Drive-by-wire lifting control system and method for unmanned off-highway wide-body dumper

Abstract

The invention discloses a drive-by-wire lifting control system and method for an unmanned off-highway wide-body dumper, the system comprises an inflation pump, a dryer and an air cylinder, the air cylinder is connected with a power takeoff electromagnetic valve, a descending electromagnetic valve and a lifting electromagnetic valve, and one end of each electromagnetic valve is connected with a whole dumper controller; the power takeoff electromagnetic valve is connected with a gearbox and power takeoff assembly and is sequentially connected with a power takeoff shaft and a gear pump, the lifting electromagnetic valve is connected with a limiting valve, the gear pump, the descending electromagnetic valve and the limiting valve are respectively connected with a lifting control valve, the gear pump and the lifting control valve are connected with an oil tank, and the lifting control valve is connected with a first lifting hydraulic oil cylinder and a second lifting hydraulic oil cylinder. According to the drive-by-wire lifting control system and method for the unmanned off-highway wide-body dumper, the power takeoff / lifting / descending electromagnetic valve is used for controlling the on-off of each gas circuit so as to control a hydraulic oil loop, the lifting and descending functions of a container are achieved in a pneumatic control and hydraulic control mode, the operation efficiency and the equipment reliability are improved, and the labor intensity of workers is reduced. And the operation cost and the safety risk are effectively reduced.

Description

Technical Field

[0001] This invention relates to the field of unmanned off-highway wide-body dump truck technology, and more specifically, to a wire-controlled lifting control system and method for unmanned off-highway wide-body dump trucks. Background Technology

[0002] In the transportation of vehicles such as mining trucks and dump trucks, hydraulic lifting systems are typically installed to facilitate unloading by tipping the cargo box. With the development of intelligent vehicles, higher demands are being placed on the automation and precise control of lifting systems, requiring more advanced control methods to improve operational convenience and safety.

[0003] Currently, the lifting systems commonly used in wide-body mining cars generally consist of a lever mechanism, oil tank, oil pump, pneumatic directional valve, and hydraulic cylinder connected by oil pipes. The lifting handle is located in the cab and uses a mechanical three-position five-way valve. The driver controls the air intake and exhaust of the pneumatic directional valve through the lifting handle to achieve three adjustment positions: up, down, and stop, thereby controlling the lifting and lowering of the cargo box. The aforementioned valve body typically only has an opening or closing function and cannot achieve linear proportional control of the cargo box lifting or lowering process. This results in uneven operation, significant impact on the chassis, and a shortened service life of the chassis.

[0004] Therefore, there is an urgent need for a wire-controlled lifting control system and method for unmanned off-highway wide-body dump trucks. Summary of the Invention

[0005] The purpose of this invention is to provide a wire-controlled lifting control system and method for unmanned off-highway wide-body dump trucks to solve the problems in the prior art. It can use pneumatic and hydraulic control to realize functions such as lifting and lowering of the cargo box, improve operating efficiency and equipment reliability, and effectively reduce operating costs and safety risks.

[0006] This invention provides a drive-by-wire lifting control system for an unmanned off-highway wide-body dump truck, comprising: an air pump, a dryer, and an air tank arranged in sequence; the air tank is connected in parallel to a power take-off (PTO) solenoid valve, a lowering solenoid valve, and a lifting solenoid valve; one end of each of the PTO, lowering, and lifting solenoid valves is connected to a high-drive signal from a vehicle controller, and the other end is grounded; the PTO solenoid valve is connected to a gearbox with a PTO assembly; the gearbox with the PTO assembly is sequentially connected to a power take-off shaft and a gear pump; the lifting solenoid valve is connected to a limit valve; the gear pump, the lowering solenoid valve, and the limit valve are each connected to a lifting control valve; the gear pump and the lifting control valve are connected to an oil tank; and the lifting control valve is also connected in parallel to a first lifting hydraulic cylinder and a second lifting hydraulic cylinder.

[0007] In the above-described unmanned off-highway wide-body dump truck wire-controlled lifting control system, preferably, the air tank is connected to a gas main pipe, and the gas main pipe is respectively provided with a first air pipe, a second air pipe and a third air pipe, the power take-off solenoid valve is provided on the first air pipe, the lowering solenoid valve is provided on the second air pipe, and the lifting solenoid valve is provided on the third air pipe.

[0008] In the above-described unmanned off-highway wide-body dump truck drive-by-wire lifting control system, preferably, the power take-off solenoid valve is connected to the gearbox with power take-off assembly via a fourth air pipe; the lowering solenoid valve and the lifting solenoid valve are connected to the lifting control valve via a fifth air pipe; the lifting solenoid valve is connected to the limit valve via a sixth air pipe; and the limit valve is connected to the lifting control valve via a seventh air pipe.

