Automobile air conditioner air door control system

Abstract

The utility model discloses an air door control system of an automobile air conditioner, which is characterized in that a main node is arranged on a CAN (Controller Area Network) bus; the LIN bus is provided with a plurality of air conditioner air door actuators serving as slave nodes; the slave nodes are in communication connection with the master node through an LIN bus; the master node is used for distributing communication addresses to the slave nodes, so that the problem that in the prior art, manual setting of the communication addresses is high in cost and prone to errors is solved, meanwhile, the current induction amplification unit is adopted, and when the motor is locked, current changes in a motor loop are detected in real time; and then a user is informed that the actuator breaks down on an interactive interface of the intelligent automobile in a form of exclamation marks, so that motor stalling detection and early warning are realized.

Description

Technical Field

[0001] The utility model relates to the field of air conditioner damper control, in particular to an automobile air conditioner damper control system. Background Art

[0002] As one of the key components in the air conditioning control system of intelligent vehicles, the damper actuator can control the air outlet angle and air volume of the air conditioner. Its performance greatly affects the comfort of passengers in the car. Traditional damper actuators require manual setting of communication addresses, which is costly and error-prone in a large number of intelligent vehicles with complex layouts. In addition, traditional damper actuators lack the ability to automatically detect stalls, and car owners or maintenance personnel must rely on manual inspection to confirm the problem, which is not only inefficient, but also prone to more serious problems due to negligence or delay, such as motor overheating and damage, and may even affect the normal operation of the entire air conditioning system. Utility Model Content

[0003] In order to realize the automatic addressing function of the damper actuator, avoid the high cost and error-prone problem of manually setting the communication address of the traditional damper actuator, and realize the real-time monitoring of the motor current of each damper actuator to avoid the problem of motor overheating or damage, the utility model proposes an automobile air conditioning damper control system, including:

[0004] MCU module;

[0005] A CAN-LIN network module includes a CAN bus and a LIN bus; a master node is provided on the CAN bus; a plurality of air conditioner damper actuators as slave nodes are provided on the LIN bus; the slave nodes are connected to the master node through LIN bus communication;

[0006] The master node is used to allocate communication addresses to the slave nodes;

[0007] The MCU module is used to receive the air conditioner damper control command, and encode the air conditioner damper control command into a CAN message and send it to each node via the CAN bus;

[0008] The slave node is used to monitor the CAN messages sent by the MCU module, decode the CAN messages related to it, generate corresponding motor control instructions, and control the running speed and direction of the motor based on the motor control instructions, thereby realizing precise positioning control of the air conditioner damper.

[0009] Furthermore, the air conditioner damper actuator comprises: a micro control unit, a CAN communication unit, a motor drive unit and a motor;

[0010] The CAN communication unit is used to monitor the CAN messages sent by the MCU module and transmit the CAN messages related to it to the corresponding micro control unit;

[0011] The microcontroller unit is also used to decode the CAN message, generate corresponding motor control instructions, and send them to the corresponding motor drive unit;

[0012] The motor drive unit controls the running speed and direction of the motor based on the motor control instruction, thereby realizing precise positioning control of the air conditioner damper.

[0013] Furthermore, the air conditioning damper actuator also includes:

[0014] The current sensing amplifier unit is used to detect and amplify the current signal of the motor circuit in the corresponding motor, and convert it into a voltage signal, generate a warning signal according to the size of the voltage signal and send it to the corresponding micro control unit.

[0015] Furthermore, the air conditioner damper actuator also includes: a power conversion module, which is used to convert the power supply voltage of the car battery into the working voltage required by the motor drive unit and the current sensing amplifier unit, and output it to the motor drive unit and the current sensing amplifier unit.

