Alignment control method, electro-hydraulic steering system, steering system and multi-axle wheel type equipment

Abstract

The invention relates to the technical field of steering control, and discloses an alignment control method, an electro-hydraulic steering system, a steering system and multi-axle wheel type equipment, the electro-hydraulic steering system comprises a centering oil cylinder, an energy accumulator, a centering electromagnetic valve and an energy accumulator unloading valve, and the method comprises the steps that operation data of the multi-axle wheel type equipment are obtained; determining the current operation condition of the multi-axle wheel type equipment according to the operation data; if the current working condition is the maintenance working condition, an energy accumulator unloading valve is controlled to open a pressure relief oil way, and a centering electromagnetic valve is controlled to close a centering oil way, so that hydraulic oil in the energy accumulator flows to an oil return tank of the multi-axle wheel type equipment through the pressure relief oil way, and a centering oil cylinder loses centering power. The energy accumulator unloading valve is additionally arranged, so that high-pressure driving force of the energy accumulator can be eliminated under the maintenance working condition, the centering oil cylinder loses alignment power, a rear axle is forbidden to return, extrusion and collision damage to maintenance personnel near the axle in the return process is prevented from the source, and the safety and reliability of maintenance operation are improved.

Description

Technical Field

[0001] This invention relates to the field of steering control technology, specifically to a centering control method, an electro-hydraulic steering system, a steering system, and a multi-axle wheeled device. Background Technology

[0002] Taking a four-axle wheeled crane as an example, multi-axle wheeled cranes with electro-hydraulic steering systems typically use mechanical steering for the first two axles, with the steering wheel and steering linkage directly controlling the wheel steering, while the last two axles use electro-hydraulic power steering, i.e., an electro-hydraulic steering system.

[0003] To ensure vehicle driving safety, existing electro-hydraulic steering systems are generally equipped with accumulators. In the event of an unexpected power failure (such as a broken wiring harness, a controller malfunction, or an unexpected power outage of the vehicle), the high-pressure hydraulic oil stored inside the accumulator drives the centering cylinder to achieve forced automatic centering of the rear axle, ensuring that the vehicle can still drive safely.

[0004] However, this structure has obvious safety defects: when the vehicle is parked for maintenance, repair or chassis maintenance, if the steering wheel is not in the center position and the rear wheels have a certain steering angle, if the power to the whole vehicle is cut off, the electro-hydraulic steering system of the rear two axles will trigger the accumulator's forced return-to-center function due to power failure. The wheels will suddenly return to the center without warning, which can easily cause squeezing or collision injuries to maintenance personnel working or repairing near the axle, posing a significant safety hazard. Summary of the Invention

[0005] This invention provides a centering control method, an electro-hydraulic steering system, a steering system, and a multi-axle wheeled equipment to solve the problem that when a multi-axle wheeled equipment is parked for maintenance, the rear axle may force automatic centering due to accumulator pressure retention, which may affect the safety of maintenance personnel.

[0006] In a first aspect, the present invention provides a centering control method applied to a multi-axle wheeled equipment. The multi-axle wheeled equipment includes an electro-hydraulic steering system, which includes a centering cylinder, an accumulator, a centering solenoid valve, and an accumulator unloading valve. The method includes: acquiring operating data of the multi-axle wheeled equipment; determining the current operating condition of the multi-axle wheeled equipment based on the operating data, wherein the operating condition includes at least a maintenance condition; if the current condition is a maintenance condition, controlling the accumulator unloading valve to open the pressure relief oil circuit and controlling the centering solenoid valve to close the centering oil circuit, so that the hydraulic oil in the accumulator flows to the return oil tank of the multi-axle wheeled equipment through the pressure relief oil circuit, and the centering cylinder loses its centering power.

[0007] The alignment control method provided by this invention adds an accumulator unloading valve to the electro-hydraulic steering system. Based on the operating data of the multi-axle wheel equipment, the current operating condition is determined. If the current condition is maintenance, the accumulator unloading valve is actively controlled to open the pressure relief oil circuit, so that the hydraulic oil in the accumulator flows to the return oil tank of the multi-axle wheel equipment through the pressure relief oil circuit, completely eliminating the high-pressure driving force of the accumulator. Thus, under maintenance conditions, the alignment cylinder loses the alignment power, avoiding the rear axle from automatically returning to center during maintenance. This fundamentally prevents squeezing and collision injuries to maintenance personnel near the axle during the centering process, improving the safety and reliability of maintenance operations.

[0008] In one optional implementation, the operating condition further includes: normal driving condition, and the method further includes: if in normal driving condition, controlling the centering solenoid valve to close the centering oil circuit and controlling the accumulator unloading valve to close the pressure relief oil circuit, so that the centering cylinder is in a floating state and loses the centering power.

[0009] This invention closes the alignment oil circuit and the pressure relief oil circuit under normal driving conditions, so that the alignment cylinder is in a floating state. The rear axle can follow the front axle to turn without generating additional steering resistance, ensuring driving and steering flexibility, while maintaining the pressure of the accumulator and not affecting the system's response capability.

[0010] In an optional implementation, the operating conditions further include: high-speed driving condition and parking condition. The method further includes: if the current condition is high-speed driving condition or parking condition, controlling the centering solenoid valve to open the centering oil circuit and controlling the accumulator unloading valve to close the pressure relief oil circuit, so that the hydraulic oil in the accumulator flows to the centering cylinder, and the centering cylinder performs centering lock.

[0011] This invention opens the alignment oil circuit and maintains the pressure of the accumulator under high-speed driving and parking conditions, so that the alignment cylinder can achieve alignment lock, thereby ensuring the rear axle is stably returned to center when driving at high speed, improving the straight driving stability of the vehicle, and automatically locking the rear axle position when parking to prevent wheel deflection and facilitate the next start-up.

[0012] In some optional implementations, the operating data includes at least: vehicle speed signal, engine speed signal, and maintenance signal; determining the current operating condition of the multi-axle wheeled equipment based on the operating data includes: judging the current operating condition of the multi-axle wheeled equipment based on the vehicle speed signal, engine speed signal, and maintenance signal; if the vehicle speed signal is not zero and is lower than a preset speed threshold, and the engine is running, then it is determined that the current operating condition is normal; if the vehicle speed signal is higher than a preset speed threshold, and the engine is running, then it is determined that the current operating condition is high-speed; if the vehicle speed signal is zero, the engine is stopped or idling, and no maintenance signal is detected, then it is determined that the current operating condition is stopped; if the vehicle speed signal is zero, the engine is stopped or idling, and a maintenance signal is detected, then it is determined that the current operating condition is under maintenance.

[0013] This invention combines vehicle speed, engine speed, and maintenance signals to comprehensively determine the operating condition, which can improve the accuracy and reliability of operating condition identification, accurately distinguish between normal driving, high-speed driving, parking, and maintenance conditions, and achieve refined and adaptive control under different operating conditions. It effectively prevents problems such as unwarranted depressurization of the accumulator caused by misjudgment of maintenance conditions and safety hazards caused by misjudgment of driving conditions.

