Method for controlling multi-turn rotation of servo turntable in direction

Abstract

The invention discloses a direction multi-turn rotation control method for a servo turntable, which belongs to the technical field of automatic control, and mainly comprises the following steps: reading the current encoder value after the turntable rotates randomly, and calculating the current azimuth angle of the turntable by judging the relative initial zero position deviation value based on the initial zero position of the encoder; based on the current azimuth angle and the target azimuth angle of the turntable, calculating an encoder virtual value corresponding to the target azimuth angle according to a relative difference value of the two azimuth angles; finally, based on the encoder virtual value corresponding to the target azimuth angle, the servo motor drives the rotary table to rotate until the current encoder value is equal to the encoder virtual value set at the target position, and the rotation action is completed. According to the method, the mathematical relationship between the numerical value of any circle of rotation of the encoder and the actual physical azimuth angle of the rotary table is established, so that rapid calculation from the numerical value of the encoder to the azimuth angle of the rotary table is realized, and a solution is provided for the technical problem of continuous multi-circle rotation control of the servo rotary table.

Description

Technical Field

[0001] The invention belongs to the technical field of servo control, and in particular to a multi-turn rotation control method for a servo turntable. Background Art

[0002] Servo turntables are currently widely used in fields such as weapons and aerospace. Servo motors, as the common drive device for the turntable's rotational motion, rely on their powerful torque output to achieve the required azimuth rotation. Accurate control of servo motors requires high-precision encoders. Absolute encoders, due to their ability to retain position information after power failure, are widely used to measure the angular position signals of servo turntable motors. In actual use, the turntable rotates under the influence of the motor. Simultaneously, the encoder connected to the motor shaft continuously converts the shaft's angular displacement signals into electrical signals. This is then processed by the control module and converted into angular output. The control module then implements closed-loop azimuth rotation control based on the manually bound angular information. When servo turntables require high control accuracy, the encoder must accurately measure position in real time, while the servo control module must also rapidly process new commands.

[0003] As mission payloads develop towards functional diversification, the working conditions faced by servo turntables are becoming more complex, placing higher demands on the response speed and motion accuracy of the turntable servo control module. The single-turn rotation function of the servo turntable can no longer meet the usage requirements. When the turntable rotates a single turn, the pulse signal value output by the absolute encoder has a one-to-one correspondence with the physical azimuth angle of the turntable, and the azimuth angle can be effectively controlled based on the correspondence. However, when the turntable rotates n×360°, the absolute encoder pulse value gradually accumulates and exceeds the value range corresponding to a single turn. At this time, the servo control module cannot effectively output angle information, causing discontinuous angle control of the turntable. In view of the above status quo, solving the problem of multi-turn rotation control of the servo turntable direction is of great value to improving the stability of the turntable servo control. Summary of the Invention

[0004] The problem solved by the present invention is: for the control stability problem of continuous multi-turn rotation of a servo turntable, the present invention provides a servo turntable direction multi-turn rotation control method.

[0005] The technical solution to realize the present invention is:

[0006] A servo turntable multi-turn control method includes the following steps:

[0007] Step 1: Read the current encoder value after the turntable rotates any number of circles, determine the deviation of the current position relative to the zero position based on the encoder's initial zero position, and calculate the current turntable azimuth;

[0008] Step 2: Based on the current azimuth of the turntable and the target azimuth, calculate the encoder virtual value corresponding to the target azimuth according to the relative difference between the two azimuths;

[0009] Step 3: Based on the encoder virtual value corresponding to the target azimuth angle, the servo motor drives the turntable to rotate until the current encoder value is equal to the encoder virtual value corresponding to the target azimuth angle, completing the rotation action.

[0010] Furthermore, the encoder type is a single-turn absolute encoder.

[0011] Furthermore, the step 1 includes:

[0012] Step 101, calibrate the encoder value corresponding to the turntable physical orientation zero position as the encoder initial zero position x0;

[0013] Step 102: Divide the difference between the current encoder value after any rotation and the initial zero position by 360° and take the remainder to obtain the deviation of the current encoder value relative to the initial zero position, as follows:

[0014] M=[(x-x0)·360° / λ]%360° (1)

[0015] Where x is the encoder value corresponding to the current position of the turntable, λ is the number of pulses in each rotation cycle of the encoder, % is the modulo operator, and M is the deviation of the current encoder value from the initial zero position;

[0016] Step 103, based on the deviation of the encoder's current value from the initial zero position calculated in step 102, calculate the angle value of the turntable's positive direction relative to the azimuth zero position, that is, the current azimuth angle of the turntable:

[0017]

[0018] Where Y is the current azimuth angle of the turntable.

