Braking force output method and device, vehicle and storage medium

Abstract

The invention discloses a braking force output method and device, a vehicle and a storage medium, and belongs to the technical field of vehicles. Comprising the steps that under the condition that a first vehicle is braked and a brake pedal of the first vehicle is released, a braking system of the first vehicle is controlled to output reference braking force, and first braking force of the first vehicle is determined based on the vehicle mass of the first vehicle, target torque and the gradient of the position where the first vehicle is located; based on the environment information of the position where the first vehicle is located, the braking force safety coefficient of the first vehicle is determined, and the braking force safety coefficient is used for improving the parking safety of the first vehicle; on the basis of the reference braking force, the first braking force, the gradient and the braking force safety coefficient, the braking force output by the braking system is reduced under the condition that the first vehicle is kept static. Therefore, by reducing the braking force output by the braking system, the vehicle can be parked by using less electric energy, so that the effect of saving the electric energy under the condition of ensuring the parking safety is achieved.

Description

Technical Field

[0001] The present application relates to the field of vehicle technology, and in particular to a braking force output method, device, vehicle and storage medium. Background Art

[0002] With the development of technology, more and more functions are designed in vehicles, which provide great convenience for drivers. For example, the automatic parking function allows the user to release the brake pedal after stepping on the brake, and the vehicle can obtain braking force by itself, thus achieving automatic parking.

[0003] In the related art, after the driver steps on the brakes, the vehicle will obtain the maximum braking force when the driver steps on the brake pedal, and then apply the maximum braking force to the wheels of the vehicle to ensure that the vehicle can automatically stop.

[0004] Generally, the braking force is obtained by the torque output by the servo motor of the vehicle's brake-by-wire system. In this way, in the above-mentioned method of controlling the parking of the vehicle, the motor will output a large torque, which will waste the vehicle's electrical energy, resulting in the vehicle's electrical resources not being fully utilized. Summary of the invention

[0005] The present application provides a braking force output method, device, vehicle and storage medium, which can reduce the braking force output by the braking system, so as to save the electric energy of the vehicle while ensuring parking safety. The technical solution is as follows:

[0006] In a first aspect, a braking force output method is provided, the method comprising:

[0007] When the first vehicle is braked and the brake pedal of the first vehicle is released, the brake system of the first vehicle is controlled to output a reference braking force and a first braking force of the first vehicle is determined based on the vehicle mass of the first vehicle, the target torque and the slope of the position of the first vehicle, wherein the reference braking force is the maximum braking force output by the brake system during the braking of the first vehicle, the target torque is the torque output when the first vehicle is in an idle state, and the first braking force is the theoretical braking force required for the first vehicle to be parked at the position;

[0008] determining a braking force safety factor of the first vehicle based on environmental information of the location of the first vehicle, wherein the braking force safety factor is used to improve parking safety of the first vehicle;

[0009] Based on the reference braking force, the first braking force, the slope, and the braking force safety factor, the braking force output by the braking system is reduced while keeping the first vehicle stationary.

[0010] In the present application, when the first vehicle is stopped and the brake pedal of the first vehicle is released, the braking system of the first vehicle is controlled to output a reference braking force and the first braking force of the first vehicle is determined based on the vehicle mass of the first vehicle, the target torque and the slope of the position of the first vehicle, that is, the theoretical braking force required for the first vehicle to park at the position is first determined. Then, based on the environmental information of the position of the first vehicle, the braking force safety factor of the first vehicle is determined, so that the parking safety of the first vehicle can be improved through the braking force safety factor. Finally, based on the reference braking force, the first braking force, the slope and the braking force safety factor, the braking force output by the braking system is reduced while keeping the first vehicle stationary. In this way, by reducing the braking force output by the braking system, the vehicle can use less electrical energy to keep parked, thereby achieving the effect of saving electrical energy while ensuring parking safety.

[0011] Optionally, determining the first braking force of the first vehicle based on the vehicle mass of the first vehicle, the target torque, and the slope of the position of the first vehicle includes:

[0012] Determine the sliding force of the first vehicle at the location based on the vehicle mass of the first vehicle and the slope; determine the target driving force based on the target torque, the transmission ratio of the first vehicle and the wheel radius; when the first vehicle is in an uphill state, determine the absolute value of the difference between the sliding force and the target driving force as the first braking force; when the first vehicle is in a downhill state, determine the absolute value of the sum of the sliding force and the target driving force as the first braking force;

[0013] Alternatively, based on the vehicle mass of the first vehicle and the slope, the sliding force of the first vehicle at the current position is determined; based on the target torque, the transmission ratio of the first vehicle and the wheel radius, the target driving force is determined; when the first vehicle is in an uphill state, the absolute value of the difference between the sliding force and the target driving force is determined to obtain a first value, and the product of the first value and a parking coefficient is determined as the first braking force; when the first vehicle is in a downhill state, the absolute value of the sum of the sliding force and the target driving force is determined to obtain a second value, and the product of the second value and the parking coefficient is determined as the first braking force, and the parking coefficient is determined based on the load and / or wind resistance in the first vehicle.

[0014] Optionally, the environmental information includes a slope at a location of the first vehicle, a relative distance between the first vehicle and a second vehicle, and an estimated collision time, and determining a braking force safety factor of the first vehicle based on the environmental information at the location of the first vehicle includes:

[0015] When the slope is less than a first slope threshold and / or the expected collision time is greater than a first time threshold, a braking force safety factor of the first vehicle is obtained from a target correspondence relationship based on the slope, the relative distance and the expected collision time.

[0016] Optionally, the method further comprises:

[0017] When the slope is greater than or equal to the first slope threshold and / or the estimated collision time is less than or equal to the first time threshold, the braking system is controlled to output the first braking force.

[0018] Optionally, reducing the braking force output by the braking system based on the reference braking force, the first braking force, the slope, and the braking force safety factor while keeping the first vehicle stationary includes:

[0019] Based on the reference braking force, the first braking force and the slope, a multi-wheel braking force is reduced to obtain a second braking force, wherein the second braking force is a braking force that causes the wheel speed sensor of the first vehicle to start collecting a pulse signal during the braking force reduction process, and the pulse signal is an electrical signal generated when a gear rotor fixed on a wheel of the first vehicle rotates;

[0020] The braking system is controlled to output a braking force based on the second braking force, the reference braking force, and the braking force safety factor.

[0021] Optionally, the reducing the multi-wheel braking force based on the reference braking force, the first braking force and the slope to obtain the second braking force includes:

[0022] For the first wheel braking force reduction in the multi-wheel braking force reduction, the reference braking force is subtracted from the preset braking force to obtain the braking force after the first wheel braking force is reduced;

[0023] For the i-th wheel braking force reduction in the multi-wheel braking force reduction, when the slope is less than the second slope threshold, the braking force after the i-1-th wheel braking force reduction is subtracted from the preset braking force to obtain the braking force after the i-th wheel braking force reduction, until the wheel speed sensor of the first vehicle starts to collect pulse signals; the braking force at which the wheel speed sensor starts to collect pulse signals is determined as the second braking force, where i is an integer greater than or equal to 2;

[0024] When the slope is greater than or equal to the second slope threshold and less than the first slope threshold, the braking force after the i-1th wheel is reduced is subtracted from the preset braking force to obtain the braking force after the i-th wheel is reduced; after the braking force of multiple wheels is reduced to the first braking force, if the wheel speed sensor does not collect a pulse signal, the first braking force is determined to be the second braking force, and the second slope threshold is less than the first slope threshold.

[0025] Optionally, controlling the braking system to output the braking force based on the second braking force, the reference braking force and the braking force safety factor includes:

[0026] Multiplying the second braking force by the braking force safety factor to obtain a target braking force;

[0027] The brake system is controlled to output a smaller braking force between the target braking force and the reference braking force.

[0028] In a second aspect, a braking force output device is provided, the device comprising:

[0029] a first determination module, configured to control the braking system of the first vehicle to output a reference braking force and determine a first braking force of the first vehicle based on the vehicle mass of the first vehicle, a target torque, and a slope of a position of the first vehicle when the first vehicle is braked and the brake pedal of the first vehicle is released, wherein the reference braking force is a maximum braking force output by the braking system during the braking of the first vehicle, the target torque is a torque output when the first vehicle is in an idle state, and the first braking force is a theoretical braking force required for the first vehicle to be parked at the position;

[0030] a second determining module, configured to determine a braking force safety factor of the first vehicle based on environmental information of a location of the first vehicle, wherein the braking force safety factor is used to improve parking safety of the first vehicle;

[0031] A braking force reduction module is used to reduce the braking force output by the braking system based on the reference braking force, the first braking force, the slope and the braking force safety factor while keeping the first vehicle stationary.

