Automatic parking brake control method and control system, vehicle

Abstract

The present invention relates to an automatic parking brake control method and an automatic parking brake control system. The automatic parking brake control method includes: a path planning step, dividing a designated parking segment into an acceleration segment and a deceleration segment according to a specified ratio; a first control sub-step, setting an acceleration in the acceleration segment so that the vehicle travels at that acceleration; and a second control sub-step, calculating a deceleration in the deceleration segment based on the vehicle's current speed and the remaining distance to the end of the parking segment, and controlling the vehicle speed in an open-loop manner based on the deceleration. According to the present invention, parking accuracy and efficiency can be improved.

Description

Technical Field

[0001] The present invention relates to vehicle control technology, and in particular to an automatic parking brake control method, an automatic parking brake control system and a vehicle. Background Art

[0002] Generally speaking, automated parking involves path planning followed by trajectory tracking. Current automated parking systems typically automatically control speed, eliminating the need for driver control of the accelerator and brakes. Precise braking control is crucial for accurate parking. Precise braking control at each point along a planned line significantly impacts the accuracy of the final parking attempt.

[0003] Speed ​​control is generally used in the existing technology, and there are two main methods: Method 1, closed-loop control is performed at a low speed within the line segment, and then the vehicle is directly braked to a stop at the line segment node; Method 2, a gradual reference speed is planned in advance according to the distance within the line segment, and the vehicle is braked to a stop at the line segment point with a reference speed of 0 as much as possible.

[0004] Existing technologies are based on a speed closed loop to achieve the purpose of accurately controlling the real-time vehicle speed. However, closed-loop speed control has its own disadvantages:

[0005] If the closed-loop control speed is too high, it is easy to produce deviations; on the contrary, if the control speed is too low, the parking time will be longer;

[0006] In actual vehicles, braking force cannot usually be directly controlled, but rather indirectly through a deceleration control device. If speed closed-loop control is used, the closed-loop system becomes a double closed-loop when the brake device is controlled. When performing gradual speed control, the system's braking is prone to oscillation, greatly affecting parking stability and customer comfort.

[0007] To achieve good control effects, the speed curve design must be combined with vehicle dynamics, etc. The design is relatively complex and may not actually achieve the expected results. Summary of the Invention

[0008] In view of the above problems, the present invention aims to provide an automatic parking brake control method, an automatic parking brake control system and a vehicle that can improve parking efficiency and parking accuracy.

[0009] An automatic parking brake control method according to one aspect of the present invention is characterized by comprising:

[0010] The path planning step divides the pre-set parking segment into acceleration segments and deceleration segments according to a specified ratio;

[0011] A first control sub-step, in the acceleration section, setting the acceleration so that the vehicle speed causes the vehicle to travel at the acceleration; and

[0012] The second control sub-step is to calculate the deceleration in the deceleration section according to the current speed of the vehicle and the remaining distance to the end point of the parking segment, and control the vehicle speed in an open-loop manner according to the deceleration.

[0013] Optionally, the second control sub-step further includes:

[0014] If the vehicle fails to stop when it has crossed the end of the parking line, control is performed to bring the vehicle to an immediate stop.

[0015] Optionally, the second control sub-step further includes:

[0016] If the vehicle has stopped in advance before reaching the end of the parking segment, the vehicle will start again from the early braking point to the end of the parking segment and will be decelerated in a closed-loop manner after accelerating to a certain distance so that the vehicle creeps to the end of the parking segment.

[0017] Optionally, if the vehicle fails to stop when it creeps to the end of the parking segment, control is performed to make the vehicle stop immediately.

[0018] Optionally, PID control is adopted in the closed-loop mode.

[0019] An automatic parking brake control system according to one aspect of the present invention is characterized by comprising:

[0020] Path planning module, plans and forms parking segment parameters;

[0021] a pre-anchor segment point set generation module, which generates a parking segment based on the parking segment parameters and divides the parking segment into an acceleration segment and a deceleration segment;

[0022] a position determination module for determining the current position of the vehicle in the parking segment based on the wheel speed sensing signal from the wheel speed sensor and the parking segment generated by the pre-anchor segment point set generation module; and

[0023] The first control module is configured to control a deceleration control device of the vehicle as follows: if the vehicle is in the acceleration section, setting the acceleration in the acceleration section so that the vehicle travels at the acceleration; if the vehicle is in the deceleration section, calculating the deceleration based on the current vehicle speed and the remaining distance to the end point of the parking segment, and controlling the vehicle speed in an open-loop manner based on the deceleration.

