Control method and system for an electric tailgate

Abstract

The application relates to a control method and system for an electric tailgate, the control method comprising: during movement of the electric tailgate from a self-starting position to a critical position, controlling the movement speed of the electric tailgate by adopting a proportional integral adjustment combined with feedforward control, wherein the critical position is a position of the electric tailgate when a remaining opening angle difference exists in completing current movement; during movement of the electric tailgate for the remaining opening angle difference, controlling the movement speed of the electric tailgate by adopting a mode that the voltage decreases with time. The application introduces feedforward control on the basis of PI adjustment to control the movement speed of the electric tailgate 100, so that the electric tailgate 100 runs stably and responds quickly, and can be quickly started even when the resistance is large.

Description

Technical Field

[0001] This application relates to the field of vehicles, and more specifically, to a control method and system for an electric tailgate. Background Technology

[0002] The tailgate, located at the rear of a vehicle, forms the trunk and is a crucial component. It comprises numerous parts and has a complex structure. To facilitate opening and closing, some vehicles feature a power tailgate. Opening a power tailgate typically involves pressing a button on the remote key or inside the vehicle, and it opens automatically. Similarly, closing it involves pressing the close button on the remote key or inside the vehicle. Powered tailgates are usually driven by a DC motor. During opening and closing, the resistance experienced by a DC motor-driven power tailgate varies. Therefore, to ensure smooth operation, the drive motor needs to be controlled. Summary of the Invention

[0003] Embodiments of this application provide a control method and system for an electric tailgate, which enables the electric tailgate 100 to operate smoothly and respond quickly, and to start quickly even when there is high resistance.

[0004] According to one aspect of this application, a control method for an electric tailgate is provided, characterized in that the control method includes: during the process of the electric tailgate moving from a starting position to a critical position, using proportional-integral regulation combined with feedforward control to control the movement speed of the electric tailgate, wherein the critical position is the position where the electric tailgate has a remaining opening angle difference from completing the current movement; and during the process of the electric tailgate moving with the remaining opening angle difference, using a voltage decreasing over time to control the movement speed of the electric tailgate.

[0005] In some embodiments of the first aspect of this application, optionally, the control method further includes calibrating a target angular velocity corresponding to a plurality of different tailgate opening angles; and controlling the movement speed of the electric tailgate includes: controlling the angular velocity of the electric tailgate based on the calibrated target angular velocities corresponding to the plurality of different tailgate opening angles.

[0006] In some embodiments of the first aspect of this application, optionally, the method of using proportional-integral regulation combined with feedforward control to control the movement speed of the electric tailgate includes: using a proportional-integral output voltage combined with a feedforward voltage as a control output voltage to control the movement speed of the electric tailgate, wherein the feedforward voltage is a calibrated value that does not change with angle and operating conditions.

[0007] In some embodiments of the first aspect of this application, optionally, controlling the movement speed of the electric tailgate by decreasing voltage over time includes controlling the movement speed of the electric tailgate by decreasing voltage uniformly over time.

[0008] In some embodiments of the first aspect of this application, optionally, the remaining opening angle difference is less than or equal to 10°.

[0009] In some embodiments of the first aspect of this application, optionally, the proportional-integral adjustment uses different proportional-integral coefficients under different operating conditions.

[0010] In some embodiments of the first aspect of this application, the control method may optionally further include: when the start time of the electric tailgate reaches a critical start time, acquiring the motion angle of the electric tailgate; and determining whether the electric tailgate encounters an obstacle based on whether the motion angle of the electric tailgate at the critical start time is less than a critical motion angle.

[0011] In some embodiments of the first aspect of this application, the control method may optionally further include: determining whether the electric tailgate encounters an obstacle based on the motor current used for the electric tailgate.

[0012] In some embodiments of the first aspect of this application, optionally, if it is determined that the electric tailgate encounters an obstacle, the electric tailgate is controlled to perform a reverse movement.

[0013] In some embodiments of the first aspect of this application, optionally, determining whether the electric tailgate encounters an obstacle based on the motor current used for the electric tailgate includes: acquiring the movement angle of the electric tailgate; acquiring the motor current used for the electric tailgate; if the movement angle is less than or equal to the critical movement angle, determining whether the electric tailgate encounters an obstacle based on whether the peak value of the currently acquired motor current is greater than the critical current; and if the movement angle is greater than the critical movement angle, determining whether the electric tailgate encounters an obstacle based on whether the current increment ∆I of the currently acquired motor current is greater than the critical current increment.

[0014] In some embodiments of the first aspect of this application, optionally, the critical motion angle is calibrated based on a first motion angle A that the electric tailgate moves from startup to when the motor current reaches stability under different operating conditions, and a second motion angle B that the electric tailgate moves from when it encounters an obstacle to when the force of the obstacle reaches the critical anti-pinch force under different operating conditions.

[0015] In some embodiments of the first aspect of this application, optionally, the critical start time is calibrated based on the time required for the electric tailgate to move to the sum of the first movement angle A and the second movement angle B under different operating conditions.

[0016] In some embodiments of the first aspect of this application, optionally, the current increment of the motor current is obtained by: subtracting the second motion angle B from the current opening angle position of the electric tailgate to obtain the previous opening angle position; and obtaining the current motor current I of the electric tailgate corresponding to the current opening angle position. 当前 And the previous motor current I corresponding to the previous opening angle position. 先前 ; and the current motor current I 当前 Subtract the previous motor current I 先前 .

[0017] According to a second aspect of this application, a control system for an electric tailgate is provided, the control system comprising: a memory configured to store instructions; and a processor configured to execute the instructions such that the control system performs a control method as described in any one of the first aspects of this application.

[0018] According to a third aspect of this application, a computer-readable storage medium is provided, wherein instructions are stored therein, which, when executed by a processor, cause the processor to perform the control method as described in any one of the first aspects of this application.

[0019] According to a fourth aspect of this application, a vehicle is provided, the vehicle including a power tailgate and a control system for the power tailgate. The control system is the control system described in the second aspect of this application.

