Dynamic self-adaptive anti-backlash continuous zoom lens device and zoom method

Abstract

The invention discloses a dynamic self-adaptive anti-backlash continuous zoom lens device and a zoom method. The device comprises a zoom lens group, a compensation lens group and a focusing lens group, the zoom lens group is used for changing the interval between the lenses by moving along the optical axis so as to change the focal length of the device; the compensating lens group is used for performing micro movement along the optical axis relative to the zoom lens group to compensate image plane defocus caused by movement of the zoom lens group; and the focusing lens group moves along the optical axis in the fixed lens cone and is used for finely adjusting the focal length. According to the invention, the sliding rail and the constant-force spring cooperate for guiding to improve the rigidity, so that the zooming process can be smooth and stable in impact and vibration environments; by applying a constant pre-tightening force to each moving part, various mechanical gaps can be dynamically, adaptively, synergistically and effectively eliminated, the smooth movement of the mechanism is ensured, the shaking or blurring phenomenon of an image in the zooming process is avoided, and the definition and stability of the image are ensured.

Description

Technical Field

[0001] This invention belongs to the field of infrared technology, and more specifically, relates to a dynamic adaptive gap elimination continuous zoom lens device and zoom method. Background Technology

[0002] Infrared continuous zoom technology utilizes the difference in infrared radiation characteristics between a target and its background to detect and identify targets. Due to the extremely strong penetrating power of the infrared spectrum, infrared zoom systems can operate in harsh environments such as smoke and dust, and are therefore widely used in ground equipment, airborne pods, rocket-borne camera devices, and unmanned aerial vehicle systems. The system changes the focal length by altering the spacing between lens groups, allowing for continuous focal length changes within a certain range while maintaining a fixed image plane position. It uses a short focal length and a large field of view to search for targets, and then performs high-precision tracking of the target using a long focal length and a small field of view through continuous zoom.

[0003] Currently, infrared continuous zoom devices mainly utilize mechanical compensation structures, with the lens movement driven primarily by lead screw guide mechanisms and cam-type zoom mechanisms. Among these, cam-type zoom mechanisms are receiving increasing attention due to their unique advantages, as a single motor driving the cam can simultaneously move multiple lenses to pre-set positions, achieving continuous zoom. However, in existing cam-based continuous zoom devices, mechanical backlash is a key factor affecting system performance.

[0004] The gap between the cam guide pin and the cam guide groove is the most critical fit clearance in the zoom device. On the one hand, the machining error of the cam groove and the diameter tolerance of the guide pin work together to form this gap. On the other hand, the contact surfaces of the cam groove and the guide pin will rub against each other continuously, causing fatigue wear and material shedding, which further widens the initial fit clearance. This process is dynamic and cyclically cumulative. After long-term use, the gap continues to widen, and the cam guide pin will experience radial wobble within the groove, resulting in angular deviation of the lens assembly displacement.

[0005] The gap between the guide pin and the cam guide groove can also cause the guide pin to jump between the two surfaces when the cam rotates in different directions, resulting in an unstable zooming process and, in severe cases, image jitter.

[0006] In addition, in order to ensure smooth movement of the zoom mechanism, clearance fit is used between the lens frame and the lens barrel, and between the lens barrel and the cage. The device has low rigidity, and the clearance changes dynamically under impact, vibration and other environments. This changes the state of the moving parts and causes instability in the zoom movement. It is very likely to cause the zoom mechanism to move unevenly, resulting in poor image quality or even shaking.

[0007] Therefore, it is crucial to develop an infrared continuous zoom device that can adapt to multiple wavelength spectra, has a compact structure, high rigidity, stable performance under impact and vibration environments, can adaptively and continuously eliminate mating gaps, return gaps, and continuously expanding wear gaps on contact surfaces, ensuring smooth and stable zooming, and is easy to implement in low-cost engineering applications. Summary of the Invention

[0008] To address the shortcomings of existing technologies, the present invention aims to provide a dynamic adaptive gap-eliminating continuous zoom lens device. This device addresses the problems in existing cam-type zoom mechanisms, such as various movement gaps including fit gaps, return gaps, and continuously expanding wear gaps on contact surfaces. These problems lead to unstable zoom mechanism movement under impact and vibration, easy jumping and jamming during zooming, difficulty in consistently maintaining clear image quality, and image shaking.

