A method and device for collaborative trajectory tracking control of multiple aerospace vehicles under time-varying communication

Abstract

The present invention discloses a method and device for collaborative trajectory tracking control of multiple aerospace vehicles under time-varying communication. Starting from ensuring the rapidity of system parameter adjustment and the robustness in dealing with interference and uncertainty, the invention integrates classical control and adaptive control theories, and proposes an aircraft trajectory tracking control strategy based on the improved L1 adaptive control method. The invention proposes a complete framework for solving the aircraft trajectory tracking control problem, decouples the problem into two control loops, an inner loop and an outer loop, and generates a highly robust collaborative control strategy. The improved L1 adaptive control method is applied to the stabilization control of the speed control loop to deal with communication limitations, ensure safety, and avoid collisions.

Description

Technical Field

[0001] The present invention relates to an aircraft trajectory tracking method, and more specifically, to a collaborative trajectory tracking control method and device for multiple spacecraft under time-varying communication. Background Art

[0002] Multi-agent systems have great advantages in various tasks and are widely used: ground aircraft cooperative control, aviation formation, underwater robot formation and cluster, etc. The resulting multi-agent cooperative control problem has become a research hotspot. China has successfully established a national space station. The expansion of strategic space has brought new problems, that is, under the conditions of outer space missions, a single aircraft is no longer suitable for some tasks. At this time, a multi-aircraft formation must complete the task. Compared with traditional single aerospace vehicles, formation aerospace vehicles have the advantages of good flexibility, high reliability and low cost. Aerospace vehicle formation technology has a wide range of applications in the fields of spacecraft on-orbit service, deep space exploration, spacecraft tracking and monitoring, etc. Considering the cooperative control of multiple aircraft, it is limited by the service quality of the communication link. If there is a disorder in the information flow between machines, the single machine and the formation cannot be connected or the amount of information is limited, a robust cooperative control strategy needs to be generated between the machines to cope with communication restrictions, ensure safety, and avoid collisions. Summary of the invention

[0003] The present invention is provided to solve the above-mentioned problems existing in the prior art. The present invention is a method and device for collaborative trajectory tracking control of multiple aerospace vehicles under time-varying communication, which can achieve the coordination of the entire fleet by adjusting the speeds between multiple machines under the support of the inter-machine communication network, and uses a distributed robust collaborative control law based on the proportional integral method, and improves the application of the L1 adaptive control method and the stabilization control of the speed control loop to cope with the speed oscillation phenomenon under the time-varying conditions of the communication topology structure, thereby ensuring the stability and consistency of the entire collaborative control closed-loop system.

[0004] The present invention specifically adopts the following technical solutions:

[0005] According to a first solution of the present invention, a method for collaborative trajectory tracking control of multiple spacecraft under time-varying communication is provided, the method comprising:

[0006] Add a linear PID or nonlinear PID to the L1 adaptive control structure to improve the accuracy of command tracking and eliminate the time lag in the tracking process;

[0007] The linear PID is expressed as:

[0008]

[0009] Where u(t) is the input signal, K pis the proportional coefficient, e(t) is the deviation signal, K i is the integration coefficient, K d is the differential coefficient, is the derivative of the deviation signal;

[0010] The nonlinear PID is expressed as:

[0011]

[0012] Where u(t) is the input signal, K p is the proportionality coefficient, K i is the integral coefficient, e0(t), e1(t), and e2(t) are the deviation signals transmitted by the three channels respectively;

[0013] Given a space trajectory that a flying object can fly as the expected space trajectory;

[0014] The flying object is controlled to converge to the desired spatial trajectory under the premise of satisfying specific constraints.

