Intelligent assembling method of glass reference mirror

Abstract

The invention discloses an intelligent assembling method of a glass reference mirror, which utilizes an intelligent mechanical arm to complete the assembling of the glass reference mirror, utilizes a set of six-degree-of-freedom intelligent mechanical arm to complete the accurate position control of the glass reference mirror, and utilizes two sets of double-shaft photoelectric autocollimators to measure the orientation of the reference mirror. The position of the mechanical arm is adjusted through a central control closed-loop algorithm, and the glued surface of the reference mirror is aligned with the reference mirror mounting surface of the inertial attitude sensor, so that the reading of a reference collimator is the lowest, namely the precision is the highest, and the actual measurement precision can be within 15 seconds of arc. Meanwhile, by using the system, the thickness of the epoxy adhesive layer can be controlled through a known reference surface, and the temperature cycle of-35 DEG C to 70 DEG C can be resisted when the thickness of the adhesive film is 0.20 mm to 0.60 mm through test verification.

Description

Technical Field

[0001] The present application belongs to the field of inertia and relates to an intelligent assembly method of a glass reference mirror of an inertial attitude sensor. Background Art

[0002] Inertial attitude sensors are important sensors for satellite attitude control, guidance, and navigation. They can measure the satellite's rotation angle and linear motion relative to a fixed coordinate system. When installing an inertial attitude sensor on a satellite, a certain angular relationship needs to be established between it and the satellite. Typically, a glass or metal reference mirror is first installed on the inertial attitude sensor, and then the inertial attitude sensor with the reference mirror is mounted on the satellite. During installation, the reference mirror mounted on the inertial attitude sensor is aligned with the reference mirror on the satellite to determine the positional relationship between the inertial attitude sensor and the satellite, thereby ensuring the accuracy of the inertial attitude sensor's installation position on the satellite. Glass reference mirrors are relatively inexpensive, while metal reference mirrors are more than three times the price of glass mirrors, making them more popular.

[0003] The original installation method was purely manual. First, the inertial attitude sensor was fixed on the reference plane of the reference mirror assembly platform, and then the glass reference mirror was placed on the inertial attitude sensor through gluing. The angle between the reference mirror and the reference plane was detected and adjusted in time using components that can emit mutually perpendicular optical paths. This installation method requires the operator to have certain installation experience, and needs to use the help of a dual-axis photoelectric autocollimator for inspection and repeated adjustment. The operation efficiency is low and the installation accuracy is poor. The general accuracy is within 2 arc minutes, and the repeatability is not high.

[0004] The subsequent development is to use certain tooling to fix the reference mirror to the reference mirror mounting surface of the sensor. This method also has high labor requirements. The operator needs to carefully adjust the tooling of the reference mirror, and the installation accuracy is also limited by the material of the tooling.

[0005] This patent proposes an intelligent assembly method and system for a glass reference mirror. The system uses two sets of dual-axis photoelectric autocollimators to measure the orientation of the reference mirror. Then, through the central control system of the six-degree-of-freedom intelligent robotic arm, the robotic arm is adjusted through a closed-loop algorithm to minimize the reading of the reference collimator, that is, the highest accuracy. After actual measurement, the accuracy can reach within 15 arc seconds. Summary of the Invention

[0006] The technical problem solved by the present application is: to overcome the deficiencies of the prior art and provide an intelligent assembly method for a glass reference mirror, to achieve intelligent bonding of the glass reference mirror through a six-degree-of-freedom robotic arm, and to maximize the bonding accuracy of the reference mirror with the help of the high precision and high reliability of the robotic arm.

[0007] The technical solutions provided in this application are as follows:

[0008] An intelligent assembly method for a glass reference mirror employs an assembly system to assemble the reference mirror. The assembly system comprises a robotic arm, a dual-axis photoelectric autocollimator, and a main control system. The end of the robotic arm is connected to a reference mirror clamp. The dual-axis photoelectric autocollimator is used to measure the installation angle of the reference mirror and transmit the measurement results to the main control system. The main control system controls the movements of the robotic arm and the reference mirror clamp based on the measurement results of the dual-axis photoelectric autocollimator to complete the gripping, releasing, flipping, and movement of the reference mirror.

