ZEM / ZEV guidance method for Mars powered descent based on interference observation compensation

Abstract

The present invention provides a ZEM / ZEV guidance method for Mars powered descent based on interference observation compensation. The method comprises the following steps: obtaining the three degrees of freedom of a target probe and determining control acceleration constraints based on the three degrees of freedom; determining a disturbance estimate of the target probe using a sliding mode disturbance observer based on the three degrees of freedom; determining a control acceleration of the target probe using a ZEM / ZEV guidance law based on the disturbance estimate, the three degrees of freedom, and the control acceleration constraints; and determining the thrust provided by the target probe's engine based on the control acceleration using the three degrees of freedom, thereby performing compensation guidance on the target probe. The present invention has the beneficial effect of improving the landing accuracy, stability, and safety of a powered descent on Mars while maintaining near-optimal fuel consumption.

Description

Technical Field

[0001] The present invention relates to the field of Mars powered descent guidance technology, and in particular to a Mars powered descent ZEM / ZEV guidance method, device, electronic equipment and storage medium based on interference observation compensation. Background Art

[0002] The process of a precise soft landing on Mars consists of three key phases: atmospheric entry, parachute descent, and powered descent. During this phase, the probe utilizes reverse thrust engines to effectively decelerate, enabling a safe landing at the target location. This phase is the final, critical stage of a Mars probe's landing, crucial for achieving a successful, precise soft landing.

[0003] When designing the guidance law for the powered descent, it's necessary to control acceleration to achieve a soft landing while minimizing fuel consumption. However, during the powered descent on Mars, factors such as wind and dust on the Martian surface, as well as uncertainty in the probe's own model, may interfere. Without appropriate compensation or adaptive adjustments, landing accuracy is likely to decline.

[0004] Existing Mars powered descent guidance schemes can be categorized into two types: computational guidance and feedback guidance. Traditional computational guidance requires extensive online computation and lacks robustness. While offline trajectory planning and tracking are possible, if the probe deviates significantly from the desired trajectory, it can lead to long-term trigger saturation, resulting in excessive fuel consumption and even the risk of damage. Summary of the Invention

[0005] Aiming to solve at least one of the technical problems existing in the prior art, the present invention provides a Mars powered descent ZEM / ZEV guidance method based on interference observation compensation, which improves the landing accuracy, stability and safety of the Mars powered descent stage while keeping the fuel approximately optimal.

[0006] One aspect of the present invention provides a Mars powered descent ZEM / ZEV guidance method based on interference observation compensation, comprising:

[0007] Acquiring three degrees of freedom of the target detector, and determining control acceleration constraint conditions based on the three degrees of freedom;

[0008] Determining a disturbance estimate of the target detector using a sliding mode disturbance observer based on the three degrees of freedom;

[0009] Determining the control acceleration of the target detector observed by the disturbance using a ZEM / ZEV guidance law based on the disturbance estimate, three degrees of freedom, and control acceleration constraints;

[0010] According to the control acceleration, the thrust provided by the engine of the target probe is determined through the three degrees of freedom, and then compensation guidance is performed on the target probe.

[0011] According to the Mars powered descent ZEM / ZEV guidance method based on interference observation compensation, the three degrees of freedom of the target probe are obtained, and the control acceleration constraint conditions are determined according to the three degrees of freedom, including:

[0012] The dynamic equations of the three degrees of freedom are:

[0013]

[0014] Where r = [r x ,r y ,r z ] T ,v=[v x ,v y ,v z ] T ,a=[a x ,a y ,a z ] T are the position vector, velocity vector, and control acceleration vector provided by thrust, respectively. x, y, z are the spatial coordinates of the landing point of the target probe, and g = [0, 0, g] T is the gravitational acceleration on Mars, d=[d x ,d y ,d z ] T is the interference acceleration vector, the interference acceleration vector represents the interference, m is the mass of the target detector, F=[F x ,F y ,F z ] T is the engine thrust vector, is the thrust value, c p =I sp g e is the engine exhaust velocity, I sp is the specific impulse, g e is the acceleration due to Earth's gravity;

[0015] According to the landing time of the target probe, the control acceleration constraint condition is determined as:

[0016] v(t f )=v f , r(t f )=r f

[0017] Among them, t f For landing time.

