Secondary collision avoidance control system and control method for vehicle driven by hub motor
The secondary collision avoidance control system driven by the wheel hub motor uses sensors and control modules to assess the vehicle's state and environment, select the appropriate avoidance mode, and achieve active steering and avoidance of the vehicle. This solves the problem that existing technologies cannot avoid secondary collisions and reduces the harm of chain-reaction rear-end collisions.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-27
- Publication Date
- 2026-03-24
AI Technical Summary
Existing vehicle safety technologies cannot effectively avoid secondary collisions that may occur after the first collision, especially when a passenger vehicle is sandwiched between the front and rear, which can cause serious injury to the driver, and lacks an active avoidance system.
The secondary collision avoidance control system for vehicles driven by hub motors includes collision detection sensors, environmental perception sensors, vehicle status sensors, and a control module. By assessing the vehicle's damage status and the surrounding traffic environment in real time, it selects active avoidance, limited avoidance, or attitude fine-tuning modes, and uses tire load rate and differential braking to achieve vehicle steering and avoidance.
It effectively reduces the harm of chain-reaction rear-end collisions and ensures driver safety by enabling vehicles to actively avoid collisions through intelligent assessment and path planning, thereby reducing secondary collision injuries.
Smart Images
Figure CN121716698A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the field of vehicle collision avoidance safety technology, and particularly relates to a secondary collision avoidance control system and control method for a wheel hub motor driven vehicle. BACKGROUND
[0002] In the field of automotive engineering, passive and active safety technology for vehicles has always been the core research direction in the field of automotive engineering, and the fundamental purpose is to protect the safety of passengers in the vehicle. At present, the anti-collision technology of the vehicle focuses on ensuring the safety of the driver when the vehicle collides for the first time, such as AEB (automatic emergency brake system), airbag, safety belt, and high-strength vehicle body structure and collision energy absorption zone.
[0003] Although the above-mentioned technology is very mature and has ensured the safety of the driver to a great extent, in a chain rear-end accident, the above-mentioned technology cannot fully play its function, especially when the current vehicle is sandwiched by passenger cars in front and back, the harm to the driver is more serious. That is, the existing vehicle safety technology forms a system of anti-collision (before collision) and collision (in collision), but lacks a secondary collision avoidance system after the first collision. How to make the vehicle actively and intelligently avoid the more deadly secondary collision after the first collision has become a technical blank that needs to be solved. SUMMARY
[0004] The present application aims at the deficiencies in the prior art, and provides a secondary collision avoidance control system and control method for a wheel hub motor driven vehicle. When the vehicle collides, the secondary collision avoidance system of the vehicle is urgently started to avoid secondary injury to the driver.
[0005] The present application provides the following technical solution, a secondary collision avoidance control system for a wheel hub motor driven vehicle, comprising a collision detection sensor, an environment perception sensor, a vehicle state sensor, and a control module.
[0006] The collision detection sensor comprises an airbag collision sensor and an acceleration sensor, which are used to determine that the first rear-end collision has occurred. The environment perception sensor comprises a rear radar and / or camera, and left and right side radars and / or cameras, which are used to obtain peripheral traffic environment information including road information, traffic flow information, distance between the rear vehicle and the current vehicle, and left and right side avoidable distance. The vehicle state sensor comprises an inertial measurement unit, a wheel speed sensor, and a steering wheel angle sensor, which are used to obtain vehicle state information including vehicle attitude, vehicle turning angle, wheel speed, yaw angular velocity, and longitudinal speed. The control module is used to receive output signals from the collision detection sensor, the environmental perception sensor and the vehicle status sensor, and select the corresponding avoidance mode according to the current damage status of the vehicle and the surrounding traffic environment information. The avoidance modes include active avoidance mode, restricted avoidance mode and attitude fine-tuning mode.
[0007] Furthermore, this invention also proposes a control method based on the above-mentioned secondary collision avoidance control system, comprising the following steps: The collision detection sensor detects whether a first rear-end collision has occurred. If so, the secondary collision avoidance control system is immediately activated. After the control system is activated, it performs self-checks on the power system, steering system, and sensors through vehicle status sensors and feedback signals from various actuators to assess the current damage status of the vehicle. Select the appropriate avoidance mode based on the current damage status of the vehicle: If the vehicle's powertrain and steering systems are functioning normally, and the system is deemed capable of performing comprehensive active steering avoidance, then it enters active avoidance mode. If the vehicle's powertrain or steering system is partially damaged, it will enter a restricted avoidance mode; such partial damage includes reduced output power and delayed steering response. If the vehicle's powertrain or steering system partially fails, it will enter a fine-tuning mode; such partial failures include steering jamming and insufficient power. Perform the corresponding avoidance operation for the selected avoidance mode to complete the secondary collision avoidance.
