Unattended turntable servo control system

Abstract

The invention discloses an unattended turntable servo control system. The method is applied to a two-dimensional rotary table, the rotary table comprises an azimuth rotating shaft and a pitching rotating shaft, and each rotating shaft is driven and controlled by a motor. The system comprises a control unit and a driving unit, the control unit is used for receiving the position information of the rotary table, the current information of each motor and a control instruction sent by external communication equipment, calculating a control signal required for driving each motor to a target position based on the received information, and sending the calculated control signal to the driving unit; and the driving unit generates a driving current based on the received control signal to drive the motors to rotate, so that each motor moves to a corresponding target position. According to the invention, free control of the rotary table under two degrees of freedom in the azimuth direction and the pitching direction can be autonomously realized.

Description

Technical Field

[0001] The present invention relates to the technical field of servo control, and particularly relates to an unattended turntable servo control system. Background Art

[0002] A turntable is a highly integrated device, which is usually used in application scenarios that require precise observation, identification, and tracking of distant targets.

[0003] Currently, in order to improve the flexibility of turntable control, especially to achieve the rotation control of the turntable under unattended conditions, it is urgent to develop a control system for an unattended turntable to achieve servo control of the turntable in two degrees of freedom, namely the azimuth direction and the pitch direction. Summary of the Invention

[0004] The present invention provides an unattended turntable servo control system, which can autonomously achieve free control of the turntable in two degrees of freedom, namely the azimuth direction and the pitch direction. The technical solution is as follows:

[0005] In a first aspect, an embodiment of the present invention provides an unattended turntable servo control system, which is applied to a two-dimensional turntable. The turntable includes an azimuth axis and a pitch axis, and each axis is driven and controlled by a motor respectively; the system includes: a control unit and a drive unit;

[0006] The control unit is configured to receive the position information of the turntable, the current information of each motor, and the control instructions sent by an external communication device, calculate the control signals required to drive each motor to the target position based on the received information, and send the calculated control signals to the drive unit;

[0007] The drive unit generates drive current based on the received control signals, drives the motors to rotate, so that each motor moves to the corresponding target position.

[0008] In a possible design, the control unit includes a first ARM chip and a second ARM chip, and the two ARM chips perform information interaction through an FMSC controller;

[0009] Among them, the first ARM chip is connected to the azimuth code disk, the pitch code disk of the turntable, and the external communication device, and is configured to receive the code disk information and control instructions, resolve the code disk information into the position information of the turntable, and send the position information and control instructions of the turntable to the second ARM chip; the second ARM chip is configured to receive the current of the motor, perform tracking calculation based on the current of the motor, the position information of the turntable, and the control instructions, to obtain the PWM control signals required to drive each motor to the target position, and send the calculated control signals to the drive unit.

[0010] In a possible design, the driving unit includes two driving chips, each driving chip is respectively connected to an ARM chip and a motor;

[0011] Each driving chip is respectively used to receive the control signal sent by the corresponding ARM chip, and generate a driving current based on the received control signal to drive the corresponding motor to move.

[0012] In a possible design, the driving unit further includes two current signal conditioning circuits, which are respectively connected to a driving chip; each current signal conditioning circuit is respectively used to convert the driving current signal generated by the corresponding driving chip into a voltage signal within a preset range, and send the voltage signal to the second ARM chip.

[0013] In a possible design, the voltage signal within the preset range is 0 - 3V.

[0014] In a possible design, the control unit further includes an ADC module, which is connected to each current signal conditioning circuit, and is used to convert the voltage signal sent by the current signal conditioning circuit from an analog signal into a digital signal.

[0015] In a possible design, each PWM control signal is respectively connected to the corresponding driving chip through optoelectronic isolation.

[0016] In a possible design, each motor is a permanent magnet synchronous motor; the second ARM chip generates a PWM control signal through the space vector control FOC method.

[0017] The embodiment of the present invention provides an unattended turntable servo control system. By setting a control unit and a driving unit, first, the control unit can receive the position information of the turntable, the current information of each motor, and the control instructions sent by an external communication device, and calculate the control signals required to drive each motor to the target position respectively based on the received information. Then, based on this control signal, the driving unit generates a driving current to drive the motor to rotate, so that each motor moves to the corresponding target position. It can be seen that this application does not require manual intervention. Only by setting the algorithm program between each unit, the information interaction relationship between each unit, and the communication relationship between each unit and the external communication device in advance, the automatic control of the turntable can be realized. It can be seen that this application integrates motor drive and control, and while reducing the production and R & D costs, it can achieve servo control of two degrees of freedom, azimuth and pitch. Description of the Drawings

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings required for the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can also be obtained based on these drawings.

[0019] Figure 1 is a schematic structural diagram of an unattended turntable servo control system provided by an embodiment of the present invention;

[0020] Figure 2 is a schematic structural diagram of a turntable provided by an embodiment of the present invention;

[0021] Figure 3 is a schematic flowchart of the space vector control method provided by an embodiment of the present invention. Specific Embodiments

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0023] The following describes the specific implementation manners of the above concepts.

