Longitudinal control method and device for shifting gear in advance during parking, vehicle and medium

Abstract

The invention relates to the technical field of vehicle control, and discloses a longitudinal control method and device for gear shifting in advance in parking, a vehicle and a medium, and the method comprises the steps that vehicle information, current single-step path environment information and next single-step path environment information are obtained; according to the vehicle information and the current single-step path environment information, the advanced gear shifting position of the vehicle running on the current single-step path is determined; according to the vehicle information and the current single-step path environment information, a first motor torque before the advanced gear shifting position is output; and the second motor torque after the advanced gear shifting position is output according to the vehicle information and the next single-step path environment information. According to the method, the stability of the whole vehicle controlled by shifting gears in advance is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of vehicle control, in particular to a longitudinal control method and device for early gear shifting in parking, a vehicle and a medium. BACKGROUND

[0002] With the continuous rapid development of intelligent driving technology, the automatic parking assist system (APA) as one of the key functions of L2 level automatic driving technology plays a decisive role in improving the user driving experience. Since new energy vehicles can realize forward and reverse switching by changing the forward and reverse rotation of the motor, they do not need to rely on other mechanical structures. Therefore, compared with the restriction that the fuel vehicle must be stopped before the forward / reverse gear shifting, the new energy vehicle can realize forward / reverse gear shifting during vehicle driving. The application of this technology in the APA technology can significantly improve the parking efficiency. At present, the electric vehicle early gear shifting scheme provided by the related technology is to control the vehicle to perform reverse gear shifting by braking before the vehicle speed is reduced to 0kph. After the vehicle performs gear shifting, the motor switching direction torque is increased, so as to achieve the effect of deceleration and reverse acceleration by relying on the superposition of motor torque, instead of relying only on the braking system for deceleration, so that the automatic parking process is more smooth and the automatic parking is more time-saving. However, the related technology still has some problems difficult to solve, and often in the early gear shifting control strategy, the torque requested by the previous path is not reasonable for the next path, which increases the control difficulty of the next path and makes the vehicle unstable. SUMMARY

[0003] The present application provides a longitudinal control method, device, vehicle and medium for early gear shifting in parking to solve the problem of unstable vehicle control in early gear shifting.

[0004] In a first aspect, the present application provides a longitudinal control method for early gear shifting in parking, which comprises: obtaining vehicle information, current single-step path environment information and next single-step path environment information; determining an early gear shifting position of the vehicle on the current single-step path according to the vehicle information and the current single-step path environment information; outputting a first motor torque before the early gear shifting position according to the vehicle information and the current single-step path environment information, the first motor torque being used to control the vehicle to travel on the current single-step path before gear shifting; and outputting a second motor torque after the early gear shifting position according to the vehicle information and the next single-step path environment information, the second motor torque being used to control the vehicle to travel on the current single-step path after gear shifting.

[0005] According to the above technical means, by acquiring multi-dimensional information and outputting motor torque in stages, the problem of mismatch between traditional pre-shift torque request and path is solved from the core logic. By separately calculating the first and second motor torques before and after shifting, it is ensured that the torque before shifting meets the current path driving demand, and the torque after shifting accurately matches the next path environment, avoiding speed overshoot, sudden braking or jerk caused by unreasonable torque. At the same time, the shift position is determined in advance to realize stable shifting without stopping, greatly shortening the switching time between two parking path segments, balancing parking efficiency and driving smoothness, and improving the safety and driving experience of automatic parking.

[0006] In some optional embodiments, before determining the pre-shift position of the vehicle on the current single-step path according to the vehicle information and the current single-step path environment information, the method further comprises: determining whether the pre-shift condition is met according to the vehicle information and the current single-step path environment information; when the pre-shift condition is met, performing the step of determining the pre-shift position of the vehicle on the current single-step path according to the vehicle information and the current single-step path environment information.

[0007] According to the above technical means, the pre-shift condition is added to avoid the risk of pre-shift in unreasonable scenarios. Through the pre-condition screening, the problems of motor zero-crossing jerk, sliding too far, path deviation, etc. caused by shifting in scenarios such as too short single-step path, too fast vehicle speed, and too large slope are avoided. Only when the safety and smoothness are met, pre-shift is performed, which not only guarantees the stability of the parking process, but also ensures the effective play of the technical advantages of pre-shift, further improving the reliability and practicality of the control method.

[0008] In some optional embodiments, determining whether the pre-shift condition is met according to the vehicle information and the current single-step path environment information comprises: determining whether the single-step path length is greater than a preset distance threshold according to the current single-step path environment information; when the single-step path length is greater than the preset distance threshold, determining whether the distance between the vehicle and the obstacle is greater than a preset distance threshold according to the current single-step path environment information; when the distance between the vehicle and the obstacle is greater than the preset distance threshold, determining whether the actual vehicle speed before shifting is less than a preset speed threshold according to the vehicle information; when the actual vehicle speed before shifting is less than the preset speed threshold, determining whether the absolute value of the road slope percentage is less than a preset slope percentage according to the current single-step path environment information; when the absolute value of the road slope percentage is less than the preset slope percentage, determining whether the lateral error of the vehicle is less than the corresponding preset error threshold; when the lateral error is less than the corresponding preset error threshold, determining that the pre-shift condition is met.

[0009] According to the above technical means, the multi-dimensional judgment standard of early gear shifting is refined, and the key factors affecting the safety and smoothness of gear shifting are comprehensively covered through comprehensive verification of single-step path length, obstacle distance, vehicle speed, slope, and lateral error. The specific problems such as short path torque shifting, close distance without brake protection, high vehicle speed sliding, large slope jerk, and large lateral deviation are avoided, ensuring that early gear shifting is triggered only in the optimal scenario, maximizing the reduction of safety risks, while ensuring driving comfort and parking accuracy.

[0010] In some optional embodiments, determining the early gear shifting position of the vehicle driving on the current single-step path according to the vehicle information and the current single-step path environment information comprises: calculating the gear shifting distance from the starting point of the current single-step path based on the actual vehicle speed before gear shifting, the single-step path length, and the road slope, and determining the early gear shifting position according to the gear shifting distance.

[0011] According to the above technical means, the core parameters of vehicle speed, path length, and slope are integrated to realize accurate quantization of the gear shifting position. Compared with the traditional experience-based gear shifting position selection, this calculation method can adapt to different parking scenarios and avoid problems caused by early or late gear shifting, ensuring sufficient distance to reduce torque and smooth gear shifting, and preventing gear shifting from being too late to lose the efficiency advantage of early gear shifting. The accurate gear shifting position lays a foundation for subsequent torque and brake collaborative control, further improving the smoothness and controllability of the parking process.

[0012] In some optional embodiments, based on the actual vehicle speed before gear shifting, the single-step path length, the road slope, and the calculated gear shifting distance from the starting point of the current single-step path, the gear shifting distance comprises: calculating the gear shifting theoretical distance through the ratio of the actual vehicle speed before gear shifting and the comfortable brake deceleration; calculating the first distance for reducing the gear shifting theoretical distance through the single-step path length and the distance conversion coefficient; calculating the second distance for reducing the gear shifting theoretical distance through the road slope and the slope conversion coefficient; and determining the gear shifting distance through the difference between the gear shifting theoretical distance, the first distance, and the second distance.

[0013] According to the above technical means, the theoretical distance of gear shifting is calculated based on the vehicle speed, and the path length and slope are corrected accordingly, avoiding jerk in short path torque shifting and solving the problem of too long sliding distance after gear shifting on a slope. The conversion logic calibrated by the real vehicle ensures that the gear shifting distance is highly matched with the actual scenario, allowing the gear shifting action to maximize efficiency while considering safety and comfort, and improving the scene adaptation ability of the control method.

[0014] In some optional embodiments, the first motor torque before the advance gear shifting position is output according to the vehicle information and the current single-step path environment information, comprising: determining a first target control distance based on a smaller value of a first expected moving distance and an obstacle safety distance, the first expected moving distance being a distance from the vehicle to an end point of the current single-step path, and the obstacle safety distance being a distance in which the vehicle does not collide with an obstacle within a control time; calculating a first theoretical target control vehicle speed through the first target control distance; determining an actual target control vehicle speed before gear shifting based on a product of a first scaling coefficient and the first theoretical target control vehicle speed, the first scaling coefficient being positively correlated with a remaining moving distance of the current single-step path; calculating an acceleration stage target acceleration before gear shifting through an error between an actual vehicle acceleration and the actual target control vehicle speed before gear shifting, and calculating a deceleration stage target acceleration before gear shifting through the first target control distance; and calculating the first motor torque through a deviation between the actual vehicle acceleration and a first target acceleration, the first target acceleration being the acceleration stage target acceleration before gear shifting or the deceleration stage target acceleration before gear shifting.

[0015] According to the above technical means, the calculation logic of the first motor torque before gear shifting is provided, and through accurate definition of the target control distance and phased acceleration calculation, the rationality of the torque output before gear shifting is ensured. The target vehicle speed is dynamically adjusted in combination with the remaining moving distance, the actual target control vehicle speed before gear shifting is determined based on a product of the first scaling coefficient and the first theoretical target control vehicle speed, the influence of the brake intervention before the vehicle reaches the end point of the path is reduced, and the problem of body jerk and shaking caused by brake pressure building before gear shifting and pressure relief after gear shifting is solved. The first motor torque is calculated through the optimized actual target control vehicle speed, and the driving smoothness before gear shifting is improved.

[0016] In some optional embodiments, the first traction force is calculated through a deviation between the actual vehicle acceleration and the first target acceleration; the friction compensation force, the wind resistance compensation force and the slope compensation force are obtained; the total vehicle driving force is determined based on a sum of the first traction force, the friction compensation force, the wind resistance compensation force and the slope compensation force; and the first motor torque is calculated through the total vehicle driving force.

[0017] According to the above technical means, through the superposition calculation of the traction torque and various compensation torques, the interference factors such as friction and slope are effectively offset, the vehicle maintains a stable driving state before gear shifting, good preparation is made for the subsequent advance gear shifting, and the driving smoothness before gear shifting is improved.

[0018] In some optional embodiments, outputting the second motor torque after the pre-shift position according to the vehicle information and the next single-step path environment information comprises: determining a second target control distance based on a smaller value of a second expected moving distance and an obstacle safety distance, the second expected moving distance being a distance from the vehicle to an end point of the next single-step path, and the obstacle safety distance being a distance at which the vehicle does not collide with an obstacle within a control time; calculating a second theoretical target control vehicle speed through the second target control distance; determining an actual target control vehicle speed after shifting based on a product of a second scaling coefficient and the second theoretical target control vehicle speed, the second scaling coefficient being positively correlated with a remaining moving distance of the next single-step path, and the second scaling coefficient being 1 if the next single-step path does not require pre-shifting; calculating a target acceleration in an acceleration phase after shifting through an error between the actual vehicle speed after shifting and the actual target control vehicle speed after shifting, and calculating a target acceleration in a deceleration phase after shifting through the second target control distance; calculating the second motor torque through a PI control algorithm based on a deviation between the actual vehicle acceleration and a second target acceleration, the second target acceleration being the target acceleration in the acceleration phase after shifting or the target acceleration in the deceleration phase after shifting, an actual rising step of the second motor torque being configured to be greater than a default step, a proportional coefficient in the PI control algorithm being increased through an amplification coefficient, and an integral coefficient in the PI control algorithm being increased or decreased through a reduction coefficient, the amplification coefficient being positively correlated with a target vehicle speed of the next single-step path, the reduction coefficient being positively correlated with the target vehicle speed of the next single-step path, and the target vehicle speed of the next single-step path being determined based on the next single-step path environment information.