[0016] Furthermore, the current sensing amplification unit includes:

[0017] A current sensing amplifier, a first resistor R1, a second resistor R2, a third resistor R3, a first capacitor C1, a first power source VS and a second power source VCC; the current sensing amplifier includes an amplifier U1 and a comparator U2; wherein:

[0018] The first power supply VS is simultaneously connected to one end of the first capacitor C1 and one end of the second resistor R2; the first power supply VS is also connected to the power supply pin vs of the current sensing amplifier and is grounded through the ground pin GND of the current sensing amplifier; the first pin IN- of the amplifier U1 is connected to one end of the first resistor R1 and is connected to the motor current signal, the second pin IN+ is connected to the other end of the first resistor R1 and is connected to the second power supply VCC, the third pin is connected to a stable voltage source providing a first reference voltage threshold, and the fourth pin is connected to the ADC module in the corresponding micro control unit and is connected to the first pin of the comparator U2; the warning voltage threshold pin ALERT of the comparator U2 is connected to the other end of the second resistor R2 and then connected to the first input port GPIO1 in the corresponding micro control unit; the over-limit alarm voltage threshold pin LIMIT1 of the comparator U2 is connected to one end of the third resistor R3; the latch voltage pin LATCH of the comparator U2 is connected to the second input port GPIO2 in the corresponding micro control unit; the other end of the third resistor R3 is grounded; the other end of the first capacitor C1 is grounded.

[0019] Furthermore, the microcontroller unit is also used to send an addressing request signal to each node of the CAN-LIN network module; the CAN communication unit is also used to monitor the addressing request signals issued by other slave nodes; the microcontroller unit is also used to respond to the addressing request signals issued by other slave nodes based on the allocation status of its own communication address; the master node is specifically used to allocate a communication address to the slave node that sends the addressing request signal and responds.

[0020] Furthermore, each of the slave nodes is assigned a corresponding node ID; the CAN communication unit is specifically used to monitor the CAN messages sent by the MCU module, and at the same time identify the CAN messages with matching IDs through the corresponding node ID and the message ID in the CAN message, and transmit the CAN message to the corresponding micro control unit.

[0021] Compared with the prior art, the present invention has at least the following beneficial effects:

[0022] (1) In the present invention, a master node is provided on the CAN bus; a plurality of air conditioner damper actuators as slave nodes are provided on the LIN bus; the slave nodes are connected to the master node through the LIN bus communication; the master node is used to assign communication addresses to the slave nodes; the MCU module is used to receive air conditioner damper control instructions, and at the same time encode the air conditioner damper control instructions into CAN messages and send them to each node through the CAN bus; the slave node is used to monitor the CAN messages sent by the MCU module, decode the CAN messages related to it, generate corresponding motor control instructions, and control the running speed and direction of the motor based on the motor control instructions, so as to realize precise positioning control of the air conditioner damper; that is, in the present invention, when a new air conditioner damper actuator is added to the CAN-LIN network module, the master node assigns a communication address to the slave node, thereby solving the problem of high cost and easy error in manually setting the communication address in the prior art;

[0023] (2) In the present invention, the current sensing amplifier unit is used to detect and amplify the current signal of the motor circuit in the corresponding motor, and convert it into a voltage signal. According to the size of the voltage signal, a warning signal is generated and sent to the corresponding micro control unit, which solves the problem that the traditional damper actuator lacks the ability to automatically detect the stall. The owner or maintenance personnel must rely on manual detection to confirm the problem, resulting in low efficiency and the problem that the motor is easily damaged due to negligence or delay;

[0024] (3) In the present invention, when the input voltage signal exceeds the first reference voltage threshold, the output state of the fourth pin of the amplifier U1 is changed, and the microcontroller unit converts the output signal of the fourth pin of the amplifier U1 into a digital signal through the ADC module, and determines the stall state of the corresponding motor through the digital signal; at the same time, when the input voltage value is greater than the second reference voltage threshold, the warning voltage threshold pin ALERT is pulled low to generate a warning signal, and the warning signal is input into the corresponding microcontroller unit, thereby realizing real-time early warning of motor monitoring. That is, the present invention realizes real-time monitoring and real-time early warning of motor stall, thereby improving the safety of motor use. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a structural diagram of a car air conditioning damper control system;

[0026] Figure 2 This is the structure diagram of the air conditioner damper actuator;

[0027] Figure 3 This is the CAN-LIN bus communication structure diagram;

[0028] Figure 4 is the circuit diagram of the current sensing amplifier unit;

[0029] Figure 5 The present invention is a flow chart of a method for controlling an automobile air-conditioning damper. DETAILED DESCRIPTION

[0030] The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solution of the present invention, but the present invention is not limited to these embodiments.

