Method and apparatus for planning lunar sampling timing, pinpoint landing timing, and takeoff timing

Abstract

This invention discloses a method and apparatus for planning a timed, fixed-point landing and timed takeoff for lunar sampling missions. The method includes: determining the orbital root number and orbital insertion time of the orbit in the first control phase of the lunar sampling mission, as well as the nominal parameters for timed, fixed-point landing and timed takeoff. Based on the nominal parameters, orbital root number, and orbital insertion time, the first control phase is jointly planned with subsequent control phases to obtain a first deviation, and the first deviation is iterated based on a first variable. When the first deviation is less than a convergence threshold, the target variable for the first control phase is determined, allowing the satellite to achieve timed, fixed-point landing and timed takeoff based on the target variables of each control phase. This achieves dynamic joint planning with timed, fixed-point landing and timed takeoff as the final goal for each control phase, effectively improving the mission's control reconfiguration capability, avoiding additional control operations, and reducing resource consumption.

Description

Technical Field

[0001] This invention relates to the field of aerospace, and in particular to a method and apparatus for planning lunar sampling, timing, landing, and takeoff. Background Technology

[0002] Landing and takeoff control is one of the risks and technical challenges faced by extraterrestrial exploration missions, and it has always been a hot topic of research for scholars and engineers both at home and abroad. The flight practice in the later stages of the Apollo program showed that the probe could accurately land at a predetermined location on the lunar surface, achieving a fixed-point landing.

[0003] The entire flight process of the lunar sample return mission includes launch, Earth-Moon transfer, lunar braking, lunar orbit, powered descent, lunar surface operations, powered ascent, rendezvous and docking, Earth-Moon transfer, and reentry and recovery. Many scholars both domestically and internationally have conducted in-depth research on lunar landing trajectory design methods, including adjusting the number of lunar orbits and the lunar orbital plane to aim at the longitude of the predetermined landing point, and using velocity increments and orbital maneuvers within the lunar descent plane to aim at the latitude of the predetermined landing point and the altitude of the powered descent point. Adjusting the lunar orbital plane can be achieved by adjusting the right ascension of the ascending node and correcting the orbital inclination. However, all these methods require additional control and resource consumption.

[0004] Therefore, how to achieve scheduled landings and takeoffs while avoiding additional control and reducing resource consumption is a problem that urgently needs to be solved. Summary of the Invention

[0005] This invention provides a method and apparatus for planning lunar sampling, timing, landing, and takeoff. It enables dynamic joint planning of each control operation from the first mid-course correction during the Earth-Moon transfer phase to the final orbit reduction before landing, with timing, landing, and takeoff as the ultimate goal. This effectively improves the mission's control reconfiguration capability, avoids additional control, and reduces resource consumption.

[0006] In a first aspect, embodiments of the present invention provide a method for planning lunar sampling, timing, location, landing, and takeoff, including:

[0007] For the first control phase of the lunar sampling mission, the orbital six-root number and orbit insertion time of the orbit in the first control phase are determined, as well as the nominal parameters for timed landing and timed takeoff in the lunar sampling mission. The orbital six-root number is a parameter required to describe the satellite's movement in Kepler orbit, and the nominal parameters include nominal landing time, nominal landing site, and nominal takeoff time.

[0008] Based on the nominal parameters, the orbital six-point number, and the orbit insertion time, the first control phase is jointly planned with the subsequent control phase in the lunar sampling mission to obtain a first deviation, and the first deviation is iterated based on a first variable; the first deviation is the deviation between the satellite and the nominal parameters when the satellite lands and takes off on the moon, and the first variable is a time- and / or orbital plane-related variable in the first control phase and the subsequent control phase in the lunar sampling mission.

[0009] When the first deviation is less than the convergence threshold, the target variable for the first control phase is determined so that the satellite can achieve scheduled landing and takeoff based on the target variables for each control phase.

[0010] In the above technical solution, the lunar sampling mission includes multiple control phases. For the first control phase, it is first necessary to determine the orbital root numbers and insertion time of the current orbit. The orbital root numbers are parameters required to describe the satellite's motion in a Keplerian orbit, specifically including the semi-major axis, eccentricity, orbital inclination, ascending node longitude, perigee argument, and true anomaly. Next, the nominal parameters for timed landing and takeoff in the lunar sampling mission are determined. Then, based on the nominal parameters, the orbital root numbers of the orbit in the first control phase, and the insertion time, the first control phase and subsequent control phases are jointly planned to obtain the first deviation. The first deviation is the deviation between the satellite's lunar landing and takeoff and the nominal parameters. The nominal parameters include the planned landing time, landing site, and takeoff site. Therefore, the first deviation can include landing time deviation, landing site deviation, and takeoff site deviation. Then, the first deviation is iterated based on the first variable. The landing time deviation in the first deviation is related to orbital time, while the landing location deviation and takeoff location deviation are related to the orbital plane. Therefore, the first variable is the time- and / or orbital plane-related variable in the first control phase and subsequent control phases of the lunar sampling mission. Finally, when the first deviation iterates to less than the convergence threshold, the target variable for the first control phase is determined. After each control phase completes the above process and obtains the target variables for each control phase, a timed and fixed-point landing and takeoff can be achieved based on the target variables of each control phase. This achieves dynamic joint planning for each control phase, from the first mid-course correction during the Earth-Moon transfer segment to the last orbital descent before landing, with a timed and fixed-point landing and takeoff as the ultimate goal. This effectively improves the mission's control reconfiguration capability, avoids additional control, and reduces resource consumption.

[0011] Optionally, the control phase of the lunar sampling mission includes: mid-course correction, first lunar braking, second lunar braking, third lunar braking, first lunar orbit descent, second lunar orbit descent, orbit-return combination phasing, powered descent, and lunar surface takeoff.

[0012] Optionally, based on the nominal parameters, the number of orbital elements, and the orbital insertion time, the first control phase is jointly planned with the subsequent control phases in the lunar sampling mission to obtain a first deviation, and the first deviation is iterated based on a first variable, including:

[0013] For the mid-course correction control phase in the lunar sampling mission, based on the nominal parameters, the number of orbital elements and the entry time of the orbit in which the mid-course correction control phase is located, the mid-course correction control phase is jointly planned with the first lunar braking, second lunar braking, third lunar braking, first lunar orbit descent, second lunar orbit descent, orbit return combination phasing, powered descent and lunar surface takeoff control phases in the lunar sampling mission, to obtain the landing time deviation, the landing longitude deviation and the takeoff longitude deviation;

[0014] Based on the differential correction algorithm, the landing time deviation, the landing longitude deviation, and the takeoff longitude deviation are iterated according to the mid-course correction orbit inclination angle, the yaw angle of the three lunar brakings, and the semi-major axis of the target orbit after the third lunar braking.

[0015] Optionally, based on the nominal parameters, the number of orbital elements, and the orbital insertion time, the first control phase is jointly planned with the subsequent control phases in the lunar sampling mission to obtain a first deviation, and the first deviation is iterated based on a first variable, including:

[0016] For the first lunar braking control phase in the lunar sampling mission, based on the nominal parameters, the number of orbital elements and the entry time of the orbit in the first lunar braking control phase, the first lunar braking control phase is jointly planned with the second lunar braking, third lunar braking, first lunar orbit descent, second lunar orbit descent, orbit return combination phasing, powered descent and lunar surface takeoff control phases in the lunar sampling mission, to obtain the landing time deviation, the landing longitude deviation and the takeoff longitude deviation;

[0017] Based on the differential correction algorithm, the landing time deviation, the landing longitude deviation, and the takeoff longitude deviation are iterated according to the yaw angle of the first lunar braking, the yaw angle of the second and third lunar braking, and the semi-major axis of the target orbit after the third lunar braking.

[0018] Optionally, based on the nominal parameters, the number of orbital elements, and the orbital insertion time, the first control phase is jointly planned with the subsequent control phases in the lunar sampling mission to obtain a first deviation, and the first deviation is iterated based on a first variable, including:

[0019] For the second lunar braking control phase in the lunar sampling mission, based on the nominal parameters, the number of orbital elements and the entry time of the orbit in which the second lunar braking control phase is located, the second lunar braking control phase is jointly planned with the third lunar braking, the first lunar orbit descent, the second lunar orbit descent, the orbit-return combination phasing, the powered descent and the lunar surface takeoff control phases in the lunar sampling mission, to obtain the landing time deviation, the landing longitude deviation and the takeoff longitude deviation;

[0020] Based on the differential correction algorithm, the landing time deviation, the landing longitude deviation, and the takeoff longitude deviation are iterated according to the yaw angle of the second lunar braking, the yaw angle of the third lunar braking, and the semi-major axis of the target orbit after the third lunar braking.