[0032] Optionally, the first determining module is used to:

[0033] Determine the sliding force of the first vehicle at the location based on the vehicle mass of the first vehicle and the slope; determine the target driving force based on the target torque, the transmission ratio of the first vehicle and the wheel radius; when the first vehicle is in an uphill state, determine the absolute value of the difference between the sliding force and the target driving force as the first braking force; when the first vehicle is in a downhill state, determine the absolute value of the sum of the sliding force and the target driving force as the first braking force;

[0034] Alternatively, based on the vehicle mass of the first vehicle and the slope, the sliding force of the first vehicle at the current position is determined; based on the target torque, the transmission ratio of the first vehicle and the wheel radius, the target driving force is determined; when the first vehicle is in an uphill state, the absolute value of the difference between the sliding force and the target driving force is determined to obtain a first value, and the product of the first value and a parking coefficient is determined as the first braking force; when the first vehicle is in a downhill state, the absolute value of the sum of the sliding force and the target driving force is determined to obtain a second value, and the product of the second value and the parking coefficient is determined as the first braking force, and the parking coefficient is determined based on the load and / or wind resistance in the first vehicle.

[0035] Optionally, the environmental information includes a slope of the first vehicle, a relative distance between the first vehicle and the second vehicle, and an estimated collision time, and the second determination module is used to:

[0036] When the slope is less than a first slope threshold and / or the expected collision time is greater than a first time threshold, a braking force safety factor of the first vehicle is obtained from a target correspondence relationship based on the slope, the relative distance and the expected collision time.

[0037] Optionally, the device further comprises:

[0038] A control module is used to control the braking system to output the first braking force when the slope is greater than or equal to the first slope threshold and / or the expected collision time is less than or equal to the first time threshold.

[0039] Optionally, the braking force output module is used for:

[0040] Based on the reference braking force, the first braking force and the slope, a multi-wheel braking force is reduced to obtain a second braking force, wherein the second braking force is a braking force that causes the wheel speed sensor of the first vehicle to start collecting a pulse signal during the braking force reduction process, and the pulse signal is an electrical signal generated when a gear rotor fixed on a wheel of the first vehicle rotates;

[0041] The braking system is controlled to output a braking force based on the second braking force, the reference braking force, and the braking force safety factor.

[0042] Optionally, the braking force output module is used for:

[0043] For the first wheel braking force reduction in the multi-wheel braking force reduction, the reference braking force is subtracted from the preset braking force to obtain the braking force after the first wheel braking force is reduced;

[0044] For the i-th wheel braking force reduction in the multi-wheel braking force reduction, when the slope is less than the second slope threshold, the braking force after the i-1-th wheel braking force reduction is subtracted from the preset braking force to obtain the braking force after the i-th wheel braking force reduction, until the wheel speed sensor of the first vehicle starts to collect pulse signals; the braking force at which the wheel speed sensor starts to collect pulse signals is determined as the second braking force, where i is an integer greater than or equal to 2;

[0045] When the slope is greater than or equal to the second slope threshold and less than the first slope threshold, the braking force after the i-1th wheel is reduced is subtracted from the preset braking force to obtain the braking force after the i-th wheel is reduced; after the braking force of multiple wheels is reduced to the first braking force, if the wheel speed sensor does not collect a pulse signal, the first braking force is determined to be the second braking force, and the second slope threshold is less than the first slope threshold.

[0046] Optionally, the braking force output module is used for:

[0047] Multiplying the second braking force by the braking force safety factor to obtain a target braking force;

[0048] The brake system is controlled to output a smaller braking force between the target braking force and the reference braking force.

[0049] In a third aspect, a vehicle is provided, the vehicle comprising:

[0050] A memory for storing executable program codes;

[0051] The processor is used to call and run the executable program code from the memory so that the vehicle executes the above-mentioned braking force output method.

[0052] In a fourth aspect, a computer-readable storage medium is provided, wherein the computer-readable storage medium stores a computer program, and the computer program implements the above-mentioned braking force output method when executed by a processor.

[0053] In a fifth aspect, a computer program product comprising instructions is provided, which, when executed on a computer, enables the computer to execute the steps of the above-mentioned braking force output method.

[0054] It can be understood that the beneficial effects of the second, third, fourth and fifth aspects mentioned above can be found in the relevant description of the first aspect mentioned above, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0056] Figure 1 It is a schematic diagram of an implementation environment of a braking force output method provided in an embodiment of the present application;

[0057] Figure 2 is a schematic diagram of a scenario of a braking force output method provided in an embodiment of the present application;

[0058] Figure 3 is a flow chart of a braking force output method provided in an embodiment of the present application;

[0059] Figure 4 is a schematic diagram of force analysis of a first vehicle provided in an embodiment of the present application;

[0060] Figure 5 is a flow chart of another braking force output method provided in an embodiment of the present application;

[0061] Figure 6 is a structural schematic diagram of a braking force output device provided in an embodiment of the present application;

[0062] Figure 7 It is a structural schematic diagram of a vehicle provided in an embodiment of the present application. DETAILED DESCRIPTION

[0063] In order to make the objectives, technical solutions and advantages of the present application clearer, the implementation methods of the present application will be further described in detail below with reference to the accompanying drawings.

[0064] It should be understood that the "multiple" mentioned in this application refers to two or more. In the description of this application, unless otherwise specified, " / " means or, for example, A / B can mean A or B; "and / or" in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships, for example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, in order to facilitate the clear description of the technical solution of this application, the words "first" and "second" are used to distinguish between the same items or similar items with basically the same functions and effects. Those skilled in the art can understand that the words "first" and "second" do not limit the quantity and execution order, and the words "first" and "second" do not limit them to be different.

[0065] Before describing the braking force output method provided in the embodiment of the present application, the implementation environment provided in the embodiment of the present application is described first.

[0066] Figure 1 Schematic diagram of an implementation environment of a braking force output method provided in an embodiment of the present application. Figure 1 , Figure 1 The vehicle 101 is provided with a braking system 102 and an automatic parking holding function 103 .

[0067] The brake system 102 is used to output braking force when the vehicle slows down or stops. The brake system 102 is composed of a brake pedal, a brake master cylinder, brake fluid, a brake line, a brake, a brake disc / brake drum, a brake pad / brake shoe, a brake booster, etc., which is a traditional mechanical brake.

[0068] When the driver steps on the brake pedal, the brake pedal transmits force to the brake master cylinder through mechanical or hydraulic connection. The piston in the brake master cylinder compresses the brake fluid, thus generating high pressure. The high-pressure brake fluid is transmitted to the brakes of each wheel through the brake pipe. The piston in the brake then pushes the brake pad or brake shoe to make it contact with the brake disc or brake drum, generating friction. The friction converts the vehicle's kinetic energy into heat energy, slowing down the vehicle or stopping it.

[0069] In addition, the braking system also includes an electronic parking brake system (EPB), which is equivalent to replacing the traditional mechanical hand brake or foot brake with electronic control. Generally, the vehicle 101 is provided with an EPB on / off button. When the driver presses the EPB button, a signal to activate the parking brake is sent to the ECU (Electronic Control Unit). When it is confirmed that the vehicle is stationary, the ECU drives the brake caliper through the motor, and the brake caliper applies sufficient braking force to keep the wheel stationary.

[0070] The automatic park hold function 103 is a technology that assists the driver in automatically keeping the vehicle stationary when parking, but there is no need to continuously step on the brake pedal. The automatic park hold function 103 is widely used in scenes such as waiting for traffic lights and starting on a slope. Generally, an on / off button for the automatic park hold function 103 is provided on the vehicle. When the driver presses the on button of the automatic park hold function 103, the automatic park hold function 103 can be activated. Later, when the driver steps on the brake pedal and stops the vehicle completely, and then releases the brake pedal, the system will automatically detect and keep the vehicle stationary through the automatic park hold function. The driver can start again by lightly stepping on the accelerator pedal.

[0071] The working principle of the automatic park hold function 103: When the driver steps on the brake pedal and brings the vehicle to a complete stop, the wheel speed sensor detects that all wheels of the vehicle have stopped rotating. At the same time, the master cylinder detects that there is pressure on the brake pedal, and it is considered that the brake system has been fully braked. When the brake pedal is released later, when the automatic park hold function 103 is turned on, the ECU sends a parking signal to the EPB. Generally, the EPB is activated immediately when the driver releases the brake pedal, so that the EPB can drive the caliper through the motor to apply sufficient braking force (generally the maximum braking force when the driver steps on the brake pedal) to keep the vehicle stationary.