[0031] In order to realize the automatic addressing function of the damper actuator, avoid the high cost and error-prone problem of manually setting the communication address of the traditional damper actuator, and realize the real-time monitoring of the motor current of each damper actuator to avoid the problem of motor overheating or damage, such as Figure 1 As shown, the utility model proposes an automobile air conditioner damper control system, comprising:

[0032] MCU module;

[0033] CAN-LIN network module, such as Figure 3 As shown ( Figure 3 The embodiment of the CAN-LIN bus communication structure of the CAN-LIN network module includes a CAN bus and a LIN bus; a master node is provided on the CAN bus; a plurality of air conditioner damper actuators as slave nodes are provided on the LIN bus; the slave nodes are connected to the master node in communication; the slave nodes are each assigned a corresponding node ID;

[0034] The MCU module is used to receive the air conditioner damper control command, and encode the air conditioner damper control command into a CAN message and send it to each node via the CAN bus;

[0035] It should be noted that the air conditioning damper control command is the command input by the driver through the control panel or the air outlet angle adjustment command issued by the automatic air conditioning system. The air conditioning damper control command includes the target position and movement speed of the damper.

[0036] like Figure 2 As shown, any of the air conditioner damper actuators comprises: a micro control unit, a CAN communication unit, a motor drive unit and a motor; the micro control unit is communicatively connected with the CAN communication unit;

[0037] The micro control unit is used to send an addressing request signal to each node of the CAN-LIN network module through the CAN communication unit;

[0038] The CAN communication unit is used to monitor addressing request signals sent by other slave nodes;

[0039] The micro control unit is also used to respond to addressing request signals sent by other slave nodes based on the allocation status of its own communication address;

[0040] The master node is used to allocate communication addresses to slave nodes that send addressing request signals and respond;

[0041] In this embodiment, when the air conditioning damper actuator is replaced or upgraded, the new air conditioning damper actuator will automatically obtain the communication address and integrate into the CAN-LIN network by sending an addressing request signal, without the need for manual reconfiguration, thereby improving the stability and reliability of the entire automobile air conditioning damper control system.

[0042] The CAN communication unit is also used to monitor the CAN messages (i.e., messages on the CAN bus) sent by the MCU module, and identify the CAN messages with matching IDs through the corresponding node IDs and the message IDs in the CAN messages, and transmit the CAN messages to the corresponding micro control unit;

[0043] It should be explained that although message identification is achieved through the identifier (message ID) of the CAN message, the importance of the pre-assigned communication address for the air conditioner damper actuator to identify related CAN messages lies in that it establishes a matching rule. In actual applications, although the message ID of the CAN message is not direct address information, the system design will associate a specific message ID with the communication address of the damper actuator, so that the air conditioner damper actuator can know which message IDs are related to itself.

[0044] On the CAN bus, although the message does not have a direct address field, the identifier (message ID) of each CAN message plays an indirect addressing role. As a node on the CAN bus, the damper actuator is assigned a node ID that corresponds to the message ID of the CAN message, which means that the damper actuator will determine whether the message is sent to itself based on the message ID, and thus decide whether to process the instructions in the message.

[0045] The microcontroller unit is also used to decode the CAN message, generate the corresponding motor control instruction (i.e., PWM signal), and send it to the corresponding motor drive unit;

[0046] The motor drive unit controls the running speed and direction of the motor based on the motor control instruction, thereby realizing precise positioning control of the air conditioner damper.

[0047] Specifically, during the operation of the air conditioner damper actuator, the microcontroller unit first configures its internal PWM signal generator, including setting the frequency, duty cycle and other parameters of the PWM signal. The PWM signal generated by the microcontroller unit is connected to the motor drive module through the pin interface, and the motor drive unit is responsible for converting the PWM signal into a voltage signal suitable for driving the motor.

