Moment output characteristic measuring device and testing method for control moment gyro

Abstract

The invention discloses a moment output characteristic measuring device and testing method for a control moment gyro, and belongs to the technical field of aircraft control and ground simulation. The objective of the invention is to realize high-precision torque measurement. The device is composed of an ultra-static suspension system, a precise torque sensitive system, a high-precision torque calibration system and a data monitoring and control system. The ultra-static suspension system comprises an air floating ball bearing, an instrument mounting platform and a supporting and unloading device, the air floating ball bearing is arranged in an air floating ball bowl, the air floating ball bearing is fixedly connected with the instrument mounting platform through a bolt, tested equipment is placed on the air floating ball bearing, and a pressure sensor is mounted on the supporting and unloading device; the precise torque sensing system is composed of a horizontal torque measuring system and a vertical torque measuring system. The high-precision torque calibration system is composed of an inertial navigation unit and a single-axis mass adjusting robot, and the data monitoring and control system is connected with the ultra-static suspension system, the precise torque sensitive system and the high-precision torque calibration system through a wireless communication device.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of aircraft control and ground simulation, and particularly relates to a control moment gyro moment output characteristic measuring device and a testing method. BACKGROUND

[0002] The control moment gyro is an important attitude actuator in a spacecraft, and has been widely used in the field of aerospace. A high-precision control moment gyro output moment measuring method is needed to test the output characteristic of the control moment gyro in view of the problem of fuzzy output characteristic.

[0003] The invention patent "torque test air floating turntable for control moment gyro" (CN200610011829.7) measures the output moment of the control moment gyro through a single-shaft air floating turntable, and is divided into two working modes, namely a free rotation mode and a torque rebalancing mode. The free rotation mode uses an encoder to calculate the turntable main shaft speed so as to obtain the output moment of the control moment gyro in the direction of the air floating turntable rotating shaft. The torque rebalancing mode forms a torque loop on the basis of high-precision position closed loop, and realizes high-precision measurement of the torque in the direction of the air floating turntable rotating shaft through the torque loop. However, the output moment in the direction of the air floating turntable rotating shaft can only be measured, and the complete output moment characteristic of the control moment gyro cannot be obtained. Meanwhile, the measuring device is not calibrated before measurement, the control moment calculated according to the program is the nominal value of the measurement, and is not the real output moment. Meanwhile, the measuring system may contain unmodeled characteristics, which will cause obvious difference between the output moment precision and the actual output moment.

[0004] The invention patent "high-precision control moment gyro torque output measuring device and measuring method thereof" (CN201610191170.1) adopts a double-shaft air floating table as a measuring platform. In the process of measuring the torque, the device uses the force sensor data collected by three torque measuring mechanisms, cooperates with the distance from the force sensor to the center of the air floating ball bearing, and calculates the output moment and torque fluctuation of the control moment gyro. However, the influence of the inclination of the air floating table and the error of the force arm measurement in the measuring process is not considered, the output moment precision cannot be guaranteed, and the calibration of the measuring device is also lacked, so that the authenticity of the measurement result is difficult to guarantee. Meanwhile, due to the layout problem of the measuring sensor, the device can only measure the horizontal output moment, and cannot measure the vertical moment, so that the device is not applicable to the output characteristic test of all control moment gyro. SUMMARY

[0005] The problem to be solved by the application is to realize high-precision torque measurement, and a control moment gyro torque output characteristic measuring device and a testing method are provided.

[0006] To achieve the above object, the application realizes the following technical scheme:

[0007] A control moment gyro torque output characteristic measuring device, comprising an ultra-static suspension system, a precise torque sensitive system, a high-precision torque calibration system and a data monitoring and control system;

[0008] The ultra-static suspension system comprises an air-floating ball bearing, an instrument installation platform and a support unloading device, the air-floating ball bearing is arranged in an air-floating ball bowl, the air-floating ball bearing is tightly connected with the instrument installation platform, the instrument installation platform is used for placing a measured device, and the support unloading device is provided with a pressure sensor;

[0009] The precise torque sensitive system is composed of a horizontal torque measurement system and a vertical torque measurement system;

[0010] Four groups of horizontal torque measurement systems are uniformly arranged on the instrument installation platform at an angle of 90°, and are used for converting horizontal torque measurement into force measurement; the vertical torque measurement system comprises a high-precision force sensor group, an air-floating bearing and an auxiliary extension mechanism, the auxiliary extension mechanism is rigidly connected with the instrument installation platform; the high-precision force sensor group is composed of two force sensors, and is installed outside two air-floating surfaces formed between the air-floating bearing and the auxiliary extension mechanism, and is used for realizing z-axis torque measurement and decoupling z-axis torque from xy-axis torque measurement;

[0011] The high-precision torque calibration system is placed on the instrument installation platform, and comprises an inertial navigation unit and a single-axis mass adjustment robot, the number of the single-axis mass adjustment robots is two, and the single-axis mass adjustment robots are orthogonally distributed between the measured device and the horizontal torque measurement system, and are used for realizing instrument installation platform leveling work while outputting high-precision standard torque; the inertial navigation unit is placed between the measured device and the horizontal torque measurement system and faces the single-axis mass adjustment robot, and is used for monitoring the attitude information of the ultra-static suspension system in real time;

[0012] The data monitoring and control system is connected with the ultra-static suspension system, the precise torque sensitive system and the high-precision torque calibration system through a wireless communication device.

[0013] Further, the horizontal torque measurement system comprises a micro-touch unit, a high-precision force sensor, a high-precision electric linear push rod, an air cushion, a pneumatic actuating rod, a pneumatic pre-tightening unit, a composite cross beam, an air-floating guide rail and an air-floating sliding block.

