Method and device for braking vehicle by redundant braking system

Abstract

The invention provides a method for braking a vehicle through a redundant braking system, and the method comprises the steps: responding to a received signal indicating that a main braking system of the vehicle breaks down, and obtaining the rotating speed of a motor of the vehicle; first wheel speed data is obtained, and the first wheel speed data indicates the rotating speed of a first wheel driven by the motor; generating second wheel speed data using a differential model based on the motor speed and the first wheel speed data, where the second wheel speed data indicates a speed of a second wheel driven by the motor; and generating a braking command based on the first wheel speed data and the second wheel speed data.

Description

Technical Field

[0001] The present disclosure relates generally to the field of vehicles, and more particularly to a method and apparatus for braking a vehicle via a redundant braking system. Background Art

[0002] At present, more and more vehicles on the market (especially electric vehicles or hybrid vehicles) use a braking scheme that uses a main braking system in conjunction with a redundant braking system, so that in the event of a failure in the main braking system, the redundant braking system can still be used to provide the required braking capacity, thereby ensuring safe driving and improving the driving and riding experience. The role of the redundant braking system is particularly critical in autonomous driving vehicles. According to the automotive autonomous driving classification standard, when an autonomous driving vehicle is driving at level L3 and above, it cannot be expected to rely on the driver's operation to achieve control of the vehicle. On the contrary, the vehicle control system is responsible for the safe driving of the vehicle. In such a scenario, the introduction of a redundant braking system prevents the loss of control of the vehicle's braking capacity due to a failure in the main braking system. For the braking system (including the main braking system and the redundant braking system), the wheel speed is a key parameter that is essential to achieve braking control. The wheel speed is usually provided by a wheel speed sensor (WSS) attached to the wheel.

[0003] In order to provide the redundant braking system with the wheel speed data necessary for achieving accurate braking control, a redundant wheel speed sensor dedicated to providing wheel speed data to the redundant braking system may be additionally installed, or the original single-chip wheel speed sensor may be replaced with a dual-chip wheel speed sensor to independently provide wheel speed data to the main braking system and the redundant braking system, respectively. However, the above two solutions significantly increase the hardware cost, which is obviously undesirable in practical applications. Summary of the invention

[0004] In view of the above problems, it is desirable to provide an improved method, so that in the case of a failure of the main brake system, the redundant brake system can generate wheel speed data of the other side wheel driven by the motor based on the motor speed of the motor and the wheel speed data of the one side wheel driven by the motor provided by the wheel speed sensor, and generate a braking command based on the wheel speed data. In this way, at least the redundant wheel speed sensor that should be attached to the other side wheel can be saved, or the wheel speed sensor at the other side wheel does not need to be replaced with an expensive dual-chip wheel speed sensor, thereby achieving significant cost savings.

[0005] According to one aspect of the present disclosure, a method for braking a vehicle via a redundant braking system is provided, comprising: obtaining a motor speed of a motor of the vehicle in response to receiving a signal indicating a failure in a main braking system of the vehicle; obtaining first wheel speed data, wherein the first wheel speed data indicates a speed of a first wheel driven by the motor; generating second wheel speed data based on the motor speed and the first wheel speed data using a differential model, wherein the second wheel speed data indicates a speed of a second wheel driven by the motor; and generating a braking command based on the first wheel speed data and the second wheel speed data.

[0006] According to another aspect of the present disclosure, there is provided an apparatus for braking a vehicle by a redundant braking system, comprising: a memory; and a control unit. The control unit is coupled to the memory and configured to execute a method according to any one of the various embodiments of the present disclosure.

[0007] According to yet another aspect of the present disclosure, a computer-readable medium is provided, which stores a computer program including instructions, which, when executed by a control unit, configure the control unit to perform a method according to any one of the various embodiments of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Various embodiments of the claimed subject matter will now be described by way of example with reference to the accompanying drawings. In the different drawings, the same reference numerals are used to denote the same or similar components.