[0018] According to the Mars powered descent ZEM / ZEV guidance method based on interference observation compensation, wherein according to the three degrees of freedom, a sliding mode interference observer is used to determine the interference estimation value of the target detector, including:

[0019] The sliding mode disturbance observer is:

[0020]

[0021] where λ≥d imax , d imax is the upper bound of the absolute value of the interference, η∈(0,1), α1 and α2 are positive constants to be determined, T c is the predetermined time for the velocity error to converge, i represents x, y, z, i.e. the landing position of the target detector, is the interference observation vector The component of is the interference estimation vector, and δ is the thickness of the saturation function;

[0022] According to the landing point position, determine the saturation function thickness δ and the predetermined time T for the velocity error to converge. c , α1, α2 and η, and, according to the upper limit of the disturbance acceleration d imax Determine λ, where α1, α2, and η are the sliding mode disturbance observer parameters;

[0023] According to the three-degree-of-freedom velocity vector and the sliding mode disturbance observer, the disturbance observation vector is determined. where the interference observation vector This is the interference estimate.

[0024] According to the Mars powered descent ZEM / ZEV guidance method based on interference observation compensation, the sliding mode interference observer is used to calculate the time T of the Mars powered descent ZEM / ZEV. c Converges to |s i |<δ as a constraint.

[0025] According to the Mars powered descent ZEM / ZEV guidance method based on interference observation compensation, the ZEM / ZEV guidance law is used to determine the control acceleration of the target probe obtained by compensation after interference observation based on the interference estimation value, three degrees of freedom and control acceleration constraints, including:

[0026] The control acceleration of the target detector obtained by compensation is:

[0027]

[0028] Where a is the control acceleration, t go For the remaining time, is the interference observation value, where ZEM is the zero control miss distance, ZEV is the zero control velocity deviation, and ZEV=v f -(v+t go g), where ZEM and ZEV represent the differences between the expected position and expected velocity and the predicted position and predicted velocity of the target detector after the current time when no additional control is applied.

[0029] According to the Mars powered descent ZEM / ZEV guidance method based on interference observation compensation, wherein according to the control acceleration, the thrust provided by the engine of the target probe is determined through the three degrees of freedom, and then the target probe is compensated for and guided, including:

[0030] According to the interference observation value through ZEM / ZEV guidance law The three degrees of freedom are used to compensate for the interference d, and the thrust required to be provided by the transmitter of the target detector at the current time is determined, and the thrust required to be provided is performed according to the thrust required.

[0031] The real-time position and velocity of the target probe are monitored and compensated for until the target probe reaches the spatial coordinates of the landing point.

[0032] According to the Mars powered descent ZEM / ZEV guidance method based on interference observation compensation, the ZEM / ZEV guidance law takes reaching the landing point and soft landing as constraints, where soft landing means that the acceleration is controlled to be 0 during landing, that is, r(t f )=0,v(t f )=0.

[0033] Another aspect of the present invention provides a Mars powered descent ZEM / ZEV guidance device based on interference observation compensation, comprising:

[0034] The first module is used to obtain the three degrees of freedom of the target detector and determine the control acceleration constraint conditions according to the three degrees of freedom;

[0035] A second module is configured to determine an interference estimation value of the target detector using a sliding mode interference observer based on the three degrees of freedom;

[0036] A third module is configured to determine the control acceleration of the target detector observed by the interference using a ZEM / ZEV guidance law based on the interference estimate, three degrees of freedom, and control acceleration constraints;

[0037] The fourth module is used to determine the thrust provided by the engine of the target probe through the three degrees of freedom according to the control acceleration, and then perform compensation guidance on the target probe.

[0038] Another aspect of an embodiment of the present invention provides an electronic device, including a processor and a memory;

[0039] The memory is used to store programs;

[0040] The processor executes the program to implement the method described above.

[0041] Embodiments of the present invention further disclose a computer program product or computer program, which includes computer instructions stored in a computer-readable storage medium. A processor of a computer device can read the computer instructions from the computer-readable storage medium and execute the computer instructions, causing the computer device to perform the method described above.

[0042] The beneficial effects of the present invention are: the ZEM / ZEV guidance law is compensated based on the interference observer, the calculation amount is less than that of the existing technology, the system resource consumption during guidance is reduced, the stability of the compensated system is guaranteed, and the safety of the detector is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is a schematic diagram of the trajectory of the powered descent phase of the Mars probe according to an embodiment of the present invention.

