Loader drive control method and loader

Abstract

This invention discloses a drive control method for a loader and a loader. The drive control method includes: real-time detection of the operating status of each battery branch; when a power-down fault is detected in at least one battery branch, if the total output power of the remaining normal battery branches is greater than or equal to a first power threshold, controlling both the drive motor and the hydraulic motor for the current working condition to operate at normal power; if a second power threshold is less than or equal to the total output power of the remaining normal battery branches and less than the first power threshold, controlling the drive motor for the current working condition to operate at normal power, and simultaneously controlling the hydraulic motor for the current working condition to operate in a power-limited working mode; if the total output power of the remaining normal battery branches is less than the second power threshold, controlling the hydraulic motor to stop running and the drive motor to run.

Description

Technical Field

[0001] This invention relates to the field of loader technology, and in particular to a drive control method for a loader and a loader. Background Technology

[0002] The development of new energy in the construction machinery industry is rapid, especially in high-end mining operations, which have created a zero-carbon emission requirement for ultra-large tonnage mining loaders. Currently, most ultra-large tonnage loaders use a power architecture where an internal combustion engine drives a generator set to power a distributed wheel-side electric drive system, making it difficult to achieve zero carbon emissions.

[0003] To meet range requirements, ultra-heavy-tonnage loaders are typically equipped with large-capacity battery systems. Currently, most pure electric loaders use a single battery pack as their power source. This single-battery-pack solution presents challenges in designing and developing large-capacity single battery packs for ultra-heavy-tonnage mainframes. Furthermore, when a single battery cell or module fails, the only recourse is to limit power or shut down the machine, resulting in high costs for battery pack replacement. Ensuring continuous operation of the loader in the event of battery circuit failures and achieving a reasonable distribution of drive power are pressing technical problems that need to be solved in this field. Summary of the Invention

[0004] The purpose of this invention is to provide a drive control method and a loader, which aims to solve the problems of poor reliability of a single battery pack and inability to continue operation when a fault occurs in the prior art.

[0005] The first aspect of this invention discloses a drive control method for a loader, the loader comprising a multi-branch battery system, a travel motor for driving a traveling device, and a hydraulic motor for driving a hydraulic working device, the multi-branch battery system being composed of multiple battery branches connected in parallel, and the control method comprising: The vehicle controller monitors the operating status of each battery branch in real time; When a power-down fault is detected in at least one battery branch, the vehicle controller obtains the total output power of the remaining normal battery branches and compares the total output power of the remaining normal battery branches with the power threshold of the current operating condition in a graded manner. The power threshold includes a first power threshold and a second power threshold, and the first power threshold > the second power threshold. The vehicle controller executes a hierarchical control strategy based on the comparison results: If the total output power of the remaining normal battery branches is greater than or equal to the first power threshold, then the driving motor and the hydraulic motor that control the current working condition will both operate at normal power. If the second power threshold ≤ the total output power of the remaining normal battery branch < the first power threshold, then control the driving motor of the current working condition to run at normal power, and at the same time control the hydraulic motor of the current working condition to run in power-limited working mode. If the total output power of the remaining normal battery branches is less than the second power threshold, then the hydraulic motor will stop running and the driving motor will run.

[0006] In some embodiments, the first power threshold is the maximum power requirement under normal operating conditions of the current operating condition; the second power threshold is the minimum power requirement under acceptable operating efficiency of the current operating condition.

[0007] In some embodiments, the vehicle controller detects the operating status of each battery branch by detecting the voltage, current, temperature and / or resistance of each battery branch, and determines that the battery branch has a power-off fault when any of the detected parameters exceeds a preset safety range.

[0008] In some embodiments, in the hierarchical control strategy, when the total output power of the remaining normal battery branches is less than a second power threshold, the drive motor is controlled to operate in limp mode, which limits the maximum output power and maximum vehicle speed of the drive motor.