[0024] Optionally, the first control module further performs the following control: if the vehicle fails to stop when it has crossed the end point of the parking segment, the vehicle is stopped immediately.

[0025] Optionally, the first control module further performs the following control: if the vehicle has braked in advance before reaching the end point of the parking segment, the vehicle is started again from the early braking point to the end point of the parking segment and the vehicle speed is controlled in a closed-loop manner to decelerate after accelerating to a certain distance so that the vehicle creeps to the end point of the parking segment.

[0026] Optionally, the first control module further performs the following control: if the vehicle fails to stop when it creeps to the end of the parking segment, the vehicle is stopped immediately.

[0027] Optionally, PID control is adopted in the closed-loop mode.

[0028] Optionally, the method further comprises: a second control module for controlling the steering system of the vehicle in a closed-loop manner so that the vehicle remains on the parking segment.

[0029] The computer-readable medium of the present invention stores a computer program thereon, and is characterized in that when the computer program is executed by a processor, the above-mentioned automatic parking brake control method is implemented.

[0030] The computer device of the present invention includes a storage module, a processor, and a computer program stored in the storage module and executable on the processor. The computer device is characterized in that the processor implements the above-mentioned automatic parking brake control method when executing the computer program.

[0031] The vehicle of the present invention is characterized by including the above-mentioned automatic parking brake control system. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram showing the parking line segments and speeds under ideal conditions.

[0033] Figure 2 It is a schematic diagram showing the parking line segment and speed when the end point of the parking line segment is crossed. Figure 3 It is a schematic diagram showing the parking segment and speed when the end point of the parking segment has not been reached.

[0034] Figure 4 Schematic diagram showing a parking segment in which speed control is performed in the present invention when the vehicle has not reached the end of the parking segment.

[0035] Figure 5 It is a schematic diagram showing the closed-loop control method of the present invention.

[0036] Figure 6 It is a schematic diagram showing the open-loop control method of the present invention.

[0037] Figure 7 Schematic diagram showing the control method of the present invention under no-brake conditions.

[0038] Figure 8 It is a block diagram showing the structure of the automatic parking brake control system of the present invention.

[0039] Figure 9 FIG2 is a schematic diagram showing the hardware structure of an automatic parking brake control system applied to a vehicle according to an embodiment of the present invention.

[0040] Figure 10 The figure is a flow chart showing the automatic parking brake control system according to one embodiment of the present invention when it is applied to a vehicle. DETAILED DESCRIPTION

[0041] The following describes some of the various embodiments of the present invention, which are intended to provide a basic understanding of the present invention, but are not intended to identify the key or decisive elements of the present invention or to limit the scope of protection.

[0042] For brevity and illustrative purposes, the principles of the present invention are described herein primarily with reference to exemplary embodiments thereof. However, those skilled in the art will readily recognize that the same principles are equally applicable to and may be implemented in all types of automatic parking brake control methods, automatic parking brake control systems, and vehicles, and that any such variations do not depart from the true spirit and scope of this patent application.

[0043] The concept behind the automatic parking brake control method of this invention is to use the vehicle's own braking system (e.g., the EBCM) for open-loop deceleration control during the main parking stroke. If open-loop control is insufficient, the braking system is used for short-term closed-loop control. Specifically, a parking segment is pre-planned and formed, and the segment is divided into acceleration and deceleration segments from the starting point. The following control procedures are then implemented:

[0044] (1) Acceleration in the parking segment, vehicle acceleration, no brake control;

[0045] (2) When the vehicle enters the deceleration section after traveling a certain distance, the required deceleration is calculated by combining the remaining line distance and the current vehicle speed, and the deceleration value is given to the deceleration control device to realize open-loop deceleration braking control of the actual vehicle;

[0046] (3) If the open-loop control produces deviations, appropriate auxiliary control must be performed based on the specific situation (closed-loop control may need to be added). For specific details, please refer to the following description.

[0047] A reasonable ratio is allocated between the acceleration and deceleration segments (also known as "braking segments"). During the acceleration segment, a method (such as idling or lightly accelerating) can be used to increase the vehicle's speed to a certain level. When the vehicle passes the acceleration segment and reaches the deceleration segment, the deceleration required for the remaining segments can be directly calculated to bring the vehicle to a stop at the endpoint of the segment. This invention addresses the braking problem during the deceleration segment.

[0048] The ideal situation for parking brake is that at the end of the parking line segment, the given deceleration is just enough to stop the vehicle. Figure 1 is a diagram showing the ideal parking line and speed. Figure 1 As shown, let the length of the parking segment be L, the acceleration segment be a, and the corresponding deceleration segment be 1-a. The speed of the vehicle when it reaches the end of the acceleration segment is v.

