Active pedestrian protection system and method of protection thereof

Abstract

The application discloses an active pedestrian protection system and a protection method thereof, and belongs to the technical field of automobile safety protection.The system comprises a PPS mechanism assembly, a hood lock mechanism assembly and an electronic control unit, the PPS mechanism assembly comprises an electric supporting rod, a PPS actuator, a PPS hinge and the like, the hood lock mechanism assembly is additionally provided with a hood lock ratchet, and the electronic control unit is installed in a front compartment cover of the automobile and electrically connected with each component.The motor with specific parameters is used as an executing mechanism to replace traditional gunpowder, the electric supporting rod is used to realize force unloading and electrically open and close the front cover, the component state is judged by means of a current threshold value and a Hall number, and the system can be automatically reset after collision triggering, and the front compartment cover does not need to be replaced.The protection system and the protection method improve the precision and safety of pedestrian protection, reduce the use cost, solve the problem that the existing technology needs to replace the front cover after deformation and damage caused by collision, and have a wide market prospect.

Description

Technical Field

[0001] This invention relates to the field of pedestrian protection technology for automobile hoods, specifically to an active pedestrian protection system and its protection method. Background Technology

[0002] With the continuous growth of car ownership, road traffic safety issues are becoming increasingly prominent. Pedestrians, as a vulnerable group on the road, have made collision protection one of the core research and development directions for automotive safety technology. The hood-mounted pedestrian protection system, as a key device for mitigating pedestrian collision injuries, directly affects pedestrian safety.

[0003] Existing hood pedestrian protection systems generally employ gunpowder-driven actuators. When a collision occurs in the front compartment of a car and the protection function is triggered, the instantaneous impact force generated by the detonation of gunpowder drives the hood to rise to buffer the collision energy. However, this technology still has the following insurmountable drawbacks: First, the impact of gunpowder detonation is difficult to control precisely, and the rise and speed of the hood are unstable, which may lead to poor cushioning effect or even cause secondary impact injuries to pedestrians due to excessive impact force. At the same time, the hood is irreversibly deformed after the collision and cannot be restored to normal in time. If the vehicle still needs to move, the damaged hood may fall off or affect the field of vision, posing an additional safety threat to surrounding pedestrians and vehicles.

[0004] Second: Gunpowder is a flammable and explosive hazardous material. During the production, transportation, storage and maintenance of vehicles, there is a safety risk of accidental explosion, which threatens the personal safety of operators and users. In addition, the existing system will completely damage the front cover after being triggered, and the vehicle will not be able to drive normally. If this occurs on highways or in emergency rescue scenarios, it may easily cause traffic congestion or secondary accidents.

[0005] Third: The hood must be replaced entirely after a collision. The manufacturing cost of the hood is high, and the labor cost of repair significantly increases the cost of vehicle use. At the same time, the scrapped hood is mostly made of metal or composite materials, which are difficult to recycle and reuse, resulting in resource waste and not in line with the industry development trend of low carbon and environmental protection.

[0006] To address the aforementioned issues, existing technologies, such as the active engine hood actuator, system, control method, maintenance method, and storage medium disclosed in Chinese Patent CN116176487A, solve the problem of high repair costs resulting from system malfunctions and are applied to provide pedestrian protection for front-opening engine hoods. The actuator includes an engine hood, an engine hood hinge, an engine hood lock, and an engine hood lifter. The engine hood hinge is located at the front end of the engine hood for rotating connection between the engine hood and the vehicle body. The engine hood lock is located at the rear end of the engine hood to lock it in a closed state. The engine hood lifter is located at the center of the rear end of the engine hood and, upon detonation, springs the rear end of the engine hood forward around the engine hood hinge axis. The method involves: a collision signal sensing module detecting a collision signal and sending it to the control module; the control module sending a command to the actuator to unlock the engine hood lock; and the engine hood lifter detonating, causing the rear end of the engine hood to spring up to the height limit set by the safety hook. The system uses a detonator, i.e., gunpowder-driven method to lift the hood, which has problems such as the need to replace the hood after triggering, safety hazards in gunpowder storage and use, and low accuracy in impact force control, which are consistent with the core defects of existing technologies.

[0007] For example, Chinese patent CN111003068A discloses a continuously operating active hood device connected to an advanced driver assistance system (ADAS). The device includes: an articulated arm connected to the vehicle's hood; a fixed bracket fixed to the vehicle body; and a rotating bracket configured to rotate about a pivot pin of the fixed bracket. A first link interconnects the rotating bracket and the articulated arm, and a main shaft is integrally connected to the rotating bracket. A controller receives vehicle driving information from the ADAS and adjusts the hood's pop-up height when a collision is anticipated based on the received driving information. Although this device achieves hood pop-up through the coordinated operation of the rotating bracket and the link, and is linked to the ADAS, it does not disclose the related structure and effect of "reuse reset," and it does not employ a motor drive, thus failing to solve the problem of "requiring component replacement after triggering" in existing technologies.

[0008] For example, Chinese patent CN114347944B discloses an active hood lifting system and control method, which is located under the hood and includes a first lifting mechanism, a second lifting mechanism, and a third lifting mechanism arranged in a three-point configuration. The first lifting mechanism is located at the front end of the hood, and the second and third lifting mechanisms are symmetrically arranged on both sides of the rear end of the hood. The first lifting mechanism includes a hood lock bracket and a drive unit arranged vertically and in transmission cooperation. The second lifting mechanism includes a first hood hinge assembly and a drive unit arranged vertically and in transmission cooperation. The third lifting mechanism includes a second hood hinge assembly and a drive unit arranged vertically and in transmission cooperation. The lower end of the hood lock bracket, the lower end of the first hood hinge assembly, and the lower end of the second hood hinge assembly are respectively provided with vertically arranged elongated holes. Each elongated hole is slidably connected to the vehicle body through a connector. This system and control method uses a three-point lifting mechanism and an electromagnet for driving. After lifting, it needs to rely on the electromagnet for reset, and there is no self-reset function of the motor. Moreover, the electromagnet's attraction force is limited, and it is prone to failure after long-term use, resulting in unstable reliability and safety. Summary of the Invention

[0009] Purpose of the invention: To address the shortcomings of existing technologies, this invention provides an active pedestrian protection system and its protection method. It uses a motor with specific parameters as the actuator to replace traditional gunpowder, and achieves force relief and electric switching functions through an electric support rod. Combined with precise state judgment logic, it solves many defects of existing technologies and has significant advantages in pedestrian protection effect, safety of use, and economy, with broad market application prospects.

