Driving assistance system and torque distribution ratio adjustment device thereof

Abstract

The present invention relates to a torque distribution ratio adjustment device (1) for adjusting the torque distribution ratio between the front axle and the rear axle of a split-axle four-wheel drive vehicle, wherein the torque distribution ratio adjustment device (1) is communicatively connected to a detection device for detecting a vehicle state and is configured to: determine the current steering intention of the driver based on a detection signal from the detection device, and then determine an adjustment scheme for the torque distribution ratio based on the determined current steering intention. The present invention also relates to a method for adjusting the torque distribution ratio between the front axle and the rear axle of a split-axle four-wheel drive vehicle implemented by the torque distribution ratio adjustment device (1) and a driving assistance system including the torque distribution ratio adjustment device (1).

Description

Technical Field

[0001] The present invention relates to a torque distribution ratio adjustment device for a vehicle and an operating method thereof. In addition, the present invention also relates to a driving assistance system comprising the torque distribution ratio adjustment device. Background Art

[0002] New energy split-axle four-wheel drive vehicles with independent powertrains on the front and rear axles of the vehicle are increasingly being developed and marketed. New energy split-axle four-wheel drive vehicles mainly include pure electric split-axle four-wheel drive vehicles and hybrid split-axle four-wheel drive vehicles. In pure electric split-axle four-wheel drive vehicles, the front and rear axles of the vehicle are each equipped with a drive motor as a power source. In hybrid split-axle four-wheel drive vehicles, the rear axle of the vehicle is usually equipped with a drive motor as a power source, while the power source of the front axle of the vehicle is an engine or a combination of an engine and a motor.

[0003] In particular, nowadays, more and more new energy split-axle four-wheel drive vehicles are equipped with the so-called traction control system (TCS), in which the traction control system prevents wheel slip or vehicle tail-spinning by adjusting the valve opening or controlling the brakes to ensure that the vehicle still has good performance and sufficient safety under bad road conditions.

[0004] We are still looking forward to improving the performance of new energy split-axle four-wheel drive vehicles. Summary of the invention

[0005] The object of the present invention is to provide a torque distribution ratio adjustment device for a vehicle and an operating method thereof, as well as a corresponding driving assistance system.

[0006] According to one aspect of the present invention, the above-mentioned purpose is achieved through a torque distribution ratio adjustment device for adjusting the torque distribution ratio between the front axle and the rear axle of a new energy split-axle four-wheel drive vehicle, wherein the torque distribution ratio adjustment device is communicatively connected to a detection device for detecting the vehicle state and is configured to: determine the driver's current steering intention based on the detection signal from the detection device, and then determine the adjustment plan of the torque distribution ratio based on the determined current steering intention.

[0007] According to a preferred embodiment of the present invention, the torque distribution ratio adjustment device is configured to determine the current steering intention in the following manner: determine the driver's current steering operation and the current vehicle steering trend based on the detection signal and then determine the current steering intention based on the determined current steering operation and the current vehicle steering trend.

[0008] According to a preferred embodiment of the present invention, the torque distribution ratio adjustment device is configured as follows: if the current steering intention determined is that the current steering operation is aggravating the current vehicle steering trend, an adjustment plan is made to reduce the front axle torque distribution ratio and increase the rear axle torque distribution ratio; if the current steering intention determined is that the current steering operation is counteracting the current vehicle steering trend, an adjustment plan is made to increase the front axle torque distribution ratio and reduce the rear axle torque distribution ratio.

[0009] According to a preferred embodiment of the present invention, the current steering operation is described from two dimensions: the current steering wheel angle position and the current steering direction, wherein the current steering direction includes a first reverse direction for rotating the steering wheel toward a return position and a second direction opposite to the first direction for rotating the steering wheel away from the return position.

