A system and method for adaptive threshold seeking

Abstract

The application provides a system and method for adaptive threshold searching, comprising: a left vehicle speed sensor for providing the vehicle speed of the left wheel of the vehicle; a right vehicle speed sensor for providing the vehicle speed of the right wheel of the vehicle; an engine as the power source of the vehicle; a travel pump driven by electric current, wherein the left travel pump controls the left travel system of the vehicle and the right travel pump controls the right travel system of the vehicle; an operating handle, which is subjected to interval first mapping based on the handle opening degree, interval second mapping based on the driving current, and design of the increasing rate and the decreasing rate; and a vehicle controller, which is the integrated unit of the vehicle logic control and the instruction output device. The adaptive threshold searching algorithm system designed by the application collects each input signal according to the speed ratio designed by the driver, manually calibrates, linearly maps and dynamically searches, so as to realize the steering of the left and right wheels in a fixed speed ratio mode, reduce the tire friction and improve the driving experience.

Description

Technical Field

[0001] This invention relates to a system and method for adaptively finding thresholds, belonging to the field of search algorithm technology. Background Technology

[0002] With the accelerating pace of global urbanization, skid steer loaders, due to their compact design and maneuverability, have become ideal technical equipment for mechanized construction in municipal engineering. Urbanization brings a large demand for road, bridge, and municipal engineering projects, but construction sites are often confined to limited space, making it difficult for traditional large equipment to operate. Skid steer loaders not only operate efficiently in confined spaces but also possess multi-functional capabilities, enabling them to perform various tasks such as excavation, loading, and sweeping through quick attachment changes, meeting diverse construction needs, significantly improving construction efficiency, and reducing equipment purchase and maintenance costs. Their versatility and efficiency make them indispensable in urban construction, with broad prospects for future development.

[0003] In ISO mode, the steering handle is operated at a 45-degree angle to turn the skid steer loader left and right. To maintain a fixed turning radius, the left and right wheel speeds must be in a constant ratio at the corresponding engine speed. However, the increasing inconsistency between product batches has become a key factor restricting industry development. Even with the same current applied to the left and right travel pumps, identical driving forces cannot be generated. Therefore, it is necessary to deduce the drive current from the vehicle speed and optimize the handle's analytical parameters. Achieving precise steering control for skid steer loaders is crucial for promoting automated and intelligent control of these products. Therefore, researching and developing an adaptive threshold-finding method is of great significance for improving the operability of skid steer loaders. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide an adaptive threshold finding system and method. It deduces the control-side threshold from the drive-side data, optimizes the handle parsing parameters, and ensures that when the handle is tilted at 45 degrees in ISO mode, the wheel speeds on both sides have a fixed driving speed ratio when turning left or right. Based on the different physical dimensions of the site, the driver can manually set the turning radius according to the construction site to meet the needs of multiple scenarios.

[0005] To achieve the above objectives / to solve the above technical problems, the present invention is implemented using the following technical solution: An adaptive threshold finding system includes: The vehicle speed sensors are installed at the wheel positions on both sides to measure the overall vehicle speed. Based on the detected signal points of the weight pan, the output voltage signal is converted by a preset voltage-speed mapping curve to output the speed of the left wheel and the speed of the right wheel of the vehicle. The operating handle is first mapped to the range based on the inertia of the handle when it returns to center. The handle opening is then mapped to the vehicle control current curve to achieve flexible current transformation. The travel pump is used to control the movement of the entire vehicle. Based on the speed difference between the left and right travel systems, it forms the technical conditions for vehicle 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 drive pump information, and outputs control commands based on the received information.

[0006] Optionally, the vehicle controller communicates with the engine and control lever via CAN, and with the vehicle speed sensor and drive pump via hardwiring.

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

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

[0009] Second aspect: A method for adaptively finding a threshold, the method comprising: Acquire engine speed information, vehicle speed signals for the left and right wheels of the vehicle; The control signal of the operating handle is obtained, and the entire circumference area is divided into constant angle areas using the horizontal and vertical coordinate axes and the diagonal as the dividing reference lines. The attenuation angle is introduced, and combined with the distance between the operating point of the handle and the origin, it is converted into the drive 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, and considering that when the handle is operated at a 45° angle, the left and right steering have a fixed speed ratio and the steering wheel must not be stationary, when the handle operation point enters the constant angle zone, it reverses the lookup based on the composite relationship curve between the driving pump drive current and the vehicle speed obtained by manual calibration, and generates the output command for the driving pump drive current. Based on the output command of the driving pump drive current, when the feedback of the left and right vehicle speed information is not equal to the set ratio of the left and right vehicle speeds, the inverse annealing local optimization algorithm is introduced for secondary optimization, and 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 drive current and the vehicle speed is updated.

