Control method of automobile electronic gear shifter integrated with electronic parking braking function

Abstract

The invention relates to a control method of an automobile electronic gear shifter integrated with an electronic parking brake function, belongs to the technical field of automobile electronic control, and is realized by a system comprising an IPB controller, a gear shifter controller, a relay module and EPB calipers. According to the method, after the system is powered on, double-controller self-inspection is executed in parallel, in a normal mode, an IPB controller controls EPB calipers in a master mode, and a gear shifter controller monitors the IPB state in real time; when IPB faults or disconnection is detected, safety conditions are verified, hardware interlocking type control right switching is achieved through a relay, and EPB control is taken over by a gear shifter controller; and the control right is returned after the IPB is recovered. According to the method, the fault redundancy capability and the control response speed of the EPB system are improved, the hardware cost is reduced, and the adaptability is high.

Description

Technical Field

[0001] This invention relates to a method for controlling an electronic gear shifter in automobiles, and more particularly to a method for controlling an electronic gear shifter in automobiles that integrates an electronic parking brake function. Background Technology

[0002] With the rapid development of automotive drive-by-wire chassis technology, electronic parking brake (EPB) systems and electronic gear shifters have become standard core components in passenger vehicles. Currently, the conventional technology involves integrating these two systems to simplify the layout of in-vehicle operating components. However, existing technologies only achieve physical integration of the operating interface, without integrating the EPB control logic and actuation capabilities. When the vehicle's main parking brake (IPB) controller fails, redundant backup of the EPB function cannot be achieved, posing a safety risk of parking function failure.

[0003] Meanwhile, existing technologies have proposed various solutions for redundant control of the EPB system. For example, in the event of an EPB controller failure, the vehicle control unit (VCU) can take over EPB control as a redundant unit, which can improve the operational reliability of the EPB system to some extent. Another approach uses a dual-MCU (master and slave) redundant architecture within a single electronic control unit (ECU) to achieve backup control of the EPB and P-gear functions. However, the former relies on the computing power and hardware resources of the vehicle's VCU, increasing the control load on the VCU, and lacks hardware-level control loop interlocking, making it prone to hardware damage due to conflicts between the two control signals. The latter is only a redundancy design within a single ECU; when the entire ECU experiences power or communication failures, the parking and P-gear backup functions will still fail simultaneously, failing to achieve cross-unit physically isolated independent redundancy protection.

[0004] In summary, existing integrated designs for EPB and electronic gear shifters mostly focus on the structural and operational interface levels. EPB redundancy control schemes either suffer from excessive control unit load and lack hardware interlocking mechanisms, or fail to achieve physically isolated cross-unit independent redundancy protection. This makes it difficult to balance the integration, response speed, and fault redundancy capabilities of the EPB system while controlling overall vehicle costs. When the vehicle's IPB main controller experiences communication interruptions or hardware failures, the parking function may become paralyzed, posing a certain driving safety hazard. This is the core technical problem that this invention aims to solve.

[0005] In view of the above-mentioned shortcomings, the designer actively researched and innovated in order to create a control method for an automotive electronic gear shifter that integrates electronic parking brake function, making it more valuable for industrial applications. Summary of the Invention

[0006] To address the aforementioned technical problems, the purpose of this invention is to provide a method for controlling an electronic gear shifter in a car that integrates electronic parking brake functionality.

[0007] The present invention discloses a method for controlling an electronic gear shifter in an automotive system with integrated electronic parking brake functionality. This method relies on a control system comprising an IPB controller (Integrated Power Brake), a gear shifter controller, a CAN bus, a relay module, an EPB caliper, a vehicle speed detection module, a gear position detection module, and a P button. The IPB controller is connected to the drive motor of the EPB caliper via a first hardwire through the normally closed terminal of the relay module, and is connected to the gear shifter controller via the CAN bus. The gear shifter controller is connected to the drive motor of the EPB caliper via a second hardwire through the relay module, and is connected to the IPB controller, the vehicle speed detection module, and the gear position detection module via the CAN bus. It is also connected to the P button via a hardwire. The relay module is a single-pole double-throw relay module, connected to the first hardwire and the second hardwire respectively. The gear shifter controller controls the switching of the relays via I / O ports, ensuring that only one of the first or second hardwires is connected to the drive motor of the EPB caliper at any given time. The method includes the following steps: Step 1: After the system is powered on, the IPB controller self-test and the shifter controller self-test are performed in parallel. If both self-tests pass, the system enters normal mode. If either self-test fails, the system enters fault handling mode.

[0008] Step 2: In normal mode, the IPB controller performs parking control on the EPB caliper through the first hardwire. At the same time, the shifter controller continuously monitors the heartbeat status signal (0x204 signal) with a period of 10ms sent by the IPB controller via the CAN bus, as well as the backup request signal (0x205 signal) sent by the IPB controller.

[0009] Step 3: When the shift controller detects that it has not received a heartbeat status signal for 50 consecutive cycles or has received the backup request signal, it triggers the backup takeover process, verifying the backup takeover safety conditions through the vehicle speed detection module and the gear position detection module. As an optimization, 50 cycles can be preferred.

[0010] Step four: If the backup takeover security condition verification is successful, the shifter controller controls the relay module to disconnect the first hard wire and connect the second hard wire through the I / O port to enter the backup mode.

[0011] Step 5: In backup mode, the shifter controller performs clamping or releasing control on the EPB caliper via the second hardwire, while continuously monitoring the self-test pass signal (0x203 signal) sent by the IPB controller to confirm the recovery status of the IPB controller.

[0012] Step six: When the shift controller detects that the IPB controller has returned to normal and the safety conditions for returning control have been verified, it controls the relay module to connect the first hardwire and disconnect the second hardwire through the I / O port, returns control to the IPB controller, and returns to the normal mode.

[0013] Furthermore, in the above-mentioned automotive electronic shifter control method integrating electronic parking brake function, in step one, the self-test of the IPB controller and the shifter controller both include motor drive circuit detection, sensor circuit detection, communication interface detection, and power circuit detection. After the self-test passes, both the IPB controller and the shifter controller send a normal self-test signal to the instrument panel via the CAN bus. If the self-test fails, the corresponding fault code is recorded by the IPB controller and sent to the instrument panel.

[0014] Furthermore, in the above-mentioned automotive electronic gear shifter control method integrating electronic parking brake function, the execution steps of the fault handling mode in step one are as follows: if the self-test failure item is a recoverable fault, then the fault recovery process is executed, and after successful recovery, the normal mode is entered; if the self-test failure item is an unrecoverable fault, then the vehicle's gear shifting operation is restricted and a fault prompt is sent to the instrument panel.