[0014] The composite cross beam is fixed on the air floating guide rail, the high-precision electric linear push rod is rigidly connected with the air floating slide block through the composite cross beam, the pneumatic actuator rod penetrates the air-tight cavity of the composite cross beam and acts on the upper surface of the air floating slide block, the pneumatic pre-tightening unit is integrated in the pneumatic actuator rod and is independently controlled through the air pressure pipeline, the output end of the pneumatic pre-tightening unit is coupled with the air floating slide block, the air floating slide block is suspendedly installed in the rolling way of the air floating guide rail, the lower surface of the air floating slide block is fixedly connected with the high-precision force sensor, the micro-touch unit is connected with the measuring end of the high-precision force sensor, the high-precision electric linear push rod pre-presses the micro-touch unit on the air cushion placed on the instrument installation platform through the high-precision force sensor, and the locking effect of the pneumatic pre-tightening unit is matched, so that the high-precision force sensor and the instrument installation platform are pre-pressed tightly.

[0015] Further, the supporting and unloading devices are three groups in total and are distributed at 120° for supporting and roughly leveling the instrument installation platform, and the two single-axis mass adjustment robots are robot A and robot B.

[0016] Further, the data monitoring and control system is responsible for receiving the output information of the sensitive elements and control elements in each system, sending the mass adjustment and loading instructions to the high-precision torque compensation system and the precise torque sensitive system, and calculating the compensation information and the measured torque.

[0017] Further, the measured force results of the four groups of horizontal torque measurement systems are F1, F2, F3 and F4 respectively, the theoretical force arms between each force sensor and the rotation center are L1, L2, L3 and L4 respectively, the measured force results of the vertical torque measurement system are F5 and F6 respectively, the theoretical force arms between each force sensor and the rotation center are L5 and L6 respectively, and the output torque formula under the ideal condition is obtained according to the balance method for measuring torque as follows:

[0018]

[0019] Wherein, , and are the measured torque results in the x direction, the y direction and the z direction respectively.

[0020] A control torque gyro torque output characteristic measurement method, relying on the control torque gyro torque output characteristic measurement device, comprising the following steps:

[0021] S1. Confirm whether the air floating ball bearing is ventilated, whether the power supply of the control torque gyro torque output characteristic measurement device is turned on, and enter the working state after the air floating ball bearing is ventilated and the power supply is turned on;

[0022] S2. Artificially increase the load weight on the instrument installation platform, read the pressure sensor value on the support unloading device, and complete the coarse trimming of the control moment gyro torque output characteristic measuring device when the pressure sensor values are substantially equal;

[0023] S3. Remove the support unloading device, then use the inertial navigation unit as feedback to control the motion of the programmed mass adjustment assembly in the single-axis mass adjustment robot, and complete the fine trimming of the control moment gyro torque output characteristic measuring device when the inertial navigation unit shows that the instrument installation platform attitude reaches the predetermined level requirement;

[0024] S4. Complete the self-calibration of the high-precision torque calibration system based on the high-precision standard torque self-calibration method, and obtain the high-precision standard torque;

[0025] S5. Based on the high-precision standard torque measuring system self-correction method, load the precision torque sensitive system, complete the self-correction of the control moment gyro torque output characteristic measuring device, and obtain the predictive neural network model and z-axis error compensation relationship model;

[0026] S6. Adjust the control moment gyro torque output characteristic measuring device to be in the self-correction initial state, turn on the measured device, perform torque measurement, calculate the output torque of the measured device based on the predictive neural network model and z-axis error compensation relationship model and the output torque formula, save the experimental data, and complete the experiment.

[0027] Further, the specific implementation method of the high-precision standard torque self-calibration method in step S4 includes the following steps:

[0028] S4.1. Based on the fine trimming condition of the control moment gyro torque output characteristic measuring device, set the position code of the known mass load on the instrument installation platform , ;

[0029] S4.2. Without loading the precision torque sensitive system, read the inertial navigation unit data through the data monitoring and control system and control the programmed mass adjustment assembly in the robot A and the robot B to move, so as to realize the horizontal leveling of the super static suspension system;

[0030] S4.3. Add a known mass load on the instrument installation platform, and the mass load is installed at position P1. Level the super static suspension system again, record the measurement system state at this time as the initial zero position state of the self-calibration, and record the mass of the mass load and the position of the programmed mass adjustment assembly in the robot A and the robot B at this time;

[0031] S4.4. According to the position code Move the mass load in ascending order, and after each movement of the mass load, repeat the horizontal leveling work of the super-static suspension system, and record the relative displacement of each movement of the mass load And the relative displacement of each horizontal leveling movement of the programmed mass adjustment assembly in robot A and robot B And Where i represents the number of times the mass load is moved, and N sets of data are obtained

[0032] S4.5. Define the unknown quantities, including the total mass of the programmed mass adjustment assembly in robot A and robot B, respectively And The installation error angle between robot A and the x-axis The installation error angle between robot B and the y-axis The high-precision standard torque self-calibration calculation method is constructed as follows

[0033] S4.5.1. Construct a least squares system, and construct a linear equation group based on N sets of measurement numbers as follows

[0034]

[0035] Define the variables to be solved as ;

[0036] S4.5.2. Solve the intermediate variables based on the improved total least squares method: denote the coefficient matrix as , the observation vector as , construct the augmented matrix and perform SVD singular value decomposition as follows

[0037]

[0038] Where the coefficient matrix , the observation vector , is the singular value matrix, is the left singular value vector matrix

[0039] Let the last column of be and correct it to , where is the regularization parameter, then the above variables to be solved are written as:

[0040] ;

[0041] S4.5.3. Calculate the mass of the programmed mass adjustment assembly, and obtain:

[0042] ;

[0043] S4.5.4. Separating the angle parameter, and solving the final error installation angle according to N groups of data, we get:

[0044]

[0045] ;

[0046] S4.5.5. After the above self-calibration, the high-precision standard torque self-calibration output formula is as follows:

[0047]

[0048] wherein, is the x-axis high-precision standard torque, is the y-axis high-precision standard torque, and are the relative positions of the program-controlled mass adjustment components of the two robots.