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

[0011] Optionally, the manual calibration includes: When the operating handle is operated at a 45-degree angle, the handle operation point enters the constant angle zone. Press the accelerator to control the engine speed. When the engine speed is less than the first preset speed, plot the curve of the relationship between the driving pump current and the vehicle speed at low speed. Plot multiple times and take the average value in the longitudinal direction to obtain the composite curve of the driving pump current and the vehicle speed. When the engine speed is greater than or equal to the second preset speed, repeat the above operation to obtain the composite relationship curve of the driving pump drive current and vehicle speed at high speed, and complete the manual calibration.

[0012] Optionally, the attenuation angle includes: The attenuation angle is the angle between the line connecting the handle operation 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 at its minimum, the handle operating point is on the diagonal of the quadrant; when the attenuation angle is at its maximum, the handle operating point is on the horizontal and vertical axes of the quadrant. Therefore, the range of values ​​for the attenuation angle is... .

[0013] Optionally, the constant angle region includes: dividing the entire circumference into 8 domains using the horizontal and vertical coordinate axes and the diagonal as reference lines; based on the characteristics of the attenuation angle, the attenuation angle near the diagonal is close to 0; and during turning, the attenuation angle has a minimum value. ; When the handle operating point enters the constant angle region, the attenuation angle decreases to... It remains unchanged afterward. Based on the driver's driving habits, the diagonal area of ​​the first quadrant is assigned to the domain II, ensuring that when the handle is operated at a 45° angle in the first quadrant, the left and right side wheels of the vehicle turn to the right and forward at a fixed speed ratio; similarly, the diagonal area of ​​the second quadrant is assigned to the domain III, the diagonal area of ​​the third quadrant is assigned to the domain VI, and the diagonal area of ​​the fourth quadrant is assigned to the domain VII.

[0014] Optionally, the steps of the inverse annealing local optimization algorithm are as follows: Based on the set threshold at the current engine speed and and The ratio determines the current optimization target. Optimization directions; when > When, it means The optimization should aim to decrease the numerical value. The optimization formula introduces two hyperparameters: the reverse annealing factor. and adjustment factor ,in The particles optimized by introducing a reverse annealing factor are more active in the initial stage, but become less active with increasing iterations. As the value increases, the optimization step size gradually decreases, indicating that the particle carefully searches the local region where the optimal value is located and quickly finds the optimal value. The optimal value found by the inverse annealing local optimization algorithm is used to dynamically adjust the composite relationship curve between the driving pump current and vehicle speed at low speeds, and the vehicle controller stores the curve data. Based on the curve optimization of scope I, curve optimization is carried out from scope II to scope VIII.

[0015] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0016] The adaptive threshold optimization algorithm system designed in this invention is based on the premise that the consistency of domestically produced parts is poor and that localization is an inevitable trend. In response to the group's call for the localization of parts, the system collects various input signals according to the speed ratio designed by the driver, performs manual calibration, linear mapping, and dynamic optimization, so that the left and right wheels can achieve steering with a fixed speed ratio when turning, thereby reducing tire friction and improving the driving experience. Attached Figure Description

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

[0018] Figure 2 This is a schematic diagram of the adaptive optimization algorithm system of the present invention;

[0019] Figure 3 This is a flowchart of the adaptive optimization algorithm of this invention;

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

[0021] Figure 5 This invention is a local optimization algorithm based on reverse annealing. Detailed Implementation

[0022] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0023] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are used only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0024] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0025] Example 1: This invention proposes an adaptive threshold finding system, 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 drive pump, a right drive pump, and an operating handle; the left vehicle speed sensor provides feedback on the speed of the left wheels of the vehicle, the right vehicle speed sensor provides feedback on the speed of the right wheels of the vehicle, and the engine provides feedback on the current speed. To prevent accidental touches or to account for inertia when the handle returns to center, a dead zone for the handle opening is designed, i.e., the handle opening is initially mapped within a certain range. To better control the current and meet the control needs of the entire vehicle, the handle opening is mapped a second time to the vehicle control current curve, achieving flexible current transformation. The control signal is input through the handle, and the left and right drive pumps are driven by current. The vehicle controller is the logic processing unit of the entire vehicle and also the output unit for the execution signals.

