Rail transit vehicle wiper control circuit

Abstract

The application discloses a rail transit vehicle wiper control circuit, and relates to the technical fields of rail transit and wiper control.The circuit comprises: a power conversion module for receiving direct current power supply and converting the same into multiple power supply voltages; a driving module for converting the direct current power supply into alternating current driving electricity for driving a wiper motor to operate; a position detection module for detecting the position of a wiper execution mechanism and outputting a position feedback signal; a state detection module for detecting the operating state of the wiper motor and / or the driving module and outputting a state feedback signal; an input detection module for detecting a working mode selection signal output by a vehicle control end and outputting a mode input signal; and a control module connected with each module, which determines the current working mode according to the mode input signal, and switches to the corresponding working mode according to the change of the mode input signal during operation, so that the power supply adaptation capability, operating stability, control precision, safety and reliability of the circuit are improved.

Description

Technical Field

[0001] This invention relates to the field of rail transit and windshield wiper control technology, and in particular to a windshield wiper control circuit for rail transit vehicles. Background Technology

[0002] Rail transit vehicles, such as high-speed trains, subways, and intercity trains, are typically equipped with windshield wipers to ensure clear visibility for the driver and improve driving safety. Most existing rail transit vehicles use a 110V DC power supply system, requiring the wiper control circuit to simultaneously accommodate vehicle power supply compatibility, motor drive control, and operational safety protection. However, current wiper control systems still have shortcomings in areas such as power supply compatibility, drive control, mode switching, and safety protection.

[0003] Existing rail transit wiper controllers typically rely on limit switches or simple periodic timing to control the motor's start and stop, lacking refined trajectory planning for the wiper arm's movement. In actual operation, factors such as load variations, wind resistance changes, and mechanical wear can easily cause speed fluctuations and positional deviations in the wiper arm. However, traditional control methods only perform reversing or stopping control near the wiper tip, making it difficult to correct positional errors in real time during operation. This can easily lead to problems such as overshoot, insufficient return, or inaccurate stopping.

[0004] In addition, existing drive protection strategies are usually quite simple, such as directly cutting off the drive output after detecting overcurrent. Although this type of protection can avoid device damage to a certain extent, it may cause the wipers to suddenly stop working under instantaneous load changes or temperature rises, thereby affecting the driver's visibility.

[0005] Therefore, it is necessary to provide a wiper control circuit that can be adapted to the 110V DC power supply system of rail transit vehicles and take into account both drive control and protection control. Summary of the Invention

[0006] The purpose of this invention is to provide a windshield wiper control circuit for rail transit vehicles, so as to at least solve the shortcomings of existing windshield wiper control systems in terms of 110V DC power supply adaptation, drive control and protection control coordination.

[0007] The first aspect of the present invention provides a windshield wiper control circuit for rail transit vehicles, comprising: The power conversion module is used to receive DC power from rail transit vehicles and convert it into multiple power supply voltages; The drive module has its power input terminal connected to the DC power supply, its control input terminal receiving control signals, and its output terminal connected to the wiper motor, and is used to convert the DC power supply into AC drive power to drive the wiper motor. The position detection module is used to detect the position of the wiper actuator and output a position feedback signal; A status detection module is used to detect the operating status of the wiper motor and / or the drive module and output a status feedback signal; The input detection module is used to detect the working mode selection signal output by the vehicle control terminal and output the mode input signal. The control module is connected to the power conversion module, drive module, position detection module, status detection module, and input detection module, respectively. The control module is configured as follows: The current working mode is determined based on the mode input signal, and the system switches to the corresponding working mode during operation based on changes in the mode input signal. A drive control signal is generated based on the position feedback signal and the preset wiping trajectory to control the wiper actuator to reciprocate between a first position and a second position in the wiping area. The drive control signal includes at least an acceleration phase, a constant speed phase, and a deceleration phase. During the uniform speed phase, the duration of the uniform speed phase is adjusted according to the deviation between the actual position represented by the position feedback signal and the position corresponding to the preset brush trajectory, in order to compensate for the brush position error. The system performs protection control based on the status feedback signal, wherein when an abnormality is detected, the drive module is controlled to dredge its output or stop driving output.

[0008] Preferably, the drive module includes an IPM module, which integrates a full-bridge power circuit and a logic drive circuit. The power input terminal of the full-bridge power circuit is connected to the DC power supply of the rail transit vehicle. The logic drive circuit receives the logic control signal output by the control module and drives the full-bridge power circuit to control the power conversion. The IPM module adopts a natural heat dissipation method.

[0009] Preferably, the position detection module includes an angle sensor, which is disposed on the worm shaft or turbine shaft of the windshield wiper and is used to detect the rotation angle of the worm shaft or turbine shaft. The control module is also used to calculate the real-time position, direction of movement and rotation speed of the wiper arm based on the feedback signal output by the angle sensor, and to control the commutation timing and drive parameters of the wiper motor based on the real-time position, direction of movement and rotation speed, so as to realize the wiper arm reciprocating between the first position and the second position and stopping precisely.

