Hydraulic based bulldozer automatic control and guidance method and apparatus

Abstract

The embodiment of the application discloses a hydraulic-based bulldozer automatic control and guiding method and device. The method comprises the following steps: generating a guiding corridor according to construction design data; generating a corridor deviation state according to vehicle body positioning attitude data, shovel bit positioning data and the guiding corridor; mapping a line deviation into a walking hydraulic control instruction and mapping a working face deviation into a working device hydraulic control instruction according to the corridor deviation state; when a total demand flow corresponding to the instruction exceeds a pump source available flow or the pressure of a full hydraulic system reaches a preset pressure boundary, correcting the walking hydraulic control instruction and the working device hydraulic control instruction; and controlling a walking hydraulic system of the full hydraulic bulldozer based on the corrected walking hydraulic control instruction and controlling a working device hydraulic system of the full hydraulic bulldozer based on the corrected working device hydraulic control instruction.

Description

Technical Field

[0001] This invention relates to the field of construction technology, and in particular to a hydraulic-based automatic control and guidance method and device for bulldozers. Background Technology

[0002] The fully hydraulic bulldozer uses a hydrostatic transmission system consisting of a variable pump and a variable motor, which has the advantages of stepless speed change and flexible operation, and is widely used in earthwork construction.

[0003] Existing bulldozer guidance systems use BeiDou positioning and tilt sensors to detect the blade position and attitude, displaying elevation errors to the operator on a screen to achieve pileless construction guidance. However, this solution is essentially still an open-loop visual guidance system. The system only provides deviation information, and the final decision relies on the operator's manual judgment, failing to form a closed-loop automatic control from deviation perception to hydraulic execution.

[0004] In terms of bulldozer path tracking control, existing solutions obtain the target route by analyzing the construction task, calculate the heading angle deviation, and then generate the driving speed and steering value to achieve automatic tracking.

[0005] Regarding the management of the full hydraulic system, existing solutions achieve constant speed control by detecting the speed difference between the engine and motor, and adjusting the current of the variable pump and the motor's electro-proportional valve through calculation. However, the power distribution of each circuit in the traveling, steering, and working devices is isolated, lacking comprehensive flow scheduling based on real-time operating conditions. Known accumulator energy recovery schemes have also not yet been linked to the real-time power requirements of the traveling and working systems. Summary of the Invention

[0006] In view of this, embodiments of the present invention provide a hydraulically based method and apparatus for automatic control and guidance of bulldozers. The technical solution of the present invention is implemented as follows: A first aspect provides a hydraulic-based automatic control and guidance method for bulldozers, comprising: generating a guidance corridor based on construction design data; the guidance corridor including a center zone corresponding to the target construction route, a boundary protection zone corresponding to the construction boundary, and a working face control zone corresponding to the target working face; generating a corridor deviation state based on the bulldozer's vehicle body positioning posture data, the bulldozer's blade posture data, and the guidance corridor; the corridor deviation state including at least one of the following: the line deviation of the vehicle body relative to the center zone, the working face deviation of the blade cutting edge relative to the working face control zone, the boundary distance of the vehicle body or blade relative to the boundary protection zone, and the full hydraulic system's response to the line deviation and the working face deviation. The hydraulic actuation margin is determined; based on the corridor deviation state, the line deviation is mapped to a travel hydraulic control command, and the working surface deviation is mapped to a working device hydraulic control command; when the total demand flow corresponding to the travel hydraulic control command and the working device hydraulic control command exceeds the pump source's available flow or the pressure of the full hydraulic system reaches a preset pressure boundary, the travel hydraulic control command and the working device hydraulic control command are corrected based on the boundary distance, the line deviation, the working surface deviation, and the hydraulic actuation margin; the travel hydraulic system of the full hydraulic bulldozer is controlled based on the corrected travel hydraulic control command, and the working device hydraulic system of the full hydraulic bulldozer is controlled based on the corrected working device hydraulic control command.

[0007] The second aspect provides a hydraulic-based automatic control and guidance device for bulldozers, comprising: a first generation module for generating a guide corridor based on construction design data; the guide corridor includes a center zone corresponding to the target construction route, a boundary protection zone corresponding to the construction boundary, and a working face control zone corresponding to the target working face; a second generation module for generating a corridor deviation state based on the bulldozer's vehicle body positioning posture data, the bulldozer's blade posture data, and the guide corridor; the corridor deviation state includes at least one of the following: the line deviation of the vehicle body relative to the center zone, the working face deviation of the blade cutting edge relative to the working face control zone, the boundary distance of the vehicle body or blade relative to the boundary protection zone, and the hydraulic pressure of the full hydraulic system for the line deviation and the working face deviation. The system includes: an execution margin; a mapping module, used to map the line deviation to a travel hydraulic control command and the working face deviation to a working device hydraulic control command based on the corridor deviation state; a correction module, used to correct the travel hydraulic control command and the working device hydraulic control command based on the boundary distance, the line deviation, the working face deviation, and the hydraulic execution margin when the total demand flow corresponding to the travel hydraulic control command and the working device hydraulic control command exceeds the pump source's available flow or the pressure of the full hydraulic system reaches a preset pressure boundary; and a control module, used to control the travel hydraulic system of the full hydraulic bulldozer based on the corrected travel hydraulic control command and the working device hydraulic system of the full hydraulic bulldozer based on the corrected working device hydraulic control command.

[0008] The third aspect provides a computer-readable storage medium storing computer-executable instructions; after being executed by a processor, the computer-executable instructions are able to implement the method provided by any of the technical solutions of the first aspect.

[0009] The technical solutions provided in this disclosure have the following technical effects: First, by converting construction design data into a guide corridor, and directly mapping the deviations of vehicle positioning posture, blade posture, and / or guide corridor into walking hydraulic control commands and working device hydraulic control commands, the BeiDou positioning guidance information is upgraded from being used only for display to becoming a closed-loop control input for hydraulic actuators. Deviation correction can be completed without manual intervention, significantly improving construction accuracy and automation level.

[0010] Secondly, the line deviation is mapped to the travel hydraulic control command, and the working surface deviation is mapped to the working device hydraulic control command. The two are then linked within the same control framework through the corridor deviation status. When the blade posture is disturbed due to steering or speed change, the working device control command can automatically respond and compensate, avoiding the problem of decreased surface flatness caused by the independent control of travel and operation.

[0011] Furthermore, when the total demand flow exceeds the pump source's available flow or the system pressure approaches the preset boundary, this invention dynamically corrects the walking hydraulic control command and the working device hydraulic control command based on one or more of the boundary distance, line deviation, working surface deviation, and hydraulic execution margin. Under limited hydraulic power, it prioritizes the protection of loops with larger deviations or insufficient execution margins, thus solving the problem of system overload or insufficient response to critical actions caused by the lack of an arbitration mechanism when multiple loops compete for hydraulic power in existing solutions.

[0012] Then, through the automatic generation of the guide corridor and the automatic correction of deviations, the operator does not need to rely on experience to judge the position of the shovel and the travel trajectory. The system automatically completes the correction and operation adjustment, shortens the operator training cycle, and ensures the consistency of construction quality between different operators and different work shifts. Attached Figure Description

[0013] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings: Figure 1 A flowchart illustrating an automatic control and guidance method for a hydraulically based bulldozer, provided as an embodiment of the present invention; Figure 2 A schematic diagram of a bulldozer provided for an embodiment of the present invention; Figure 3 A schematic diagram of a hydraulic-based automatic control and guidance device for bulldozers provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present invention. Detailed Implementation

[0014] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0015] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "including" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that includes a series of steps or units is not necessarily limited to those explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0016] This invention provides a hydraulic-based automatic control and guidance method for bulldozers, which can be used for autonomous or assisted operations of fully hydraulic bulldozers in scenarios such as road construction and site leveling. Figure 1 This is a flowchart of the steps of an automatic control and guidance method for a hydraulic bulldozer provided in an embodiment of the present invention.

[0017] like Figure 1 As shown, the method may specifically include the following steps: S101, Generate a guide corridor based on construction design data; the guide corridor includes a center zone corresponding to the target construction route, a boundary protection zone corresponding to the construction boundary, and a working face control zone corresponding to the target working face.

[0018] In some embodiments, the construction design data may include information such as the three-dimensional coordinates, curvature, design elevation, cross slope, and / or construction boundary of the target construction route, and the construction design data may be imported into the vehicle controller before operation.

[0019] In some embodiments, construction design data can be imported from a construction management platform, mobile storage device, or remote server before the start of the operation.

[0020] To facilitate unified processing, the controller can convert data from different sources to the construction coordinate system. The construction coordinate system can use a fixed reference point in the construction area as its origin, or it can use the starting point of the target construction route as its origin. The vehicle position can be represented as the coordinates of the vehicle reference point in the construction coordinate system. The blade cutting edge position can be represented as the coordinates of the left, right, and midpoints of the cutting edge in the construction coordinate system.

[0021] Through this step, the controller obtains the basic data needed to generate the guide corridor and execute hydraulic coordination control. The construction design data defines "where it should go" and "what working face should be formed."

