Suspension type follow-up system trajectory planning method and system

Abstract

The invention provides a suspension type follow-up system trajectory planning method and system, and relates to the technical field of suspension type micro-low gravity simulation, and the method comprises the steps: constructing a suspension type follow-up system nonlinear prediction model; based on the nonlinear prediction model of the suspension servo system, determining a safe servo trajectory planning target of nonlinear prediction; a model prediction control algorithm is adopted to predict the future motion state of the spacecraft in real time based on the safe follow-up trajectory planning target, the follow-up trajectory of the suspension system is optimized, multiple safety constraint conditions are introduced into the optimization problem, and a follow-up trajectory optimization model is constructed; and based on the follow-up trajectory optimization model, solving an optimal trolley acceleration sequence capable of ensuring the safety of the system, designing a preset time tracking controller by utilizing state transformation, actively setting the convergence time of the system, and enabling the trolley of the suspension follow-up system to track the planned safe follow-up speed trajectory within specified time.

Description

Technical Field

[0001] The present disclosure relates to the technical field of suspended micro-low gravity simulation, and in particular to a trajectory planning method and system for a suspended follower system. Background Art

[0002] The statements in this section merely provide background information related to the present disclosure and do not necessarily constitute prior art.

[0003] Micro-low-gravity simulation is a key technology in ground-based spacecraft testing, primarily used to simulate the micro-low-gravity environment a spacecraft experiences in space or on extraterrestrial bodies. A suspension system can gravity-unload a spacecraft—that is, by applying a force opposite to gravity, partially or completely offsetting the spacecraft's own weight, thereby simulating its motion in a micro-low-gravity field on the ground. In addition to the suspension method, common gravity-unloading methods include air flotation and water flotation. Compared to other gravity-unloading methods, the suspension method is widely used due to its simple structure and wide applicability. A suspended micro-low-gravity simulation system typically consists of a suspension device, a servo control system, and a measurement and feedback system. The suspension device applies a constant suspension force to the spacecraft via suspension ropes to offset (partially) the force of gravity. The servo control system is responsible for adjusting the suspension device's position and attitude in real time to adapt to the spacecraft's motion. The measurement and feedback system uses sensors to collect spacecraft position and attitude information, providing data support for servo control.

[0004] For micro-low-gravity simulation technology, gravity unloading is the core and servo control is the key. Gravity unloading technology provides the basic conditions for simulating micro-low-gravity environments. However, relying solely on gravity unloading technology cannot meet the dynamic motion requirements of spacecraft in ground tests, especially in multi-degree-of-freedom motion scenarios, where the position of the spacecraft changes complexly and rapidly. Therefore, servo control technology has become the key to achieving high-precision micro-low-gravity simulation. Its goal is to accurately follow the motion trajectory of the spacecraft by adjusting the position of the suspension device in real time. The performance of servo control technology directly determines the overall effect of the micro-low-gravity simulation system and is the focus and difficulty of current research.

[0005] Existing follow-up control technologies include proportional-integral-derivative (PID) control methods, PID control variants (such as fuzzy PID), and sliding mode control methods. However, these methods face the following challenges in practical applications:

[0006] 1) The suspended servo system has significant nonlinear characteristics. Traditional linear control methods are difficult to accurately describe the dynamic behavior of the system, resulting in insufficient control accuracy.

[0007] PID control and its variants have limited adaptability to complex dynamic systems. Their performance degrades significantly when system parameters fluctuate significantly or when unknown disturbances occur. While sliding mode control offers some robustness to disturbances, it is prone to chattering, which not only affects system stability but can also cause premature wear of actuators.

[0008] 3) Most existing tracking methods adopt a "passive following" strategy, which lacks the ability to predict the future state of the system, resulting in a significant lag in following the spacecraft motion.

[0009] 4) Traditional methods are designed directly from the control perspective, and there are few trajectory planning methods developed for suspended servo systems. Summary of the Invention

[0010] In order to solve the above problems, the present disclosure proposes a trajectory planning method and system for a suspended servo system, introduces a nonlinear dynamic model with the spacecraft's own driving force, describes the dynamic characteristics of the suspension system under the servo condition, and adopts a model predictive control algorithm to realize the real-time prediction of the future motion state of the spacecraft and the optimization of the servo trajectory of the suspension system; by comprehensively considering multiple safety constraints and using a preset time tracking controller designed by state transformation to break through the limitations of traditional asymptotic convergence, the user can actively set the system convergence time, which is particularly suitable for scenarios where spacecraft suddenly move.