[0020] The method and system for electric tailgates adopted in this application can effectively ensure the smooth operation of the electric tailgate. Some embodiments of this application use the tailgate angular velocity to calibrate the electric tailgate speed, making the speed control of the electric tailgate more stable and effective, and reducing the calibration workload. This application uses proportional-integral (PI) regulation combined with voltage feedforward to control the speed of the electric tailgate for most of its movement time, resulting in smooth movement and faster response. During PI regulation, the control method of this application can use different PI coefficients according to the direction of movement of the electric tailgate and the sign of the speed error to ensure performance under various operating conditions. In addition, when the electric tailgate needs to be soft-stopped, a voltage decrease method is used to control the speed of the electric tailgate. This control method is simple and makes the speed of the electric tailgate more stable. For the control voltage used to drive the electric tailgate, some embodiments of this application use a filtered value as the control voltage to avoid fluctuations in the speed of the electric tailgate and the motor current.

[0021] During the smooth operation of the electric tailgate, some embodiments of this application can use the current increment within a calibrated angle to determine whether an obstacle has been encountered. Additionally, during startup, the amount of motion at the critical startup time can be used to determine whether an obstacle has been encountered, and under extreme conditions, the current peak value can be used to determine whether an obstacle has been encountered. This application can adopt appropriate obstacle detection and control strategies based on the characteristics of different operating conditions of the electric tailgate, thereby effectively ensuring the smooth operation of the electric tailgate. Attached Figure Description

[0022] The above and other objects and advantages of this application will become more fully clear from the following detailed description taken in conjunction with the accompanying drawings, wherein the same or similar elements are denoted by the same reference numerals.

[0023] Figure 1 A schematic diagram of the structure of an electric tailgate according to an embodiment of this application is shown; Figure 2A and 2B Simplified diagrams of the drive circuit for a motor of an electric tailgate according to one embodiment of this application are shown respectively; Figure 3 A schematic diagram of an electric tailgate speed control method according to an embodiment of this application is shown; Figure 4 A flowchart of an obstacle detection and control method for an electric tailgate according to a first embodiment of this application is shown; Figure 5 A flowchart of an obstacle detection and control method for an electric tailgate according to a second embodiment of this application is shown; Figure 6 A schematic diagram of a control system for an electric tailgate according to an embodiment of this application is shown. Detailed Implementation

[0024] For purposes of brevity and illustration, the principles of this application are described herein primarily with reference to exemplary embodiments thereof. However, those skilled in the art will readily recognize that the same principles are equivalently applicable to all types of control methods and systems for electric tailgates, and that these same or similar principles can be implemented therein, without departing from the true spirit and scope of this application.

[0025] Below, we will combine Figure 1 The structure of an electric tailgate 100 according to an embodiment of this application will be described below.

[0026] Figure 1 A schematic diagram of the structure of an electric tailgate 100 according to an embodiment of this application is shown. Figure 1As shown, the electric tailgate 100 is installed at the rear of the vehicle body 106 to form the vehicle's trunk together with the vehicle body 106. The electric tailgate 100 includes a tailgate panel 102 and a tailgate strut 104. One end of the tailgate strut 104 is mounted on the vehicle body 106, and the other end is connected to the tailgate panel 102, so that the tailgate strut 104 can support the tailgate panel 102 in the open and closed positions.

[0027] In some embodiments, the tailgate strut 104 may include a mechanical spring and a brake, which allows for easier opening and closing of the tailgate panel 102 and enables the tailgate panel 102 to be freely suspended in most positions. In some embodiments, the tailgate strut 104 may also include a strut motor 210 (see...). Figure 2A and Figure 2B The strut motor comprises planetary gears, a lead screw, a nut, and a ball joint. The strut motor drives the lead screw to rotate after being reduced in speed by two rows of planetary gears, thereby causing the lead screw to push the nut to move. The nut then moves the tailgate panel 102 via the ball joint. In some embodiments, the strut motor 210 may be equipped with a Hall sensor to sense the position of the tailgate panel 102 and the speed of the strut motor 210.

[0028] It should be noted that, for ease of understanding and description, this application may also directly describe the "position of the tailgate panel 102" as the "position of the electric tailgate 100," and the "opening and closing of the tailgate panel 102" as the "opening and closing of the electric tailgate 100." Furthermore, the embodiments described in this application utilize a "strut motor 210" to drive the electric tailgate 100; therefore, the "strut motor 210" may also be referred to as the "motor of the electric tailgate 100" or the "motor used to drive the electric tailgate 100."

[0029] Next, we will combine Figure 2A and 2B This application describes a drive circuit 200 for a motor of an electric tailgate 100 according to one embodiment of the present application.

[0030] Figure 2A and 2B Simplified diagrams of a drive circuit 200 for a motor of an electric tailgate 100 according to one embodiment of this application are shown. Figure 2A and 2B The drive circuit 200 for the motor of the electric tailgate 100 includes a strut motor 210 and four switches, wherein the strut motor 210 and the four switches are connected by wires to form an H-bridge circuit. In some embodiments, a voltage source (e.g., ...) can be connected to the top of the H-bridge circuit. Figure 2A and 2B(The 12V voltage shown) The bottom of the H-bridge circuit can be grounded. Using the above settings, the drive circuit 200 can adjust the speed of the strut motor 210 by inputting a high-frequency square wave voltage to the strut motor 210, thereby adjusting the speed of the strut motor 210 by changing the duty cycle of the square wave voltage, wherein the effective value of the motor voltage is equal to the power supply voltage multiplied by the duty cycle.

[0031] This application configures the drive circuit 200 as an H-bridge circuit, thereby controlling the forward and reverse rotation of the strut motor 210 by switching four switches on and off. Figure 2A and 2B The four switches are referred to as the upper left switch 202, the upper right switch 204, the lower left switch 206, and the lower right switch 208, respectively. In some embodiments, the four switches may be in the form of four MOSFETs, and the on / off state of the four MOSFETs may be controlled by a microcontroller unit (MCU).

[0032] Figure 2A The driving state of the driving circuit 200 is shown. For example... Figure 2A As shown, when the upper left switch 202 and the lower right switch 208 are closed, and the upper right switch 204 and the lower left switch 206 are open, current can flow from the positive terminal of the power supply through the strut motor 210 to the negative terminal. At this time, the strut motor 210 is driven, and the drive circuit 200 is in a driven state. In some embodiments, Figure 2A The driving state of the driving circuit 200 shown can correspond to the forward rotation state of the strut motor 210.