[0010] Technical solution: In order to achieve the above objectives, the present invention provides an active pedestrian protection system, which includes a PPS mechanism assembly and an engine hood locking mechanism assembly connected to an electronic control unit. The active pedestrian protection system is applicable to both the structure with electric struts on both sides of the engine hood and the structure with an electric strut on one side of the engine hood and a balance strut on the other side. The PPS mechanism assembly includes an electric strut, a PPS actuator, a PPS hinge, a PPS hinge pawl, a PPS hinge ratchet, a PPS cable, and a locking rod. The electric strut is mounted on the PPS hinge. The PPS actuator is connected to the PPS hinge via the PPS cable. The PPS hinge pawl and PPS hinge ratchet are mounted on the PPS hinge. The locking rod is vertically fixed to the PPS hinge. The PPS actuator has a microswitch with a normally open contact (NO) and a normally closed contact (NC). When the PPS actuator returns to the zero position, the normally open contact of the microswitch is short-circuited. When the PPS actuator is not in the zero position, the normally open contact of the microswitch is open. The electronic control unit determines whether the PPS actuator has returned to the zero position by detecting the on / off state of the microswitch contacts.

[0011] The hood lock mechanism assembly includes a hood lock body, a hood lock actuator, a hood lock cable, and a hood lock ratchet. The hood lock actuator is connected to the hood lock body via the hood lock cable. The hood lock ratchet is installed in conjunction with the hood lock body. Since the connection between the hood lock ratchet and the hood lock body is a known existing technology widely used in the mechanical field, this structure will not be described in detail here. The unloading mode, opening mode, and closing mode of the electric strut are all known technologies, and this function is common knowledge; therefore, they will not be described in detail here. The electric strut can be purchased through e-commerce channels; the model is Frunk M30. The hood lock actuator has a microswitch inside. When the hood lock actuator returns to the zero position, the microswitch is in the open state; when the hood lock actuator is not in the zero position, the microswitch is in the short-circuited state. The electronic control unit determines whether the hood lock actuator has returned to the zero position by detecting the on / off state of the microswitch. The electronic control unit is installed inside the hood of the vehicle and is electrically connected to the electric strut, PPS actuator, and hood lock actuator, respectively. It is used to receive instructions from the advanced driver assistance system module and the body control module and control each component to perform corresponding actions.

[0012] As a further preferred embodiment of the present invention, the PPS actuator is a motor. The PPS actuator is used to drive the PPS pull wire to drive the PPS hinge to realize the opening or closing action, and the motor can rotate in the opposite direction to reset to the zero position.

[0013] As a further preferred embodiment of the present invention, the electric strut has a force-relieving mode, an opening mode, and a closing mode. The force-relieving mode is used to offset the reset impact force when the PPS hinge resets. The opening mode is used to drive the hood to open. The closing mode is used to drive the hood to close.

[0014] As a further preferred embodiment of the present invention, the PPS hinge pawl and the PPS hinge ratchet can be selectively engaged or disengaged. When engaged, the PPS hinge remains closed, and when disengaged, the PPS hinge can be opened. The PPS cable drives the PPS hinge ratchet to rotate clockwise or counterclockwise, which in turn drives the PPS hinge pawl to rotate and engage with or disengage from the locking bar, thus achieving the engagement or disengagement of the PPS hinge pawl from the locking bar. Since the ratchet and pawl working together to engage or disengage the pawl from the locking bar is existing technology and widely used in current mechanical structures, the working principle of this structure will not be described in detail.

[0015] As a further preferred embodiment of the present invention, the hood lock body has a fully locked position, a half-locked position, and a fully open position, and the hood lock actuator drives the hood lock body to switch between the three positions via the hood lock cable.

[0016] An active pedestrian protection method is applied to an active pedestrian protection system, including an active pedestrian protection system release process, an active pedestrian protection system reset process, a normal opening process for the car hood, and a normal closing process for the car hood. The active pedestrian protection system release process includes: the electronic control unit receives a collision warning signal from the advanced driver assistance system module, drives the hood lock to unlock to the half-lock position, controls the PPS actuator to work so as to drive the PPS hinge to open, and when the electronic control unit detects that the PPS actuator motor current exceeds the stall current threshold, it determines that the PPS hinge is fully open. Subsequently, after receiving a signal from the position sensor, the PPS actuator rotates in the opposite direction to reset to the zero position. The active pedestrian protection system reset process includes: the electronic control unit receives a reset command from the vehicle control module, which causes the electric strut to close after being de-stressed, drives the PPS hinge to close, and then controls the hood lock body to close to the full lock position; The normal opening process of the car hood includes: the electronic control unit receives the opening command from the body control module, drives the hood lock to unlock to the fully open position, controls the electric strut to drive the hood to open until it is fully open, and then cuts off the power to the electric strut; The normal closing process of the car hood includes: the electronic control unit receives the closing command from the body control module, controls the electric strut to drive the hood to close until it is fully closed, then cuts off the power to the electric strut, and then determines whether the hood lock is in the half-lock position. If so, it drives the hood to engage to the fully locked position.

[0017] As a further preferred embodiment of the present invention, in the release process of the active pedestrian protection system, after the PPS hinge is fully opened, the electronic control unit first cuts off the power supply to the PPS actuator, then controls the PPS actuator to rotate in the opposite direction back to the zero position, and cuts off the power supply to the PPS actuator again after returning to the zero position. At the same time, after the hood lock body is unlocked to the half-lock position, the hood lock actuator rotates in the opposite direction to reset to the zero position, and cuts off the power supply to the hood lock actuator after resetting. The electronic control unit determines whether the hood lock actuator has returned to the zero position by detecting the state of the normally open contact of the micro switch inside the PPS actuator. When the normally open contact is short-circuited, it is determined that the hood lock actuator has returned to the zero position. The electronic control unit determines whether the hood lock actuator has returned to the zero position by detecting the on / off state of the micro switch inside the hood lock actuator. When the micro switch is off, it is determined that the hood lock actuator has returned to the zero position.

[0018] As a further preferred embodiment of the present invention, in the reset process of the active pedestrian protection system, after the PPS hinge is fully closed, the electronic control unit first cuts off the power supply to the PPS actuator and the electric strut, then controls the PPS actuator to rotate in the opposite direction back to the zero position, and cuts off the power supply to the PPS actuator again after returning to the zero position; after the hood lock body is engaged to the fully locked position, the hood lock actuator rotates in the opposite direction to reset to the zero position, and cuts off the power supply to the hood lock actuator after reset. The electronic control unit determines whether the hood lock actuator has returned to the zero position by detecting the state of the normally open contact of the micro switch inside the PPS actuator. When the normally open contact is short-circuited, it is determined that the hood lock actuator has returned to the zero position; the electronic control unit determines whether the hood lock actuator has returned to the zero position by detecting the on / off state of the micro switch inside the hood lock actuator. When the micro switch is off, it is determined that the hood lock actuator has returned to the zero position.

