Automatic door position detection method based on current and hall position variance

Abstract

The application discloses an automatic door limit position detection method based on current and Hall position variance, and relates to the field of automatic door limit position detection methods.The limit position detection method is applied to an automatic door control system adopting a permanent magnet synchronous motor and a Hall sensor, and comprises the following steps: in a low-speed self-checking operation, a q-axis current filter value of the motor and Hall position information are acquired in real time; when it is detected that the q-axis current filter value continuously exceeds a first current threshold value for a first preset time length and the cumulative value thereof exceeds a corresponding product, a primary limit position flag is triggered; subsequently, the Hall position information is analyzed, the variance of a Hall code value is calculated, and if the variance is smaller than a preset threshold value, it is determined that a limit position point is reached.The application also relates to door closing maintenance control after the limit position point is reached and a corresponding controller.The application improves the accuracy and anti-interference ability of limit position detection through double judgment of current and position variance, and avoids the risk of motor blockage and door body overspeed impact.

Description

Technical Field

[0001] This invention relates to an automatic gate limit detection method based on the variance of current and Hall position, and pertains to the field of automatic gate limit detection methods. Background Technology

[0002] In automatic door control systems, permanent magnet synchronous motors are typically used to drive the door movement. To control this motor, field-oriented control technology is commonly employed, which requires real-time, precise rotor position information. For cost reasons, Hall effect position sensors are widely used due to their high stability and ability to obtain rotor position in real time, but their resolution is relatively low (only six Hall code values ​​change per electrical rotation of the motor).

[0003] Automatic door controllers need to be compatible with doors of varying lengths; therefore, the controller must have the ability to adaptively detect the positions of the mechanical limit points for opening and closing. The distance between these two limit points is the travel distance of the automatic door, which is the fundamental guarantee for subsequent path planning (such as acceleration, constant speed, and deceleration) during door operation, and is crucial for achieving smooth and safe door opening and closing actions.

[0004] In existing technologies, detecting door opening and closing limit points often results in inaccurate detection due to imperfect algorithms, continuous motor stalling and overcurrent, or high current squeezing the door body. This can not only damage the motor but also pose a safety hazard as the motor may overspeed after the door is fully closed, potentially causing it to collide with people or objects.

[0005] To address this, an automatic gate limit detection method based on the variance of current and Hall position is proposed. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the purpose of this invention is to provide an automatic gate limit detection method based on the variance of current and Hall position.

[0007] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0008] An automatic door limit detection method based on current and Hall position variance includes: Step S1, real-time monitoring: During the low-speed operation of the automatic door in the opening and closing limit self-test, the q-axis current filter value of the motor is acquired in real time. and rotor position information provided by Hall effect position sensors;

[0009] Step S2, Primary Limit Judgment: When the q-axis current filter value is detected to continuously exceed the first current threshold... The first preset time period is reached, and its cumulative value When the current exceeds the product of the first current threshold and the number of samples (N1) within the first preset time period, the primary limit flag is triggered;

[0010] Step S3, Secondary stall condition analysis: After the primary limit flag is triggered, the rotor position information is analyzed;

[0011] If the rotor position information meets the preset stopping condition within the second preset time period, it is determined that the automatic door has reached the mechanical limit point.

[0012] The stagnation condition includes at least one of the following two determination methods:

[0013] Method A: During the second preset time period, the Hall code value output by the Hall position sensor remains unchanged;

[0014] Method B: Within the second preset time period, calculate the variance of the Hall code value. When the variance value is less than a preset variance threshold... When the time condition is met, it is determined that the stagnation condition is satisfied.

[0015] Furthermore, the variance in method B is calculated using a moving average method, specifically including:

[0016] S31, Define an array of length n. Used to store continuous Hall position data and define an index. Points to the location of the latest data;

[0017] S32, when new Hall position data When it arrives, update the array: subtract the oldest data from the array sum. And add new data, while updating the data and Compared with the average ;

[0018] S33, based on the updated array, calculate the average value of each data point in the array relative to the current average. The sum of squared deviations gives the variance value at the current time. .

[0019] Further, in step S1, the q-axis current filter value By analyzing the q-axis current sampled in real time The result is obtained by performing a first-order RC low-pass filter.