[0033] Figure 2B The freewheeling state of the drive circuit 200 is shown. For example... Figure 2B As shown, with the lower left switch 206 and lower right switch 208 closed, and the upper left switch 202 and upper right switch 204 open, the two ends of the strut motor 210 are short-circuited, and the drive circuit 200 is in freewheeling mode. When the drive circuit 200 switches from driving mode to freewheeling mode, due to the self-inductance of the motor coil in the strut motor 210, the motor current does not decrease rapidly, but decreases slowly through the freewheeling circuit. If the motor current does not drop to 0 during the freewheeling process, the strut motor 210 will always have driving force. If the electric tailgate 100 is still moving when the motor current drops to 0, the motional electromotive force in the strut motor 210 will generate a reverse current, which will hinder the movement of the electric tailgate 100, thus producing a braking effect on the electric tailgate 100. This also shows that lowering the duty cycle or directly reducing the duty cycle to 0 will have a braking effect on the electric tailgate 100.

[0034] In some embodiments, Figure 2AThe driving state of the drive circuit 200 shown corresponds to the forward rotation state of the strut motor 210, which can correspond to the action of opening the electric tailgate 100. That is, when the electric tailgate 100 needs to be opened, this can be achieved by controlling the upper left switch 202 and lower right switch 208 of the H-bridge circuit to be closed, and the upper right switch 204 and lower left switch 206 to be open, thereby causing the strut motor 210 to rotate forward. In some embodiments, if the electric tailgate 100 needs to be closed, this can be achieved by controlling the upper right switch 204 and lower left switch 206 of the H-bridge circuit to be closed, and the upper left switch 202 and lower right switch 208 to be open, thereby causing the strut motor 210 to rotate in reverse. Therefore, the forward rotation state of the strut motor 210 enables the electric tailgate 100 to perform the opening task, and the reverse rotation state of the strut motor 210 enables the electric tailgate 100 to perform the closing task.

[0035] Next, combined Figures 3 to 5 This application describes a control method for an electric tailgate 100 according to one embodiment.

[0036] Using a fixed voltage to control the opening and closing of the electric tailgate 100, or changing the voltage according to the position of the electric tailgate 100, cannot guarantee the smooth operation of the electric tailgate 100 under different operating conditions. To effectively ensure the smooth operation of the electric tailgate 100, this application employs closed-loop control, controlling the speed of the electric tailgate 100 by feeding the output back to the input to influence the input. In some embodiments, smooth movement of the electric tailgate 100 can be achieved through proportional-integral (PI) regulation. To make the electric tailgate 100 respond more quickly, even under high resistance, this application introduces feedforward control on top of PI regulation, thus enabling the use of a combination of PI regulation and feedforward control to control the movement speed of the electric tailgate 100.

[0037] Figure 3 A schematic diagram illustrating the use of PI control combined with feedforward control to control the speed of the electric tailgate 100 according to an embodiment of this application is shown. Figure 3 As shown, in some embodiments, based on the Hall sensor mounted on the strut motor 210, the position of the electric tailgate 100's angle 304 (i.e., the opening angle of the tailgate panel 102) can be sensed according to the count of Hall pulses 302, and the angular velocity 306 of the electric tailgate 100 can be sensed according to the frequency of the Hall pulses 302. The angle 304 (opening angle) of the electric tailgate 100 described herein represents the angle of movement of the electric tailgate 100 from its closed position. Under smooth operation of the electric tailgate 100, the angular velocity corresponding to the opening angle position of the electric tailgate 100 should be approximately constant for most of its movement.

[0038] To more effectively and accurately reflect the movement speed of the power tailgate 100 in a simple manner, in some embodiments, angular velocity can be used to calibrate the movement speed of the power tailgate 100, rather than the linear velocity of the tailgate strut 104 extension or the motor speed. Optionally, the control method for the power tailgate 100 further includes calibrating a corresponding target angular velocity for multiple different tailgate opening angles of the power tailgate 100, so that the calibrated target angular velocity 308 can be found based on the angle 304 of the power tailgate 100 obtained in the aforementioned steps. The calibration method using the target angular velocity 308 relative to the opening angle can efficiently and accurately describe the state of the power tailgate 100 during smooth movement, thereby helping the control method for the power tailgate 100 to effectively control the movement speed of the power tailgate 100 and ensure the smooth operation of the power tailgate 100.

[0039] The applicant discovered that, for the same vehicle and under similar operating conditions (e.g., when the power tailgate 100 is opened or closed, or when the vehicle is in an uphill or downhill position), the target angular velocity 308 relative to the tailgate opening angle is determined when the power tailgate 100 is moving smoothly. In other words, the applicant discovered that, for the same vehicle and under similar operating conditions, the target angular velocity 308 can also be determined when the power tailgate 100 is at a determined opening angle position during smooth operation. Therefore, some embodiments can be calibrated using multiple different opening angles of the target angular velocity 308 relative to the power tailgate 100, thereby allowing control of the angular velocity of the power tailgate 100 based on the calibrated target angular velocity 308 corresponding to multiple different tailgate opening angles. For example, for the 80° opening angle that the electric tailgate 100 can move, a specific target angular velocity 308 can be calibrated corresponding to opening angle positions of 10°, 20°, 30°, 40°, 50°, 60° and 70° respectively.

[0040] When calibrating using the target angular velocity relative to the tailgate opening angle, the target angular velocity relative to the tailgate opening angle gradually increases because the electric tailgate 100 accelerates during startup. In some embodiments, to further ensure the smoothness of the electric tailgate 100 startup and meet the requirements of the tailgate angular velocity at different angles, the change in the target angular velocity relative to the tailgate opening angle can also be used for calibration during the startup of the electric tailgate 100, and the absolute value of the target angular velocity relative to the tailgate opening angle can be used for calibration after the startup process is completed.

[0041] Compared to using the target angular velocity 308 relative to the opening angle position of the power tailgate 100 for calibration, using the target angular velocity 308 relative to the start time of the power tailgate 100 (i.e., the time from start to finish) for calibration makes it impossible to control the power tailgate 100 to achieve stable and reliable movement. This is because the target angular velocity 308 calibrated relative to the start time of the power tailgate 100 cannot accurately describe the state of the power tailgate 100 during smooth movement. For example, if a tailgate sealing strip is provided at the edge of the tailgate panel 102 of the power tailgate 100, due to the large resistance of the tailgate sealing strip and air resistance, the power tailgate 100 may need to be accelerated when it is close to locking. In addition, if the power tailgate 100 starts closing at different positions, the locking time of the power tailgate 100 will be different. That is to say, even corresponding to the same start time, the power tailgate 100 may have different target angular velocities, so it is not advisable to use angular velocity relative to time for calibration. The embodiments of this application correspond the opening angle position (e.g., angle 304) of the electric tailgate 100 to the target angular velocity 308 by calibration, which can ensure that the electric tailgate 100 has a stable speed at each opening angle position during the movement.

