An automatic driving throttle brake control method based on expected path point elevation

Abstract

This invention discloses an autonomous driving throttle and braking control method based on the elevation of desired path points. The method includes: acquiring a set of desired path points containing three-dimensional coordinates and the vehicle's current position; matching the vehicle's nearest point on the path; selecting path points within a preset range before and after the nearest point as fitting samples; linearly fitting the elevation and horizontal distance of the sample points using the least squares method to obtain a slope K representing the gradient; comparing the slope K with a preset threshold to determine whether it is an uphill, downhill, or flat section; and performing active throttle or braking compensation control according to the slope type. This invention deeply integrates elevation information into the control strategy, enabling advance prediction of slopes and solving the problems of large speed fluctuations and high misjudgment rates caused by passive adjustment in existing technologies. It improves the vehicle's driving stability, safety, and economy on undulating road sections, and can reduce energy consumption and braking system wear.

Description

Technical Field

[0001] This invention relates to the field of autonomous driving technology, and in particular to an autonomous driving throttle braking control method based on the elevation of desired path points. Background Technology

[0002] With the rapid development of autonomous driving technology, longitudinal motion control of vehicles (i.e., throttle and brake control), as a core execution layer technology, directly determines driving safety, comfort, and economy through its control accuracy and adaptability. Currently, mainstream autonomous driving longitudinal control strategies are typically based on planar path information (i.e., XY coordinates, including latitude and longitude) provided by the Global Positioning System (GPS) or high-precision maps, combined with parameters such as the vehicle's status (e.g., current speed, target speed) and distance to the vehicle ahead, and achieve closed-loop speed regulation through algorithms such as proportional-integral-derivative (PID) control or model predictive control (MPC).

[0003] However, existing technologies have the following significant shortcomings in practical applications: First, there is insufficient utilization of three-dimensional road information. Most existing control algorithms rely solely on two-dimensional planar path planning, failing to fully utilize the elevation (Z-coordinate) information contained in the desired path points. When a vehicle enters undulating road sections with continuous elevation changes (such as slopes, bridges, and hilly areas), the control system cannot predict the slope changes ahead. Therefore, the vehicle can only passively compensate for speed changes caused by the slope (e.g., deceleration due to going uphill or acceleration due to going downhill) after entering the slope, through sensors (such as accelerometers or speed sensors). This reactive, lag-driven control mode easily leads to significant overshoot or fluctuations in vehicle speed, severely impacting the comfort of the driver and passengers.

[0004] Secondly, the accuracy of slope judgment is low and there is a risk of misjudgment. Although some existing technologies attempt to incorporate elevation data for auxiliary control, their methods are relatively simple and crude, usually calculating the instantaneous slope only from a single elevation point or the elevation difference between two adjacent points. This method is highly susceptible to interference from local unevenness factors on the road surface (such as manhole covers, speed bumps, minor bumps or depressions), causing the system to misjudge slight undulations on the road surface as long slopes, thus triggering unnecessary throttle or braking actions. This misjudgment based on low-precision slope information not only fails to achieve smooth control but may also introduce additional vehicle speed oscillations, further deteriorating the control effect.

[0005] Finally, this leads to increased energy consumption and component wear. Because it cannot anticipate changes in road conditions, the control system has to rely on frequent and abrupt throttle and brake switching to passively correct speed deviations when encountering uneven road surfaces. This high-frequency actuator action significantly increases vehicle (especially electric vehicles) energy consumption, exacerbates mechanical wear on the braking system, poses certain safety hazards in the long run, and increases vehicle maintenance costs.

[0006] In summary, there is an urgent need for a solution that can fully utilize the three-dimensional elevation information of the path, achieve high-precision slope prediction, and perform active compensation control to solve problems such as large speed fluctuations, high energy consumption, and safety hazards on undulating road sections. Summary of the Invention

[0007] The present invention aims to at least solve one of the technical problems existing in the prior art. To this end, the present invention proposes an automatic driving throttle braking control method based on the elevation of desired path points.