[0044] Figure 2 It is a schematic diagram of the ZEM / ZEV guidance process for Mars powered descent based on interference observation compensation according to an embodiment of the present invention.

[0045] Figure 3 4 is a structural diagram of a detector guidance system with an interference observer according to an embodiment of the present invention.

[0046] Figure 4a , 4b is a diagram of the estimation results of the sliding mode observer under step interference and triangular wave interference in an embodiment of the present invention.

[0047] Figure 5a ,5b is a diagram of simulation results of the classic ZEM / ZEV guidance law of an embodiment of the present invention.

[0048] Figure 6a , 6b, 6c, and 6d are schematic diagrams of simulation of the ZEM / ZEV guidance law based on interference observation compensation according to an embodiment of the present invention.

[0049] Figure 7 Schematic diagram of a Mars powered descent ZEM / ZEV guidance device based on interference observation compensation according to an embodiment of the present invention. DETAILED DESCRIPTION

[0050] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. In the subsequent description, suffixes such as "module," "component," or "unit" used to represent elements are used solely to facilitate the description of the present invention and have no specific meaning in themselves. Therefore, "module," "component," or "unit" may be used interchangeably. "First," "second," and the like are used solely to distinguish technical features and should not be construed as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features. In this subsequent description, the consecutive numbering of method steps is for ease of review and understanding. In conjunction with the overall technical solution of the present invention and the logical relationship between the various steps, adjusting the order of implementation of the steps does not affect the technical effects achieved by the technical solution of the present invention. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and should not be construed as limiting the present invention.

[0051] Please refer to Table 1 for explanation of some parameters of the embodiment of the present invention.

[0052] Table 1 Parameter explanation reference table

[0053]

[0054]

[0055] The variable symbol has a 0 in the lower right corner, indicating the initial value; the variable symbol has an f in the lower right corner, indicating the terminal moment value. f represent the detector positions at the initial and terminal moments, respectively.

[0056] refer to Figure 1 , Figure 1 This figure is a schematic diagram of the Mars rover's powered descent trajectory, according to an embodiment of the present invention. During this stage, the rover uses a controlled acceleration provided by its reverse thrust engine to effectively decelerate, enabling precise control of a soft landing at the desired point. By adjusting the controlled acceleration a, the rover's flight trajectory can be tailored to meet various safety requirements.

[0057] In some embodiments, since the landing process of the probe lasts for a very short time, high accuracy can be achieved even without using a complex gravity field model; and the relative distance between the lander and the surface of Mars does not change much, so the gravitational acceleration can be regarded as a constant, usually -3.711400m / s2.

[0058] refer to Figure 2 ,in Figure 21 is a schematic diagram of a ZEM / ZEV guidance process for Mars powered descent based on interference observation compensation according to an embodiment of the present invention, which includes but is not limited to steps S100 to S400:

[0059] S100 , obtaining the three degrees of freedom of the target detector, and determining control acceleration constraint conditions based on the three degrees of freedom.

[0060] In some embodiments, the probe is considered as a point mass and the rotation of Mars is ignored. The three-degree-of-freedom dynamic equation of the probe is:

[0061]

[0062] Where r = [r x ,r y ,r z ] T ,v=[v x ,v y ,v z ] T ,a=[a x ,a y ,a z ] T are the position vector, velocity vector, and control acceleration vector provided by thrust, respectively. x, y, z are the spatial coordinates of the landing point of the target probe, and g = [0, 0, g] T is the gravitational acceleration on Mars, d=[d x ,d y ,d z ] T is the interference acceleration vector, the interference acceleration vector represents the interference, m is the mass of the target detector, F=[F x ,F y ,F z ] T is the engine thrust vector, is the thrust value, c p =I sp g e is the engine exhaust velocity, I sp is the specific impulse, g e is the acceleration due to Earth's gravity.

[0063] It can be understood that the designed control acceleration needs to satisfy v(t f )=v f , r(t f )=r f , t f For landing time.