[0009] In some embodiments, the system further includes: working condition identification, which includes the vehicle controller identifying the current working condition of the loader based on the signals from the accelerator pedal, the operating handle, the load cell of the bucket, the first displacement sensor of the lifting cylinder, and the second displacement sensor of the bucket cylinder. The current working condition includes fully loaded working condition, unloaded working condition, material pushing working condition, and driving and relocation working condition.

[0010] In some embodiments, the system further includes: drive motor power distribution, which includes the vehicle controller distributing the output power of the drive motors at the wheel ends of the front and rear frames based on the identified current operating conditions and the obtained vertical load distribution ratio of the front and rear frames.

[0011] In some embodiments, obtaining the vertical load distribution ratio of the front and rear frames of the loader includes: obtaining the boom posture based on the signal from the first displacement sensor of the lifting cylinder, and the vehicle controller obtaining the vertical load distribution ratio of the front and rear frames of the loader based on the current working conditions and the boom posture.

[0012] A second aspect of the present invention discloses a loader, comprising: A multi-branch battery system, comprising multiple battery branches connected in parallel, each battery branch including a battery pack and a DC-DC converter; An electrical load includes multiple first load branches and at least one second load branch, wherein the first load branches include a drive motor driver and a drive motor, and the second load branch includes a hydraulic motor driver and a hydraulic motor; A power distribution unit is connected between the multi-branch battery system and the electrical load; The vehicle controller is electrically connected to the DC-DC converter, the drive motor driver, and the hydraulic motor driver, respectively, and the vehicle controller is configured to execute any of the drive control methods described above.

[0013] In some embodiments, it also includes: A load cell, installed in the bucket, is used to detect the load status of the bucket; The first displacement sensor, mounted on the lifting cylinder, is used to detect the attitude of the boom; The vehicle controller identifies the loader's operating conditions based on signals from the weighing sensor and the first displacement sensor.

[0014] In some embodiments, the vehicle controller is configured to: perform voltage regulation control on each battery branch during normal operation via the DC-DC converter; and perform active equalization charging and discharging on battery branches whose voltage deviates from a preset range.

[0015] The loader drive control method provided by this invention, by setting up a multi-branch battery system composed of multiple parallel battery branches, and by performing graded control based on a comparison of the total output power of the remaining normal battery branches with a first power threshold and a second power threshold when one or more battery branches fail, avoids vehicle shutdown due to insufficient power, thus improving the loader's reliability and continuous operation capability. Compared with the prior art's solution where a single battery pack failure results in shutdown, this solution achieves graded fault-tolerant operation under fault conditions, exhibiting significant reliability advantages.

[0016] Other features and advantages of the invention will become clear from the following detailed description of exemplary embodiments of the invention with reference to the accompanying drawings. Attached Figure Description

[0017] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings: Figure 1 This is a schematic diagram of the electric drive system of the loader according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the drive control system of the loader according to an embodiment of the present invention. Detailed Implementation

[0018] 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. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. 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.

[0019] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0020] In the description of this invention, it should be understood that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0021] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0022] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0023] like Figure 1 As shown, the electric drive system 30 of the loader in this embodiment includes a multi-branch battery system, a travel motor 23 for driving the travel device, and a hydraulic motor 24 for driving the hydraulic working device. The multi-branch battery system consists of multiple battery branches connected in parallel. In the embodiment shown, the battery branch includes a battery pack 11 and a DC-DC converter 12. The electric drive system 30 also includes a battery management system (BMS) that manages each battery pack 11. The loader's travel device is tracks or tires. The loader's hydraulic working device includes a bucket and a boom.

[0024] The drive control methods for loaders include: The vehicle control unit (VCU) monitors the operating status of each battery branch in real time. Specifically, the VCU communicates with the battery management system (BMS) of each battery branch via the CAN bus to obtain operating parameters such as voltage, current, temperature, and insulation resistance of each branch. When any parameter exceeds the preset safety range, such as voltage below the undervoltage threshold, temperature above the overtemperature threshold, or insulation resistance below the insulation threshold, the VCU determines that the battery branch has experienced a power-off fault.

