Gravity unloading precision control method for large flexible reflecting surface

Abstract

The invention provides a gravity unloading precision control method for a large flexible reflecting surface. The gravity unloading precision control method comprises a hanging disturbing force reduction method, a system disturbing force compensation method and a reflecting surface hanging point active following method which are executed in sequence. The method has the beneficial effects that the hanging disturbance force is reduced through the method, the unloading precision can meet the requirement of unfolding root hinge disturbance torque through system disturbance force compensation and reflection surface hanging point active following, the problems of reflection surface mass center drifting and unloading force instability can be avoided in the unfolding process, and the unloading precision is improved.

Description

Technical Field

[0001] The invention belongs to the field of micro-low gravity technology, and in particular relates to a method for controlling the gravity unloading accuracy of a large-scale flexible reflecting surface. Background Art

[0002] Large flexible reflective surfaces are large in size, heavy in weight, and weak in rigidity. During zero-gravity deployment tests, due to their large size and long lever arm, the unloading accuracy that can be achieved by traditional methods cannot meet the requirements of the root hinge interference torque of the deployment. In addition, during the deployment process, due to their weak rigidity, deformation and flutter are prone to occur, which causes the center of mass of the reflective surface to drift and the unloading force to be unstable, resulting in reduced unloading accuracy. Therefore, a gravity unloading accuracy control method for large flexible reflective surfaces is proposed. Summary of the invention

[0003] In view of this, the present invention aims to provide a method for controlling the gravity unloading accuracy of a large flexible reflective surface, so as to solve at least one problem existing in the above-mentioned prior art.

[0004] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0005] A method for controlling the gravity unloading accuracy of a large flexible reflective surface, comprising a method for reducing the hanging interference force, a method for compensating the system interference force, and a method for actively following the hanging point of the reflective surface, which are executed in sequence;

[0006] The method for reducing the suspension interference force comprises the following steps:

[0007] A1. The pulley adopts air flotation lubrication to reduce the friction of the pulley;

[0008] A2. Select the rope with the least influence on the hanging resistance through the hanging resistance test;

[0009] System disturbance force compensation methods include:

[0010] B1. Hanging resistance test;

[0011] B2, adjusting the centroid of the reflecting surface;

[0012] B3. Expand the reflective surface through the reflective surface expansion process equipment, and measure the comprehensive resistance of the reflective surface expansion process;

[0013] B4. Counterweight calculation;

[0014] B5. Fine-tune the weight;

[0015] The active following method of the reflective surface hanging point includes the following steps:

[0016] C1. Adjust the suspension rope vertically;

[0017] C2, system initialization;

[0018] C3, enter follow mode;

[0019] C4, the reflective surface unfolding motor starts;

[0020] C5, the hanging point follows automatically.

[0021] Furthermore, in step B1, the hanging resistance test is performed using a push-pull dynamometer or an indirect test using a bench scale.

[0022] Further, in step B2, the centroid of the reflective surface is adjusted by using a counterweight to adjust the centroid of the reflective surface to the center of the hanging shaft, so that the influence of the centroid deviation of the reflective surface on the unloading accuracy is minimized. The adjustment method is that the reflective surface is in a suspended state, and the counterweight is used to adjust the reflective surface to be level in both horizontal and vertical states, and an inclinometer is used to measure whether it is adjusted to be level;

[0023] Further, in step B3, the comprehensive resistance of the reflective surface during deployment refers to the comprehensive influence of the flexible deformation, center of mass deviation and the friction of the suspension shaft rotation on the unloading accuracy of the reflective surface during deployment. The test method is to use a push-pull force gauge to test the resistance of the reflective surface at different angles after the center of mass adjustment has been completed;

[0024] Further, in step B4, the counterweight calculation principle is to minimize the comprehensive influence of various interference factors on the additional moment of the root hinge of the reflection surface, and to establish a moment balance formula based on known parameters for configuration calculation;

[0025] Further, in step B5, fine-tuning the weight is to use a platform weighing device to fine-tune the weight to an accuracy of 0.1 kg;

[0026] In step B5, the weight calculation formula is:

[0027] The weight of the deployment test is: M+Δm1;

[0028] Δm1 calculation formula: 2Δm1gR sin 45°=2FR sin 45°+T2-T1;

[0029] The weight of the furling test is: M-Δm2;

[0030] Δm2 calculation formula: Δm2gR(sin 45°+1)=2FR+T1;

[0031] Wherein, M is the total mass of the reflecting surface, which is the measured value; Δm1 is the compensating mass for overcoming resistance during deployment; Δm2 is the compensating mass for overcoming resistance during folding; R is the distance from the hanging point to the root hinge; F is the hanging resistance of the air bearing; T1 is the maximum interference torque of the reflecting surface near the 45° deployment position; T2 is the maximum interference torque of the reflecting surface near the 135° deployment position.

