Brake-by-wire system

Abstract

The invention discloses a brake-by-wire system, and belongs to the technical field of automobiles. The system comprises an electronic parking brake system (EPB), an electronic hydraulic brake system (EHB), a vehicle control unit (VCU), a motor control unit (MCU), an automatic driving assistance system (ADAS), a remote controller, a wireless communication module and a sensor module, the VCU is connected with the EPB, the EHB, the MCU, the ADAS and the sensor module, and meanwhile the VCU communicates with the remote controller through the wireless communication module; the VCU is used for judging the current operation mode of the chassis according to the working condition of the whole vehicle and sending a control command to the EPB, the EHB and the MCU in the corresponding operation mode, and the modes comprise a preparation mode, an automatic driving mode, a remote control mode and an emergency mode. Intelligent braking under various chassis operation modes is achieved, the safety of the vehicle is guaranteed, and meanwhile the endurance of the vehicle is prolonged through the recovery braking process.

Description

Technical Field

[0001] The invention belongs to the technical field of automobiles, and in particular, relates to a wire-controlled brake system. Background Art

[0002] Braking by wire is an important part of modern automotive technology. It controls the braking system through electronic signals, replacing the traditional mechanical connection method, thus achieving more efficient and safer braking control. The background and development of this technology can be traced back to the transition from hydraulic braking system to electronic stability control system, and then developed intelligent braking by wire system, the so-called One-Box and Two-Box system.

[0003] The development of brake-by-wire technology is closely related to the progress of autonomous driving technology. With the gradual implementation of high-level autonomous driving regulations, brake-by-wire technology, as the core of autonomous driving technology, has continued to expand its penetration and application scope. For example, the promotion and application of L2-L4 autonomous driving vehicles requires brake-by-wire technology to achieve longitudinal and lateral control of the vehicle, ensuring that the vehicle can plan the path through the algorithm based on the environmental information collected by the sensor, and accurately control the vehicle's driving by wire control.

[0004] In addition, the advantages of wire control brake technology lie in its high precision, fast response and support for energy recovery, which make it have significant effects in improving driving safety, enhancing driving experience and promoting energy conservation and emission reduction. With the continuous advancement of technology and the growth of market demand, wire control brake technology is gradually becoming an important development direction of the automotive industry.

[0005] Traditional braking systems cannot achieve automatic braking and accurate and rapid control of brake pressure, and cannot meet the requirements of smart cars for braking systems. Braking systems need to be electrified and intelligent.

[0006] To this end, the present invention proposes a wire control brake system. Summary of the invention

[0007] The present invention aims to overcome the deficiencies of the prior art and proposes a brake-by-wire system to achieve the following objectives: to achieve intelligent braking in a variety of chassis operating modes, to ensure vehicle safety, and to increase vehicle endurance through a recovery braking process.

[0008] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a wire control braking system, the system includes an electronic parking brake system EPB, an electronic hydraulic brake system EHB, a vehicle controller VCU, a motor controller MCU, an automatic driving assistance system ADAS, a remote control, a wireless communication module, and a sensor module, wherein the VCU is connected to the EPB, EHB, MCU, ADAS, and sensor module respectively, and at the same time, the VCU also communicates with the remote control through the wireless communication module; the VCU is used to determine the current operating mode of the chassis according to the working condition of the whole vehicle, and issue control commands to the EPB, EHB, and MCU in the corresponding operating mode, and the modes include preparation mode, automatic driving mode, remote control mode and emergency mode.

[0009] Preferably, in any chassis operation mode, after the EHB executes the control command issued by the VCU to brake the vehicle and stop it, the EHB will maintain the current brake fluid pressure for a preset period of time. During the preset time, the EPB monitors in real time whether the VCU issues a vehicle drive instruction to the MCU. If not, the EPB automatically performs the parking action.