[0009] Methods include:

[0010] S1. Level the reference mirror mounting surface of the inertial attitude sensor, determine a bonding reference position P0 on the reference mirror mounting surface of the inertial attitude sensor, and place the reference mirror on the reference position P0 of the reference mirror mounting surface of the inertial attitude sensor, with the bonding surface P1 of the reference mirror facing the reference position P0.

[0011] S2, controlling the reference mirror clamp to clamp the reference mirror and drive the reference mirror away from the reference mirror mounting surface by a set distance;

[0012] S3. Coarsely adjust the position of the reference mirror so that the two dual-axis photoelectric autocollimators show readings; open the closed-loop control of the robotic arm and adjust the readings of the dual-axis photoelectric autocollimators to within 10 arc seconds;

[0013] S4. Measure the distance between the adhesive surface of the reference mirror and the adhesive surface of the inertial attitude sensor, confirm that the distance is within the preset range, and record the position of the reference mirror at this time as the initial position;

[0014] S5, controlling the reference mirror to move according to the glue coating track preset by the robot arm until the bonding surface P1 of the reference mirror faces upward;

[0015] S6. Apply epoxy glue evenly to the bonding surface P1 of the reference mirror and let it stand until the glue surface is smooth and flat.

[0016] S7, controlling the reference mirror to move to the initial position according to the bonding trajectory preset by the robotic arm;

[0017] S8. Check whether the reference mirror meets the position error of 10 arc seconds by reading the dual-axis photoelectric autocollimator. If not, open the closed-loop control of the manipulator and make fine adjustments until the requirement is met.

[0018] S9. Open the closed-loop control. The reference mirror will remain stationary by relying on the damping effect of the robotic arm until the epoxy glue is completely solidified. Open the reference mirror gripper of the robotic arm and return the robotic arm to its initial position to complete the installation of the reference mirror.

[0019] Furthermore, before use, the dual-axis photoelectric autocollimator is initially calibrated using a standard optical reference block so that the initial value is within 1 arc second.

[0020] Furthermore, in S2, the distance is set to 0.40 mm; and in S4, the preset range of the distance is 0.20 mm to 0.60 mm.

[0021] Furthermore, in S5, controlling the reference mirror to move according to the glue coating track preset by the robot arm until the bonding surface P1 of the reference mirror faces upward includes:

[0022] The clamped reference mirror is moved from the initial position to a direction away from the reference position P0, and then the reference mirror is rotated to a state where the bonding surface P1 faces upward.

[0023] Furthermore, in S7, the reference mirror is controlled to move to the initial position according to the bonding trajectory preset by the robot arm, including: driving the reference mirror to rotate until the bonding surface P1 faces the reference position P0, and then driving the reference mirror to move in a direction close to the reference position P0 until the reference mirror moves to the initial position.

[0024] Furthermore, in S6, the epoxy glue is evenly applied to the bonding surface P1 of the reference mirror and allowed to stand until the glue surface is smooth and flat, including: the epoxy glue is a two-component epoxy glue, the two-component epoxy glue is mixed in corresponding proportions and stirred evenly, and allowed to stand for 40 to 60 minutes to obtain the prepared epoxy glue; the prepared epoxy glue is evenly applied to the bonding surface P1 of the reference mirror and allowed to stand for 5 to 10 minutes until the glue surface is smooth and flat.

[0025] Furthermore, the closed-loop control transfer function of the robotic arm is:

[0026]

[0027] Where K = 2.5 to 10, s is the pole and zero of the transfer function G1(s), and m is 2×10 3 .

[0028] Furthermore, the contact surface between the reference mirror clamp and the glass is made of hard rubber, and the hardness of the hard rubber is 35-40.

[0029] Furthermore, the dual-axis photoelectric autocollimator has an angular measurement accuracy of 1 arc second and a measurement field range of 2000 arc seconds.