[0010] According to a preferred embodiment of the present invention, the torque distribution ratio adjustment device is configured as follows:

[0011] - when it is determined that the driver is steering in the first direction when the current steering wheel angle position is in the same direction as the current vehicle steering trend, it is determined that the current steering operation is against the current vehicle steering trend; and / or

[0012] - when it is determined that the driver is steering in the second direction when the current steering wheel angle position is in the same direction as the current vehicle steering trend, it is determined that the current steering operation is exacerbating the current vehicle steering trend; and / or

[0013] - when it is determined that the driver is steering in the first direction when the current steering wheel angle position is in a direction different from the current vehicle steering trend, it is determined that the current steering operation is exacerbating the current vehicle steering trend; and / or

[0014] -When it is determined that the driver is steering the wheel in the second direction when the current steering wheel angle position is in a direction different from the current vehicle steering trend, it is determined that the current steering operation is against the current vehicle steering trend.

[0015] According to another aspect of the present invention, the above purpose is also achieved by a method for adjusting the torque distribution ratio between the front axle and the rear axle of a new energy split-axle four-wheel drive vehicle, which is implemented by the torque distribution ratio adjustment device according to the present invention.

[0016] According to yet another aspect of the present invention, the above object is also achieved by a driving assistance system for assisting a driver's operation, the driving assistance system comprising the above torque distribution ratio adjustment device and a switch for activating the torque distribution ratio adjustment device.

[0017] According to a preferred embodiment of the present invention, the driving assistance system is configured to suspend or terminate the adjustment of the torque distribution ratio by the torque distribution ratio adjustment device once it is detected that the accelerator is released or the brake pedal is depressed. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] More features and advantages of the present invention can be further described by the following detailed description of specific embodiments with reference to the accompanying drawings. The accompanying drawings are:

[0019] Figure 1 A structural block diagram of a torque distribution ratio adjustment device 1 according to the present invention is shown;

[0020] Figure 2 A flowchart showing a method for adjusting a torque distribution ratio according to the present invention; and

[0021] Figure 3 A flow chart illustrating an exemplary method for determining a driver's current steering intent. DETAILED DESCRIPTION

[0022] Figure 1 The structural block diagram of the torque distribution ratio adjustment device 1 according to the present invention is shown. The torque distribution ratio adjustment device 1 is configured to adjust the torque distribution ratio between the front axle and the rear axle of a new energy split-axle four-wheel drive vehicle.

[0023] like Figure 1 As shown, the torque distribution ratio adjustment device 1 is communicatively connected with the detection devices 5 and 6 for detecting the vehicle status and is configured to: determine the driver's current steering intention based on the detection signals from the detection devices 5 and 6, and then determine the torque distribution ratio adjustment plan based on the determined current steering intention.

[0024] According to a preferred embodiment, the torque distribution ratio adjustment device 1 is configured to include a judgment unit 2 and a decision unit 3 in communication with the judgment unit 2. The judgment unit 2 is configured to determine the driver's current steering intention based on the received detection signal and transmit the determination result to the decision unit 3. Then, the decision unit 3 determines a specific torque distribution ratio adjustment scheme based on the received determination result and then provides the determined adjustment scheme to the execution device 4. Then, the execution device 4 executes the adjustment of the torque distribution ratio of the front and rear axles.

[0025] Preferably, the torque distribution ratio adjustment device 1 can send a request signal including a torque distribution ratio adjustment scheme to the vehicle central controller, and then the vehicle central controller outputs an actuation instruction to relevant components.

[0026] Further, the torque distribution ratio adjustment device 1, preferably the judgment unit 2, identifies the driver's current wheel turning operation and the current vehicle steering trend based on the detection signal and then determines the current steering intention based on the identified current wheel turning operation and the current vehicle steering trend, specifically determining whether the driver's current wheel turning operation is aggravating the current vehicle steering trend or counteracting the current vehicle steering trend. If it is identified that the driver's current wheel turning operation is aggravating the current vehicle steering trend, it means that the current steering trend of the vehicle may be lower than the steering trend expected by the driver. In this case, the decision unit 3 makes an adjustment plan to reduce the front axle torque quota and increase the rear axle torque quota. Conversely, if it is identified that the driver's current wheel turning operation is counteracting the current vehicle steering trend, it means that the current steering trend of the vehicle may exceed the steering trend expected by the driver. In this case, the decision unit 3 makes an adjustment plan to increase the front axle torque quota and reduce the rear axle torque quota.

