Micro-motion control device for online compensation of optical axis deviation

Abstract

The invention discloses a micro-motion control device for online compensation of optical axis offset, which comprises an optical end mechanism and a base, a plurality of micro-motion driving rods are connected in parallel between the optical end mechanism and the base, a plurality of micro-displacement sensors are arranged on one side of the optical end mechanism, and the optical end mechanism comprises a mirror frame. According to the invention, the optical tail end mechanism, the micro-motion driving rods and the micro-displacement sensor are arranged and are matched with one another, and the lengths of the six micro-motion driving rods are respectively adjusted, so that the lens can be driven to realize any posture on six degrees of freedom in a small range, and meanwhile, measured data can be compensated in real time through feedback closed-loop control; the infrared imaging system has the advantages that the control precision is improved, the optical axis deviation of the infrared imaging system caused by the heat effect can be compensated, the optical lens can be controlled in a closed-loop manner by arranging the measuring element and the feedback ring, the control precision of the whole equipment is high, the stability can be kept in a complex mechanical environment, and the imaging quality of the system is ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of infrared imaging devices. More specifically, the present invention is a fine motion control device for online compensation of optical axis offset. Background Art

[0002] During the imaging process of a general infrared imaging system, temperature changes in the working environment and heat generation in the internal imaging circuit often cause non-uniform deformation of the imaging system structure, resulting in the offset of the optical components of the imaging system and affecting the optical axis stability and imaging effect of the imaging system. To solve the problem of optical axis drift under thermal effects, the infrared imaging system usually selects a centrosymmetric structure form such as cam drive to avoid asymmetric deformation.

[0003] However, the overall mechanical properties of this structure form are poor at present, the working temperature range is narrow, it is greatly affected by temperature, and at the same time, the design difficulty of the structure is greatly increased. The present invention provides a new fine motion control device for online compensation of optical axis offset to increase the working temperature threshold of its imaging system. Summary of the Invention

[0004] To overcome the above-mentioned defects of the prior art, an embodiment of the present invention provides a fine motion control device for online compensation of optical axis offset. By setting an optical end mechanism, a fine motion drive rod, and a micro displacement sensor, and using their mutual cooperation, the lengths of six fine motion drive rods are adjusted respectively, so as to drive the lens to achieve any attitude in six degrees of freedom within a small range. There are six micro displacement sensors on the outer side of the lens frame. Three of the sensors jointly measure the eccentric displacement of the lens, and the other three sensors jointly measure the angular tilt of the lens. At the same time, the measurement data of the six sensors can be compensated in real time through feedback closed-loop control to improve the control accuracy, and can compensate for the optical axis offset generated by the thermal effect of the infrared imaging system. At the same time, by setting a measurement element and a feedback loop, the optical lens can be controlled in a closed loop, so that the overall device has high control accuracy, can remain stable in a complex mechanical environment, and ensure the imaging quality of the system, so as to solve the problems raised in the above background art.

[0005] To achieve the above object, the present invention provides the following technical solution: A fine motion control device for online compensating the optical axis offset, comprising an optical end mechanism and a base. A plurality of fine motion drive rods are connected in parallel between the optical end mechanism and the base. A plurality of micro displacement sensors are arranged on one side of the optical end mechanism. The optical end mechanism includes a frame. A plurality of outer spherical hinge points of the frame, an axial measurement target block and a radial measurement target block are respectively arranged on the outer side of the optical end mechanism. An optical element is fixed inside the frame. The base includes a main frame. A plurality of base spherical hinge points and axial probe supports are arranged equidistantly inside the main frame. A plurality of radial probe supports are arranged on the outer side of the main frame. The fine motion drive rod includes a piezoelectric actuator and a spherical hinge. The two ends of the fine motion drive rod are respectively connected to the frame and the base through spherical hinges.

[0006] In a preferred embodiment, the number of the fine motion drive rods is six, and the six fine motion drive rods are evenly distributed equidistantly in the circumferential direction on the inner wall of the base.

[0007] In a preferred embodiment, the six fine motion drive rods contract or extend according to given different parameters to reach a preset rod length, so as to adjust the six-degree-of-freedom spatial attitude of the optical end mechanism.

[0008] In a preferred embodiment, the micro displacement sensor measures the distances from the axial measurement target block and the radial measurement target block and outputs signals. After signal processing, the displacement amount of the measurement target block can be obtained and converted into the eccentricity and angular tilt amount of the optical end mechanism. And the signals output by the micro displacement sensor can be used as feedback signals of the fine motion drive rod, so as to realize the closed-loop control of the spatial attitude of the optical end mechanism.