[0009] To achieve the above objectives, in one aspect, the present invention provides a dynamically adaptive backlash-eliminating continuous zoom lens device, comprising:

[0010] The zoom lens assembly consists of a zoom lens, an inner zoom lens frame, a zoom lens assembly spacer, and an outer zoom lens frame connected in sequence. The zoom lens assembly changes the spacing between lenses by moving along the optical axis, thereby altering the focal length of the device. The zoom lens collects and focuses infrared radiation entering the zoom lens assembly. The inner zoom lens frame securely mounts the zoom lens. The zoom lens assembly spacer adjusts the mounting distance between the inner and outer zoom lens frames, ensuring the actual lens position is as close as possible to the theoretical position. The outer zoom lens frame houses the zoom lens assembly within the fixed lens barrel, providing support and guidance during its movement.

[0011] Compensation lens group: The compensation lens group consists of compensation lens A, compensation lens group spacer, compensation lens B, and compensation lens frame; the compensation lens group is used to compensate for image defocus caused by the movement of the zoom lens group by making a slight movement relative to the zoom lens group along the optical axis; compensation lens A and compensation lens B move simultaneously at equal intervals to collect and converge infrared light from the zoom lens; the compensation lens group spacer is used to install compensation lens A; the compensation lens frame is used to install the compensation lens group in the fixed lens barrel and plays a supporting and guiding role during the movement of the compensation lens group;

[0012] Focusing lens assembly: This assembly consists of an inner focusing lens frame, a focusing lens, and an outer focusing lens frame. The focusing lens assembly moves along the optical axis within the fixed lens barrel based on factors such as zoom distance and ambient temperature, thereby fine-tuning the focus and achieving a clear image. The inner focusing lens frame mounts the focusing lens and is inverted and installed within the outer focusing lens frame. The outer focusing lens frame houses the focusing lens assembly within the fixed lens barrel and provides support and guidance during its movement.

[0013] Preferably, the dynamic adaptive backlash elimination continuous zoom lens device further includes a fixed lens frame, a focusing cam, a fixed lens barrel, a washer A, a zoom cam, a washer B, a base, a cam guide pin, and a cylindrical roller bearing.

[0014] The fixed lens frame is used to fix the fixed lens barrel and focusing cam to the base; the focusing cam and zoom cam are used to drive the focusing lens group, zoom lens group, and compensating lens group to move linearly in the fixed lens barrel through symmetrically distributed cam guide pins, thereby changing the focal length; the inner wall of the fixed lens barrel is used to install the zoom lens group, compensating lens group, and focusing lens group, and the outer wall is used to install the zoom cam and focusing cam. Six linear guide grooves are symmetrically distributed along the circumference to limit the movement of the cam guide; washer A is used to isolate the zoom cam and focusing cam to avoid interference between their movements, and is also used to adjust the installation interval; the zoom cam rotates itself under the drive of the zoom motor, used for The cam guide moves, which in turn drives the zoom lens assembly and the compensating lens assembly to move along a predetermined path to complete the focal length change; washer B is used to adjust the mounting position of the zoom cam; the base is used to support and mount the entire infrared continuous zoom system based on a cylindrical cam mechanism; the cylindrical roller bearing is mounted on the cam guide pin, and the high rigidity of the bearing helps to suppress the radial runout of the camshaft, and its line contact structure can effectively disperse contact stress, which is crucial to ensuring the displacement transmission accuracy of the cam curve. Driven by the zoom cam and the focusing cam, the cam guide pin drives the zoom lens assembly, the compensating lens assembly, and the focusing lens assembly to move along a predetermined path to complete the zoom action.

