CN-117068118-B - Target brake pressure determining method, parking method, system, equipment and medium

CN117068118BCN 117068118 BCN117068118 BCN 117068118BCN-117068118-B

Abstract

The application relates to a target brake pressure determining method, a parking method, a system, equipment and a medium, wherein the target brake pressure determining method comprises the following steps: the method comprises the steps of obtaining parking pressure of a vehicle, mass information of the whole vehicle, current attachment coefficient information and gradient information of a road surface where the vehicle is located at a plurality of historical sampling time points and current time points, obtaining wheel speeds of all wheels at two different time points and corresponding time points if the parking pressure is larger than 0, determining a motion state of the vehicle according to the wheel speeds of all the wheels at the two different time points and the corresponding time points, and determining target braking pressure based on the motion state, the current attachment coefficient information, the mass information of the whole vehicle, gradient information of the road surface where a plurality of historical sampling time points are located and gradient information of the road surface where the current time points are located.

Inventors

LIU CHUAN
YU BIN

Assignees

重庆长安汽车股份有限公司

Dates

Publication Date: 20260508
Application Date: 20230829

Claims (8)

1. A target brake pressure determination method, characterized in that the target brake pressure determination method comprises: Acquiring parking pressure of a vehicle, whole vehicle quality information, current attachment coefficient information and gradient information of a road surface where the vehicle is located at a plurality of historical sampling time points and current time points; if the parking pressure is greater than 0, acquiring wheel speeds of all wheels at two different time points and corresponding time points; Determining the motion state of the vehicle according to the wheel speeds of all wheels at two different time points and corresponding time points, wherein the motion state comprises a stationary state and a non-stationary state; The method comprises the steps of obtaining a plurality of historical gradient information of a road surface where a plurality of historical sampling time points are located, obtaining the processed historical gradient information if the motion state of a vehicle is in a static state, confirming a gradient average value according to the processed historical gradient information, confirming a minimum target braking pressure based on the current attachment coefficient information, the whole vehicle mass information, the gradient average value and a preset mapping relation among the attachment coefficient, the whole vehicle mass, the gradient average value and the minimum target braking pressure, and confirming the minimum target braking pressure as the target braking pressure; If the motion state of the vehicle is determined to be in a non-stationary state, determining a hill-hold target brake pressure based on current attachment coefficient information, whole vehicle mass information, gradient information of a road surface where a current time point is located, an attachment coefficient, a whole vehicle mass, a preset mapping relation between gradient and the hill-hold target brake pressure, wherein the hill-hold target brake pressure is greater than a minimum target brake pressure, and determining the hill-hold target brake pressure as a target brake pressure.
2. The target brake pressure determination method according to claim 1, wherein determining the motion state of the vehicle includes: determining the acceleration of the corresponding wheel according to the wheel speeds of the wheels at two different time points and the corresponding time points; Based on the accelerations of all the wheels, the motion state of the vehicle is determined.
3. The target brake pressure determination method according to claim 2, wherein determining the motion state of the vehicle includes: if the acceleration of all the wheels is 0, determining the motion state of the vehicle to be in a static state; If the acceleration of one of the wheels is greater than 0 or less than 0, the motion state of the vehicle is determined to be in a non-stationary state.
4. A parking method, characterized in that the parking method comprises: Acquiring parking pressure of a vehicle, whole vehicle quality information, current attachment coefficient information and gradient information of a road surface where the vehicle is located at a plurality of historical sampling time points and current time points; if the parking pressure is greater than 0, all gradient information is effective, and wheel speeds of all wheels at two different time points and corresponding time points are obtained; Determining the motion state of the vehicle according to the wheel speeds of all wheels at two different time points and corresponding time points, wherein the motion state comprises a stationary state and a non-stationary state; The method comprises the steps of obtaining a plurality of historical gradient information of a road surface where a plurality of historical sampling time points are located, obtaining the processed historical gradient information if the motion state of a vehicle is in a static state, confirming a gradient average value according to the processed historical gradient information, confirming a minimum target braking pressure based on the current attachment coefficient information, the whole vehicle mass information, the gradient average value and a preset mapping relation among the attachment coefficient, the whole vehicle mass, the gradient average value and the minimum target braking pressure, and confirming the minimum target braking pressure as the target braking pressure; If the motion state of the vehicle is determined to be in a non-stationary state, determining a hill-hold target brake pressure based on current attachment coefficient information, whole vehicle mass information, gradient information of a road surface where a current time point is located, an attachment coefficient, a whole vehicle mass, a preset mapping relation between gradient and the hill-hold target brake pressure, wherein the hill-hold target brake pressure is greater than a minimum target brake pressure; and controlling the vehicle to park according to the target brake pressure.
5. A target brake pressure determination system, the target brake pressure determination system comprising: the first acquisition module is configured to acquire parking pressure of the vehicle, whole vehicle quality information, current attachment coefficient information and gradient information of a road surface where the vehicle is located at a plurality of historical sampling time points and current time points; The second acquisition module is configured to acquire wheel speeds of all wheels at two different time points and corresponding time points if the parking pressure is greater than 0; A first determining module configured to determine a motion state of the vehicle according to wheel speeds of all wheels at two different time points and corresponding time points, wherein the motion state comprises a stationary state and a non-stationary state; The second determining module is configured to filter gradient information of a road surface where a plurality of historical sampling time points are located to obtain a plurality of processed historical gradient information if the motion state of the vehicle is in a static state, confirm gradient average value according to the plurality of processed historical gradient information, determine minimum target braking pressure based on preset mapping relation among the current attachment coefficient information, the whole vehicle mass information, the gradient average value and the attachment coefficient, the whole vehicle mass, the gradient average value and the minimum target braking pressure, determine the minimum target braking pressure as target braking pressure, and determine the ramp parking target braking pressure to be greater than the minimum target braking pressure based on preset mapping relation among the current attachment coefficient information, the whole vehicle mass information, the gradient information of the road surface where the current time points are located and the attachment coefficient, the whole vehicle mass, the gradient and the ramp parking target braking pressure if the motion state of the vehicle is determined to be in a non-static state.
6. A parking system, the parking system comprising: the first acquisition module is configured to acquire parking pressure of the vehicle, whole vehicle quality information, current attachment coefficient information and gradient information of a road surface where the vehicle is located at a plurality of historical sampling time points and current time points; The second acquisition module is configured to acquire wheel speeds of all wheels at two different time points and corresponding time points if the parking pressure is greater than 0; A first determining module configured to determine a motion state of the vehicle according to wheel speeds of all wheels at two different time points and corresponding time points, wherein the motion state comprises a stationary state and a non-stationary state; The system comprises a first determining module, a second determining module, a ramp parking target braking pressure determining module and a ramp parking target braking pressure determining module, wherein the first determining module is used for determining the current attachment coefficient information, the whole vehicle mass information, the gradient average value and the attachment coefficient, determining the minimum target braking pressure based on the current attachment coefficient information, the whole vehicle mass, the preset mapping relation between the gradient average value and the minimum target braking pressure, and determining the minimum target braking pressure as the target braking pressure; And the control module is configured to control the vehicle to park according to the target braking pressure.
7. An electronic device, the electronic device comprising: One or more processors; storage means for storing one or more programs that, when executed by the one or more processors, cause the electronic device to implement the method of any of claims 1-4.
8. A computer readable storage medium, having stored thereon a computer program which, when executed by a processor of a computer, causes the computer to perform the method of any of claims 1-4.