[0019] According to the above technical means, the calculation logic of the second motor torque after shifting is optimized, and the control parameters are dynamically adjusted in combination with the next path information. The proportional coefficient and the integral coefficient of the PI algorithm are adjusted to solve the overshoot problem caused by the large torque of the traditional PI control in the reverse phase of the vehicle speed after shifting. The torque rising step is increased to ensure that the vehicle quickly adjusts the driving direction and avoids sliding too far. This design precisely matches the torque demand of the next path after shifting, balances the starting efficiency and driving smoothness, and completely solves the core pain point of unreasonable torque connection between two paths.

[0020] In some optional embodiments, the second motor torque is calculated through a PI control algorithm based on a deviation between the actual vehicle acceleration and the target acceleration in the deceleration phase, comprising: the second traction force is calculated through a PI control algorithm based on a deviation between the actual vehicle acceleration and the target acceleration in the deceleration phase; the friction compensation force, the wind resistance compensation force, and the slope compensation force are obtained; the vehicle driving force is determined based on a difference between the first torque force and the second torque force, the first torque force being a sum of the second traction force and the slope compensation force, and the second torque force being a sum of the friction compensation force and the wind resistance compensation force; and the second motor torque is calculated through the vehicle driving force.

[0021] According to the above technical means, the torque calculation is refined in the deceleration stage after shifting, and the special state that the vehicle moving direction is opposite to the gear is adapted through the difference calculation of the traction torque and the compensation torque. The corrected torque calculation logic can effectively offset the interference of friction and wind resistance on the reverse deceleration, ensure that the vehicle quickly and smoothly reduces the vehicle speed to 0 and switches the driving direction, avoid the sliding too far caused by insufficient torque in the deceleration stage, or the jerk caused by excessive torque, improve the controllability and smoothness of the deceleration process after shifting, and ensure the safety of the close-range parking scene.

[0022] In some optional embodiments, the method further comprises: increasing the coasting distance threshold for triggering the coasting brake protection strategy after shifting; providing an additional requested torque if the moving distance of the vehicle after shifting is greater than the preset sliding distance threshold; and canceling the acceleration rising step constraint of the vehicle after shifting.

[0023] According to the above technical means, the three supplementary strategies are further optimized for post-shifting control, which comprehensively covers the special scene requirements after shifting. Increasing the coasting distance threshold avoids the false triggering of the anti-coasting strategy, ensuring the normal parking process; providing an additional requested torque prevents the vehicle from sliding too far, improving safety; and canceling the acceleration rising step constraint solves the slow starting problem, improving efficiency. The three strategies optimize from the three dimensions of process continuity, safety protection, and starting performance, effectively making up for the details of the basic control logic, making the post-shifting control more comprehensive and accurate, and further improving the parking experience.

[0024] In some optional embodiments, before outputting the second motor torque after the early shifting position according to the vehicle information and the next single-step path environment information, the method further comprises: adjusting the motor torque to 0 when shifting; if the scene is switched from flat road or uphill to downhill when shifting, linearly increasing the brake force through the brake actuator until the downhill acceleration stabilizes when entering the downhill, wherein the slope of the linearly increasing brake force is positively correlated with the slope change; if the scene is switched from downhill to flat road or uphill when shifting, linearly decreasing the brake force through the brake actuator until the brake pressure is reduced to 0.

[0025] According to the above technical means, the key control at the shifting moment is focused on, and the core jerk problem in traditional shifting is solved through torque zeroing and scenario-based brake pressure adjustment. The torque is reduced to 0 when shifting to avoid the motor impact caused by torque shifting, and the brake pressure is pre-built when shifting from flat road / uphill to downhill and pre-released when shifting from downhill to flat road / uphill, achieving smooth transition of the brake pressure. This design completely eliminates the body shaking caused by brake pressure building and releasing before and after shifting, making the shifting action smoother, and adapting to the brake demand of the slope scene, improving the stability and comfort of early shifting in different road conditions.

[0026] In a second aspect, the present application provides a longitudinal control device for early gear shifting in parking, comprising: an information acquisition module, configured to acquire vehicle information, current single-step path environment information and next single-step path environment information; a gear shifting position determination module, configured to determine an early gear shifting position of the vehicle on the current single-step path according to the vehicle information and the current single-step path environment information; a pre-gear shifting control module, configured to output a first motor torque before the early gear shifting position according to the vehicle information and the current single-step path environment information, the first motor torque being used to control the vehicle to travel on the current single-step path before gear shifting; and a post-gear shifting control module, configured to output a second motor torque after the early gear shifting position according to the vehicle information and the next single-step path environment information, the second motor torque being used to control the vehicle to travel on the current single-step path after gear shifting.

[0027] In a third aspect, the present application provides a vehicle, comprising: a memory and a processor, which are communicatively connected with each other, and the memory stores computer instructions, and the processor executes the computer instructions to perform the method of the first aspect or any of the corresponding embodiments thereof.

[0028] In a fourth aspect, the present application provides a computer readable storage medium, which stores computer instructions, and the computer instructions are used to make a computer execute the method of the first aspect or any of the corresponding embodiments thereof.

[0029] In a fifth aspect, the present application provides a computer program product, which comprises computer instructions, and the computer instructions are used to make a computer execute the method of the first aspect or any of the corresponding embodiments thereof. BRIEF DESCRIPTION OF DRAWINGS

[0030] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the drawings needed to be used in the specific embodiments or the prior art description. Obviously, the drawings described below are some embodiments of the present application, and those skilled in the art can obtain other drawings according to these drawings without creative labor.

[0031] Figure 1 is a first flowchart of a longitudinal control method for early gear shifting in parking according to an embodiment of the present application; Figure 2 is a second flowchart of a longitudinal control method for early gear shifting in parking according to an embodiment of the present application; Figure 3 is a third flowchart of a longitudinal control method for early gear shifting in parking according to an embodiment of the present application; Figure 4Fig. 4 is a fourth flowchart illustrating a method for longitudinal control of early shift in parking according to an embodiment of the present application; Figure 5 Fig. 5 is a fifth flowchart illustrating a method for longitudinal control of early shift in parking according to an embodiment of the present application; Figure 6 Fig. 6 is a structural block diagram of a longitudinal control device for early shift in parking according to an embodiment of the present application; Figure 7 Fig. 7 is a hardware structure diagram of an electronic device according to an embodiment of the present application. DETAILED DESCRIPTION

[0032] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0033] It can be understood that, before using the technical solutions disclosed in the embodiments of the present application, the type, use range, use scenario and the like of personal information involved in the present application should be informed to the user and the authorization of the user should be obtained through appropriate means according to relevant laws and regulations.

[0034] The terms "first", "second" are only used for descriptive purpose, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more than two, unless otherwise specifically limited.

[0035] The embodiments of the present application will be described below with reference to the drawings.

[0036] With the continuous rapid development of intelligent driving technology, the automatic parking assist system (APA) as one of the key functions of L2 level automatic driving technology plays a decisive role in improving the user driving experience. Since new energy vehicles can realize forward and reverse switching by changing the positive and negative rotation of the motor, they do not need to rely on other mechanical structures. Therefore, compared with the restriction that the fuel vehicle must be stopped before the forward / reverse gear shifting, the new energy vehicle can realize forward / reverse gear shifting during vehicle driving. The application of this technology in the APA technology can significantly improve the parking efficiency. At present, the electric vehicle pre-shift scheme provided by the related technology is to control the vehicle to perform reverse gear shifting before the vehicle speed is reduced to 0 kph by braking, and after the vehicle performs gear shifting, the motor switching direction torque is increased, so as to achieve the effect of relying on the superposition of motor torque for deceleration and reverse acceleration, instead of relying only on the braking system for deceleration, so that the automatic parking process is more smooth and the automatic parking is more time-saving, but the related technology still has some problems difficult to solve.

[0037] 1. After gear shifting, the related technology still uses the torque control of the current section of the path until the vehicle speed is reduced to 0 by relying on the reverse torque, and then the decision end sends the moving distance of the next section of the path to the control end, and the control end continues to plan the torque of the next section of the path when the vehicle speed is 0. This scheme may cause the requested torque to be unreasonable for the next section of the path during the time from the gear shifting time to receiving the next section of the path, for example, if the length of the next section of the path is short and the requested torque of the current section of the path is large before parking, the vehicle speed overshoots and then brakes urgently when starting the next section of the path, affecting the vehicle stability.

[0038] 2. Before the vehicle pre-shifts, the related technology relies on hydraulic braking, and the control scheme after the shift is often to rely on the reverse torque for speed reduction while reducing the hydraulic braking, which causes the vehicle body to jerk and shake due to the pressure build-up before the shift and the pressure relief after the shift.

[0039] 3. The motor torque after gear shifting is used for the start of the next section of motion, but for the traditional PI control, in the time when the vehicle motion direction is opposite to the vehicle gear (that is, in the time when the vehicle speed is reduced to 0 by relying on the torque after gear shifting), the actual acceleration is negative when the target acceleration is set as normal start, which inevitably causes the requested PI torque component to be larger than the normal start, thereby causing the vehicle speed overshoot after gear shifting and causing subsequent vehicle speed oscillation.

[0040] The above problems can affect the driving comfort and smoothness, and the application designs an automatic parking pre-shift longitudinal control scheme based on the longitudinal control principle, optimizes the torque and brake control request, improves the rationality of the PI torque request, and reduces the brake pressure building before and after the shift, thereby improving the safety and experience comfort of the automatic parking.

[0041] According to the embodiment of the application, a longitudinal control method for parking pre-shift is provided, and it should be noted that the steps shown in the flowchart of the drawings can be executed in a computer system such as a set of computer executable instructions, and although the logical order is shown in the flowchart, in some cases, the steps shown or described herein can be executed in an order different from that shown herein.

[0042] In this embodiment, a longitudinal control method for parking pre-shift is provided, Figure 1 is a flowchart of a longitudinal control method for parking pre-shift according to the embodiment of the application, as Figure 1 shown, the flow includes the following steps: Step S101, obtaining vehicle information, current single-step path environment information and next single-step path environment information; Step S102, determining the pre-shift position of the vehicle driving on the current single-step path according to the vehicle information and the current single-step path environment information; Step S103, outputting a first motor torque before the pre-shift position according to the vehicle information and the current single-step path environment information, the first motor torque being used to control the vehicle driving on the current single-step path before the shift; Step S104, outputting a second motor torque after the pre-shift position according to the vehicle information and the next single-step path environment information, the second motor torque being used to control the vehicle driving on the current single-step path after the shift.