[0072] In the embodiment of the present application, the braking system 102 is mainly used to brake the vehicle 101. The automatic parking holding function 103 is mainly used to park the vehicle 101 by using the braking force output method provided in the embodiment of the present application when the vehicle 101 stops.

[0073] The application scenarios of the embodiments of the present application are further described.

[0074] The braking force output method provided in the embodiment of the present application can be applied to the scene where the vehicle needs to be parked automatically when it stops. For example, the braking force output method provided in the embodiment of the present application can be applied to the scene where the vehicle is waiting for a red light, or can also be applied to the scene where the vehicle is parked on a slope.

[0075] For example, Figure 2 is a schematic diagram of a braking force output method provided in an embodiment of the present application. Figure 2 , Figure 2 , includes a vehicle 201 and a ramp 202 , wherein the vehicle 201 stops on the ramp 202 .

[0076] In the prior art, when the automatic parking function is used, the maximum braking force of the vehicle 201 during the braking process is obtained, and then the vehicle 201 is parked on the ramp 202 by applying the maximum braking force.

[0077] However, in reality, when the vehicle 201 is parked on the ramp 202, it may not be necessary to apply the maximum braking force. Applying a braking force less than the maximum braking force can also allow the vehicle 201 to park automatically, which will waste the vehicle's electrical energy.

[0078] To this end, an embodiment of the present application provides a braking force output method that can determine the appropriate braking force to save the vehicle's electrical energy.

[0079] Specifically, when the vehicle 201 is braked and the brake pedal of the vehicle 201 is released, the braking system of the vehicle 201 is first controlled to output a maximum braking force during the braking process, so as to control the vehicle 201 to remain stationary. Then, based on the vehicle mass of the vehicle 201, the target torque, and the slope of the location of the vehicle 201, the first braking force of the vehicle 201 is determined, that is, a theoretical braking force when the vehicle is parked at the location. Then, based on the environmental information of the location of the vehicle 201, the braking force safety factor of the vehicle 201 is determined. Finally, based on the maximum braking force, the first braking force, the slope, and the braking force safety factor during the braking process, the braking force output by the braking system is reduced.

[0080] In this way, by reducing the braking force output by the braking system, the vehicle can use less electrical energy to maintain parking, thereby achieving the effect of saving electrical energy while ensuring parking safety.

[0081] The braking force output method provided in the embodiment of the present application is explained in detail below.

[0082] Figure 3 is a flow chart of a braking force output method provided in an embodiment of the present application. The method can be applied to the ECU of a vehicle. Figure 3 , the method comprises the following steps.

[0083] Step 301: When the first vehicle is braked and the brake pedal of the first vehicle is released, the braking system of the first vehicle is controlled to output a reference braking force and the first braking force of the first vehicle is determined based on the vehicle mass of the first vehicle, the target torque and the slope of the first vehicle.

[0084] The first vehicle being braked means that the brake pedal of the first vehicle is depressed until the vehicle completely stops.

[0085] The reference braking force is the maximum braking force output by the braking system during the first vehicle being stopped. Since the maximum braking force during the stopping process can keep the vehicle stationary, the vehicle can be kept stationary by outputting the reference braking force.

[0086] The target torque is the torque output when the first vehicle is in an idle state. When the vehicle is in an idle state, the engine needs to generate enough torque to overcome internal friction and other resistances. However, this torque is small and is mainly used to maintain stable operation of the engine. Since the engine usually rotates at a fixed speed in an idle state, the target torque can also be fixed, and can usually be stored in the memory of the first vehicle in advance when the first vehicle leaves the factory.

[0087] The slope of the position of the first vehicle can be detected by an IMU (Inertial Measurement Unit) of the first vehicle.

[0088] The first braking force is a theoretical braking force required when the first vehicle is parked at the position, that is, the first braking force is a calculated braking force that can keep the first vehicle stationary at the position.

[0089] In this case, when the first vehicle is stopped and the brake pedal is released, the first vehicle's brake system is controlled to output a reference braking force, so that the vehicle can be kept stationary to avoid rolling down the slope. Then, the first braking force of the first vehicle is determined based on the vehicle mass, the target torque, and the slope, and a theoretical braking force that can keep the first vehicle stationary at the current position can be calculated, so that the braking force can be adjusted accordingly to minimize the braking force.

[0090] It is worth noting that before step 301, it is also necessary to determine whether the first vehicle is braked and whether the brake pedal is released.

[0091] Specifically, when it is detected that the brake pedal of the first vehicle is pressed, the wheel speed of the first vehicle is obtained; when the wheel speed of each wheel of the first vehicle is 0, it is determined that the first vehicle is braked; subsequently, when it is detected that the brake pedal of the first vehicle is pressed, it is determined that the first vehicle is braked and the brake pedal is released.

[0092] In this case, when the brake pedal is detected to be depressed, the wheel speed is used to determine whether the first vehicle has stopped. When the wheel speed of each wheel of the first vehicle is 0, it means that the wheels of the first vehicle are no longer rotating, and the first vehicle has stopped at this time. However, if the wheel speed of one wheel of the first vehicle is not 0, it is determined that the first vehicle has not stopped. If the brake pedal is detected to be released when the first vehicle is in a stopped state, it can be determined that the first vehicle has been stopped and the brake pedal has been released.

[0093] Optionally, based on the vehicle mass of the first vehicle, the target torque and the slope of the position of the first vehicle, the operation of determining the first braking force of the first vehicle may be implemented in the following two possible ways.

[0094] A first possible implementation method is to determine the sliding force of the first vehicle at its current position based on the vehicle mass of the first vehicle and the slope; determine the target driving force based on the target torque, the transmission ratio of the first vehicle and the wheel radius; when the first vehicle is in an uphill state, determine the absolute value of the difference between the sliding force and the target driving force as the first braking force; when the first vehicle is in a downhill state, determine the absolute value of the sum of the sliding force and the target driving force as the first braking force.

[0095] The sliding force of the first vehicle at the current position is a downward component of the weight of the first vehicle along the ramp, which is affected by the gravity.

[0096] The target driving force is a driving force when the first vehicle is in an idling state.

[0097] Since the first vehicle is on a ramp, it will be affected by various forces, so the braking force required for the first vehicle to park on the ramp is different. Gravity will generate a component force along the ramp direction on the first vehicle, which is very important for the braking of the first vehicle. In addition, when the vehicle is parked uphill or downhill, it may have torque in the idle state, which will also cause the vehicle to have a smaller driving force. Therefore, when calculating the first braking force, the sliding force of the first vehicle at the location and the target driving force of the target vehicle can be calculated.

[0098] In this way, the first braking force is calculated after the corresponding force analysis is performed, so that the first braking force can be accurately calculated.

[0099] Among them, the operation of determining the sliding force of the first vehicle at its position based on the vehicle mass of the first vehicle and the slope can be: based on the vehicle mass of the first vehicle and the slope, determine the sliding force of the first vehicle at its position by the following formula (1).

[0100] F down =mgsinθ (1)

[0101] Among them, F down is the sliding force of the first vehicle at its location, m is the mass of the first vehicle, g is the acceleration due to gravity, which is usually taken as 9.8, and θ is the slope of the first vehicle.

[0102] For example, the mass of the first vehicle is 1500 kg (kilograms), and it stops on a slope with a slope of 10° (degrees). Then the sliding force of the first vehicle at its location is: F down =mgsinθ=1500×9.8×sin(10°)=2552.63N (Newton).

[0103] The operation of determining the target driving force based on the target torque, the transmission ratio of the first vehicle and the wheel radius may be: determining the target driving force based on the target torque, the transmission ratio of the first vehicle and the wheel radius by the following formula (2).

[0104]

[0105] Among them, F static is the target driving force of the first vehicle, T is the target torque, l is the gear ratio of the first vehicle, and R is the wheel radius of the first vehicle.

[0106] For example, the target torque of the first vehicle is 150, the gear ratio is 4, and the wheel radius is 0.3 meters. Then the target driving force of the first vehicle is

[0107] It is worth noting that when the first vehicle is going uphill, the driving force of the first vehicle is upward along the slope, so the target driving force is upward along the slope. In this case, the target driving force can offset a part of the sliding force. Therefore, when the first vehicle is in an uphill state, in order to ensure that the vehicle is stationary, the absolute value of the difference between the sliding force and the target driving force can be determined as the first braking force. For example, Figure 4 This is a schematic diagram of the force analysis of the first vehicle. Figure 4 In (a), the first vehicle 401 is in an uphill state, and has an upward target driving force and a downward sliding force on the slope.