[0010] Preferably, the power conversion module includes a first-stage conversion circuit, a second-stage conversion circuit, and a third-stage conversion circuit; the first-stage conversion circuit is a DC-DC converter circuit, used to convert the DC bus voltage of the rail transit vehicle into a first intermediate voltage to power the drive module; the second-stage conversion circuit is a DC-DC converter circuit or an LDO regulator circuit, used to convert the first intermediate voltage into a second intermediate voltage to power the peripheral communication module and interface module; the third-stage conversion circuit is an LDO regulator circuit, used to convert the second intermediate voltage into a logic operating voltage to power the control module.

[0011] Preferably, the input detection module includes an optocoupler isolation circuit. The input terminal of the optocoupler isolation circuit is connected to the gear selection switch on the train control panel, and the output terminal of the optocoupler isolation circuit is connected to the control module. It is used to electrically isolate the initial gear status signal output by the gear selection switch and convert it into a logic control signal adapted to the control module as the mode input signal. The operating modes include at least a first rate mode, a second rate mode, an intermittent mode, an intelligent mode, and a water spray mode.

[0012] Preferably, the control module is configured as follows: Obtain the relative positional relationship between the actual position and the position corresponding to the preset brush trajectory; When it is determined that the actual position is ahead of the position corresponding to the preset brushing trajectory, the duration of the constant speed phase is shortened so as to enter the deceleration phase in advance; When it is determined that the actual position is behind the position corresponding to the preset brush trajectory, the duration of the constant speed phase is extended to delay the entry into the deceleration phase.

[0013] Preferably, the control module is configured as follows: The drive control signal is output by adjusting the duty cycle of the pulse width modulation (PWM) signal; During the acceleration phase, the duty cycle of the PWM signal is controlled to increase from its initial value to the target duty cycle according to a preset slope. During the constant speed phase, the target duty cycle is maintained at a constant output. During the deceleration phase, the duty cycle of the PWM signal is controlled to decrease from the target duty cycle to the initial value according to a preset slope; The target duty cycle and the preset slope are matched with the current working mode.

[0014] Preferably, the status detection module includes a voltage sampling circuit, a current sampling circuit, and a temperature detection circuit; the voltage sampling circuit is used to detect the voltage of the DC power supply, the current sampling circuit is used to detect the phase current and / or bus current of the wiper motor, and the temperature detection circuit is used to detect the temperature of the drive module. The control module is specifically configured to perform the protection control as follows: During the power-on initialization phase, if the DC power supply is determined to be over-voltage or under-voltage based on the detection result of the voltage sampling circuit, the output of the drive module is prohibited. During operation, if an overcurrent is detected based on the current sampling circuit, the drive module is controlled to stop outputting. If the temperature detection circuit determines that an overheating has occurred, the drive module is controlled to derating its output.

[0015] Preferably, the control circuit further includes a rain sensor communication interface connected to the control module; In the intelligent mode, the control module acquires the rainfall level signal through the rainfall sensor communication interface, and dynamically adjusts the target duty cycle corresponding to the drive control signal according to the preset mapping relationship between rainfall level and operating rate; wherein, the higher the rainfall level, the larger the corresponding target duty cycle is adjusted.

[0016] Preferably, the control circuit further includes a cleaning water pump drive circuit connected to the control module; In the water spray mode, the control module is configured as follows: The external cleaning water pump is started by controlling the cleaning water pump drive circuit, and the operating current of the cleaning water pump is detected by the status detection module. Once the operating current of the cleaning water pump is determined to be within the normal range, the control module generates the drive control signal to control the wiper actuator to complete at least one reciprocating wiping action at a preset rate.

[0017] Compared with the prior art, the present invention has the following advantages and positive effects: This invention provides a windshield wiper control circuit for rail transit vehicles. By incorporating a power supply module, control module, drive module, IPM module, position detection module, mode selection module, and protection module, it achieves adaptation to the 110V DC power supply system of rail transit vehicles, stable drive of the wiper motor, precise control of the wiper trajectory and stopping position, and protection control for abnormal operating conditions. By dividing the trajectory into acceleration, constant speed, and deceleration stages, and dynamically adjusting the constant speed time based on the deviation between the actual position and the preset trajectory during the constant speed stage, it effectively prevents overshoot or incomplete stopping under different loads, achieving precise closed-loop control of the wiper position. It ensures visibility while driving and reduces mechanical wear; through multi-dimensional status detection of voltage, current, temperature, etc., it can implement graded protection strategies such as disabling output, stopping output, or derating output when abnormalities occur, to prevent device burnout; it uses an IPM module to realize the conversion of high-voltage DC to AC, and achieves smooth acceleration and deceleration through PWM duty cycle slope control, eliminating the mechanical shock of traditional relay control; since the position detection signal can be fed back to the control module and participate in the motor operation adjustment, and the drive control and protection control work together, it can improve the power supply adaptability, operational stability, control accuracy, safety and reliability of the wiper control circuit. Attached Figure Description