[0008] As a preferred embodiment, assessing the current damage status of the vehicle includes: determining whether the vehicle's turning angle is consistent with the vehicle's desired turning angle; if not, determining that the steer-by-wire system has failed and activating redundant control to achieve vehicle steering.
[0009] As a preferred embodiment, in the active avoidance mode, when distributing the driving torque of the left and right wheels with the objective function of minimizing the tire load rate, the vehicle dynamics constraints must be met.
[0010] As a preferred embodiment, in the restricted avoidance mode, when distributing the driving torque of the left and right wheels with the objective function of minimizing the tire load rate, it is necessary to meet the vehicle dynamics constraints and the drive motor output torque limit conditions.
[0011] As a preferred option, the active avoidance mode includes the following: Risk assessment is conducted based on surrounding traffic environment information, including a chain-reaction rear-end collision risk assessment. and avoidance space risk assessment , :
[0012]
[0013] In the formula, L is the speed of the following vehicle; L is the distance between the following vehicle and the current vehicle. This refers to the acceleration of the following vehicle; The maximum acceleration that the current road surface can provide; These represent the traffic speeds on the left and right sides, respectively. These are the predicted avoidable distances; These are the risk assessment coefficients for the left and right sides, respectively. To prevent a vehicle from being rear-ended after engaging active avoidance mode, the following conditions are established to allow time for the following vehicle to stop and give way:
[0014] In the formula, and These are the vehicle's heading angle relative to the post-collision angle required for the vehicle to avoid a collision to the left or right; This refers to the safety margin factor. when When, the vehicle actively swerves to the left to give way; when At that time, the vehicle actively swerved to the right to avoid it.
[0015] As a preferred solution, if the condition of allowing time for following vehicles to stop and yield is not met, a restricted avoidance mode is executed, specifically including: Calculate lateral displacement and front wheel steering angle :
[0016]
[0017] In the formula, The width of the vehicle itself; R is the distance from the side of the vehicle that is avoiding the obstacle to the side of the vehicle in front; R is the required turning radius, and x is the longitudinal distance of the vehicle system during the avoidance process; t is the vehicle's wheelbase; v is the vehicle's longitudinal speed; t is the preset avoidance time. Based on the actual yaw rate of the vehicle measured by the sensor and the desired yaw rate of the vehicle, the required additional yaw torque is obtained using PID control. The driving torque of the left and right wheels is distributed with the objective function of minimizing the tire load rate, combined with the constraints. The system monitors the status of the drive system in real time. If the entire drive system fails, it enters the attitude fine-tuning mode.
[0018] As a preferred option, when executing the attitude fine-tuning mode, the specific steps include: To check the working status of the vehicle's steering and braking systems; Combined with the impact force from the rear vehicle, controlled yaw motion or passive protective operation is performed to move the vehicle away from the danger zone.
[0019] As a preferred embodiment, the controlled yaw motion or passive protective operation combined with the impact thrust of the rear vehicle specifically includes: If the steering system is functioning normally, in the event of an unavoidable secondary collision, the impact force from the following vehicle, combined with a preset posture and differential braking, will generate a controlled yaw motion, resulting in a wheel rotation angle of [missing information]. In the formula, It is a symbolic function; The angle between the main threat direction and the vehicle's longitudinal axis is defined as positive on the left and negative on the right. This is the maximum steering angle that can still be safely executed under the current system conditions; If the braking system is available, different braking forces are applied to the four wheels to generate auxiliary yaw moments. The yaw moments generated by differential braking are: In the formula, , , , These represent the braking forces of the left front, right front, left rear, and right rear wheels, respectively, with l being the wheelbase. The braking force distribution rules are as follows: like If the vehicle is turning left, then a positive yaw moment is expected to be generated to assist the vehicle in completing the turn. ; like At this point, the vehicle is turning right, requiring a negative yaw moment to assist in the turn. Therefore, we have... ; The impact force from the rear vehicle can be decomposed into:
[0020] In the formula, The impact force of the following vehicle; The longitudinal force generated by the impact propels the vehicle forward. With steering angle The combined effect caused the vehicle to move laterally; The angle between the collision force and the vehicle's longitudinal axis; Calculate the total yaw moment:
[0021] In the formula, d is the longitudinal distance from the point of impact force application to the vehicle's center of gravity; By controlling the different braking torques of the four wheels, the vehicle can track the desired yaw rate output by the two-degree-of-freedom vehicle model. If the vehicle's steering system is unavailable but the braking system is available, braking will be initiated based on the predicted point of impact, and all occupants will have their seatbelts pre-tensioned and the multi-stage airbags will be deployed. If the vehicle's steering and braking systems are both unavailable, active intervention will be abandoned, and only the pretensioning of seat belts for all occupants and adjustment of multi-stage airbag deployment will be performed.