[0030] This system utilizes a six-degree-of-freedom intelligent robotic arm to precisely control the position of a glass reference mirror. Two dual-axis photoelectric autocollimators measure the reference mirror's orientation. A closed-loop algorithm controlled by the central control adjusts the position of the robotic arm, aligning the reference mirror's adhesive-coated surface with the inertial attitude sensor's reference mirror mounting surface. This minimizes the reference collimator's reading, achieving the highest accuracy. Measured accuracy has reached within 15 arc seconds. Furthermore, this system can control the thickness of the epoxy adhesive layer using a known reference surface. Tests have shown that the adhesive can withstand temperature cycles from -35°C to 70°C when the film thickness ranges from 0.20mm to 0.60mm.

[0031] In summary, this application has at least the following beneficial technical effects:

[0032] 1. The reference mirror is assembled using a robotic arm. After the reference mirror is adjusted, there is no need for operators to make subsequent continuous adjustments and calibrations, saving a lot of human resources;

[0033] 2. The use of a robotic arm to assemble the reference mirror ensures a high degree of consistency in the accuracy of the reference mirror, improving the installation accuracy of the traditional reference mirror from 2 arc minutes to 15 arc seconds;

[0034] 3. Using a robotic arm to assemble a reference mirror can control the thickness of the epoxy film. Tests have shown that when the film is between 0.2mm and 0.60mm, it can withstand temperature cycles of -35℃ to 70℃. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 Structural diagram of the intelligent installation system for the reference mirror.

[0036] Figure 2 Intelligent installation system main control interface.

[0037] Figure 3 Intelligent installation system trajectory planning interface.

[0038] Figure 4 Schematic diagram of the position of the gripper holding the reference mirror.

[0039] Figure 5 Schematic diagram of the position of the reference mirror in the coordinate system. DETAILED DESCRIPTION

[0040] In order to make the objectives, technical solutions and advantages of this application clearer, the embodiments disclosed in this application will be described in further detail below with reference to the accompanying drawings.

[0041] The embodiment of the present application discloses an intelligent assembly method for a glass reference mirror, which uses an assembly system to assemble the reference mirror, such as Figure 1As shown in the figure, the system includes a main control system, a robotic arm, a reference mirror gripper, and a dual-axis photoelectric autocollimator. The main control system is an industrial computer that runs the control software of the intelligent system. The main interface is as follows: Figure 2 The robotic arm has six degrees of freedom, with a reference mirror gripper at its end. A dual-axis photoelectric autocollimator measures the reference mirror's installation angle and transmits the results to the main control system. The main control system controls the movement of the robotic arm and the reference mirror gripper based on the dual-axis photoelectric autocollimator's measurements, thereby enabling the gripping, release, flipping, and movement of the reference mirror.

[0042] The accuracy of manually installed reference mirrors is 2 arc minutes, and the joint rotation accuracy of the robot arm must be better than the accuracy of manually installed reference mirrors. The installation process of the reference mirror is divided into initial alignment and installation with glue, so the robot arm must have high position repeatability. During the curing process of the reference mirror adhesive, the reference mirror must remain fixed, otherwise it will affect the curing of the epoxy adhesive.

[0043] Based on the above conditions, the key indicators of the robotic arm are as follows:

[0044] Degrees of freedom: 6; positioning accuracy and repeatability: ±0.02mm; single joint stepping accuracy: 3.6 arc seconds; payload: 3kg; each joint has damping function.

[0045] Static stability: Each joint of the robotic arm has damping characteristics, which prevents the robotic arm from producing micro-movements due to the position, speed, and current loop of the motor. When the robotic arm is in a stationary state, the front-end gripper of the robotic arm can ensure stability and motionlessness, without affecting the curing process of the epoxy adhesive, thus ensuring high bonding accuracy during the curing process of the epoxy adhesive.

[0046] Since the object to be clamped is glass and the reference mirror must maintain a certain posture accuracy during the clamping process, the contact surface between the clamping jaws and the glass is required to be hard rubber with a hardness of 35-40.

