Windscreen wiper control system

Abstract

The invention discloses a windscreen wiper control system which comprises a signal and sensor input module, an MCU processing module, a motor pre-driving module and a motor power driving module. Windscreen wiper control command signals from a driver are received, and meanwhile position information of a windscreen wiper is calculated based on an angle sensor; the MCU processing unit carries out calculation and decision making on the motion requirement of the windscreen wiper, then the motion requirement is converted into an electric control signal to be sent to the motor pre-driving module, the motor power driving module further completes operation driving on a windscreen wiper motor, finally the windscreen wiper motor drives a wiper arm and a wiper blade to move, and the wiping function of a front windshield is achieved.

Description

Technical Field

[0001] This invention relates to the field of automotive electronic control, and discloses a windshield wiper control system for automobiles that meets functional safety requirements. Background Technology

[0002] Among the many actuators in a car, the windshield wiper plays a crucial role in driving in the rain. It is an essential feature of cars, used to wipe away rainwater, dust, and other debris from the windshield, thereby improving the driver's visibility and ensuring driving safety.

[0003] The electronic wiper control system is equipped with a dedicated electronic control module. This module receives wiper control commands from the driver via an onboard communication bus (such as LIN communication), and precisely regulates the operation of the wiper motor based on sensor signals or preset programs. This allows for diverse wiper blade movement modes and speed adjustments, resulting in a more intelligent and efficient wiping effect.

[0004] The electronic wiper control system is based on the input sensor signals, which are processed by the central processing unit and then output to control the wiper motor.

[0005] Due to the inherent characteristics of vehicle electronic control systems, risks exist throughout the entire control chain. Products may experience systemic and random failures, leading to corresponding safety risks. For example, if the central processing unit malfunctions or fails, the entire control system will malfunction, directly impacting vehicle safety and reliability. Other systems may experience command delays or distortions due to poor communication between modules or insufficient data processing capabilities. Furthermore, a lack of redundancy design means that backup support cannot be provided in the event of a failure, preventing the execution of critical functions and increasing the likelihood of accidents.

[0006] As an important safety-related system, the existing electronic windshield wiper control system may also fail due to deficiencies in functional safety design, resulting in system or random failures that prevent it from continuing to wipe the windshield normally and thus fail to provide the driver with effective visibility.

[0007] Furthermore, existing electronic wiper control systems use electronic control modules, which, under normal operating conditions, can perform basic wiper control based on the requirements of the main controller (body controller or domain controller, etc.). However, due to the lack of functional safety mechanisms, when a control system malfunction occurs, the wiper function may fail, and fault information cannot be promptly fed back to and alert the driver, thus reducing vehicle safety to some extent. Summary of the Invention

[0008] The technical problem to be solved by this invention is to address the aforementioned safety issues, namely that existing electronic wiper control systems cannot meet the requirements of ISO26262 automotive functional safety, and to provide a wiper control system that incorporates functional safety design elements to improve system reliability and robustness.

[0009] The technical problem to be solved by this invention can be achieved through the following technical solution: A wiper control system, comprising: The signal and sensor input module is connected to the body controller or domain controller for inputting power supply, wiper angle and ambient temperature signals. The MCU processing module has its signal input terminal connected to the signal output terminal of the signal and sensor input module. It is used to parse the control commands of the wiper system, manage the status of the wiper system, perform ADC control, calculate the wiper position, manage the power supply of the wiper control system, control the wiper motion, and perform diagnostic protection and safety monitoring of the wiper control system. A motor pre-drive module, wherein the signal input terminal of the motor pre-drive module is connected to the signal output terminal of the MCU processing module, for use in driving and controlling the wiper movement and providing feedback; The motor power drive module has its signal input terminal connected to the signal output terminal of the motor pre-drive module, and its signal output terminal connected to the wiper motor control for controlling the wiper motor drive and current feedback.

[0010] In a preferred embodiment of the present invention, the wiper control system diagnostic protection and safety monitoring of the MCU processing module adopts a layered modular functional safety architecture, wherein the layered modular functional safety architecture includes a hardware functional safety mechanism layer, a platform software functional safety mechanism layer, and an application software functional safety mechanism layer.

[0011] In a preferred embodiment of the present invention, the hardware functional safety mechanism layer includes redundant sensor input circuits, redundant vehicle interaction links, an independent watchdog module, and a fault diagnosis circuit.

[0012] In a preferred embodiment of the present invention, the platform software functional safety mechanism layer includes a system power-on self-test mechanism, a redundant ADC conversion verification mechanism, a communication end-to-end protection mechanism, and a driver fault diagnosis and protection mechanism.

[0013] In a preferred embodiment of the present invention, the application software functional safety mechanism layer includes a system operation monitoring mechanism, a limp control strategy mechanism, and a wiper movement monitoring mechanism.