[0022] In some embodiments, the guide corridor is a three-dimensional virtual passage area that integrates path constraints, boundary constraints, and work quality constraints. The generation of this corridor is not a simple geometric layout, but rather fully considers the physical characteristics of the bulldozer and the responsiveness of the hydraulic system. For example, the width of the center zone can be dynamically adjusted according to the current vehicle speed and hydraulic response time to ensure a larger allowable lateral deviation for the vehicle body at high speeds, thereby avoiding oscillations in the control system due to frequent corrections. The boundary protection zone is generated by offsetting a safe distance inward from the red line or slope toe line in the construction design drawings to prevent the vehicle body or blade from exceeding the construction boundary. The working face control zone is a control zone generated based on the target design surface (design elevation and cross slope) and includes allowable overcutting and undercutting amounts, generated according to the work mode. For example, a larger undercutting amount is allowed in rough leveling mode to improve work efficiency, while overcutting and undercutting are strictly limited in fine leveling mode to ensure leveling accuracy. By generating the aforementioned guide corridor containing multi-dimensional constraints, abstract construction drawings are transformed into virtual boundaries and targets that the control system can directly use, providing a unified reference benchmark for subsequent deviation calculation and command mapping. The similarities between the coarse leveling mode and the fine leveling mode are: both modes rely on the guide corridor to generate virtual boundary benchmarks for construction control; the differences are: the coarse leveling mode relaxes the undercut threshold to prioritize operational efficiency, while the fine leveling mode strictly controls the overcut and undercut thresholds to ensure ground flatness accuracy.

[0023] For example, the guide corridor can be understood as the operational constraint space established by the controller for the fully hydraulic bulldozer. The centerline zone is used to constrain the vehicle's travel path. The boundary protection zone is used to constrain the vehicle and the blade from the construction boundary or restricted area. The face control zone is used to constrain the elevation and cross slope of the blade cutting edge relative to the target face.

[0024] In some embodiments, the center zone of the track can be extended to both sides from the target construction route. The extension distance does not have to be a fixed value. The controller can determine the allowable lateral deviation based on the current vehicle speed, the curvature of the target construction route, the slope of the target working surface, the blade width, and the hydraulic actuation response time. The allowable lateral deviation can be reduced when the vehicle speed is higher, the curvature is greater, or the hydraulic actuation response time is longer. This can suppress lateral deviation in the turning section in advance.

[0025] In some embodiments, the boundary protection zone can be obtained by offsetting the construction boundary towards the inside of the construction area. The offset distance can be determined based on the vehicle's external dimensions, blade width, current vehicle speed, and braking response time. For bulldozers with a blade width greater than the vehicle's width, the boundary protection zone can simultaneously consider the vehicle's external dimensions and the positions of both ends of the blade. This avoids judging safety solely based on the vehicle's position while ignoring blade end crossing the boundary.

[0026] In some embodiments, the working face control zone can be obtained by extending the target working face upwards and downwards. The downward extension amount can be used as the allowable overcut amount, and the upward extension amount can be used as the allowable undercut amount. In rough leveling operations, the allowable overcut amount and allowable undercut amount can be taken to a wider range. In fine leveling operations, the allowable overcut amount and allowable undercut amount can be taken to a narrower range. For slope operations, the working face control zone may also include the target cross slope and the elevation difference constraint between the left and right ends.

[0027] Through this step, the target construction route, target working face, and construction boundary are no longer three separate sets of data, but are organized into a single guiding corridor. Subsequent control no longer needs to separately inquire about "whether the route deviation exceeds the limit," "whether the elevation deviation exceeds the limit," or "whether the boundary is dangerous," but can make a comprehensive judgment within the same corridor coordinate framework.

[0028] S102, based on the bulldozer's body positioning posture data, the bulldozer's blade posture data, and the guide corridor, a corridor deviation state is generated; the corridor deviation state includes at least one of the following: the line deviation of the vehicle body relative to the center zone of the line, the working surface deviation of the blade cutting edge relative to the working surface control zone, the boundary distance of the vehicle body or blade relative to the boundary protection zone, and the hydraulic actuation margin of the full hydraulic system for the line deviation and the working surface deviation.

[0029] For example, Figure 2 The diagram shown is of a bulldozer. Figure 2 The display includes a blade, an onboard controller (also referred to as the controller), and attitude sensors. The attitude sensors here may include, but are not limited to, at least one of the following: vehicle positioning attitude data and blade pose data.

[0030] In some embodiments, vehicle positioning attitude data can be acquired in real time via an onboard BeiDou RTK positioning module and an inertial measurement unit (IMU) to determine the bulldozer's precise position and heading, pitch, and / or roll angles in the construction coordinate system. In some embodiments, the vehicle positioning attitude data can be collected according to a first sampling period, for example, 20ms to 100ms. Blade pose data and full hydraulic system status data can be collected according to a second sampling period, for example, 5ms to 50ms. The first and second sampling periods can be the same or different.

[0031] In some embodiments, the blade's position and orientation data can be acquired using displacement and angle sensors mounted on the blade lifting cylinder and tilting cylinder to determine the three-dimensional position and orientation of the blade's cutting edge relative to the vehicle body. The full hydraulic system status data may include engine speed, variable pump displacement, system pressure, valve opening degree of each actuator, and hydraulic oil temperature, etc. This data is read in real-time from the engine ECU and various hydraulic sensors via the CAN bus. Acquiring this multi-dimensional data provides a complete data foundation for subsequent precise control and guidance.

[0032] In some embodiments, the vehicle positioning attitude data and the blade pose data define "where it is now" and "where the blade is." The full hydraulic system status data defines "how quickly and at what pressure the correction can be completed." After these data are combined, subsequent steps can determine the line deviation, working surface deviation, and hydraulic actuation margin within the same control cycle.

[0033] In some embodiments, the controller may include a processor, a memory, an input / output interface, and a hydraulic valve drive interface. The memory may store construction design data, guide corridor data, vehicle geometry parameters, hydraulic actuator parameters, and control programs. The processor may execute the automatic control and guidance methods described in this application embodiment. The hydraulic valve drive interface may output proportional valve opening commands, variable pump displacement commands, and travel motor displacement commands. Design task input data, positioning and attitude data, blade pose data, and hydraulic status data can enter the controller within the same control cycle, facilitating the unified generation of line deviation, working surface deviation, and hydraulic actuation margin.

[0034] In some embodiments, the state data of the full hydraulic system can form a hydraulic state vector H. The hydraulic state vector H may include engine speed ne, current displacement of the working pump Dp, current displacement of the travel motor Dm, pump outlet pressure Pp, hydraulic oil temperature Toil, steering actuator load pressure Ps, blade lift actuator load pressure Plift, and blade tilt actuator load pressure Ptilt. The controller can use H to estimate the available flow rate of the pump source and the pressure proximity of each actuator.

[0035] In some embodiments, after acquiring real-time pose data and the guide corridor, the controller calculates a series of key deviation states. These include: line deviation to measure whether the vehicle body is veering off course; working face deviation to measure whether the blade cutting edge has reached the designed elevation and slope; and boundary distance to determine whether the current equipment is approaching the construction boundary. Specifically, this invention also introduces the parameter of hydraulic actuation margin. This hydraulic actuation margin refers to how much flow or pressure remains available after the current hydraulic system has met the requirements for line correction and working face correction. For example, when the system determines that the current pump's flow output is close to its upper limit and the bulldozer is performing heavy-duty digging, the hydraulic actuation margin will be very small. By constructing the above-mentioned multi-dimensional corridor deviation states, the control system can comprehensively perceive the overall state of the bulldozer in terms of position, attitude, work quality, and energy supply, providing a basis for subsequent refined control.

[0036] In some embodiments, the corridor deviation status may include at least one of the following: track deviation, working surface deviation, boundary distance, and hydraulic actuation margin. Track deviation may include lateral deviation and heading deviation. Lateral deviation may represent the lateral distance from the vehicle reference point to the centerline of the track center zone. Heading deviation may represent the angle between the vehicle heading and the tangential direction of the target construction route.

[0037] Working surface deviations can include blade elevation deviation and blade lateral tilt angle deviation. Blade elevation deviation represents the elevation difference between the midpoint of the blade cutting edge and the target working surface. Blade lateral tilt angle deviation represents the difference between the actual elevation difference between the left and right endpoints of the blade cutting edge and the corresponding elevation difference of the target cross slope.

[0038] Boundary distances can include vehicle body boundary distance and blade boundary distance. Vehicle body boundary distance represents the distance from the outer edge of the vehicle body to the inner boundary of the boundary protection zone. Blade boundary distance represents the distance from either the left or right end point of the blade to the inner boundary of the boundary protection zone. The controller can choose the smaller of the two values ​​as the current boundary distance, or it can retain both for subsequent control.

[0039] Hydraulic actuation margin can be determined based on the available flow rate of the pump source, system pressure boundaries, actuator load pressure, and valve opening. For example, the controller can estimate the available flow rate of the pump source, Qavail, and calculate the total required flow rate, Qreq. A higher hydraulic actuation margin is achieved when the difference between Qavail and Qreq is large. A lower hydraulic actuation margin is achieved when Qavail is less than Qreq or when the system pressure reaches a preset pressure boundary.

[0040] Through this step, the controller unifies the vehicle position, blade position, and hydraulic status into a channel deviation state. This state is not simply a navigation error, nor simply a blade elevation error, but rather an intermediate state that simultaneously describes operational geometry deviation and hydraulic actuation capability. This intermediate state can be used in conjunction with subsequent travel control and blade control.

[0041] In some embodiments, as an optional implementation, the hydraulic actuation margin is not the static difference between the pump source's available flow rate and the total required flow rate, but rather: the remaining adjustable flow rate after the minimum flow rate required to maintain the convergence of each deviation component at a preset convergence rate is met under the current channel deviation state. Specifically, the controller establishes a Jacobian mapping relationship J=∂E / ∂Q between the channel deviation state vector E and the hydraulic actuator flow vector Q. This Jacobian matrix is ​​obtained offline through the bulldozer kinematic model and the hydraulic actuator flow-velocity characteristics. Furthermore, the hydraulic actuation margin vector ΔH is expressed as: ΔH=Qavail-Qbase-J + (dE / dt)_target; where Qbase is the base leak compensation flow required to maintain the current actuator position, J + is the pseudo-inverse of the Jacobian matrix, and (dE / dt)_target is the corridor deviation target convergence rate vector determined based on the current road segment status. When any component of ΔH is negative, it indicates insufficient hydraulic actuation margin in that direction, and the controller triggers the correction process in advance. Qavail is the available flow rate of the bulldozer pump source.