[0009] In the unmanned off-highway wide-body dump truck drive-by-wire lifting control system described above, preferably, the first lifting hydraulic cylinder and the second lifting hydraulic cylinder are symmetrically mounted on the left and right longitudinal beams of the vehicle frame; the gear pump is fixed on the gear pump mounting bracket.

[0010] In the unmanned off-highway wide-body dump truck drive-by-wire lifting control system described above, preferably, the gear pump is connected to the oil tank via a first oil pipe; the gear pump is connected to the lifting control valve via a second oil pipe; the lifting control valve is connected to the first lifting hydraulic cylinder and the second lifting hydraulic cylinder via a three-way valve; the lifting control valve is connected to the three-way valve via a third oil pipe; and the lifting control valve is connected to the oil tank via a fourth oil pipe.

[0011] The unmanned off-highway wide-body dump truck drive-by-wire lifting control system described above preferably includes an intelligent driving controller and a cargo box angle sensor, wherein the vehicle controller, the intelligent driving controller, and the cargo box angle sensor communicate with each other via a CAN network.

[0012] In the unmanned off-highway wide-body dump truck drive-by-wire lifting control system described above, preferably, the gear pump is connected to a power take-off air source, the limit valve is connected to a lifting air source, and the lifting control valve is connected to a lowering air source.

[0013] The present invention also provides a drive-by-wire lifting control method for an unmanned off-highway wide-body dump truck using the above-described system, comprising the following steps:

[0014] When the power take-off (PTO) is engaged, the lifting oil pump operates: When lifting the cargo box, the PTO solenoid valve is energized, connecting the PTO control air circuit. The gearbox engages with the PTO assembly, transmitting the motor power to the PTO and gear pump through the gearbox, causing the gear pump to rotate at high speed. The gear pump pumps hydraulic oil from the oil tank, and the high-pressure oil flows back to the oil tank through the oil passage inside the lifting solenoid valve, thus circulating in this way.

[0015] Lifting state: When lifting the cargo box, the lifting solenoid valve is energized and the system air pressure flows through the lifting solenoid valve and the limit valve into the lifting control valve through the lifting interface. It acts on the cylinder piston of the lifting control valve, pushing the piston to the left and driving the valve core to the left, connecting the oil pump interface with the lifting cylinder interface. High-pressure oil enters the cylinder and lifts the cylinder.

[0016] Descent state: When the cargo box is lowered, after the descent solenoid valve is energized, the system air pressure enters the lifting control valve through the descent interface via the descent solenoid valve. This pressure acts on the piston of the lifting control valve, pushing the piston to the right and causing the valve core to move to the right, connecting the lifting cylinder interface with the return oil interface. The high-pressure oil in the cylinder then flows back to the oil tank.

[0017] The above-described unmanned off-highway wide-body dump truck drive-by-wire lifting control method preferably includes the following steps: The power take-off (PTO) is engaged before the PTO solenoid valve is energized, and the lifting oil pump operates as follows:

[0018] The intelligent driving controller sends a lifting request CAN signal to the vehicle controller. First, it connects the transmission with the power take-off assembly to the lifting oil pump. The vehicle controller then determines the vehicle's status. Once the conditions are met, it outputs a high-drive signal to the power take-off solenoid valve to energize it.

[0019] Before the lifting solenoid valve is energized, the lifting state includes:

[0020] The intelligent driving controller sends a lifting command CAN signal to the vehicle controller, which then outputs a high-drive signal to the lifting solenoid valve to energize it.

[0021] The lifting state also includes:

[0022] If the lifting pressure exceeds the preset pressure threshold, the bypass relief valve will open.

[0023] The initial rated speed of the power take-off (PTO) issued by the vehicle controller is 1200 r / min. During the lifting process, the cargo box angle sensor measures the lifting angle in real time and sends it to the vehicle controller and intelligent driving controller via the CAN network. This allows the intelligent driving controller to calculate the lifting speed based on the rate of change of the lifting angle. If it is necessary to increase the lifting speed, the intelligent driving controller sends an accelerator pedal opening signal to the vehicle controller, which then controls the PTO speed to increase.

[0024] Within 5 degrees before the vehicle is fully lifted, the intelligent driving controller linearly reduces the throttle opening signal value.

[0025] Before the descent solenoid valve is energized, the descent state includes:

[0026] The intelligent driving controller sends a descent command CAN signal to the vehicle controller, and the vehicle controller outputs a high-drive signal to the descent solenoid valve to energize it.

