Method and device for calculating reaction wheel compensation torque, and electronic device

Abstract

The application provides a reaction wheel compensation torque calculation method, device and electronic equipment, wherein the calculation method comprises: calculating the instruction torque allocated by the reaction wheel in the reaction wheel group based on the target value of the attitude control torque, to calculate a target speed increment, then calculating a first difference value between the target speed increment and an actual speed increment, and calculating a first compensation torque based on the first difference value by using proportional integral control, calculating a second compensation torque based on the sliding smoothing of the first compensation torque in the current M periods and the previous periods, performing low-pass filtering on the second compensation torque in the current period and the second compensation torque in the previous period to obtain a third compensation torque, compensating the third compensation torque to the instruction torque of the reaction wheel, and performing amplitude limiting output to the corresponding reaction wheel, so that the three-axis control torque output by the reaction wheel group follows the three-axis instruction control torque of the satellite, avoids the risk of unstable control, and improves the stability and control precision of the spacecraft attitude control.

Description

Technical Field

[0001] This application mainly relates to the field of spacecraft attitude control technology, and in particular to a method, device and electronic equipment for calculating the compensation torque of a reaction wheel. Background Technology

[0002] As a key actuator in the satellite attitude control system, the reaction wheel primarily applies control torque to the satellite by exchanging momentum with the satellite body through changes in its own angular momentum, thereby achieving high-precision attitude control. Many factors influence the accuracy of the reaction wheel's attitude control, including the satellite attitude control algorithm, the resolution of the reaction wheel's output torque, the accuracy of rotational speed measurement, frictional torque (also known as loss torque), and micro-vibrations. Among these, for high-precision attitude control tasks, the deviation between the actual output torque of the reaction wheel and the commanded torque directly affects the performance of the attitude closed-loop control, and frictional torque is one of the significant factors contributing to this deviation.

[0003] Depending on the form of control commands, reaction wheels mainly include torque-voltage controlled or current-controlled reaction wheels, as well as speed-controlled reaction wheels. For torque-voltage controlled or current-controlled reaction wheels, the satellite typically sends torque-voltage commands or motor current commands to the reaction wheel. These types of reaction wheels generally do not have built-in friction torque compensation control functions; therefore, during use, their output torque will be affected by friction torque. It is evident that the current satellite attitude control using analog torque command or current-controlled reaction wheels suffers from poor friction torque compensation accuracy and may adversely affect the satellite's control stability. Summary of the Invention

[0004] The technical problem to be solved by this application is to provide a method, device and electronic equipment for calculating the compensation torque of the reaction wheel, so as to improve the stability and control accuracy of spacecraft attitude control.

[0005] To address the aforementioned technical problems, in a first aspect, this application provides a method for calculating the compensation torque of a reaction wheel, comprising: calculating the command torque allocated to the reaction wheel in the reaction wheel assembly based on the target value of the attitude control torque; calculating the actual speed increment of the reaction wheel in the reaction wheel assembly in the current cycle; calculating the target speed increment of the corresponding reaction wheel based on the command torque allocated to the reaction wheel in the reaction wheel assembly in the current cycle; calculating a first difference between the target speed increment and the actual speed increment, and calculating a first compensation torque based on the first difference using a proportional-integral control algorithm.

[0006] Optionally, the method further includes: designating at least one reaction wheel in the reaction wheel assembly as a speed-controlled reaction wheel, and the remaining reaction wheels as non-speed-controlled reaction wheels.

[0007] Optionally, the mounting vector of the at least one speed-regulating reaction wheel is set to... .

[0008] Optionally, the method further includes: performing a sliding smoothing calculation based on the first compensation torque of the current cycle and the first compensation torque of the remaining cycles in the sliding window to obtain the second compensation torque.

[0009] Optionally, the method further includes: after obtaining the first compensation torque of the current period, moving the second compensation torque of the current period into the sliding window, and moving the first compensation torque of the earliest period out of the sliding window.

[0010] Optionally, the method further includes: performing low-pass filtering based on the second compensation torque and in combination with the second compensation torque of the previous cycle to obtain a third compensation torque.

[0011] Optionally, the method further includes: after obtaining the third compensation torque of the current cycle, storing the second compensation torque of the current cycle as the second compensation torque value of the previous cycle.

[0012] Optionally, the method further includes: limiting the compensation torque so that the compensation torque does not exceed the maximum compensation torque of the reaction wheel.

[0013] Secondly, this application provides a calculation device for the compensation torque of a reaction wheel, comprising: a torque allocation module configured to calculate a command torque allocated to the reaction wheel in the reaction wheel assembly based on a target value of the attitude control torque; a first calculation module configured to calculate the actual speed increment of the reaction wheel in the reaction wheel assembly in the current cycle; a second calculation module configured to calculate a target speed increment of the corresponding reaction wheel based on the command torque allocated to the reaction wheel in the reaction wheel assembly in the current cycle; and a third calculation module configured to calculate a first difference between the target speed increment and the actual speed increment, and calculate a first compensation torque based on the first difference using a proportional-integral control algorithm.