[0018] Figure 1 This is a circuit diagram of the windshield wiper control for a rail transit vehicle in an embodiment of the present invention; Figure 2 This is a basic control timing logic diagram of a single board in an embodiment of the present invention; Figure 3 This is a flowchart illustrating the control processes for high-speed mode, low-speed mode, and intermittent mode in an embodiment of the present invention. Figure 4 This is a flowchart of the water spray mode control in an embodiment of the present invention; Figure 5 This is a flowchart of the intelligent mode control in an embodiment of the present invention; Figure 6 This is a schematic diagram illustrating the correspondence between wiper operating speed and rainfall in intelligent mode in an embodiment of the present invention; Figure 7 This is a schematic diagram of the scraper arm's operating angle in an embodiment of the present invention; Figure 8 This is a schematic diagram of the scraper arm's operating trend in an embodiment of the present invention; Figure 9 This illustrates the correspondence between the scraper arm operation and the angle sensor in this embodiment of the invention. Detailed Implementation

[0019] The following detailed description, in conjunction with the accompanying drawings and specific embodiments, provides a further detailed explanation of the vehicle logo switching device and control method proposed in this invention. The advantages and features of this invention will become clearer from the following description and claims.

[0020] The control circuit in this embodiment is specifically designed for the unique operating scenarios of rail transit vehicles (such as high-speed trains, subways, and intercity trains). This scenario has the following significant characteristics: First, the vehicle's power supply platform is a 110V DC high-voltage system, unlike the 12V / 24V systems of ordinary automobiles, requiring the control circuit to possess high-voltage isolation and high-efficiency power conversion capabilities. Second, the windshield wiper system is installed on the exterior of the vehicle's front, and during operation, it must withstand the enormous wind pressure generated by the train's high-speed movement, and in winter, it also faces significant mechanical resistance from ice and snow, resulting in extremely large load fluctuations. Third, rail transit has extremely high requirements for driving safety; if the wipers fail in rainy or snowy weather, it will directly obstruct the driver's vision, leading to serious safety accidents. Therefore, this scenario not only requires a powerful and stable motor drive, but also precise and controllable wiping position with extremely high fault tolerance and protection capabilities.

[0021] This embodiment provides a windshield wiper control circuit for rail transit vehicles, which is applicable to rail transit vehicles such as high-speed rail, subway, and intercity trains that use DC power supply systems, and is especially suitable for windshield wiper drive and control under 110V DC power supply systems.

[0022] like Figure 1 As shown, the windshield wiper control circuit of the rail transit vehicle in this embodiment takes 110V DC power supply as input and is connected in sequence to the power reverse protection module 1, DC-DC module 2, 5V power supply module 3 and 3.3V power supply module 4 to complete the power supply conversion and distribution of the whole machine.

[0023] The reverse power supply protection module 1 is located at the power input terminal and is constructed using a high-power fast recovery diode. It provides reverse protection for the input DC power supply, preventing damage to downstream components caused by reverse polarity connection. The output terminal of the reverse power supply protection module 1 is connected to the input terminal of the DC-DC converter module 2, which converts 110V DC voltage to 15V. The output terminal of the DC-DC converter module 2 is connected to the 5V power supply module 3, the rain sensor power supply circuit 8, and the IPM module 9. The rain sensor power supply circuit 8 supplies power to an external rain sensor, and the IPM module 9 provides power to the windshield wiper brushless motor. The 5V power supply module 3 converts 15V to 5V to provide operating power to the CAN module 5 and other 5V power supply modules. The 3.3V power supply module 4 converts 5V to 3.3V to provide operating power to modules requiring 3.3V power.

[0024] The CAN module 5 is used for communication when the wiper motors are interconnected; the LIN module 6 is used for communication connection when an external rain sensor is connected, and works with the rain power supply circuit 8 to provide communication support between the rain sensor and the wipers; the optocoupler module 7 is used for rotary switch detection, converting the input high-voltage signal into a low-level logic signal that the MCU can recognize after optocoupler isolation, for the MCU to perform functional judgment; the IPM module 9 integrates a full-bridge power circuit and logic drive circuit, used to convert the 110V DC power supply into the AC drive energy required by the brushless motor; the current sampling circuit... Module 10 is used to collect phase line current and / or bus current, and outputs the differential voltage across the sampling resistor to the MCU for calculation after amplification. The angle sensor 11 is used to detect the worm shaft angle signal and determine the wiper arm position based on the signal, thereby controlling the wiper arm starting position, opening angle and wiping speed. The motor worm angle detection module 12 is used to detect the forward / reverse rotation state of the motor and calculate the motor speed. The temperature sensor 13 is used to detect the worm temperature and PCB temperature respectively. The water pump drive circuit 14 is used to connect an external water pump to realize the cleaning function in the water spray mode.