[0049] Then, the calculation formula for the deceleration acc of the remaining deceleration section is:

[0050] acc=-v 2 / (L*(1-a)) / 2

[0051] However, in general, deceleration calculations are not always accurate. Due to factors such as sensor information delays and surface smoothness, the vehicle may overshoot or undershoot the finish line. The following analyzes these two situations.

[0052] Figure 2 It is a schematic diagram showing the parking line segment and speed when the end point of the parking line segment is crossed. Figure 2 As shown in the figure, when crossing the end point, the deceleration is given a larger value and the vehicle can be directly stopped. Therefore, under normal circumstances, when approaching the end point of the line segment, the speed is generally smaller. At this time, directly giving a larger deceleration value will not produce a large error, that is, it is within an acceptable range.

[0053] Figure 3 This is a schematic diagram showing the parking line segment and speed when the end of the parking line segment has not been reached. This situation often occurs when deceleration open loop control is performed. Figure 3 As shown, the vehicle will usually stop early at the line point.

[0054] One of the improvements of the present invention is how to restart the vehicle and continue driving to a stop at a line segment point. The present invention adopts a combination of "open-loop control + closed-loop control." That is, if the open-loop deceleration method cannot make the vehicle reach the end point, the remaining line segment is continued using a small closed-loop method.

[0055] Figure 4 Schematic diagram of the parking segment in which the speed is controlled in the present invention when the vehicle has not reached the end of the parking segment. Figure 4 As shown, the combination of "open-loop control + closed-loop control" ensures that even if errors occur in the open-loop deceleration calculation, the remaining errors can be compensated by using a small, low-speed closed-loop method. Because of the low-speed closed-loop method, the remaining errors generally ensure that the vehicle passes the line point at a lower speed. If the vehicle passes the parking line end point without stopping, the braking value is directly applied to the deceleration control device, and the vehicle is immediately stopped. After stopping, the errors are also within a small range.

[0056] Specifically, an automatic parking brake control method according to an embodiment of the present invention includes the following steps:

[0057] The path planning step is to divide the set parking segment into acceleration segment and deceleration segment according to the specified ratio;

[0058] A first control sub-step is to set the acceleration in the acceleration section so that the vehicle travels at the acceleration; and

[0059] The second control sub-step is to calculate the deceleration in the deceleration section according to the current speed of the vehicle and the remaining distance to the end point of the parking segment, and control the vehicle speed in an open-loop manner according to the deceleration.

[0060] Wherein, the second control sub-step further includes:

[0061] If the vehicle fails to stop after crossing the end of the stop line, the vehicle will be stopped immediately;

[0062] If the vehicle has stopped in advance before reaching the end of the parking segment, the vehicle will be started again from the early stopping point to the end of the parking segment and the vehicle speed will be controlled in a low-speed closed-loop manner after accelerating to a certain distance so that the vehicle creeps to the end of the parking segment. Moreover, if the vehicle fails to stop when it creeps to the end of the parking segment, the vehicle will be stopped immediately.

[0063] Preferably, PID control is adopted in the low-speed closed-loop mode.

[0064] As mentioned above, in the acceleration section of the parking segment, a no-brake acceleration section is adopted, and the vehicle's free idle acceleration can be used, and the speed is not very fast, generally less than the idle value, so as to increase the vehicle to a higher speed value within a safe and controllable range as much as possible, thereby shortening the parking time.

[0065] During the deceleration segment, the deceleration value for the remaining segment is calculated in real time based on the current speed and the remaining distance. This deceleration value is then assigned to the deceleration control device, implementing open-loop deceleration control. The goal is to bring the vehicle to a complete stop at the segment point. Typically, due to sensor errors and road conditions, the vehicle often fails to stop at the segment point or stops prematurely. In this case, the above-described scheme of the present invention can also achieve stable control, ensuring that the vehicle stops a short distance behind the segment point. Specifically, if the vehicle fails to stop when crossing the segment point, a higher deceleration value is assigned immediately upon crossing the segment point, bringing the vehicle to an immediate stop. Since the vehicle's speed is already low upon crossing the segment point, the immediate braking method minimizes the error generated after crossing the segment point and stopping. If the vehicle stops prematurely, the remaining segments are controlled using a closed-loop deceleration method, causing the vehicle to creep to the segment point at a lower speed. Upon crossing the segment point, a deceleration value is assigned immediately, bringing the vehicle to an immediate stop. Because the closed-loop control is set at a low speed, the error caused by braking after crossing the endpoint is also small. Furthermore, the closed-loop control method ensures that after the initial braking, the vehicle continues to crawl steadily at a low speed to the segment point. As a result, the maximum number of false stops in the parking segment is only one, and the entire parking process remains relatively continuous and smooth.