[0014] Thirdly, this application provides an electronic device, including: a processor and a memory, wherein the memory stores a program or instructions running on the processor, and the program or instructions, when executed by the processor, implement the steps of the method for calculating the reaction wheel compensation torque as described in the first aspect.

[0015] Fourthly, this application provides a readable storage medium storing a program or instructions that, when executed by a processor, implement the steps of the method for calculating the reaction wheel compensation torque as described in the first aspect.

[0016] Compared with the prior art, this application has the following advantages: by allocating the attitude control torque target to the command torque of each reaction wheel, and calculating the target speed increment based on the command torque, and simultaneously calculating the actual speed increment based on the actual measured speed of the reaction wheel, the error between the target speed response and the actual speed response is used to characterize the influence of friction torque or loss torque in the current operating state of the reaction wheel. Then, based on this error, a proportional-integral control algorithm is used to calculate the first compensation torque, realizing real-time compensation for the friction torque of the reaction wheel. This solves the problem of insufficient compensation accuracy of fixed lookup table compensation or equivalent torque compensation under wide speed range and time-varying friction conditions, improves the tracking accuracy of the actual output torque of the reaction wheel to the command torque, reduces the influence of friction torque on the satellite attitude closed-loop control, and enhances the stability and control accuracy of satellite attitude control. Attached Figure Description

[0017] The accompanying drawings are included to provide a further understanding of this application; they are incorporated into and constitute a part of this application. The drawings illustrate embodiments of this application and, together with this specification, serve to explain the principles of this application. In the drawings: Figure 1 This is a flowchart illustrating a method for calculating the compensation torque of a reaction wheel according to an embodiment of this application; Figure 2 This is another control block diagram of the calculation method of the reaction wheel compensation torque according to an embodiment of this application; Figure 3 This is a block diagram of satellite attitude control based on reaction wheel feedforward compensation according to an embodiment of this application; Figure 4 This is a schematic diagram of the friction torque model of the reaction wheel in one embodiment of this application; Figure 5 This is a schematic diagram of the speed change of the reaction wheel assembly in one embodiment of this application; Figure 6 This is a schematic diagram of the satellite's three-axis attitude angle control error and inertial angular velocity variation in one embodiment of this application; Figure 7 This is a schematic diagram of the command torque and actual output torque of the non-steady-speed reaction wheel in one embodiment of this application; Figure 8 This is a schematic diagram of the frictional torque and estimated calculated torque of the non-steady-speed reaction wheel in one embodiment of this application; Figure 9 This is a schematic diagram illustrating the error between the output torque and the command torque of the non-steady-speed reaction wheel in one embodiment of this application; Figure 10 This is a schematic diagram of the structure of a calculation device for the compensation torque of a reaction wheel according to an embodiment of this application; Figure 11 This is a schematic diagram of an electronic device according to an embodiment of this application. Detailed Implementation

[0018] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are merely some examples or embodiments of this application. For those skilled in the art, these drawings can be applied to other similar scenarios without creative effort. Unless obvious from the context or otherwise specified, the same reference numerals in the drawings represent the same structures or operations.

[0019] As indicated in this application and claims, unless the context clearly indicates otherwise, the words "a," "an," "an," and / or "the" are not specifically singular and may include plural forms. Generally speaking, the terms "comprising" and "including" only indicate the inclusion of explicitly identified steps and elements, which do not constitute an exclusive list, and the method or apparatus may also include other steps or elements.

[0020] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, these terms have no special meaning and therefore should not be construed as limiting the scope of protection of this application. In addition, although the terminology used in this application is selected from commonly known and used terms, some terms mentioned in this application's specification may have been chosen by the applicant according to his or her judgment, and their detailed meanings are explained in the relevant sections of this description. Moreover, this application should be understood not only through the actual terms used, but also through the meaning implied by each term.

[0021] Flowcharts are used in this application to illustrate the operations performed according to embodiments of this application. It should be understood that the preceding or following operations are not necessarily performed in exact order. Instead, various steps can be processed in reverse order or simultaneously. Furthermore, other operations may be added to these processes, or one or more steps may be removed from them.

[0022] In satellite attitude control, for analog torque command type or current control type reaction wheels, since these types of reaction wheels usually do not have their own friction torque compensation function, it is necessary to process the friction torque of the reaction wheel assembly in the satellite attitude control system. Currently, commonly used engineering methods include equivalent torque compensation method, as well as lookup table and linear interpolation methods.