[0009] Figure 1A-1B A schematic diagram showing the principles of two solutions for providing wheel speed data to a redundant braking system according to an embodiment of the present disclosure.

[0010] Figure 2 A schematic diagram showing an example working principle of a primary braking system or a redundant braking system according to an embodiment of the present disclosure is shown.

[0011] Figure 3 A schematic diagram showing an example configuration of a brake system and a wheel speed sensor according to an embodiment of the present disclosure is shown.

[0012] Figure 4 A schematic diagram showing the composition of an exemplary overall braking system and the interactions between the various subsystems / components therein according to an embodiment of the present disclosure.

[0013] Figure 5 A schematic diagram showing the structure of a differential according to an embodiment of the present disclosure.

[0014] Figure 6A flow chart of a method for braking a vehicle by a redundant braking system according to an embodiment of the present disclosure is shown.

[0015] Figure 7 A block diagram of a device that can be used to implement a method for braking a vehicle by using a redundant braking system according to an embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0016] In the following description, many specific details are set forth to provide a thorough understanding of the embodiments of the present disclosure. However, those skilled in the relevant art will recognize that the present disclosure can be practiced without one or more of the specific details, or alternative methods, components, etc. can be used to practice the present disclosure. In some instances, well-known structures and operations are not shown or described in detail to avoid unnecessarily obscuring the present disclosure.

[0017] As discussed in the background technology section above, a braking scheme has been proposed that uses a main braking system in conjunction with a redundant braking system in a vehicle, so that in the event of a failure in the main braking system, the redundant braking system can still be used to provide braking capabilities that meet safety, stability and other requirements. For example, imagine such an example failure scenario, the power supply system cannot normally power the main braking system and / or the wheel speed sensor that provides wheel speed data to it, resulting in the main braking system being unable to achieve accurate and stable braking control. When the vehicle is an autonomous driving vehicle traveling at level L3 or above, the failure of the main braking system may cause serious safety problems. In this example case, the intervention of the redundant braking system is crucial to ensure the safe and stable driving of the vehicle.

[0018] Similar to the working principle of the main braking system, the redundant braking system also requires wheel speed data to achieve accurate and stable braking control. At present, wheel speed sensors attached to each wheel of the vehicle are usually used to provide such wheel speed data. In the case of introducing a redundant braking system, how to provide wheel speed data to the redundant braking system has become an issue that needs attention.

[0019] Figure 1A-1B A schematic diagram showing the principles of two solutions for providing wheel speed data to a redundant braking system according to an embodiment of the present disclosure.

[0020] like Figure 1A As shown, in a first solution, the main braking system 102 can be coupled with four existing wheel speed sensors (WSS) 104 to obtain wheel speed data of four wheels. The main braking system 102 can generate a braking command 106 based at least on the wheel speed data provided by the existing wheel speed sensors 104 to achieve braking of the vehicle. In addition, Figure 1AIt is also shown that four redundant wheel speed sensors 110 can be added and independently coupled to the redundant braking system 108 to provide redundant wheel speed data to the redundant braking system 108. In this way, in the event that the main braking system 102 or the wheel speed sensor 104 coupled to the main braking system 102 fails, the redundant braking system 108 can generate a braking command 112 based at least on the redundant wheel speed data provided by the redundant wheel speed sensor 110 to achieve braking control of the vehicle in the event that the main braking system fails.

[0021] Figure 1B A second approach to providing wheel speed data to a redundant braking system is shown. Figure 1B As shown, the original single-chip wheel speed sensor can be replaced with a dual-chip wheel speed sensor 104'. The dual-chip wheel speed sensor 104' can have two independent channels, so that its components / functions such as the input interface, processing unit, and output interface can be independently implemented without being affected by each other. As a result, the dual-chip wheel speed sensor 104' can be coupled to the main braking system 102' and the redundant braking system 108' through two independent channels at the same time to provide wheel speed data to the main braking system 102' and the redundant braking system 108', respectively. In this way, in the event that the main braking system 102' fails and cannot generate a braking command 106', the redundant braking system 108' can generate a braking command 112' using the wheel speed data provided by another channel of the dual-chip wheel speed sensor 104', thereby achieving braking control of the vehicle.