[0043] Specifically, the longitudinal control algorithm for the parking pre-shift technology provided by the application includes three parts in total, which are pre-information acquisition, vehicle motion control and control target output. The pre-information acquisition part mainly processes the input path information and the vehicle self information to obtain the vehicle information, the current single-step path environment information and the next single-step path environment information. The vehicle motion control part plans the control strategy through the information obtained by the pre-information acquisition part, calculates the pre-shift position, the acceleration and deceleration mode and the target vehicle speed in different parking scenarios, obtains the appropriate target acceleration through the vehicle speed deviation, and finally obtains the target torque and the chassis target acceleration through the PI control. The control target output part outputs the request torque, the request deceleration and the target gear position and other information to the corresponding actuators, and finally realizes the motion control of the whole vehicle.

[0044] Therefore, in the parking advance gear shift longitudinal control method of the application, vehicle information, current single-step path environment information and next single-step path environment information are first obtained. The vehicle information refers to key data reflecting the real-time running state of the vehicle, which is mainly obtained through the sensors provided by the vehicle, including but not limited to the current actual speed (unit: km / h) collected by the wheel speed sensor, the road slope (unit: %, positive value indicating uphill, negative value indicating downhill) of the current vehicle position collected by the vehicle acceleration sensor, and the current gear state (such as forward gear, reverse gear) of the vehicle, etc. The current single-step path environment information refers to the environment data related to the single-step driving path currently planned by the vehicle, which is collected by the surround-view camera (realizing 360° environment shooting), ultrasonic radar (detecting close-range obstacles, such as vehicles and road kerbs within a distance of <2m) and angle radar (detecting obstacles in the four corner regions of the vehicle body), and the single-step path length (i.e. the distance from the starting point to the ending point of the current path, unit: m), the relative position and distance (unit: m) between the vehicle and the surrounding obstacles, etc. are obtained after data processing. The next single-step path environment information refers to the environment data of the next planned path to be driven by the vehicle after the current path is completed, which has the same data types as the current single-step path environment information, and is also obtained by collecting and processing the above-mentioned surround-view and radar devices, including the length of the next path, the distribution and distance of obstacles in the next path, etc. The advance acquisition of this information provides data support for the driving control of the vehicle after gear shifting, avoiding the control delay caused by waiting for path information after gear shifting in the traditional scheme.

[0045] After the information acquisition is completed, the vehicle information and the current single-step path environment information are used to determine the advance gear shift position of the vehicle on the current single-step path in the embodiment of the application. The advance gear shift position refers to the specific position (distance value from the starting point of the current path, unit: m) at which the vehicle is shifted in the current single-step path without driving to the end of the path and stopping. When determining the position, the current actual speed and the road slope in the vehicle information, and the single-step path length in the current single-step path environment information are comprehensively considered. For example, if the current actual speed is 3 km / h, the road slope is 1% (gentle uphill), and the current single-step path length is 5 m, the driving distance required from the current position to the gear shift position is calculated in combination with the braking deceleration characteristics of the vehicle under the speed and slope (such as the comfortable braking deceleration of 0.5 m / s²), to ensure that the gear shift position is neither too close to the starting point of the current path (to avoid insufficient subsequent driving distance caused by early gear shifting), nor too close to the end of the current path (to avoid losing the advantage of shortening the time by advance gear shifting), and finally a specific position balancing smoothness and efficiency is determined.

[0046] Afterwards, the vehicle control is divided into two parts before and after shifting by the embodiment of the application, and the first motor torque before the shifting position is output according to the vehicle information and the current single-step path environment information. The first motor torque refers to the power or braking torque (unit: N m) that the driving motor needs to output before the vehicle drives to the shifting position, which functions to control the vehicle to drive smoothly on the current single-step path to the shifting position. When calculating the torque, the current actual vehicle speed, road slope in the vehicle information and single-step path length and obstacle distance in the current single-step path environment information need to be combined. For example, if the current actual vehicle speed is 2.5 km / h, the target is to drive at a constant speed to the shifting position (2 m away from the current position), and the road slope is 0 (flat road), the driving torque needed to offset the resistance is calculated according to the driving resistance of the vehicle, the first motor torque is output, and the vehicle is ensured to drive at a stable speed to the shifting position, avoiding the fluctuation of vehicle speed affecting the shifting smoothness.

[0047] The second motor torque refers to the torque that the driving motor needs to output after the driving motor completes the gear shifting at the shifting position, which is used to control the vehicle to drive on the remaining section of the current single-step path and to prepare for entering the next single-step path. When calculating the torque, the next path length and obstacle distance in the next single-step path environment information and the current actual vehicle speed (real-time vehicle speed after shifting) in the vehicle information need to be combined. For example, the current actual vehicle speed is 2 km / h after shifting, and the next single-step path length is 3 m, the torque that can make the vehicle smoothly transition from the current speed to the required speed of the next path is calculated, if the target speed of the next path is 2.2 km / h (to avoid affecting the efficiency due to too low speed), the appropriate driving torque is output, the vehicle is ensured to drive smoothly after shifting, and the torque output matches the demand of the next path, avoiding the speed overshoot or sudden braking caused by the mismatch between the torque after shifting and the next path in the traditional scheme.

[0048] Through the technical scheme provided by the embodiment of the application, the next single-step path environment information is obtained in advance, breaking the time sequence limitation of waiting for the path information after shifting in the traditional scheme, and avoiding the delay of torque request; at the same time, the first and second motor torques before and after shifting are output in stages, ensuring that the torque before shifting adapts to the driving demand of the current path, and the torque after shifting accurately matches the environment of the next path, fundamentally solving the problems of speed overshoot, sudden braking, jerk and the like caused by the mismatch between the torque and the path in the traditional pre-shifting technology. In addition, the shifting can be completed without stopping the vehicle, greatly shortening the switching time between the two paths, improving the overall efficiency of automatic parking, and at the same time, the smoothness and safety of the driving process are taken into account, effectively improving the automatic parking driving experience of the user.

[0049] In the embodiment, a longitudinal control method for pre-shifting parking is provided,Figure 2 is a flowchart of a longitudinal control method for early shift parking according to an embodiment of the application, as shown in the figure, the flow includes the following steps: Figure 2 In step S201, vehicle information, current single-step path environment information and next single-step path environment information are obtained. For details, please refer to step S101 of the embodiment shown in Figure 1

[0050] In step S202, it is judged whether the early shift condition is met according to the vehicle information and the current single-step path environment information. In step S203, when the early shift condition is met, step S204 is executed.

[0051] Specifically, the embodiment of the application needs to complete the judgment of the early shift condition before early shift, and the judgment process is a key pre-process to ensure the safe and smooth execution of early shift.

[0052] First of all, the "early shift condition" refers to judging whether the early shift can meet the preset standards of "no jerk, no safety risk, no path deviation" based on the real-time state of the vehicle and the current path environment. Only when all judgment dimensions meet the requirements, the shift position can be determined, avoiding problems caused by forced shift in inappropriate scenarios.

[0053] The judgment process needs to call vehicle information and current single-step path environment information synchronously, for example: first, based on the "single-step path length" in the current single-step path environment information, if the single-step path length is too short (such as less than 1.5m), even if the early shift is executed, it will also be difficult to reduce the torque due to the lack of distance, which is easy to cause motor zero jerk, so this scenario does not meet the condition; if the single-step path length meets the requirements, the "vehicle and obstacle distance" in the same environment information is judged; if the obstacle distance is too close (such as less than 1.2m), if the vehicle appears a short sliding during the early shift process, there may be a collision risk, so the obstacle distance needs to be ensured to be safe enough. After the environmental conditions are met, the vehicle information can also be turned to judge: first, the actual vehicle speed before shift is confirmed through the wheel speed sensor data. If the vehicle speed is too high (such as more than 5km / h), the inertia sliding distance of the vehicle after shift will exceed the safe range, and it is difficult to control the speed quickly through torque, so the vehicle speed needs to be in the low speed range.

[0054] The above conditions are only examples and are not limited to this. Only when all the early shift conditions set by the user are met, the current scenario is determined to meet the early shift condition, and then the step of determining the early shift position is executed; if any condition is not met, the early shift process is terminated, and the traditional stop-steady shift mode is switched to ensure parking safety. ​​

[0055] The embodiment of the present application establishes the access threshold from two dimensions of environmental safety (path length, obstacle distance) and vehicle state (vehicle speed, slope), avoids the disadvantages of blindly performing early gear shifting, avoids risks such as short path frustration, close-range collision, high-speed overslip, and downhill coasting, maximizes the reduction of safety hazards while ensuring the advantages of early gear shifting, lays a stable foundation for subsequent precise control of gear shifting position and torque output, and further improves the reliability and driving comfort of automatic parking.

[0056] Step S204, determining the early gear shifting position of the vehicle on the current single-step path according to the vehicle information and the current single-step path environment information. Specifically, please refer to Figure 1 Step S102 of the embodiment shown in the figure, which will not be repeated here.

[0057] Step S205, outputting the first motor torque before the early gear shifting position according to the vehicle information and the current single-step path environment information, the first motor torque being used to control the vehicle to travel on the current single-step path before gear shifting. Specifically, please refer to Figure 1 Step S103 of the embodiment shown in the figure, which will not be repeated here.

[0058] Step S206, outputting the second motor torque after the early gear shifting position according to the vehicle information and the next single-step path environment information, the second motor torque being used to control the vehicle to travel on the current single-step path after gear shifting. Specifically, please refer to Figure 1 Step S104 of the embodiment shown in the figure, which will not be repeated here.

[0059] In some optional embodiments, the above step S202 comprises: Step a1, judging whether the single-step path length is greater than a preset distance threshold according to the current single-step path environment information; Step a2, when the single-step path length is greater than the preset distance threshold, judging whether the distance between the vehicle and the obstacle is greater than a preset distance threshold according to the current single-step path environment information; Step a3, when the distance between the vehicle and the obstacle is greater than the preset distance threshold, judging whether the actual vehicle speed before gear shifting is less than a preset speed threshold according to the vehicle information; Step a4, when the actual vehicle speed before gear shifting is less than the preset speed threshold, judging whether the absolute value of the road slope percentage is less than a preset slope percentage according to the current single-step path environment information; Step a5, when the absolute value of the road slope percentage is less than the preset slope percentage, judging whether the lateral error of the vehicle is less than a corresponding preset error threshold; Step a6, when the lateral error is less than the corresponding preset error threshold, determining that the early gear shifting condition is met.

[0060] Specifically, as shown in Figure 3 The embodiment of the present application provides five kinds of judgment condition verification when performing the early gear shifting condition judgment, and ensures that the early gear shifting is triggered only in the optimal scenario.

[0061] In the step, it is judged according to the current single-step path environment information whether the single-step path length is greater than a preset distance threshold. The single-step path length refers to the straight-line distance (unit: m) from the starting point to the ending point of the current planned single-step parking path, which is generated by the path planning algorithm based on the environment data collected by the surround-view camera and the radar. The preset distance threshold is a safety distance value calibrated by a real vehicle (for example, it is set to 60 cm in some scenarios, which can be adjusted according to the size of the vehicle, and is only used as an example, not limited thereto), and the setting basis is to avoid the jerk problem of torque shifting in a short path. If the single-step path length is too short (for example, less than 60 cm), even if the early gear shifting is performed, there is not enough distance for the motor torque to decrease from the current value to 0, which will inevitably cause the "torque shifting", and the over-zero impact when the motor reverses (the motor output force suddenly changes from positive to negative), and finally causes the whole vehicle to jerk, affecting the driving experience. Therefore, only when the single-step path length is greater than the threshold, the basic condition for early gear shifting is met, otherwise the judgment is terminated and the traditional stable parking shifting mode is switched.