[0015] Preferably, the dynamic adaptive backlash elimination continuous zoom lens device further includes a focusing motor bracket, a focusing gear, a focusing motor, a zoom motor bracket, a zoom gear, and a zoom motor; the focusing motor bracket and the zoom motor bracket are used to connect the focusing motor and the zoom motor to the fixed lens frame; the focusing gear and the zoom gear are used to mesh with racks distributed on the focusing cam and the zoom cam, driving the two cams to rotate;

[0016] Preferably, the dynamic adaptive gap-eliminating continuous zoom lens device further includes a constant force magnetic spring composed of a constant force magnetic spring stator, a constant force magnetic spring mover, and a magnetic spring connecting seat; the constant force magnetic spring forms a stable preload through the air gap magnetic field between the permanent magnet and the iron ring assembly, and is connected to the cam guide pin through the magnetic spring connecting seat to establish a continuous and reliable contact pressure, fundamentally eliminating fit gaps, return gaps, and continuously expanding wear gaps on the contact surface. When the guide pin moves with the cam groove and generates axial displacement, the tension of the magnetic spring remains constant, ensuring consistent gap control effect throughout the entire zoom range.

[0017] Preferably, the zoom lens group, compensating lens group, focusing lens group and fixed lens barrel are designed with symmetrically arranged sliding guide rail structure, which, together with symmetrically arranged high rigidity constant force magnetic springs, form a high rigidity motion system, which can ensure sufficient stability under impact and vibration environment, and the zooming process is not affected by the existence of gaps.

[0018] In summary, the technical solutions conceived by this invention have the following beneficial effects compared with the prior art:

[0019] (1) The infrared continuous zoom lens device can achieve a compact design. The focusing lens group slide rail and constant force spring work together to guide and improve rigidity, so that the zooming process can be smooth and stable under impact and vibration.

[0020] (2) It can apply constant preload to each moving part, and can dynamically and adaptively eliminate various mechanical gaps, ensure smooth movement of the mechanism, avoid image jitter or blurring during zooming, and ensure image clarity and stability.

[0021] (3) The device has high rigidity and fast response speed, enabling rapid and high-precision focal length adjustment, thereby achieving continuous zoom of the infrared imaging system and ensuring imaging quality and clarity. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the internal structure of the continuous zoom lens device and zoom method involving dynamic adaptive gap elimination provided in the embodiments of the present invention.

[0023] Figure 2 , Figure 3 This is a schematic diagram of the external structure of the continuous zoom lens device and zoom method involving dynamic adaptive gap elimination provided in an embodiment of the present invention.

[0024] Figure 4 This is a schematic diagram of the variable magnification cam structure provided in an embodiment of the present invention;

[0025] Figure 5 This is a schematic diagram of the focusing cam structure provided in an embodiment of the present invention;

[0026] Figure 6 This is a schematic diagram of the fixed lens barrel structure provided in an embodiment of the present invention;

[0027] Figure 7 This is a schematic diagram of the zoom lens outer frame structure provided in an embodiment of the present invention;

[0028] Figure 8 This is a schematic diagram of the compensation frame structure provided in an embodiment of the present invention;

[0029] Figure 9 This is a schematic diagram of the focusing lens frame structure provided in an embodiment of the present invention;

[0030] Figure 10 This is a schematic diagram of the continuous zoom process of the cam system provided in an embodiment of the present invention;

[0031] Figure 11 This is the correspondence between control sequence points and focal length provided in the embodiments of the present invention.

[0032] Figure 12 This is the correspondence between control sequence points and variable magnification cam rotation angles provided in the embodiments of the present invention.

[0033] Figure 13 This is the correspondence between the control sequence points and the focusing cam rotation angle provided in the embodiments of the present invention.

[0034] Figure 14 The motion curves of the zoom lens and compensating lens group provided in the embodiments of the present invention are

[0035] Figure 15 This is the focusing lens motion curve provided in the embodiment of the present invention.