[0022] However, if Figure 1A-1B The above two solutions shown significantly increase the hardware cost, for example, the first solution involves adding a set of redundant wheel speed sensors, while the second solution involves replacing the ordinary single-chip wheel speed sensor with an expensive dual-chip wheel speed sensor. The significant cost increase caused by these two solutions is obviously undesirable.

[0023] To this end, the present disclosure provides an improved method, so that in the event of a failure of the main braking system, the redundant braking system can generate wheel speed data of the other side wheel driven by the motor based on the motor speed of the motor and the wheel speed data of the one side wheel driven by the motor provided by the wheel speed sensor, and generate a braking command based on the wheel speed data. In this way, at least the redundant wheel speed sensor that should have been attached to the other side wheel can be saved, or there is no need to replace the wheel speed sensor at the other side wheel with an expensive dual-chip wheel speed sensor, thereby achieving significant cost savings. .

[0024] First combine Figure 2To illustrate the example working principle of the braking system (including the main braking system or the redundant braking system). For ease of understanding, examples of the main braking system may include, but are not limited to, electronic body stability systems (ESP, ESC, VSC, VSM), intelligent integrated braking systems (IPB), vehicle dynamic control systems (VDC), dynamic stability control systems (DSC), dynamic stability tracking control systems (DSTC), active stability control systems (ASC), and the like as known to those skilled in the art. Examples of redundant braking systems may include, but are not limited to, electronic brake boosters, intelligent decoupling control systems (DPB), redundant braking units (RBU), and the like. In addition, the concepts of the main braking system and the redundant braking system can be used interchangeably. The two cooperate with each other in function, so that in the event of a failure of any braking system, the other braking system can respond quickly to provide accurate and stable braking control, thereby ensuring safe driving, for example, allowing the vehicle to park safely and smoothly by the side of the road.

[0025] like Figure 2 As shown, the braking system 202 may include an electronic control unit (ECU) 204 and a hydraulic adjustment unit 206. A wheel speed sensor 208 attached to each wheel may provide wheel speed data to the ECU 204 of the braking system 202. The ECU 204 may generate a braking command based at least on the wheel speed data, and transmit the braking command to the hydraulic adjustment unit 206. The hydraulic adjustment unit 206 is used to distribute the size of the brake hydraulic pressure to be applied to each wheel via the corresponding hydraulic pipeline (e.g., hydraulic pipeline 212) based on the braking command, and to deliver the corresponding amount of brake fluid in the hydraulic master cylinder to the corresponding hydraulic pipeline (e.g., hydraulic pipeline 212) through a hydraulic pump. Each hydraulic pipeline (e.g., hydraulic pipeline 212) may contain a plurality of solenoid valves (e.g., solenoid valve 214), and each solenoid valve may be a boost valve or a pressure limiting valve. By controlling the opening and closing of each solenoid valve in the corresponding hydraulic pipeline, or adjusting the size of the opening of each solenoid valve, the size of the brake hydraulic pressure acting on each wheel can be controlled and adjusted. The brake actuator (e.g., brake actuator 210) located at each wheel can brake the wheel under the action of brake hydraulic pressure. The brake actuator can be a brake caliper installed at the brake disc, which can clamp toward the wheel and achieve vehicle deceleration / braking through the friction between the brake pad and the brake disc.

[0026] It should be noted that in order to make the drawings clear, Figure 2 In the figure, only the associated wheel speed sensor 208, brake actuator 210, hydraulic line 212 and solenoid valve 214 are marked with reference numerals for one wheel. However, it should be understood that such reference numerals are also applicable to the other wheels.