[0048] The microcontroller unit controls the average voltage output from the motor drive unit to the motor by changing the duty cycle of the PWM signal.

[0049] The air conditioning damper actuator also includes:

[0050] The current sensing amplifier unit is used to detect and amplify the current signal of the motor circuit in the corresponding motor, and convert it into a voltage signal, generate a warning signal according to the size of the voltage signal and send it to the corresponding micro control unit.

[0051] In this embodiment, when the motor is running, its current passes through the sensing element and generates a corresponding magnetic field. The change in the magnetic field will cause the electromotive force to change. Considering that the amplitude of the electromotive force change is not large, the electromotive force change value (i.e., the motor current signal) is transmitted to the current sensing amplification unit to amplify the amplitude of the electromotive force change to accurately reflect the operating status of the motor.

[0052] like Figure 4 As shown, the current sensing amplification unit includes:

[0053] A current sensing amplifier, a first resistor R1, a second resistor R2, a third resistor R3, a first capacitor C1, a first power source VS and a second power source VCC; the current sensing amplifier includes an amplifier U1 and a comparator U2; wherein:

[0054] The first power supply VS (2.7-5.5V) is connected to one end of the first capacitor C1 and one end of the second resistor R2 at the same time; the first power supply VS is also connected to the power supply pin vs of the current sensing amplifier and is grounded through the ground pin GND of the current sensing amplifier; the first pin IN- of the amplifier U1 is connected to one end of the first resistor R1 and is connected to the motor current signal, the second pin IN+ is connected to the other end of the first resistor R1 and is connected to the second power supply VCC (0-36V), the third pin is connected to the stable voltage source Reference Voltage that provides a first reference voltage threshold, the fourth pin is connected to the ADC module in the corresponding micro control unit and is connected to the first pin of the comparator U2; the warning voltage threshold pin ALERT of the comparator U2 is connected to the other end of the second resistor R2 and then connected to the first input port GPIO1 in the corresponding micro control unit; the over-limit alarm voltage threshold pin LIMIT1 of the comparator U2 is connected to one end of the third resistor R3; the latch voltage pin LATCH of the comparator U2 is connected to the second input port GPIO2 in the corresponding micro control unit; the other end of the third resistor R3 is grounded; the other end of the first capacitor C1 is grounded.

[0055] When the motor is stalled, its loop current will change significantly: when the motor is working normally, the current will remain in a stable range, but when the motor is stalled, the current will rise rapidly and exceed the threshold value during normal operation. Based on this, this embodiment uses a current sensing amplifier unit to detect the dynamic changes of the current in the motor loop with high precision. Once the current sensing amplifier unit detects this abnormal current change, it will immediately trigger the alarm mechanism built into the microcontroller unit, and then notify the user of the failure of the air conditioner damper actuator in the form of an exclamation mark on the human-computer interaction interface of the smart car, thereby realizing the detection and early warning of motor stall.

[0056] The air conditioner damper actuator also includes: a power conversion module, which is used to convert the power supply voltage of the car battery into the working voltage required by the motor drive unit and the current sensing amplifier unit, and output it to the motor drive unit and the current sensing amplifier unit.

[0057] In the utility model, a master node is arranged on the CAN bus; a plurality of air-conditioning damper actuators as slave nodes are arranged on the LIN bus; the slave nodes are communicatively connected with the master node; the CAN communication unit is used to monitor addressing request signals issued by other slave nodes; the micro-control unit is used to respond to addressing request signals issued by other slave nodes based on the allocation status of its own communication address; the master node is used to allocate communication addresses to slave nodes that send addressing request signals and respond; the CAN communication unit is also used to monitor CAN messages issued by the MCU module, and transmit CAN messages related thereto to the corresponding micro-control unit; the motor drive unit controls the running speed and direction of the motor through motor control instructions generated by the micro-control unit based on the CAN messages, that is, in the utility model, when a new air-conditioning damper actuator is added to the CAN-LIN network module, address allocation will be requested through an addressing request signal, thereby solving the problem of high cost and easy error in manually setting the communication address in the prior art.

