Headlamp position adjusting system based on ripple waves of brush direct current motor

Abstract

The invention provides a headlamp position adjusting system based on ripple waves of a brush direct-current motor. The headlamp position adjusting system comprises a whole vehicle height sensor and a steering angle sensor, wherein the whole vehicle height sensor and the steering angle sensor are used for collecting vehicle height and steering data in real time; the MCU control unit receives data of the whole vehicle height sensor and the rotation angle sensor and calculates the number of target rotation turns of the motor and the number of corresponding ripple pulses; the motor driving unit drives the brush direct current motor to operate; the current acquisition circuit acquires a ripple signal in the running current of the motor; the direct-current filter circuit filters direct-current components in the current signals; the ripple amplifying circuit amplifies the filtered alternating current ripple signal; and the ripple conversion circuit converts the amplified ripple signal into a pulse signal which can be identified by the MCU. The brush direct current motor is adopted to replace a traditional stepping motor, a drive circuit only needs a single full bridge, and the hardware cost is reduced by about 50%; a control circuit and a shielding wire harness in the motor are omitted, and the number of wire harnesses and connectors and the manufacturing cost are reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of automatic control of vehicle lighting systems, and in particular to a headlight position adjustment system based on ripple of a brushed DC motor. Background Art

[0002] With the increasing demand for automotive intelligence and safety, adaptive front-lighting systems (AFS) play an important role in vehicle dynamic lighting control. Traditional headlight position adjustment systems often use stepper motor drive solutions because they can accurately control the motor rotation angle through pulse signals, achieving precise adjustment of the height and direction of the headlights. However, stepper motor solutions have significant drawbacks: First, the stepper motor's drive circuit requires high-frequency current modulation (usually tens of kHz), resulting in prominent electromagnetic compatibility (EMC) issues and easily causing interference to on-board electronic equipment; second, stepper motors require a dual full-bridge drive circuit, which has high hardware costs; third, stepper motors have low energy efficiency and limited response speed, making it difficult to meet the dynamic adjustment requirements under complex working conditions.

[0003] To address cost issues, some solutions have attempted to replace stepper motors with conventional DC motors. However, traditional DC motor drive solutions typically rely on integrated position feedback circuitry (such as Hall sensors), which complicates the motor structure and increases costs. Furthermore, these solutions offer limited position control accuracy, enabling only fixed-gear adjustment and failing to meet the AFS system's requirement for continuous adjustment to any position. Furthermore, external sensors and complex wiring harnesses further increase system cost and failure rates. Summary of the Invention

[0004] In view of the defects in the prior art, the object of the present invention is to provide a headlight position adjustment system based on the ripple of a brushed DC motor.

[0005] According to the present invention, a headlight position adjustment system based on a brushed DC motor ripple is provided, comprising:

[0006] Vehicle height sensor and steering angle sensor: used to collect vehicle height and steering data in real time;

[0007] MCU control unit: receives data from the vehicle height sensor and the angle sensor and calculates the target number of motor rotations and the corresponding number of ripple pulses;

[0008] Motor drive unit: drives the brushed DC motor to operate;

[0009] Current acquisition circuit: collects the ripple signal in the motor running current;

[0010] DC filter circuit: filters out the DC component in the current signal;

[0011] Ripple amplifier circuit: amplifies the filtered AC ripple signal;

[0012] Ripple conversion circuit: converts the amplified ripple signal into a pulse signal that can be recognized by the MCU;

[0013] The MCU control unit determines the number of motor rotations by real-time counting pulse signals and controls the position of the headlight adjustment mechanism in a closed loop; the motor drive unit is connected to the current acquisition circuit; the current acquisition circuit is connected to the DC filter circuit; the DC filter circuit is connected to the ripple amplification circuit; the ripple amplification circuit is connected to the ripple conversion circuit; the MCU control unit is respectively connected to the ripple conversion circuit, the current acquisition circuit, and the DC filter circuit.

[0014] Preferably, the motor drive unit includes a full-bridge circuit, and the full-bridge circuit realizes forward and reverse control of the motor by switching the conduction state of FET drive tubes of different bridge arms.

[0015] Preferably, the current acquisition circuit includes a power resistor connected in series in the motor circuit, obtains the current signal by measuring the voltage difference across the resistor, and amplifies the signal using an operational amplifier.

