Non-composite shaft photoelectric tracking mechanism and control method thereof

Abstract

The application discloses a non-composite shaft photoelectric tracking mechanism and a control method thereof, which comprises a quick mirror, a lens, a camera, a fiber collimator, a fixed fiber collimator device, a fixed camera device and a shell; the quick mirror and the fixed camera device are fixed on the rear plate of the shell; the lens and the camera are connected through a fixed pin; the camera and the fixed fiber collimator device are fixed on the fixed camera device; the shell is in a box body structure as a whole and plays a light shielding role; a cylindrical structure is arranged on the front plate of the shell in front of the reflecting mirror of the quick mirror, so that light can enter conveniently; the quick mirror, the camera and the lens constitute a beacon receiving light path; the receiving light path is reflected by the quick mirror and finally forms an image on the focal plane of a detector assembly. The mechanism has four working modes: a dormant mode, a capture mode, a sighting mode and an event-driven mode. The mechanism realizes accurate pointing control of a light beam with smaller volume, mass and lower energy consumption, realizes capture, aiming and tracking of a target, and is suitable for a microsatellite platform.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of beam control, and particularly relates to a non-composite-axis photoelectric tracking mechanism and a control method thereof. BACKGROUND

[0002] Two-dimensional precision pointing mechanisms have been widely applied in photoelectric tracking measurement, high-resolution imaging, laser optical communication and other fields. With the continuous improvement of application requirements, the pointing precision of the pointing mechanism is required to be higher and higher. At present, a composite-axis system (acquisition, tracking and pointing system, ATP system for short) is mainly composed of a two-dimensional coarse pointing mechanism (U-shaped frame / pendulum mirror) and a fast deflection mirror to achieve large-range and high-precision pointing. However, the structure of such a system is complex, and the volume and mass are large. With the development of unmanned aerial vehicles, floating platforms and satellite platforms, the ATP system is required to develop towards lowSWaP (small volume, light mass and low power consumption), and therefore, it is urgent to develop a non-composite-axis photoelectric tracking mechanism, i.e. to replace the traditional composite-axis system with one mechanism to achieve large-angle deflection while ensuring high-precision pointing.

[0003] Based on this, the present application proposes a non-composite-axis photoelectric tracking mechanism, which will help to solve the problem that the traditional composite-axis system cannot be applied to microsatellites due to its large volume and mass. SUMMARY

[0004] In order to solve the problems existing in the prior art, the purpose of the present application is to provide a non-composite-axis photoelectric tracking mechanism, which has the characteristics of compact structure, light mass, large stroke range, high precision and low power consumption.

[0005] To achieve the above purpose, the present application adopts the following technical solutions:

[0006] A non-composite axis photoelectric tracking mechanism includes: a quick-reflection mirror, a lens, a camera connected to the lens, a fiber collimator, a fixed fiber collimator device, a fixed camera device and a housing; the quick-reflection mirror is fixed to the rear plate of the housing, the reflector is tilted, and the mirror surface forms a 45° angle with the rear plate of the housing; the fixed camera device is fixed to the rear plate of the housing; the lens and the camera are connected by a fixing pin, and the lens is located directly below the quick-reflection mirror; the camera is fixedly installed on the fixed camera device; the fixed fiber collimator device is fixed to the fixed camera device by screws On top; the fiber collimator is fixed to the fixed fiber collimator device by screws; the shell 7 is a box body structure as a whole, which mainly plays a light-shielding role; the shell is composed of six plates including top, bottom, two sides, front and rear, and six mounting blocks, and the six plates are fixed into a box body by the mounting blocks; the bottom plate is provided with a hole for outputting the wires; the front plate is provided with a cylindrical structure just in front of the reflector of the quick reflex mirror to facilitate the entry of light; the beacon receiving light path is composed of the quick reflex mirror, the camera and the lens; the receiving light path enters the detector assembly after being reflected by the quick reflex mirror and finally forms an image on the focal plane.