[0108] When the first vehicle is going downhill, the driving force of the first vehicle is downward along the slope, so the direction of the target driving force is downward along the slope. In this case, in order to ensure that the vehicle is stationary, the absolute value of the sum of the sliding force and the target driving force needs to be determined as the first braking force. Figure 4 In (b), the first vehicle 401 is in a downhill state, and has a downward target driving force and a downward sliding force on the slope.

[0109] In addition, when the first vehicle is in an uphill state, the operation of determining the absolute value of the difference between the downward sliding force and the target driving force as the first braking force can be achieved by the following formula (3).

[0110] F a =|F down -F static | (3)

[0111] Among them, F a The first braking force.

[0112] When the first vehicle is in a downhill state, the operation of determining the absolute value of the sum of the downward force and the target driving force as the first braking force can be achieved by the following formula (4).

[0113] F a =|F down +F static | (4)

[0114] A second possible implementation method is to determine the sliding force of the first vehicle at its current position based on the vehicle mass of the first vehicle and the slope; determine the target driving force based on the target torque, the transmission ratio of the first vehicle and the wheel radius; when the first vehicle is in an uphill state, determine the absolute value of the difference between the sliding force and the target driving force to obtain a first numerical value, and determine the product of the first numerical value and the parking coefficient as the first braking force; when the first vehicle is in a downhill state, determine the absolute value of the sum of the sliding force and the target driving force to obtain a second numerical value, and determine the product of the second numerical value and the parking coefficient as the first braking force.

[0115] The parking coefficient is determined based on the load and / or wind resistance in the first vehicle. Optionally, the parking coefficient may also be pre-calibrated by a technician.

[0116] The first vehicle needs to remain stationary at the location, and its braking force will be affected by many factors, such as the load in the first vehicle, not just the weight of the first vehicle itself, and the environment at the location (wind, road surface, etc.). Therefore, in the embodiment of the present application, a parking coefficient can be set, and the first braking force is subsequently determined based on the parking coefficient.

[0117] In this case, by setting a parking coefficient, various influencing factors can be taken into consideration when the first vehicle is parked at its position, thereby obtaining a more accurate first braking force, and further enabling the first braking force to ensure that the first vehicle remains stationary at its position.

[0118] Among them, when the first vehicle is in an uphill state, the absolute value of the difference between the sliding force and the target driving force is determined to obtain a first value, and the product of the first value and the parking coefficient is determined as the first braking force. This operation can be achieved by the following formula (5).

[0119] F a =|F down -F static |×k (5)

[0120] Among them, κ is the parking coefficient.

[0121] When the first vehicle is in a downhill state, the absolute value of the sum of the sliding force and the target driving force is determined to obtain a second value, and the product of the second value and the parking coefficient is determined as the first braking force. This operation can be achieved by the following formula (6).

[0122] F a =|F down +F static |×k (6)

[0123] Optionally, the operation of determining the parking coefficient may be: obtaining the drag coefficient and frontal area of ​​the first vehicle, the wind speed, and the air density at the position of the first vehicle; determining the friction required for the first vehicle at the position based on the vehicle mass of the first vehicle, the slope, the drag coefficient and frontal area of ​​the first vehicle, the wind speed and the air density at the position of the first vehicle; determining the parking coefficient of the first vehicle based on the friction and sliding force required for the first vehicle at the position.

[0124] The frontal area of ​​the first vehicle is affected by the vehicle structure, and the drag coefficient is affected by the frontal area. Optionally, the drag coefficient and the frontal area of ​​the first vehicle may be pre-stored in a memory of the first vehicle.

[0125] A wind speed sensor may be installed on the first vehicle, and the wind speed at the location of the first vehicle may be collected through the wind speed sensor when determining the parking coefficient.

[0126] Among them, based on the vehicle mass of the first vehicle, the slope, the drag coefficient and the windward area of ​​the first vehicle, the wind speed at the location of the first vehicle and the air density, the operation of determining the friction force required for the first vehicle at the location can be: based on the vehicle mass of the first vehicle, the slope, the drag coefficient and the windward area of ​​the first vehicle, the wind speed at the location of the first vehicle and the air density, the friction force required for the first vehicle at the location is determined by the following formula (7).

[0127]

[0128] Among them, F 摩擦is the friction force required by the first vehicle at its position, ρ is the air density, υ 风 is the wind speed at the location of the first vehicle, B is the frontal area of ​​the first vehicle, C d is the drag coefficient of the first vehicle, It is the angle between the wind direction and the slope direction.

[0129] Optionally, based on the friction and sliding force required by the first vehicle at its position, the operation of determining the parking coefficient of the first vehicle may be: based on the friction and sliding force required by the first vehicle at its position, the parking coefficient of the first vehicle may be determined by the following formula (8).

[0130]

[0131] In this case, by comprehensively considering various factors, a more accurate parking coefficient can be determined, so that the first vehicle can be guaranteed to remain stationary at its position later.

[0132] Through the above step 301, the theoretical braking force required for the first vehicle to park at the current position can be determined, but the first braking force may not be small enough, so the following steps 302 and 303 can be continued to be executed.

[0133] Step 302: Based on the environmental information of the position of the first vehicle, determine the braking force safety factor of the first vehicle, where the braking force safety factor is used to improve the parking safety of the first vehicle.

[0134] The environmental information of the location of the first vehicle may include the slope of the location of the first vehicle, the relative distance between the first vehicle and the second vehicle, and the estimated collision time. The second vehicle refers to the vehicle behind or in front of the first vehicle. For example, when the first vehicle is going uphill, the vehicle following behind the first vehicle can be called the second vehicle. For another example, when the first vehicle is going downhill, the vehicle in front of the first vehicle can be called the second vehicle. The estimated collision time refers to the time from the current moment until the collision between the first vehicle and the second vehicle occurs.

[0135] The braking force safety factor can be specifically used to improve the safety factor of the first vehicle in the process of reducing the braking force. The braking force safety factor is affected by the slope, the relative distance between the first vehicle and the second vehicle, and the expected collision time. It should be understood that the greater the slope, the greater the risk of the first vehicle sliding down the slope, the greater the required braking force, and thus the greater the braking force safety factor; the smaller the relative distance between the first vehicle and the second vehicle or the smaller the expected collision time, the first vehicle cannot slide down the slope, and thus the required braking force is greater, and at this time the braking force safety factor is also greater, to ensure that the first vehicle can be completely stationary at its position.

[0136] In this case, the braking force safety factor of the first vehicle is determined based on the environmental information of the position of the first vehicle, so that the braking force safety factor can subsequently ensure that the vehicle remains completely stationary on the slope when parked at the position, thereby improving the parking safety of the first vehicle.

[0137] Optionally, the operation of step 302 may be: when the slope is less than a first slope threshold and / or the expected collision time is greater than a first time threshold, based on the slope, the relative distance between the first vehicle and the second vehicle, and the expected collision time, obtaining the braking force safety factor of the first vehicle from the target correspondence relationship.

[0138] The first slope threshold and the first time threshold can be set in advance, and the first slope threshold can be set to be smaller, and the first time threshold can be set to be larger.

[0139] The target corresponding relationship includes the corresponding relationship between the slope, the relative distance, the expected collision time and the braking force safety factor, and the target corresponding relationship includes multiple slopes, multiple relative distances, multiple expected collision times and multiple braking force safety factors. Among them, one slope, one relative distance and one expected collision time correspond to one braking force safety factor.

[0140] For example, Table 1 is an example of a target correspondence relationship. Referring to Table 1, Table 1 includes multiple slopes, multiple relative distances, multiple estimated collision times, and multiple braking force safety factors, wherein each set of slope, relative distance, and estimated collision time corresponds to a braking force safety factor. For example, if the slope is 10°, the relative distance is 10 meters, and the estimated collision time is 30 seconds, then the corresponding braking force safety factor can be determined to be 1 from Table 1 below.

[0141] Table 1

[0142] slope Relative distance Estimated time of collision Braking force safety factor 10° 10 meters 30 seconds 1 20° 20 meters 20 seconds 1.2 30° 10 meters 10 seconds 1.3 …… …… …… ……

[0143] The embodiment of the present application only uses the above Table 1 as an example to illustrate the target correspondence relationship, and does not constitute a limitation to the embodiment of the present application.