[0027] At least based on the above description, it can be clearly understood that wheel speed data is crucial for the primary braking system and the redundant braking system to achieve the braking control function.

[0028] Figure 3 A schematic diagram showing an example configuration of a brake system and a wheel speed sensor according to an embodiment of the present disclosure is shown.

[0029] In such Figure 3 In the example configuration shown, the vehicle includes two motors, namely, a motor 302-1 located at the front of the vehicle and a motor 302-2 located at the rear of the vehicle, to provide driving force for the two front wheels and the two rear wheels, respectively. The vehicle also includes a main braking system 304, and four wheel speed sensors 308-1, 308-2, 308-3, 308-4 are respectively attached to the four wheels to provide wheel speed data to the main braking system 304. Imagine the example failure scenario discussed above, that is, the power supply system that supplies power to the main braking system 304 and the four wheel speed sensors 308-1, 308-2, 308-3, 308-4 fails, resulting in the main braking system 304 being unable to perform the braking control function normally. In this case, the intervention of the redundant braking system 306 is required. Figure 3 In the example configuration shown, two of the four wheel speed sensors, i.e., the wheel speed sensors 308-1 and 308-4 at the left front wheel and the right rear wheel, can be replaced from ordinary single-chip wheel speed sensors to dual-chip wheel speed sensors, so that the wheel speed sensors 308-1 and 308-4 can provide the wheel speed data for the left front wheel and the wheel speed data for the right rear wheel to the main braking system 304 and the redundant braking system 306 through independent channels, respectively. In one example, the dual-chip wheel speed sensor can include two sets of independently working functional components, including input interfaces, processing units, output interfaces, etc., and can be connected to independent power supply lines. Therefore, in the example fault scenario of power supply interruption discussed above, the wheel speed sensors 308-1 and 308-4 can still provide the wheel speed data for the left front wheel and the wheel speed data for the right rear wheel to the redundant braking system 306 through independent channels.

[0030] According to the method disclosed herein, the redundant braking system 306 can generate wheel speed data for the right front wheel using a differential model based on the motor speed of the motor 302-1 and the wheel speed data for the left front wheel provided by the wheel speed sensor 308-1. Similarly, according to the method disclosed herein, the redundant braking system 306 can generate wheel speed data for the left rear wheel using a differential model based on the motor speed of the motor 302-2 and the wheel speed data for the right rear wheel provided by the wheel speed sensor 308-4. Further, the redundant sensor 306 can generate a braking command based on the obtained wheel speed data to achieve accurate and stable braking control.

[0031] Therefore, in Figure 3 In the example configuration shown, only two of the four wheel speed sensors 308 - 1 and 308 - 4 need to be replaced with expensive dual-chip wheel speed sensors, thereby achieving significant cost savings.

[0032] Furthermore, it is understandable that although Figure 3 As shown in reference Figure 1B The example solution discussed above is to replace the single-chip wheel speed sensor with a dual-chip wheel speed sensor to provide wheel speed data to the redundant braking system through independent channels, but it is also possible to adopt the example of reference Figure 1A The scheme of adding redundant wheel speed sensors discussed. For example, a redundant wheel speed sensor attached to the left front wheel and a wheel speed sensor attached to the right rear wheel can be added accordingly. By using the method of the present disclosure, it is not necessary to add a redundant wheel speed sensor attached to the right front wheel and a redundant wheel speed sensor attached to the left rear wheel. Specifically, according to the method of the present disclosure, the redundant braking system 306 can generate wheel speed data for the right front wheel based on the motor speed of the motor 302-1 and the wheel speed data for the left front wheel provided by the redundant wheel speed sensor attached to the left front wheel, using a differential model. Similarly, the redundant braking system 306 can obtain wheel speed data for the left rear wheel based on the motor speed of the motor 302-2 and the wheel speed data for the right rear wheel provided by the redundant wheel speed sensor attached to the right rear wheel. Thus, at least the cost associated with adding a redundant wheel speed sensor attached to the right front wheel and a redundant wheel speed sensor attached to the left rear wheel can be saved.