[0027] The above-described unmanned off-highway wide-body dump truck drive-by-wire lifting control method preferably further includes:

[0028] Intermittent Stop State: During the lifting or lowering process, the lifting or lowering command is stopped, so that the compressed air acting on the piston in the lifting control valve is discharged from the exhaust port of the lifting solenoid valve or the lowering solenoid valve. Then, the valve core returns to the middle position under the action of the spring force, cutting off the connection between the cylinder interface and other interfaces. The high-pressure oil in the cylinder stops flowing in or out, and the cylinder piston is in a stationary state.

[0029] The unmanned off-highway wide-body dump truck drive-by-wire lifting control method also includes:

[0030] Limit state: When the first or second lifting hydraulic cylinder rises to the set lifting height, it will touch the limit valve, causing the valve core of the limit valve to move, cutting off the air passage between the system air pressure and the lifting control valve, and causing the compressed air acting on the piston of the lifting control valve to be discharged from the exhaust port of the limit valve. In this way, the valve core of the lifting control valve will return to the middle position under the action of the spring force, cutting off the connection between the lifting cylinder interface and the oil pump interface, and the first or second lifting hydraulic cylinder will stop rising.

[0031] This invention provides a drive-by-wire lifting control system and method for unmanned off-highway wide-body dump trucks. It controls the on / off of various air circuits via power take-off solenoid valves, lifting solenoid valves, and lowering solenoid valves, thereby controlling the hydraulic oil circuit. Employing a pneumatic-hydraulic control method, it achieves functions such as cargo box lifting and lowering, improving operational efficiency and equipment reliability, effectively reducing operating costs and safety risks. It solves the problems of existing lifting systems' inability to achieve linear proportional control of the cargo box lifting or lowering process, resulting in uneven movements and significant impact on the vehicle frame. Simultaneously, it achieves more precise lifting control, improving system safety and reliability. Through signal interaction between the intelligent driving controller and the VCU, it realizes… Through precise control of the air and oil circuits via electrical signals, and speed adjustment and limit functions achieved through sensor feedback, unmanned intelligent control is realized, along with dynamic adjustment of the lifting process, rather than simple opening and closing control. This enables precise control of the cargo box's lifting and lowering process, allowing adjustment of the lifting speed as needed, effectively avoiding impact on the chassis and extending its service life. Simultaneously, the power take-off speed can be adjusted based on cargo box angle feedback, thereby adjusting the lifting speed in real time. Furthermore, it features comprehensive mid-stop and limit functions, making control more flexible, operation safer, and more adaptable. The mid-stop and limit functions enhance operational safety and convenience. Attached Figure Description

[0032] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described below with reference to the accompanying drawings, wherein:

[0033] Figure 1 A schematic diagram of the circuit connection structure of an embodiment of the wire-controlled lifting control system for unmanned off-highway wide-body dump trucks provided by the present invention;

[0034] Figure 2 A schematic diagram of the network topology of an embodiment of the unmanned off-highway wide-body dump truck wire-controlled lifting control system provided by the present invention;

[0035] Figure 3 A schematic diagram of the mechanical structure of an embodiment of the unmanned off-highway wide-body dump truck wire-controlled lifting control system provided by the present invention;

[0036] Figure 4 A schematic diagram illustrating the working principle of the lifting system in an embodiment of the wire-controlled lifting control system for unmanned off-highway wide-body dump trucks provided by the present invention.

[0037] Figure 5 A flowchart illustrating an embodiment of the drive-by-wire lifting control method for unmanned off-highway wide-body dump trucks provided by the present invention;

[0038] Figure 6 This is a logic diagram of an embodiment of the drive-by-wire lifting control method for unmanned off-highway wide-body dump trucks provided by the present invention.

[0039] Explanation of reference numerals in the attached diagram: 1-Air pump, 2-Dryer, 3-Air tank, 4-Vehicle controller, 5-Power take-off solenoid valve, 6-Lowering solenoid valve, 7-Lifting solenoid valve, 8-Limit valve, 9-Gearbox with power take-off assembly, 10-Power take-off shaft, 11-Gear pump mounting bracket, 12-Gear pump, 13-Lifting control valve, 14-Oil tank, 15-First lifting hydraulic cylinder, 16-Second lifting hydraulic cylinder, 17-Third lifting hydraulic cylinder 18-Power Take-Off Air Source, 19-Lifting Air Source, 20-Lowering Air Source, 21-Intelligent Driving Controller, 22-Cargo Box Angle Sensor, 23-Main Gas Pipe, 24-First Air Pipe, 25-Second Air Pipe, 26-Third Air Pipe, 27-Fourth Air Pipe, 28-Fifth Air Pipe, 29-Sixth Air Pipe, 30-Seventh Air Pipe, 31-First Oil Pipe, 32-Second Oil Pipe, 33-Third Oil Pipe, 34-Fourth Oil Pipe. Detailed Implementation

[0040] Various exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. The descriptions of the exemplary embodiments are merely illustrative and are in no way intended to limit the present disclosure or its application or use. The present disclosure may be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided so that the present disclosure will be thorough and complete, and will fully express the scope of the disclosure to those skilled in the art. It should be noted that, unless specifically stated otherwise, the relative arrangement of components and steps, the composition of materials, numerical expressions, and values ​​set forth in these embodiments should be interpreted as exemplary only and not as limiting.