[0019] Furthermore, the step 2 specifically includes:

[0020] Step 201: Based on the current azimuth value of the turntable, the target azimuth of the turntable is input, and the difference between the target azimuth of the turntable and the current azimuth of the turntable is calculated as follows:

[0021] K=QY (3)

[0022] Among them, Q is the turntable target azimuth, and K is the difference between the two azimuths;

[0023] Step 202: Determine the difference range between the two azimuth angles and calculate the virtual value of the encoder when the turntable rotates to the target position. The formula is as follows:

[0024]

[0025] Among them, x k It is the virtual value of the encoder corresponding to the target azimuth position of the turntable.

[0026] Compared with the prior art, the present invention has the following significant advantages:

[0027] (1) The present invention solves the problem of arbitrary rotation control of the turntable within the range of n×360° by using a method of setting a virtual zero position of an absolute encoder to determine the azimuth angle after the turntable rotates an arbitrary circle. It has high versatility and can be applied to various styles of turntables using single-circuit absolute encoders.

[0028] (2) A mathematical relationship is established between the encoder value and the turntable azimuth angle of -180° to 180° in the form of a mathematical equation, which makes the turntable azimuth angle servo solution process respond faster and converge better. When the turntable rotates 360° continuously, the angle control is more accurate and the movement is smoother. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a flow chart of a servo turntable multi-turn control method according to an embodiment of the present invention.

[0030] Figure 2 Schematic diagram of the azimuth rotation angle range of the turntable according to an embodiment of the present invention.

[0031] Figure 3 Schematic diagram of the signal transmission flow of the servo control system.

[0032] Figure 4 This is a schematic diagram of the azimuth angle position of the encoder and the turntable after the turntable has rotated multiple times according to an embodiment of the present invention. DETAILED DESCRIPTION

[0033] The following is combined with Figures 1 to 3 The present invention is further described with reference to the accompanying drawings and specific embodiments.

[0034] The specific implementation is as follows:

[0035] like Figure 1 As shown, a servo turntable multi-turn control method includes the following steps:

[0036] Step 1: Read the current encoder value after the turntable rotates any circle, determine the current position relative to the zero position deviation based on the encoder's initial zero position, and calculate the current turntable azimuth.

[0037] Furthermore, the encoder type is a single-turn absolute encoder.

[0038] Furthermore, the step 1 includes:

[0039] Specifically, such as Figure 2 As shown, the turntable azimuth rotation limit is -180° to 180°, clockwise rotation is positive, and counterclockwise rotation is negative.

[0040] Furthermore, the encoder value corresponding to the turntable's physical orientation zero position is calibrated as the encoder's initial zero position x0;

[0041] Furthermore, the difference between the current value of the encoder after any rotation and the initial zero position is divided by 360° and the remainder is obtained to obtain the deviation of the current encoder value relative to the initial zero position:

[0042] M=[(x-x0)·360° / λ]%360° (1)

[0043] Where x is the encoder value corresponding to the current position of the turntable, λ is the number of pulses in each rotation cycle of the encoder, % is the modulo operator, and M is the deviation of the current encoder value from the initial zero position;

[0044] like Figure 3 As shown in the figure, the servo turntable system includes a control module, a power module, a turntable and a host computer. The turntable serves as a load module. The control module includes an encoder, a driver, a servo controller and a servo motor. The encoder is connected to the motor shaft and reads the angular displacement and angular velocity data of the motor shaft in real time. After signal processing, the position data is transmitted to the driver in real time. The communication protocol between the servo controller and the driver is CAN. The servo controller calibrates the initial zero position of the encoder through the driver and receives the current encoder value in real time. The external power module supplies direct current (DC) to the driver, converts it into alternating current (AC) and supplies it to the servo motor. The host computer communicates with the servo controller through the network port to transmit data. The host computer has a human-computer interaction function and can perform azimuth parameter binding and display the current azimuth information.

[0045] Furthermore, based on the deviation of the encoder's current value relative to the initial zero position, the angle value of the turntable's positive direction relative to the azimuth zero position, that is, the current azimuth angle of the turntable, is calculated to obtain:

[0046]

[0047] Where Y is the current azimuth angle of the servo turntable.

[0048] Step 2: Based on the current azimuth of the turntable and the target azimuth, calculate the encoder virtual value corresponding to the target azimuth according to the relative difference between the two azimuths;

[0049] Furthermore, based on the current azimuth value of the turntable, the target azimuth of the turntable is input, and the difference between the target azimuth of the turntable and the current azimuth of the turntable is calculated as follows:

[0050] K=QY (3)

[0051] Among them, Q is the turntable target azimuth, and K is the difference between the two azimuths;

[0052] Furthermore, the difference range of the two azimuth angles is determined, and the virtual value of the encoder when the turntable rotates to the target position is calculated. The formula is as follows:

[0053]

[0054] Among them, x k It is the virtual value of the encoder corresponding to the target azimuth position of the turntable.

[0055] Step 3: Based on the encoder virtual value corresponding to the target azimuth angle, the servo motor drives the turntable to rotate until the current encoder value is equal to the encoder virtual value corresponding to the target azimuth angle, completing the rotation action.