[0015] According to a second solution of the present invention, there is provided a multi-space vehicle collaborative trajectory tracking control device under time-varying communication, the device comprising an L1 adaptive control structure and a trajectory generation module, the L1 adaptive control structure comprising a linear PID or a nonlinear PID;

[0016] The linear PID is expressed as:

[0017]

[0018] Where u(t) is the input signal, K p is the proportional coefficient, e(t) is the deviation signal, K i is the integration coefficient, K d is the differential coefficient, is the derivative of the deviation signal;

[0019] The nonlinear PID is expressed as:

[0020]

[0021] Where u(t) is the input signal, K p is the proportionality coefficient, K i is the integral coefficient, e0(t), e1(t), and e2(t) are the deviation signals transmitted by the three channels respectively;

[0022] The trajectory generation module is configured to give a space trajectory that the flying object can fly as the expected space trajectory;

[0023] The L1 adaptive control structure is configured to control the flying object to converge to the desired spatial trajectory under the premise of satisfying specific constraints.

[0024] According to the method and device for collaborative trajectory tracking control of multiple aerospace vehicles under time-varying communication of each scheme of the present invention, formation collaborative control of multiple space vehicles is proposed for the first time, and an improved method based on L1 adaptive control is proposed for the first time. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In the drawings, which are not necessarily drawn to scale, the same reference numerals may describe similar parts in different views. The same reference numerals with letter suffixes or different letter suffixes may represent different instances of similar parts. The accompanying drawings generally illustrate various embodiments by way of example and not limitation, and together with the specification and claims, are used to illustrate the embodiments of the invention. When appropriate, the same reference numerals are used throughout the drawings to refer to the same or similar parts. Such embodiments are illustrative and are not intended to be exhaustive or exclusive embodiments of the present apparatus or method.

[0026] Figure 1 To improve the closed-loop structure diagram of the L1 adaptive control system.

[0027] Figure 2 It is a nonlinear PID controller structure.

[0028] Figure 3 This is a framework diagram for the collaborative trajectory tracking problem of multiple flying objects.

[0029] Figure 4 This is the structural block diagram of the speed stabilization control loop. DETAILED DESCRIPTION

[0030] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. The embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings and specific embodiments, but are not intended to limit the present invention. For the various steps described herein, if there is no necessity for a causal relationship between each other, the order in which they are described as examples herein should not be regarded as a limitation, and those skilled in the art should know that they can be adjusted in order, as long as the logic between them is not destroyed, resulting in the inability to implement the entire process.

[0031] An embodiment of the present invention provides a method for collaborative trajectory tracking control of multiple space vehicles under time-varying communications. The method first improves the existing L1 adaptive control method. The core idea of ​​L1 adaptive control is to decouple the adaptive loop and the control loop by introducing a low-pass filter in the control loop, so that the system can quickly adapt to uncertain changes in parameters or interference without sacrificing robustness. The present invention improves the accuracy of command tracking and eliminates the time lag phenomenon in the tracking process by adding a nonlinear PID controller to the L1 adaptive control structure. At the same time, the improved L1 method is improved over the original method in terms of transient performance, further enhancing the practicability of the method. Improved L1 adaptive control system closed-loop structure such as Figure 1 shown.

[0032] This embodiment adds a linear / nonlinear PID term to the L1 adaptive control structure to improve the accuracy of instruction tracking and eliminate the time lag phenomenon in the tracking process.

[0033] Linear PID:

[0034]

[0035] Where u(t) is the input signal, K p is the proportional coefficient, e(t) is the deviation signal, K i is the integration coefficient, K d is the differential coefficient, is the derivative of the deviation signal;

[0036] Nonlinear PID:

[0037]

[0038] Where u(t) is the input signal, K p is the proportionality coefficient, K i is the integral coefficient, e0(t), e1(t), and e2(t) are the deviation signals transmitted by the three channels respectively.

[0039] The structure of nonlinear PID controller is as follows: Figure 2 shown.

[0040] Based on the improved L1 adaptive control structure, a trajectory generation algorithm is used to give a flyable spatial trajectory of the flying object as the expected spatial trajectory, and let the flying object converge to the expected spatial trajectory generated in the first part as quickly as possible under the premise of satisfying specific constraints.