[0049] Further, the specific implementation method of the high-precision standard torque measurement system self-correction method in step S5 includes the following steps:

[0050] S5.1. Construct a neural network prediction model for horizontal torque self-correction, the neural network prediction model adopts the structure of input layer-2 hidden layers-output layer, the input layer is the output information of the force sensor and the inertial navigation unit, including a 7-dimensional input vector and , is the three-axis attitude data output by the inertial navigation unit, the output layer is the horizontal torque of the x-axis and the y-axis, and the two hidden layers are composed of 10 neurons and 5 neurons respectively;

[0051] S5.2. The vertical torque self-correction method is to obtain the z-axis error compensation relationship model by polynomial fitting; based on and solving the z-axis disturbance torque, the calculation formula is as follows:

[0052]

[0053] wherein, is the z-axis disturbance torque, and are the nominal force arms corresponding to and respectively.

[0054] The mapping relationship between the attitude angle and the disturbance torque is established , the expression is:

[0055]

[0056] wherein k is the data sample index, N is the total number of data samples, is the x-axis attitude data, y-axis attitude data, z-axis attitude data of the kth sample, is the interference torque around the z-axis corresponding to the kth sample;

[0057] A polynomial regression is performed on the mapping relationship between the attitude angle and the interference torque, and a z-axis error compensation relationship model is generated as follows:

[0058]

[0059] wherein, is the z-axis compensation torque, is a polynomial base function, , is a fitting coefficient, j is the term number index of the polynomial base function, m is the highest order number of the polynomial regression, and the construction of the z-axis error compensation relationship model realizes self-correction of the vertical torque.

[0060] Further, the self-correction method of the control moment gyro torque output characteristic measuring device is completed by loading the precision torque sensitive system in step S5.

[0061] Before formal measurement of the measured device, first of all, the super static suspension system is also ensured to be in the leveling state, then the precision torque sensitive system is loaded to the instrument installation platform, and each force sensor output is set to 50% of the full scale, so as to obtain a self-correction initial state of the control moment gyro torque output characteristic measuring device.

[0062] Then, the data monitoring and control system sends a programmed torque sequence to the single-axis mass adjustment robot in the high-precision torque calibration system, and the single-axis mass adjustment robot outputs high-precision programmed torque by changing the relative position of the programmed mass adjustment assembly according to the self-calibration result.

[0063] Then, the high-precision programmed torque, the force sensor and the output information of the inertial navigation unit are stored in real time and synchronously, and the high-precision standard torque measurement system is used to perform self-correction operation on the horizontal torque and the vertical torque respectively.

[0064] After the self-correction is completed, the measurement system and the model are used to realize high-precision torque measurement.

[0065] The beneficial effects of the present application are as follows:

[0066] The control moment gyro torque output characteristic measuring device provided by the application can obtain high-precision output torque by using the measuring system itself without introducing high-precision torque output equipment, and the high-precision output torque is low in cost and simple in calibration method; the measuring system can be self-corrected according to the high-precision output torque without additional output torque correction equipment.

[0067] The control moment gyro torque output characteristic measuring device provided by the application can obtain high-precision output torque by using the measuring system itself without introducing high-precision torque output equipment, and the high-precision output torque is low in cost and simple in calibration method; the measuring system can be self-corrected according to the high-precision output torque without additional output torque correction equipment.

[0068] The control moment gyro torque output characteristic measuring device provided by the application can realize three-axis torque measurement and high-precision measurement of output torque of all structure control moment gyro. BRIEF DESCRIPTION OF DRAWINGS

[0069] Figure 1 The figure is a structural schematic diagram of the control moment gyro torque output characteristic measuring device provided by the application;

[0070] Figure 2 The figure is a top view of the control moment gyro torque output characteristic measuring device provided by the application;

[0071] Figure 3 The figure is a structural schematic diagram of the vertical torque measuring system provided by the application;

[0072] Figure 4 The figure is a structural schematic diagram of the horizontal torque measuring system provided by the application;

[0073] Figure 5 The figure is a structural schematic diagram of the single-axis mass adjustment machine provided by the application;

[0074] Figure 6 The figure is a mass load installation position diagram provided by the application;

[0075] Figure 7 The figure is a flow chart of the high-precision standard torque measuring system self-correction method provided by the application;

[0076] Figure 8 The figure is a flow chart of the control moment gyro torque output characteristic measuring method provided by the application. DETAILED DESCRIPTION

[0077] In order to make the objects, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application, i.e., the specific embodiments described are only a part of the embodiments of the present application, but not all the specific embodiments. The components of the specific embodiments of the present application generally described and shown in the accompanying drawings can be arranged and designed in various different configurations, and the present application can also have other embodiments.

[0078] Therefore, the following detailed description of the specific embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the claimed present application, but only represents selected specific embodiments of the present application. Based on the specific embodiments of the present application, all other specific embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0079] In order to further understand the inventive content, characteristics and effects of the present application, the following specific embodiments are exemplified, and the accompanying drawings are used for the description. Figure 1 - the accompanying drawings Figure 8 The detailed description is as follows:

[0080] Example 1:

[0081] A control moment gyro torque output characteristic measuring device, comprising an ultra-static suspension system, a precise torque sensitive system, a high-precision torque calibration system and a data monitoring and control system;

[0082] The ultra-static suspension system comprises an air-floating ball bearing 1, an instrument installation platform 2 and a support unloading device 17, the air-floating ball bearing 1 is arranged in an air-floating ball bowl 3, the air-floating ball bearing 1 is tightly connected with the instrument installation platform 2, the measured equipment 16 is placed on the instrument installation platform 2, and the pressure sensor 18 is installed on the support unloading device 17;

[0083] The precise torque sensitive system is composed of a horizontal torque measuring system 20 and a vertical torque measuring system 21;

[0084] 4 groups of horizontal torque measuring systems 20 are uniformly arranged on the instrument installation platform 2 at 90°, for converting horizontal torque measurement into force measurement; the vertical torque measuring system 21 comprises a high-precision force sensor group 22, an air-floating bearing 23 and an auxiliary extension mechanism 25, the auxiliary extension mechanism 25 is rigidly connected with the instrument installation platform 2; the high-precision force sensor group 22 is composed of two force sensors, the high-precision force sensor group 22 is installed outside two air-floating surfaces 24 formed between the air-floating bearing 23 and the auxiliary extension mechanism 25, for realizing z-axis torque measurement and decoupling z-axis torque from xy-axis torque measurement;