[0022] The present invention also proposes an electronic device, which includes a processor and a memory storing computer program instructions; the processor implements the above-described control method when executing the computer program instructions.
[0023] Compared with the prior art, the present invention has at least the following beneficial effects: (1) The active steering control system for vehicle secondary collision avoidance of the present invention transforms the vehicle collision passive safety to active avoidance, directly reducing the harm of chain rear-end collision accidents.
[0024] (2) The present invention evaluates the vehicle posture, power system, steering system, sensor status and environmental conditions in real time, and intelligently enters three different avoidance modes to maximize the safety of the driver and passengers.
[0025] (3) This invention ensures that the vehicle can take secondary avoidance after the rear-end collision stops. The system not only considers the vehicle's own status, but also needs to assess the surrounding traffic environment, such as road and traffic flow information, through radar and / or camera. The quantitative assessment is used to select the path with the lowest risk and the most space to successfully complete the avoidance. Attached Figure Description
[0026] Figure 1 This is a schematic diagram illustrating the execution of the secondary collision avoidance control system of the present invention.
[0027] Figure 2 This is the execution flowchart of Mode 1 (i.e., the active avoidance mode) in the embodiment.
[0028] Figure 3 This is the execution flowchart of Mode 2 (i.e., restricted avoidance mode) in the embodiment.
[0029] Figure 4 This is the execution flowchart of Mode 3 (i.e., attitude fine-tuning mode) in the embodiment.
[0030] Figure 5 This is a diagram showing the forces acting on each wheel during secondary collision avoidance control. Detailed Implementation
[0031] In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention can be practiced without one or more of these details. In other instances, certain technical features well-known in the art have not been described in order to avoid obscuring the invention.
[0032] This embodiment discloses a secondary collision avoidance control system for a hub motor-driven vehicle, see [link to documentation]. Figure 1 As shown. For in-wheel motor-driven automobiles, where the in-wheel motor is directly installed inside or near the drive wheel, it features a simple structure, short transmission path, and high transmission efficiency. Since the drive motors can be controlled independently, additional yaw torque can be generated by utilizing the different driving torques output by the left and right motors, enabling the vehicle to steer.
[0033] In this embodiment, the secondary collision avoidance control system consists of four parts: a collision detection sensor, an environmental perception sensor, a vehicle status sensor, and a control module.
[0034] The collision detection sensors include airbag collision sensors and acceleration sensors, used to determine that the first rear-end collision has occurred.
[0035] The environmental perception sensor includes a rear radar and / or camera and left and right side radars and / or cameras, used to acquire surrounding traffic environment information, including road information, traffic flow information, the distance between the following vehicle and the current vehicle, and the avoidance distance to the left and right.
[0036] The vehicle status sensor includes an inertial measurement unit, wheel speed sensors, and steering wheel angle sensors, used to acquire vehicle status information including vehicle attitude, vehicle angle, wheel speed, yaw rate, and longitudinal speed.
[0037] The control module receives output signals from the collision detection sensor, environmental perception sensor, and vehicle status sensor, and selects the corresponding avoidance mode based on the vehicle's current damage status and surrounding traffic environment information. The avoidance modes include active avoidance mode, restricted avoidance mode, and attitude fine-tuning mode.