[0010] Preferably, in any chassis operating mode other than the automatic driving mode, the EPB does not respond to the parking command issued by the VCU; only in the automatic driving mode, the EPB receives the parking command issued by the VCU, and when the parking command changes, the EPB responds immediately; when the parking command remains unchanged, the EPB automatically acts according to its own needs.

[0011] Preferably, the EHB decomposes the braking demand into a mechanical braking part and a motor regenerative braking part, wherein the motor regenerative braking part is fed back to the VCU, which is processed by the VCU and forwarded to the MCU for implementation.

[0012] Preferably, the VCU determines whether the EHB has a fault and the fault level through sensors configured on the EHB. When the fault level of the EHB is less than or equal to a preset level, the VCU sends a control command to the MCU to limit the vehicle speed; when the fault level of the EHB is greater than the preset level, the VCU sends a control command to the EHB, and the EHB brakes to stop after receiving the command.

[0013] Preferably, the EHB periodically sends a verification message to the VCU and waits for feedback from the VCU. If the VCU does not provide feedback within a preset time, the EHB actively brakes to a stop.

[0014] Preferably, in the automatic driving mode, ADAS calculates the braking requirement based on the target speed and target acceleration and sends a braking requirement signal. After receiving the braking requirement signal sent by ADAS, the VCU determines that it is currently in the automatic driving mode and forwards the braking requirement signal sent by ADAS to the EHB.

[0015] Preferably, in remote control mode, the user sends a braking demand signal through the remote control and forwards it to the VCU through the wireless communication module. After receiving the braking demand signal sent by the remote control, the VCU determines that it is currently in remote control mode and forwards the braking demand signal sent by the remote control to the EHB.

[0016] Preferably, when the VCU does not receive signals from ADAS and the remote control, if the current vehicle speed is 0 and the entire vehicle is in an initialization state, the VCU determines that it is currently in a preparation mode and sets the braking demand signal to 0; in the preparation mode, if the VCU detects that the vehicle speed is suddenly greater than 0, the VCU issues an emergency stop command to the EHB.

[0017] Preferably, when the VCU detects an abnormality of the vehicle through the sensor module, the VCU determines that it is currently in emergency mode and sets the braking demand signal to 0, and at the same time, directly sends an emergency stop command to the EHB.

[0018] The technical effect of the present invention is that the brake-by-wire system is controlled by electronic signals, and the response speed is faster, making the braking of the car faster and more efficient. This fast response characteristic is crucial to improving driving safety, especially in emergency braking, which can significantly shorten the braking distance and reduce the risk of accidents. The brake-by-wire system can reduce energy consumption by recovering the energy generated during braking, thereby improving fuel economy or increasing the range of electric vehicles. This function is of great significance to improving energy efficiency and reducing operating costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The figure is a structural diagram of a brake-by-wire system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0020] The following is a further detailed description of the specific implementation of the present invention by describing the embodiments with reference to the accompanying drawings, with the purpose of helping those skilled in the art to have a more complete, accurate and in-depth understanding of the inventive concept and technical solution of the present invention and to facilitate its implementation. In order to make the technical solution of the present invention clearer, the present invention is explained by the following embodiments.

[0021] This embodiment proposes a wire control brake system, such as Figure 1As shown, the system includes an electronic parking brake system EPB, an electronic hydraulic brake system EHB, a vehicle controller VCU, a motor controller MCU, an automatic driving assistance system ADAS, a remote controller, a wireless communication module, and a sensor module, wherein the VCU is connected to the EPB, EHB, MCU, ADAS, and sensor module respectively, and at the same time, the VCU also communicates with the remote controller through the wireless communication module.

[0022] Specifically, the sensor module of this embodiment includes the commonly used vehicle speed sensors, radars, cameras, etc. on the whole vehicle, as well as brake fluid pressure sensors, liquid level sensors, etc. configured on the EHB. The data collected by these sensors are all sent to the VCU, so that the VCU can realize rapid braking of the vehicle in different modes after processing and analyzing the data. Among them, the analysis of the data collected by the speed sensor, radar, camera, etc. can obtain the current working condition of the whole vehicle; the analysis of the data collected by the brake fluid pressure sensor, liquid level sensor, etc. configured on the EHB can obtain the working condition of the EHB, including fault conditions.