[0085] The high-precision torque calibration system is placed on the instrument installation platform 2, and includes an inertial navigation unit 13 and single-axis mass adjustment robots 14. The number of the single-axis mass adjustment robots 14 is two, and the single-axis mass adjustment robots 14 are orthogonally distributed between the measured device 16 and the horizontal torque measurement system 20, that is, on the side of the negative direction of the torque axis x. The attitude output axis of the inertial navigation unit 13 coincides with the torque measurement axis of the measurement system, so as to realize the leveling of the instrument installation platform 2 and output the high-precision standard torque at the same time. The inertial navigation unit 13 faces the single-axis mass adjustment robots 14 and is placed between the measured device 16 and the horizontal torque measurement system 20, so as to monitor the attitude information of the super-static suspension system in real time.

[0086] The data monitoring and control system 15 is connected with the super-static suspension system, the precise torque sensitive system and the high-precision torque calibration system through wireless communication devices.

[0087] Further, the horizontal torque measurement system 20 includes a micro-touch unit 4, a high-precision force sensor 5, a high-precision electric linear push rod 6, an air cushion 7, a pneumatic actuator rod 8, a pneumatic pre-tightening unit 9, a composite cross beam 10, an air floating guide rail 11 and an air floating slider 12.

[0088] The composite cross beam 10 is fixedly installed on the air floating guide rail 11. The high-precision electric linear push rod 6 is rigidly connected with the air floating slider 12 through the composite cross beam 10. The pneumatic actuator rod 8 penetrates the air-tight cavity of the composite cross beam 10 and acts on the upper surface of the air floating slider 12. The pneumatic pre-tightening unit 9 is integrated in the pneumatic actuator rod 8 and is independently controlled through the air pressure pipeline. The output end of the pneumatic pre-tightening unit 9 is coupled with the air floating slider 12. The air floating slider 12 is suspendedly installed in the rolling track of the air floating guide rail 11. The lower surface of the air floating slider 12 is fixedly connected with the high-precision force sensor 5. The micro-touch unit 4 is connected with the measurement end of the high-precision force sensor 5. The high-precision electric linear push rod 6 pre-presses the micro-touch unit 4 on the air cushion 7 placed on the instrument installation platform 2 through the high-precision force sensor 5. In cooperation with the locking action of the pneumatic pre-tightening unit 9, the high-precision force sensor 5 and the instrument installation platform 2 are pre-pressed tightly.

[0089] Further, the support unloading device 17 has three groups and is distributed at an angle of 120°, and is used for supporting and roughly leveling the instrument installation platform 2. The two single-axis mass adjustment robots 14 are robot A and robot B respectively.

[0090] Further, the data monitoring and control system 15 is responsible for receiving the output information of the sensitive elements and control elements in each system, sending the mass adjustment and loading instructions to the high-precision torque compensation system and the precise torque sensitive system, and calculating the compensation information and the measured torque at the same time.

[0091] Further, the measured force results of the 4 groups of horizontal moment measuring systems 20 are F1, F2, F3, and F4 respectively, the theoretical force arms between each force sensor and the rotation center are L1, L2, L3, and L4 respectively, the measured force results of the vertical moment measuring system 21 are F5 and F6 respectively, and the theoretical force arms between each force sensor and the rotation center are L5 and L6 respectively. According to the balance method of force moment, the output moment formula under the ideal condition is:

[0092]

[0093] wherein, , and are the measured moment results in the x direction, the y direction, and the z direction respectively.

[0094] Further, a high-pressure gas film is formed between the air-floating ball bowl and the air-floating ball bearing. When no platform constraint is applied, the air-floating ball bearing can construct a micro-friction and micro-interference environment to drive the instrument installation platform to realize three-axis free rotation. The instrument installation platform is made of high-strength structural steel, and has standard mounting holes and positioning holes processed by a high-precision numerical control machine tool, which facilitates the installation of the measured equipment 16 and the system equipment. The support unloading device can support the instrument installation platform in a non-working state to prevent it from overturning, and the pressure sensor 18 on the support unloading device can be used to guide the rough leveling.

[0095] Further, the high-precision force sensor group in the vertical moment measuring system is installed on the air-floating bearing, and the two parts are connected by the air-floating surface as a force transmission structure. This design not only adapts to the small movement of the air-floating table itself in the xy axis, but also ensures the decoupling of the z-axis moment measurement and the xy-axis moment measurement. The force sensor adopts a paired installation mode, and two force sensors are selected to form a sensor group, which are denoted as force sensor A and force sensor B. In order to reduce the force transmission error caused by poor contact, the force sensor also adopts a preloading mode, so that the force sensor and the auxiliary extension mechanism are in close contact through the air-floating surface. When the air-floating table generates a z-axis rotation trend due to the z-axis moment output by the control moment gyro (CMG), the two force sensors on the z-axis simultaneously sense the force, and the corresponding force arm information can be combined to differentially calculate the z-axis moment.

[0096] Further, the high-precision moment calibration system is installed on the x-axis and is called robot A, and is installed on the y-axis and is called robot B. It can realize the leveling work of the instrument installation platform, and also can output high-precision standard moment , realize output torque measurement system self-correction. Among them, the inertial unit selects HG-120 type inertial combination, single-axis mass adjustment robot selects HIWIN single-axis robot. The standard torque can be realized by the single-axis mass adjustment robot 14 in the high-precision torque calibration system, and the single-axis mass adjustment robot program control mass adjustment component is composed of a mobile load 14-1 and a bearing slider 14-2.

[0097] Further, when the measured CMG is installed on the instrument installation platform that has been leveled and outputs torque, the super static suspension system will have a corresponding movement trend under the pre-tightening effect of the precision torque sensitive system, at this time the force sensor in the precision torque sensitive system will output the corresponding force data under the current torque.

