Method for designing optimal cruise flight attitude of long-time ring target under multi-constraint condition
By designing the optimal cruise flight attitude under multiple constraints during long-term orbital flight around the target, the problem of unstable attitude control of the probe was solved, attitude stability and satisfaction of multiple constraints were achieved, the impact of attitude control on orbital parameters was reduced, and the smooth implementation of subsequent missions was ensured.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-12
- Publication Date
- 2026-04-14
AI Technical Summary
In probes that orbit targets for extended periods, existing technologies have failed to effectively consider various constraints such as energy, thermal environment, telemetry and control, and gravitational field changes, leading to unstable attitude control and affecting the orbital parameters and accuracy of subsequent missions.
A method for designing the optimal cruise attitude of a long-term circumstantial target under multiple constraints is proposed. By determining the baseline attitude that satisfies the optimal energy and thermal control, and combining the use of jet propulsion and momentum wheel of the attitude control thruster, the attitude control is optimized to meet multiple constraints. The optimal attitude is solved by the gradient ascent method or the Lagrange multiplier method.
It enables the probe to maintain attitude stability during long-term orbital flight around the target, reduces the impact of attitude control on orbital parameters, ensures energy, thermal control and communication safety, and reduces the impact of attitude control on subsequent missions.
Smart Images
Figure CN121857751A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of spacecraft control technology, and in particular relates to a method for designing the optimal cruise flight attitude of a long-term loop target under multiple constraints. Background Technology
[0002] As deep space exploration missions become more multi-objective and involve more on-orbit maneuvers, orbital designs become increasingly complex, and cruise times gradually increase. During missions, probes may need to maintain cruise flight for extended periods. When orbiting target celestial bodies for long durations, the impact of various constraints on the probe must be considered, primarily including the following aspects: 1) Energy Constraints: Solar energy demand persists throughout the entire flight mission and is the most fundamental constraint in the overall flight attitude design. During long-term orbiting of the target, due to changes in the Sun-Probe-Earth angle (SPE angle) and the angle between the Sun vector and the orbital plane, the probe needs to adjust its flight attitude to ensure that the solar panels can charge the required energy, in order to guarantee that the probe's illumination conditions meet its power requirements.
[0003] 2) Thermal environment constraints: Changes in the external heat flow of the target celestial body and changes in the orbital illumination conditions of the probe will cause changes in thermal radiation. The probe needs to adjust its flight attitude to ensure the overall temperature conditions of the probe.
[0004] 3) Measurement and control constraints: The probe needs to maintain communication with the ground throughout the flight. Once the orbit design is determined, the probe's ground measurement and control arc and the relative azimuth of the Earth vector are also determined and will continue to evolve as the flight time increases. During the cruise flight, the flight attitude should be reasonably adjusted according to the changes in the relative azimuth of the ground station to the probe to ensure the safety of ground communication.
[0005] 4) Constraints of Gravitational Field Variation: During the probe's orbit around the target, the target celestial body has an irregular shape and size, resulting in uneven gravitational distribution in different directions. Furthermore, the varying altitudes of the probe's orbital positions relative to the target within one orbital period also cause changes in the gravitational field. These changing gravitational environments generate different gravitational torques. For probes maintaining three-axis attitude stability in inertial space, it is typically necessary to adjust the thrust of the attitude control thrusters or rotate the momentum wheel to reduce the impact of these disturbing torques.