[0047] The dual-axis photoelectric autocollimator has an angular measurement accuracy of 1 arc second and a measurement field of view of 2000 arc seconds, making it easier for the system to enter the closed-loop initial state and providing a wide adjustment range. The dual-axis photoelectric autocollimator has a remote data acquisition function, and its measured angle information is transmitted to the system's main control system via the RS232 / USB interface. The main control system then completes closed-loop azimuth adjustment of the robotic arm based on the azimuth data of the reference mirror until the installation index requirements of the reference mirror are met.

[0048] The trajectory control interface during the intelligent installation of the reference mirror is as follows: Figure 3 As shown, through this interface, the robot arm can be connected, powered on, and enabled, and the tool end can be moved in space, the position and posture can be fine-tuned, and the robot status can be detected.

[0049] The trajectory of the robotic arm is divided into two processes: bonding and gluing. First, a bonding reference position P0 must be determined on the mounting surface of the reference mirror of the inertial attitude sensor. The reference position P0 is horizontal and facing upwards. The surface where the reference mirror and the reference position P0 are bonded is the bonding surface P1. At this time, it is necessary to ensure that the distance between the bonding surface P1 of the reference mirror and the bonding surface of the inertial attitude sensor is between 0.20mm and 0.60mm (that is, the initial position of the reference mirror is: the bonding surface P1 of the reference mirror is directly opposite the reference position P0, and the distance between the bonding surface P1 and the reference position P0 is 0.20mm to 0.60mm). The gluing trajectory is executed with the bonding surface P1 of the reference mirror as the bonding reference position. The gluing trajectory is: starting from the initial position, move the clamped reference mirror away from the reference position P0, and then place the bonding surface P1 in a state facing upwards to facilitate the operator to apply glue. After gluing, let it stand for a set time until the glue surface is smooth and flat, and then proceed with the bonding trajectory. The bonding track is the reverse track of the gluing process. Through the bonding track, the robotic arm moves the glued reference mirror to the initial position state of the reference mirror.

[0050] Typically, the glue needs to be applied within 40 to 60 minutes of mixing the two components, followed by a 5 to 10 minute rest period before the bonding process is completed. The epoxy adhesive's bond thickness, 0.20 mm to 0.60 mm, is a critical parameter for ensuring bonding quality. This range ensures that the reference mirror of the inertial attitude sensor will not fall or break when subjected to temperatures between -35°C and 70°C. The application time after mixing the two-component epoxy adhesive and the rest time between application and bonding are key parameters. The bonding process involves flipping the reference mirror, requiring the epoxy adhesive to maintain a viscosity between 10 and 20 Pa·s to prevent excessive flow during flipping. However, the epoxy adhesive should be moderately thick, as this would hinder fine-tuning after the bonding process.

[0051] The system has a closed-loop fine-tuning function, which ensures that the readings of the dual-axis photoelectric autocollimator in both directions are within 10 arc seconds (epoxy adhesive will produce a drift of about 3 arc seconds during the long curing process); the system has the function of robot arm trajectory planning, which can easily make any necessary adjustments to the trajectory.

[0052] At the reference position P0, it is necessary to ensure that the alignment accuracy of the reference mirror can be adjusted to meet 10 arc seconds, and then the minimum error can be guaranteed after the subsequent gluing and bonding track. Because the end of the robot arm cannot move in a large range after gluing, otherwise it will cause bubbles in the epoxy glue layer.

[0053] The closed-loop control transfer function is as follows:

[0054]

[0055] In this embodiment, m is 2×10 3 , the closed-loop control transfer function is:

[0056]

[0057] Where K = 2.5, m needs to be fine-tuned for each system according to the actual situation; s is the pole and zero of the transfer function G1(s).

[0058] This embodiment also provides a method for intelligently assembling a glass reference mirror, comprising:

[0059] Mix the two-component epoxy adhesive in corresponding proportions, stir evenly, and let it stand for 40 to 60 minutes.

