Pan-tilt control device and method

Abstract

The present invention discloses a pan-tilt control device and method for matching the rotation speed and torque of a pan-tilt. The device includes a micro-control unit electrically connected to a pan-tilt controller, and is provided with a port expander for outputting pulse signals with different duty cycles at the port expander according to the motion trend of the pan-tilt; a filtering circuit electrically connected to the micro-control unit through the port expander for filtering the pulse signals to form different reference levels; a digital-to-analog converter electrically connected to the filtering circuit for converting the reference levels into digital level signals; a driving circuit electrically connected to a power supply and a driving motor for controlling the current of the driving motor; a pulse modulation circuit electrically connected to the digital-to-analog converter and the driving circuit for adjusting the current of the driving motor according to a target peak current; and a pan-tilt driving motor electrically connected to the driving circuit and the pulse modulation circuit for driving the pan-tilt. The present invention can avoid excessive power consumption when the pan-tilt is locked, and motor out-of-step caused by insufficient torque when the rotation speed is increased, etc.

Description

Technical Field

[0001] The present invention belongs to the technical field of pan-tilt control, and relates to a pan-tilt control device and method. Background Art

[0002] A pan-tilt can be a support device for mounting and fixing a mobile phone, camera, video camera, or camera. The pan-tilt can rotate arbitrarily, facilitating use by the user. Among them, an electric pan-tilt for mounting a video camera or camera generally uses a stepper motor to control the pan-tilt, enabling the pan-tilt to control the stepper motor according to a preset program, causing the pan-tilt to perform horizontal and vertical rotations at a fixed rotation angle, thereby driving the video camera to align with the target scene to be photographed within a certain range, so as to collect image data for multi-directional scene monitoring, and this image data is generally video.

[0003] In the related art, for the control of an electric pan-tilt of a general security camera, during the startup process, operation acceleration, deceleration process, and prohibition and locking process, the current of the motor is constant, which easily leads to problems such as the motor losing steps during rotation, the belt slipping and wearing, and excessive power consumption during locking, reducing the repeated positioning accuracy of the pan-tilt and shortening the service life of the mechanical structure of the pan-tilt. How to adjust the target peak current of the motor of the electric pan-tilt to match the above-mentioned various processes has always been an important research direction for those skilled in the art. Summary of the Invention

[0004] A first aspect of the present invention aims to solve the technical problems existing in the above-mentioned related art, and provides a pan-tilt control device, which is characterized in that a micro-control unit is electrically connected to a controller, and is provided with a port expander for outputting pulse signals with different duty cycles at the port expander according to the movement trend of the pan-tilt, and the pulse signals represent the target peak current matching the movement trend of the pan-tilt; a filter circuit is electrically connected to the micro-control unit through the port expander for filtering the pulse signals to form different reference levels; a digital-to-analog converter is electrically connected to the filter circuit for converting the reference levels into analog level signals; a drive circuit is electrically connected to a power supply and a drive motor for controlling the current of the drive motor; a pulse modulation circuit is electrically connected to the digital-to-analog converter and the drive circuit for adjusting the current of the drive motor according to the target peak current; and a drive motor is electrically connected to the pulse modulation circuit through the drive circuit for driving the pan-tilt.

[0005] Preferably, the Fourier series representation of the pulse signal is:

[0006]

[0007] where μ is the duty cycle of the pulse signal, T is the period of the pulse signal, t is the time variable, V p is the voltage peak value of the pulse signal output by the micro-control unit, and k≥2 and is an integer.

[0008] In any of the above solutions, preferably, the filter circuit is a second-order filter circuit, including a first-order filter circuit formed by connecting a first resistor and a first capacitor in series, and a second-order filter circuit formed by connecting a second resistor and a second capacitor in series. The first-order filter circuit and the second-order filter circuit are connected in series.

[0009] In any of the above solutions, preferably, the first resistor is equal to the second resistor, and the first capacitor is equal to the second capacitor.

[0010] In any of the above solutions, preferably, an overcurrent protection circuit is electrically connected between the power supply and the drive circuit.