[0062] In the step, it is judged according to the current single-step path environment information whether the distance between the vehicle and the obstacle is greater than a preset distance threshold. The distance between the vehicle and the obstacle refers to the straight-line distance between the vehicle body and the nearest obstacle (such as other vehicles, columns, and road kerbs), which is collected in real time by ultrasonic radar and angle radar. The preset distance threshold is consistent with the foregoing step, and the core purpose is to ensure safety and driving confidence. If the distance to the obstacle is too close, on the one hand, the driver will feel uneasy due to the lack of additional braking redundancy, and on the other hand, the vehicle needs to reduce the torque to avoid collision at close range, and the torque reduction will result in reduced braking effect, which may cause the sliding distance to exceed the safe range and approach the obstacle, so it is necessary to ensure that the obstacle distance meets the standard before entering the next judgment link.

[0063] In the step, it is judged according to the vehicle information whether the actual vehicle speed before gear shifting is less than a preset speed threshold. The actual vehicle speed before gear shifting refers to the real-time driving speed (unit: km / h) before the vehicle performs the gear shifting action, which is collected and converted by the wheel speed sensor. The preset speed threshold is the optimal value of the low-speed parking scene (usually set to 1.5 kph), and the setting logic is to avoid high-speed sliding beyond the standard. If the vehicle speed is too high, the vehicle will continue to slide at a high speed due to inertia after gear shifting, and even if the torque is reduced subsequently, the sliding distance will be too long (may exceed the remaining length of the current path), which not only affects the parking accuracy, but also makes the driver feel out of control, reducing the experience. Therefore, only when the vehicle speed is lower than the threshold, the speed condition for early gear shifting is met.

[0064] Wherein, it is judged according to the current single-step path environment information whether the absolute value of the road slope percentage is less than the preset slope percentage. The road slope percentage refers to the degree of inclination of the road surface at the current vehicle position (calculation formula: slope%= (height difference of road surface / horizontal distance) x 100, positive value for uphill, negative value for downhill), which is converted from the vertical direction acceleration collected by the vehicle acceleration sensor. The preset slope percentage is the critical value for avoiding ramp jerk (usually set to 3%-5%), and the core reason is that additional compensation force is needed under large slope, which is easy to cause jerk. If the slope is too large (such as greater than 5% in absolute value), additional torque is needed to overcome gravity to prevent the vehicle from sliding uphill, additional brake pressure is needed to offset gravity acceleration downhill, and quick switching of "pressure relief and torque increase" or "pressure building and torque reduction" actions is needed during shifting. The rapid action of the actuator will cause sudden changes in the force on the vehicle body, resulting in obvious jerk. Therefore, only when the absolute value of the slope is below the threshold, the subsequent judgment is entered.

[0065] Wherein, it is judged whether the lateral error of the vehicle is less than the corresponding preset error threshold. The "lateral error" includes lateral position error and lateral angle error, the lateral position error refers to the offset distance (unit: cm) of the actual driving track of the vehicle and the planned path in the left and right directions, and the lateral angle error refers to the included angle (unit: °) between the current driving direction of the vehicle and the direction of the planned path, both of which are calculated by comparing the road marking and parking space line data collected by the surround view camera with the planned path. The corresponding preset error threshold is the accurate value for ensuring path tracking (usually the lateral position error threshold is set to 5-8 cm, and the lateral angle error threshold is set to 10°), which aims to avoid path deviation after shifting. If the lateral error is too large, the system needs to handle shifting control and direction correction during shifting, which will disperse control power, resulting in a decrease in path tracking ability, and the vehicle may further deviate from the planned path, ultimately failing to accurately park in the target parking space. Therefore, it is necessary to ensure that the lateral error is below the threshold to meet the last judgment condition.

[0066] Wherein, when all the above conditions are met, it is determined that the early shifting condition is met. At this time, the environment of the current single-step path is safe (the path length and obstacle distance meet the standard), the vehicle state is stable (the speed and slope are suitable), and the path tracking is accurate (the lateral error is qualified), all key factors affecting the safety and smoothness of early shifting meet the requirements, and the decision planning end can enter the subsequent "determine early shifting position" process, and send the "ready to shift flag" to the controller, so that the vehicle motion control part starts to plan the control target of early shifting. If any of the previous steps is not met, the early shifting judgment is terminated, and the traditional stable shifting mode is maintained to ensure the safety and comfort of the parking process.

[0067] The embodiment of the present application screens through "path-obstacle-vehicle speed-gradient-lateral error", comprehensively covers the core risk points of early gear shifting, avoids specific problems such as short path frustration, close-range collision, high-speed overslip, large-gradient jitter and lateral deviation, ensures the practicability of the judgment standard through the threshold of real vehicle calibration, triggers early gear shifting only in the scene of "safety, smoothness and precision", maximizes the advantage of early gear shifting to improve parking efficiency, and guarantees the driving experience and parking safety.

[0068] In some optional embodiments, the step S204 comprises: Step b1, calculating the gear shifting distance from the starting point of the current single-step path based on the actual vehicle speed before gear shifting, the single-step path length and the road gradient, and determining the early gear shifting position according to the gear shifting distance.

[0069] Specifically, after determining that the early gear shifting condition is met, the early gear shifting position is accurately positioned. The gear shifting distance refers to the cumulative distance (unit: m) required for the vehicle to travel to the early gear shifting position from the starting point of the current single-step path. The early gear shifting position is the physical position corresponding to the gear shifting distance on the current single-step path (for example, the distance from the starting point of the current path to the position is 3 m, that is, the early gear shifting position is 3 m away from the starting point), which needs to be determined through the matching relationship between the gear shifting distance and the current single-step path.

[0070] When calculating the gear shifting distance, the embodiment of the present application needs to call three types of data. One is the actual vehicle speed before gear shifting, which is collected by a wheel speed sensor in real time and reflects the driving state of the vehicle before gear shifting; the second is the single-step path length, which is generated by the environmental data collected by the surround view camera and radar through the path planning algorithm, that is, the total length of the current single-step path from the starting point to the ending point; the third is the road gradient, which is calculated from the vertical acceleration collected by the vehicle acceleration sensor.

[0071] The specific calculation logic needs to consider the synergistic effect of the three types of data. After completing the calculation of the gear shifting distance, the early gear shifting position can be determined. Taking the starting point of the current single-step path as the origin, the length equal to the gear shifting distance is taken along the path travel direction, and the position corresponding to the length is the early gear shifting position. For example, if the starting point of the current single-step path is the initial parking point of the vehicle and the gear shifting distance is calculated as 0.93 m, then the position 0.93 m ahead (or behind, depending on the gear direction) of the starting point along the current path is the early gear shifting position.

[0072] The multi-dimensional calculation logic of the vehicle speed determination basis, the path length control redundancy and the slope deviation compensation avoids the limitation of the traditional fixed distance gear shifting (such as gear shifting at 2m from the starting point regardless of the road condition), enables the gear shifting distance to adapt to different vehicle speed, path length and slope scenarios, ensures that the gear shifting position neither causes the torque to be unable to be timely reduced (causing the gear shifting jerk) due to being too close, nor loses the efficiency advantage of the early gear shifting due to being too far, and lays a foundation for subsequent smooth gear shifting and accurate parking.

[0073] In some optional embodiments, the above step b1 comprises: Step c1, calculating the gear shifting theoretical distance through the ratio of the actual vehicle speed before gear shifting and the comfortable braking deceleration; Step c2, calculating the first distance for reducing the gear shifting theoretical distance through the single-step path length and the distance conversion coefficient; Step c3, calculating the second distance for reducing the gear shifting theoretical distance through the road slope and the slope conversion coefficient; Step c4, determining the gear shifting distance through the difference between the gear shifting theoretical distance, the first distance and the second distance.

[0074] Specifically, the process of calculating the gear shifting distance of the embodiments of the present application is to first determine the theoretical reference distance, and then accurately correct it in combination with the path length and the slope, so as to ensure that the gear shifting distance meets the comfortable braking requirement and adapts to the safety constraints of the actual scenario. The specific process is as follows: First, the gear shifting theoretical distance is calculated through the ratio of the actual vehicle speed before gear shifting and the comfortable braking deceleration. The gear shifting theoretical distance (denoted as ) is a basic distance obtained only based on the vehicle speed and the comfortable braking requirement, and is the reference for subsequent correction. The actual vehicle speed before gear shifting (denoted as ) is collected by a wheel speed sensor in real time, reflecting the driving inertia of the vehicle before gear shifting. The comfortable braking deceleration is a fixed value calibrated by a real vehicle (set to in the present scheme), and the setting of the value takes the core target of "no jerk in the braking process and no impact feeling for the driver and passenger", and needs to meet the accuracy requirement that the distance between the vehicle and the path end at the end of the automatic parking single step is controlled within 0-10cm. The specific calculation uses the formula (the units of the parameters in the formula are uniform, and the constant "5" is a safety redundancy distance verified by a real vehicle, avoiding that the theoretical calculation value is too small to cause the braking to be not timely).

[0075] Then, the first distance for reducing the gear shifting theoretical distance is calculated through the single-step path length and the distance conversion coefficient. The first distance (denoted as ) is a correction amount set to solve the problem of "short single-step path length leading to torque shifting", which is used to shorten the shifting theoretical distance to avoid the situation that the shifting position is too far behind (close to the path endpoint) and there is not enough distance to reduce torque. The single-step path length (denoted as ) is generated by the path planning algorithm based on the environmental data collected by the surround view camera and radar, and reflects the total length of the current single-step path. The "distance conversion coefficient" is a fixed proportion calibrated by the real vehicle (1 / 10 in this scheme), and a constraint of "the first distance minimum value is 5 cm" is set (to avoid excessive correction leading to too small shifting distance). The specific calculation logic uses the formula: (The constant "60" in the formula is the path length critical value, unit: cm, when ≤ 60 cm, ), at this time, the maximum value "5" is taken, that is, the first distance is fixed at 5 cm; when > 60 cm, the proportional calculation is taken and the maximum value with 5 cm is taken). The core of this calculation logic is that when the path length is long enough (> 60 cm), the first distance maintains the minimum correction amount to avoid excessive shortening of the shifting distance; when the path length is too short (≤ 60 cm), the minimum correction amount is still used to ensure the basic shifting distance, which avoids the problem of short path → insufficient shifting distance → torque shifting → whole vehicle jerk.