[0064] S200, based on the three degrees of freedom, use a sliding mode disturbance observer to determine the interference estimate of the target detector. In some embodiments, the sliding mode disturbance observer is as follows

[0065]

[0066] Where, the subscript i represents x, y, and z (the same notation is used in the following text), The interference observation vector Component, λ≥d imax , d imax is the upper bound of the absolute value of the interference, η∈(0,1), α1 and α2 are positive constants to be determined, T c It is the expected time for the velocity error to converge.

[0067] In some embodiments, the saturation function thickness δ and the predetermined time T for the velocity error to converge are determined according to the landing point position. c , α1, α2 and η, and, according to the upper limit of the disturbance acceleration d imax Determine λ, where α1, α2 and η are the parameters of the sliding mode disturbance observer; determine the disturbance observation vector according to the velocity vector of the three degrees of freedom and the sliding mode disturbance observer where the interference observation vector This is the interference estimate.

[0068] It can be understood that η∈(0,1) in the sliding mode disturbance observer is a parameter for nonlinear adjustment of the speed error, and α1 and α2 are linear gains after nonlinear adjustment of the error. η, α1, and α2 together determine the predetermined time T c .

[0069] If η and T are determined first c , then α1 and α2 can be calculated based on Make a selection

[0070] In some embodiments, the sliding mode disturbance observer design process includes:

[0071] (1) The designed sliding mode disturbance observer can ensure Scheduled time T c Converges to |s i |<δ.

[0072] The designed sliding mode variables are:

[0073]

[0074] Taking the derivative with respect to time we get:

[0075] , when |s|≥δ, select the Lyapunov function:

[0076]

[0077] Taking the derivative with respect to time we get:

[0078]

[0079] Select α1 and α2 so that but

[0080]

[0081] Convert differential inequalities to differential equations:

[0082]

[0083] Calculate the stabilization time:

[0084]

[0085] Visible system scheduled time T c Converges to |s i |<δ.

[0086] (2) When |s i |<δ, When bounded, The index approaches The region represented by in Indicates d i The nth-order time derivative of , which has the same meaning as other parameters.

[0087] Select the following Lyapunov function:

[0088]

[0089] Taking the derivative with respect to time we get:

[0090]

[0091] Pick but:

[0092]

[0093] when Right now hour, visible When bounded, The index approaches The area represented.

[0094] It can be understood that from the above analysis, the designed sliding mode observer can estimate the external interference within a predetermined time, thereby improving the accuracy of interference estimation.

[0095] S300, based on the interference estimation value, three degrees of freedom and control acceleration constraints, the ZEM / ZEV guidance law is used to determine the control acceleration of the interference observed target detector.

[0096] In some embodiments, the control acceleration of the disturbed observed target detector (the control acceleration of the compensated target detector) is determined as:

[0097]

[0098] Where a is the control acceleration, t go For the remaining time, is the interference observation value, where ZEM is the zero control miss distance, ZEV is the zero control velocity deviation, and ZEV=v f -(v+t go g), where ZEM and ZEV represent the differences between the expected position and expected velocity and the predicted position and predicted velocity of the target detector after the current time when no additional control is applied.

[0099] In some embodiments, the performance indicators of the ZEM / ZEV guidance law are as follows:

[0100]

[0101] The three-degree-of-freedom dynamic equations and the following boundary conditions must be met:

[0102] r(t0)=r0,r(t f )=r f ,v(t0)=v0,v(t f )=v f

[0103] Among them, t f is the flight time, r0, v0, r f and v f They are initial position, initial velocity, target position and target velocity respectively. The Hamiltonian function is defined as:

[0104]

[0105] Among them, p r and p v are the co-state vectors related to position and velocity respectively. The final optimal control law is:

[0106]

[0107] ZEM and ZEV represent the difference between the desired final position and velocity and the predicted final position and velocity if no additional control is applied after the current time. The expressions for ZEM and ZEV are as follows:

[0108]

[0109] ZEV=v f -(v+t go g)

[0110] The ZEM / ZEV guidance law is obtained from the expressions of ZEM and ZEV:

[0111]

[0112] Under the ZEM / ZEV guidance law, fuel can be nearly optimal, but the ZEM / ZEV guidance law was not designed to take interference into account. For the ZEM / ZEV guidance law, after being disturbed by external factors, the following are the results:

[0113]

[0114] Therefore, it is necessary to observe the interference and then offset it, and then compensate the ZEM / ZEV guidance law to ensure the stability of the system. First, the compensated ZEM / ZEV guidance law is clarified, and the actual control acceleration is as follows:

[0115]

[0116] analyze:

[0117] (1) First, analyze the effectiveness of the guidance law. Applying the control acceleration shown in the form of control acceleration, the system can eventually reach the target point and achieve a soft landing, that is, r(t f )=0,v(t f )=0.