[0098] Embodiment 2:

[0099] A control torque gyro torque output characteristic measurement method, relying on the control torque gyro torque output characteristic measurement device of embodiment 1, comprising the following steps:

[0100] S1. Confirm whether the air floating ball bearing is ventilated, whether the power supply of a control torque gyro torque output characteristic measurement device is turned on, and enter the working state after the air floating ball bearing is ventilated and the power supply is turned on;

[0101] S2. Artificially increase the load weight on the instrument installation platform, read the pressure sensor value on the support unloading device, when the pressure sensor value is basically equal, complete the rough leveling of a control torque gyro torque output characteristic measurement device;

[0102] S3. Remove the support unloading device, then take the inertial unit as the feedback, control the motion of the program control mass adjustment component in the single-axis mass adjustment robot, when the inertial unit displays that the instrument installation platform attitude reaches the predetermined level requirement, complete the fine leveling of a control torque gyro torque output characteristic measurement device;

[0103] S4. Based on the high-precision standard torque self-calibration method, complete the high-precision torque calibration system self-calibration, and obtain the high-precision standard torque;

[0104] In actual use of the system to measure the output torque, on the one hand, due to the non-completely rigid force sensor, when the output torque acts on the measuring platform, the measuring platform will produce deflection due to the torque, at this time the measuring system will introduce the influence of gravity torque, thereby causing the output torque precision to decline; on the other hand, the actual force arm information may be different from the design value, which also causes the output torque measurement precision to decline. To solve the above precision influencing factors, it is necessary to use a standard torque calibration measurement system. When the data monitoring and control system sends a mass adjustment instruction to the single-axis mass adjustment robot, the program-controlled mass adjustment assembly changes the distance between itself and the rotation center of the super-static suspension system by moving to realize the program-controlled torque output. However, the program-controlled torque output by this method has an error compared with the ideal standard torque. The error is derived from two aspects: one is the unknown error angle between the moving direction of the program-controlled mass adjustment assembly on the single-axis mass adjustment robot and the actual installation direction, and the other is the unknown mass characteristics of the bearing slider.

[0105] Further, the specific implementation method of the high-precision standard torque self-calibration method in step S4 includes the following steps:

[0106] S4.1. Based on the precision alignment condition of a control torque gyro torque output characteristic measuring device, set the position code of the known mass load on the instrument installation platform , ;

[0107] S4.2. Without loading the precision torque sensitive system, read the inertial navigation unit data through the data monitoring and control system and control the movement of the program-controlled mass adjustment assembly in the robot A and the robot B to realize the horizontal leveling of the super-static suspension system;

[0108] S4.3. Add a known mass load on the instrument installation platform, and install the mass load at position P1. Level the super-static suspension system again, record the measurement system state at this time as the initial zero position state of the self-calibration, and record the mass load mass and the position of the program-controlled mass adjustment assembly in the robot A and the robot B;

[0109] S4.4. Move the mass load in ascending order according to the position code , and after each movement of the mass load, repeat the horizontal leveling work of the super-static suspension system, record the relative displacement of the mass load each time and the relative displacement of the program-controlled mass adjustment assembly in the robot A and the robot B after horizontal leveling each time and , wherein i represents the number of mass load movements, and N sets of data are obtained;

[0110] S4.5. Define unknown quantities including total mass of the program-controlled mass adjustment assembly in robot A and robot B, respectively as and , the installation error angle between robot A and x-axis , the installation error angle between robot B and y-axis , the construction of high-precision standard torque self-calibration calculation method is as follows:

[0111] S4.5.1. Construct the least squares system, construct the linear equation group based on N groups of measurement numbers as follows:

[0112]

[0113] Define the variables to be solved as ;

[0114] S4.5.2. Solve the intermediate variables based on the improved total least squares method: denote the coefficient matrix as , the observation vector as , construct the augmented matrix and perform SVD singular value decomposition as follows:

[0115]

[0116] Wherein, the coefficient matrix , the observation vector , is the singular value matrix, is the left singular value vector matrix;

[0117] Let the last column of be and correct it to , wherein is the regularization parameter, then the above to-be-solved variables are written as:

[0118] ;

[0119] S4.5.3. Calculate the mass of the program-controlled mass adjustment assembly, get:

[0120] ;

[0121] S4.5.4. Separate the angle parameters, and solve the final error installation angle according to N groups of data, get:

[0122]

[0123] ;

[0124] S4.5.5. After the above self-calibration, the high-precision standard torque self-calibration output formula is as follows:

[0125]

[0126] wherein, is the x-axis high-precision standard torque, is the y-axis high-precision standard torque, and are the relative positions of the program-controlled mass adjustment assembly of the two robots, respectively.

[0127] S5. A measurement system self-correction method based on high-precision standard torque, loading a precision torque sensitive system, completing the self-correction of a torque output characteristic measurement device of a control torque gyro, obtaining a predictive neural network model and a z-axis error compensation relationship model;

[0128] After obtaining the above high-precision standard torque, before formally measuring the output torque of the measured device, a measurement system self-correction method based on high-precision standard torque is invented to realize measurement system self-correction, to solve the influence of the above-mentioned table tilt introduced gravity torque, force arm change and other unknown errors on horizontal torque measurement, so as to truly realize high-precision measurement of output torque. The setting method is as follows:

[0129] Before formally measuring the measured device, first of all, also ensure that the super static suspension system is in the leveling state, then load the precision torque sensitive system to the instrument installation platform, and make each force sensor output 50% of the full scale through the pre-tightening device, at this time it is considered as the initial state of the measurement system self-correction. Then, the data monitoring and control system sends a program-controlled torque sequence to the single-axis mass adjustment robot in the high-precision torque calibration system, and the single-axis mass adjustment robot outputs high-precision program-controlled torque by changing the relative position of the program-controlled mass adjustment assembly according to the self-calibration result. After that, considering the accuracy of the calibration process, the program-controlled torque sequence contains multiple static calibration points and dynamic composite calibration points. According to the above two torque sequences, the process of outputting high-precision program-controlled torque is divided into two stages: multi-stage static torque output and dynamic composite torque output:

[0130] When multi-stage static torque output, step torque is independently applied on x-axis and y-axis in turn (sequence: 0→10%FS→…→100%FS→…→0 symmetric increasing and decreasing sequence, each step has a predetermined time length);

[0131] When dynamic composite torque output, parameter-adjustable sinusoidal torque is independently applied on x-axis and y-axis in turn Wherein, A is the amplitude, f is the frequency, φ is the phase, B is the bias, the torque adopts the form of scanning frequency first and then scanning amplitude. In the scanning frequency stage, the amplitude A is fixed, and the frequency f is gradually increased from low frequency to the bandwidth of the measurement system. After the scanning frequency is completed, the scanning amplitude stage is entered, the frequency f is fixed, and the amplitude A is changed in steps. In the above process, the parameters can be configured as needed.

[0132] In the above output high-precision program-controlled torque process, the output information of the high-precision program-controlled torque, the force sensor and the inertial navigation unit is stored in real time and synchronously, and the horizontal torque and the vertical torque are respectively subjected to self-correction operation.

[0133] Further, the specific implementation method of the self-correction method of the high-precision standard torque measurement system in step S5 includes the following steps:

[0134] S5.1. Construct a neural network prediction model for horizontal torque self-correction, the neural network prediction model adopts the structure of input layer-2 hidden layers-output layer, the input layer is the output information of the force sensor and the inertial navigation unit, including a 7-dimensional input vector and , is the three-axis attitude data output by the inertial navigation unit, the output layer is the horizontal torque of the x-axis and the y-axis, and the two hidden layers are respectively composed of 10 neurons and 5 neurons;

[0135] Further, the horizontal self-correction, according to the above data, the output information of the force sensor in the horizontal torque measurement system and the inertial navigation unit in the high-precision torque calibration system is taken as the model input information, the high-precision program-controlled torque is taken as the output information, a reliable neural network prediction model is trained, and the horizontal self-correction is completed. Wherein, the neural network model adopts the network structure of 7-10-5-2, the input layer is the output information of the force sensor and the inertial navigation unit, the output layer is the horizontal torque of the x-axis and the y-axis, and the middle contains two layers of hidden layers respectively composed of 10 and 5 neurons, and the mathematical expressions of each layer are as follows:

[0136] The input layer is

[0137]

[0138] Wherein, is a 7-dimensional input vector, is the output data of the force sensor, is the three-axis attitude data output by the inertial navigation unit.

[0139] The first hidden layer has 10 neurons, and the input-output expression is

[0140]

[0141] Wherein, represents the output vector of the first hidden layer, W1is a weight matrix, b1is a bias vector.

[0142] The second hidden layer has 5 neurons, and the input-output expression is

[0143]

[0144] wherein, represents the output vector of the first hidden layer, W1is a weight matrix, b1is a bias vector.

[0145] The output layer is

[0146]

[0147] wherein, represents the output vector of the output layer, respectively, are the horizontal moments of forces in the x and y axes, W2is a weight matrix, b2is a bias vector.

[0148] S5.2. The vertical moment self-correction method is constructed by using polynomial fitting to obtain a z-axis error compensation relationship model; based on and solving the z-axis disturbance moment, the calculation formula is as follows:

[0149]

[0150] wherein, is the z-axis disturbance moment, and are the nominal force arms corresponding to and ;

[0151] The mapping relationship between the attitude angle and the disturbance moment is established , and the expression is:

[0152]

[0153] wherein, k is the data sample index, N is the total number of data samples, is the x-axis attitude data, y-axis attitude data, and z-axis attitude data of the kth sample, is the disturbance moment around the z-axis corresponding to the kth sample;

[0154] The polynomial regression is performed on the mapping relationship between the attitude angle and the disturbance moment, and the z-axis error compensation relationship model is generated as follows:

[0155] ​​​​

[0156] wherein, is the z-axis compensation moment, is a polynomial base function, , is a fitting coefficient, j is the index of the number of polynomial base functions, and m is the highest order of polynomial regression, and the establishment of the z-axis error compensation relationship model realizes self-correction of the vertical moment.

[0157] Further, the step S5 loads the precision moment sensitive system, and the self-correction method of the control moment gyro moment output characteristic measuring device is completed as follows:

[0158] Before formal measurement of the measured device, first of all, the super-static suspension system is also ensured to be in a leveling state, then the precision moment sensitive system is loaded to the instrument installation platform, and each force sensor output is set to 50% of the full scale, so as to obtain a self-correction initial state of the control moment gyro moment output characteristic measuring device;

[0159] Then, the data monitoring and control system sends a programmed moment sequence to the single-axis mass adjustment robot in the high-precision moment calibration system, and the single-axis mass adjustment robot outputs high-precision programmed moments by changing the relative position of the programmed mass adjustment assembly according to the self-calibration result;

[0160] Then, the output information of the high-precision programmed moment, the force sensor and the inertial navigation unit is stored in real time and synchronously, and the high-precision standard moment measuring system is used for self-correction operation of the horizontal moment and the vertical moment respectively;

[0161] After the self-correction is completed, the measuring system and the model are used to realize high-precision moment measurement.

[0162] Further, when the measured device outputs a moment, the output information of the force sensor and the inertial navigation unit is read, which is input to the trained network prediction model on one hand, and the neural network prediction model outputs the measured high-precision horizontal output moment, and on the other hand, it is input to the z-axis error compensation relationship model, and the z-axis real-time calculation moment is subtracted from the z-axis error moment calculated by the z-axis error compensation relationship model, so as to obtain a high-precision vertical output moment.

[0163] S6. Adjusting the control moment gyro moment output characteristic measuring device to be in a self-correction initial state, turning on the measured device, performing moment measurement, calculating the output moment of the measured device based on the prediction neural network model and the z-axis error compensation relationship model and the output moment formula, saving the experimental data, and completing the experiment.