[0021] Optionally, based on the nominal parameters, the number of orbital elements, and the orbital insertion time, the first control phase is jointly planned with the subsequent control phases in the lunar sampling mission to obtain a first deviation, and the first deviation is iterated based on a first variable, including:

[0022] For the third lunar braking control phase in the lunar sampling mission, based on the nominal parameters, the number of orbital elements and the entry time of the orbit in which the third lunar braking control phase is located, the third lunar braking control phase is jointly planned with the first lunar orbit descent, the second lunar orbit descent, the orbit-return combination phasing, the powered descent and the lunar surface takeoff control phase in the lunar sampling mission, to obtain the landing time deviation, the landing longitude deviation and the takeoff longitude deviation;

[0023] Based on the differential correction algorithm, the landing time deviation, the landing longitude deviation, and the takeoff longitude deviation are iterated according to the yaw angle of the third lunar braking, the yaw angle of the two lunar orbit descents, and the semi-major axis of the target orbit after the third lunar braking.

[0024] Optionally, based on the nominal parameters, the number of orbital elements, and the orbital insertion time, the first control phase is jointly planned with the subsequent control phases in the lunar sampling mission to obtain a first deviation, and the first deviation is iterated based on a first variable, including:

[0025] For the first lunar orbit descent control phase in the lunar sampling mission, based on the nominal parameters, the number of orbital elements and the entry time of the orbit in the first lunar orbit descent control phase, the first lunar orbit descent control phase is jointly planned with the second lunar orbit descent and powered descent control phases in the lunar sampling mission to obtain the descent longitude deviation.

[0026] Based on the differential correction algorithm, the descent longitude deviation is iterated according to the yaw angle of the two lunar descent orbits.

[0027] Optionally, based on the nominal parameters, the number of orbital elements, and the orbital insertion time, the first control phase is jointly planned with the subsequent control phases in the lunar sampling mission to obtain a first deviation, and the first deviation is iterated based on a first variable, including:

[0028] For the second lunar orbit descent control phase in the lunar sampling mission, based on the nominal parameters, the number of orbital elements and the entry time of the orbit in the second lunar orbit descent control phase, the second lunar orbit descent control phase is jointly planned with the powered descent control phase in the lunar sampling mission to obtain the descent longitude deviation.

[0029] Based on the differential correction algorithm, the descent longitude deviation is iterated according to the yaw angle of the second lunar descent orbit.

[0030] Secondly, embodiments of the present invention provide an apparatus for planning lunar sampling, timing, landing, and takeoff, comprising:

[0031] The acquisition module is used to determine the orbital six-root number and orbit insertion time of the orbit in the first control phase of the lunar sampling mission, as well as the nominal parameters for timed landing and takeoff in the lunar sampling mission. The orbital six-root number is a parameter required to describe the satellite's movement in Kepler orbit, and the nominal parameters include nominal landing time, nominal landing site, and nominal takeoff time.

[0032] The processing module is used to jointly plan the first control phase and the subsequent control phase in the lunar sampling mission based on the nominal parameters, the number of orbital six elements, and the orbit insertion time, to obtain a first deviation, and to iterate the first deviation based on a first variable; the first deviation is the deviation between the satellite and the nominal parameters when the satellite lands and takes off on the moon, and the first variable is a time- and / or orbital plane-related variable in the first control phase and the subsequent control phase in the lunar sampling mission.

[0033] When the first deviation is less than the convergence threshold, the target variable for the first control phase is determined so that the satellite can achieve scheduled landing and takeoff based on the target variables for each control phase.

[0034] Optionally, the control phase of the lunar sampling mission includes: mid-course correction, first lunar braking, second lunar braking, third lunar braking, first lunar orbit descent, second lunar orbit descent, orbit-return combination phasing, powered descent, and lunar surface takeoff.

[0035] Optionally, the processing module is specifically used for:

[0036] For the mid-course correction control phase in the lunar sampling mission, based on the nominal parameters, the number of orbital elements and the entry time of the orbit in which the mid-course correction control phase is located, the mid-course correction control phase is jointly planned with the first lunar braking, second lunar braking, third lunar braking, first lunar orbit descent, second lunar orbit descent, orbit return combination phasing, powered descent and lunar surface takeoff control phases in the lunar sampling mission, to obtain the landing time deviation, the landing longitude deviation and the takeoff longitude deviation;

[0037] Based on the differential correction algorithm, the landing time deviation, the landing longitude deviation, and the takeoff longitude deviation are iterated according to the mid-course correction orbit inclination angle, the yaw angle of the three lunar brakings, and the semi-major axis of the target orbit after the third lunar braking.

[0038] Optionally, the processing module is specifically used for:

[0039] For the first lunar braking control phase in the lunar sampling mission, based on the nominal parameters, the number of orbital elements and the entry time of the orbit in the first lunar braking control phase, the first lunar braking control phase is jointly planned with the second lunar braking, third lunar braking, first lunar orbit descent, second lunar orbit descent, orbit return combination phasing, powered descent and lunar surface takeoff control phases in the lunar sampling mission, to obtain the landing time deviation, the landing longitude deviation and the takeoff longitude deviation;

[0040] Based on the differential correction algorithm, the landing time deviation, the landing longitude deviation, and the takeoff longitude deviation are iterated according to the yaw angle of the first lunar braking, the yaw angle of the second and third lunar braking, and the semi-major axis of the target orbit after the third lunar braking.

[0041] Optionally, the processing module is specifically used for:

[0042] For the second lunar braking control phase in the lunar sampling mission, based on the nominal parameters, the number of orbital elements and the entry time of the orbit in which the second lunar braking control phase is located, the second lunar braking control phase is jointly planned with the third lunar braking, the first lunar orbit descent, the second lunar orbit descent, the orbit-return combination phasing, the powered descent and the lunar surface takeoff control phases in the lunar sampling mission, to obtain the landing time deviation, the landing longitude deviation and the takeoff longitude deviation;

[0043] Based on the differential correction algorithm, the landing time deviation, the landing longitude deviation, and the takeoff longitude deviation are iterated according to the yaw angle of the second lunar braking, the yaw angle of the third lunar braking, and the semi-major axis of the target orbit after the third lunar braking.

[0044] Optionally, the processing module is specifically used for:

[0045] For the third lunar braking control phase in the lunar sampling mission, based on the nominal parameters, the number of orbital elements and the entry time of the orbit in which the third lunar braking control phase is located, the third lunar braking control phase is jointly planned with the first lunar orbit descent, the second lunar orbit descent, the orbit-return combination phasing, the powered descent and the lunar surface takeoff control phase in the lunar sampling mission, to obtain the landing time deviation, the landing longitude deviation and the takeoff longitude deviation;

[0046] Based on the differential correction algorithm, the landing time deviation, the landing longitude deviation, and the takeoff longitude deviation are iterated according to the yaw angle of the third lunar braking, the yaw angle of the two lunar orbit descents, and the semi-major axis of the target orbit after the third lunar braking.

[0047] Optionally, the processing module is specifically used for:

[0048] For the first lunar orbit descent control phase in the lunar sampling mission, based on the nominal parameters, the number of orbital elements and the entry time of the orbit in the first lunar orbit descent control phase, the first lunar orbit descent control phase is jointly planned with the second lunar orbit descent and powered descent control phases in the lunar sampling mission to obtain the descent longitude deviation.

[0049] Based on the differential correction algorithm, the descent longitude deviation is iterated according to the yaw angle of the two lunar descent orbits.

[0050] Optionally, the processing module is specifically used for:

[0051] For the second lunar orbit descent control phase in the lunar sampling mission, based on the nominal parameters, the number of orbital elements and the entry time of the orbit in the second lunar orbit descent control phase, the second lunar orbit descent control phase is jointly planned with the powered descent control phase in the lunar sampling mission to obtain the descent longitude deviation.

[0052] Based on the differential correction algorithm, the descent longitude deviation is iterated according to the yaw angle of the second lunar descent orbit.

[0053] Thirdly, embodiments of the present invention also provide a computer device, comprising:

[0054] Memory, used to store program instructions;

[0055] The processor is used to call the program instructions stored in the memory and execute the above-mentioned method for scheduled lunar sampling, landing, and takeoff according to the obtained program.

[0056] Fourthly, embodiments of the present invention also provide a computer-readable storage medium storing computer-executable instructions for causing a computer to execute the above-described method for planning lunar sampling, timing, landing, and takeoff.

[0057] Fifthly, embodiments of the present invention also provide a computer program product, the computer program product including an executable program, which is executed by a processor to perform the above-described method for planning lunar sampling, timing, landing, and takeoff. Attached Figure Description

[0058] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0059] Figure 1 A schematic diagram of a detector architecture provided in an embodiment of the present invention;

[0060] Figure 2 This is a schematic diagram illustrating a type of lunar sample return mission provided by an embodiment of the present invention;

[0061] Figure 3 This invention provides a schematic diagram of a lunar sampling landing and takeoff in a forward orbit in the northern hemisphere of the moon, as provided in an embodiment of the invention.

[0062] Figure 4 This invention provides a schematic diagram of a lunar sampling landing and takeoff in a forward orbit in the southern hemisphere of the moon, as provided in an embodiment of the invention.