[0016] Preferably, the DC filter circuit is composed of a capacitor to filter out the DC component in the signal to obtain an unsaturated ripple amplifier circuit.

[0017] Preferably, the ripple amplifier circuit adopts a common-emitter amplifier circuit, a capacitor is set at the input end to filter out high-frequency noise, and the ripple signal sensitivity is optimized by adjusting the static operating point and the amplification factor.

[0018] Preferably, the ripple conversion circuit includes a comparator and a hysteresis circuit, which converts the amplified ripple signal into a square wave pulse by setting a threshold voltage; when the input ripple signal voltage exceeds the threshold, the comparator outputs a high-level signal; when the input ripple signal voltage is lower than the threshold, it outputs a low-level signal to realize the conversion of the ripple signal into a pulse signal.

[0019] Preferably, the MCU control unit determines the motor stall status in real time based on the ripple period and current amplitude changes, and triggers a protection mechanism.

[0020] Preferably, the MCU control unit has a built-in parameter self-learning module, which dynamically calibrates the correspondence between the ripple number and the motor stroke according to the ambient temperature or motor aging.

[0021] Preferably, the MCU control unit controls the FET drive tube of the motor drive unit by adjusting the PWM duty cycle to achieve regulation of the motor speed.

[0022] Preferably, the system uses a linear step-down regulator to power the MCU, and an inductor-capacitor filter circuit is configured at the input and output ends respectively to obtain a stable power supply.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. This invention uses a brushed DC motor to replace the traditional stepper motor. The drive circuit only requires a single full-bridge (stepper motors require two full-bridges), reducing hardware costs by approximately 50%. The motor's internal control circuit and shielded wiring harness are eliminated, further reducing the number of wiring harnesses, connectors, and manufacturing costs. The brushed DC motor is driven by a 12V DC voltage, and the current modulation frequency is much lower than that of a stepper motor (stepper motors are tens of kHz), significantly reducing electromagnetic interference (EMC) and simplifying the EMC design of the entire lamp system.

[0025] 2. The DC motor of this invention is directly driven by voltage, making it significantly more efficient than the constant current modulation scheme of a stepper motor, reducing energy consumption by approximately 30%. The DC motor has a faster response speed and can dynamically adjust the headlight position in real time, improving driving safety. By using ripple counting technology to monitor the number of motor revolutions in real time and combining it with a closed-loop control algorithm, the headlight position can be precisely adjusted (with an accuracy of ±0.5°) and can be set to any position, breaking through the position and gear limitations of traditional DC motor solutions.

[0026] 3. The present invention has a built-in stall detection function, which can judge motor abnormalities in real time through ripple period and current changes to prevent hardware damage; the MCU control unit supports parameter self-learning and dynamically adjusts the threshold according to environmental changes such as temperature and aging to ensure long-term stability; the system does not require complex position sensors or built-in control modules, the hardware structure is simple, the failure rate is low, and maintenance costs are reduced; it is compatible with ordinary wiring harnesses and standard connectors, reducing supply chain complexity. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Other features, objects and advantages of the present invention will become more apparent upon reading the detailed description of non-limiting embodiments with reference to the following drawings:

[0028] Figure 1 It is a structural schematic diagram of the present invention;

[0029] Figure 2 This is a schematic diagram of the forward rotation of the motor of the present invention;

[0030] Figure 3 This is a schematic diagram of the motor reversal of the present invention;

[0031] Figure 4 This is a schematic diagram of the current acquisition and amplification circuit of the present invention;

[0032] Figure 5 This is a schematic diagram of the DC filtering, ripple amplification, and ripple conversion circuit of the present invention;

[0033] Figure 6 Schematic diagram of the frequency characteristics of the current acquisition circuit of the present invention;

[0034] Figure 7 This is a schematic diagram of the test waveform of the present invention when the amplitude is 4mV and the frequency is 200Hz;

[0035] Figure 8 Detailed design schematic diagram of the MCU power supply unit of the present invention;

[0036] Figure 9 This is a schematic diagram of the motor blocking waveform of the present invention. DETAILED DESCRIPTION

[0037] The present invention will be described in detail below with reference to specific embodiments. The following examples will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those skilled in the art, several changes and improvements can be made without departing from the scope of the present invention. These all fall within the scope of protection of the present invention.