[0023] In this embodiment, the wireless communication module can be configured on the VCU, and can specifically communicate with the remote controller through wireless communication devices based on infrared, wifi, Bluetooth, etc. Further, the VCU of this embodiment is respectively connected with the EPB, EHB, MCU, ADAS, and sensor module through the CAN bus. As a commonly used communication medium in automotive technology, the CAN bus has the advantages of fast and stable transmission rate. At the same time, the CAN bus is easy to configure, which can effectively reduce costs.

[0024] In this embodiment, the VCU is used to determine the current operating mode of the chassis after analyzing the vehicle operating conditions based on sensor data, and issue control commands to the EPB, EHB, and MCU in the corresponding operating mode, which includes a preparation mode, an automatic driving mode, a remote control mode, and an emergency mode. Specifically:

[0025] In the automatic driving mode, ADAS will automatically determine whether braking is required, and when braking is required, calculate the braking demand based on the target speed and target acceleration and send a braking demand signal. After receiving the braking demand signal sent by ADAS, the VCU determines that it is currently in automatic driving mode, and forwards the braking demand signal sent by ADAS to the EHB. The EHB converts the braking demand signal into a brake fluid pressure signal and then performs braking.

[0026] In remote control mode, the user sends a braking demand signal through the remote control and forwards it to the VCU through the wireless communication module. The remote control of this embodiment is equipped with a joystick. The upward movement of the joystick indicates driving, and the downward movement indicates braking. The corresponding driving signal or braking demand signal is forwarded to the VCU through the wireless communication module. After receiving the braking demand signal sent by the remote control, the VCU determines that it is currently in remote control mode, and forwards the braking demand signal sent by the remote control to the EHB. The EHB converts the braking demand signal into a brake fluid pressure signal and then performs braking.

[0027] When the VCU does not receive signals from ADAS and the remote controller, if the current vehicle speed is 0 and the vehicle is in the initialization state, the VCU determines that it is currently in the preparation mode and sets the brake demand signal to 0. In the preparation mode, if the VCU detects that the vehicle speed is suddenly greater than 0, indicating that the vehicle starts abnormally or slips, the VCU sends an emergency stop command to the EHB, and the EHB converts the emergency stop command into a brake fluid pressure signal and executes braking to protect the safety of the vehicle.

[0028] When the VCU detects a vehicle abnormality through the sensor module, the VCU determines that it is currently in emergency mode and sets the brake demand signal to 0. At the same time, it directly sends an emergency stop command to the EHB, and the EHB converts the emergency stop command into a brake fluid pressure signal and then performs braking. Vehicle abnormalities include vehicle overspeeding, the vehicle is about to collide with an obstacle, etc. At this time, the vehicle must brake in time to ensure vehicle safety.

[0029] The brake demand signal and the brake fluid pressure signal converted from the emergency stop command represent two different levels of brake fluid pressure. Obviously, the brake fluid pressure level of the emergency stop command will be higher, thereby achieving faster braking. In the preparation mode and emergency mode, the conventional brake demand signal may not meet the braking requirements in an emergency situation, so a higher level of emergency stop command is required. At the same time, in order to avoid the interference of the brake demand signal on the emergency stop command, the embodiment sets the brake demand signal to 0 in the preparation mode and emergency mode, that is, sets it to invalid.