[0025] When a power-down fault is detected in at least one battery branch, the vehicle controller 53 obtains the total output power of the remaining normal battery branches and compares it with the power thresholds of the current operating condition. The power thresholds include a first power threshold and a second power threshold, where the first power threshold > the second power threshold. The VCU obtains the total output power of the remaining normal battery branches, which is the sum of the maximum output power currently available from all fault-free battery branches. The power thresholds of the current operating condition include the first and second power thresholds, which refer to two thresholds set by the loader in the current operating mode. The first power threshold is different under different operating conditions, and the second power threshold is also different under different operating conditions.

[0026] The vehicle controller 53 executes a hierarchical control strategy based on the comparison results: If the total output power of the remaining normal battery branches is greater than or equal to the first power threshold, then the driving motor 23 and the hydraulic motor 24 controlling the current working condition will both operate at normal power; this indicates that the total output power of the remaining normal battery branches is sufficient to meet all the power requirements of the current working condition, and the loader can operate normally without being affected by the fault.

[0027] If the second power threshold ≤ the total output power of the remaining normal battery branches < the first power threshold, then the driving motor 23 for the current operating condition is controlled to operate at normal power, while the hydraulic motor 24 for the current operating condition is controlled to operate in a power-limited mode. In the power-limited mode, the output power of the hydraulic motor is limited to 50%~90% of its rated power, and the specific limit ratio can be dynamically adjusted according to the current operating condition. This condition indicates that the total output power of the remaining normal battery branches is slightly insufficient and cannot simultaneously and fully meet the power requirements of the driving and hydraulic systems, but basic operation can still be maintained. The VCU controls the driving motor to operate at normal power to ensure that the loader's basic driving capability is not affected; at the same time, the output power of the hydraulic motor is appropriately limited so that hydraulic operation can be maintained but efficiency is reduced.

[0028] If the total output power of the remaining normal battery branches is less than the second power threshold, the hydraulic motor 24 is stopped and the travel motor 23 is started. This condition indicates that the total output power of the remaining normal battery branches is severely insufficient to simultaneously maintain travel and hydraulic operation. The VCU controls the hydraulic motor to stop, keeping only the travel motor running to ensure the loader can travel to a maintenance site or a safe location.

[0029] The loader drive control method of this embodiment, by setting up a multi-branch battery system composed of multiple parallel battery branches, and by performing graded control based on a comparison of the total output power of the remaining normal battery branches with a first power threshold and a second power threshold when one or more battery branches fail, avoids vehicle shutdown due to insufficient power, thereby improving the loader's reliability and continuous operation capability. Compared with the prior art's solution where a single battery pack 11 failure results in shutdown, this embodiment achieves graded fault-tolerant operation under fault conditions, exhibiting significant reliability advantages.

[0030] In some embodiments, the first power threshold is the maximum power requirement under normal operating conditions of the current working condition; the second power threshold is the minimum power requirement under acceptable operating efficiency of the current working condition. The first power threshold refers to the maximum power requirement required by the loader under the currently identified working condition. For example, under the fully loaded working condition of a certain model of loader, the maximum power required during the entire normal fully loaded operation is 450kW, then the first power threshold for the fully loaded working condition is 450kW. The second power threshold for the current working condition refers to the minimum total power requirement required by the loader to complete basic tasks under the current working condition, but with reduced operating efficiency (acceptable operating efficiency, such as 70% of the normal operating efficiency). This value reflects the minimum power level at which the loader can complete the task at this operating efficiency. The first and second power thresholds are different under different working conditions. For example, the maximum power requirement under fully loaded working conditions is greater than the maximum power requirement under unloaded working conditions; therefore, the first and second power thresholds under fully loaded working conditions are correspondingly higher than those under unloaded working conditions.