[0019] As a further preferred embodiment of the present invention, in the normal opening process of the car hood, if the hood lock body is in the fully locked position, the electronic control unit first drives it to unlock to the half-lock position, the hood lock actuator resets to the zero position and then cuts off the power, then drives the hood lock body to unlock to the fully open position, the hood lock actuator resets to the zero position again and then cuts off the power, and then controls the electric strut to open. The electronic control unit determines whether the hood lock actuator has returned to the zero position by detecting the on / off state of the micro switch inside the hood lock actuator. When the micro switch is off, it is determined that the hood lock has been reset to the zero position.

[0020] As a further preferred embodiment of the present invention, in the normal closing process of the car hood, after the electric strut is fully closed and the power is cut off, the electronic control unit determines whether the hood lock body is in the half-lock position. If so, it drives it to engage to the fully locked position, and the hood lock actuator resets to the zero position before cutting off the power. If not, the electronic control unit does not perform subsequent actions. Specifically, the electronic control unit determines whether the hood lock actuator has returned to the zero position by detecting the on / off state of the microswitch inside the actuator; when the microswitch is off, it determines that the actuator has reset to the zero position.

[0021] Beneficial effects: Compared with the prior art, the active pedestrian protection system and method described in this invention have the following advantages: (1) The PPS actuator is used as the actuator to replace the traditional gunpowder to release the hood hinge, which avoids the safety hazards caused by the gunpowder explosion. The speed and force of the motor can be precisely controlled, and the opening range and speed of the PPS hinge can be precisely adjusted according to the collision scenario, which improves the effectiveness of pedestrian protection and reduces the risk of secondary injury. At the same time, the motor drive mode allows the system to reset automatically after being triggered, without the need to replace the hood, which reduces the cost of use and reduces the waste of resources. Both the PPS actuator and the hood lock actuator have built-in micro switches, which realize the accurate detection of the zero position state, providing a reliable judgment basis for the actuator reset action, and improving the accuracy and stability of the system reset. (2) An electric strut is installed so that it can perform a force relief operation when the PPS hinge is reset, which avoids damage to the components due to excessive force during the reset process, ensures the stability and reliability of the system reset, and extends the service life of the system; at the same time, the electric strut can realize the electric opening and closing of the front cover during normal operation, which improves the convenience of use and enhances the user experience. (3) The cooperation structure of the PPS hinge pawl and PPS hinge ratchet in the PPS mechanism assembly can ensure the stability and accuracy of the PPS hinge during opening and closing, avoid jamming or malfunction, and ensure the reliability of the system operation. (4) The hood lock mechanism assembly, through the cooperation of the hood lock actuator and the hood lock cable, realizes the precise switching of the hood lock between the fully locked, half-locked and fully open positions, meets the requirements of the hood lock position under different processes, and further improves the overall performance of the system; (5) As the control core of the system, the electronic control unit can quickly receive and process the instructions issued by the advanced driver assistance system module and the body control module, accurately control the coordinated work of each component, ensure the orderly progress of each process, improve the system's response speed and control accuracy. The electronic control unit can quickly determine the actuator zero position by detecting the on / off state / contact status of the micro switch. The detection method is simple and efficient, further improving the system's response efficiency. (6) In the release process, the lock body is unlocked first and then the hinge is opened. In the reset process, the force is released first and then the hinge and lock body are closed. In the normal switching process, the order of "state judgment, action execution, reset and power off" is followed to ensure that all components work together and improve the overall reliability of the system. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the release process of the active pedestrian protection system of the present invention; Figure 2 This is a schematic diagram of the reset process of the active pedestrian protection system of the present invention; Figure 3 This is a schematic diagram illustrating the normal opening process of a car hood according to the present invention; Figure 4 This is a schematic diagram of the normal closing process of the car hood according to the present invention; Figure 5 This is a schematic diagram of the PPS mechanism assembly structure of the present invention; Figure 6 This is a schematic diagram of the closed state of the PPS hinge of the present invention; Figure 7 This is a schematic diagram of the open state of the PPS hinge of the present invention; Figure 8 This is a schematic diagram of the hood locking mechanism assembly of the present invention; Figure 9This is a schematic diagram showing the fully locked position of the hood lock according to the present invention; Figure 10 This is a schematic diagram of the half-lock position of the hood lock according to the present invention; Figure 11 This is a schematic diagram of the fully open position of the hood lock according to the present invention. Detailed Implementation

[0023] The present invention will be further explained below with reference to the accompanying drawings and specific embodiments.

[0024] The present invention discloses an active pedestrian protection system, which is applicable to both the structure with electric struts on both sides of the hood and the structure with electric struts on one side of the hood and balance struts on the other side. It includes a PPS mechanism assembly 100 connected to an electronic control unit and a hood locking mechanism assembly 200. The PPS mechanism assembly 100 includes an electric strut 101, a PPS actuator 102, a PPS hinge 103, a PPS hinge pawl 104, a PPS hinge ratchet 105, a PPS cable 106, and a locking rod 107. The electric strut 101 is mounted on the PPS hinge 103. The PPS actuator 102 is connected to the PPS hinge 103 via the PPS cable 106. The locking rod 107 is vertically fixed on the PPS hinge 103. The PPS hinge pawl 104 and the PPS hinge ratchet 105 are fitted together and mounted on the PPS hinge 103. The PPS actuator 102 has a micro switch with a normally open contact NO and a normally closed contact NC. When the PPS actuator 102 returns to the zero position, the normally open contact of the micro switch is short-circuited; when the PPS actuator 102 is not in the zero position, the normally open contact of the micro switch is open. The electronic control unit determines whether the PPS actuator 102 has returned to the zero position by detecting the on / off state of the micro switch contacts.

[0025] The hood lock mechanism assembly 200 includes a hood lock body 201, a hood lock actuator 202, a hood lock cable 203, and a hood lock ratchet 204. The hood lock actuator 202 is connected to the hood lock body 201 via the hood lock cable 203, and the hood lock ratchet 204 is installed together with the hood lock body 201. The hood lock actuator 202 is equipped with a micro switch. When the hood lock actuator 202 returns to the zero position, the micro switch is in the open state. When the hood lock actuator 202 is not in the zero position, the micro switch is in the short-circuited state. The electronic control unit determines whether the hood lock actuator 202 has returned to the zero position by detecting the on / off state of the micro switch.