[0009] In a preferred embodiment, the optical end mechanism and the base can be connected by parallel or hybrid drive through a plurality of fine motion drive rods, so as to adjust the spatial attitude of the optical end mechanism.

[0010] In a preferred embodiment, the two ends of the fine motion drive rod can be fixed on the inner walls of the base and the optical end mechanism by any one of spherical hinge connection, link connection or mixed connection. The micro displacement sensor can be a capacitive sensor or an eddy current sensor. The signals of the micro displacement sensor can be used as feedback signals of the fine motion drive rod or only as real-time measurement value references. The optical element in the optical end mechanism can specifically be a lens or a mirror.

[0011] The technical effects and advantages of the present invention:

[0012] The present invention realizes arbitrary postures of a lens within a small range in six degrees of freedom by setting an optical end mechanism, a micro-motion driving rod, and a micro-displacement sensor, and through the mutual cooperation among them. By adjusting the lengths of the six micro-motion driving rods respectively, six micro-displacement sensors are arranged on the outer side of the lens frame. Among them, three sensors jointly measure the eccentric displacement of the lens, and the other three sensors jointly measure the angular tilt of the lens, so as to measure the real-time data of the position and posture of the lens. At the same time, the measured data can be compensated in real time through feedback closed-loop control to improve the control accuracy, and can compensate for the optical axis offset generated by the thermal effect of the infrared imaging system. At the same time, by setting the measuring element and the feedback loop, the optical lens can be controlled in a closed loop, so that the overall equipment has high control accuracy, the micro-motion control device has high overall stiffness, and can remain stable in a complex mechanical environment, ensuring the imaging quality of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a schematic diagram of the overall structure of the present invention;

[0014] Figure 2 is a schematic diagram of the back structure of the present invention;

[0015] Figure 3 is a schematic diagram of the overall structure of the optical end mechanism of the present invention;

[0016] Figure 4 is a three-dimensional structure schematic diagram of the micro-motion driving rod of the present invention.

[0017] The reference numerals are: 1, optical end mechanism; 2, base; 3, micro-motion driving rod; 4, micro-displacement sensor; 11, lens frame; 12, spherical hinge fulcrum on the outer side of the lens frame; 13, axial measurement target block; 14, radial measurement target block; 15, optical element; 21, main frame; 22, spherical hinge fulcrum of the base; 23, axial probe support; 24, radial probe support; 31, piezoelectric actuator; 32, spherical hinge. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0018] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0019] As shown in the attached Figure 1 to the attached Figure 4A kind of micro-motion control device for online compensating the optical axis offset, comprising an optical end mechanism 1 and a base 2. A plurality of micro-motion driving rods 3 are connected in parallel between the optical end mechanism 1 and the base 2. A plurality of micro-displacement sensors 4 are arranged on one side of the optical end mechanism 1. The optical end mechanism 1 includes a lens frame 11. A plurality of outer ball hinge fulcrums 12, an axial measurement target block 13 and a radial measurement target block 14 are respectively arranged on the outer side of the optical end mechanism 1. An optical element 15 is fixed inside the lens frame 11. The base 2 includes a main frame 21. A plurality of base ball hinge fulcrums 22 and an axial probe support 23 are arranged equidistantly inside the main frame 21. A plurality of radial probe supports 24 are arranged on the outer side of the main frame 21. The micro-motion driving rod 3 includes a piezoelectric actuator 31 and a ball hinge 32. The two ends of the micro-motion driving rod 3 are respectively connected to the lens frame 11 and the base 2 through the ball hinge 32.

[0020] The micro-displacement sensor 4 measures the distances from the axial measurement target block 13 and the radial measurement target block 14 and outputs signals. After signal processing, the displacement of the measurement target block can be obtained, and is converted into the eccentricity and angular tilt of the optical end mechanism 1. And the signals output by the micro-displacement sensor 4 can be used as the feedback signals of the micro-motion driving rod 3, so as to realize the closed-loop control of the spatial attitude of the optical end mechanism 1. The optical end mechanism 1 and the base 2 can be connected in parallel or in a hybrid drive connection through a plurality of micro-motion driving rods 3, so as to adjust the spatial attitude of the optical end mechanism 1. The two ends of the micro-motion driving rod 3 can be fixed on the inner wall of the base 2 and the optical end mechanism 1 by any one of ball hinge connection, link connection or mixed connection. The micro-displacement sensor 4 can be a capacitive sensor or an eddy current sensor. The signals of the micro-displacement sensor 4 can be used as the feedback signals of the micro-motion driving rod 3, or can only be used as the reference of real-time measurement values. The optical element 15 in the optical end mechanism 1 can specifically be a lens or a mirror.