[0066] The following briefly describes the closed-loop control and open-loop control in the present invention.

[0067] Figure 5 It is a schematic diagram showing the closed-loop control method of the present invention.

[0068] In the present invention, the deceleration control device (EBCM) is used to control the brake. When the loop is closed, the braking type is a deceleration direct setting mode, and the speed PID is used for control. The principle diagram is as follows: Figure 5 shown.

[0069] Figure 6 It is a schematic diagram showing the open-loop control method of the present invention.

[0070] like Figure 6 As shown in the figure, when the loop is open, the PID link is removed and the deceleration value is directly given to the deceleration control device (EBCM).

[0071] Figure 7 Schematic diagram showing the control method of the present invention under no-brake conditions.

[0072] like Figure 7 As shown in the figure, when there is no brake, the brake type is changed to no brake and no input is required to the deceleration control device (EBCM).

[0073] Next, the automatic parking brake control system of the present invention will be described.

[0074] Figure 8 It is a block diagram showing the structure of the automatic parking brake control system of the present invention.

[0075] like Figure 8 As shown, the automatic parking brake control system of the present invention includes:

[0076] Path planning module 100, plans and forms parking segment parameters;

[0077] A pre-anchor segment point set generation module 200 generates a parking segment based on the parking segment parameters and divides the parking segment into an acceleration segment and a deceleration segment;

[0078] a position determination module 300 for determining the current position of the vehicle in the parking segment based on the wheel speed sensing signal from the wheel speed sensor and the parking segment generated by the pre-anchor segment point set generation module; and

[0079] The first control module 400 is used to control the vehicle's deceleration control device as follows: if the vehicle is in the acceleration section, set the acceleration in the acceleration section so that the vehicle travels at this acceleration; if the vehicle is in the deceleration section, calculate the deceleration based on the vehicle's current speed and the remaining distance to the end of the parking segment, and control the vehicle speed in an open-loop manner based on the deceleration.

[0080] The first control module 400 further performs the following control: if the vehicle fails to stop after crossing the parking segment endpoint, the vehicle is immediately braked; if the vehicle has stopped before reaching the parking segment endpoint, the vehicle is restarted from the pre-stop point to the parking segment endpoint and decelerated using a low-speed closed-loop control after accelerating to a certain distance so that the vehicle creeps to the parking segment endpoint; if the vehicle fails to stop after creeping to the parking segment endpoint, the vehicle is immediately braked. Preferably, the low-speed closed-loop control is implemented using PID control.

[0081] Optionally, the system may further include a second control module (not shown, optional) configured to control the vehicle's steering system in a closed-loop manner to ensure the vehicle remains on the parking line. Thus, during vehicle travel, closed-loop steering control ensures the vehicle remains on the parking line. Common parking lines are typically straight lines, arcs, or spline curves, which are easily achievable with steering control.

[0082] Next, an automatic parking brake control system according to an embodiment of the present invention will be described in detail.

[0083] Figure 9 FIG2 is a schematic diagram showing the hardware structure of an automatic parking brake control system applied to a vehicle according to an embodiment of the present invention.

[0084] like Figure 9 As shown, the MCU 10 obtains vehicle speed and position sensor signals from the actual vehicle system through the CA, and sends brake control signals and steering control signals to the deceleration control device 20 and steering system 30 of the actual vehicle system, respectively. The MCU 10 integrates the automatic parking brake control system of the present invention.

[0085] Figure 10 The figure is a flow chart showing the automatic parking brake control system according to one embodiment of the present invention when it is applied to a vehicle.

[0086] like Figure 10 As shown in the figure, the path planning is first performed based on the parking space, the environment and the current vehicle body posture. After the path planning, the parking curve parameters are obtained, and the pre-anchor line segment point set is generated based on these parameters.

[0087] When parking, the trajectory is calculated based on the wheel speed sensor signal, and the current position of the vehicle in the parking segment is determined based on the existing pre-anchor segment point set.

[0088] During vehicle movement, closed-loop steering control ensures the vehicle remains on the parking line (typically a straight line, arc, or spline). Acceleration within the parking line accelerates the vehicle to a certain speed. When the vehicle travels a certain distance within the parking line, entering the deceleration phase, open-loop and closed-loop braking control are implemented using the aforementioned automatic parking brake control method.

[0089] The present invention also provides a computer-readable medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the automatic parking brake control method of the present invention.