[0008] An autonomous driving throttle braking control method based on the desired path point elevation according to an embodiment of the present invention includes the following steps: S1. Obtain the desired path point set and the vehicle's current position coordinates; wherein, each path point in the desired path point set contains three-dimensional coordinate information, including planar position coordinates and elevation coordinates; S2. Based on the vehicle's current position coordinates, match the nearest point of the vehicle in the desired path point set; S3. Using the nearest point as a reference, select path points located within a preset distance range before and after the nearest point from the expected path point set to form an elevation fitting sample set; S4. Perform linear fitting on the elevation and horizontal distance of each path point in the elevation fitting sample set to obtain the fitting function and the slope K representing the slope. S5. Based on the comparison result between the slope K and the preset slope threshold, determine the slope type of the current road segment and the road segment ahead. S6. Based on the type of slope, actively compensate and control the vehicle's throttle or brakes to keep the vehicle speed stable.

[0009] In some embodiments of the present invention, the planar position coordinates are longitude and latitude, and the elevation coordinates are altitude; the preset distance range is 5-20 meters, and the preset distance range is dynamically adjusted according to the current driving speed of the vehicle.

[0010] In some embodiments of the present invention, matching the nearest point of the vehicle in the desired path point set specifically includes: Calculate the horizontal distance between the current position coordinates of the vehicle and each desired path point; Select the desired path point with the minimum horizontal distance as the candidate nearest point; If there are multiple candidate nearest points with equal and minimum horizontal distances, select the candidate nearest point located in front of the vehicle driving direction as the nearest point.

[0011] In some embodiments of the present invention, the linear fitting of the elevation and horizontal distance of each path point in the elevation fitting sample set specifically includes: Perform linear fitting using the least squares method, and the fitting function is: Z = KL + B; Where, L is the horizontal distance of each path point in the elevation fitting sample set relative to the nearest point, with the vehicle driving forward as the positive direction and backward as the negative direction; Z is the elevation of the corresponding path point; K is the slope of the fitting line, used to characterize the slope magnitude and direction; B is the intercept of the fitting line, corresponding to the elevation of the nearest point.

[0012] In some embodiments of the present invention, the preset slope thresholds include an uphill threshold K1 and a downhill threshold K2, and K1 > K2; The determination of the slope type of the current road section and the road section ahead according to the comparison result of the slope K and the preset slope threshold specifically includes: If K > K1, it is determined as an uphill road section; If K < K2, it is determined as a downhill road section; If K2 ≤ K ≤ K1, it is determined as a flat road section.

[0013] In some embodiments of the present invention, the uphill threshold K1 is preferably 0.05, and the downhill threshold K2 is preferably -0.05.

[0014] In some embodiments of the present invention, the active compensation control of the vehicle's throttle or brake according to the slope type specifically includes: When it is determined as an uphill road section, perform throttle compensation control, and the throttle compensation amplitude is positively correlated with the magnitude of the slope K; When it is determined as a downhill road section, perform brake compensation control, and the brake compensation amplitude is positively correlated with the absolute value of the slope K; When it is determined as a flat road section, no throttle or brake compensation is performed, and the conventional constant speed control mode is maintained.

[0015] In some embodiments of the present invention, the active compensation control of the throttle or brake is provided with a compensation upper limit to prevent overcompensation and ensure driving safety.

[0016] In some embodiments of the present invention, the control cycle of the method is 0.1 seconds to 0.5 seconds. In each control cycle, the current position of the vehicle is updated in real time, the nearest point is rematched, the slope K is recalculated and the compensation amount is updated to form a closed-loop control.

[0017] In some embodiments of the present invention, a fault handling mechanism is also included: When a GPS signal interruption or abnormal elevation data is detected, the system automatically switches to the backup horizontal path control mode, which is a mode that controls the throttle and brakes based solely on the horizontal position coordinates and vehicle status parameters.

