阅读说明：本技术 一种热备用电子驻车制动系统协调控制方法 (Hot standby electronic parking brake system coordination control method ) 是由 刘长运 邱宝象 李昊阳 吴华君 屈亮亮 于 2020-12-23 设计创作，主要内容包括：本发明公开了一种热备用电子驻车制动系统协调控制方法,主要包括主芯片和从芯片。本发明实现了EPB从芯片的驻车/解驻功能,在无故障状态下,主芯片可以实现所有EPB功能,从芯片实时监测主芯片工作是否正常,当主芯片功能失效或通信异常后,从芯片接管EPB功能,主芯片恢复正常后,再次由主芯片实现EPB功能；从芯片具备EPB功能,可实现手动驻车、手动释放、熄火自动驻车、P档自动驻车、智能驻车、动态驻车、降级驻车、再夹紧功能的备份,可用于无P档锁止机构的纯电动车辆；主从芯片实现无缝切换,避免卡钳状态错误,引起的最大动作时间延长为200ms,不对驾驶员产生干扰。(The invention discloses a coordination control method of a hot standby electronic parking brake system. The invention realizes the parking/parking function of the EPB slave chip, the master chip can realize all EPB functions in a fault-free state, the slave chip monitors whether the master chip works normally or not in real time, when the master chip fails in function or is abnormal in communication, the slave chip takes over the EPB function, and after the master chip recovers to be normal, the master chip realizes the EPB function again; the slave chip has an EPB function, can realize backup of manual parking, manual release, flameout automatic parking, P-gear automatic parking, intelligent parking, dynamic parking, degraded parking and re-clamping functions, and can be used for pure electric vehicles without a P-gear locking mechanism; the master chip and the slave chip realize seamless switching, avoid the condition error of the calipers, prolong the maximum action time to 200ms and do not generate interference to drivers.)

1. A hot standby electronic parking brake system coordination control method is characterized in that: the method mainly comprises the following steps:

1) the master chip actively judges whether the drive is normal or not, whether the master chip can complete EPB action or not, and sends the data to the slave chip;

2) when the master chip and the slave chip start to execute the EPB action, judging the current state according to whether the previous action is executed by the master chip and whether the execution is normal or not, interacting with the opposite chip when the current state cannot be judged, confirming the execution condition of the opposite chip, and judging by additionally executing a state confirmation action if the current state cannot be judged;

3) the slave chip firstly judges whether the slave chip is in a forbidden state, does not take over EPB in the forbidden state and is used for updating the operation of the program of the master chip;

4) the slave chip judges whether the monitoring communication is overtime or not, whether the communication data is updated normally or not and whether the communication data is effective or not, and when any condition occurs, the slave chip prepares to take over;

5) when the master chip actively requires the slave chip to take over, the corresponding take-over mark value is sent to the slave chip, and the slave chip recognizes the take-over mark value and prepares for take over;

6) the EPB sends CAN signals to the whole vehicle, and the CAN signals are sent by a chip which currently realizes the EPB function;

7) when the master chip and the slave chip both identify the fault that the EPB function can not be normally executed during the drive diagnosis, the slave chip requests the HMI to display to prompt the driver that the EPB function is invalid.

2. The cooperative control method of the hot-standby electronic parking brake system according to claim 1, characterized in that: and (3) determining the state in the step (2) as the forward rotation of the EPB motor, judging whether the friction plate contacts the brake disc according to the fed-back motor current, then reversing the motor to a set caliper displacement, determining the state at the moment as a release state, and executing a normal clamping driving process when clamping needs to be executed.

3. The cooperative control method of the hot-standby electronic parking brake system according to claim 1, characterized in that: in the process of taking over by the master chip and the slave chip, the time from the occurrence of the event for triggering the take-over to the completion of the take-over is less than 200 ms.

4. The cooperative control method of the hot-standby electronic parking brake system according to claim 1, characterized in that: the main chip and the slave chip exchange data to realize redundant receiving and sending through serial port data and CAN data, wherein the serial port data exchange period is 10ms, and the CAN data exchange period is 20 ms.

5. The cooperative control method of the hot-standby electronic parking brake system according to claim 1, characterized in that: the master chip and the slave chip have the functions of fault state, take-over mark, clamping force, clamping displacement, communication counting and communication check data according to interactive parameters, and have the functions of drive capability diagnosis, response EPB action judgment, EPB state judgment and interactive data transceiving besides normal function logic.