[0036] In all the accompanying drawings, the same reference numerals are used to denote the same elements or structures, including: 1. Zoom lens; 2. Zoom lens inner frame; 3. Zoom lens group spacer; 4. Zoom lens outer frame; 5. Compensating lens A; 6. Compensating lens group spacer; 7. Compensating lens B; 8. Compensating lens frame; 9. Focusing lens inner frame; 10. Focusing lens; 11. Focusing lens outer frame; 12. Fixed lens frame; 13. Focusing cam; 14. Fixed lens barrel; 15. Washer A; 16. Zooming cam; 17. Washer B; 18. Base; 19. Cam guide pin; 20. Cylindrical roller bearing; 21. Constant force magnetic spring stator; 22. Constant force magnetic spring mover; 23. Constant force magnetic spring connecting seat; 24. Focusing motor bracket; 25. Focusing gear; 26. Focusing motor; 27. Zoom motor bracket; 28. Zoom gear; 29. Variable magnification motor; 30. Focusing lens slide rail. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0038] A dynamic adaptive backlash-eliminating continuous zoom lens device comprises: First, a symmetrically arranged sliding guide structure for the zoom lens group, compensating lens group, focusing lens group, and fixed lens barrel, combined with symmetrically arranged high-rigidity constant-force magnetic springs, forming a high-rigidity motion system that ensures sufficient stability under impact and vibration, and the zooming process is unaffected by gaps. Second, the constant-force magnetic springs generate a stable preload through the air gap magnetic field between the mover and stator, establishing continuous and reliable contact pressure in the motion pairs formed by the rolling bearing and the cam and guide pin, the guide pin and the cam, and the moving lens group and the fixed lens barrel, fundamentally eliminating mechanical backlash. Furthermore, its constant force output throughout its stroke ensures consistent gap control across the entire zoom range. Finally, a control signal is calculated based on the focal length value of the current field of view and the position value from optical simulation. This control signal drives the zoom cam to move, and through the cam guide pin, the zoom lens group and compensating lens group move linearly to their theoretical positions within a cam curve groove that satisfies a functional relationship. Then, through a similar focusing process, the gap between the lenses and the focal length of the device change according to the set values, resulting in clear and stable imaging.

[0039] A dynamic adaptive backlash-free continuous zoom lens device includes: a zoom lens, an inner frame of the zoom lens, a zoom lens group spacer, an outer frame of the zoom lens, a compensation lens, a compensation lens group spacer, a compensation lens B, a compensation lens frame, an inner frame of the focusing lens, a focusing lens, an outer frame of the focusing lens, a fixed lens frame, a focusing cam, a fixed lens barrel, a washer A, a zoom cam, a washer B, a base, a cam guide pin, a cylindrical roller bearing, a constant force magnetic spring stator, a constant force magnetic spring mover, a constant force magnetic spring connecting seat, a focusing motor bracket, a focusing gear, a focusing motor, a zoom motor bracket, a zoom gear, a zoom motor, and a focusing lens group slide rail.

[0040] Example

[0041] like Figure 1 , Figure 2 and Figure 3 As shown, the present invention provides a high-precision infrared continuous zoom lens device with adaptive backlash elimination, comprising:

[0042] The zoom lens 1 is installed in the inner frame 2 of the zoom lens, and then the whole assembly is installed in the outer frame 4 of the zoom lens, and then coaxially installed in the fixed lens barrel 14. The zoom lens assembly spacer 3 ensures the precise optical position of the zoom lens 1, ensuring that infrared light is converged and transmitted through the zoom lens 1 according to the preset path.

[0043] Compensating lens A5 is connected to compensating lens B7 from the back via a compensating lens group spacer and is installed inside compensating lens frame 8. Compensating lens frame 8 is coaxially installed inside fixed lens barrel 14. The two compensating lenses connected from the back move simultaneously at equal intervals inside fixed lens barrel 14 and work together to collect and converge infrared light from zoom lens 1.