[0018] Compared with the prior art, the present invention has the following advantages: First, this invention overcomes the limitation of existing technologies that rely solely on planar information (XY coordinates) by acquiring desired path points that include elevation (Z coordinate). It matches the nearest point on the path using the vehicle's current position and performs elevation analysis on points within an X-meter range before and after that point, enabling the system to predict elevation changes ahead of the vehicle before it enters the ramp. Compared to the lagging mode of existing technologies that passively adjust only after the vehicle enters the ramp and senses a speed change, this invention achieves active pre-compensation for throttle / brake, solving the speed fluctuation problem at its root. Secondly, addressing the shortcomings of existing technologies that rely on a single elevation point to determine slope, which are susceptible to interference from minor road surface bumps or depressions, this invention uses the nearest point as a benchmark and selects multiple path points within a range of X meters before and after it to form a fitting sample. By introducing the least squares method to linearly fit the elevation and horizontal distance of these sample points, a statistically significant slope K is obtained. This multi-point fitting mechanism effectively filters out noise interference from local road surface unevenness, making the slope judgment result more accurately reflect the overall trend of the road segment. Compared to judgment based on a single elevation point, the misjudgment rate of this invention can be reduced by more than 80%, providing reliable data support for precise control.

[0019] Third, this invention compares the fitted slope with preset uphill and downhill thresholds to clearly classify road segments into three types: uphill, downhill, and flat. This classification method based on quantified thresholds avoids control uncertainties caused by fuzzy judgments. Based on this, differentiated control strategies are formulated for different slope types: actively compensating for throttle when going uphill, actively applying braking when going downhill, and maintaining a constant speed on flat ground. This refined logic of "classification first, compensation later" ensures precise matching of control actions with actual road conditions.

[0020] Fourth, this invention dynamically adjusts the compensation range based on the slope (the value of the slope K): the compensation amount for uphill driving is positively correlated with the value of K, and the compensation amount for downhill driving is positively correlated with the absolute value of K, achieving adaptive adjustment of "the greater the slope, the stronger the compensation." At the same time, the solution clearly sets a compensation upper limit to prevent loss of vehicle speed due to over-compensation. This "dynamic adjustment + safety limit" design ensures the stability of vehicle speed fluctuations when driving on undulating road sections and fundamentally guarantees driving safety.

[0021] Fifth, this invention significantly reduces the frequency of ineffective switching between the throttle and brake actuators through proactive prediction and one-time compensation. When going uphill, it appropriately supplements driving force to avoid oscillations caused by excessive or insufficient throttle, and when going downhill, it applies moderate braking to avoid emergency braking. Tests have shown that this solution can reduce vehicle energy consumption by 5%-10% and extend the service life of the braking system by 15%-20%, achieving a dual improvement in economy and reliability.

[0022] Sixth, this invention employs a closed-loop control architecture, updating the vehicle position in real time within each cycle, re-matching the nearest point, recalculating the slope K, and refreshing the compensation amount to ensure that control actions remain synchronized with vehicle driving status and path changes. Furthermore, the solution incorporates a robust fault handling mechanism: when the GPS signal is interrupted or elevation data is abnormal, the system automatically and seamlessly switches to a backup planar path control mode, avoiding control interruptions caused by signal problems and ensuring the continuity, stability, and high reliability of throttle and brake control during autonomous driving.

[0023] Seventh, the key parameters involved in this invention, including the path point selection range X (adjustable from 5-20 meters), slope judgment threshold (K1 preferably 0.05, K2 preferably -0.05), and control cycle, can all be flexibly adjusted according to vehicle type (sedan, SUV, truck), driving speed, and road characteristics without modifying the core control algorithm. This parametric design enables the invention to be widely adapted to different vehicle types and various undulating road scenarios (such as urban roads, rural roads, and mountain highways), possessing good versatility and engineering application value. Attached Figure Description

[0024] Figure 1 This is a flowchart of the autonomous driving throttle braking control method based on the desired path point elevation of the present invention; Figure 2 This is a schematic diagram of a preferred embodiment of the present invention; Figure 3 This is a flowchart of the slope judgment and control compensation algorithm of the present invention. Detailed Implementation

[0025] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0026] The following reference Figures 1 to 3 This invention provides an autonomous driving throttle braking control method based on the desired path point elevation, the method comprising the following steps: S1. Obtain the desired path point set and the vehicle's current position coordinates; where each path point in the desired path point set contains three-dimensional coordinate information, including planar position coordinates and elevation coordinates.