[0020] The calculation formula for the first-order RC low-pass filter is as follows:

[0021] ;

[0022] In the formula: For the first Second Filtered output results; For the first Second Filtered output results. For the first Second The true value, where a is the filter coefficient (0 <a<1)。

[0023] Further, in step S2, the accumulated value The calculation formula is:

[0024] ;

[0025] Where N1 is the total number of samplings within the first preset time period.

[0026] Furthermore,

[0027] Step M1, set the speed limit value ;

[0028] Step M2: After the door closing action is completed, the actual speed of the motor is detected in real time;

[0029] Step M3: Compare the absolute value of the actual rotational speed with the speed limit value, and dynamically switch the control mode based on the comparison result;

[0030] When the absolute value of the actual rotational speed is less than or equal to the speed limit value, a pure current loop control mode is adopted, wherein the q-axis current setpoint of the current loop is a constant sustaining current setpoint. ;

[0031] When the absolute value of the actual rotational speed is greater than the speed limit value, the system switches to a dual closed-loop control mode with both speed and current loops, where the setpoint of the speed loop is zero to limit motor overspeed.

[0032] Furthermore, the sustaining current setting value The configuration is based on the weight of the automatic door.

[0033] Furthermore, the switching of the control mode is smooth, continuously monitoring the actual motor speed during operation and adjusting the speed based on its relationship with the speed limit value. The system dynamically switches between pure current loop control mode and speed-current dual closed-loop control mode based on the real-time comparison results.

[0034] The beneficial effects of this invention are:

[0035] By using the dual conditions of "increased current" and "Hall position stagnation" for limit judgment, compared with the solution that relies solely on current, the probability of false triggering caused by interference or instantaneous resistance is greatly reduced, ensuring that the gate can operate accurately in place, thereby improving its applicability.

[0036] During the limit detection phase, the algorithm promptly identifies stalled motors, preventing them from burning out due to prolonged high-current stall and ensuring motor safety. During the door closing phase, the dual control mode ensures sufficient holding force after closing while actively suppressing motor overspeed caused by external thrust, fundamentally avoiding the risk of high-speed door impact and effectively protecting the door from damage.

[0037] This method determines the position by analyzing the current and position signals of the motor during operation. It does not rely on specific types of sensors or complex mechanical structures, thus making it applicable to doors of different lengths and weights and improving its applicability. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0039] Figure 1 This is a schematic diagram of the overall structure of the automatic door system (including controller, motor, and Hall sensor) of the present invention.

[0040] Figure 2 This is an overall flowchart of the automatic gate limit detection method based on the variance of current and Hall position in an embodiment of the present invention.

[0041] Figure 3 This is a schematic diagram of the logic for determining the cumulative value of the filtered q-axis current in an embodiment of the present invention.

[0042] Figure 4 This is a schematic diagram illustrating the logic of determining the pause time based on the Hall code value in an embodiment of the present invention.

[0043] Figure 5 This is a schematic diagram illustrating the principle of Hall position variance calculation and judgment in this embodiment of the invention, focusing on the moving average array. The update mechanism.

[0044] Figure 6 This is a detailed execution flowchart of the third judgment condition (variance calculation and judgment) in an embodiment of the present invention.

[0045] Figure 7 In this embodiment of the invention, the first-order RC low-pass filter affects the q-axis current. A schematic diagram of the filtering process.

[0046] Figure 8This is a flowchart illustrating the overall control logic of the automatic door closing maintenance control method in this embodiment of the invention.

[0047] Figure 9 In this embodiment of the invention, during the door closing maintenance phase, the actual motor speed and speed limit value are used as the basis. A diagram illustrating the dynamic switching between pure current loop control mode and speed-current dual closed-loop control mode.

[0048] Figure 10 This is a hardware architecture block diagram of the automatic door controller in an embodiment of the present invention.

[0049] Figure 11 In this embodiment of the invention, under low-speed self-test mode, the motor speed and q-axis current are... Filtering current A schematic diagram of the waveform showing the change of Hall position over time.

