An AVH function pressure release control method, system, device and medium

Abstract

The present invention discloses a method, system, device and medium for controlling the pressure release of the AVH function. The method includes: during the activation process of the AVH function, detecting whether the vehicle has an intention to drive away; if there is an intention to drive away, obtaining the rising rate of the driving force in real time; controlling the AVH parking force to decay at the same rate as the rising rate of the driving force until it reaches zero. The present invention controls the AVH parking force to decay at the same rate as the rising rate of the driving force, improves the starting smoothness, and at the same time can also reduce unnecessary power loss and improve the vehicle energy consumption.

Description

Technical Field

[0001] The present invention belongs to the technical field of automatic parking control, and particularly relates to a method, system, device and medium for controlling pressure release of an AVH function. Background Art

[0002] AVH (Automatic Vehicle Hold) is an additional function of ESC (Electric Stability Control), aiming to reduce the intensity of the driver's parking operation. When the vehicle needs to stop temporarily during operation (such as waiting for a traffic light at an intersection or making a short stop on a slope), after the driver stops the vehicle by using the service brake, the AVH function can be activated to maintain an appropriate braking pressure in the brake pipeline, so that the vehicle can stop safely. When the driver wants to control the vehicle to drive away and steps on the accelerator pedal, AVH will control the release of the braking pressure and the vehicle can start to drive. During the whole process, the driver does not need to manually operate the parking brake system, including pulling up or releasing the handbrake or operating the EPB (Electric Parking Brake) switch.

[0003] In the existing solution, when the AVH function is activated, the braking pressure will be controlled at the pressure value corresponding to the slope where the vehicle is located, that is, the AVH parking force is controlled at the parking force level required on the slope. The electronic stability control system ESC measures the slope value α through a longitudinal acceleration sensor and calculates the vehicle downhill force F 下滑 = mgsinα, and the required AVH parking force is numerically equal to the vehicle downhill force F 下滑 , and further converted into the corresponding braking pressure for implementation according to this relationship, and the parking force F AVH is formed through pressure control, as Figure 1 shown. When it is detected that the driver intends to drive away from the vehicle, the braking pressure will be controlled to be released at a fixed rate, and the AVH parking force will also decay at the corresponding rate (during the period from T0 to T2).

[0004] As Figure 1 shown, before the T1 moment (during the period from T0 to T1) when the driving forces F 驱动 and F 下滑 reach equilibrium, F 驱动 is not yet sufficient to overcome F 下滑 , and the role of F AVH is to prevent the vehicle from rolling back. After the T1 moment (during the period from T1 to T2) when the driving forces F 驱动 and F 下滑 reach equilibrium, F 驱动 can already overcome F 下滑 , and if there is still F AVH, it will act as a drag on the vehicle's start, affecting the smoothness and comfort of the start. However, when controlling the release of brake pressure, the current technology releases it at the same fixed rate on any slope. This makes it impossible to release the brake pressure to zero at time T1 on any slope, that is, there is still F that has not been completely attenuated during the period from T1 to T2. AVH , and the greater the slope, the more F remains at T1 AVH The larger the value, the longer the T1-T2 period, which has a negative impact on the vehicle's starting smoothness. At the same time, the driving force and parking force in the T1-T2 period are unnecessarily competing, which is also not good for the vehicle's energy consumption. Summary of the invention

[0005] The purpose of the present invention is to provide an AVH function pressure release control method, system, device and medium to solve the problem that the brake pressure is released at a fixed rate and affects the vehicle starting smoothness.

[0006] The technical solution adopted by the present invention is as follows:

[0007] An AVH function pressure release control method comprises the following steps:

[0008] During the activation of the AVH function, detect whether the vehicle intends to leave;

[0009] If there is an intention to leave, the driving force increase rate is obtained in real time;

[0010] The AVH parking force is controlled to decay at the same rate as the driving force increase rate until it reaches zero.

[0011] Furthermore, the driving force rising rate is obtained in real time as follows:

[0012]

[0013] Where Δt is the sampling period, K i is the driving force rising rate of the ith cycle, F 驱动i is the driving force of the ith cycle, F 驱动i-1 is the driving force of the i-1th cycle.