[0144] Since the braking force safety factor is a factor used to improve the safety of the first vehicle during the process of reducing the braking force, if the slope of the ramp is too large and the expected collision time is too small, the vehicle may slide down the slope if the operation of reducing the braking force is performed. Therefore, the operation of reducing the braking force cannot be performed in this case. Therefore, in the embodiment of the present application, it is arranged that the braking force safety factor is determined when the slope is less than the first slope threshold and / or the expected collision time is greater than the first time threshold.

[0145] In this case, when the slope is less than the first slope threshold and / or the estimated collision time is greater than the first time threshold, it means that the slope is small and / or the estimated collision time is large. Then, when the braking force is reduced, the risk of the first vehicle sliding down the slope is small, and therefore, the braking force can be reduced, and the braking force safety factor can be determined.

[0146] When the slope is greater than or equal to the first slope threshold and / or the expected collision time is less than or equal to the first time threshold, it means that the slope is large and / or the expected collision time is small. Then, when the braking force is reduced, the risk of the vehicle sliding down the slope is greater. Therefore, the operation of reducing the braking force cannot be performed, and there is no need to determine the braking force safety factor.

[0147] Optionally, when the slope is greater than or equal to a first slope threshold and / or the estimated collision time is less than or equal to a first time threshold, the braking system is controlled to output a first braking force.

[0148] Because when the slope is greater than or equal to the first slope threshold and / or the expected collision time is less than or equal to the first time threshold, there is a risk of the first vehicle sliding down the slope during the process of reducing the braking force, and there is even a risk of collision after sliding down the slope. Therefore, the braking force is not reduced in this case. At this time, the braking system can be directly controlled to output the first braking force, that is, the theoretical braking force required for the first vehicle to park in its current position can be output.

[0149] Optionally, when the slope is greater than or equal to a first slope threshold and / or the estimated collision time is less than or equal to a first time threshold, the braking system is controlled to output a smaller braking force between the first braking force and the reference braking force.

[0150] In this case, that is, the first braking force is compared with the reference braking force, and the braking system is subsequently controlled to output the smaller braking force between the first braking force and the reference braking force, thereby also achieving the purpose of energy saving.

[0151] Since the first braking force and the reference braking force are braking forces that can ensure that the first vehicle remains stationary at its position, when the slope is greater than or equal to the first slope threshold and / or the expected collision time is less than or equal to the first time threshold, the corresponding braking force is output by the braking system, which can ensure the safety while enabling the first vehicle to remain stationary at its position, thereby improving parking safety.

[0152] It is worth noting that before determining the braking force safety factor, it is also necessary to determine whether there is a second vehicle behind the first vehicle; when there is a second vehicle behind the first vehicle, obtain the relative distance and relative speed between the first vehicle and the second vehicle; divide the relative distance by the relative speed to obtain the estimated collision time.

[0153] Optionally, a radar may be installed on the first vehicle, and subsequently the relative distance and relative speed between the first vehicle and the second vehicle may be collected by the radar installed on the first vehicle.

[0154] In addition, the operation of determining whether there is a second vehicle behind the first vehicle can be: collecting a rear image through a camera of the first vehicle; outputting the rear image to a vehicle recognition model, processing the rear image through the vehicle recognition model, and outputting a recognition result; when the recognition result is that there is a vehicle, determining that there is a second vehicle behind the first vehicle; when the recognition result is that there is no vehicle, determining that there is no second vehicle behind the first vehicle.

[0155] The vehicle recognition model is used to identify whether there is a vehicle in the image. Optionally, the vehicle recognition model is a convolutional neural network model or other models capable of target detection, which is not limited in the embodiments of the present application. For example, the vehicle recognition model can be a YOLO (You Only Look Once) model, a Fast R-CNN (Fast Region-based Convolutional Neural Network), and the like.

[0156] In this way, by determining whether there is a second vehicle behind the first vehicle by means of a neural network model, it is possible to more conveniently determine whether there is a vehicle behind the first vehicle, thereby improving vehicle detection efficiency.

[0157] Through the above step 302, the braking force safety factor of the first vehicle in the process of reducing the braking force can be determined, so the braking force can be reduced accordingly in the subsequent process, that is, continue to execute the following step 303.

[0158] Step 303: Based on the reference braking force, the first braking force, the slope and the braking force safety factor, the braking force output by the braking system is reduced while keeping the first vehicle stationary.

[0159] In this case, the braking force output by the braking system is reduced based on the reference braking force, the first braking force, the slope and the braking force safety factor, so that the braking force of the first vehicle can be reduced while ensuring safety, so that a smaller braking force can be used to maintain the first vehicle stationary at its position, thereby achieving the purpose of saving electric energy.

[0160] Specifically, the operation of step 303 may include the following steps (1) to (2).

[0161] (1) Based on the reference braking force, the first braking force and the slope, the multi-wheel braking force is reduced to obtain the second braking force.

[0162] The second braking force is the braking force that causes the wheel speed sensor of the first vehicle to start collecting a pulse signal during the process of reducing the braking force. The pulse signal is an electrical signal generated when a gear rotor fixed on the wheel of the first vehicle rotates.

[0163] The wheel speed sensor consists of a permanent magnet, a coil and a gear rotor. The permanent magnet can generate a constant magnetic field, the coil surrounds the permanent magnet, and the gear rotor is fixed on the vehicle and rotates with the wheel.

[0164] When the gear rotor rotates, the teeth on it will periodically approach and move away from the permanent magnet. When the teeth approach the permanent magnet, the magnetic field will change, causing a changing magnetic field to be generated in the coil. This changing magnetic field will induce a voltage signal in the coil. Due to the periodic motion of the teeth, the voltage signal generated in the coil will be in the form of pulses, which is the pulse signal described in the embodiment of the present application. The wheel speed is subsequently determined based on the number of pulses.

[0165] The whole process is equivalent to collecting pulse signals based on the reference braking force, the first braking force and the slope during the process of reducing the braking force of multiple wheels. That is, a pulse signal is collected every time the braking force is reduced until a pulse signal is collected. Then the second braking force is the braking force when the pulse signal is started to be collected.

[0166] In this case, when the pulse signal is generated, it means that the gear rotor has just started to move. Therefore, the reduction of the braking force is stopped in time when the gear rotor just starts to move, so that the first vehicle will not slide down the slope and can obtain a smaller braking force. In this way, the braking force can be reduced as much as possible while ensuring safety, so that the vehicle can be parked with an appropriate braking force.

[0167] Optionally, the operation of step (1) may include the following steps (a)-step (b) or steps (a)-step (c).

[0168] (a) For the first round of braking force reduction in multiple rounds of braking force reduction, the reference braking force is subtracted from the preset braking force to obtain the braking force after the first round of braking force reduction.

[0169] The preset braking force may be set in advance, and the preset braking force may be set according to actual needs, for example, the preset braking force may be set smaller.

[0170] In this case, it is equivalent to reducing the maximum braking force by the preset braking force first to reduce the braking force. And when the preset braking force is small, the maximum braking force is first reduced by a smaller braking force to obtain the braking force after the first reduction.

[0171] (b) For the i-th wheel braking force reduction in the multi-wheel braking force reduction, when the slope is less than the second slope threshold, the braking force after the i-1-th wheel braking force reduction is subtracted from the preset braking force to obtain the braking force after the i-th wheel braking force reduction, until the wheel speed sensor of the first vehicle starts to collect pulse signals; the braking force that causes the wheel speed sensor to start collecting pulse signals is determined as the second braking force.

[0172] Among them, the second slope threshold is smaller than the first slope threshold, and the above step (b) is executed when the slope is very small, that is, when the slope is very small, the maximum braking force is gradually decreased until the wheel speed sensor collects a pulse signal.

[0173] Since the probability of the first vehicle sliding down the slope during the process of reducing the braking force is very small when the slope is very small, the braking force can be reduced until the pulse signal is collected.

[0174] In addition, for the reduction of multi-wheel braking force, the maximum braking force is actually reduced according to a certain gradient, and when the preset braking force is small, the maximum braking force is slowly reduced with a smaller gradient, so that the pulse signal can be collected more accurately during the process of braking force reduction, and the second braking force can be determined more accurately.

[0175] The following example illustrates the braking force reduction process when the slope is less than the second slope threshold.

[0176] For example, the maximum braking force is 100, the preset braking force is 5, and after the first round of braking force reduction, the braking force after the first round of braking force reduction is 95.

[0177] When the braking force of the second wheel is reduced, the braking force (95) after the braking force of the first wheel is reduced is subtracted from the preset braking force (5) to obtain the braking force (90) after the braking force of the second wheel is reduced. The wheel speed sensor of the first vehicle continuously collects pulse signals, and after the braking force of the second wheel is reduced, the wheel speed sensor does not collect pulse signals.