[0050] Figure 12 In this embodiment of the invention, during the door closing maintenance phase, when the door is subjected to external thrust, the actual motor speed, control mode switching, and maintenance current are adjusted. The response waveform diagram. Detailed Implementation

[0051] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0052] Please see Figure 1-12 This invention provides a technical solution for an automatic gate limit detection method based on the variance of current and Hall position. In PMSM control, FOC control is often used to ensure maximum torque output throughout the entire control cycle. (Speed ​​reference) With rotor speed The difference is input to the speed loop PID controller, and the speed loop output is... As The shaft current loop is given when field weakening control is not performed. Axis current loop given =0, shaft current reference , With feedback current , The output after the difference is adjusted by PID control , Then, through inverse Park transform and SVPWM, the three-phase voltage is obtained. , , The motor is driven to rotate. The control system collects three-phase current. , , The feedback current is obtained after Clark transformation and Park transformation. , It participates in current loop control.

[0053] In FOC control, both the Park transform and the inverse Park transform require the rotor position. The closer the detected rotor position is to the true position, the closer the torque output during the control process will be to the maximum torque output.

[0054] Both rotor position and speed detection are obtained using Hall effect sensors. The three-phase Hall effect sensors are installed at 120° intervals.

[0055] During one electrical cycle of the motor, the high and low levels of each Hall output signal occupy 180° of electrical angle.

[0056] Therefore, for each electrical cycle of the motor, each Hall code value changes twice, and the three-phase Hall code values ​​change a total of six times, meaning a Hall state changes every 60 degrees. Thus, during control, it's necessary to record the actual rotor position corresponding to each Hall signal change point. For example, if the motor Hall code value changes in the sequence 6-2-3-1-5-4 (corresponding to forward rotation), when the Hall state changes to 2, the angle is 30°. When the motor rotates in reverse, the Hall code value changes in the sequence 4-5-1-3-2-6 (corresponding to reverse rotation), and when the Hall state changes to 2 in reverse rotation, the angle is 90°. This means that the corresponding angles are different when the same state change is detected in forward and reverse rotation. Therefore, it's necessary to determine the actual angle of the Hall signal based on the motor's rotation direction.

[0057] When the motor rotates, the motor Hall code value shows a change pattern of 4-5-1-3-2-6, which is consistent with the analysis above. Moreover, the Hall code value changes 6 times for every 360° rotation of the motor Hall angle.

[0058] The selected permanent magnet synchronous motor has a rated power of 120W, a drive voltage of 24V, and a rated current of 5A. Upon power-up of the automatic door controller, the permanent magnet synchronous motor begins to rotate in the forward direction, thus dragging the door body towards the opening direction. During the rotation, the motor speed is maintained at 600rpm, and the current is maintained at 0.3A, at which point the motor rotates at a constant speed.

[0059] During motor rotation, the speed is not constant. Although the actual set speed is 600 rpm, the uneven torque output and the non-strict 120° symmetry of the Hall effect sensor cause speed fluctuations. Simultaneously, since the motor is running under no-load, its current is low, fluctuating around 250mA. The motor's operating angle is obtained through speed interpolation.

[0060] When the door approaches the closing limit point, it begins to press against the limit point. At this time, the motor speed drops sharply. The speed loop PID controller, unable to reach the given speed reference, continues to increase the current loop output, causing the motor current to rise continuously until it reaches the current loop integral limit. For doors weighing less than 600 kg, to ensure the motor has sufficient resistance to overcome resistance during self-testing, the motor current loop PID integral limit and output limit are set to 5.5A. Without a corresponding limit detection algorithm, the motor will continue to press against the limit, maintaining a current of around 6A. At this point, the motor will exceed its rated current and stall, causing a sharp rise in motor temperature, potentially exceeding 100°C, posing a risk of motor burnout. Therefore, it is crucial to detect the limit promptly when the motor reaches it.

[0061] The motor extrusion process. Before the motor starts its self-check 47 seconds ago, the motor did not detect the limit switch and ran at a constant speed. At this time, the motor speed was 600 rpm, the motor current was maintained at about 0.3A, and the angle of the motor Hall interpolation was normal. At about 47 seconds, the motor reached the vicinity of the limit switch. Due to the presence of the limit switch, the motor could not move at a constant speed normally. At this time, the motor speed dropped sharply, dropping to about 0 rpm within 2 seconds, and the motor current rose to about 4A and was still rising sharply.