[0027] Since the front and rear axles of new energy split-axle four-wheel drive vehicles are equipped with independent powertrains, it is possible to increase or decrease torque on the front and rear axles separately, and the torque increase rate of the motor is faster than that of a fuel four-wheel drive vehicle.

[0028] The following specifically explains a method for identifying the basis for determining the driver's current steering intention, namely, the driver's current steering operation and the current vehicle steering trend.

[0029] According to the present invention, the current steering operation of the driver is described from two dimensions: the current steering direction of the driver and the current steering wheel angle position SAS. That is, the physical object of the steering operation is represented by the combination of two specific measurable parameters, the steering direction and the steering wheel angle position SAS, and the latter is known by measuring the former two. Specifically, the combination of the current steering direction and the current steering wheel angle position SAS can describe which direction the driver is performing the steering operation for which steering wheel angle position.

[0030] Further, within the scope of the present invention, the steering direction is divided into two types. The first steering direction is the direction in which the steering wheel is turned toward the return position (the steering operation in this direction is also referred to as "returning"), which includes returning to the center from the left and returning to the center from the right. The second steering direction is the steering direction opposite to the first steering direction, that is, the direction in which the steering wheel is turned away from the return position, which includes deviating to the left and deviating to the right.

[0031] In order to detect the driver's steering direction and steering wheel angle position SAS, such as Figure 1As shown, a steering wheel angle sensor 5 is provided and is in communication connection with the torque distribution ratio adjustment device 1. With the help of the steering wheel angle sensor 5, the steering wheel angle position SAS can be measured and the steering direction can be determined.

[0032] It should be noted here that, in this article, the parameter "steering wheel angle position SAS" should be understood as a vector representing the angular position of the steering wheel, wherein the zero value point of the vector represents that the steering wheel is in the return position, and the sign and absolute value of the vector respectively represent the direction and degree of deviation of the steering wheel from the return position.

[0033] Furthermore, the steering wheel angle sensor 5 monitors the steering wheel angle position SAS in real time, for example, collecting the steering wheel angle position SAS at fixed time intervals. and Respectively represent the time point T k and time point T k+1 The steering wheel angle position measured at . Therefore, the change in the steering wheel angle position SAS can be calculated using the following formula (1):

[0034]

[0035] in, and Respectively represent the steering wheel angle position and The absolute value of .

[0036] If calculated If it is a negative value, it means that T k+1 The steering direction at this time point is the first steering direction mentioned above, which means that the steering operation of the driver at this time point is turning the steering wheel in the return direction. If it is a positive value, it means T k+1 The steering direction at this time point is the second steering direction mentioned above, which means that the steering operation of the driver at this time point is turning the steering wheel in the opposite direction to the return direction.

[0037] In addition, the data collection time interval of the steering wheel angle sensor 5 should be set to be short so as to track the driver's real-time steering intention with high time resolution, thereby ensuring the timeliness and accuracy of the auxiliary operation implemented by the torque distribution ratio adjustment device 1. Preferably, the data collection time interval is set to 20 seconds.

[0038] As for the other basis for determining the current steering intention of the driver, the current vehicle steering tendency, according to the present invention, it is characterized as the direction of the vehicle's lateral acceleration. That is, the physical object of the vehicle's steering tendency is represented by the specific measurable parameter of the direction of the vehicle's lateral acceleration, and the latter is known by measuring the former. For this purpose, Figure 1 As shown, a lateral acceleration sensor 6 is provided and is connected to the torque distribution ratio adjustment device 1. By means of the lateral acceleration sensor 6, the vehicle lateral acceleration a can be measured. y The direction of the vehicle's lateral acceleration is thus measured.