[0006] Traditional deep space exploration missions typically only consider energy, thermal environment, and telemetry constraints, neglecting factors such as short-term changes in the gravitational field of the target celestial body. However, for probes that need to orbit the target for extended periods, when the disturbance torque exceeds a predetermined control threshold, attitude control thrusters are used to generate control torque. Within the control threshold range, momentum wheel rotation is primarily used to provide control torque. When the momentum wheel's angular momentum accumulates to saturation, it will also trigger attitude control thruster unloading, directly generating velocity increments in all axes of the probe. Over long-term orbital evolution, this leads to changes in orbital parameters, directly impacting subsequent stages that require precise orbital configuration, such as timed and precise soft landings and rendezvous and docking within designated areas. Therefore, compared to short-term target orbiting missions, for long-term target orbiting missions while maintaining a predetermined cruise attitude in inertial space, it is necessary to comprehensively consider the energy security and communication security of the probe (ensuring that the channel link gain meets the requirements), the impact of the radiation flow from the surface of the target celestial body on the overall temperature environment of the probe, and the impact of the long-term cumulative evolution of the attitude control thruster jet on subsequent missions when the probe maintains a stable attitude, in order to design the optimal cruise attitude. Summary of the Invention
[0007] The technical problem solved by this invention is to overcome the shortcomings of the prior art and provide a method for designing the optimal cruise flight attitude for long-term circumnavigation targets under multiple constraints. The method designs the optimal cruise flight attitude that can take into account energy security, Earth tracking and control conditions, detector thermal environment, and the influence of changes in the gravitational field of the target celestial body.
[0008] To address the aforementioned technical problems, this invention discloses a method for designing the optimal cruise flight attitude of a long-duration loop target under multiple constraints, comprising: S1, determine the baseline cruise flight attitude that satisfies the optimal energy and optimal thermal control; S2, under the baseline cruise flight attitude, performs the total velocity increment generated by the probe's attitude control thruster jets. The calculation is performed and extrapolated to the target time based on the orbital parameters to evaluate the impact of the probe's attitude control thruster jets on the orbit; if the impact is acceptable, the baseline cruise flight attitude is maintained; if the impact is acceptable, step S3 is executed. S3, under the baseline cruise flight attitude, demonstrates the effective output power of the probe's solar array. Detector temperature and detector telemetry and control link gain The solution; S4, with Minimum Satisfy power balance conditions Meets the safe temperature threshold range The minimum demodulation threshold requirement of the telemetry and control receiver is used as a constraint condition. The optimal cruise attitude evaluation function is solved to obtain the optimal solution of the optimal cruise attitude evaluation function that satisfies all constraints, which is the optimal cruise flight attitude.
[0009] In the above-mentioned method for designing the optimal cruise flight attitude of a long-duration loop target under multiple constraints, the baseline cruise flight attitude that satisfies both energy optimization and thermal control optimization is determined, including: normal vector of the probe's solar array With the probe—Solar Vector The pitch attitude axis pointing at the same time is determined to be the pitch attitude axis pointing that satisfies the energy optimum. The yaw attitude axis pointing when the heat dissipation surface of the probe faces away from the lunar equator is determined to be the yaw attitude axis pointing that satisfies the optimal thermal control. The baseline cruise flight attitude is determined based on the pitch attitude axis pointing that satisfies energy optimization and the yaw attitude axis pointing that satisfies thermal control optimization.
[0010] In the above-mentioned method for designing the optimal cruise flight attitude of a long-duration circling target under multiple constraints, like and If the following equation (1) is satisfied, then it is determined that... and Consistency: ···(1) in, express and The angle between them; If the normal vector of the detector's heat dissipation surface Vector of the Moon's rotation axis If the following equation (2) is satisfied, then the direction in which the heat dissipation surface of the probe faces away from the lunar equator is determined: ···(2) in, express and The angle between them This indicates the orbital inclination angle of the probe.
[0011] In the above-mentioned method for designing the optimal cruise flight attitude of a long-duration loop target under multiple constraints, the following solution is obtained: : The disturbance torque caused by the change in the gravitational field of the target celestial body at different orbital positions is calculated using the following equation (3). : ···(3) in, , and They represent the disturbance torques respectively. The three-axis components; , and These represent the moments of inertia of the three axes, respectively. express Axial product of inertia express Axial product of inertia express Product of axial inertia; This represents the orbital angular velocity of the probe at any orbital position. Indicates pitch angle, Indicates the roll angle; The control torque required for the detector to maintain attitude stability can be calculated using the following equation (4). : ···(4) in, , and They represent Control torque at all times The three-axis components; If the disturbance torque is less than the momentum wheel saturation threshold, it can be calculated using the following formula (5). : ···(5) in, , and These represent the three-axis velocity increments of the probe's attitude control thruster; , and These represent the output thrust of the probe's attitude control thruster. The three-axis components; , and These represent the output torque of the probe's attitude control thruster. The three-axis components; , and These represent the momentum wheel saturation thresholds for the three attitude axes, respectively. Indicates the quality of the detector; If the disturbance torque is not less than the momentum wheel saturation threshold, it can be calculated using the following formula (6). : ···(6) in, , and These represent the target values of the required unloading along the three axial directions when the momentum wheel is saturated.