[0032] Furthermore, the equipment for the deployment process of the reflecting surface includes a reflecting surface, a root hinge, a No. 1 lifting rope, a No. 2 lifting rope, a No. 1 pulley, a No. 2 pulley, a No. 1 follower trolley, a No. 2 follower trolley, a No. 3 pulley, a No. 4 pulley, a No. 1 counterweight and a No. 2 counterweight. The reflecting surface rotates around the root hinge, and both sides of the reflecting surface are respectively connected to one end of the No. 1 lifting rope and the No. 2 lifting rope, the other end of the No. 1 lifting rope passes through the No. 2 pulley and the No. 3 pulley in turn and is then connected to the No. 1 counterweight. The other end of the No. 2 lifting rope passes through the No. 1 pulley and the No. 4 pulley in turn and is then connected to the No. 2 counterweight. The No. 1 pulley and the No. 2 pulley are also respectively connected to the No. 2 follower trolley and the No. 1 follower trolley.

[0033] Furthermore, in step C1, adjusting the verticality of the suspension point refers to using an active following control system to adjust the position of the following trolley, and the verticality of the suspension rope can be measured by a theodolite or other instruments.

[0034] Furthermore, in step C2, system initialization means that the system records the position of the follower car at this time as the initial 0 position, and records the verticality of the suspension rope at this time, and adjusts the position of the follower car in real time with reference to the verticality during the subsequent deployment process.

[0035] Compared with the prior art, the large-scale flexible reflective surface gravity unloading accuracy control method of the present invention has the following advantages:

[0036] The large-scale flexible reflective surface gravity unloading accuracy control method described in the present invention can make the unloading accuracy meet the root hinge interference torque requirement of its deployment through the reduction of hanging interference force, system interference force compensation and active following of the reflective surface hanging point of this method. During the deployment process, it can also avoid the drift of the center of mass of the reflective surface and the instability of the unloading force, thereby improving the unloading accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0038] Figure 1 A schematic diagram of a control method according to an embodiment of the present invention;

[0039] Figure 2 A schematic diagram of a reflective surface unfolding process device according to an embodiment of the present invention;

[0040] Figure 3 This is a schematic diagram of a hanging resistance test according to an embodiment of the present invention;

[0041] Figure 4 This is a schematic diagram of a comprehensive resistance test of a reflective surface deployment process according to an embodiment of the present invention;

[0042] Figure 5A schematic diagram of a reflective surface unfolding process according to an embodiment of the present invention;

[0043] Figure 6 It is a schematic diagram of the process of folding the reflective surface according to an embodiment of the present invention.

[0044] Description of reference numerals:

[0045] 1. Reflection surface; 2. Root hinge; 3. Lifting rope No. 1; 4. Lifting rope No. 2; 5. Pulley No. 1; 6. Pulley No. 2; 7. Following trolley No. 1; 8. Following trolley No. 2; 9. Pulley No. 3; 10. Pulley No. 4; 11. Counterweight No. 1; 12. Counterweight No. 2. DETAILED DESCRIPTION

[0046] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0047] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and the like are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", and the like may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0048] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0049] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0050] like Figure 1 to Figure 2 As shown in the figure, the gravity unloading precision control method of large flexible reflective surface includes three parts: reduction of hanging interference force, system interference force compensation and active following of the hanging point of the reflective surface. The detailed flow chart is shown in the attached Figure 1 .

[0051] The methods to reduce the suspension interference force are: 1) the pulley adopts air flotation lubrication to reduce the pulley friction; 2) through the suspension resistance test, select the suspension rope with the least effect on the suspension resistance.

