System and method for adaptively searching threshold

Abstract

The invention provides a system and method for adaptively searching a threshold value, and the system comprises a left vehicle speed sensor which is used for providing the vehicle speed of a left wheel of a whole vehicle; the right vehicle speed sensor is used for providing the vehicle speed of right wheels of the whole vehicle; the engine is a power source of the whole vehicle; the driving pump is driven by current, the left driving pump controls a left driving system of the whole vehicle, and the right driving pump controls a right driving system of the whole vehicle; operating the handle, performing interval first mapping based on the opening degree of the handle, opening up a dead zone, performing interval second mapping based on the driving current, and designing a growth rate and a reduction rate; the whole vehicle controller and the whole vehicle logic control integrated unit are also instruction output devices. According to the self-adaptive threshold optimization algorithm system designed by the invention, according to the speed ratio artificially designed by a driver, acquisition of each input signal, manual calibration, linear mapping and dynamic optimization, left and right wheels realize steering in a fixed speed ratio mode during steering, tire friction is reduced, and the driving experience is improved.

Description

Technical Field

[0001] The present invention relates to a system and method for adaptively finding a threshold value, belonging to the technical field of search algorithms. Background Art

[0002] With the intensification of global urbanization, skid-steer loaders, with their compact design and flexible steering, have become an ideal technical tool for mechanized construction of municipal projects. Urbanization has brought with it a surge in demand for the construction of roads, bridges, and municipal projects. However, construction sites are often confined, making traditional large-scale equipment difficult to operate. Skid-steer loaders not only operate efficiently in confined spaces but also offer a multi-purpose feature. By quickly changing tools, they can perform multiple operations such as excavation, loading, and cleaning, meeting diverse construction needs, significantly improving construction efficiency, and reducing equipment acquisition and maintenance costs. Their versatility and efficiency make them indispensable in urban construction, and they hold promising prospects for future development.

[0003] In ISO mode, the steering handle is tilted at a 45-degree angle to steer the skid loader left or right. This fixed steering radius requires a fixed ratio of left and right wheel speeds at the corresponding engine speed. Due to the increasing prominence of product batch consistency, which has become a key factor restricting industrial development, the left and right travel pumps cannot generate the same driving force when given the same current. This requires reverse engineering the driving current from the vehicle speed to optimize the handle's analytical parameters. Achieving precise steering control for skid loader products is crucial for promoting automated and intelligent control of skid loader products. Therefore, researching and developing an adaptive threshold-finding method is crucial for improving skid loader operability. Summary of the Invention

[0004] The purpose of the present invention is to overcome the shortcomings of the existing technology and provide a system and method for adaptively finding thresholds, which reversely infer the control-side thresholds from the driving-side data, optimize the handle analysis parameters, ensure that the handle is operated at a 45-degree angle in ISO mode, and the wheel speeds on both sides form a fixed driving speed ratio when turning left or right. Based on the different physical sizes of the use site, the driver can manually set the turning radius according to the construction site to meet the use requirements of multiple scenarios.

[0005] In order to achieve the above objectives / solve the above technical problems, the present invention is implemented by adopting the following technical solutions: A system for adaptively finding a threshold value, comprising: The speed sensor is installed at the wheel position on both sides to measure the speed of the vehicle. According to the detected weight plate signal point, the output voltage signal is converted through the preset voltage-speed mapping curve to output the speed of the left and right wheels of the vehicle. The operating handle performs a first interval mapping of the handle opening based on the inertia of the handle when it returns to the center, and a second mapping of the handle opening to the vehicle control current curve to achieve flexible current conversion; The travel pump is used to control the vehicle's travel. Based on the differential speed of the left and right travel systems, it constitutes the technical condition for the vehicle's steering. The pump core is driven by current, and the current controls the opening of the travel pump. The vehicle controller receives real-time engine speed, vehicle speed sensor and travel pump information, and outputs control instructions based on the received information.