[0033] In addition, although Figure 3 An example configuration is shown in which two motors drive the front and rear wheels respectively, but other configurations are possible. For example, the vehicle may include only one motor, and the redundant braking system may generate wheel speed data for the other side wheel driven by the motor based on the motor speed of the motor and the wheel speed data provided by the wheel speed sensor attached to the wheel on the side driven by the motor, using a differential model. Thus, only one redundant wheel speed sensor may be added or only one single-chip wheel speed sensor may be replaced with an expensive dual-chip wheel speed sensor.

[0034] Figure 4 A schematic diagram showing the composition of an exemplary overall braking system and the interactions between the various subsystems / components therein according to an embodiment of the present disclosure.

[0035] like Figure 4 As shown, the overall braking system of the vehicle includes a primary braking system 402 , a redundant braking system 404 , and a vehicle control unit (VCU) 406 , which are all coupled to a CAN bus unit 408 and implement bidirectional communication with the CAN bus unit 408 . Figure 4Also shown are wheel speed sensors 410-1, 410-2, 410-3, and 410-4. Figure 3 In the example configuration discussed, the vehicle may include two motors that drive the front and rear wheels, respectively. In such an example, wheel speed sensor 410-1 may provide wheel speed data for the left front wheel, wheel speed sensor 410-2 may provide wheel speed data for the right front wheel, wheel speed sensor 410-3 may provide wheel speed data for the left rear wheel, and wheel speed sensor 410-4 may provide wheel speed data for the right rear wheel. The wheel speed sensors 410-1 and 410-4 may adopt a dual-chip configuration to provide wheel speed data for the left front wheel and the right rear wheel to the main braking system 402 and the redundant braking system 404 through independent channels, respectively. The wheel speed sensors 410-2 and 410-3 may adopt a single-chip configuration and only provide wheel speed data for the right front wheel and the left rear wheel to the main braking system 402. It should be noted that in order to make the accompanying drawings clear, Figure 4 Only some subsystems / components and example structures of the overall braking system of the vehicle are shown. Those skilled in the art should understand that the overall braking system of the vehicle also includes other subsystems / components not shown or structures different from the structures shown. Among them, for the main braking system 402 and the redundant braking system 404, only the subcomponents ECU 412 and ECU 414 are shown, and other subcomponents and structures (for example, refer to Figure 2 The hydraulic adjustment unit, hydraulic lines, etc. discussed above are not shown in the figure for the sake of clarity. Figure 4 Shown in.

[0036] In the example fault scenario discussed above, the ECU 412 of the main brake system 402 is unable to generate a brake command based on the wheel speed data provided by the wheel speed sensors 410-1, 410-2, 410-3, and 410-4, as shown by the dotted line. In this case, the ECU 414 of the redundant brake system 404 can execute the method of the present disclosure to achieve accurate and stable brake control. Specifically, in the case where the above example fault scenario or any other possible fault occurs and causes the main brake system 402 to fail to normally implement the brake control function, the ECU 412 of the main brake system 402 can send a signal indicating that a fault has occurred to the VCU 406 (or the VCU 406). The ECU 414 of the redundant brake system 404 can receive a signal indicating that the main brake system 412 has failed via the CAN bus unit. In response to receiving such a signal, the ECU 414 of the redundant brake system 404 can execute the method of the present disclosure.

[0037] Specifically, the ECU 414 of the redundant braking system 404 can obtain the motor speed of the front motor for driving the two front wheels. In one example, the motor speed can be obtained by the VCU 406 and transmitted to the ECU 414 of the redundant braking system 404 via the CAN bus unit 408. The ECU 414 of the redundant braking system 404 can also obtain the wheel speed data for the left front wheel provided by the wheel speed sensor 410-1. Next, the ECU 414 of the redundant braking system 404 can generate the wheel speed data for the right front wheel based on the motor speed of the front motor and the wheel speed data for the left front wheel using a differential model. Similarly, the ECU 414 of the redundant braking system 404 can obtain the wheel speed data for the left rear wheel. Thus, the ECU 414 of the redundant braking system 404 can generate a braking command based on the wheel speed data of the four wheels obtained to perform accurate and stable braking control.