[0164] It has to be noted that the terms "first", "second", and the like in connection with an entity or action refer to this entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises", "comprising", or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by "comprises... a" does not, without further constraints, exclude the presence of additional elements of the process, method, article, or apparatus.

[0165] While the application has been described with reference to specific implementations thereof, it should be understood that various modifications and substitutions can be made by those skilled in the art without departing from the scope of the present application. In particular, any one of the features of the present application disclosed above can be utilized independently of any other and the scope of the application should not be limited by the specific embodiments disclosed herein, but should be given the widest coverage possible in its true scope.

Claims

1. A control moment gyroscope torque output characteristic measuring device, characterized by, The super static suspension system, the precise moment sensitive system, the high-precision moment calibration system and the data monitoring and control system are included. The super static suspension system includes the gas floating ball bearing (1), the instrument installation platform (2) and the support unloading device (17), the gas floating ball bearing (1) is arranged in the gas floating ball bowl (3), the gas floating ball bearing (1) is tightly connected with the instrument installation platform (2), the measured equipment (16) is placed on the instrument installation platform (2), the pressure sensor (18) is installed on the support unloading device (17); The precise moment sensitive system is composed of the horizontal moment measuring system (20) and the vertical moment measuring system (21); 4 groups of horizontal moment measuring systems (20) are evenly arranged on the instrument installation platform (2) with an angle of 90°, which is used for converting the horizontal moment measurement into force measurement; the vertical moment measuring system (21) includes a high-precision force sensor group (22), a gas floating bearing (23) and an auxiliary extension mechanism (25), the auxiliary extension mechanism (25) is rigidly connected with the instrument installation platform (2); the high-precision force sensor group (22) is composed of two force sensors, which is installed outside the two gas floating surfaces (24) formed between the gas floating bearing (23) and the auxiliary extension mechanism (25), which is used for realizing z-axis moment measurement and decoupling z-axis moment from xy-axis moment measurement; The high-precision moment calibration system is placed on the instrument installation platform (2) and includes an inertial navigation unit (13) and a single-axis mass adjustment robot (14), the number of single-axis mass adjustment robots (14) is two, which are orthogonally distributed between the measured equipment (16) and the horizontal moment measuring system (20), which is used for realizing the instrument installation platform (2) leveling work while outputting high-precision standard moment; the inertial navigation unit (13) is placed between the measured equipment (16) and the horizontal moment measuring system (20) and faces the single-axis mass adjustment robot (14), which is used for real-time monitoring of the super static suspension system attitude information; The data monitoring and control system (15) is connected with the super static suspension system, the precise moment sensitive system and the high-precision moment calibration system through wireless communication devices.

2. The device for measuring torque output characteristics of a control moment gyroscope according to claim 1, wherein The horizontal moment measuring system (20) includes a micro-touch unit (4), a high-precision force sensor (5), a high-precision electric linear push rod (6), an air cushion (7), a pneumatic actuator (8), a pneumatic pre-tightening unit (9), a composite cross beam (10), a gas floating guide rail (11) and a gas floating sliding block (12). The composite cross beam (10) is fixedly installed on the air floating guide rail (11), the high-precision electric linear push rod (6) is rigidly connected with the air floating slider (12) through the composite cross beam (10), the pneumatic actuator (8) penetrates through the air-tight cavity of the composite cross beam (10) and acts on the upper surface of the air floating slider (12), the pneumatic pre-tightening unit (9) is integrated in the pneumatic actuator (8) and is independently controlled through the air pressure pipeline, the output end of the pneumatic pre-tightening unit (9) is coupled with the air floating slider (12), the air floating slider (12) is suspendedly installed in the rolling track of the air floating guide rail (11), the lower surface of the air floating slider (12) is fixedly connected with the high-precision force sensor (5), the micro-touch unit (4) is connected with the measuring end of the high-precision force sensor (5), the high-precision electric linear push rod (6) pre-presses the micro-touch unit (4) on the air cushion (7) placed on the instrument installation platform (2) through the high-precision force sensor (5), and the pre-pressing of the high-precision force sensor (5) and the instrument installation platform (2) is realized in cooperation with the locking effect of the pneumatic pre-tightening unit (9).

3. The device for measuring torque output characteristics of a control moment gyroscope according to claim 1, wherein The support unloading device (17) has three groups in total and is distributed at an angle of 120° and is used for supporting and roughly leveling the instrument installation platform (2), and the two single-shaft mass adjustment robots (14) are robot A and robot B respectively.

4. The device for measuring torque output characteristics of a control moment gyroscope according to claim 1, wherein The data monitoring and control system (15) is responsible for receiving the output information of sensitive elements and control elements in each system, sending mass adjustment and loading instructions to the high-precision torque compensation system and the precise torque sensitive system, and calculating the compensation information and the measured torque at the same time.

5. The device for measuring torque output characteristics of a control moment gyroscope according to claim 1, wherein The measured force results of the four groups of horizontal torque measurement systems (20) are F1, F2, F3 and F4 respectively, the theoretical force arms between each force sensor and the rotation center are L1, L2, L3 and L4 respectively, the measured force results of the vertical torque measurement system (21) are F5 and F6 respectively, the theoretical force arms between each force sensor and the rotation center are L5 and L6 respectively, and the output torque formula under the ideal condition is obtained according to the balance method for measuring torque as follows: wherein, , and are the measured moment results in the x-direction, y-direction and z-direction, respectively.

