Lead screw transmission control method for vehicle-mounted refrigerator drawer

Abstract

The invention discloses a lead screw transmission control method for a vehicle-mounted refrigerator drawer, and relates to the technical field of intelligent control. The lead screw transmission control method of the vehicle-mounted refrigerator drawer comprises the following steps: detecting a pulse signal generated by rotation of a rotor through a Hall sensor of a brushless direct current actuator; the number of rotation turns of the brushless direct current actuator is calculated based on Hall pulse signal counting, and the real-time displacement of the drawer is calculated based on the corresponding relation between the number of rotation turns and the screw pitch of the lead screw; acquiring a speed change rate based on the real-time displacement; in response to the fact that the speed change rate is larger than a first change rate threshold value, sharp closing is triggered. The speed change rate is calculated by detecting the pulse signal generated by the Hall sensor, and the sharp closing is triggered when the speed change rate exceeds the threshold value, so that the safety and the user experience are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of intelligent control, in particular to a lead screw transmission control method for a drawer of a vehicle refrigerator. BACKGROUND

[0002] To improve the travel experience of vehicle passengers, current vehicle owners will install a vehicle refrigerator in the vehicle they purchase to facilitate the driver's refrigeration operation on the items. The vehicle refrigerator commonly adopts a drawer pull-out structure. The control method of the drawer is mostly in a semi-automatic control mode, that is, the vehicle system is allowed to control the opening and closing of the drawer while the user is allowed to push and pull the drawer to achieve opening and closing.

[0003] However, the control method of the prior art has the following disadvantages:

[0004] When the user pushes the drawer with force to quickly close it, the system cannot recognize the large pushing force and the fast acceleration generated thereby, resulting in a hard collision between mechanical components, increasing the risk of wear and tear, and even possibly causing damage to internal components and / or shortening the service life.

[0005] When the user tries to quickly close the drawer, the system does not automatically respond to the action of accelerating the closing. Instead, it may continue to run at the preset speed, resulting in no timely feedback of the user's operation intention and affecting the use experience. SUMMARY

[0006] To solve the above problems, the present application provides a lead screw transmission control method for a drawer of a vehicle refrigerator, comprising the following steps:

[0007] Detecting a pulse signal generated by rotation of a rotor of a brushless DC actuator through a Hall sensor of the brushless DC actuator;

[0008] Calculating the number of rotations of the brushless DC actuator based on the Hall pulse signal count and calculating the real-time displacement of the drawer based on the corresponding relationship between the number of rotations and the pitch of the lead screw;

[0009] Obtaining a speed change rate based on the real-time displacement; in response to the speed change rate being greater than a first change rate threshold, triggering an emergency closing.

[0010] Wherein, in response to the real-time displacement, it is determined that the drawer is located at a full-closed position; a continuous current without commutation is applied to the brushless DC actuator to achieve self-locking.

[0011] Wherein, in response to the real-time displacement, it is determined that the drawer is located between the full-closed position and the full-open position to perform a blocked execution determination; the blocked execution determination comprises the following steps:

[0012] Real-time monitoring of the current of the brushless DC actuator;

[0013] in response to the current rate of change being greater than a current rate of change threshold and the speed rate of change being greater than a second rate of change threshold;

[0014] controlling the brushless DC actuator to reverse motion back up.

[0015] wherein, in response to the real-time displacement amount determining that the drawer is located at a fully closed position or a fully open position, the obstruction determination is disabled.

[0016] wherein, the drawer starting is based on a motor soft start implementation; the motor soft start includes the following steps:

[0017] in response to the drawer moving from a first position to a second position;

[0018] the brushless DC actuator starts at an initial speed lower than a rated speed, and accelerates to the rated speed after a first distance;

[0019] in response to the distance of the drawer from the second position being the first distance; controlling the brushless DC actuator to decelerate from the rated speed, and when reaching the second position, the speed is reduced to zero.