[0031] In some embodiments, the vehicle controller 53 detects the operating status of each battery branch by detecting the voltage, current, temperature, and / or resistance of each battery branch. When any detected parameter exceeds a preset safety range, the battery branch is determined to have a power-down fault. Voltage detection: The VCU obtains the total voltage and individual cell voltage of each battery branch through the BMS. When the total voltage of any battery branch is lower than a preset undervoltage threshold (e.g., 80% of the rated voltage) or higher than an overvoltage threshold (e.g., 120% of the rated voltage), or when the voltage of any individual cell exceeds the safety range, the battery branch is determined to have a power-down fault. Current detection: The VCU obtains the charging and discharging current of each battery branch through the BMS. When the current exceeds a preset overcurrent threshold (e.g., 1.5 times the rated current), the battery branch is determined to have a power-down fault. Temperature detection: The VCU obtains temperature sensor data for each battery branch through the BMS. When any temperature point exceeds a preset temperature threshold (e.g., 60°C), the battery branch is determined to have a power-down fault. When any detected parameter exceeds the preset safety range, the VCU immediately determines that the battery branch has a power-off fault and takes corresponding fault isolation measures, such as controlling the relay of the branch to disconnect and isolating it from the high-voltage bus. This embodiment, through multi-parameter comprehensive detection, can comprehensively and accurately identify various faults in the battery branch, ensuring the reliability and timeliness of fault detection and providing accurate input conditions for subsequent hierarchical control.

[0032] In some embodiments, in the hierarchical control strategy, when the total output power of the remaining normal battery branches is less than a second power threshold, the drive motor 23 is controlled to operate in limp mode. Limp mode limits the maximum output power and maximum speed of the drive motor 23. For example, limp mode includes a maximum output power limit: limiting the maximum output power of the drive motor to 30%~50% of its rated power to ensure the motor operates at low power, avoiding excessive power demand that could cause the remaining battery branches to discharge too quickly. Limp mode also includes a maximum speed limit: limiting the loader's maximum speed to 5km / h~10km / h to ensure the vehicle can travel at low speeds, avoiding excessive speed that could cause the remaining normal battery branches to discharge too quickly, facilitating the driver's safe transfer of the vehicle to the repair site. In some embodiments, in limp mode, the VCU also issues a fault warning to the driver via the display screen 54, informing them that the vehicle is currently in limp mode and suggesting that they leave the work area for repairs as soon as possible. This embodiment enables limp mode when power is severely insufficient, ensuring that the loader can drive away from the work area on its own, avoiding work interruption and traffic congestion caused by machine downtime. It also prevents excessive discharge by limiting power and vehicle speed, thus ensuring the loader's relocation, such as to a maintenance site. At the same time, it protects the remaining battery branches and prevents secondary failures caused by over-discharge.

[0033] In some embodiments, the loader's drive control method further includes working condition identification. Working condition identification involves the vehicle controller 53 identifying the loader's current operating condition based on signals from the accelerator pedal 52, the operating handle 51, the load cell 48 of the bucket 45, the first displacement sensor 47 of the lifting cylinder 43, and the second displacement sensor 49 of the bucket cylinder 46. The current operating condition includes full-load operation, no-load operation, material pushing operation, and driving / transfer operation. The accelerator pedal 52 signal is used to determine if the driver has a driving command. The operating handle 51 signal is used to determine if the driver has hydraulic operation commands, including lifting, lowering, bucket retraction, and tilting operation signals. The load cell 48 is used to detect the load status of the bucket. When the load cell signal value is greater than a preset no-load threshold, it is determined to be in a full-load state; when the load cell signal value is less than the preset no-load threshold, it is determined to be in a no-load state. The first displacement sensor 47 of the lifting cylinder 43 is used to determine the extension / retraction state of the lifting cylinder, that is, to determine the extension length of the piston rod of the lifting cylinder relative to the cylinder barrel, thereby detecting the lifting height of the boom 45 and determining the boom's posture. The second displacement sensor 49 of the bucket cylinder 46 is used to determine the extension / retraction state of the bucket cylinder, that is, to determine the extension length of the piston rod of the bucket cylinder relative to the cylinder barrel, thereby detecting the rotation angle of the bucket relative to the boom and determining the bucket's posture.