[0014] Secondly, the present invention provides an electro-hydraulic steering system, comprising: a hydraulic part and an electronic control part; the hydraulic part includes: a centering cylinder, an accumulator, a centering solenoid valve, and an accumulator unloading valve, the accumulator being connected to the centering solenoid valve, the centering solenoid valve being connected to one end of the centering cylinder via a centering inlet line, the other end of the centering cylinder being connected to the centering solenoid valve via a centering return line, the centering solenoid valve being connected to the return oil tank of a multi-axle wheeled device, one end of the accumulator unloading valve being connected to the accumulator, and the other end of the accumulator unloading valve being connected to the return oil tank via an unloading return line; the electronic control part includes: a steering controller, the steering controller being electrically connected to the centering solenoid valve and the accumulator unloading valve, for executing the centering control method of the first aspect or any corresponding embodiment described above.

[0015] The electro-hydraulic steering system provided by this invention adds an accumulator unloading valve to the electro-hydraulic steering system. The steering controller is directly electrically connected to the centering solenoid valve and the accumulator unloading valve. Then, based on the centering solenoid valve, the high-pressure energy of the accumulator drives the centering cylinder to force centering. Based on the accumulator unloading valve, the high-pressure driving force of the accumulator is eliminated, and the centering cylinder loses the centering power. This realizes the integrated design of the centering control method and hardware system. Moreover, the addition of the unloading valve component does not require large-scale modification of the original electro-hydraulic steering system. The system modification is small and the modification cost is low. It is suitable for various multi-axle wheel equipment.

[0016] In some alternative implementations, the hydraulic components further include a throttle valve connected in series in the unloading return line between the accumulator and the accumulator unloading valve.

[0017] This invention connects a throttle valve in series on the unloading return oil line between the accumulator and the accumulator unloading valve. This effectively regulates the depressurization rate of the accumulator, avoids hydraulic shock caused by instantaneous pressure release from the accumulator, protects hydraulic pipelines, valves, sensors, and other hydraulic components, and extends the overall service life of the electro-hydraulic steering system. At the same time, the throttle valve can limit the flow rate when the accumulator unloading valve fails and remains open, ensuring that the system can still maintain basic pressure reserves and preventing the steering system from failing due to complete depressurization of the accumulator. This achieves fault redundancy protection and further improves the operational reliability of the system.

[0018] In some alternative embodiments, the hydraulic system further includes: a steering hydraulic pump, a steering cylinder, a steering axle, and a steering proportioning solenoid valve; the steering controller is electrically connected to the steering proportioning solenoid valve; the steering hydraulic pump is connected to the steering proportioning solenoid valve, the steering proportioning solenoid valve is connected to the steering cylinder via a main oil inlet line, and the steering cylinder is mechanically connected to the steering axle.

[0019] This invention controls the steering ratio solenoid valve to precisely adjust the flow rate and pressure of hydraulic oil flowing to the steering cylinder, thereby achieving stepless steering control of the steering axle and improving the steering accuracy and smoothness of operation of multi-axle wheeled equipment.

[0020] In some optional implementations, the electronic control unit further includes: an angle sensor and a pressure sensor, with the steering controller connected to the angle sensor and the pressure sensor respectively; the angle sensor is located on the steering axle and is used to collect the steering angle of the steering axle; the pressure sensor is located in the outlet oil circuit of the accumulator and is used to collect the pressure value of the accumulator.

[0021] This invention utilizes angle and pressure sensors to achieve real-time data acquisition of steering axle steering angle and accumulator pressure, providing data support for steering controller condition determination and precise control. The steering angle assists the steering controller in adjusting the steering ratio solenoid valve, enabling precise steering of the steering axle and improving steering control accuracy. Monitoring accumulator pressure allows for timely detection of accumulator leaks, insufficient oil supply, and other faults, providing data for preventative system maintenance. It also ensures that the accumulator provides the required pressure under all operating conditions, preventing safety hazards caused by abnormal pressure.

[0022] Thirdly, the present invention provides a steering system, comprising: a hydraulic steering system and an electro-hydraulic steering system according to the second aspect above or any corresponding embodiment thereof, wherein the hydraulic steering system is applied to the front axle steering control of a multi-axle wheeled device, and the electro-hydraulic steering system is applied to the rear axle steering control of the multi-axle wheeled device.

[0023] The steering system provided by this invention adopts a separate control structure where a hydraulic steering system controls the front axle and an electro-hydraulic steering system controls the rear axle. This structure can adapt to the steering requirements of multi-axle wheeled equipment. The front axle hydraulic steering ensures the reliability of basic steering, while the rear axle electro-hydraulic steering enables precise follow-up steering and centering lock. The two work together to improve the overall steering flexibility and driving stability of the equipment. At the same time, the rear axle electro-hydraulic steering system has a safety function for maintenance and pressure relief. This adds safety protection for maintenance operations while retaining the original steering performance of the entire steering system, solving the safety pain points of traditional multi-axle steering systems during maintenance and improving the safety and practicality of the entire steering system.

[0024] Fourthly, the present invention provides a multi-axle wheeled device including the steering system described in the third aspect above.

[0025] This invention applies a steering system that combines safety, reliability, and precision to multi-axle wheeled equipment. It retains the original good steering and driving performance of the equipment while completely eliminating the safety hazards of the steering system during equipment maintenance and repair, thus improving the safety of the equipment throughout its entire life cycle. At the same time, the steering system is easy to modify and highly versatile, requiring no large-scale adjustments to the overall structure of the multi-axle wheeled equipment. It can be directly adapted to the production and modification of various types of multi-axle wheeled equipment, thereby enhancing the product competitiveness of the equipment. Attached Figure Description

[0026] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the steering system according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the first type of alignment control method according to an embodiment of the present invention; Figure 3 This is a schematic diagram of a second type of alignment control method according to an embodiment of the present invention; Figure 4 This is a structural block diagram of the alignment control device according to an embodiment of the present invention; Figure 5 This is a schematic diagram of the hardware structure of the steering controller according to an embodiment of the present invention.

[0028] Explanation of reference numerals in the attached figures: 1-Steering system; 10-Hydraulic steering system; 20-Electro-hydraulic steering system; 201-Centering cylinder; 202-Accumulator; 203-Center solenoid valve; 204-Accumulator unloading valve; 205-Throttle valve; 206-Steering hydraulic pump; 207-Steering cylinder; 208-Steering axle; 209-Steering proportion solenoid valve; 210-Steering angle sensor; 211-Pressure sensor. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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, not all embodiments. 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.

[0030] It is understood that before using the technical solutions disclosed in the various embodiments of the present invention, users should be informed of the types, scope of use, and usage scenarios of the personal information involved in the present invention and their authorization should be obtained in accordance with relevant laws and regulations through appropriate means.

[0031] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0032] The electro-hydraulic steering system relies on accumulators to supply oil to the centering cylinders. However, when the vehicle is parked for maintenance or repair, and the steering wheel is not in the center position with the tires at an angle, a power outage could force the tires of the rear electro-hydraulic steering axles back to center, potentially injuring personnel working near the chassis axles. In the truck crane industry, only Leebherr uses a dual-pump axle drive to independently supply oil to the centering cylinders. When the crane is in operation, the pump outputs pressure to the centering cylinders; when parked, the pump stops, leaving no pressure output to the centering cylinders. This fundamentally avoids the drawbacks of relying on accumulators for centering. However, this solution requires power take-off interfaces on the crane's transmission components, such as the transfer case and axles, and also necessitates the addition of a dual-pump pump. This results in high system complexity and cost, and makes it unsuitable for smaller tonnage vehicles without transfer cases.