[0020] wherein, in response to first installation or replacement of the drawer, self-learning calibration is performed; the self-learning calibration includes the following steps:

[0021] controlling the drawer to move from a fully closed position to a fully open position, recording a first total number of Hall pulses, and obtaining a first stroke based on the first total number of Hall pulses;

[0022] controlling the drawer to return from the fully open position to the fully closed position, recording a second total number of Hall pulses, and obtaining a second stroke based on the second total number of Hall pulses;

[0023] in response to the sum of the first stroke and the second stroke being between a minimum calibration stroke and a maximum calibration stroke, calculating an actual stroke and storing it.

[0024] wherein, in response to the absolute value of the difference between the first stroke and the second stroke being less than a stroke difference threshold, an actual stroke is calculated and stored.

[0025] wherein, further comprising overvoltage protection, the overvoltage protection includes the following steps:

[0026] real-time monitoring of the voltage of the brushless DC actuator;

[0027] in response to the voltage being greater than a first voltage and the duration exceeding a first time threshold, the brushless DC actuator enters an overvoltage protection mode, the motor stops running and reports an overvoltage fault;

[0028] In response to the voltage being less than a second voltage and the duration exceeding a second time threshold, the brushless DC actuator exits the overvoltage protection mode, the motor resumes operation and the overvoltage fault is cleared.

[0029] The method further comprises an under-voltage protection, which comprises the following steps:

[0030] The voltage of the brushless DC actuator is monitored in real time.

[0031] In response to the voltage being less than a third voltage and the duration exceeding a third time threshold, the brushless DC actuator enters the under-voltage protection mode, the motor stops operation and an under-voltage fault is reported.

[0032] In response to the voltage being greater than a fourth voltage and the duration exceeding a fourth time threshold, the brushless DC actuator exits the under-voltage protection mode, the motor resumes operation and the under-voltage fault is cleared.

[0033] The method further comprises a hardware over-voltage protection, which comprises the following steps:

[0034] The voltage of the brushless DC actuator is monitored in real time.

[0035] If the voltage is greater than a fifth voltage, the motor stops operation.

[0036] Compared with the prior art, the application has at least one of the following beneficial effects:

[0037] 1. The speed change rate is calculated by detecting the pulse signal generated by the Hall sensor, and the emergency shutdown is triggered when the speed change rate exceeds the threshold, thereby improving the safety.

[0038] 2. The self-locking is realized by applying a continuous current to the brushless DC actuator, thereby enhancing the stability of the drawer in the closed state.

[0039] 3. The blocked determination method based on the current and the speed change rate can make the actuator move backward in the reverse direction when an abnormality is detected, thereby reducing the damage caused by the locked rotor.

[0040] 4. The motor soft start strategy can ensure that the drawer accelerates smoothly to the rated speed and slows down to stop when approaching the target position, thereby improving the operation smoothness. BRIEF DESCRIPTION OF DRAWINGS

[0041] In order to more clearly illustrate the technical solutions in the embodiments of the application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor.

[0042] wherein:

[0043] Figure 1 A flowchart of a screw drive control method of a drawer of a vehicle-mounted refrigerator according to an embodiment of the present application is provided.

[0044] Figure 2 A schematic diagram of an emergency closing principle according to an embodiment of the present application is provided.

[0045] Figure 3 A schematic diagram of a blocked determination principle according to an embodiment of the present application is provided.

[0046] Figure 4 A schematic diagram of a self-learning calibration principle according to an embodiment of the present application is provided.

[0047] Figure 5 A flowchart of a voltage protection according to an embodiment of the present application is provided. DETAILED DESCRIPTION

[0048] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. It can be understood that the specific embodiments described herein are only used to explain the present application, but not to limit the present application. In addition, it should be noted that, for the convenience of description, only the parts related to the present application are shown in the drawings, but not all the structures. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative labor fall within the scope of the present application.

[0049] The terms "first", "second", and the like in the present application are used to distinguish different objects, but not to describe a specific order. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device including a series of steps or units is not limited to the listed steps or units, but optionally includes other steps or units not listed or optionally includes other steps or units inherent to the process, method, product or device.

[0050] In this document, reference to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the application. The appearances of the phrase "in an embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are they necessarily mutually exclusive of one another. It is expressly understood that the embodiments described herein are merely examples from a multitude of possible embodiments, which can be readily adapted to a specific application.