[0034] Based on the combination of the above signals, the VCU identifies the loader's current operating condition as either fully loaded, unloaded, pushing, or traveling / transferring. For example, if the accelerator pedal and control handle both issue commands, and the bucket's load cell detects a full load, the current operating condition is determined to be fully loaded. If the accelerator pedal and control handle both issue commands, and the bucket's load cell detects an unloaded state, the current operating condition is determined to be unloaded. If the accelerator pedal issues commands, but the control handle does not issue lifting or bucket retraction commands, and the second displacement sensor 49 of the bucket cylinder detects that the piston rod's extension length relative to the cylinder barrel is less than a first preset threshold, the current operating condition is determined to be pushing. If neither the accelerator pedal nor the control handle issues commands, and the first displacement sensor detects that the piston rod's extension length relative to the cylinder barrel of the lifting cylinder is less than the second preset threshold, and the second displacement sensor 49 detects that the piston rod's extension length relative to the cylinder barrel of the bucket cylinder is less than the first preset threshold, it indicates that both the boom and bucket are in their lowest positions, and the loader is being used for traveling / transferring.

[0035] In some embodiments, the drive control method for the loader further includes: power distribution of the travel motors, including the vehicle controller 53 distributing the output power of the travel motors 23 at the wheel ends of the front and rear frames according to the identified current operating conditions and the obtained vertical load distribution ratio of the front and rear frames. The vertical load distribution ratio of the front and rear frames refers to the proportion of the total vehicle weight borne by the front and rear frames of the loader, respectively. Since the front axle and rear axle are mounted on the front and rear frames respectively, the vertical load distribution ratio of the front and rear frames is also the proportion of the total vehicle weight borne by the front and rear axles of the loader. This ratio varies with the bucket load state and the boom posture. For example, when the bucket is fully loaded and the boom is raised to a high position, the front frame load ratio is higher; when the bucket is unloaded and the boom is in a low position, the rear frame load ratio is higher. The VCU calculates the power distribution coefficient of the travel motors at the front and rear wheels according to the current operating conditions and the vertical load distribution ratio. For example, if the front frame load accounts for 60% and the rear frame load accounts for 40%, the VCU sets the output power of the front wheel-side drive motor to 60% of the total drive power and the rear wheel-side drive motor to 40%. After allocation, the VCU controls the electric drive system 30, which controls the drive motors 23 on the front and rear frames to output power according to the allocated power through the drive motor drivers. Then, each drive motor transmits power to the drive wheels 32 through the wheel-side reducers 31. In this embodiment, the drive motors 23 on the front and rear frames are allocated according to the actual load ratio of the front and rear frames, so that each drive wheel can make full use of the ground adhesion, avoid tire slippage caused by improper power allocation, and improve energy utilization efficiency. Compared with the average power allocation scheme in the prior art, this embodiment can significantly reduce tire wear and improve the overall vehicle economy.

[0036] In some embodiments, obtaining the vertical load distribution ratio of the front and rear frames of the loader includes: obtaining the posture of the boom 45 based on the signal from the first displacement sensor of the lifting cylinder; and the vehicle controller 53 obtaining the vertical load distribution ratio of the front and rear frames of the loader based on the current working conditions and the posture of the boom 45. Specifically, the VCU pre-stores a load distribution mapping table, which is obtained through experimental calibration and records the vertical load distribution ratio of the front and rear frames under different working conditions and boom postures. For example, under fully loaded working conditions, when the boom posture is in a low position (the first displacement sensor detects that the extension displacement of the piston rod of the lifting cylinder is 0~50mm), the front frame load accounts for 40%, and the rear frame load accounts for 60%. Under fully loaded working conditions, when the boom posture is in a medium-low position (the first displacement sensor detects that the extension displacement of the piston rod of the lifting cylinder is 51~150mm), the front frame load accounts for 45%, and the rear frame load accounts for 55%. When the boom is in a low position (the first displacement sensor detects that the extension displacement of the piston rod of the lifting cylinder is 0~50mm) under no-load operation conditions, the load on the front frame accounts for 35% and the load on the rear frame accounts for 65%.