[0178] When the braking force of the third wheel is reduced, the braking force (90) after the braking force of the second wheel is reduced is subtracted from the preset braking force (5) to obtain the braking force (85) after the braking force of the third wheel is reduced. The wheel speed sensor of the first vehicle continuously collects pulse signals, and after the braking force of the third wheel is reduced, the wheel speed sensor does not collect pulse signals.

[0179] For the reduction of the braking force of the fourth wheel, the braking force (85) after the braking force of the third wheel is reduced is subtracted from the preset braking force (5) to obtain the braking force (80) after the braking force of the fourth wheel is reduced. The wheel speed sensor of the first vehicle continuously collects pulse signals. At this time, after the braking force of the fourth wheel is reduced, the wheel speed sensor collects a pulse signal, then the braking force reduction is stopped, and the second braking force is determined to be 80 at this time.

[0180] Optionally, when the braking force is reduced to the first braking force, the preset braking force may be appropriately reduced, and subsequently the braking force is reduced with the reduced preset braking force as a gradient.

[0181] Since the first braking force is a calculated theoretical braking force required for the vehicle to park at its current position, if the braking force is subsequently reduced too much, the probability of the first vehicle sliding down the slope will increase. Therefore, the braking force may be reduced with a smaller gradient subsequently.

[0182] Continuing with the above example, the first braking force is 80. If the braking force is reduced to 80 after the braking force of the 4th wheel is reduced, but the wheel speed sensor has not yet collected a pulse signal, then the preset braking force is reduced at this time. Assume that the preset braking force after reduction is 2.

[0183] Then, for the reduction of the braking force of the fifth wheel, the braking force (80) after the braking force of the fourth wheel is reduced minus the reduced preset braking force (2), to obtain the braking force (78) after the braking force of the fifth wheel is reduced. The wheel speed sensor of the first vehicle continuously collects pulse signals. At this time, after the braking force of the fifth wheel is reduced, the wheel speed sensor collects a pulse signal, and the braking force reduction is stopped. At this time, the second braking force is determined to be 78.

[0184] Optionally, the operation of step (b) can also be: for the i-th wheel braking force reduction in the multi-wheel braking force reduction, when the slope is less than the second slope threshold and / or the expected collision time is greater than the second time threshold, subtract the preset braking force from the braking force after the i-1-th wheel braking force is reduced to obtain the braking force after the i-th wheel braking force is reduced, until the wheel speed sensor of the first vehicle starts to collect pulse signals; the braking force that causes the wheel speed sensor to start collecting pulse signals is determined as the second braking force.

[0185] The second time threshold may be set in advance, and the second time threshold may be set according to a magnitude relationship that the second time threshold is greater than the first time threshold.

[0186] In this case, the slope is very small and / or the estimated collision time is very long. Since the probability of the first vehicle sliding down the slope is low when the slope is very small or the estimated collision time is very long, even if the first vehicle slides down the slope, it may not cause damage to the first vehicle. Therefore, the above steps can be performed when the slope is very small and / or the estimated collision time is very long.

[0187] (c) When the slope is greater than or equal to the second slope threshold and less than the first slope threshold, the braking force after the braking force of the i-1th wheel is reduced is subtracted from the preset braking force to obtain the braking force after the braking force of the i-th wheel is reduced; after the braking force of multiple wheels is reduced to the first braking force, if the wheel speed sensor does not collect a pulse signal, the first braking force is determined as the second braking force.

[0188] When the slope is greater than or equal to the second slope threshold and less than the first slope threshold, it means that the slope is slightly larger but not particularly large. In this case, after the braking force is reduced, if the braking force is reduced to the first braking force and no pulse signal is collected, the first braking force is subsequently determined as the second braking force.

[0189] Since the probability of the first vehicle rolling down the slope increases slightly when the slope is slightly larger, if the braking force has been reduced to the first braking force and the pulse signal has not been collected, further reduction of the braking force may cause rolling down the slope. Therefore, the first braking force can be determined as the second braking force.

[0190] In this case, after the multi-wheel braking force is reduced to the first braking force, if the pulse signal has not been collected, the first braking force is determined as the second braking force, which can ensure that the first vehicle does not roll down the slope.

[0191] The following example illustrates the solution executed when the slope is greater than or equal to the second slope threshold and less than the first slope threshold.

[0192] For example, the maximum braking force is 100, the first braking force is 80, the preset braking force is 5, and after the first round of braking force reduction, the braking force after the first round of braking force reduction is 95.

[0193] When the braking force of the second wheel is reduced, the braking force (95) after the braking force of the first wheel is reduced is subtracted from the preset braking force (5) to obtain the braking force (90) after the braking force of the second wheel is reduced. The wheel speed sensor of the first vehicle continuously collects pulse signals, and after the braking force of the second wheel is reduced, the wheel speed sensor does not collect pulse signals.

[0194] When the braking force of the third wheel is reduced, the braking force (90) after the braking force of the second wheel is reduced is subtracted from the preset braking force (5) to obtain the braking force (85) after the braking force of the third wheel is reduced. The wheel speed sensor of the first vehicle continuously collects pulse signals, and after the braking force of the third wheel is reduced, the wheel speed sensor does not collect pulse signals.

[0195] When the braking force of the fourth wheel is reduced, the braking force (85) after the braking force of the third wheel is reduced minus the preset braking force (5) to obtain the braking force (80) after the braking force of the fourth wheel is reduced. The wheel speed sensor of the first vehicle continuously collects pulse signals, and the wheel speed sensor has not collected pulse signals after the braking force of the fourth wheel is reduced. At this time, the first braking force (80) is determined as the second braking force.

[0196] Optionally, the operation of step (c) can also be: for the i-th wheel braking force reduction in multi-wheel braking force reduction, when the slope is greater than or equal to the second slope threshold and less than the first slope threshold and / or the expected collision time is less than the second time threshold and greater than the first time threshold, subtract the preset braking force from the braking force after the i-1-th wheel braking force is reduced to obtain the braking force after the i-th wheel braking force is reduced; after the multi-wheel braking force is reduced to the first braking force, if the wheel speed sensor does not collect a pulse signal, the first braking force is determined as the second braking force.

[0197] In this case, the slope is slightly larger and / or the estimated collision time is slightly larger. Since when the slope is slightly larger or the estimated collision time is slightly larger, if the braking force is reduced too much, the probability of the first vehicle sliding down the slope will increase, and therefore, the sliding down the slope of the first vehicle may cause damage to the first vehicle. Therefore, the above steps can be performed when the slope is greater than or equal to the second slope threshold and less than the first slope threshold and / or the estimated collision time is less than the second time threshold and greater than the first time threshold.

[0198] (2) Based on the second braking force, the reference braking force and the braking force safety factor, the braking system is controlled to output the braking force.

[0199] Since the second braking force is the braking force that just keeps the first vehicle stationary after the braking force is reduced, based on the second braking force, the reference braking force and the braking force safety factor, the braking system can be controlled to output a smaller braking force, and the braking system is controlled to output a smaller braking force while ensuring the parking safety of the first vehicle, thereby achieving the effect of saving electric energy.

[0200] Specifically, the operation of step (2) may be: multiplying the second braking force by a braking force safety factor to obtain a target braking force; and controlling the braking system to output a smaller braking force between the target braking force and the reference braking force.

[0201] In this case, by multiplying the second braking force by the braking force safety factor, a target braking force that can ensure the parking safety of the first vehicle can be obtained. Then, the smaller braking force between the target braking force and the reference braking force is selected for output, so that the braking system of the first vehicle can always output a smaller braking force while ensuring parking safety, thereby saving electric energy.

[0202] For example, the reference braking force is 100, the second braking force is 80, and the braking force safety factor is 1.

[0203] First, the second braking force (80) is multiplied by the braking force safety factor (1) to obtain a target braking force of 80. Then, the target braking force (80) is compared with the reference braking force (100), and if it is determined that the target braking force is smaller, the braking system is controlled to output the smaller target braking force (80).

[0204] For ease of understanding, now combined Figure 5 The braking force output method provided in the embodiment of the present application is exemplified. For example, Figure 5 A flowchart of another braking force output method provided in an embodiment of the present application is shown in FIG. Figure 5 , Figure 5 The process includes steps 501 to 509.

[0205] Step 501: When the first vehicle is braked and the brake pedal of the first vehicle is released, control the braking system of the first vehicle to output a reference braking force.