[0007] Furthermore, the fast mirror comprises: a baffle, a reflector, a mirror seat, a piezoelectric stepping actuator, a butterfly-shaped flexible Hooke's hinge and a base; the baffle has two mounting holes and is connected to the mirror seat by screws; the baffle is L-shaped and does not contact the mirror surface of the reflector, and there is a gap between them, which mainly serves to prevent the reflector from falling and damaging the equipment below due to debonding during operation; the reflector is bonded to the mirror seat; the butterfly-shaped flexible Hooke's hinge is located in the center of the entire structure, and has threaded holes at the upper and lower ends, which are connected to the mirror seat and the base respectively by screws; the butterfly-shaped flexible Hooke's hinge The hinge has two rotational degrees of freedom and provides support for the reflector while serving as a kinematic pair. There are four piezoelectric stepping actuators, which are symmetrically and evenly distributed with the butterfly-shaped flexible Hooke's hinge as the center. The upper end is connected to the mirror holder by screws, and the lower end is fixedly connected to the base. The working surface of the base is at an angle of 45° to the mounting surface to ensure that the reflector can be placed at an angle, and the mirror surface is at a 45° angle to the back plate of the shell. The working surface of the base is provided with a hole for wire outlet; grooves for weight reduction are provided on both sides; the mounting surface is provided with mounting holes, and the base is fixed to the back plate of the shell by screws.

[0008] The working mode of the coarse-fine integrated two-dimensional precision pointing mechanism is as follows:

[0009] Working mode 1 (sleep mode): At this time, the mechanism is powered off and self-locked, and does not enter the power-on state;

[0010] Working mode two (capture mode): according to the ephemeris information, the angle difference with the target in the azimuth / elevation direction is obtained combined with the self attitude angle, and the specified signal is input to each piezoelectric stack of the four step piezoelectric actuators, so that the actuator moves in a peristaltic manner, and the motion accumulation (i.e. large stroke step mode) is carried out until the target enters the field of view;

[0011] Working mode three (aiming mode): when the target is in the field of view but not in the center of the field of view, the specified signal is input to each piezoelectric stack of the four step piezoelectric actuators, so that the fast mirror is deflected in a small range quickly and accurately (i.e. linear working mode), until the target moves to the center of the field of view;

[0012] Working mode four (event-driven mode): during the whole movement process, the two-dimensional pointing mechanism and the target are constantly shaking, when the target moves to the edge of the event-driven domain of the field of view (i.e. event-driven threshold), the fast mirror triggers the step mode, and steps further towards the target direction, so that the target enters the field of view domain, and then the mechanism enters the linear working mode until the target moves to the center of the field of view;

[0013] Compared with the prior art, the present application has the following advantages:

[0014] 1. The non-composite shaft photoelectric tracking mechanism provided by the present application has the characteristics of compact structure, light weight, large stroke range, high precision, low power consumption, etc., and is suitable for microsatellite platforms.

[0015] 2. The non-composite shaft photoelectric tracking mechanism provided by the present application can replace the traditional complex composite shaft system to realize accurate pointing control of the light beam with smaller volume, mass and lower energy consumption, and can realize capture, aiming and tracking of the target under the guidance of corresponding signals.

[0016] 3. The non-composite shaft photoelectric tracking mechanism provided by the present application uses a large number of flexible hinges as connecting moving parts, has the advantages of no friction and no gap, and increases the structural flexibility to reduce the influence of external environmental vibration on the reflector to a certain extent. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 It is a schematic diagram of the overall structure of the non-composite shaft photoelectric tracking mechanism of the present application;

[0018] Figure 2 It is a schematic diagram of the fast mirror structure of the present application;

[0019] Figure 3 It is a schematic diagram of the piezoelectric step actuator structure of the present application;

[0020] Figure 4 It is the principle of working mode two and the energization timing diagram of one cycle of extension of a step piezoelectric actuator in this mode,Figure 4 Fig. 2(a) is a schematic diagram of the principle of the working mode two, Figure 4 Fig. 2(b) is a power supply timing diagram of the elongation of a certain step-by-step piezoelectric actuator in the mode;

[0021] Figure 5 Fig. 3(a) is a schematic diagram of the principle of the working mode three, Figure 5 Fig. 3(a) is a schematic diagram of the principle of the working mode three, Figure 5 Fig. 3(b) is a power supply timing diagram of the elongation of a certain step-by-step piezoelectric actuator in the mode;

[0022] Figure 6 Fig. 4 is a schematic diagram of the principle of the working mode four. DETAILED DESCRIPTION

[0023] The application will be further described in detail below in combination with the drawings and specific examples.