[0038] Example 1:

[0039] Reference Figure 1 According to the present invention, a headlight position adjustment system based on a brushed DC motor ripple is provided, comprising:

[0040] Vehicle height sensor and steering angle sensor: used to collect vehicle height and steering data in real time;

[0041] MCU control unit: receives data from the vehicle height sensor and the angle sensor and calculates the target number of motor rotations and the corresponding number of ripple pulses;

[0042] Motor drive unit: drives the brushed DC motor to operate;

[0043] Current acquisition circuit: collects the ripple signal in the motor running current;

[0044] DC filter circuit: filters out the DC component in the current signal;

[0045] Ripple amplifier circuit: amplifies the filtered AC ripple signal;

[0046] Ripple conversion circuit: converts the amplified ripple signal into a pulse signal that can be recognized by the MCU;

[0047] The MCU control unit determines the number of motor rotations by real-time counting pulse signals and controls the position of the headlight adjustment mechanism in a closed loop; the motor drive unit is connected to the current acquisition circuit; the current acquisition circuit is connected to the DC filter circuit; the DC filter circuit is connected to the ripple amplifier circuit; the ripple amplifier circuit is connected to the ripple conversion circuit; the MCU control unit is respectively connected to the ripple conversion circuit, the current acquisition circuit, and the DC filter circuit.

[0048] The motor drive unit includes a full-bridge circuit, which switches the conduction state of the FET driver transistors in different bridge arms to achieve forward and reverse control of the motor. The current acquisition circuit includes a power resistor connected in series with the motor circuit. It obtains the current signal by measuring the voltage difference across the resistor and amplifies the signal using an operational amplifier.

[0049] The DC filter circuit, composed of capacitors, removes the DC component from the signal, resulting in an unsaturated ripple amplifier circuit. The ripple amplifier circuit uses a common-emitter amplifier circuit, with a capacitor at the input to filter out high-frequency noise. The ripple signal sensitivity is optimized by adjusting the static operating point and amplification factor.

[0050] The ripple conversion circuit includes a comparator and a hysteresis circuit, which converts the amplified ripple signal into a square wave pulse by setting a threshold voltage. When the input ripple signal voltage exceeds the threshold, the comparator outputs a high-level signal; when the input ripple signal voltage is lower than the threshold, it outputs a low-level signal, realizing the conversion of the ripple signal into a pulse signal.

[0051] The MCU control unit uses the ripple period and current amplitude changes to determine motor stall in real time and trigger protection mechanisms. The MCU also includes a built-in parameter self-learning module that dynamically calibrates the relationship between ripple and motor stroke based on ambient temperature and motor aging. The MCU controls the FET driver of the motor drive unit by adjusting the PWM duty cycle to regulate motor speed. The system uses a linear step-down regulator to power the MCU, with inductor-capacitor filtering circuits at the input and output to ensure a stable power supply.

[0052] Example 2:

[0053] This invention designs a drive solution based on a brushed DC ripple motor instead of the traditional stepper motor, providing a more economical solution for AFS systems. In addition to cost savings, brushed DC motors offer significant advantages over stepper motors in terms of motor efficiency and drive speed. Stepper motors typically have a current modulation frequency of tens of kHz, significantly impacting the EMC performance of the entire lamp. This solution, however, uses a standard 12V DC drive voltage, significantly improving EMC performance.

[0054] The vehicle's height sensor and angle sensor 1 collect relevant data and transmit it to the MCU control unit 12. Based on the collected data, the MCU control unit 12 calculates the number of motor revolutions required and the number of ripple pulses required. It then outputs motor control instructions to the motor drive unit 2, controlling the ripple DC motor to precisely operate the corresponding stroke, ensuring that the number of motor ripple pulses received matches the calculated ripple number. During motor operation, the motor drives the headlight adjustment mechanism 11 in horizontal or vertical motion. Simultaneously, during motor operation, the current acquisition circuit 3 collects the motor's operating current coupled with the AC ripple, ensuring that the number of ripples generated per motor revolution remains constant. The MCU control unit 12 uses the ADC module to collect the motor's real-time operating current, providing real-time information on motor stall, open circuit, and overcurrent conditions. Because the current signal collected by the current acquisition circuit 3 contains DC signals, the current acquisition circuit 5 filters out the DC component, leaving only the useful motor ripple signal. The motor ripple signal then passes through the ripple amplifier circuit 6 to amplify it, and finally, through the ripple conversion circuit, converts it into a pulse signal recognizable by the MCU. The MCU control unit 12 counts the number of pulse signals through the PWM capture port, and thus can indirectly know the number of revolutions of the motor through the number of ripple pulses.