[0026] The left and right vehicle speed sensors are installed near the wheels and output sensing signals based on the signal points of the detection weight pan; the vehicle controller is installed on the rear side of the cab, which is safe and has low vibration, and is connected to the wiring harness on the pin side.

[0027] The engine is installed in the rear compartment of the vehicle and covered by a rear cover. It is the power source of the entire vehicle and outputs various information about the engine via CAN communication. The travel pump is installed on the bottom side of the cab, slightly rearward. It is driven by current and controls the flow of hydraulic oil. The operating handles are installed on both sides of the cab seat and communicate via CAN. The travel pump drive current is controlled according to the handle opening degree.

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

[0029] When the handle is operated at a 45-degree angle, the handle operation point enters the constant angle zone. Press the accelerator to control the engine speed. When the engine speed is less than 1450 rpm, plot the curve of the relationship between the driving pump current and the vehicle speed at low speed. Plot multiple times and take the average value in the longitudinal direction to obtain the composite curve of the driving pump current and the vehicle speed. When the engine speed is greater than or equal to 1450 rpm, repeat the above operation to obtain the composite curve of the driving pump current and the vehicle speed at high speed, thus completing the manual calibration.

[0030] Due to the unique physical design of skid steer loaders, the left wheel is driven by the left motor and the right wheel is driven by the right motor, resulting in different speeds for the left and right wheels. Therefore, the vehicle speed cannot be obtained through the engine's CAN bus. Instead, a left speed sensor is installed near the left wheel and a right speed sensor is installed near the right wheel. The speed sensor signal is obtained by detecting the signal point using a weight pan, and the speeds of the left and right wheels are calculated based on the voltage-speed curve.

[0031] The operating handle is the input device for the vehicle control signals. Based on the handle opening, the first interval mapping is performed to establish a dead zone. Based on the drive current, the second interval mapping is performed, and the growth rate and reduction rate are designed. The larger the value of the drive current of the travel pump, the larger the opening of the travel pump port, the larger the hydraulic oil flow, the larger the hydraulic energy, and the greater the mechanical energy converted by the drive motor, which manifests as more power for vehicle steering. Conversely, according to the above principle, the smaller the value of the drive current of the travel pump, the smaller the opening of the travel pump port, and the smaller the power for vehicle steering.

[0032] When the handle is operated at a 45-degree angle, it means that the handle operation point coincides with the diagonal, entering the constant angle zone. Based on the composite relationship curve of the drive pump current and vehicle speed obtained from multiple manual calibrations, the value of the drive pump current is found in reverse. According to the engine speed, an appropriate threshold is selected to check whether the speed ratio of the left and right wheels meets the set speed ratio. If it does not meet the set speed ratio, a local dynamic adjustment is performed according to the inverse annealing local optimization algorithm until the speed ratio of the left and right wheels is met, and the composite relationship curve of the drive pump current and vehicle speed is dynamically adjusted.

[0033] Example 2: This invention proposes an adaptive threshold finding method, such as... Figure 2 , Figure 3 As shown, the steps are as follows: Step 1: The vehicle controller acquires signals from the vehicle speed sensor, the handle input signal, and the engine speed signal; The vehicle speed sensor signal is the voltage signal output by the sensor through the signal point of the weight pan. After being mapped by the voltage-speed curve, the vehicle speed value is obtained. Based on the unique physical design of the skid steer loader, there are 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 mapped signal after linear processing. It is artificially designed based on the dead zone and the increase and decrease rate of the drive current. The engine speed can indirectly reflect the current motion state of the machine. When the engine speed is greater than or equal to 1450 rpm, it indicates that the vehicle speed is relatively fast. In order to prevent rollover, the turning radius should be large. When the engine speed is less than 1450 rpm, the vehicle moves slowly. In order to meet the needs of the task or for the sake of control precision, the turning radius should be small. Therefore, the left and right wheel speed ratios at low speeds and at high speeds are set according to different engine speeds. Step 2: Based on the collected signals, the vehicle controller performs logic processing, generates control commands that are transmitted to the drive pump, and makes dynamic adjustments based on feedback. Based on the opening degree of the handle, the initial driving pump current is mapped. When the operating handle enters the constant angle zone, the driving pump driving current and vehicle speed composite relationship curve plotted by manual calibration will be used to reverse the search to find the driving pump driving current that satisfies the left and right vehicle speed ratio and pass it to the driving pump. Based on the feedback of the left and right vehicle speed, local dynamic adjustment will be performed based on the inverse annealing local optimization algorithm until the left and right vehicle speeds meet the set vehicle speed ratio.