[0024] As Figure 1 shown, a non-composite shaft photoelectric tracking mechanism comprises a fast mirror 1, a lens 2, a camera 3 connected with the lens 2, a fiber collimator 4, a fixed fiber collimator device 5, a fixed camera device 6 and a shell 7; the fast mirror 1 is fixed on the back plate of the shell 7, the reflecting mirror 1-2 is arranged obliquely, and the mirror surface forms a 45° angle with the back plate of the shell 7; the fixed camera device 6 is fixed on the back plate of the shell 7; the lens 2 and the camera 3 are connected through a fixed pin, and the lens 2 is located directly below the reflecting mirror 1-2 of the fast mirror 1; the camera 3 is fixedly installed on the fixed camera device 6; the fixed fiber collimator device 5 is fixed on the fixed camera device 6 through a screw; the fiber collimator 4 is fixed on the fixed fiber collimator device 5 through a screw; the shell 7 is a box body structure as a whole and mainly plays a light shielding role; the shell 7 is composed of a top plate, a bottom plate, two side plates, a front plate, a back plate and six mounting blocks, and the six plates are fixed into a box body through the mounting blocks; the bottom plate is provided with a hole for wire outlet; the front plate is provided with a cylindrical structure directly in front of the reflecting mirror 1-2 of the fast mirror 1, facilitating the entry of light; a beacon receiving light path is formed by the fast mirror 1, the camera 3 and the lens 2, and the beacon receiving light path enters the detector assembly after being reflected by the fast mirror 1 and finally forms an image on the focal plane.

[0025] As Figure 2As shown, the fast mirror 1 includes: a baffle 1-1, a reflector 1-2, a mirror base 1-3, a piezoelectric stepping actuator 1-4, a butterfly-shaped flexible Hooke's hinge 1-5 and a base 1-6; the baffle 1-1 has two mounting holes and is connected to the mirror base 1-3 by screws; the baffle 1-1 is L-shaped and does not contact the mirror surface of the reflector 1-2, and there is a gap between them, which mainly prevents the reflector 1-2 from falling and damaging the equipment below due to debonding during operation; the reflector 1-2 is bonded to the mirror base 1-3; the butterfly-shaped flexible Hooke's hinge 1-5 is located in the center of the entire structure, and has threaded holes at the upper and lower ends, which are connected to the mirror base 1-3 and the base 1-6 respectively by screws; the The butterfly-shaped flexible Hooke's hinge 1-5 has two rotational degrees of freedom and provides support for the reflector 1-2 while serving as a kinematic pair. There are four piezoelectric stepping actuators 1-4, which are symmetrically and evenly distributed with the butterfly-shaped flexible Hooke's hinge 1-5 as the center. The upper end is connected to the mirror holder 1-3 by screws, and the lower end is fixedly connected to the base 1-6. The working surface of the base 1-6 is at an angle of 45° to the mounting surface to ensure that the reflector 1-2 can be placed at an angle, and the mirror surface is at an angle of 45° to the back plate of the shell 7. The working surface of the base 1-6 is provided with a hole for outputting wires; grooves for reducing weight are provided on both sides; the mounting surface is provided with mounting holes, and the base 1-6 is fixed to the back plate of the shell 7 by screws.

[0026] like Figure 3 As shown, the piezoelectric stepping actuator 1-4 comprises: a base 1-4-1, a clamping mechanism 1-4-2, a driving mechanism 1-4-6, a clamping piezoelectric stack I 1-4-5, a clamping piezoelectric stack II 1-4-3 and a driving piezoelectric stack 1-4-4; the base 1-4-1 is fixedly connected to the fast mirror base 1-6 by a screw at the lower end, and is fixedly connected to one side of the clamping mechanism 1-4-2 at the upper end; the clamping mechanism 1-4-2 is formed by integrating the clamping mechanism I, the clamping mechanism II and a frame for connecting the two clamping mechanisms; a clamping piezoelectric stack, clamping piezoelectric stack I 1-4-5 and clamping piezoelectric stack II 1-4-3, is installed in each of the clamping mechanism I and the clamping mechanism II. In the original state, the two clamping mechanisms It is tightly pressed on the upper ends of the driving mechanism 1-4-6 to prevent the driving mechanism 1-4-6 from moving. The clamping piezoelectric stack I 1-4-5 and the clamping piezoelectric stack II 1-4-3 are extended after being energized, and the clamping mechanisms I and II are pushed upward to release the clamping state. At this time, the driving piezoelectric stack 2-4 is energized to extend (or shorten) and output displacement; there is a hollow rectangular structure at each end of the driving mechanism 1-4-6, and the two clamping piezoelectric stacks I and II are placed vertically therein, with a bridge-type flexible structure in the middle, and the driving piezoelectric stack 1-4-4 is installed in the middle of the bridge-type flexible structure; the upper end of the driving mechanism 1-4-6 is a Hooke's hinge; the upper end of the driving mechanism 1-4-6 has two mounting holes, which are fixed to the fast-reflecting mirror holder 1-3 by screws.