[0041] The terms “first,” “second,” and similar terms used in this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different parts. Terms such as “including” or “contains” mean that the element preceding the term encompasses the element listed after it, and do not exclude the possibility of encompassing other elements as well. Terms such as “above” and “below” are used only to indicate relative positional relationships; when the absolute position of the described object changes, this relative positional relationship may also change accordingly.

[0042] In this disclosure, when a specific component is described as being located between a first component and a second component, an intermediary component may or may not be present between the specific component and the first or second component. When a specific component is described as connecting to other components, the specific component may be directly connected to the other components without having an intermediary component, or it may not be directly connected to the other components but may have an intermediary component.

[0043] All terms used in this disclosure (including technical or scientific terms) have the same meaning as understood by one of ordinary skill in the art to which this disclosure pertains, unless otherwise specifically defined. It should also be understood that terms defined in a general dictionary, such as a dictionary, should be interpreted as having a meaning consistent with their meaning in the context of the relevant art, and not as having an idealized or highly formalized meaning, unless expressly defined herein.

[0044] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, they should be considered part of the specification.

[0045] like Figures 1-4 As shown, the unmanned off-highway wide-body dump truck drive-by-wire lifting control system provided in this embodiment includes: an air pump 1, a dryer 2, and an air tank 3 arranged in sequence. The air tank 3 is connected in parallel to a power take-off solenoid valve 5, a lowering solenoid valve 6, and a lifting solenoid valve 7. One end of each of the power take-off solenoid valve 5, the lowering solenoid valve 6, and the lifting solenoid valve 7 is connected to a high-drive signal of a vehicle control unit (VCU) 4, and the other end is grounded. The power take-off solenoid valve 5 is connected to a gearbox with a power take-off assembly 9. The gearbox with a power take-off assembly 9 is connected in sequence to a power take-off shaft 10 and a gear pump 12. The lifting solenoid valve 7 is connected to a limit valve 8. The gear pump 12, the lowering solenoid valve 6, and the limit valve 8 are respectively connected to a lifting control valve 13. The gear pump 12 and the lifting control valve 13 are connected to an oil tank 14. The lifting control valve 13 is also connected in parallel to a first lifting hydraulic cylinder 15 and a second lifting hydraulic cylinder 16.

[0046] The gear pump 12 is connected to a power take-off air source 18, the limit valve 8 is connected to a lifting air source 19, and the lifting control valve 13 is connected to a lowering air source 20. Figure 1 In the diagram, the thin solid line represents the air passage, and the thick solid line represents the oil passage; Figure 4 In the diagram, the dashed line represents the air passage, and the solid line represents the oil passage.

[0047] Furthermore, the unmanned off-highway wide-body dump truck drive-by-wire lifting control system also includes a driver controller (MDC) 21 and a cargo box angle sensor 22. The vehicle controller 4, the driver controller 21, and the cargo box angle sensor 22 communicate with each other via a CAN network. The lifting system involved in this invention is a parking power take-off (PTO). Through the interaction between the driver controller 21 and the vehicle controller (VCU) 4, the PTO solenoid valve 5, the lifting solenoid valve 7, and the lowering solenoid valve 6 are controlled. The solenoid valves control the opening and closing of the air circuit, thereby controlling the hydraulic oil circuit. The cargo box lifting and lowering functions are realized by adopting a pneumatic-hydraulic control method.

[0048] Specifically, the power take-off solenoid valve 5, the lifting solenoid valve 7, and the lowering solenoid valve 6 have the same functional principle. They are all valve bodies with an electro-pneumatic structure. One end of the coil of the solenoid valve is grounded, and the other end is connected to the vehicle controller (VCU) 4. When the vehicle controller 4 receives the power take-off opening command issued by the intelligent driving controller 21, the vehicle controller 4 outputs a high-drive signal to the solenoid valve through a pin. After the solenoid valve is energized, the air circuit opens, and the air source drives the power take-off to engage. The working principle of the lifting solenoid valve 7 and the lowering solenoid valve 6 is the same.

[0049] Furthermore, the air storage cylinder 3 is connected to a gas main pipe 23, and a first air pipe 24, a second air pipe 25 and a third air pipe 26 are respectively provided on the gas main pipe 23. The power take-off solenoid valve 5 is provided on the first air pipe 24, the lowering solenoid valve 6 is provided on the second air pipe 25, and the lifting solenoid valve 7 is provided on the third air pipe 26.