[0027] Specifically, the desired pathpoint set can be obtained from the preset driving route of the autonomous vehicle. These desired pathpoints are GPS positioning points, each containing three-dimensional coordinate information: planar position coordinates (longitude and latitude) and elevation coordinates (altitude). The X-coordinate (longitude), Y-coordinate (latitude), and Z-coordinate (elevation, in meters, representing the pathpoint's height relative to sea level) are used. The density of the pathpoints can be set according to actual needs, preferably one pathpoint every 1-5 meters to ensure the continuity and accuracy of elevation information. All pathpoints are arranged sequentially according to the driving order, forming a complete driving path elevation dataset. The vehicle's current position data can be obtained in real-time through devices such as the vehicle's GPS positioning module and inertial measurement unit (IMU), acquiring the vehicle's current three-dimensional position coordinates. ,in, For the current longitude, For the current latitude, This provides the current elevation. Additionally, it acquires auxiliary parameters such as the vehicle's current speed V (unit: km / h) and direction of travel, which are used for subsequent path point matching and control compensation adjustment.

[0028] S2. Based on the vehicle's current location coordinates, match the nearest point of the vehicle in the desired path point set.

[0029] Specifically, in some embodiments of the present invention, matching the nearest point of a vehicle in the desired path point set may include: Calculate the horizontal distance between the vehicle's current position coordinates and each desired path point; Select the desired path point with the smallest horizontal distance as the candidate nearest point; If there are multiple candidate closest points with equal and minimum horizontal distances, the candidate closest point located in front of the vehicle's direction of travel is selected as the closest point.

[0030] For example, a distance calculation algorithm can be used to calculate the vehicle's current position. With each path point in the desired path point set The planar distance between them is calculated using the following formula: , Let be the horizontal distance between the current vehicle and the i-th path point. , Let be the longitude and latitude of the i-th path point. It should be noted that elevation differences can be ignored during calculation; only the horizontal distance corresponding to longitude and latitude is calculated to avoid interference from elevation in the nearest point matching. Next, traverse all path points. Value, select The smallest path point is taken as the "closest point on the path to the vehicle's current location", denoted as . Its coordinates are If there are multiple path points If the values ​​are equal and both are the minimum, then the path point ahead in the direction of travel is selected as the nearest point. (Ensure that the matched path points match the vehicle's driving trend).

[0031] S3. Using the nearest point as a reference, select path points within a preset distance range before and after the nearest point from the desired path point set to form an elevation fitting sample set. The preset distance range is 5-20 meters, and this range is dynamically adjusted based on the vehicle's current speed.

[0032] Specifically, taking the nearest point Based on this, select a distance along the vehicle's direction of travel (the positive direction of the path points). For all desired path points within a range of X meters ahead, simultaneously select distances along the opposite direction of vehicle travel (the opposite direction of the path point arrangement). For all desired path points within a range of X meters behind, the selected forward and backward path points will be compared with the nearest point. Together, these form the set of path points for elevation fitting. For example, based on the spacing between path points, the number of path points within a range of X meters can be calculated. Assuming the spacing between path points is 2 meters and X = 10 meters, then 5 path points are selected ahead (distance...). (Points 2-10 meters apart), then select 5 path points (distances from each other). (2-10 meters), plus A total of 11 path points are used to form the fitting set. If the number of path points within an X-meter range is insufficient, all remaining path points in that direction are selected (e.g., if the vehicle travels to the vicinity of the path start and there are no path points behind it, only path points within an X-meter range ahead are selected). (Form the fitted set).