[0033] According to an embodiment of the present invention, a steering system embodiment is provided, applied to multi-axle wheeled equipment, such as a multi-axle wheeled crane, as... Figure 1 As shown, the steering system 1 includes a hydraulic steering system 10 and an electro-hydraulic steering system 20. The hydraulic steering system 10 is used for front axle steering control of a multi-axle wheeled vehicle, and the electro-hydraulic steering system 20 is used for rear axle steering control of the multi-axle wheeled vehicle. The electro-hydraulic steering system 20 includes a hydraulic part and an electronic control part. The hydraulic part includes a centering cylinder 201, an accumulator 202, a centering solenoid valve 203, and an accumulator unloading valve 204. The accumulator 202 is connected to the centering solenoid valve 203, and the centering solenoid valve 203... 3. The centering cylinder 201 is connected to one end of the centering inlet oil line through the centering oil inlet line. The other end of the centering cylinder 201 is connected to the centering solenoid valve 203 through the centering return oil line. The centering solenoid valve 203 is connected to the return oil tank of the multi-axle wheel equipment. One end of the accumulator unloading valve 204 is connected to the accumulator 202. The other end of the accumulator unloading valve 204 is connected to the return oil tank through the unloading return oil line. The electrical control part includes: a steering controller, which is electrically connected to the centering solenoid valve 203 and the accumulator unloading valve 204.

[0034] Specifically, in this embodiment of the invention, the accumulator unloading valve 204 is a newly added component compared to the original structure of the electro-hydraulic steering system 20. Taking a four-axle crane as an example, the hydraulic steering system 10 is adapted to the 1st and 2nd axles of the four-axle crane and is a mechanical hydraulic steering structure. It directly drives the front axle to steer through the steering wheel and steering linkage, serving as the basic steering unit of the equipment and realizing basic steering control during equipment travel and operation. The electro-hydraulic steering system 20 is adapted to the 3rd and 4th axles of the four-axle crane and is an electro-hydraulic steering structure. It receives the steering signal from the hydraulic steering system 10 and realizes the rear axle to follow the steering. It also has a rear axle centering lock function and, based on the newly added accumulator unloading valve 204, has the function of maintenance pressure relief. Therefore, the electro-hydraulic steering system 20, as an auxiliary steering and safety control unit of the equipment, solves the maintenance safety hazards of the traditional rear axle electro-hydraulic steering system.

[0035] Among them, the electro-hydraulic steering system 20 is the core improved component of the present invention. It is divided into a hydraulic part and an electronic control part. The hydraulic part adds an accumulator unloading valve 204 and a matching unloading return oil pipeline to the original centering cylinder 201, accumulator 202 and centering solenoid valve 203. The electronic control part is precisely electrically connected to the hydraulic components to realize intelligent control under various working conditions.

[0036] The hydraulic section is the power actuator of the electro-hydraulic steering system 20, consisting of a centering cylinder 201, an accumulator 202, a centering solenoid valve 203, an accumulator unloading valve 204, various hydraulic pipelines, and a return oil tank built into the multi-axle wheeled equipment. All components are connected by sealed hydraulic pipelines, and hydraulic oil is the power medium. Specifically, the centering cylinder 201 is a linear hydraulic actuator, directly mechanically connected to the 3rd and 4th axle steering axles of the four-axle crane. Its extension and retraction can directly drive the 3rd and 4th axle steering axles to complete the centering, return, and locking actions, making it the core actuator for rear axle centering and locking. The centering cylinder 201 has a dual-port structure, with an inlet and a return port at each end, connected to the centering inlet and return oil pipelines respectively. The extension and retraction actions are achieved through the inflow and outflow of hydraulic oil.

[0037] Accumulator 202 is a hydraulic energy storage element that serves as an emergency pressure source for electro-hydraulic steering system 20. It has pressure holding and energy storage functions and can release stored high-pressure hydraulic oil to provide power to centering cylinder 201 when the equipment loses power or the hydraulic pump stops supplying oil. The oil outlet of accumulator 202 has a multi-port structure. One port is sealed to the oil inlet of centering solenoid valve 203 to provide high-pressure hydraulic oil to the centering oil circuit. The other port is sealed to the oil inlet of accumulator unloading valve 204 to provide hydraulic oil to the unloading oil circuit, thereby realizing pressure relief.

[0038] The centering solenoid valve 203 is a two-position on / off hydraulic solenoid valve. As the core control element of the centering oil circuit, it is set in the alignment oil circuit between the accumulator 202 and the centering cylinder 201. Its oil inlet end is connected to the oil outlet of the accumulator 202, and its working end is connected to the oil inlet of the centering cylinder 201 through the centering oil inlet pipe and to the oil return port of the centering cylinder 201 through the centering oil return pipe. The oil return end is directly and sealed to the oil return tank of the four-bridge crane. The centering solenoid valve 203 can switch the oil circuit on / off state by energizing and de-energizing, so as to realize the pressure supply and pressure relief control of the centering cylinder 201.

[0039] The accumulator unloading valve 204 is a newly added core hydraulic component in this embodiment of the invention. It is a two-position on / off hydraulic solenoid valve and serves as the sole control element of the unloading oil circuit. It is independently installed on the hydraulic pipeline between the accumulator 202 and the return oil tank. Its inlet end is sealed to the outlet of the accumulator 202, and its return end is sealed to the return oil tank of the four-axle crane through a dedicated unloading return oil pipeline. No other hydraulic components are connected in series or parallel to this unloading return oil pipeline. The accumulator unloading valve 204 has only two working states: "on" and "off". When energized, the valve port opens and the unloading oil circuit is connected. When de-energized, the valve port closes and the unloading oil circuit is cut off. It is designed with an independent pressure relief channel for the accumulator 202 and does not interfere with the original alignment oil circuit.

[0040] Furthermore, such as Figure 1 As shown, in this embodiment of the invention, a throttle valve 205 is also deployed in the unloading return oil pipeline between the accumulator unloading valve 204 and the return oil tank. The throttle valve 205 can adopt a fixed flow throttle structure or a proportional throttle valve. Its flow orifice diameter is matched with the volume of the accumulator and the system working pressure. It can accurately control the flow rate of hydraulic oil in the unloading oil circuit. There is no separate electrical control interface. The flow rate is adjusted only through hydraulic damping. The structure is simple and the reliability is high. It is connected to the unloading return oil pipeline with a sealed thread, which is convenient for installation and replacement.

[0041] In summary, the hydraulic lines for achieving centering control include the centering inlet line, the centering return line, and the unloading return line, all of which are high-pressure hydraulic lines. They are adapted to the oil ports of each hydraulic component and sealed. The unloading return line is a new line that is only adapted to the pressure relief requirements of the accumulator unloading valve 204. The line diameter is matched with the pressure relief flow of the accumulator 202. All hydraulic lines are arranged along the chassis of the multi-axle wheeled equipment to avoid interference with other mechanical components.

[0042] The return oil tank is a hydraulic oil storage unit built into the multi-axle wheel equipment. As the hydraulic oil recovery end of the electro-hydraulic steering system 20, it receives the hydraulic oil returned by the centering solenoid valve 203 and the accumulator unloading valve 204, realizing the recycling of hydraulic oil.