[0042] For example, when the boundary distance db decreases sharply while the pump source's available flow rate has not yet exceeded the limit, but the target flow rate J required to maintain db convergence is... + When (dE / dt)_target is close to Qavail, ΔH becomes negative. Based on this, the controller increases the flow weight of the steering actuator in the travel hydraulic control command and limits the blade pressing speed before the total demand flow exceeds the limit. This transforms the flow correction from a passive over-limit response to an active pre-correction based on control feasibility.

[0043] In some cases, the travel hydraulic system and the working device hydraulic system of a fully hydraulic bulldozer are two physically independent hydraulic circuits, but they are deeply coupled at the power source and control decision level, thus forming a unified and controlled fully hydraulic system across the entire vehicle.

[0044] Specifically, the travel hydraulic system adopts a closed-loop hydrostatic transmission circuit, including a travel variable pump driven by the engine and travel variable motors that drive the left and right tracks respectively. A closed hydraulic oil circulation is formed between the travel variable pump and the travel variable motors, and leaked oil is replenished by a replenishment pump. The working device hydraulic system adopts an open-loop circuit, including a working pump driven by another power take-off port of the same engine, and a valve group that controls the blade lifting cylinder, blade tilting cylinder, and ripper cylinder respectively through a multi-way valve. Hydraulic oil enters the actuators from the oil tank through the working pump and the multi-way valve and then returns to the oil tank. Since both the travel variable pump and the working pump are driven by the same engine, the engine output power is the upper limit of the total power of the two hydraulic systems. At the same time, the maximum working pressure of the travel closed loop and the overflow pressure of the working open loop constitute the pressure boundaries of their respective subsystems. Therefore, although the hydraulic oils of the two hydraulic systems do not directly mix, they constitute a unified full hydraulic system at the level of engine power distribution and vehicle control commands.

[0045] Therefore, the hydraulic actuation margin mentioned in this embodiment is a unified assessment quantity at the vehicle level, rather than the local margin of the travel hydraulic system or the working device hydraulic system. The controller comprehensively quantifies the available capabilities of the two independent circuits through the vehicle hydraulic state vector, and this hydraulic actuation margin includes at least one of the following: First, the engine power margin is determined based on the ratio of the current engine speed to the rated speed, and the sum of the current power absorbed by the travel variable pump and the current power absorbed by the working pump. When this power margin is lower than a preset threshold, it indicates that the travel hydraulic system and the working device hydraulic system have experienced power competition at the engine level. Second, the travel circuit pressure margin is determined based on the difference between the actual pressure on the high-pressure side of the travel closed circuit and the set pressure of the travel system safety valve. Third, the working circuit pressure margin is determined based on the proximity of the load pressure of the blade lifting actuator and the blade tilting actuator in the working open circuit to their respective overflow pressures. Fourth, the flow coordination margin is determined based on the theoretical output flow of the travel variable pump at the current engine speed and swashplate displacement, the theoretical output flow of the working pump at the current engine speed and displacement, and the difference between these values ​​and the total flow of the travel motor required by the travel hydraulic control command and the total flow of each actuator required by the working device hydraulic control command.

[0046] When the controller determines that any of the above-mentioned margins is insufficient, it triggers a vehicle-level coordinated correction of the travel hydraulic control commands and the working device hydraulic control commands. For example, when the engine power margin is insufficient and the working surface deviation is large, the controller prioritizes ensuring the power demand of the working device hydraulic system by reducing the displacement command of the travel variable pump to reduce the bulldozer speed, thereby transferring the power released by the engine to the working pump to maintain the response speed of the blade lifting and tilting actions. Conversely, when the boundary distance decreases sharply while the working surface deviation is within the allowable range, the controller prioritizes ensuring the power demand of the travel hydraulic system by limiting the blade pressing speed to reduce the load on the working pump, ensuring that the steering actuator receives sufficient engine power and travel pump flow to achieve rapid boundary avoidance.

[0047] It should be further clarified that the "total required flow rate corresponding to the travel hydraulic control command and the working device hydraulic control command exceeds the pump source's available flow rate" mentioned in this embodiment does not refer to the physical flow rate superposition of the travel hydraulic system and the working device hydraulic system sharing the same hydraulic pump. Rather, it refers to the fact that at the vehicle controller level, the equivalent flow rate required by the travel closed loop and the target flow rate of each actuator required by the working open loop are normalized and converted, and then compared with the theoretical total flow rate or equivalent total power that each pump can provide at the current engine speed. When the normalized total demand exceeds the vehicle's pump source capacity, the controller initiates cross-system coordinated correction.

[0048] S103, based on the corridor deviation state, the line deviation is mapped to a travel hydraulic control command, and the working face deviation is mapped to a working device hydraulic control command.

[0049] In some embodiments, the controller generates control commands for the travel system and the working device based on the deviation state generated in S102. Specifically, a PID controller or a model predictive controller (MPC) can be used to map the line deviation and heading deviation into displacement control commands for the left and right travel motors to achieve automatic steering and line-following. Simultaneously, the working surface deviation (elevation deviation and cross slope deviation) is mapped into opening control commands for the blade lifting valve and tilt valve to achieve automatic adjustment of the blade cutting edge posture. In this invention, the above mapping relationship is not fixed but can be dynamically adjusted according to the current road condition. For example, when the fully hydraulic bulldozer is on a straight bulldozing section, control weight is prioritized for the working surface deviation to ensure construction quality; when on a turning section, control weight is prioritized for the line deviation and heading deviation to ensure correct travel trajectory. Through this differentiated mapping strategy, intelligent switching of control focus under different operating conditions is achieved, thereby simultaneously ensuring driving safety, operational accuracy, and construction efficiency.

[0050] In some embodiments, the travel hydraulic control commands may include a target vehicle speed, a target displacement of the left and right travel motors, a steering control amount, or a travel pump displacement control amount. The working device hydraulic control commands may include the opening degree of the blade lifting valve, the opening degree of the blade tilting valve, the opening degree of the ripper valve, the target displacement of the variable pump, and pressure limit parameters.

[0051] The controller can establish a mapping relationship between line deviation and travel hydraulic control commands. For example, when lateral deviation increases, the controller can increase the steering control input. When heading deviation increases, the controller can adjust the displacement difference between the left and right travel motors. When boundary distance decreases, the controller can reduce the target vehicle speed and increase the line correction weight.

[0052] The controller can also establish a mapping relationship between working face deviation and hydraulic control commands of the working device. For example, when the blade elevation is higher than the working face control zone, the controller can increase the opening of the blade lowering valve. When the blade elevation is lower than the working face control zone, the controller can increase the opening of the blade lifting valve. When the blade lateral tilt angle deviation increases, the controller can adjust the opening of the tilt valve to make the two ends of the blade cutting edge tend towards the target lateral slope.

[0053] It's understandable that track deviation and working surface deviation may not be independent. Vehicle steering alters the spatial trajectory of the blade's cutting edge. Blade downward pressure also affects bulldozing resistance and vehicle movement. Therefore, when generating these two types of commands, the controller can retain hydraulic actuation margin as a common constraint. This avoids excessively large motion demands from the travel control and working device control outputs respectively.

[0054] S104, when the total required flow rate corresponding to the travel hydraulic control command and the working device hydraulic control command exceeds the available flow rate of the pump source or the pressure of the full hydraulic system reaches the preset pressure boundary, the travel hydraulic control command and the working device hydraulic control command are corrected according to the boundary distance, the line deviation, the working surface deviation and the hydraulic execution margin.

[0055] In some embodiments, when the system calculates the total required flow rate of all hydraulic actuators based on the control command generated in S103, and finds that the required flow rate exceeds the maximum flow rate that the hydraulic pump can currently provide, or the system pressure is close to the safety valve setting value, the control strategy will switch from "target accuracy priority" to "energy management and safety priority". At this time, the controller will activate a flow / pressure distribution arbitration mechanism. This mechanism does not simply reduce the speed of all actuators proportionally, but intelligently distributes the flow rate according to the current working situation. For example, if the boundary distance is very small, indicating that the bulldozer is working near the boundary, the flow rate supply to the steering system will be prioritized to prevent collisions, while the speed of the blade lifting / lowering will be reduced or suspended. If the hydraulic actuator margin shows that the pump is already working at full load and the working surface deviation is large, the controller will decide to prioritize the flow rate of the blade lifting and lowering according to the current working mode (such as fine leveling mode), while appropriately reducing the bulldozer's travel speed to ensure the final working surface flatness. Through the above comprehensive arbitration and correction based on multiple factors, engine speed drop or system overflow caused by insufficient power is avoided, achieving optimal control output within the system capacity boundary.

[0056] In some embodiments, the controller may first determine whether the total demand flow exceeds the pump source's available flow. The total demand flow can be calculated from the target speed of each actuator and the effective area of ​​the corresponding hydraulic cylinder or the displacement of the hydraulic motor. The pump source's available flow can be determined based on the engine speed, the current displacement of the variable pump, the hydraulic oil temperature, and the pump efficiency status.

[0057] When the total demand flow exceeds the pump's available flow, the controller can stop directly controlling all actuators according to the original instructions. The controller can adjust the control instructions based on boundary distances, line deviations, working surface deviations, and hydraulic actuation margins. For example, when the boundary distance is small, the controller can prioritize flow to the steering actuator and the travel hydraulic system. When the working surface deviation is large and the boundary distance is sufficient, the controller can prioritize flow to the blade lifting actuator and the blade tilting actuator.