[0038] Specifically, the vehicle uses sensors such as airbag collision and vehicle acceleration to determine whether it has rear-ended the vehicle in front; if so, it immediately activates the secondary collision avoidance process.
[0039] When the vehicle first rear-ends the vehicle in front, the active steering control system for secondary collision avoidance is immediately activated, and selects from mode one to mode three in the avoidance system based on the current damage status of the vehicle and road information.
[0040] When the vehicle is fully functional or slightly damaged, select Mode 1, the active avoidance mode. In this mode, the vehicle's attitude is stable, and the power steering system and sensors can support the vehicle in actively avoiding obstacles.
[0041] When a vehicle is moderately damaged, such as when its power system or steering system is damaged or its attitude is unstable, making it unable to perform active avoidance behavior, mode two, namely limited avoidance mode, is adopted.
[0042] When a vehicle is severely damaged, with most of its power and steering systems failing or sensor data lost, rendering it unable to take evasive action, mode three, namely attitude fine-tuning mode, is adopted.
[0043] After a vehicle rear-ends another vehicle, the active steering control system for secondary collision avoidance is activated. It promptly assesses the vehicle's current state and selects different modes based on the assessed risk level to achieve the function of secondary collision avoidance.
[0044] Specifically, it determines whether the current vehicle turning angle matches the desired turning angle. If they do not match, the steer-by-wire system fails, and redundant control is activated to achieve vehicle steering. The vehicle turning angle is obtained based on sensors installed on the vehicle.
[0045] Furthermore, once the vehicle's secondary obstacle avoidance system is activated, it immediately performs a self-check of the power and steering sensors. Depending on the degree of damage to the vehicle, it enters different modes. The self-check is based on feedback signals from each actuator. When the vehicle's power system, steering system, and sensors are mostly functioning normally, the system can perform comprehensive active steering avoidance, entering Mode 1. When the vehicle's power system or steering system is partially damaged (e.g., reduced output power, delayed steering response), or sensor data may be incomplete, it enters Mode 2. When the vehicle is severely damaged, and the power and steering systems may largely fail (e.g., steering jamming, insufficient power), or sensor values have not been updated for more than four operating cycles, it enters Mode 3.
[0046] Furthermore, when entering Mode 1, the first step is to assess the risk level of being rear-ended by a vehicle from behind: Chain-reaction rear-end collision risk assessment :
[0047] In the formula, L is the speed of the following vehicle, and L is the distance between the following vehicle and the current vehicle. For the acceleration of the following vehicle, This is the maximum acceleration that the current road surface can provide.
[0048] Avoidance space risk assessment:
[0049] In the formula, The speeds of traffic on the left and right sides are respectively. These are the predicted avoidable distances.
[0050] To prevent a vehicle from being rear-ended after it has voluntarily yielded, time is allowed for the following vehicle to stop and yield. The following conditions are established:
[0051] In the formula, and These are the vehicle's heading angle relative to the post-collision position required for the vehicle to swerve to the left or right. This is the safety margin factor, and its value is greater than 1.
[0052] when At that time, the vehicle actively swerved to the left to give way. At that time, the vehicle actively swerved to the right to avoid it.
[0053] If formula (3) is not satisfied, it means that the vehicle has no possibility of actively avoiding the obstacle and enters the subsequent modes two and three.
[0054] Lateral displacement calculation:
[0055] The idea is that moving a vehicle from behind to the side of the vehicle in front can prevent a chain-reaction rear-end collision. In the formula, For the width of the vehicle itself, It is the distance from the side of the vehicle that is avoiding the collision to the side of the vehicle in front.
[0056] Turning angle calculation: To achieve lateral displacement The vehicle needs to turn, and because the vehicle speed is very low, its path is approximately a sine function or a circular arc. This invention uses a circular arc model for simplification.
[0057] In the formula, R is the required turning radius, and x is the longitudinal distance of the system during the vehicle's avoidance process.
[0058] Furthermore, the required front wheel steering angle of the vehicle can be calculated:
[0059] In the formula, For the required front wheel steering angle, Let v be the vehicle's wheelbase, v be the vehicle's longitudinal speed, and t be the preset avoidance time, which determines the aggressiveness of the avoidance maneuver. Since the avoidance time is relatively short, the longitudinal speed can be assumed to be uniformly accelerating; therefore, the longitudinal displacement is approximately... If the preset time is short, the required front wheel steering angle... If the value exceeds the limit, differential drive must be used to add additional yaw moment to complete the avoidance. The specific calculation method is as follows:
[0060] In the formula, This is the vehicle's actual yaw rate at this moment, which can be measured by a sensor; This is the desired yaw rate of the vehicle, which can be obtained from a two-degree-of-freedom vehicle model.