[0015] Furthermore, in the above-mentioned automotive electronic shifter control method integrating electronic parking brake function, in step two, the shifter controller monitors the heartbeat status signal by: acquiring the heartbeat status signal on the CAN bus every 10ms; if no valid heartbeat status signal is acquired in 50 consecutive acquisitions, it is determined that the heartbeat status signal has not been received for 50 consecutive cycles.

[0016] Furthermore, in the above-mentioned automotive electronic gear shifter control method integrating electronic parking brake function, in step three, the backup takeover safety conditions are: the real-time vehicle speed corresponding to the vehicle speed signal collected by the vehicle speed detection module is less than 3km / h, and the vehicle gear corresponding to the gear signal collected by the gear position detection module is P gear.

[0017] Furthermore, in the above-mentioned automotive electronic shifter control method integrating electronic parking brake function, in step four, while the shifter controller controls the relay module to switch, it sends a backup mode activation prompt signal to the instrument panel via the CAN bus, and at the same time stops responding to the parking control command sent by the IPB controller.

[0018] Furthermore, in the aforementioned automotive electronic shifter control method integrating electronic parking brake function, step five, in which the shifter controller performs clamping control on the EPB caliper in backup mode, is as follows: Step A: When the vehicle is detected to be in P gear or the driver triggers the P button, the shift controller controls the drive motor of the EPB caliper to start with a maximum current of 20A for 30-100ms to overcome static friction. Step B: Adjust the PWM duty cycle using the PID algorithm (PID, Proportional-Integral-Derivative) to stabilize the operating current of the drive motor within the range of 17A±1A and perform uniform clamping action. Step C: Maintain a working current of 17A for 500ms to establish the target clamping force, then switch to a low current holding mode of 1A, and simultaneously illuminate the indicator light of the P button to indicate that the parking is complete.

[0019] Furthermore, in the aforementioned automotive electronic shifter control method integrating electronic parking brake function, step five, in backup mode, involves the shifter controller performing release control on the EPB caliper as follows: Step A: When the vehicle is detected to have moved out of P gear or the driver has triggered the P button to release the operation, the drive motor of the EPB caliper is controlled to rotate in the opposite direction to quickly release the travel of 0.7-1.5mm, forming a safe distance between the brake pad and the brake disc, with a time of no more than 200ms. Step B: The shifter controller reduces the speed of the drive motor to perform a slow release action, with a total release time not exceeding 1.5 seconds; Step C: During the release process of the shifter controller, the operating current of the drive motor is monitored in real time. If the instantaneous current exceeds 16A, or if the current is sampled once every 150ms and the average current value after taking 3 samples exceeds 10A, the release action is stopped immediately, the corresponding fault code is recorded and sent to the instrument panel.

[0020] Furthermore, in the above-mentioned automotive electronic shifter control method integrating electronic parking brake function, in step five, in backup mode, the shifter controller performs the linkage control between gear position and EPB as follows: when the vehicle is detected to be in P gear and the real-time vehicle speed is less than 3km / h, the clamping control of the EPB caliper is automatically triggered; when the vehicle is detected to be out of P gear, the release control of the EPB caliper is automatically triggered.

[0021] Furthermore, in the above-mentioned automotive electronic shifter control method integrating electronic parking brake function, the safety condition for handing over control in step six is ​​that the real-time vehicle speed corresponding to the vehicle speed signal collected by the vehicle speed detection module is less than 3km / h, and the EPB caliper is in a stable clamping state.

[0022] By means of the above-described solution, the present invention has at least the following advantages: 1. This invention uses the vehicle's existing gear shifter controller as an independent redundant control unit of the EPB system, and works with a single-pole double-throw relay module to achieve hardware-level control interlocking switching, solving the industry pain point of complete paralysis of the parking function after the failure of the main controller in the traditional discrete architecture. In the event of communication interruption or hardware failure of the IPB controller, seamless control takeover can be achieved, significantly reducing safety risks such as vehicle rollover caused by parking function failure, and improving the fault redundancy design of the parking system.

[0023] 2. This invention deeply integrates the EPB backup control function into the existing gear shift controller hardware platform, eliminating the need for an additional independent redundant control unit. This reduces the number of electronic control units in the vehicle and simultaneously lowers the overall cost of hardware materials, vehicle wiring harnesses, and installation layout. Furthermore, by directly driving the EPB actuator with hardwired wiring from the gear shift controller, the transmission delay caused by traditional cross-controller CAN communication is eliminated, effectively improving the response speed and execution accuracy of parking control.

[0024] 3. This invention incorporates multi-dimensional safety condition verification and fault detection logic throughout the entire process of power-on initialization, mode switching, parking action execution, and control handover. By imposing dual safety constraints based on vehicle speed and gear position, it avoids erroneous mode switching and parking actions under unsafe conditions. Simultaneously, it achieves full-cycle fault diagnosis and graded processing for hardware circuits, communication links, and actuators, minimizing safety risks during driving while ensuring the availability of the parking function.

[0025] 4. The hardware architecture provided by this invention is fully compatible with the electronic shifter and EPB system layout of existing mainstream passenger vehicles, requiring no large-scale modifications to the vehicle's braking system and shift actuators. The software control logic can flexibly adjust control parameters according to the load characteristics of different vehicle models, exhibiting extremely high adaptability. Simultaneously, the system supports unified UDS diagnostic services and CAN bus online software upgrades, significantly simplifying after-sales troubleshooting and software iteration processes, and reducing the maintenance costs throughout the vehicle's lifecycle.

[0026] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0027] Figure 1 This is a schematic diagram illustrating the implementation process of an electronic gear shifter control method for vehicles with integrated electronic parking brake function.

[0028] Figure 2 This is a schematic diagram of the layout of the automotive electronic gear shifter control system with integrated electronic parking brake function constructed by the present invention. Detailed Implementation

[0029] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0030] like Figures 1 to 2 The unique feature of this automotive electronic shifter control method with integrated electronic parking brake function is that it can be implemented based on the automotive electronic shifter control system with integrated electronic parking brake function. This system mainly consists of an IPB controller, a shifter controller, a CAN bus, a relay module, an EPB caliper, a vehicle speed detection module, a gear position detection module, and a P button. The connection relationship and functional coordination of each component provide hardware support for the implementation of the control method, as detailed below.

[0031] The IPB controller is directly connected to the drive motor of the EPB caliper via a first hardwire, and simultaneously establishes bidirectional communication with the shifter controller via a CAN bus to achieve data exchange and status synchronization. The shifter controller is connected to the drive motor of the EPB caliper via a second hardwire through a relay module. It transmits signals to the IPB controller, vehicle speed detection module, and gear position detection module via a CAN bus, and is also directly connected to the P button via a hardwire to receive the driver's manual parking command.