[0011] The second aspect of the present invention provides a pan-tilt control method, which uses the pan-tilt control device as described in the first aspect and any one of the preferred embodiments, and includes the following steps:

[0012] The microcontroller unit obtains the motion trend of the pan-tilt from the controller. The motion trend includes pan-tilt locking, starting acceleration, and starting deceleration;

[0013] The microcontroller unit outputs a pulse signal with a target duty cycle based on the motion trend through the port expander. The pulse signal represents the target peak current matching the motion trend of the pan-tilt;

[0014] The filter circuit filters the pulse signal to form a reference level;

[0015] The pulse modulation circuit adjusts the current of the drive motor according to the reference level to match the target peak current of the motion trend.

[0016] Preferably, the Fourier series representation of the pulse signal is:

[0017]

[0018] where μ is the duty cycle of the pulse signal, T is the period of the pulse signal, t is the time variable, V p is the voltage peak value of the pulse signal output by the microcontroller unit, and k≥2 and is an integer.

[0019] In any of the above solutions, preferably, the microcontroller unit determines the motion trend of the pan-tilt according to the S-shaped speed curve of the motor.

[0020] In any of the above solutions, preferably, when the pan-tilt is stationary and locked, the value of the target peak current is 1 / 2 of the maximum current value for driving the drive motor.

[0021] Through the above design, the present invention can at least achieve the following beneficial effects:

[0022] The pan-tilt control device and method of the present invention. The micro-control unit obtains the motion trends of the pan-tilt, such as locking, starting to accelerate, and starting to decelerate, and then outputs a pulse signal with a target duty cycle based on the motion trends. The drive control circuit of the motor compares and controls the current of the connected power supply based on the pulse signal with the target duty cycle, so that the current reaching the motor matches the motion trend of the motor, avoiding excessive power consumption when the pan-tilt is locked and motor out-of-step caused by insufficient torque when the rotation speed increases, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a schematic structural diagram of an embodiment of the pan-tilt control device of the present invention;

[0024] Figure 2 is a schematic flowchart of an embodiment of the pan-tilt control method of the present invention;

[0025] Figure 3 is a schematic flowchart of another embodiment of the pan-tilt control method of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] To make the objectives, technical solutions and advantages of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0027] In addition, in the description of the present invention, the orientation or positional relationships indicated by the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present invention rather than requiring the present invention to be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. The terms "connected" and "coupled" used in the present invention should be understood in a broad sense. For example, they can be fixedly connected or detachably connected; they can be directly connected or indirectly connected through intermediate components. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific circumstances.

[0028] In the related art, an electric pan-tilt for installing a camera generally uses a motor to control the pan-tilt, so that the pan-tilt rotates horizontally and vertically by a fixed rotation angle according to a step design, thereby driving the camera to align with the target scene to be photographed within a certain range and collecting multi-directional scene monitoring images. When the motor starts and stops, there will be a step change in speed, which will affect the motor itself due to the sudden change in motor speed; a large force will be generated due to inertia at the start and stop moments, resulting in current overload. Usually, acceleration and deceleration control algorithm strategies are used to plan the motor speed. Common acceleration and deceleration control algorithm strategies include trapezoidal acceleration and deceleration control strategies and S-shaped curve control algorithms.

[0029] The trapezoidal acceleration and deceleration control strategy is easy to implement, but its acceleration is discontinuous, and there is a sudden change at the junction between the acceleration stage and the constant-speed stage, which will cause an impact on the motor body. The S-curve control algorithm is another commonly used acceleration and deceleration control strategy in the industrial control field. The S-curve control algorithm well overcomes the problem of discontinuous acceleration of the trapezoidal curve. It actually realizes a trapezoidal change process of acceleration, specifically, a process of increasing acceleration, constant acceleration, and decreasing speed. During the entire speed adjustment process, the acceleration changes continuously, and the reflected speed change is a smooth S-shaped speed curve. The S-shaped speed curve divides the entire motion process into 7 stages, namely, the jerk acceleration stage, the uniform acceleration stage, the jerk deceleration stage, the constant-speed stage, the acceleration and deceleration stage, the uniform deceleration stage, and the jerk deceleration stage. The speed connection in different stages is continuous, and the change rate of acceleration is controllable, solving the problem of sudden acceleration change existing in the trapezoidal acceleration and deceleration control strategy. The S-curve control algorithm can be stored in the motor controller of the motor controlling the movement of the pan-tilt in the form of program control, and the controller can output the data of any point on the corresponding S-curve.