[0006] Optionally, the vehicle controller communicates with the engine and the operating handle via CAN, and communicates with the vehicle speed sensor and the travel pump via hard wiring.

[0007] Optionally, the vehicle speed sensor includes a left speed sensor and a right speed sensor, which are installed on the left wheel and the right wheel respectively. According to the detected signal point of the weight disk, the output voltage signal is converted by a preset voltage-speed mapping curve and output as the left wheel speed and the right wheel speed of the whole vehicle.

[0008] Optionally, the travel pump includes a left travel pump and a right travel pump, which are respectively arranged at the bottom of the cab.

[0009] A second aspect: A method for adaptively finding a threshold, the method comprising: Obtain engine speed information and vehicle left wheel speed signal and vehicle right wheel speed signal; Obtain the control signal of the operating handle, divide the entire circumference into constant angle zones using the horizontal and vertical axes and the diagonal as dividing reference lines, introduce the attenuation angle, and combine it with the distance between the handle operating point and the origin to convert it into the driving current of the left and right travel pumps; The vehicle controller, based on the acquired handle control signal, left and right vehicle speed signals, and engine speed signal, generates an output command for the travel pump drive current by performing a reverse lookup based on the composite relationship curve between the travel pump drive current and vehicle speed obtained through manual calibration, based on the assumption that when the handle is tilted 45°, the left and right steering speeds are fixed, and the steering wheel must not be stationary. When the handle operating point enters the constant angle zone, the vehicle controller generates an output command for the travel pump drive current by performing a reverse lookup based on the composite relationship curve between the travel pump drive current and vehicle speed obtained through manual calibration. According to the output command of the driving pump current, when the feedback left and right vehicle speed information is not equal to the set left and right vehicle speed ratio, the reverse annealing local optimization algorithm is introduced to perform secondary optimization. Iterative optimization is performed based on the feedback information until the optimal angle threshold is found and the composite relationship curve between the driving pump current and vehicle speed is updated.

[0010] Optionally, the composite relationship curve between the driving current of the travel pump and the vehicle speed obtained based on manual calibration includes: The drive current is used as the vertical axis of the Cartesian coordinate system, and the vehicle speed is used as the horizontal axis of the Cartesian coordinate system. A longitudinal comparison is performed based on the data of the last three calibrations. If the deviation is within 5%, it means that the calibration of the three curves is correct. If the deviation exceeds 5%, the curve with a large deviation is an abnormal curve and the driver needs to recalibrate multiple times. Finally, the travel pump driving current and vehicle speed relationship curve constructed based on the calibration operation is subjected to longitudinal mean processing to obtain a composite relationship curve of the travel pump driving current and vehicle speed.

[0011] Optionally, the manual calibration includes: When the operating handle is tilted at 45 degrees, the handle operating point enters the constant angle zone, and the accelerator is stepped on to control the engine speed. When the engine speed is less than a first preset speed, a curve of the relationship between the driving current of the travel pump and the vehicle speed at low speed is plotted. This curve is plotted multiple times, and the longitudinal average is taken to obtain a composite curve of the relationship between the driving current of the travel pump and the vehicle speed. When the engine speed is greater than or equal to the second preset speed, the above operation is repeated to obtain a composite relationship curve between the driving current of the travel pump and the vehicle speed at high speed, thereby completing the manual calibration.

[0012] Optionally, the attenuation angle includes: The attenuation angle is the angle between the line connecting the handle operating point and the origin of the Cartesian coordinate system and the diagonal of the quadrant in which it is located; When the attenuation angle is the smallest, the handle operation point is on the diagonal line of the quadrant. When the attenuation angle is the largest, the handle operation point is on the horizontal and vertical axes of the quadrant. Therefore, the range of the attenuation angle is .