[0052] The method of interference force compensation is to measure the value of the system interference force, and then accurately calculate the mass of the compensation weight, so as to achieve the purpose of accurate passive compensation of the interference force. The process is: actual measurement of hanging resistance → adjustment of the center of mass of the reflective surface → actual measurement of the comprehensive resistance of the reflective surface during the expansion process → calculation of the weight → fine adjustment of the weight. The hanging resistance test can be directly tested with a push-pull force gauge, or indirectly tested with a small weight or a platform scale. The test process is shown in Figure 1 ; Adjusting the center of mass of the reflective surface is to use a counterweight to adjust the center of mass of the reflective surface to the center of the hanging shaft, so that the influence of the deviation of the center of mass of the reflective surface on the unloading accuracy is minimized. The adjustment method is that the reflective surface is in a suspended state, and the counterweight is used to adjust the reflective surface to a level in both horizontal and vertical states. An inclinometer can be used to measure whether it is adjusted to a level; The comprehensive resistance of the reflective surface during the unfolding process refers to the comprehensive influence of the flexible deformation of the reflective surface, the center of mass deviation and the friction of the hanging shaft rotation on the unloading accuracy during the unfolding process. The test method is to use a push-pull dynamometer to test the resistance of the reflective surface at different angles after the center of mass adjustment has been completed. The test process is attached Figure 1 ;; The counterweight calculation principle is to minimize the comprehensive influence of various interference factors on the additional torque of the root hinge of the reflection surface, and establish the torque balance formula according to the known parameters for configuration calculation; fine-tuning the counterweight means using high-precision weighing equipment such as a platform scale to fine-tune the counterweight to an accuracy of 0.1kg, further improving the accuracy of counterweight compensation.

[0053] The method of active following of the suspension point of the reflective surface is to use a servo motor to actively control the position of the suspension point so that the suspension rope always remains vertical. The control principle is: the real-time deflection angle of the suspension rope is used as the input information of the control system, the system converts the deflection angle of the suspension rope into the position information of the following suspension point, and the system controls the linear motion of the suspension point according to the deviation displacement of the suspension point. The process is: vertical adjustment of the suspension rope → system initialization → entering the following mode → start of the motor for unfolding the reflective surface → automatic following of the suspension point. Vertical adjustment of the suspension point refers to using the active following control system to adjust the position of the following trolley. The verticality of the suspension rope can be measured by a theodolite or other instruments; system initialization refers to the system recording the position of the following trolley at this time as the initial 0 position, and recording the verticality of the suspension rope at this time. In the subsequent unfolding process, the position of the following trolley is adjusted in real time with reference to the verticality; in the control strategy during the following process, the average filtering program, dead zone, and anti-rebound program are set to avoid the reverse following of the following trolley and suppress the vibration phenomenon during the unfolding process of the reflective surface.

[0054] The equipment composition of the reflector expansion process is shown in Figure 2As shown, the reflecting surface 1 rotates and unfolds around the root hinge 2, and the reflecting surface 1 is suspended and unloaded by the No. 1 lifting rope 3 and the No. 2 lifting rope 4. The No. 1 lifting rope 3 passes through the No. 2 pulley 6 and the No. 3 pulley 9 and is connected to the No. 1 counterweight 11; the No. 2 lifting rope 4 passes through the No. 1 pulley 5 and the No. 4 pulley 10 and is connected to the No. 2 counterweight 12; the No. 1 follower trolley 7 drives the No. 2 pulley 6 to move under the drive of the motor; the No. 2 follower trolley 8 drives the No. 1 pulley 5 to move under the drive of the motor; the No. 3 pulley 9 and the No. 4 pulley 10 are fixed.

[0055] Reflecting surface gravity unloading accuracy control process:

[0056] 1) Reduced hanging interference force

[0057] a. The first pulley 5, the second pulley 6, the third pulley 9 and the fourth pulley 10 adopt an air-floating lubrication structure;

[0058] b. After the hanging resistance test, the steel wire rope is selected as the hanging rope;

[0059] 2) Interference force compensation

[0060] a. Hanging resistance test: measure the resistance of the No. 1 hanging rope 3 and the No. 2 hanging rope 4 respectively, and record the measured values;

[0061] b. Adjust the centroid of reflective surface 1: Before the reflective surface 1 is installed on the supporting fixture, all equipment including cables required for the deployment process have been installed. In the suspended state, the reflective surface 1 is leveled in both horizontal and vertical states, and the levelness is measured using an inclinometer;

[0062] c. Comprehensive resistance test of reflective surface: After the center of mass of reflective surface 1 is adjusted, use a push-pull force gauge to measure the starting resistance of the reflective surface rotating around the hanging axis at the head and tail of the reflective surface. Measure a resistance value every 10°, calculate the torque value, and record the data;

[0063] d. Counterweight calculation: Based on the principle that the combined influence of all interference forces on the additional moment of the root hinge is minimized during the deployment process, a formula is established using known parameters to calculate the mass of the compensation counterweight;

[0064] Counterweight calculation formula:

[0065] 1) The weight of the unfolded test is: M+Δm1

[0066] Δm1 calculation formula: 2Δm1gR sin 45°=2FR sin 45°+T2-T1

[0067] 2) The weight of the folding test is: M-Δm2

[0068] Δm2 calculation formula: Δm2gR(sin 45°+1)=2FR+T1

[0069] in,

[0070] M—total mass of the reflecting surface, which is the measured value;

[0071] Δm1—compensation mass to overcome resistance during deployment;

[0072] Δm2—compensation mass to overcome resistance during the retraction process;

[0073] R--the distance from the hanging point to the root hinge;

[0074] F--air bearing hanging resistance;

[0075] T1--The maximum interference moment of the reflecting surface near the 45° position;

[0076] T2--The maximum interference torque of the reflecting surface near the 135° expansion position.

[0077] e. Fine-tune the counterweight: Use a large-range crane scale and a high-precision small-range platform scale to accurately adjust the counterweight with an accuracy of 0.1kg, and hang the counterweight (No. 1 counterweight 11, No. 2 counterweight 12) to the counterweight end of the lifting rope.

[0078] 3) Active following of the reflective surface hanging point

[0079] a. Adjust the verticality of the suspension rope: operate the control system interface and use the single-axis independent motion mode to control the positions of the two follower trolleys respectively, so that both suspension ropes are adjusted vertically. The verticality of the suspension ropes is measured using a theodolite with an accuracy of 1mm;

[0080] b. System initialization: operate the control system interface, initialize the system, define the current positions of the two follower cars as 0, and use the current verticality of the suspension rope as the theoretical verticality;

[0081] c. Enter the follow mode: operate the control system interface to enter the follow mode. At this time, the system will automatically follow when receiving a signal that the position of the hanging point has changed;

[0082] d. Start the reflective surface expansion motor: Start the reflective surface motor, the reflective surface begins to rotate around the root hinge and expand, and the position of the hanging point changes;

[0083] e. Automatic following of the lifting point: The system measurement system converts the measured lifting point position change information into the linear position deviation information of the following trolley, and feeds it back to the control system to control the servo motor to drive the following trolley to perform linear motion.

[0084] Example 1

[0085] like Figure 3-Figure 6 As shown, 1) a steel wire rope with a diameter of 3 mm is selected; the first pulley 5, the second pulley 6, the third pulley 9 and the fourth pulley 10 are all air-floating pulleys;

[0086] 2) Hanging resistance test: The weight is M1=M2=150kg. After testing, the resistance of both hanging ropes is 3N.

[0087] 3) Adjust the center of mass of the reflecting surface: The leveling accuracy in both horizontal and vertical directions is 0.1°. After leveling, the mass of the reflecting surface is 292.3kg. At this time, the distance from the hanging point to the root hinge is measured to be 1.74m.

[0088] 4) Test results of comprehensive resistance of reflective surface:

[0089] Table 1 Comprehensive resistance test results of the reflective surface deployment process

[0090]

[0091]

[0092] 5) Calculation of unloading counterweight: According to the formula, the counterweights of the two hanging poles are: the theoretical value of the counterweight for the unfolded test is 146.3kg, and the theoretical value of the counterweight for the retracted test is 145.8kg.

[0093] 6) Adjust the counterweight: According to the calculation results, adjust the unloading counterweight of each hanging to 145.8kg, that is, the folded test counterweight; when deploying, place a compensating counterweight of 0.5Kg on the folded counterweight, that is, adjust it to the deployed test counterweight.

[0094] 7) Uninstallation results:

[0095] According to the results of the deployment test, the maximum additional torque of the root hinge of the reflector surface during the deployment process is 15Nm, and the unloading accuracy is calculated to be 3‰.

[0096] It should be noted that Figure 5-Figure 6 It is the additional moment curve of the root hinge, the vertical axis is in Nm, and the horizontal axis is the unfolding angle in degrees.

[0097] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for controlling the gravity unloading accuracy of a large flexible reflective surface, characterized in that: It includes a method for reducing the suspension interference force, a method for compensating the system interference force and a method for actively following the reflective surface suspension point, which are executed in sequence; The method for reducing the suspension interference force comprises the following steps: A1. The pulley adopts air flotation lubrication to reduce the friction of the pulley; A2. Select the rope with the least influence on the hanging resistance through the hanging resistance test; System disturbance force compensation methods include: B1. Hanging resistance test; B2, adjusting the centroid of the reflecting surface; B3. Expand the reflective surface through the reflective surface expansion process equipment, and measure the comprehensive resistance of the reflective surface expansion process; B4. Counterweight calculation; B5. Fine-tune the weight; The active following method of the reflective surface hanging point includes the following steps: C1. Adjust the suspension rope vertically; C2, system initialization; C3, enter follow mode; C4, the reflective surface unfolding motor starts; C5, the hanging point automatically follows.