[0014] By employing the above technical solutions, this invention, based on functional safety design and adopting a layered modular functional safety architecture, integrates multiple functional safety monitoring and diagnostic protection mechanisms. While ensuring the normal functioning of the electronic wiper control system, it can perform safety monitoring and diagnosis of the driver-input wiper control command signals, key sensor signals, power supply and MCU processing system, motor drive output, and other internal modules of the wiper control system. It can report wiper system faults to the upper-level controller via the bus when system anomalies occur. Simultaneously, it provides an auxiliary drive function when the electronic wiper control system fails, reducing the probability of complete loss of windshield wiper control function when the wiper system malfunctions, ensuring the wiper control system always operates in a safe and controllable state. This effectively improves the safety performance of the wiper system. Attached Figure Description

[0015] Figure 1 This is a structural block diagram of the electronic wiper control system of the present invention; Figure 2 This is a schematic diagram of the layered modular functional safety architecture of the electronic wiper control system of the present invention.

[0016] Figure 3 This invention provides a functional safety implementation method and control flowchart for the electronic wiper control system. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will now be described with reference to the accompanying drawings. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0018] like Figure 1 As shown in the figure, a wiper control system includes: The signal and sensor input module is connected to the body controller or domain controller for inputting power supply, wiper angle and ambient temperature signals. The MCU processing module has its signal input terminal connected to the signal output terminal of the signal and sensor input module. It is used to parse the control commands of the wiper system, manage the status of the wiper system, perform ADC control, calculate the wiper position, manage the power supply of the wiper control system, control the wiper motion, and perform diagnostic protection and safety monitoring of the wiper control system. A motor pre-drive module, wherein the signal input terminal of the motor pre-drive module is connected to the signal output terminal of the MCU processing module, for use in driving and controlling the wiper movement and providing feedback; The motor power drive module has its signal input terminal connected to the signal output terminal of the motor pre-drive module, and its signal output terminal connected to the wiper motor control for controlling the wiper motor drive and current feedback.

[0019] When the wiper system is functioning normally, it receives wiper control command signals from the driver and calculates the wiper position information based on the angle sensor. The MCU processing unit calculates and makes decisions on the wiper's movement requirements and then converts them into electrical control signals for the motor pre-drive module. The motor power drive module then drives the wiper motor to operate, and finally the wiper motor drives the wiper arm and wiper blade to move, thus realizing the wiping function of the windshield.

[0020] like Figure 2 As shown, the electronic wiper control system that meets functional safety requirements disclosed in this embodiment of the invention adopts a layered modular functional safety architecture, specifically divided into three layers: Level 1: Hardware Functional Safety Layer: This layer provides the hardware framework for ensuring the functional safety of the windshield wiper control system. The functional safety mechanisms included in this layer are: 1. Redundant sensor input circuit: The key angle sensor signal adopts dual-channel redundant signal output. Specific implementation of the invention: An angle sensor with SIN / COS dual signal inputs is used to achieve mutual verification between the two signals; 2. Redundant Vehicle Interaction Link: The command interaction between the vehicle and the wiper control system, based on the existing LIN (In-Vehicle Bus) communication, adds a redundant hardwire connection. Specific implementation of this invention: 1) Adding a redundant hardwire for an independent data communication channel; 2) This redundant hardwire is connected to both the vehicle's mechanical switch and the input terminal of the wiper control system. 3. Independent Watchdog Module: A built-in or external hardware watchdog module with an independent clock source (supporting timeout or window mechanism). Specific implementation of this invention: 1) Employs a hardware watchdog module with an independent clock source, unaffected by MCU system clock interference; 2) The watchdog module supports timed / window-based watchdog feeding mechanisms; 3) If the watchdog is reset more than a certain number of times consecutively, the entire system enters a safe sleep mode. 4. Other hardware fault diagnosis devices and circuits: Integrating hardware circuit modules for current sampling, voltage sampling, and temperature sampling required for system diagnosis. Specific implementations of the invention include: 1) providing sampling circuits for the power supply voltage and internal voltage of the wiper system; 2) providing a driving current sampling circuit for the motor drive module; and 3) providing a temperature sampling circuit for the wiper control system.