[0055] Vehicle height sensors: These monitor changes in vehicle height relative to the road and are often used for headlight adjustment to prevent glare. They respond by adjusting headlight height in real time to varying driving conditions. Steering angle sensors: These measure steering wheel angle. This is crucial for the vehicle's dynamic stability control system. By measuring steering angle, the lighting control system can detect the driver's intentions and adjust the headlight angle as necessary to maintain safety.

[0056] Motor drive unit: A brushed DC motor is driven by a full-bridge circuit to drive a single motor coil.

[0057] Current acquisition circuit: This circuit indirectly measures current by measuring the voltage drop across a resistor. A low-value shunt resistor is selected to minimize power loss. The acquired voltage is amplified to facilitate analog-to-digital sampling by the MCU control unit 12.

[0058] Current AD sampling: The MCU control unit 12 converts the analog voltage signal into a digital signal that the MCU can recognize through the AD sampling module, thereby obtaining the driving current value of the motor.

[0059] DC filter circuit: removes the DC component from the signal and retains only the AC ripple component to prevent the saturation of the downstream ripple amplifier and improve the sensitivity to small signal changes.

[0060] Ripple amplifier circuit: further amplifies the motor's ripple signal to improve the sensitivity of ripple signal recognition.

[0061] Ripple conversion circuit: This circuit consists of a comparator, which is used to detect the difference between two voltages. When the input ripple signal voltage exceeds the threshold, the comparator outputs a high-level signal; when the input ripple signal voltage is lower than the threshold, it outputs a low-level signal to realize the conversion of ripple signal to pulse signal.

[0062] Software algorithm judgment: The MCU control unit 12 collects information such as the motor current value, ripple pulse frequency, etc., and uses a series of software algorithms to judge the motor running speed, the number of motor rotations, the motor running direction, and the motor stall condition.

[0063] Ripple Counter Unit: A dedicated ripple counter and motor travel management unit, responsible for controlling the motor's operating travel and learning ripple numbers. After receiving the motor, it needs to be calibrated to determine the number of ripples corresponding to the full travel of the brushed DC motor, thereby calculating the motor travel corresponding to a single ripple number.

[0064] MCU power supply unit: specifically responsible for the MCU's power supply system, generally powered by 5V voltage.

[0065] Headlight adjustment mechanism: The adjustment rod connected to the headlight housing is driven by a brushed DC motor and can move the reflector or the entire lamp assembly up and down, left and right to adjust the headlight position.

[0066] MCU control unit: It is the brain of the entire control system and is responsible for collecting vehicle sensor signals, motor current values, ripple pulse counts, calculating motor travel, controlling DC motor movement, motor stall detection, and motor speed determination.

[0067] When the DC motor is operating normally: the motor current remains stable and exhibits specific current ripple characteristics. The number of ripples generated by one rotation of the motor is fixed and is usually determined by the mechanical and electrical characteristics inside the motor. The range of the motor's movement is linearly related to the amount of current ripple in the motor. As long as the number of current ripples can be identified, the range of the motor's movement can be calculated, and the horizontal and vertical positions of the headlights can be determined. Abnormal changes: When the motor encounters an obstacle or is clamped by a foreign object, the movement of the motor is hindered, which will cause a significant change in the current, usually manifested as a sudden increase in current or a change in the ripple frequency. These characteristics can be used to accurately control the ripple DC motor, including the motor's movement position.

[0068] Based on the above motor characteristics, a headlight position adjustment method based on the ripple of a brushed DC motor is designed. A high-power sampling resistor is connected in series in the working path of the drive motor. The voltage across the resistor is collected and amplified to obtain the DC current signal and ripple signal of the motor. The collected ripple signal is then processed to filter out the DC component and amplify the AC ripple component. The AC ripple component and DC current component are collected by the MCU. Finally, the ripple component and current component are processed and calculated to achieve headlight position adjustment.

