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CN-119512193-B - Distributed SAR satellite specified time attitude cooperative anti-saturation control method

CN119512193BCN 119512193 BCN119512193 BCN 119512193BCN-119512193-B

Abstract

The invention discloses a distributed satellite scheduled time gesture collaborative anti-saturation control method, which comprises the steps of firstly establishing an SAR satellite formation model considering saturation constraint, then designing a preset performance boundary function which can be converged within preset performance boundary, then aiming at the problems of external interference, actuator saturation constraint and the like of a satellite formation flying system, and finally designing an SAR satellite scheduled time gesture collaborative control law based on an anti-saturation compensator, an interference observer and sliding mode control.

Inventors

  • XIAO CHAO
  • GUO YONG
  • WANG LIHAO
  • Mo Xiangyang
  • LI AIJUN
  • WANG CHANGQING

Assignees

  • 西北工业大学

Dates

Publication Date
20260505
Application Date
20241118

Claims (7)

  1. 1. The method for controlling the collaborative anti-saturation of the preset time posture of the distributed SAR satellite is characterized by comprising the following steps of: step 1, building a SAR satellite formation model considering saturation constraint; Step 1-1, adopting a quaternion description formation satellite attitude kinematic equation as follows: (1) (2) Wherein, the And Respectively representing formation satellites A scalar portion and a vector portion of the gesture quaternion, Indicating formation satellites The attitude angular velocity of the body system relative to the inertial system; step 1-2 for arbitrary vectors Defining a cross operator The method comprises the following steps: (3) the satellite attitude dynamics equation is obtained as follows: (4) Wherein, the Indicating formation satellites Is used for the rotation inertia of the bearing, Indicating the control moment of force, Indicating formation satellites External interference received; Step 1-3, setting Indicating formation satellites Is used for the gesture quaternion of the desired gesture, Indicating formation satellites Defining the quaternion of the attitude error between the body coordinate system and the desired coordinate system as The attitude angular velocity error is The following steps are: (5) (6) (7) Wherein, the For formation of satellites The body coordinate system is a posture transfer matrix between the expected coordinate systems, and the following conditions are satisfied: (8) (9) Formation satellite The attitude error kinematic equation of (2) is: (10) Formation satellite The attitude error dynamics equation of (2) is: (11) step 1-4, converting satellite formation attitude error kinematics and dynamics equation into Euler-Lagrange system form, and forming the satellite The attitude error dynamics equation of (2) is expressed as: (12) Wherein: (13) (14) (15) (16) (17) (18) (19) Definition: (20) (21) (22) Defining a satellite formation error quaternion and derivatives thereof as follows: (23) (24) (25) defining external disturbance and control moment suffered by formation as follows: (26) (27) the attitude error dynamics equation for satellite formation is expressed as: (28) Step 1-5 defining formation satellites Formation satellite The relative attitude error and the first derivative between the two are: (29) (30) defining formation satellites in combination with communication topological relations among formation members The attitude cooperative error of (a) and the first derivative thereof are as follows: (31) (32) Wherein, the Weighted connection matrix for representing graph theory In the presence of an element of the group, Degree matrix Elements of (a) and (b); The formulas (31) and (32) are converted into the following formula descriptions: (33) (34) Wherein, the , And (3) with Is a reciprocal matrix; Because the communication topology among the formation satellites is an undirected communication graph, according to graph theory knowledge Is positive and invertible, thus , Equivalent to , Therefore, the controller is designed such that , The attitude tracking control of the formation satellite can be satisfied; step 1-6 assume control inputs in a satellite formation attitude system There is a saturation constraint, and the range of torque that can be provided is: wherein For maximum value of control input, then constrained control input Defined as the form of the saturation function: (35) Since the saturation function shown in the formula (35) is not negligible, the saturation function is smoothed by using the hyperbolic tangent function, and the control input saturation function is redefined as: (36) Obtainable according to formula (16): (37) Then at constrained input The satellite error dynamics equation under action is rewritten as: (38) It is rewritten as: (39) Wherein, the ; Defining a dead zone nonlinear function: (40) When (when) When the controller enters a saturation region, there is Substituting the result into the model (39) to obtain: (41) Adding an anti-saturation compensator to the error model (41) Compensating, and finally obtaining a SAR satellite formation model considering saturation constraint, wherein the model comprises the following steps: (42); Step 2, designing a preset performance boundary function which can be converged in a specified time; boundary function for preset performance control of specified time convergence The following should be satisfied: (57) Wherein, the And The initial and final values of the performance boundary function, Boundary function for user-defined settling time Given by the following first derivative form: (58) Wherein, the , Is a constant and satisfies ; And 3, designing a SAR satellite preset time posture cooperative control law based on the anti-saturation compensator, the interference observer and the sliding mode control.
  2. 2. The method for controlling the cooperative anti-saturation of a predetermined time profile of a distributed SAR satellite according to claim 1, wherein the step 2 specifically comprises: Step 2-1 when In the time-course of which the first and second contact surfaces, Designing the controller such that The method meets the attitude tracking control of the formation satellites and aims at the formation satellites For errors Design preset performance constraints to Represented as Then The requirements are as follows: (43) Wherein, the For a preset performance boundary function to be designed, For overshooting the limiting parameter, when When the overshoot is not allowed to occur; as can be seen from equation (43), for errors To simplify the design of the control law, the inequality constraint is converted into an equality constraint, and the normalized error is defined as: (44) Step 2-2, constructing a mapping function which is smooth and strictly monotonically increasing Error is then The method meets the following conditions: (45) Wherein, the Is a conversion error; It can be seen that: (46) Conversion error The method can be obtained by inverse solution: (47) and normalize the error The method meets the following conditions: (48) the derivation of formula (47) can be obtained: (49) (50) Wherein the method comprises the steps of (51) (52) (53) (54) (55) (56) Step 2-3 boundary function for preset performance control of convergence of specified time The following should be satisfied: (57) Wherein, the And The initial and final values of the performance boundary function, Boundary function for user-defined settling time Given by the following first derivative form: (58) Wherein, the , Is a constant and satisfies 。
  3. 3. The method for controlling the cooperative anti-saturation of the predetermined time profile of the distributed SAR satellite according to claim 2, wherein the step 3 specifically comprises: Step 3-1 for SAR satellite formation model form (42) considering saturation constraint, designing an interference observer of the following form: (59) (60) Wherein, the , In order to assist in the amount of system state, As an estimate of the upper bound of the generalized interference, 、 Are all larger than 0 and are not smaller than 0, In the form of a small quantity of the material, Estimating an error for the interference; Step 3-2, designing a sliding die surface as follows: (61) Wherein, the Is a normal number that satisfies the Hurwitz condition; The derivative of the available slip plane is: (62) Step 3-3 according to And (3) with The reciprocal relationship of (2) can be found: (63) designing formation satellite according to designed slip form surface The control law of (2) is: (64) Wherein, the , For a small amount, the error model compensation term is: (65)。
  4. 4. An electronic device comprising a processor and a memory, the memory for storing a computer program, the processor for executing the computer program stored by the memory to cause the electronic device to perform the method of any one of claims 1 to 3.
  5. 5. A computer readable storage medium, on which a computer program is stored, which computer program, when being executed by a processor, implements the method according to any of claims 1 to 3.
  6. 6. A chip comprising a processor for calling and running a computer program from a memory, causing a device on which the chip is mounted to perform the method of any one of claims 1 to 3.
  7. 7. A computer program product comprising a computer storage medium storing a computer program comprising instructions executable by at least one processor, the instructions when executed by the at least one processor implementing the method of any one of claims 1 to 3.

