data of the chassis system 1 and height and pressure data of each outrigger. The working platform 3 is mounted on the chassis system 1 and is used to carry goods; Lifting system 2 is used to connect the chassis system 1 and the work platform 3, and to drive the work platform 3 to lift. The electronic control system 5 includes a controller; and, Hydraulic system 4 is connected to the lifting system 2 and the outriggers, and is controlled by the electronic control system 5; The controller is configured to execute: Before operation, based on the acquired tilt angle data, the target height of each outrigger is calculated in combination with the preset target ground clearance and the wheelbase and track width of the chassis system 1. Based on the calculated target height of each outrigger, a command to adjust each outrigger is sent to the hydraulic system 4. During operation, the system continuously acquires data on the height and pressure of the outriggers. When the height of a certain outrigger does not meet the target height or the pressure is lower than the preset threshold, the system sends an instruction to the hydraulic system 4 to adjust the outrigger until the outrigger reaches the target height or the pressure reaches the preset threshold.

[0020] The chassis system 1 is also equipped with a power system 6, which provides power to the chassis system 1. The chassis system 1 carries and powers various functional modules, enabling functions such as walking, steering, and braking. The ground clearance of the chassis is adjusted via lifting outriggers. During lifting operations... Figure 2 As shown, the chassis is lowered to its lowest position, with the main platform's minimum height being 480mm; when driving... Figure 3 As shown, with the chassis raised to its highest position, the minimum ground clearance is 200mm, ensuring the machine's passability. The chassis lifting is achieved by a hydraulic cylinder driving a telescopic sleeve to raise and lower the outriggers. Figure 4As shown. The lifting cylinder features a heavy-duty design and works in conjunction with the hydraulic system 4 to provide strong support. This chassis lifting technology allows for adjustable minimum ground clearance (e.g., ≥200mm), significantly improving passability on uneven terrain.

[0021] The core of the electrical control system is a PLC controller. This system integrates three core control functions: chassis lifting control, automatic leveling control, and dual-platform synchronous lifting control.

[0022] When implementing chassis lifting control, the operator sets the target ground clearance. The controller receives signals from the tilt sensor mounted on the chassis to acquire the chassis's longitudinal tilt angle in real time. and lateral tilt angle The system, based on the chassis's inherent geometric parameters of wheelbase W and track L, calculates the target height required for each outrigger to achieve the target ground clearance on inclined ground using trigonometric functions. Specifically, it uses the formula... = ( , , Calculations are performed using W and L, where The target height of the i-th outrigger is represented by a variable, thus converting the global ground clearance target into independent height commands for each outrigger. Subsequently, the controller drives the lifting cylinders by controlling the electro-hydraulic proportional valves of each outrigger. Displacement sensors on the cylinders provide real-time height feedback, which is compared with the target height to form a closed-loop control system, ensuring a constant ground clearance and automatically compensating for uneven ground.

[0023] like Figure 5 The diagram shown illustrates automatic leveling and operation on an inclined surface. To achieve automatic leveling control, the system employs a combined static and dynamic leveling strategy. During static leveling, before lifting, tilt sensors on the chassis and platform detect the ground tilt. The controller quickly calculates and instructs each outrigger to extend by the corresponding length (consistent with the chassis lifting control logic), ensuring the platform is nearly level from the starting position and initially guaranteeing force on each outrigger. During operation, this is the dynamic leveling phase. The platform tilt sensor continuously monitors the platform's levelness, and the pressure sensors on each outrigger cylinder monitor the support pressure in real time. When platform tilt is detected or the pressure on a particular outrigger falls below a set threshold, it is identified as a "false outrigger." The controller immediately issues a command to control the electro-hydraulic proportional valve of the corresponding outrigger to compensate by extending or retracting until the platform is level and all outrigger pressures are normal, effectively eliminating safety hazards.

[0024] The specific control logic for chassis lifting and static leveling is as follows: Control objectives: such as Figure 5As shown, on a sloped surface, by independently adjusting the height of the four outriggers, the entire chassis plane can maintain a preset posture in space, usually horizontal, and eventually achieve a constant target ground clearance.

[0025] The core idea is to treat the chassis as a rigid plane. By measuring the angle of inclination of this plane relative to the horizontal plane, the height difference that each outrigger needs to compensate for in order to restore the plane to horizontality is calculated.

[0026] Calculation process: We first establish a simplified mathematical model. We consider the chassis as a rectangular rigid body, with the four legs located at the four corner points. Let: The lateral distance between the centers of the two outriggers of the front axle.

[0027] The lateral distance between the centers of the two rear axle support legs is usually... = = L.

[0028] W: The distance between the front and rear axles.

[0029] The target ground clearance set by the operator is the vertical distance from a fixed reference point on the chassis, such as the chassis beam, to the ground.

[0030] θx: The lateral tilt angle of the chassis around the vehicle's direction of travel, measured by a tilt sensor, with right tilt being positive.

[0031] θy: The longitudinal tilt angle of the chassis around the vehicle's lateral side, measured by a tilt sensor, with the front higher than the rear as positive.