[0021] Among them, the piezoelectric actuator 31 is a device that utilizes the piezoelectric effect or the inverse piezoelectric effect to generate displacement or force. The piezoelectric effect refers to the phenomenon that certain crystal materials undergo dimensional changes when subjected to external forces, while the inverse piezoelectric effect means that when an electric field is applied, the crystal material will generate deformation. The piezoelectric actuator 31 is usually composed of piezoelectric ceramics and electrodes. When a voltage is applied to the electrodes, the piezoelectric ceramics around the electrodes will undergo dimensional changes or deformations, thereby generating displacement or force. The working principle of the piezoelectric actuator 31 can be divided into two cases: force generation and displacement generation. In the piezoelectric actuator 31 for force generation, when a voltage is applied, the piezoelectric ceramics around the electrodes deform to form a force, which can be used to drive the movement of mechanical components or for other applications that require force. In the piezoelectric actuator 31 for displacement generation, when a voltage is applied, the piezoelectric ceramics and the mechanical components connected thereto deform, thereby generating displacement, which can be used to precisely control the position of mechanical components or for other applications that require position control; The piezoelectric actuator 31 has many advantages, including fast response, high precision, high load capacity, etc. Due to these characteristics, piezoelectric actuators are widely used in medical equipment, precision instruments, mechanical automation and other fields. In addition, the piezoelectric actuator 31 can also provide an alternative solution for electromagnetic devices, with advantages such as higher reliability, lower power consumption, smaller size and higher position resolution.

[0022] The micro displacement sensor 4 uses a capacitive distance sensor. The working principle of the capacitive distance sensor is based on the principle of capacitance change, and the distance of an object is measured by measuring the change in capacitance value. Its basic structure includes a fixed electrode (static capacitor plate) and a floating electrode (movable capacitor plate), which are separated by an insulating material (such as air or plastic) to form a capacitor. When the object to be measured undergoes displacement, the floating plate will move accordingly, resulting in a change in the distance between it and the fixed plate, and further causing a change in the capacitance value of the capacitor.

[0023] The working principle of its capacitive distance sensor is as follows:

[0024] Capacitance change: When there is no displacement, the distance between the fixed plate and the floating plate is fixed, so the capacitance value between them is also constant. However, when the object to be measured undergoes displacement, the floating plate will move accordingly, resulting in a change in the distance between it and the fixed plate. This change in distance will cause a change in the capacitance value of the capacitor. Specifically, when the floating plate approaches the fixed plate, the capacitance value increases; when the floating plate moves away from the fixed plate, the capacitance value decreases;

[0025] Capacitance detection: In order to measure the change in capacitance value, circuit forms such as bridge circuits and oscillation circuits are usually used to convert the change in capacitance value into an electrical signal (such as voltage, current or frequency) that is easy to measure;

[0026] Displacement calculation: According to the inverse relationship between the capacitance value and the distance between the electrodes, the sensor calculates the displacement of the object by measuring the change in capacitance value. This calculation is usually completed by an internal microprocessor or a dedicated signal processing circuit, which can convert the change in capacitance value into the corresponding displacement value and output it in the form of digital or analog signals. The capacitive distance sensor has the advantages of high precision, fast response, and non-contact measurement. Therefore, it can be used to measure parameters such as displacement, motion, and vibration in mechanical systems for precise positioning and control.

[0027] For specific reference, please refer to the attached Figures 1 - 3 There are six micro-motion drive rods 3. The six micro-motion drive rods 3 are evenly distributed at equal intervals in the circumferential direction on the inner wall of the base 2. The six micro-motion drive rods 3 contract or extend according to given different parameters to reach the preset rod length, so as to adjust the six-degree-of-freedom spatial attitude of the optical end mechanism 1.

[0028] The specific implementation method is as follows: By using the setting of multiple micro-motion drive rods 3, the measurement data can be compensated in real time through feedback closed-loop control, improving the control accuracy, and being able to compensate for the optical axis offset generated by the thermal effect of the infrared imaging system, and can remain stable in a complex mechanical environment to ensure the imaging quality of the system.

[0029] The working principle of the present invention:

[0030] The first step: First, the operator normally assembles each component of the device and then uses the device normally.