[0030] Although the S-curve control algorithm in the above related technologies solves the problem that the speed will have a step during the start and stop of the motor, in the process of controlling the rotation of the pan-tilt, the current power consumption of the general motor cannot be dynamically adjusted. That is, in the start process, the running acceleration, deceleration process, and locking process of the general security camera electric pan-tilt in the current industry, the current value of the motor of the pan-tilt remains unchanged. Due to the lack of corresponding dynamic adjustment operations for the current of the motor, it is easy to cause problems such as the motor rotation out of step, the belt slipping and wearing, and excessive power consumption during locking, reducing the repeated positioning accuracy and mechanical service life of the pan-tilt.

[0031] The purpose of the embodiment of the first aspect of the present invention is to solve the problems existing in the above related technologies, and provide a pan-tilt control device for controlling the current of the pan-tilt drive motor 7 when the pan-tilt is locked, starting to accelerate, and starting to decelerate, etc., so as to achieve the effect of controlling the rotation torque and power consumption matching.

[0032] Figure 1 It is a schematic structural diagram of an embodiment of the pan-tilt control device of the present invention, as Figure 1As shown, the pan-tilt control device of this embodiment may include a microcontroller unit 1 (Microcontroller Unit; MCU), a filter circuit 2, a digital-to-analog converter 3, and a pulse modulation circuit 5. Among them, the microcontroller unit 1 can be electrically connected to the controller of the pan-tilt. The microcontroller unit 1 can be provided with a port expander 11 (General-purpose input / output, GPIO). The microcontroller unit 1 can be used to output pulse signals with different duty cycles at the port expander 11 according to the movement trend of the pan-tilt. The pulse signal represents the target peak current matching the movement trend of the pan-tilt. In this embodiment, the movement trend of the pan-tilt can be obtained according to the S-shaped speed curve read from the controller. The specific S-shaped movement curve can be preset or stored in the controller of the pan-tilt. This embodiment does not specifically limit the acquisition method of the S-shaped speed curve. Among them, the movement trend of the pan-tilt can be determined according to the acceleration in the S-shaped speed curve. For example, during the start-up acceleration process of the pan-tilt, the acceleration gradually increases; during the start-up deceleration process, the acceleration gradually decreases; during the uniform rotation process, the acceleration is 0.

[0033] The controller of the pan-tilt can be a manual controller or an automatic controller. However, in any case, it is the controller that issues instructions to control the locking, start-up acceleration, and start-up deceleration of the pan-tilt. The microcontroller unit 1 can determine the magnitude of the current required to control the driving motor 7 when the controller issues commands for the pan-tilt to accelerate rotation, decelerate, or lock, and generate corresponding pulse signals.

[0034] In this embodiment, the filter circuit 2 can be electrically connected to the microcontroller unit 1 through the port expander 11, and is used to filter the pulse signal to form different reference levels. The digital-to-analog converter 3 can be electrically connected to the filter circuit 2, and this digital-to-analog converter 3 is used to convert the reference level into an analog level signal. The microcontroller unit 1 can output a pulse signal matching the corresponding movement trend. This pulse signal can be a pulse signal of pulse width modulation (Pulse width modulation, PWM) with different duty cycles according to the output of the port expander 11 of the microcontroller unit 1, and then form different reference levels "VREF" for the digital-to-analog converter 3 (Digital to analog converter, DAC) through the second-order filter circuit 2 correspondingly. In this embodiment, the digital-to-analog converter is used to convert the electrical signal into an analog signal, which can more intuitively understand the magnitude of the level signal and achieve more accurate control of the reference level.

[0035] After the micro - control unit 1 determines the magnitude of the current required by the driving motor 7, it generates a pulse signal and outputs the pulse signal through the port expander 11. The pulse signal forms different reference levels through the filter circuit 2, and different reference levels respectively correspond to the pan - tilt locking, starting acceleration, and starting deceleration states. That is to say, a variety of different reference levels are not obtained simultaneously. For a current motion state of the pan - tilt, the micro - control unit 1 can only output one pulse signal.