[0206] Step 502: Determine a first braking force of the first vehicle based on the vehicle mass of the first vehicle, the target torque, and the slope of the first vehicle.

[0207] Step 503: Determine whether the slope is less than a first slope threshold and / or whether the estimated collision time is greater than a first time threshold.

[0208] Step 504: When the slope is less than a first slope threshold and / or the estimated collision time is greater than a first time threshold, determine the braking force safety factor of the first vehicle. When the slope is greater than or equal to the first slope threshold and / or the estimated collision time is less than or equal to the first time threshold, control the braking system to output a first braking force.

[0209] Step 505: Determine whether the slope is less than a second slope threshold and / or whether the estimated collision time is greater than a second time threshold.

[0210] Step 506: When the slope is less than the second slope threshold and / or the estimated collision time is greater than the second time threshold, the reference braking force is reduced for multiple wheels until the wheel speed sensor collects a pulse signal, and the braking force at which the wheel speed sensor starts to collect the pulse signal is determined as the second braking force.

[0211] Step 507: When the slope is greater than or equal to the second slope threshold and less than the first slope threshold and / or the estimated collision time is less than or equal to the second time threshold and greater than the first time threshold, after the reference braking force has been reduced through multiple rounds of braking force, if no pulse signal is collected, the first braking force is determined as the second braking force.

[0212] Step 508: Multiply the second braking force by the braking force safety factor to obtain a target braking force.

[0213] Step 509: Control the braking system to output the smaller braking force between the target braking force and the reference braking force.

[0214] In the embodiment of the present application, when the first vehicle is stopped and the brake pedal of the first vehicle is released, the ECU controls the braking system of the first vehicle to output a reference braking force and determines the first braking force of the first vehicle based on the vehicle mass of the first vehicle, the target torque and the slope of the position of the first vehicle, that is, first determine the theoretical braking force required for the first vehicle to park at the position. Then, based on the environmental information of the position of the first vehicle, determine the braking force safety factor of the first vehicle, so that the parking safety of the first vehicle can be improved through the braking force safety factor. Finally, based on the reference braking force, the first braking force, the slope and the braking force safety factor, the braking force output by the braking system is reduced while keeping the first vehicle stationary. In this way, by reducing the braking force output by the braking system, the vehicle can use less electrical energy to keep parked, thereby achieving the effect of saving electrical energy while ensuring parking safety.

[0215] Figure 6 is a schematic diagram of a braking force output device provided in an embodiment of the present application. The braking force output device can be implemented by software, hardware or a combination of both to form part or all of a vehicle, and the vehicle can be as follows Figure 7 Vehicle shown. Figure 6 The device includes: a first determination module 601, a second determination module 602 and a braking force reduction module 603.

[0216] A first determination module 601 is used to control the braking system of the first vehicle to output a reference braking force and determine a first braking force of the first vehicle based on the vehicle mass of the first vehicle, the target torque and the slope of the first vehicle when the first vehicle is braked and the brake pedal of the first vehicle is released, wherein the reference braking force is the maximum braking force output by the braking system during the braking of the first vehicle, the target torque is the torque output when the first vehicle is in an idle state, and the first braking force is the theoretical braking force required for the first vehicle to be parked at the position where the first vehicle is located;

[0217] A second determination module 602 is used to determine a braking force safety factor of the first vehicle based on environmental information of the location of the first vehicle, where the braking force safety factor is used to improve parking safety of the first vehicle;

[0218] The braking force reducing module 603 is used to reduce the braking force output by the braking system based on the reference braking force, the first braking force, the slope and the braking force safety factor while keeping the first vehicle stationary.

[0219] Optionally, the first determining module 601 is used to:

[0220] Determine the sliding force of the first vehicle at the location based on the vehicle mass of the first vehicle and the slope; determine the target driving force based on the target torque, the transmission ratio of the first vehicle and the wheel radius; when the first vehicle is in an uphill state, determine the absolute value of the difference between the sliding force and the target driving force as the first braking force; when the first vehicle is in a downhill state, determine the absolute value of the sum of the sliding force and the target driving force as the first braking force;

[0221] Alternatively, based on the vehicle mass of the first vehicle and the slope, the sliding force of the first vehicle at the current position is determined; based on the target torque, the transmission ratio of the first vehicle and the wheel radius, the target driving force is determined; when the first vehicle is in an uphill state, the absolute value of the difference between the sliding force and the target driving force is determined to obtain a first numerical value, and the product of the first numerical value and the parking coefficient is determined as the first braking force; when the first vehicle is in a downhill state, the absolute value of the sum of the sliding force and the target driving force is determined to obtain a second numerical value, and the product of the second numerical value and the parking coefficient is determined as the first braking force, and the parking coefficient is determined based on the load and / or wind resistance in the first vehicle.

[0222] Optionally, the environmental information includes the slope of the first vehicle, the relative distance between the first vehicle and the second vehicle, and the estimated collision time. The second determination module 602 is used to:

[0223] When the slope is less than a first slope threshold and / or the estimated collision time is greater than a first time threshold, a braking force safety factor of the first vehicle is obtained from the target correspondence based on the slope, the relative distance and the estimated collision time.

[0224] Optionally, the device further comprises:

[0225] The control module is used to control the braking system to output a first braking force when the slope is greater than or equal to a first slope threshold and / or the estimated collision time is less than or equal to a first time threshold.

[0226] Optionally, the braking force output module 603 is used to:

[0227] Based on the reference braking force, the first braking force and the slope, the multi-wheel braking force is reduced to obtain a second braking force, wherein the second braking force is a braking force that causes the wheel speed sensor of the first vehicle to start collecting a pulse signal during the braking force reduction process, and the pulse signal is an electrical signal generated when a gear rotor fixed on a wheel of the first vehicle rotates;

[0228] Based on the second braking force, the reference braking force and the braking force safety factor, the braking system is controlled to output the braking force.

[0229] Optionally, the braking force output module 603 is used to:

[0230] For the first round of braking force reduction in the multiple rounds of braking force reduction, the reference braking force is subtracted from the preset braking force to obtain the braking force after the first round of braking force reduction;

[0231] For the i-th wheel braking force reduction in the multi-wheel braking force reduction, when the slope is less than the second slope threshold, the braking force after the i-1-th wheel braking force reduction is subtracted from the preset braking force to obtain the braking force after the i-th wheel braking force reduction, until the wheel speed sensor of the first vehicle starts to collect pulse signals; the braking force at which the wheel speed sensor starts to collect pulse signals is determined as the second braking force, where i is an integer greater than or equal to 2;

[0232] When the slope is greater than or equal to the second slope threshold and less than the first slope threshold, the preset braking force is subtracted from the braking force after the i-1th wheel is reduced to obtain the braking force after the i-th wheel braking force is reduced; after the braking force of multiple wheels is reduced to the first braking force, if the wheel speed sensor does not collect a pulse signal, the first braking force is determined to be the second braking force, and the second slope threshold is less than the first slope threshold.

[0233] Optionally, the braking force output module 603 is used to:

[0234] Multiply the second braking force by the braking force safety factor to obtain the target braking force;

[0235] The brake system is controlled to output the smaller braking force between the target braking force and the reference braking force.

[0236] In an embodiment of the present application, when the first vehicle is stopped and the brake pedal of the first vehicle is released, the braking system of the first vehicle is controlled to output a reference braking force and the first braking force of the first vehicle is determined based on the vehicle mass of the first vehicle, the target torque and the slope of the position of the first vehicle, that is, the theoretical braking force required for the first vehicle to park at the position is first determined. Then, based on the environmental information of the position of the first vehicle, the braking force safety factor of the first vehicle is determined, so that the parking safety of the first vehicle can be improved through the braking force safety factor. Finally, based on the reference braking force, the first braking force, the slope and the braking force safety factor, the braking force output by the braking system is reduced while keeping the first vehicle stationary. In this way, by reducing the braking force output by the braking system, the vehicle can use less electrical energy to keep parked, thereby achieving the effect of saving electrical energy while ensuring parking safety.

[0237] It should be noted that: the braking force output device provided in the above embodiment only uses the division of the above-mentioned functional modules as an example when controlling the braking system to output the braking force. In actual applications, the above-mentioned functions can be allocated to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above.

[0238] The functional units and modules in the above embodiments may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit, and the above integrated units may be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the protection scope of the embodiments of the present application.

[0239] The braking force output device and the braking force output method provided in the above embodiments belong to the same concept. The specific working process of the units and modules in the above embodiments and the technical effects brought about can be found in the method embodiment part and will not be repeated here.