[0058] When the pressure in the full hydraulic system reaches a preset pressure boundary, the controller can reduce the target speed or target flow rate of lower-priority actuators. The preset pressure boundary may include the upper limit of pump outlet pressure, the upper limit of actuator operating pressure, the upper limit of return oil pressure, and the upper limit of pressure correction corresponding to hydraulic oil temperature. This reduces the need for prolonged pressure relief via the relief valve.

[0059] In some embodiments, the process of correcting the travel hydraulic control command and the working device hydraulic control command based on boundary distance, line deviation, working surface deviation, and hydraulic actuation margin is constructed as solving a constrained multi-objective optimization problem in each control cycle, namely, minimizing the objective function: J=w1 (ey / eymax)2 +w2 (eψ / eψ_max) 2 +w3 (ez / ezmax) 2 +w4 (eroll / eroll_max) 2 +w5 (dbref / db) 2 +w6 Σ(Pi / Piboundary) 2 ; Constraints: ΣQi≤Qavail, Pi≤Piboundary, i∈{steer,lift,tilt}, Qimin≤Qi≤Qimax|dQi / dt|≤(dQ / dt)_max.

[0060] Where ey, eψ, ez, and eroll represent the lateral deviation of the track, the heading deviation, the blade elevation deviation, and the blade lateral tilt angle deviation, respectively; db is the current boundary distance, and dbref is the safety reference distance; Pi is the load pressure of the i-th actuator, and Piboundary is the preset pressure boundary; Qi is the allocated flow rate of the i-th actuator; w1 to w6 are weighting coefficients dynamically adjusted according to the current road segment status or experimental values ​​predetermined by laboratory experiments related to the current road segment status, for example, increasing w5 in the boundary-adjacent section and increasing w3 and w4 in the fine-level section. steer represents steering, lift represents lifting, and tilt represents tilting.

[0061] The controller directly obtains the optimal flow allocation Qi for each actuator by solving the above quadratic programming problem. The optimal flow allocation is the flow component corresponding to the corrected travel hydraulic control command and the working device hydraulic control command. The reduced flow is not proportionally distributed, but rather transferred from the actuator with the smallest contribution to the objective function J to the actuator with the largest contribution.

[0062] Furthermore, when the optimal flow rate Qsteer for the steering actuator is found in the solution results... If the heading deviation convergence requirement is still not met, the controller will adjust the blade's target cutting depth in the hydraulic control command of the working device. By actively reducing the blade's cutting resistance, the load pressure on the travel motor is indirectly reduced, thereby releasing the pump's available flow to the steering system. This "hydraulic-mechanical" coupled correction mechanism means that flow distribution is no longer limited to flow redistribution at the actuator level, but rather to active adjustment at the working load level.

[0063] S105, based on the modified walking hydraulic control command, control the walking hydraulic system of the fully hydraulic bulldozer, and based on the modified working device hydraulic control command, control the working device hydraulic system of the fully hydraulic bulldozer.

[0064] In some embodiments, the controller sends the final revised hydraulic control commands for travel to the electro-hydraulic proportional valves of the left and right travel motors, driving the motors to rotate at a specific speed to achieve straight-line, steering, and speed control of the bulldozer. Simultaneously, it sends the revised hydraulic control commands for the working device to the electro-hydraulic proportional valves of the blade lifting and tilting cylinders, driving the blade to lift, lower, or tilt to achieve precise trimming of the working face. Ultimately, through the execution of these commands, the fully hydraulic bulldozer can safely, efficiently, and precisely complete automated operations along the guide corridor under various complex working conditions.

[0065] The method provided in this invention systematically and structurally transforms construction requirements into control constraints by introducing a guide corridor comprising a centerline zone, a boundary protection zone, and a working face control zone. Simultaneously, by generating corridor deviation states including line deviation, working face deviation, boundary distance, and hydraulic execution margin, a comprehensive perception of equipment status and operational dynamics is achieved. Furthermore, this method dynamically adjusts the control strategy based on different road segment conditions and system energy states. When system capacity is insufficient, intelligent arbitration and command correction are performed based on boundary distance, deviation, and hydraulic margin, thereby ensuring the safety, operational accuracy, and system stability of the fully hydraulic bulldozer under complex operating conditions. This solves the technical problems of incomplete control systems and inefficient energy management in existing technologies.

[0066] In some embodiments, the travel hydraulic system may include a travel pump, left and right travel motors, and a steering actuator. The working device hydraulic system may include a working pump, a blade lifting actuator, a blade tilting actuator, a ripper actuator, and an electro-hydraulic proportional valve. The controller can output modified commands to the corresponding valve group or pump motor controller.

[0067] Through S101 to S105, the controller can first integrate the construction target, vehicle status, blade status, and hydraulic status into a gallery deviation status, and then use the gallery deviation status to jointly schedule the travel hydraulic system and the working device hydraulic system. This method enables the vehicle line control, blade working face control, and hydraulic flow and pressure constraints to be coordinated within the same control cycle. Therefore, when a fully hydraulic bulldozer enters turning, slope change, boundary proximity, or complex action conditions, it can reduce the competition between control loops and lower the risks of overcutting, missed cutting, boundary crossing, and hydraulic shock.

[0068] This invention provides another specific method for generating a guide corridor. In step S101, generating the guide corridor based on construction design data may specifically include the following sub-steps: The permissible lateral deviation of the center zone of the target construction route is determined based on the curvature of the target construction route, the current vehicle speed, the slope of the target working surface, the blade width, and / or the hydraulic execution response time.

[0069] In some embodiments, the width of the center band is not a fixed value but is designed as a dynamic variable. The controller calculates a forward sight distance based on the current vehicle speed; the higher the speed, the longer the forward sight distance. Within this forward sight distance, the system analyzes the curvature of the target construction route. If a sharp curve is approaching, the controller appropriately widens the permissible lateral deviation of the center band, allowing the vehicle to travel within a slightly wider band to avoid system oscillations or running off the curve due to overcorrection of steering. Simultaneously, blade width and hydraulic actuation response time are also taken into consideration: a wider blade allows for greater lateral offset of the vehicle without affecting the work surface boundary, while a longer hydraulic response time requires a slightly wider center band to allow the system sufficient time for smooth corrections. This dynamic adjustment makes the guide corridor more consistent with the responsiveness of the actual physical system, improving the smoothness and stability of control.

[0070] Based on the operating mode, the target elevation of the target working face, and / or the target cross slope, determine the allowable overcut and undercut of the control zone of the working face.

[0071] In some embodiments, the upper and lower boundaries of the working face control zone (i.e., the maximum and minimum allowable elevations) are dynamically determined based on the currently selected work mode. For example, when the work mode is "rough leveling" or "heavy-load excavation," the system sets a larger allowable undercut (allowing the blade to cut away less soil) and an allowable overcut to maximize work efficiency. When the work mode is "fine leveling" or "fine slope trimming," the system sets both the allowable overcut and undercut to very small values ​​to achieve the highest leveling accuracy. Furthermore, for working faces with cross slope requirements, the elevation boundaries of the control zone on the left and right sides of the blade are different, and the cutting edges at both ends of the blade need to track their respective working face control zones. By directly linking the work mode with the boundaries of the working face control zone, the quantification and automatic control of work quality and efficiency are achieved.

[0072] The guide corridor is generated based on the allowable lateral deviation, the allowable overcut, the allowable undercut, and the construction boundary protection distance.

[0073] In some embodiments, the controller can determine the permissible lateral deviation of the center zone of the road based on the curvature of the target construction route, the current vehicle speed, the slope of the target working surface, the blade width, and the hydraulic actuation response time. Curvature can represent the degree of curvature of the target construction route near the current position. Hydraulic actuation response time can represent the time required for the vehicle's lateral movement to begin to change effectively after the controller issues a steering or travel motor displacement command.

[0074] As an optional implementation, the controller can determine the allowable lateral deviation Wline as follows: Wline=Wbase-k1 v-k2 C-k3 Tresp+k4 Mhyd.

[0075] Where Wbase represents the allowable lateral width of the foundation. v represents the current vehicle speed. C represents the curvature of the target construction route. Tresp represents the hydraulic actuation response time. Mhyd represents the hydraulic actuation margin. k1, k2, k3, and k4 represent calibration coefficients, respectively. The above formula is only one possible implementation. The controller can also determine Wline using lookup tables, piecewise functions, or model prediction methods.

[0076] In some embodiments, when the vehicle speed is in the low-speed fine-leveling range of approximately 0.5 m / s to 1.0 m / s, the center strip can be relatively narrow to ensure track continuity. When the vehicle speed is in the ordinary bulldozing range of approximately 1.0 m / s to 2.0 m / s, the center strip can be of medium width. When the vehicle speed exceeds approximately 2.0 m / s or the road curvature increases, the controller can narrow the center strip in advance and increase the steering pre-adjustment amplitude. The above values ​​are used to illustrate different control levels, and this application does not limit them.

[0077] The controller can determine the allowable overcut and undercut of the control zone on the working face based on the operation mode, the target elevation of the target working face, and / or the target cross slope. Operation modes can include rough leveling mode, semi-fine leveling mode, fine leveling mode, slope operation mode, and transport passage mode. In rough leveling mode, larger overcut and undercut are allowed to ensure efficient earthmoving. In fine leveling mode, the control zone on the working face can be narrowed to reduce final leveling error. Undercut is the difference in elevation between the actual ground elevation after cutting by the shovel and the design target elevation in earthmoving leveling operations; it represents the remaining thickness of the soil layer that has not been cut to the standard elevation. Overcut is the difference in elevation between the actual ground elevation after cutting by the shovel and the design target elevation in earthmoving leveling operations; it represents the depth of excavation beyond the standard elevation.

[0078] For example, in rough leveling mode, the allowable overcut is approximately 30mm to 80mm, and the allowable undercut is approximately 30mm to 100mm. In fine leveling mode, the allowable overcut is approximately 5mm to 20mm, and the allowable undercut is approximately 5mm to 30mm. In slope operation mode, the working face control zone can also be set with a range of elevation differences between the left and right endpoints according to the target cross slope, thus providing clear constraints on the control of the blade's lateral tilt angle.