[0051] The prior art often lacks real-time monitoring and response mechanism for speed change rate when controlling the drawer drive of a vehicle-mounted refrigerator, which leads to the system being unable to identify abnormal situations and make corresponding adjustments in time when the user quickly pushes or pulls the drawer or encounters obstacles, thereby possibly increasing the risk of injury, damaging mechanical parts due to hard collision, and poor user experience. In view of this, the present application provides a lead screw drive control method for a drawer of a vehicle-mounted refrigerator, which calculates the speed change rate by detecting the pulse signal generated by the Hall sensor, and triggers an emergency shutdown when the speed change rate exceeds the threshold, thereby improving safety.

[0052] As shown in Figure 1 , Figure 1 The flowchart of the lead screw drive control method for a drawer of a vehicle-mounted refrigerator provided by an embodiment of the present application includes the following steps:

[0053] S1: A controller and a Hall sensor are arranged inside the brushless DC actuator; the pulse signal generated by the rotor rotation is detected by the Hall sensor of the brushless DC actuator; for example, in this embodiment, a three-phase Hall sensor is integrated inside the brushless DC actuator, which is uniformly distributed at 120°, and the change of the rotor magnetic pole is captured in real time. When the motor rotates, the rotor magnet triggers the Hall element to generate a square wave pulse, for example, 6 pulses per revolution; it should be noted that the present application does not limit the number of Hall sensors and the corresponding relationship between the number of rotor revolutions and the number of pulses.

[0054] The Hall sensor is based on non-contact detection to avoid mechanical wear, and compared with a mechanical limit switch, it improves the usage frequency; the Hall sensor uses gallium arsenide material, which has higher adaptability to low temperature environment than an optical encoder.

[0055] S2: The number of revolutions of the brushless DC actuator is calculated based on the Hall pulse signal count, and the real-time displacement of the drawer is calculated based on the corresponding relationship between the number of revolutions and the lead screw pitch; the controller accumulates the number of Hall pulses, for example, the lead screw pitch is 4mm, and the displacement per pulse can be obtained as 4mm / 6≈0.67mm based on 6 pulses per revolution of the motor; that is, each pulse represents the real-time displacement of the drawer as 0.67mm; the real-time displacement of the drawer is obtained by corresponding pulse number, without the need to install a position sensor, thereby reducing the cost.

[0056] S3: The speed change rate is obtained based on the real-time displacement; in response to the speed change rate being greater than a first change rate threshold, an emergency shutdown is triggered; the triggering steps of the emergency shutdown function are described in detail as follows:

[0057] When the user pushes the drawer with force to quickly close it, the Hall sensor continuously monitors the pulse signal generated by the rotor rotation;

[0058] The real-time displacement of the drawer is calculated based on the pulse signal, and the speed change rate is determined based on the change of the displacement with time;

[0059] If the rate of change of speed exceeds the preset first rate of change threshold, the system will automatically trigger the emergency closing function to quickly stop the drawer's movement and prevent injury caused by closing too quickly.

[0060] It should be clarified that this application does not limit the specific size of the first rate of change threshold; different rate of change thresholds can be set based on different drawer components.

[0061] like Figure 2 As shown, Figure 2 This is a schematic diagram of the emergency shut-off principle provided in an embodiment of this application; the following is a description of... Figure 2 Analysis:

[0062] The user pushes the drawer, causing the lead screw to rotate and the nut to shift, which in turn causes the brushless motor rotor to rotate.

[0063] Hall effect sensors detect changes in magnetic fields and output pulse sequences;

[0064] The controller calculates the change in the drawer's position, i.e., the displacement increment ΔP = current pulse count - previous pulse count;

[0065] The time interval Δt = 10ms; it should be noted that in this embodiment, 10ms is a fixed sampling period; in other embodiments, the time interval of the fixed sampling period can be selected in other ways, and there is no limitation on it.

[0066] Then, obtain the rate of change of speed based on the unique increment and time interval; determine whether to trigger emergency shutdown based on the magnitude of the rate of change of speed and the first rate of change threshold.