[0032] Meanwhile, the relay module uses a single-pole double-throw relay module, connected to the first and second hard wires respectively. The shifter controller controls its on / off switching via high and low level signals output from the I / O port. Its core function is to ensure that only one of the first or second hard wires is connected to the EPB caliper drive motor at any given time, avoiding conflict between the two control signals at the hardware level and ensuring the uniqueness and safety of the control logic. During implementation, the IPB controller uses a 32-bit automotive-grade microprocessor as its core, incorporating hydraulic brake control logic, electronic parking brake control logic, and fault diagnosis logic, comprehensively covering the parking control and fault monitoring needs under normal conditions. Its power input is connected to the vehicle's 12V power network, and it has two independent DC-DC power conversion circuits, providing stable operating power to the microprocessor core circuit, peripheral drive circuit, and communication circuit, ensuring stable operation of each module. Furthermore, the IPB controller has a built-in H-bridge motor drive circuit, capable of outputting a maximum drive current of 25A to meet the power requirements of the EPB caliper drive motor. The built-in current acquisition circuit and position acquisition circuit can acquire the working current of the EPB caliper drive motor and the position signal of the caliper piston in real time, providing data support for clamping force closed-loop control and fault diagnosis.

[0033] The gear shift controller is designed with an ARM Cortex-M3 32-bit automotive-grade microprocessor, integrating electronic shift control logic, EPB backup control logic, relay switching control logic, signal monitoring logic, fault diagnosis logic, and gear position and EPB linkage control logic, thus possessing dual functions of shift control and EPB backup control. Its power input is also connected to the vehicle's 12V power network, integrating a high-efficiency DC-DC power conversion circuit that can output stable 5V and 3.3V operating power, and supports external power supply sleep / wake-up control. The power circuit incorporates overvoltage, overcurrent, overheat, and short-circuit protection functions, adapting to the complex power environment inside the vehicle.

[0034] According to a preferred embodiment of the present invention, the sensor signal input terminal of the gear shift controller is connected to the gear position detection module. This gear position detection module adopts a design of multiple Hall sensor arrays and detects the gear lever position based on the MBB (Multiple Binary Bits) algorithm. Specifically, the MBB algorithm converts the output signal of each Hall sensor into a binary digital signal. The binary signals of multiple Hall sensors are combined to form a unique binary code. Different gears correspond to different binary codes. By comparing the code with a preset gear position code table, the system can accurately identify the current gear, achieving accurate identification of gears such as P, R, N, and D. The gear position detection resolution can reach 0.1mm, effectively improving the reliability and anti-interference capability of gear position identification.

[0035] Furthermore, the shifter controller incorporates a built-in 12-bit high-precision ADC circuit, which is connected to the P button via a hard wire. This allows for real-time acquisition of the P button's analog signal, enabling accurate detection of the P button's status. It also supports open-circuit, short-circuit, and sticking fault detection for the P button, preventing accidental triggering of parking commands due to button malfunctions. Its drive output terminal incorporates an H-bridge motor drive circuit, which can directly drive the EPB actuator motor with a maximum output current of 20A. This H-bridge motor drive circuit includes a current sampling resistor and overcurrent protection circuit, enabling real-time acquisition of the drive motor's operating current. This achieves closed-loop current control and real-time fault protection, preventing motor damage due to overcurrent.

[0036] Furthermore, the shift controller integrates an LED driver circuit, which connects the P button and the shift knob's illumination via hard wiring. This allows for control of the button lights and gear indicator lights' brightness, providing clear status feedback to the driver. Its communication interface integrates a CAN FD communication controller and transceiver, supporting a data transmission rate of up to 2Mbps to meet the vehicle's high-speed communication requirements. It also supports the UDS protocol (Unified Diagnostic Services), enabling diagnostic functions such as fault code reading and data stream reading. Additionally, it supports the Boot Loader protocol, allowing for online software upgrades via the CAN bus, reducing after-sales maintenance costs. The shift controller's I / O control port is hard-wired to the relay module's control terminal, incorporating pull-up resistors and anti-bounce circuitry to effectively prevent relay malfunctions caused by electromagnetic interference, ensuring reliable control switching.

[0037] During implementation, the relay module serves as the core execution unit for control switching. Its single-pole double-throw (SPDT) relay module contains two identical SPDT relays, corresponding to the control circuits of the left and right drive motors of the EPB caliper, respectively. This ensures synchronous switching of control between the left and right calipers, preventing parking instability caused by abnormal control of one caliper. The common terminal of the SPDT relay module is hard-wired to the drive motor of the EPB caliper. The normally closed terminal is hard-wired to the motor drive output of the IPB controller, and the normally open terminal is hard-wired to the motor drive output of the shifter controller. The coil control terminal is hard-wired to the I / O control port of the shifter controller. When the relay coil is de-energized, the common terminal remains connected to the normally closed terminal and disconnected from the normally open terminal. At this time, the first hard-wire is connected to the drive motor of the EPB caliper, the second hard-wire is disconnected, and the IPB controller can perform normal control of the EPB caliper through the first hard-wire. When the relay coil is energized, the common terminal is disconnected from the normally closed terminal and connected to the normally open terminal. At this time, the second hard wire is connected to the drive motor of the EPB caliper, and the first hard wire is disconnected. The shift controller can perform backup control on the EPB caliper through the second hard wire. This relay module uses an automotive-grade sealed relay with a rated contact current of not less than 30A and an operating temperature range of -40℃ to 125℃, which can adapt to the complex temperature, humidity, and vibration environment inside the vehicle. The coil circuit has a built-in freewheeling diode, which can effectively suppress the back electromotive force generated when the coil is switched on and off, and avoid damage to the I / O port of the shift controller.

[0038] The EPB caliper employs a floating caliper disc structure, mounted on each of the vehicle's two rear wheels. Each caliper integrates a DC brushed drive motor, a reduction gear mechanism, a lead screw and nut mechanism, a brake piston, brake pads, a brake disc, a position sensor, and a current sampling circuit, serving as the core actuator for the parking brake. When the drive motor receives a clamping control command, it rotates forward, converting high-speed, low-torque output to low-speed, high-torque output via the reduction gear mechanism. This rotational motion is then converted to linear motion via the lead screw and nut mechanism, pushing the brake piston forward and causing the brake pads to press against the brake disc, generating braking force and achieving parking brake operation. When a release control command is received, the motor rotates in reverse, driving the brake piston backward via the reduction gear mechanism and lead screw and nut mechanism, separating the brake pads from the brake disc and releasing the parking brake. The EPB caliper's built-in position sensor is a Hall-effect linear position sensor, capable of real-time acquisition of the brake piston displacement signal with a displacement detection accuracy of up to 0.05mm, providing position feedback for precise clamping force control.