[0026] The electronic control unit is installed inside the hood of the vehicle and is electrically connected to the electric strut 101, PPS actuator 102, and hood lock actuator 202 respectively. It is used to receive instructions from the advanced driver assistance system module and the body control module and control each component to perform corresponding actions.

[0027] The PPS actuator 102 is a motor that drives the PPS pull wire 106 to drive the PPS hinge 103 to open or close. The motor can also rotate in the opposite direction to reset to the zero position.

[0028] The electric strut 101 has a stress-relieving mode, an opening mode, and a closing mode. The stress-relieving mode is used to counteract the reset impact force when the PPS hinge 103 resets. The opening mode is used to drive the hood to open. The closing mode is used to drive the hood to close.

[0029] The PPS hinge pawl 104 and the PPS hinge ratchet 105 can selectively engage or disengage. When engaged, the PPS hinge 103 remains closed. When disengaged, the PPS hinge 103 can open, and the PPS pull cable 106 drives the PPS hinge ratchet 105 to rotate forward or backward, thereby causing the PPS hinge pawl 104 to rotate and engage with or disengage from the locking bar 107, thus achieving engagement or disengagement between the PPS hinge pawl 104 and the locking bar 107.

[0030] The hood lock body 201 has a fully locked position, a half-locked position and a fully open position. The hood lock actuator 202 drives the hood lock body 201 to switch between the three positions via the hood lock cable 203. Example 1

[0031] The active pedestrian protection system is suitable for structures with motorized struts on both sides of the hood, as well as structures with a motorized strut on one side of the hood and a balance strut on the other. In this embodiment, motorized struts 101 are installed on the PPS hinges 103 on both sides of the hood, and both motorized struts 101 are electrically connected to the electronic control unit.

[0032] The PPS mechanism assembly 100 includes an electric strut 101, a PPS actuator 102, a PPS hinge 103, a PPS hinge pawl 104, a PPS hinge ratchet 105, and a PPS cable 106. The electric strut 101 is mounted on the PPS hinge 103. The PPS actuator 102 is connected to the PPS hinge 103 via the PPS cable 106. The PPS hinge pawl 104 and the PPS hinge ratchet 105 are fitted together and mounted on the PPS hinge 103.

[0033] The hood lock mechanism assembly 200 includes a hood lock body 201, a hood lock actuator 202, a hood lock cable 203, and a hood lock ratchet 204. The hood lock actuator 202 is connected to the hood lock body 201 via the hood lock cable 203, and the hood lock ratchet 204 is installed in conjunction with the hood lock body 201.

[0034] The electronic control unit is installed inside the hood of the vehicle and is electrically connected to the electric strut 101, PPS actuator 102, and hood lock actuator 202. It is used to receive commands from the advanced driver assistance system module and the body control module and control the various components to perform actions.

[0035] The electronic control unit receives instructions from the advanced driver assistance system module and the body control module, and precisely controls the synchronous movement of the electric struts 101 on both sides to ensure that the process of raising, resetting and opening the hood is smooth and uniform. It is suitable for use scenarios in mid-to-high-end vehicles where the requirements for support stability and control precision are high.

[0036] First, the specific working principle of the active pedestrian protection system release process: When the advanced driver assistance system (ADAS) module detects an impending collision risk while the vehicle is in motion, it sends a collision warning signal to the electronic control unit (ECU), which is a release command for the active pedestrian protection system. Upon receiving this command, the ECU first drives the hood lock actuator 202 to rotate. The hood lock actuator 202, via the hood lock cable 203, actuates the hood lock body 201, unlocking the hood lock from the fully locked position to the half-lock position, preparing for the opening of the PPS hinge 103. Subsequently, the ECU controls the PPS actuator 102 to move in the opening direction. The PPS actuator 102, via the PPS cable 106, pulls the PPS hinge 103, causing the PPS hinge pawl 104 on the PPS hinge 103 to disengage from the PPS hinge ratchet 105, and the PPS hinge 103 begins to open. The electronic control unit (ECU) monitors the opening status of the PPS hinge 103 in real time to determine if it is fully open. If not fully open, it continues to control the PPS actuator 102 to move in the opening direction. If fully open, the ECU cuts off the power to the PPS actuator 102 and then controls it to move in the closing direction. The ECU monitors the normally open contact status of the microswitch inside the PPS actuator 102 in real time. When it detects that the normally open contact is short-circuited, it determines that the PPS actuator 102 has returned to the zero position, and the ECU cuts off the power to the PPS actuator 102 again. Simultaneously, the hood lock actuator 202 rotates in the opposite direction. The ECU monitors the status of its internal microswitch. When the microswitch is open, it determines that the hood lock actuator 202 has returned to the zero position and cuts off its power, completing the release process. In this process, the fully open PPS hinge 103 raises the hood, thus providing a buffer for pedestrians in the event of a collision and reducing the injury suffered by pedestrians.

[0037] Second, the specific working principle of the active pedestrian protection system reset process: After the collision incident is handled, the user initiates a PPS hinge reset command from the vehicle control module to the electronic control unit (ECU) via relevant operations. Upon receiving this command, the ECU first controls the electric strut 101 to perform a stress-relieving action to prevent damage to components due to excessive force during subsequent reset. Simultaneously, it controls the PPS hinge 103 to perform a reset action. The ECU detects the stress-relieving status of the electric strut 101 to determine if stress relief is complete. If not, it continues to control the electric strut 101 to perform the stress-relieving action; if complete, the ECU controls the PPS actuator 102 to move in the closing direction. The PPS actuator 102, through the PPS cable 106, drives the PPS hinge 103, causing the PPS hinge pawl 104 and PPS hinge ratchet 105 to re-engage, and the PPS hinge 103 begins to close. The ECU detects whether the PPS hinge 103 is closed. If not, it continues to control the PPS actuator 102 to move in the closing direction; if closed, the ECU controls the electric strut 101 to perform the closing action. Simultaneously, the electronic control unit detects the reverse rotation of the PPS actuator 102 and checks the state of the normally open contact of its internal microswitch. When the normally open contact is short-circuited, it determines that the PPS actuator 102 has returned to the zero position. If it has not returned to the zero position, it controls the PPS actuator 102 to move in the opening direction and then attempts to close the PPS hinge 103 again. If it has returned to the zero position, the electronic control unit cuts off the power to the PPS actuator 102 and the electric strut 101. Afterward, the electronic control unit drives the hood lock actuator 202 to rotate, which in turn drives the hood lock body 201 to move through the hood lock cable 203, causing the hood lock to self-lock from the half-lock position to the fully locked position. Subsequently, the electronic control unit controls the hood lock actuator 202 to rotate in the opposite direction, checks the state of its internal microswitch, and determines that it has returned to the zero position when the microswitch is open, and cuts off the power to the hood lock actuator 202, thus completing the reset process.