[0013] Optionally, the angle constant area includes: taking the horizontal and vertical axes and the diagonal as reference lines, dividing the entire circumference into 8 scopes, according to the characteristics of the attenuation angle, the attenuation angle near the diagonal is close to 0, and when turning, the attenuation angle has a minimum value, and ; When the handle operating point enters the angle constant area, the attenuation angle decreases to After that, remain unchanged. Among them, based on the driver's driving habits, the diagonal area of the first quadrant is divided into scope II to ensure that when the handle is operated at an angle of 45 degrees in the first quadrant, the left and right wheels of the vehicle turn to the right front with a fixed speed ratio; similarly, the diagonal area of the second quadrant is divided into scope III, the diagonal area of the third quadrant is divided into scope VI, and the diagonal area of the fourth quadrant is divided into scope VII.

[0014] Optionally, the reverse annealing local optimization algorithm steps are as follows: Based on the set threshold value at the current engine speed and and The ratio of Optimization direction; when > When The optimization should be done in the direction of decreasing the value. The optimization formula introduces two hyperparameters, the inverse annealing factor and adjustment factors ,in The particles optimized by introducing the reverse annealing factor are more active at the initial moment. As increases, the optimization step size gradually decreases, which means that the particles search carefully in the local area where the optimal value is located and find the optimal value quickly; Dynamically adjust the composite relationship curve between the driving pump current and vehicle speed at low speed according to the optimal value found by the reverse annealing local optimization algorithm, and the vehicle controller stores the curve data; Based on the curve optimization of scope I, the curve optimization of scope II to scope VIII is carried out.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] The adaptive threshold optimization algorithm system designed in the present invention is based on the poor consistency of domestic parts and the general trend of localization. It responds to the group's call for localization of parts. According to the speed ratio manually designed by the driver, it collects various input signals, manually calibrates, linearly maps, and dynamically optimizes to achieve steering with a fixed speed ratio for the left and right wheels during steering, thereby reducing tire friction and improving the driving experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram of the handle analysis of the present invention;

[0018] Figure 2 Schematic diagram of the adaptive optimization algorithm system of the present invention;

[0019] Figure 3 It is a flow chart of the adaptive optimization algorithm of the present invention;

[0020] Figure 4 This is a schematic diagram of the attenuation angle calculation of the present invention;

[0021] Figure 5 It is a local optimization algorithm based on inverse annealing of the present invention. DETAILED DESCRIPTION

[0022] In order to make the technical means, creative features, objectives and effects achieved by the present invention easier to understand, the present invention is further described below in conjunction with specific implementation methods.

[0023] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0024] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0025] Example 1: The present invention proposes a system for adaptively finding thresholds, such as Figure 1 As shown, it includes a left vehicle speed sensor, a right vehicle speed sensor, an engine, a vehicle controller, a left travel pump, a right travel pump, and an operating handle; the left vehicle speed sensor feeds back the speed of the left wheel of the vehicle, the right vehicle speed sensor feeds back the speed of the right wheel of the vehicle, and the engine feeds back the current speed; The operating handle is designed with a dead zone for handle opening to prevent it from being accidentally touched or based on the inertia when the handle returns to the center. That is, the handle opening is mapped to the first interval. In order to better control the current to meet the control needs of the entire vehicle, the handle opening is mapped twice to the vehicle control current curve to achieve flexible current conversion. The operating handle inputs the control signal, the left travel pump is driven by current, and the right travel pump is driven by current. The vehicle controller is the logic processing unit of the vehicle and also the output unit of the execution signal.

[0026] The left and right speed sensors are installed near the wheels and output sensor signals based on the signal points of the weight plate. The vehicle controller is installed at the rear of the cab in a safe environment with low vibration. The pin side is connected to the wiring harness.

[0027] The engine is installed in the rear compartment of the vehicle and is covered by a rear cover. It is the power source of the vehicle and outputs various engine information via CAN communication. The travel pump is installed at the bottom of the cab, slightly to the rear, and is driven by current to control the flow of hydraulic oil. The operating handle is installed on both sides of the cab seat, communicates via CAN, and controls the travel pump driving current according to the handle opening.