[0076] Then, the second distance used to shorten the shifting theoretical distance is calculated through the road slope and the slope conversion coefficient. The second distance (denoted as ) is a correction amount set to solve the problem of "rear sliding during hill shifting", which is used to shorten the shifting theoretical distance to ensure that there is enough control margin after shifting to deal with the inertia of the slope. The "road slope" (denoted as , unit: %) is calculated from the vertical acceleration collected by the vehicle acceleration sensor (positive for uphill, negative for downhill), which reflects the gravitational influence of the slope on the vehicle. The "slope conversion coefficient" is a fixed proportion calibrated by the real vehicle (100 in this scheme), and a constraint of "the second distance minimum value is 5 cm" is set (to avoid insufficient correction when the slope is small, leading to too long rear sliding distance affecting driving confidence). The specific calculation logic uses the formula: (The absolute value of the slope is taken because uphill and downhill both need to consider the influence of inertia; the constant "100" is the unit conversion coefficient to convert the slope percentage into a length unit matching the shifting distance). The core of this calculation logic is that the larger the slope, the larger the second distance correction amount, which shortens the shifting distance to make the shifting position closer to the path starting point and reserves more distance to deal with the risk of rear sliding on the slope, avoiding the problem of large slope → far rear sliding → insufficient driving confidence.

[0077] Finally, the shifting distance is determined by the difference between the shifting theoretical distance, the first distance and the second distance. The shifting distance (denoted as ) is the actual distance used for positioning the pre-shift position, and the calculation logic thereof adopts the formula:

[0078] That is, the final shift distance adapted to the current scene is obtained by subtracting the first distance (path correction amount) and the second distance (slope correction amount) from the shift theoretical distance.

[0079] The embodiments of the present application meet the basic requirements of comfortable braking through the logic of setting a theoretical distance as a reference and controlling risks by double correction amounts, and also solve the problems of "path too short to bring torque shift" and "lack of confidence in rear sliding on a slope", and finally obtain a precise shift distance through difference calculation. Compared with the traditional "fixed distance shift", the calculation logic of the present scheme is more suitable for the complex scene of automatic parking, and ensures that the shift position reaches a balance among "comfort, safety and precision", thereby laying a foundation for subsequent smooth shifting and precise parking.

[0080] In some optional embodiments, the above step S205 comprises: Step d1, determining a first target control distance based on the smaller one of a first expected moving distance and an obstacle safety distance, the first expected moving distance being a distance from the vehicle to an end point of the current single-step path, and the obstacle safety distance being a distance at which the vehicle does not collide with the obstacle within the control time; Step d2, calculating a first theoretical target control vehicle speed through the first target control distance; Step d3, determining an actual target control vehicle speed before shift based on a product of a first scaling coefficient and the first theoretical target control vehicle speed, the first scaling coefficient being positively correlated with a remaining moving distance of the current single-step path; Step d4, calculating a target acceleration in an acceleration phase before shift through an error between an actual vehicle speed before shift and the actual target control vehicle speed before shift, and calculating a target acceleration in a deceleration phase before shift through the first target control distance; Step d5, calculating a first motor torque through a deviation between an actual acceleration of the vehicle and a first target acceleration, the first target acceleration being the target acceleration in the acceleration phase before shift or the target acceleration in the deceleration phase before shift.

[0081] Specifically, as shown in Figure 4 and Figure 5 , the embodiments of the present application provide a calculation process of the first motor torque before shift, and the overall logic is "first determine a safe control distance → then calculate an adapted vehicle speed → then push a target acceleration → finally calculate a torque", which ensures that the motor torque before shift can not only control the vehicle to travel smoothly to the shift position, but also reduce the torque in advance to pave the way for shift.

[0082] First, the first target control distance is determined based on the smaller of the first expected movement distance and the obstacle safety distance. Wherein, the first expected movement distance... This is the straight-line distance from the vehicle's current position to the end point of the current single-step path. It is directly output by the decision-making and planning unit based on the path planning results. For example, if the total length of the current single-step path is 5m and the vehicle has already traveled 2m, then... Obstacle safety distance It is the minimum safe distance to ensure that the vehicle does not collide with an obstacle within the controlled time, calculated using the following logic. , The real-time distance between the vehicle and obstacles is collected by ultrasonic radar / corner radar; The actual vehicle speed before shifting gears; The safe distance from obstacles is related to the obstacle type. First target control distance. This is the core constraint distance for the vehicle's movement before shifting gears, and it should be the smaller value between the first expected movement distance and the safe distance from the obstacle. .

[0083] The core of this value selection logic is safety first, avoiding vehicles from approaching obstacles due to traveling the distance to the end of the path, thus ensuring parking safety from the root.

[0084] Next, the first theoretical target control speed is calculated based on the first target control distance. (First theoretical target control speed) The initial target vehicle speed is derived based on the first target control distance and must simultaneously satisfy both "safe speed control" and "vehicle speed limit constraints." The calculation formula is as follows: .in, Speed ​​limit constraints (calibrated by path length and environmental complexity) The desired acceleration is used to dynamically adjust the target vehicle speed. The first target control distance is determined. By matching the target speed with the control distance, frequent braking caused by "short distance but high speed" or inefficiency caused by "long distance but low speed" is avoided, laying a speed foundation for subsequent smooth driving.

[0085] Then, the actual target control speed before gear shifting is determined based on the product of the first scaling factor and the first theoretical target control speed. The first scaling factor... This is a dynamic coefficient that adapts to the remaining travel distance of the current single-step path. Its value ranges from 0 to 1, and it is positively correlated with the remaining travel distance of the current single-step path. The longer the remaining distance, the higher the first scaling factor. The closer the value is to 1, the less efficient the vehicle will be due to low speed; the shorter the remaining distance, the higher the first scaling factor. The closer the speed is to 0, the more the vehicle prepares for shifting gears and reducing torque by reducing speed in advance, thus determining the actual target speed before shifting. The formula is .

[0086] The corresponding target acceleration and target torque are calculated based on the actual target control vehicle speed before shifting, so that the vehicle slows down before reaching the shifting position to meet the vehicle speed condition of the early shifting strategy. Compared with the related art, which relies on hydraulic braking before the vehicle shifts early and relies on reverse torque for deceleration after shifting while reducing hydraulic braking, the influence of brake intervention before the vehicle reaches the end of the path is reduced, and the influence of body jerk and vibration caused by brake pressure building before shifting and pressure relief after shifting is reduced. At the same time, through dynamic coefficient adjustment, the actual target control vehicle speed before shifting not only matches the control distance, but also adapts to the remaining path length, avoiding the problem of "too high torque before shifting" caused by traditional fixed speed, and improving the smoothness of the shifting stage.

[0087] Then, the target acceleration in the acceleration stage before shifting is calculated through the error between the actual vehicle speed before shifting and the actual target control vehicle speed before shifting, and the target acceleration in the deceleration stage before shifting is calculated through the first target control distance. This step needs to divide the driving process before shifting into "acceleration stage" and "deceleration stage". The acceleration stage is used to smoothly increase the vehicle speed from the current actual vehicle speed to the actual target control vehicle speed; the deceleration stage is used to smoothly decelerate the vehicle when approaching the shifting position to ensure that the vehicle speed is in the low inertia interval when shifting, and the deceleration stage needs the participation of the braking system. The target acceleration in the acceleration stage is calculated as follows: Wherein, is the vehicle speed deviation, which is calculated by subtracting the actual target control vehicle speed before shifting from the actual vehicle speed before shifting . is the software calculation period (proportion coefficient of PI control), (integral coefficient of PI control) are parameters calibrated by real vehicle, which need to be considered comprehensively considering road slope, target vehicle speed and vehicle speed deviation.

[0088] The target acceleration in the deceleration stage is calculated as follows: Wherein, is the acceleration calculation coefficient (always negative, considering vehicle speed deviation, remaining distance, road slope and obstacle distance to ensure deceleration effect), is the current actual vehicle speed; is the first target control distance.

[0089] Finally, the first motor torque is calculated through the deviation between the actual vehicle acceleration and the first target acceleration.

[0090] The full-process logic of the safe distance constraint, dynamic vehicle speed adjustment, staged acceleration and accurate torque derivation enables the first motor torque to adapt to the driving demand before gear shifting (providing gentle power when accelerating and providing moderate braking power when decelerating), and to reduce the vehicle speed and torque in advance to facilitate the subsequent gear shifting action, thereby avoiding gear shifting jerk caused by excessive torque before gear shifting, and reducing the frequency of intervention of the braking system, and balancing the smoothness, safety and efficiency of automatic parking.

[0091] In some optional embodiments, the step d5 comprises: Step e1, calculating the first traction force through the deviation between the actual vehicle acceleration and the first target acceleration; Step e2, obtaining the friction compensation force, the wind resistance compensation force and the slope compensation force; Step e3, determining the vehicle driving force based on the sum of the first traction force, the friction compensation force, the wind resistance compensation force and the slope compensation force; Step e4, calculating the first motor torque through the vehicle driving force.

[0092] Specifically, the embodiments of the present application first split and calculate various driving forces and compensation forces in the driving process, then sum up the vehicle driving force, and finally derive the wheel end torque that the motor needs to output, so as to ensure that the first motor torque can meet the power demand of the vehicle before gear shifting and accurately offset the environmental disturbances such as friction and slope.

[0093] First, the first traction force is calculated through the deviation between the actual vehicle acceleration and the first target acceleration. The first traction force is a core power component for compensating the vehicle acceleration resistance, and its role is to make the actual vehicle acceleration approach the first target acceleration, and the calculation logic is:

[0094] In the formula: is the acceleration deviation, which is calculated by subtracting the actual acceleration from the target acceleration; and are the proportional coefficient and the integral coefficient for calculating the target torque in the PI control algorithm, which are obtained by comprehensively considering the road slope, the path length and the acceleration deviation.

[0095] Then, the friction compensation force , the wind resistance compensation force and the slope compensation force are obtained. The three types of forces are environmental disturbance compensation components, the friction compensation force is used to compensate the friction between the wheels and the ground, and is calculated by comprehensively considering the vehicle mass, whether the vehicle is stationary, the actual vehicle speed and the road slope; the wind resistance compensation force The wind resistance compensation force is used for compensating the wind resistance when the vehicle is running, and since the automatic parking is low-speed parking, the vehicle speed is generally not more than 5kph, so it can be approximated to 0 and ignored in calculation; the slope compensation force The slope compensation force is used for compensating the gravity component of the vehicle along the slope, and is calculated by comprehensively considering the road slope and the whole vehicle mass, and is positive or negative according to whether the road is uphill or downhill.

[0096] The friction compensation force is automatically calculated by calling a pre-stored calibration model of the whole vehicle controller. The wind resistance compensation force has little effect on the vehicle running, and can be approximated to 0, so it is not necessary to additionally collect or calculate in actual calculation. The slope compensation force needs to overcome gravity when uphill, and the slope compensation force is positive; when downhill, the slope compensation force needs to offset the acceleration trend caused by gravity, and the slope compensation force is negative, and the value is calculated by the whole vehicle controller according to real-time slope data.

[0097] The whole vehicle driving force is determined based on the sum of the first traction force, the friction compensation force, the wind resistance compensation force and the slope compensation force in the embodiment of the application. The whole vehicle driving force is the total power required for the vehicle to stably run before shifting, The first motor torque is finally calculated by the whole vehicle driving force. The wheel end torque is obtained by referring to the wheel end torque calculation formula The wheel end torque is converted into the first motor torque by the conversion coefficient of the transmission system, and is used for controlling the vehicle motor.