[0012] In the above-mentioned method for designing the optimal cruise flight attitude of a long-duration loop target under multiple constraints, the following equation (7) is used to obtain the optimal attitude. : ···(7) in, This indicates the area of the probe's solar array exposed to sunlight. Indicates the angle of incidence of the probe's solar array. This indicates the power output efficiency of the detector's solar array.
[0013] In the above-mentioned method for designing the optimal cruise flight attitude of a long-duration loop target under multiple constraints, the following equation (8) is used to obtain the optimal attitude. : ···(8) in, Indicates the gain of the detector's transmitting antenna. Indicates the gain of the detector's receiving antenna. Indicates free space path loss. This indicates the loss caused by atmospheric absorption and antenna polarization mismatch.
[0014] In the above-mentioned method for designing the optimal cruise flight attitude of a long-duration loop target under multiple constraints, the optimal solution of the optimal cruise attitude evaluation function that satisfies all constraints is expressed as follows: ···(9) in, This indicates the total power consumption of the detector during cruise mode; Indicates the lower limit of the safe temperature. Indicates the upper limit of safe temperature. This indicates the minimum demodulation threshold of the telemetry and control receiver. Indicates link margin. This represents the angle between the Earth vector and the telemetry and control antenna. This indicates taking the maximum value. This indicates taking the minimum value. This represents the optimal cruise attitude evaluation function. Indicates the roll angle. Indicates pitch angle, Indicates the yaw angle.
[0015] In the above-mentioned methods for designing the optimal cruise flight attitude of a long-duration circumpolar target under multiple constraints, the gradient ascent method or the Lagrange multiplier method is used for solving the problem. The optimal value.
[0016] The present invention has the following advantages: This invention discloses a method for designing the optimal cruise flight attitude for long-term orbiting of a target under multiple constraints. It solves the problem that the probe needs to adapt to changes in the positions of the sun, earth, and target celestial bodies during long-term orbiting flight. The designed optimal cruise flight attitude can ensure the safety requirements of energy, thermal control, and communication, while minimizing the interference of changes in the gravitational field of the target celestial body on the attitude control system. It also reduces the impact of the additional velocity increment generated by the actuators when the probe is maintaining stable flight in three-axis attitude on orbital parameters and subsequent mission implementation. Attached Figure Description
[0017] Figure 1 This is a flowchart of a method for designing the optimal cruise flight attitude of a long-term loop target under multiple constraints, as described in an embodiment of the present invention. Figure 2 This is a schematic diagram of a detector cruising around a target in an embodiment of the present invention; Figure 3 This is a schematic diagram of the control switch line of the phase plane attitude control thruster for a detector in an embodiment of the present invention. Detailed Implementation
[0018] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments disclosed in the present invention will be described in further detail below with reference to the accompanying drawings.
[0019] Reference Figures 1-2 In this embodiment, the method for designing the optimal cruise flight attitude of a long-duration loop target under multiple constraints includes: S1 determines the baseline cruise flight attitude that satisfies both energy and thermal control optimization.
[0020] In this embodiment, to reduce the time required for subsequent attitude angle traversal and calculation steps, a baseline cruise flight attitude that satisfies both energy and thermal control optimization can be initially determined, and subsequent calculations are performed based on this baseline cruise flight attitude. Specifically: 11) Given the current attitude matrix of the detector The probe-solar vector was obtained by combining the orbital ephemeris calculation. Coordinates within the detector's own system, and the detector-Earth vector. The lower coordinates of the detector's own system.
[0021] 12) The normal vector of the probe's solar array With the probe—Solar Vector The pitch attitude axis pointing at the same time is determined to be the pitch attitude axis pointing that satisfies the energy optimum: like and If the following equation (1) is satisfied, then it is determined that... and Consistency: ···(1) in, express and The angle between them.
