Pitching limiting motion control method for photoelectric turret

Abstract

The invention provides a pitching limiting motion control method for a photoelectric turret. The pitching limiting motion control method comprises the following steps: acquiring a pitching limiting position and a head-up position C of the photoelectric turret based on data measured by an encoder; the deceleration section is arranged at the limiting position, so that the angular velocity of the pitch shaft moving from the starting point of the deceleration section to the limiting position is zero, and the pitch shaft is prevented from impacting the arc-shaped limiting groove of the limiting device; setting a deceleration factor K at different positions of the deceleration section according to the pitch axis angle electrical zero crossing point; the angular velocity direction of the pitch axis is set, so that the pitch axis does not perform decelerating motion when moving out of the decelerating section. The problem that when the high rotating speed of a traditional photoelectric turret is directly and suddenly reduced to 0 from the high rotating speed, the traditional photoelectric turret possibly rushes over the limiting position due to inertia is solved, a uniform and mild speed reduction method for gradually reducing the speed to 0 from the high rotating speed is adopted, the use requirement of the photoelectric turret is better met, and a limiting device can be better protected.

Description

Technical Field

[0001] The invention belongs to the technical field of photoelectric turret limit control, and in particular relates to a photoelectric turret pitch limit motion control method. Background Art

[0002] The optoelectronic turret is a device that can search and detect targets during the day and night. It can realize rotational movement in azimuth and elevation directions. Generally, the azimuth axis can realize a 360° rotation, while the elevation axis can move within a limited angular range.

[0003] At present, the pitch limit of some optoelectronic turrets is realized only by using the limit structure, relying on the impact resistance of the mechanical structure for braking. When the motor speed is high, the structural parts may be deformed due to the impact. For example, a protective stable platform frame limit device disclosed in the Chinese patent with the authorization number CN104406587B is composed of two limit bases, two limit baffles, a drive mechanism rotor pin and four limit fixing bolts. This type of device has a complex structure and a large volume, and is not suitable for the limited space of the pitch component of the optoelectronic turret. The pitch limit of another part of the optoelectronic turret is realized only by software control. For example, the Chinese patent with the application number CN115036695A discloses a method for antenna software limit protection, which performs the limit by comparing the real-time reading of the antenna axis angle with the limit value in the software. For this method that relies solely on software limit, when the angle sensor fails or the angle solution is wrong, it will cause the limit to fail, and then cause the device to lose control and cause serious consequences. Therefore, it is necessary to design a method that combines the software's electrical limit with the mechanical structure limit to form a two-layer limit mechanism to achieve limit control of the optoelectronic turret.

[0004] Most of the existing limit motion control methods that combine software and hardware directly shut down the drive of the stable platform after judging that the frame angle reaches the electrical limit. For example, the Chinese patent with application number CN109491404A discloses a limit protection method for a servo stable platform, which shuts down the servo drive by judging the frame angle value of the guide head and the polarity of the main command signal. This method can achieve effective multi-layer limit control of the pitch axis of the optoelectronic turret. However, this method does not take into account the inertial motion of the machinery and the hysteresis of the servo control. When the frame angle value reaches the limit position, the servo drive is suddenly shut down. Due to the inertial motion of the mechanical axis and the time lag of the servo system, it takes a certain amount of time to reduce the speed to zero. Therefore, when the motor speed is too high, the motor may not stop rotating when it reaches the limit position, or even rush through the limit position, damaging the device. Summary of the invention

[0005] The purpose of the present invention is to solve the problem that the existing limit motion control does not take into account mechanical inertia and control delay, and the speed of the device at the limit position may not drop to 0 and damage the device, and provide an optoelectronic turret pitch limit motion control method.

[0006] To achieve the above purpose, the technical solution provided by the present invention is:

[0007] A method for controlling the pitch limit motion of an optoelectronic turret comprises the following steps:

[0008] Step 1: Based on the horizontal position C set by the optoelectronic turret and the requirements for the upward and downward scanning search range in the pitch direction, determine the upper limit angle and lower limit angle data, as well as the upper limit position A and the lower limit position B;

[0009] Step 2: Set a deceleration section at the limit position so that the angular velocity of the pitch axis when it moves from the starting point of the deceleration section to the limit position is 0, and prevent the pitch axis from hitting the limit device;

[0010] Step 3: Set the deceleration factor K at different positions of the deceleration stage according to the electrical zero crossing point of the pitch axis angle;

[0011] Step 4: Set the angular velocity direction of the pitch axis so that the pitch axis does not decelerate when it is far away from the limit position;

[0012] Step 5: After the pitch axis enters the deceleration stage, the pitch axis motor angular velocity command is set to the product of the pitch axis motion angular velocity and the deceleration factor K.