[0028] Implementation principle: When the vehicle is powered on and the ignition is on, the control handle is manually calibrated multiple times.

[0029] When the handle is operated at an angle of 45 degrees, the handle operation point enters the constant angle area, and the accelerator is stepped on to control the engine speed. When the engine speed is less than 1450 rpm, a curve showing the relationship between the driving current of the travel pump and the vehicle speed at low speed is drawn. Draw the curve multiple times and take the vertical average to obtain a composite curve showing the relationship between the driving current of the travel pump and the vehicle speed. When the engine speed is greater than or equal to 1450 rpm, repeat the above operation to obtain a composite curve showing the relationship between the driving current of the travel pump and the vehicle speed at high speed, thus completing manual calibration.

[0030] Based on the unique physical design of the skid loader, the left wheel is driven by the left motor and the right wheel is driven by the right motor. The speeds of the left and right wheels are different, so the vehicle speed cannot be obtained through the engine CAN output. A left speed sensor is installed near the left wheel of the vehicle, and a right speed sensor is installed near the right wheel of the vehicle. The speed sensor signal is obtained by detecting the signal point through the weight plate, and the left wheel speed and the right wheel speed of the vehicle are obtained according to the voltage-speed curve.

[0031] The operating handle is the input device of the vehicle control signal. The interval is first mapped based on the handle opening to open up the dead zone. The interval is secondarily mapped based on the driving current, and the growth rate and reduction rate are designed. The larger the driving current value of the driving pump, the larger the driving pump port opening, the greater the hydraulic oil flow, the greater the hydraulic energy, and the greater the mechanical energy converted by the driving motor, which is manifested as more power for the steering of the whole vehicle. Conversely, according to the above principle, the smaller the driving current value of the driving pump, the smaller the driving pump port opening, and the smaller the steering power of the whole vehicle.

[0032] When the handle is operated at a 45-degree angle, it means that the handle operation point coincides with the diagonal line, entering the angle constant area. Based on the composite relationship curve of the driving pump drive current and vehicle speed obtained through multiple manual calibrations, the driving pump drive current value is reversely searched. According to the engine speed, an appropriate threshold is selected to detect whether the left and right wheel speeds meet the set speed ratio. If not, local dynamic adjustments are performed according to the reverse annealing local optimization algorithm until the left and right wheel speed ratio is met, and dynamic adjustments are made to the composite relationship curve of the driving pump drive current and vehicle speed.

[0033] Example 2: The present invention proposes a method for adaptively finding a threshold value, such as Figure 2 、 Figure 3 As shown, the steps are as follows: Step 1: The vehicle controller obtains the vehicle speed sensor signal, handle input signal and engine speed signal; The vehicle speed sensor signal is the voltage signal output by the sensor after detecting the signal point of the weight plate, and the speed value of the vehicle is obtained through voltage-speed curve mapping. Based on the unique physical design of the skid loader, it is divided into left and right vehicle speeds. The wheels on both sides are driven by independent motors on the corresponding sides, and steering is achieved based on the speed difference between the two sides. The handle signal is a mapping signal after linear processing and is artificially designed based on the dead zone and the increase and decrease rates of the driving current. The engine speed can indirectly reflect the current movement state of the whole machine. When the engine speed is greater than or equal to 1450 rpm, it means that the vehicle is traveling at a fast speed. In order to prevent rollover, the turning radius should be large. When the engine speed is less than 1450 rpm, the vehicle is traveling slowly. In order to meet the task requirements or based on the consideration of control accuracy, the turning radius should be small. Therefore, according to the different engine speeds, the left and right measuring wheel speed ratios at low speeds and the left and right side wheel speed ratios at high speeds are set respectively. Step 2: Based on the collected signals, the vehicle controller performs logical processing and transmits the generated control instructions to the travel pump, which is then dynamically adjusted based on the feedback. According to the opening degree of the handle, it is mapped into the driving current of the driving pump at the initial moment. When the operating handle enters the constant angle area, it will reversely search based on the composite relationship curve of the driving pump driving current and vehicle speed drawn by manual calibration to find the driving pump driving current that meets the left and right vehicle speed ratio and transmit it to the driving pump; according to the feedback of the left and right vehicle speeds, local dynamic adjustment is performed based on the inverse annealing local optimization algorithm until the left and right vehicle speeds meet the set speed ratio.