[0098] The embodiment of the application solves the drawbacks of the traditional torque calculation which ignores the scene difference by accurately calculating the traction force and comprehensively compensating the environmental interference. The whole vehicle driving force is always matched with the actual driving demand by ensuring the accuracy of acceleration control through the PI algorithm and offsetting the external resistance through the friction and slope compensation force. Before shifting, the motor outputs according to the first motor torque, which can realize the driving control of “low jerk and high smoothness”, lays a stable power foundation for the subsequent pre-shift action, and adapts to different parking scenes such as flat road and slope, thereby improving the universality and reliability of the control method.

[0099] In some optional embodiments, the above step S206 comprises: Step f1, determining a second target control distance based on the smaller one of a second expected moving distance and an obstacle safety distance, the second expected moving distance being the distance from the vehicle to the end point of the next single-step path, and the obstacle safety distance being the distance at which the vehicle does not collide with the obstacle within the control time; Step f2, calculating a second theoretical target control vehicle speed through the second target control distance; ​Step f3, determining the actual target control vehicle speed after gear shifting based on the product of the second scaling coefficient and the second theoretical target control vehicle speed, the second scaling coefficient being positively correlated with the remaining moving distance of the next single-step path, and the second scaling coefficient being 1 if the next single-step path does not need to be shifted in advance; Step f4, calculating the acceleration phase target acceleration after gear shifting through the error between the actual vehicle speed after gear shifting and the actual target control vehicle speed after gear shifting, and calculating the deceleration phase target acceleration after gear shifting through the second target control distance; Step f5, calculating the second motor torque through the deviation between the actual vehicle acceleration and the second target acceleration by using a PI control algorithm, wherein the second target acceleration is the acceleration phase target acceleration after gear shifting or the deceleration phase target acceleration after gear shifting, the actual step-up length of the second motor torque is configured to be greater than a default step length, the proportional coefficient in the PI control algorithm is increased by an amplification coefficient, and the integral coefficient in the PI control algorithm is increased or decreased by a reduction coefficient, the amplification coefficient is positively correlated with the target vehicle speed of the next single-step path, the reduction coefficient is positively correlated with the target vehicle speed of the next single-step path, and the target vehicle speed of the next single-step path is determined based on the next single-step path environment information.

[0100] Specifically, for the calculation of the second motor torque, the calculation process is similar to that of the first motor torque, but the embodiment of the present application optimizes the calculation process for the problem after gear shifting.

[0101] Firstly, the second target control distance is determined based on the smaller value between the second expected moving distance and the obstacle safety distance. The second expected moving distance is the straight-line distance from the current position of the vehicle to the end point of the next single-step path, which is output by the decision planning end according to the next path planning result. The obstacle safety distance is the minimum distance to ensure that the vehicle does not collide with the obstacle within the control time after gear shifting, which is determined in the same way as in the foregoing embodiment. The second target control distance is the core safety constraint for the vehicle to travel after gear shifting, and the smaller value between the second expected moving distance and the obstacle safety distance is taken. As the first optimization strategy of the present embodiment, the second target control distance is determined based on the next single-step path immediately after gear shifting when calculating the torque after gear shifting, so that the target torque calculated in the subsequent steps can fully consider the length of the next single-step path, facilitate the target torque to be calculated to be more suitable for the next single-step path, and significantly avoid the problem of vehicle emergency braking caused by the torque after gear shifting.

[0102] Then, the second theoretical target control vehicle speed is calculated through the second target control distance, and the calculation principle is the same as that of calculating the first theoretical target control vehicle speed in the foregoing embodiment, which will not be described here.

[0103] Then, the actual target control vehicle speed after the gear shift is determined based on the product of the second scaling coefficient and the second theoretical target control vehicle speed. The principle of calculating the actual target control vehicle speed after the gear shift is the same as that of calculating the actual target control vehicle speed before the gear shift, which will not be repeated here.

[0104] It should be noted that in the case where the next single-step path does not need to perform the early gear shift (such as the path being too short or the vehicle having entered the garage), the second scaling coefficient is defined as 1, that is, the actual target control vehicle speed after the gear shift directly travels at the theoretical target vehicle speed without additional speed reduction. The embodiment of the present application adjusts the dynamic coefficient to make the actual target vehicle speed not only match the control distance (again, the scenario of early gear shift) but also adapt to the gear shift demand of the next path, avoiding the problem of "too high reverse driving torque" or "emergency braking when approaching the end point" caused by the traditional fixed vehicle speed.

[0105] Then, the acceleration phase target acceleration after the gear shift is calculated through the error between the actual vehicle speed after the gear shift and the actual target control vehicle speed after the gear shift, and the deceleration phase target acceleration after the gear shift is calculated through the second target control distance. The calculation principle of this step is the same as that of calculating the acceleration phase target acceleration before the gear shift and the deceleration phase target acceleration before the gear shift in the foregoing embodiment, which will not be repeated here.

[0106] Finally, the second motor torque is calculated by using the PI control algorithm through the deviation between the actual vehicle acceleration and the second target acceleration. The second target acceleration participating in the calculation also needs to be dynamically switched according to the driving phase (acceleration phase and deceleration phase).

[0107] Among them, the second optimization strategy of the embodiment, that is, the parameter optimization of the PI control algorithm, adjusts the parameters for the scenario after the gear shift.

[0108] The proportional coefficient is increased by the "amplification coefficient", and the amplification coefficient is positively correlated with the target vehicle speed of the next single-step path. The higher the target vehicle speed, the larger the amplification coefficient, for example, the formula is as follows:

[0109] In the formula, is the adjusted proportional coefficient, is the proportional coefficient before adjustment, is the amplification coefficient, and the value range is between 1 and 2. After the proportional coefficient is increased, the vehicle can speed up faster after the gear shift. According to the proportional torque property, the proportional torque will decrease in advance before the vehicle speed reaches the target, preventing the actual torque from being too large to cause the vehicle speed overshoot, and solving the problem that the PI torque component of the traditional PI control is larger than that in the normal starting condition, thereby causing the vehicle speed overshoot after the gear shift and triggering the subsequent vehicle speed oscillation.

[0110] The integral coefficient is reduced by a "reduction coefficient", which is positively correlated with the target vehicle speed of the next single-step path. The higher the target vehicle speed, the greater the reduction coefficient, to avoid excessive accumulation of the integral term leading to torque overshoot. The formula is as follows:

[0111] In the formula, is a reduction coefficient related to the target vehicle speed of the next path, and the value range is between 0 and 1, is the integral coefficient before adjustment, is the integral coefficient after adjustment.

[0112] Compared with normal starting, the wheel speed direction is inconsistent with the actual gear for a short time after early gear shifting. During this period, the acceleration deviation will be large due to the negative actual vehicle acceleration, which will lead to continuous accumulation of integral torque. Excessive accumulation of integral torque will lead to overshoot of the starting speed and make the torque request of the subsequent entire parking process more uncontrollable. In severe cases, it will cause torque request oscillation. Therefore, the embodiment of the present application reduces the integral torque request during wheel reverse rotation, solves the problem that the PI torque component of the traditional PI control is larger than that in the normal starting condition, and thus causes the speed overshoot after gear shifting starting, which triggers the subsequent speed oscillation.

[0113] The third optimization of the embodiment is the torque rising step. Because the vehicle motion direction is inconsistent with the gear direction after performing early gear shifting, the opposite vehicle speed needs to be reduced to 0 first, and then the motion direction is changed and the speed is increased to the target speed. In order to adapt to the above physical law, the actual rising step of the second motor torque is configured to be greater than the default step in the embodiment of the present application, to ensure that the reverse torque is quickly established and to avoid the vehicle from continuing to slide forward too far due to slow torque rising.

[0114] The motor torque control strategy provided by the embodiment of the present application allows the second motor torque to adapt to the special requirements of "direction switching" after gear shifting (fast reverse and short sliding) and accurately match the driving requirements of the next path (smooth speed reduction when decelerating and gentle speed increase when accelerating). Compared with the disadvantages of the traditional torque calculation after gear shifting, the embodiment of the present application solves the problems of sliding too far, torque overshoot, and direction switching jerk through parameter optimization and step adjustment, and lays a key foundation for smooth driving and accurate parking of the next path.

[0115] In some optional embodiments, the above step f5 includes: Step g1, calculating the second traction force by using a PI control algorithm based on the deviation between the actual vehicle acceleration and the target acceleration in the deceleration stage; Step g2, obtaining the friction compensation force, wind resistance compensation force, and slope compensation force; Step g3, determining the vehicle driving force based on the first torque force minus the second torque force, the first torque force being the sum of the second traction force and the ramp compensation force, and the second torque force being the sum of the friction compensation force and the wind resistance compensation force; Step g4, calculating the second motor torque through the vehicle driving force.

[0116] Specifically, the principles of calculating the second traction force, the ramp compensation force, the friction compensation force, and the wind resistance compensation force are the same as those of the foregoing embodiments, and will not be described here again. The difference between the foregoing embodiment for calculating the first motor torque and the present embodiment is that the signs of the friction compensation force and the wind resistance compensation force are changed from positive to negative, and the compensation force is subtracted when calculating the total traction force, so as to prevent the request torque from being too high during the wheel reverse rotation, thereby causing subsequent speed overshoot.

[0117] According to the above technical means, the torque calculation is refined in the deceleration stage after the gear shifting, and the difference between the traction torque and the compensation torque is calculated, so as to adapt to the special state that the vehicle moving direction is opposite to the gear position after the gear shifting. The corrected torque calculation logic can effectively offset the interference of friction and wind resistance on the reverse deceleration, so as to ensure that the vehicle quickly and smoothly reduces the speed to 0 and switches the driving direction. The sliding distance caused by insufficient torque in the deceleration stage is avoided, or the jerk caused by excessive torque is avoided, the controllability and smoothness of the deceleration process after the gear shifting are improved, and the safety of the close-range parking scene is ensured.

[0118] In some optional embodiments, the longitudinal control method for early gear shifting in parking provided by the present application further comprises: Step h1, increasing the coasting distance threshold for triggering the coasting emergency braking protection strategy after the gear shifting; Step h2, providing an additional request torque if the moving distance of the vehicle after the gear shifting is greater than the preset sliding distance threshold; Step h3, canceling the acceleration rising step constraint of the vehicle after the gear shifting.

[0119] Specifically, for the special scene that the moving direction of the vehicle is opposite to the gear direction, the sliding risk is high, and the starting response is slow after the early gear shifting, the present embodiment designs three supplementary control strategies, the core of which is to "relax the anti-coasting threshold, supplement the braking torque, and cancel the acceleration constraint", so as to optimize the driving experience after the gear shifting while ensuring safety.

[0120] The vehicle slip protection strategy is a basic safety strategy in automatic parking, which means that when the actual moving direction of the vehicle is inconsistent with the gear direction (for example, the gear is in reverse gear but the vehicle still slides forward) and the driving distance reaches a preset threshold, the brake actuator will quickly build pressure to stop the vehicle to prevent collision. However, in the pre-shift scene, the moving direction of the vehicle after shifting is necessarily opposite to the gear direction (for example, the current single-step path is forward gear, and after pre-shifting, the reverse gear is cut in, at this time, the vehicle still moves forward due to inertia), if the slip distance threshold of normal parking (usually set to 5-8 cm) is used, the emergency brake will be triggered frequently, interrupting the normal parking process.