[0013] Furthermore, in step 2, the electrical angle value at the position of the limit position at an angle of Δ1 on the side of the horizontal position C is the starting point of the deceleration section.

[0014] Furthermore, in step 3, the deceleration factor is based on It is calculated that the closer the current position of the pitch axis is to the limit position, the closer the deceleration factor K is to 0.

[0015] Furthermore, when the electrical zero-crossing point of the pitch axis angle is in different deceleration sections, the distance calculation from the current position of the pitch axis to the limit position is different, specifically:

[0016] When the electrical zero point of the pitch axis angle is in the deceleration section at the upper limit position A, if the current position P of the pitch axis is in the range of D to 360°, then the distance from the current position P of the pitch axis to the upper limit position A is 360°-P+A, where D=360°+A-Δ1; if the current position P of the pitch axis is in the range of 0° to A, then the distance from the current position P of the pitch axis to the upper limit position A is AP.

[0017] When the electrical zero point of the pitch axis angle is in the deceleration section at the lower limit position B, if the current position P of the pitch axis is in the range of 0° to E, the distance from the current position P of the pitch axis to the lower limit position B is 360°-P+B, where E=360°+B-Δ1; if the current position P of the pitch axis is in the range of B to 360°, the distance from the current position P of the pitch axis to the lower limit position B is BP.

[0018] Further, the angular velocity direction of the pitch axis moving from the lower limit position B to the upper limit position A is set to be positive, and the angular velocity direction of the upper limit position A moving to the lower limit position B is set to be negative.

[0019] The advantages of the present invention are:

[0020] 1. The electric turret pitch limit motion control method proposed in the present invention avoids the problem that the traditional photoelectric turret may rush through the limit position due to inertia when the speed is suddenly reduced from a high speed to 0. It adopts a uniform and gentle deceleration method that gradually decelerates from a high speed to 0, which is more suitable for the use requirements of the photoelectric turret and can better protect the limit device.

[0021] 2. The present invention also takes into account the angular electrical zero-crossing point unique to the pitch axis of the optoelectronic turret, and sets different deceleration factors according to the position of the angular electrical zero-crossing point to determine the deceleration speed of the pitch axis in the deceleration section. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The features and advantages of the present invention will become more readily understood through the following description with reference to the accompanying drawings, which are not drawn to scale and in which some features are exaggerated or minimized to show details of particular components:

[0023] Figure 1 is a structural exploded diagram of the optoelectronic turret in an embodiment of the present invention;

[0024] Figure 2 2 is a schematic diagram of the structure of the arc-shaped limit groove in an embodiment of the present invention;

[0025] Figure 3 is a schematic diagram of the connection relationship between the rotating component and the fixed component in an embodiment of the present invention;

[0026] Figure 4 is a schematic diagram of the relationship between the electrical zero-crossing point of the pitch axis angle and the current position of the pitch axis in an embodiment of the present invention;

[0027] Figure 5 It is a schematic diagram of various position angles of the photoelectric turret in an embodiment of the present invention.

[0028] In the figure: 1-azimuth assembly; 2-pitch frame; 3-pitch assembly; 31-rotating component; 32-fixed component; 33-limiting block; 4-sensor assembly. DETAILED DESCRIPTION

[0029] The present invention will be described in detail below with reference to the accompanying drawings by means of exemplary embodiments of the present invention. It should be noted that the following detailed description of the present invention is only for the purpose of illustration, and is not intended to limit the present invention.

[0030] A certain type of optoelectronic turret crane is installed on a UAV, which is required to have the ability to raise the horizontal position 20° upward, deflect 60° downward, and scan and search within a range of 80° in the pitch direction.

[0031] In this embodiment, the mechanical design of the limit device is first performed according to the pitch motion range specified in the above-mentioned photoelectric turret functional requirements.

[0032] like Figure 1 As shown, the optoelectronic turret includes an azimuth component 1, an elevation frame 2, a elevation component 3 and a sensor component 4, in which a visible light camera and an infrared thermal imager are installed.

[0033] like Figure 1 , 2 As shown, the pitch assembly 3 includes a rotating component 31 and a fixed component 32, which are rotatably connected via a set of angular contact bearings. The rotating component 31 is fixedly connected to the sensor assembly 4, and the fixed component 32 is fixedly connected to the outer wall of the pitch frame 2. With the pitch frame 2 as support, the rotating component 31 drives the sensor assembly 4 to achieve pitch axial rotation.

[0034] like Figure 2 As shown, the limiting device includes an arc-shaped limiting groove and a limiting block 33 designed inside the rotating component 31. The upper limit angle of the arc-shaped limiting groove is 20°, and the lower limit angle is 60°. The span of the arc-shaped limiting groove meets the requirements of the optoelectronic turret function to move within the pitch range of 80°. The limiting block 33 is a steel block. The limiting block 33 is provided with two through holes with a diameter of 4.2 mm and a rubber protective sleeve. There are two M4×8 threaded holes inside the fixed component 32. The limiting block 33 is fastened to the fixed component 32 by two M4×10 screws, as shown in FIG. Figure 3 shown.