[0039] To achieve integrated configuration, the vehicle speed detection module is integrated into the vehicle's Electronic Stability Control (ESC) system. It collects real-time wheel speed signals through wheel speed sensors on all four wheels. These sensors, employing either magnetoelectric or Hall effect sensors, are mounted on the hub unit of each wheel, with a signal acquisition frequency of at least 100Hz and a speed detection accuracy of 0.1 km / h. The module incorporates a signal filtering algorithm to effectively filter signal fluctuations caused by wheel slippage, road bumps, and electromagnetic interference, ensuring a stable and accurate output speed signal. This provides crucial data support for determining safe parking conditions. As an optimization, the P button uses a self-resetting automotive-grade push-button switch, installed on the electronic shifter's handle or shift panel for easy driver operation. Its signal output is hard-wired to the shifter controller's ADC circuit. The button circuit incorporates pull-up resistors and filtering capacitors to effectively suppress electromagnetic interference and prevent accidental button triggering. Simultaneously, the P button includes an LED indicator, hard-wired to the shifter controller's LED driver circuit. The shifter controller controls the indicator's on / off state and flashing based on the EPB's operating status, providing the driver with intuitive feedback on the parking status.

[0040] The overall execution flow of the control method of the present invention consists of six steps, and the specific implementation steps are as follows: Step 1: System Power-On Self-Test and Mode Initialization. After the vehicle power is switched to the ON position, the IPB controller and the shifter controller power on and start simultaneously. After the core microprocessors of the two controllers complete reset, clock configuration, peripheral initialization, and memory initialization, they immediately start the self-test process. The self-tests of the two controllers are executed in parallel, and the self-test content includes motor drive circuit detection, sensor circuit detection, communication interface detection, and power circuit detection. Specifically, the motor drive circuit detection is implemented as follows: the controller sends a preset test drive signal to the motor drive circuit and simultaneously collects the current feedback signal and voltage feedback signal of the drive circuit. By comparing the feedback signal with the preset normal range, it determines whether there are faults such as open circuit, short circuit, or damaged drive chip in the motor drive circuit. For sensor circuit detection, the controller collects the output signals of each sensor, determines whether the signal is within the normal operating range, and simultaneously determines whether there are faults such as open circuit, short circuit, or abnormal signal in the sensors through cross-comparison of multiple signals. Communication interface detection involves the controller sending a preset test message to the CAN bus and simultaneously listening for the bus's response signal. This determines whether the CAN communication interface is functioning correctly, whether there are open circuits, short circuits, or missing terminating resistors on the bus, and whether the CAN bus's communication baud rate and sampling point configuration match the vehicle's overall bus configuration. Power circuit detection involves the controller acquiring the voltage values ​​of each internal power rail to determine if the voltage is within the normal operating range. It also detects whether there are overvoltage, undervoltage, overcurrent, or overheating faults in the power circuit.

[0041] After passing the self-test, both the IPB controller and the shifter controller send a normal self-test signal to the instrument panel via the CAN bus. The self-test process for both controllers is completed within 200ms, ensuring the vehicle can quickly enter a ready state after power-on. If both controllers pass their self-tests, the system completes initialization and enters normal mode. If either controller fails its self-test, the corresponding fault code is recorded and sent to the instrument panel, simultaneously entering fault handling mode.

[0042] The specific execution steps of the fault handling mode are as follows: If the self-test failure item is a recoverable fault, including non-hardware damage faults such as temporary CAN bus communication abnormalities, temporary sensor signal fluctuations, and temporary power supply voltage undervoltage, then the fault recovery process is executed, including re-initializing the communication interface, re-acquiring sensor signals, and restarting the power module. This fault recovery process can be repeated up to 3 times. If the self-test still fails after 3 recovery attempts, it is determined to be an unrecoverable fault. If the self-test failure item is an unrecoverable fault, including hardware failure faults such as motor drive circuit damage, sensor hardware damage, controller core microprocessor failure, and power circuit hardware damage, then vehicle gear shifting operations are restricted, the driver is prohibited from moving the gear lever out of P gear, and the corresponding fault prompt and fault code are displayed on the instrument panel to remind the driver to repair in time.

[0043] Step 2: Parking control and status monitoring in normal mode. After the system enters normal mode, the relay module is de-energized. The first hard wire remains connected to the drive motor of the EPB caliper, while the second hard wire remains disconnected. Control of the EPB caliper is entirely vested in the IPB controller. The shifter controller does not output any EPB drive signals, but only performs gear position recognition and IPB controller status monitoring functions.

[0044] In normal mode, the IPB controller, based on the driver's operating commands and the vehicle's real-time status, controls the EPB caliper to perform parking clamping or releasing control via a first hardwired connection: when the driver presses the P button, the vehicle is engaged in P gear and the vehicle speed is below a preset threshold, or the vehicle is turned off, the IPB controller controls the EPB caliper to perform a clamping action, achieving parking braking. When the driver depresses the brake pedal, engages D or R gear, or depresses the accelerator pedal, the IPB controller controls the EPB caliper to perform a releasing action, releasing the parking brake. When performing EPB control, the IPB controller employs a dual closed-loop control strategy of current closed-loop and position closed-loop. By real-time acquisition of the motor's operating current and the caliper piston position signal, it adjusts the PWM duty cycle of the drive signal to ensure precise clamping force and reasonable release stroke.

[0045] In normal mode, the core functions of the shifter controller are gear position recognition and IPB controller status monitoring. The process is as follows: The gear position detection module identifies the driver's gear shifting operations in real time and sends the gear position status signal via the CAN bus to the IPB controller and other vehicle controllers, providing gear position information for the vehicle's powertrain and braking systems. Simultaneously, it continuously monitors the 10ms periodic heartbeat status signal (0x204 signal) sent by the IPB controller via the CAN bus, as well as the backup request signal (0x205 signal) sent by the IPB controller. During implementation, the shifter controller monitors the heartbeat status signal by acquiring it every 10ms on the CAN bus. If no valid heartbeat status signal is acquired in 50 consecutive acquisitions, it is determined that no heartbeat status signal has been received for 50 consecutive cycles. The logic for determining the validity of a heartbeat status signal is as follows: the received message ID is completely consistent with the preset 0x204 signal ID, the CRC check (CRC Cyclic Redundancy Check) of the message passes and there are no transmission errors, and the signal value in the message is within the preset normal range and there are no invalid or abnormal values. Only when all three conditions are met simultaneously can a valid heartbeat status signal be determined to have been received.

[0046] Meanwhile, the shift controller continuously monitors the backup request signal 0x205 sent by the IPB controller. If it receives a message indicating that the backup takeover request flag is set, it determines that a backup request signal has been received. In addition, the shift controller will send the monitored IPB controller status, its own operating status, and gear status to the vehicle's instrument panel via the CAN bus in real time, providing the driver with a clear status display. At the same time, it continuously executes its own fault diagnosis logic, and monitors the operating status of hardware circuits, sensors, and communication interfaces in real time to ensure that it can perform backup takeover functions at any time.

