Adaptive steering mode switching method based on EPS

Abstract

The invention discloses a self-adaptive steering mode switching method based on an EPS. The EPS switches steering modes of the EPS according to a vehicle speed signal, a steering wheel angular velocity signal, a driver hand torque signal, an ECU state signal of the EPS, a lane keeping function state signal and a steering mode switching function state signal. The steering modes comprise a normal mode, a comfortable mode, a motion mode and a special hand feeling mode.

Description

Technical Field

[0001] The present invention relates to the technical field of automobile assisted driving, and in particular to an adaptive steering mode switching method based on EPS. Background Art

[0002] As current automobiles have increasingly higher requirements for comfort and intelligence, the electric power steering system (EPS) is also equipped with different steering modes (sport mode and comfort mode, etc.) to adapt to the driving styles of different drivers. Some drivers require a more relaxed and comfortable driving style and can choose comfortable driving, while some require an intense driving style and can choose the corresponding sports mode.

[0003] For most drivers, the driving comfort is reduced due to the vehicle speed and complex and changing road conditions while driving, and they are unable to clearly identify the optimal steering mode they need. Frequent switching between different steering modes affects driving comfort. Therefore, how to balance the switching between free steering mode and adaptive steering mode is a technical problem currently faced. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides an adaptive steering mode switching method based on EPS, EPS switches the steering mode of EPS according to vehicle speed signal, steering wheel angular velocity signal, driver's hand torque signal, EPS ECU status signal, lane keeping function status signal and steering mode switching function status signal; the steering modes include normal mode, comfort mode, sports mode and special feel mode.

[0005] Preferably, when the steering mode switching function status signal is valid and the lane keeping function status signal is valid, the steering mode is switched to the special feel mode.

[0006] Preferably, when the steering mode switching function status signal is valid and the ECU status signal or the lane keeping function status signal is invalid, the current steering mode is maintained.

[0007] Preferably, when the steering mode switching function status signal is valid and the steering mode switching associated state is turned on, the driver dynamic index Di is calculated; when the driver dynamic index Di is greater than a preset sports mode threshold value, the steering mode is switched to the sports mode; when the driver dynamic index Di is less than a preset normal mode threshold value, the steering mode is switched to the normal mode; when the driver dynamic index Di is between the preset sports mode threshold value and the preset normal mode threshold value, the steering mode is switched to the comfort mode.

[0008] Preferably, the driver dynamic index Di is calculated as follows:

[0009]

[0010] Among them, T LongAcc is the duration of longitudinal acceleration greater than the preset threshold, T LaternAcc is the duration of the lateral acceleration greater than the preset threshold, T Emer is the intense turning time, T Brak is the emergency braking time, T1 is the longitudinal acceleration duration, T2 is the lateral acceleration duration, T3 is the turning time, and T4 is the braking time.

[0011] Preferably, when the EPS is powered off normally, the current steering mode is stored; when the EPS is powered on next time, the steering mode is switched to the pre-stored steering mode.

[0012] Preferably, when the EPS is abnormally powered off, the steering mode is switched to the default factory steering mode when the EPS is powered on next time.

[0013] Preferably, the EPS switches the corresponding steering feel curve according to the steering mode and outputs the corresponding power assist motor force.

[0014] The beneficial effects of the present invention are that the steering mode can be switched according to the driver's intention, medium, light and heavy motor assistance can be provided in different vehicle operating environments, the driving experience can be enhanced, and the driving can be memorized and stored as required. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments:

[0016] Figure 1 This is a flow chart of the steering mode switching function of Example 1;

[0017] Figure 2 This is a timing logic diagram of the steering mode switching of Example 1. DETAILED DESCRIPTION

[0018] The following describes the implementation methods of the present invention through specific specific embodiments, and those skilled in the art can fully understand other advantages and technical effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through different specific implementation methods, and the details in this specification can also be applied based on different viewpoints, and various modifications or changes can be made without deviating from the overall design concept of the invention. It should be noted that the following embodiments and the features in the embodiments can be combined with each other in the absence of conflict. The following exemplary embodiments of the present invention can be implemented in a variety of different forms and should not be interpreted as being limited to the specific embodiments described herein. It should be understood that these embodiments are provided to make the disclosure of the present invention thorough and complete, and to fully convey the technical solutions of these exemplary specific embodiments to those skilled in the art.

[0019] Example 1

[0020] The steering mode switching function interacts with the ADAS system or audio control system based on the driver's driving style. When the EPS system determines that the switching conditions are met, the EPS switches the steering mode according to the instructions of the vehicle system, changing the motor assist torque to achieve a change in steering feel.

[0021] The present embodiment provides an adaptive steering mode switching method based on EPS, wherein the steering mode switching function (DMS) of EPS switches the steering mode of EPS according to a vehicle speed signal, a steering wheel angular velocity signal, a driver's hand torque signal, an ECU status signal of EPS, a lane keeping function (LKA) status signal and a steering mode switching function (DMS) status signal; the steering modes include a normal mode (Normal mode is represented by 0), a comfort mode (Comfort mode is represented by 1), a sport mode (Sport mode is represented by 2) and a special feel mode (Special mode is represented by 3).

[0022] If the DMS function is not enabled or there is a fault in the system verification, the DMS will not switch the steering mode and maintain the currently set steering mode; in the event of a serious fault, the state cannot be switched during the current ignition cycle. When a zero-time fault occurs and the fault returns to normal within a period of time, the steering mode can be switched according to the vehicle system or driver's instructions. EPS receives a steering mode request from the vehicle system or the customer, and when the vehicle speed, steering wheel angular velocity, and hand torque are all valid, the steering mode is set according to the request status and the LKA function request status signal.