[0063] Figure 5 This invention provides a schematic diagram of a retrograde lunar sampling landing and takeoff in the northern hemisphere.

[0064] Figure 6 This invention provides a schematic diagram of a retrograde lunar southern hemisphere sampling landing and takeoff.

[0065] Figure 7 A schematic diagram of a system architecture provided for an embodiment of the present invention;

[0066] Figure 8 A flowchart illustrating a method for planning a lunar sampling, timing, and takeoff timed landing, provided by an embodiment of the present invention;

[0067] Figure 9 This is a schematic diagram of a device for planning lunar sampling, timing, landing, and takeoff, provided as an embodiment of the present invention. Detailed Implementation

[0068] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0069] The application scenarios described in this application are for the purpose of more clearly illustrating the technical solutions protected by the embodiments of this application, and do not constitute a limitation on the technical solutions provided by the embodiments of this application. Those skilled in the art will understand that with the emergence of new application scenarios, the technical solutions provided by the embodiments of this application are also applicable to similar technical problems. The terms "first" and "second" in the specification, claims, and accompanying drawings of this application are used to distinguish different objects, not to describe a specific order. In the description of this application, unless otherwise stated, "multiple" means two or more.

[0070] Before introducing the method for planning lunar sampling, timing, landing, and takeoff according to the embodiments of this application, the terms and background technology involved in the embodiments of this application will be introduced below for ease of understanding.

[0071] Landing and takeoff control is one of the risks and technical challenges faced by extraterrestrial exploration missions, and has always been a research hotspot for scholars and engineers both domestically and internationally. The later stages of the Apollo program demonstrated that probes could accurately land at predetermined locations on the lunar surface, achieving a pinpoint landing. Under the guidance of China's three-step lunar exploration strategy of "orbiting," "landing," and "returning," research on pinpoint landing control began early and is relatively comprehensive. Common orbital maneuvering strategies for achieving pinpoint landing include orbital adjustments, phasing orbits, and orbital plane adjustments. Chang'e-4 was the first to propose a soft landing on the far side of the moon. Compared to the Chang'e-3 mission, the landing area was significantly reduced, and the control constraints imposed by the far side of the moon made the flight program more tightly scheduled, thus creating the mission requirement for timed and pinpoint landing control. To address this problem, scholars, based on the evolutionary characteristics of orbital deviation with perturbations and combining the advantages of analytical and numerical methods, proposed a semi-analytical solution method for timed and fixed-point landing control, achieving rapid and accurate solutions for lunar landing control parameters. They also proposed a full-process orbital control design method, performing segmented design and joint planning for the entire orbital control process, including Earth-Moon transfer, lunar braking, lunar orbit descent, and powered descent, ensuring a timed and fixed-point lunar landing under orbital deviation conditions. Chang'e 5, as the final mission of the third phase of lunar exploration, aimed to achieve the goal of "returning home." As one of the most complex and challenging missions in China's space program at the time, the fixed sampling area and sampling time imposed even stricter requirements for timed and fixed-point landing. Furthermore, to minimize fuel consumption for orbital plane correction during remote guidance, a timed coplanar takeoff requirement was proposed for the first time. To address this problem, scholars established an analytical model for calculating the takeoff azimuth angle and initial takeoff time, derived the mapping relationship between the remote guidance endpoint orbital plane deviation and the orbital parameter deviation at the entry point, and established an iterative solution model, achieving a "virtual" coplanar takeoff.

[0072] Chang'e 6, the fourth phase of lunar exploration, had an upgraded mission objective: the first sample return from the far side of the moon. The sampling area was significantly smaller than that of Chang'e 5. Due to the obstruction from the far side of the moon, the mission incorporated the Queqiao-2 relay satellite, operating in a lunar frozen orbit, to provide telemetry and control support during the critical phases of powered descent, lunar surface sampling, and lunar surface takeoff. The limitations of the sampling area and the addition of the relay satellite placed higher demands on the timing and location control for landing and takeoff. Furthermore, the change in the sampling area's location and the first use of a retrograde lunar orbit altered the geometric relationships of powered descent and lunar surface takeoff, meaning the timing and location control algorithm could not be simply inherited from Chang'e 5 and needed to be re-derived and designed.

[0073] Lunar sample return missions based on lunar orbit rendezvous and docking typically include an orbiter, lander, ascent vehicle, and return capsule, such as... Figure 1As shown. The orbiter is used for maneuver control during processes such as Earth-Moon transfer, lunar braking, lunar orbit waiting, lunar-Earth injection, and lunar-Earth transfer. The lander is used for powered descent and lunar orbit descent control before powered descent. The ascent vehicle is used for lunar surface takeoff and rendezvous and docking with the orbiter-returner combination. The return vehicle is used to carry lunar samples and return to Earth.

[0074] Taking the Chang'e-5 mission as an example, the return flight process based on lunar orbit rendezvous and docking can generally be divided into 11 stages: launch, Earth-Moon transfer, lunar braking, lunar orbit flight, powered descent, lunar surface operation, lunar surface takeoff, rendezvous and docking, lunar orbit waiting, Earth-Moon transfer, and reentry and recovery. The following describes some of these stages and their associated control mechanisms.

[0075] The Earth-Moon transfer phase, from the separation of the probe from the launch vehicle until reaching the lunar perigee, takes approximately 5 days. Three mid-course correction control maneuvers are typically reserved during the transfer; the timing of these maneuvers is determined based on telemetry and control constraints, and the strategy for all three maneuvers is identical. The planning variable X includes three directional velocity increment components [Δv]. xi ,Δv yi ,Δv zi ], where i is the number of corrections made along the way. The target variable Y includes [T p-1 i p-1 ,h p-1 ], where T p-1 The moment when i first reaches the perigee p-1 h is the orbital inclination angle. p-1 This is the altitude of the perigee.

[0076] The lunar braking phase begins at the lunar periapsis and continues until the probe enters a circular lunar orbit. After reaching the lunar periapsis, the probe undergoes several braking maneuvers (taking three braking maneuvers as an example) to finally enter a circular lunar orbit at an altitude of approximately 200 km. Lunar braking control is primarily in-plane control, but the orbital plane can be corrected by setting the yaw angle. The planning variable X includes [Δv...]. T-LOI-i ], where Δv T-LOI-i Let be the tangential component of the near-lunar braking speed increment, and ... T-i ], where a T-i The semi-major axis of the target after the i-th near-lunar braking control.

[0077] The lunar orbit phase begins when the probe enters its lunar circular orbit and ends before powered descent. During this phase, the probe will separate into an orbital reentry assembly and a landing assembly. The former will remain in lunar orbit and, when appropriate, will undergo phasing control (details in the literature, not elaborated here) to create target orbital conditions for ascent vehicle takeoff and rendezvous with the remote guidance system. The latter will undergo lunar descent control to create entry conditions for powered descent. Lunar descent is generally performed in two stages. The first stage optimizes the pitch angle at a fixed time and for a fixed duration to minimize the lunar perihelion altitude. The second stage targets the powered descent point parameters, namely the lunar perihelion argument and altitude during the powered descent orbit. Both descents are primarily in-plane control, but the orbital plane can be corrected by setting the yaw angle. The first lunar descent control is mainly used for test firing of the powered descent engine and is not planned; the planning focuses on the second lunar descent. The planning variable X includes [Δv...]. t-DM-2 ,Δv r-DM-2 ], where Δv t-DM-2 For the tangential component of the second lunar orbital descent velocity increment, Δv r-DM-2 This represents the radial component of the second lunar orbital descent velocity increment. The target variable Y includes [h] p-d ,ω p-d ], where h p-d ω represents the perigee altitude corresponding to the point of dynamic descent. p-d This is the near-lunar argument corresponding to the point of dynamic descent.

[0078] The powered descent phase begins at the lunar perihelion during the powered descent phase and ends at the lunar surface. Powered descent control is autonomously implemented by the landing craft and is primarily in-plane control, established through analytical geometric relationships between the powered descent point, range, and landing point.

[0079] The lunar work segment begins when the landing assembly touches the lunar surface and continues until sample collection, packaging, and the ascent vehicle is ready for takeoff.

[0080] The lunar takeoff phase begins when the ascent vehicle lifts off the lunar surface and ends when it enters orbit. Lunar takeoff control is autonomously implemented by the ascent vehicle, establishing an analytical geometric relationship with the orbital insertion point through constraints on the launch direction, takeoff point, and range.

[0081] The rendezvous and docking phase involves the ascent vehicle entering orbit and completing the rendezvous and docking. This phase includes several remote guidance control maneuvers for the ascent vehicle, which will not be detailed here.

[0082] Other stages are not closely related to the algorithm presented in this paper and will not be detailed here; please refer to the literature for specific information. The table below summarizes the control strategies employed for different stages of the lunar return mission.