[0121] Therefore, the first supplementary control strategy provided by the embodiment of the present application relaxes the trigger condition by "increasing the slip distance threshold", specifically, dynamically adjusting the threshold according to the initial vehicle speed and road slope after shifting. For example, the normal parking slip distance threshold is 6 cm, if the initial vehicle speed is 2 km / h and the road slope is 1% after shifting, the threshold is increased to 15-20 cm; if the initial vehicle speed is 1 km / h and the road slope is 0, the threshold is increased to 12-15 cm. The core basis of threshold adjustment is to cover the normal sliding distance from the opposite direction to the consistent direction after shifting, for example, the vehicle needs to slide forward for 10 cm after shifting to reduce the speed to 0 and start in reverse, at this time, the threshold is set to 15 cm, which can avoid triggering the emergency brake during normal sliding, and can also start protection in time when the actual slip distance exceeds 15 cm, balancing the continuity and safety of the parking process.

[0122] Secondly, if the moving distance of the vehicle after shifting is greater than the preset sliding distance threshold, an additional requested torque is provided. The preset sliding distance threshold is a safety boundary value calibrated by a real vehicle, which is used to determine whether the vehicle after shifting has the risk of "sliding too far", and its value needs to be determined in combination with the remaining distance of the current single-step path and the obstacle distance. The moving distance of the vehicle after shifting refers to the cumulative distance of the vehicle sliding in the original direction (opposite to the gear direction) from the completion of the shifting action to the current time, which is calculated from the number of wheel rotations collected by the wheel speed sensor and the tire circumference.

[0123] When the moving distance is greater than the preset sliding distance threshold, an additional requested torque needs to be provided, which is a reverse brake torque consistent with the gear direction, and the torque size is dynamically calculated according to the exceeding distance, the more the exceeding distance, the greater the additional requested torque, the core function is to quickly reduce the sliding speed to avoid the vehicle approaching the obstacle or the path endpoint. At the same time, when the wheel rotation direction is consistent with the gear direction (i.e., the vehicle changes from sliding to driving in the direction of the gear), the additional torque request needs to be immediately cleared to prevent the additional torque and the normal driving torque from being superimposed to cause the vehicle speed to overshoot.

[0124] Thirdly, the acceleration rise step constraint of the vehicle is cancelled after the gear shifting. The acceleration rise step constraint is a smooth control strategy in normal parking, which refers to limiting the rise of acceleration (such as the acceleration rise of no more than 0.1 m / s2 per 100 ms) to prevent the acceleration from rising sharply, causing the torque request to surge and the brake pressure to decrease too fast, causing the vehicle body to shake. However, in the pre-gear shifting scenario, the acceleration of the vehicle needs to be quickly switched from the negative value in the braking stage to the positive value in the starting stage. If the acceleration rise step constraint is kept, the acceleration switching will be delayed, and the vehicle cannot start in reverse in time due to the insufficient acceleration, resulting in the problem of slow starting after the gear shifting.

[0125] Therefore, the embodiment of the present application cancels the limitation on the acceleration rise amplitude immediately after the gear shifting action is completed, allows the acceleration to be quickly adjusted according to the target demand, ensures that the vehicle can obtain the reverse starting acceleration in time after the gear shifting, and avoids the problem of too long sliding distance caused by the starting delay. At the same time, the adjustment is only for the transition stage of the acceleration from negative to positive after the gear shifting. When the acceleration is stable at the target starting acceleration, the system will re-enable the acceleration rise step constraint to prevent the acceleration from changing sharply and causing jerk in the subsequent driving, and to balance the starting response speed and the smoothness in normal driving.

[0126] The technical solution provided by the embodiment of the present application not only fills the gap of the basic control logic in the special scenario, but also ensures safety and smoothness through dynamic adjustment and boundary control, further improving the practicality and reliability of the pre-gear shifting longitudinal control method of the present application.

[0127] In some optional embodiments, before the step S206, the method further includes: Step I1, when the gear shifting is performed, the motor torque is adjusted to 0; Step I2, if the gear shifting is performed from the flat road or uphill scenario to the downhill scenario, the brake force is linearly increased through the brake actuator until the downhill acceleration is stable, wherein the slope of the linearly increased brake force is positively correlated with the slope change amount; Step I3, if the gear shifting is performed from the downhill scenario to the flat road or uphill scenario, the brake force is linearly decreased through the brake actuator until the brake pressure is reduced to 0.

[0128] Specifically, the embodiment of the present application further provides a core cooperative control link in the pre-gear shifting execution moment, and the core logic is to first disconnect the torque to prevent jerk, and then modulate the brake according to the scenario. Through the combination strategy of torque zero and linear brake adjustment, the problem of vehicle body shaking caused by torque reversal and brake pressure sudden change during gear shifting is solved.

[0129] When the shift is performed, the requested torque of the motor is adjusted to 0. The core purpose is to avoid the jerk caused by the "shift with torque". If the motor still outputs non-zero torque (such as forward driving torque or reverse braking torque) when the shift is performed, the power actuator switches the gear, and the motor needs to be quickly stopped and started in reverse from the "loaded state". This way of "jerky shift" is easy to produce zero-crossing impact (the output force of the motor is momentarily reversed), which causes the vehicle to have obvious jerk, affecting the driving experience.

[0130] Therefore, when the motion control module sends the "execute early shift flag" (i.e., triggers the shift action) to the control target output end, the control end immediately issues a torque zero command to the power control system, requiring the motor requested torque to decrease from the current value to 0 N at a preset rate m. The rate needs to be calibrated on the actual vehicle to ensure that the torque decreases smoothly without impact.

[0131] If the shift is performed from a flat road or uphill scene to a downhill scene, the embodiment of the present application linearly increases the braking force through the brake actuator until the downhill acceleration is stable, wherein the slope of the linearly increasing braking force is positively correlated with the slope change. After the shift, the vehicle has a tendency to "naturally accelerate and slide" due to gravity, and the brake pressure needs to be established in advance to offset the gravity to avoid the vehicle speed out of control after the shift. The "linearly increasing braking force" is to prevent the jerk caused by the sudden increase of the brake pressure. The linear pre-bleeding operation of the brake system gradually increases the brake master cylinder pressure by requesting the braking force at a fixed slope until the downhill acceleration is closed looped (i.e., the actual acceleration of the vehicle follows the target acceleration), and the slope of the requested braking force is positively correlated with the slope change.

[0132] If the shift is performed from a downhill scene to a flat road or uphill scene, the braking force is linearly reduced through the brake actuator until the brake pressure is reduced to 0 bar. The core feature of the shift from a downhill scene to a flat road or uphill scene is that a high brake pressure has been established to offset the gravity before the shift, and the gravity effect is weakened or eliminated after the shift, and the brake pressure needs to be reduced to avoid the conflict between braking and power. The "linearly decreasing braking force" is to prevent the vehicle body from being jerked caused by the sudden decrease of the brake pressure. The pre-bleeding operation of the brake system is to decrease the braking force request at a certain slope to gradually reduce the brake pressure to 0 bar.

[0133] The embodiment of the present application avoids the jerk of the "shift with torque" from the root by "torque zero", and eliminates the impact of the sudden change of the brake pressure by "scene-based linear brake adjustment", and the two achieve the "sensationless transition" of the shift action. Compared with the traditional shift logic of "shift first and then adjust the brake", the torque and brake control are integrated into the shift execution moment, which not only adapts to the brake demand of different scenes such as flat roads and slopes, but also ensures the smoothness and stability of the vehicle during the shift process, further improving the scene adaptation ability and driving experience of the early shift longitudinal control method of the present application.

[0134] A longitudinal control device for early gear shifting in parking is also provided in the embodiment, which is used to implement the above-mentioned embodiments and preferred embodiments, and will not be described again. As used below, the term "module" can be a combination of software and / or hardware that implements a predetermined function. Although the device described in the following embodiments is preferably implemented in software, implementation of hardware, or a combination of software and hardware, is also possible and contemplated.

[0135] The embodiment provides a longitudinal control device for early gear shifting in parking, which comprises: Figure 6 An information acquisition module 601, configured to acquire vehicle information, current single-step path environment information and next single-step path environment information; A gear position determination module 602, configured to determine an early gear shifting position of the vehicle on the current single-step path according to the vehicle information and the current single-step path environment information; A pre-gear shifting control module 603, configured to output a first motor torque before the early gear shifting position according to the vehicle information and the current single-step path environment information, the first motor torque being used to control the vehicle to travel on the current single-step path before gear shifting; A post-gear shifting control module 604, configured to output a second motor torque after the early gear shifting position according to the vehicle information and the next single-step path environment information, the second motor torque being used to control the vehicle to travel on the current single-step path after gear shifting.

[0136] The device provided by the embodiment of the application can execute the method provided by any of the embodiments of the application, and has the corresponding function modules and advantages of executing the method. The further function description of each module and unit is the same as that of the corresponding embodiment, and will not be described here.

[0137] Figure 7 A structural schematic diagram of an electronic device provided by the embodiment of the application is provided.

[0138] The following will be specifically described with reference to Figure 7 which shows a structural schematic diagram of an electronic device suitable for implementing the electronic device in the embodiment of the application. The electronic device can include a processor (such as a central processor, a graphic processor, etc.) 701, which can perform various appropriate actions and processes according to programs stored in a read-only memory (ROM) 702 or programs loaded from a storage 708 into a random access memory (RAM) 703. In the RAM 703, various programs and data required for the operation of the electronic device are also stored. The processor 701, the ROM 702, and the RAM 703 are connected to each other through a bus 704. An input / output (I / O) interface 705 is also connected to the bus 704.

[0139] ​Generally, the following devices can be connected to the I / O interface 705: input devices 706, including, for example, a touch screen, a touch pad, a keyboard, a mouse, a camera, a microphone, an accelerometer, a gyroscope, and the like; output devices 707, including, for example, a liquid crystal display (LCD), a speaker, a vibrator, and the like; storage devices 708, including, for example, a magnetic tape, a hard disk, and the like; and communication devices 709. The communication devices 709 can allow the electronic device to communicate wirelessly or wiredly with other devices to exchange data. Although Figure 7 An electronic device having various devices is illustrated, but it is understood that all of the illustrated devices are not required and more or fewer devices can alternatively be implemented.

[0140] In particular, the processes described above with reference to the flowcharts can be implemented as a computer software program according to embodiments of the present application. For example, embodiments of the present application include a computer program product comprising a computer program carried on a non-transitory computer-readable medium, the computer program containing program code for executing the methods illustrated by the flowcharts. In such embodiments, the computer program can be downloaded and installed from a network through the communication devices 709, or installed from the storage devices 708, or installed from the ROM 702. When the computer program is executed by the processor 701, the above-described functions defined in the embodiments of the present application method are performed.

[0141] Figure 7 The electronic device illustrated is merely one example and should not be taken as limiting the scope of the functionality and use of embodiments of the present application.

[0142] Embodiments of the present application also provide a computer-readable storage medium, the above-mentioned method according to embodiments of the present application can be implemented in hardware, firmware, or as computer code recorded on a storage medium, or as computer code originally stored in a remote storage medium or non-transitory machine-readable storage medium and downloaded through a network and to be stored in a local storage medium, so that the method described herein can be processed by such software on a storage medium using a general-purpose computer, a special-purpose processor, or programmable or special-purpose hardware. Among them, the storage medium can be a magnetic disk, an optical disk, a read-only memory, a random access memory, a flash memory, a hard disk or a solid state disk, etc.; further, the storage medium can also include a combination of the above types of storage. It can be understood that the computer, processor, microprocessor controller or programmable hardware includes a storage component that can store or receive software or computer code, when the software or computer code is accessed and executed by the computer, processor or hardware, the method illustrated by the above embodiments is implemented.