[0044] The focusing lens 10 is mounted on the inner frame 9 of the focusing lens by means of a flat surface. Then, the inner frame 9 of the focusing lens is mounted on the outer frame 11 of the focusing lens by adhesive. It has good surface accuracy and is coaxially mounted in the fixed lens barrel 14. It moves linearly in the fixed lens barrel 14 to fine adjust the focal length.

[0045] The structures of the zoom lens outer frame 4, the compensation lens frame 8, and the focusing lens outer frame 11 are as follows: Figure 4 , Figure 5 and Figure 6 As shown, the outer walls of the zoom lens frame 4 and the compensation lens frame 8 are designed with four symmetrically arranged sliders, which, together with the inner cavity of the fixed lens barrel 14, form a sliding guide. The focusing lens frame 11 and the four evenly distributed focusing lens group slide rails 30 form a sliding guide. During the zooming process, the several frames (zoom lens frame 4, compensation lens frame 8, and focusing lens frame 11) need to withstand multi-directional loads such as the driving force transmitted by the cam, the gravity of the lens group, and the preload of the constant force magnetic spring. This double symmetrical support structure achieves symmetrical balance of the force system, and the interlacing of the frames avoids interference during the movement process. The symmetrical slide rails, constant force magnetic springs, and cylindrical roller bearings form a complementary and synergistic precision transmission system. The symmetrical constraint of the slide rails ensures that the preload of the magnetic spring is evenly distributed on the cam groove contact surface, avoiding local wear caused by unilateral force and stably controlling the fit clearance between the guide pin and the cam groove. While achieving greater device stiffness under the preload of the constant force magnetic spring, the symmetrical slide rail ensures that the constant force characteristic of the magnetic spring is fully utilized, and the image plane drift is greatly reduced throughout the entire stroke.

[0046] The structure of the fixed lens tube 14 is as follows Figure 7 As shown, the focusing, zoom, and compensation linear guide grooves are symmetrically distributed around the fixed lens barrel 14. One side has six evenly distributed threaded holes, which are used to connect and install the lens to the right side of the fixed lens frame 12 via screws. The other side is connected to the base 18 via the bottom surface.

[0047] The focusing cam 13, washer A15, zoom cam 16, and washer B17 are sequentially installed on the outer circumference of the fixed lens barrel 14. The focusing cam 13 is as follows: Figure 8 As shown, the two sets of variable magnification curve grooves and compensation curve grooves are symmetrically distributed along the circumference, and a gear rack is also distributed along the circumference. The structure of the variable magnification cam 16 is as follows: Figure 9 As shown, the principle of the focusing cam 13 is similar. Washer A15 is installed between the two cams, and washer B17 is installed between the focusing cam 13 and the fixed lens barrel 14. The two H68 copper washers with self-lubricating effect are selected with appropriate thickness, and together with the action of the constant force magnetic spring, the axial clearance of the cam is controlled, so as to ensure that the cam can rotate easily and have good motion accuracy.

[0048] The base 18 is installed at the bottom of the assembly and connects with the fixed lens frame 12 and fixed lens barrel 14 to support the entire assembly. The cam guide pin 19 is installed in the curved guide groove and mates with the cylindrical roller bearing 20. Its upper end is connected to the constant force magnetic spring connecting seat 23 by a thread. The constant force magnetic spring consists of a constant force magnetic spring stator 21 and a constant force magnetic spring mover 22. The constant force magnetic spring connecting seat is installed on the constant force magnetic spring mover 22.

[0049] One end of the focusing motor bracket 24 is mounted on the fixed lens frame 12, and the other end is mounted on the focusing motor 26. The focusing gear 25 is mounted on the motor shaft. Similarly, the zoom motor bracket 28, zoom gear 29, and zoom motor 30 are sequentially mounted on the fixed lens barrel 14. The two motors drive the two sets of cams to achieve the zoom function according to servo commands.

[0050] like Figure 10 As shown, this embodiment also provides a zoom method for a dynamically adaptive gap-eliminating continuous zoom lens device, including the following steps:

[0051] The first step involves a symmetrically arranged sliding guide structure for the zoom lens group, compensating lens group, focusing lens group, and fixed lens barrel. This, combined with symmetrically arranged high-rigidity constant-force magnetic springs for pre-tensioning, forms a high-rigidity motion system that ensures sufficient stability under impact and vibration conditions, and prevents the zooming process from being affected by gaps.