[0038] In the above description, it is discussed that a differential model is used to obtain the wheel speed data of the other side wheel driven by the motor based on the motor speed and the wheel speed data of the wheel on the other side driven by the motor. The differential model is proposed based on such a concept. When the vehicle is traveling in a straight line, the rotation speeds of the left and right wheels driven by the same motor are equal. When the vehicle turns, the travel distance of the wheel on the outside of the turning path is longer than the travel distance of the wheel on the inside of the turning path. Therefore, in order to avoid wheel slippage, the rotation speed of the outer wheel should be greater than the rotation speed of the inner wheel. At the same time, there is a linear relationship between the motor speed of the motor driving the two wheels and the rotation speed of the outer wheel and the rotation speed of the inner wheel. Therefore, using such a linear relationship, when the motor speed and the rotation speed of the wheel on one side driven by the motor are known, the rotation speed of the wheel on the other side driven by the motor can be calculated. The differential model describing this linear relationship can be stored in the memory of the ECU 414 of the redundant braking system 404 in the form of software as an algorithm, program, function, etc., and executed by its control unit, as shown below in combination Figure 7 discussed.

[0039] The above differential control for wheel steering scenarios can be achieved through a differential in the vehicle structure, and the above differential model is proposed based on the physical characteristics of the differential. Figure 5 Further detailed discussion. Figure 5 A schematic diagram showing the structure of a differential according to an embodiment of the present disclosure.

[0040] exist Figure 5, a transmission shaft 502 driven by a motor, a first half shaft 506-1 driving a first wheel driven by the motor to rotate, and a second half shaft 506-2 driving a second wheel driven by the motor to rotate are shown. The differential can be coupled between the transmission shaft 502, the first half shaft 506-1 and the second half shaft 506-2. Driven by the motor, the transmission shaft 502 rotates, and the main gear 508 is driven to rotate through the meshing structure between the gear 504 and the main gear 508 of the differential. It should be understood that the rotation speed of the transmission shaft 502 is equal to the motor speed of the motor. The rotation speed of the main gear 508 is proportional to the rotation speed of the transmission shaft 502, and the proportional relationship between the two depends on the tooth ratio between the gear 504 and the main gear 508. The main gear 508 is connected to the planetary gear 510 through a fixed connection structure (although Figure 5 Another planetary gear opposite to the planetary gear 510 is also shown in the example differential structure, but depending on different configurations, the differential may include one or more planetary gears, and the number of planetary gears does not limit the scope of protection of the present disclosure). Due to the fixed connection with the main gear 508, the planetary gear 510 can rotate along the direction 514 as the main gear 508 rotates, also known as revolution. At the same time, when the vehicle turns, the planetary gear 510 can also rotate along the direction 516, and drive the first half-shaft gear 512-1 and the second half-shaft gear 512-2 to rotate through the meshing structure. Since the planetary gear 510 revolves and rotates at the same time, the first half-shaft gear 512-1 and the second half-shaft gear 512-2 can rotate at different speeds, so that the first half-shaft 506-1 and the second half-shaft 506-2 respectively connected thereto drive the first wheel and the second wheel to rotate at different speeds. Meanwhile, based on such an exemplary differential structure, the rotation speed N0 of the main gear 508, the rotation speed N1 of the first side gear 512-1, and the rotation speed N2 of the second side gear 512-2 have the following linear relationship:

[0041] N1+N2=2*N0

[0042] Thus, according to the method disclosed herein, when the braking control function cannot be realized by the main braking system, the ECU of the redundant braking system can perform the following operations. First, the motor speed is obtained. Based on the motor speed, according to the gear ratio between the gear 504 and the main gear 508 discussed above, the speed N0 of the main gear 508 can be calculated.