6. A method for measuring the torque output characteristics of a control moment gyroscope, implemented by means of a device for measuring the torque output characteristics of a control moment gyroscope according to any one of claims 1 to 4, characterized in that, The method comprises the following steps: S1. confirming whether the air floating ball bearing is ventilated, whether the power supply of the control torque gyro torque output characteristic measuring device is turned on, and entering the working state after the air floating ball bearing is ventilated and the power supply is turned on; S2. manually adding load weights on the instrument installation platform, reading the pressure sensor values on the support unloading device, and completing the rough leveling of the control torque gyro torque output characteristic measuring device when the pressure sensor values are basically equal; S3. removing the support unloading device, taking the inertial navigation unit as feedback, controlling the motion of the single-shaft mass adjustment robot, and completing the fine leveling of the control torque gyro torque output characteristic measuring device when the instrument installation platform posture displayed by the inertial navigation unit reaches the predetermined level requirement; S4. completing the self-calibration of the high-precision torque calibration system based on the high-precision standard torque self-calibration method, and obtaining the high-precision standard torque; S5. loading the precise torque sensitive system based on the high-precision standard torque measurement system self-correction method, completing the self-correction of the control torque gyro torque output characteristic measuring device, obtaining the prediction neural network model and the z-axis error compensation relationship model. S6. Adjusting a control moment gyro torque output characteristic measuring device to be in a self-calibration initial state, turning on the measured device, performing torque measurement, calculating the output torque of the measured device based on a predictive neural network model and a z-axis error compensation relationship model and an output torque formula, saving experimental data, and completing the experiment.

7. The method of claim 6, wherein: The specific implementation method of the high-precision standard torque self-calibration method in step S4 includes the following steps: S4.

1. Based on a kind of control moment gyro moment output characteristic measuring device, under the condition of fine trimming, the position code of the mass load with known weight is set on the instrument mounting platform , ; S4.

2. Without loading the precision torque sensitive system, read the inertial navigation unit data through the data monitoring and control system and control the programmed mass adjustment assembly in robot A and robot B to move, so as to realize the horizontal leveling of the super static suspension system; S4.

3. Add a known mass load on the instrument mounting platform, the mass load is installed at position P1, level the self-stable suspension system again, record the measurement system state at this time as the initial zero position state of self-calibration, record the mass load mass at this time and programmed mass adjustment assembly positions in robot A and robot B; S4.

4. sequentially according to position encoding Move the mass load in ascending order, and after each movement of the mass load, repeat the horizontal leveling work of the super-static suspension system, and record the relative displacement of each movement of the mass load And the relative displacement of each horizontal leveling movement of the programmed mass adjustment assembly in robot A and robot B And Where i represents the number of mass load movements, and N sets of data are obtained; S4.

5. Define unknown quantities including the total mass of the program-controlled mass adjustment assembly in robot A and robot B, respectively and , the installation error included angle of robot A and the x-axis , the installation error included angle of robot B and the y-axis , the construction of high-precision standard torque self-calibration calculation method is as follows: S4.5.

1. Constructing a least squares system, constructing a linear equation group based on N groups of measurement data as follows: Define the variables to be solved as ; S4.5.

2. Solving for the intermediate variables based on the improved total least squares method: Let the coefficient matrix be denoted as , the observation vector be denoted as , construct the augmented matrix and perform SVD singular value decomposition as follows: wherein the coefficient matrix , the observation vector , is a singular value matrix, is a left singular vector matrix; Let the last column of be modified to where is a regularization parameter, then the above variables to be solved are written as: ； S4.5.

3. Calculating the programmed mass adjustment assembly mass, obtaining: ； S4.5.

4. Separating the angle parameters, and solving the final error installation angle according to N groups of data, obtaining: ； S4.5.

5. After the above self-calibration, the high-precision standard torque self-calibration output formula is as follows: wherein, is the x-axis high precision standard torque, is the y-axis high precision standard torque, and are the relative positions of the programmable mass adjustment assembly of the two robots under program control, respectively.

8. The method of claim 7, wherein: The specific implementation method of the high-precision standard torque measurement system self-calibration method in step S5 includes the following steps: S5.

1. Constructing a neural network prediction model for horizontal moment self-correction, the neural network prediction model adopts a structure of input layer-2 hidden layers-output layer, the input layer is the output information of the force sensor and the inertial navigation unit, including a 7-dimensional input vector and , is the three-axis attitude data output by the inertial navigation unit, the output layer is the horizontal moment of the x-axis and the y-axis, and the two hidden layers are composed of 10 neurons and 5 neurons respectively; S5.

2. Constructing vertical moment self-correction method is to obtain the z-axis error compensation relationship model by polynomial fitting; based on and Solving the z-axis disturbance moment, the calculation formula is as follows: wherein, is the z-axis disturbance torque, and respectively and the corresponding nominal force arm; Establishing a mapping between attitude angles and disturbance torques , the expression is: Wherein, k is a data sample index, N is the total number of data samples, is the x-axis attitude data, y-axis attitude data, z-axis attitude data of the kth sample, is the interference torque around the z-axis corresponding to the kth sample; Performing polynomial regression on the mapping relationship between the attitude angle and the disturbance torque to generate a z-axis error compensation relationship model as follows: wherein, is the z-axis compensation moment, is a polynomial base function, , is a fitting coefficient, j is the index of the number of polynomial base functions, and m is the highest order of polynomial regression. The establishment of this z-axis error compensation relationship model realizes the self-correction of the vertical moment.

9. The method of claim 8, wherein: The method for self-calibration of the control moment gyro torque output characteristic measuring device in step S5 is to load the precision torque sensitive system, which includes the following steps: Before formal measurement of the measured device, first of all, ensure that the super static suspension system is in a leveled state, then load the precision torque sensitive system to the instrument installation platform, and set the output of each force sensor to 50% of the full scale, to obtain a self-calibration initial state of the control moment gyro torque output characteristic measuring device; Then, the data monitoring and control system sends a programmed torque sequence to the single-axis mass adjustment robot in the high-precision torque calibration system, and the single-axis mass adjustment robot outputs high-precision programmed torque by changing the relative position of the programmed mass adjustment assembly according to the self-calibration result; Then, the output information of the high-precision programmed torque, the force sensor and the inertial navigation unit is stored in real time and synchronously, and the high-precision standard torque measurement system self-calibration method is used to perform self-calibration operation on the horizontal torque and the vertical torque respectively; After the self-calibration is completed, the measurement system and the model are used to realize high-precision torque measurement.

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