[0052] The second step involves the constant force magnetic spring generating a stable preload through the air gap magnetic field between the mover and the stator, establishing a continuous and reliable contact pressure in the kinematic pairs formed by the rolling bearing and the cam and the guide pin, the guide pin and the cam, and the moving mirror assembly and the fixed mirror barrel, thereby fundamentally eliminating mechanical clearance.

[0053] The third step is to ensure that the constant force magnetic spring maintains a constant force output throughout the entire zoom range of the device, eliminating various mechanical gaps and ensuring consistent gap control effect throughout the zoom range.

[0054] The fourth step involves obtaining the focal length value and its corresponding control step size, rotation angle relationship, and start and end position parameters for the two cams. Based on the focal length setting of the current field of view and the position data obtained from optical simulation, the precise positions of the zoom lens assembly and the compensation lens assembly are determined. Subsequently, this position information is converted into servo control commands for the zoom motor and the compensation motor.

[0055] Fifth, the variable-magnification motor and the compensation motor operate in the specified direction and speed according to these signals.

[0056] In the sixth step, the gears connected to the two motor shafts mesh with the racks distributed on the focusing cam and the zoom cam, respectively. The power of these motors is transmitted to the zoom cam and the compensation cam, driving them to rotate.

[0057] The correspondence between control sequence points and focal length values ​​is as follows: Figure 11 The relationship between the control sequence points and the rotation angle of the variable magnification cam is shown in the figure. Figure 12 As shown, the correspondence between the control sequence points and the focusing cam rotation angle is as follows: Figure 13 As shown.

[0058] Step 7: Guided by the cam guide pin, the zoom lens assembly and the compensating lens assembly move along a cam curve groove that satisfies a specific functional relationship. The correspondence between this motion relationship and the control points is as follows: Figure 14 As shown. Finally, these components move in a straight line along the optical axis to the position set in the simulation until the entire zoom process is successfully completed.

[0059] The eighth step is to observe the image effect after zooming, calculate the gradient change of the image grayscale value based on the video frame content, and then determine the deviation between the actual focal length and the theoretical focal length, thereby generating a focal length adjustment command.

[0060] Step 9: Based on the focusing drive signal, the focusing cam rotates, ultimately driving the focusing lens to move precisely to the preset target position. The correspondence between the focusing lens and the control sequence points is as follows: Figure 15 As shown, this enables adaptive elimination of various gaps, rapid and high-precision focus adjustment, and continuous zooming of the infrared imaging system.

[0061] In summary, compared with the prior art, the present invention has the following advantages:

[0062] The dynamic adaptive gap-eliminating continuous zoom lens device provided by this invention can achieve a high-rigidity motion system with stable gap control, ensuring sufficient stability under impact and vibration environments, and the zoom process is not affected by the environment.

[0063] The present invention provides a dynamic adaptive backlash elimination continuous zoom lens device in which a constant force magnetic spring forms a stable preload through the air gap magnetic field between the mover and the stator, and establishes a continuous and reliable contact pressure in the kinematic pairs formed by the rolling bearing and the cam and the guide pin, the guide pin and the cam, and the moving lens group and the fixed lens barrel, thereby fundamentally eliminating mechanical backlash.

[0064] The dynamic adaptive gap elimination continuous zoom lens device provided by the present invention has a constant preload output throughout the entire stroke, and the gap control effect is consistent throughout the entire zoom range. It can effectively overcome the impact of the dynamic gap increase of the friction between the guide pin and the cam guide groove on the system performance, and effectively suppress the phenomenon of unstable zoom process and image shaking caused by the guide pin jumping between the two contact surfaces when the cam changes direction and rotates.

[0065] The cylindrical cam mechanism of this invention, with its ability to quickly respond to control signals, can achieve high-precision focal length adjustment, thereby realizing the continuous zoom function of the infrared imaging system and ensuring the optimization of image quality and clarity.