[0038] Third, the specific working principle of the normal opening procedure of a car hood: When a user needs to open the hood for maintenance or other operations, they issue a hood-opening command through the vehicle control module. Upon receiving this command, the electronic control unit (ECU) first determines whether the hood is currently in the open position. If the hood is already open, the ECU does not issue any action command; if the hood is closed, the ECU further determines whether the hood lock is in the fully open position. If the hood lock is in the fully open position, the electronic control unit directly controls the electric strut 101 to perform the opening action. The electric strut 101 extends to push the hood open until it is fully open, at which point the electronic control unit cuts off the power to the electric strut 101. If the hood lock is not in the fully open position, the electronic control unit first drives the hood lock actuator 202 to rotate, which in turn drives the hood lock body 201 to unlock from its current position (fully locked or half locked) to the fully open position via the hood lock cable 203. Then, the electronic control unit controls the hood lock actuator 202 to rotate in the opposite direction. The electronic control unit detects the status of its internal microswitch. When the microswitch is disconnected, it determines that the hood has returned to the zero position. After that, the electronic control unit controls the electric strut 101 to perform the opening action until it is fully open, at which point the electronic control unit cuts off the power to the electric strut 101, and the normal opening process is completed.

[0039] Fourth, the specific working principle of the normal closing procedure of a car hood: After the user completes the maintenance, a hood-closing command is issued via the vehicle control module. Upon receiving this command, the electronic control unit (ECU) first determines whether the hood is currently in the open position. If the hood is in the closed position, the ECU does not issue any action command. If the hood is in the open position, the ECU controls the electric strut 101 to perform the closing action, causing the electric strut 101 to retract and gradually close the hood. The ECU then checks whether the electric strut 101 is fully closed. If it is not fully closed, the ECU continues to control the electric strut 101 to perform the closing action. If it is fully closed, the ECU cuts off the power to the electric strut 101 and then determines whether the hood lock is in the half-lock position. If the hood lock is not in the half-lock position, the electronic control unit does not operate; if the hood lock is in the half-lock position, the electronic control unit controls the hood lock actuator 202 to rotate, which drives the hood lock body 201 from the half-lock position to the fully closed position through the hood lock cable 203. Then, the electronic control unit controls the hood lock actuator 202 to rotate in the opposite direction, detects the status of its internal microswitch, and determines that it has returned to the zero position when the microswitch is open, and cuts off the power to the hood lock actuator 202, thus completing the normal closing process.

[0040] Example 2

[0041] The active pedestrian protection system is suitable for structures with motorized struts on both sides of the hood, as well as structures with a motorized strut on one side of the hood and a counterweight strut on the other. A motorized strut 101 is mounted on the PPS hinge 103 on one side of the hood and is electrically connected to the electronic control unit. A conventional counterweight strut is mounted on the PPS hinge 103 on the other side of the hood and is not connected to the electronic control system.

[0042] The PPS actuator 102 is a motor with a micro switch inside that has a normally open contact NO and a normally closed contact NC. The electronic control unit determines whether the PPS actuator 102 has returned to the zero position by detecting the on / off state of the contacts.

[0043] During system release, reset, and normal opening and closing of the hood, the electric strut 101 performs driving and unloading actions, and the balance strut provides follow-up auxiliary support. This reduces hardware costs without changing the original control logic or affecting the protection effect, making it suitable for mass installation in economy passenger cars and compact models.

[0044] First, the specific working principle of the active pedestrian protection system release process: When the advanced driver assistance system (ADAS) module detects an impending collision risk while the vehicle is in motion, it sends a collision warning signal to the electronic control unit (ECU), which is a release command for the active pedestrian protection system. Upon receiving this command, the ECU first drives the hood lock actuator 202 to rotate. The hood lock actuator 202, via the hood lock cable 203, actuates the hood lock body 201, unlocking the hood lock from the fully locked position to the half-lock position, preparing for the opening of the PPS hinge 103. Subsequently, the ECU controls the PPS actuator 102 to move in the opening direction. The PPS actuator 102, via the PPS cable 106, pulls the PPS hinge 103, causing the PPS hinge pawl 104 on the PPS hinge 103 to disengage from the PPS hinge ratchet 105, and the PPS hinge 103 begins to open. The electronic control unit (ECU) monitors the opening status of the PPS hinge 103 in real time to determine if it is fully open. If not fully open, it continues to control the PPS actuator 102 to move in the opening direction. If fully open, the ECU cuts off the power to the PPS actuator 102 and then controls it to move in the closing direction. The ECU monitors the normally open contact status of the microswitch inside the PPS actuator 102 in real time. When it detects that the normally open contact is short-circuited, it determines that the PPS actuator 102 has returned to the zero position, and the ECU cuts off the power to the PPS actuator 102 again. Simultaneously, the hood lock actuator 202 rotates in the opposite direction. The ECU monitors the status of its internal microswitch. When the microswitch is open, it determines that the hood lock actuator 202 has returned to the zero position and cuts off its power, completing the release process. In this process, the fully open PPS hinge 103 raises the hood, thus providing a buffer for pedestrians in the event of a collision and reducing the injury suffered by pedestrians.

[0045] Second, the specific working principle of the active pedestrian protection system reset process: After the collision incident is handled, the user initiates a PPS hinge reset command from the vehicle control module to the electronic control unit (ECU) via relevant operations. Upon receiving this command, the ECU first controls the electric strut 101 to perform a stress-relieving action to prevent damage to components due to excessive force during subsequent reset. Simultaneously, it controls the PPS hinge 103 to perform a reset action. The ECU detects the stress-relieving status of the electric strut 101 to determine if stress relief is complete. If not, it continues to control the electric strut 101 to perform the stress-relieving action; if complete, the ECU controls the PPS actuator 102 to move in the closing direction. The PPS actuator 102, through the PPS cable 106, drives the PPS hinge 103, causing the PPS hinge pawl 104 and PPS hinge ratchet 105 to re-engage, and the PPS hinge 103 begins to close. The ECU detects whether the PPS hinge 103 is closed. If not, it continues to control the PPS actuator 102 to move in the closing direction; if closed, the ECU controls the electric strut 101 to perform the closing action. Simultaneously, the electronic control unit detects the reverse rotation of the PPS actuator 102 and checks the state of the normally open contact of its internal microswitch. When the normally open contact is short-circuited, it determines that the PPS actuator 102 has returned to the zero position. If it has not returned to the zero position, it controls the PPS actuator 102 to move in the opening direction and then attempts to close the PPS hinge 103 again. If it has returned to the zero position, the electronic control unit cuts off the power to the PPS actuator 102 and the electric strut 101. Afterward, the electronic control unit drives the hood lock actuator 202 to rotate, which in turn drives the hood lock body 201 to move through the hood lock cable 203, causing the hood lock to self-lock from the half-lock position to the fully locked position. Subsequently, the electronic control unit controls the hood lock actuator 202 to rotate in the opposite direction, checks the state of its internal microswitch, and determines that it has returned to the zero position when the microswitch is open, and cuts off the power to the hood lock actuator 202, thus completing the reset process.

