An EPS-based integrated control method for parking and driving

Abstract

The application discloses a kind of based on EPS's line park integrated control method, it is related to automobile intelligent driving technical field, to solve the problem of response delay, moment mutation and poor smoothness caused by the need to rehandshake when switching the driving and parking function in prior art, the technical scheme is that EPS and upper control system establish the same handshake logic and define state machine;In active state, distinguish driving or parking control logic according to upper instruction, no need to rehandshake when switching function;During switching process, the smooth processing of the output torque is reduced and raised slowly, and the buffer time can be adjusted adaptively according to the vehicle speed;The application realizes the seamless switching of driving and parking function, the response time is short, the output torque is smooth, the overshoot is small, and the user experience of intelligent driving lateral control is significantly improved.

Description

Technical Field

[0001] This invention relates to the field of intelligent driving technology for automobiles, specifically to a driving and parking integrated control method based on EPS. Background Technology

[0002] With the rapid development of intelligent driving technology, more and more automakers are integrating highway navigation functions. The originally separate driving (such as lane keeping assist, LKA) and parking (such as automatic parking assist, APA) functions are no longer strictly physically separated, but are trending towards a highly integrated driving and parking control strategy.

[0003] This strategy places higher control demands on the EPS control unit, which acts as the vehicle's lateral control actuator. In existing technologies, driving and parking functions often employ different handshake logics, or require re-handshaking and initialization when switching functions. This results in a delay in the transfer of control during the switching between driving and parking modes, and the output torque is prone to sudden changes, leading to uneven lateral control and impacting driving experience and safety. Therefore, there is an urgent need for an integrated driving and parking control method that can achieve smooth switching without repeated handshakes. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the existing defects and provide an integrated control method for navigation and berthing based on EPS, which can effectively solve the problems in the background art.

[0005] To achieve the above objectives, this invention discloses an integrated navigation and parking control method based on EPS, the technical solution of which includes the following steps: Step 1: The EPS controller establishes the same handshake logic with the upper-level control system, and defines the ADAS functional state machine of the EPS based on the handshake logic; the state machine includes suppressed state, available state, active state and fault state; Step 2: When the state machine is in an available state and the communication status is normal, the EPS controller receives an activation request signal and a function mode command from the upper control system; the function mode command includes driving mode, parking mode, and emergency avoidance mode. Step 3: When the EPS controller receives the activation signal of the corresponding different functional modules, it activates the corresponding driving control logic or parking control logic and outputs the corresponding auxiliary torque according to the activated function. When the EPS controller receives a function mode command to switch between driving mode and parking mode while in the active state, it performs a smooth switching process for output torque. By adopting a unified handshake logic and state machine, the switching between driving and parking functions does not require a new handshake, and the response time is reduced to less than 100ms.

[0006] As a preferred embodiment of the present invention, the output torque smoothing switching process in step 3 specifically includes: When the function mode command switches from driving mode to parking mode, the EPS controller executes the first switching logic: The currently active driving control logic is suspended, and the currently calculated driving output torque is gradually reduced until it is reduced to a preset safety threshold. After the driving output torque gradually decreases to a safe threshold, the calculation of parking torque is initiated, and the calculated parking output torque is gradually increased until the target parking torque is reached.

[0007] As a preferred embodiment of the present invention, the output torque smoothing switching process in step S3 specifically includes: When the function mode command switches from driving mode to parking mode, the EPS controller executes the second switching logic: The torque superposition calculation for suspending driving function is performed, and the current driving output torque is used as the initial torque A for gradual reduction. Simultaneously, the torque calculation of the parking function is initiated, and the calculated parking target torque is used as the target torque B for gradual increase. When the initial torque A gradually decreases to be equal to the target torque B gradually increases to a certain value, the merging and switching from driving output torque to parking output torque is completed.

[0008] As a preferred embodiment of the present invention, the gradual descent and gradual ascent processes employ a linear ramp function to gradually change the torque, and the formula is as follows: in: : Indicates the final output torque of the PAC function; : Indicates the initial output torque at which the torque switching begins; This indicates the desired final output torque. This represents the expected time for the torque to gradually decrease; : This indicates the control cycle time.

[0009] As a preferred embodiment of the present invention, the preset descent time or descent time... The time is 100 milliseconds, and the preset safety threshold is zero torque; through gradual rise and fall and convergence superposition logic, the torque smoothness during the switching process is guaranteed, the overshoot is less than 3% of the requested angle, and the steady-state error is less than 0.3.