[0061] The total additional yaw moment required can be obtained using PID control:
[0062] In the formula, This is the required additional yaw moment. , and The gain of the PID controller needs to be calibrated according to the vehicle model.
[0063] according to Figure 4 We can conclude that:
[0064] Finally, using the lowest tire load rate as the objective function, the driving torque of the left and right wheels is obtained according to the constraints.
[0065] Objective function:
[0066] If the steering system or drive system fails to function at this time, switch to mode two; if all four wheel hub motors fail to function at this time, switch to mode three.
[0067] Furthermore, when the secondary obstacle avoidance system enters mode two, it utilizes the residual capacity of the actuator to complete obstacle avoidance. At this time, the vehicle state still satisfies equation (9). Due to the partial failure of the four drive wheels, the yaw moment formula in equation (9) is modified as follows:
[0068] at this time, , which is the ratio of the actual output torque of the drive motor to the expected output torque.
[0069] Finally, taking the lowest tire load rate as the objective function of equation (10), the driving torque of the left and right wheels is obtained according to the constraints.
[0070] If the entire drive system malfunctions at this time, the vehicle's steering and other functions will be unable to perform active obstacle avoidance, and the vehicle will enter mode three, the forced obstacle avoidance mode.
[0071] Upon entering Mode 3, if the vehicle's steering system is functioning normally, in the event of an unavoidable secondary collision, the impact force from the following vehicle, combined with a preset posture and differential braking, generates a controlled yaw motion, "pushing" the vehicle out of the danger zone. At this point, the vehicle's wheel angle is:
[0072] In the formula, For symbolic functions, The angle between the main threat direction and the vehicle's longitudinal axis is defined as positive on the left and negative on the right. This is the maximum steering angle that can be safely executed under the current system conditions. It should be noted that this value may be lower than the normal value.
[0073] Furthermore, to amplify the above effect, when the vehicle's braking system is available, different braking forces need to be applied to the four wheels to generate an auxiliary yaw moment. The yaw moment generated by differential braking is:
[0074] In the formula, These are the braking forces for the front left, front right, rear left, and rear right wheels, respectively. This refers to the wheel track.
[0075] To amplify the steering decision in formula (11), the braking force distribution should follow: like If the vehicle is turning left, then a positive yaw moment is expected to be generated to assist the vehicle in completing the turn. ,like At this point, the vehicle is turning right, requiring a negative yaw moment to assist in the turn. .
[0076] When the vehicle is in a preset position When the differential braking force is hit by a vehicle behind, its movement is the result of the combined action of the collision thrust and the active control torque.
[0077] The impact thrust can be decomposed into:
[0078] In the formula, For the impact force of the rear vehicle, The longitudinal force generated by the impact propels the vehicle forward. With steering angle The combined effect caused the vehicle to move laterally. The angle between the collision force and the vehicle's longitudinal axis.
[0079] The final total yaw moment is obtained as follows:
[0080] In the formula, d is the longitudinal distance from the point of impact force application to the vehicle's center of gravity.
[0081] Finally, By tracking the desired yaw rate output from a two-degree-of-freedom vehicle model and controlling different braking torques on the four wheels, the desired yaw rate can be obtained. This allows a vehicle to transition from a passive, impact-stricken state to a controlled, ejected or spun-out state, thereby escaping the most dangerous impact core and minimizing damage.
[0082] It should be noted that the control method disclosed in the above embodiments can be written into the vehicle's ECU (Electronic Control Unit). The ECU includes a processor, a memory, a communication interface, and a communication bus. The processor, memory, and communication interface communicate with each other through the communication bus. The memory stores at least one executable instruction, which causes the processor to execute the vehicle energy-saving and stability coordination control method disclosed in the above embodiments. It should be understood that other hardware and / or software modules can be used in conjunction with electronic devices, including but not limited to: microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, and data backup storage systems.
[0083] Embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROMs) containing computer-usable program code. The form of a computer program product implemented on ROM, optical memory, etc.