[0058] like Figure 5 As shown, the application principle of the automobile air conditioning damper control system in this embodiment is as follows:

[0059] The addressing request signal sent by other slave nodes is monitored through the CAN communication unit; the addressing request signal includes a node ID used to reflect the priority, and the smaller the node ID, the higher the priority;

[0060] It should be noted that when a new air conditioner damper actuator node is added to the CAN-LIN network, it will send an addressing request signal containing its priority information to inform other nodes and request the allocation of a communication address.

[0061] The microcontroller unit responds to the addressing request signal sent by other slave nodes based on the allocation status of its own communication address; nodes with higher priority will respond faster; specifically:

[0062] When the CAN communication unit monitors the addressing request signal sent by other slave nodes, the micro control unit determines whether the corresponding air-conditioning damper actuator has been assigned an address. If so, it ignores the addressing request signal; if not, it responds to the addressing request signal and sends a response request signal to the master node through the CAN communication unit; the response request signal includes a node ID used to reflect the priority.

[0063] The master node allocates communication addresses to slave nodes that send addressing request signals and respond; specifically: the master node monitors all response request signals, and according to the priority of all response request signals and the node ID in the current addressing request signal, uses the available address list to allocate communication addresses to the slave nodes corresponding to each request signal.

[0064] It should be noted that if a conflict occurs during the response process (for example, two or more nodes try to send a response request signal at the same time), the node will detect the conflict and take appropriate measures, including resending the response request signal, or sending the response request signal again after a random delay, or waiting for further instructions from the master node. If an error or failure occurs during the automatic addressing process (for example, a node has not successfully assigned a communication address or responded for a long time), the master node can monitor the entire addressing process and take corrective measures or notify the system administrator if necessary. Once the node obtains the communication address, it will send a confirmation signal to the master node. After that, the node can use its new address to communicate in the LIN network.

[0065] The CAN message sent by the MCU module is monitored in real time through the CAN communication unit, and the CAN message with the matching ID is identified through the node ID corresponding to the CAN communication unit and the message ID in the CAN message, and the CAN message is transmitted to the corresponding micro control unit;

[0066] The CAN message transmitted by the CAN communication unit is decoded by the microcontroller unit, a motor control instruction corresponding to the CAN message is generated, and the motor control instruction is sent to the corresponding motor drive unit;

[0067] The motor drive unit uses the motor control instructions to control the running speed and direction of the corresponding motor, thereby achieving precise positioning control of the air conditioning damper.

[0068] At the same time, the current signal of the motor circuit in the corresponding motor is detected in real time through the current sensing amplifier unit, and converted into a voltage signal. A warning signal is generated according to the size of the voltage signal and sent to the corresponding micro control unit.

[0069] The current sensing amplifier unit detects the current signal of the motor circuit in the corresponding motor in real time and converts it into a voltage signal, generates a warning signal according to the size of the voltage signal and sends it to the corresponding micro control unit, specifically including:

[0070] Convert the current signal in the motor circuit into a voltage signal and input it into amplifier U1;

[0071] The amplifier U1 compares the first reference voltage threshold inside it with the input voltage signal. When the input voltage signal exceeds the first reference voltage threshold, the output state of the fourth pin of the amplifier U1 is changed. The microcontroller unit converts the output signal of the fourth pin of the amplifier U1 into a digital signal through the ADC module, and determines the stall state of the corresponding motor through the digital signal.

[0072] In the utility model, the current sensing amplifier unit does not need any peripheral components when connected to the micro control unit, and only needs to be connected to the control circuit of the air conditioner damper actuator.

[0073] The second reference voltage threshold provided by the over-limit alarm voltage threshold pin LIMIT1 is compared with the voltage value input to the fourth pin of the amplifier U1 by the comparator U2. When the input voltage value is greater than the second reference voltage threshold, the warning voltage threshold pin ALERT is pulled low to generate a warning signal, which is then input into the corresponding micro control unit.