[0014] Furthermore, the AVH parking force is controlled to decay at the same rate as the driving force increase rate as follows:

[0015] AVH parking force F per cycle AVH The target value is calculated as follows:

[0016] F AVHi+1 =F AVHi -K i *Δt

[0017] Where Δt is the sampling period, K iis the driving force rising rate in the i-th cycle, F AVHi is the AVH parking force in the i-th cycle, F AVHi+1 is the AVH parking force in the (i + 1)-th cycle;

[0018] The AVH parking force F AVH and the braking pressure P have the following relationship:

[0019] F AVHi+1 = 2P i+1 * C

[0020] F AVHi = 2P i * C

[0021] In the formula, P i is the braking pressure in the i-th cycle, P i+1 is the braking pressure in the (i + 1)-th cycle, and C is the transfer coefficient from the braking pressure to the parking force;

[0022] The control target value of the braking pressure P in each cycle is derived as:

[0023]

[0024] The AVH parking force is controlled by controlling the braking pressure P in each cycle to decay at the same rate as the driving force rising rate.

[0025] Furthermore, the calculation method of the transfer coefficient C from the braking pressure to the parking force is as follows:

[0026]

[0027] In the formula, A1 is the cross-sectional area of the front axle brake piston; A2 is the cross-sectional area of the rear axle brake piston; μ1 is the front axle brake friction coefficient; μ2 is the rear axle brake friction coefficient; N1 is the number of front axle brake pistons; N2 is the number of rear axle brake pistons; r1 is the effective action radius of the front axle brake disc; r2 is the effective action radius of the rear axle brake disc; R1 is the rolling radius of the front axle wheel; R2 is the rolling radius of the rear axle wheel.

[0028] An AVH function pressure release control system includes:

[0029] A departure intention detection module, which is used to detect whether the vehicle has a departure intention during the activation of the AVH function;

[0030] A driving force rising rate module, which is used to obtain the driving force rising rate in real time if there is a departure intention;

[0031] A parking force control module, which is used to control the AVH parking force to decay at the same rate as the driving force rising rate until it becomes zero.

[0032] Furthermore, the driving force rising rate module obtains the driving force rising rate in real time as follows:

[0033]

[0034] where Δt is the sampling period, and K i is the driving force rising rate in the i-th period, F 驱动i is the driving force in the i-th period, and F 驱动i-1 is the driving force in the (i - 1)-th period.

[0035] Furthermore, the parking force control module controls the AVH parking force to decay at the same rate as the driving force rising rate as follows:

[0036] The target value of the AVH parking force F AVH in each period is calculated as follows:

[0037] F AVHi+1 = F AVHi - K i *Δt

[0038] where Δt is the sampling period, and K i is the driving force rising rate in the i-th period, F AVHi is the AVH parking force in the i-th period, and F AVHi+1 is the AVH parking force in the (i + 1)-th period;

[0039] The relationship between the AVH parking force F AVH and the braking pressure P is:

[0040] F AVHi+1 = 2P i+1 *C

[0041] F AVHi = 2P i *C

[0042] where P i is the braking pressure in the i-th period, P i+1 is the braking pressure in the (i + 1)-th period, and C is the transfer coefficient from the braking pressure to the parking force;

[0043] The control target value of the braking pressure P in each period is derived as:

[0044]

[0045] The AVH parking force is controlled to decay at the same rate as the driving force rising rate by controlling the braking pressure P in each period.

[0046] Furthermore, the calculation method of the transfer coefficient C from the braking pressure to the parking force is as follows:

[0047]

[0048] In the formula, A1 is the cross-sectional area of the front axle brake piston; A2 is the cross-sectional area of the rear axle brake piston; μ1 is the friction coefficient of the front axle brake; μ2 is the friction coefficient of the rear axle brake; N1 is the number of front axle brake pistons; N2 is the number of rear axle brake pistons; r1 is the effective acting radius of the front axle brake disc; r2 is the effective acting radius of the rear axle brake disc; R1 is the rolling radius of the front axle wheel; R2 is the rolling radius of the rear axle wheel.