[0069] Motor drive unit: refer to Figure 2 and Figure 3 By simultaneously turning on the blue or red dashed FET driver transistors, the motor's forward and reverse rotation can be controlled. When switches Q1 / Q4 are on and switches Q2 / Q3 are off, the current flows from VM → Q1 → motor → Q4 → GND, achieving forward rotation of the motor. When switches Q2 / Q3 are on and switches Q1 / Q4 are off, the current flows from VM → Q2 → motor → Q3 → GND, achieving reverse rotation of the motor. MCU control unit 12 can also control the motor's speed by applying PWM with different duty cycles to the FET driver transistors.

[0070] Current acquisition circuit: In order to realize the ripple acquisition, the current signal must be converted into a voltage signal. In the test, a 10mR high-power resistor is connected in series in the motor path to collect the working current of the motor. Because the directly sampled signal is small, the sampled signal including the DC component and the AC component needs to be amplified, and the DC part is collected by the MCU control unit 12. Figure 4 This is a current acquisition and amplifier circuit. When the motor current passes through power resistor R222, a voltage difference is generated across resistor R222. The positive electrode of the voltage passes through current-limiting resistor R225 and is connected to the non-inverting terminal of the signal amplifier. At the same time, the positive electrode of the voltage passes through current-limiting resistor R224 and is connected to the inverting terminal of the signal amplifier. The amplification factor of this circuit is: Uo = Ui * R250 * R224 + R226 / R224 * (R225 + R250). You can select appropriate parameters and adjust the amplification factor according to project requirements.

[0071] DC filtering, ripple amplification, ripple conversion circuit: the entire complete circuit is as follows Figure 5. The signal amplified by the current acquisition circuit passes through the DC filter circuit, which is composed of only one capacitor C1 to filter out the DC component in the signal. The ripple secondary amplifier circuit is composed of a common-emitter amplifier circuit. Capacitors C1 and C2 are added to the input end of the signal. The capacitor cannot be too large, generally at the nF level, and mainly filters out the useless high-frequency components of the AC component ripple signal, which is generally below a few hundred Hz. R1, R7, R3, R8, and Q1 determine the static operating point and amplification factor of the amplifier circuit. The circuit amplifying transistor of the present invention adopts a DC gain range of 250 to 600 according to the manual. The static operating point is roughly estimated as follows. The static operating point setting is more appropriate, and the following test waveform can be checked.

[0072]

[0073] I c =βI b =1.57mA

[0074] U CE =5-I c (R3+R8)≈1.8V

[0075] Frequency characteristics of the current acquisition circuit: When the circuit is simulated using simulation software from -40 degrees to 100 degrees and the frequency is from 100Hz to 10khz, the frequency characteristics of the ripple detection circuit that is finally debugged are as follows: Figure 6 From the frequency characteristic simulation diagram, we can see that the ripple detection circuit has better characteristics at a low frequency of 10Khz and is more suitable for ripple collection of several hundred Hz.

[0076] Secondary DC filtering: further DC filtering of the signal in the ripple secondary amplifier circuit.

[0077] Ripple Conversion Circuit: The amplified signal after the transistor is applied to a 2.5V DC voltage, which serves as the inverting input of the comparator. R4 and R5 divide the voltage to generate a 2.5V DC voltage. C8 and C9 filter high-frequency components to prevent subsequent circuits from misinterpreting it as motor ripple. R6 and R9 form a hysteresis circuit, primarily to improve the circuit's immunity to interference, bias voltage, and noise. The threshold voltage is related to resistors R6 and R9. By appropriately reducing R9 or increasing R6, the difference between the positive and negative thresholds can be minimized, thereby enabling the detection of ripple signals with smaller peaks. Reducing R9 or increasing R6 presupposes that the circuit does not allow the DC voltages at the positive and negative terminals of the comparator to differ due to bias voltage, which can be caused by resistor value variations or ground drift. Testing has shown that a deviation of approximately 20mV to 40mV, or noise, can generate a pulse signal. In order to enhance the anti-interference ability of the circuit, R6 is selected as 33K and R9 is selected as 1K. The waveform at the positive input of the comparator should be a square wave with a high level of 2.574V and a low level of 2.426V. The threshold voltage of the comparator should be:

[0078] V=20mV~40mV+2.5V / 34K=94mV~114mV

[0079] The peak value of the amplified signal after the transistor should be guaranteed to be greater than 228mV, otherwise the ripple signal may be lost. When the analog input amplitude is 4mv and the frequency is 200Hz, 250Hz, 300Hz, 500Hz, 1khz, 1.5khz, 2khz, the peak value of the signal after the transistor amplification is about 280mV. At this time, the setting of the resistance values ​​of R6 and R9 can meet the circuit design requirements. The setting of the resistance values ​​of R6 and R9 can be adjusted according to the specific brushed DC motor. The resistance value of R9 can be appropriately reduced or the resistance value of R6 can be increased to improve the recognition sensitivity of ripple. The specific waveform is as follows Figure 7 shown.