[0039] It should be noted that, in this article, although the steering wheel angle position SAS and the vehicle lateral acceleration a are not specifically limited y The positive and negative of these two vectors correspond to the spatial direction, but the two vectors should advantageously have a uniform correspondence. That is, if the steering wheel angle position SAS is positive when it is to the left and negative when it is to the right, then the vehicle lateral acceleration a y Conversely, if the steering wheel angle position SAS is positive when it is to the right and negative when it is to the left, then the vehicle lateral acceleration a y Therefore, if the steering wheel angle position SAS and the vehicle lateral acceleration a y The measured values ​​of have the same positive and negative signs (i.e., both are positive or negative), which means that the steering wheel angle position represented by the steering wheel angle position SAS and the vehicle lateral acceleration a y The vehicle steering trends represented by are in the same direction. On the contrary, if the steering wheel angle position SAS and the vehicle lateral acceleration a y If the measured values ​​have opposite signs (i.e., one is positive and the other is negative), it means that the steering wheel angle position and the vehicle steering tendency are opposite.

[0040] It should be noted here that the terms "positive", "negative", "positive value" and "negative value" involved in this article do not include zero value.

[0041] Figure 2 A flow chart of a method for adjusting a torque distribution ratio according to the present invention is shown.

[0042] like Figure 2As shown, first, in step S1-1, the current steering wheel angle position and the current steering direction are obtained based on the measurement signal of the steering wheel angle sensor 5 and the current steering operation is determined accordingly, and in step S1-2, the current vehicle steering trend is determined based on the measurement signal of the lateral acceleration sensor 6, as described above for details. Further, in step S2, the driver's current steering intention is judged based on the determined current steering operation and the current vehicle steering trend, that is, it is determined whether the driver's current steering operation is aggravating or counteracting the current vehicle steering trend. If it is determined that the current steering operation is aggravating the current vehicle steering trend, then in step S3, an adjustment plan is made to reduce the front axle torque distribution ratio and increase the rear axle torque distribution ratio; conversely, if it is determined in step S2 that the current steering operation is counteracting the current vehicle steering trend, then in step S4, an adjustment plan is made to increase the front axle torque distribution ratio and reduce the rear axle torque distribution ratio. Then, the adjustment plan is executed in step S5.

[0043] In particular, the adjustment of the torque distribution ratio of the front and rear axles can be made when the total torque remains unchanged or changes. According to a preferred embodiment, the adjustment scheme made in step S3 is to reduce the front axle torque and / or increase the rear axle torque, and the adjustment scheme made in step S4 is to increase the front axle torque and / or reduce the rear axle torque.

[0044] Figure 3 A flowchart of an exemplary method for determining the driver's current steering intention is shown. Figure 3 As shown, firstly, in step S11, the current steering wheel angle position is measured by means of the steering wheel angle sensor 5 and the current vehicle turning tendency is determined by means of the lateral acceleration sensor 6. Then, in step S12, the direction of the current steering wheel angle position and the direction of the current vehicle turning tendency are compared. If it is determined that the two are in different directions, that is, opposite directions to each other, the process proceeds to step S13; if they are in the same direction, the process proceeds to step S14.

[0045] Preferably, by comparing the positive and negative values ​​of the measured value of the current steering wheel angle position SAS with the current vehicle lateral acceleration a y The comparison in step S12 is performed based on the positive and negative values ​​of the two measured values. If the two measured values ​​are one positive and one negative, it is determined that the direction of the current steering wheel angle position and the direction of the current vehicle turning trend are in opposite directions; conversely, if the two measured values ​​are both positive or both negative, it is determined that the direction of the current steering wheel angle position and the direction of the current vehicle turning trend are in the same direction.

[0046] Then, the current steering direction is determined in step S13. If it is determined in step S13 that the current steering direction is the first steering direction, i.e., the return direction, then in step S15, it is concluded that the driver's current steering intention is to aggravate the current vehicle steering trend, and then in step S17, an adjustment plan is made to reduce the front axle torque distribution ratio and increase the rear axle torque distribution ratio; if it is determined in step S13 that the current steering direction is the second direction, then in step S16, it is concluded that the driver's current steering intention is to resist the current vehicle steering trend, and then in step S18, an adjustment plan is made to increase the front axle torque distribution ratio and reduce the rear axle torque distribution ratio.