[0034] The handle opening is full angle movement, the handle analysis is as follows Figure 1 、 Figure 4 The specific steps are as follows: Step 1: Establish a Cartesian coordinate system with the initial position of the handle as the coordinate origin; Step 2: Using the horizontal and vertical axes and the diagonal lines of the axes as dividing reference lines, divide the entire handle activity range into 8 scopes, and mark them as I, II, III, IV, V, VI, VII, and VIII; Scope 1: Left motor drive current = L1, right motor drive current = L1*tan(01); Scope 2: Left motor drive current = L2, right motor drive current = L2*tan(02); Scope 3: Left motor drive current = L3, right motor drive current = L3*tan(03); Scope 4: Left motor drive current = L4, right motor drive current = L4*tan(04); Scope 5: Left motor drive current = L5, right motor drive current = L5*tan(05); Scope 6: Left motor drive current = L6, right motor drive current = L6*tan(06); Scope 7: Left motor drive current = L7, right motor drive current = L7*tan(07); Scope 8: Left motor drive current = L8, right motor drive current = L8*tan(08); Step 3: Taking scope I as an example, the left motor drives forward, the right motor drives backward, the vehicle turns right, the wheel speed of the left motor is greater than the wheel speed of the right motor, the handle moves at all angles, the single-side range is 1000, and the distance between the handle operating point and the coordinate axis origin is , then the driving current of the left travel pump and the driving current of the right travel pump are: ; ; Step 4: The driving currents of the left and right driving pumps in scopes II, III, IV, V, VI, VII, and VIII are the same as those in scope I. Based on the design concept of competitive products and the driving habits of drivers, the diagonal area of the first quadrant is divided into scope II, the diagonal area of the second quadrant is divided into scope III, the diagonal area of the third quadrant is divided into scope VI, and the diagonal area of the fourth quadrant is divided into scope VII; Step 5: According to the design requirements, when the left and right wheels steer in unison and the attenuation angle of the handle operating point is close to 0, the speed of the steering wheel cannot be 0. Therefore, a constant angle zone needs to be set. That is, when the attenuation angle decreases to a certain value as the handle operating point decreases, it will no longer decrease and maintain the current minimum value. The design of the constant angle zone is based on manual calibration.

[0035] Based on the engine speed reading, when the speed is greater than or equal to 1450 rpm, multiple calibrations are performed to draw a composite relationship curve between the travel pump drive current and vehicle speed at high speed; when the speed is less than 1450 rpm, multiple manual calibrations are performed to draw a composite relationship curve between the travel pump drive current and vehicle speed at low speed.

[0036] The steps for manual calibration are as follows: Step 1: Turn the engine speed knob to control the engine speed below 1450 rpm; Step 2: Record the driving current of the driving pump when the vehicle is just moving, and set it as the reference current, which represents the current that can just drive the left and right motors; Step 3: Using 30mA as a step, collect the speed of the corresponding side of the vehicle at different drive currents until the drive current reaches the rated maximum value; Step 4: To reduce errors, repeat the above experiment multiple times. Establish a Cartesian coordinate system with the initial position of the operating handle as the coordinate origin, the vehicle speed as the horizontal axis coordinate, and the drive current as the vertical axis coordinate. Take the vertical mean value and construct a composite relationship curve between the driving pump drive current and vehicle speed at low speed. Step 5: Turn the engine speed knob to control the engine speed above 1450 rpm. Repeat the above steps to construct a composite relationship curve between the driving pump current and vehicle speed at high speed.