[0043] Next, the first wheel speed data for the first wheel provided by the wheel speed sensor can be obtained. The first wheel speed data can be provided by a redundant single-chip wheel speed sensor attached to the first wheel. Alternatively, the first wheel speed data can be provided by a dual-chip wheel speed sensor with an independent channel for a redundant braking system. In one example, the wheel speed data provided by the wheel speed sensor can include a square wave signal in which a high level and a low level alternately appear. The ECU of the redundant braking system can process the square wave signal to obtain the rotation speed of the wheel. Depending on different wheel speed sensor types, such as an inductive wheel speed sensor, a Hall wheel speed sensor, a magnetoresistive wheel speed sensor, and the like, the wheel speed data provided by the wheel speed sensor can include sensor signals in other forms other than square waves, such as sine waves, or other pulse signals. Thus, based on the first wheel speed data, the rotation speed of the first wheel can be calculated, and the calculated rotation speed of the first wheel can be equal to the rotation speed N1 of the first half-shaft gear 512-1. Then, according to the above linear relationship, based on the rotation speed N0 of the main gear 508 and the rotation speed N1 of the first side gear 512-1, the rotation speed N2 of the second side gear 512-2 can be calculated. The rotation speed N2 can be equal to the rotation speed of the second wheel. It should be understood that the unit of the rotation speed discussed above can be r / s (revolutions per second), and the wheel speed of the wheel (whose unit can be m / s (meters per second)) can be further calculated based on the radius / circumference data of the wheel.

[0044] Finally, the ECU of the redundant braking system can generate braking commands based on the obtained wheel speed data to achieve accurate and stable braking control functions.

[0045] The following will be combined Figure 6 A flow chart describing a method of braking a vehicle via a redundant braking system according to one embodiment of the present disclosure. Figure 6 The method sequence shown can be executed by an ECU of a redundant brake system.

[0046] In step S610, in response to receiving a signal indicating that a main brake system of the vehicle has failed, a motor speed of a motor of the vehicle may be obtained. As discussed above, the motor speed may be provided by a VCU of the vehicle.

[0047] In step S620, first wheel speed data may be obtained, wherein the first wheel speed data indicates a rotational speed of a first wheel driven by the motor. In one example, the first wheel speed data may be provided by a redundant single-chip wheel speed sensor attached to the first wheel. Alternatively, the first wheel speed data may be provided by a dual-chip wheel speed sensor having independent channels for a redundant braking system.

[0048] In step S630, the second wheel speed data can be generated by using a differential model based on the motor speed and the first wheel speed data, wherein the second wheel speed data indicates the speed of the second wheel driven by the motor. The differential model can characterize the linear relationship between the motor speed, the speed of the first wheel, and the speed of the second wheel. In one example, the differential model can be based on the physical characteristics of the vehicle's differential. The differential can be coupled between a drive shaft driven by the motor and a first half-shaft that drives the first wheel to rotate and a second half-shaft that drives the second wheel to rotate, and includes a main gear that rotates under the drive shaft, a first half-shaft gear that drives the first half-shaft to rotate, and a second half-shaft gear that drives the second half-shaft to rotate. Based on the physical characteristics of the differential, the following linear relationship can be derived: N1+N2=2*N0, wherein N0 represents the speed of the main gear, N1 represents the speed of the first half-shaft gear, and N2 represents the speed of the second half-shaft gear.

[0049] In step S640, a braking command may be generated based on the first wheel speed data and the second wheel speed data. The braking command may be output to, for example, the above reference Figure 2 The hydraulic adjustment unit discussed is used to control and adjust the braking force acting on each wheel.

[0050] Figure 7 A block diagram of a device 700 that can be used to implement a method for braking a vehicle using a redundant braking system according to an embodiment of the present disclosure is shown. In one example, the device 700 may include an electronic control unit of a vehicle, such as the one described above with reference to Figure 4 ECU 414 of redundant braking system 404 is discussed, among others.