[0043] In some alternative implementations, the electronic control component is the intelligent control unit of the electro-hydraulic steering system 20, with the steering controller (not included in...) at its core. Figure 1 (As shown in the image), the steering controller achieves a precise one-to-one electrical connection with the centering solenoid valve 203 and the accumulator unloading valve 204 in the hydraulic system, transmitting signals and power via wires and wiring harness plugs. The steering controller can receive operating data such as vehicle speed, engine speed, maintenance signals, and accumulator pressure from multi-axle wheeled equipment, and outputs electrical control signals after determining the working condition. The output of the steering controller has two independent control interfaces, which are electrically connected to the electromagnetic coils of the centering solenoid valve 203 and the accumulator unloading valve 204 respectively, allowing independent control of the on / off state of the two solenoid valves, realizing independent control of the centering oil circuit and the unloading oil circuit without interference.

[0044] In this embodiment of the invention, the accumulator unloading valve 204 is a newly added component, arranged independently in parallel. Its oil inlet is directly connected to the oil outlet of the accumulator 202, and its oil return is connected back to the oil tank through an independent unloading return oil pipeline. No changes are made to the structure and connection relationship of the original centering cylinder 201, accumulator 202, and centering solenoid valve 203, nor is the hydraulic resistance of the original centering oil circuit increased. The electronic control part only adds a control interface to the steering controller to connect to the accumulator unloading valve 204. The control logic of the original centering solenoid valve 203 remains unchanged, achieving seamless adaptation between the new structure and the original structure. No large-scale modification of the electro-hydraulic steering system 20 is required, balancing the improvement effect and the modification cost.

[0045] In some alternative embodiments, the accumulator unloading valve 204 can be replaced by a pneumatic valve, a hydraulic valve, or any other element that can release the pressure inside the accumulator, and the throttle valve 205 can be replaced by any element that can adjust the flow rate, such as a proportional throttle valve, a damping valve, or a flow valve, without any specific limitation.

[0046] In some alternative implementations, such as Figure 1 As shown, the original structure of the electro-hydraulic steering system also includes: steering hydraulic pump 206, steering cylinder 207, steering axle 208, and steering proportion solenoid valve 209, which together constitute the power execution branch of the rear axle steering. It is independent of and does not interfere with the centering and unloading branch (centering cylinder 201, accumulator 202, centering solenoid valve 203, accumulator unloading valve 204, and throttle valve 205).

[0047] Among them, the steering hydraulic pump 206 is driven by the engine or power take-off of the multi-axle wheel equipment, providing a high-pressure hydraulic power source for the steering execution branch; its oil inlet is connected to the equipment return oil tank through the oil suction pipe, and its oil outlet is sealed to the P port (oil inlet) of the steering proportional solenoid valve 209 through the high-pressure oil supply pipe, continuously delivering high-pressure hydraulic oil.

[0048] The steering proportional solenoid valve 209 is an electro-hydraulic proportional control valve and is the core of steering flow and pressure regulation. Its P port is connected to the steering hydraulic pump 206, its T port (return port) is connected to the equipment return oil tank through the return oil pipeline, and its A / B ports (working ports) are connected to the rodless chamber / rod chamber of the steering cylinder 207 through the main oil inlet pipeline, respectively. The electromagnetic coil of the steering proportional solenoid valve 209 is electrically connected to the steering controller through a shielded wiring harness. It can steplessly adjust the valve core opening according to the PWM signal output by the controller, and precisely control the flow and direction of hydraulic oil to the steering cylinder 207.

[0049] The steering cylinder 207 is a double-acting linear hydraulic cylinder. Its cylinder end is hinged to the rear axle frame, and its piston rod end is rigidly hinged to the steering arm of the steering axle 208. The rodless chamber / rod chamber of the steering cylinder 207 are connected to the A / B ports of the steering proportioning solenoid valve 209 through the main oil inlet line, respectively. The hydraulic oil pushes the piston to extend and retract, directly driving the steering axle 208 to rotate around the kingpin, thereby realizing the steering action of the rear axle.

[0050] The steering axle 208 is the rear axle steering carrier of the multi-axle wheeled equipment, with wheels installed at both ends; the extension and retraction stroke of the steering cylinder 207 is linearly related to the steering angle of the steering axle 208, ensuring the accurate transmission of steering actions.

[0051] Furthermore, all pipelines in the steering execution branch are also high-pressure hydraulic oil pipes, arranged along the equipment chassis, and physically isolated from the pipelines of the centering and unloading branch to avoid hydraulic interference; the T port of the steering proportional solenoid valve 209 and the return oil chamber of the steering cylinder 207 are all connected to the equipment return oil tank through the return oil pipeline to realize the circulation cooling and filtration of hydraulic oil, ensuring the cleanliness and working stability of the system.

[0052] In some alternative implementations, such as Figure 1 As shown, the original structure of the electro-hydraulic steering system also includes: an angle sensor 210 and a pressure sensor 211, with the steering controller connected to both the angle sensor 210 and the pressure sensor 211. The angle sensor 210 is mounted on the steering axle 208, for example, directly fixed to the steering knuckle / steering arm of the steering axle 208, rigidly connected to the steering rotation component of the steering axle 208, and used to collect the steering angle of the steering axle 208. The detection shaft of the angle sensor 210 is coaxially linked with the steering kingpin of the steering axle 208. When the steering axle 208 undergoes any angle of steering movement, the angle sensor 210 can move synchronously to ensure that the collected steering angle is completely consistent with the actual posture of the steering axle. The steering angle data collected by the angle sensor 210 is fed back to the steering controller in real time, compared with the front axle steering command, providing a precise basis for the steering controller to adjust the valve core opening of the steering ratio solenoid valve 209, realizing the follow-up closed-loop control of the rear axle steering.

[0053] Pressure sensor 211 is fixedly installed at the outlet main oil line joint of accumulator 202 using a threaded sealing connection. It is located upstream of throttle valve 205 and at the front end of the oil line of centering solenoid valve 203 and accumulator unloading valve 204, directly contacting the high-pressure hydraulic oil output by accumulator 202. It can collect the real-time hydraulic pressure of the outlet oil line of accumulator 202. The installation oil line of pressure sensor 211 is the common outlet oil line of accumulator 202, which can simultaneously detect the hydraulic pressure of the centering oil line and the unloading oil line. There is no need to arrange a separate detection oil line, and it is seamlessly adapted to the existing hydraulic pipeline without increasing the complexity of the oil line.

[0054] The electro-hydraulic steering system provided by this invention adds an accumulator unloading valve to the electro-hydraulic steering system. The steering controller is directly electrically connected to the centering solenoid valve and the accumulator unloading valve. Then, based on the centering solenoid valve, the high-pressure energy of the accumulator drives the centering cylinder to force centering. Based on the accumulator unloading valve, the high-pressure driving force of the accumulator is eliminated, and the centering cylinder loses the centering power. This realizes the integrated design of the centering control method and hardware system. Moreover, the addition of the unloading valve component does not require large-scale modification of the original electro-hydraulic steering system. The system modification is small and the modification cost is low. It is suitable for various multi-axle wheel equipment.

[0055] Furthermore, based on the structure of the electro-hydraulic steering system 20 described above, this embodiment of the invention provides a centering control method, which actively reduces the pressure of the accumulator 202 to zero during maintenance operations to avoid squeezing or collision injuries to maintenance personnel near the axle caused by forced centering.