[0049] An electronic device includes:

[0050] A memory for storing an executable computer program;

[0051] A processor, when executing the executable computer program stored in the memory, implements the AVH function pressure release control method described in any one of the above.

[0052] A computer-readable storage medium stores a computer program, which when executed by a processor, implements the AVH function pressure release control method described in any one of the above.

[0053] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0054] The present invention controls the AVH parking force to decay at the same rate as the driving force rising rate, improves the starting smoothness, and at the same time can also reduce unnecessary power loss and improve the vehicle energy consumption. Description of the Drawings

[0055] Figure 1 It is a schematic diagram of the parking force decay in the background art;

[0056] Figure 2 It is a schematic diagram of the parking force decay in the present invention;

[0057] Figure 3 It is a flowchart of the AVH function pressure release control method of the present invention. Detailed Embodiments

[0058] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0059] During the activation process of AVH for temporary vehicle parking, when it is detected that the driver has the intention to drive away, AVH will control the braking pressure to be released at a variable rate, that is, control the AVH parking force to decay at a variable rate. During the driving force F驱动 and F 下滑 At the moment T1 when balance is achieved, the AVH controls the parking brake pressure to be released to zero, that is, the AVH parking force decays to zero, avoiding the situation that there is still part of the AVH parking force dragging the vehicle's start after the moment T1, improving the starting smoothness, and at the same time reducing unnecessary power loss and improving the vehicle's energy consumption.

[0060] According to the rising rate of the driving force after confirming the driver's intention to drive away during the AVH activation process, the present invention controls the braking pressure to decay at a suitable variable rate, so that the AVH parking force decays in the opposite direction at the same rate as the rising rate of the driving force, as Figure 2 and Figure 3 shown, the specific scheme is as follows:

[0061] Starting from the moment T0 when the driver's intention to drive away is confirmed, the rising rate of the driving force is continuously calculated in each sampling period:

[0062]

[0063] In the formula, Δt is the sampling operation period of the controller; F 驱动i is the driving force in the i-th cycle; F 驱动i-1 is the driving force in the (i - 1)-th cycle;

[0064] F AVH needs to decay in the opposite direction at the same rate. Therefore, the target value of the AVH parking force F AVH in each cycle is calculated as follows:

[0065] F AVHi+1 = F AVHi - K i *Δt

[0066] In the formula, F AVHi is the AVH parking force in the i-th cycle; F AVHi+1 is the AVH parking force in the (i + 1)-th cycle; K i is the rising rate of the driving force in the i-th cycle;

[0067] The relationship between the AVH parking force F AVH and the braking pressure P is:

[0068] F AVHi+1 = 2P i+1 *C

[0069] F AVHi = 2P i *C

[0070]

[0071] In the formula, P i is the AVH braking pressure in the i-th cycle; Pi+1 is the AVH braking pressure for the (i + 1)-th cycle; C is the transfer coefficient from braking pressure to parking force; A1 is the piston cross-sectional area of the front axle brake; A2 is the piston cross-sectional area of the rear axle brake; μ1 is the friction coefficient of the front axle brake; μ2 is the friction coefficient of the rear axle brake; N1 is the number of pistons of the front axle brake; N2 is the number of pistons of the rear axle brake; r1 is the effective action radius of the front axle brake disc; r2 is the effective action radius of the rear axle brake disc; R1 is the rolling radius of the front axle wheel; R2 is the rolling radius of the rear axle wheel;

[0072] According to the above relationship derivation, the control target value of the braking pressure P for each cycle is:

[0073]

[0074] AVH will perform braking pressure release control according to the above logic and strategy, and finally at the moment T1 when the driving forces F 驱动 and F 下滑 reach balance, the braking pressure is released to zero, the AVH parking force decays to zero, and the vehicle starts smoothly.