[0143] Part of the present application can be applied as a computer program product, for example, computer program instructions, when executed by a computer, through the operation of the computer, can invoke or provide the method and / or technical solutions according to the present application. Those skilled in the art should understand that the form of computer program instructions in computer readable medium includes but is not limited to source files, executable files, installation package files and the like, and accordingly, the way of computer program instructions executed by computer includes but is not limited to: the computer directly executes the instructions, or the computer compiles the instructions and then executes the corresponding compiled program, or the computer reads and executes the instructions, or the computer reads and installs the instructions and then executes the corresponding installed program. Here, the computer readable medium can be any available computer readable storage medium or communication medium accessible to the computer.

[0144] Although the embodiments of the present application are described in conjunction with the drawings, various modifications and changes can be made by those skilled in the art without departing from the spirit and scope of the present application, and such modifications and changes fall within the scope defined by the appended claims.

Claims

1. A longitudinal control method for parking pre-shift, characterized in that, The method comprises: acquiring vehicle information, current single-step path environment information and next single-step path environment information; determining an advance shift position of the vehicle driving on the current single-step path according to the vehicle information and the current single-step path environment information; outputting a first motor torque before the advance shift position according to the vehicle information and the current single-step path environment information, the first motor torque being used to control the vehicle driving on the current single-step path before shifting; outputting a second motor torque after the advance shift position according to the vehicle information and the next single-step path environment information, the second motor torque being used to control the vehicle driving on the current single-step path after shifting.

2. The method of claim 1, wherein, Before the step of determining the advance shift position of the vehicle driving on the current single-step path according to the vehicle information and the current single-step path environment information, the method further comprises: judging whether an advance shift condition is met according to the vehicle information and the current single-step path environment information; when the advance shift condition is met, performing the step of determining the advance shift position of the vehicle driving on the current single-step path according to the vehicle information and the current single-step path environment information.

3. The method of claim 2, wherein, The step of judging whether the advance shift condition is met according to the vehicle information and the current single-step path environment information comprises: judging whether a single-step path length is greater than a preset distance threshold according to the current single-step path environment information; when the single-step path length is greater than the preset distance threshold, judging whether a distance between the vehicle and an obstacle is greater than the preset distance threshold according to the current single-step path environment information; when the distance between the vehicle and the obstacle is greater than the preset distance threshold, judging whether an actual vehicle speed before shifting is less than a preset speed threshold according to the vehicle information; when the actual vehicle speed before shifting is less than the preset speed threshold, judging whether an absolute value of a road slope percentage is less than a preset slope percentage according to the current single-step path environment information; when the absolute value of the road slope percentage is less than the preset slope percentage, judging whether a lateral error of the vehicle is less than a corresponding preset error threshold; when the lateral error is less than the corresponding preset error threshold, determining that the advance shift condition is met.

4. The method of claim 1, wherein, The step of determining the advance shift position of the vehicle driving on the current single-step path according to the vehicle information and the current single-step path environment information comprises: calculating a shift distance from a starting point of the current single-step path based on an actual vehicle speed before shifting, a single-step path length and a road slope, and determining the advance shift position according to the shift distance.

5. The method of claim 4, wherein, The step of calculating the shift distance from the starting point of the current single-step path based on the actual vehicle speed before shifting, the single-step path length, the road slope and the shift distance comprises: calculating a shift theoretical distance through a ratio of the actual vehicle speed before shifting and a comfortable braking deceleration; calculating a first distance for reducing the shift theoretical distance through the single-step path length and a distance conversion coefficient; calculating a second distance for reducing the shift theoretical distance through the road slope and a slope conversion coefficient; The shift distance is determined by a difference between the shift theory distance, the first distance and the second distance.

6. The method of claim 1, wherein, The first motor torque before the shift position is output according to the vehicle information and the current single-step path environment information, and comprises: A first target control distance is determined based on a smaller value between a first expected moving distance and an obstacle safety distance, the first expected moving distance being a distance from the vehicle to a terminal point of the current single-step path, and the obstacle safety distance being a distance in which the vehicle does not collide with an obstacle within a control time; A first theory target control vehicle speed is calculated by the first target control distance; An actual target control vehicle speed before the shift is determined based on a product of a first scaling coefficient and the first theory target control vehicle speed, the first scaling coefficient being positively correlated with a remaining moving distance of the current single-step path; An acceleration stage target acceleration before the shift is calculated by an error between an actual vehicle speed before the shift and the actual target control vehicle speed before the shift, and a deceleration stage target acceleration before the shift is calculated by the first target control distance; The first motor torque is calculated by a deviation between an actual vehicle acceleration and a first target acceleration, the first target acceleration being the acceleration stage target acceleration before the shift or the deceleration stage target acceleration before the shift.

7. The method of claim 6, wherein, The first motor torque is calculated by the deviation between the actual vehicle acceleration and the first target acceleration, and comprises: A first traction force is calculated by the deviation between the actual vehicle acceleration and the first target acceleration; A friction compensation force, an air resistance compensation force and a slope compensation force are obtained; A total vehicle driving force is determined based on a sum of the first traction force, the friction compensation force, the air resistance compensation force and the slope compensation force; The first motor torque is calculated by the total vehicle driving force.

8. The method of claim 1, wherein, The second motor torque after the shift position is output according to the vehicle information and the next single-step path environment information, and comprises: A second target control distance is determined based on a smaller value between a second expected moving distance and an obstacle safety distance, the second expected moving distance being a distance from the vehicle to a terminal point of the next single-step path, and the obstacle safety distance being a distance in which the vehicle does not collide with an obstacle within a control time; A second theory target control vehicle speed is calculated by the second target control distance; An actual target control vehicle speed after the shift is determined based on a product of a second scaling coefficient and the second theory target control vehicle speed, the second scaling coefficient being positively correlated with a remaining moving distance of the next single-step path, and the second scaling coefficient being 1 if the next single-step path does not need to be shifted in advance; An acceleration stage target acceleration after the shift is calculated by an error between an actual vehicle speed after the shift and the actual target control vehicle speed after the shift, and a deceleration stage target acceleration after the shift is calculated by the second target control distance; The second motor torque is calculated by a PI control algorithm based on a deviation between an actual acceleration of the vehicle and a second target acceleration, the second target acceleration being an acceleration stage target acceleration after the gear shifting or a deceleration stage target acceleration after the gear shifting, an actual increase step of the second motor torque being configured to be greater than a default step, a proportional coefficient in the PI control algorithm being increased by an amplification coefficient, and an integral coefficient in the PI control algorithm being decreased by a reduction coefficient, the amplification coefficient being positively correlated with a target vehicle speed of a next single-step path, the reduction coefficient being positively correlated with the target vehicle speed of the next single-step path, the target vehicle speed of the next single-step path being determined based on next single-step path environment information.

9. The method of claim 8, wherein, The second motor torque is calculated by a PI control algorithm based on a deviation between an actual acceleration of the vehicle and a second target acceleration, the second target acceleration being an acceleration stage target acceleration after the gear shifting or a deceleration stage target acceleration after the gear shifting, an actual increase step of the second motor torque being configured to be greater than a default step, a proportional coefficient in the PI control algorithm being increased by an amplification coefficient, and an integral coefficient in the PI control algorithm being decreased by a reduction coefficient, the amplification coefficient being positively correlated with a target vehicle speed of a next single-step path, the reduction coefficient being positively correlated with the target vehicle speed of the next single-step path, the target vehicle speed of the next single-step path being determined based on next single-step path environment information. The second motor torque is calculated by a PI control algorithm based on a deviation between an actual acceleration of the vehicle and a second target acceleration, the second target acceleration being an acceleration stage target acceleration after the gear shifting or a deceleration stage target acceleration after the gear shifting, an actual increase step of the second motor torque being configured to be greater than a default step, a proportional coefficient in the PI control algorithm being increased by an amplification coefficient, and an integral coefficient in the PI control algorithm being decreased by a reduction coefficient, the amplification coefficient being positively correlated with a target vehicle speed of a next single-step path, the reduction coefficient being positively correlated with the target vehicle speed of the next single-step path, the target vehicle speed of the next single-step path being determined based on next single-step path environment information. The second motor torque is calculated by a PI control algorithm based on a deviation between an actual acceleration of the vehicle and a second target acceleration, the second target acceleration being an acceleration stage target acceleration after the gear shifting or a deceleration stage target acceleration after the gear shifting, an actual increase step of the second motor torque being configured to be greater than a default step, a proportional coefficient in the PI control algorithm being increased by an amplification coefficient, and an integral coefficient in the PI control algorithm being decreased by a reduction coefficient, the amplification coefficient being positively correlated with a target vehicle speed of a next single-step path, the reduction coefficient being positively correlated with the target vehicle speed of the next single-step path, the target vehicle speed of the next single-step path being determined based on next single-step path environment information. The method further comprises: increasing a coasting distance threshold for triggering a coasting emergency braking protection strategy after the gear shifting; 10. The method of claim 8, wherein, providing an additional requested torque if a moving distance of the vehicle after the gear shifting is greater than a preset coasting distance threshold; canceling an acceleration increase step constraint of the vehicle after the gear shifting. Before outputting the second motor torque after the gear shifting position based on the vehicle information and the next single-step path environment information, the method further comprises: adjusting the motor torque to 0 when the gear shifting is performed; 11. The method of claim 1, wherein, if a flat road or uphill scenario is switched to a downhill scenario when the gear shifting is performed, increasing a braking force by a brake actuator linearly until a stable downhill acceleration is entered, wherein a slope of the linearly increasing braking force is positively correlated with a slope change amount; if a downhill scenario is switched to a flat road or uphill scenario when the gear shifting is performed, decreasing the braking force by the brake actuator linearly until the braking pressure is reduced to 0. The device comprises: an information acquisition module configured to acquire vehicle information, current single-step path environment information, and next single-step path environment information; 12. A longitudinal control device for parking upshifts, characterized in that a gear shifting position determination module configured to determine a gear shifting position in advance for the vehicle to travel on a current single-step path based on the vehicle information and the current single-step path environment information; a pre-gear shifting control module configured to output a first motor torque before the gear shifting position based on the vehicle information and the current single-step path environment information, the first motor torque being used to control the vehicle to travel on the current single-step path before the gear shifting; a post-gear shifting control module configured to output a second motor torque after the gear shifting position based on the vehicle information and the next single-step path environment information, the second motor torque being used to control the vehicle to travel on the current single-step path after the gear shifting. The device comprises: ​ 13. A vehicle characterized by comprising: ​ A memory and a processor, which are connected in communication with each other, the memory storing computer instructions, and the processor executing the computer instructions to perform the method of any one of claims 1 to 11.

14. A computer-readable storage medium, characterized in that, The computer readable storage medium stores computer instructions for causing a computer to perform the method of any one of claims 1 to 11.

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