[0050] Furthermore, the power take-off solenoid valve 5 is connected to the gearbox with power take-off assembly 9 via the fourth air pipe 27; the lowering solenoid valve 6 and the lifting solenoid valve 7 are connected to the lifting control valve 13 via the fifth air pipe 28; the lifting solenoid valve 7 is connected to the limit valve 8 via the sixth air pipe 29; and the limit valve 8 is connected to the lifting control valve 13 via the seventh air pipe 30.

[0051] Furthermore, the first lifting hydraulic cylinder 15 and the second lifting hydraulic cylinder 16 are symmetrically mounted on the left and right longitudinal beams of the vehicle frame, making lifting more stable and preventing cargo box tilting during lifting. Figure 1 As shown, the first lifting hydraulic cylinder 15 and the second lifting hydraulic cylinder 16 have only one oil port. During lifting, high-pressure oil enters through this port to lift the cylinder; during lowering, the cylinder returns to its original position under the weight of the cargo box, and the hydraulic oil returns to the oil tank 14 from this port. The gear pump 12 is fixed on the gear pump mounting bracket 11.

[0052] Furthermore, the gear pump 12 is connected to the oil tank 14 via the first oil pipe 31; the gear pump 12 is connected to the lifting control valve 13 via the second oil pipe 32; the lifting control valve 13 is connected to the first lifting hydraulic cylinder 15 and the second lifting hydraulic cylinder 16 via the three-way valve 17; the lifting control valve 13 is connected to the three-way valve 17 via the third oil pipe 33; and the lifting control valve 13 is connected to the oil tank 14 via the fourth oil pipe 34.

[0053] like Figure 1 As shown, the lifting control valve 13 is a three-position three-way control valve with three oil ports: a gear oil pump port, an oil tank return port, and a lifting cylinder port. It also has two air ports: a descent port and a lifting port. Additionally, it includes a pressure gauge port and an overflow valve.

[0054] like Figure 5 and Figure 6 As shown, the drive-by-wire lifting control method for unmanned off-highway wide-body dump trucks provided in this embodiment includes the following steps in actual execution:

[0055] Step S1: Power Take-Off (PTO) connection, lifting oil pump operation: When lifting the cargo box, the PTO solenoid valve 5 is energized, connecting the PTO control air circuit. The gearbox and PTO assembly 9 are engaged, transmitting the motor power to the PTO and gear pump 12 through the gearbox, causing the gear pump 12 to rotate at high speed. The gear pump 12 pumps hydraulic oil out of the oil tank 14, and the high-pressure oil flows back to the oil tank through the oil passage inside the lifting solenoid valve 7, thus circulating.

[0056] Furthermore, before the power take-off solenoid valve 5 is energized, the power take-off is engaged, and the lifting oil pump operates as follows:

[0057] The intelligent driving controller 21 sends a lifting request CAN signal to the vehicle controller 4. First, it connects the transmission with the power take-off assembly 9 to the lifting oil pump. The vehicle controller 4 judges the vehicle status and, when the conditions are met, outputs a high-drive signal to the power take-off solenoid valve 5 to energize the power take-off solenoid valve 5.

[0058] Specifically, such as Figure 6 As shown, in the specific implementation, after initialization, the vehicle controller 4 and the intelligent driving controller 21 shake hands. Then, the intelligent driving controller 21 sends a lift request CAN signal to the vehicle controller 4. The vehicle controller 4 determines whether it meets the requirements to enter the power take-off mode. If so, the vehicle controller 4 sends a power take-off solenoid valve working command. The vehicle controller 4 sends a high-side drive hard wire signal to the power take-off solenoid valve 5 to control the power take-off solenoid valve 5 to work. The power take-off air source 18 drives the gearbox to engage with the power take-off assembly 9.

[0059] Step S2, Lifting State: When lifting the cargo box, the lifting solenoid valve 7 is energized and the system air pressure flows through the lifting solenoid valve 7 and the limit valve 8 into the lifting control valve 13 through the lifting interface. This pressure acts on the cylinder piston of the lifting control valve 13, pushing the piston to the left and causing the valve core to move to the left, connecting the oil pump interface with the lifting cylinder interface. High-pressure oil then enters the cylinder and lifts it up.

[0060] Before the lifting solenoid valve 7 is energized, the lifting state includes:

[0061] The intelligent driving controller 21 sends a lifting command CAN signal to the vehicle controller 4, and the vehicle controller 4 outputs a high-drive signal to the lifting solenoid valve 7 to energize and operate the lifting solenoid valve 7.

[0062] Furthermore, the lifting state also includes:

[0063] If the lifting pressure exceeds the preset pressure threshold, the bypass relief valve will open to prevent the pressure from continuing to rise and causing damage to the gear pump and pipeline.