[0083] Table 1 Planning strategies for control at different stages

[0084] Serial Number control Planning variables Target variable 1 TCM-1 / 2 / 3 <![CDATA[Δv x ,Δv y ,Δv z ]]> <![CDATA[T p_1 ,i p_1 ,h p_1 ]]> 2 LOI-1 <![CDATA[Δv T_LOI-1 ]]> <![CDATA[a T-1 ]]> 3 LOI-2 <![CDATA[Δv T_LOI-2 ]]> <![CDATA[a T-2 ]]> 4 LOI-3 <![CDATA[Δv T_LOI-3 ]]> <![CDATA[a T-3 ]]> 5 HYXZ <![CDATA[Δv T_hyxz ]]> <![CDATA[a T-hyxz ]]> 6 DM-1 / 2 <![CDATA[Δv t_DM-2 ,Δv r_DM-2 ]]> <![CDATA[h p_d ,oh p_d ]]>

[0085] Because the Moon rotates from west to east, to ensure that the powered descent and lunar takeoff are on the same plane, the instantaneous lunar-solid system landing point is located west of the takeoff point. Based on the type of lunar orbit and the distribution of landing points, lunar sample return missions based on lunar orbit rendezvous and docking can be divided into four types: prograde lunar northern hemisphere sampling, prograde lunar southern hemisphere sampling, retrograde lunar northern hemisphere sampling, and retrograde lunar southern hemisphere sampling. For example... Figure 2 As shown, four types of schematic diagrams are given. Point D in the diagram is the landing point, and point L is the takeoff point. The longitude difference between points D and L is determined by the duration of lunar surface work.

[0086] Lunar sample return based on lunar orbit rendezvous and docking requires the lunar orbit to pass through the landing point at both the landing and takeoff times. Taking lunar northern hemisphere sampling in a prograde orbit as an example, a schematic diagram of timed landing and takeoff in the instantaneous equatorial inertial frame at the lunar center is given, as follows. Figure 3 As shown in the figure. The figure shows the two-dimensional nadir trajectory on the lunar surface. D is the landing point at the moment of landing, L is the landing point at the moment of takeoff, G is the ascending node, H is the descending node, arc GH is the nadir trajectory of the probe on the lunar surface, arc NE is the meridian passing through the landing point, arc NF is the meridian passing through the takeoff point, and i is the lunar orbital inclination. Point A is the powered descent point, point N is the North Pole, and point S is the South Pole.

[0087] According to spherical trigonometry, the longitude λ of the landing point at the moment of target landing is... d and the longitude λ of the landing point at the time of takeoff l The following relationship exists:

[0088]

[0089] In the formula, Ω m Let _i_ be the longitude of the ascending node of the orbit at the moment of dynamic descent, and _i_ be the inclination of the orbit at the moment of dynamic descent. This represents the latitude of the landing point.

[0090] Due to the target landing point time T d Departure time T l The latitude and longitude of the target landing point are both fixed values. The difference in longitude between the landing point and the target at the landing time and takeoff time is as follows:

[0091]

[0092] A schematic diagram of a sampling landing and takeoff operation in the lunar southern hemisphere along a prograde orbit, as shown below. Figure 4 As shown. For sampling the southern hemisphere of the moon in a prograde orbit, The difference in longitude between the landing point and the target at the landing time and takeoff time is as follows:

[0093]

[0094] A schematic diagram of a sampling landing and takeoff operation in the lunar northern hemisphere on a retrograde orbit, as shown below. Figure 5 As shown. For sampling the northern hemisphere of the moon in a retrograde orbit, The longitude difference between the landing point and the target at the landing time and takeoff time is:

[0095]

[0096] A schematic diagram of a sampling landing and takeoff operation in the lunar southern hemisphere on a retrograde orbit, as shown below. Figure 6 As shown. For sampling the southern hemisphere of the moon in a retrograde orbit, The longitude difference between the landing point and the target at the landing time and takeoff time is:

[0097]

[0098] Scheduled landing and takeoff refer to controlling the upper assembly to descend and land at a predetermined point at a predetermined time, and controlling the ascender to take off at a predetermined time, while maintaining a "virtual" coplanarity with the orbit of the orbital return assembly. Based on the above analysis, the control objective for scheduled landing and takeoff can be described as follows:

[0099]

[0100] In the formula, ΔT d Δλ represents the deviation between the lunar landing time and the nominal lunar landing time. d Δλ represents the deviation between the actual landing point longitude and the nominal landing point longitude. l To account for the deviation between the orbiter's ground point longitude and landing point longitude at the nominal takeoff time when the orbiter is "virtually" coplanar.

[0101] Figure 7 An exemplary system architecture applicable to an embodiment of the present invention is shown. The system architecture includes a server 700, which may include a processor 710, a communication interface 720, and a memory 730.

[0102] The communication interface 720 is used to transmit data with the satellite.

[0103] The processor 710 is the control center of the server 700, connecting various parts of the server 700 through various interfaces and routes. It performs various functions and processes data by running or executing software programs and / or modules stored in the memory 730, and by calling data stored in the memory 730. Optionally, the processor 710 may include one or more processing units.

[0104] The memory 730 can be used to store software programs and modules. The processor 710 executes various functional applications and data processing by running the software programs and modules stored in the memory 730. The memory 730 may mainly include a program storage area and a data storage area. The program storage area may store the operating system, at least one application program required for a function, etc.; the data storage area may store data created according to business processing, etc. In addition, the memory 730 may include high-speed random access memory, and may also include non-volatile memory, such as at least one disk storage device, flash memory device, or other volatile solid-state storage device.

[0105] It should be noted that the above Figure 7 The structure shown is merely an example, and the embodiments of the present invention are not limited thereto.

[0106] Based on the above description Figure 8 An exemplary flowchart of a method for planning lunar sampling, timing, landing, and takeoff is provided in an embodiment of the present invention. This process can be executed by a device for planning lunar sampling, timing, landing, and takeoff.

[0107] like Figure 8 As shown, the process specifically includes:

[0108] Step 810: For the first control phase of the lunar sampling mission, determine the orbital six-axis number and orbit insertion time of the orbit in which the first control phase is located, as well as the nominal parameters for timed landing and timed takeoff in the lunar sampling mission. The orbital six-axis number is a parameter required to describe the satellite's movement in Kepler orbit, and the nominal parameters include nominal landing time, nominal landing site, and nominal takeoff time.

[0109] In this embodiment of the invention, the lunar sampling mission includes multiple control phases. For the first control phase, it is first necessary to determine the orbital root numbers and orbit insertion time of the orbit in which the first control phase is located. The orbital root numbers are parameters required to describe the satellite's motion in a Keplerian orbit, including: semi-major axis, eccentricity, orbital inclination, ascending node ecliptic longitude, perigee argument, and true anomaly. Specifically, the semi-major axis is half the major axis of the elliptical orbit, sometimes considered as the average orbital radius; eccentricity is a measure of the flatness of the ellipse, defined as the ratio of the distance between the two foci to the length of the major axis; orbital inclination is the angle between the orbital plane and the equatorial plane; ascending node ecliptic longitude is the point where the satellite crosses the equator as it moves from the Southern Hemisphere to the Northern Hemisphere, and the angle between the ascending node and the vernal equinox with respect to the Earth's center is called the ascending node right ascension; perigee argument is the angle measured counterclockwise from the ascending node along the planetary orbit to the perigee; and true anomaly is the angle between the orbital perigee and the satellite's position vector at a given moment. The above parameters can be used to represent the specific position and velocity of the object through trigonometric function operations.

[0110] Then, after determining the orbital root number and orbital insertion time, it is also necessary to determine the nominal parameters for the scheduled landing and takeoff in the lunar sampling mission. The nominal parameters include the nominal landing time, nominal landing site, and nominal takeoff time.

[0111] Step 820: Based on the nominal parameters, the number of orbital elements, and the orbit insertion time, jointly plan the first control phase with the subsequent control phase in the lunar sampling mission to obtain a first deviation, and iterate the first deviation based on a first variable; the first deviation is the deviation between the satellite and the nominal parameters when the satellite lands and takes off on the moon, and the first variable is a time- and / or orbital plane-related variable in the first control phase and the subsequent control phase in the lunar sampling mission.

[0112] In this embodiment of the invention, after determining the orbital root number and orbit insertion time of the orbit containing the first control phase, the first control phase is jointly planned with its subsequent control phases in the lunar sampling mission based on the nominal parameters, orbital root number, and orbit insertion time to obtain the first deviation. The first deviation can be the deviation between the satellite's landing and takeoff on the moon and the nominal parameters. The nominal parameters include the planned landing time, landing site, and takeoff site. Therefore, the first deviation can include landing time deviation, landing site deviation, and takeoff site deviation. It can be understood that since the landing site and takeoff site are at the same latitude, the landing site deviation and takeoff site deviation can also be called landing longitude deviation and takeoff longitude deviation.