[0047] Step 3: Backup Takeover Trigger Condition Judgment and Safety Condition Verification. When the shift controller detects that it has not received a valid heartbeat status signal for 50 consecutive cycles, or receives a backup request signal from the IPB controller, it immediately triggers the backup takeover process. After triggering, it does not immediately perform a switchover; instead, it first verifies the backup takeover safety conditions through the vehicle speed detection module and gear position detection module to avoid performing a switchover operation under unsafe conditions and ensure vehicle safety. Specifically, if no valid heartbeat status signal is received for 50 consecutive cycles, corresponding to 500ms without a signal (the heartbeat signal transmission cycle is 10ms), it is determined that the IPB controller has experienced a CAN communication failure and cannot continue to execute the EPB control function. When a backup request signal is received and the backup takeover request flag is set, it is determined that the IPB controller has detected an internal fault and cannot continue to execute the EPB control function, actively requesting the shift controller to take over. The backup takeover safety conditions are: the real-time vehicle speed collected by the vehicle speed detection module is less than 3km / h, and the vehicle gear collected by the gear position detection module is P gear. The safety condition verification logic is as follows: The shifter controller continuously collects vehicle speed signals three times via the CAN bus. If all three vehicle speed values ​​are less than 3 km / h, the vehicle speed condition is deemed met. The position sensor and current acquisition signals confirm that the EPB caliper is in a fully clamped and stable state, with no clamping force decay or piston displacement change. If so, the caliper state condition is deemed met. Only when both conditions are met simultaneously is the backup takeover safety condition verification considered successful.

[0048] Furthermore, if the backup takeover safety condition verification fails, the shift controller will not perform the control switch operation and will continue to monitor the vehicle status. Simultaneously, it will send a fault warning signal to the vehicle's instrument panel via the CAN bus. This alerts the driver that the IPB controller has malfunctioned and that the vehicle should be moved to a safe area as soon as possible. Engaging the P gear will automatically activate the backup mode. If the safety condition verification passes, the subsequent relay control switch operation will be executed immediately, entering backup mode. During the safety condition verification process, the shift controller continuously monitors the IPB controller's status. If the IPB controller recovers and resends a valid heartbeat status signal, the backup takeover process will terminate, and the normal mode will remain unchanged.

[0049] Step 4: Relay Control Switching and Backup Mode Activation. After the backup takeover safety condition verification is passed, the shifter controller first stops responding to any parking control commands sent by the IPB controller, and simultaneously switches its own operating state to the backup takeover ready state to avoid control logic conflicts. Then, it executes the relay control switching operation. Specifically, the shifter controller outputs a high-level signal to the coil control terminal of the relay module through the I / O port, energizing the relay coil. After the coil is energized, the relay's common terminal disconnects from the normally closed terminal and connects to the normally open terminal. This disconnects the first hard wire from the EPB caliper drive motor and connects the second hard wire to the EPB caliper drive motor. Since the relay module's switching action execution time is no more than 20ms, the shifter controller delays for 30ms after outputting the high-level signal to ensure the relay completes a stable state switch and avoids abnormal drive signal output caused by incomplete contact stabilization.

[0050] After the relay switching is completed, the shift controller performs a drive circuit continuity test. By outputting a small test current to the H-bridge drive circuit, it collects the current feedback signal of the circuit to determine whether the second hardwire and the EPB caliper drive motor are fully connected, ensuring a successful control switch. If the continuity test fails, the shift controller will re-execute the relay switching operation, repeating it up to 3 times. If it still fails to connect after 3 switches, it is determined to be a relay hardware failure, the corresponding fault code is recorded, and a fault warning signal is sent to the vehicle's instrument panel. If the continuity test passes, it officially enters backup mode and sends a backup mode activation warning signal to the instrument panel via the CAN bus.

[0051] The backup mode activation prompt signal will display corresponding text and icon prompts on the vehicle's instrument panel, informing the driver that the IPB controller has malfunctioned and the system has activated EPB backup mode, allowing normal execution of the parking brake function. Once in backup mode, the shift controller completely takes over the control of the EPB caliper. No drive signals from the IPB controller can be transmitted to the EPB caliper's drive motor via the first hardwire, ensuring the uniqueness of the control logic at the hardware level and preventing hardware damage caused by conflicts between the two control signals.

[0052] Step 5: EPB Control and IPB Status Monitoring in Backup Mode. Upon entering backup mode, the shifter controller performs clamping and releasing control on the EPB caliper via a second hardwired connection. Simultaneously, it continuously monitors the 0x203 self-test pass signal sent by the IPB controller to confirm the IPB controller's recovery status, ensuring timely return of control once the IPB controller returns to normal. In backup mode, the shifter controller performs clamping control on the EPB caliper in the following steps: Step A: When the vehicle is detected to be in P gear or the driver triggers the P button, the drive motor of the EPB caliper is started with a maximum current of 20A for 30-100ms to overcome static friction, preferably 50ms. During implementation, the maximum current can be selected from 18A to 22A, and the duration can be selected from 30ms to 70ms, which can be adapted and adjusted according to the load characteristics of the EPB calipers of different vehicle models; Step B, the PWM duty cycle is adjusted by the PID algorithm to stabilize the working current of the drive motor within the range of 17A±1A, and uniform clamping action is performed. During implementation, the working current can be selected from 16A to 18A, which can be adjusted according to the parking clamping force required by different vehicle models. The discrete formula of the PID algorithm is u(k)=Kp e(k)+Ki Σe(j)+Kd [e(k)-e(k-1)], where u(k) is the PWM output value of the kth sample, Kp is the proportional coefficient, Ki is the integral coefficient, Kd is the differential coefficient, e(k) is the current deviation value of the kth sample, and e(k-1) is the current deviation value of the (k-1)th sample. In step C, maintain a 17A operating current for 500ms. After establishing the target clamping force, switch to the 1A low-current holding mode. Simultaneously, illuminate the indicator light on the P button to indicate the parking completion status. During implementation, the current holding time can be selected within the range of 400ms to 600ms, and the holding current can be selected within the range of 0.8A to 1.2A, which can be adjusted according to the caliper's transmission characteristics.

[0053] Throughout the clamping process, the shifter controller samples the motor's operating current every 10ms. If the current exceeds the upper limit of 17A for 10 consecutive samples (i.e., within 100ms), a mechanical jamming fault is identified, the clamping action is immediately stopped, and the corresponding fault code DTC_C121 is recorded. Simultaneously, a fault warning signal is sent to the vehicle's instrument panel via the CAN bus. After the clamping action is completed, the shifter controller collects the brake piston position signal through the position sensor to confirm that the caliper is fully clamped. At the same time, the indicator light on the P button is illuminated, and an EPB clamping completion status signal is sent to the vehicle's instrument panel via the CAN bus to provide feedback to the driver.