[0060] Using the waiting time, the dual-axis photoelectric autocollimator is initially calibrated with a standard optical reference block so that the initial value is within 1 arc second.

[0061] Place the inertial attitude sensor on the reference surface of the operating table, align the reference surface of the inertial attitude sensor with the reference surface of the operating table, and place the glass reference mirror on the reference mirror installation surface of the inertial attitude sensor.

[0062] Control the robotic arm to clamp the reference mirror. The reference mirror gripper can only clamp about 1 / 3 of the upper part of the reference mirror. This surface needs to leave 10mm of measurement space for the dual-axis photoelectric autocollimator; Figure 4 and Figure 5 As shown, the YOZ plane is parallel to the reference mirror mounting surface of the inertial attitude sensor;

[0063] In such Figure 5 In the coordinate system, lift the robot arm 0.40 mm along the X direction.

[0064] Manual coarse adjustment: Adjust the position X, Y and attitude RX, RY, RZ of the reference mirror so that the two dual-axis photoelectric autocollimators show readings.

[0065] Closed-loop fine-tuning: Open the closed-loop control of the manipulator and adjust the readings of the dual-axis photoelectric autocollimator to within 10 arc seconds. The closed-loop control transfer function is as follows:

[0066]

[0067] Among them, K = 2.5 ~ 10, for each system m needs to be fine-tuned according to the actual situation.

[0068] Use a feeler gauge to measure the distance between the reference mirror adhesive surface and the inertial attitude sensor bonding surface and confirm that it is within the range of 0.20mm to 0.60mm.

[0069] Record the current bonding reference position as P0.

[0070] According to the pre-designed trajectory, the end of the robotic arm is flipped 180 degrees so that the adhesive surface of the reference mirror faces upward.

[0071] Wait for 40 to 60 minutes for the epoxy glue to meet the requirements, then evenly apply an appropriate amount of epoxy glue (determined according to the thickness of the glue layer and the bonding area of the reference mirror) to the bonding surface of the reference mirror and let it stand for 5 to 10 minutes until the glue surface is smooth and flat.

[0072] Retrieve the bonding trajectory curve to return the reference mirror to the original P0 point.

[0073] Observe the readings of the two dual-axis photoelectric autocollimators to see if they meet the 10 arc second error. If not, open the closed-loop control and make fine adjustments until the requirements are met.

[0074] When the closed-loop control is turned on, the reference mirror will remain stationary by relying on the damping effect of the robotic arm until the epoxy glue is completely solidified after 4 hours.

[0075] Open the gripper of the robotic arm and return the robotic arm to its initial position to complete the installation of the reference mirror.

[0076] The contents not described in detail in this application specification are common knowledge to those skilled in the art.

[0077] The present application has been described in detail above with reference to specific embodiments and exemplary examples. However, these descriptions should not be construed as limiting the present application. Those skilled in the art will appreciate that, without departing from the spirit and scope of the present application, various equivalent substitutions, modifications, or improvements may be made to the technical solutions and implementations of the present application, all of which fall within the scope of the present application. The scope of protection of the present application shall be determined by the appended claims.