[0067] In summary, the lead screw drive control method for the car refrigerator drawer in this embodiment includes the following steps: detecting the pulse signal generated by the rotor rotation using a Hall sensor of the brushless DC actuator; calculating the number of rotations of the brushless DC actuator based on the Hall pulse signal count; calculating the real-time displacement of the drawer based on the correspondence between the number of rotations and the lead screw pitch; obtaining the speed change rate based on the real-time displacement; and triggering an emergency close in response to the speed change rate exceeding a first speed change rate threshold. By detecting the pulse signal generated by the Hall sensor and calculating the speed change rate, and triggering an emergency close when the speed change rate exceeds the threshold, safety and user experience are improved.

[0068] The lead screw drive control method for the drawer of the vehicle refrigerator responds to the real-time displacement to determine that the drawer is in the fully closed position; a continuous current without commutation is applied to the brushless DC actuator to achieve self-locking.

[0069] The brushless DC actuator uses a Hall sensor inside to detect the pulse signal generated by the rotor rotation and calculates the real-time displacement of the drawer based on the pulse signal.

[0070] In response to the calculated real-time displacement amount matching the preset full-close position, it is determined that the drawer has reached the full-close position.

[0071] In order to ensure that the drawer remains stable and immobile in the closed state, the system applies a continuous current without commutation to the brushless DC actuator; such continuous current causes the motor to generate sufficient holding torque to prevent any external force from easily moving the drawer.

[0072] Different current sizes correspond to different sizes of self-locking force, for example, 80mA current corresponds to 30N self-locking force, 120mA current corresponds to 60N self-locking force, and 150mA current corresponds to 100N self-locking force; by adjusting the PWM (pulse width modulation) duty cycle, the current can be precisely controlled to change the size of the self-locking force.

[0073] By applying a continuous current without commutation to achieve self-locking, it can effectively prevent the drawer from being accidentally opened due to slight collisions or accidental external forces, especially in the case of a vibrating environment that may occur during vehicle driving; even when subjected to certain external forces, the drawer can be stably maintained in the closed state due to the strong holding torque provided by the brushless DC actuator, and will not be easily moved, thereby improving the stability of the entire system.

[0074] In response to the real-time displacement amount determining that the drawer is located between the full-close position and the full-open position, a blocked determination is performed; the real-time displacement amount of the drawer is calculated based on the pulse signals generated by the rotation of the rotor detected by the Hall sensor inside the brushless DC actuator; if the real-time displacement amount determines that the drawer is located between the full-close position and the full-open position, the blocked determination mechanism is activated. The blocked determination includes the following steps:

[0075] The current of the brushless DC actuator is monitored in real time; at the same time, the speed change rate is obtained based on the continuously recorded real-time displacement amount data.

[0076] In response to the current change rate being greater than the current change rate threshold and the speed change rate being greater than the second change rate threshold; it should be noted that the application does not limit the specific values of the current change rate threshold and the second change rate threshold; but in order to distinguish the effectiveness of the blocked determination and the emergency closing function, the second change rate threshold should be less than the first change rate threshold.

[0077] The brushless DC actuator is controlled to move in reverse to retreat; if the drawer is blocked during opening, it retreats a first retreat distance close to the full-close position to implement the anti-collision function; if the drawer is blocked during closing, it retreats a second retreat distance close to the full-open position to implement the anti-pinch function; the sizes of the first retreat distance and the second retreat distance can be equal or not equal, and no limitation is made in this regard.

[0078] The drawer can respond in time when encountering an obstacle, avoiding mechanical damage or user injury caused by continuing to push. Especially during the closing process of the drawer, it can effectively prevent accidents such as pinching hands; the blocked determination mechanism makes the user not worry about the blocking problem that may be encountered during use, improving the convenience and comfort of use. Even if the drawer path is accidentally blocked when placing an object, the system can automatically adjust and reduce user concerns.