[0042] In some embodiments, after calibrating the target angular velocity 308 relative to different opening angle positions of the electric tailgate 100, the target angular velocity 308 corresponding to the current angle 304 of the electric tailgate 100 (e.g., obtained by counting Hall pulses 302) can be determined through calibration. On the other hand, the current angular velocity 306 of the electric tailgate 100 can be sensed based on the frequency of the Hall pulses 302. The control error 310 of the current control method can be obtained based on the difference between the current angular velocity 306 and the target angular velocity 308. Based on the control error 310 obtained by subtraction, a feedback value 312 can be obtained by PI calculation. Subsequently, in some embodiments, the control method of this application can add the feedback value 312 obtained by PI calculation to the feedforward value 314 to obtain a theoretical output 316. In some embodiments, the theoretical output 316 can be a control output voltage, the feedback value 312 can be a PI output voltage, and the feedforward value 314 can be a feedforward voltage. In other words, the movement speed of the electric tailgate 100 can be controlled by using the PI output voltage combined with the feedforward voltage as the control output voltage. Introducing feedforward regulation so that the PI output voltage plus the feedforward voltage as the control output allows the PI regulation to respond more quickly. Considering that under most operating conditions, a constant voltage is sufficient for the electric tailgate 100 to operate at a relatively smooth speed and it is difficult to perceive the current operating condition, some embodiments of this application can set the feedforward voltage to a calibrated value that does not change with angle and operating conditions.

[0043] In some embodiments, to help stabilize the motor current, preventing large fluctuations and short-term peaks, and to avoid shaking of the electric tailgate 100 during startup, and to reduce the impact of Hall sensor measurement errors on the PI control output, the theoretical output 316 can be filtered after obtaining it to obtain the actual output 318. For example, if the theoretical output 316 corresponds to the control output voltage, the control output voltage can be filtered. In some embodiments, the theoretically calculated value of the theoretical output 316 for the current cycle can be filtered based on the following formula to obtain the actual output of the actual output 318 for the current cycle: Current cycle actual output = current cycle theoretical calculation value × voltage filter coefficient + previous cycle actual output × (1 - voltage filter coefficient); The voltage filter coefficient can be calibrated, and by reducing the voltage filter coefficient, the actual output 318 can change more smoothly, reducing tailgate vibration.

[0044] In some embodiments, to improve the performance of PI control, different PI coefficients can be used under different scenarios according to system characteristics, so as to make the operation of the electric tailgate 100 smoother. Optionally, since the force on the electric tailgate 100 is different under different slopes, the drive load of the strut motor 210 will vary greatly. It is difficult to make the electric tailgate 100 open and close smoothly using a single set of PI coefficients. Therefore, the PI coefficients for opening and closing can be calibrated separately. Optionally, different PI coefficients can also be used according to the sign of the error between the actual angular velocity 306 and the target angular velocity 308 of the electric tailgate 100. When the actual angular velocity 306 of the electric tailgate 100 is less than the target angular velocity 308, the PI coefficient should not be too large, because an excessively large PI coefficient is prone to overshoot, which will cause the electric tailgate 100 to vibrate. When the actual angular velocity 306 of the electric tailgate 100 is greater than the target angular velocity 308, a larger PI coefficient should be used, because a slight reduction in the duty cycle will not produce a significant braking effect. The braking effect is only significant when the duty cycle is close to 0. In some embodiments, considering both the opening and closing of the electric tailgate 100 and the positive or negative value of the error between the actual angular velocity 306 and the target angular velocity 308, four sets of PI coefficients can be used. In other embodiments, to suit the characteristics of different disclosures, multiple different sets of PI coefficients can be used.

[0045] During the movement of the electric tailgate 100, when the user stops the electric tailgate 100 or when the electric tailgate 100 reaches its maximum opening angle and stops, the electric tailgate 100 needs to decelerate slowly and gradually come to a stop; that is, the electric tailgate 100 needs to achieve a soft stop. However, during the soft stop of the electric tailgate 100, due to the poor linearity of the motor braking control in the H-bridge circuit, and the significant difference in characteristics between the system controlling motor braking and the system controlling motor acceleration, it is difficult to ensure that the speed is not jittered when using PI regulation. In other words, it is difficult to use PI regulation to control the electric tailgate 100 during the soft stop. In some embodiments, in order to ensure the smooth operation of the electric tailgate 100 during the soft stop, a soft stop method in which the voltage decreases over time can be used to control the movement speed of the electric tailgate 100. This method is simple to control and the control error is difficult for the human eye to perceive. For example, the electric tailgate 100 can be controlled by using a method in which the voltage decreases uniformly over time.

[0046] Based on the above description, in order to better control the smooth operation of the electric tailgate 100, the movement process of the electric tailgate 100 during the opening or closing task can be divided into two stages: i) the stage from the start of the electric tailgate 100 to the completion of most of the angle of movement; and ii) the soft stop stage of the electric tailgate 100. Stage i) can be described as the movement process from the start position to the critical position, where the critical position can be the position where the electric tailgate 100 has a remaining opening angle difference from completing the current opening or closing movement. Stage ii) can be described as the movement process where the electric tailgate 100 completes the movement of the remaining opening angle difference. The "start position" mentioned in this application refers to the position where the speed of the electric tailgate 100 is zero just before the opening movement. That is, the electric tailgate 100 begins to perform the movement task immediately after the "start position".

[0047] In some embodiments, the remaining opening angle difference can be any degree value less than or equal to 10°. Optionally, if the opening angle of the power tailgate 100 when fully open is 80° and the remaining opening angle difference is 2°, then the critical position is the position where the power tailgate 100 has performed an opening or closing task with a movement angle of 78°. In this embodiment, for the case where the power tailgate 100 performs an opening task, stage i) is the power tailgate 100 moving from the fully closed position to the 78° opening angle position, and stage ii) is the power tailgate 100 moving from the 78° opening angle position to the fully open 80° opening angle position; for the case where the power tailgate 100 performs a closing task, stage i) is the power tailgate 100 moving from the fully open 80° opening angle position to the 2° opening angle position, and stage ii) is the power tailgate 100 moving from the 2° opening angle position to the fully closed position.