[0037] In some embodiments, a loader is also disclosed, the loader including a multi-branch battery system, an electrical load, a power distribution unit, and a vehicle controller 53.

[0038] like Figure 1 As shown, the multi-branch battery system includes multiple battery branches connected in parallel, and each battery branch includes a battery pack 11 and a DC-DC converter 12.

[0039] The electrical load includes multiple first load branches and at least one second load branch. The first load branches include a drive motor driver 21 and a drive motor 23, and the second load branch includes a hydraulic motor driver 22 and a hydraulic motor 24. Figure 1 In the illustrated embodiment, the electrical load also includes a high-voltage fan 25. A power distribution unit 2 is connected between the multi-branch battery system and the electrical load. In the illustrated embodiment, the power distribution unit 2 includes a high-voltage distribution unit (PDU). A vehicle controller 53 is electrically connected to a DC-DC converter 12, a drive motor driver 21, and a hydraulic motor driver 22, respectively. The vehicle controller 53 is configured to perform any of the aforementioned drive control methods. In the illustrated embodiment, the loader also includes a low-voltage battery 13 directly connected to the DC-DC converter 12, and a low-voltage accessory 14 and an electric water pump 15 connected to the low-voltage battery 13.

[0040] In some embodiments, the loader further includes a load cell 48 and a first displacement sensor 47. The load cell 48 is mounted on the bucket 46 and is used to detect the load status of the bucket 46; the first displacement sensor 47 is mounted on the lifting cylinder and is used to detect the posture of the boom 45; the vehicle controller 53 identifies the loader's operating conditions based on the signals from the load cell 48 and the first displacement sensor. During operation, the vehicle controller 53 controls the electric drive system to drive the hydraulic motor 24, which in turn drives the hydraulic oil pump 41. The hydraulic oil pump 41 outputs hydraulic oil, which is then delivered through the hydraulic valve group 42 to the lifting cylinder 43 and the bucket cylinder 44 to control the movements of the boom and bucket, respectively.

[0041] In some embodiments, the vehicle controller 53 is configured to: regulate the voltage of each battery branch during normal operation via the DC-DC converter 12; the DC-DC converter 12 stabilizes the output voltage of the corresponding battery branch within a preset voltage range (e.g., 600V~800V), ensuring the voltage stability of the high-voltage bus and avoiding circulating current problems caused by voltage differences between branches. The vehicle controller 53 also performs active equalization charging and discharging for battery branches whose voltage deviates from the preset range. The VCU monitors the voltage of each battery branch in real time. When the voltage difference between a branch and the average voltage of other branches exceeds a preset threshold (e.g., ±50mV), the VCU sends an equalization command to the DC-DC converter 12 of that branch via the CAN bus. The DC-DC converter 12, according to the command, discharges from the branch with higher voltage to the branch with lower voltage, or replenishes power from the high-voltage bus to the branch with lower voltage, achieving active equalization. When the voltage difference between all branches is less than the preset threshold, the VCU resumes the multi-branch parallel power supply mode.

[0042] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them; although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific implementation of the present invention or equivalent substitutions can be made to some technical features without departing from the spirit of the technical solutions of the present invention, and all such modifications and substitutions should be covered within the scope of the technical solutions claimed in the present invention.