Description

Target brake pressure determining method, parking method, system, equipment and medium Technical Field The invention relates to the technical field of intelligent control, in particular to a target braking pressure determining method, a parking method, a system, equipment and a medium. Background An automatic parking system (AVH) is an automatically controlled driver assistance system, which aims to provide a more comfortable and safer driving experience for the driver, and is particularly suitable for uphill and downhill road conditions. An automatic parking system coverage scenario in a broad sense is typically a vehicle braking to a stationary state, a vehicle remaining stationary for a long period of time, and a vehicle driving off from a stationary state. When the driver applies the brake pedal pressure to make the moving vehicle stationary, the automatic parking system detects that the vehicle is stationary and then activates, the vehicle is output and kept after arbitration between the pedal pressure applied by the current driver and the calculated target brake pressure, and the vehicle is ensured to be stably kept in a stationary state. The automatic parking system operation sequence is shown in fig. 1, and in an ideal simulation environment, the driver drives the vehicle to brake from the time t 0 to the time t 2, the vehicle is completely stationary, and the automatic parking system should jump from the inactive state to the active state. Since the brake pressure applied by the driver has slowed the vehicle to rest and is maintained, the brake pressure at this time may remain fixed and not slip. In reality, however, the relationship of the wheels to the ground is relatively complex. In order to avoid larger pitching shaking when the vehicle brakes to a static state, commonly called a 'brake nodding phenomenon', from the perspective of a driver, the riding comfort is affected, the driver gradually reduces the braking pressure when the vehicle approaches to a static state, and moderately increases the braking pressure when the vehicle is completely static so as to resist the idling torque of a driving end, thereby realizing that the vehicle is kept in the static state. Based on the above, the state recognition of the automatic parking system will generally enter an active state (as shown at time t 0 to time t 2 in fig. 1) before the vehicle has been completely stationary due to the relationship between the vehicle and the ground. At this time, the driver brake pressure is grasped, and in order to prevent the vehicle from slipping, a redundant pressure is superimposed on the vehicle brake pressure, and the vehicle brake pressure is used as a target pressure (i.e., a target brake pressure) output from the automatic parking system. Although the automatic parking function is realized, the braking smoothness and the comfort of the vehicle are negatively affected under certain working conditions, so that the output target braking pressure is not a fixed constant value when the automatic parking system is activated, and the dynamic adjustment is realized. In the related art, through the dynamic adjustment of the unlocking pressure slope limit value when the vehicle is accelerated and driven away from the parking state activated by the automatic parking system under different gradient conditions, the driving experience is improved. However, the target braking pressure when the vehicle enters the automatic parking system activation state is not dynamically adjusted, and the use experience of the user is poor. Disclosure of Invention The invention aims to provide a target brake pressure determining method for improving the use experience of a user, a target brake pressure determining system, a parking method, a parking system, an electronic device and a computer readable storage medium. In order to solve the technical problems, the technical scheme of the application is as follows: In a first aspect, the present application provides a target brake pressure determining method including: Acquiring parking pressure of a vehicle, parking pressure of the vehicle, whole vehicle quality information, current attachment coefficient information and gradient information of a road surface where the vehicle is located at a plurality of historical sampling time points and current time points; if the parking pressure is greater than 0, acquiring wheel speeds of all wheels at two different time points and corresponding time points; determining the motion state of the vehicle according to the wheel speeds of all the wheels at two different time points and the corresponding time points; And determining the target braking pressure based on the motion state, the current attachment coefficient information, the whole vehicle mass information, the gradient information of the road surface where a plurality of historical sampling time points are located and the gradient information of the road surface where the current time points ar