[0034] The handle's opening angle is a full-range motion; the handle's specific analysis is as follows: Figure 1 , Figure 4 As shown, the specific steps are as follows: Step 1: Establish a Cartesian coordinate system with the initial position of the handle as the origin; Step 2: Using the horizontal and vertical coordinate axes and the diagonals of the coordinate axes as the dividing baseline, divide the entire handle's active area into 8 domains, labeled as I, II, III, IV, V, VI, VII, and VIII; Domain 1: Left motor drive current = L1, Right motor drive current = L1 * tan(01); Domain 2: Left motor drive current = L2, right motor drive current = L2 * tan(02); Domain 3: Left motor drive current = L3, right motor drive current = L3 * tan(03); Domain 4: Left motor drive current = L4, Right motor drive current = L4 * tan(04); Domain 5: Left motor drive current = L5, right motor drive current = L5 * tan(05); Domain 6: Left motor drive current = L6, right motor drive current = L6 * tan(06); Domain 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 domain 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, and the single-sided range is 1000. Record the distance between the handle operation point and the origin of the coordinate axis as... Then the drive current of the left driving pump and the drive current of the right driving pump are: ; ; Step 4: The driving current of the left and right driving pumps in the domains II, III, IV, V, VI, VII, and VIII is the same as that in the domain I. Based on the design concept of benchmarking competitors and the driving habits of drivers, the diagonal area of ​​the first quadrant is assigned to domain II, the diagonal area of ​​the second quadrant is assigned to domain III, the diagonal area of ​​the third quadrant is assigned to domain VI, and the diagonal area of ​​the fourth quadrant is assigned to domain VII. Step 5: According to the design requirements, when the left and right wheels turn in the same direction and the attenuation angle of the handle operation point is close to 0, the speed of the steering wheel cannot be 0. Therefore, it is necessary to set an angle constant zone, that is, when the attenuation angle decreases to a certain value as the handle operation point decreases, it will no longer decrease and will maintain the current minimum value. The design of the angle constant 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 plot the composite relationship curve of the driving pump drive current and vehicle speed at high speeds; when the speed is less than 1450 rpm, multiple manual calibrations are performed to plot the composite relationship curve of the driving pump drive current and vehicle speed at low speeds.

[0036] The manual calibration steps are as follows: Step 1: Rotate the engine speed knob to control the engine speed below 1450 rpm; Step 2: Record the driving pump current when the vehicle just starts moving, and set it as the reference current, which represents the current that can just drive the left and right motors. Step 3: Collect the vehicle speed on the corresponding side under different drive currents in 30mA increments 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 origin, vehicle speed as the horizontal axis, and driving current as the vertical axis. Take the average value in the vertical direction to construct a composite relationship curve between the driving pump driving current and vehicle speed at low speed. Step 5: Rotate the engine speed knob to control the engine speed above 1450 rpm, and repeat the above steps to construct a composite curve of the driving pump drive current and vehicle speed at high speed.