[0066] During zooming, this invention demonstrates the ability to respond quickly to control signals, achieving smooth and stable high-precision focus adjustment. It effectively suppresses potential image jitter or blurring, ensuring high image clarity and stability.

[0067] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A dynamic self-adapting gap-closing continuous zoom lens device, characterized in that, It includes: Variable magnification lens group: sequentially connected by variable magnification lens (1), variable magnification lens inner frame (2), variable magnification lens group spacer (3) and variable magnification lens outer frame (4); the variable magnification lens group is used for changing the interval between lenses by moving along the optical axis, so as to change the focal length of the device; the variable magnification lens (1) is used for collecting and converging the infrared radiation entering the variable focal length lens device; the variable magnification lens inner frame (2) is used for mounting the variable magnification lens (1); the variable magnification lens group spacer (3) is used for adjusting the distance between the variable magnification lens inner frame (2) and the variable magnification lens outer frame (4); the variable magnification lens outer frame (4) is used for mounting the variable magnification lens group in the fixed lens barrel; Compensation lens group: composed of compensation lens A (5), compensation lens group spacer (6), compensation lens B (7) and compensation lens frame (8); the compensation lens group is used for moving along the optical axis to compensate the image plane defocus caused by the movement of the variable magnification lens group; compensation lens A (5) and compensation lens B (7) move simultaneously and equally spaced, which are used for collecting and converging light from the variable magnification lens; the compensation lens group spacer (6) is used for mounting the compensation lens A (5); the compensation lens frame (8) is used for mounting the compensation lens group in the fixed lens barrel; Focusing lens group: composed of focusing lens inner frame (9), focusing lens (10) and focusing lens outer frame (11); the focusing lens group moves along the optical axis in the fixed lens barrel, which is used for fine tuning the focal length; the focusing lens inner frame (9) is used for mounting the focusing lens (10) and is mounted in the focusing lens outer frame (11) in reverse; the focusing lens outer frame (11) is used for mounting the focusing lens group in the fixed lens barrel; Focusing cam (13), variable magnification cam (16) and cam guide pin (19): the focusing cam (13) and variable magnification cam (16) are used for driving the focusing lens group and the variable magnification lens group, compensation lens group to move linearly in the fixed lens barrel respectively through the symmetrically arranged cam guide pin (19), so as to realize the change of focal length; the variable magnification cam (16) rotates itself under the drive of the variable magnification motor, which is used for driving the cam guide pin (19) to move, and then drives the variable magnification lens group and the compensation lens group to move along the specified path, so as to complete the change of focal length; Constant force magnetic spring: composed of constant force magnetic spring stator (21), constant force magnetic spring rotor (22) and magnetic spring connecting seat (23); the constant force magnetic spring forms a stable pre-tightening force through the air gap magnetic field between the permanent magnet and the iron ring assembly, and is connected with the cam guide pin (19) through the magnetic spring connecting seat (23), so as to establish a continuous and reliable contact pressure and eliminate the mechanical gap; when the cam guide pin (19) moves along the cam groove and produces axial displacement, the tension of the constant force magnetic spring remains constant, which ensures that the gap control remains consistent in the entire zoom range.

2. The dynamically self-adapting backlash-free continuous zoom lens apparatus according to claim 1, wherein, It also includes fixed lens frame (12), focusing cam (13), fixed lens barrel (14), variable magnification cam (16), base (18) and cam guide pin (19); The fixed lens frame (12) is used for fixing the fixed lens barrel (14) and the focusing cam (13) on the base (18); The inner wall of the fixed lens barrel (14) is used for mounting the variable magnification lens group, the compensation lens group and the focusing lens group, and the outer wall is used for mounting the variable magnification cam (16) and the focusing cam (13).