Claims

1. A drive control method for a loader, characterized in that, The loader includes a multi-branch battery system, a travel motor for driving the travel device, and a hydraulic motor for driving the hydraulic working device. The multi-branch battery system consists of multiple battery branches connected in parallel. The control method includes: The vehicle controller monitors the operating status of each battery branch in real time; When a power-down fault is detected in at least one battery branch, the vehicle controller obtains the total output power of the remaining normal battery branches and compares the total output power of the remaining normal battery branches with the power threshold of the current operating condition in a graded manner. The power threshold includes a first power threshold and a second power threshold, and the first power threshold > the second power threshold. The vehicle controller executes a hierarchical control strategy based on the comparison results: If the total output power of the remaining normal battery branches is greater than or equal to the first power threshold, then the driving motor and the hydraulic motor that control the current working condition will both operate at normal power. If the second power threshold ≤ the total output power of the remaining normal battery branch < the first power threshold, then control the driving motor of the current working condition to run at normal power, and at the same time control the hydraulic motor of the current working condition to run in power-limited working mode. If the total output power of the remaining normal battery branches is less than the second power threshold, then the hydraulic motor will stop running and the driving motor will run.

2. The drive control method according to claim 1, characterized in that, The first power threshold is the maximum power requirement under normal operating conditions of the current working condition; the second power threshold is the minimum power requirement under acceptable operating efficiency of the current working condition.

3. The drive control method according to claim 1, characterized in that, The vehicle controller detects the operating status of each battery branch by detecting the voltage, current, temperature and / or resistance of each battery branch. When any of the detected parameters exceeds the preset safety range, it is determined that the battery branch has a power-off fault.

4. The drive control method according to claim 1, characterized in that, In the hierarchical control strategy, when the total output power of the remaining normal battery branches is less than the second power threshold, the drive motor is controlled to operate in limp mode, which limits the maximum output power and maximum vehicle speed of the drive motor.

5. The drive control method according to claim 1, characterized in that, Also includes: Operating condition identification includes the vehicle controller identifying the current operating condition of the loader based on signals from the accelerator pedal, the operating handle, the load cell of the bucket, the first displacement sensor of the lifting cylinder, and the second displacement sensor of the bucket cylinder. The current operating condition includes fully loaded operating condition, unloaded operating condition, material pushing operating condition, and driving and relocation operating condition.

6. The drive control method according to claim 5, characterized in that, Also includes: The power distribution of the travel motors includes the vehicle controller allocating the output power of the travel motors at the wheel ends of the front and rear frames based on the identified current operating conditions and the obtained vertical load distribution ratio of the front and rear frames.

7. The drive control method according to claim 6, characterized in that, The process of obtaining the vertical load distribution ratio of the front and rear frames of the loader includes: obtaining the boom posture based on the signal from the first displacement sensor of the lifting cylinder, and the vehicle controller obtaining the vertical load distribution ratio of the front and rear frames of the loader based on the current working conditions and the boom posture.

8. A loader, characterized in that, include: A multi-branch battery system, comprising multiple battery branches connected in parallel, each battery branch including a battery pack and a DC-DC converter; An electrical load includes multiple first load branches and at least one second load branch, wherein the first load branches include a drive motor driver and a drive motor, and the second load branch includes a hydraulic motor driver and a hydraulic motor; A power distribution unit is connected between the multi-branch battery system and the electrical load; The vehicle controller is electrically connected to the DC-DC converter, the drive motor driver, and the hydraulic motor driver, respectively, and the vehicle controller is configured to perform the drive control method according to any one of claims 1 to 7.

9. The loader according to claim 8, characterized in that, Also includes: A load cell, installed in the bucket, is used to detect the load status of the bucket; The first displacement sensor, mounted on the lifting cylinder, is used to detect the attitude of the boom; The vehicle controller identifies the loader's operating conditions based on signals from the weighing sensor and the first displacement sensor.

10. The loader according to claim 8, characterized in that, The vehicle controller is configured to: perform voltage regulation control on each battery branch during normal operation via the DC-DC converter; and perform active equalization charging and discharging on battery branches whose voltage deviates from a preset range.

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