[0036] The driving circuit 4 can be electrically connected to the power supply 6 and the pan - tilt driving motor 7 to control the current of the driving motor 7; the pulse modulation circuit 5 can be electrically connected to the digital - to - analog converter 3 and the driving circuit 4 to adjust the current of the driving motor 7 according to the target peak current. In one example, the driving circuit can be an RV8825 driving chip. The pan - tilt driving motor 7 is electrically connected to the driving circuit 4 and the pulse modulation circuit 5 to drive the pan - tilt. In this embodiment, the digital - to - analog converter 3 is electrically connected to the pulse modulation circuit 5, and the analog level signal transmitted to the pulse modulation circuit 5 through the digital - to - analog converter 3 interferes with the current in the driving circuit 4, so that the peak current of the power supply 6 passing through the driving circuit 4 matches the motion trend of the pan - tilt. During the static locking, starting process, stopping process, running acceleration, and running deceleration processes of the pan - tilt, the peak current of the driving motor 4 can be dynamically adjusted to achieve a matching rotational torque and power consumption, so as to achieve precise control of the motion of the pan - tilt. If the peak current during the starting process and the running acceleration process is the maximum current provided by the driving circuit 4, then during the delicate locking, stopping process, and running deceleration process of the pan - tilt, the effect of reducing power consumption can also be achieved.

[0037] In some embodiments, a filter circuit 2 is provided between the port expander 11 and the digital - to - analog converter 3. The pulse signal output by the port expander 11 can be expressed by the Fourier series as

[0038]

[0039] where μ is the duty cycle of the pulse signal, T is the period of the pulse signal, t is the time variable, and V p is the voltage peak value of the pulse signal output by the micro - control unit 1, and k≥2 and is an integer. The above expression is the principle expression of the time - domain signal of the pulse signal output by the micro - control unit 1 through frequency - domain decomposition, so that the subsequent filter circuit 2 can extract the DC component to achieve the control effect. The filter circuit 2 in this embodiment can be a second - order filter circuit 2, including a first - order filter circuit 2 formed by connecting a first resistor and a first capacitor in series, and a second - order filter circuit 2 formed by connecting a second resistor and a second capacitor in series. The first - order filter circuit 2 and the second - order filter circuit 2 are connected in series.

[0040] Such as Figure 1The shown filter circuit 2 can obtain the DC level component VREF through the filter circuit 2 after selecting appropriate parameter settings to filter out high-frequency signals when the two resistors and two capacitors in the figure are the same. Moreover, the larger the duty cycle μ, the larger VREF, which is approximately linearly proportional. Among them, the duty cycle refers to the proportion of the energization time relative to the total time within a pulse cycle. The cut-off frequency required to filter out high-frequency components can be obtained through the Fourier expression in the frequency domain, and this cut-off frequency is related to the output frequency when designing PWM.

[0041] The digital-to-analog converter 3 can be connected to the pulse modulation circuit 5 to transmit the analog level signal obtained by converting the reference level through the digital-to-analog converter 3 to the pulse modulation circuit 5. The pulse modulation circuit 5 is connected between the drive circuit 4 and the above digital-to-analog converter 3, and controls the current transmitted to the drive motor 7 by receiving the analog level signal to be applicable to different motion trends such as locking, starting acceleration, and starting deceleration of the drive motor 7 for driving the pan-tilt.

[0042] The digital-to-analog converter 3 converts the digital signal into an analog signal to determine the peak current required by the drive motor 7 in the current pan-tilt motion state. Based on the analog signal of the digital-to-analog converter 3 received, the pulse modulation circuit 5 compares the current of the current drive motor 7 to determine whether to increase or decrease the current value passing through the drive motor 7, and determines the peak current suitable for the pan-tilt motion trend based on the analog signal of the digital-to-analog converter 3. If the current is small, the current is increased; if the current is large, the current is decreased. That is to say, the device added to the drive circuit 4 provided in this embodiment essentially adapts to various motion states of the pan-tilt by changing the current value applied to the drive motor 7 by the power supply 6.

[0043] Specifically, in the pan-tilt locked state, using the pan-tilt control device of this embodiment can automatically control the current of the pan-tilt drive motor to satisfy the position offset caused by general vibrations of the pan-tilt. For example, the current of the pan-tilt motor can be set to 1 / 2 of the maximum operating value, which can meet the application of power consumption reduction. During the S-curve control of the pan-tilt or the process of the pan-tilt rotating and accelerating or decelerating, the corresponding current value that meets the load torque condition can be set according to the current characteristic curve of the speed and torque of the drive motor itself. The specific value in the actual process can be dynamically adjusted according to the rotation speed, which can better avoid the out-of-step of the pan-tilt drive motor during acceleration and improve the positioning accuracy, as well as reduce the power consumption after deceleration.