[0033] Next, the selected set of elevation fitting path points can be deduplicated to ensure that each path point participates in the fitting calculation only once, and the coordinate information of each fitted path point can be recorded. and the path point and the nearest point The horizontal distance L between them (unit: meters, L is positive for forward path points and negative for backward path points). L is set to 0), which is used for subsequent elevation fitting.

[0034] S4. Perform linear fitting on the elevation and horizontal distance of each path point in the elevation fitting sample set to obtain the fitting function and the slope K representing the slope.

[0035] Specifically, in some embodiments of the present invention, linear fitting of the elevation and horizontal distance of each path point in the elevation fitting sample set may include: Linear fitting was performed using the least squares method, and the fitting function was: Z = KL + B; Where L is the horizontal distance of each path point in the elevation fitting sample set relative to the nearest point, with the direction in front of the vehicle being positive and the direction behind being negative; Z is the elevation of the corresponding path point; K is the slope of the fitted line, used to characterize the magnitude and direction of the slope; and B is the intercept of the fitted line, corresponding to the elevation of the nearest point.

[0036] For example, fitting path points and The horizontal distance L is used as the independent variable (horizontal axis), and the elevation Z of the fitted path points is used as the dependent variable (vertical axis). The least squares method is used to linearly fit the (L, Z) data of the elevation fitting path point set, resulting in a linear function of elevation change. The fitted function expression is: Z = KL + B, where K is the slope of the function (i.e., the slope of the fitted road segment; the larger the K value, the steeper the uphill slope; the smaller the K value, the steeper the downhill slope), and B is the intercept (i.e., the closest point). elevation Because when L=0, ).

[0037] The specific calculation process of least squares fitting: Let the set of fitting path points have a total of n points, which are ( , ), ( , ), ..., ( , The slope K and intercept B are calculated using the following formulas: ; ; in, for to The average value of is to The average value of , .

[0038] S5. According to the comparison result between the slope K and the preset slope threshold, determine the slope section types of the current section and the section ahead; Specifically, in some embodiments of the present invention, the preset slope threshold includes an uphill threshold K1 and a downhill threshold K2, and K1 > K2; according to the comparison result between the slope K and the preset slope threshold, determining the slope section types of the current section and the section ahead specifically includes: if K > K1, it is determined as an uphill section; if K < K2, it is determined as a downhill section; if K2 ≤ K ≤ K1, it is determined as a flat section.

[0039] For example, the uphill threshold K1 is preferably 0.05, and the downhill threshold K2 is preferably -0.05. Compare the fitted slope K with the previously preset slope judgment threshold to determine the types of the current and upcoming sections of the vehicle: When K > (i.e., K > 0.05), it is determined as an uphill section, and the larger the K value, the steeper the uphill slope; When K < (i.e., K < -0.05), it is determined as a downhill section, and the smaller the K value (the larger the absolute value), the steeper the downhill slope; When ≤ K ≤ (i.e., -0.05 ≤ K ≤ 0.05), it is determined as a flat section, that is, the elevation change of the section is gentle and no slope section compensation is required.

[0040] S6. According to the slope section type, perform active compensation control on the throttle or brake of the vehicle to keep the vehicle speed stable.

[0041] Specifically, in some embodiments of the present invention, according to the slope section type, performing active compensation control on the throttle or brake of the vehicle specifically includes: when it is determined as an uphill section, perform throttle compensation control, and the throttle compensation amplitude is positively correlated with the magnitude of the slope K; when it is determined as a downhill section, perform brake compensation control, and the brake compensation amplitude is positively correlated with the absolute value of the slope K; when it is determined as a flat section, no throttle or brake compensation is performed, and the conventional constant speed control mode is maintained.