[0024] Please refer to Figure 1 , an unattended turntable servo control system provided by an embodiment of the present invention is applied to a two-dimensional turntable. The turntable includes an azimuth axis and an elevation axis, and each axis is driven and controlled by a motor respectively;

[0025] The system includes: a control unit and a drive unit;

[0026] The control unit is configured to receive the position information of the turntable, the current information of each motor, and the control instructions sent by an external communication device, calculate the control signals required to drive each motor to the target position based on the received information, and send the calculated control signals to the drive unit;

[0027] The drive unit generates drive current based on the received control signals to drive the motors to rotate, so that each motor moves to the corresponding target position.

[0028] In this embodiment, first, the control unit receives the position information of the turntable, the current information of each motor, and the control instructions sent by the external communication device, and calculates the control signals required to drive each motor to the target position based on the received information. Then, based on the control signals, the drive unit generates drive currents to drive the motors to rotate, so that each motor moves to the corresponding target position. It can be seen that this application does not require manual intervention. Only by setting in advance the algorithm programs between the units, the information interaction relationships between the units, and the communication relationships between the units and the external communication device, the automatic control of the turntable can be achieved. It can be seen that this application integrates motor drive and control, and while reducing production and R & D costs, it can achieve servo control of two degrees of freedom, azimuth and pitch.

[0029] As Figure 2 shown, it is a schematic structural diagram of a two-dimensional turntable. It can be seen from the figure that the turntable consists of an azimuth axis system, a pitch axis system, a conductive slip ring, and a drive axis system. The structural form adopts a classic U-shaped structure, with a compact layout, good stiffness, and easy accuracy guarantee. The load (such as an optical sensor, etc.) is installed on the load bracket, and the load bracket is connected to both ends of the pitch axis system and rotates around the pitch axis. The azimuth axis system and the load are electrically connected through an optical-electrical slip ring to achieve 360° rotation of the azimuth.

[0030] As Figure 1 shown, the control unit includes a first ARM chip and a second ARM chip, and information interaction is carried out between the two ARM chips through an FMSC controller;

[0031] Among them, the first ARM chip is connected to the azimuth code disk, pitch code disk of the turntable, and the external communication device, and is used to receive the code disk information and control instructions, and resolve the code disk information into the position information of the turntable, and send the position information and control instructions of the turntable to the second ARM chip; the second ARM chip is used to receive the current of the motor, and perform tracking calculations based on the current of the motor, the position information of the turntable, and the control instructions to obtain the PWM control signals required to drive each motor to the target position, and send the calculated control signals to the drive unit.

[0032] It should be noted that the control instructions include the working mode, given value, and image information of the turntable; among them, the working mode at least includes: stop mode, positioning mode, speed mode, search mode, and tracking mode. The given value at least includes position given value, speed given value, motion amplitude given value, and frequency period given value. The image information includes the field of view, resolution, and image off-target amount of the optical sensor on the turntable.

[0033] In some embodiments, each ARM chip is an STM32F407 chip. In addition, the first ARM chip communicates with external devices through the RS422 interface and communicates with each encoder through the SPI module. The FMSC controller is a flexible static memory.

[0034] It should be noted that a mode switching algorithm is also set in the second ARM chip. This is because when the turntable is working, when the working mode changes from other modes to the tracking mode, if the switching is too fast, it will cause a short-term oscillation and it is easy to lose the target. Therefore, when it is necessary to switch the working mode of the turntable from a mode other than the tracking mode to the tracking mode, the following mode switching algorithm needs to be adopted:

[0035] S1, based on the current tracking box, select the moving target to be tracked, and execute S2;

[0036] S2, capture the image center of the current tracking box, determine the current image off-target amount based on the difference between the current image center and the preset position, and execute S3;

[0037] S3, judge whether the current image off-target amount is within the preset range. If not, maintain the current working mode and enter the next tracking, and return to execute S1; if so, execute S4;

[0038] S4, judge whether the delay counter has reached the preset value. If not, return to execute S1; if so, switch the current working mode to the tracking mode.

[0039] This algorithm is used to complete the process of switching from target capture to tracking. After each selection of a moving target by the tracking box, it first slowly captures the center. By judging whether the image off-target amount is within the preset range and the delay counter reaches the set value, and then switches to stable tracking, it can avoid the problem of short-term oscillation when switching from other modes to the tracking mode and improve the stability of tracking.

[0040] In some embodiments, the driving unit includes two driving chips, and each driving chip is respectively connected to an ARM chip and a motor;

[0041] Each driving chip is respectively used to receive the control signal sent by the corresponding ARM chip, and generate a driving current based on the received control signal to drive the corresponding motor to move.