[0047] On the other hand, the determination of the current steering direction is also implemented in step S14. If it is determined that the current steering direction is the second direction, then in step S15, it is concluded that the driver's current steering intention is to aggravate the current vehicle steering trend and then the above step S17 is executed; if it is determined that the current steering direction is the first steering direction in step S14, then in step S16, it is concluded that the driver's current steering intention is to resist the current vehicle steering trend and then the above step S18 is executed.

[0048] According to the present invention, preferably, the torque distribution ratio adjustment device 1 is also communicatively connected to a wheel speed sensor, a yaw rate sensor, a vehicle longitudinal acceleration sensor, an axle torque sensor, a sensor for detecting the position of a brake pedal, a sensor for detecting the position of an accelerator pedal, etc., not shown, so as to obtain a variety of measurement values ​​reflecting the vehicle state, thereby being able to evaluate the vehicle's driving state in real time. If the evaluation result shows that the vehicle has experienced severe understeering or oversteering that may cause safety problems, the torque distribution ratio adjustment device 1 will immediately stop the execution of the torque distribution ratio adjustment method described above and brake the corresponding wheels of the vehicle according to strategies known in the prior art based on the specific situation, so as to return the vehicle to a safe driving route. If the evaluation result shows that the vehicle has escaped danger, that is, there is no severe understeering or oversteering, the torque distribution ratio adjustment device 1 resumes the execution of the torque distribution ratio adjustment method.

[0049] Additionally or alternatively, other components of the vehicle, such as a vehicle dynamics control system (VDC), perform a real-time evaluation of the vehicle's driving state, wherein the structure, function and operation method of the vehicle dynamics control system are known from the prior art. If the vehicle dynamics control system finds severe understeering or oversteering that may cause safety problems, it will intervene in the control of the vehicle by braking the corresponding wheels to avoid or overcome the steering problem. At this time, once the corresponding wheels are braked, the torque distribution ratio adjustment device 1 will suspend or end the adjustment of the torque distribution ratio in response to the braking.

[0050] In this way, it is ensured that the torque distribution ratio adjustment method for assisted driving is performed while ensuring the safety of the vehicle and the occupants without bringing any additional risks.

[0051] According to a preferred embodiment of the present invention, a driving assistance system for providing a driving assistance function for a driver is provided, the driving assistance system comprising a torque distribution ratio adjustment device 1 and a switch for activating the torque distribution ratio adjustment device 1. The switch can be configured as an operation button or an operation icon displayed on an operation screen.

[0052] When the torque distribution ratio adjustment device 1 is not activated, the axle torque distribution can be implemented according to the existing strategy in the prior art. In particular, if the vehicle is equipped with a traction control system (TCS), the torque of the front and rear axles is controlled based on the slip ratio set by the traction control system.

[0053] When the driver wants to perform a driving assistance operation, the driver can use the switch to start the driving assistance function implemented by the driving assistance system. Figure 2-3 The described method implements the adjustment of the torque distribution ratio. In particular, the adjustment of the torque distribution ratio implemented by the driving assistance system according to the present invention at least partially replaces the driver's control of the accelerator during the driving assistance operation.

[0054] According to a preferred embodiment, during the operation of the driving assistance system, if it is detected that the driver completely releases the accelerator or at least partially presses the brake pedal, the driving assistance system suspends or ends the adjustment of the torque distribution ratio by the torque distribution ratio adjustment device 1.

[0055] According to a preferred embodiment, the target slip ratio preset by the traction control system is relatively high, and in particular, the target slip ratio preset for the rear axle is greater than the target slip ratio preset for the front axle, so that the vehicle body can oversteer more easily. More preferably, when the driving assistance system is activated, the target slip ratio preset by the traction control system is increased, and in particular, the target slip ratio preset for the rear axle is increased.

[0056] According to another preferred embodiment, the base torque of the rear axle is set to be greater than the base torque of the front axle.

[0057] The present invention is particularly applicable to pure electric split-axle four-wheel drive vehicles and hybrid split-axle four-wheel drive vehicles. However, the present invention can also be applied to other split-axle four-wheel drive vehicles except new energy split-axle four-wheel drive vehicles.