[0113] Then, the first deviation is iterated based on the first variable. Here, the landing time deviation is related to orbital time, while the landing location deviation and takeoff location deviation are related to the orbital plane. Therefore, the first variable is a time- and / or orbital plane-related variable in the first control phase and subsequent control phases of the lunar sampling mission. For example, orbital plane-related variables may include orbital inclination and yaw angle, and time-related variables may include the semi-major axis. Specifically, the first deviation can be iterated based on the first variable using a differential correction algorithm, or it can be iterated based on a sequential quadratic programming algorithm. No specific limitation is made to the algorithm used for iteration here. The sequential quadratic programming algorithm has lower computational efficiency than the differential correction algorithm; therefore, the differential correction algorithm is used as an example in this invention.

[0114] For example, iterative processing based on the differential correction algorithm includes: using the first variable as a constraint variable and the first deviation as a control variable.

[0115] Suppose the constraint variable is an m-dimensional vector Q, and the control variable is an n-dimensional vector P. There is a functional relationship between them, as shown in the following equation: Q = f(P) (1)

[0116] If the initial value of the control variable is P0 and the corresponding value of the constraint variable is Q0, then performing a Taylor expansion of equation (1) at P0 and taking the first-order term, we obtain the following equation:

[0117] In the formula, M is the Jacobian matrix, which reflects the sensitivity of the constraint variable to small changes in the control variable.

[0118] Given the current constraint variable Q0 and the target constraint variable Q s There is a certain deviation Q S If -Q0, then using equation (2), the corrected Q can be calculated iteratively. S The required improvement in the control variable ΔP for Q0 is as follows:

[0119] ΔP=M -1 ΔQ (3)

[0120] If m ≠ n, then ΔP can be calculated using the least norm generalized inverse, as shown in the following equation: ΔP = M T (M·M T ) -1 ·ΔQ(4)

[0121] This process is repeated iteratively until the target constraint variables converge.

[0122] Step 830: When the first deviation is less than the convergence threshold, the target variable of the first control stage is determined so that the satellite can achieve timed and fixed-point landing and timed takeoff based on the target variables of each control stage.

[0123] In this embodiment of the invention, a differential correction algorithm is used to iterate the first deviation based on a first variable. Finally, when the first deviation is less than the convergence threshold, the target variable for the first control stage is determined. The convergence threshold can be a value set empirically, such as 1 second for landing time deviation and 0.001 degrees for landing location deviation and takeoff location deviation. No specific limitation is made to the convergence threshold here.

[0124] Once the above process is completed in each control phase, the target variables for each control phase are obtained, and the timing of landing and takeoff can be achieved based on the target variables of each control phase.

[0125] In this embodiment of the invention, the control phase of the lunar sampling mission includes: mid-course correction, first lunar braking, second lunar braking, third lunar braking, first lunar orbit descent, second lunar orbit descent, orbital reentry combination phasing, powered descent, and lunar surface takeoff. Therefore, the above process needs to be executed multiple times to obtain the target variables for each control phase. Specifically:

[0126] For the mid-course correction control phase of the lunar sampling mission, the orbital root count and insertion time of the current orbit, as well as the nominal parameters for scheduled landing and takeoff in the lunar sampling mission, are determined. For example, taking the retrograde orbit southern hemisphere sampling return as an example, the probe's insertion time is 03 May 2024 10:04:26.870UTCG, the orbital root count is shown in Table 2; the nominal landing time is 01 Jun 2024 22:09:03UTCG; the nominal takeoff time is 03 Jun 2024 23:44:10UTCG; and the landing point's latitude and longitude are (154.47°W, 41.6°S).

[0127] Table 2 Number of six tracks entering the track.

[0128]

[0129] Then, based on the nominal parameters, the number of orbital elements and the insertion time of the orbit in the mid-course correction control phase, the mid-course correction control phase is jointly planned with the first lunar braking, second lunar braking, third lunar braking, first lunar orbit descent, second lunar orbit descent, orbit reentry combination phasing, powered descent, and lunar surface takeoff control phases of the lunar sampling mission, resulting in descent time deviation, descent longitude deviation, and takeoff longitude deviation. Based on the differential correction algorithm, the descent time deviation, descent longitude deviation, and takeoff longitude deviation are iteratively calculated according to the orbital inclination after mid-course correction, the yaw angle of the three lunar brakings, and the semi-major axis of the target orbit after the third lunar braking. This process continues until the descent time deviation, descent longitude deviation, and takeoff longitude deviation are less than the convergence threshold, thus determining the target variables for the mid-course correction control phase.

[0130] For example, planning begins with the first mid-course correction. The mid-course correction is then jointly planned with the first lunar braking, second lunar braking, third lunar braking, first lunar orbit descent, second lunar orbit descent, orbit reentry combination phasing, powered descent, and lunar surface takeoff control phases. The initial values ​​of the planning variables are set as nominal parameters. The nominal parameters correspond to a landing time deviation of 101s, a landing longitude deviation of 3.543°, and a takeoff time longitude deviation of 4.537°. Iteration is performed based on a differential correction algorithm until the landing time deviation, landing longitude deviation, and takeoff longitude deviation are less than the convergence threshold. The iteration process is shown in Table 3. Finally, the mid-course correction targeting lunar inclination angle is determined to be 146.830°, the yaw angle of the three lunar braking maneuvers is -0.966°, and the semi-major axis of the lunar orbit targeted by the third lunar braking maneuver is 1938.360km. The target variable for the mid-course correction control phase is determined to be the lunar inclination angle of 146.830°.

[0131] Table 3. Calculation process for mid-course correction, fixed-point landing, and fixed-takeoff timing.

[0132] Number of iterations <![CDATA[i p_1 / °]]> <![CDATA[Ψ LOI-123 / °]]> <![CDATA[a T-3 / °]]> <![CDATA[ΔT d / s]]> <![CDATA[Δλ d / °]]> <![CDATA[Δλ l / °]]> 1 146.827 -1.072 1938.231 100.698 3.543 4.537 2 146.833 -1.072 1938.231 102.622 4.804 5.678 3 146.827 -1.066 1938.231 100.354 3.335 4.266 4 146.827 -1.072 1938.241 93.241 3.516 4.530 5 146.830 -0.965 1938.359 0.323 0.040 0.027 6 146.830 -0.966 1938.360 -0.004 -0.001 -0.001

[0133] Then, for the first lunar braking control phase of the lunar sampling mission, the number of orbital elements and the orbit insertion time of the current orbit are determined, as well as the nominal parameters for timed landing and takeoff in the lunar sampling mission. For example, continuing from the previous example, the orbit after the first mid-course correction control is taken, and a control error of 0.05 m / s is applied to determine the number of orbital elements of the current orbit.

[0134] Based on nominal parameters, the number of orbital elements and insertion time of the orbit during the first lunar braking control phase, the first lunar braking control phase is jointly planned with the second lunar braking, third lunar braking, first lunar orbit descent, second lunar orbit descent, orbit reentry combination phasing, powered descent, and lunar surface takeoff control phases of the lunar sampling mission, resulting in landing time deviation, landing longitude deviation, and takeoff longitude deviation. Then, based on a differential correction algorithm, the landing time deviation, landing longitude deviation, and takeoff longitude deviation are iteratively calculated according to the yaw angle of the first lunar braking, the yaw angles of the second and third lunar braking, and the semi-major axis of the target orbit after the third lunar braking. This process continues until the landing time deviation, landing longitude deviation, and takeoff longitude deviation are less than the convergence threshold, thus determining the target variables for the first lunar braking control phase.

[0135] For example, starting with the first lunar braking phase, the planning is jointly performed with the second, third, first, and second lunar orbit descent phases, the orbital reentry phase adjustment, powered descent, and lunar surface takeoff control phases. The initial values ​​of the planning variables are set as nominal parameters. Iteration is performed based on a differential correction algorithm until the landing time deviation, landing longitude deviation, and takeoff longitude deviation are less than the convergence threshold. The iteration process is shown in Table 4. The final results show that the yaw angle for the first lunar braking phase is -0.89°, the yaw angles for the second and third lunar braking phases are -1.020°, and the semi-major axis of the lunar orbit targeted by the third lunar braking phase is 1938.356 km. The target variable for the first lunar braking control phase is determined to be a yaw angle of -0.89°.

[0136] Table 4. Calculation process for the first lunar braking, timing, landing, and takeoff.

[0137] Number of iterations <![CDATA[Ψ LOI-1 / °]]> <![CDATA[a T-3 / °]]> <![CDATA[Ψ LOI-23 / °]]> <![CDATA[ΔT d / s]]> <![CDATA[Δλ d / °]]> <![CDATA[Δλ l / °]]> 1 -0.966 1938.361 1.000 -56.873 -2.112 -2.991 2 -0.960 1938.361 1.000 -56.951 -2.116 -2.997 3 -0.966 1938.371 1.000 -64.338 -2.114 -2.992 4 -0.966 1938.361 1.007 -57.014 -2.119 -3.002 5 -3.380 1938.352 0.532 1.900 0.083 0.081 6 -2.221 1938.354 -0.189 1.014 0.041 0.040 7 -0.890 1938.356 -1.020 0.030 0.001 0.001

[0138] Then, for the second lunar braking control phase of the lunar sampling mission, the number of orbital elements and the orbit insertion time of the current orbit are determined, as well as the nominal parameters for timed landing and takeoff in the lunar sampling mission. For example, continuing from the previous example, the orbit after the first lunar braking control is taken, and a control error of 1.5 m / s is applied to determine the number of orbital elements of the current orbit.