[0041] Define the trajectory tracking problem: For a given aircraft, design the pitch rate q(t), yaw rate r(t) and virtual target forward speed under the premise of satisfying the feasible constraints. The feedback control law makes all closed-loop system signals bounded and the trajectory tracks the error vector x pf converges to zero.

[0042] The above description can be understood as an aircraft trajectory tracking control strategy based on the improved L1 adaptive control method. This control strategy defines the aircraft trajectory tracking problem at the kinematic level, clarifies the control goals and objects, and decomposes the aircraft trajectory tracking control problem into inner and outer loops. An outer-loop guidance control law based on the dynamic inverse method and an aircraft inner-loop adaptive stabilization controller based on the improved L1 adaptive control method are designed respectively.

[0043] Define the multi-machine collaborative trajectory tracking problem: Figure 3 and Figure 4 As shown, given n aircraft and the desired space trajectory p d,i (t d ), and the communication between each aircraft is supported by the inter-aircraft communication network. The feedback control laws of the pitch rate q(t), yaw rate r(t) and speed v(t) of all aircraft are designed to satisfy:

[0044] (1) All closed-loop signals are bounded;

[0045] (2) For each aircraft i, j = 1, ..., n, the trajectory tracking error vector converges to zero;

[0046] (3) For any two aircraft i and j, i, j = 1, ..., n, the coordination error l′ i -l′ j and the rate of change of the coordinated state All converge to zero and ensure that the time constraints of the task are met;

[0047] The distributed cooperative control rate is expressed as:

[0048]

[0049] Among them, aircraft n l ≤n is selected as the virtual leader, k p and k I is a positive cooperative control gain, is the cooperative control law, l′ i (t) is the rate of change of the ith cooperative state, l′ j (t) is the rate of change of the jth cooperative state, l fi is the total path length of the i-th aircraft, v d，i is the expected speed of the i-th aircraft, χ I，i (t) is the sum of the distances between the ith aircraft and its adjacent aircraft, is the derivative of the sum of the distances between the i-th aircraft and its adjacent aircraft.

[0050] The above-mentioned multi-aircraft collaborative trajectory tracking control strategy considering the time-varying constraints of the communication topology not only describes the problem as a classic consistency problem in the field of robotics, derives and establishes a problem model of collaborative control, but also designs a distributed robust collaborative control law based on the proportional-integral method. When dealing with the speed oscillation phenomenon caused by the time-varying communication topology, the improved L1 adaptive control method is applied to the stabilization control of the speed control loop to ensure the stability and consistency of the entire collaborative control closed-loop system.

[0051] The embodiment of the present invention further provides a multi-space vehicle collaborative trajectory tracking control device under time-varying communication, characterized in that the device includes an L1 adaptive control structure and a trajectory generation module, the L1 adaptive control structure includes a linear PID or a nonlinear PID;

[0052] The linear PID is expressed as:

[0053]

[0054] Where u(t) is the input signal, K p is the proportional coefficient, e(t) is the deviation signal, K i is the integration coefficient, K d is the differential coefficient, is the derivative of the deviation signal;

[0055] The nonlinear PID is expressed as:

[0056]

[0057] Where u(t) is the input signal, K p is the proportionality coefficient, K i is the integral coefficient, e0(t), e1(t), and e2(t) are the deviation signals transmitted by the three channels respectively.

[0058] The trajectory generation module is configured to give a space trajectory that the flying object can fly as the expected space trajectory;

[0059] The L1 adaptive control structure is configured to control the flying object to converge to the desired spatial trajectory under the premise of satisfying specific constraints.

[0060] In some embodiments, the trajectory generation module is further configured to give a flyable space trajectory of the flying object as the expected space trajectory through a trajectory generation algorithm.

[0061] In some embodiments, the L1 adaptive control structure is further configured to: for a given aircraft, under the premise of satisfying the feasible constraints, design the pitch rate q(t), yaw rate r(t) and virtual target forward rate The feedback control law makes all closed-loop system signals bounded and the trajectory tracks the error vector x pf converges to zero.