[0023] The equivalent torque compensation method is typically applicable to scenarios where there is only one speed-controlled reaction wheel in the reaction wheel assembly. This method utilizes the holding torque required by the speed-controlled reaction wheel to maintain the target rotational speed, and based on the zero-vector relationship of the reaction wheel mounting matrix, it equivalently distributes this holding torque to the control commands of other variable-speed control reaction wheels, thereby compensating for the frictional torque of the wheel assembly. However, the equivalent torque compensation method is generally more suitable for situations where the absolute differences in the rotational speeds of the reaction wheels in the wheel assembly are small. When the rotational speed differences between different reaction wheels are large, the differences in frictional torque among the reaction wheels become more significant. Equivalent compensation based solely on the holding torque of the speed-controlled reaction wheel is insufficient to accurately reflect the actual frictional torque of other reaction wheels at different rotational speeds and operating conditions, thus easily leading to a decrease in compensation effectiveness. For some near-Earth LEO orbit satellites, or some high-orbit satellites with low attitude stability requirements, momentum unloading of the reaction wheel assembly can be achieved using magnetic torquers or thrusters, maintaining the rotational speeds of each reaction wheel within a range that is small compared to the nominal speed. In such scenarios, the equivalent torque compensation method can achieve a certain compensation effect. However, for satellites that require long-term stable operation, are not equipped with magnetic torque generators, or are not suitable for frequent use of thrusters for momentum unloading, the operating speed range of the reaction wheels is often wide, and the frictional torque between different reaction wheels and at different speeds of the same reaction wheel varies greatly. The equivalent torque compensation method is difficult to accurately adapt to the actual frictional torque changes of each reaction wheel, and the compensation effect is relatively limited, affecting the satellite control accuracy and stability.

[0024] Lookup tables and linear interpolation methods typically involve pre-storing the correspondence between reaction wheel speed and friction torque obtained from ground tests on the satellite. During satellite operation, the pre-stored speed-friction torque data table is consulted based on the real-time collected reaction wheel speed, and the friction torque at the current speed is obtained through linear interpolation or other methods. This friction torque is then used for compensation. However, the friction torque of the reaction wheel is not solely determined by its speed. The friction torque of the same reaction wheel or different reaction wheels is also affected by various factors such as usage time, operating duration, satellite cabin environment, and speed. Therefore, the friction torque characteristics of the reaction wheel may change at different times, in different environments, and at different operating stages. A fixed speed-friction torque table established based on ground test data cannot accurately reflect the actual friction torque of the reaction wheel during long-term operation in orbit. When the friction torque exhibits significant time-varying characteristics, individual differences, or environmental dependence, lookup tables and linear interpolation methods are prone to discrepancies between the compensation value and the actual friction torque, thus affecting the tracking accuracy of the reaction wheel's output torque to the command torque.

[0025] It is evident that the compensation accuracy of existing equivalent torque compensation methods is easily affected by differences in reaction wheel speed and individual friction. Furthermore, lookup tables and linear interpolation methods struggle to adapt to the dynamic changes in reaction wheel friction torque caused by time, environment, operating conditions, and speed variations. For high-precision satellite attitude control systems using analog torque command or current control reaction wheels, existing friction torque processing methods cannot accurately and in real-time obtain the actual friction torque of each reaction wheel. This may lead to a deviation between the actual output torque of the reaction wheel and the assigned command torque, thus affecting the accuracy and stability of the satellite attitude closed-loop control. In severe cases, existing compensation methods may even cause the satellite attitude control stability to exceed expected targets.

[0026] refer to Figure 1 As shown, this embodiment provides a method for calculating the compensation torque of a reaction wheel. Method 100 includes: S110, calculating the command torque allocated to the reaction wheel in the reaction wheel assembly based on the target value of the attitude control torque; S120, calculating the actual speed increment of the reaction wheel in the reaction wheel assembly in the current cycle; S130, calculating the target speed increment of the corresponding reaction wheel based on the command torque allocated to the reaction wheel in the reaction wheel assembly in the current cycle; S140, calculating a first difference between the target speed increment and the actual speed increment, and calculating a first compensation torque based on the first difference using a proportional-integral control algorithm.

[0027] In this embodiment, taking satellite three-axis attitude control as an example, based on the satellite three-axis attitude control torque... It can calculate the torque distribution of the reaction wheel assembly:

[0028] in, The satellite's three-axis control torque, calculated based on the satellite attitude control algorithm, is a 3×1 vector. The installation matrix for the reaction wheels. To obtain the pseudo-inverse function, if the satellite is equipped with N reaction wheels, then It is a 3×N matrix. It is an N×3 matrix. The distributed torque of the reaction wheel is an N×1 vector.

[0029] For the j-th reaction wheel in the reaction wheel assembly, its assigned command torque is:

[0030] Where j = 1, ..., N.