Description

Distributed SAR satellite specified time attitude cooperative anti-saturation control method Technical Field The invention belongs to the technical field of spacecraft control, and particularly relates to a distributed SAR satellite specified time posture collaborative anti-saturation control method. Background In earth observation, SAR satellite formation synthesizes images by transmitting electromagnetic waves and receiving reflected waves, so that the SAR satellite formation is not limited by illumination and climatic conditions, can take high-resolution microwave photos all the time and all the weather, can even acquire covered information through shallow earth surfaces or sparse vegetation, has irreplaceable uniqueness in the fields of disaster assessment, mineral exploration, military reconnaissance and the like, and is a hot spot for research in the current aerospace application field. As the number of earth-observing tasks increases, SAR satellite convoys are often required to observe multiple target points on the earth in one orbital period. For each target point, it can only be observed by the satellite in its visible time window, so how to trade off and arrange the observation tasks in a limited time window is important to improve the efficiency of the observation tasks. Satellite agility is also a mainstream development direction of the current SAR satellite technology, and by means of a large-moment attitude control mechanism, the remote sensing satellite platform has the performances of rapid large-range attitude maneuver, multiple imaging modes and the like. The formation and agility of the SAR satellites increase the flexibility of the observation task, meanwhile, the problem of planning the observation task is more complex, and the research on the efficient task planning technology is helpful for fully utilizing the maneuvering capability of the agile satellites and improving the observation benefits of the formation of the SAR satellites. When the satellite formation observes a ground target point, the visible time window constraint of the target point needs to be met. According to the result of observation task planning, the gesture transfer time between two adjacent observation targets is limited, and how to complete gesture transfer between targets within the limited time and complete observation of the target point for a specified duration is a key factor for smoothly completing the observation task planning result. Therefore, the problem of cooperative control of the SAR satellite formation attitude at the high-precision appointed time is studied, and the observation performance of formation can be effectively improved. Meanwhile, various interferences exist in the space environment, and in consideration of the saturation phenomenon of the satellite attitude actuator, the research on the cooperative control of the satellite formation attitude under the consideration of external disturbance and the saturation constraint of the actuator is necessary. Disclosure of Invention In order to overcome the defects of the prior art, the invention provides a distributed SAR (SYNTHETIC APERTURE RADAR ) satellite preset time posture collaborative anti-saturation control method, which comprises the steps of firstly establishing an SAR satellite formation model considering saturation constraint, then designing a preset performance boundary function which can be converged in a preset time, then aiming at the problems of external interference, actuator saturation constraint and the like of a satellite formation flying system, and finally designing an SAR satellite preset time posture collaborative control law based on an anti-saturation compensator, an interference observer and sliding mode control. The technical scheme adopted for solving the technical problems is as follows: step 1, building a SAR satellite formation model considering saturation constraint; Step 2, designing a preset performance boundary function which can be converged in a specified time; and 3, designing a SAR satellite preset time posture cooperative control law based on the anti-saturation compensator, the interference observer and the sliding mode control. Preferably, the step 1 specifically includes: Step 1-1, adopting a quaternion description formation satellite attitude kinematic equation as follows: Wherein q 0,i and q v,i represent scalar and vector parts, respectively, of a quaternary of the attitude of the formation satellite i, and ω i represents the angular velocity of the attitude of the formation satellite i body system relative to the inertial system; step 1-2 for arbitrary vectors The cross operator ζ × is defined as: the satellite attitude dynamics equation is obtained as follows: wherein J i represents the moment of inertia of the formation satellite i, u i∈R3 represents the control moment, and d i∈R3 represents the external disturbance experienced by the formation satellite i; Step 1-3, setting Representing expec