[0056] According to an embodiment of the present invention, a positive control method embodiment is provided. It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. Furthermore, although a logical order is shown in the flowchart, in some cases, the steps shown or described may be executed in a different order than that shown here.

[0057] This embodiment provides a positive control method that can be used in the aforementioned multi-axle wheeled equipment, such as a multi-axle wheeled crane. Figure 2 This is a flowchart of the alignment control method according to an embodiment of the present invention, such as... Figure 2 As shown, the process includes the following steps: Step S201: Obtain the operating data of the multi-axle wheeled equipment.

[0058] Specifically, in this embodiment of the invention, the steering controller of the electro-hydraulic steering system 20 is used as the main actuator, and the angle sensor 210 and pressure sensor 211 of the electro-hydraulic steering system 20, as well as the vehicle control system of the multi-axle wheeled equipment, such as the engine ECU, vehicle speed sensor, and maintenance switch, are coordinated to acquire multi-dimensional operating data of the multi-axle wheeled equipment in real time.

[0059] In this embodiment of the invention, the collected operating data is the core basis for determining the operating condition, covering three categories: equipment status signals, system pressure signals, and manual trigger signals. The collection methods and transmission paths of each data are as follows: Vehicle speed signal is collected in real time by the equipment's vehicle speed sensor and transmitted to the steering controller via the CAN bus, reflecting the current driving speed of the equipment; Engine speed signal is collected in real time by the equipment's engine ECU and transmitted to the steering controller via the CAN bus, reflecting the engine's running / stopping / idling status; Accumulator pressure signal is collected in real time by the pressure sensor 211 of the electro-hydraulic steering system 20, converting the hydraulic pressure into a standard electrical signal and transmitting it to the steering controller via the shielded wiring harness, reflecting the real-time pressure holding status of the accumulator 202; The maintenance signal is a manually triggered switch signal controlled by the maintenance switch in the equipment's cab / chassis maintenance area. When maintenance personnel start work, they close the maintenance switch, and the steering controller receives a high-level maintenance signal, which serves as the core trigger condition for determining the maintenance condition; The steering angle signal is collected in real time by the steering angle sensor 210, reflecting the current attitude of the 3-4 axle steering axle, serving as an auxiliary judgment signal to avoid malfunction of the steering axle during pressure relief.

[0060] Step S202: Determine the current operating condition of the multi-axle wheeled equipment based on the operating data. The operating condition includes at least the maintenance condition.

[0061] Specifically, in this embodiment of the invention, after acquiring multi-dimensional operating data such as vehicle speed, engine speed, accumulator pressure, and maintenance signals, the steering controller will perform comprehensive analysis and logical verification of the collected data according to the pre-set operating condition judgment logic, so as to accurately determine the current operating condition of the equipment and provide core basis for the action control of the electro-hydraulic steering system.

[0062] Taking a four-axle crane as a typical example, when critical components such as the axle, chassis, and steering system malfunction and require repair, the work must be carried out with the equipment completely stopped. However, due to the limitations of the electro-hydraulic steering system's original alignment logic based on accumulators, after the equipment stops, the high-pressure hydraulic oil in the accumulator drives the alignment cylinder, causing the rear axle to automatically complete a forced alignment action. When the rear axle is in the correct position, core maintenance components such as the steering knuckle, steering arm, tie rod, hydraulic oil pipe joints, and solenoid valve body are obstructed by components such as the chassis frame and suspension brackets, creating blind spots for maintenance personnel. Maintenance personnel cannot directly observe the fault location, nor can they easily reach in to perform disassembly, tightening, and testing operations, failing to meet the spatial requirements of actual maintenance work.

[0063] To address this issue, maintenance personnel typically adjust the rear axle of a four-axle crane to a certain angle during inspections. This axle deflection exposes the areas to be inspected, widens component gaps, and creates ample and safe working space for maintenance operations. It also accommodates the operational needs of tasks such as steering cylinder seal testing, steering mechanism clearance checks, and solenoid valve and sensor adjustments, facilitating comprehensive inspection and repair of steering hydraulic components and mechanical connections. During this process, it is crucial to maintain the adjusted deflection angle of the rear axle at all times to prevent it from returning to its normal position and interfering with maintenance work. However, in traditional systems, unexpected power outages can cause the accumulator to force the rear axle back to its normal position, potentially resulting in injuries such as crushing or collisions to maintenance personnel working near the chassis axle, posing a serious safety hazard.

[0064] Based on this, in order to fundamentally avoid this safety hazard and protect the personal safety of maintenance personnel, the embodiments of this invention are specifically designed to add a maintenance working condition for multi-axle wheeled equipment such as four-axle cranes, and set a dedicated control logic for prohibiting the rear axle from alignment under this working condition. Through precise working condition judgment and corresponding pressure relief control, the power source for forced alignment of the rear axle is cut off, so that the rear axle can stably maintain the deflection angle required for maintenance, allowing maintenance work to be carried out in a safe and interference-free environment.

[0065] In some optional implementations, in addition to preset maintenance conditions, the embodiments of the present invention are also adapted to normal driving conditions, high-speed driving conditions and conventional parking conditions throughout the entire service life of multi-axle wheeled equipment. Each condition is determined by the steering controller based on multi-dimensional operating data and matched with dedicated steering control logic to adapt to the steering and safety requirements of different usage scenarios of the equipment.

[0066] The normal driving condition is the core condition for the equipment's regular driving and low-speed operation. Under this condition, it is necessary to ensure that the centering cylinder is in a floating state and does not interfere with the steering. The steering controller receives the steering signal from the front axle and the data from the rear axle angle sensor. It precisely adjusts the hydraulic oil flow through the steering ratio solenoid valve to realize the synchronous steering of the rear axle with the front axle, ensuring the flexibility and smoothness of the equipment's steering.

[0067] High-speed driving mode is a special mode for long-distance high-speed transfer of equipment. Under this mode, it is necessary to ensure that the high-pressure oil of the accumulator enters the centering cylinder to drive the rear axle to be forcibly centered and locked. At the same time, the steering ratio solenoid valve is closed to cut off the steering power of the rear axle, so as to avoid the rear axle from wagging or offset when driving at high speed, thereby improving the stability and safety of the equipment at high speed.

[0068] The parking condition refers to the temporary shutdown of the equipment, waiting for operation, and non-maintenance shutdown. In this condition, the accumulator releases high-pressure oil to push the centering cylinder to force the rear axle to return to the center, keeping the tires in a straight line and preventing the equipment from slipping or becoming unstable due to tire misalignment. At the same time, the accumulator maintains basic pressure to ensure that the equipment can quickly enter the driving state when it is restarted.

[0069] Step S203: If the current condition is under maintenance, control the accumulator unloading valve to open the pressure relief oil circuit and control the centering solenoid valve to close the centering oil circuit, so that the hydraulic oil in the accumulator flows to the return oil tank of the multi-axle wheel equipment through the pressure relief oil circuit, and the centering cylinder loses the centering power.

[0070] Specifically, in this embodiment of the invention, if the steering controller detects that the vehicle speed signal is zero, the engine is stopped or idling, and a maintenance signal is detected, it determines that the current condition is under maintenance. Then, the steering controller immediately triggers the dedicated pressure relief control logic, and achieves pressure relief of the accumulator by precisely controlling the action of the hydraulic components, thereby cutting off the power source of the centering cylinder from the root and ensuring that the rear axle maintains the deflection angle required for maintenance.