[0079] The controller can also generate a boundary protection zone based on the construction boundary protection distance. This distance can be determined based on the vehicle width, blade width, positioning error, braking distance, and communication delay. When the positioning error is large or the ground adhesion is poor, the boundary protection distance can be increased. This helps prevent boundary violations caused by both positioning error and braking lag.

[0080] In the above embodiments, the guide corridor is not a fixed-width channel, but a dynamic constraint space related to the route curvature, vehicle speed, gradient, blade width, and hydraulic response capability. Since both the center zone and the working face control zone are corrected based on the hydraulic execution response time or hydraulic execution margin, the controller can tighten the geometric constraints in advance when the hydraulic response is slow, thereby reducing the hysteresis correction amount after the vehicle enters the turning section or the slope change section.

[0081] In some embodiments, the controller integrates the permissible lateral deviation of the center zone of the track, the permissible overcut and undercut of the working face control zone determined in the above steps, and the preset construction boundary safety distance to generate a complete three-dimensional guide corridor. This corridor provides a "soft passage" (center zone of the track) for the vehicle body in the horizontal plane, a "soft passage" (working face control zone) for the blade in the vertical section, and an insurmountable "hard boundary" (boundary protection zone) for the equipment on the outside of the track. The above three-dimensional constraint zones together constitute the complete definition of the guide corridor.

[0082] The guide corridor generation method provided in this invention dynamically determines the center zone, working face control zone, and boundary protection zone of the track, generating a virtual guide space that reflects both construction design requirements and the kinematics and dynamics of the bulldozer itself. This dynamically generated guide corridor provides a more scientific and reasonable benchmark for subsequent deviation state calculations, thereby improving the adaptability and robustness of the entire automatic control system.

[0083] This invention provides another specific control command mapping method. In S103, based on the corridor deviation state, the line deviation is mapped to a travel hydraulic control command, and the working face deviation is mapped to a working device hydraulic control command. Specifically, this may include the following sub-steps: The first variable is determined based on the route deviation, heading deviation, boundary distance, and / or remaining distance of the road segment.

[0084] In some embodiments, the first variable is a set of key indicators characterizing the control requirements of the travel system. Among them, line deviation and heading deviation jointly determine the degree of deviation of the vehicle's current position and direction relative to the target route, forming the basis of line-following control. Boundary distance reflects the degree of closeness between the current equipment and the construction boundary. Remaining distance of the road segment is used to determine the destination of the current control action; for example, at the end of a road segment, the system will prioritize correcting the travel direction to prepare for the next segment. These parameters collectively constitute the input basis for the travel control system to adjust steering and speed.

[0085] The second variable is determined based on the working face deviation, the blade lateral tilt angle deviation, and / or the blade attitude deviation relative to the vehicle body.

[0086] In some embodiments, the second variable is a set of key indicators characterizing the control requirements of the working device. The working face deviation includes the elevation deviation of the left and right ends of the blade, which is the direct basis for controlling the blade's lifting and tilting. The blade's lateral tilt angle deviation refers to the difference between the actual and target lateral slope of the blade. The blade's attitude deviation relative to the vehicle body is used to determine the impact of changes in the vehicle body's attitude on the blade's working state. For example, when the vehicle body pitches up, the blade height needs to be compensated to maintain a constant working face elevation. These parameters collectively constitute the input basis for the working device control system to adjust the blade's height and angle.

[0087] When the boundary distance is greater than the boundary warning distance, the control weight corresponding to the second variable is increased, and the correction amplitude corresponding to the first variable is limited.

[0088] In some embodiments, when the system determines that the current bulldozer is far from the construction boundary (the boundary distance is greater than the warning value) and is within the safe zone, the control strategy will focus on ensuring work quality. In this case, the control weight corresponding to the working face deviation (the second variable) will be increased, enabling the blade to track the target working face more actively and quickly. Simultaneously, the range of vehicle body correction will be limited, allowing the vehicle body a large floating space within the center zone without drastic steering corrections. This "heavy on work, light on navigation" strategy avoids affecting the blade's leveling effect due to frequent turning, and is particularly suitable for large-scale site leveling operations.

[0089] When the boundary distance is less than or equal to the boundary warning distance, the control weight corresponding to the first variable is increased, and the shovel pressing speed or shovel cutting depth is limited.

[0090] In some embodiments, when the system determines that the bulldozer is approaching the construction boundary, the control strategy will quickly switch to a "safety-first" mode. At this time, the control weights corresponding to line deviation and heading deviation (the first variable) will be increased to ensure that the vehicle can quickly correct its heading and move away from the boundary. Simultaneously, to mitigate risks, the downward speed or maximum cutting depth of the blade will be actively limited to prevent the blade from running off the boundary or damaging the slope due to sudden changes in cutting resistance or misoperation when approaching the boundary. This "navigation-focused, operation-light" strategy, by actively sacrificing some operational efficiency for absolute safety, is particularly crucial in operation scenarios near slopes, such as embankment construction and shoulder shaping.

[0091] In some embodiments, the first variable primarily describes the vehicle's movement along the guide corridor. The first variable can be mapped to the travel hydraulic system. For example, increasing the first variable can cause the controller to reduce the target vehicle speed, adjust the displacement difference between the left and right travel motors, or increase the target flow rate of the steering actuator. The second variable primarily describes the state of the blade cutting edge relative to the working face control zone. The second variable can be mapped to the working device hydraulic system. For example, increasing the second variable can cause the controller to adjust the opening of the blade lifting valve or tilting valve. In some embodiments, the controller can set a control weight A1 for the first variable and a control weight A2 for the second variable. A1 and A2 may not be fixed values ​​but dynamically change based on the boundary distance. When the boundary distance is greater than the boundary warning distance, the vehicle is in a relatively safe zone. The controller can increase A2 and limit the correction amplitude corresponding to A1. In this case, the vehicle only performs minor line corrections, and the blade lifting and tilting actions bear the main responsibility for correcting working face errors.

[0092] When the boundary distance is less than or equal to the boundary warning distance, the vehicle or blade is approaching the construction boundary. The controller can increase A1 and limit the blade's downward pressing speed or cutting depth. This prevents the controller from continuing to press the blade down to reduce working face deviation, which would increase bulldozing resistance or cause the vehicle to deviate towards the boundary.

[0093] It is understandable that the first and second variables can also be represented by state vectors. For example, the first variable can be represented as X1=[ey,eψ,db,sr]. Here, ey ​​represents lateral deviation, eψ represents heading deviation, db represents boundary distance, and sr represents remaining distance of the road segment. The second variable can be represented as X2=[ez,eroll,eb]. Here, ez represents blade elevation deviation, eroll represents blade lateral tilt deviation, and eb represents blade attitude deviation relative to the vehicle body. The controller can map X1 and X2 into control commands through lookup tables, linear quadratic control, model predictive control, or rule tables.

[0094] The decomposition of the first and second variables described above allows the controller to allocate vehicle body correction and blade correction to more suitable hydraulic actuators. When the boundary distance is sufficient, the system allocates more hydraulic power to blade control, which helps maintain the continuity of the working face. When the boundary distance is insufficient, the system allocates more hydraulic power to travel correction, which helps avoid boundary overtravel and control failures.

[0095] The control command mapping method provided in this embodiment of the invention introduces boundary distance as a core judgment factor, realizing an adaptive strategy switching of "focusing on work quality when far from the boundary and focusing on safety protection when close to the boundary." This situational awareness-based differentiated control effectively balances the multi-objective conflict between work accuracy, driving safety, and boundary protection in a fully hydraulic bulldozer, improving the equipment's autonomous operation capability in complex environments. This embodiment of the invention also provides another specific control command mapping method aimed at solving the problem of control objective conflict under different road segment conditions. In S103, based on the corridor deviation state, the line deviation is mapped to a travel hydraulic control command, and the working surface deviation is mapped to a working device hydraulic control command. This may include: determining the road segment state where the fully hydraulic bulldozer is located when the correction direction of the deviation causes the same hydraulic actuator to generate opposite adjustment needs; determining the adjustment priority order based on the road segment state; and mapping the working surface deviation to the working device hydraulic control command based on the adjustment priority order.

[0096] For example, if the road segment is a straight bulldozing section, the working face deviation is reduced first; and / or, if the road segment is a boundary adjacent section, the boundary distance is increased first; and / or, if the road segment is a turning section, the heading deviation is reduced first; and / or, if the road segment is a leveling section, the elevation deviation and cross slope deviation of the shovel cutting edge are reduced first.

[0097] In some embodiments, the road segment status of the fully hydraulic bulldozer is determined when the correction direction of the line deviation and the correction direction of the working face deviation cause the same hydraulic actuator to generate opposite adjustment requirements.

[0098] In some embodiments, the control system may encounter conflicting control commands under certain operating conditions. For example, when a bulldozer is turning, the outer travel motor needs to accelerate to follow the line; however, to maintain the level of the blade, the blade tilt cylinder may need to be adjusted. This adjustment may affect the vehicle's tilt, thus affecting steering performance. In this case, two different control objectives (line following and leveling) impose conflicting requirements on the same physical system or coupled system. To resolve this conflict, the system first determines the current road condition to provide a basis for subsequent decisions.

[0099] If the road section is a straight bulldozing section, then the deviation of the working face should be reduced first.

[0100] In some embodiments, when the system identifies that it is currently in a straight bulldozing section, it means that the requirements for the driving trajectory are relatively low, while the requirements for construction quality are high. Therefore, when a control conflict occurs, the system will prioritize ensuring the convergence of the working face deviation, that is, prioritizing the elevation and cross slope accuracy of the blade, while allowing a small lateral deviation of the vehicle body within the center zone that does not affect safety. This strategy ensures the quality of the most important tasks on the straight section, such as the leveling operation.