[0046] Third, the specific working principle of the normal opening procedure of a car hood: When a user needs to open the hood for maintenance or other operations, they issue a hood-opening command through the vehicle control module. Upon receiving this command, the electronic control unit (ECU) first determines whether the hood is currently in the open position. If the hood is already open, the ECU does not issue any action command; if the hood is closed, the ECU further determines whether the hood lock is in the fully open position. If the hood lock is in the fully open position, the electronic control unit directly controls the electric strut 101 to perform the opening action. The electric strut 101 extends to push the hood open until it is fully open, at which point the electronic control unit cuts off the power to the electric strut 101. If the hood lock is not in the fully open position, the electronic control unit first drives the hood lock actuator 202 to rotate, which in turn drives the hood lock body 201 to unlock from its current position (fully locked or half locked) to the fully open position via the hood lock cable 203. Then, the electronic control unit controls the hood lock actuator 202 to rotate in the opposite direction. The electronic control unit detects the status of its internal microswitch. When the microswitch is disconnected, it determines that the hood has returned to the zero position. After that, the electronic control unit controls the electric strut 101 to perform the opening action until it is fully open, at which point the electronic control unit cuts off the power to the electric strut 101, and the normal opening process is completed.

[0047] Fourth, the specific working principle of the normal closing procedure of a car hood: After the user completes the maintenance, a hood-closing command is issued via the vehicle control module. Upon receiving this command, the electronic control unit (ECU) first determines whether the hood is currently in the open position. If the hood is in the closed position, the ECU does not issue any action command. If the hood is in the open position, the ECU controls the electric strut 101 to perform the closing action, causing the electric strut 101 to retract and gradually close the hood. The ECU then checks whether the electric strut 101 is fully closed. If it is not fully closed, the ECU continues to control the electric strut 101 to perform the closing action. If it is fully closed, the ECU cuts off the power to the electric strut 101 and then determines whether the hood lock is in the half-lock position. If the hood lock is not in the half-lock position, the electronic control unit does not operate; if the hood lock is in the half-lock position, the electronic control unit controls the hood lock actuator 202 to rotate, which drives the hood lock body 201 from the half-lock position to the fully closed position through the hood lock cable 203. Then, the electronic control unit controls the hood lock actuator 202 to rotate in the opposite direction, detects the status of its internal microswitch, and determines that it has returned to the zero position when the microswitch is open, and cuts off the power to the hood lock actuator 202, thus completing the normal closing process.

[0048] Example 3

[0049] The active pedestrian protection method is applicable to both active pedestrian protection systems with electric struts on both sides of the hood and active pedestrian protection systems with an electric strut on one side of the hood and a counterweight strut on the other side. The hood can be configured with electric struts 101 installed on both sides, or with an electric strut 101 installed on one side and a conventional counterweight strut installed on the other side; in this configuration, only the electric struts 101 are electrically connected to the electronic control unit, while the counterweight struts only provide follow-up support and are not connected to the electronic control system.

[0050] The PPS mechanism assembly 100 includes an electric strut 101, a PPS actuator 102, a PPS hinge 103, a PPS hinge pawl 104, a PPS hinge ratchet 105, and a PPS cable 106. The electric strut 101 is mounted on the PPS hinge 103. The PPS actuator 102 is connected to the PPS hinge 103 via the PPS cable 106. The PPS hinge pawl 104 and the PPS hinge ratchet 105 are fitted together and mounted on the PPS hinge 103.

[0051] The hood lock mechanism assembly 200 includes a hood lock body 201, a hood lock actuator 202, a hood lock cable 203, and a hood lock ratchet 204. The hood lock actuator 202 is connected to the hood lock body 201 via the hood lock cable 203, and the hood lock ratchet 204 is installed together with the hood lock body 201.

[0052] The electronic control unit is installed inside the hood of the vehicle and is electrically connected to the electric strut 101, PPS actuator 102, and hood lock actuator 202, respectively. It is used to receive instructions from the advanced driver assistance system module and the body control module and control each component to perform corresponding actions.

[0053] The PPS actuator 102 is a motor used to drive the PPS cable 106 to drive the PPS hinge 103 to open or close. The motor can also rotate in the opposite direction to reset to the zero position. The electric strut 101 has a load-bearing mode, an opening mode, and a closing mode. The PPS hinge pawl 104 and the PPS hinge ratchet 105 can be selectively engaged or disengaged. The hood lock body 201 has a fully locked position, a half-locked position, and a fully open position.

[0054] First, the specific working principle of the active pedestrian protection system release process: When the advanced driver assistance system (ADAS) module detects an impending collision risk while the vehicle is in motion, it sends a collision warning signal to the electronic control unit (ECU), which is a release command for the active pedestrian protection system. Upon receiving this command, the ECU first drives the hood lock actuator 202 to rotate. The hood lock actuator 202, via the hood lock cable 203, actuates the hood lock body 201, unlocking the hood lock from the fully locked position to the half-lock position, preparing for the opening of the PPS hinge 103. Subsequently, the ECU controls the PPS actuator 102 to move in the opening direction. The PPS actuator 102, via the PPS cable 106, pulls the PPS hinge 103, causing the PPS hinge pawl 104 on the PPS hinge 103 to disengage from the PPS hinge ratchet 105, and the PPS hinge 103 begins to open. The electronic control unit (ECU) monitors the opening status of the PPS hinge 103 in real time to determine if it is fully open. If not fully open, it continues to control the PPS actuator 102 to move in the opening direction. If fully open, the ECU cuts off the power to the PPS actuator 102 and then controls it to move in the closing direction. The ECU monitors the normally open contact status of the microswitch inside the PPS actuator 102 in real time. When it detects that the normally open contact is short-circuited, it determines that the PPS actuator 102 has returned to the zero position, and the ECU cuts off the power to the PPS actuator 102 again. Simultaneously, the hood lock actuator 202 rotates in the opposite direction. The ECU monitors the status of its internal microswitch. When the microswitch is open, it determines that the hood lock actuator 202 has returned to the zero position and cuts off its power, completing the release process. In this process, the fully open PPS hinge 103 raises the hood, thus providing a buffer for pedestrians in the event of a collision and reducing the injury suffered by pedestrians.