[0030] In this embodiment, the EHB decomposes the braking demand (i.e., the braking demand signal or the emergency stop command) into a mechanical braking part and a motor regenerative braking part, wherein the mechanical braking part is converted into a brake fluid pressure signal and executed by the EHB, and the motor regenerative braking part is fed back to the VCU, which is forwarded to the MCU for implementation after processing. The MCU switches the motor to a generator, and realizes kinetic energy recovery during deceleration braking, thereby increasing the cruising range of new energy vehicles. When the EHB performs the braking action, it needs to feed back a start braking signal to the VCU, and the system is correspondingly configured with a brake indicator light, which lights up the VCU after receiving the start braking signal.

[0031] In any chassis operation mode, after the EHB executes the control command issued by the VCU (i.e., the braking demand signal or the emergency stop command) to brake the vehicle and stop it, the EHB will maintain the current brake fluid pressure for a preset period of time (set to 2 minutes in this embodiment, and can be flexibly set according to actual conditions in specific applications). During the preset time, the EPB monitors in real time whether the VCU issues a vehicle drive command to the MCU. If so, it means that the vehicle has ended braking and resumed driving; if not, in order to ensure vehicle stability and avoid accidents such as slipping, the EPB automatically performs parking actions.

[0032] In any other chassis operation mode except the automatic driving mode, the EPB does not respond to the parking command issued by the VCU. In the preparation mode, remote control mode and emergency mode, if the EPB responds to the parking command issued by the VCU, it may cause a conflict with the original control command in the corresponding mode. Taking the preparation mode as an example, in the preparation mode, the EPB may be in the initialization or self-test process. If it responds to the parking command of the VCU at this time, the initialization or self-test process may be interrupted. In this way, even if the EPB completes the parking, due to the interruption of the initialization or self-test process, there will be safety hazards in the subsequent use of the EPB. Therefore, in this embodiment, only in the automatic driving mode, the EPB receives the parking command issued by the VCU. This is because in the automatic driving mode, the driving and parking states of the vehicle are planned and controlled autonomously by the ADAS. When the parking command changes, the EPB responds immediately, which means that the ADAS makes a decision to park or release the parking according to the vehicle working conditions. For example, when the traffic light turns red, the ADAS drives the EPB to park, and when the red light turns green, the ADAS drives the EPB to release the parking. At the same time, when the parking command remains unchanged, the EPB automatically acts according to its own needs. For example, when the ADAS always drives the vehicle in the parking state, the EPB will combine the sensor to judge the current parking environment, such as slope, temperature, etc., and adjust the tightness of the parking device to ensure vehicle safety. In summary, the EPB configured in this way in this embodiment releases the control resources of the VCU to a certain extent.

[0033] In order to ensure that the vehicle can complete braking, it is necessary to monitor the EHB in real time so as to detect and resolve faults in a timely manner. The VCU of this embodiment determines whether the EHB has a fault and the fault level through the sensor configured on the EHB, and handles it according to the fault. For example, if there is a fault in the brake fluid pressure of the EPB, the fault level is set downward in descending order according to the normal brake fluid pressure. Assuming that 10MPA is the normal brake fluid pressure, then 10MPA to 7MPA is a level 1 fault, 7MPA to 5MPA is a level 2 fault, and so on. In specific implementation, multiple types of faults can also be combined to divide the fault levels. This is a common practice for those skilled in the art and will not be elaborated in this application.

[0034] When the fault level of the EHB is less than or equal to a preset level (set to level 2 in this embodiment, which can be flexibly selected according to actual conditions during implementation), the VCU sends a control command to the MCU to limit the vehicle speed. In this embodiment, the speed limit value is 15m / h. Which can be flexibly selected according to actual conditions during implementation; when the fault level of the EHB is greater than the preset level, the VCU sends a control command to the EHB, and the EHB brakes to stop after receiving the command.

[0035] In order to ensure normal braking of the vehicle in the event of VCU failure or communication interruption between EPB and VCU, the EPB configuration of this embodiment is as follows: EPB periodically sends verification messages to the VCU and waits for VCU feedback. If the VCU does not provide feedback within a preset time (set to 10s in this embodiment), the EHB actively brakes to stop.