[0010] As a preferred embodiment of the present invention, the state transition conditions of the state machine specifically include: C1: When the EPS's ADAS status is normal, the communication status is normal, and there is no activation request from the upper layer, the state machine enters or remains in an available state. C2: When the upper layer requests activation and the control mode is APA activation or LKA activation, the state machine transitions from the available state to the active state. C3: When the upper layer request is no request or the control mode is inactive, and the ADAS status and communication status of EPS are both normal, the state machine returns from the active state to the available state. C4: When the communication status is abnormal, the state machine jumps to the fault state; C5: When the EPS is inactive, an error occurs that seriously affects the power assist function (TAS torque sensor failure / MCU failure / drive failure / CAN failure / BUSOFF failure), and the system jumps to the fault state.

[0011] As a preferred technical solution of the present invention, in the active state, the EPS controller distinguishes between executing a driving path or a parking path based on the three types of status information sent by the upper control system; when switching between driving and parking functions during the function activation period, there is no need to re-execute the handshake activation process.

[0012] As a preferred technical solution of the present invention, the EPS controller adds torque easing or easing logic during function activation, exit, and function switching. The basic calibration values ​​for activation easing time and exit easing time are both 100 milliseconds, and can be adaptively adjusted according to vehicle speed. The easing time can be dynamically adjusted according to vehicle speed to adapt to the smoothness requirements under different operating conditions. It supports a safe exit mechanism under extreme operating conditions, improving system robustness.

[0013] As a preferred embodiment of the present invention, the smooth switching process makes the function switching response time less than 100 milliseconds and the overshoot of the output torque less than 3% of the requested angle.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: By adopting a unified handshake logic and state machine, the switching between driving and parking functions does not require a new handshake, and the response time is shortened to less than 100ms; through gradual ascent and descent and merging superposition logic, the torque smoothness during the switching process is guaranteed, the overshoot is less than 3% of the requested angle, and the steady-state error is less than 0.3; the descent time can be dynamically adjusted according to the vehicle speed to adapt to the smoothness requirements under different operating conditions; and a safe exit mechanism is supported under extreme operating conditions to improve the robustness of the system. Attached Figure Description

[0015] Figure 1 This is the overall flow chart of the EPS berthing integrated control method of the present invention; Figure 2 This is the state transition diagram of the ADAS functional state machine of the present invention; Figure 3 This is a diagram defining the state transition conditions C1-C4 of the present invention; Figure 4 This is the control block diagram of the present invention (Signal interaction between EPS and the upper control system). Figure 5 This is a graph showing the relationship between buffer time and vehicle speed in this invention. Detailed Implementation

[0016] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] Example 1 like Figures 1 to 5 As shown, this invention discloses an integrated navigation and parking control method based on EPS, and the technical solution adopted includes the following steps: Step 1: Unify the handshake and state machine definitions; The EPS controller uses the same handshake logic as the upper-level control system, and defines the ADAS functional state machine of the EPS based on this handshake logic; the state machine includes Inhibit, Available, Active and Failure states. Step 2: Function activation and mode differentiation; When the state machine is in an available state and communication is normal, the EPS controller receives an activation request signal and a function mode instruction from the upper control system. The function mode instruction includes driving mode, parking mode, and emergency avoidance mode. After a successful handshake, the EPS distinguishes between executing a driving path or a parking path based on the three types of state information sent by the upper control system. When switching between driving and parking functions during function activation, there is no need to re-execute the handshake activation process. Step 3: Smooth torque switching control; When activated, when the function mode command switches from driving mode to parking mode or vice versa, the EPS controller performs a smooth switching process for the output torque; the smooth switching process includes gradually reducing the current output torque, gradually increasing the target output torque, and optional torque merging and superposition logic.

[0018] Furthermore, the smooth switching process employs a linear ramp function for gradual torque change, as shown in the following formula: in: : Indicates the final output torque of the PAC function; : Indicates the initial output torque at which the torque switching begins; This indicates the desired final output torque. This represents the expected time for the torque to gradually decrease; : This indicates the control cycle time.

[0019] Step 4: Gradual ascent and descent throughout the entire process; During function activation, exit, and function switching, torque easing or easing logic is added. The basic calibration values ​​for activation easing time and exit easing time are both 100 milliseconds, and can be adaptively adjusted to 100ms according to vehicle speed. The safety threshold is set to zero torque.