[0101] If the road segment is a boundary-adjacent segment, then the boundary distance should be increased first.

[0102] In some embodiments, safety becomes the top priority when the system detects that it is approaching the boundary protection zone. At this point, any control commands that could cause the vehicle or blade to move further towards the boundary will be suppressed. For example, when steering correction and blade tilt correction conflict, the system will prioritize steering commands that move the vehicle away from the boundary.

[0103] If the road segment is a curve, then the heading deviation should be reduced first.

[0104] In some embodiments, when the system detects entry into a curve, ensuring accurate alignment of the vehicle becomes the primary objective. At this time, the control system prioritizes allocating hydraulic power to the steering system to ensure that the heading deviation can be quickly corrected to zero. During this process, the blade's working face deviation control can be temporarily deactivated or its response speed reduced to avoid exacerbating vehicle roll or affecting steering flexibility due to excessive blade adjustments during the turn.

[0105] If the road section is in a finely leveled state, then the elevation deviation and cross slope deviation of the shovel cutting edge should be reduced first.

[0106] In some embodiments, when the work enters the finishing stage, the final surface quality becomes the overriding objective. At this point, regardless of the vehicle's movement, the control system will focus all its efforts on minimizing the deviation of the blade's cutting edge from the control zone of the work surface. Even if this means frequent adjustments to the travel speed or minor steering corrections, all system resources will prioritize the precise control of the blade's position.

[0107] The control command mapping method provided in this invention identifies road segment status and establishes a clear control priority arbitration mechanism based on that status. This method effectively resolves potential conflicts between multiple control objectives under specific working conditions, ensuring that the fully hydraulic bulldozer can execute the control strategy most suitable for the current operational needs at any position on the route, thereby improving the intelligence and precision of automatic control.

[0108] The method may also include the following steps: When there are changes in route curvature, changes in target working face slope, narrowing of construction boundary, or switching of operation mode within the current line of sight, a road section buffer zone is generated in the guide corridor; the line of sight is determined based on the current vehicle speed and hydraulic execution response time.

[0109] In some embodiments, the control system not only monitors deviations from the current position but also "looks" ahead at the guide corridor based on a dynamically calculated forward sight distance. This forward sight distance is proportional to vehicle speed and hydraulic system response time. This means that the faster the vehicle speed, the farther the system "sees"; the slower the hydraulic system response, the earlier the system needs to prepare. When a characteristic change occurs in the corridor within the forward sight distance—for example, when the route is about to turn, the slope of the working face is about to change from uphill to downhill, the construction boundary is about to narrow, or the work mode is about to switch—the system automatically generates a "road section buffer" marker a distance before these characteristic change points. This marker is used to notify the control system that the road conditions ahead are about to change.

[0110] Before the fully hydraulic bulldozer enters the buffer zone of the road section, a hydraulic preset command is generated; the hydraulic preset command includes at least two of the following: variable pump displacement preset amount, travel motor displacement transition amount, blade lift valve opening preset amount, and blade tilt valve opening preset amount.

[0111] In some embodiments, when the vehicle body has not yet reached the point of road condition change but has entered its corresponding road section buffer zone, the controller will calculate in advance the optimal hydraulic state required to cope with the change ahead and generate a series of preset commands. For example, if an uphill section is about to begin, the system can preset to increase the displacement of the variable pump to provide greater traction; if a turning section is about to begin, the system can preset to decrease the displacement of the travel motor to decelerate and pre-set the displacement difference between the left and right motors required for the turn; if a leveling section is about to begin, the system can preset to reduce the response speed of the blade lift valve to achieve more precise control. The above preset commands are not executed immediately, but are cached and marked with the trigger time or trigger position.

[0112] Based on the hydraulic preset command, the walking hydraulic system and the working device hydraulic system are preset controlled.

[0113] In some embodiments, the controller synchronously executes the preset commands when the vehicle actually reaches the trigger point corresponding to the preset command. By actually reaching the trigger point corresponding to the preset command, the state of the hydraulic system is changed in advance before the load change occurs. For example, by pre-setting to increase the pump displacement before the blade cuts into hard soil, engine speed drop can be effectively avoided; by pre-setting to adjust the displacement of the left and right motors before entering a curve, smoother steering can be achieved. This feedforward and preset control method can effectively compensate for the response delay of the hydraulic system, changing the timing of control actions from a reactive response to proactive preparation.

[0114] The preset control method provided in this invention proactively identifies future working condition change points and generates road section buffer zones within the guide corridor. Based on this, it generates and executes hydraulic preset commands in advance, effectively overcoming problems such as power matching lag, impact, and oscillation caused by hydraulic system response delays in existing technologies. This method enables fully hydraulic bulldozers to anticipate and prepare in advance, much like a skilled operator, when facing complex terrain and working condition changes, significantly improving the smoothness and efficiency of the operation process.

[0115] This invention provides a more specific preset control method. Based on the hydraulic preset command, preset control is performed on the walking hydraulic system and the working device hydraulic system, which may specifically include the following sub-steps: When the fully hydraulic bulldozer is about to enter a turning section, reduce the target vehicle speed and limit the blade pressing speed, and adjust the displacement difference between the left and right travel motors according to the curvature radius of the turning section.

[0116] In some embodiments, for scenarios approaching a turn, the controller generates a set of coordinated preset instructions. First, a target speed reduction is preset, allowing the bulldozer to enter the curve at a safer and more controllable speed. Second, a limit is preset on the blade's downward pressing speed to prevent additional lateral resistance caused by the blade accidentally cutting into the soil during the turn. Simultaneously, the controller accurately calculates the theoretically required difference in speed between the left and right travel motors based on the radius of curvature of the target route in the guide corridor and presets this into the motor displacement control signal. When the bulldozer enters the curve, the displacement of the left and right motors adjusts synchronously according to the preset values, achieving "preset steering." This ensures that the actual steering trajectory closely matches the target route, avoiding lag and overshoot caused by steering after detecting deviations.

[0117] When the fully hydraulic bulldozer enters the slope change section, the target position of the blade lifting cylinder is adjusted in advance according to the difference between the current vehicle posture and the slope of the target working surface, and the upper limit of the change rate of the blade lifting valve opening is set.

[0118] In some embodiments, for scenarios involving approaching an uphill or downhill slope, the control system pre-calculates the change in the vehicle's pitch angle before and after the slope change. Based on this change, the system can predict the compensating displacement required by the blade lifting cylinder to maintain a constant blade cutting edge elevation and pre-set this as a new target value. Simultaneously, to prevent excessively rapid valve core movement leading to impact, the system sets a smooth upper limit on the opening rate of the blade lifting valve. Thus, when the bulldozer actually enters the slope, the blade can adjust "smoothly" with the change in the vehicle's posture, ensuring a smooth and continuous transition of the working face.

[0119] When the fully hydraulic bulldozer is about to leave the turning section or the slope change section, the target control value of the blade corresponding to the working face control zone is restored in advance.

[0120] In some embodiments, when the bulldozer is about to pass a road condition change point, the control system will restore the control target of the blade from the "transitional adjustment state" to the "normal working surface tracking state" in advance. For example, when about to exit a curve, the system will release the limitation on the downward speed of the blade in advance; when about to complete a climb, the system will adjust the target position of the blade back to the design elevation in advance. This "early recovery" avoids the system spending extra time to readjust after exiting a special road section, ensuring the continuity of operation.

[0121] The preset control details provided in this invention specifically describe how to convert pre-perceived information into precise presets of actuator states for two typical working conditions: turning and slope changes. This method not only eliminates the lag in traditional feedback control but also achieves high-precision and high-smoothness autonomous operation of fully hydraulic bulldozers under complex road conditions through strategies such as "preset steering," "smooth transition," and "early recovery."

[0122] This invention provides a specific flow correction method. In S104, the traveling hydraulic control command and the working device hydraulic control command are corrected based on the boundary distance, the line deviation, the working surface deviation, and the hydraulic actuation margin. Specifically, this may include: The available flow rate of the pump source is determined based on the engine speed, the current displacement of the variable pump, the hydraulic oil temperature, and the pump efficiency status.

[0123] In some embodiments, the controller estimates in real time the maximum available flow rate that the hydraulic pump can output under the current conditions. This estimation is not a simple lookup, but rather considers multiple factors. First, the current engine speed is obtained from the engine ECU. Second, the current pump displacement is obtained from the swashplate position sensor. Then, the pump's volumetric efficiency is corrected based on the hydraulic oil temperature (volumetric efficiency decreases at higher temperatures). Finally, the maximum sustainable output flow rate at the current engine speed and displacement is determined by combining the pump's efficiency map (which is pre-stored in the controller). Through this comprehensive calculation of multiple factors, the obtained pump source available flow rate is closer to the actual physical limits, providing a reliable basis for subsequent precise flow allocation.

[0124] The total required flow rate is determined based on the target actions of the steering actuator, the blade lifting actuator, the blade tilting actuator, and the ripper actuator.

[0125] In some embodiments, the controller calculates the target flow rate required by each hydraulic actuator to achieve the initial control command generated in S103. For example, the steering actuator requires a certain flow rate to achieve the speed difference between the left and right motors, and the blade lifting actuator requires flow rate to overcome the load and achieve the target speed. The total required flow rate is obtained by adding up the required flow rates of all actuators that operate simultaneously.

[0126] When the total demand flow exceeds the available flow of the pump source, the flow allocation weight of each actuator is determined based on the basic safety priority, the boundary distance, the line deviation, the working surface deviation, and the pressure proximity of each actuator.