[0044] Based on the same or similar design concept, the second aspect of the embodiments of the present invention provides a pan-tilt control method, using the pan-tilt control device involved in any one of the above first aspect and its preferred embodiments. Figure 2 is a schematic flowchart of an embodiment of the pan-tilt control method of the present invention. As Figure 2 shown, the pan-tilt control method of this embodiment can include the following steps:

[0045] S1: The micro - control unit 1 obtains the motion trend of the pan - tilt from the controller of the pan - tilt. The motion trend includes pan - tilt locking, starting acceleration, and starting deceleration;

[0046] S2: The micro - control unit 1 outputs a pulse signal with a target duty cycle based on the motion trend through the port expander 11. The pulse signal represents the target peak current matching the motion trend of the pan - tilt;

[0047] S3: The filter circuit 2 filters the pulse signal to form a reference level; the pulse modulation circuit 5 adjusts the current of the driving motor according to the reference level to match the target peak current of the motion trend.

[0048] Among them, the Fourier series of the pulse signal can be expressed as:

[0049]

[0050] Among them, μ is the duty cycle of the pulse signal, T is the period of the pulse signal, t is the time variable, V p is the peak voltage of the pulse signal output by the micro - control unit 1, and k≥2 and is an integer.

[0051] In some embodiments, the micro - control unit 1 determines the motion trend of the pan - tilt according to the S - type speed curve of the motor. When the pan - tilt is stationary and locked, the value of the target peak current can be 1 / 2 of the maximum current value for driving the driving motor. The value of the target peak current can be obtained by the pulse modulation circuit 5 interfering with the current in the driving circuit 4. Among them, the pulse modulation circuit 5 can compare the peak current matching the motion trend of the pan - tilt with the current in the driving circuit 4 and determine the peak current of the driving circuit 4 matching the motion trend of the pan - tilt.

[0052] In the pan - tilt control method of the embodiment of the present invention, the micro - control unit 1 obtains the motion trends of locking, starting acceleration, and starting deceleration of the pan - tilt, and thus outputs a pulse signal with a target duty cycle based on the motion trend. The pulse modulation circuit 5 performs comparison control on the current of the power supply 6 connected to the driving circuit 4 based on the above - mentioned pulse signal with the target duty cycle, so that the peak current reaching the driving motor 7 matches the motion trend of the pan - tilt, avoiding excessive power consumption when the pan - tilt is locked and motor out - of - step caused by insufficient torque when the rotation speed increases.

[0053] Figure 3It is a schematic flowchart of another embodiment of the pan-tilt control method of the present invention. Determine whether the pan-tilt is in a locked state. If the pan-tilt is in a locked state, the micro-control unit 1 generates a PWM pulse signal with a relatively large duty cycle by obtaining the pan-tilt movement trend of the S-shaped speed curve in the controller of the pan-tilt, and transmits it to the filter circuit 2 through the port expander 11. After being filtered by the second-order filter circuit 2, a reference level "VREF" is correspondingly formed and given to the digital-to-analog converter 3. The digital-to-analog converter 3 transmits the obtained analog level signal to the pulse modulation circuit 5. The pulse modulation circuit 5 compares the obtained analog level signal with the current value in the drive circuit 4, and interferes with the current in the drive circuit 4 connected to the power supply 6 to maintain it at half of the maximum current value, so as to maintain general jitter and displacement of the pan-tilt. If the pan-tilt is not in a locked state, continue to determine whether the pan-tilt is in a starting acceleration state. If it is in a starting acceleration state, adjust the peak current of the drive circuit 4 according to the S-shaped speed curve of the pan-tilt to meet the rotational speed of the drive motor corresponding to the load torque. If it is not in a starting acceleration state, further determine whether it is in a starting deceleration state. If it is in a starting deceleration state, after the rotational speed of the drive motor drops to the target speed, adjust the peak current of the drive circuit 4 according to the foregoing control idea to meet the rotational speed of the drive motor corresponding to the load torque. If it is not in a starting deceleration state, re-determine whether the pan-tilt is in a locked state.