[0022] 13) Determine the yaw attitude axis direction when the probe's heat dissipation surface faces away from the lunar equator as the optimal yaw attitude axis direction for thermal control: If the normal vector of the detector's heat dissipation surface Vector of the Moon's rotation axis If the following equation (2) is satisfied, then the direction in which the heat dissipation surface of the probe faces away from the lunar equator is determined: ···(2) in, express and The angle between them; Indicates the orbital inclination angle of the probe; When this occurs, it indicates that the probe is using a forward orbit; When this occurs, it indicates that the probe is using a retrograde orbit.
[0023] 14) Determine the reference cruise flight attitude based on the determined pitch attitude axis pointing that satisfies energy optimization and the yaw attitude axis pointing that satisfies thermal control optimization. The reference attitude matrix corresponds to the reference cruise flight attitude. for: .
[0024] S2, under the baseline cruise flight attitude, performs the total velocity increment generated by the probe's attitude control thruster jets. The calculations are performed and extrapolated to the target time based on the orbital parameters to evaluate the impact of the probe's attitude control thruster jets on the orbit.
[0025] In this embodiment, under the baseline cruise flight attitude, the following calculations are performed: The disturbance torque caused by the change in the gravitational field of the target celestial body at different orbital positions is calculated using the following equation (3). : ···(3) in, , and They represent the disturbance torques respectively. The three-axis components; , and These represent the moments of inertia of the three axes, respectively. express Axial product of inertia express Axial product of inertia express Product of axial inertia; This represents the orbital angular velocity of the probe at any orbital position. Indicates pitch angle, Indicates the roll angle.
[0026] To ensure the stability of the detector's three-axis attitude in inertial space, the change in angular momentum must be zero. The control torque required to maintain the detector's attitude stability can be calculated using the following equation (4). : ···(4) in, , and They represent Control torque at all times The three-axis components.
[0027] like Figure 3 The probe attitude control phase plane attitude control thruster control switch lines shown correspond to the control strategies used in different regions, where: If the control torque required to maintain zero angular momentum is large (i.e., the disturbance torque is less than the momentum wheel saturation threshold), thruster jet control is required. In this case, it can be calculated using the following formula (5). : ···(5) in, , and These represent the three-axis velocity increments of the probe's attitude control thruster; , and These represent the output thrust of the probe's attitude control thruster. The three-axis components; , and These represent the output torque of the probe's attitude control thruster. The three-axis components; , and These represent the momentum wheel saturation thresholds for the three attitude axes, respectively. This indicates the quality of the detector.
[0028] If the control torque required to maintain zero angular momentum is small (i.e., the disturbance torque is not less than the momentum wheel saturation threshold), it is necessary to use the momentum wheel to initiate rotation to provide angular momentum exchange to counteract the disturbance. In this case, it can be calculated by the following formula (6). : ···(6) in, , and These represent the target values of the required unloading along the three axial directions when the momentum wheel is saturated.
[0029] The solution obtained Based on this, extrapolate the orbital parameters to the target time (such as the engine ignition time during the landing and descent phase in subsequent missions) to assess the impact of the probe's attitude control thruster jets on the orbit (such as changes in orbital shape and landing time). If the impact is acceptable, maintain the baseline cruise flight attitude; if the impact is acceptable, proceed to step S3. For example, when the cruise phase is affected by the accumulation of gravitational field disturbance torque, resulting in... A speed greater than 1 m / s would result in a 5 km decrease in orbital altitude or a 10 min deviation in subsequent landing time. If this impact is unacceptable for subsequent mission implementation, steps S3-S4 would be executed to adjust the flight attitude in order to reduce the impact of maintaining long-term attitude stability on the orbit.
[0030] S3, under the baseline cruise flight attitude, demonstrates the effective output power of the probe's solar array. Detector temperature and detector telemetry and control link gain The solution.
[0031] 31) Effective output power of the detector's solar array
[0032] The solution is obtained by solving the following equation (7). : ···(7) in, This indicates the area of the probe's solar array exposed to sunlight. Indicates the angle of incidence of the probe's solar array. This indicates the power output efficiency of the detector's solar array.