[0118] For the following function:

[0119]

[0120] Taking the derivative with respect to time we get:

[0121]

[0122] Solve the equation:

[0123]

[0124] get:

[0125]

[0126] Among them, C is a constant determined by the initial value. As time goes by, t go →0, then but Bounded, r i →0, v i →0,r(t f )=0,v(t f )=0.

[0127] (2) Next, the stability of the system is analyzed. The disturbance observation form shown in the sliding mode disturbance observer formula and the control acceleration shown in the actual control acceleration formula are used to control the system stability.

[0128] Proof: Choose the following Lyapunov function:

[0129]

[0130] Taking the derivative with respect to time we get:

[0131]

[0132] It can be seen that the V3 index approaches a neighborhood of V3=0 which becomes smaller with time, so we have

[0133] Solve the equation:

[0134]

[0135] get:

[0136]

[0137] Among them, C2 is a constant determined by the initial value, indicating that r i Bounded and r i →0,v i →0, the system is stable. Based on the above analysis, we can know the effectiveness and robustness of the designed guidance law.

[0138] S400: Determine the thrust provided by the engine of the target probe through three degrees of freedom according to the control acceleration, and then perform compensation guidance on the target probe.

[0139] In some embodiments, reference Figure 3 The structure diagram of the detector guidance system with a disturbance observer is shown in FIG. The position and velocity information of the detector are substituted into the actual control acceleration formula and the disturbance estimation value to obtain the control acceleration. Then, the three-degree-of-freedom dynamic equation is used to obtain the thrust that the engine should provide. After implementing the guidance scheme based on disturbance observation compensation, the following is obtained: Figure 3 The guidance system structure shown.

[0140] In some embodiments, the Martian environment and probe model parameters used in the simulation are shown in Table 2. Because the horizontal and vertical directions do not interfere with each other during guidance, and the vertical direction is related to whether the ground will be impacted, the interference in this embodiment of the present invention is only in the vertical direction as an example. The interference form and parameters are shown in Table 3, and the sliding mode observer parameters are shown in Table 4.

[0141] Table 2 Basic parameters of Mars environment and probe model

[0142] parameter Value unit parameter Value unit g [0；0；-3.711400] <![CDATA[m / s -2 ]]> <![CDATA[r0]]> <![CDATA[[r x0 ;0;1500]]]> m <![CDATA[m0]]> 1905 kg <![CDATA[v0]]> [100；0；-75] m / s <![CDATA[c p ]]> 2000 m / s <![CDATA[r f ]]> [0；0；0] m <![CDATA[t f ]]> 55 s <![CDATA[v f ]]> [0；0；0] m / s

[0143] Table 3 Interference forms and parameters

[0144]

[0145] Table 4 Sliding mode observer parameters

[0146] parameter Value unit η 0.3 - <![CDATA[T c ]]> 0.05 s <![CDATA[α1]]> 150 - <![CDATA[α2]]> 150 - δ 0.0005 m / s λ 2 <![CDATA[m / s 2 ]]>

[0147] In some embodiments, the simulation conditions are as follows:

[0148] (1)r x0 =2000(m), d=d1, verify the estimation performance of sliding mode disturbance observer;

[0149] (2)r x0 =2000(m), d=d2, verify the estimation performance of sliding mode disturbance observer;

[0150] (3)r x0 =-500, 0, 500, 1000, 1500, 2000, d = d3, using the classic ZEM / ZEV guidance law simulation;

[0151] (4)r x0 =-500, 0, 500, 1000, 1500, 2000, d = d3, the proposed ZEM / ZEV guidance law based on interference observation compensation is used for simulation; the termination condition of the simulation is t>t f -0.01s.

[0152] Simulation results: The simulation results corresponding to working condition 1 and working condition 2 are plotted on Figure 4a and Figure 4b , the simulation results corresponding to working condition 3 are plotted on Figure 5a and Figure 5b , Figure 6a , Figure 6b , Figure 6c and Figure 6d This is the simulation result corresponding to working condition 4.