[0032] (1) Calculate the horizontal compensation height of each outrigger. Longitudinal compensation based on pitch angle θy: Due to the pitch angle, the front and rear axles require different heights. Assuming all outriggers are initially at the same height, the height difference between the front and rear axles required to level the chassis is: = W ; because It is usually very small and can be approximated as ≈ W y (radians).

[0033] For the two outriggers on the front axle, the base height needs to be reduced by [amount missing]. / 2.

[0034] For the two outriggers on the rear axle, an additional height needs to be added to the base height. / 2.

[0035] Lateral compensation based on roll angle θx: Due to the roll angle, the required height differs between the left and right sides. The required height difference between the left and right sides is: = L sin(θx) ≈ L θx (radians).

[0036] For the two outriggers on the left, the height needs to be increased by adding to the base height. / 2.

[0037] For the two outriggers on the right side, the following needs to be subtracted from the reference height. / 2.

[0038] Comprehensive calculation of the target height of each outrigger Set a reference height It is usually equal to the target's ground clearance. Add a fixed offset determined by the chassis structure For the sake of simplicity, we can assume that... ≈.

[0039] Therefore, the final target height of the four outriggers is calculated as follows: = - ( / 2) + ( / 2); = - ( / 2) - ( / 2); = + ( / 2) + ( / 2); = + ( / 2) - ( / 2);; = + ( / 2) - ( / 2); Right now: -[ ]+[ ]; -[ ]-[ ]; +[ ]+[ ]; +[ ]-[ ]; In the formula, The target height for the left front support leg. The target height for the right front support leg. The target height for the left rear support leg. The target height for the right rear support leg. Where W is the target ground clearance, L is the wheelbase, and L is the track width. The lateral tilt angle, longitudinal tilt angle The following example illustrates this concept, where W = 3m and L = 2m. =200mm, the measured ground inclination angle is = 1° (0.01745 rad), = 0.5° (0.00873 rad).

[0040] ≈ 3 0.01745 = 0.05235 m = 52.35 mm; ≈ 2 0.00873 = 0.01746 m = 17.46 mm; The target height for each outrigger is then: = 200 - (52.35 / 2) + (17.46 / 2) = 200 - 26.18 + 8.73 = 182.55 mm; = 200 - (52.35 / 2) - (17.46 / 2) = 200 - 26.18 - 8.73 = 165.09 mm; = 200 + (52.35 / 2) + (17.46 / 2) = 200 + 26.18 + 8.73 = 234.91 mm; = 200 + (52.35 / 2) - (17.46 / 2) = 200 + 26.18 - 8.73 = 217.45 mm; After the calculation is completed, the controller will drive each outrigger so that the height value fed back by its displacement sensor reaches the calculated value.

[0041] The working platform includes a main platform and a bridge platform. Each of the main platform and the bridge platform is equipped with a height sensor for acquiring its own height. The height sensor is connected to the controller via a signal connection.

[0042] The controller is also configured to perform: Obtain the real-time height of the main platform and bridge platform; When the two platforms are rising or falling synchronously, if the height difference between the two platforms exceeds the set range, reduce the rising speed of the bridge platform or the falling speed of the main platform until the height difference between the two platforms returns to the allowable range, and then resume synchronous rising or falling.

[0043] Specifically, the system acquires initial height values ​​using height sensors installed on both the main platform and the bridge platform. During synchronous lifting, the bridge platform is on top, and the main platform follows the bridge platform's ascent. When the height difference between the two platforms becomes too large, the bridge platform slows down or stops rising, while the main platform maintains its ascent speed until the height difference between the two platforms enters the allowable error range, and then they rise and fall synchronously. The synchronous descent process is similar, with the main platform below and the bridge platform above. The current of the descent solenoid valves for both platforms changes with the opening of the lifting handle. When the height difference between the two platforms becomes too large, the main platform slows down or stops falling, while the bridge platform maintains its descent speed until the height difference between the two platforms enters the set range, and then both platforms descend together. Once the height difference between the two platforms exceeds the set value, PID feedback adjustment is activated; otherwise, both platforms move according to the handle opening. See the logic flowchart below. Figure 6 As shown.

[0044] The hydraulic system 4 includes an electro-hydraulic proportional valve controlled by the electronic control system 5. This valve receives electrical signals from the controller and proportionally adjusts the hydraulic oil flow to drive the outrigger cylinders and the lifting system 2. The hydraulic system 4 adopts a closed design, with a high-precision electro-hydraulic proportional valve as the core control element, ensuring stable and accurate control. The hydraulic system 4 also includes safety devices such as hydraulic locks and balance valves, as well as redundant protections such as mechanical locking nuts. These are standard configurations in existing hydraulic systems and will not be described in detail here. Example

[0045] This embodiment provides a control method for a container cargo lifting platform vehicle provided in Embodiment 1, comprising: Before operation, obtain the tilt angle data of chassis system 1, and calculate the target height of each outrigger by combining the preset target ground clearance and the wheelbase and track of chassis system 1. Based on the calculated target height of each outrigger, a command to adjust each outrigger is sent to the hydraulic system 4. During operation, the system continuously acquires data on the height and pressure of the outriggers. When the height of a certain outrigger does not meet the target height or the pressure is lower than the preset threshold, the system sends an instruction to the hydraulic system 4 to adjust the outrigger until the outrigger reaches the target height or the pressure reaches the preset threshold.