[0023] The specific execution process of the steering mode switching function (DMS) is as follows: Figure 1When EPS initialization is completed, DMS is activated, and the relevant status signal is valid, when the steering mode switching associated state is off, DMS selects the normal mode (Normal), comfort mode (comfort), and sports mode (Sport) according to the vehicle system command or the driver's command.

[0024] When the switching conditions are met, the corresponding steering modes are responded to according to the request status signal. When there are other request instructions during the switching period, the request signal is repeatedly judged to complete the steering mode switching. When the steering mode switching function status signal is valid and the lane keeping function (LKA) status signal is valid, the free switching of the steering mode is prohibited, and the steering mode is switched to a special feel mode, such as Figure 2 The timing logic diagram of DMS mode switching is shown.

[0025] When the steering mode switching function status signal is valid and the ECU status signal or the lane keeping function status signal is invalid, the current steering mode is maintained.

[0026] When the EPS is powered off normally, the current steering mode is stored; when the EPS is powered on next time, the steering mode is switched to the pre-stored steering mode. When the EPS is powered off abnormally, the steering mode is switched to the default factory steering mode when the EPS is powered on next time. The default factory setting steering mode is comfort mode.

[0027] When the steering mode switching associated state is turned on, in order to provide the driver with the best driving feel, the driving style is judged based on signals such as the steering frequency number, braking frequency number, acceleration frequency number, fierce steering frequency number, sudden acceleration frequency number, and emergency braking frequency number, to clarify whether the driving style is a sporty mode or an economic or normal mode; while the driver is driving the vehicle, the above six parameters are continuously updated. If the number of records exceeds a certain limit, the driver's dynamic index Di can be calculated based on the current recorded data.

[0028] When the driver dynamic index Di is greater than the preset sports mode threshold value, the steering mode is switched to the sports mode; when the driver dynamic index Di is less than the preset normal mode threshold value, the steering mode is switched to the normal mode; when the driver dynamic index Di is between the preset sports mode threshold value and the preset normal mode threshold value, the steering mode is switched to the comfort mode.

[0029] The calculation method of the driver dynamic index Di is:

[0030]

[0031] Among them, T LongAcc is the duration of longitudinal acceleration greater than the preset threshold, TLaternAcc is the duration of the lateral acceleration greater than the preset threshold, T Emer is the intense turning time, T Brak is the emergency braking time, T1 is the longitudinal acceleration duration, T2 is the lateral acceleration duration, T3 is the turning time, and T4 is the braking time.

[0032] EPS pre-processes the status signal, request signal and mode-related signal respectively, judges and outputs the steering mode status, outputs and switches different steering feel curves, and then selects the corresponding feel curve according to the steering mode status to output the motor force under the current steering mode status.

[0033] If the DMS function is not enabled or there is a fault in the system verification, the DMS will not switch the steering mode and maintain the currently set steering mode; in the event of a serious fault, the state cannot be switched during the current ignition cycle. When a zero-time fault occurs and the fault returns to normal within a period of time, the steering mode can be switched according to the vehicle system or driver's instructions. EPS receives a steering mode request from the vehicle system or the customer, and when the vehicle speed, steering wheel angular velocity, and hand torque are all valid, the steering mode is set according to the request status and the LKA function request status signal.

[0034] The present invention has been described in detail above through specific implementation modes and embodiments, but these do not constitute limitations of the present invention. Without departing from the principles of the present invention, those skilled in the art may also make many variations and improvements, which should also be regarded as the protection scope of the present invention.

Claims

1. An adaptive steering mode switching method based on EPS, characterized in that: EPS switches the steering mode of EPS according to the vehicle speed signal, steering wheel angular velocity signal, driver's hand torque signal, EPS ECU status signal, lane keeping function status signal and steering mode switching function status signal; the steering modes include normal mode, comfort mode, sports mode and special feel mode.

2. The EPS-based adaptive steering mode switching method according to claim 1, characterized in that: When the steering mode switching function status signal is valid and the lane keeping function status signal is valid, the steering mode is switched to the special feel mode.

3. The EPS-based adaptive steering mode switching method according to claim 1, characterized in that: When the steering mode switching function status signal is valid and the ECU status signal or the lane keeping function status signal is invalid, the current steering mode is maintained.

4. The EPS-based adaptive steering mode switching method according to claim 1, characterized in that: When the steering mode switching function state signal is valid and the steering mode switching associated state is on, the driver dynamic index Di is calculated; When the driver dynamic index Di is greater than a preset sports mode threshold, the steering mode is switched to the sports mode; When the driver dynamic index Di is less than a preset normal mode threshold value, the steering mode is switched to the normal mode; When the driver dynamic index Di is between a preset sports mode threshold value and a preset normal mode threshold value, the steering mode is switched to a comfort mode.

5. The EPS-based adaptive steering mode switching method according to claim 4, characterized in that: The calculation method of the driver dynamic index Di is: Among them, T LongAcc is the duration of longitudinal acceleration greater than the preset threshold, T LaternAcc is the duration of the lateral acceleration greater than the preset threshold, T Emer is the intense turning time, T Brak is the emergency braking time, T1 is the longitudinal acceleration duration, T2 is the lateral acceleration duration, T3 is the turning time, and T4 is the braking time.

6. The EPS-based adaptive steering mode switching method according to claim 1, characterized in that: When the EPS is powered off normally, the current steering mode is stored; when the EPS is powered on next time, the steering mode is switched to the pre-stored steering mode.

7. The EPS-based adaptive steering mode switching method according to claim 6, characterized in that: When the EPS is powered off abnormally, the steering mode is switched to the default factory steering mode the next time the EPS is powered on.

8. The EPS-based adaptive steering mode switching method according to claim 1, characterized in that: EPS switches the corresponding steering feel curve according to the steering mode and outputs the corresponding power assist motor force.

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