[0062] In some embodiments, the L1 adaptive control structure is further configured to:

[0063] Define the multi-machine collaborative trajectory tracking problem: Given n aircraft and the desired spatial trajectory p d,i (t d ), and the communication between each aircraft is supported by the inter-aircraft communication network. The feedback control laws of the pitch rate q(t), yaw rate r(t) and speed v(t) of all aircraft are designed to satisfy:

[0064] (1) All closed-loop signals are bounded;

[0065] (2) For each aircraft i, j = 1, ..., n, the trajectory tracking error vector converges to zero;

[0066] (3) For any two aircraft i and j, i, j = 1, ..., n, the coordination error l′ i -l′ j and the rate of change of the coordinated state All converge to zero and ensure that the time constraints of the task are met;

[0067] The distributed cooperative control rate is expressed as:

[0068]

[0069] Among them, aircraft n l ≤n is selected as the virtual leader, k p and k I is a positive cooperative control gain, is the cooperative control law, l′ i (t) is the rate of change of the ith cooperative state, l′ j (t) is the rate of change of the jth cooperative state, l fi is the total path length of the i-th aircraft, v d，i is the expected speed of the i-th aircraft, χ I，i (t) is the sum of the distances between the ith aircraft and its adjacent aircraft, is the derivative of the sum of the distances between the i-th aircraft and its adjacent aircraft.

[0070] The device described in the embodiment of the present invention and the method described previously belong to the same technical concept and can achieve the same technical effect, which will not be described in detail here.

[0071] In addition, although exemplary embodiments have been described herein, the scope includes any and all embodiments based on the present invention with equivalent elements, modifications, omissions, combinations (e.g., various embodiments intersecting schemes), adaptations or changes. The elements in the claims will be interpreted broadly based on the language adopted in the claims, and are not limited to the examples described in this specification or during the implementation of this application, and the examples will be interpreted as non-exclusive. Therefore, this specification and examples are intended to be considered as examples only, and the true scope and spirit are indicated by the following claims and the full scope of their equivalents.

[0072] The above description is intended to be illustrative rather than restrictive. For example, the above examples (or one or more of them) can be used in combination with each other. For example, those of ordinary skill in the art can use other embodiments when reading the above description. In addition, in the above-mentioned specific embodiments, various features can be grouped together to simplify the present invention. This should not be interpreted as a feature of an invention that is not claimed for protection being necessary for any claim. On the contrary, the subject matter of the present invention may be less than all the features of the embodiments of a specific invention. Thus, the following claims are incorporated into the specific embodiments as examples or embodiments, wherein each claim is independently used as a separate embodiment, and it is considered that these embodiments can be combined with each other in various combinations or arrangements. The scope of the present invention should be determined with reference to the full scope of the equivalent forms of the attached claims and these claims.

Claims

1. A method for collaborative trajectory tracking control of multiple spacecraft under time-varying communication, characterized in that: The method comprises: Add a linear PID or nonlinear PID to the L1 adaptive control structure to improve the accuracy of command tracking and eliminate the time lag in the tracking process; The linear PID is expressed as: Where u(t) is the input signal, K p is the proportional coefficient, e(t) is the deviation signal, K i is the integration coefficient, K d is the differential coefficient, is the derivative of the deviation signal; The nonlinear PID is expressed as: Where u(t) is the input signal, K p is the proportionality coefficient, K i is the integral coefficient, e0(t), e1(t), and e2(t) are the deviation signals transmitted by the three channels respectively; Given a space trajectory that a flying object can fly as the expected space trajectory; Controlling the flying object to converge to the desired spatial trajectory under the premise of satisfying specific constraints; The controlling the flying object to converge to the desired space trajectory under the premise of satisfying specific constraints includes: Given n aircraft and desired space trajectory p d,i (t d ), and the communication between each aircraft is supported by the inter-aircraft communication network. The feedback control laws of the pitch rate q(t), yaw rate r(t) and speed v(t) of all aircraft are designed to satisfy: (1) All closed-loop signals are bounded; (2) For each aircraft i, j = 1, ..., n, the trajectory tracking error vector converges to zero; (3) For any two aircraft i and j, i, j = 1, ..., n, the coordination error l′ i -l′ j and the rate of change of the coordinated state All converge to zero and ensure that the time constraints of the task are met; The distributed cooperative control rate is expressed as: Among them, aircraft n l ≤n is selected as the virtual leader, k p and k I is a positive cooperative control gain, is the cooperative control law, l′ i (t) is the rate of change of the ith cooperative state, l′ j (t) is the rate of change of the jth cooperative state, l fi is the total path length of the i-th aircraft, v d，i is the expected speed of the i-th aircraft, χ I，i (t) is the sum of the distances between the ith aircraft and its adjacent aircraft, is the derivative of the sum of the distances between the i-th aircraft and its adjacent aircraft.