[0025] Furthermore, the MCU is connected to the optocoupler module 7, the rain power supply circuit 8, the IPM module 9, the current sampling circuit module 10, the angle sensor 11, the motor worm gear angle detection module 12, the temperature sensor 13, and the water pump drive circuit 14, respectively. Specifically, the optocoupler module 7 inputs the rotary switch status signal to the MCU as the basis for mode selection; the angle sensor 11 and the motor worm gear angle detection module 12 feed back the position signal, direction signal, and speed signal to the MCU; the current sampling circuit module 10 and the temperature sensor 13 feed back the operating status signal to the MCU so that the MCU can perform overcurrent, overtemperature, and other protection controls; the rain power supply circuit 8 cooperates with the LIN module 6 to provide power and communication interfaces for the rain sensor; the water pump drive circuit 14 is controlled by the MCU in the spray mode to drive the external water pump.

[0026] The windshield wiper control circuit for rail transit vehicles in this embodiment includes a power conversion module, a drive module, a position detection module, a status detection module, an input detection module, and a control module. The power conversion module receives DC power from the rail transit vehicle and converts it into multiple power supply voltages. The drive module's power input terminal is connected to the DC power supply, its control input terminal receives control signals, and its output terminal is connected to the wiper motor, converting the DC power supply into AC drive power to drive the wiper motor. The position detection module detects the position of the wiper actuator and outputs a position feedback signal. The status detection module detects the operating status of the wiper motor and / or the drive module and outputs a status feedback signal. The input detection module detects the operating mode selection signal output from the vehicle control terminal and outputs a mode input signal. The control module is connected to the power conversion module, drive module, position detection module, status detection module, and input detection module to implement drive control, position control, and protection control under different operating modes of the wipers.

[0027] In this embodiment, the control module can be implemented using an MCU, which is configured to: determine the current working mode based on the mode input signal, and switch to the corresponding working mode during operation according to changes in the mode input signal; generate a drive control signal based on the position feedback signal and the preset wiping trajectory to control the wiper actuator to reciprocate between a first position and a second position in the wiping area, wherein the drive control signal includes at least an acceleration phase, a constant speed phase, and a deceleration phase; in the constant speed phase, adjust the duration of the constant speed phase according to the deviation between the actual position represented by the position feedback signal and the corresponding position of the preset wiping trajectory to compensate for the wiping position error; and perform protection control according to the status feedback signal, wherein when an abnormality is detected, control the drive module to derating output or stop drive output.

[0028] In this embodiment, the power conversion module is located at the power input terminal and is used to perform reverse protection and voltage conversion processing on the DC power input to the rail transit vehicle to prevent damage to downstream devices caused by reverse polarity connection, and to provide the required operating voltage to the control module, drive module and peripheral functional modules.

[0029] Furthermore, the power conversion module includes a first-stage conversion circuit, a second-stage conversion circuit, and a third-stage conversion circuit. The first-stage conversion circuit is a DC-DC converter, used to convert the DC bus voltage of the rail transit vehicle into a first intermediate voltage, such as converting 110V DC voltage into 15V voltage, to power the drive module. The second-stage conversion circuit is a DC-DC converter or an LDO regulator circuit, used to convert the first intermediate voltage into a second intermediate voltage, such as converting 15V voltage into 5V voltage, to power the peripheral communication module and interface module. The third-stage conversion circuit is an LDO regulator circuit, used to convert the second intermediate voltage into a logic operating voltage, such as converting 5V voltage into 3.3V voltage, to power the control module.

[0030] Furthermore, the power conversion module includes a reverse power protection unit, which can be located at the power input terminal. In a preferred embodiment, the reverse power protection unit is constructed using a high-power fast recovery diode to balance reverse protection capability and response speed, preventing damage to downstream devices caused by reverse polarity connection of the rail transit vehicle's power supply.

[0031] In one embodiment, the drive module is used to drive the wiper motor. Specifically, the drive module includes an IPM module, which integrates a full-bridge power circuit and a logic drive circuit. The power input terminal of the full-bridge power circuit is connected to the DC power supply of the rail transit vehicle. The logic drive circuit receives the logic control signal output by the control module and drives the full-bridge power circuit to control the power conversion, thereby converting the 110V DC power supply into the AC drive power required to drive the brushless wiper motor.

[0032] In a preferred embodiment, the IPM module has a withstand voltage of not less than 400V and a withstand current of not less than 20A, and adopts a natural heat dissipation method. The drive signal output by the control module can be a 3.3V logic level or a 5V logic level to drive the internal logic drive circuit of the IPM module to work, thereby realizing the drive mode of controlling high-voltage power output with low-voltage logic.

[0033] In this embodiment, the position detection module is used to acquire the real-time position information of the wiper actuator. The position detection module includes an angle sensor, which is mounted on the worm shaft or turbine shaft of the wiper to detect the rotation angle of the worm shaft or turbine shaft. The control module calculates the real-time position, direction of movement, and rotational speed of the wiper arm based on the feedback signal output by the angle sensor, and controls the commutation timing and drive parameters of the wiper motor based on the real-time position, direction of movement, and rotational speed to achieve reciprocating commutation of the wiper arm between a first position and a second position and precise stopping. In one embodiment, a position detection or encoding detection structure composed of multiple Hall sensors can also be used to collect the rotation direction and rotational speed of the motor spindle, and control the motor's direction and speed in combination with the output encoding sequence; or an angle encoder can be used instead of a Hall encoder to achieve detection and control of the motor's speed and direction. All of the above solutions can be considered as optional implementations of the position detection module of this invention.