[0031] In this embodiment, the calculation of the actual rotational speed increment can be carried out in the following way, but is not limited to this. For example, for a certain reaction wheel... Record and store the initial speed of the reaction wheel. Read the currently collected reaction wheel speed Then calculate the actual speed increment corresponding to the current moment (current cycle / current software cycle). for:

[0032] Correspondingly, the command torque of the reaction wheel at the current moment is The cumulative speed increment of the command torque relative to the initial moment. for:

[0033] in, This is the moment of inertia of the reaction wheel.

[0034] Therefore, the error (first difference) between the calculated cumulative speed increment of the commanded torque (target speed increment) and the actual speed increment is calculated. for:

[0035] Therefore, the first compensation torque can be calculated using a proportional-integral (PI) control algorithm based on the aforementioned error. Specifically:

[0036] in, This is the proportional control coefficient for the reaction wheel's compensating torque. The integral control coefficient of the reaction wheel compensation torque. After friction torque compensation, the aforementioned first compensation torque can be used as the torque compensation quantity input into the control torque of the reaction wheel to achieve real-time torque control of the reaction wheel.

[0037] As can be seen, the method in this embodiment allocates the attitude control torque target to the command torque of each reaction wheel, calculates the target speed increment based on the command torque, and calculates the actual speed increment based on the actual measured speed of the reaction wheel. This allows the error between the target speed response and the actual speed response to characterize the influence of frictional torque or loss torque in the current operating state of the reaction wheel. Then, based on this error, a proportional-integral control algorithm is used to calculate the first compensation torque, achieving real-time compensation for the frictional torque of the reaction wheel. This solves the problem of insufficient compensation accuracy of fixed lookup table compensation or equivalent torque compensation under wide speed ranges and time-varying friction conditions, improving the tracking accuracy of the actual output torque of the reaction wheel to the command torque. When the first compensation torque is used to subsequently correct the input torque command of the reaction wheel, it can reduce the deviation between the actual output torque of the reaction wheel and the allocated command torque, making the actual output torque of the reaction wheel assembly more accurately follow the target value of the attitude control torque. This reduces the disturbance influence of frictional torque on the satellite attitude closed-loop control, improving the satellite attitude control accuracy and closed-loop control stability.

[0038] In some embodiments, method 100 further includes designating at least one reaction wheel in the reaction wheel assembly as a speed-controlled reaction wheel, and the remaining reaction wheels as non-speed-controlled reaction wheels. Preferably, the mounting vector of the at least one speed-controlled reaction wheel is set to... This prevents it from participating in the calculation of the torque distribution of the satellite's three-axis control torque in the reaction wheel assembly.

[0039] In this embodiment, at least one reaction wheel in the reaction wheel assembly maintains a certain steady-state speed, thus playing a role in maintaining zero momentum control of the reaction wheel assembly. For a certain steady-speed control reaction wheel... Its torque is:

[0040] in, This is the proportional control coefficient for the reaction wheel speed. Integral control coefficient for reaction wheel speed. This is the moment of inertia of the reaction wheel.

[0041] If defined The installation matrix for N reaction wheel assemblies can be specifically expressed as:

[0042] in, Let be the installation vector of the i-th reaction wheel under the satellite body, a 3×1 dimensional vector. When the i-th reaction wheel is a speed-regulating reaction wheel, then during the torque distribution process of the satellite flywheel assembly, the installation vector corresponding to the i-th speed-regulating reaction wheel is... Set to a zero vector, that is In this way, the speed-stabilizing control reaction wheel is effectively excluded in the satellite's three-axis control torque distribution process, and is only used to maintain its own speed stability.

[0043] In this case, due to the installation vector of the speed control reaction wheel... Therefore, the torque distribution among the reaction wheels in the reaction wheel assembly is actually the torque distribution among the non-steady-speed reaction wheels in the reaction wheel assembly. That is, for the j-th non-steady-speed control reaction wheel in the reaction wheel assembly, its assigned command torque is:

[0044] The above method prevents the attitude control torque distribution from causing additional speed changes in the steady-speed control reaction wheel, thus ensuring the steady-speed control reaction wheel maintains the zero-momentum state of the wheel set. Simultaneously, the remaining non-steady-speed control reaction wheels participate in the attitude control torque distribution according to the modified installation matrix, ensuring that subsequent friction torque compensation is only performed on the non-steady-speed control reaction wheels involved in attitude control, reducing control coupling and improving the stability of the compensation control.

[0045] In some embodiments, method 100 further includes performing a sliding smoothing calculation based on the first compensation torque of the current period and the first compensation torque of the remaining periods in the sliding window to obtain a second compensation torque.