[0042] Among them, the model of each drive chip is the intelligent power module IPM of Infineon, with the model number IGCM15F60. Each drive chip integrates a power switch device, a drive circuit, a protection circuit, a control circuit, and a heat dissipation device, improving the efficiency, reliability, and integration of motor drive. This IPM can achieve motor drive with a continuous working current less than 15A. In addition, the drive unit also includes two current signal conditioning circuits, which are respectively connected to a drive chip; each current signal conditioning circuit is respectively used to convert the drive current signal generated by the corresponding drive chip into a voltage signal within a preset range, and send the voltage signal to the second ARM chip. The voltage signal within the preset range is 0 to 3V.

[0043] In some embodiments, the control unit further includes an ADC module, which is connected to each current signal conditioning circuit and is used to convert the voltage signal sent by the current signal conditioning circuit from an analog signal to a digital signal.

[0044] In some embodiments, each PWM control signal is respectively connected to the corresponding drive chip through optoelectronic isolation.

[0045] In some embodiments, each motor is a permanent magnet synchronous motor; the second ARM chip generates a PWM control signal through the space vector control FOC method.

[0046] As Figure 3 shown, the working principle of the space vector control FOC method is specifically described below:

[0047] The essence of FOC is to use coordinate transformation to convert the motor phase current in the three-phase stationary coordinate system to the rotating coordinate system stationary relative to the rotor magnetic pole axis, and to control the motor by controlling the magnitude and direction of the vector in the rotating coordinate system. Specifically, after the FOC transformation, the three-phase currents on the U, V, and W of the motor are converted into the direct-axis current I D and the quadrature-axis I Q . After the FOC inverse transformation, the two-phase current is converted into three-phase current to control the motor. Since the angle between the rotating coordinate and the stationary coordinate axis is required during the Park transformation and the inverse Park transformation, the encoder information needs to enter both the FOC transformation and the FOC inverse transformation at the same time.

[0048] In summary, it can be seen that the servo control system of the present application is composed of a control unit and a drive unit. The control unit receives control instructions, generates control quantities through control algorithm operations, the drive unit generates motor drive current to drive the motor to operate, the motor drives the turntable to move, and an encoder is installed as an angle detection unit to perform speed and position feedback to ensure position servo accuracy. It has been verified that in the working state, the unattended turntable servo control system provided by the present application can achieve 360° continuous operation in the horizontal direction and movement from +80° to -15° in the pitch direction.

[0049] It can be seen that the present application can implement the hardware design of the servo control driver, with a wide expandable adaptation range and having important engineering application value.

[0050] Finally, it should also be noted that in this text, relational terms such as first, second, third, and fourth are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or device comprising the element.

[0051] The above are only the preferred embodiments of the present application. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present application, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present application.

Claims

1. An unattended turntable servo control system, characterized in that, Applied to a two-dimensional turntable, the turntable includes an azimuth axis and a pitch axis, and each axis is driven and controlled by a single motor respectively; The system includes: a control unit and a drive unit; The control unit is configured to receive the position information of the turntable, the current information of each motor, and the control instructions sent by an external communication device, calculate the control signals required to drive each motor to the target position respectively based on the received information, and send the calculated control signals to the drive unit; The drive unit generates drive currents based on the received control signals, drives the motors to rotate, so that each motor moves to the corresponding target position.

2. The system according to claim 1, wherein The control unit includes a first ARM chip and a second ARM chip, and information interaction is carried out between the two ARM chips through an FMSC controller; Among them, the first ARM chip is connected to the azimuth code disk, the pitch code disk of the turntable and the external communication device, and is used to receive the code disk information and control instructions, resolve the code disk information into the position information of the turntable, and send the position information and control instructions of the turntable to the second ARM chip; the second ARM chip is used to receive the current of the motor, and perform tracking calculations based on the current of the motor, the position information of the turntable and the control instructions, so as to obtain the PWM control signals required to drive each motor to the target position respectively, and send the calculated control signals to the drive unit.

3. The system according to claim 2, wherein The drive unit includes two drive chips, and each drive chip is respectively connected to an ARM chip and a motor; Each drive chip is respectively used to receive the control signals sent by the corresponding ARM chip, and generate drive currents based on the received control signals to drive the corresponding motor to move.

4. The system according to claim 3, wherein The drive unit further includes two current signal conditioning circuits, which are respectively connected to a drive chip; each current signal conditioning circuit is respectively used to convert the drive current signals generated by the corresponding drive chip into voltage signals within a preset range, and send the voltage signals to the second ARM chip.

5. The system according to claim 4, characterized in that, The voltage signals within the preset range are 0 to 3V.

6. The system according to claim 4, wherein The control unit further includes an ADC module, which is connected to each current signal conditioning circuit, and is used to convert the voltage signals sent by the current signal conditioning circuit from analog signals to digital signals.

7. The system according to claim 4, wherein Each PWM control signal is connected to the corresponding drive chip through opto-isolation.

8. The system according to claim 2, wherein Each motor is a permanent magnet synchronous motor; the second ARM chip generates PWM control signals through the space vector control FOC method.

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