[0062] When performing limit detection, it is necessary to rely on the actual q-axis current of the motor in real time. But q-axis current Real-time participation in current loop control; however, to ensure the current loop bandwidth during motor operation, no filtering algorithm was added. The noise is relatively large; if the q-axis current is... Direct limit detection is prone to misjudgment, meaning the door may not have reached the corresponding opening limit, but the algorithm interprets it as having reached the limit, resulting in incomplete door opening. Therefore, a first-order RC low-pass filter is used to detect the actual q-axis current. The basic formula for a first-order RC low-pass filter is as follows:

[0063] ;

[0064] In the formula: For the first Second Filtered output results; For the first Second Filtered output results. For the first Second The true value. Before and after the filter. and The comparison shows that filtering... Removed High-frequency noise and smoothness have been significantly improved.

[0065] The following is the method for triggering the limit switch. Since the current loop PID limit is set to 5.5A, when... achieve The above indicates that the motor current is exceeding the limit (for permanent magnet synchronous motors). (Set to 5.0A), at this time, the actual q-axis current is checked every 1ms. Accumulate data until a set time is reached. Then, the accumulated current is obtained. ,at this time .

[0066] ;

[0067] When the accumulated current When the current exceeds the limit within the set time range, record the Hall code value of the motor at this time as the motor's shut-off position.

[0068] The first method for detecting the limit switch only uses current to determine the limit, and sets the current value to a relatively large value. , Exceeding the motor's rated current It mainly serves as motor protection in extreme situations, when the current exceeds the rated current. Time reached When the motor stalls for approximately 0.5 seconds, the current remains around 5.5A, and the speed drops to around 0 rpm. The motor position also remains unchanged for an extended period. Between 0.5 and 7.5 seconds, the current consistently exceeds 5A. Therefore, at 7.5 seconds, the motor detects a limit switch and reduces the current. This method requires a relatively long period of motor stalling, resulting in significant heat generation and high power consumption. It should be used as a protection measure in extreme situations. During normal operation, a faster detection method should be used.

[0069] The second method for detecting limit switches uses a combination of motor current and Hall effect changes for judgment. When the motor stalls, one factor is the actual q-axis current. The q-axis current rises sharply, similar to the filtered current. The current also increases, but on the other hand, the motor stops rotating, and the motor Hall code value remains at a fixed value. At this point, the maximum detected current of the motor is... Set time ,at this time Meanwhile, during operation, the Hall effect timer is set to remain unchanged for a specified period. When the Hall state changes, Clear to 0, and when the Hall state remains unchanged. Keep timing, when hour The time during which the Hall effect remains unchanged reaches its maximum. If both conditions are met If the motor detects a limit switch, it is considered that the motor has successfully detected the limit switch.

[0070] Initially, the motor rotates normally. Around 4.6 seconds, it reaches the vicinity of the limit point and begins to compress it, causing the current to rise. The current reaches its maximum value of approximately 500mA around 5.3 seconds. During this process, because the limit point is not a purely rigid structure, the motor continues to move forward. The Hall code value can be observed to slowly change between 4.5 and 5.3 seconds. During this period, the Hall count remains relatively low, generally below 100, far less than the code setting. Therefore, the motor does not recognize that the limit has been reached and continues to press against the limit. Between 5.3 and 6.8 seconds later, it continues to press against the limit until the current exceeds... The cumulative time exceeded If the Hall code value remains unchanged for more than 1000ms, it is considered that the limit has been reached.

[0071] The third method for detecting the limit position uses a dual approach of measuring changes in motor current and position variance. When the motor reaches the limit position, the actual q-axis current of the motor decreases due to the reduction in motor speed. The q-axis current rises sharply, similar to the filtered current. The motor's position also fluctuates near the door's limit points due to varying door limit point structures. These limit points may have some elasticity, causing the motor to shake. In this case, both the first and second limit detection methods, because the Hall code values ​​are constantly changing, will not recognize the motor as having detected a limit, resulting in continuous shaking near the limit points. However, although the motor shakes, it remains within the limit points, and the average motor position after shaking remains essentially unchanged. Therefore, a variance calculation method can be used to calculate the motor variance in real time and detect the motor limit based on this variance. The principle of the variance calculation method is as follows: During automatic door operation, the motor's Hall position is stored in an array in real time. The array's iteration process uses a moving average method, which helps reduce the computational load of the algorithm and enables real-time data updates. The array is defined as follows: Its length is defined as That is, the maximum storage A sliding array of data, This is a coordinate index used to indicate the location of the latest data.