[0027] like Figures 4-6 As shown, the non-composite axis photoelectric tracking mechanism has the following working modes:

[0028] Working mode 1 (sleep mode): At this time, the mechanism is powered off and self-locked, and does not enter the power-on state;

[0029] Working mode 2 (capture mode): Based on the ephemeris information and combined with its own attitude angle, the angle difference with the target in the azimuth / pitch direction is obtained, and the specified signal is input to each piezoelectric stack of the four stepping piezoelectric actuators 1-4, so that the actuators 1-4 accumulate motion in a creeping manner (i.e., large-stroke stepping mode) until the target enters the field of view; taking one of the actuators moving upward as an example, in this mode, the actuator works as follows: Step 1, the clamping mechanism I is energized, the clamping piezoelectric stack I 1-4-5 gradually extends, the flexible clamping part is deformed by force, moves upward, leaves the driving mechanism 1-4-6, and releases the clamping state; Step 2, the driving mechanism 1-4-6 is energized, driving the piezoelectric stack 1-4-4 to extend, and moves a certain distance toward the clamping mechanism I. displacement; in the third step, the clamping mechanism I is powered off, the clamping piezoelectric stack I 1-4-5 is shortened, and the clamping state is restored; in the fourth step, the clamping mechanism II is powered on, the clamping piezoelectric stack II 1-4-3 is extended, the flexible clamping part is deformed by force, moves upward, and leaves the driving mechanism 1-4-6 to release the box position state; in the fifth step, the driving mechanism 1-4-6 is powered off, the driving piezoelectric stack 1-4-4 is shortened, and restored to the original state; in the sixth step, the clamping mechanism II is powered off, the clamping piezoelectric stack II 1-4-3 is shortened, and the clamping state is restored. The three piezoelectric stacks are restored to their original state, and the piezoelectric actuator completes a feeding motion and outputs a displacement S; by repeating the above steps, the piezoelectric stepping actuator can achieve a large-stroke displacement output through continuous feeding (when the actuator moves downward, its working method is the same);

[0030] Working mode three (aiming mode): When the target is within the field of view but not at the center of the field of view, the fast-reflecting mirror 1 is deflected quickly and precisely in a small range (i.e., linear working mode) by inputting a specified signal to each piezoelectric stack of the four stepping piezoelectric actuators 1-4 until the target moves to the center of the field of view; taking one of the actuators moving upward as an example, in this mode, the actuator works as follows: Step 1: The clamping mechanism I is energized, the clamping piezoelectric stack I 1-4-5 is extended, the flexible clamping part is deformed by force, moves upward, leaves the driving mechanism, and the clamping state is released; Step 2: The driving mechanism 1-4-6 is energized, and a linear driving signal is applied to drive the piezoelectric stack 1-4-4 for fine-tuning until the target is moved to the center of the field of view; Step 3: The clamping mechanism I is deenergized, the clamping piezoelectric stack I is shortened, and the clamping state is restored; Step 4: The clamping mechanism I is deenergized, the clamping piezoelectric stack I is shortened, and the clamping state is restored; Step 5: The clamping mechanism I is deenergized, the clamping piezoelectric stack I is shortened, and the clamping state is restored; Step 6: The clamping mechanism I is deenergized, the clamping piezoelectric stack I is shortened, and the clamping state is restored; Step 7: The clamping mechanism I is deenergized, the clamping piezoelectric stack I is shortened, and the clamping state is restored; Step 8: The clamping mechanism I is deenergized, the clamping piezoelectric stack I is shortened, and the clamping state is restored; Step 9: The clamping mechanism I is deenergized, the clamping piezoelectric stack I is shortened, and the clamping state is restored; Step 10: The clamping mechanism I is deenergized, the clamping

[0031] Working mode 4 (event-driven mode): Since the two-dimensional pointing mechanism and the target are constantly shaking during the entire movement process, when the target moves to the edge of the event-driven domain of the field of view (i.e., the event-driven threshold), the fast-reflection mirror 1 triggers the stepping mode and takes a step toward the target, bringing the target into the field of view. Subsequently, the mechanism enters the linear working mode until the target moves to the center of the field of view. The working method of its actuator can refer to working modes 2 and 3.

[0032] In a specific embodiment, there are four piezoelectric stepping actuators 1-4, which are symmetrically distributed in two groups, respectively controlling the rotational freedom of the fast mirror around the X axis and the Y axis, thereby achieving a large-stroke, high-precision deflection motion of the fast mirror.