[0054] In backup mode, the shift controller performs the following steps for releasing the EPB caliper: Step A: When the vehicle is detected to have moved out of P gear or the driver has triggered the P button release operation, the drive motor of the EPB caliper is controlled to rotate in the reverse direction, quickly releasing a safety distance of 0.7-1.5mm, with a time not exceeding 200ms. During implementation, the safety distance can be selected within the range of 0.7mm to 1.2mm, and the rapid release time can be selected within the range of 150ms to 250ms, which can be adapted and adjusted according to the caliper characteristics of different vehicle models. Step B: The speed of the drive motor is reduced to perform a slow release action, with a total release time not exceeding 1.5s. During implementation, the total release time can be selected within the range of 1s to 2s, which can be adjusted according to the NVH requirements of the entire vehicle. Step C: During the release process, monitor the operating current of the drive motor in real time. If the instantaneous current exceeds 16A or the current is sampled once every 150ms and the average current value after taking 3 samples exceeds 10A, the release action will be stopped immediately, the corresponding fault code will be recorded and sent to the instrument panel. During implementation, the instantaneous current threshold can be selected from 17A to 19A, and the average current threshold can be selected from 8A to 11A. It can be adjusted according to the motor characteristics of different vehicle models.

[0055] It should be noted that before the release control is triggered, the shift controller will first verify the release safety conditions. The EPB release control process will only be triggered when the driver presses the brake pedal and the vehicle speed is 0, in order to avoid the risk of the vehicle rolling away. After the release action is completed, the shift controller collects the position signal of the brake piston through the position sensor to confirm that the caliper has been fully released. At the same time, it turns off the indicator light of the P button and sends the EPB release completion status signal to the vehicle's instrument panel through the CAN bus.

[0056] In backup mode, the shift controller also performs linkage control between gear position and EPB: when the vehicle is detected to be in P gear and the real-time vehicle speed is less than 3km / h, the EPB caliper clamping control is automatically triggered; when the vehicle is detected to be out of P gear, the EPB caliper release control is automatically triggered. The execution priority of linkage control is lower than the driver's manual operation command. If the driver manually presses the P button to trigger the parking or release command, the system will prioritize the driver's manual command, improving the flexibility and safety of operation.

[0057] Meanwhile, the shifter controller continuously monitors the self-test pass signal 0x203 sent by the IPB controller to confirm the IPB controller's recovery status. The monitoring method involves continuously acquiring the self-test pass signal sent by the IPB controller on the CAN bus. If a valid self-test pass signal is received for three consecutive cycles, the IPB controller is considered to have recovered normally. The validity judgment logic for the self-test pass signal is as follows: the message ID is completely consistent with the preset 0x203 signal ID; the message's CRC check passes and there are no transmission errors; the self-test result flag in the message shows a self-test pass and there is no fault indication. Only when all three conditions are met is a valid self-test pass signal received. If the IPB controller is determined to have recovered normally, the shifter controller will immediately initiate the control handover process, verify the safety conditions for handing over control, and prepare to hand over control of the EPB caliper to the IPB controller, restoring normal mode. If the IPB controller is not detected to have recovered normally, the shifter controller will continue to maintain backup mode, stably executing the EPB control function to ensure parking safety.

[0058] Step Six: Control Transfer and Mode Recovery. When the shift controller detects that the IPB controller has returned to normal and verifies that the safety conditions for transferring control have been met, it controls the relay module to switch via the I / O port, connecting the first hardwire and disconnecting the second hardwire, thus transferring control of the EPB caliper back to the IPB controller. The system returns to normal mode, forming a closed-loop control.

[0059] After the shift controller determines that the IPB controller has returned to normal, it will not immediately perform the control handover operation. Instead, it will first verify the safety conditions for handing over control. These safety conditions are: the real-time vehicle speed collected by the vehicle speed detection module is less than 3 km / h, and the EPB caliper is in a stable clamping state. The verification logic for the safety conditions is as follows: the shift controller continuously collects the vehicle speed signal three times via the CAN bus. If all three vehicle speed values ​​are less than 3 km / h, the vehicle speed condition is considered met. The position sensor and current collection signals are used to confirm that the EPB caliper is in a stable, fully clamped state with no clamping force decay or piston displacement change. If so, the caliper state condition is considered met. Only when both conditions are met simultaneously is the verification of the safety conditions for handing over control considered successful.

[0060] If the safety condition verification for handing over control fails, the shift controller will not perform the control handover operation, maintaining backup mode and continuously monitoring the vehicle status until the safety conditions are met before performing the handover operation. If the safety condition verification passes, the shift controller first stops outputting any EPB drive signals and simultaneously outputs a low-level signal to the coil control terminal of the relay module via the I / O port, de-energizing the relay coil. After the coil is de-energized, the relay common terminal disconnects from the normally open terminal and reconnects to the normally closed terminal, disconnecting the second hard wire from the EPB caliper drive motor and reconnecting the first hard wire to the EPB caliper drive motor. After the relay switching action is completed, the shift controller will delay for 30ms to ensure the relay contacts are fully stable, and simultaneously send a control handover completion signal to the IPB controller via the CAN bus, informing the IPB controller that control of the EPB caliper has been restored. After control is transferred back, the system returns to normal mode, and the IPB controller regains control of the EPB caliper. The shift controller resumes its normal mode status monitoring and gear position recognition functions, and simultaneously sends a backup mode deactivation signal to the vehicle's instrument panel via the CAN bus, canceling the fault indication on the instrument panel and informing the driver that the system has returned to normal operation. After control is transferred back, the shift controller will restart continuous monitoring of the IPB controller's heartbeat status signal. If an IPB controller malfunction or loss of connection is detected again, the backup takeover process will be triggered again to ensure that the parking function is always in a reliable state.

[0061] The following three typical examples illustrate the use of the technology in common scenarios.

[0062] Example 1: Backup takeover in the scenario of IPB communication failure.

[0063] During normal vehicle operation, the system is in normal mode, the relay module is de-energized, and the IPB controller is connected to the EPB caliper via the first hardwire to perform normal parking control functions. The shift controller continuously monitors the 10ms heartbeat status signal sent by the IPB controller. If the IPB controller's CAN communication interface malfunctions and stops sending heartbeat status signals, and the shift controller does not receive a valid heartbeat status signal for 500ms (i.e., no signal for 50 consecutive cycles), it immediately triggers the backup takeover process.

[0064] At this point, the driver has parked the vehicle in a safe area and engaged P gear. The real-time vehicle speed detected by the speed detection module is 0 km / h, and the gear position detection module identifies P gear as the correct position. The backup takeover safety conditions have been verified. The shift controller outputs a high-level signal to the relay module via the I / O port, energizing the relay coil, disconnecting the first hard wire, and connecting the second hard wire, completing the control switch. It then enters backup mode and simultaneously sends a backup mode activation prompt signal to the vehicle's instrument panel via the CAN bus. The instrument panel displays the message "EPB system fault, backup mode activated," and the EPB fault light remains solid yellow.