Technical Field

The invention relates to the field of electronic parking brake systems, in particular to a coordination control method of a hot standby electronic parking brake system.

Background

The EPB is an electronic parking brake system. The existing EPB system acts as a single chip, a slave chip only monitors whether a master chip can cause the motor to be electrified for a long time or not, and cuts off the motor drive of the master chip when the master chip is abnormal, so that the motor, calipers or a drive circuit are prevented from being damaged due to overheating. The master chip is responsible for realizing all EPB functions, the slave chip monitors whether the communication of the master chip is normal or not in real time, whether the forward/reverse rotation time of the master chip driving motor exceeds the time required by the execution of normal static/dynamic functions or not, and when the master chip is judged to work abnormally, the slave chip cuts off an MOS (metal oxide semiconductor) tube of a motor driving loop to enable the EPB motor to stop abnormal actions. The prior art mainly has the following problems: the slave chip only has the functions of watchdog and preventing the motor from being continuously driven, and the function is single; because the slave chip can not directly drive the motor, when the master chip can not work normally, the slave chip can not realize the parking/parking function, so that the vehicle can not continue to run in the parking state; in the parking state of the vehicle, the parking on a large slope cannot be realized due to the limited locking torque of the P gear locking mechanism of the gearbox; at present, a pure electric vehicle is not provided with a gearbox generally, so that the cost for adding a P gear locking mechanism is higher, and the regulation requires that after one-way parking brake fails, the vehicle can be kept in a static state on a road with a slope less than a certain gradient, and the current EPB cannot meet the safety requirement.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provides a coordinated control method for a hot standby electronic parking brake system.

The purpose of the invention is achieved by the following technical scheme: the method for coordinately controlling the hot standby electronic parking brake system mainly comprises the following steps:

1) the master chip actively judges whether the drive is normal or not, whether the master chip can complete EPB action or not, and sends the data to the slave chip;

2) when the master chip and the slave chip start to execute the EPB action, judging the current state according to whether the previous action is executed by the master chip and whether the execution is normal or not, interacting with the opposite chip when the current state cannot be judged, confirming the execution condition of the opposite chip, and judging by additionally executing a state confirmation action if the current state cannot be judged;

3) the slave chip firstly judges whether the slave chip is in a forbidden state, does not take over EPB in the forbidden state and is used for updating the operation of the program of the master chip;

4) the slave chip judges whether the monitoring communication is overtime or not, whether the communication data is updated normally or not and whether the communication data is effective or not, and when any condition occurs, the slave chip prepares to take over;

5) when the master chip actively requires the slave chip to take over, the corresponding take-over mark value is sent to the slave chip, and the slave chip recognizes the take-over mark value and prepares for take over;

6) the EPB sends CAN signals to the whole vehicle, and the CAN signals are sent by a chip which currently realizes the EPB function;

7) when the master chip and the slave chip both identify the fault that the EPB function can not be normally executed during the drive diagnosis, the slave chip requests the HMI to display to prompt the driver that the EPB function is invalid.

And (3) determining the state in the step (2) as the forward rotation of the EPB motor, judging whether the friction plate contacts the brake disc according to the fed-back motor current, then reversing the motor to a set caliper displacement, determining the state at the moment as a release state, and executing a normal clamping driving process when clamping needs to be executed.

In the process of taking over by the master chip and the slave chip, the time from the occurrence of the event for triggering the take-over to the completion of the take-over is less than 200 ms.

The main chip and the slave chip exchange data to realize redundant receiving and sending through serial port data and CAN data, wherein the serial port data exchange period is 10ms, and the CAN data exchange period is 20 ms.

The master chip and the slave chip have the functions of fault state, take-over mark, clamping force, clamping displacement, communication counting and communication check data according to interactive parameters, and have the functions of drive capability diagnosis, response EPB action judgment, EPB state judgment and interactive data transceiving besides normal function logic.