[0051] The example device 700 includes a control unit 704 connected to an internal communication bus 702, and the control unit 704 is used to execute instructions in a memory 706 to implement the method of braking a vehicle by a redundant braking system described in detail above. Examples of the control unit 704 may include a central processing unit (CPU), a microcontroller, and the like. The memory 706 suitable for tangibly embodying computer program instructions and data includes various forms of memory, such as EPROM, EEPROM, and flash memory devices, and the like. The device 700 may also include an input interface 708 and an output interface 710. The input interface 708 is used to receive input signals and data, including, for example, a fault signal indicating that a fault has occurred in the main braking system, and sensor data from a wheel speed sensor, and the like. The output interface 710 is used to send output signals and data, such as a braking command generated based on the wheel speed data.

[0052] The computer program may include instructions executable by a computer, which are used to cause the control unit 704 of the device 700 to perform the method of braking a vehicle by a redundant braking system disclosed herein. The program may be recorded on any data storage medium including a memory. For example, the program may be implemented in digital electronic circuits, or in computer hardware, firmware, software, or a combination thereof. The process / method steps described in the present disclosure may be performed by a programmable processor that executes program instructions to perform methods, steps, operations by operating on input data and generating outputs.

[0053] In addition to what is described herein, various modifications may be made to the disclosed embodiments and implementations of the present invention without departing from the scope of the disclosed embodiments and implementations of the present invention. Therefore, the descriptions and examples herein should be interpreted as illustrative rather than limiting. The scope of the present invention should be measured only by reference to the claims.

Claims

1. A method for braking a vehicle by means of a redundant braking system, comprising: In response to receiving a signal indicating a failure of a main brake system of the vehicle, obtaining a motor speed of a motor of the vehicle; obtaining first wheel speed data, wherein the first wheel speed data indicates a rotation speed of a first wheel driven by the motor; generating second wheel speed data using a differential model based on the motor speed and the first wheel speed data, wherein the second wheel speed data indicates a speed of a second wheel driven by the motor; and A braking command is generated based on the first wheel speed data and the second wheel speed data.

2. The method according to claim 1, wherein: The differential model represents a linear relationship between a rotation speed of the motor, a rotation speed of the first wheel, and a rotation speed of the second wheel.

3. The method according to claim 1, wherein: The differential model is based on the physical characteristics of the vehicle's differential; and The differential is coupled between a transmission shaft driven by the motor and a first half-shaft driving the first wheel to rotate and a second half-shaft driving the second wheel to rotate.

4. The method according to claim 3, wherein: The differential comprises: A main gear that rotates driven by the transmission shaft; A first half-shaft gear driving the first half-shaft to rotate; and The second half-shaft gear drives the second half-shaft to rotate.

5. The method according to claim 4, wherein: The differential model characterizes the following linear relationship: N1+N2=2*N0 Among them, N0 represents the rotation speed of the main gear, N1 represents the rotation speed of the first side gear, and N2 represents the rotation speed of the second side gear.

6. The method according to claim 5, wherein: The rotation speed N0 of the main gear is calculated based on the motor rotation speed, and wherein the motor rotation speed is proportional to the rotation speed N0 of the main gear; and The rotation speed N1 of the first side gear is calculated based on the first wheel speed data.

7. The method according to claim 1, wherein: The first wheel speed data is provided by a redundant single-chip wheel speed sensor attached to the first wheel; or The first wheel speed data is provided by a dual chip wheel speed sensor having independent channels for the redundant braking system.

8. A device for braking a vehicle by means of a redundant braking system, comprising: Memory; A control unit is coupled to the memory, wherein the control unit is configured to execute the method according to any one of claims 1-7.

9. A computer readable medium storing a computer program comprising instructions which, when executed by a control unit, cause the control unit to be configured to perform the method according to any one of claims 1 to 7.

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