[0084] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.
[0085] Memory may include non-persistent memory in computer-readable media, random access memory, and / or non-volatile memory, such as read-only memory or flash memory. Memory is an example of computer-readable media.
[0086] Computer-readable media include both permanent and non-permanent, removable and non-removable media that can store information by any method or technology. Information can be computer-readable instructions, data structures, program modules, or other data. Examples of computer storage media include, but are not limited to, phase-change memory, static random access memory, dynamic random access memory, other types of random access memory, read-only memory, electrically erasable programmable read-only memory, flash memory or other memory technologies, optical disc read-only memory, digital versatile optical disc or other optical storage, magnetic tape, magnetic magnetic disk storage or other magnetic storage devices, or any other non-transfer medium that can be used to store information accessible by a computing device. As defined herein, computer-readable media do not include temporary computer-readable media, such as modulated data signals and carrier waves.
[0087] As described above, although the invention has been shown and described with reference to specific preferred embodiments, it should not be construed as limiting the invention itself. Various changes in form and detail may be made without departing from the spirit and scope of the invention as defined in the appended claims.
Claims
1. A secondary collision avoidance control system for a hub motor-driven vehicle, characterized in that, This includes collision detection sensors, environmental perception sensors, vehicle status sensors, and control modules; The collision detection sensors include an airbag collision sensor and an acceleration sensor, used to determine that the first rear-end collision has occurred. The environmental perception sensor includes a rear radar and / or camera, and left and right side radars and / or cameras, used to acquire surrounding traffic environment information including road information, traffic flow information, the distance between the following vehicle and the current vehicle, and the avoidance distance on the left and right sides. The vehicle status sensor includes an inertial measurement unit, a wheel speed sensor, and a steering wheel angle sensor, used to acquire vehicle status information including vehicle attitude, vehicle angle, wheel speed, yaw rate, and longitudinal speed. The control module is used to receive output signals from the collision detection sensor, the environmental perception sensor and the vehicle status sensor, and select the corresponding avoidance mode according to the current damage status of the vehicle and the surrounding traffic environment information. The avoidance modes include active avoidance mode, restricted avoidance mode and attitude fine-tuning mode.
2. A secondary collision avoidance control method for a hub motor-driven vehicle, implemented based on the secondary collision avoidance control system for a hub motor-driven vehicle as described in claim 1, characterized in that, Includes the following steps: The collision detection sensor detects whether a first rear-end collision has occurred. If so, the secondary collision avoidance control system is immediately activated. The powertrain, steering system, and sensors are self-checked using vehicle status sensors and feedback signals from various actuators to assess the current damage status of the vehicle. Select the appropriate avoidance mode based on the current damage status of the vehicle: If the vehicle's powertrain and steering systems are functioning normally, and the system is deemed capable of performing comprehensive active steering avoidance, then it enters active avoidance mode. If the vehicle's powertrain or steering system is partially damaged, it will enter a restricted avoidance mode; such partial damage includes reduced output power and delayed steering response. If the vehicle's powertrain or steering system partially fails, it will enter a fine-tuning mode; such partial failures include steering jamming and insufficient power. Perform the corresponding avoidance operation for the selected avoidance mode to complete the secondary collision avoidance.
3. The secondary collision avoidance control method for a hub motor-driven vehicle according to claim 2, characterized in that, The assessment of the vehicle's current damage status includes: determining whether the vehicle's turning angle is consistent with the vehicle's expected turning angle; if not, determining that the steer-by-wire system has failed and activating redundant control to achieve vehicle steering.
4. The secondary collision avoidance control method for a hub motor-driven vehicle according to claim 2, characterized in that, In the active avoidance mode, when distributing the driving torque of the left and right wheels with the objective function of minimizing the tire load rate, the vehicle dynamics constraints must be met.
5. The secondary collision avoidance control method for a hub motor-driven vehicle according to claim 2, characterized in that, In the restricted avoidance mode, when distributing the driving torque of the left and right wheels with the objective function of minimizing the tire load rate, the vehicle dynamics constraints and the output torque limit of the drive motor must be met.