Claims

1. An intelligent assembly method for a glass reference mirror, characterized in that: The reference mirror is assembled using an assembly system that includes a robotic arm, a dual-axis photoelectric autocollimator, and a main control system. The end of the robotic arm is connected to the reference mirror gripper. The dual-axis photoelectric autocollimator is used to measure the installation angle of the reference mirror and send the measurement results to the main control system. The main control system is used to control the movement of the robotic arm and the reference mirror gripper based on the measurement results of the dual-axis photoelectric autocollimator to complete the gripping, releasing, flipping, and moving of the reference mirror. Methods include: S1. Level the reference mirror mounting surface of the inertial attitude sensor, determine a bonding reference position P0 on the reference mirror mounting surface of the inertial attitude sensor, and place the reference mirror on the reference position P0 of the reference mirror mounting surface of the inertial attitude sensor, with the bonding surface P1 of the reference mirror facing the reference position P0. S2, controlling the reference mirror clamp to clamp the reference mirror and drive the reference mirror away from the reference mirror mounting surface by a set distance; S3. Coarsely adjust the position of the reference mirror so that the two dual-axis photoelectric autocollimators show readings; open the closed-loop control of the robotic arm and adjust the readings of the dual-axis photoelectric autocollimators to within 10 arc seconds; S4. Measure the distance between the adhesive surface of the reference mirror and the adhesive surface of the inertial attitude sensor, confirm that the distance is within the preset range, and record the position of the reference mirror at this time as the initial position; S5, controlling the reference mirror to move according to the glue coating track preset by the robot arm until the bonding surface P1 of the reference mirror faces upward; S6. Apply epoxy glue evenly to the bonding surface P1 of the reference mirror and let it stand until the glue surface is smooth and flat. S7, controlling the reference mirror to move to the initial position according to the bonding trajectory preset by the robotic arm; S8. Check whether the reference mirror meets the position error of 10 arc seconds by reading the dual-axis photoelectric autocollimator. If not, open the closed-loop control of the manipulator and make fine adjustments until the requirement is met. S9. Open the closed-loop control. The reference mirror will remain stationary by relying on the damping effect of the robotic arm until the epoxy glue is completely solidified. Open the reference mirror gripper of the robotic arm and return the robotic arm to its initial position to complete the installation of the reference mirror.

2. The intelligent assembly method of a glass reference mirror according to claim 1, characterized in that: Before use, the dual-axis photoelectric autocollimator is initially calibrated using a standard optical reference block so that the initial value is within 1 arc second.

3. The intelligent assembly method of a glass reference mirror according to claim 1, characterized in that: In S2, the distance is set to 0.40 mm; in S4, the preset range of the distance is 0.20 mm to 0.60 mm.

4. The intelligent assembly method of a glass reference mirror according to claim 1, characterized in that: In the above S5, the reference mirror is controlled to move according to the glue coating track preset by the robot arm until the bonding surface P1 of the reference mirror faces upward, including: The clamped reference mirror is moved from the initial position to a direction away from the reference position P0, and then the reference mirror is rotated to a state where the bonding surface P1 faces upward.

5. The intelligent assembly method of a glass reference mirror according to claim 1, characterized in that: In said S7, the reference mirror is controlled to move to the initial position according to the bonding trajectory preset by the robot arm, including: driving the reference mirror to rotate until the bonding surface P1 faces the reference position P0, and then driving the reference mirror to move in a direction close to the reference position P0 until the reference mirror moves to the initial position.

6. The intelligent assembly method of a glass reference mirror according to claim 1, characterized in that: In the above-mentioned S6, the epoxy glue is evenly applied to the bonding surface P1 of the reference mirror, and the epoxy glue is allowed to stand until the glue surface is smooth and flat, including: the epoxy glue is a two-component epoxy glue, the two-component epoxy glue is mixed in corresponding proportions and stirred evenly, and the epoxy glue is allowed to stand for 40 to 60 minutes to obtain the prepared epoxy glue; the prepared epoxy glue is evenly applied to the bonding surface P1 of the reference mirror, and the epoxy glue is allowed to stand until the glue surface is smooth and flat and the viscosity is between 10 and 20 Pa·s.

7. The intelligent assembly method of a glass reference mirror according to claim 1, characterized in that: The closed-loop control transfer function of the robotic arm is: Where K = 2.5 to 10, s is the pole and zero of the transfer function G1(s), and m is 2×10 3 .

8. The intelligent assembly method of a glass reference mirror according to claim 1, characterized in that: The contact surface between the reference mirror clamping claw and the glass is hard rubber, and the hardness of the hard rubber is 35-40.

9. The intelligent assembly method of a glass reference mirror according to claim 1, characterized in that: The dual-axis photoelectric autocollimator has an angular measurement accuracy of 1 arc second and a measurement field range of 2000 arc seconds.

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