[0033] 32) Detector temperature
[0034] Detector temperature and and Related, as indicated below:
[0035] in, express and and Related functions; express and The angle between them.
[0036] 33) Detector telemetry and control link gain
[0037] The solution is obtained by solving the following equation (8). : ···(8) in, Indicates the gain of the detector's transmitting antenna. Indicates the gain of the detector's receiving antenna. and Angle between Earth vector and telemetry antenna The correlation can be determined by the antenna pattern; This represents free-space path loss, which is related to the communication distance between the detector and the ground station, as well as the signal frequency. This indicates the loss caused by atmospheric absorption and antenna polarization mismatch.
[0038] S4, with Minimum Satisfy power balance conditions Meets the safe temperature threshold range The minimum demodulation threshold requirement of the telemetry and control receiver is used as a constraint condition. The optimal cruise attitude evaluation function is solved to obtain the optimal solution of the optimal cruise attitude evaluation function that satisfies all constraints, which is the optimal cruise flight attitude.
[0039] In this embodiment, the optimal solution of the optimal cruise attitude evaluation function that satisfies all constraints is represented as follows: ···(9) in, This indicates the total power consumption of the detector during cruise mode; Indicates the lower limit of the safe temperature. Indicates the upper limit of safe temperature. Indicates the minimum demodulation threshold of the telemetry and control receiver; Indicates link margin, and The correlation can be determined by the antenna pattern; This indicates taking the maximum value. This indicates taking the minimum value; This represents the optimal cruise attitude evaluation function. Indicates the roll angle. Indicates pitch angle, Indicates the yaw angle.
[0040] Preferably, the gradient ascent method or the Lagrange multiplier method can be used to solve the problem. The optimal value. Specifically: ···(10) in, This represents the gradient of a function.
[0041] Given a learning rate Under the given conditions, the solution function can be obtained. The iterative formula for the optimal solution is obtained through multiple iterations, ultimately yielding the optimal solution that satisfies equation (9): ···(11) in, The number of iterations depends on the attitude angle range and the step size; for example, for each axis attitude angle range ∈ [0°, 180°], if the iteration step size is 1°, then iterates step by step. =[(180-0)+1] 3 .
[0042] According to equation (11), the optimal solution satisfying equation (9) is obtained: Optimal roll angle Optimal pitch angle Optimal yaw angle This allows for the determination of the optimal cruise flight attitude that minimizes the impact on the orbit from energy, thermal control, telemetry, and long-duration orbital cruise flight. The optimal reference attitude matrix corresponds to the optimal cruise flight attitude. for: , Indicates according to , , A determined attitude rotation matrix; then based on the optimal reference attitude matrix The on-orbit attitude adjustment has been completed.
[0043] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.
[0044] The contents not described in detail in this specification are common knowledge to those skilled in the art.
Claims
1. A method for designing the optimal cruise flight attitude of a long-duration loop target under multiple constraints, characterized in that, include: S1, determine the baseline cruise flight attitude that satisfies the optimal energy and optimal thermal control; S2, under the baseline cruise flight attitude, performs the total velocity increment generated by the probe's attitude control thruster jets. The calculation is performed and extrapolated to the target time based on the orbital parameters to evaluate the impact of the probe's attitude control thruster jets on the orbit; if the impact is acceptable, the baseline cruise flight attitude is maintained; if the impact is acceptable, step S3 is executed. S3, under the baseline cruise flight attitude, demonstrates the effective output power of the probe's solar array. Detector temperature and detector telemetry and control link gain The solution; S4, with Minimum Satisfy power balance conditions Meets the safe temperature threshold range The minimum demodulation threshold requirement of the telemetry and control receiver is used as a constraint condition. The optimal cruise attitude evaluation function is solved to obtain the optimal solution of the optimal cruise attitude evaluation function that satisfies all constraints, which is the optimal cruise flight attitude.