[0037] The quadratic local optimization algorithm is based on the reverse annealing strategy, as shown in the following example: Figure 5 The implementation steps are as follows: Step 1: If the current engine speed is greater than or equal to 1450 rpm, under the background of large speed, take scope II as the research range and set the left and right speed ratio to , the speed of the vehicle on the steering side is recorded as , the non-steering side speed is recorded as On the composite relationship curve of driving pump current and vehicle speed at high speed, the current position is ,if *a< , then the position at the next moment The formula is as follows: ; in Indicates the adjustment factor, which is adjustable and generally ranges from 0.7 to 0.9; Represents the reverse annealing factor, which is calculated as follows: ; Analyzing the above formula, we can find that as the iteration proceeds, In the continuous growth; at the initial moment, The value is relatively small. Larger; among them, ;when When the value is large, The value is relatively small. In summary, at the initial moment of local optimization, particles are more active and the exploration step size is larger, aiming to quickly find the optimal point. As the iteration proceeds, the activity of particles gradually decreases, aiming to search carefully. if *a> , then the position at the next moment The formula is as follows: ; Analyzing the above formula, at the initial moment, The value is relatively small. Larger, indicating that at the initial moment of local optimization, the particles are more active and the exploration step is larger, aiming to quickly find the optimal point; when When the value is large, A relatively small value indicates that as the iteration proceeds, the activity of the particles gradually decreases, aiming at a careful search; according to *a and Compare the values and judge The direction of change, when *a< hour, Move to the right of the curve. The value is increasing; when *a> hour, Move to the left of the curve. The value is decreasing; Step 2: Iterative Optimization ,when When the following conditions are met: ; It indicates that the local optimum has been found, the optimization is stopped, and the value is written into the composite relationship curve of the driving pump current and vehicle speed at high speed; Step 3: Turn the engine speed knob to control the engine speed below 1450 rpm, repeat the above local optimization process, and optimize the composite relationship curve between the driving pump drive current and vehicle speed at low speed; Hydraulic motors convert hydraulic energy into mechanical energy. Rotational speed is achieved by the hydraulic oil impacting the motor. Hydraulic energy is related to the drive current of the travel pumps. Specifically, the drive current of the left and right travel pumps is positively correlated with the pump port opening. The greater the current, the wider the pump port opening, the greater the hydraulic oil flow rate, and the greater the hydraulic energy. Therefore, the hydraulic motor speed can be directly influenced by varying the drive current of the travel pumps. Experimental results show that the relationship between hydraulic motor speed and the drive current of the left and right travel pumps is not a straightforward linear relationship. Due to component consistency, the electrical characteristics of travel pumps of the same model and batch can vary significantly. The above discussion demonstrates that it is impossible to solidify the constant zone angle threshold parameters in batches using laboratory data. Instead, the driver can first manually calibrate the parameters multiple times to determine the composite curve between the travel pump drive current and the motor. This, combined with the conversion relationship between motor speed and vehicle speed, yields the composite curve between the travel pump drive current and vehicle speed. Finally, a reverse annealing local optimization algorithm is employed to dynamically adjust the threshold between sub-zones.

[0038] The driver's joystick opening controls the drive current to the left and right travel pumps. The handle's resolution directly influences the generated control signals and the algorithm's optimization performance. The joystick can be moved throughout its initial position. The range of the joystick's movement is divided into eight domains, based on the Cartesian coordinate axes and diagonals. Based on the design philosophy of competing products and user habits, a 45-degree angle of the joystick indicates the minimum speed of the steering wheel and marks the point at which the steering wheel changes direction. Within each domain, the joystick operating point varies linearly. The linear variation of the drive current to the left and right travel pumps is achieved by combining the distance between the joystick operating point and the Cartesian coordinate origin and the decay angle. For example, in the first quadrant, when the joystick is operated diagonally at a 45-degree angle, the drive current to the right travel pump is minimized, maintaining the left-right wheel speed ratio. If the right travel pump's drive current drops too low, the right wheel will become immobile, causing the right track or tire to rub against the ground frequently, increasing wear and reducing the service life of the right steering mechanism.