[0079] As shown in Figure 3 , Figure 3 The blocked determination principle diagram provided by an embodiment of the present application; in response to the real-time displacement amount, it is determined whether the drawer is at the fully closed position or the fully open position, and the blocked determination is disabled; at the fully closed position, the system applies a continuous current without commutation to the brushless DC actuator to realize the self-locking function, ensuring that the drawer is stably kept closed; at the fully open position, only the current state is maintained without additional action.

[0080] It should be clear that the drawer movement has inertia, and the fully closed position A and the fully open position B in the blocked determination are a certain stroke; the anti-collision and anti-pinch determination region is between the fully closed position and the fully open position; the total stroke is the anti-collision and anti-pinch determination region + the fully closed position A + the fully open position B; it should be clear that the present application does not limit the stroke size of the anti-collision and anti-pinch determination region, the fully closed position A and the fully open position B.

[0081] The drawer starts based on motor soft start; the motor soft start includes the following steps:

[0082] In response to the movement of the drawer from the first position to the second position; for example, the first position is the fully closed position, and the second position is the fully open position.

[0083] The brushless DC actuator starts at an initial speed lower than the rated speed, and accelerates to the rated speed after a first distance; after starting, the motor gradually accelerates to its rated speed after a predetermined first distance. This allows the drawer to move slowly at the beginning, avoiding sudden impact forces that can damage mechanical components and reduce noise.

[0084] In response to the distance of the drawer from the second position being the first distance; control the brushless DC actuator to decelerate from the rated speed, and the speed drops to zero when it reaches the second position; when the drawer approaches the fully open position, i.e. the remaining distance from the fully open position is the first distance, the system starts to control the brushless DC actuator to decelerate.

[0085] Finally, when the drawer reaches the fully open position, the motor speed drops to zero, achieving a smooth and precise stop, preventing any additional displacement or impact that may be caused by inertia.

[0086] By adopting the soft start technology, the risk of accidental injury caused by rapid start or stop is reduced; the slow start and gradual acceleration mode helps to reduce the wear and tear between mechanical parts, especially for precision components such as lead screws, nuts, etc., which can significantly prolong their service life.

[0087] As shown in Figure 4 , Figure 4 The principle diagram of self-learning calibration provided by an embodiment of the present application; self-learning calibration is performed in response to the first installation or replacement of the drawer; the self-learning calibration includes the following steps:

[0088] Calibration step 1: control the drawer to move from the fully closed position to the fully open position, record the total number of first Hall pulses, and obtain the first stroke based on the relationship between the total number of first Hall pulses and the lead screw pitch.

[0089] Calibration step 2: control the drawer to return from the fully open position to the fully closed position, record the total number of second Hall pulses, and obtain the second stroke based on the relationship between the total number of second Hall pulses and the lead screw pitch.

[0090] In response to the sum of the first stroke and the second stroke being between the minimum calibration stroke and the maximum calibration stroke, the actual stroke is calculated and stored; if the sum of the first stroke and the second stroke is less than the minimum calibration stroke or greater than the maximum calibration stroke, it is not stored and an error is reported.

[0091] In response to the absolute value of the difference between the first stroke and the second stroke being less than the stroke difference threshold, the actual stroke is calculated and stored; if the absolute value of the difference is less than the stroke difference threshold, it indicates that the consistency of the two measurements is good, and the system will take the average of the two as the actual stroke value and store it for subsequent use; if the absolute value of the difference is not less than the stroke difference threshold, the system can prompt a fault or re-calibrate to prevent the control accuracy from being affected by excessive error.

[0092] It should be clear that the present application does not limit the specific values of the minimum calibration stroke, the maximum calibration stroke and the stroke difference threshold.

[0093] The introduction of minimum and maximum calibration stroke limits, as well as stroke difference threshold judgment mechanism, can effectively exclude abnormal data and prevent system misjudgment from causing control failure; by measuring in both directions and taking the average, the error that may exist in a single measurement is effectively eliminated, thereby improving the measurement accuracy of the drawer stroke.

[0094] The lead screw transmission control method of the vehicle-mounted refrigerator drawer further includes voltage protection; the voltage protection includes overvoltage protection, undervoltage protection and hardware overvoltage protection; as shown in Figure 5 , Figure 5 The flowchart of voltage protection provided by an embodiment of the present application.