[0139] Based on the nominal parameters, the number of orbital elements and the insertion time of the orbit in the second lunar braking control phase, the second lunar braking control phase is jointly planned with the third lunar braking, first lunar orbit descent, second lunar orbit descent, orbit reentry combination phasing, powered descent, and lunar surface takeoff control phases of the lunar sampling mission, resulting in landing time deviation, landing longitude deviation, and takeoff longitude deviation. Then, based on a differential correction algorithm, the landing time deviation, landing longitude deviation, and takeoff longitude deviation are iteratively calculated according to the yaw angle of the second lunar braking, the yaw angle of the third lunar braking, and the semi-major axis of the target orbit after the third lunar braking. This process continues until the landing time deviation, landing longitude deviation, and takeoff longitude deviation are less than the convergence threshold, thus determining the target variables for the second lunar braking control phase.

[0140] For example, starting with the second lunar braking phase, the planning is jointly performed with the third lunar braking phase, the first lunar orbit descent, the second lunar orbit descent, the orbital reentry phase adjustment, the powered descent, and the lunar surface takeoff control phase. The initial values ​​of the planning variables are set as nominal parameters. Iteration is performed based on a differential correction algorithm until the landing time deviation, landing longitude deviation, and takeoff longitude deviation are less than the convergence threshold. The iteration process is shown in Table 5. Finally, the yaw angle for the second lunar braking phase is 1.147°, the yaw angle for the third lunar braking phase is -0.245°, and the semi-major axis of the lunar orbit targeted by the third lunar braking phase is 1938.484 km. The target variable for the second lunar braking control phase is determined to be a yaw angle of 1.147°.

[0141] Table 5. Calculation process for the second near-lunar braking, timing, landing, and takeoff.

[0142] Number of iterations <![CDATA[Ψ LOI-2 / °]]> <![CDATA[a T-3 / °]]> <![CDATA[Ψ LOI-3 / °]]> <![CDATA[ΔT d / s]]> <![CDATA[Δλ d / °]]> <![CDATA[Δλ l / °]]> 1 0.366 1938.582 0.366 -76.037 0.044 0.000 2 0.372 1938.582 0.366 -76.036 0.041 -0.004 3 0.366 1938.592 0.366 -83.666 0.043 -0.001 4 0.366 1938.582 0.374 -76.051 0.040 -0.007 5 1.147 1938.484 -0.245 -0.005 0.000 0.000

[0143] Then, for the third lunar braking control phase of the lunar sampling mission, determine the number of orbital elements and the orbit insertion time of the current orbit, as well as the nominal parameters for timed landing and takeoff in the lunar sampling mission. For example, continuing from the previous example, take the orbit after the second lunar braking control, apply a control error of 1.5 m / s, and determine the number of orbital elements of the current orbit.

[0144] Based on the nominal parameters, the number of orbital elements and the insertion time of the orbit in the third lunar braking control phase, the third lunar braking control phase is jointly planned with the first lunar orbit descent, second lunar orbit descent, orbit reentry combination phasing, powered descent, and lunar surface takeoff control phases of the lunar sampling mission, resulting in descent time deviation, descent longitude deviation, and takeoff longitude deviation. Then, based on a differential correction algorithm, the descent time deviation, descent longitude deviation, and takeoff longitude deviation are iteratively calculated according to the yaw angle of the third lunar braking, the yaw angles of the two lunar orbit descents, and the semi-major axis of the target orbit after the third lunar braking. This process continues until the descent time deviation, descent longitude deviation, and takeoff longitude deviation are less than the convergence threshold, thus determining the target variables for the third lunar braking control phase.

[0145] For example, planning begins with the third lunar braking phase. The third lunar braking phase is jointly planned with the first lunar orbit descent, the second lunar orbit descent, the orbital reentry phase adjustment, powered descent, and lunar surface takeoff control phases. The initial values ​​of the planning variables are set to nominal parameters. Iteration is performed based on a differential correction algorithm until the landing time deviation, landing longitude deviation, and takeoff longitude deviation are less than the convergence threshold. The iteration process is shown in Table 6. The final results show that the yaw angle for the third lunar braking is -0.95°, the yaw angles for the first and second lunar orbit descents are -0.01°, and the semi-major axis of the lunar orbit targeted by the third lunar braking is 1937.73 km. The target variables for the third lunar braking control phase are determined as follows: yaw angle -0.95° and semi-major axis of the lunar orbit 1937.73 km.

[0146] Table 6. Calculation process for the third near-lunar braking, timing, landing, and takeoff.

[0147] Number of iterations <![CDATA[Ψ LOI-3 / °]]> <![CDATA[a T-3 / °]]> <![CDATA[Ψ DM-12 / °]]> <![CDATA[ΔT d / s]]> <![CDATA[Δλ d / °]]> <![CDATA[Δλ l / °]]> 1 -0.966 1938.361 0.001 -467.288 -0.084 -0.008 2 -0.960 1938.361 0.001 -467.422 -0.088 -0.013 3 -0.966 1938.371 0.001 -474.737 -0.085 -0.008 4 -0.966 1938.361 0.008 -467.298 -0.084 -0.008 5 -0.946 1937.733 -0.014 -0.954 -0.001 0.000

[0148] In one possible implementation, a lunar orbit correction control phase might be reserved after the final lunar braking maneuver to correct for the lunar braking residuals and ensure the landing craft lands on time. Therefore, the lunar orbit correction control phase needs to be jointly planned with subsequent control phases. Specifically, for the lunar orbit correction control phase in the lunar sampling mission, the number of orbital elements and the insertion time of the current orbit, as well as the nominal parameters for timed landing and takeoff in the lunar sampling mission, need to be determined. For example, continuing from the previous example, taking the orbit after the third lunar braking maneuver, applying a control error of 0.2 m / s to implement spacecraft separation, the number of orbital elements in the current orbit is determined.

[0149] Based on the nominal parameters, the orbital root number and insertion time of the lunar correction control phase, the lunar correction control phase is jointly planned with the first lunar descent, second lunar descent, and powered descent control phases of the lunar sampling mission to obtain the descent time deviation and descent longitude deviation. Then, based on the differential correction algorithm, the descent time deviation and descent longitude deviation are iteratively calculated according to the semi-major axis of the target lunar correction orbit and the yaw angles of the two lunar descent orbits. This process continues until the descent time deviation and descent longitude deviation are less than the convergence threshold, thus determining the target variables for the lunar correction control phase.

[0150] For example, planning begins with lunar orbit correction, and the lunar orbit correction is jointly planned with the first lunar orbit descent, the second lunar orbit descent, and the powered descent control phase. The initial values ​​of the planning variables are set to nominal parameters. Iteration is performed based on a differential correction algorithm until the descent time deviation and descent longitude deviation are less than the convergence threshold. The iteration process is shown in Table 7. Finally, the lunar orbit correction aims at a semi-major axis of 1939.85 km, and the yaw angles of the first and second lunar orbit descent are -0.49°. The target variable for the lunar orbit correction control phase is determined to be a semi-major axis of 1939.85 km.

[0151] Table 7. Calculation process for lunar orbital correction timing and location landing.

[0152] Number of iterations <![CDATA[a T-hyxz / °]]> <![CDATA[Ψ DM-12 / °]]> <![CDATA[ΔT d / s]]> <![CDATA[Δλ d / °]]> 1 1939.244 -0.715 9.362 0.051 2 1939.244 -0.708 9.361 0.051 3 1939.254 -0.715 9.208 0.051 4 1939.851 -0.481 -0.073 -0.001 5 1939.846 -0.490 0.002 0.000 6 1939.846 -0.490 0.000 0.000

[0153] Then, regarding the first lunar orbit descent control phase of the lunar sampling mission, during the first descent, the probe has already separated from its four spacecraft, and the orbital plane has been determined. Therefore, it will be impossible to aim for a timed launch during the lunar orbit descent. Furthermore, the powered descent process involves landing at a specified latitude. Therefore, it is only necessary to aim for a precise landing. The number of orbital elements and the insertion time of the current orbit, as well as the nominal parameters for a timed landing and launch during the lunar sampling mission, need to be determined. For example, continuing from the previous example, taking the lunar orbit after correction control, applying a control error of 0.2 m / s, the number of orbital elements of the current orbit is determined.

[0154] Based on the nominal parameters, the number of orbital elements and the insertion time of the first lunar descent control phase, the first lunar descent control phase is jointly planned with the second lunar descent and powered descent control phases of the lunar sampling mission to obtain the descent longitude deviation. Then, based on a differential correction algorithm, the descent longitude deviation is iteratively adjusted according to the yaw angles of the two lunar descent phases. This process continues until the descent longitude deviation is less than the convergence threshold, thus determining the target variable for the first lunar descent control phase.