[0035] When the optoelectronic turret's pitch axis rotates, the rotating component 31 can only rotate within the limited angle range of the limit groove under the constraint of the limit block 33. It will be blocked when it reaches the edge of the arc-shaped limit groove, thereby stopping the movement. The rubber sheath on the outer cover of the limit block 33 can reduce the impact force of the structural parts on the limit device when the software limit fails accidentally, thereby playing a role in protecting the structural parts.

[0036] The limited motion control method of the optoelectronic turret pitch assembly 3 comprises the following steps:

[0037] Step 1: Based on the horizontal position C set by the optoelectronic turret and the requirements for the up and down scanning search range in the pitch direction, determine the upper limit angle and lower limit angle data, as well as the upper limit position A and the lower limit position B.

[0038] like Figure 5 As shown, the electrical angle value of the horizontal position C is 343°. Since the upper limit angle is 20° and the lower limit angle is 60°, the electrical angle value of the upper limit position A is 3°, and the electrical angle value of the lower limit position B is 283°. The angle data change process when moving clockwise from the upper limit position A to the lower limit position B is: 3°→1°→0° / 360°→283°, and 0° / 360° is the electrical zero point of the pitch axis angle.

[0039] Step 2: Set a deceleration section at the limit position so that the angular velocity of the pitch axis when it moves from the starting point of the deceleration section to the limit position is 0, to prevent the pitch axis from colliding at the upper limit angle or lower limit angle of the arc-shaped limit groove and damaging the optoelectronic turret components.

[0040] The electrical angle value at the Δ1 angle on the side of the limit position close to the horizontal position C is the starting point of the deceleration section. Set Δ1 = 5°. Figure 5 As shown in the figure, the deceleration section of the upper limit position A is from 358° to 3°, and the electrical angle value of the starting point of the deceleration section is 358°. The deceleration section of the lower limit position B is from 288° to 283°, and the electrical angle value of the starting point of the deceleration section is 288°.

[0041] Step 3: Set the deceleration factor K at different positions of the deceleration stage according to the electrical zero crossing point of the pitch axis angle.

[0042] Deceleration factor based on It is calculated that the closer the current position of the pitch axis is to the limit position, the closer the deceleration factor K is to 0.

[0043] When the electrical zero point of the pitch axis angle is in different deceleration stages, the distance calculation from the current position of the pitch axis to the limit position is different, such as Figure 4 As shown, the calculation principle is as follows:

[0044] When the pitch axis angle electrical zero point (0° / 360°) is in the deceleration section at the upper limit position A, that is, the situation in this embodiment. If the current position P of the pitch axis is within the range of D (D=360°+A-Δ1) to 360°, as Figure 5 In the middle interval ①, the distance from the current position P of the pitch axis to the upper limit position A is 360°-P+A; if the current position P of the pitch axis is within the range of 0° to A, such as Figure 5 In the middle interval ②, the distance from the current position P of the pitch axis to the upper limit position A is AP.

[0045] In addition to the above situations, it is also possible that the electrical zero point (0° / 360°) of the pitch axis angle is in the deceleration section at the lower limit position B. In this case, the distance from the current position of the pitch axis to the limit position is calculated as follows: if the current position P of the pitch axis is in the range of 0° to E (E=360°+B-Δ1), then the distance from the current position P of the pitch axis to the lower limit position B is 360°-P+B; if the current position P of the pitch axis is in the range of B to 360°, then the distance from the current position P of the pitch axis to the lower limit position B is BP.

[0046] Step 4: Set the angular velocity direction of the pitch axis so that the pitch axis does not decelerate when it is away from the limit position. The angular velocity of the pitch axis is ω, and the angular velocity direction of the pitch axis moving from the lower limit position B to the upper limit position A is set to be positive, that is, ω>0, and the angular velocity direction of the pitch axis moving from the upper limit position A to the lower limit position B is set to be negative, that is, ω<0.

[0047] Through the above deceleration stage processing, when the pitch axis moves toward the limit position and reaches the limit position, the pitch axis angular velocity command is 0. At this time, if it needs to move in the opposite direction away from the limit position, the pitch axis will not be able to decelerate because the pitch axis angular velocity command is 0. By setting the positive and negative directions of the pitch axis movement angular velocity ω, the positive and negative values ​​of ω are used to determine whether it is close to the limit or away from the limit, and then in the deceleration stage processing, by superimposing the judgment of the positive and negative values ​​of the pitch axis movement angular velocity ω, the pitch axis can be unrestricted when moving away from the limit position.