[0095] The overvoltage protection includes the following steps:

[0096] monitoring the voltage of the brushless DC actuator in real time;

[0097] In response to the voltage being greater than the first voltage and the duration exceeding the first time threshold, the brushless DC actuator enters an overvoltage protection mode, the motor stops running and reports an overvoltage fault; in this embodiment, the first voltage is 18V and the first time threshold is 1s; that is, the voltage exceeds 18V and the duration exceeds 1s, and the overvoltage protection mode is entered.

[0098] In response to the voltage being less than the second voltage and the duration exceeding the second time threshold, the brushless DC actuator exits the overvoltage protection mode, the motor resumes running and the overvoltage fault is cleared; in this embodiment, the second voltage is 17V and the second time threshold is 1s; that is, the voltage is less than 17V and the duration exceeds 1s, and the overvoltage protection mode is exited.

[0099] The under-voltage protection includes the following steps:

[0100] monitoring the voltage of the brushless DC actuator in real time;

[0101] In response to the voltage being less than the third voltage and the duration exceeding the third time threshold, the brushless DC actuator enters an under-voltage protection mode, the motor stops running and reports an under-voltage fault; in this embodiment, the third voltage is 7.5V and the third time threshold is 1s; that is, the voltage is less than 7.5V and the duration exceeds 1s, and the under-voltage protection mode is entered.

[0102] In response to the voltage being greater than the fourth voltage and the duration exceeding the fourth time threshold, the brushless DC actuator exits the under-voltage protection mode, the motor resumes running and the under-voltage fault is cleared; in this embodiment, the fourth voltage is 8.5V and the fourth time threshold is 1s; that is, the voltage exceeds 8.5V and the duration exceeds 1s, and the under-voltage protection mode is exited.

[0103] The hardware overvoltage protection includes the following steps:

[0104] monitoring the voltage of the brushless DC actuator in real time;

[0105] If the voltage is greater than the fifth voltage, the motor stops running; in this embodiment, the fifth voltage is 30V, that is, the voltage exceeds 30V, regardless of the duration, the hardware overvoltage protection mechanism is immediately started, the motor is forced to stop running, and permanent damage caused by extremely high voltage is prevented.

[0106] In this embodiment, the first time threshold, the second time threshold, the third time threshold and the fourth time threshold are all 1s; the application does not limit that the time thresholds must be equal, in other embodiments, the time thresholds can be additionally selected, and no limitation is made on this.

[0107] In the embodiment, the first voltage is 18V, the second voltage is 17V, the third voltage is 7.5V, the fourth voltage is 8.5V, and the fifth voltage is 30V; the application does not limit the specific size of the voltage; but the priority of the size of the voltage is:

[0108] The fifth voltage > the first voltage > the second voltage > the fourth voltage > the third voltage.

[0109] By implementing a comprehensive voltage protection strategy, damage to equipment caused by voltage abnormalities can be effectively prevented, ensuring the long-term stability and reliability of the system; appropriate voltage protection can avoid the impact of excessively high or low voltage on the motor and other electronic components, thereby prolonging their service life.

[0110] In several embodiments provided in the application, it should be understood that the disclosed methods and devices can be implemented in other ways. For example, the device embodiments described above are only illustrative, for example, the division of the modules or units is only a logical function division, and actual implementation can have another division manner, for example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed.

[0111] The units described as separate components can or can not be physically separated, and the components displayed as units can or can not be physical units, that is, they can be located in one place, or they can be distributed on multiple network units. According to actual needs, part or all of the units can be selected to achieve the purpose of the embodiment.

[0112] In addition, the functional units in each embodiment of the application can be integrated in one processing unit, or each unit can be physically present alone, or two or more units can be integrated in one unit. The integrated unit can be realized in the form of hardware or in the form of a software functional unit.

[0113] The above is only an embodiment of the application, and does not limit the patent scope of the application, and any equivalent structure or equivalent process transformation using the content of the specification and drawings, or direct or indirect application in other related technical fields, are also included in the patent protection scope of the application.