[0055] Second, the specific working principle of the active pedestrian protection system reset process: After the collision incident is handled, the user initiates a PPS hinge reset command from the vehicle control module to the electronic control unit (ECU) via relevant operations. Upon receiving this command, the ECU first controls the electric strut 101 to perform a stress-relieving action to prevent damage to components due to excessive force during subsequent reset. Simultaneously, it controls the PPS hinge 103 to perform a reset action. The ECU detects the stress-relieving status of the electric strut 101 to determine if stress relief is complete. If not, it continues to control the electric strut 101 to perform the stress-relieving action; if complete, the ECU controls the PPS actuator 102 to move in the closing direction. The PPS actuator 102, through the PPS cable 106, drives the PPS hinge 103, causing the PPS hinge pawl 104 and PPS hinge ratchet 105 to re-engage, and the PPS hinge 103 begins to close. The ECU detects whether the PPS hinge 103 is closed. If not, it continues to control the PPS actuator 102 to move in the closing direction; if closed, the ECU controls the electric strut 101 to perform the closing action. Simultaneously, the electronic control unit detects the reverse rotation of the PPS actuator 102 and checks the state of the normally open contact of its internal microswitch. When the normally open contact is short-circuited, it determines that the PPS actuator 102 has returned to the zero position. If it has not returned to the zero position, it controls the PPS actuator 102 to move in the opening direction and then attempts to close the PPS hinge 103 again. If it has returned to the zero position, the electronic control unit cuts off the power to the PPS actuator 102 and the electric strut 101. Afterward, the electronic control unit drives the hood lock actuator 202 to rotate, which in turn drives the hood lock body 201 to move through the hood lock cable 203, causing the hood lock to self-lock from the half-lock position to the fully locked position. Subsequently, the electronic control unit controls the hood lock actuator 202 to rotate in the opposite direction, checks the state of its internal microswitch, and determines that it has returned to the zero position when the microswitch is open, and cuts off the power to the hood lock actuator 202, thus completing the reset process.

[0056] Third, the specific working principle of the normal opening procedure of a car hood: When a user needs to open the hood for maintenance or other operations, they issue a hood-opening command through the vehicle control module. Upon receiving this command, the electronic control unit (ECU) first determines whether the hood is currently in the open position. If the hood is already open, the ECU does not issue any action command; if the hood is closed, the ECU further determines whether the hood lock is in the fully open position. If the hood lock is in the fully open position, the electronic control unit directly controls the electric strut 101 to perform the opening action. The electric strut 101 extends to push the hood open until it is fully open, at which point the electronic control unit cuts off the power to the electric strut 101. If the hood lock is not in the fully open position, the electronic control unit first drives the hood lock actuator 202 to rotate, which in turn drives the hood lock body 201 to unlock from its current position (fully locked or half locked) to the fully open position via the hood lock cable 203. Then, the electronic control unit controls the hood lock actuator 202 to rotate in the opposite direction. The electronic control unit detects the status of its internal microswitch. When the microswitch is disconnected, it determines that the hood has returned to the zero position. After that, the electronic control unit controls the electric strut 101 to perform the opening action until it is fully open, at which point the electronic control unit cuts off the power to the electric strut 101, and the normal opening process is completed.

[0057] Fourth, the specific working principle of the normal closing procedure of a car hood: After the user completes the maintenance, a hood-closing command is issued via the vehicle control module. Upon receiving this command, the electronic control unit (ECU) first determines whether the hood is currently in the open position. If the hood is in the closed position, the ECU does not issue any action command. If the hood is in the open position, the ECU controls the electric strut 101 to perform the closing action, causing the electric strut 101 to retract and gradually close the hood. The ECU then checks whether the electric strut 101 is fully closed. If it is not fully closed, the ECU continues to control the electric strut 101 to perform the closing action. If it is fully closed, the ECU cuts off the power to the electric strut 101 and then determines whether the hood lock is in the half-lock position. If the hood lock is not in the half-lock position, the electronic control unit does not operate; if the hood lock is in the half-lock position, the electronic control unit controls the hood lock actuator 202 to rotate, which drives the hood lock body 201 from the half-lock position to the fully closed position through the hood lock cable 203. Then, the electronic control unit controls the hood lock actuator 202 to rotate in the opposite direction, detects the status of its internal microswitch, and determines that it has returned to the zero position when the microswitch is open, and cuts off the power to the hood lock actuator 202, thus completing the normal closing process.

[0058] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. An active pedestrian protection system, characterized in that, It includes a PPS mechanism assembly (100) connected to an electronic control unit and a hood locking mechanism assembly (200). The active pedestrian protection system is applicable to both the structure with electric struts on both sides of the hood and the structure with electric struts on one side of the hood and balance struts on the other side. The PPS mechanism assembly (100) includes an electric strut (101), a PPS actuator (102), a PPS hinge (103), a PPS hinge pawl (104), a PPS hinge ratchet (105), a PPS cable (106), and a locking rod (107). The electric strut (101) is mounted on the PPS hinge (103), the PPS actuator (102) is connected to the PPS hinge (103) through the PPS cable (106), the locking rod (107) is vertically fixed on the PPS hinge (103), and the PPS hinge pawl (104) and the PPS hinge ratchet (105) are fitted together and mounted on the PPS hinge (103). The hood lock mechanism assembly (200) includes a hood lock body (201), a hood lock actuator (202), a hood lock cable (203), and a hood lock ratchet (204). The hood lock actuator (202) is connected to the hood lock body (201) via the hood lock cable (203), and the hood lock ratchet (204) is installed together with the hood lock body (201). The electronic control unit is installed inside the hood of the vehicle and is electrically connected to the electric strut (101), PPS actuator (102), and hood lock actuator (202) respectively. It is used to receive instructions from the advanced driver assistance system module and the body control module and control each component to perform corresponding actions.

2. The active pedestrian protection system according to claim 1, characterized in that, The PPS actuator (102) is a motor. The PPS actuator (102) is used to drive the PPS pull wire (106) to drive the PPS hinge (103) to achieve the opening or closing action. The motor can rotate in the opposite direction to reset to the zero position. The PPS actuator (102) is equipped with a micro switch with a normally open contact NO and a normally closed contact NC. When the PPS actuator (102) returns to the zero position, the normally open contact of the micro switch is in a short-circuited state; when the PPS actuator (102) is not in the zero position, the normally open contact of the micro switch is in an open state. The electronic control unit determines whether the PPS actuator (102) has returned to the zero position by detecting the on / off state of the micro switch contact.