The invention has the beneficial effects that: the invention realizes the parking/parking function of the EPB slave chip, the master chip can realize all EPB functions in a fault-free state, the slave chip monitors whether the master chip works normally or not in real time, when the master chip fails in function or is abnormal in communication, the slave chip takes over the EPB function, and after the master chip recovers to be normal, the master chip realizes the EPB function again; the slave chip has an EPB function, can realize backup of manual parking, manual release, flameout automatic parking, P-gear automatic parking, intelligent parking, dynamic parking, degraded parking and re-clamping functions, and can be used for pure electric vehicles without a P-gear locking mechanism; before the master chip and the slave chip are switched, internal state data are interacted with each other, when the switching occurs, one of the master chip and the slave chip is responsible for judging the current EPB state and the caliper state, seamless switching is achieved, caliper state errors are avoided, the normal switching process is seamless, the maximum action time is prolonged to 200ms, and interference is not generated for a driver.

Drawings

FIG. 1 is a logic diagram of a master-slave chip according to the prior art.

FIG. 2 is a logic diagram of a master-slave chip according to the present invention.

Detailed Description

The invention will be described in detail below with reference to the following drawings:

as shown in the attached drawings, the coordination control method of the hot standby electronic parking brake system mainly comprises the following steps:

1) the master chip actively judges whether the drive is normal or not, whether the master chip can complete EPB action or not, and sends the data to the slave chip;

2) when the master chip and the slave chip start to execute the EPB action, judging the current state according to whether the previous action is executed by the master chip and whether the execution is normal or not, interacting with the opposite chip when the current state cannot be judged, confirming the execution condition of the opposite chip, and judging by additionally executing a state confirmation action if the current state cannot be judged; the state confirmation action is: the EPB motor rotates forwards, whether the friction plate contacts the brake disc or not is judged according to the fed-back motor current, then the motor rotates backwards to a set caliper displacement (release clearance), the state at the moment is confirmed to be a release state, and when the clamping needs to be executed, a normal clamping driving process is executed;

3) the slave chip firstly judges whether the slave chip is in a forbidden state, does not take over EPB in the forbidden state, and is used for updating the program of the master chip and other operations;

4) the slave chip judges whether the monitoring communication is overtime or not, whether the communication data is updated normally or not and whether the communication data is effective or not, and when any condition occurs, the slave chip prepares to take over;

5) when the master chip actively requires the slave chip to take over, the corresponding take-over mark value is sent to the slave chip, and the slave chip recognizes the take-over mark value and prepares for take over;

6) the EPB sends CAN signals to the whole vehicle, and the CAN signals are sent by a chip which currently realizes the EPB function;

7) when the master chip and the slave chip both identify the fault that the EPB function can not be normally executed during the drive diagnosis, the slave chip requests the HMI to display to prompt the driver that the EPB function is invalid.

In the process of taking over the main chip and the slave chip, the time from the occurrence of an event for triggering the taking over to the completion of the taking over is less than 200ms so as to meet the requirements of the reset time of the power supply chip and the drive chip. The main chip and the slave chip exchange data to realize redundant receiving and sending through serial port data and CAN data, wherein the serial port data exchange period is 10ms, and the CAN data exchange period is 20 ms. The master chip and the slave chip have the functions of fault state, take-over mark, clamping force, clamping displacement (release gap), communication counting, communication checking and the like according to interactive parameters, and have the functions of drive capability diagnosis, EPB action judgment whether to respond or not, EPB state judgment and interactive data transceiving besides normal functional logic.

According to the invention, by adding the motor driving function of the slave chip, when the EPB has single-circuit power supply failure, single-circuit driving failure, one of the master chip and the slave chip fails and the single-side electronic caliper fails, the EPB can still realize the functions of manual parking, manual release, flameout automatic parking, P-gear automatic parking, intelligent parking, dynamic parking, degraded parking, re-clamping and the like, the redundancy backup of the EPB function is realized, the safety of the EPB function is improved, and the requirement of a pure electric vehicle without a P-gear locking mechanism on an EPB product can be met; by adding the interaction logic of the master chip and the slave chip, the state of the EPB is effectively transferred when normal switching is realized (one party is invalid or forbidden, effective master-slave communication is carried out, and the other party normally takes over after the invalid), the switching process is seamless, interference is not generated to a driver, and the subjective feeling of the product function is better; by adding the state confirmation action logic, the required clamping/releasing action can still be correctly completed when the abnormal switching is performed in an extreme case.

It should be understood that equivalent substitutions and changes to the technical solution and the inventive concept of the present invention should be made by those skilled in the art to the protection scope of the appended claims.