Claims

1. A screw drive control method for a car refrigerator drawer, characterized in that, Includes the following steps: The Hall sensor of the brushless DC actuator detects the pulse signal generated by the rotor rotation; The number of rotations of the brushless DC actuator is calculated based on Hall pulse signal counting, and the real-time displacement of the drawer is calculated based on the correspondence between the number of rotations and the lead screw pitch. The velocity change rate is obtained based on the real-time displacement; in response to the velocity change rate being greater than a first change rate threshold, an emergency shutdown is triggered.

2. The screw drive control method for a vehicle refrigerator drawer according to claim 1, characterized in that, In response to the real-time displacement, the drawer is determined to be in the fully closed position; a continuous current without commutation is applied to the brushless DC actuator to achieve self-locking.

3. The screw drive control method for a car refrigerator drawer according to claim 1, characterized in that, In response to the real-time displacement determination that the drawer is located between the fully closed and fully open positions, an obstruction determination is performed; the obstruction determination includes the following steps: Real-time monitoring of the current of the brushless DC actuator; In response to the current change rate being greater than a current change rate threshold and the velocity change rate being greater than a second change rate threshold; Control the brushless DC actuator to move in the reverse direction and retract.

4. The screw drive control method for a car refrigerator drawer according to claim 3, characterized in that, In response to the real-time displacement determination that the drawer is in the fully closed or fully open position, the obstruction determination is disabled.

5. The screw drive control method for a car refrigerator drawer according to claim 1, characterized in that, The drawer start is achieved based on a motor soft starter; the motor soft starter includes the following steps: In response to the drawer moving from the first position to the second position; The brushless DC actuator starts at an initial speed lower than the rated speed and accelerates to the rated speed after a first distance. In response to the drawer being at a distance from the second position equal to the first distance, the brushless DC actuator is controlled to decelerate from its rated speed until the speed drops to zero at the second position.

6. The screw drive control method for a car refrigerator drawer according to claim 1, characterized in that, A self-learning calibration is performed in response to the first installation or replacement of the drawer; the self-learning calibration includes the following steps: Control the drawer to move from the fully closed position to the fully open position, record the total number of first Hall pulses, and obtain the first stroke based on the total number of first Hall pulses; Control the drawer to return from the fully open position to the fully closed position, record the total number of second Hall pulses, and obtain the second stroke based on the total number of second Hall pulses; If the sum of the first travel and the second travel falls between the minimum calibrated travel and the maximum calibrated travel, the actual travel is calculated and stored.

7. The screw drive control method for a vehicle refrigerator drawer according to claim 6, characterized in that, If the absolute value of the difference between the first trip and the second trip is less than the trip difference threshold, the actual trip is calculated and stored.

8. The screw drive control method for a vehicle refrigerator drawer according to any one of claims 1-7, characterized in that, It also includes overvoltage protection, which includes the following steps: Real-time monitoring of the voltage of the brushless DC actuator; In response to the voltage being greater than a first voltage and the duration exceeding a first time threshold, the brushless DC actuator enters an overvoltage protection mode, the motor stops running and reports an overvoltage fault. In response to the voltage being less than the second voltage and the duration exceeding the second time threshold, the brushless DC actuator exits the overvoltage protection mode, the motor resumes operation, and the overvoltage fault is cleared.

9. The screw drive control method for a car refrigerator drawer according to any one of claims 1-7, characterized in that, It also includes undervoltage protection, which includes the following steps: Real-time monitoring of the voltage of the brushless DC actuator; In response to the voltage being less than the third voltage and the duration exceeding the third time threshold, the brushless DC actuator enters the undervoltage protection mode, the motor stops running and reports an undervoltage fault. In response to the voltage being greater than the fourth voltage and the duration exceeding the fourth time threshold, the brushless DC actuator exits the undervoltage protection mode, the motor resumes operation, and the undervoltage fault is cleared.

10. The screw drive control method for a vehicle refrigerator drawer according to any one of claims 1-7, characterized in that, It also includes hardware overvoltage protection, which includes the following steps: Real-time monitoring of the voltage of the brushless DC actuator; If the voltage is greater than the fifth voltage, the motor will stop running.

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