[0127] In some embodiments, when total demand exceeds supply, the system initiates intelligent flow allocation arbitration. Basic safety priorities are preset; for example, steering typically has the highest priority to ensure driving safety. However, this basic priority is not the only determining factor. The system further "examines" the current operational situation. If the boundary distance is small, indicating proximity to a danger zone, the weight of steering is further increased. If the boundary distance is large and the working face deviation is significant, the weight of blade lifting is increased. Furthermore, the pressure proximity of each actuator (i.e., the ratio of current pressure to a safety threshold) is also considered; if an actuator's pressure is already high, its allocation weight is reduced to prevent triggering the overflow valve.

[0128] The target flow of at least one actuator is reduced according to the flow allocation weight, and the reduced flow is allocated to the actuator with higher priority among the steering actuator, the blade lifting actuator, or the blade tilting actuator.

[0129] In some embodiments, the arbitrator redistributes the target flow to each actuator based on a determined final weight. The principle of this redistribution is to reduce the flow target of lower-priority actuators and "transfer" the saved flow to higher-priority actuators. For example, near a boundary, the system might reduce the blade tilt speed (a non-critical action), "giving" flow to the steering system to ensure the vehicle can quickly correct its course away from the boundary. This "lossy" but "safe" redistribution method ensures that, given the system's limited power, the most critical tasks always receive sufficient power support.

[0130] The flow correction method provided in this invention constructs a multi-factor coupled intelligent flow allocation mechanism by combining pump source status, actuator requirements, safety status, and operational quality requirements. This mechanism breaks through the traditional control mode of fixed priority or simple proportional reduction, and can dynamically adjust the control strategy according to the specific operational scenario. When system capacity is limited, it can maximize operational safety and quality, and effectively solve the power allocation problem when the total required flow is insufficient.

[0131] This invention provides a fault-tolerant control method for abnormal positioning signals. The method may further include the following steps: The reliability of the acquired positioning signals, attitude signals, blade position signals, and hydraulic actuation signals.

[0132] In some embodiments, the control system establishes a real-time reliability assessment mechanism for all input signals. For BeiDou positioning signals, reliability may be affected by factors such as the number of satellites, differential signal delay, and multipath effects. For IMU attitude signals, reliability decreases due to integral drift over time. For blade attitude signals, reliability may decrease due to sensor vibration or exceeding the measurement range. The controller continuously calculates the quality factors of these signals, providing a basis for subsequent data fusion and fault-tolerant decisions.

[0133] When the signal reliability of the positioning signal is lower than the positioning reliability threshold, and the signal reliability of the attitude signal and the hydraulic actuation signal meets the dead reckoning conditions, a predetermined estimated trajectory is generated based on the guide corridor direction, vehicle attitude and travel motor speed before failure.

[0134] In some embodiments, the dead reckoning conditions include at least one of the following conditions: The signal reliability of the attitude signal is higher than the attitude reliability threshold, and the integral drift of the attitude signal in the most recent first preset time period is less than the drift upper limit value; wherein, the integral drift includes at least one of the heading angle integral drift and the pitch angle integral drift. The reliability of the hydraulic actuation signal is higher than the speed reliability threshold, and the fluctuation amplitude of the travel motor speed signal is less than the upper limit of fluctuation within the second preset time period, so as to indicate that the current vehicle speed can support the vehicle speed calculation based on the travel motor speed. The current vehicle speed is greater than the minimum speed threshold calculated by dead reckoning, and the current vehicle yaw rate is less than the upper limit of the yaw rate, indicating that the vehicle is not stationary or in an excessively skidding state.

[0135] Optionally, the attitude confidence threshold is the quantization threshold corresponding to the attitude signal quality factor, and the drift upper limit is determined based on the zero-bias stability and sampling period of the inertial measurement unit. For example, the drift upper limit for the yaw angle integral drift can be set to 0.5 degrees / minute to 2 degrees / minute, and the drift upper limit for the pitch angle integral drift can be set to 0.3 degrees / minute to 1 degree / minute. The speed confidence threshold is determined based on the measurement noise and quantization error of the travel motor speed sensor, and the dead reckoning minimum vehicle speed threshold can be set to 0.2 m / s to 0.5 m / s to ensure sufficient linear mapping accuracy between the travel motor speed and vehicle speed. The yaw rate upper limit can be set to 5 degrees / second to 10 degrees / second to exclude abnormal driving states such as sideslip or fishtailing on low-traction surfaces.

[0136] For example, when the positioning signal is lost or the signal reliability is lower than the positioning reliability threshold, if the signal reliability of the attitude signal and the hydraulic actuation signal simultaneously meet the above conditions, it is determined that the dead reckoning conditions are met, and the controller allows entry into the dead reckoning backup positioning mode; if any of the above conditions are not met, it is determined that the dead reckoning conditions are not met, the controller prohibits entry into the dead reckoning mode, and executes a safety strategy of stopping or decelerating to a safe speed.

[0137] In some embodiments, when the system detects a loss of BeiDou RTK signal or an unreliable signal, it does not immediately stop but instead initiates a backup positioning mode based on dead reckoning. The trigger condition is that the IMU and the travel motor speed sensor signals must be reliable. Once the condition is met, the system records the guide corridor direction, vehicle heading, and position at the last moment before the positioning failure. Then, using the acceleration and angular velocity measured by the IMU and the vehicle speed calculated from the travel motor speed, it performs integral calculations to generate a predetermined estimated trajectory, thereby maintaining the estimated vehicle position for a short period.

[0138] The boundary protection zone is expanded according to the predetermined estimated trajectory to reduce the target vehicle speed and limit the downward pressing action of the shovel.

[0139] In some embodiments, upon entering dead reckoning mode, the control system automatically implements a series of conservative safety measures to compensate for the risks associated with decreased positioning accuracy. First, it dynamically expands the boundary protection zone within the guidance corridor, essentially defining a larger "safety zone" for the vehicle and blade in the virtual world to avoid accidental triggering of boundary protection due to position estimation errors. Second, it proactively reduces the target vehicle speed, causing the bulldozer to move slowly and reducing the risk of loss of control. Simultaneously, it restricts the downward movement of the blade to prevent violent cutting operations when the position is unclear. These measures collectively ensure operational safety in "blind guidance" mode.

[0140] When the signal reliability of the positioning signal recovers to above the positioning reliability threshold, the recovered positioning trajectory is smoothly fused with the predetermined estimated trajectory, and the pump displacement, valve opening and actuator target speed are recovered according to the preset slope.

[0141] In some embodiments, when the positioning signal is recovered, the system does not immediately jump to the new positioning data. Instead, it uses a smoothing filter (such as a Kalman filter) to fuse the recovered high-precision positioning trajectory with the estimated trajectory during the failure period, achieving a smooth position transition and avoiding control shocks caused by position jumps. Simultaneously, all pump displacement, valve opening, and actuator target speeds that were restricted during the failure period will gradually recover to normal operating levels according to a preset, gentle slope, thereby achieving seamless and safe recovery of the entire system.

[0142] The fault-tolerant control method provided in this invention significantly improves the reliability and availability of the automatic control system of a fully hydraulic bulldozer in complex environments (such as tunnels, dense forests, and areas with strong electromagnetic interference) by automatically switching to a standby mode based on dead reckoning when the positioning signal is lost, taking a series of conservative measures such as expanding the boundary and reducing the speed, and achieving a smooth transition after the signal is restored. It also solves the technical problem of system loss of control caused by the failure of a single sensor in the prior art.

[0143] This invention also provides a hydraulic-based automatic control and guidance device for bulldozers. For example... Figure 3 As shown, the device may specifically include the following modules: The first generation module 301 is used to generate a guide corridor based on the construction design data; the guide corridor includes a center zone corresponding to the target construction route, a boundary protection zone corresponding to the construction boundary, and a working face control zone corresponding to the target working face.

[0144] The second generation module 302 is used to generate a corridor deviation state based on the bulldozer's body positioning posture data, the bulldozer's blade posture data, and the guide corridor; the corridor deviation state includes at least one of the following: the line deviation of the vehicle body relative to the center zone of the line, the working surface deviation of the blade cutting edge relative to the working surface control zone, the boundary distance of the vehicle body or blade relative to the boundary protection zone, and the hydraulic actuation margin of the full hydraulic system for the line deviation and the working surface deviation.

[0145] The mapping module 303 is used to map the line deviation into a travel hydraulic control command and the working face deviation into a working device hydraulic control command according to the corridor deviation state.

[0146] The correction module 304 is used to correct the travel hydraulic control command and the working device hydraulic control command according to the boundary distance, the line deviation, the working surface deviation and the hydraulic execution margin when the total demand flow corresponding to the travel hydraulic control command and the working device hydraulic control command exceeds the pump source supply flow or the pressure of the full hydraulic system reaches the preset pressure boundary.

[0147] The control module 305 is used to control the travel hydraulic system of the fully hydraulic bulldozer based on the modified travel hydraulic control command, and to control the working device hydraulic system of the fully hydraulic bulldozer based on the modified working device hydraulic control command.

[0148] As the device embodiment is basically similar to the method embodiment, the description is relatively simple, and relevant parts can be found in the description of the method embodiment.

[0149] Combination Figure 4 As shown, this application embodiment provides an electronic device, which may include a processor 10 and a memory 11. Optionally, the electronic device may further include a communication interface 12 and a bus 9. The processor 10, communication interface 12, and memory 11 can communicate with each other via the bus 9. The communication interface 12 can be used for information transmission. The processor 10 can call logical instructions in the memory 11 to execute the hydraulic-based bulldozer automatic control and guidance method of the above embodiment.

[0150] Furthermore, the logical instructions in the aforementioned memory 11 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium.