[0039] The attenuation angle represents the angle between the line connecting the current handle operating point and the origin and the diagonal line of the quadrant in which it is located. The handle constructs a Cartesian coordinate system with the initial point as the coordinate origin, and the active range is 1000. The calculation and output of the driving current of the left and right travel pumps are realized based on the distance from the handle operating point to the coordinate origin and the value of the attenuation angle. When the attenuation angle is When , it means that the current handle operation point is on the horizontal axis. The tangent value of is 1, indicating that the driving current values of the left and right driving pumps are the same; when the attenuation angle is 0, it means that the handle operating point is on the diagonal line, and the tangent value of 0 is 0. In the design requirements, when the attenuation angle is 0, the steering side wheel speed needs to conform to the left and right side wheel speed ratio, that is, it is necessary to divide the angle constant zone near the diagonal line. In this area, the attenuation angle value remains unchanged. The angle threshold of the angle constant zone is calculated and inferred based on the adaptive optimization algorithm.

[0040] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A system for adaptively finding a threshold, characterized in that: include: Vehicle speed sensors are installed on the wheels on both sides to measure the vehicle speed; According to the detected weight plate signal point, the output voltage signal is converted by the preset voltage-speed mapping curve to output the left wheel speed and the right wheel speed of the whole vehicle; The operating handle performs a first interval mapping of the handle opening based on the inertia of the handle when it returns to the center, and a second mapping of the handle opening to the vehicle control current curve to achieve flexible current conversion; The travel pump is used to control the vehicle's travel. Based on the differential speed of the left and right travel systems, it constitutes the technical condition for the vehicle's steering. The pump core is driven by current, and the current controls the opening of the travel pump. The vehicle controller receives real-time engine speed, vehicle speed sensor and travel pump information, and outputs control instructions based on the received information.

2. The system for adaptively finding a threshold value according to claim 1, characterized in that: The vehicle controller communicates with the engine and the operating handle via CAN, and communicates with the vehicle speed sensor and the travel pump via hard wiring.

3. The system for adaptively finding a threshold value according to claim 1, characterized in that: The vehicle speed sensor includes a left vehicle speed sensor and a right vehicle speed sensor, which are respectively installed on the left wheel and the right wheel. According to the detected weight plate signal point, the output voltage signal is converted through a preset voltage-speed mapping curve and output as the left wheel speed and the right wheel speed of the whole vehicle.

4. The system for adaptively finding a threshold value according to claim 1, characterized in that: The travel pump comprises a left travel pump and a right travel pump, which are respectively arranged at the bottom of the cab.

5. A method for adaptively finding a threshold, characterized in that: The method comprises: Obtain engine speed information and vehicle left wheel speed signal and vehicle right wheel speed signal; Obtain the control signal of the operating handle, divide the entire circumference into constant angle zones using the horizontal and vertical axes and the diagonal as dividing reference lines, introduce the attenuation angle, and combine it with the distance between the handle operating point and the origin to convert it into the driving current of the left and right travel pumps; The vehicle controller, based on the acquired handle control signal, left and right vehicle speed signals, and engine speed signal, generates an output command for the travel pump drive current by performing a reverse lookup based on the composite relationship curve between the travel pump drive current and vehicle speed obtained through manual calibration, based on the assumption that when the handle is tilted 45°, the left and right steering speeds are fixed, and the steering wheel must not be stationary. When the handle operating point enters the constant angle zone, the vehicle controller generates an output command for the travel pump drive current by performing a reverse lookup based on the composite relationship curve between the travel pump drive current and vehicle speed obtained through manual calibration. According to the output command of the driving pump current, when the feedback left and right vehicle speed information is not equal to the set left and right vehicle speed ratio, the reverse annealing local optimization algorithm is introduced to perform secondary optimization. Iterative optimization is performed based on the feedback information until the optimal angle threshold is found and the composite relationship curve between the driving pump current and vehicle speed is updated.