[0153] Figure 4a represents the step disturbance simulation result, Figure 4bRepresents the simulation result of triangle wave interference, Figure 4a and Figure 4b As can be seen, the designed sliding mode disturbance observer can quickly track the upward step signal within 0.01 seconds, demonstrating a relatively fast tracking speed. Furthermore, when tracking the triangular wave signal, it exhibits minimal tracking error. Therefore, the performance of the designed sliding mode observer meets the application requirements. In summary, the sliding mode disturbance observer employed in the embodiments of the present invention is reliable for compensating the ZEM / ZEV guidance law.

[0154] Figure 5a It represents the simulation results before the classic ZEM / ZEV guidance law interference compensation. Figure 5b The simulation diagram of the actual control acceleration change of the z-axis before the interference compensation of the classic ZEM / ZEV guidance law is shown in Figure 5. As can be seen from Figure 5, before the interference compensation is performed, the probe will hit the surface of Mars midway, and the control acceleration will become negative in the later stage, violating the thrust angle constraint;

[0155] Depend on Figure 6a , Figure 6b , Figure 6c and Figure 6d It can be seen that the error of the sliding mode observer is less than 0.003m / s under complex fast-changing interference. 2 If the disturbance observer compensation designed in this embodiment of the present invention is incorporated into the guidance framework, the probe can avoid collision with the Martian surface and maintain normal acceleration.

[0156] The above results indicate that the sliding mode observer designed in the embodiment of the present invention can effectively perform active interference compensation, allowing the probe to fly according to the trajectory designed by ZEM / ZEV, achieving near-optimal fuel efficiency, successfully completing the designated mission, achieving a precise soft landing, and ensuring the safe operation of the probe.

[0157] The embodiments of the present invention innovatively propose a ZEM / ZEV guidance method based on interference observation compensation. This method compensates the ZEM / ZEV guidance law based on the interference observer. The resulting guidance scheme has the advantages of low computational complexity, approximate fuel optimization, practicality and effectiveness, and can ensure the stability of the compensated system, improve the safety of the detector, and expand the practical application effect and value of the ZEM / ZEV guidance law.

[0158] Figure 7 FIG. 7 is a diagram of a ZEM / ZEV guidance and analysis device for Mars powered descent based on interference observation compensation according to an embodiment of the present invention. The device includes a first module 710 , a second module 720 , a third module 730 , and a fourth module 740 .

[0159] Among them, the first module is used to obtain the three degrees of freedom of the target detector and determine the control acceleration constraints based on the three degrees of freedom; the second module is used to determine the interference estimation value of the target detector based on the three degrees of freedom using a sliding mode disturbance observer; the third module is used to determine the control acceleration of the target detector after interference observation using the ZEM / ZEV guidance law based on the interference estimation value, three degrees of freedom and control acceleration constraints; the fourth module is used to determine the thrust provided by the target detector's engine through the three degrees of freedom based on the control acceleration, and then perform compensatory guidance on the target detector.

[0160] For example, with the cooperation of the first module, the second module, the third module, and the fourth module in the device, the embodiment device can implement any of the aforementioned ZEM / ZEV guidance methods for Mars powered descent based on interference observation compensation, namely, obtaining the three degrees of freedom of the target probe, determining the control acceleration constraints based on the three degrees of freedom; using a sliding mode interference observer to determine the interference estimate of the target probe based on the three degrees of freedom; using the ZEM / ZEV guidance law to determine the control acceleration of the interference-observed target probe based on the interference estimate, the three degrees of freedom, and the control acceleration constraints; and determining the thrust provided by the target probe's engine based on the three degrees of freedom, thereby performing compensated guidance on the target probe. The beneficial effects of the present invention are: using the interference observer to compensate the ZEM / ZEV guidance law, the computational complexity is relatively low compared to the prior art, reducing system resource consumption during guidance, ensuring the stability of the compensated system, and improving the safety of the probe.