[0034] In one embodiment, the status detection module is used to detect the operating status of the wiper motor and / or drive module. Specifically, the status detection module includes a voltage sampling circuit, a current sampling circuit, and a temperature detection circuit; the voltage sampling circuit is used to detect the voltage of the DC power supply, the current sampling circuit is used to detect the phase current and / or bus current of the wiper motor, and the temperature detection circuit is used to detect the temperature of the drive module; the control module is specifically configured to perform the protection control as follows: During the power-on initialization phase, if the voltage sampling circuit determines that the DC power supply is overvoltage or undervoltage, the drive module output is disabled. During the operation phase, if the current sampling circuit determines that an overcurrent has occurred, the drive module output is stopped. If the temperature detection circuit determines that an overtemperature has occurred, the drive module output is derating. In one embodiment, the current sampling circuit can acquire the differential voltage signal corresponding to the phase current or bus current through a sampling resistor, and output it to the control module for processing after amplification. The temperature detection circuit can detect not only the drive module temperature but also the worm gear temperature and PCB temperature as needed.

[0035] In this embodiment, the input detection module is used to detect the operating mode selection signal output by the vehicle control terminal. The input detection module includes an optocoupler isolation circuit. The input terminal of the optocoupler isolation circuit is connected to the gear selection switch on the train control panel, and the output terminal of the optocoupler isolation circuit is connected to the control module. It is used to electrically isolate the initial gear position status signal output by the gear selection switch and convert it into a logic control signal adapted to the control module as the mode input signal. In this embodiment, the operating modes include at least a first speed mode, a second speed mode, an intermittent mode, an intelligent mode, and a water spray mode. The first speed mode and the second speed mode can correspond to high-speed mode and low-speed mode, respectively.

[0036] like Figure 2 As shown, in the basic control timing logic of the single-board system, after the system is powered on, the control module first performs initialization detection. Specifically, the control module first determines whether there is overvoltage or undervoltage in the DC power supply based on the detection results of the voltage sampling circuit. If overvoltage or undervoltage is detected, the drive module output is disabled, and the wipers stop working. If no overvoltage or undervoltage is detected, the control module continues to detect the position status of the rotary switch or gear selector switch and switches to the corresponding function module program. Subsequently, the control module periodically scans the switch status signal output by the input detection module. When a change in the mode input signal is detected, the control module switches to the new operating mode; when the mode input signal remains unchanged, the current operating state is maintained. At the same time, the control module monitors the status feedback signal output by the status detection module in real time. When overcurrent is detected, the control module stops outputting; when overtemperature is detected, the control module derating output or reducing speed; if no abnormality is detected, the current operating state is maintained.

[0037] like Figure 3 As shown, in high-speed mode, low-speed mode, and intermittent mode, the control module generates corresponding drive control signals based on the mode input signals to adjust the motor operating speed. Taking high-speed mode as an example, when the rotary switch is switched to the high-speed mode position, the input detection module detects the high-speed mode signal and outputs it to the control module. The control module adjusts the PWM output parameters accordingly, causing the wipers to enter a high-speed operating state. At this time, the position detection module detects the wiper arm shaft angle, running direction, and rotation speed in real time and feeds them back to the control module. The control module then determines whether the operating state in the current mode is normal. For example, the wiper arm operating speed in high-speed mode can be defined as 45 revolutions per minute, in low-speed mode as 25 revolutions per minute, and in intermittent mode as 10 revolutions per minute. The pause time between adjacent wiping actions can be set to approximately 1 second. Of course, the above values ​​are only examples, and those skilled in the art can adjust them according to actual needs such as vehicle model, wiper mechanism, and window area.

[0038] During operation, the control module continuously monitors the status of the switch signal. When the switch signal remains unchanged, the control module maintains the PWM parameters of the corresponding mode unchanged; when a change in the switch signal is detected, the control module adjusts the output PWM signal parameters, thereby regulating the motor speed and switching to the corresponding operating mode. At the same time, the control module continuously monitors overcurrent and overtemperature conditions; when overcurrent occurs, the wipers stop working, and when overtemperature occurs, the wipers are controlled to reduce speed or operate at reduced capacity.

[0039] like Figure 4 As shown, in water spray mode, when the rotary switch is switched to the water spray mode position, the control module controls the cleaning water pump drive circuit to start the external cleaning water pump, and detects the operating current of the cleaning water pump through the status detection module. Once it is determined that the operating current of the cleaning water pump is within the normal range, the control module generates the drive control signal to control the wiper actuator to complete at least one reciprocating wiping motion at a preset speed. Preferably, in one embodiment, the wiper actuator completes one medium-speed reciprocating wiping motion after water spraying to facilitate window cleaning in conjunction with the cleaning fluid.