[0058] Although some embodiments have been described, these embodiments are presented by way of example only and are not intended to limit the scope of the invention. The appended claims and their equivalents are intended to cover all modifications, substitutions and changes that fall within the scope and spirit of the invention.

Claims

1. A torque distribution ratio adjustment device (1) for adjusting the torque distribution ratio between the front axle and the rear axle of a split-axle four-wheel drive vehicle, characterized in that: The torque distribution ratio adjustment device (1) is communicatively connected to a detection device for detecting a vehicle state and is configured to: determine a current steering intention of the driver based on a detection signal from the detection device, and then determine an adjustment scheme for the torque distribution ratio based on the determined current steering intention; The torque distribution ratio adjustment device (1) is configured to determine the current steering intention in the following manner: determining the driver's current steering operation and the current vehicle steering trend based on the detection signal and then determining the current steering intention based on the determined current steering operation and the current vehicle steering trend; as well as The torque distribution ratio adjustment device (1) is configured to: if the current steering intention determined is that the current wheel turning operation is aggravating the current vehicle steering tendency, make an adjustment plan to reduce the front axle torque distribution ratio and increase the rear axle torque distribution ratio; If the current steering intention determined is that the current steering operation is counteracting the current vehicle steering trend, an adjustment plan is made to increase the front axle torque distribution ratio and reduce the rear axle torque distribution ratio.

2. The torque distribution ratio adjustment device (1) according to claim 1, characterized in that: The current steering operation is described from two dimensions: the current steering wheel angle position (SAS) and the current steering direction, wherein the current steering direction includes a first direction for rotating the steering wheel toward a return position and a second direction for rotating the steering wheel away from the return position and opposite to the first direction.

3. The torque distribution ratio adjustment device (1) according to claim 2, characterized in that: The torque distribution ratio adjustment device (1) is configured as follows: - when it is determined that the driver is steering in the first direction when the current steering wheel angle position is in the same direction as the current vehicle steering trend, it is determined that the current steering operation is against the current vehicle steering trend; and / or - when it is determined that the driver is steering the wheel in the second direction when the current steering wheel angle position is in the same direction as the current vehicle steering trend, it is determined that the current steering operation is aggravating the current vehicle steering trend; and / or - when it is determined that the driver is steering the wheel in the first direction when the current steering wheel angle position is in a direction different from the current vehicle steering trend, it is determined that the current steering operation is aggravating the current vehicle steering trend; and / or -When it is determined that the driver is steering the wheel in the second direction when the current steering wheel angle position is in a direction different from the current vehicle steering trend, it is determined that the current steering operation is against the current vehicle steering trend.

4. The torque distribution ratio adjustment device (1) according to any one of claims 1 to 3, characterized in that: The detection device comprises a lateral acceleration sensor (6), and the torque distribution ratio adjustment device (1) is configured to adjust the torque distribution ratio based on the vehicle lateral acceleration (a) measured by the lateral acceleration sensor (6). y ) determines the current vehicle turning trend, wherein the measured current vehicle lateral acceleration (a y ) direction represents the current vehicle steering trend.

5. The torque distribution ratio adjustment device (1) according to claim 2 or 3, characterized in that: The detection device comprises a steering wheel angle sensor (5) for measuring a steering wheel angle position (SAS), and the torque distribution ratio adjustment device (1) is configured to calculate a change in the steering wheel angle position based on the measured steering wheel angle position (SAS) and determine whether the steering direction is the first direction or the second direction based on the change.

6. A method for adjusting the torque distribution ratio between the front axle and the rear axle of a split-axle four-wheel drive vehicle, implemented by the torque distribution ratio adjustment device (1) according to any one of the preceding claims.

7. A driving assistance system for assisting a driver's operation, the driving assistance system comprising a torque distribution ratio adjustment device (1) according to any one of claims 1 to 5 and a switch for activating the torque distribution ratio adjustment device (1).

8. The driving assistance system according to claim 7, characterized in that: The driving assistance system is configured to suspend or end the adjustment of the torque distribution ratio by the torque distribution ratio adjustment device (1) once it is detected that the accelerator is released or the brake pedal is depressed.

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