[0155] For example, starting with the first lunar descent orbit planning, the first lunar descent orbit is jointly planned with the second lunar descent orbit and the powered descent control phase, with the initial values ​​of the planning variables set as nominal parameters. Iteration is performed based on a differential correction algorithm until the landing longitude deviation is less than the convergence threshold. The iteration process is shown in Table 8. Finally, the yaw angle for the first and second lunar descent orbits is found to be -0.263°. The target variable for the first lunar descent orbit control phase is determined to be the yaw angle of -0.263°.

[0156] Table 8. Calculation process for the first lunar orbit descent and targeted landing.

[0157]

[0158] Then, for the second lunar orbit descent control phase of the lunar sampling mission, the number of orbital elements and the orbit insertion time of the current orbit are determined, as well as the nominal parameters for timed landing and takeoff in the lunar sampling mission. For example, continuing from the previous example, the orbit after the first lunar orbit descent control is taken, and a control error of 0.2 m / s is applied to determine the number of orbital elements of the current orbit.

[0159] Based on the nominal parameters, the number of orbital elements and the insertion time of the second lunar descent control phase, the second lunar descent control phase is jointly planned with the powered descent control phase of the lunar sampling mission to obtain the descent longitude deviation. Then, based on a differential correction algorithm, the descent longitude deviation is iteratively adjusted according to the yaw angle of the second lunar descent phase. This process continues until the descent longitude deviation is less than the convergence threshold, at which point the target variable for the second lunar descent control phase is determined.

[0160] For example, planning begins with the second lunar descent phase, which is then jointly planned with the powered descent control phase. The initial values ​​of the planning variables are set to nominal parameters. Iteration is performed using a differential correction algorithm until the landing longitude deviation is less than the convergence threshold. The iteration process is shown in Table 9. The final result is a yaw angle of -0.428° for the second lunar descent phase. The target variable for the second lunar descent control phase is then determined to be a yaw angle of -0.428°.

[0161] Table 9. Calculation process for the second lunar orbit descent and timing / location landing.

[0162]

[0163] Actual flight data shows that although the first and second lunar descent orbits no longer aimed at the timed landing target, the landing time deviation was less than 1 minute under the influence of normal orbit determination error and control error.

[0164] Ultimately, after obtaining the target variables for each control phase, the satellite can achieve scheduled landing and takeoff based on these target variables.

[0165] In this embodiment of the invention, lunar sample return missions are divided into four types based on the lunar orbit type and sampling area distribution: prograde lunar northern hemisphere sampling, prograde lunar southern hemisphere sampling, retrograde lunar northern hemisphere sampling, and retrograde lunar southern hemisphere sampling. Secondly, the stages of the sample return mission and the control types involved are analyzed. Combining the differentiated characteristics of the four types of sample return missions, mathematical models for timed landing and takeoff, and a dynamic real-time planning control method for timed landing and takeoff are established. This achieves dynamic joint planning for each control operation, from the first mid-course correction during the Earth-Moon transfer phase to the final orbit descent before landing, with timed landing and takeoff as the ultimate goal, effectively improving the mission's control reconfiguration capability. Simulation examples verify the correctness and feasibility of the strategy. It can be applied to the design of flight control strategies for subsequent (manned) lunar exploration missions in my country.

[0166] Based on the same technological concept Figure 9 An exemplary schematic diagram of a device for planning lunar sampling, timing, landing, and takeoff is provided in an embodiment of the present invention. This device can execute the process of planning lunar sampling, timing, landing, and takeoff.

[0167] like Figure 9 As shown, the device specifically includes:

[0168] The acquisition module 910 is used to determine the orbital six-point number and orbit insertion time of the orbit in the first control phase of the lunar sampling mission. The orbital six-point number is a parameter required to describe the satellite's motion in Kepler orbit.

[0169] The processing module 920 is used to jointly plan the first control phase and the subsequent control phase in the lunar sampling mission based on the orbital six-point number and the orbit insertion time, to obtain a first deviation, and to iterate the first deviation based on a differential correction algorithm according to a first variable; the first deviation is the deviation between the satellite and the nominal parameters when the satellite lands and takes off on the moon, and the first variable is a time- and / or orbital plane-related variable in the first control phase and the subsequent control phase in the lunar sampling mission;

[0170] When the first deviation is less than the convergence threshold, the target variable for the first control phase is determined so that the satellite can achieve scheduled landing and takeoff based on the target variables for each control phase.

[0171] Optionally, the control phase of the lunar sampling mission includes: mid-course correction, first lunar braking, second lunar braking, third lunar braking, first lunar orbit descent, second lunar orbit descent, orbit-return combination phasing, powered descent, and lunar surface takeoff.

[0172] Optionally, the processing module 920 is specifically used for:

[0173] For the mid-course correction control phase in the lunar sampling mission, based on the nominal parameters, the number of orbital elements and the entry time of the orbit in which the mid-course correction control phase is located, the mid-course correction control phase is jointly planned with the first lunar braking, second lunar braking, third lunar braking, first lunar orbit descent, second lunar orbit descent, orbit return combination phasing, powered descent and lunar surface takeoff control phases in the lunar sampling mission, to obtain the landing time deviation, the landing longitude deviation and the takeoff longitude deviation;

[0174] Based on the differential correction algorithm, the landing time deviation, the landing longitude deviation, and the takeoff longitude deviation are iterated according to the mid-course correction orbit inclination angle, the yaw angle of the three lunar brakings, and the semi-major axis of the target orbit after the third lunar braking.

[0175] Optionally, the processing module 920 is specifically used for:

[0176] For the first lunar braking control phase in the lunar sampling mission, based on the nominal parameters, the number of orbital elements and the entry time of the orbit in the first lunar braking control phase, the first lunar braking control phase is jointly planned with the second lunar braking, third lunar braking, first lunar orbit descent, second lunar orbit descent, orbit return combination phasing, powered descent and lunar surface takeoff control phases in the lunar sampling mission, to obtain the landing time deviation, the landing longitude deviation and the takeoff longitude deviation;

[0177] Based on the differential correction algorithm, the landing time deviation, the landing longitude deviation, and the takeoff longitude deviation are iterated according to the yaw angle of the first lunar braking, the yaw angle of the second and third lunar braking, and the semi-major axis of the target orbit after the third lunar braking.

[0178] Optionally, the processing module 920 is specifically used for:

[0179] For the second lunar braking control phase in the lunar sampling mission, based on the nominal parameters, the number of orbital elements and the entry time of the orbit in which the second lunar braking control phase is located, the second lunar braking control phase is jointly planned with the third lunar braking, the first lunar orbit descent, the second lunar orbit descent, the orbit-return combination phasing, the powered descent and the lunar surface takeoff control phases in the lunar sampling mission, to obtain the landing time deviation, the landing longitude deviation and the takeoff longitude deviation;

[0180] Based on the differential correction algorithm, the landing time deviation, the landing longitude deviation, and the takeoff longitude deviation are iterated according to the yaw angle of the second lunar braking, the yaw angle of the third lunar braking, and the semi-major axis of the target orbit after the third lunar braking.

[0181] Optionally, the processing module 920 is specifically used for:

[0182] For the third lunar braking control phase in the lunar sampling mission, based on the nominal parameters, the number of orbital elements and the entry time of the orbit in which the third lunar braking control phase is located, the third lunar braking control phase is jointly planned with the first lunar orbit descent, the second lunar orbit descent, the orbit-return combination phasing, the powered descent and the lunar surface takeoff control phase in the lunar sampling mission, to obtain the landing time deviation, the landing longitude deviation and the takeoff longitude deviation;

[0183] Based on the differential correction algorithm, the landing time deviation, the landing longitude deviation, and the takeoff longitude deviation are iterated according to the yaw angle of the third lunar braking, the yaw angle of the two lunar orbit descents, and the semi-major axis of the target orbit after the third lunar braking.

[0184] Optionally, the processing module 920 is specifically used for:

[0185] For the first lunar orbit descent control phase in the lunar sampling mission, based on the nominal parameters, the number of orbital elements and the entry time of the orbit in the first lunar orbit descent control phase, the first lunar orbit descent control phase is jointly planned with the second lunar orbit descent and powered descent control phases in the lunar sampling mission to obtain the descent longitude deviation.

[0186] Based on the differential correction algorithm, the descent longitude deviation is iterated according to the yaw angle of the two lunar descent orbits.

[0187] Optionally, the processing module 920 is specifically used for:

[0188] For the second lunar orbit descent control phase in the lunar sampling mission, based on the nominal parameters, the number of orbital elements and the entry time of the orbit in the second lunar orbit descent control phase, the second lunar orbit descent control phase is jointly planned with the powered descent control phase in the lunar sampling mission to obtain the descent longitude deviation.