[0040] like Figure 5 and Figure 6 As shown, in intelligent mode, the control circuit may further include a rain sensor communication interface connected to the control module. Preferably, the rain sensor communication interface may include a LIN communication interface and a corresponding power supply circuit, used to communicate with and supply power to an external rain sensor. In intelligent mode, the control module acquires the rainfall level signal through the rain sensor communication interface and dynamically adjusts the target duty cycle corresponding to the drive control signal according to a preset mapping relationship between rainfall level and operating speed. For example, rainfall levels can be divided into heavy rain, moderate rain, light rain, drizzle, and no rain, each corresponding to different wiper speed ranges. Heavy rain corresponds to the highest operating state in high-speed mode; heavy rain corresponds to the high-speed operating range; moderate rain corresponds to the medium-speed operating range; light rain corresponds to the low-speed operating range; drizzle corresponds to the intermittent operating range; and no rain corresponds to the stop mode. When the rainfall level increases, the control module correspondingly increases the target duty cycle corresponding to the drive control signal; when the rainfall level decreases, the control module correspondingly decreases the target duty cycle. Preferably, the higher the rainfall level, the larger the corresponding adjusted target duty cycle. When rainfall exceeds the preset heavy rain limit, the wipers can maintain operation at the highest speed mode limit. If the control module detects a communication abnormality with the rain sensor, it can either suspend intelligent wiping or switch to a preset safety mode to improve system reliability.

[0041] In one embodiment, if the control module detects an abnormality in the communication of the rain sensor, such as a LIN communication malfunction, the control module may not perform the intelligent wiping action or switch to a preset safety mode to improve the reliability of system operation.

[0042] like Figures 7 to 9 As shown, this embodiment further explains the commutation control and speed control of the windshield wiper. This embodiment is based on the principle of a brushless motor driving a worm gear, which in turn drives a gear and the wiper arm shaft to rotate. The wiper arm shaft oscillates back and forth between a first position and a second position within the wiping range of the viewing window. For ease of explanation, the wiping range can be defined as 0° to 90°. When the wiper arm moves from 0° to 90°, the motor rotates in the forward direction; when the wiper arm returns from 90° to 0°, the motor rotates in the reverse direction. The timing of the motor commutation is determined by the position signal fed back by the angle sensor. When the wiper arm is detected to have reached the preset endpoint position, the control module controls the drive module to switch the motor direction.

[0043] Furthermore, the control module generates a drive control signal based on the position feedback signal and the preset wiping trajectory to control the wiper actuator to reciprocate between a first position and a second position in the wiping area, wherein the drive control signal includes at least an acceleration phase, a constant speed phase, and a deceleration phase.

[0044] In one embodiment, the control module is configured to: output the drive control signal by adjusting the duty cycle of the pulse width modulation (PWM) signal; during the acceleration phase, control the duty cycle of the PWM signal to increase from an initial value to a target duty cycle according to a preset slope; during the constant speed phase, maintain the target duty cycle at a constant output; during the deceleration phase, control the duty cycle of the PWM signal to decrease from the target duty cycle to the initial value according to a preset slope; wherein the target duty cycle and the preset slope are matched with the current operating mode. For example, in high-speed mode, the brush rotation speed can be 45 revolutions per minute, and the time for the scraper arm to move from 0° to 90° is approximately 0.67 seconds. During this process, the scraper arm first experiences an acceleration phase of approximately 150 ms, then a constant speed phase of approximately 370 ms, and finally a deceleration phase of approximately 150 ms, thereby reducing the rotation speed to near zero at the endpoint. Correspondingly, the control module can control the PWM duty cycle to gradually increase from 0 to the target duty cycle, for example, about 60%, during the acceleration phase; maintain the target duty cycle during the constant speed phase; and reduce the duty cycle to 0 during the deceleration phase. The control logic for the scraper arm to return from 90° to 0° is the same as the above process.

[0045] To improve the accuracy of brush position control and prevent overshoot or undershoot under different loads and operating conditions, the control module adjusts the duration of the constant speed phase based on the deviation between the actual position represented by the position feedback signal and the corresponding position of the preset brush trajectory during the constant speed phase, thereby compensating for brush position errors. Specifically, the control module acquires the relative positional relationship between the actual position and the corresponding position of the preset brush trajectory; when it is determined that the actual position is ahead of the corresponding position of the preset brush trajectory, the duration of the constant speed phase is shortened to advance the deceleration phase; when it is determined that the actual position is behind the corresponding position of the preset brush trajectory, the duration of the constant speed phase is extended to delay the deceleration phase. Through this method, precise control of the brush arm end position and the brush trajectory can be achieved.

[0046] In this embodiment, the status detection module is also used to implement protection control for abnormal system operating conditions. Specifically, during the power-on initialization phase, if the DC power supply is determined to be overvoltage or undervoltage based on the detection result of the voltage sampling circuit, the control module disables the output of the drive module; during the operation phase, if the drive module is determined to be overcurrent based on the detection result of the current sampling circuit, the drive module is controlled to stop output; if the drive module is determined to be overtemperature based on the detection result of the temperature detection circuit, the drive module is controlled to derating its output. Through overvoltage, undervoltage, overcurrent, and overtemperature protection, the safety and operational reliability of the wiper control circuit can be effectively improved.