[0048] Step 5: After the pitch axis enters the deceleration stage, the pitch axis motor angular velocity command ω0 is set to the product of the pitch axis motion angular velocity ω and the deceleration factor K, that is, ω0=ω×K.

[0049] The specific implementation of the above pitch axis speed design method in software is as follows:

[0050] like Figure 5 As shown in the figure, when the current position P of the pitch axis is within the range of 358°~360°(0°), that is, it is in the deceleration section of the upper limit position A, the distance between the current position P of the pitch axis and the upper limit position A is 3°+360°-P. The deceleration section at the upper limit position A is designed as follows in the software:

[0051] if((358°≤P≤360°)&(ω>0))

[0052]

[0053] ω0=ω×K

[0054] When the current position P of the pitch axis is within the range of 0°~3°(0°), the distance between the current position P of the pitch axis and the upper limit position A is 3°-P. The deceleration section at the upper limit position A is designed as follows in the software:

[0055] if((0°≤P≤3°)&(ω>0))

[0056]

[0057] ω0=ω×K

[0058] In the software, the deceleration section at the lower limit position B is designed as follows:

[0059] if((283°≤P≤288°)&(ω<0))

[0060]

[0061] ω0=ω×K

[0062] Through the above design, during the actual movement of the optoelectronic turret, it can be seen that the movement speed of the pitch axis gradually decreases when approaching the limit position, stops moving when reaching the limit position, and does not decelerate when moving away from the limit position in the opposite direction. It can leave the limit position freely, thus limiting the movement range of the pitch axis. At the same time, the transition of the entire movement is uniform and smooth.

[0063] Finally, it should be noted that the features mentioned and / or shown in the above description of the exemplary embodiments of the present invention may be combined in the same or similar manner into one or more other embodiments, combined with the features in other embodiments or substituted for the corresponding features in other implementations. The technical solutions obtained by these combinations or substitutions shall also be deemed to be included in the protection scope of the present invention.

Claims

1. A method for controlling the pitch limit motion of an optoelectronic turret, characterized in that: The following steps are involved: Step 1: Based on the horizontal position C set by the optoelectronic turret and the requirements for the upward and downward scanning search range in the pitch direction, determine the upper limit angle and lower limit angle data, as well as the upper limit position A and the lower limit position B; Step 2: Set a deceleration section at the limit position so that the angular velocity of the pitch axis when it moves from the starting point of the deceleration section to the limit position is 0, and prevent the pitch axis from hitting the limit device; Step 3: Set the deceleration factor K at different positions of the deceleration stage according to the electrical zero crossing point of the pitch axis angle; Step 4: Set the angular velocity direction of the pitch axis so that the pitch axis does not decelerate when it is far away from the limit position; Step 5: After the pitch axis enters the deceleration stage, set the pitch axis motor angular velocity command to the product of the pitch axis motion angular velocity and the deceleration factor K.

2. According to claim 1, a method for controlling the pitch limit motion of an optoelectronic turret is characterized in that: In step 2, the electrical angle value at the position of the limit position at an angle of Δ1 on the side of the horizontal position C is the starting point of the deceleration section.

3. According to claim 2, a method for controlling the pitch limit motion of an optoelectronic turret is characterized in that: In step 3, the deceleration factor is based on It is calculated that the closer the current position of the pitch axis is to the limit position, the closer the deceleration factor K is to 0.

4. The method for controlling the pitch limit motion of an optoelectronic turret according to claim 3, characterized in that: When the electrical zero point of the pitch axis angle is in different deceleration sections, the distance calculation from the current position of the pitch axis to the limit position is different, specifically: When the electrical zero point of the pitch axis angle is in the deceleration section at the upper limit position A, if the current position P of the pitch axis is in the range of D to 360°, the distance from the current position P of the pitch axis to the upper limit position A is 360°-P+A, where D=360°+A-Δ1; if the current position P of the pitch axis is in the range of 0° to A, the distance from the current position P of the pitch axis to the upper limit position A is AP; When the electrical zero point of the pitch axis angle is in the deceleration section at the lower limit position B, if the current position P of the pitch axis is within the range of 0° to E, the distance from the current position P of the pitch axis to the lower limit position B is 360°-P+B, where E=360°+B-Δ1; If the current position P of the pitch axis is within the range of B to 360°, the distance from the current position P of the pitch axis to the lower limit position B is BP.

5. The method for controlling the pitch limit motion of an optoelectronic turret according to claim 1, characterized in that: The angular velocity direction of the pitch axis moving from the lower limit position B to the upper limit position A is set to be positive, and the angular velocity direction of the upper limit position A moving to the lower limit position B is set to be negative.

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