[0020] System state machine definition and jump logic After the EPS controller is powered on, it first performs a self-test. If the self-test detects any fault (such as sensor malfunction, motor failure, etc.), the state machine enters the inhibit state and sends an "EPS unavailable" signal to reject all ADAS activation requests. If the self-test is successful, the EPS controller establishes communication with the upper-level control system and continuously monitors three key signals: EPS_AD_State: The ADAS function status of EPS itself; AD_CommState: Communication status with the upper-level control system; ADRequestCtrl: Activation request (Request / NoRequest) from the upper-level control system. State transition conditions C1: When EPS_AD_State is OK, AD_CommState is OK, and ADRequestCtrl is NoRequest, the state machine enters or remains in the Available state. In this state, EPS is ready and can respond to activation commands at any time; C2: In the Available state, if ADRequestCtrl is received as Request and the upper control mode (AD_ControlMode) is APAActive or LKAActive, the state machine immediately jumps to the active state; at this time, EPS starts to output the corresponding auxiliary torque according to the control mode; C3: In the Active state, if ADRequestCtrl becomes NoRequest, or AD_ControlMode becomes NoActive, and EPS_AD_State and AD_CommState remain OK, the state machine returns to the Available state and stops outputting ADAS-related torques. C4: In any state, if AD_CommState becomes non-OK (e.g., CAN communication timeout), the state machine unconditionally jumps to the fault state, prohibits any ADAS torque output, and reports the fault to the vehicle controller; C5: When the EPS is inactive, an error occurs that seriously affects the power assist function (TAS torque sensor failure / MCU failure / drive failure / CAN failure / BUSOFF failure), and the system jumps to the fault state.

[0021] Handshake activation and function differentiation Scenario setting: The vehicle is driving on a highway and the driver activates the lane keeping assist function (LKA).

[0022] The upper-level control system sends: ADRequestCtrl=Request, AD_ControlMode=LKAActive; EPS is in the Available state at this time (no fault in self-test, normal communication); condition C2 is met, and the state machine enters Active.

[0023] EPS identifies the driving mode based on AD_ControlMode and calls the driving control logic. The driving control logic takes the target steering angle or target torque sent by the upper layer as input, combines the vehicle's current speed, steering wheel angle and other information to calculate the auxiliary torque that needs to be superimposed, and outputs it through the motor drive unit.

[0024] Function switching scenario: The vehicle enters the parking lot and the driver triggers Automatic Parking (APA).

[0025] The upper-level control system switches AD_ControlMode from LKAActive to APAActive without changing ADRequestCtrl (which remains Request). Since this technical method uses a unified handshake logic, EPS does not need to exit the Active state, nor does it need to re-execute the handshake process (i.e., it does not need to become Available first and then reactivate). Instead, it directly recognizes the mode change in the Active state.

[0026] After the EPS detects that the mode has switched from driving to parking, it executes the following smooth switching logic.

[0027] Torque smoothing during driving and parking transitions (taking the first logic as an example, applicable to low vehicle speeds or the initial stage of parking). At the switching moment, the driving control logic is outputting a gradually changing auxiliary torque (denoted as torque A); if it is directly cut off and switched to parking torque, it will cause a sudden change in the steering wheel. This technical method employs a gradual descent + gradual ascent mechanism; Suspend driving logic: The EPS controller suspends the update of the integral term of the driving control law, but keeps the current output torque value unchanged; Torque reduction: The current output torque is gradually reduced to a safe threshold (e.g., zero torque) by a preset descent ramp time; the descent process adopts a linear function: the output torque is reduced by (initial torque / descent time × scheduling cycle) in each scheduling cycle.

[0028] Parking torque gradual increase: As the driving torque begins to gradually decrease (or after it drops to the safe threshold), the parking torque calculation is initiated; the parking control logic calculates the desired target torque (denoted as torque B) based on the APA path planning results; the EPS gradually increases the target torque from the safe threshold to full output using a preset gradual ramp time.

[0029] Combined output: When the descent has not yet completely returned to zero but the ascent has already begun, the final torque acting on the steering motor is (current descent value for driving + current ascent value for parking); since the slopes of the two ramps are coordinated, the combined torque will not have abrupt changes or overshoot; when the driving torque drops to the safety threshold, the parking torque just rises to the target value, completing a seamless switch.