[0021] Level Two: Platform Software Functional Safety Layer: This layer provides general functional safety mechanisms for platform software modules. The functional safety mechanisms included in this layer are: 1. End-to-End Communication Protection: A rolling counter and a CRC check mechanism are used in the vehicle communication (LIN) messages to achieve end-to-end (E2E) protection for message transmission and reception. Specific implementation methods of this invention include: 1) Implementing end-to-end protection for specific important messages related to wiper control on the LIN bus; 2) Adding a 4-bit rolling counter signal to the message to cyclically count consecutive messages from 0 to 15, thereby verifying the reliability and validity of consecutive messages; 3) Adding an 8-bit check signal to the message to verify the validity of the entire message using a CRC algorithm. 2. Redundant ADC conversion verification; Specific implementation of the invention: By utilizing different ADC converter modules built into the central processing unit, the key input analog signal is input to different ADC conversion channels, thereby ensuring the consistency and reliability of the input signal; 3. System Operation Monitoring: This system monitors the operational status of the MCU core modules (ROM, RAM, STACK, ALU, etc.) for anomalies, and includes a watchdog monitoring function. Specific implementation of this invention: 1) Through the built-in self-test and diagnostic registers of the central processing unit and... 4. Related modules monitor internal MCU faults; 2) The watchdog module adopts a timed feeding mechanism; 3) If the watchdog is reset more than a preset specific number of times, the entire system enters a safe sleep mode; 5. Fault Diagnosis and Protection: Fault diagnosis, detection, recovery, abnormal response, and protection mechanisms are implemented for the voltage, system temperature, and drive current feedback of the electronic control system. Specific implementation methods of this invention include: 1) Sampling and diagnosing overvoltage and undervoltage of the power supply voltage of the wiper control system; 2) Diagnosing faults such as short circuit, open circuit, and overload of each input and output module of the wiper control system; 3) Sampling and diagnosing the temperature of the wiper control system (gear end temperature, control board temperature, etc.).

[0022] Level 3: Application Software Functional Safety Layer. This level includes the following functional safety mechanisms: 1. Program flow monitoring: Confirming and verifying the rationality of the wiper motion control logic; Specific implementation of the invention: Monitoring the rationality of the application software module operation through software logic calculation process and variable rationality verification; 2. Limp-off control strategy: Diagnose and verify the communication commands for wiper motion control. In the event of communication abnormalities or circuit breaks, a limp-off redundant wiper control mechanism is triggered and activated. Specific implementation of the invention: 1) When the vehicle's LIN communication is abnormal and the wiper control signal is not received, a low-level signal is output to the wiper control system on the hard wire after the driver activates a specific position of the mechanical switch; 2) When the wiper control system receives the low-level signal from the hard wire, it activates and maintains the normal wiping function of the wipers. 3. Wiper Motion Monitoring: Monitors the position, speed, and acceleration of the wiper motor during its movement, tracking abnormal conditions such as overheating, overload, and stalling; Specific implementation of this invention: 1) Provides overheat protection for the wiper system, including slow temperature rise protection mode and fast temperature rise protection mode; 2) Monitors abnormal scenarios such as dry wiping, heavy load, and stalling by monitoring the wiper control output torque and current; like Figure 3 As shown, during the operation of the electronic wiper control system, the wiper control system is diagnosed and monitored through the collaboration of various levels. When a fault occurs, it can be reported in a timely manner. At the same time, redundant drive circuits are provided to realize system degradation and ensure driving safety.

[0023] The fault analysis and processing steps include:

[0024] (1) Power-on self-test: The system has a built-in self-test mechanism for the power-on startup phase, which includes detection and diagnosis mechanisms for core functional modules such as MCU initialization, clock, watchdog, ROM, and RAM; (2) Continuous periodic fault detection and diagnosis protection mechanism during system operation: The system uses millisecond-level periodic tasks to be executed continuously, covering the operation of all functional safety monitoring modules in level two, as well as No.9 and No.10 in level three mentioned above; (3) Wiper limp control strategy when the whole vehicle interaction fails: adopts an event-triggered response mechanism when the fault occurs, covering No.10 of the above level three.

Claims

1. A wiper control system, characterized in that, include: The signal and sensor input module is connected to the body controller or domain controller for inputting power supply, wiper angle and ambient temperature signals. The MCU processing module has its signal input terminal connected to the signal output terminal of the signal and sensor input module. It is used to parse the control commands of the wiper system, manage the status of the wiper system, perform ADC control, calculate the wiper position, manage the power supply of the wiper control system, control the wiper motion, and perform diagnostic protection and safety monitoring of the wiper control system. A motor pre-drive module, wherein the signal input terminal of the motor pre-drive module is connected to the signal output terminal of the MCU processing module, for use in driving and controlling the wiper movement and providing feedback; The motor power drive module has its signal input terminal connected to the signal output terminal of the motor pre-drive module, and its signal output terminal connected to the wiper motor control for controlling the wiper motor drive and current feedback.

2. The wiper control system according to claim 1, characterized in that, The wiper control system diagnostic protection and safety monitoring of the MCU processing module adopts a layered modular functional safety architecture, which includes a hardware functional safety mechanism layer, a platform software functional safety mechanism layer, and an application software functional safety mechanism layer.

3. A wiper control system according to claim 2, characterized in that, The hardware functional safety mechanism layer includes redundant sensor input circuits, redundant vehicle interaction links, an independent watchdog module, and a fault diagnosis circuit.

4. A wiper control system according to claim 2, characterized in that, The platform software functional safety mechanism layer includes a system power-on self-test mechanism, a redundant ADC conversion verification mechanism, a communication end-to-end protection mechanism, and a driver fault diagnosis and protection mechanism.

5. A wiper control system according to claim 1, characterized in that, The application software functional safety mechanism layer includes a system operation monitoring mechanism, a limp control strategy mechanism, and a wiper movement monitoring mechanism.

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