[0065] When the driver presses the P button, the shift controller receives the operation command and executes the EPB clamping control process: the control motor starts with a maximum current of 20A for 50ms to overcome static friction, then the current is stabilized at 17A using a PID algorithm and maintained for 500ms to build sufficient clamping force. Afterward, it switches to a low-current holding mode of 1A, while the P button indicator light illuminates, and the instrument panel displays the parking completed status. When the driver depresses the brake pedal and moves the gear lever out of P, the shift controller detects the gear shift and automatically executes the EPB release control process: first, a rapid release of 0.9mm safety distance, followed by a slow release, with a total release time of 1.2s. After release, the P button indicator light turns off, and the instrument panel displays the parking released status.

[0066] After the vehicle is turned off and the driver turns the power back on, the CAN communication fault of the IPB controller is resolved, and a valid self-test pass signal is resent. The shift controller receives valid self-test pass signals for three consecutive cycles, determining that the IPB controller has returned to normal. Subsequently, the safety conditions for returning control are verified. At this point, the vehicle is stationary at 0 km / h, and the EPB caliper is in a stable clamping state; the safety condition verification is successful. The shift controller outputs a low-level signal to the relay module through the I / O port, de-energizing the relay coil, reconnecting the first hard wire, and disconnecting the second hard wire, returning control to the IPB controller. The system returns to normal mode, the fault indicator on the instrument panel disappears, and the system resumes normal operation.

[0067] Example 2: Corresponding to the scenario where IPB actively requests backup takeover.

[0068] After the vehicle power supply is switched to the ON position, the IPB controller and the shift controller are powered on simultaneously and execute a self-test process. The shift controller passes all self-tests, but the IPB controller detects a fault in its own H-bridge drive circuit, which cannot output drive current normally, and its self-test fails. Subsequently, the IPB controller sends a backup request signal to the shift controller via the CAN bus, sets the backup takeover request flag, and sends fault type information.

[0069] Upon receiving the backup request signal, the shift controller immediately triggers the backup takeover process, verifying the backup takeover safety conditions. At this time, the vehicle is stationary, the speed is 0 km / h, and the gear is in P (Park). The safety condition verification is successful. The shift controller controls the relay module to switch via the I / O port, disconnecting the first hard wire and connecting the second hard wire, entering backup mode. Simultaneously, it sends backup mode activation and fault indication signals to the instrument panel.

[0070] After entering backup mode, the shift controller completely takes over the control functions of the EPB caliper. The driver can use the P button to switch gears and normally perform parking clamping and releasing actions, ensuring the vehicle can be driven and parked normally. After the vehicle was brought in for repair, the repair personnel replaced the faulty IPB controller. After powering on again, the new IPB controller passed its self-test and sent a valid self-test pass signal. The shift controller detected that the IPB controller had returned to normal. After verifying that the safety conditions for returning control had passed, it executed the control return operation, and the system returned to normal mode.

[0071] Example 3: Fault detection scenario in backup mode. The system is in backup mode, the EPB caliper is fully released, the vehicle is parked on a slope, and after the driver shifts into P gear, the shift controller automatically triggers the EPB clamping control process: the motor is controlled to start with a maximum current of 20A for 50ms to overcome static friction, and then the PWM duty cycle is adjusted through the PID algorithm to try to stabilize the motor current at 17A.

[0072] During clamping, a foreign object became stuck inside the EPB caliper, causing the motor to stall and the operating current to rise rapidly. The shifter controller sampled the motor current every 10ms, and the current value collected for 10 consecutive times exceeded 17A, indicating a mechanical jamming fault. Subsequently, the shifter controller immediately stopped the motor drive output, terminated the clamping action, recorded fault code DTC_C121 (mechanical jamming fault), and simultaneously sent a fault warning signal to the instrument panel via the CAN bus. The EPB fault light on the instrument panel flashed red, indicating to the driver that the caliper had malfunctioned.

[0073] Afterwards, the shifter controller executes the fault recovery procedure, controlling the motor to rotate in reverse to perform a release action, attempting to disengage the stuck state. Once released, the clamping action is re-executed. If the stuck fault is resolved, the clamping operation is completed normally. If the stuck fault persists, the fault state is maintained, restricting vehicle shifting operations and continuously sending fault warnings to the driver, reminding them to repair the vehicle promptly.

[0074] The system provided by this invention adopts the CAN FD communication protocol, supports a maximum data transmission rate of 2Mbps, which can meet the high-speed communication requirements of the entire vehicle and ensure efficient and stable data interaction between various controllers. The system supports UDS diagnostic services including fault code reading, fault code clearing, data stream reading, action testing, secure access, routine control, data download, and version information reading. After-sales diagnostic equipment can connect to the vehicle's CAN bus via the OBD diagnostic interface to perform diagnostic communication with the IPB controller and shift controller, facilitating after-sales maintenance and troubleshooting. Simultaneously, the system supports the OSEK NM / AUTOSAR NM network management protocol, enabling network sleep and wake-up management of the vehicle controller. When the vehicle is turned off, the system enters sleep mode, shutting down unnecessary peripheral circuits and reducing static power consumption. When the system detects driver operation of the door, ignition switch, or P button, it immediately wakes up and enters normal operating mode, balancing energy saving and response speed.

[0075] All signals transmitted via the CAN bus employ a dual verification mechanism of rolling counter and CRC check. The receiver verifies the rolling counter and CRC check value of the message, and only messages that pass the verification are considered valid. This effectively avoids interference and misjudgment during signal transmission and improves communication reliability.

[0076] The system has a built-in full-cycle fault diagnosis mechanism. Real-time fault diagnosis is performed during the power-on self-test phase, normal mode operation phase, backup mode operation phase, and control switching phase. The fault diagnosis scope covers hardware faults, software faults, communication faults, and actuator faults, enabling rapid identification, recording, and feedback of faults.

[0077] Based on the severity of the fault, the system classifies faults into four levels and executes corresponding handling strategies for each level: Level 1 faults are minor faults, including temporary fluctuations in sensor signals, temporary CAN bus communication interference, and slight fluctuations in power supply voltage. The system will record the corresponding fault code, which will not affect normal functions, and will execute an automatic recovery process. Level 2 faults are moderate faults, including single Hall sensor failure, slight poor contact of the P button, and indicator light drive circuit failure. The system will record the fault code, send a maintenance reminder to the driver through the instrument panel, and activate the redundancy fault tolerance mechanism to ensure that core functions are not affected. Level 3 faults are serious faults, including IPB controller failure, continuous loss of CAN communication, and partial failure of the motor drive circuit. The system will trigger a backup takeover process, with the shifter controller taking over the EPB control function to ensure the parking function is normal and available, and will send a fault warning. Level 4 faults are fatal faults, including simultaneous failure of the IPB controller and shifter controller, hardware damage to the relay module, and simultaneous failure of both sides of the EPB caliper. The system will immediately restrict vehicle shifting operations, prohibit vehicle movement, and issue a strong fault alarm through the instrument panel to maximize the safety of the vehicle and its occupants.