[0075] The present invention also provides an AVH function pressure release control system, including:

[0076] A departure intention detection module, configured to detect whether the vehicle has a departure intention during the activation of the AVH function;

[0077] A driving force rising rate module, configured to, if there is a departure intention, obtain the driving force rising rate in real time;

[0078] A parking force control module, configured to control the AVH parking force to decay at the same rate as the driving force rising rate until it reaches zero.

[0079] Further, the driving force rising rate module obtains the driving force rising rate in real time as follows:

[0080]

[0081] In the formula, Δt is the sampling period, K i is the driving force rising rate of the i-th cycle, F 驱动u is the driving force of the i-th cycle, F 驱动i-1 is the driving force of the (i - 1)-th cycle.

[0082] Further, the parking force control module controls the AVH parking force to decay at the same rate as the driving force rising rate as follows:

[0083] The target value of the AVH parking force F AVH for each cycle is calculated as follows:

[0084] F AVHi+1 = FAVHi -K i *Δt

[0085] Where Δt is the sampling period, and K i is the driving force rising rate in the i-th period, and F AVHi is the AVH parking force in the i-th period, and F AVHi+1 is the AVH parking force in the (i + 1)-th period;

[0086] The relationship between the AVH parking force F AVH and the braking pressure P is:

[0087] F AVHi+1 = 2P i+1 *C

[0088] F AVHi = 2P i *C

[0089] Where P i is the braking pressure in the i-th period, and P i+1 is the braking pressure in the (i + 1)-th period, and C is the transfer coefficient from the braking pressure to the parking force;

[0090] The control target value of the braking pressure P for each period is derived as:

[0091]

[0092] By controlling the braking pressure P for each period, the AVH parking force is controlled to decay at the same rate as the driving force rising rate.

[0093] Furthermore, the calculation method of the transfer coefficient C from the braking pressure to the parking force is as follows:

[0094]

[0095] Where A1 is the piston cross-sectional area of the front axle brake; A2 is the piston cross-sectional area of the rear axle brake; μ1 is the friction coefficient of the front axle brake; μ2 is the friction coefficient of the rear axle brake; N1 is the number of pistons of the front axle brake; N2 is the number of pistons of the rear axle brake; r1 is the effective action radius of the front axle brake disc; r2 is the effective action radius of the rear axle brake disc; R1 is the rolling radius of the front axle wheel; R2 is the rolling radius of the rear axle wheel.

[0096] The present invention also provides an electronic device, including:

[0097] A memory for storing an executable computer program;

[0098] A processor for implementing the AVH function pressure release control method described in any one of the above when executing the executable computer program stored in the memory.

[0099] The present invention also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the AVH function pressure release control method described in any one of the above.

[0100] In summary, the present invention can improve the starting smoothness and comfort of the vehicle after AVH activation, and at the same time improve the vehicle energy consumption.

[0101] It should be noted that the sequence numbers of the steps in the above embodiments do not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of the present application.

[0102] It should be pointed out that according to the needs of implementation, each step / component described in the present application can be split into more steps / components, or two or more steps / components or partial operations of steps / components can be combined into new steps / components to achieve the purpose of the present invention.

[0103] Those skilled in the art can easily understand that the above are only the preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An AVH function pressure release control method, characterized in that It includes the following steps: During the activation of the AVH function, detect whether the vehicle has an intention to drive away; If there is an intention to drive away, obtain the rising rate of the driving force in real time; Control the AVH parking force to decay at the same rate as the rising rate of the driving force until the AVH parking force becomes zero; Among them, controlling the AVH parking force to decay at the same rate as the rising rate of the driving force is as follows: The parking force F of each cycle of AVH AVH The target value is calculated as follows: F AvHi+1 = F AVHi - K i * Δt where Δt is the sampling period, K i is the driving force rising rate in the i-th cycle, F AVHi is the AVH parking force in the i-th cycle, F AVHi+1 is the AVH parking force in the (i + 1)-th cycle; AVH parking force F AVH The relationship with the braking pressure P is as follows: F AVHi+1 = 2P i+1 * C F AVHi = 2P i * C where P i is the braking pressure in the i-th cycle, and P i+1 is the braking pressure in the (i + 1)-th cycle, and C is the transmission coefficient from the braking pressure to the parking force; Derive the control target value of the braking pressure P for each cycle as: Control the AVH parking force to decay at the same rate as the rising rate of the driving force by controlling the braking pressure P for each cycle.