[0047] In an optional embodiment, the control circuit further includes a CAN module connected to the control module, used to provide communication support in wiper motor interconnection scenarios. The CAN module can be supplied with operating voltage by the power conversion module and interacts with the control module to meet the system's expanded communication needs.

[0048] In another optional embodiment, the control circuit further includes a washer pump drive circuit connected to the control module for connecting an external water pump; it may also include a rain sensor power supply circuit and a communication interface for expanding the rain sensor's functionality. The above functional modules can be selected as backup expansion functions based on the actual vehicle configuration requirements. In spray mode, the control module is configured to: control the washer pump drive circuit to start the external washer pump, and detect the operating current of the washer pump through the status detection module; when it is determined that the operating current of the washer pump is within the normal range, the control module generates the drive control signal to control the wiper actuator to complete at least one reciprocating wiping action at a preset rate.

[0049] The present invention also provides a method for controlling windshield wipers in rail transit vehicles, comprising the following steps: Step 1: Power-on initialization. The DC power supply voltage of the rail transit vehicle is detected by the voltage sampling circuit. If it is determined that the DC power supply is over-voltage or under-voltage, the drive module output is prohibited. Step 2: Detect the working mode selection signal output by the vehicle control terminal through the input detection module to determine the current working mode. The working modes include high-speed mode (wiper arm speed ≥ 45 rpm), low-speed mode (wiper arm speed 25 rpm), intermittent mode (wiper arm speed 10 rpm), intelligent mode, and water spray mode. Step 3: Perform corresponding control according to the current working mode: (1) When the current working mode is high speed mode, low speed mode or intermittent mode, the control module adjusts the duty cycle parameter of the pulse width modulation (PWM) signal to the corresponding mode state, and detects the rotation speed of the wiper arm through the position detection module to determine whether the working mode selection signal has changed. If it has changed, the PWM signal parameter is adjusted. If it has not changed, the current of the wiper motor and the temperature of the drive module are detected through the status detection module. (2) When the current working mode is intelligent mode, the control module turns on the power supply of the rain sensor, detects whether the communication of the rain sensor is normal through the rain sensor communication interface. If it is normal, the rain level signal is received, and the target duty cycle of the PWM signal is dynamically adjusted according to the preset mapping relationship between the rain level and the running speed. (3) When the current working mode is water spray mode, the control module starts the cleaning water pump drive circuit, detects the working current of the cleaning water pump through the status detection module. If the working current is in the normal range, a drive control signal is generated to control the wiper actuator to complete at least one reciprocating wiping action at a preset speed. Step 4: Based on the position feedback signal output by the position detection module, obtain the relative positional relationship between the actual position of the scraper arm and the position corresponding to the preset scraping trajectory. During the uniform speed phase of the scraping motion, when it is determined that the actual position is in front of the position corresponding to the preset scraping trajectory, shorten the duration of the uniform speed phase to enter the deceleration phase in advance. When it is determined that the actual position is behind the position, extend the duration of the uniform speed phase to delay entering the deceleration phase, so as to compensate for the scraping position error. Step 5: Execute protection control based on the status feedback signal output by the status detection module: If overcurrent is detected by the current sampling circuit, control the drive module to stop outputting; if overtemperature is detected by the temperature detection circuit, control the drive module to derating output.

[0050] The voltage level, rotation speed, time parameters, duty cycle, rainfall level classification, sensor type and communication method in the above embodiments can be adjusted according to the specific application scenario, and do not constitute a limitation on the scope of protection of the present invention.

[0051] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to the above embodiments. Even if various changes are made to the present invention, if these changes fall within the scope of the claims of the present invention and their equivalents, they shall still fall within the protection scope of the present invention.

Claims

1. A windshield wiper control circuit for rail transit vehicles, characterized in that, include: The power conversion module is used to receive DC power from rail transit vehicles and convert it into multiple power supply voltages; The drive module has its power input terminal connected to the DC power supply, its control input terminal receiving control signals, and its output terminal connected to the wiper motor, and is used to convert the DC power supply into AC drive power to drive the wiper motor. The position detection module is used to detect the position of the wiper actuator and output a position feedback signal; A status detection module is used to detect the operating status of the wiper motor and / or the drive module and output a status feedback signal; The input detection module is used to detect the working mode selection signal output by the vehicle control terminal and output the mode input signal. The control module is connected to the power conversion module, drive module, position detection module, status detection module, and input detection module, respectively. The control module is configured as follows: The current working mode is determined based on the mode input signal, and the system switches to the corresponding working mode during operation based on changes in the mode input signal. A drive control signal is generated based on the position feedback signal and the preset wiping trajectory to control the wiper actuator to reciprocate between a first position and a second position in the wiping area. The drive control signal includes at least an acceleration phase, a constant speed phase, and a deceleration phase. During the uniform speed phase, the duration of the uniform speed phase is adjusted according to the deviation between the actual position represented by the position feedback signal and the position corresponding to the preset brush trajectory, in order to compensate for the brush position error. The system performs protection control based on the status feedback signal, wherein when an abnormality is detected, the drive module is controlled to dredge its output or stop driving output.