[0071] In this embodiment of the invention, a dedicated pressure relief control logic is set, such as... Figure 1 As shown, an accumulator unloading valve 204 and a throttle valve 205 are added to the original structure of the electro-hydraulic steering system 20. When the pressure relief control logic is triggered, the steering controller outputs a high-level energizing signal to the solenoid coil of the accumulator unloading valve 204, thereby opening the pressure relief oil circuit. The high-pressure hydraulic oil in the accumulator 202, after the flow rate is regulated by the throttle valve, slowly flows back to the return oil tank through the unloading oil circuit, and the pressure of the accumulator 202 is gradually reduced to 0MPa. At the same time, the centering solenoid valve 203 is kept in the energized state, and the centering oil circuit is closed, so that the hydraulic oil in the accumulator 202 cannot enter the centering cylinder 201. At this time, the centering cylinder 201 loses the high-pressure oil source of the accumulator 202 and completely loses the centering power. It will stably maintain the rear axle deflection angle pre-adjusted by the maintenance personnel and will not have any forced return to centering action. This provides sufficient working space for the maintenance of the chassis, axle, and steering system, and completely eliminates the risk of squeezing and collision injury to maintenance personnel caused by the axle return to centering in the traditional system. After maintenance is completed, the maintenance signal is turned off, the accumulator unloading valve 204 is de-energized and closed, the accumulator 202 resumes pressure maintenance, and the system automatically returns to normal shutdown conditions, waiting for the equipment to start again.

[0072] Therefore, in this embodiment of the invention, the accumulator unloading valve 204 is a two-position on / off solenoid valve. After being energized, it realizes the valve port switching and is the core control element for the pressure relief oil circuit. The other valves remain in their predetermined states to avoid interfering with the pressure relief action and to ensure the simplicity and stability of the pressure relief process.

[0073] Furthermore, if the accumulator unloading valve 204 fails to open, the throttle valve 205 connected in series in the unloading oil circuit can form a continuous flow restriction to prevent the accumulator pressure from being lost rapidly and uncontrollably, ensuring that the electro-hydraulic steering system can still maintain basic pressure reserves under fault conditions and preventing the steering system from completely failing; at the same time, the steering controller can identify the fault in a timely manner and issue an alarm through real-time data from the pressure sensor, taking into account both the pressure relief safety during maintenance and the overall operational reliability of the system.

[0074] The alignment control method provided by this invention adds an accumulator unloading valve to the electro-hydraulic steering system. Based on the operating data of the multi-axle wheel equipment, the current operating condition is determined. If the current condition is maintenance, the accumulator unloading valve is actively controlled to open the pressure relief oil circuit, so that the hydraulic oil in the accumulator flows to the return oil tank of the multi-axle wheel equipment through the pressure relief oil circuit, completely eliminating the high-pressure driving force of the accumulator. Thus, under maintenance conditions, the alignment cylinder loses the alignment power, avoiding the rear axle from automatically returning to center during maintenance. This fundamentally prevents squeezing and collision injuries to maintenance personnel near the axle during the centering process, improving the safety and reliability of maintenance operations.

[0075] This embodiment provides a positive control method that can be used in the aforementioned multi-axle wheeled equipment, such as a multi-axle wheeled crane. Figure 3 This is a flowchart of the alignment control method according to an embodiment of the present invention, such as... Figure 3 As shown, the process includes the following steps: Step S301: Obtain the operating data of the multi-axle wheeled equipment. For details, please refer to [link to relevant documentation]. Figure 2 Step S201 of the illustrated embodiment will not be described again here.

[0076] Step S302: Determine the current operating condition of the multi-axle wheeled equipment based on the operating data. The operating condition includes at least the maintenance condition. For details, please refer to [link to relevant documentation]. Figure 2 Step S202 of the illustrated embodiment will not be described again here.

[0077] Step S303: If the current operation is under maintenance, control the accumulator unloading valve to open the pressure relief oil circuit and control the centering solenoid valve to close the centering oil circuit, so that the hydraulic oil in the accumulator flows to the return oil tank of the multi-axle wheel equipment through the pressure relief oil circuit, and the centering cylinder loses its centering power. For details, please refer to... Figure 2 Step S203 of the illustrated embodiment will not be described again here.

[0078] In step S304, if the vehicle is in normal driving condition, the centering solenoid valve is controlled to close the centering oil circuit, and the accumulator unloading valve is controlled to close the pressure relief oil circuit, so that the centering cylinder is in a floating state and loses the centering power.

[0079] Specifically, in this embodiment of the invention, when the steering controller detects a vehicle speed signal greater than zero and less than a preset speed threshold (e.g., less than 30 km / h), the engine is in normal operating condition (not stopped or idling), and no maintenance signal is received, it is determined that the current driving condition is normal. This condition covers various driving modes such as constant speed driving on urban roads, cruising on suburban roads, following other vehicles in congested areas, driving on roads with many curves, driving on slightly bumpy roads, and straight-line acceleration / deceleration. The core requirement is that the rear axle steering and the front axle steering are coordinated and adapted, and the rear axle is not locked in alignment. At this time, the system executes conventional control logic: the accumulator unloading valve 204 remains de-energized, the pressure relief oil circuit is closed, and the accumulator 202 maintains a preset high-pressure holding state to reserve power for emergency switching; the centering solenoid valve 203 is energized and closes the centering oil circuit, cutting off the hydraulic connection between the accumulator 202 and the centering cylinder 201. Since the centering cylinder 201 is not driven by high-pressure hydraulic oil, it is in a floating state, and the piston can move freely. It loses the alignment and locking power to the rear axle. The rear axle can flexibly adapt to different driving modes, such as steering adjustment, road surface undulation, and frequent start-stop, to ensure the vehicle's driving flexibility and smoothness. At the same time, the throttle valve 205 remains in a fixed state and does not participate in oil circuit adjustment, thus avoiding interference with the hydraulic circuit during normal driving.

[0080] Step S305: If the current operating conditions are high-speed driving or parking, the centering solenoid valve is controlled to open the centering oil circuit, and the accumulator unloading valve is controlled to close the pressure relief oil circuit, so that the hydraulic oil in the accumulator flows to the centering cylinder, and the centering cylinder performs centering lock.

[0081] Specifically, in this embodiment of the invention, when the steering controller detects that the vehicle speed has reached a high-speed threshold (e.g., greater than or equal to 30 km / h), the engine is running normally, and there is no maintenance signal input, it determines that the current driving condition is high-speed. At this time, the system activates the centering lock-up control logic, the accumulator unloading valve 204 is continuously de-energized, and the pressure relief oil circuit remains closed to ensure the high-pressure state of the accumulator 202 is stable; the centering solenoid valve 203 is de-energized, opening the centering oil circuit, and the high-pressure hydraulic oil in the accumulator 202 is quickly transported along the centering oil circuit to the designated working chamber of the centering cylinder 201, forming a stable driving force. The hydraulic oil pushes the piston of the centering cylinder 201 to move, driving the rear axle to move towards the preset centering position and complete the lock-up, avoiding rear axle deviation due to road bumps, crosswinds, and other factors during high-speed driving, significantly improving vehicle driving stability and handling precision. During this process, the throttle valve 205 does not intervene and only serves as a redundant component of the oil circuit, maintaining its initial state to ensure rapid response and reliability of the centering lock-up action.