[0078] Furthermore, the orientations or positional relationships described in this invention are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the purpose of facilitating the description of this invention and simplifying the description, and are not intended to indicate or imply that the device or structure referred to must have a specific orientation, or to operate in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0079] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A control method for an automotive electronic gear shifter integrating electronic parking brake function, characterized in that: This system, implemented using an IPB controller, a shifter controller, a CAN bus, a relay module, an EPB caliper, a vehicle speed detection module, a gear position detection module, and a P button, is as follows: The IPB controller is connected to the drive motor of the EPB caliper via a first hardwire through the normally closed terminal of the relay module, and is connected to the shifter controller via the CAN bus. The shifter controller is connected to the drive motor of the EPB caliper via a second hardwire through the relay module, and is connected to the IPB controller, the vehicle speed detection module, and the gear position detection module via the CAN bus, and is also connected to the P button via a hardwire. The relay module is connected to both the first and second hardwires. The shifter controller controls the switching of the hardwires via I / O ports, ensuring that only one of the first or second hardwires is connected to the drive motor of the EPB caliper at any given time. This includes the following steps: Step 1: After the system is powered on, the IPB controller self-test and the shifter controller self-test are performed in parallel. If both self-tests pass, the system enters normal mode. If either self-test fails, the system enters fault handling mode. Step 2: In normal mode, the IPB controller performs parking control on the EPB caliper through the first hardwire. At the same time, the shifter controller continuously monitors the heartbeat status signal with a period of 10ms sent by the IPB controller via the CAN bus, as well as the backup request signal sent by the IPB controller. Step 3: When the shift controller detects that it has not received a heartbeat status signal for several consecutive cycles or has received the backup request signal, it triggers the backup takeover process and verifies the backup takeover safety conditions through the vehicle speed detection module and the gear detection module. Step 4: If the backup takeover security condition verification is successful, the shifter controller controls the relay module to disconnect the first hard wire and connect the second hard wire through the I / O port to enter the backup mode; Step 5: In backup mode, the shifter controller performs clamping or releasing control on the EPB caliper via the second hardwire, while continuously monitoring the self-test pass signal sent by the IPB controller to confirm the recovery status of the IPB controller. Step six: When the shift controller detects that the IPB controller has returned to normal and the safety conditions for returning control have been verified, it controls the relay module to connect the first hardwire and disconnect the second hardwire through the I / O port, returns control to the IPB controller, and returns to the normal mode.

2. The automotive electronic gear shifter control method integrating electronic parking brake function according to claim 1, characterized in that: In step one, the self-test of the IPB controller and the self-test of the shifter controller both include motor drive circuit detection, sensor circuit detection, communication interface detection, and power circuit detection. After the self-test passes, both the IPB controller and the shifter controller send a normal self-test signal to the instrument panel via the CAN bus. If the self-test fails, the IPB controller records the corresponding fault code and sends it to the instrument panel.

3. The automotive electronic gear shifter control method integrating electronic parking brake function according to claim 1, characterized in that: In step one, the execution steps of the fault handling mode are as follows: if the self-test failure item is a recoverable fault, then the fault recovery process is executed, and after successful recovery, the normal mode is entered; if the self-test failure item is an unrecoverable fault, then the vehicle's gear shifting operation is restricted and a fault prompt is sent to the instrument panel.

4. The automotive electronic gear shifter control method integrating electronic parking brake function according to claim 1, characterized in that: In step two, the shifter controller monitors the heartbeat status signal by acquiring the heartbeat status signal on the CAN bus every 10ms. If no valid heartbeat status signal is acquired in 50 consecutive acquisitions, it is determined that the heartbeat status signal has not been received for 50 consecutive cycles.

5. The automotive electronic gear shifter control method integrating electronic parking brake function according to claim 1, characterized in that: In step three, the backup takeover safety conditions are: the real-time vehicle speed corresponding to the vehicle speed signal collected by the vehicle speed detection module is less than 3km / h, and the vehicle gear corresponding to the gear signal collected by the gear detection module is P gear.

6. The automotive electronic gear shifter control method integrating electronic parking brake function according to claim 1, characterized in that: In step four, while the gear shifter controller controls the relay module to switch, it sends a backup mode activation prompt signal to the instrument panel via the CAN bus.

7. The automotive electronic gear shifter control method integrating electronic parking brake function according to claim 1, characterized in that: In step five, the step of the shifter controller performing clamping control on the EPB caliper in backup mode is as follows: Step A: When the vehicle is detected to be in P gear or the driver triggers the P button, the shift controller controls the drive motor of the EPB caliper to start with maximum current for 30-100ms to overcome static friction. Step B: Adjust the PWM duty cycle using the PID algorithm to stabilize the operating current of the drive motor within the range of 17A±1A, and perform uniform clamping action. Step C: Maintain a working current of 17A for 500ms to establish the target clamping force, then switch to a low current holding mode of 1A, and simultaneously illuminate the indicator light of the P button to indicate that the parking is complete.

8. The automotive electronic gear shifter control method integrating electronic parking brake function according to claim 1, characterized in that: In step five, in backup mode, the step of the shifter controller performing release control on the EPB caliper is as follows: Step A: When the vehicle is detected to have moved out of P gear or the driver has triggered the P button to release the gear, the drive motor of the EPB caliper is controlled to rotate in the opposite direction to quickly release a safety distance of 0.7-1.5mm, with a time of no more than 200ms. Step B: The shifter controller reduces the speed of the drive motor to perform a slow release action, with a total release time not exceeding 1.5 seconds; Step C: During the release process of the shifter controller, the operating current of the drive motor is monitored in real time. If the instantaneous current exceeds 16A, or if the current is sampled once every 150ms and the average current value after taking 3 samples exceeds 10A, the release action is stopped immediately, the corresponding fault code is recorded and sent to the instrument panel.

9. The automotive electronic gear shifter control method integrating electronic parking brake function according to claim 1, characterized in that: In step five, in backup mode, the shifter controller performs the linkage control between gear position and EPB as follows: when the vehicle is detected to be in P gear and the real-time vehicle speed is less than 3km / h, the clamping control of the EPB caliper is automatically triggered; when the vehicle is detected to be out of P gear, the release control of the EPB caliper is automatically triggered.

10. The automotive electronic gear shifter control method integrating electronic parking brake function according to claim 1, characterized in that: In step six, the safety conditions for handing over control are: the real-time vehicle speed corresponding to the vehicle speed signal collected by the vehicle speed detection module is less than 3 km / h, and the EPB caliper is in a stable clamping state.

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