[0189] Based on the differential correction algorithm, the descent longitude deviation is iterated according to the yaw angle of the second lunar descent orbit.

[0190] Based on the same technical concept, embodiments of the present invention also provide a computer device, including:

[0191] Memory, used to store program instructions;

[0192] The processor is used to call the program instructions stored in the memory and execute the above-mentioned method for scheduled lunar sampling, landing, and takeoff according to the obtained program.

[0193] Based on the same technical concept, embodiments of the present invention also provide a computer-readable storage medium storing computer-executable instructions, which are used to cause a computer to execute the above-described method for planning lunar sampling, timing, landing, and takeoff.

[0194] Based on the same technical concept, this invention also provides a computer program product, characterized in that the computer program product includes an executable program, which is executed by a processor to perform the above-described method for planning lunar sampling, timing, landing, and takeoff.

[0195] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0196] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to this application. It should be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0197] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0198] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0199] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A method for planning lunar sampling, timing, location, landing, and takeoff, characterized in that, include: For the first control phase of the lunar sampling mission, the orbital six-root number and orbit insertion time of the orbit in the first control phase are determined, as well as the nominal parameters for timed landing and timed takeoff in the lunar sampling mission. The orbital six-root number is a parameter required to describe the satellite's movement in Kepler orbit, and the nominal parameters include nominal landing time, nominal landing site, and nominal takeoff time. Based on the nominal parameters, the orbital six-element number, and the orbital insertion time, the first control phase is jointly planned with the subsequent control phases in the lunar sampling mission to obtain a first deviation, and the first deviation is iterated based on a first variable; the first deviation is the deviation between the satellite and the nominal parameters when the satellite lands and takes off on the moon, and the first variable is a time- and / or orbital plane-related variable in the first control phase and the subsequent control phases in the lunar sampling mission. When the first deviation is less than the convergence threshold, the target variable for the first control phase is determined so that the satellite can achieve scheduled landing and takeoff based on the target variables for each control phase.

2. The method as described in claim 1, characterized in that, The control phase of the lunar sampling mission includes: mid-course correction, first lunar braking, second lunar braking, third lunar braking, first lunar orbit descent, second lunar orbit descent, orbital reentry combination phasing, powered descent, and lunar surface takeoff.

3. The method as described in claim 2, characterized in that, Based on the nominal parameters, the number of orbital elements, and the orbital insertion time, the first control phase is jointly planned with the subsequent control phases in the lunar sampling mission to obtain a first deviation. The first deviation is then iterated based on a first variable, including: For the mid-course correction control phase in the lunar sampling mission, based on the nominal parameters, the number of orbital elements and the entry time of the orbit in which the mid-course correction control phase is located, the mid-course correction control phase is jointly planned with the first lunar braking, second lunar braking, third lunar braking, first lunar orbit descent, second lunar orbit descent, orbit return combination phasing, powered descent and lunar surface takeoff control phases in the lunar sampling mission, to obtain the landing time deviation, landing longitude deviation and takeoff longitude deviation; Based on the differential correction algorithm, the landing time deviation, the landing longitude deviation, and the takeoff longitude deviation are iterated according to the mid-course correction orbit inclination angle, the yaw angle of the three lunar brakings, and the semi-major axis of the target orbit after the third lunar braking.

4. The method as described in claim 2, characterized in that, Based on the nominal parameters, the number of orbital elements, and the orbital insertion time, the first control phase is jointly planned with the subsequent control phases in the lunar sampling mission to obtain a first deviation. The first deviation is then iterated based on a first variable, including: For the first lunar braking control phase in the lunar sampling mission, based on the nominal parameters, the number of orbital elements and the entry time of the orbit in which the first lunar braking control phase is located, the first lunar braking control phase is jointly planned with the second lunar braking, third lunar braking, first lunar orbit descent, second lunar orbit descent, orbit return combination phasing, powered descent and lunar surface takeoff control phases in the lunar sampling mission, to obtain the landing time deviation, landing longitude deviation and takeoff longitude deviation; Based on the differential correction algorithm, the landing time deviation, the landing longitude deviation, and the takeoff longitude deviation are iterated according to the yaw angle of the first lunar braking, the yaw angle of the second and third lunar braking, and the semi-major axis of the target orbit after the third lunar braking.

5. The method as described in claim 2, characterized in that, Based on the nominal parameters, the number of orbital elements, and the orbital insertion time, the first control phase is jointly planned with the subsequent control phases in the lunar sampling mission to obtain a first deviation. The first deviation is then iterated based on a first variable, including: For the second lunar braking control phase in the lunar sampling mission, based on the nominal parameters, the number of orbital elements and the entry time of the orbit in which the second lunar braking control phase is located, the second lunar braking control phase is jointly planned with the third lunar braking, the first lunar orbit descent, the second lunar orbit descent, the orbit-return combination phasing, the powered descent and the lunar surface takeoff control phase in the lunar sampling mission, to obtain the landing time deviation, landing longitude deviation and takeoff longitude deviation; Based on the differential correction algorithm, the landing time deviation, the landing longitude deviation, and the takeoff longitude deviation are iterated according to the yaw angle of the second lunar braking, the yaw angle of the third lunar braking, and the semi-major axis of the target orbit after the third lunar braking.

6. The method as described in claim 2, characterized in that, Based on the nominal parameters, the number of orbital elements, and the orbital insertion time, the first control phase is jointly planned with the subsequent control phases in the lunar sampling mission to obtain a first deviation. The first deviation is then iterated based on a first variable, including: For the third lunar braking control phase in the lunar sampling mission, based on the nominal parameters, the number of orbital elements and the entry time of the orbit in which the third lunar braking control phase is located, the third lunar braking control phase is jointly planned with the first lunar orbit descent, the second lunar orbit descent, the orbit-return combination phasing, the powered descent and the lunar surface takeoff control phase in the lunar sampling mission, to obtain the landing time deviation, landing longitude deviation and takeoff longitude deviation; Based on the differential correction algorithm, the landing time deviation, the landing longitude deviation, and the takeoff longitude deviation are iterated according to the yaw angle of the third lunar braking, the yaw angle of the two lunar orbit descents, and the semi-major axis of the target orbit after the third lunar braking.

7. The method as described in claim 2, characterized in that, Based on the nominal parameters, the number of orbital elements, and the orbital insertion time, the first control phase is jointly planned with the subsequent control phases in the lunar sampling mission to obtain a first deviation. The first deviation is then iterated based on a first variable, including: For the first lunar orbit descent control phase in the lunar sampling mission, based on the nominal parameters, the number of orbital elements and the entry time of the orbit in the first lunar orbit descent control phase, the first lunar orbit descent control phase is jointly planned with the second lunar orbit descent and powered descent control phases in the lunar sampling mission to obtain the descent longitude deviation. Based on the differential correction algorithm, the descent longitude deviation is iterated according to the yaw angle of the two lunar descent orbits.

8. The method as described in claim 2, characterized in that, Based on the nominal parameters, the number of orbital elements, and the orbital insertion time, the first control phase is jointly planned with the subsequent control phases in the lunar sampling mission to obtain a first deviation. The first deviation is then iterated based on a first variable, including: For the second lunar orbit descent control phase in the lunar sampling mission, based on the nominal parameters, the number of orbital elements and the entry time of the orbit in the second lunar orbit descent control phase, the second lunar orbit descent control phase is jointly planned with the powered descent control phase in the lunar sampling mission to obtain the descent longitude deviation. Based on the differential correction algorithm, the descent longitude deviation is iterated according to the yaw angle of the second lunar descent orbit.

9. A device for planning lunar sampling, timing, location, landing, and takeoff, characterized in that, include: The acquisition module is used to determine the orbital six-root number and orbit insertion time of the orbit in the first control phase of the lunar sampling mission, as well as the nominal parameters for timed landing and takeoff in the lunar sampling mission. The orbital six-root number is a parameter required to describe the satellite's movement in Kepler orbit, and the nominal parameters include nominal landing time, nominal landing site, and nominal takeoff time. The processing module is used to jointly plan the first control phase and the subsequent control phase in the lunar sampling mission based on the nominal parameters, the number of orbital six elements, and the orbit insertion time, to obtain a first deviation, and to iterate the first deviation based on a first variable; the first deviation is the deviation between the satellite and the nominal parameters when the satellite lands and takes off on the moon, and the first variable is a time- and / or orbital plane-related variable in the first control phase and the subsequent control phase in the lunar sampling mission. When the first deviation is less than the convergence threshold, the target variable for the first control phase is determined so that the satellite can achieve scheduled landing and takeoff based on the target variables for each control phase.

10. A computer device, characterized in that, include: Memory, used to store program instructions; A processor is configured to invoke program instructions stored in the memory and execute the method according to any one of claims 1 to 8.

11. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions for causing a computer to perform the method according to any one of claims 1 to 8.

12. A computer program product, characterized in that, The computer program product includes an executable program that is executed by a processor to implement the method of any one of claims 1 to 8.

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