2. The method for controlling the gravity unloading accuracy of a large flexible reflective surface according to claim 1, characterized in that: In step B1, the hanging resistance test is performed using a push-pull force gauge test or an indirect test using a bench scale.

3. The method for controlling the gravity unloading accuracy of a large flexible reflective surface according to claim 1, characterized in that: In step B2, the center of mass of the reflecting surface is adjusted by using a counterweight to adjust the center of mass of the reflecting surface to the center of the hanging axis, so that the influence of the center of mass deviation of the reflecting surface on the unloading accuracy is minimized. The adjustment method is that when the reflecting surface is in a suspended state, a counterweight is used to adjust the reflecting surface to be level in both horizontal and vertical states, and an inclinometer is used to measure whether it is adjusted to be level.

4. The large-scale flexible reflective surface gravity unloading accuracy control method according to claim 1 is characterized in that: In step B3, the comprehensive resistance of the reflective surface during the deployment process refers to the comprehensive influence of the flexible deformation, center of mass deviation and friction of the suspension shaft rotation on the unloading accuracy of the reflective surface during the deployment process. The test method is to use a push-pull force gauge to test the resistance of the reflective surface at different angles after the center of mass adjustment has been completed.

5. The large-scale flexible reflective surface gravity unloading accuracy control method according to claim 1 is characterized in that: In step B4, the counterweight calculation principle is to minimize the comprehensive influence of various interference factors on the additional torque of the root hinge of the reflection surface, and to establish a torque balance formula based on known parameters for configuration calculation.

6. The large-scale flexible reflective surface gravity unloading accuracy control method according to claim 1 is characterized in that: In step B5, the weight is finely adjusted by using a platform weighing device to a precision of 0.1 kg; In step B5, the weight calculation formula is: The weight of the deployment test is: M+Δm1; Δm1 calculation formula: 2Δm1gR sin 45°=2FR sin 45°+T2-T1; The weight of the furling test is: M-Δm2; Δm2 calculation formula: Δm2gR(sin 45°+1)=2FR+T1; Wherein, M is the total mass of the reflecting surface, which is the measured value; Δm1 is the compensating mass for overcoming resistance during deployment; Δm2 is the compensating mass for overcoming resistance during folding; R is the distance from the hanging point to the root hinge; F is the hanging resistance of the air bearing; T1 is the maximum interference torque of the reflecting surface near the 45° deployment position; T2 is the maximum interference torque of the reflecting surface near the 135° deployment position.

7. The method for controlling the gravity unloading accuracy of a large flexible reflective surface according to claim 1, characterized in that: The equipment for the deployment process of the reflecting surface includes a reflecting surface, a root hinge, a No. 1 lifting rope, a No. 2 lifting rope, a No. 1 pulley, a No. 2 pulley, a No. 1 follower trolley, a No. 2 follower trolley, a No. 3 pulley, a No. 4 pulley, a No. 1 counterweight and a No. 2 counterweight. The reflecting surface rotates around the root hinge, and both sides of the reflecting surface are respectively connected to one end of the No. 1 lifting rope and the No. 2 lifting rope, and the other end of the No. 1 lifting rope passes through the No. 2 pulley and the No. 3 pulley in turn and is then connected to the No. 1 counterweight. The other end of the No. 2 lifting rope passes through the No. 1 pulley and the No. 4 pulley in turn and is then connected to the No. 2 counterweight. The No. 1 pulley and the No. 2 pulley are also respectively connected to the No. 2 follower trolley and the No. 1 follower trolley.

8. The method for controlling the gravity unloading accuracy of a large flexible reflective surface according to claim 1, characterized in that: In step C1, adjusting the verticality of the suspension point means using an active following control system to adjust the position of the following trolley, and the verticality of the suspension rope can be measured by a theodolite or other instruments.

9. The method for controlling the gravity unloading accuracy of a large flexible reflective surface according to claim 1, characterized in that: In step C2, system initialization means that the system records the position of the following car at this time as the initial 0 position, and records the verticality of the suspension rope at this time, and adjusts the position of the following car in real time with reference to the verticality during the subsequent deployment process.

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