[0048] To ensure the smooth operation of the electric tailgate 100, different control methods can be used to control the movement speed of the electric tailgate 100 in some embodiments, taking into account the characteristics and requirements of the two movement stages of the electric tailgate 100: a) During the movement of the electric tailgate 100 from the starting position to the critical position, the movement speed of the electric tailgate 100 is controlled by PI regulation combined with feedforward control. b) During the movement of the electric tailgate 100 performing the remaining opening angle difference, the movement speed of the electric tailgate 100 is controlled by decreasing the voltage over time.

[0049] For example, in an embodiment where the electric tailgate 100 has an opening angle of 80° when fully open and a remaining opening angle difference of 2°, the movement speed of the electric tailgate 100 can be controlled by a combination of PI control and feedforward control during the process from the starting position to the point where the electric tailgate 100 has performed a 78° movement angle. During the movement of the electric tailgate 100 with the remaining 2° opening angle difference, the movement speed is controlled by a voltage decreasing over time. This control method, tailored to the movement characteristics of the electric tailgate 100, divides the movement process into two stages and applies matching control schemes to each stage, thereby effectively ensuring the smooth operation of the electric tailgate 100 throughout the entire movement process.

[0050] To further ensure the smooth operation of the electric tailgate 100, prevent the electric tailgate 100 from pinching or hitting the user during operation, and prevent the electric tailgate 100 from stalling or damaging the motor and other parts due to encountering obstacles, in some embodiments, the control method of the electric tailgate 100 can also detect whether the electric tailgate 100 encounters an obstacle during operation. In some embodiments, when an obstacle is detected, the drive circuit 200 can be controlled to stop driving the electric tailgate 100, or the electric tailgate 100 can be further rotated in the opposite direction by a certain angle.

[0051] Below, we will combine Figure 4 and Figure 5 Methods 400 and 500 for obstacle detection and control of electric tailgate according to embodiments of this application are described below.

[0052] Figure 4 A flowchart of an obstacle detection and control method 400 for an electric tailgate according to a first embodiment of this application is shown. The detection and control method 400 determines whether the electric tailgate 100 has encountered an obstacle based on the amount of movement of the electric tailgate 100 at a critical start time. That is, based on the time from start to movement of the electric tailgate 100, the detection and control method 400 can obtain the movement angle at that moment and determine whether the movement angle reaches a critical movement angle to determine whether the electric tailgate 100 has encountered an obstacle. The term "start" as used herein refers to the state in which the electric tailgate 100 begins to perform an opening or closing task. Figure 4 As shown, the detection and control method 400 for determining whether the electric tailgate 100 has encountered an obstacle based on time includes steps S402 to S414.

[0053] In step S402, the detection control method 400 begins execution. In some embodiments, the detection control method 400 begins execution when the power tailgate 100 is activated. Once the detection control method 400 begins, step S404 is executed to start timing. It should be understood that the timing step performed in step S404 is equivalent to timing the activation time of the power tailgate 100. Step S406 is further executed after step S404.

[0054] In step S406, it is determined whether the accumulated start-up time in step S404 has reached the critical start-up time. If the accumulated start-up time of the electric tailgate 100 has not reached the critical start-up time, the process returns to step S406 to continuously determine whether the start-up time has reached the critical start-up time. In some embodiments, the critical start-up time can be determined as follows: Under various operating conditions, the movement angle performed by the electric tailgate 100 from self-start to when the current reaches stability is recorded by testing, and the maximum movement angle among multiple movement angles under various operating conditions is taken as the first movement angle A; Under various operating conditions, the movement angle performed by the electric tailgate 100 from encountering an obstacle to when the force of the obstacle equals the anti-pinch force is recorded by testing, and the maximum movement angle among multiple movement angles under various operating conditions is taken as the second movement angle B; The critical movement angle is calibrated based on the first movement angle A and the second movement angle B. Optionally, the critical movement angle is the sum of the first movement angle A and the second movement angle B; Under multiple operating conditions, the time required for the electric tailgate 100 to reach the critical movement angle from self-start is recorded by testing, and the critical start-up time is calibrated based on the maximum time value among multiple required times under multiple operating conditions. Optionally, the calibrated value of the critical start-up time can be obtained by adding a certain margin to the maximum time value. It should be noted that the first motion angle A and the second motion angle B are relatively small compared to the angles required for the electric tailgate 100 to fully perform the current opening or closing task, and the critical start time is also relatively short compared to the time required for the electric tailgate 100 to fully perform the current opening or closing task.

[0055] If the accumulated start time of the electric tailgate 100 reaches a critical start time, step S408 is executed. In step S408, the current movement angle of the electric tailgate 100 after the start time is obtained. Optionally, the movement angle of the electric tailgate 100 can be obtained by a Hall sensor installed on the strut motor 210. After step S408, step S410 is further executed.

[0056] In step S410, it is determined whether the movement angle performed by the electric tailgate 100 during the start-up time is less than a critical movement angle. As described above, the critical movement angle can be determined based on a first movement angle A and a second movement angle B. For example, the critical movement angle is the sum of the first movement angle A and the second movement angle B.

[0057] If the movement angle performed by the electric tailgate 100 is less than the critical movement angle, it can be determined that the electric tailgate 100 has encountered an obstacle. At this time, step S412 can be further executed to stop the currently executed movement task and perform a certain degree of reverse movement. For example, if an obstacle is detected during the opening of the electric tailgate 100, the current task of opening the electric tailgate 100 is stopped, and the electric tailgate 100 is controlled to move a small angle in the direction of closing the electric tailgate 100 to prevent the obstacle from damaging the electric tailgate 100.

[0058] If the movement angle performed by the electric tailgate 100 is greater than or equal to the critical movement angle, it can be determined that the electric tailgate 100 has not encountered an obstacle. In this case, step S414 can be further executed so that the electric tailgate 100 continues to perform subsequent movements consistent with the previous movement task. For example, if the electric tailgate 100 is currently performing a closing task, step S414 continues to perform the closing task; if the electric tailgate 100 is currently performing an opening task, step S414 continues to perform the opening task.