[0082] In some optional implementations, when the steering controller detects a zero vehicle speed signal, an engine that is stopped or idling, and no maintenance signal is received, it determines that the current operating condition is a normal parking condition. The system executes the parking centering lock logic. The accumulator unloading valve 204 is de-energized and closes the pressure relief oil circuit, while the accumulator 202 maintains high pressure. The centering solenoid valve 203 is de-energized and opens the alignment oil circuit. The high-pressure hydraulic oil in the accumulator 202 flows into the centering cylinder 201, driving it to lock the rear axle centering, fixing the rear axle position, and preventing the rear axle from shifting due to external forces (such as pushing or road tilt) during vehicle parking, facilitating quick adaptation to driving conditions after the next start. The throttle valve 205 remains in its default state and does not participate in oil circuit control. At the same time, the other valves maintain their predetermined working states to avoid interfering with the locking action and ensure the stability of the rear axle position in the parking state. If the maintenance signal is not triggered, this operating condition will continue until the vehicle is restarted or a maintenance signal is detected and the system switches to maintenance operating condition.

[0083] In summary, the control logic of the centering solenoid valve 203 and the accumulator unloading valve 204 under different operating conditions is shown in the table below:

[0084] The electro-hydraulic steering system 20 of this invention achieves multi-objective coordination of flexible driving, high-speed stability, reliable parking, and safe maintenance by precisely controlling the on / off state of the centering solenoid valve 203 and the accumulator unloading valve 204 under different operating conditions, taking into account both the control requirements and safety assurance in different scenarios: Under normal driving conditions, the centering solenoid valve is energized to close the alignment oil circuit, and the accumulator unloading valve is de-energized to close the pressure relief oil circuit, so that the centering cylinder is in a floating state, which not only ensures the flexibility and smoothness of rear axle steering, but also maintains the high-pressure reserve of the accumulator, reserving power for rapid switching of operating conditions; under high-speed driving and parking conditions, the centering solenoid valve is de-energized to open By de-energizing the alignment oil circuit and accumulator unloading valve to keep the pressure relief oil circuit closed, the high-pressure oil from the accumulator quickly drives the alignment cylinder to lock the rear axle in center. This effectively avoids the control risks caused by rear axle misalignment during high-speed driving, and also prevents axle displacement caused by external forces during parking, improving vehicle driving stability and parking safety. In maintenance conditions, energizing the alignment solenoid valve closes the alignment oil circuit, while energizing the accumulator unloading valve opens the pressure relief oil circuit. This cuts off the power source of the alignment cylinder at the source and achieves complete pressure relief of the accumulator, allowing the rear axle to maintain a stable maintenance deflection angle. This completely eliminates the risk of squeezing and collision to maintenance personnel when the axle returns to center, ensuring the safety and convenience of maintenance operations.

[0085] The alignment control method provided by this invention adds an accumulator unloading valve to the electro-hydraulic steering system. Based on the operating data of the multi-axle wheel equipment, the current operating condition is determined. If the current condition is maintenance, the accumulator unloading valve is actively controlled to open the pressure relief oil circuit, so that the hydraulic oil in the accumulator flows to the return oil tank of the multi-axle wheel equipment through the pressure relief oil circuit, completely eliminating the high-pressure driving force of the accumulator. Thus, under maintenance conditions, the alignment cylinder loses the alignment power, avoiding the rear axle from automatically returning to center during maintenance. This fundamentally prevents squeezing and collision injuries to maintenance personnel near the axle during the centering process, improving the safety and reliability of maintenance operations.

[0086] This embodiment also provides an alignment control device for implementing the above embodiments and preferred embodiments; details already described will not be repeated. As used below, the term "module" can refer to a combination of software and / or hardware that performs a predetermined function. Although the devices described in the following embodiments are preferably implemented in software, hardware implementations, or a combination of software and hardware, are also possible and contemplated.

[0087] This embodiment provides an alignment control device, such as... Figure 4 As shown, it includes: The data acquisition module 401 is used to acquire the operating data of the multi-axle wheeled equipment.

[0088] The operating condition determination module 402 is used to determine the current operating condition of the multi-axle wheeled equipment based on the operating data. The operating condition includes at least the maintenance condition.

[0089] The pressure relief control module 403 is used to control the accumulator unloading valve to open the pressure relief oil circuit and control the centering solenoid valve to close the centering oil circuit if the current maintenance condition is in progress, so that the hydraulic oil in the accumulator flows to the return oil tank of the multi-axle wheel equipment through the pressure relief oil circuit, and the centering cylinder loses the centering power.

[0090] In some alternative embodiments, the device further includes a steering control module, which, if in normal driving conditions, controls the centering solenoid valve to close the centering oil circuit and controls the accumulator unloading valve to close the pressure relief oil circuit, so that the centering cylinder is in a floating state and loses the centering power.

[0091] In some alternative embodiments, the device further includes: an alignment control module, which controls the alignment solenoid valve to open the alignment oil circuit and controls the accumulator unloading valve to close the pressure relief oil circuit if the current driving condition is high speed or parking condition, so that the hydraulic oil in the accumulator flows to the alignment cylinder and the alignment cylinder performs alignment lock.

[0092] In some optional implementations, the operating data includes at least: vehicle speed signal, engine speed signal, and maintenance signal; the operating condition determination module 402 includes: The data integration and judgment unit is used to determine the current operating condition of the multi-axle wheeled equipment based on vehicle speed signal, engine speed signal and maintenance signal.

[0093] The first operating condition determination unit is used to determine that the current driving condition is normal if the vehicle speed signal is not zero and is lower than a preset speed threshold and the engine is running.

[0094] The second operating condition determination unit is used to determine that the current operating condition is high-speed if the vehicle speed signal is higher than a preset speed threshold and the engine is running.

[0095] The third operating condition determination unit is used to determine that the vehicle is currently in a parking condition if the vehicle speed signal is zero, the engine is stopped or idling, and no maintenance signal is detected.

[0096] The fourth operating condition determination unit is used to determine that the vehicle is currently in a maintenance condition if the vehicle speed signal is zero, the engine is stopped or idling, and a maintenance signal is detected.

[0097] The alignment control device provided in this embodiment of the invention can execute the alignment control method provided in any embodiment of the invention, and has the corresponding functional modules and beneficial effects for executing the method. Further functional descriptions of the various modules and units described above are the same as in the corresponding embodiments described above, and will not be repeated here.

[0098] Figure 5 This is a schematic diagram of a steering controller provided in an embodiment of the present invention.

[0099] The following is a detailed reference. Figure 5 The diagram illustrates a structural schematic suitable for implementing a steering controller according to an embodiment of the present invention. The steering controller may include a processor (e.g., a central processing unit, graphics processor, etc.) 501, which can perform various appropriate actions and processes according to a program stored in read-only memory (ROM) 502 or a program loaded from memory 508 into random access memory (RAM) 503. The RAM 503 also stores various programs and data required for the operation of the steering controller. The processor 501, ROM 502, and RAM 503 are interconnected via a bus 504. An input / output (I / O) interface 505 is also connected to the bus 504.