2. The method for designing the optimal cruise flight attitude of a long-duration loop target under multiple constraints as described in claim 1, characterized in that, Determine the baseline cruise flight attitude that satisfies both energy and thermal control optimization, including: normal vector of the probe's solar array With the probe—Solar Vector The pitch attitude axis pointing at the same time is determined to be the pitch attitude axis pointing that satisfies the energy optimum. The yaw attitude axis pointing when the heat dissipation surface of the probe faces away from the lunar equator is determined to be the yaw attitude axis pointing that satisfies the optimal thermal control. The baseline cruise flight attitude is determined based on the pitch attitude axis pointing that satisfies energy optimization and the yaw attitude axis pointing that satisfies thermal control optimization.
3. The method for designing the optimal cruise flight attitude of a long-duration loop target under multiple constraints as described in claim 2, is characterized in that... like and If the following equation (1) is satisfied, then it is determined that... and Consistency: ···（1） in, express and The angle between them; If the normal vector of the detector's heat dissipation surface Vector of the Moon's rotation axis If the following equation (2) is satisfied, then the direction in which the heat dissipation surface of the probe faces away from the lunar equator is determined: ···（2） in, express and The angle between them This indicates the orbital inclination angle of the probe.
4. The method for designing the optimal cruise flight attitude of a long-duration loop target under multiple constraints as described in claim 1, characterized in that, The solution is obtained as follows: : The disturbance torque caused by the change in the gravitational field of the target celestial body at different orbital positions is calculated using the following equation (3). : ···（3） in, , and They represent the disturbance torques respectively. The three-axis components; , and These represent the moments of inertia of the three axes, respectively. express Product of axial inertia express Product of axial inertia express Axial inertia product; This represents the orbital angular velocity of the probe at any orbital position. Indicates pitch angle, Indicates the roll angle; The control torque required for the detector to maintain attitude stability can be calculated using the following equation (4). : ···（4） in, , and They represent Control torque at all times The three-axis components; If the disturbance torque is less than the momentum wheel saturation threshold, it can be calculated using the following formula (5). : ···（5） in, , and These represent the three-axis velocity increments of the probe's attitude control thruster; , and These represent the output thrust of the probe's attitude control thruster. The three-axis components; , and These represent the output torque of the probe's attitude control thruster. The three-axis components; , and These represent the momentum wheel saturation thresholds for the three attitude axes, respectively. Indicates the quality of the detector; If the disturbance torque is not less than the momentum wheel saturation threshold, it can be calculated using the following formula (6). : ···（6） in, , and These represent the target values of the required unloading along the three axial directions when the momentum wheel is saturated.
5. The method for designing the optimal cruise flight attitude of a long-duration loop target under multiple constraints as described in claim 1, characterized in that, The solution is obtained by solving the following equation (7). : ···（7） in, This indicates the area of the probe's solar array exposed to sunlight. Indicates the angle of incidence of the probe's solar array. This indicates the power output efficiency of the detector's solar array.
6. The method for designing the optimal cruise flight attitude of a long-duration loop target under multiple constraints as described in claim 1, characterized in that, The solution is obtained by solving the following equation (8). : ···（8） in, Indicates the gain of the detector's transmitting antenna. Indicates the gain of the detector's receiving antenna. Indicates free space path loss. This indicates the loss caused by atmospheric absorption and antenna polarization mismatch.
7. The method for designing the optimal cruise flight attitude of a long-duration loop target under multiple constraints as described in claim 1, characterized in that, The optimal solution of the optimal cruise attitude evaluation function that satisfies all constraints is expressed as follows: ···（9） in, This indicates the total power consumption of the detector during cruise mode; Indicates the lower limit of the safe temperature. Indicates the upper limit of safe temperature. This indicates the minimum demodulation threshold of the telemetry and control receiver. Indicates link margin. This represents the angle between the Earth vector and the telemetry and control antenna. This indicates taking the maximum value. This indicates taking the minimum value. This represents the optimal cruise attitude evaluation function. Indicates the roll angle. Indicates pitch angle, Indicates the yaw angle.
8. The method for designing the optimal cruise flight attitude of a long-duration loop target under multiple constraints as described in claim 1, characterized in that, Solve using the gradient ascent method or the Lagrange multiplier method. The optimal value.