[0064] The initial rated speed of the power take-off (PTO) issued by the vehicle controller 4 is 1200 r / min. During the lifting process, the cargo box angle sensor 22 measures the lifting angle in real time and sends it to the vehicle controller 4 and the intelligent driving controller 21 via the CAN network. This allows the intelligent driving controller 21 to calculate the lifting speed based on the rate of change of the lifting angle. If it is necessary to increase the lifting speed, the intelligent driving controller 21 sends an accelerator pedal opening signal to the vehicle controller 4. The vehicle controller 4 then controls the PTO speed to increase, thereby achieving the purpose of increasing the lifting speed.

[0065] Within 5° before the vehicle is fully lifted, the intelligent driving controller 21 linearly reduces the throttle opening signal value to reduce the speed of the power take-off and prevent the high speed from impacting the system after the vehicle is fully lifted.

[0066] Step S3, Lowering State: When the cargo box is lowered, after the lowering solenoid valve 6 is energized, the system air pressure enters the lifting control valve 13 through the lowering interface via the lowering solenoid valve 6, acts on the piston of the lifting control valve 13, pushes the piston to move to the right, and drives the valve core to move to the right, connecting the lifting cylinder interface with the return oil interface, so that the high-pressure oil in the cylinder flows back to the oil tank.

[0067] It is evident that the descent process can be completed solely by the gravity of the cargo box. Specifically, before the descent solenoid valve 6 is energized, the descent state includes:

[0068] The intelligent driving controller 21 sends a descent command CAN signal to the vehicle controller 4, and the vehicle controller 4 outputs a high-drive signal to the descent solenoid valve 6 to energize and operate the descent solenoid valve 6.

[0069] Specifically, after the vehicle controller 4 issues the power take-off solenoid valve working command, it performs a power take-off (PTO) engagement status judgment. If the PTO engagement is successful, it determines whether the lifting or lowering conditions are met.

[0070] If the lifting conditions are met, the vehicle enters lifting mode. The vehicle controller 4 sends a lifting solenoid valve operating command and a speed command to the motor control unit (MCU). Specifically, the vehicle controller 4 sends a speed mode and PTO speed (e.g., 800 rpm) command to the MCU to control the PTO to operate at the corresponding speed. The PTO speed can respond to the throttle opening. Then, after receiving the lifting request command from the intelligent driving controller, the vehicle controller 4 sends a high-side drive hardwire signal to the lifting solenoid valve 7 to control its operation. Lifting conditions are considered met if the following conditions are simultaneously met: the vehicle is in neutral (N), the vehicle's handbrake or EPB is engaged, and the intelligent driving controller sends a lifting request CAN signal to the vehicle controller.

[0071] If the descent conditions are met, the vehicle enters descent mode. The vehicle controller 4 issues a descent solenoid valve operation command. Specifically, after receiving the descent request command from the intelligent driving controller 21, the vehicle controller 4 sends a high-side drive hardwire signal to the descent solenoid valve 6 to control its operation. The descent conditions are considered met if the following conditions are simultaneously met: the vehicle is in neutral (N), the vehicle's handbrake or EPB is engaged, and the intelligent driving controller sends a descent request CAN signal to the vehicle controller.

[0072] Furthermore, in one embodiment of the present invention, the unmanned off-highway wide-body dump truck drive-by-wire lifting control method further includes:

[0073] Intermittent Stop State: During the lifting or lowering process, the lifting or lowering command is stopped, so that the compressed air acting on the piston in the lifting control valve 13 is discharged from the exhaust port of the lifting solenoid valve 7 or the lowering solenoid valve 6. Then, the valve core returns to the middle position under the action of the spring force, cutting off the connection between the cylinder interface and other interfaces. The high-pressure oil in the cylinder stops flowing in or out, and the cylinder piston is in a stationary state (i.e., intermediate stop state).

[0074] As can be seen, the movement of the hydraulic cylinder can be stopped at any time, whether it is being lifted or lowered.

[0075] Furthermore, in one embodiment of the present invention, the drive-by-wire lifting control method for the unmanned off-highway wide-body dump truck further includes:

[0076] Limiting state: When the first lifting hydraulic cylinder 15 or the second lifting hydraulic cylinder 16 rises to the set lifting height, it will touch the limit valve 8, causing the valve core of the limit valve 8 to move, cutting off the air passage between the system air pressure and the lifting control valve 13, and causing the compressed air acting on the piston of the lifting control valve 13 to be discharged from the exhaust port of the limit valve 8. In this way, the valve core of the lifting control valve 13 will return to the middle position under the action of the spring force, cutting off the connection between the lifting cylinder interface and the oil pump interface, and the first lifting hydraulic cylinder 15 or the second lifting hydraulic cylinder 16 will stop rising.