6. The method for adaptively finding a threshold value according to claim 5, characterized in that: The composite relationship curve between the driving current of the travel pump and the vehicle speed obtained based on manual calibration includes: The drive current is used as the vertical axis of the Cartesian coordinate system, and the vehicle speed is used as the horizontal axis of the Cartesian coordinate system. A longitudinal comparison is performed based on the data of the last three calibrations. If the deviation is within 5%, it means that the calibration of the three curves is correct. If the deviation exceeds 5%, the curve with a large deviation is an abnormal curve and the driver needs to recalibrate multiple times. Finally, the travel pump driving current and vehicle speed relationship curve constructed based on the calibration operation is subjected to longitudinal mean processing to obtain a composite relationship curve of the travel pump driving current and vehicle speed.

7. The method for adaptively finding a threshold value according to claim 5, characterized in that: The manual calibration includes: When the operating handle is tilted at 45 degrees, the handle operating point enters the constant angle zone, and the accelerator is stepped on to control the engine speed. When the engine speed is less than a first preset speed, a curve of the relationship between the driving current of the travel pump and the vehicle speed at low speed is plotted. This curve is plotted multiple times, and the longitudinal average is taken to obtain a composite curve of the relationship between the driving current of the travel pump and the vehicle speed. When the engine speed is greater than or equal to the second preset speed, the above operation is repeated to obtain a composite relationship curve between the driving current of the travel pump and the vehicle speed at high speed, thereby completing the manual calibration.

8. The method for adaptively finding a threshold value according to claim 5, characterized in that: The attenuation angle includes: The attenuation angle is the angle between the line connecting the handle operating point and the origin of the Cartesian coordinate system and the diagonal of the quadrant in which it is located; When the attenuation angle is the smallest, the handle operation point is on the diagonal line of the quadrant. When the attenuation angle is the largest, the handle operation point is on the horizontal and vertical axes of the quadrant. Therefore, the range of the attenuation angle is .

9. The method for adaptively finding a threshold value according to claim 8, characterized in that: The angle constant area includes: taking the horizontal and vertical axes and the diagonal as the reference lines, the whole circumference area is divided into 8 scopes. According to the characteristics of the attenuation angle, the attenuation angle near the diagonal is close to 0. When turning, the attenuation angle has a minimum value, and ; When the handle operating point enters the angle constant area, the attenuation angle decreases to After that, remain unchanged. Among them, based on the driver's driving habits, the diagonal area of the first quadrant is divided into scope II to ensure that when the handle is operated at an angle of 45 degrees in the first quadrant, the left and right wheels of the vehicle turn to the right front with a fixed speed ratio; similarly, the diagonal area of the second quadrant is divided into scope III, the diagonal area of the third quadrant is divided into scope VI, and the diagonal area of the fourth quadrant is divided into scope VII.

10. The method for adaptively finding a threshold value according to claim 5, characterized in that: The steps of the reverse annealing local optimization algorithm are as follows: Based on the set threshold value at the current engine speed and and The ratio of Optimization direction; when > When The optimization should be done in the direction of decreasing the value. The optimization formula introduces two hyperparameters, the inverse annealing factor and adjustment factors ,in The particles optimized by introducing the reverse annealing factor are more active at the initial moment. As increases, the optimization step size gradually decreases, which means that the particles search carefully in the local area where the optimal value is located and find the optimal value quickly; Dynamically adjust the composite relationship curve between the driving pump current and vehicle speed at low speed according to the optimal value found by the reverse annealing local optimization algorithm, and the vehicle controller stores the curve data; Based on the curve optimization of scope I, the curve optimization of scope II to scope VIII is carried out.

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