[0240] Figure 7 It is a structural schematic diagram of a vehicle provided in an embodiment of the present application.

[0241] For example, Figure 7 As shown, the vehicle 700 includes: a memory 71 and a processor 70, wherein the memory 71 stores an executable program code 72, and the processor 70 is used to call and execute the executable program code 72 to perform the above-mentioned braking force output method.

[0242] In this embodiment, the functional modules of the vehicle can be divided according to the above method example. For example, each functional module can be corresponded, or two or more functions can be integrated into one processing module. The above integrated module can be implemented in the form of hardware. It should be noted that the division of modules in this embodiment is schematic and is only a logical function division. There may be other division methods in actual implementation.

[0243] In the case of dividing each functional module into corresponding functional modules, the vehicle may include: a first determination module, a second determination module and a braking force reduction module. It should be noted that all relevant contents of each step involved in the above method embodiment can be referred to the functional description of the corresponding functional module, which will not be repeated here.

[0244] The vehicle provided in this embodiment is used to execute the above-mentioned method of outputting braking force, and thus can achieve the same effect as the above-mentioned implementation method.

[0245] In the case of an integrated unit, the vehicle may include a processing module and a storage module. The processing module may be used to control and manage the actions of the vehicle. The storage module may be used to support the vehicle in executing corresponding program codes and data.

[0246] The processing module may be a processor or a controller, which may implement or execute various exemplary logic blocks, modules and circuits shown in conjunction with the disclosure of the present application. The processor may also be a combination that implements computing functions, such as a combination of one or more microprocessors, a combination of digital signal processing (DSP) and a microprocessor, etc. The storage module may be a memory.

[0247] This embodiment also provides a computer-readable storage medium, in which a computer program code is stored. When the computer program code is run on a computer, the computer executes the above-mentioned related method steps to implement the above-mentioned method of outputting braking force in the above-mentioned embodiment.

[0248] This embodiment also provides a computer program product. When the computer program product is run on a computer, the computer is caused to execute the above-mentioned related steps to implement the above-mentioned method of outputting braking force in the above-mentioned embodiment.

[0249] Among them, the vehicle, computer-readable storage medium, computer program product or chip provided in this embodiment are all used to execute the method provided above. Therefore, the beneficial effects that can be achieved can refer to the beneficial effects in the method provided above and will not be repeated here.

[0250] Through the description of the above implementation methods, technical personnel in the relevant field can understand that for the convenience and brevity of description, only the division of the above-mentioned functional modules is used as an example. In actual applications, the above-mentioned functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above.

[0251] In the embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are schematic, for example, the division of modules or units is only a logical function division, and there may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another device, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0252] The above contents are only specific implementation methods of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A braking force output method, characterized in that: The method comprises: When the first vehicle is braked and the brake pedal of the first vehicle is released, the brake system of the first vehicle is controlled to output a reference braking force and a first braking force of the first vehicle is determined based on the vehicle mass of the first vehicle, the target torque and the slope of the position of the first vehicle, wherein the reference braking force is the maximum braking force output by the brake system during the braking of the first vehicle, the target torque is the torque output when the first vehicle is in an idle state, and the first braking force is the theoretical braking force required for the first vehicle to be parked at the position; determining a braking force safety factor of the first vehicle based on environmental information of the location of the first vehicle, wherein the braking force safety factor is used to improve parking safety of the first vehicle; Based on the reference braking force, the first braking force, the slope, and the braking force safety factor, the braking force output by the braking system is reduced while keeping the first vehicle stationary.

2. The method according to claim 1, characterized in that The determining the first braking force of the first vehicle based on the vehicle mass of the first vehicle, the target torque, and the slope of the position of the first vehicle includes: Determine the sliding force of the first vehicle at the location based on the vehicle mass of the first vehicle and the slope; determine the target driving force based on the target torque, the transmission ratio of the first vehicle and the wheel radius; when the first vehicle is in an uphill state, determine the absolute value of the difference between the sliding force and the target driving force as the first braking force; when the first vehicle is in a downhill state, determine the absolute value of the sum of the sliding force and the target driving force as the first braking force; Alternatively, based on the vehicle mass of the first vehicle and the slope, the sliding force of the first vehicle at the current position is determined; based on the target torque, the transmission ratio of the first vehicle and the wheel radius, the target driving force is determined; when the first vehicle is in an uphill state, the absolute value of the difference between the sliding force and the target driving force is determined to obtain a first value, and the product of the first value and a parking coefficient is determined as the first braking force; when the first vehicle is in a downhill state, the absolute value of the sum of the sliding force and the target driving force is determined to obtain a second value, and the product of the second value and the parking coefficient is determined as the first braking force, and the parking coefficient is determined based on the load and / or wind resistance in the first vehicle.

3. The method according to claim 1, characterized in that The environmental information includes a slope of the first vehicle, a relative distance between the first vehicle and a second vehicle, and an estimated collision time. The determining of the braking force safety factor of the first vehicle based on the environmental information of the first vehicle includes: When the slope is less than a first slope threshold and / or the expected collision time is greater than a first time threshold, a braking force safety factor of the first vehicle is obtained from a target correspondence relationship based on the slope, the relative distance and the expected collision time.

4. The method according to claim 3, characterized in that The method further comprises: When the slope is greater than or equal to the first slope threshold and / or the estimated collision time is less than or equal to the first time threshold, the braking system is controlled to output the first braking force.

5. The method according to claim 1, characterized in that The reducing the braking force output by the braking system based on the reference braking force, the first braking force, the slope, and the braking force safety factor while keeping the first vehicle stationary includes: Based on the reference braking force, the first braking force and the slope, a multi-wheel braking force is reduced to obtain a second braking force, wherein the second braking force is a braking force that causes the wheel speed sensor of the first vehicle to start collecting a pulse signal during the braking force reduction process, and the pulse signal is an electrical signal generated when a gear rotor fixed on a wheel of the first vehicle rotates; The braking system is controlled to output a braking force based on the second braking force, the reference braking force, and the braking force safety factor.

6. The method according to claim 5, characterized in that The reducing the multi-wheel braking force based on the reference braking force, the first braking force and the slope to obtain the second braking force comprises: For the first wheel braking force reduction in the multi-wheel braking force reduction, the reference braking force is subtracted from the preset braking force to obtain the braking force after the first wheel braking force is reduced; For the i-th wheel braking force reduction in the multi-wheel braking force reduction, when the slope is less than the second slope threshold, the braking force after the i-1-th wheel braking force reduction is subtracted from the preset braking force to obtain the braking force after the i-th wheel braking force reduction, until the wheel speed sensor of the first vehicle starts to collect pulse signals; the braking force at which the wheel speed sensor starts to collect pulse signals is determined as the second braking force, where i is an integer greater than or equal to 2; When the slope is greater than or equal to the second slope threshold and less than the first slope threshold, the braking force after the i-1th wheel is reduced is subtracted from the preset braking force to obtain the braking force after the i-th wheel is reduced; after the braking force of multiple wheels is reduced to the first braking force, if the wheel speed sensor does not collect a pulse signal, the first braking force is determined to be the second braking force, and the second slope threshold is less than the first slope threshold.

7. The method according to claim 5, characterized in that The step of controlling the braking system to output the braking force based on the second braking force, the reference braking force, and the braking force safety factor includes: Multiplying the second braking force by the braking force safety factor to obtain a target braking force; The brake system is controlled to output a smaller braking force between the target braking force and the reference braking force.

8. A braking force output device, characterized in that: The device comprises: a first determination module, configured to control the braking system of the first vehicle to output a reference braking force and determine a first braking force of the first vehicle based on the vehicle mass of the first vehicle, a target torque, and a slope of a position of the first vehicle when the first vehicle is braked and the brake pedal of the first vehicle is released, wherein the reference braking force is a maximum braking force output by the braking system during the braking of the first vehicle, the target torque is a torque output when the first vehicle is in an idle state, and the first braking force is a theoretical braking force required for the first vehicle to be parked at the position; a second determining module, configured to determine a braking force safety factor of the first vehicle based on environmental information of a location of the first vehicle, wherein the braking force safety factor is used to improve parking safety of the first vehicle; A braking force reduction module is used to reduce the braking force output by the braking system based on the reference braking force, the first braking force, the slope and the braking force safety factor while keeping the first vehicle stationary.

9. A vehicle, characterized in that: The vehicle comprises: A memory for storing executable program codes; A processor, configured to call and run the executable program code from the memory so that the vehicle executes the method according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the method according to any one of claims 1 to 7 is implemented.

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