[0077] The unmanned off-highway wide-body dump truck drive-by-wire lifting control system and method provided in this invention control the on / off of each air circuit through the power take-off solenoid valve, lifting solenoid valve, and lowering solenoid valve, thereby controlling the hydraulic oil circuit. This pneumatic-hydraulic control method achieves functions such as cargo box lifting and lowering, improving operational efficiency and equipment reliability, effectively reducing operating costs and safety risks. It solves the problems of existing lifting systems being unable to perform linear proportional control of the cargo box lifting or lowering process, resulting in uneven movements and significant impact on the vehicle frame. Simultaneously, it achieves more precise lifting control, improving system safety and reliability. Through signal interaction between the intelligent driving controller and the VCU, it realizes… Currently, through precise control of the air and oil circuits via electrical signals, and speed adjustment and limit functions achieved through sensor feedback, unmanned intelligent control and dynamic adjustment of the lifting process are realized, rather than simple opening and closing control. This enables precise control of the cargo box's lifting and lowering process, allowing adjustment of the lifting speed as needed, effectively avoiding impact on the chassis and extending its service life. Simultaneously, it can adjust the power take-off speed based on cargo box angle feedback, thereby adjusting the lifting speed in real time. Furthermore, it features comprehensive mid-stop and limit functions, making control more flexible, operation safer, and more adaptable. The mid-stop and limit functions enhance operational safety and convenience.

[0078] The embodiments of this disclosure have now been described in detail. To avoid obscuring the concept of this disclosure, some details known in the art have not been described. Those skilled in the art can fully understand how to implement the technical solutions disclosed herein based on the above description.

[0079] While specific embodiments of this disclosure have been described in detail by way of examples, those skilled in the art should understand that the examples are for illustrative purposes only and not intended to limit the scope of this disclosure. Those skilled in the art should understand that modifications can be made to the above embodiments or equivalent substitutions can be made to some technical features without departing from the scope and spirit of this disclosure. The scope of this disclosure is defined by the appended claims.

Claims

1. A drive-by-wire lifting control system for an unmanned off-highway wide-body dump truck, characterized in that, include: An air pump, a dryer, and an air tank are arranged sequentially. The air tank is connected in parallel to a power take-off (PTO) solenoid valve, a lowering solenoid valve, and a lifting solenoid valve. One end of each of the PTO, lowering, and lifting solenoid valves is connected to a high-drive signal from the vehicle controller, and the other end is grounded. The PTO solenoid valve is connected to a gearbox with a PTO assembly. The gearbox with a PTO assembly is sequentially connected to a power take-off shaft and a gear pump. The lifting solenoid valve is connected to a limit valve. The gear pump, the lowering solenoid valve, and the limit valve are each connected to a lifting control valve. The gear pump and the lifting control valve are connected to an oil tank. The lifting control valve is also connected in parallel to a first lifting hydraulic cylinder and a second lifting hydraulic cylinder.

2. The unmanned off-highway wide-body dump truck drive-by-wire lifting control system according to claim 1, characterized in that, The gas storage tank is connected to a main gas pipe, on which a first gas pipe, a second gas pipe, and a third gas pipe are respectively installed. The power take-off solenoid valve is installed on the first gas pipe, the lowering solenoid valve is installed on the second gas pipe, and the lifting solenoid valve is installed on the third gas pipe.

3. The unmanned off-highway wide-body dump truck drive-by-wire lifting control system according to claim 2, characterized in that, The power take-off solenoid valve is connected to the gearbox with power take-off assembly via a fourth air pipe; the lowering solenoid valve and the lifting solenoid valve are connected to the lifting control valve via a fifth air pipe; the lifting solenoid valve is connected to the limit valve via a sixth air pipe; and the limit valve is connected to the lifting control valve via a seventh air pipe.

4. The unmanned off-highway wide-body dump truck drive-by-wire lifting control system according to claim 1, characterized in that, The first lifting hydraulic cylinder and the second lifting hydraulic cylinder are symmetrically mounted on the left and right longitudinal beams of the vehicle frame; the gear pump is fixed on the gear pump mounting bracket.

5. The unmanned off-highway wide-body dump truck drive-by-wire lifting control system according to claim 1, characterized in that, The gear pump is connected to the oil tank via a first oil pipe; the gear pump is connected to the lifting control valve via a second oil pipe; the lifting control valve is connected to the first lifting hydraulic cylinder and the second lifting hydraulic cylinder via a three-way valve; the lifting control valve is connected to the three-way valve via a third oil pipe; and the lifting control valve is connected to the oil tank via a fourth oil pipe.