[0046] In this embodiment, considering the influence of the sampling noise of the reaction wheel speed, the compensation torque for reaction wheel j (non-steady-speed control reaction wheel) is adjusted. Perform M calculations to smooth the compensation torque As shown below:

[0047] in, The total compensation torque of the reaction wheel j over M cycles is given. The number of software cycles (M) should generally not be too long, typically ranging from 0.5 seconds to tens of seconds in engineering practice (when the satellite reaction wheel control cycle is 250ms@4Hz, M = 2 to several tens). (4 beats). The smoothing compensation torque of the reaction wheel j obtained from the above calculation. This is the second compensation torque. When the second compensation torque is used to correct the input torque command of the reaction wheel, it can reduce the deviation between the actual output torque of the reaction wheel and the assigned command torque, so that the actual output torque of the reaction wheel assembly can more accurately follow the target value of the attitude control torque, thereby reducing the disturbance effect of friction torque on the satellite attitude closed-loop control and improving the satellite attitude control accuracy and closed-loop control stability.

[0048] In some embodiments, method 100 further includes, after obtaining the second compensation torque of the current period, moving the first compensation torque of the current period into the sliding window and moving the first compensation torque of the earliest period out of the sliding window, i.e., updating... The values ​​for the first M-1 software cycles are shown below:

[0049] By employing the above method, the sliding window always stores the first compensation torque corresponding to the current cycle and the previous M-1 cycles. The second compensation torque is obtained by averaging the M first compensation torques in the sliding window. This reduces the impact of reaction wheel speed sampling errors and high-frequency noise on the calculation results of the compensation torque in a single cycle, making the compensation torque change more stable and improving the stability of subsequent command torque feedforward compensation.

[0050] In some embodiments, method 100 further includes low-pass filtering based on the second compensation torque and in combination with the second compensation torque of the previous cycle to obtain a third compensation torque. For example, smoothing the compensation torque on the reaction wheel. Perform low-pass filtering secondary processing calculations:

[0051] in, For the third compensating torque, For the second compensation torque The previous period value, t s The filter time constant is in the range of 0 to 1, and the magnitude of this parameter determines the cutoff frequency of the low-pass filter.

[0052] refer to Figure 2As shown, this embodiment considers that high-frequency noise from velocity measurement errors can cause significant fluctuations in the estimated friction torque of the reaction wheel, affecting the stability of the control system. It introduces smoothing and low-pass filtering methods to reduce the impact of large fluctuations in the calculated friction torque value on the satellite closed-loop control system and avoid the influence of high-frequency noise from the reaction wheel speed sampling on the satellite's high-precision attitude control. Specifically, based on sliding filtering, it further suppresses high-frequency components in the compensation torque, making the change of the third compensation torque more continuous and stable, reducing the impact of reaction wheel speed sampling noise on the friction torque compensation result, and preventing rapid changes in the compensation torque from disturbing the stability of the satellite attitude closed-loop control. When the third compensation torque is used to subsequently correct the input torque command of the reaction wheel, it can reduce the deviation between the actual output torque of the reaction wheel and the allocated command torque, allowing the actual output torque of the reaction wheel assembly to more accurately follow the target value of the attitude control torque. This reduces the disturbance impact of friction torque on the satellite attitude closed-loop control, improving the satellite attitude control accuracy and closed-loop control stability.

[0053] In some embodiments, method 100 further includes, after obtaining the third compensation torque of the current cycle, storing the second compensation torque of the current cycle as the second compensation torque value of the previous cycle, i.e., updating... Values ​​for the previous software cycle:

[0054] After the low-pass filtering process is completed in the current cycle, the second compensation torque of the current cycle is stored as the second compensation torque of the previous cycle to ensure that the low-pass filtering process is executed continuously between adjacent software cycles.

[0055] In some embodiments, method 100 further includes limiting the compensation torque to ensure that the compensation torque does not exceed the maximum compensation torque of the reaction wheel, thus preventing the calculated compensation control torque from being too large, which in extreme cases exceeds the commanded control torque and affects the stability of satellite attitude control. For example:

[0056] in, The maximum compensation control torque of the reaction wheel is generally set to 1.5 to 2 times the required loss torque of the reaction wheel, but not greater than the maximum input control torque of the reaction wheel. , It is a symbolic function.

[0057] refer to Figure 3As shown, the final calculated compensation torque (i.e., the third compensation torque) is superimposed with the expected command torque to obtain the corrected actual command torque sent to the reaction wheel. This outputs the command torque to the reaction wheel, ensuring that its output torque follows the expected torque command, achieving a high tracking result. Therefore, in subsequent processes, the non-steady-speed control reaction wheel... Using compensating torque The input torque command for the feedforward correction reaction wheel is:

[0058] It is important to note that the input torque of the output reaction wheel can be limited to prevent the control torque of the reaction wheel from exceeding its controllable range.

[0059] in, The maximum control torque of the reaction wheel, It is a symbolic function.