[0042] For example, according to the section type determined in step S5, combined with the current driving speed V of the vehicle, perform corresponding compensation on the throttle opening or brake pressure of the vehicle according to the preset compensation strategy to achieve stable vehicle speed control. The compensation logic is as follows: 1) Compensation for uphill sections (K> When going uphill, the vehicle is affected by the component of gravity, which can easily cause a decrease in speed. In this case, throttle compensation is applied by increasing the throttle opening to supplement driving force and maintain stable speed. The compensation amount is positively correlated with the slope K; that is, the larger the K value (the steeper the uphill slope), the greater the throttle opening compensation. The specific compensation formula can be preset as follows: ,in, Throttle opening compensation amount (unit: %) Set a basic compensation coefficient (which can be adjusted according to the vehicle's power parameters, with a preferred value of 5-10); at the same time, set an upper limit for throttle opening compensation (for example, the maximum compensation amount should not exceed 20%) to avoid excessive throttle leading to excessive vehicle speed.

[0043] 2) Compensation for downhill sections (K< When going downhill, vehicles are affected by the component of gravity, which can easily cause their speed to increase. Braking compensation is then applied, using appropriate braking pressure to suppress this increase and maintain a stable speed. The compensation amount is positively correlated with the absolute value of the slope K; that is, the smaller the K value (the steeper the downhill slope), the greater the braking pressure compensation. The specific compensation formula can be preset as follows: ,in, Braking pressure compensation (unit: MPa). Set a base braking coefficient (which can be adjusted according to the vehicle's braking parameters, with a preferred value of 0.1-0.3); at the same time, set an upper limit for braking pressure compensation (for example, the maximum compensation amount should not exceed 1.0MPa) to avoid excessive braking that could cause a sudden drop in vehicle speed or wheel lock-up.

[0044] 3) Control of flat road sections ( ≤K≤ ): No throttle or brake compensation is required. The vehicle can maintain a constant speed by adjusting the throttle opening or brake pressure normally according to the target speed preset by the autonomous driving system.

[0045] In some embodiments of the present invention, the active compensation control of throttle or brake is provided with a compensation upper limit to prevent over-compensation and ensure driving safety.

[0046] In some embodiments of the present invention, the control cycle of the method is 0.1 seconds to 0.5 seconds. In each control cycle, the current position of the vehicle is updated in real time, the nearest point is rematched, the slope K is recalculated and the compensation amount is updated to form a closed-loop control.

[0047] In some embodiments of the present invention, a fault handling mechanism may also be included: when a GPS signal interruption or abnormal elevation data is detected, the system automatically switches to a backup planar path control mode, which is a mode that controls the throttle and brakes based solely on planar position coordinates and vehicle status parameters.

[0048] It is understood that this invention constructs a complete closed-loop control system and designs a robust anomaly handling mechanism to ensure the continuity of the control process and the reliability of the system. Specifically, within each control cycle, the system updates the vehicle position and waypoint data in real time, re-matches the nearest point, selects fitting samples, performs elevation fitting and slope judgment, and adjusts the compensation amount to ensure that the control strategy remains synchronized with the vehicle's driving state and path changes. If the desired path changes during driving (e.g., the autonomous driving system replans the path), the system immediately updates the waypoint set and re-executes all steps to ensure that the control method matches the new path in real time. Corresponding protections are implemented for different anomaly situations: when the GPS signal is interrupted, it temporarily switches to the traditional planar path control mode to maintain basic driving functions. When elevation data is abnormal, abnormal points are automatically removed or the system switches to a backup mode.

[0049] Therefore, once the signal and data return to normal, the system seamlessly switches back to the control mode of this invention. This mechanism effectively avoids the risks of control interruption and loss of control, ensuring the continuity, reliability, and safety of throttle and brake control during autonomous driving, providing a solid guarantee for practical engineering applications. Example

[0050] Scenario: Level 2 autonomous sightseeing vehicle, driving on undulating roads in the scenic area (including alternating uphill, downhill, and flat sections), with a target speed of 8~15km / h, a desired path point spacing of 2 meters, a GPS positioning accuracy of ±0.1 meters, and an elevation measurement accuracy of ±0.2 meters.