[0030] The second optional logic (convergence and superposition): If it is required that the total torque remain continuous and not drop to the safety threshold during the switching process, the driving torque is gradually reduced from the initial value A, while the parking torque is gradually increased from zero. When the two values ​​are equal, the driving torque continues to gradually decrease and the parking torque continues to gradually increase. However, after this intersection point, the weight of the driving torque is gradually transferred to the parking torque until the driving torque completely exits. This method can further shorten the total switching time.

[0031] Components not described in detail in this article are existing technologies.

[0032] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for integrated navigation and berthing control based on EPS, characterized in that, Includes the following steps: Step 1: The EPS controller establishes the same handshake logic with the upper-level control system, and defines the ADAS functional state machine of the EPS based on the handshake logic; the state machine includes suppressed state, available state, active state and fault state; Step 2: When the state machine is in an available state and the communication status is normal, the EPS controller receives an activation request signal and a function mode command from the upper control system; the function mode command includes driving mode, parking mode, and emergency avoidance mode. Step 3: When the EPS controller receives the activation signal of the corresponding different functional modules, it activates the corresponding driving control logic or parking control logic and outputs the corresponding auxiliary torque according to the activated function. Specifically, when the EPS controller receives a function mode command in the active state to switch between driving mode and parking mode, it performs a smooth switching process for output torque.

2. The EPS-based integrated navigation and berthing control method according to claim 1, characterized in that, The smooth switching of output torque in step 3 specifically includes: When the function mode command switches from driving mode to parking mode, the EPS controller executes the first switching logic: The currently active driving control logic is suspended, and the currently calculated driving output torque is gradually reduced until it is reduced to a preset safety threshold. After the driving output torque gradually decreases to a safe threshold, the calculation of parking torque is initiated, and the calculated parking output torque is gradually increased until the target parking torque is reached.

3. The EPS-based integrated navigation and berthing control method according to claim 1, characterized in that, The output torque smoothing switching process in step S3 specifically includes: When the function mode command switches from driving mode to parking mode, the EPS controller executes the second switching logic: The torque superposition calculation for suspending driving function is performed, and the current driving output torque is used as the initial torque A for gradual reduction. Simultaneously, the torque calculation of the parking function is initiated, and the calculated parking target torque is used as the target torque B for gradual increase. When the initial torque A gradually decreases to be equal to the target torque B gradually increases to a certain value, the merging and switching from driving output torque to parking output torque is completed.

4. The EPS-based integrated navigation and berthing control method according to claim 2 or 3, characterized in that: The gradual descent and ascent processes employ a linear ramp function to gradually change the torque, and its formula is as follows: in: : Indicates the final output torque of the PAC function; : Indicates the initial output torque at which the torque switching begins; This indicates the desired final output torque. This represents the expected time for the torque to gradually decrease; : This indicates the control cycle time.

5. The EPS-based integrated navigation and parking control method according to claim 4, characterized in that: Preset descent or ascent time The time limit is 100 milliseconds, and the preset safety threshold is zero torque.

6. The EPS-based integrated navigation and berthing control method according to claim 1, characterized in that, The specific conditions for state transitions in a state machine include: C1: When the EPS's ADAS status is normal, the communication status is normal, and there is no activation request from the upper layer, the state machine enters or remains in an available state. C2: When the upper layer requests activation and the control mode is APA activation or LKA activation, the state machine transitions from the available state to the active state. C3: When the upper layer request is no request or the control mode is inactive, and the ADAS status and communication status of EPS are both normal, the state machine returns from the active state to the available state. C4: When the communication status is abnormal, the state machine jumps to the fault state; C5: When the EPS is inactive, an error occurs that seriously affects the power assist function, and the system jumps to a fault state.

7. The EPS-based integrated navigation and parking control method according to claim 1, characterized in that: In the active state, the EPS controller distinguishes between executing a driving path or a parking path based on the three types of status information sent by the upper control system; when switching between driving and parking functions during function activation, there is no need to re-execute the handshake activation process.

8. The EPS-based integrated navigation and parking control method according to claim 1, characterized in that: The EPS controller incorporates torque ramp-up or ramp-down logic during function activation, deactivation, and function switching. The activation ramp-up time and deactivation ramp-down time are both calibrated to 100 milliseconds and can be adaptively adjusted according to vehicle speed.

9. The EPS-based integrated navigation and parking control method according to claim 1, characterized in that: Smooth switching processing ensures that the function switching response time is less than 100 milliseconds and the overshoot of the output torque is less than 3% of the requested angle.

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