2. The windshield wiper control circuit for rail transit vehicles according to claim 1, characterized in that, The drive module includes an IPM module, which integrates a full-bridge power circuit and a logic drive circuit. The power input terminal of the full-bridge power circuit is connected to the DC power supply of the rail transit vehicle. The logic drive circuit receives the logic control signal output by the control module and drives the full-bridge power circuit to control the power conversion. The IPM module adopts a natural heat dissipation method.

3. The windshield wiper control circuit for rail transit vehicles according to claim 1, characterized in that, The position detection module includes an angle sensor, which is mounted on the worm shaft or turbine shaft of the windshield wiper and is used to detect the rotation angle of the worm shaft or turbine shaft. The control module is also used to calculate the real-time position, direction of movement and rotation speed of the wiper arm based on the feedback signal output by the angle sensor, and to control the commutation timing and drive parameters of the wiper motor based on the real-time position, direction of movement and rotation speed, so as to realize the wiper arm reciprocating between the first position and the second position and stopping precisely.

4. The windshield wiper control circuit for rail transit vehicles according to claim 1, characterized in that, The power conversion module includes a first-stage conversion circuit, a second-stage conversion circuit, and a third-stage conversion circuit. The first-stage conversion circuit is a DC-DC converter circuit, used to convert the DC bus voltage of the rail transit vehicle into a first intermediate voltage to power the drive module. The second-stage conversion circuit is a DC-DC converter circuit or an LDO regulator circuit, used to convert the first intermediate voltage into a second intermediate voltage to power the peripheral communication module and interface module. The third-stage conversion circuit is an LDO regulator circuit, used to convert the second intermediate voltage into a logic operating voltage to power the control module.

5. The windshield wiper control circuit for rail transit vehicles according to claim 1, characterized in that, The input detection module includes an optocoupler isolation circuit. The input terminal of the optocoupler isolation circuit is connected to the gear selection switch on the train control panel, and the output terminal of the optocoupler isolation circuit is connected to the control module. It is used to electrically isolate the initial gear status signal output by the gear selection switch and convert it into a logic control signal adapted to the control module as the mode input signal. The working modes include at least a first rate mode, a second rate mode, an intermittent mode, an intelligent mode, and a water spray mode.

6. The windshield wiper control circuit for rail transit vehicles according to claim 1, characterized in that, The control module is configured as follows: Obtain the relative positional relationship between the actual position and the position corresponding to the preset brush trajectory; When it is determined that the actual position is ahead of the position corresponding to the preset brushing trajectory, the duration of the constant speed phase is shortened so as to enter the deceleration phase in advance; When it is determined that the actual position is behind the position corresponding to the preset brush trajectory, the duration of the constant speed phase is extended to delay the entry into the deceleration phase.

7. The windshield wiper control circuit for rail transit vehicles according to claim 1, characterized in that, The control module is configured as follows: The drive control signal is output by adjusting the duty cycle of the pulse width modulation (PWM) signal; During the acceleration phase, the duty cycle of the PWM signal is controlled to increase from its initial value to the target duty cycle according to a preset slope. During the constant speed phase, the target duty cycle is maintained at a constant output. During the deceleration phase, the duty cycle of the PWM signal is controlled to decrease from the target duty cycle to the initial value according to a preset slope; The target duty cycle and the preset slope are matched with the current working mode.

8. The windshield wiper control circuit for rail transit vehicles according to claim 1, characterized in that, The status detection module includes a voltage sampling circuit, a current sampling circuit, and a temperature detection circuit; the voltage sampling circuit is used to detect the voltage of the DC power supply, the current sampling circuit is used to detect the phase current and / or bus current of the wiper motor, and the temperature detection circuit is used to detect the temperature of the drive module. When the control module executes the protection control, it is specifically configured as follows: During the power-on initialization phase, if the DC power supply is determined to be over-voltage or under-voltage based on the detection result of the voltage sampling circuit, the output of the drive module is prohibited. During operation, if an overcurrent is detected based on the current sampling circuit, the drive module is controlled to stop outputting. If the temperature detection circuit determines that an overheating has occurred, the drive module is controlled to derating its output.

9. The windshield wiper control circuit for rail transit vehicles according to claim 5, characterized in that, The control circuit also includes a rain sensor communication interface connected to the control module; In the intelligent mode, the control module acquires the rainfall level signal through the rainfall sensor communication interface, and dynamically adjusts the target duty cycle corresponding to the drive control signal according to the preset mapping relationship between rainfall level and operating rate; wherein, the higher the rainfall level, the larger the corresponding target duty cycle is adjusted.

10. The windshield wiper control circuit for rail transit vehicles according to claim 5, characterized in that, The control circuit also includes a cleaning water pump drive circuit connected to the control module. In the water spray mode, the control module is configured as follows: The external cleaning water pump is started by controlling the cleaning water pump drive circuit, and the operating current of the cleaning water pump is detected by the status detection module. Once the operating current of the cleaning water pump is determined to be within the normal range, the control module generates the drive control signal to control the wiper actuator to complete at least one reciprocating wiping action at a preset rate.

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