3. The dynamically self-adapting backlash-free continuous zoom lens apparatus according to claim 1, wherein, Further comprising washer A (15) and washer B (17); The washer A (15) is used to isolate the zoom cam (16) and the focusing cam (13) to avoid the movement interference, and is used to adjust the installation interval; The washer B (17) is used to adjust the installation position of the zoom cam (16).

4. The dynamically self-adapting backlash-free continuous zoom lens apparatus according to claim 2, wherein, Further comprising cylindrical roller bearing (20); The cylindrical roller bearing (20) is installed on the cam guide pin (19), and the cam guide pin (19) drives the zoom lens group, the compensation lens group and the focusing lens group to move along the specified path under the driving of the zoom cam (16) and the focusing cam (13), to complete the zooming action.

5. The dynamically self-adapting backlash-free continuous zoom lens apparatus according to claim 4, wherein, The outer wall of the zoom lens outer frame (4) and the compensation lens frame (8) is provided with 4 symmetrically arranged sliding blocks, which cooperate with the inner cavity of the fixed lens barrel (14) to form a sliding guide rail.

6. The dynamically self-adapting backlash-free continuous zoom lens apparatus according to claim 5, wherein, The focusing lens outer frame (11) and the 4 evenly distributed focusing lens group sliding rails (30) form a sliding guide rail.

7. The dynamically self-adapting backlash-free continuous zoom lens apparatus according to claim 6, wherein, The 4 evenly distributed focusing lens group sliding rails (30) and the constant force magnetic spring and the cylindrical roller bearing (20) form a complementary and synergistic precision transmission system, and the symmetric constraint of the focusing lens group sliding rail (30) is used to uniformly distribute the pre-tightening force of the constant force magnetic spring on the cam groove contact surface, to avoid local wear caused by one-sided force, and to stably control the cooperation gap between the guide pin (19) and the cam groove.

8. The dynamically self-adapting backlash-free continuous zoom lens apparatus according to claim 2, wherein, Six linear guide grooves for limiting the movement of the cam guide pin (19) are symmetrically distributed along the circumference.

9. The dynamically self-adapting backlash-free continuous zoom lens arrangement according to any of claims 1-8, characterized in that, Further comprising focusing motor support (24), focusing gear (25), focusing motor (26), zoom motor support (27), zoom gear (28) and zoom motor (29); The focusing motor support (24) and the zoom motor support (27) are used to connect the focusing motor (26) and the zoom motor (29) to the fixed lens frame (12); the focusing gear (25) and the zoom gear (28) are used to engage with the racks distributed on the focusing cam (26) and the zoom cam (28), to drive the focusing cam (26) and the zoom cam (28) to rotate.

10. A zooming method of a dynamic self-adaptive backlash-free continuous zoom lens device according to any one of claims 1-9, characterized in that, The method comprises the following steps: (1) The focal length value and its corresponding control step, rotation angle relationship, starting and ending position parameters of the two cams are obtained by division; based on the focal length setting of the current field of view and the position data obtained by optical simulation, the accurate positions of the zoom lens assembly and the compensation lens assembly are determined, and then these position information is converted into servo control instructions of the zoom motor and the compensation motor; (2) The zoom motor and the compensation motor work in the specified direction and speed according to these signals; (3) The gears connected by the two motor shafts respectively engage with the racks distributed on the focusing cam and the zoom cam, and the power of these motors is transmitted to the zoom cam and the compensation cam to drive rotation; (4) The zoom lens group and the compensation lens assembly move along the cam curve groove satisfying a specific function relationship under the guidance of the cam guide pin; finally, these assemblies move linearly along the optical axis to the simulated set position, until the whole zooming process is successfully completed; (5) The image effect after zooming operation is observed, the gradient change amount of the image gray value is calculated according to the video frame content, and then the deviation amount between the actual focal length and the theoretical focal length is determined, and the focal length adjustment instruction is generated accordingly; (6) According to the focusing driving signal, the focusing cam also rotates, finally drives the focusing mirror to move to the preset target position accurately, so as to realize self-adaptive elimination of various gaps, fast high-precision focal length adjustment, and completion of continuous zoom of the infrared imaging system.

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