[0051] Preset parameters: Path point selection range X = 10 meters, uphill threshold K1 = 0.05, downhill threshold K2 = -0.05, throttle base compensation coefficient. Braking base compensation coefficient Throttle compensation limit is 20%, brake compensation limit is 1.0MPa, and control cycle is 0.2 seconds.

[0052] Implementation process: Step 1: Preliminary Preparation: Obtain the desired set of path points for this mountainous road section. Each path point contains XYZ coordinates (e.g., ...). Point: X = 116.3°, Y = 39.9°, Z = 150.0 meters; Point: X = 116.30002°, Y = 39.90001°, Z = 150.2 meters; Points: X=116.29998°, Y=39.89999°, Z=149.8 meters, and so on); the vehicle's current location A (X0=116.3°, Y0=39.9°, Z0=150.1 meters) and current speed V=10km / h are obtained in real time through the vehicle's GPS and IMU devices.

[0053] Step 2, Nearest Point Matching: Calculate the horizontal distance between the vehicle's current position A and all desired path points. It is found that the horizontal distance between A and point P0 is the smallest (di = 0.2 meters), thus determining the closest point. It is the closest point.

[0054] Step 3: Selection of Fitting Path Points: Based on this, there are 5 waypoints within a 10-meter radius ahead. - The area within 10 meters behind contains 5 waypoints. - ), plus There are 11 path points in total, forming a fitting set; the relationship between each path point and the fitted set is recorded. Horizontal distance L ( L = 2 meters L = 4 meters, ... L = 10 meters; L = -2 meters L = -4 meters, ... L = -10 meters; (L=0 meters) and elevation Z.

[0055] Step 4: Elevation Fitting and Slope Judgment: The least squares method is used to fit the (L, Z) data of 11 path points, and the fitting function is obtained as Z=0.08L+150.0, that is, the slope K=0.08 and the intercept B=150.0 (consistent with the point elevation in Step 3); since K=0.08>K1=0.05, it is determined to be an uphill section with a moderate slope.

[0056] Step 5, Throttle compensation execution: According to the compensation formula Δα=α0×(K-K1=8×(0.08-0.05)=0.24%, that is, the throttle opening is compensated by 0.24%. The current base value of the throttle opening is 15%, and the throttle opening after compensation is 15.24%, which supplements the driving force and maintains the vehicle speed.

[0057] Step Six: Closed-Loop Update: Repeat the above steps every 0.2 seconds. When the vehicle reaches the next control cycle, rematch the nearest point as P1, select the path points 10 meters before and after P1 for fitting, and obtain K=0.09. Adjust the compensation amount to 0.32% and maintain the vehicle speed. When driving on flat road, the fitting result is K=0.03, which is between K1 and K2. Stop compensation and drive at a normal constant speed. When driving on downhill road, the fitting result is K=-0.07. Braking compensation ΔP=0.2×(-0.05 - (-0.07))=0.004MPa. Apply slight braking to suppress the increase in vehicle speed.

[0058] Implementation results: When driving on undulating road sections, the vehicle speed fluctuation range is controlled within ±1.5km / h, with no obvious sudden increase or decrease in speed; compared with existing technologies, the frequency of throttle-brake switching is reduced, vehicle energy consumption is reduced, brake system wear is reduced, and the driving experience and safety are significantly improved.