[0100] Typically, the following devices can be connected to I / O interface 505: input devices 506 including, for example, a touchscreen, touchpad, keyboard, mouse, camera, microphone, accelerometer, gyroscope, etc.; output devices 507 including, for example, a liquid crystal display (LCD), speaker, vibrator, etc.; memory devices 508 including, for example, magnetic tape, hard disk, etc.; and communication devices 509. Communication device 509 allows the steering controller to communicate wirelessly or wiredly with other devices to exchange data. Although Figure 5 A steering controller with various devices is shown, but it should be understood that it is not required to implement or have all of the devices shown, and more or fewer devices may be implemented instead.

[0101] In particular, according to embodiments of the present invention, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, embodiments of the present invention include a computer program product comprising a computer program carried on a non-transitory computer-readable medium, the computer program containing program code for performing the methods shown in the flowcharts. In such embodiments, the computer program can be downloaded and installed from a network via a communication device 509, or installed from a memory 508, or installed from a ROM 502. When the computer program is executed by the processor 501, it performs the functions defined in the alignment control method of the embodiments of the present invention.

[0102] Figure 5 The steering controller shown is merely an example and should not be construed as limiting the functionality and scope of use of the embodiments of the present invention.

[0103] This invention also provides a computer-readable storage medium. The methods described above according to embodiments of the invention can be implemented in hardware or firmware, or implemented as computer code that can be recorded on a storage medium, or implemented as computer code downloaded via a network and originally stored on a remote storage medium or a non-transitory machine-readable storage medium and then stored on a local storage medium. Thus, the methods described herein can be processed by software stored on a storage medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware. The storage medium can be a magnetic disk, optical disk, read-only memory, random access memory, flash memory, hard disk, or solid-state drive, etc.; further, the storage medium can also include combinations of the above types of memory. It is understood that computers, processors, microprocessor controllers, or programmable hardware include storage components capable of storing or receiving software or computer code. When the software or computer code is accessed and executed by the computer, processor, or hardware, the positive control method shown in the above embodiments is implemented.

[0104] A portion of this invention can be applied as a computer program product, such as computer program instructions, which, when executed by a computer, can invoke or provide the methods and / or technical solutions according to the invention through the operation of the computer. Those skilled in the art will understand that the forms in which computer program instructions exist in a computer-readable medium include, but are not limited to, source files, executable files, installation package files, etc. Correspondingly, the ways in which computer program instructions are executed by a computer include, but are not limited to: the computer directly executing the instructions, or the computer compiling the instructions and then executing the corresponding compiled program, or the computer reading and executing the instructions, or the computer reading and installing the instructions and then executing the corresponding installed program. Here, the computer-readable medium can be any available computer-readable storage medium or communication medium accessible to a computer.

[0105] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A positive control method applied to a multi-axle wheeled vehicle, the multi-axle wheeled vehicle including an electro-hydraulic steering system, the electro-hydraulic steering system comprising: The system comprises a centering cylinder, an accumulator, and a centering solenoid valve, characterized in that the electro-hydraulic steering system further includes an accumulator unloading valve, and the method includes: Acquire operational data of multi-axle wheeled equipment; The current operating condition of the multi-axle wheeled equipment is determined based on the operating data, and the operating condition includes at least the maintenance condition; If the current maintenance condition is as described, the accumulator unloading valve is controlled to open the pressure relief oil circuit, and the centering solenoid valve is controlled to close the centering oil circuit, so that the hydraulic oil in the accumulator flows to the return oil tank of the multi-axle wheel equipment through the pressure relief oil circuit, and the centering cylinder loses the centering power.

2. The method according to claim 1, characterized in that, The operating conditions also include: normal driving conditions, and the method further includes: If the vehicle is in the normal driving condition, the centering solenoid valve is controlled to close the centering oil circuit, and the accumulator unloading valve is controlled to close the pressure relief oil circuit, so that the centering cylinder is in a floating state and loses the centering power.

3. The method according to claim 2, characterized in that, The operating conditions also include: high-speed driving conditions and parking conditions, and the method further includes: If the current operating conditions are either high-speed driving or parking, the centering solenoid valve is controlled to open the centering oil circuit, and the accumulator unloading valve is controlled to close the pressure relief oil circuit, so that the hydraulic oil in the accumulator flows to the centering cylinder, and the centering cylinder performs centering lock.

4. The method according to any one of claims 1 to 3, characterized in that, The operational data includes at least: vehicle speed signal, engine speed signal, and maintenance signal; determining the current operating condition of the multi-axle wheeled equipment based on the operational data includes: The current operating condition of the multi-axle wheeled equipment is determined based on the vehicle speed signal, the engine speed signal, and the maintenance signal. If the vehicle speed signal is not zero and is lower than the preset speed threshold, and the engine is running, then it is determined that the current driving condition is normal. If the vehicle speed signal is higher than the preset speed threshold and the engine is running, then it is determined that the current driving condition is high speed. If the vehicle speed signal is zero, the engine is stopped or idling, and no maintenance signal is detected, then it is determined that the vehicle is currently in a parking state. If the vehicle speed signal is zero, the engine is stopped or idling, and the maintenance signal is detected, then it is determined that the vehicle is currently in maintenance condition.

5. An electro-hydraulic steering system, comprising: The hydraulic and electrical control components are characterized in that the hydraulic component includes: a centering cylinder, an accumulator, a centering solenoid valve, and an accumulator unloading valve; the accumulator is connected to the centering solenoid valve; the centering solenoid valve is connected to one end of the centering cylinder via a centering inlet oil line; the other end of the centering cylinder is connected to the centering solenoid valve via a centering return oil line; the centering solenoid valve is connected to the return oil tank of the multi-axle wheeled equipment; one end of the accumulator unloading valve is connected to the accumulator; and the other end of the accumulator unloading valve is connected to the return oil tank via an unloading return oil line. The electronic control unit includes a steering controller, which is electrically connected to the centering solenoid valve and the accumulator unloading valve, and is used to execute the alignment control method according to any one of claims 1 to 4.

6. The electro-hydraulic steering system according to claim 5, characterized in that, The hydraulic system also includes a throttle valve, which is connected in series in the unloading return oil line between the accumulator and the accumulator unloading valve.

7. The electro-hydraulic steering system according to claim 6, characterized in that, The hydraulic system also includes: a steering hydraulic pump, a steering cylinder, a steering axle, and a steering proportioning solenoid valve; The steering controller is electrically connected to the steering ratio solenoid valve; The steering hydraulic pump is connected to the steering proportional solenoid valve, the steering proportional solenoid valve is connected to the steering cylinder through the main oil inlet line, and the steering cylinder is mechanically connected to the steering axle.

8. The electro-hydraulic steering system according to claim 7, characterized in that, The electronic control unit also includes: a steering angle sensor and a pressure sensor, and the steering controller is connected to the steering angle sensor and the pressure sensor respectively; The steering angle sensor is installed on the steering axle and is used to collect the steering angle of the steering axle; The pressure sensor is installed in the outlet oil circuit of the accumulator to collect the pressure value of the accumulator.

9. A steering system, characterized in that, include: The hydraulic steering system and the electro-hydraulic steering system according to any one of claims 5 to 8, wherein the hydraulic steering system is applied to the front axle steering control of a multi-axle wheeled device, and the electro-hydraulic steering system is applied to the rear axle steering control of a multi-axle wheeled device.

10. A multi-axle wheeled device, characterized in that, Includes the steering system as described in claim 9.

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