[0080] MCU power supply unit: This module unit consists of three parts: input filter circuit, linear LDO, and output filter. This design uses linear buck regulator 2 as 5V voltage supply. These devices have a wide input voltage operation. The only thing to consider when designing these devices is input filter circuit 1 and output filter circuit 2. This solution recommends using a combination of 4.7μF and 100nf input capacitors and inductor L26 for filtering to ensure that the input of the LDO chip meets the requirements of the LDO chip; output capacitors 2.2μF and 100μF ensure the stability of the output 5V voltage. Figure 8 Design a detailed schematic diagram for the MCU power supply unit.

[0081] MCU control unit:

[0082] Each revolution of the motor generates a fixed amount of current ripple, N. The travel of a DC motor is linearly related to the amount of current ripple. By identifying the amount of current ripple, the travel of the headlight can be calculated, and thus the headlight's height position. The MCU calculates the number of ripples during the motor's travel and sends control instructions to the motor drive unit, controlling the brushed DC motor. The MCU also reads back the number of ripple pulses, forming a closed-loop control system with indirect position detection.

[0083] Motor stall detection: The MCU control unit combines the ripple period and the motor current to determine whether the motor is in a stalled state. If the motor is stalled, the ripple period becomes longer and the motor current becomes larger, such as Figure 9 waveform.

[0084] Motor parameters are affected by various environmental factors, such as temperature fluctuations and motor aging. Using a single, fixed relationship between ripple quantity, ripple period, and current detection threshold can easily cause headlight position deviation. The MCU control unit can self-learn motor parameters, allowing them to revise according to changes in the external environment. During motor position self-learning, the initial parameters can be used as a reference value and stored in the MCU, serving as the basis for subsequent parameter calculations. Each subsequent motor operation will calculate the latest motor parameters, allowing for timely adjustment of motor parameters based on changing external operating conditions.

[0085] Stepper motors are highly favored for adjusting the height of headlights due to their higher precision. However, stepper motor drive solutions are costly and can introduce EMC issues. Conventional DC motor drive solutions lack position feedback, requiring built-in control circuitry within the DC motor unit and external control signals for control. Furthermore, the limited number of height settings restricts their use cases. This invention, by identifying the ripple count of a brushed DC motor, can determine the current operating position of the motor in real time, enabling arbitrary position control of the DC motor solution.

[0086] The main advantages of brushed DC motors over stepper motors are as follows: Brushed DC motors have low EMC interference and can be directly controlled with ordinary wiring harnesses, avoiding the increased costs associated with shielded wiring harnesses; DC motors only require a single full-bridge drive, while stepper motors require two full-bridge drives, halving the drive cost; the response speed of DC motors is greater than that of stepper motors due to two motor characteristics; stepper motors are driven by constant current modulation of the A / B coils, while DC motors are directly driven by the supply voltage. In terms of energy efficiency, DC motors are far more efficient than stepper motors.

[0087] The main advantages of DC motors over conventional solutions are as follows: The motor is a brushless DC motor only, eliminating the built-in control circuitry within the DC motor unit and offering cost advantages. The DC motor solution can achieve arbitrary position control, while conventional solutions offer limited position and gear control. The number of wiring harnesses and connector pins is further reduced, eliminating the motor gear control signal and further reducing costs. While the accuracy of an automatic headlight height adjustment system based on a brushed DC motor with ripple counting may be slightly lower than that of a stepper motor system in some cases, it offers more comprehensive performance advantages in terms of response speed, cost-effectiveness, and energy efficiency. Therefore, this solution can be an alternative to stepper motor systems, providing a more economical solution for headlight position and height adjustment applications.

[0088] Those skilled in the art may understand this embodiment as a more specific description of Embodiment 1.