[0090] The present invention also provides a computer device, comprising a storage module, a processor, and a computer program stored on the storage module and executable on the processor, wherein the processor implements the automatic parking brake control method of the present invention when executing the computer program.

[0091] The present invention provides a vehicle, which includes the automatic parking brake control method of the present invention.

[0092] The automatic parking brake control method and control system of the present invention utilize the method described in this solution. Regardless of the situation (premature braking, no braking, or just braking), the vehicle will eventually reach the end of the line segment. When the vehicle reaches the end of the line segment, the deceleration is directly applied to ensure that the vehicle is quickly braked to a stop. This improves parking efficiency, enhances parking accuracy, and reduces parking time.

[0093] The above examples primarily illustrate the automatic parking brake control method, automatic parking brake control system, and vehicle of the present invention. Although only certain specific embodiments of the present invention have been described, those skilled in the art will appreciate that the present invention may be implemented in numerous other forms without departing from its spirit and scope. Therefore, the examples and embodiments presented are to be considered illustrative rather than restrictive, and the present invention may encompass various modifications and substitutions without departing from the spirit and scope of the present invention as defined in the appended claims.

Claims

1. An automatic parking brake control method, characterized in that: include: The path planning step divides the pre-set parking segment into acceleration segments and deceleration segments according to a specified ratio; A first control sub-step is to set an acceleration in the acceleration section so that the vehicle travels at the acceleration; as well as The second control sub-step is to calculate the deceleration in the deceleration section according to the current speed of the vehicle and the remaining distance to the end point of the parking segment, and control the vehicle speed in an open loop according to the deceleration. The second control sub-step further includes: If the vehicle has stopped in advance before reaching the end of the parking segment, the vehicle will start again from the early braking point to the end of the parking segment and will be decelerated in a closed-loop manner after accelerating to a certain distance so that the vehicle creeps to the end of the parking segment.

2. The automatic parking brake control method according to claim 1, wherein: The second control sub-step further includes: If the vehicle fails to stop when it has crossed the end of the parking line, control is performed to bring the vehicle to an immediate stop.

3. The automatic parking brake control method according to claim 1, wherein: If the vehicle fails to stop when it creeps to the end of the parking segment, control is performed to bring the vehicle to a stop immediately.

4. The automatic parking brake control method according to claim 1, wherein: The closed loop method is implemented using PID control.

5. An automatic parking brake control system, characterized in that: include: Path planning module, plans and forms parking segment parameters; a pre-anchor segment point set generation module, which generates a parking segment based on the parking segment parameters and divides the parking segment into an acceleration segment and a deceleration segment; a position determination module for determining a current position of the vehicle in the parking segment based on a wheel speed sensor signal from a wheel speed sensor and the parking segment generated by the pre-anchor segment point set generation module; as well as The first control module is configured to control the vehicle deceleration control device as follows: if the vehicle is in the acceleration section, set the acceleration in the acceleration section so that the vehicle travels at the acceleration; if the vehicle is in the deceleration section, calculate the deceleration based on the vehicle's current speed and the remaining distance to the end point of the parking segment, and control the vehicle speed in an open-loop manner based on the deceleration; The first control module further performs the following control: if the vehicle has braked in advance before reaching the end point of the parking segment, the vehicle is restarted from the early braking point to the end point of the parking segment and the vehicle speed is decelerated in a closed-loop manner after accelerating to a certain distance so that the vehicle creeps to the end point of the parking segment.

6. The automatic parking brake control system according to claim 5, characterized in that: The first control module further performs the following control: if the vehicle fails to stop when it has crossed the end point of the parking segment, the vehicle is stopped immediately.

7. The automatic parking brake control system according to claim 5, characterized in that: The first control module further performs the following control: if the vehicle fails to stop when it creeps to the end of the parking segment, the vehicle is stopped immediately.

8. The automatic parking brake control system according to claim 5, characterized in that: The closed loop method is implemented using PID control.

9. The automatic parking brake control system according to any one of claims 5 to 8, characterized in that: Further including: The second control module is configured to control a steering system of the vehicle in a closed-loop manner so that the vehicle maintains driving on the parking line segment.

10. A computer-readable medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the automatic parking brake control method according to any one of claims 1 to 4 is implemented.

11. A computer device comprising a storage module, a processor, and a computer program stored in the storage module and executable on the processor, wherein: When the processor executes the computer program, the automatic parking brake control method according to any one of claims 1 to 4 is implemented.

12. A vehicle, characterized in that: The automatic parking brake control system includes any one of claims 5 to 9.

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