[0054] By using the pan-tilt control device involved in the above first aspect and each preferred embodiment, the peak current of the drive circuit 4 is adjusted based on the movement trend of the pan-tilt for the peak current of the drive motor 7 of the pan-tilt, and the peak current of the drive motor 7 can be dynamically adjusted during the static locking, starting process, stopping process, running acceleration, and deceleration processes of the pan-tilt, so as to achieve the effect of relatively ideal rotational torque and power consumption matching, and extend the service life of the drive motor.

[0055] As is known by technical common sense, the present invention can be implemented by other embodiments without departing from its essence or necessary features. Therefore, the above-disclosed embodiments are illustrative in all aspects and are not the only ones. All changes within the scope of the present invention or within the scope equivalent to the present invention are encompassed by the present invention.

Claims

1. A pan-tilt control device, characterized in that, it includes: A micro-control unit (1), electrically connected to the controller of the pan-tilt, is provided with a port expander (11), which is used to output pulse signals with different duty cycles at the port expander (11) according to the movement trend of the pan-tilt, and the pulse signals represent the target peak current matching the movement trend of the pan-tilt; A filter circuit (2), electrically connected to the micro-control unit (1) through the port expander (11), is used to filter the pulse signals to form different reference levels; A digital-to-analog converter (3), electrically connected to the filter circuit (2), is used to convert the reference level into an analog level signal; A drive circuit (4), electrically connected to the power supply (6) and the drive motor (7), is used to control the current of the drive motor (7); A pulse modulation circuit (5), electrically connected to the digital-to-analog converter (3) and the drive circuit (4), is used to adjust the current of the drive motor (7) according to the target peak current; A drive motor, electrically connected to the pulse modulation circuit (5) through the drive circuit (4), is used to drive the pan-tilt.

2. The pan-tilt control device according to claim 1, characterized in that, The Fourier series of the pulse signal is expressed as: where μ is the duty cycle of the pulse signal, T is the period of the pulse signal, t is the time variable, Vp is the voltage peak of the pulse signal output by the micro-control unit (1), and k≥2 and is an integer.

3. The pan-tilt control device according to claim 2, characterized in that, The filter circuit (2) is a second-order filter circuit, including a first-order filter circuit formed by a first resistor and a first capacitor in series, and a second-order filter circuit formed by a second resistor and a second capacitor in series, and the first-order filter circuit and the second-order filter circuit are in series.

4. The pan-tilt control device according to claim 3, characterized in that, The first resistor is equal to the second resistor, and the first capacitor is equal to the second capacitor.

5. The pan-tilt control device according to claim 4, characterized in that, An overcurrent protection circuit is electrically connected between the power supply (6) and the drive circuit (4).

6. A pan-tilt control method, characterized in that, using the pan-tilt control device according to any one of claims 1 to 5, includes the following steps: The micro-control unit (1) obtains the movement trend of the pan-tilt from the controller, and the movement trend includes pan-tilt locking, starting acceleration, and starting deceleration; The micro-control unit (1) outputs a pulse signal with a target duty ratio based on the movement trend through the port expander (11), and the pulse signal represents the target peak current matching the movement trend of the pan-tilt; The filter circuit (2) filters the pulse signal to form a reference level; The pulse modulation circuit (5) is electrically connected to the digital-to-analog converter (3) and the drive circuit (4), and adjusts the current of the drive motor (7) according to the target peak current, so that the peak current reaching the drive motor (7) matches the movement trend of the pan-tilt.

7. The pan-tilt control method according to claim 6, characterized in that, The Fourier series of the pulse signal is expressed as: Wherein, μ is the duty cycle of the pulse signal, T is the period of the pulse signal, t is the time variable, Vp is the voltage peak value of the pulse signal output by the micro control unit (1), and k≥2 and is an integer.

8. The pan-tilt control method according to claim 6, characterized in that, the micro control unit (1) determines the movement trend of the pan-tilt according to the S-shaped speed curve of the motor.

9. The pan-tilt control method according to claim 8, characterized in that, when the pan-tilt is statically locked, the value of the target peak current is 1 / 2 of the maximum current value for driving the driving motor (7).

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