[0059] Figure 5 A flowchart of an obstacle detection and control method 500 for an electric tailgate according to a second embodiment of this application is shown. Based on the magnitude of the motion angle, Figure 5 The detection and control method 500 shown divides the step of determining whether the electric tailgate 100 has encountered an obstacle into two stages, and adopts a different strategy for each stage to determine whether the electric tailgate 100 has encountered an obstacle based on the magnitude of the motor current used for the electric tailgate 100.

[0060] If the electric tailgate 100 encounters an obstacle during its movement, it will experience resistance, causing it to decelerate. This resistance will slow down the motor driving the tailgate 100, potentially causing it to stall. When using closed-loop control to manage the speed of the electric tailgate 100, the control voltage used to drive it increases accordingly in response to deceleration, aiming to overcome obstacle resistance and maintain the target speed. Since the stiffness of obstacles significantly affects the deceleration process, relying solely on speed reduction as a criterion for detecting obstacle encounters cannot guarantee the anti-pinch force of the tailgate 100. Considering that encountering an obstacle causes a sharp increase in motor current (meaning changes in motor current can reflect whether the tailgate 100 has encountered an obstacle), the detection and control method 500 of this application determines obstacle encounter based on current changes.

[0061] like Figure 5As shown, the detection and control method 500 includes steps S502 to S520. In step S502, the motion angle-based detection and control method 500 begins execution. In some embodiments, the motion angle-based detection and control method 500 begins execution when the electric tailgate 100 starts (e.g., to perform an opening or closing task). Once the motion angle-based detection and control method 500 begins, step S504 is executed to obtain the motion angle performed by the electric tailgate 100 since its start. Optionally, the motion angle of the electric tailgate 100 can be obtained by a Hall sensor mounted on the strut motor 210.

[0062] After step S504, step S506 is further executed to obtain the current of the strut motor 210. In some embodiments, the motor current can be sampled using an ammeter installed in the drive circuit 200. However, noise interference is inevitable during the sampling process of the motor current. Therefore, in some embodiments, the sampled motor current can be filtered. For example, software filtering can be applied to the sampled current to increase the accuracy of the data. Optionally, the filtered motor current at the current moment can be obtained based on the following formula: Current current filter value = Current current sample value × Current filter coefficient + Previous cycle current filter value × (1 - Current filter coefficient). Wherein, the smaller the current filter coefficient, the less noise interference. However, since a small filter coefficient will affect the accuracy of the current, the specific value of the current filter coefficient needs to be calibrated according to the actual situation. After step S506, step S508 is executed.

[0063] In step S508, it is determined whether the motion angle obtained in step S504 is greater than the critical motion angle. Referring to the description of the detection control method 400 above, the critical motion angle can be calibrated based on the first motion angle A and the second motion angle B. For example, the critical motion angle is the sum of the first motion angle A and the second motion angle B. Based on whether the angle value of the electric tailgate 100's motion since its start is greater than the critical motion angle, the detection control method 500 can use different judgment strategies to determine whether the electric tailgate 100 has encountered an obstacle.

[0064] If the movement angle of the electric tailgate 100 is not greater than the critical movement angle, step S514 is executed to determine whether the current of the strut motor 210 is greater than the critical current. In some embodiments, the critical current can be determined as follows: under multiple different operating conditions, the motor current I of the electric tailgate 100 at multiple specific opening angle positions is tested and recorded; for each specific opening angle position, the maximum current value among the multiple currents I under multiple operating conditions is taken, and a certain margin is added to the maximum current value to obtain the critical current; multiple critical currents are obtained corresponding to multiple specific opening angle positions, thus obtaining a set of critical currents calibrated based on the change in the opening angle position of the electric tailgate 100. That is, for a specific opening angle position, there is a calibrated critical current.

[0065] If the peak value of the motor current is greater than the critical current, it indicates that the electric tailgate 100 has encountered an obstacle. Step S516 is then executed to stop the electric tailgate 100's current movement and initiate a certain degree of reverse movement. If the peak value of the motor current is not greater than the critical current, it indicates that the electric tailgate 100 has not encountered an obstacle. The process then returns to step S508 to re-evaluate the electric tailgate 100's movement angle for subsequent obstacle detection.

[0066] If the movement angle of the electric tailgate 100 is greater than the critical movement angle, step S510 is executed to determine the current motor current increment ∆I based on the motor current obtained in step S506. In some embodiments, the current increment of the motor current may be the current increment of the electric tailgate 100 during a movement at a specific small angle, and the current current increment ∆I of the current motor current may be defined as the current motor current I when the electric tailgate 100 moves to the current opening angle position. 当前 The motor current I of the electric tailgate 100 at the previous opening angle position, which is the result of subtracting a certain small angle from the current opening angle position. 先前 The current difference between them. Optionally, the current increment ∆I of the current motor current is obtained by: obtaining the current opening angle position of the electric tailgate 100; subtracting a specific small angle value from the current opening angle position to obtain the previous opening angle position; and obtaining the current motor current I of the electric tailgate 100 corresponding to the current opening angle position. 当前 and the previous motor current I corresponding to the previous open angle position 先前 And the current motor current I 当前 Subtract the previous motor current I 先前 This allows us to obtain the current increment ∆I of the current motor current. In some embodiments, the specific small angle value can be the second motion angle B. For example, in other embodiments, the small angle value can also be other small angle values.

[0067] Following step S510, step S512 is further executed to determine whether the increment of the motor current obtained in step S510 is greater than the critical current increment. In some embodiments, the critical current increment can be obtained as follows: under multiple different operating conditions, the increase in motor current dI is recorded when the electric tailgate 100 moves to a specific opening angle position from the moment it encounters an obstacle until the force of the obstacle reaches the anti-pinch force. For each specific opening angle position, the maximum current increase among the multiple current increases dI under multiple different operating conditions is taken as the critical current increment. By obtaining multiple critical current increments corresponding to multiple specific opening angle positions, a set of critical current increments calibrated based on the change in the opening angle position of the electric tailgate 100 can be obtained. That is, for a specific opening angle position, there is a calibrated critical current increment.

[0068] It should be noted that because motor current and motor torque are linear, the increase in the support force of the tailgate strut 104 is also the same under the same current increment. Furthermore, since the force transmission ratio from the strut support force to the tailgate end varies with the angle, a calibration table of the current increment relative to the tailgate opening angle can be obtained. In some embodiments, the anti-pinch force detected based on the current change is essentially the same under different operating conditions, and the anti-pinch force of the electric tailgate 100 at each opening angle position can be modified using the current increment calibration table.