6. The secondary collision avoidance control method for a hub motor-driven vehicle according to claim 2, characterized in that, When executing the proactive avoidance mode, the specific steps include: Risk assessment is conducted based on surrounding traffic environment information, including a chain-reaction rear-end collision risk assessment. and avoidance space risk assessment , : In the formula, L is the speed of the following vehicle; L is the distance between the following vehicle and the current vehicle. This refers to the acceleration of the following vehicle; The maximum acceleration that the current road surface can provide; These represent the traffic speeds on the left and right sides, respectively. These are the predicted avoidable distances; These are the risk assessment coefficients for the left and right sides, respectively. To prevent a vehicle from being rear-ended after engaging active avoidance mode, the following conditions are established to allow time for the following vehicle to stop and give way: In the formula, and These are the vehicle's heading angle relative to the post-collision angle required for the vehicle to avoid a collision to the left or right; This refers to the safety margin factor. when When, the vehicle actively swerves to the left to give way; when At that time, the vehicle actively swerved to the right to avoid it.
7. The secondary collision avoidance control method for a hub motor-driven vehicle according to claim 6, characterized in that, If the condition of allowing time for following vehicles to stop and yield is not met, a restricted avoidance mode will be executed, which specifically includes: Calculate lateral displacement and front wheel steering angle : In the formula, The width of the vehicle itself; R is the distance from the side of the vehicle that is avoiding the obstacle to the side of the vehicle in front; R is the required turning radius, and x is the longitudinal distance of the vehicle system during the avoidance process; t is the vehicle's wheelbase; v is the vehicle's longitudinal speed; t is the preset avoidance time. Based on the actual yaw rate of the vehicle measured by the sensor and the desired yaw rate of the vehicle, the required additional yaw torque is obtained using PID control. The driving torque of the left and right wheels is distributed with the objective function of minimizing the tire load rate, combined with the constraints. The system monitors the status of the drive system in real time. If the entire drive system fails, it enters the attitude fine-tuning mode.
8. The secondary collision avoidance control method for a hub motor-driven vehicle according to claim 2, characterized in that, When executing the attitude fine-tuning mode, the specific steps include: To check the working status of the vehicle's steering and braking systems; Combined with the impact force from the rear vehicle, controlled yaw motion or passive protective operation is performed to move the vehicle away from the danger zone.
9. The secondary collision avoidance control method for a hub motor-driven vehicle according to claim 8, characterized in that, The controlled yaw motion or passive protective operation implemented in conjunction with the impact thrust of the rear vehicle specifically includes: If the steering system is functioning normally, in the event of an unavoidable secondary collision, the impact force from the following vehicle, combined with a preset posture and differential braking, will generate a controlled yaw motion, resulting in a wheel rotation angle of [missing information]. In the formula, It is a symbolic function; The angle between the main threat direction and the vehicle's longitudinal axis is defined as positive on the left and negative on the right. This is the maximum steering angle that can still be safely executed under the current system conditions; If the braking system is available, different braking forces are applied to the four wheels to generate auxiliary yaw moments. The yaw moments generated by differential braking are: In the formula, , , , These represent the braking forces of the left front, right front, left rear, and right rear wheels, respectively, with l being the wheelbase. The braking force distribution rules are as follows: like If the vehicle is turning left, then a positive yaw moment is expected to be generated to assist the vehicle in completing the turn. ; like At this point, the vehicle is turning right, requiring a negative yaw moment to assist in the turn. Therefore, we have... ; The impact force from the rear vehicle can be decomposed into: In the formula, The impact force of the following vehicle; The longitudinal force generated by the impact propels the vehicle forward. With steering angle The combined effect caused the vehicle to move laterally; The angle between the collision force and the vehicle's longitudinal axis; Calculate the total yaw moment: In the formula, d is the longitudinal distance from the point of impact force application to the vehicle's center of gravity; By controlling the different braking torques of the four wheels, the vehicle can track the desired yaw rate output by the two-degree-of-freedom vehicle model. If the vehicle's steering system is unavailable but the braking system is available, braking will be initiated based on the predicted point of impact, and all occupants will have their seatbelts pre-tensioned and the multi-stage airbags will be deployed. If the vehicle's steering and braking systems are both unavailable, active intervention will be abandoned, and only the pretensioning of seat belts for all occupants and adjustment of multi-stage airbag deployment will be performed.
10. An electronic device, characterized in that, include: Processor and memory storing computer program instructions; When the processor executes the computer program instructions, it implements the control method as described in any one of claims 2 to 9.