[0060] In some embodiments, the calculation method is applied to a reaction wheel with a rotational speed measurement accuracy better than approximately 0.1 rpm. 0.1 rpm is an engineering reference value, which is comprehensively related to factors such as the satellite's inertia, the reaction wheel's inertia, the reaction wheel's torque output accuracy, and the satellite's stability requirements. Since the method in this embodiment calculates the compensation torque based on the difference between the target rotational speed increment and the actual rotational speed increment of the reaction wheel, the rotational speed measurement error of the reaction wheel directly affects the calculation accuracy of the actual rotational speed increment, and further affects the estimation accuracy of the compensation torque. Therefore, by using a reaction wheel that meets the above-mentioned rotational speed measurement accuracy requirements, the actual rotational speed increment can more accurately reflect the true rotational speed change of the reaction wheel within the current cycle, thereby improving the reliability and accuracy of the difference between the target rotational speed increment and the actual rotational speed increment.

[0061] The method in this embodiment calculates and compensates for the loss torque of the reaction wheel in real time during satellite closed-loop attitude control, so that the output torque of the reaction wheel follows its control torque, and the output torque of the reaction wheel assembly follows the satellite's three-axis attitude control torque. With a velocity measurement accuracy of 0.1 rpm and higher, the tracking accuracy can reach 1E-4~1E-6 Nm, enabling the satellite attitude control to achieve a high level of attitude control accuracy.

[0062] The following example illustrates the implementation of the method in this embodiment and its corresponding beneficial effects.

[0063] Taking a certain type of satellite equipped with 6 reaction wheels as an example, The installation parameters describing the angular momentum direction of the reaction wheel in the direction vector of the satellite's own system are given by: , The installation matrix of the reaction wheel is as follows:

[0064] The initial rotational speed of the reaction wheel is [1857 -4991 3269 1588 -4723 3000] rpm, the maximum torque of a single reaction wheel is 0.215 Nm, the maximum rotational speed of the reaction wheel is 6000 rpm, and the moment of inertia of the reaction wheel is set to 0.10866 kgm. 2 The static friction + Coulomb friction + viscous friction model is adopted, such as... Figure 4 As shown. The static friction coefficient of the reaction wheel is... When satisfied The reaction wheel outputs a frictional torque of: The coefficient of friction of the reaction wheel is... When satisfied The reaction wheel's kinetic friction torque is Considering the differences between different reaction wheels, the dynamic friction coefficient of the wheel set is set as follows: Reaction wheel A: 2.5E-6 Reaction wheel B: 3.75E-6 Reaction wheel C: 5 E -6 Reaction wheel D: 1.25 E -6 Reaction wheel E: 6.25 E -6 Reaction wheel F: 7.5 E -6 The speed measurement accuracy of any reaction wheel is 0.1 rpm.

[0065] The satellite inertia matrix I is

[0066] The satellite's initial rotational attitude relative to the J2000 series 3-1-2 is [30 0 60]°; the satellite's inertial angular velocity relative to the J2000 series is [0 0 0]°; the satellite's pointing control is inertial pointing, that is, maintaining the initial rotational attitude unchanged; assuming the satellite is affected by the solar radiation pressure torque as [6.67E-05 6.67E-05]... [0.0001] Nm; Affected by the gravitational gradient torque, the geomagnetic torque and aerodynamic drag torque are not considered; Reaction wheel F is selected as the steady-speed reaction wheel, and its kp and ki control coefficients are: kp=0.1, ki=0.005, and the control period is 250ms@4Hz; For reaction wheels A~F, which are non-steady-speed control reaction wheels, their compensation control PI link is used, kp=500, ki=1; For reaction wheels A~F, which are non-steady-speed control reaction wheels, their smoothing filter link uses 4Hz sampling, 1s smooth sliding (averaging of 4 data points) to calculate the sliding mean; For reaction wheels A~F, which are non-steady-speed control reaction wheels, their low-pass filter link has a filtering time constant. = 0.00157, and other different filter bandwidths can also be designed as needed.

[0067] Simulation results are as follows Figures 5-9 As shown, for a steady-speed reaction wheel, limited by a speed measurement accuracy of 0.1 rpm, its control accuracy is within 3000±0.1 rpm. For a non-steady-speed reaction wheel, its actual output torque is consistent with the command torque, and its actual friction torque is consistent with the calculated friction torque. The error between the friction torque and the actual friction torque is within 5E-5 Nm. That is, the tracking error between the output torque and the command torque of the reaction wheel is better than 5E-5 Nm, achieving a better tracking control result.

[0068] Another embodiment of this application provides a calculation device for the compensation torque of a reaction wheel, referring to... Figure 10 As shown, the device 1000 includes: a torque distribution module 1010 configured to calculate the command torque allocated to the reaction wheel in the reaction wheel assembly based on the target value of the attitude control torque; a first calculation module 1020 configured to calculate the actual speed increment of the reaction wheel in the reaction wheel assembly in the current cycle; a second calculation module 1030 configured to calculate the target speed increment of the corresponding reaction wheel based on the command torque allocated to the reaction wheel in the reaction wheel assembly in the current cycle; and a third calculation module 1040 configured to calculate a first difference between the target speed increment and the actual speed increment, and calculate a first compensation torque based on the first difference using a proportional-integral control algorithm.