[0037] The quadratic local optimization algorithm is based on the inverse annealing strategy, specifically as follows: Figure 5 As shown, 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 high engine speed, taking the action domain II as the research scope, let the left and right speed ratio be... The speed on the steering side is recorded as The speed on the non-steering side is recorded as On the composite curve of driving pump current versus vehicle speed at high speeds, the current position is... ,if *a< Then the position at the next moment The formula is as follows: ; in This represents the adjustment factor, which is adjustable and typically ranges from 0.7 to 0.9. The reverse annealing factor is expressed by the following formula: ; Analyzing the above formula, we can see that as the iteration proceeds, It is constantly increasing; at the initial moment, The value is relatively small. Larger; among them, ;when When the value is large, The values ​​are relatively small; in summary, at the initial moment of local optimization, the particles are more active and the exploration step size is larger, aiming to quickly find the optimal point; as the iteration progresses, the activity of the particles gradually decreases, aiming to search more carefully. if *a> Then the position at the next moment The formula is as follows: ; Analyzing the above equation, at the initial moment, The value is relatively small. A larger value indicates that at the initial moment of local optimization, the particles are more active, and the exploration step size is larger, aiming to find the optimal point quickly; when When the value is large, The relatively small value indicates that the activity of the particles gradually decreases as the iteration progresses, aiming to conduct a careful search; according to *a and Comparison of values ​​to determine 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: ; This indicates that a local optimum has been found, so optimization is stopped, and the value is written onto the composite relationship curve of the driving pump current and vehicle speed at high speed. Step 3: Rotate 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 speeds. Hydraulic motors convert hydraulic energy into mechanical energy. Rotational speed is achieved by the impact of hydraulic oil on the motor. The 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. A larger current results in a larger pump port opening, a larger hydraulic oil flow rate, and thus, greater hydraulic energy. Therefore, changing the travel pump drive current directly affects the hydraulic motor's rotational speed. Experiments show that the relationship between the hydraulic motor's rotational speed and the drive current of the left and right travel pumps is not intuitively linear. Due to component consistency issues, travel pumps of the same batch and model exhibit significant errors in their electrical characteristics. The above discussion indicates that it is impossible to solidify constant-range angle threshold parameters in batches using laboratory data. Instead, we must first confirm the composite relationship curve between the travel pump drive current and the motor based on multiple manual calibrations by the driver. Combining this with the conversion relationship between motor speed and vehicle speed, we can derive the composite relationship curve between the travel pump drive current and vehicle speed. Finally, based on the inverse annealing local optimization algorithm, we can achieve dynamic adjustment of the threshold within small ranges.

[0038] The driver controls the drive current of the left and right travel pumps by adjusting the opening of the control lever. The lever's position directly affects the generated control signal and the algorithm's optimization effect. The control lever can move at all angles from its initial position. Using the Cartesian coordinate system's axes and diagonals as reference lines, the control lever's active area is divided into eight domains. Following the design philosophy of competing products and user habits, a 45° angled operation of the lever indicates the minimum speed of the steering wheel and is the node for changing the steering wheel's direction of travel. Within each domain, the lever's operating point changes linearly. By combining the distance between the lever's operating point and the origin of the Cartesian coordinate system, and the attenuation angle value, linear changes in the drive current of the left and right travel pumps can be achieved. Taking the first quadrant as an example, when the lever is operated at a 45° angle along the diagonal, the drive current of the right travel pump drops to its minimum and satisfies the left and right wheel speed ratio. If the drive current of the right travel pump drops too low, the right wheel may not move, causing the right track or tire to frequently rub against the ground, increasing the wear and tear on the right steering device and reducing its service life.

[0039] The attenuation angle represents the angle between the line connecting the current handle operation point and the origin, and the diagonal of the corresponding quadrant. The handle establishes a Cartesian coordinate system with its initial point as the origin, and the range of motion is 1000. Based on the distance from the handle operation point to the origin, combined with the attenuation angle value, the drive current of the left and right travel pumps is calculated and output. When the attenuation angle is... When, it indicates that the current handle operation point is on the horizontal axis. The tangent value is 1, which means that the drive current values ​​of the left and right driving pumps are the same. When the attenuation angle is 0, it means that the handle operation point is on the diagonal. The tangent value of 0 is 0. In the design requirements, when the attenuation angle is 0, the wheel speed on the steering side needs to meet the wheel speed ratio of the left and right sides. That is, it is necessary to divide the angle constant zone near the diagonal. In this zone, 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 description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within 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 at the wheel positions on both sides to measure the overall vehicle speed; Based on the detected signal points of the weight pan, the output voltage signal is converted by the preset voltage-speed mapping curve to output the speed of the left wheel and the speed of the right wheel of the vehicle. The operating handle is first mapped to the range based on the inertia of the handle when it returns to center. The handle opening is then mapped to the vehicle control current curve to achieve flexible current transformation. The travel pump is used to control the movement of the entire vehicle. Based on the speed difference between the left and right travel systems, it forms the technical conditions for vehicle 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 drive pump information, and outputs control commands based on the received information. The vehicle controller uses the acquired handle control signal, left and right vehicle speed signals and engine speed signal to determine the left and right steering ratio when the handle is operated at a 45° angle, and the steering wheel must not be stationary. When the handle operation point enters the constant angle zone, the vehicle controller uses the composite relationship curve of drive pump drive current and vehicle speed obtained by manual calibration to reverse look up and generate the output command of drive pump drive current. Based on the output command of the driving pump drive current, when the feedback of the left and right vehicle speed information is not equal to the set ratio of the left and right vehicle speeds, the inverse annealing local optimization algorithm is introduced for secondary optimization, and 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 drive current and the vehicle speed is updated.