6. The unmanned off-highway wide-body dump truck drive-by-wire lifting control system according to claim 1, characterized in that, The unmanned off-highway wide-body dump truck drive-by-wire lifting control system also includes an intelligent driving controller and a cargo box angle sensor. The vehicle controller, the intelligent driving controller, and the cargo box angle sensor communicate with each other via a CAN network.

7. The unmanned off-highway wide-body dump truck drive-by-wire lifting control system according to claim 1, characterized in that, The gear pump is connected to a power take-off air source, the limit valve is connected to a lifting air source, and the lifting control valve is connected to a lowering air source.

8. A method for drive-by-wire lifting control of an unmanned off-highway wide-body dump truck using the system described in any one of claims 1-7, characterized in that, include: When the power take-off (PTO) is engaged, the lifting oil pump operates: When lifting the cargo box, the PTO solenoid valve is energized, connecting the PTO control air circuit. The gearbox engages with the PTO assembly, transmitting the motor power to the PTO and gear pump through the gearbox, causing the gear pump to rotate at high speed. The gear pump pumps hydraulic oil from the oil tank, and the high-pressure oil flows back to the oil tank through the oil passage inside the lifting solenoid valve, thus circulating in this way. Lifting state: When lifting the cargo box, the lifting solenoid valve is energized and the system air pressure flows through the lifting solenoid valve and the limit valve into the lifting control valve through the lifting interface. It acts on the cylinder piston of the lifting control valve, pushing the piston to the left and driving the valve core to the left, connecting the oil pump interface with the lifting cylinder interface. High-pressure oil enters the cylinder and lifts the cylinder. Descent state: When the cargo box is lowered, after the descent solenoid valve is energized, the system air pressure enters the lifting control valve through the descent interface via the descent solenoid valve. This pressure acts on the piston of the lifting control valve, pushing the piston to the right and causing the valve core to move to the right, connecting the lifting cylinder interface with the return oil interface. The high-pressure oil in the cylinder then flows back to the oil tank.

9. The drive-by-wire lifting control method for unmanned off-highway wide-body dump trucks according to claim 8, characterized in that, Before the power take-off solenoid valve is energized, the power take-off is connected, and the lifting oil pump operates as follows: The intelligent driving controller sends a lifting request CAN signal to the vehicle controller. First, it connects the transmission with the power take-off assembly to the lifting oil pump. The vehicle controller then determines the vehicle's status. Once the conditions are met, it outputs a high-drive signal to the power take-off solenoid valve to energize it. Before the lifting solenoid valve is energized, the lifting state includes: The intelligent driving controller sends a lifting command CAN signal to the vehicle controller, which then outputs a high-drive signal to the lifting solenoid valve to energize it. The lifting state also includes: If the lifting pressure exceeds the preset pressure threshold, the bypass relief valve will open. The initial rated speed of the power take-off (PTO) issued by the vehicle controller is 1200 r / min. During the lifting process, the cargo box angle sensor measures the lifting angle in real time and sends it to the vehicle controller and intelligent driving controller via the CAN network. This allows the intelligent driving controller to calculate the lifting speed based on the rate of change of the lifting angle. If it is necessary to increase the lifting speed, the intelligent driving controller sends an accelerator pedal opening signal to the vehicle controller, which then controls the PTO speed to increase. Within 5 degrees before the vehicle is fully lifted, the intelligent driving controller linearly reduces the throttle opening signal value. Before the descent solenoid valve is energized, the descent state includes: The intelligent driving controller sends a descent command CAN signal to the vehicle controller, and the vehicle controller outputs a high-drive signal to the descent solenoid valve to energize it.

10. The drive-by-wire lifting control method for unmanned off-highway wide-body dump trucks according to claim 8, characterized in that, The unmanned off-highway wide-body dump truck drive-by-wire lifting control method also includes: Intermittent Stop State: During the lifting or lowering process, the lifting or lowering command is stopped, so that the compressed air acting on the piston in the lifting control valve is discharged from the exhaust port of the lifting solenoid valve or the lowering solenoid valve. Then, the valve core returns to the middle position under the action of the spring force, cutting off the connection between the cylinder interface and other interfaces. The high-pressure oil in the cylinder stops flowing in or out, and the cylinder piston is in a stationary state. The unmanned off-highway wide-body dump truck drive-by-wire lifting control method also includes: Limit state: When the first or second lifting hydraulic cylinder rises to the set lifting height, it will touch the limit valve, causing the valve core of the limit valve to move, cutting off the air passage between the system air pressure and the lifting control valve, and causing the compressed air acting on the piston of the lifting control valve to be discharged from the exhaust port of the limit valve. In this way, the valve core of the lifting control valve will return to the middle position under the action of the spring force, cutting off the connection between the lifting cylinder interface and the oil pump interface, and the first or second lifting hydraulic cylinder will stop rising.

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