[0069] If the current increase of the motor current is greater than the critical current increase, it means that the electric tailgate 100 has encountered an obstacle, and then further execute step S516 to control the electric tailgate 100 to stop the current movement and perform a certain degree of reverse movement.

[0070] If the current increase in motor current is not greater than the critical current increase, it indicates that the electric tailgate 100 has not encountered an obstacle, and step S518 is executed to determine whether the electric tailgate 100 has completed this movement. If step S518 determines that the electric tailgate 100 has not completed this movement, the process returns to step S510 to obtain the current motor current increase again for subsequent obstacle detection and judgment. If step S518 determines that the electric tailgate 100 has completed this movement, step S520 is executed to end the obstacle detection control for this period.

[0071] Based on the characteristics of the electric tailgate 100, the embodiments of this application use the increase in motor current within a small angle (e.g., the second motion angle B) as the main criterion for determining whether the electric tailgate 100 has encountered an obstacle. This ensures that the anti-pinch force does not change significantly under different slopes, temperatures, or after system aging, resulting in better operational stability of the electric tailgate 100. For example, after the electric tailgate 100 reaches the critical motion angle defined by the sum of the first motion angle A and the second motion angle B, the change in current generated by the small-angle motion of the second motion angle B to the current tailgate opening position is mainly used to determine whether the electric tailgate 100 has encountered an obstacle. Because the value of the second motion angle B is small, the change in current caused by the electric tailgate 100 when executing the second motion angle B is small when the electric tailgate 100 has not encountered an obstacle. In other words, if the change in current increases sharply, it can be approximately considered to be caused by an obstacle.

[0072] In some embodiments, obstacle detection control for the same electric tailgate 100 can be implemented simultaneously using the detection control method 400 of the first embodiment and the detection control method 500 of the second embodiment. That is, this embodiment can simultaneously use three methods to detect obstacles, namely: based on the amount of movement of the electric tailgate 100 within the critical start time (i.e., the detection method of the detection control method 400), based on the peak current (i.e., the detection method corresponding to step S514 of the detection control method 500), and based on the current increase (i.e., the detection method corresponding to step S512 of the detection control method 500).

[0073] During the period before the electric tailgate 100 reaches a critical angle of movement, the magnitude of the anti-pinch force is uncertain, and it varies under different operating conditions. In this embodiment, the presence of an obstacle is determined during this period based on the peak current or the amount of movement of the electric tailgate 100 within the critical start-up time. It should be noted that the start-up time reaching the critical start-up time is merely a moment in the movement of the electric tailgate 100, and the movement angle being less than or equal to the critical angle is also only a relatively short period within the movement of the electric tailgate 100. Accordingly, scenarios where the electric tailgate 100 encounters an obstacle upon start-up are relatively rare.

[0074] For most of the time during its operation, the electric tailgate 100 moves at an angle greater than a critical angle. Once the electric tailgate 100 reaches the critical angle, the increase in current can be used to determine if an obstacle has been encountered. It is important to note that since anti-pinch protection primarily relies on the increase in current, when controlling the speed of the electric tailgate 100, it is crucial to ensure both a stable speed and a stable motor current, avoiding significant fluctuations and short-term spikes. Therefore, in some embodiments, methods such as... Figure 3 The filtering method described in the text for the theoretical output 316 effectively lays the foundation for anti-pinch protection by filtering the output voltage.

[0075] Therefore, it can be seen that the electric tailgate 100 can determine whether it has encountered an obstacle based on the current increment for most of the time during its movement. For situations where it is not suitable to use the current increment to determine whether an obstacle has been encountered, the embodiments of this application can also determine whether an obstacle has been encountered based on the start-up time and the current peak value, thus ensuring that the system can effectively prevent pinching under any operating conditions and at any time.

[0076] During obstacle detection, since the reverse current generated when braking the electric tailgate 100 does not produce an anti-pinch force, the current value in the drive motor can be considered zero when reverse current appears. Furthermore, because the electric tailgate 100 experiences different forces at different slopes, and the motor performance varies at different temperatures, and both the motor and mechanical transmission components age, the motor current of the drive motor will differ significantly under different operating conditions. Because these changes in external conditions cannot be fully perceived, simply relying on the current magnitude cannot accurately determine whether the electric tailgate 100 has encountered an obstacle. Even if the current peak value is used to determine if an obstacle has been encountered after a certain period of stalling, the magnitude of the anti-pinch force cannot be determined. However, once the electric tailgate 100 is running stably, as long as the speed control of the electric tailgate 100 is effective, the motor current will not suddenly increase significantly; it will only suddenly increase upon encountering an obstacle, and the amount of current increase is closely related to the resistance of the obstacle. This application has developed an obstacle detection method based on this characteristic, which can effectively detect whether the electric tailgate 100 has encountered an obstacle.

[0077] Next, combined Figure 6 This application describes a control system 600 for an electric tailgate according to one embodiment.

[0078] Figure 6A schematic diagram of a control system 600 for an electric tailgate according to an embodiment of this application is shown. The control system 600 includes a memory 602 and a processor 604. The memory 602 and the processor 604 are communicatively connected. The memory 602 is configured to store instructions, and the processor 604 is configured to execute the instructions stored in the memory 602, enabling the control system 600 to perform any of the control methods described above.

[0079] According to another aspect of this application, a computer-readable storage medium is provided, wherein instructions are stored that, when executed by a processor, cause the processor to perform any of the control methods for an electric tailgate described above. The computer-readable medium referred to in this application includes various types of computer storage media, and can be any available medium accessible by a general-purpose or special-purpose computer. For example, the computer-readable medium may include RAM, ROM, EPROM, E... 2 PROM, registers, hard disks, removable disks, CD-ROMs or other optical disc storage, magnetic disk storage or other magnetic storage devices, or any other temporary or non-temporary medium capable of carrying or storing desired units of program code in the form of instructions or data structures and accessible by a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor. As used herein, disks typically magnetically copy data, while discs optically copy data using lasers. Combinations of the above should also be included within the scope of computer-readable media. An exemplary storage medium is coupled to a processor so that the processor can read and write information from / to the storage medium. In an alternative, the storage medium may be integrated into the processor. The processor and storage medium may reside in an ASIC. The ASIC may reside in a user terminal. In an alternative, the processor and storage medium may reside as discrete components in the user terminal.