2. The adaptive threshold finding system according to claim 1, characterized in that, The vehicle controller communicates with the engine and control lever via CAN, and with the vehicle speed sensor and drive pump via hardwired connection.

3. The adaptive threshold finding system 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 installed at the left and right wheels respectively. Based on the detected signal points of the weight plate, the output voltage signal is converted by a preset voltage-speed mapping curve to output the speed of the left wheel and the speed of the right wheel of the whole vehicle.

4. The adaptive threshold finding system according to claim 1, characterized in that, The travel pumps include a left travel pump and a right travel pump, which are respectively located at the bottom of the cab.

5. A method for adaptively finding a threshold, characterized in that, The method includes: Acquire engine speed information, vehicle speed signals for the left and right wheels of the vehicle; The control signal of the operating handle is obtained, and the entire circumference area is divided into constant angle areas using the horizontal and vertical coordinate axes and the diagonal as the dividing reference lines. The attenuation angle is introduced, and combined with the distance between the operating point of the handle and the origin, it is converted into the drive 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, and considering that when the handle is operated at a 45° angle, the left and right steering have a fixed speed ratio and the steering wheel must not be stationary, when the handle operation point enters the constant angle zone, it reverses the lookup based on the composite relationship curve between the driving pump drive current and the vehicle speed obtained by manual calibration, and generates the output command for the driving pump drive current. Based on the output command of the driving pump drive current, when the feedback of the left and right vehicle speed information is not equal to the set ratio of the left and right vehicle speeds, the inverse annealing local optimization algorithm is introduced for secondary optimization, and 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 drive current and the vehicle speed is updated.

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

7. The adaptive threshold finding method according to claim 5, characterized in that, The manual calibration includes: When the operating handle is operated at a 45° angle, the handle operation point enters the constant angle zone. Press the accelerator to control the engine speed. When the engine speed is less than the first preset speed, plot the curve of the relationship between the driving pump current and the vehicle speed at low speed. Plot multiple times and take the average value in the longitudinal direction to obtain the composite curve of the driving pump current and the vehicle speed. When the engine speed is greater than or equal to the second preset speed, repeat the above operation to obtain the composite relationship curve of the driving pump drive current and vehicle speed at high speed, and complete the manual calibration.

8. The adaptive threshold finding method according to claim 5, characterized in that, The attenuation angle includes: The attenuation angle is the angle between the line connecting the handle operation 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 at its minimum, the handle operating point is on the diagonal of the quadrant; when the attenuation angle is at its maximum, the handle operating point is on the horizontal and vertical axes of the quadrant. Therefore, the range of values ​​for the attenuation angle is... .

9. The adaptive threshold finding method according to claim 8, characterized in that, The constant angle region includes: using the horizontal and vertical coordinate axes and the diagonal as reference lines, the entire circumference is divided into 8 domains. Based on the characteristics of the attenuation angle, the attenuation angle near the diagonal is close to 0. During turning, the attenuation angle has a minimum value, and... ; When the handle operating point enters the constant angle region, the attenuation angle decreases to... It remains unchanged afterward. Based on the driver's driving habits, the diagonal area of ​​the first quadrant is assigned to the domain II, ensuring that when the handle is operated at a 45° angle in the first quadrant, the left and right side wheels of the vehicle turn to the right and forward at a fixed speed ratio; similarly, the diagonal area of ​​the second quadrant is assigned to the domain III, the diagonal area of ​​the third quadrant is assigned to the domain VI, and the diagonal area of ​​the fourth quadrant is assigned to the domain VII.

10. The adaptive threshold finding method according to claim 5, characterized in that, The steps of the inverse annealing local optimization algorithm are as follows: Based on the set threshold at the current engine speed and and The ratio determines the current optimization target. Optimization directions; when > When, it means The optimization should aim to decrease the numerical value. The optimization formula introduces two hyperparameters: the reverse annealing factor. and adjustment factor ,in The particles optimized by introducing a reverse annealing factor are more active in the initial stage, but become less active with increasing iterations. As the value increases, the optimization step size gradually decreases, indicating that the particle carefully searches the local region where the optimal value is located and quickly finds the optimal value. The optimal value found by the inverse annealing local optimization algorithm is used to dynamically adjust the composite relationship curve between the driving pump current and vehicle speed at low speeds, and the vehicle controller stores the curve data. Based on the curve optimization of scope I, curve optimization is carried out from scope II to scope VIII.

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