[0089] Those skilled in the art will appreciate that, in addition to implementing the system and its various devices, modules, and units provided by the present invention in purely computer-readable program code, it is entirely possible to implement the same functions of the system and its various devices, modules, and units provided by the present invention in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, and embedded microcontrollers by logically programming the method steps. Therefore, the system and its various devices, modules, and units provided by the present invention can be considered a hardware component, and the devices, modules, and units included therein for implementing various functions can also be considered as structures within the hardware component; the devices, modules, and units for implementing various functions can also be considered as both software modules implementing the method and structures within the hardware component.

[0090] The above describes specific embodiments of the present invention. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art may make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. The embodiments of this application and the features in the embodiments may be combined with each other in any manner unless there is a conflict.

Claims

1. A headlight position adjustment system based on brushed DC motor ripple, characterized in that: include: Vehicle height sensor and steering angle sensor: used to collect vehicle height and steering data in real time; MCU control unit: receives data from the vehicle height sensor and the angle sensor and calculates the target number of motor rotations and the corresponding number of ripple pulses; Motor drive unit: drives the brushed DC motor to operate; Current acquisition circuit: collects the ripple signal in the motor running current; DC filter circuit: filters out the DC component in the current signal; Ripple amplifier circuit: amplifies the filtered AC ripple signal; Ripple conversion circuit: converts the amplified ripple signal into a pulse signal that can be recognized by the MCU; The MCU control unit determines the number of motor rotations by real-time counting pulse signals and controls the position of the headlight adjustment mechanism in a closed loop; the motor drive unit is connected to the current acquisition circuit; the current acquisition circuit is connected to the DC filter circuit; the DC filter circuit is connected to the ripple amplification circuit; the ripple amplification circuit is connected to the ripple conversion circuit; the MCU control unit is respectively connected to the ripple conversion circuit, the current acquisition circuit, and the DC filter circuit.

2. The headlight position adjustment system based on brushed DC motor ripple according to claim 1, characterized in that: The motor drive unit includes a full-bridge circuit, which realizes forward and reverse rotation control of the motor by switching the conduction state of FET drive tubes of different bridge arms.

3. The headlight position adjustment system based on brushed DC motor ripple according to claim 1, characterized in that: The current acquisition circuit includes a power resistor connected in series in the motor circuit, obtains a current signal by measuring the voltage difference across the resistor, and amplifies the signal using an operational amplifier.

4. The headlight position adjustment system based on brushed DC motor ripple according to claim 1, characterized in that: The DC filter circuit is composed of capacitors, which filters out the DC component in the signal to obtain an unsaturated ripple amplifier circuit.

5. The headlight position adjustment system based on brushed DC motor ripple according to claim 1, characterized in that: The ripple amplifier circuit adopts a common-emitter amplifier circuit, a capacitor is set at the input end to filter high-frequency noise, and the ripple signal sensitivity is optimized by adjusting the static operating point and the amplification factor.

6. The headlight position adjustment system based on brushed DC motor ripple according to claim 1, characterized in that: The ripple conversion circuit includes a comparator and a hysteresis circuit, which converts the amplified ripple signal into a square wave pulse by setting a threshold voltage; when the input ripple signal voltage exceeds the threshold, the comparator outputs a high-level signal; when the input ripple signal voltage is lower than the threshold, it outputs a low-level signal, thereby realizing the conversion of the ripple signal into a pulse signal.

7. The headlight position adjustment system based on brushed DC motor ripple according to claim 1, characterized in that: The MCU control unit determines the motor stall status in real time based on the ripple period and current amplitude changes, and triggers a protection mechanism.

8. The headlight position adjustment system based on brushed DC motor ripple according to claim 1, characterized in that: The MCU control unit has a built-in parameter self-learning module, which dynamically calibrates the corresponding relationship between the ripple number and the motor stroke according to the ambient temperature or motor aging.

9. The headlight position adjustment system based on brushed DC motor ripple according to claim 1, characterized in that: The MCU control unit controls the FET drive tube of the motor drive unit by adjusting the PWM duty cycle to achieve regulation of the motor speed.

10. The headlight position adjustment system based on brushed DC motor ripple according to claim 1, characterized in that: The system uses a linear step-down regulator to power the MCU, and an inductor-capacitor filter circuit is configured at the input and output ends to obtain a stable power supply.

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