[0069] In some embodiments, the device 1000 further includes a designation module, which is configured to designate at least one reaction wheel in the reaction wheel assembly as a speed-controlled reaction wheel and the remaining reaction wheels as non-speed-controlled reaction wheels.

[0070] In some embodiments, the mounting vector of at least one speed control reaction wheel is set to... .

[0071] In some embodiments, the apparatus 1000 further includes a smoothing module, which is configured to perform a sliding smoothing calculation based on the first compensation torque of the current period and the first compensation torque of the remaining periods in the sliding window to obtain a second compensation torque.

[0072] In some embodiments, the device 1000 further includes a first update module, which is configured to, after obtaining the second compensation torque of the current period, move the first compensation torque of the current period into the sliding window and move the first compensation torque of the earliest period out of the sliding window.

[0073] In some embodiments, the device 1000 further includes a filtering module configured to perform low-pass filtering based on the second compensation torque and in combination with the second compensation torque of the previous cycle to obtain a third compensation torque.

[0074] In some embodiments, the device 1000 further includes a second update module, which is configured to store the second compensation torque of the current cycle as the second compensation torque value of the previous cycle after obtaining the third compensation torque of the current cycle.

[0075] In some embodiments, the device 1000 further includes a limiting module configured to limit the compensation torque so that the compensation torque does not exceed the maximum compensation torque of the reaction wheel.

[0076] Details of other operations performed by each module in this embodiment can be found in the foregoing embodiments, and will not be elaborated here.

[0077] This embodiment of the device distributes the attitude control torque target into command torques for each reaction wheel, calculates the target speed increment based on the command torque, and calculates the actual speed increment based on the actual measured speed of the reaction wheel. The error between the target speed response and the actual speed response characterizes the influence of frictional torque or loss torque in the current operating state of the reaction wheel. Then, based on this error, a proportional-integral control algorithm is used to calculate the first compensation torque, achieving real-time compensation for the frictional torque of the reaction wheel. This solves the problem of insufficient compensation accuracy of fixed lookup table compensation or equivalent torque compensation under wide speed ranges and time-varying friction conditions, improves the tracking accuracy of the actual output torque of the reaction wheel to the command torque, reduces the impact of frictional torque on the satellite attitude closed-loop control, and enhances the stability and control accuracy of satellite attitude control.

[0078] The device for calculating the compensation torque of a reaction wheel in this embodiment can be a device, or it can be a component, integrated circuit, or chip in a terminal. The device for calculating the compensation torque of a reaction wheel in this embodiment can be a device with an operating system. This operating system can be Android, iOS, or other possible operating systems; this embodiment does not specifically limit its use.

[0079] This application also provides an electronic device, including: a memory for storing programs or instructions executable by a processor; and a processor for executing the programs or instructions to implement the various processes of the above-described method embodiment for calculating the compensation torque of the reaction wheel, and achieving the same technical effect. To avoid repetition, it will not be described again here.

[0080] Figure 11 This is a schematic diagram of an electronic device according to an embodiment of this application. The electronic device 1100 may include an internal communication bus 1101, a processor 1102, a read-only memory (ROM) 1103, a random access memory (RAM) 1104, and a communication port 1105. When applied to a personal computer, the electronic device 1100 may also include a hard disk 1106. The internal communication bus 1101 enables data communication between components of the electronic device 1100. The processor 1102 can perform judgments and issue prompts. In some embodiments, the processor 1102 may consist of one or more processors. The communication port 1105 enables data communication between the electronic device 1100 and external devices. In some embodiments, the electronic device 1100 can send and receive information and data from a network through the communication port 1105. Electronic device 1100 may also include different forms of program storage units and data storage units, such as hard disk 1106, read-only memory (ROM) 1103 and random access memory (RAM) 1104, capable of storing various data files used for computer processing and / or communication, as well as possible programs or instructions executed by processor 1102. The results processed by processor 1102 are transmitted to user equipment through communication port 1105 and displayed on the user interface.

[0081] The above-mentioned method for calculating the reaction wheel compensation torque can be implemented as a computer program, stored in the hard disk 1106, and recorded in the processor 1102 for execution, so as to implement any of the reaction wheel compensation torque calculation methods in this application.

[0082] This application also provides a readable storage medium storing a program or instructions. When the program or instructions are executed by a processor, they implement the various processes of the above-described method for calculating the compensation torque of the reaction wheel and achieve the same technical effect. To avoid repetition, they will not be described again here.