Claims

1. A non-composite axis photoelectric tracking mechanism, characterized by: include: A quick reflex mirror (1), a lens (2), a camera (3) connected to the lens (2), a fiber collimator (4), a fixed fiber collimator device (5), a fixed camera device (6) and a housing (7); the quick reflex mirror (1) is fixed on the rear plate of the housing (7), the reflector (1-2) is tilted, and the mirror surface and the rear plate of the housing (7) form an angle of 45 degrees; the fixed camera device (6) is fixed on the rear plate of the housing (7); the lens (2) and the camera (3) are connected by a fixing pin, and the lens (2) is located directly below the reflector (1-2) of the quick reflex mirror (1); the camera (3) is fixedly mounted on the fixed camera device (6) The fixed optical fiber collimator (5) is fixed to the fixed camera device (6) by screws; the optical fiber collimator (4) is fixed to the fixed optical fiber collimator (5) by screws; the housing (7) is a box structure as a whole, mainly serving as a light shielding device; the housing (7) is composed of six plates, namely, a top, a bottom, two side surfaces, a front and a rear, and six mounting blocks, and the six plates are fixed into a box body by the mounting blocks; the bottom plate is provided with a hole for outputting the wire; the front plate is provided with a cylindrical structure in front of the reflector (1-2) of the quick-reflector (1) to facilitate the entry of light; the quick-reflector (1), the camera (3) and the lens (2) constitute a beacon receiving optical path; The receiving light path is reflected by a quick-reflection mirror (1) and then enters a detector assembly to form an image on a focal plane. The quick-reflection mirror (1) comprises a baffle (1-1), a reflector (1-2), a mirror base (1-3), a piezoelectric stepping actuator (1-4), a butterfly-shaped flexible Hooke's hinge (1-5) and a base (1-6).

2. The non-composite axis photoelectric tracking mechanism according to claim 1, characterized in that: The baffle (1-1) has two mounting holes and is connected to the mirror base (1-3) by screws; the baffle (1) is L-shaped and does not contact the mirror surface of the reflector (1-2), with a gap between them, which mainly serves to prevent the reflector (1-2) from falling and damaging the equipment below due to debonding during operation; the reflector (1-2) is bonded to the mirror base (1-3); the butterfly-shaped flexible Hooke's hinge (1-5) is located in the center of the entire structure, and has threaded holes at both the upper and lower ends, which are respectively connected to the mirror base (1-3) and the base (1-6) by screws; the butterfly-shaped flexible Hooke's hinge (1-5) has two rotational degrees of freedom, and while serving as a kinematic pair, it also controls the rotation of the mirror base (1-3) and the base (1-6). The reflector (1-2) provides support force; there are four piezoelectric stepping actuators (1-4), which are symmetrically and evenly distributed with the butterfly-shaped flexible Hooke hinge (1-5) as the center, and the upper ends are connected to the mirror seat (1-3) by screws, and the lower ends are fixedly connected to the base (1-6); the working surface of the base (1-6) and the mounting surface are at an angle of 45 degrees to ensure that the reflector (1-2) can be placed at an angle, and the mirror surface and the back plate of the shell (7) are at an angle of 45 degrees; the working surface of the base (1-6) is provided with a hole for outputting wires; grooves for reducing weight are provided on both sides; the mounting surface is provided with mounting holes, and the base (1-6) is fixed to the back plate of the shell (7) by screws.

3. A control method for a non-composite axis photoelectric tracking mechanism, based on the non-composite axis photoelectric tracking mechanism according to claim 1, characterized in that: The mechanism adopts a hybrid drive mode, with the following four working modes: Working mode 1: Sleep mode, at this time the mechanism is powered off and self-locked, and does not enter the power-on state; Working mode 2: Capture mode, based on the ephemeris information and the attitude angle of the target, the angle difference in azimuth / pitch direction is obtained. By inputting a specified signal to each piezoelectric stack of the four stepping piezoelectric actuators (1-4), the actuators (1-4) are made to perform motion accumulation in a large-stroke stepping mode in a creeping manner until the target enters the field of view; Working mode three: aiming mode, when the target is within the field of view but not in the center of the field of view, by inputting a specified signal to each piezoelectric stack of the four stepping piezoelectric actuators (1-4), the fast mirror (1) is deflected in a small range, fast and high-precision, i.e., linear working mode, until the target moves to the center of the field of view; Working mode 4: Event-driven mode. Since the mechanism and the target are constantly shaking during the entire movement process, when the target moves to the edge of the event-driven domain of the field of view, that is, the event-driven threshold, the fast mirror (1) triggers the stepping mode and takes a step toward the target, so that the target enters the field of view. Subsequently, the mechanism enters the linear working mode until the target moves to the center of the field of view.

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