2. The method according to claim 1, characterized in that A space trajectory that the flying object can fly is given as the expected space trajectory through the trajectory generation algorithm.

3. The method according to claim 1, characterized in that The controlling the flying object to converge to the desired space trajectory under the premise of satisfying specific constraints includes: For a given aircraft, under the premise of satisfying the feasible constraints, the feedback control laws of the pitch rate q(t), yaw rate r(t) and virtual target forward rate l(t) are designed so that all closed-loop system signals are bounded and the trajectory tracking error vector x pf converges to zero.

4. A multi-space vehicle collaborative trajectory tracking control device under time-varying communication, characterized in that: The device includes an L1 adaptive control structure and a trajectory generation module, wherein the L1 adaptive control structure includes a linear PID or a nonlinear PID; The linear PID is expressed as: Where u(t) is the input signal, K p is the proportional coefficient, e(t) is the deviation signal, K i is the integration coefficient, K d is the differential coefficient, is the derivative of the deviation signal; The nonlinear PID is expressed as: Where u(t) is the input signal, K p is the proportionality coefficient, K i is the integral coefficient, e0(t), e1(t), and e2(t) are the deviation signals transmitted by the three channels respectively; The trajectory generation module is configured to give a space trajectory that the flying object can fly as the expected space trajectory; The L1 adaptive control structure is configured to control the flying object to converge to the desired spatial trajectory under the premise of satisfying specific constraints; The L1 adaptive control structure is further configured as: Define the multi-machine collaborative trajectory tracking problem: Given n aircraft and the desired spatial trajectory p d,i (t d ), and the communication between each aircraft is supported by the inter-aircraft communication network. The feedback control laws of the pitch rate q(t), yaw rate r(t) and speed v(t) of all aircraft are designed to satisfy: (1) All closed-loop signals are bounded; (2) For each aircraft i, j = 1, ..., n, the trajectory tracking error vector converges to zero; (3) For any two aircraft i and j, i, j = 1, ..., n, the coordination error l′ i -l′ j and the rate of change of the coordinated state All converge to zero and ensure that the time constraints of the task are met; The distributed cooperative control rate is expressed as: Among them, aircraft n l ≤n is selected as the virtual leader, k p and k I is a positive cooperative control gain, is the cooperative control law, l′ i (t) is the rate of change of the ith cooperative state, l′ j (t) is the rate of change of the jth cooperative state, l fi is the total path length of the i-th aircraft, v d，i is the expected speed of the i-th aircraft, χ I，i (t) is the sum of the distances between the ith aircraft and its adjacent aircraft, is the derivative of the sum of the distances between the i-th aircraft and its adjacent aircraft.

5. The device according to claim 4, characterized in that The trajectory generation module is further configured to give a flyable space trajectory of the flying object as the expected space trajectory through a trajectory generation algorithm.

6. The device according to claim 4, characterized in that The L1 adaptive control structure is further configured as: For a given aircraft, under the premise of satisfying the feasible constraints, the pitch rate q(t), yaw rate r(t) and virtual target forward rate are designed. The feedback control law makes all closed-loop system signals bounded and the trajectory tracks the error vector x pf converges to zero.

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