3. The active pedestrian protection system according to claim 1, characterized in that, The electric strut (101) has a stress relief mode, an opening mode and a closing mode. The stress relief mode is used to counteract the reset impact force when the PPS hinge (103) is reset. The opening mode is used to drive the hood to open. The closing mode is used to drive the hood to close.

4. The active pedestrian protection system according to claim 1, characterized in that, The PPS hinge pawl (104) and the locking bar (107) can selectively abut or disengage. When abutting, the PPS hinge (103) remains closed, and when disengaged, the PPS hinge (103) can be opened. The PPS pull cable (106) drives the PPS hinge ratchet (105) to rotate forward or backward, thereby driving the PPS hinge pawl (104) to rotate and lock onto or disengage from the locking bar (107), thus achieving the mutual contact or disengagement of the PPS hinge pawl (104) from the locking bar (107).

5. The active pedestrian protection system according to claim 1, characterized in that, The hood lock body (201) has a fully locked position, a half-locked position and a fully open position. The hood lock actuator (202) drives the hood lock body (201) to switch between the three positions through the hood lock cable (203). The hood lock actuator (202) is equipped with a micro switch. When the hood lock actuator (202) returns to the zero position, the micro switch is in the open state. When the hood lock actuator (202) is not in the zero position, the micro switch is in the short-circuit state. The electronic control unit determines whether the hood lock actuator (202) has returned to the zero position by detecting the on / off state of the micro switch.

6. An active pedestrian protection method, characterized in that, The active pedestrian protection system described in any one of claims 1-5 includes an active pedestrian protection system release process, an active pedestrian protection system reset process, a normal opening process for the car hood, and a normal closing process for the car hood. The active pedestrian protection system release process includes: the electronic control unit receives a collision warning signal from the advanced driver assistance system module, drives the hood lock body (201) to unlock to the half-lock position, controls the PPS actuator (102) to drive and work so that the PPS hinge (103) opens, when the electronic control unit detects that the motor current of the PPS actuator (102) exceeds the stall current threshold, it determines that the PPS hinge (103) is fully opened, and the PPS actuator (102) receives a signal from the position sensor and rotates in the opposite direction to reset to the zero position; The active pedestrian protection system reset process includes: the electronic control unit receives the reset command from the vehicle control module, causes the control electric strut (101) to be de-stressed and closed, drives the PPS hinge (103) to close, and then controls the hood lock body (201) to be engaged to the fully locked position; The normal opening process of the car hood includes: the electronic control unit receives the opening command from the body control module, drives the hood lock body (201) to unlock to the fully open position, controls the electric strut (101) to drive the hood to open until it is fully open, and then cuts off the power to the electric strut (101). The normal closing process of the car hood includes: the electronic control unit receives the closing command from the body control module, controls the electric strut (101) to drive the hood to close until it is completely closed, then cuts off the power to the electric strut (101), and then determines whether the hood lock body (201) is in the half-lock position. If so, it is driven to engage to the full-lock position.

7. The active pedestrian protection method according to claim 6, characterized in that, In the active pedestrian protection system release process, after the PPS hinge (103) is fully opened, the electronic control unit first cuts off the power supply to the PPS actuator (102), and then controls the PPS actuator (102) to rotate in the opposite direction. The electronic control unit determines whether the PPS actuator (102) has returned to the zero position by detecting the state of the normally open contact of the micro switch inside the PPS actuator (102). When the normally open contact is in the short-circuit state, it is determined that the PPS actuator (102) has returned to the zero position. After returning to the zero position, the power supply to the PPS actuator (102) is cut off again. At the same time, after the hood lock body (201) is unlocked to the half-lock position, the hood lock actuator (202) rotates in the opposite direction. The electronic control unit determines whether the hood lock actuator (202) has returned to the zero position by detecting the on / off state of the micro switch inside the hood lock actuator (202). When the micro switch is in the off state, it is determined that the hood lock actuator (202) has returned to the zero position. After resetting to the zero position, the power supply to the hood lock actuator (202) is cut off.

8. The active pedestrian protection method according to claim 6, characterized in that, In the reset process of the active pedestrian protection system, after the PPS hinge (103) is completely closed, the electronic control unit first cuts off the power supply to the PPS actuator (102) and the electric strut (101), and then controls the PPS actuator (102) to rotate in the opposite direction. The electronic control unit determines whether the PPS actuator (102) has returned to the zero position by detecting the state of the normally open contact of the micro switch inside the PPS actuator (102). When the normally open contact is in the short-circuit state, it is determined that the PPS actuator (102) has returned to the zero position. After returning to the zero position, the power supply to the PPS actuator (102) is cut off again. After the hood lock body (201) is engaged to the fully locked position, the hood lock actuator (202) rotates in the opposite direction. The electronic control unit determines whether the hood lock actuator (202) has returned to the zero position by detecting the on / off state of the micro switch inside the hood lock actuator (202). When the micro switch is in the off state, it is determined that the hood lock actuator (202) has returned to the zero position. After reset, the power supply to the hood lock actuator (202) is cut off.

9. The active pedestrian protection method according to claim 6, characterized in that, In the normal opening process of the car hood, if the hood lock body (201) is in the fully locked position, the electronic control unit first drives it to unlock to the half-lock position, and the hood lock actuator (202) rotates in the opposite direction. The electronic control unit determines whether it has returned to the zero position by detecting the on / off state of the micro switch inside the hood lock actuator (202). When the micro switch is in the off state, it is determined that it has returned to the zero position. After resetting to the zero position, the power is cut off. Then, the hood lock body (201) is driven to unlock to the fully open position, and the hood lock actuator (202) rotates in the opposite direction again. The electronic control unit determines that it has returned to the zero position by detecting the on / off state of the micro switch. After resetting to the zero position, the power is cut off, and then the electric support rod (101) is controlled to open.

10. The active pedestrian protection method according to claim 6, characterized in that, In the normal closing process of the car hood, after the electric strut (101) is fully closed and the power is cut off, the electronic control unit determines whether the hood lock body (201) is in the half-lock position. If so, it drives the hood lock actuator (202) to be fully locked. The hood lock actuator (202) rotates in the opposite direction. The electronic control unit determines whether the hood lock actuator (202) has returned to the zero position by detecting the on / off state of the micro switch inside the hood lock actuator (202). When the micro switch is in the off state, it is determined that the hood has returned to the zero position. After resetting to the zero position, the power is cut off. If not, the electronic control unit does not perform subsequent actions.

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