[0083] The processor is the processor in the electronic device described in the above embodiments. The readable storage medium includes computer-readable storage media, such as computer read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0084] A computer-readable medium may contain a propagated data signal containing computer program code, for example, on baseband or as part of a carrier wave. This propagated signal may take various forms, including electromagnetic, optical, and so on, or suitable combinations thereof. A computer-readable medium can be any computer-readable medium other than a computer-readable storage medium, which can be connected to an instruction execution system, apparatus, or device to enable communication, propagation, or transmission of a program for use. The program code located on the computer-readable medium can be propagated through any suitable medium, including radio, cable, fiber optic cable, radio frequency signals, or similar media, or any combination of the above media.

[0085] In some embodiments, numbers describing the quantity of components and attributes are used. It should be understood that such numbers used in the description of embodiments are modified in some examples with the terms "approximately," "approximately," or "generally." Unless otherwise stated, "approximately," "approximately," or "generally" indicates that the numbers are allowed to vary by ±20%. Accordingly, in some embodiments, the numerical parameters used in the specification and claims are approximate values, which may be changed depending on the characteristics required by individual embodiments. In some embodiments, numerical parameters should take into account specified significant digits and employ a general method of digit reservation. Although the numerical ranges and parameters used to confirm their breadth of scope in some embodiments of this application are approximate values, in specific embodiments, such values ​​are set as precisely as feasible.

[0086] Although this application has been described with reference to specific embodiments, those skilled in the art should recognize that the above embodiments are only used to illustrate this application, and various equivalent changes or substitutions can be made without departing from the spirit of this application. Therefore, any changes or modifications to the above embodiments within the essential spirit of this application will fall within the scope of the claims of this application.

Claims

1. A method for calculating the compensating torque of a reaction wheel, characterized in that, include: Calculate the command torque allocated to the reaction wheel in the reaction wheel assembly based on the target value of the attitude control torque; Calculate the actual speed increment of the reaction wheel in the reaction wheel assembly during the current cycle; Calculate the target speed increment of the corresponding reaction wheel based on the command torque allocated to the reaction wheel in the reaction wheel assembly of the current cycle; Calculate the first difference between the target speed increment and the actual speed increment, and calculate the first compensation torque based on the first difference using a proportional-integral control algorithm.

2. The method for calculating the reaction wheel compensation torque as described in claim 1, characterized in that, Also includes: At least one reaction wheel in the reaction wheel assembly is designated as a speed-controlled reaction wheel, and the remaining reaction wheels are designated as non-speed-controlled reaction wheels.

3. The method for calculating the reaction wheel compensation torque as described in claim 2, characterized in that, The installation vector of the at least one speed-regulating reaction wheel is set as follows: .

4. The method for calculating the reaction wheel compensation torque as described in claim 1, characterized in that, Also includes: The second compensation torque is obtained by performing a sliding smoothing calculation based on the first compensation torque of the current cycle and the first compensation torque of the other cycles in the sliding window.

5. The method for calculating the reaction wheel compensation torque as described in claim 4, characterized in that, Also includes: After obtaining the second compensation torque for the current cycle, the first compensation torque for the current cycle is moved into the sliding window, and the first compensation torque for the earliest cycle is moved out of the sliding window.

6. The method for calculating the reaction wheel compensation torque as described in claim 4, characterized in that, Also includes: Based on the second compensation torque and combined with the second compensation torque of the previous cycle, a low-pass filtering process is performed to obtain the third compensation torque.

7. The method for calculating the reaction wheel compensation torque as described in claim 6, characterized in that, Also includes: After obtaining the third compensation torque for the current cycle, the second compensation torque for the current cycle is stored as the second compensation torque value of the previous cycle.

8. The method for calculating the reaction wheel compensation torque as described in claim 1, characterized in that, Also includes: The compensation torque is limited to ensure that it does not exceed the maximum compensation torque of the reaction wheel.

9. A device for calculating the compensating torque of a reaction wheel, characterized in that, include: The torque distribution module is configured to calculate the command torque allocated to the reaction wheel in the reaction wheel assembly based on the target value of the attitude control torque; The first calculation module is configured to calculate the actual speed increment of the reaction wheel in the reaction wheel assembly during the current cycle; The second calculation module is configured to calculate the target speed increment of the corresponding reaction wheel based on the command torque allocated to the reaction wheel in the reaction wheel assembly in the current cycle; The third calculation module is configured to calculate a first difference between the target speed increment and the actual speed increment, and to calculate a first compensation torque based on the first difference using a proportional-integral control algorithm.

10. An electronic device, characterized in that, include: A processor and a memory, the memory storing a program or instructions running on the processor, the program or instructions being executed by the processor to implement the steps of the method for calculating the reaction wheel compensation torque as described in any one of claims 1-8.

11. A readable storage medium, characterized in that, The readable storage medium stores a program or instructions that, when executed by a processor, implement the steps of the method for calculating the reaction wheel compensation torque as described in any one of claims 1-8.

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