[0046] The target height of each outrigger is calculated using the following formula: -[ ]+[ ]; -[ ]-[ ]; +[ ]+[ ]; +[ ]-[ ]; In the formula, The target height for the left front support leg. The target height for the right front support leg. The target height for the left rear support leg. The target height for the right rear support leg. Where W is the target ground clearance, L is the wheelbase, and L is the track width. The lateral tilt angle, This is the longitudinal tilt angle.

[0047] The method further includes: Obtain the real-time height of the main platform and bridge platform; When the two platforms are rising or falling synchronously, if the height difference between the two platforms exceeds the set range, reduce the rising speed of the bridge platform or the falling speed of the main platform until the height difference between the two platforms returns to the allowable range, and then resume synchronous rising or falling.

[0048] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A lift platform truck for unitized cargo, characterized in that The application relates to a method and a device for controlling a lifting system of a working platform. The device comprises: a chassis system (1) comprising a plurality of independently liftable legs and a sensing unit for obtaining inclination data of the chassis system (1) and height and pressure data of each leg; a working platform (3) arranged above the chassis system (1) for carrying goods; a lifting system (2) for connecting the chassis system (1) and the working platform (3) and for driving the working platform (3) to lift; an electric control system (5) comprising a controller; and a hydraulic system (4) connected with the lifting system (2) and the legs and controlled by the electric control system (5); wherein the controller is configured to perform: before work, calculating target heights of the legs based on the obtained inclination data, in combination with a preset target ground clearance and wheelbase and track of the chassis system (1); sending instructions for adjusting the legs to the hydraulic system (4) according to the calculated target heights of the legs; 2. The lift platform truck of claim 1, wherein, during work, continuously obtaining the height and pressure data of the legs, and when the height of a certain leg does not conform to the target height or the pressure is lower than a preset threshold, sending instructions for adjusting the leg to the hydraulic system (4) until the leg reaches the target height or the pressure reaches the preset threshold. -[ ]+[ ]； -[ ]-[ ]； +[ ]+[ ]； +[ ]-[ ]； wherein Hleft is the target height of the left front leg, Hright is the target height of the right front leg, Hleft is the target height of the left front leg, Hright is the target height of the right front leg, W is the wheelbase, and L is the track width, is the target roll angle, is the target pitch angle.

3. The lift platform truck of claim 1, wherein, The target height of each leg is calculated by the following formula:

4. The lift platform truck of claim 3, wherein, The working platform comprises a main platform and a bridge platform, and height sensors for obtaining the heights of the main platform and the bridge platform are arranged on the main platform and the bridge platform respectively, and the height sensors are signal-connected with the controller. The controller is further configured to perform: obtaining real-time heights of the main platform and the bridge platform; 5. The lift platform truck of claim 1, wherein, when the two platforms are synchronously lifted or lowered, if the height difference between the two platforms exceeds a set range, the lifting speed of the bridge platform is reduced or the lowering speed of the main platform is reduced until the height difference between the two platforms recovers to a permissible range, and then the synchronous lifting or lowering is resumed.

6. A control method for the container lift platform truck according to any one of claims 1-5, characterized in that The hydraulic system (4) comprises an electro-hydraulic proportional valve controlled by the electric control system (5) and used for receiving the electric signal of the controller and proportionally adjusting the flow of hydraulic oil to drive the leg oil cylinder and the lifting system (2). The method comprises: before work, obtaining inclination data of the chassis system (1), and calculating target heights of the legs in combination with a preset target ground clearance and wheelbase and track of the chassis system (1); sending instructions for adjusting the legs to the hydraulic system (4) according to the calculated target heights of the legs; 7. The control method according to claim 6, characterized by during work, continuously obtaining the height and pressure data of the legs, and when the height of a certain leg does not conform to the target height or the pressure is lower than a preset threshold, sending instructions for adjusting the leg to the hydraulic system (4) until the leg reaches the target height or the pressure reaches the preset threshold. -[ ]+[ ]； -[ ]-[ ]； +[ ]+[ ]； +[ ]-[ ]； wherein Hleftfrontis the target height of the left front leg, Hrightfrontis the target height of the right front leg, Hleftrearis the target height of the left rear leg, Hrightrearis the target height of the right rear leg, is the target ground clearance, W is the wheelbase, and L is the track width, is the target roll angle, is the target pitch angle.

8. The control method according to claim 7, characterized by, The target height of each leg is calculated by the following formula: The method further comprises: obtaining real-time heights of the main platform and the bridge platform; when the two platforms are synchronously lifted or lowered, if the height difference between the two platforms exceeds a set range, the lifting speed of the bridge platform is reduced or the lowering speed of the main platform is reduced until the height difference between the two platforms recovers to a permissible range, and then the synchronous lifting or lowering is resumed.

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