[0056] As an example:

[0057] Step 1: Read the current encoder value after the turntable rotates any number of circles, determine the deviation of the current position relative to the zero position based on the encoder's initial zero position, and calculate the current turntable azimuth;

[0058] Furthermore, in step 101, the encoder value corresponding to the zero position of the physical orientation of the turntable is calibrated as the initial zero position x0 of the encoder, assuming that the initial state is x0=2000;

[0059] Furthermore, based on the initial zero position calibrated in step 101, there is step 102, which calculates the difference between the current value of the encoder after any rotation and the initial zero position and divides the difference by 360 degrees to obtain the remainder, thereby obtaining the deviation of the current encoder value relative to the initial zero position. Further, it is assumed that the encoder reading after a certain number of rotations of the turntable is x = 50000;

[0060] Furthermore, the resolution of a single-turn absolute encoder is 12 bits, and the number of pulses in each rotation cycle is λ = 4096;

[0061] Then, according to formula (1), the encoder value deviation of the current position of the turntable relative to the initial zero position is calculated:

[0062] M=[(x-x0)·360° / λ]%360°=[(50000-2000)·360° / 4096]%360°=258.75°

[0063] Furthermore, the deviation M is determined to be in the range of 180°<258.75°<360°. According to formula (2), the current turntable azimuth is calculated as: Y=M-360°=258.75°-360°=-101.25°

[0064] Furthermore, step 2 is specifically as follows: based on the current azimuth angle of the turntable and the target azimuth angle, according to the relative difference between the two azimuth angles, calculating the encoder virtual value corresponding to the target azimuth angle;

[0065] Input target azimuth angle as Q = 45°;

[0066] Furthermore, step 201 is specifically as follows: the difference between the target azimuth angle of the turntable and the current azimuth angle of the turntable is calculated according to formula (3):

[0067] K=QY=45°-(-101.25°)=146.25°

[0068] Furthermore, step 202 is specifically as follows: determine that the difference between the target azimuth angle of the turntable and the current azimuth angle of the turntable is in the range of -180°≤146.25°≤180°. According to formula (4), the encoder value corresponding to the turntable rotating to the target angle can be calculated as: k =x+K·λ / 360°=50000+146.25°×4096 / 360°=51664;

[0069] Furthermore, the servo controller converts the encoder value signal x corresponding to the target azimuth angle of the turntable into k The data is transmitted to the driver. According to the calculation results, the motor drives the turntable to rotate clockwise. During the rotation process, the servo controller reads the current encoder value information in real time until the current encoder value x is equal to the encoder virtual value x set at the target position. k , the motor shaft stops rotating and completes the rotation action.

[0070] The above is the entire turntable azimuth rotation control process. Afterwards, when the servo controller receives new azimuth angle input data, it restarts the next closed-loop control according to the above process.

[0071] The protection scope of the present invention is not limited to the above. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed in the present invention should be included in the protection scope of the present invention.

Claims

1. A servo turntable multi-turn control method, characterized in that: Including steps: Step 1: Read the current encoder value after the turntable rotates any number of circles, determine the deviation of the current position relative to the zero position based on the encoder's initial zero position, and calculate the current turntable azimuth; Step 2: Based on the current azimuth of the turntable and the target azimuth, calculate the encoder virtual value corresponding to the target azimuth according to the relative difference between the two azimuths; Step 3: Based on the encoder virtual value corresponding to the target azimuth angle, the servo motor drives the turntable to rotate until the current encoder value is equal to the encoder virtual value corresponding to the target azimuth angle, completing the rotation action.

2. The method according to claim 1, characterized in that The encoder type is a single-turn absolute encoder.

3. The method according to claim 1, characterized in that The step 1 comprises: Step 101, calibrate the encoder value corresponding to the turntable physical orientation zero position as the encoder initial zero position x0; Step 102: Divide the difference between the current encoder value after any rotation and the initial zero position by 360° and take the remainder to obtain the deviation of the current encoder value relative to the initial zero position, as follows: M=[(x-x0)·360° / λ]%360° (1) Where x is the encoder value corresponding to the current position of the turntable, λ is the number of pulses in each rotation cycle of the encoder, % is the modulo operator, and M is the deviation of the current encoder value from the initial zero position; Step 103, based on the deviation of the encoder's current value from the initial zero position calculated in step 102, calculate the angle value of the turntable's positive direction relative to the azimuth zero position, that is, the current azimuth angle of the turntable: Where Y is the current azimuth angle of the turntable.

4. The method according to claim 1, wherein The step 2 specifically includes: Step 201: Based on the current azimuth value of the turntable, the target azimuth of the turntable is input, and the difference between the target azimuth of the turntable and the current azimuth of the turntable is calculated as follows: K=QY (3) Among them, Q is the turntable target azimuth, and K is the difference between the two azimuths; Step 202: Determine the difference range between the two azimuth angles and calculate the virtual value of the encoder when the turntable rotates to the target position. The formula is as follows: Among them, x k It is the virtual value of the encoder corresponding to the target azimuth position of the turntable.

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