[0036] The present invention is described above by way of example in conjunction with the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-mentioned methods. As long as various non-substantial improvements are made using the method concept and technical solution of the present invention; or the above concept and technical solution of the present invention are directly applied to other occasions without improvement, they are all within the protection scope of the present invention.

Claims

1. A brake-by-wire system, characterized in that: The system includes an electronic parking brake system EPB, an electronic hydraulic brake system EHB, a vehicle controller VCU, a motor controller MCU, an automatic driving assistance system ADAS, a remote controller, a wireless communication module, and a sensor module, wherein the VCU is connected to the EPB, EHB, MCU, ADAS, and sensor module respectively, and at the same time, the VCU also communicates with the remote controller through the wireless communication module; the VCU is used to determine the current operating mode of the chassis according to the vehicle working condition, and issue control commands to the EPB, EHB, and MCU in the corresponding operating mode, and the modes include preparation mode, automatic driving mode, remote control mode, and emergency mode.

2. A brake-by-wire system according to claim 1, characterized in that: In any chassis operation mode, after EHB executes the control command issued by the VCU to brake and stop the vehicle, EHB will maintain the current brake fluid pressure for a preset period of time. During the preset time, EPB monitors in real time whether VCU issues a vehicle drive command to MCU. If not, EPB automatically performs parking action.

3. A brake-by-wire system according to claim 1, characterized in that: In any chassis operating mode other than the automatic driving mode, the EPB does not respond to the parking command issued by the VCU; only in the automatic driving mode, the EPB receives the parking command issued by the VCU, and responds immediately when the parking command changes; when the parking command remains unchanged, the EPB automatically acts according to its own needs.

4. The brake-by-wire system according to claim 1, characterized in that: The EHB decomposes the braking demand into a mechanical braking part and a motor regenerative braking part, wherein the motor regenerative braking part is fed back to the VCU, which is processed by the VCU and forwarded to the MCU for implementation.

5. The brake-by-wire system according to claim 1, characterized in that: The VCU determines whether the EHB has a fault and the fault level through the sensors configured on the EHB. When the fault level of the EHB is less than or equal to the preset level, the VCU sends a control command to the MCU to limit the vehicle speed; when the fault level of the EHB is greater than the preset level, the VCU sends a control command to the EHB, and the EHB brakes to stop after receiving the command.

6. The brake-by-wire system according to claim 1, characterized in that: The EHB periodically sends a verification message to the VCU and waits for feedback from the VCU. If the VCU does not provide feedback within a preset time, the EHB actively brakes to a stop.

7. The brake-by-wire system according to claim 1, characterized in that: In the automatic driving mode, ADAS calculates the braking requirement based on the target speed and target acceleration and sends a braking requirement signal. After receiving the braking requirement signal sent by ADAS, the VCU determines that it is currently in the automatic driving mode and forwards the braking requirement signal sent by ADAS to the EHB.

8. The brake-by-wire system according to claim 1, characterized in that: In remote control mode, the user sends a braking demand signal through the remote control and forwards it to the VCU through the wireless communication module. After receiving the braking demand signal sent by the remote control, the VCU determines that it is currently in remote control mode and forwards the braking demand signal sent by the remote control to the EHB.

9. A brake-by-wire system according to any one of claims 7 or 8, characterized in that: When the VCU does not receive any signal from the ADAS and remote control, if the current vehicle speed is 0 and the vehicle is in the initialization state, the VCU determines that it is currently in the preparation mode and sets the braking demand signal to 0; in the preparation mode, if the VCU detects that the vehicle speed is suddenly greater than 0, the VCU issues an emergency stop command to the EHB.

10. A brake-by-wire system according to any one of claims 7 or 8, characterized in that: When the VCU detects an abnormality in the vehicle through the sensor module, the VCU determines that it is currently in emergency mode and sets the braking demand signal to 0, and at the same time, directly sends an emergency stop command to the EHB.

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