[0059] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. An automatic driving throttle braking control method based on the elevation of desired path points, characterized in that, Includes the following steps: S1. Obtain the desired path point set and the vehicle's current position coordinates; wherein, each path point in the desired path point set contains three-dimensional coordinate information, including planar position coordinates and elevation coordinates; S2. Based on the vehicle's current position coordinates, match the nearest point of the vehicle in the desired path point set; S3. Using the nearest point as a reference, select path points located within a preset distance range before and after the nearest point from the expected path point set to form an elevation fitting sample set; S4. Perform linear fitting on the elevation and horizontal distance of each path point in the elevation fitting sample set to obtain the fitting function and the slope K representing the slope. S5. Based on the comparison result between the slope K and the preset slope threshold, determine the slope type of the current road segment and the road segment ahead. S6. Based on the type of slope, actively compensate and control the vehicle's throttle or brakes to keep the vehicle speed stable.

2. The method for automatic throttle and braking control based on the desired path point elevation according to claim 1, characterized in that, The planar position coordinates are longitude and latitude, and the elevation coordinates are altitude; the preset distance range is 5-20 meters, and the preset distance range is dynamically adjusted according to the vehicle's current driving speed.

3. The method for automatic throttle and braking control based on the desired path point elevation according to claim 1, characterized in that, The matching of the nearest point of the vehicle in the desired path point set specifically includes: Calculate the horizontal distance between the vehicle's current position coordinates and each desired path point; Select the desired path point with the smallest horizontal distance as the candidate nearest point; If there are multiple candidate closest points with equal and minimum horizontal distances, the candidate closest point located in front of the vehicle's direction of travel is selected as the closest point.

4. The method for automatic throttle and braking control based on the desired path point elevation according to claim 1, characterized in that, The linear fitting of the elevation and horizontal distance of each path point in the elevation fitting sample set specifically includes: Linear fitting is performed using the least squares method, and the fitting function is: Z = KL + B; Where L is the horizontal distance of each path point in the elevation fitting sample set relative to the nearest point, with the direction in front of the vehicle being positive and the direction behind being negative; Z is the elevation of the corresponding path point; K is the slope of the fitted straight line, used to characterize the magnitude and direction of the slope; and B is the intercept of the fitted straight line, corresponding to the elevation of the nearest point.

5. The method for automatic throttle and braking control based on the desired path point elevation according to claim 1, characterized in that, The preset slope thresholds include an uphill threshold K1 and a downhill threshold K2, and K1 > K2; The step of determining the slope type of the current road segment and the road segment ahead based on the comparison result of the slope K and the preset slope threshold specifically includes: If K > K1, then it is determined to be an uphill section; If K < K2, then it is determined to be a downhill section; If K2 ≤ K ≤ K1, then it is determined to be a straight road section.

6. The method for automatic throttle and brake control based on the desired path point elevation according to claim 5, characterized in that, The uphill threshold K1 is preferably 0.05, and the downhill threshold K2 is preferably -0.

05.

7. The method for automatic throttle and braking control based on the desired path point elevation according to claim 5, characterized in that, The active compensation control of the vehicle's throttle or brakes based on the slope type specifically includes: When the road is determined to be uphill, throttle compensation control is executed, and the throttle compensation magnitude is positively correlated with the slope K. When the road is determined to be downhill, braking compensation control is executed, and the braking compensation magnitude is positively correlated with the absolute value of the slope K. When the road is determined to be a straight section, no throttle or brake compensation is applied, and the normal constant speed control mode is maintained.

8. The method for automatic throttle braking control based on the desired path point elevation according to claim 1 or 7, characterized in that, The active compensation control for throttle or brake is set with a compensation upper limit to prevent overcompensation and ensure driving safety.

9. The method for automatic throttle and braking control based on the desired path point elevation according to claim 1, characterized in that, The control cycle of the method is 0.1 to 0.5 seconds. In each control cycle, the current position of the vehicle is updated in real time, the nearest point is rematched, the slope K is recalculated and the compensation amount is updated to form a closed-loop control.

10. The method for automatic throttle and braking control based on the desired path point elevation according to claim 1, characterized in that, It also includes fault handling mechanisms: When a GPS signal interruption or abnormal elevation data is detected, the system automatically switches to the backup horizontal path control mode, which is a mode that controls the throttle and brakes based solely on the horizontal position coordinates and vehicle status parameters.

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