[0072]

[0073] upper part, The data stored in it is , The latest data is stored in , The earliest data is stored in .thereby, The sum of all data in the table is: The mean of the output is calculated at this time. When new data When it arrives, at this time First subtract The earliest data stored in The latest data Stored in At the same time Add 1, that is Reindex the latest data. The result is: When calculating the variance, each data point in the array is compared to the mean. The difference is calculated to obtain the deviation value, and the squared deviation values ​​are summed to obtain the final variance.

[0074] The variance value is compared with the preset maximum variance value. Make comparisons, such as If the Hall effect sensor position changes slowly over a period of time, it is assumed that there may be vibration at the limit position or that the motor is pressing against the limit. In this case, the motor is considered to have reached the closing limit position. This method can significantly reduce the vibration problem of automatic doors during operation and improve the stability of automatic door control.

[0075] Initially, the motor rotates normally. Around 3.8 seconds, it reaches the vicinity of the limit point and begins to compress, causing the current to rise. When the current exceeds 4A, variance calculation begins. Around 4.2 seconds later, the variance is calculated. Because the limit point is not a completely rigid structure, the motor's Hall effect sensor continues to change, and the motor position continues to increase. However, as the compressive force increases, the motor stops moving forward, remaining stationary or oscillating back and forth. At this point, the variance decreases significantly. The motor variance gradually decreases until it falls below the maximum variance value. When the motor is in position, it is considered to be in position. It can be seen that the time from when the motor starts to compress the limit at 3.8s to when the limit is detected at 4.8s is only 1s, which greatly reduces the limit detection time.

[0076] To prevent automatic doors from not closing properly after closing due to asymmetrical installation, which could cause gaps between the two door panels and lead to door vibration, a holding force needs to be added to ensure that the two door panels remain tightly closed after the door is fully closed, thus preventing vibration. Therefore, a holding force along the q-axis is added after the automatic door closes, ensuring that the door panels remain tightly closed at the final position. Simply put, this involves providing the motor with a closing holding current. A current value causes a small adhesion force between the door panels, generally speaking. or In this control mode, the motor has a holding force, and the holding current is not too large, so the motor will not overheat.

[0077] The simple current control plus holding current described above presents a problem: since there is no speed limit, if a user pushes the door to the middle or the door stop is damaged, the motor may accelerate rapidly in the current-only control mode, potentially causing it to collide with a person, door frame, or wall at an uncontrolled speed, which could easily lead to harm. Therefore, after the door closes, a dual speed and current control mode is adopted. Unlike the traditional closed-loop control of speed and current, the dual speed and current control mode uses current control at low speeds and speed control at high speeds. The purpose is to maintain the closing torque while preventing the motor from overspeeding and damaging the door.

[0078] When the set speed limit is At this moment, it is about to As a speed limit after the door has closed, when the motor speed is... During this period, the motor speed did not exceed the set value. At this time, current loop control was used, and the current loop reference value could be determined by the set holding current. The decision, The current can be adjusted by matching the door weight to the controller, such as setting 1A for a light door and 2A for a heavy door. During current limiting, the motor speed still needs to be monitored in real time. When motor overspeed is detected, the actual speed will be less than [the specified value]. Or the actual speed is greater than At this point, the control mode changes from simple current loop control to dual closed-loop control (speed loop and current loop) to limit motor overspeed. Similarly, in the dual closed-loop control mode, the motor speed is monitored in real time, and when the motor speed returns to normal... In between, it switches back to pure current loop control. Through this dual speed and current control mode, it achieves a smooth transition between the pure current loop and the dual speed and current closed-loop control mode according to the motor speed. This not only ensures the maintenance current after the door is closed, but also avoids the damage caused by motor overspeed, greatly improving the stability of the automatic door during the control process.