[0161] An embodiment of the present invention further provides an electronic device, the electronic device including a processor and a memory;

[0162] The memory stores a program;

[0163] The processor executes a program to perform the aforementioned Mars powered descent ZEM / ZEV guidance method based on interference observation compensation; the electronic device has the function of carrying and running the software system for Mars powered descent ZEM / ZEV guidance based on interference observation compensation provided by an embodiment of the present invention, such as a personal computer, a minicomputer, a main frame, a workstation, a network or distributed computing environment, a separate or integrated computer platform, or communicating with a charged particle tool or other imaging device, etc.

[0164] An embodiment of the present invention further provides a computer-readable storage medium storing a program, wherein the program is executed by a processor to implement the Mars powered descent ZEM / ZEV guidance method based on interference observation compensation as described above.

[0165] In some optional embodiments, the function / operation mentioned in the block diagram may not occur in the order mentioned in the operation diagram. For example, depending on the function / operation involved, the two boxes shown in succession can actually be executed substantially simultaneously or the boxes can sometimes be executed in reverse order. In addition, the embodiment presented and described in the flow chart of the present invention is provided in an exemplary manner for the purpose of providing a more comprehensive understanding of the technology. The disclosed method is not limited to the operation and logic flow presented herein. Optional embodiments are contemplated in which the order of the various operations is changed and the sub-operations described as a part of a larger operation are performed independently.

[0166] Embodiments of the present invention also disclose a computer program product or computer program, which includes computer instructions stored in a computer-readable storage medium. A processor of a computer device can read the computer instructions from the computer-readable storage medium and execute the computer instructions, causing the computer device to perform the aforementioned Mars powered descent ZEM / ZEV guidance method based on interference observation compensation.

[0167] Furthermore, although the present invention is described in the context of functional modules, it should be understood that, unless otherwise indicated, one or more of the functions and / or features described may be integrated into a single physical device and / or software module, or one or more functions and / or features may be implemented in separate physical devices or software modules. It will also be understood that a detailed discussion of the actual implementation of each module is not necessary for understanding the present invention. More specifically, given the properties, functions, and internal relationships of the various functional modules in the devices disclosed herein, the actual implementation of the module will be understood within the ordinary skill of an engineer. Therefore, a person skilled in the art using ordinary skill will be able to implement the present invention set forth in the claims without undue experimentation. It will also be understood that the specific concepts disclosed are merely illustrative and are not intended to limit the scope of the present invention, which is determined by the full scope of the appended claims and their equivalents.

[0168] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0169] The logic and / or steps represented in the flowcharts or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing the logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (e.g., a computer-based system, a system including a processor, or other system that can fetch and execute instructions from an instruction execution system, apparatus, or device). For purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport a program for use by, or in conjunction with, an instruction execution system, apparatus, or device.

[0170] More specific examples (a non-exhaustive list) of computer-readable media include the following: an electrical connection with one or more wires (electronic devices), a portable computer disk cartridge (magnetic devices), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), a fiber optic device, and a portable compact disc read-only memory (CDROM). In addition, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, deciphering, or processing in another suitable manner as necessary, and then stored in a computer memory.

[0171] It should be understood that various parts of the present invention can be implemented using hardware, software, firmware, or a combination thereof. In the above-described embodiments, multiple steps or methods can be implemented using software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented using hardware, as in another embodiment, any one of the following technologies known in the art or a combination thereof can be used: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application-specific integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0172] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0173] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the claims and their equivalents.

[0174] The above is a specific description of the preferred implementation of the present invention, but the present invention is not limited to the embodiments. Those skilled in the art can make various equivalent modifications or substitutions without violating the spirit of the present invention. These equivalent modifications or substitutions are all included in the scope defined by the claims of this application.

Claims

1. A Mars powered descent ZEM / ZEV guidance method based on interference observation compensation, characterized in that: include: Acquiring three degrees of freedom of the target detector, and determining control acceleration constraint conditions based on the three degrees of freedom; Determining a disturbance estimate of the target detector using a sliding mode disturbance observer based on the three degrees of freedom; Determining the control acceleration of the target detector observed by the disturbance using a ZEM / ZEV guidance law based on the disturbance estimate, three degrees of freedom, and control acceleration constraints; determining the thrust provided by the engine of the target probe through the three degrees of freedom according to the control acceleration, thereby performing compensation guidance on the target probe; The step of obtaining the three degrees of freedom of the target detector and determining the control acceleration constraint conditions according to the three degrees of freedom includes: The dynamic equations of the three degrees of freedom are: ， in, , , are the position vector, velocity vector and the control acceleration vector provided by the thrust, , , is the spatial coordinate of the landing point of the target detector, is the gravitational acceleration on Mars, is the disturbance acceleration vector, which represents the disturbance. is the target detector quality, is the engine thrust vector, is the thrust value, is the engine exhaust velocity, It is specific impulse, is the acceleration due to Earth's gravity; According to the landing time of the target probe, the control acceleration constraint condition is determined as: ， ， in, For landing time.