[0151] The memory 11, as a computer-readable storage medium, can be used to store software programs and computer-executable programs, such as program instructions / modules corresponding to the methods in the embodiments of this application. The processor 10 executes functional applications and data processing by running the program instructions / modules stored in the memory 11, thereby realizing the hydraulic-based bulldozer automatic control and guidance method in the above embodiments.

[0152] The memory 11 may include a program storage area and a data storage area. The program storage area may store the operating system and application programs required for at least one function; the data storage area may store data created based on the use of the electronic device. Furthermore, the memory 11 may include high-speed random access memory and may also include non-volatile memory.

[0153] The embodiments or examples disclosed in this application are not exhaustive, but merely illustrative of some embodiments or examples, and are not intended to limit the scope of protection of this disclosure. Unless contradictory, each step in a particular embodiment or example can be implemented as an independent embodiment, and the steps can be arbitrarily combined. For example, a solution after removing some steps in a particular embodiment or example can also be implemented as an independent embodiment, and the order of the steps in a particular embodiment or example can be arbitrarily interchanged. Furthermore, optional methods or examples in a particular embodiment or example can be arbitrarily combined; moreover, embodiments or examples can be arbitrarily combined. For example, some or all steps of different embodiments or examples can be arbitrarily combined, and a particular embodiment or example can be arbitrarily combined with optional methods or examples of other embodiments or examples.

[0154] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. The device embodiments described above are merely illustrative; for example, the division of units can be a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the displayed or discussed mutual couplings, direct couplings, or communication connections may be through some interfaces; indirect couplings or communication connections between units or modules may be electrical or other forms.

[0155] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0156] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0157] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as a USB flash drive, read-only memory (ROM), random access memory (RAM), portable hard drive, magnetic disk, or optical disk.

[0158] The above are merely preferred embodiments of this application. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A hydraulic-based automatic control and guidance method for bulldozers, characterized in that, include: A guide corridor is generated based on the construction design data; the guide corridor includes a center zone corresponding to the target construction route, a boundary protection zone corresponding to the construction boundary, and a working face control zone corresponding to the target working face. Based on the bulldozer's body positioning posture data, the bulldozer's blade posture data, and the guide corridor, a corridor deviation state is generated; the corridor deviation state includes at least one of the following: the line deviation of the vehicle body relative to the center zone of the line, the working surface deviation of the blade cutting edge relative to the working surface control zone, the boundary distance of the vehicle body or blade relative to the boundary protection zone, and the hydraulic actuation margin of the full hydraulic system for the line deviation and the working surface deviation; Based on the corridor deviation state, the line deviation is mapped to a travel hydraulic control command, and the working face deviation is mapped to a working device hydraulic control command; When the total required flow rate corresponding to the travel hydraulic control command and the working device hydraulic control command exceeds the pump source's available flow rate or the pressure of the full hydraulic system reaches the preset pressure boundary, the travel hydraulic control command and the working device hydraulic control command are corrected according to the boundary distance, the line deviation, the working surface deviation, and the hydraulic execution margin. The travel hydraulic system of the fully hydraulic bulldozer is controlled based on the modified travel hydraulic control command, and the working device hydraulic system of the fully hydraulic bulldozer is controlled based on the modified working device hydraulic control command.

2. The method according to claim 1, characterized in that, The guiding corridor is generated based on the construction design data, including: The allowable lateral deviation of the center zone of the line is determined based on the curvature of the target construction route, the current vehicle speed, the slope of the target working surface, the blade width, and / or the hydraulic execution response time. Based on the operating mode, the target elevation and / or target cross slope of the target working face, determine the allowable overcut and undercut of the control zone of the working face; The guide corridor is generated based on the allowable lateral deviation, the allowable overcut, the allowable undercut, and the construction boundary protection distance.

3. The method according to claim 1 or 2, characterized in that, Based on the corridor deviation state, the line deviation is mapped to travel hydraulic control commands, and the working face deviation is mapped to working device hydraulic control commands, including: The first variable is determined based on the aforementioned line deviation, heading deviation, boundary distance, and / or remaining distance of the road segment; The second variable is determined based on the working surface deviation, the blade lateral tilt angle deviation, and / or the blade attitude deviation relative to the vehicle body; When the boundary distance is greater than the boundary warning distance, the control weight corresponding to the second variable is increased and the correction amplitude corresponding to the first variable is limited. When the boundary distance is less than or equal to the boundary warning distance, the control weight corresponding to the first variable is increased and the shovel pressing speed or shovel cutting depth is limited.

4. The method according to claim 3, characterized in that, Based on the corridor deviation state, the route deviation is mapped to a travel hydraulic control command, and the working face deviation is mapped to a working device hydraulic control command, further comprising: When the correction direction of the line deviation and the correction direction of the working face deviation cause the same hydraulic actuator to generate opposite adjustment requirements, the road section status of the fully hydraulic bulldozer is determined. Based on the road segment status, the adjustment priority order is determined, wherein if the road segment status is a straight bulldozing section, the working face deviation is reduced first; and / or, if the road segment status is a boundary adjacent section, the boundary distance is increased first; and / or, if the road segment status is a turning section, the heading deviation is reduced first; and / or, if the road segment status is a fine leveling section, the elevation deviation and cross slope deviation of the shovel cutting edge are reduced first. Based on the adjustment priority, the working surface deviation is mapped into hydraulic control commands for the working device.

5. The method according to claim 1 or 2, characterized in that, The method further includes: When there are changes in route curvature, changes in target working face slope, narrowing of construction boundary, or switching of operation mode within the current line of sight, a road section buffer zone is generated in the guide corridor; the line of sight is determined based on the current vehicle speed and hydraulic execution response time. Before the fully hydraulic bulldozer enters the buffer zone of the road section, a hydraulic preset command is generated; the hydraulic preset command includes at least two of the following: variable pump displacement preset amount, travel motor displacement transition amount, blade lift valve opening preset amount, and blade tilt valve opening preset amount; Based on the hydraulic preset command, the walking hydraulic system and the working device hydraulic system are preset controlled.

6. The method according to claim 5, characterized in that, Based on the hydraulic preset command, preset control is performed on the walking hydraulic system and the working device hydraulic system, including: When the fully hydraulic bulldozer is about to enter a turning section, reduce the target vehicle speed and limit the blade pressing speed, and adjust the displacement difference between the left and right travel motors according to the curvature radius of the turning section. When the fully hydraulic bulldozer is about to enter the slope change section, the target position of the blade lifting cylinder is adjusted in advance according to the difference between the current vehicle posture and the slope of the target working surface, and the upper limit of the change rate of the blade lifting valve opening is set. When the fully hydraulic bulldozer is about to leave the turning section or the slope change section, the target control value of the blade corresponding to the working face control zone is restored in advance.

7. The method according to claim 1 or 2, characterized in that, Based on the boundary distance, the line deviation, the working surface deviation, and the hydraulic actuation margin, the travel hydraulic control command and the working device hydraulic control command are corrected, including: The available flow rate of the pump source is determined based on the engine speed, the current displacement of the variable pump, the hydraulic oil temperature, and the pump efficiency status. Determine the total required flow rate based on the target actions of the steering actuator, the blade lifting actuator, the blade tilting actuator, and the ripper actuator; When the total demand flow exceeds the available flow of the pump source, the flow allocation weight of each actuator is determined based on the basic safety priority, the boundary distance, the line deviation, the working surface deviation, and the pressure proximity of each actuator. The target flow of at least one actuator is reduced according to the flow allocation weight, and the reduced flow is allocated to the actuator with higher priority among the steering actuator, the blade lifting actuator, or the blade tilting actuator.

8. The method according to claim 1 or 2, characterized in that, The method further includes: The reliability of the acquired positioning signals, attitude signals, blade pose signals, and hydraulic actuation signals; When the signal reliability of the positioning signal is lower than the positioning reliability threshold, and the signal reliability of the attitude signal and the hydraulic actuation signal meets the dead reckoning conditions, a predetermined estimated trajectory is generated based on the guide corridor direction, vehicle attitude and travel motor speed before failure. The boundary protection zone is expanded according to the predetermined estimated trajectory to reduce the target vehicle speed and limit the downward pressing action of the shovel. When the signal reliability of the positioning signal recovers to above the positioning reliability threshold, the recovered positioning trajectory is smoothly fused with the predetermined estimated trajectory, and the pump displacement, valve opening and actuator target speed are recovered according to the preset slope.

9. A hydraulic-based automatic control and guidance device for bulldozers, characterized in that, include: The first generation module is used to generate a guide corridor based on construction design data; the guide corridor includes a center zone corresponding to the target construction route, a boundary protection zone corresponding to the construction boundary, and a working face control zone corresponding to the target working face. The second generation module is used to generate a corridor deviation state based on the bulldozer's body positioning posture data, the bulldozer's blade posture data, and the guide corridor; the corridor deviation state includes at least one of the following: the line deviation of the vehicle body relative to the center zone of the line, the working surface deviation of the blade cutting edge relative to the working surface control zone, the boundary distance of the vehicle body or blade relative to the boundary protection zone, and the hydraulic actuation margin of the full hydraulic system for the line deviation and the working surface deviation; The mapping module is used to map the line deviation into a travel hydraulic control command and the working face deviation into a working device hydraulic control command based on the corridor deviation state. The correction module is used to correct the travel hydraulic control command and the working device hydraulic control command according to the boundary distance, the line deviation, the working surface deviation and the hydraulic execution margin when the total demand flow corresponding to the travel hydraulic control command and the working device hydraulic control command exceeds the pump source supply flow or the pressure of the full hydraulic system reaches the preset pressure boundary. The control module is used to control the travel hydraulic system of the fully hydraulic bulldozer based on the modified travel hydraulic control command, and to control the working device hydraulic system of the fully hydraulic bulldozer based on the modified working device hydraulic control command.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions; when executed by a processor, the computer-executable instructions are able to implement the method described in any one of claims 1 to 8.

Images