[0079] Although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. An automatic gate limit detection method based on current and Hall position variance, characterized in that, An automatic door control system employing a permanent magnet synchronous motor and a Hall position sensor, the method comprising: Step S1, Real-time monitoring: During the low-speed operation of the automatic door during the opening and closing limit self-check, the q-axis current filter value of the motor is acquired in real time. and rotor position information provided by Hall effect position sensors; Step S2, Primary Limit Judgment: When the q-axis current filter value is detected to continuously exceed the first current threshold... The first preset time period is reached, and its cumulative value When the current exceeds the product of the first current threshold and the number of samples (N1) within the first preset time period, the primary limit flag is triggered; Step S3, Secondary stall condition analysis: After the primary limit flag is triggered, the rotor position information is analyzed; If the rotor position information meets the preset stopping condition within the second preset time period, it is determined that the automatic door has reached the mechanical limit point. Step S4: "If it is determined that the mechanical limit point has been reached, control the motor to stop running or reverse to release the pressure; The stagnation condition includes at least one of the following two determination methods: Method A: During the second preset time period, the Hall code value output by the Hall position sensor remains unchanged; Method B: Within the second preset time period, calculate the variance of the Hall code value. When the variance value is less than a preset variance threshold... When the time condition is met, it is determined that the stagnation condition is satisfied.

2. The automatic gate limit detection method based on current and Hall position variance according to claim 1, characterized in that, The variance calculation in method B uses the moving average method, specifically including: S31, Define an array of length n. Used to store continuous Hall position data, and an index is defined to point to the position of the latest data; S32, when new Hall position data When it arrives, update the array: subtract the oldest data from the array sum. And add new data, while updating the data and Compared with the average ; S33, based on the updated array, calculate the average value of each data point in the array relative to the current average. The sum of squared deviations gives the variance value at the current time. .

3. The automatic gate limit detection method based on current and Hall position variance according to claim 1, characterized in that, In step S1, the q-axis current filter value By analyzing the q-axis current sampled in real time The result is obtained by performing a first-order RC low-pass filter. The calculation formula for the first-order RC low-pass filter is as follows: ； In the formula: For the first Second Filtered output results; For the nth time Filtered output results For the nth time The true value, where a is the filter coefficient (0 <a<1)。 4. The automatic gate limit detection method based on current and Hall position variance according to claim 1, characterized in that, In step S2, the accumulated value The calculation formula is: ； Where N1 is the total number of samplings within the first preset time period.

5. An automatic door closing maintenance control method, characterized in that, The control stage of the automatic gate limit detection method based on the current and Hall position variance as described in claim 1 includes: Step M1, set the speed limit value ; Step M2: After the door closing action is completed, the actual speed of the motor is detected in real time; Step M3: Compare the absolute value of the actual rotational speed with the speed limit value, and dynamically switch the control mode based on the comparison result. When the absolute value of the actual rotational speed is less than or equal to the speed limit value, a pure current loop control mode is adopted, wherein the q-axis current setpoint of the current loop is a constant sustaining current setpoint. ; When the absolute value of the actual rotational speed is greater than the speed limit value, the system switches to a dual closed-loop control mode with both speed and current loops, where the setpoint of the speed loop is zero to limit motor overspeed.

6. The automatic door closing maintenance control method according to claim 5, characterized in that, The sustaining current setting value The configuration is based on the weight of the automatic door.

7. The automatic door closing maintenance control method according to claim 5, characterized in that, The switching of the control mode is smooth, and the actual speed of the motor is continuously monitored during operation, and the speed is adjusted according to its relationship with the speed limit value. The system dynamically switches between pure current loop control mode and speed-current dual closed-loop control mode based on the real-time comparison results.

8. An automatic door controller, characterized in that, The device includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the automatic door limit detection method based on current and Hall position variance as described in any one of claims 1 to 4, and / or implements the automatic door closing maintenance control method as described in any one of claims 5 to 7.

9. An automatic door system, characterized in that, include: The door body, the permanent magnet synchronous motor that drives the door body, the Hall position sensor for detecting the position of the motor rotor, and the automatic door controller as described in claim 8.

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