[0031] The second step: Based on piezoelectric actuation technology, the control device can adjust the attitude of the optical system lens at the um level, thereby accurately compensating for the optical axis offset of the infrared imaging system. The frame 11 and the base 2 are connected in parallel by six micro-motion drive rods 3. Ball joints 32 are provided at both ends of the six micro-motion drive rods 3 to connect with the frame 11 and the base 2. By respectively adjusting the lengths of the six micro-motion drive rods 3, the lens can be driven to achieve any attitude in six degrees of freedom within a small range. Six micro-displacement sensors 4 are provided outside the frame 11. Among them, three micro-displacement sensors 4 jointly measure the eccentric displacement of the lens, and the other three micro-displacement sensors 4 jointly measure the angular tilt of the lens, so as to measure the real-time data of the position and attitude of the lens. At the same time, the measurement data can be compensated in real time through feedback closed-loop control to improve the control accuracy. The present invention can be used for each individual optical lens in the infrared imaging system, including fixed group lenses, zoom group lenses, compensation group lenses, focusing group lenses, and mirrors.

[0032] The third step: First, the operator normally shuts down the device, then checks whether the fixation between the components of the device is normal, and then replaces and repairs the aging and severely worn parts inside the device.

[0033] The following are several points that should be noted: First, in the description of this application, it should be noted that unless otherwise specified and defined, the terms "installed", "connected", and "coupled" should be understood in a broad sense. It can be a mechanical connection or an electrical connection, or it can be the communication inside two components. It can be directly connected. The terms "upper", "lower", "left", "right", etc. are only used to represent relative positional relationships. When the absolute position of the object being described changes, the relative positional relationship may change;

[0034] Second: In the drawings of the disclosed embodiments of the present invention, only the structures related to the disclosed embodiments are involved. For other structures, reference can be made to the usual designs. Without conflict, the same embodiment and different embodiments of the present invention can be combined with each other;

[0035] Finally: The above description is only the preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A micro-motion control device for online compensation of optical axis deviation, characterized in that: It includes an optical terminal mechanism and a base, a plurality of micro-drive rods are connected in parallel between the optical terminal mechanism and the base, a plurality of micro-displacement sensors are arranged on one side of the optical terminal mechanism, the optical terminal mechanism includes a mirror frame, a plurality of mirror frame outer side ball joint fulcrums, axial measurement target blocks and radial measurement target blocks are arranged on the outer side of the optical terminal mechanism, an optical element is fixed on the inner side of the mirror frame, the base includes a main frame, a plurality of base ball joint fulcrums and axial probe brackets are equidistantly arranged on the inner side of the main frame, a plurality of radial probe brackets are arranged on the outer side of the main frame, the micro-drive rod includes a piezoelectric actuator and a ball joint, and both ends of the micro-drive rod are connected to the mirror frame and the base respectively through ball joints.

2. The micro-motion control device for online compensation of optical axis deviation according to claim 1, characterized in that: The number of the micro-motion driving rods is six, and the six micro-motion driving rods are evenly distributed on the inner wall of the base in the outer circumferential direction at equal intervals.

3. The micro-motion control device for online compensation of optical axis deviation according to claim 2, characterized in that: The six micro-motion driving rods are contracted or extended according to given different parameters to achieve a preset rod length, thereby adjusting the six-degree-of-freedom spatial posture of the optical terminal mechanism.

4. The micro-motion control device for online compensation of optical axis deviation according to claim 1, characterized in that: The micro-displacement sensor measures the distance to the axial measurement target block and the radial measurement target block and outputs a signal. After signal processing, the displacement of the measurement target block can be obtained and converted into the eccentricity and angular inclination of the optical terminal mechanism. The signal output by the micro-displacement sensor can be used as a feedback signal of the micro-drive rod, thereby realizing the closed-loop control of the spatial attitude of the optical terminal mechanism.

5. The micro-motion control device for online compensation of optical axis deviation according to claim 1, characterized in that: The optical terminal mechanism and the base can be connected in parallel or in hybrid driving via a plurality of micro-motion driving rods, so as to adjust the spatial posture of the optical terminal mechanism.

6. The micro-motion control device for online compensation of optical axis deviation according to claim 1, characterized in that: The two ends of the micro-motion drive rod can be fixed on the base and the inner wall of the optical terminal mechanism by any of ball joint connection, connecting rod connection or mixed connection. The micro-displacement sensor can adopt a capacitive sensor or an eddy current sensor. The signal of the micro-displacement sensor can be used as a feedback signal of the micro-motion drive rod, or only as a reference for real-time measurement values. The optical element in the optical terminal mechanism can specifically be a lens or a reflector.

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