[0080] According to another aspect of this application, a vehicle is provided, the vehicle may include: an electric tailgate and a control system for the electric tailgate, wherein the control system may be any of the control systems 600 described above.

[0081] The control method and system of this application use the tailgate angular velocity to calibrate the speed of the electric tailgate 100, where the angular velocity mainly varies with the amount of movement of the tailgate. During most of the movement of the electric tailgate 100 in performing the starting or closing task, this application can use a feedforward plus feedback method to control the speed of the electric tailgate 100, and the feedforward voltage can be calibrated to a fixed value. Optionally, some embodiments of this application can use different PI coefficients to adjust the speed of the electric tailgate for different scenarios. During the soft stop of the electric tailgate, this application can use a tailgate soft stop strategy where the voltage decreases over time, where the slope of the voltage decrease over time can be determined through calibration. For the control voltage controlling the movement of the electric tailgate 100, the control voltage can be filtered before output, thereby avoiding speed fluctuations of the electric tailgate 100 and current fluctuations of the drive motor. In addition, the rate of change of voltage can be changed by calibrating the filter coefficient during the filtering process.

[0082] To further ensure the smooth operation of the electric tailgate 100, the control method of this application also includes obstacle detection during the movement of the electric tailgate. Specifically, after the electric tailgate 100 is running stably, obstacles can be detected based on the current increment within a calibrated angle, wherein the calibration of the current increment can vary with the opening angle position of the electric tailgate. In some embodiments, obstacles can also be detected based on the amount of movement of the electric tailgate 100 at the critical start time, wherein the critical start time and the critical movement angle used to determine whether an obstacle has been encountered can be calibrated. In other cases, obstacles can also be detected based on the current peak value, wherein the peak current of the electric tailgate 100 during opening and closing can be calibrated separately for the tailgate opening angle position. The control method and system of this application take into account the characteristics of different operating conditions during the operation of the electric tailgate 100, and formulate obstacle detection strategies adapted to various movement states, effectively ensuring the accuracy and reliability of obstacle detection and guaranteeing the smooth operation of the electric tailgate 100.

[0083] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Those skilled in the art can conceive of other feasible variations or substitutions based on the technical scope disclosed in this application, and such variations or substitutions are all covered within the scope of protection of this application. Where there is no conflict, the embodiments and features described in the embodiments of this application can also be combined with each other. The scope of protection of this application is determined by the claims.

Claims

1. A control method for an electric tailgate, characterized in that, The control method includes: During the movement of the electric tailgate from its starting position to its critical position, a proportional-integral control combined with feedforward control is used to control the speed of the electric tailgate. The critical position is the position where the electric tailgate has a remaining opening angle difference from completing its current movement. During the movement of the electric tailgate to achieve the remaining opening angle difference, the movement speed of the electric tailgate is controlled by decreasing the voltage over time. The method of controlling the movement speed of the electric tailgate using proportional-integral (PI) regulation combined with feedforward control includes: using a PI output voltage combined with a feedforward voltage as the control output voltage to control the movement speed of the electric tailgate, wherein the feedforward voltage is a calibrated value that does not change with angle and operating conditions. The control method further includes: determining whether the electric tailgate encounters an obstacle based on the motor current used for the electric tailgate, wherein determining whether the electric tailgate encounters an obstacle based on the motor current used for the electric tailgate includes: Obtain the movement angle of the electric tailgate; Obtain the motor current used for the electric tailgate; If the angle of motion is less than or equal to the critical angle of motion, it is determined whether the electric tailgate has encountered an obstacle based on whether the peak value of the currently acquired motor current is greater than the critical current; and If the angle of motion is greater than the critical angle of motion, it is determined whether the electric tailgate has encountered an obstacle based on whether the current increment ∆I of the currently acquired motor current is greater than the critical current increment.

2. The control method according to claim 1, wherein, The control method further includes calibrating target angular velocities for multiple different tailgate opening angles of the electric tailgate; and The control of the movement speed of the electric tailgate includes: controlling the angular velocity of the electric tailgate based on the calibrated target angular velocity corresponding to the plurality of different tailgate opening angles.

3. The control method according to claim 1, wherein, The method of controlling the movement speed of the electric tailgate by decreasing voltage over time includes: controlling the movement speed of the electric tailgate by decreasing voltage uniformly over time.

4. The control method according to claim 1, wherein, The remaining opening angle difference is less than or equal to 10°.

5. The control method according to claim 1, wherein, The proportional-integral control uses different proportional-integral coefficients under different operating conditions.

6. The control method according to claim 1, wherein, The control method further includes: When the start time of the electric tailgate reaches the critical start time, the movement angle of the electric tailgate is obtained; and Whether the electric tailgate encounters an obstacle is determined by judging whether the angle of motion of the electric tailgate at the critical start time is less than the critical angle of motion.

7. The control method according to claim 1, wherein, If the power tailgate encounters an obstacle, the power tailgate is controlled to perform a reverse movement.

8. The control method according to claim 6, wherein, The critical motion angle is determined based on the first motion angle A of the electric tailgate from start-up to when the motor current reaches stability under different operating conditions, and the second motion angle B of the electric tailgate from encountering an obstacle to when the force of the obstacle reaches the critical anti-pinch force under different operating conditions.

9. The control method according to claim 8, wherein, The critical start-up time is calibrated based on the time required for the electric tailgate to move to the sum of the first movement angle A and the second movement angle B under different operating conditions.

10. The control method according to claim 8, wherein, The current increment of the motor current is obtained in the following way: Subtract the second movement angle B from the current opening angle position of the electric tailgate to obtain the previous opening angle position; Obtain the current motor current I of the electric tailgate at the current opening angle position. 当前 And the previous motor current I corresponding to the previous opening angle position. 先前 ;and The current motor current I 当前 Subtract the previous motor current I 先前 .

11. A control system for an electric tailgate, characterized in that, The control system includes: Memory configured to store instructions; and A processor configured to execute the instructions causing the control system to perform the control method as described in any one of claims 1-10.

12. A computer-readable storage medium storing instructions, characterized in that, When the instruction is executed by the processor, the processor performs the control method as described in any one of claims 1-10.

13. A vehicle, characterized in that, The vehicles include: Electric tailgate; and The control system for the electric tailgate is the control system according to claim 11.

Images