2. The AVH function pressure release control method according to claim 1, wherein Obtain the rising rate of the driving force in real time as follows: where Δt is the sampling period, and K i is the driving force rising rate in the i-th cycle, F 驱动i is the driving force in the i-th cycle, F 驱动i-1 is the driving force in the (i - 1)-th cycle.

3. The AVH function pressure release control method according to claim 1, wherein The calculation method of the transfer coefficient C from the braking pressure to the parking force is as follows: In the formula, A1 is the piston cross-sectional area of the front axle brake; A2 is the piston cross-sectional area of the rear axle brake; μ1 is the friction coefficient of the front axle brake; μ2 is the friction coefficient of the rear axle brake; N1 is the number of pistons of the front axle brake; N2 is the number of pistons of the rear axle brake; r1 is the effective action radius of the front axle brake disc; r2 is the effective action radius of the rear axle brake disc; R1 is the rolling radius of the front axle wheel; R2 is the rolling radius of the rear axle wheel.

4. An AVH function pressure release control system, characterized in that, It includes: A driving-away intention detection module, which is used to detect whether the vehicle has an intention to drive away during the activation of the AVH function; A driving force rising rate module, which is used to obtain the rising rate of the driving force in real time if there is an intention to drive away; A parking force control module, which is used to control the AVH parking force to decay at the same rate as the rising rate of the driving force until it becomes zero; Among them, controlling the AVH parking force to decay at the same rate as the rising rate of the driving force is as follows: The AVH parking force F for each cycle AVH The target value is calculated as follows: F AVHi+1 = F AVHi - K i * Δt where Δt is the sampling period, and K i is the driving force rising rate in the i-th cycle, and F AVHi is the AVH parking force in the i-th cycle, and F AVHi+1 is the AVH parking force in the (i + 1)-th cycle; AVH parking force F AVH The relationship with the braking pressure P is as follows: F AVHi+1 = 2P i+1 * C F AVHi = 2P i * C Where P i is the braking pressure in the i-th cycle, and P i+1 is the braking pressure in the (i + 1)-th cycle, and C is the transfer coefficient from the braking pressure to the parking force; Derive the control target value of the braking pressure P for each cycle as: Control the AVH parking force to decay at the same rate as the rising rate of the driving force by controlling the braking pressure P for each cycle.

5. The AVH function pressure release control system according to claim 4, characterized in that The driving force rising rate module obtains the rising rate of the driving force in real time as follows: where Δt is the sampling period, and K i is the driving force rising rate in the i-th cycle, F 驱动i is the driving force in the i-th cycle, F 驱动i-1 is the driving force in the (i - 1)-th cycle.

6. The AVH function pressure release control system according to claim 4, wherein The calculation method of the transfer coefficient c from the braking pressure to the parking force is as follows: In the formula, A1 is the piston cross-sectional area of the front axle brake; A2 is the piston cross-sectional area of the rear axle brake; μ1 is the friction coefficient of the front axle brake; μ2 is the friction coefficient of the rear axle brake; N1 is the number of pistons of the front axle brake; N2 is the number of pistons of the rear axle brake; r1 is the effective action radius of the front axle brake disc; r2 is the effective action radius of the rear axle brake disc; R1 is the rolling radius of the front axle wheel; R2 is the rolling radius of the rear axle wheel.

7. An electronic device, characterized in that, It includes: A memory, which is used to store an executable computer program; A processor, which is used to implement the AVH function pressure release control method described in any one of claims 1 to 3 when executing the executable computer program stored in the memory.

8. A computer-readable storage medium, characterized in that, A computer program is stored, which is used to implement the AVH function pressure release control method described in any one of claims 1 to 3 when executed by a processor.

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