2. The Mars powered descent ZEM / ZEV guidance method based on interference observation compensation according to claim 1 is characterized in that: Determining the interference estimation value of the target detector using a sliding mode disturbance observer according to the three degrees of freedom includes: The sliding mode disturbance observer is: ， in , is the upper bound of the absolute value of the interference, , , , and is a positive constant to be determined, , is the expected time for the velocity error to converge, express , , That is, the landing position of the target probe, for Interference Observation Vector The components of , i.e., the interference estimation vector, is the saturation function thickness; according to the landing point position, the saturation function thickness is determined , the expected time for the speed error to converge 、 、 and , and, according to the upper bound of the disturbance acceleration Sure ,in 、 and are the sliding mode disturbance observer parameters; According to the three-degree-of-freedom velocity vector and the sliding mode disturbance observer, the disturbance observation vector is determined. , where the interference observation vector This is the interference estimate.

3. The Mars powered descent ZEM / ZEV guidance method based on interference observation compensation according to claim 2, characterized in that: The sliding mode disturbance observer is Converge to As a constraint.

4. The Mars powered descent ZEM / ZEV guidance method based on interference observation compensation according to claim 2, characterized in that: The method of determining the control acceleration of the target detector by compensating after disturbance observation using a ZEM / ZEV guidance law based on the disturbance estimation value, three degrees of freedom, and control acceleration constraints includes: The control acceleration of the target detector obtained by compensation is: ， in, To control acceleration, For the remaining time, is the interference observation value, where The zero-control miss distance is is the zero control speed deviation, where , , where ZEM and ZEV represent the differences between the desired position and desired velocity and the predicted position and predicted velocity when the target detector no longer applies additional control after the current time.

5. The Mars powered descent ZEM / ZEV guidance method based on interference observation compensation according to claim 4 is characterized in that: The method of determining the thrust provided by the engine of the target probe through the three degrees of freedom according to the control acceleration, and then performing compensation guidance on the target probe, includes: Through the ZEM / ZEV guidance law, according to the interference observation value and the three degrees of freedom to disturbance Compensation is performed to determine the thrust required by the target probe's engine at the current time, the target probe is controlled according to the required thrust, and the real-time position and speed of the target probe are monitored and compensated for until the target probe reaches the spatial coordinates of the landing point.

6. The Mars powered descent ZEM / ZEV guidance method based on interference observation compensation according to claim 4, characterized in that: The ZEM / ZEV guidance law takes reaching the landing point and soft landing as constraints, where soft landing means that the control acceleration is 0 during landing, that is, , .

7. A Mars powered descent ZEM / ZEV guidance device based on interference observation compensation, applied to the Mars powered descent ZEM / ZEV guidance method based on interference observation compensation as claimed in any one of claims 1 to 6, characterized in that: include: The first module is used to obtain the three degrees of freedom of the target detector and determine the control acceleration constraint conditions according to the three degrees of freedom; A second module is configured to determine an interference estimation value of the target detector using a sliding mode interference observer based on the three degrees of freedom; A third module is configured to determine the control acceleration of the target detector observed by the interference using a ZEM / ZEV guidance law based on the interference estimate, three degrees of freedom, and control acceleration constraints; The fourth module is used to determine the thrust provided by the engine of the target probe through the three degrees of freedom according to the control acceleration, and then perform compensation guidance on the target probe.

8. An electronic device, characterized in that: including a processor and a memory; The memory is used to store programs; The processor executes the program to implement the Mars powered descent ZEM / ZEV guidance method based on interference observation compensation as described in any one of claims 1-6.

9. A computer-readable storage medium, characterized in that The storage medium stores a program, and the program is executed by a processor to implement the Mars powered descent ZEM / ZEV guidance method based on interference observation compensation as described in any one of claims 1 to 6.

Images