[0074] In the utility model, when the input voltage signal exceeds the first reference voltage threshold, the output state of the fourth pin of the amplifier U1 is changed, and the microcontroller unit converts the output signal of the fourth pin of the amplifier U1 into a digital signal through the ADC module, and determines the stall state of the corresponding motor through the digital signal; at the same time, when the input voltage value is greater than the second reference voltage threshold, the warning voltage threshold pin ALERT is pulled low to generate a warning signal, and inputs the corresponding microcontroller unit, thereby realizing real-time early warning of motor monitoring, that is, the present invention realizes real-time monitoring and real-time early warning of motor stall, and improves the safety of motor use.

[0075] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back...) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0076] In addition, in the present invention, the descriptions of "first", "second", "one", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0077] In the present invention, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0078] In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that ordinary technicians in the field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

Claims

1. An automobile air-conditioning damper control system, characterized in that: include: MCU module; A CAN-LIN network module includes a CAN bus and a LIN bus; a master node is provided on the CAN bus; a plurality of air conditioner damper actuators as slave nodes are provided on the LIN bus; the slave nodes are connected to the master node through LIN bus communication; The master node is used to allocate communication addresses to the slave nodes; The MCU module is used to receive the air conditioner damper control command, and encode the air conditioner damper control command into a CAN message and send it to each node via the CAN bus; The slave node is used to monitor the CAN messages sent by the MCU module, decode the CAN messages related to it, generate corresponding motor control instructions, and control the running speed and direction of the motor based on the motor control instructions, thereby realizing precise positioning control of the air conditioner damper.

2. The automotive air conditioner damper control system according to claim 1, characterized in that: The air conditioner damper actuator comprises: a micro control unit, a CAN communication unit, a motor drive unit and a motor; The CAN communication unit is used to monitor the CAN messages sent by the MCU module and transmit the CAN messages related to it to the corresponding micro control unit; The microcontroller unit is also used to decode the CAN message, generate corresponding motor control instructions, and send them to the corresponding motor drive unit; The motor drive unit controls the running speed and direction of the motor based on the motor control instruction, thereby realizing precise positioning control of the air conditioner damper.

3. The automobile air conditioner damper control system according to claim 2, characterized in that: The air conditioning damper actuator also includes: The current sensing amplifier unit is used to detect and amplify the current signal of the motor circuit in the corresponding motor, and convert it into a voltage signal, generate a warning signal according to the size of the voltage signal and send it to the corresponding micro control unit.

4. The automotive air conditioner damper control system according to claim 3, characterized in that: The air conditioner damper actuator also includes: a power conversion module, which is used to convert the power supply voltage of the car battery into the working voltage required by the motor drive unit and the current sensing amplifier unit, and output it to the motor drive unit and the current sensing amplifier unit.

5. The automobile air conditioner damper control system according to claim 4, characterized in that: The current sensing amplification unit comprises: A current sensing amplifier, a first resistor R1, a second resistor R2, a third resistor R3, a first capacitor C1, a first power source VS and a second power source VCC; the current sensing amplifier includes an amplifier U1 and a comparator U2; wherein: The first power supply VS is simultaneously connected to one end of the first capacitor C1 and one end of the second resistor R2; the first power supply VS is also connected to the power supply pin vs of the current sensing amplifier and is grounded through the ground pin GND of the current sensing amplifier; the first pin IN- of the amplifier U1 is connected to one end of the first resistor R1 and is connected to the motor current signal, the second pin IN+ is connected to the other end of the first resistor R1 and is connected to the second power supply VCC, the third pin is connected to a stable voltage source providing a first reference voltage threshold, and the fourth pin is connected to the ADC module in the corresponding micro control unit and is connected to the first pin of the comparator U2; the warning voltage threshold pin ALERT of the comparator U2 is connected to the other end of the second resistor R2 and then connected to the first input port GPIO1 in the corresponding micro control unit; the over-limit alarm voltage threshold pin LIMIT1 of the comparator U2 is connected to one end of the third resistor R3; the latch voltage pin LATCH of the comparator U2 is connected to the second input port GPIO2 in the corresponding micro control unit; the other end of the third resistor R3 is grounded; the other end of the first capacitor C1 is grounded.

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