[0011] According to some embodiments, the present disclosure adopts the following technical solutions:

[0012] A trajectory planning method for a suspended servo system, comprising:

[0013] Construct a dynamic model of the suspension servo system with spacecraft driving force, and construct a nonlinear prediction model of the suspension servo system based on the servo target of the dynamic model;

[0014] Based on the nonlinear prediction model of the suspension servo system, the safe servo trajectory planning target of the nonlinear prediction is determined;

[0015] Based on the goal of safe servo trajectory planning, a model predictive control algorithm is used to predict the future motion state of the spacecraft in real time and optimize the servo trajectory of the suspension system. Multiple safety constraints are introduced into the optimization problem to construct a servo trajectory optimization model.

[0016] Based on the servo trajectory optimization model, the optimal trolley acceleration sequence is solved; and the preset time tracking controller is designed by using state transformation to actively set the system convergence time. Within the specified time, the trolley of the suspension servo system will track the planned safe servo trajectory.

[0017] According to some embodiments, the present disclosure adopts the following technical solutions:

[0018] A trajectory planning system for a suspended servo system, comprising:

[0019] The dynamic model construction module is used to construct a dynamic model of the suspension servo system with spacecraft driving force, and to build a nonlinear prediction model of the suspension servo system according to the servo target of the dynamic model of the suspension servo system;

[0020] A target construction module is used to determine the nonlinear prediction safety tracking trajectory planning target based on the nonlinear prediction model of the suspension tracking system;

[0021] The optimization model construction module is used to use the model predictive control algorithm to predict the future motion state of the spacecraft in real time based on the safe follow-up trajectory planning goal, and to optimize the follow-up trajectory of the suspension system. Multiple safety constraints are introduced into the optimization problem to build a follow-up trajectory optimization model;

[0022] The following control module is used to solve the optimal trolley acceleration sequence based on the following trajectory optimization model; and uses state transformation to design a preset time tracking controller, actively setting the system convergence time, so that the trolley of the suspension following system will track the planned safe following trajectory within the specified time.

[0023] According to some embodiments, the present disclosure adopts the following technical solutions:

[0024] A computer program product includes a computer program, and when the computer program is executed by a processor, the method for trajectory planning of a suspended servo system is implemented.

[0025] According to some embodiments, the present disclosure adopts the following technical solutions:

[0026] A non-transitory computer-readable storage medium is used to store computer instructions. When the computer instructions are executed by a processor, a trajectory planning method for a suspended servo system is implemented.

[0027] According to some embodiments, the present disclosure adopts the following technical solutions:

[0028] An electronic device includes: a processor, a memory, and a computer program; wherein the processor is connected to the memory, and the computer program is stored in the memory. When the electronic device is running, the processor executes the computer program stored in the memory to enable the electronic device to implement the trajectory planning method of a suspended follower system.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] The present invention discloses a method for trajectory planning of a suspension servo system. According to the servo target of the suspension servo system dynamics model, a nonlinear prediction model of the suspension servo system is constructed. By introducing a nonlinear prediction model with the spacecraft's own driving force, the system can more accurately describe the dynamic characteristics of the suspension system under servo conditions, thus solving the problem of insufficient servo accuracy in traditional linear model-based methods and significantly improving the trajectory planning performance.

[0031] The present invention discloses a method for trajectory planning of a suspended servo system. Based on the goal of safe servo trajectory planning, the method adopts a model predictive control algorithm to achieve real-time prediction of the future motion state of the spacecraft and optimization of the servo trajectory of the suspension system. This method not only greatly improves the dynamic response speed of the system, but also overcomes the lag defect of the traditional "passive following" method, bringing the real-time and accuracy of servo control to a new level.

[0032] The disclosed method for trajectory planning of a suspended servo system comprehensively considers multiple safety constraints, including key physical quantities such as the suspension system's motion acceleration, the rope deflection angle, and its angular velocity. This ensures that the system effectively avoids safety hazards such as overshoot and oscillation while ensuring high-precision servoing, significantly improving the reliability and stability of the overall operation.

[0033] This paper presents a trajectory planning method for a suspended servo system. By utilizing a preset time tracking controller designed with state transformation, it overcomes the limitations of traditional asymptotic convergence. Users can actively set the system's convergence time (e.g., tracking the planned trajectory within 200ms), making it particularly suitable for scenarios involving sudden spacecraft motion. By combining trajectory planning based on nonlinear dynamic prediction with preset time tracking, this method represents a groundbreaking solution in the field of micro-low gravity simulation, providing more efficient technical support for ground-based testing and verification of spacecraft. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The accompanying drawings, which constitute a part of the present disclosure, are used to provide a further understanding of the present disclosure. The exemplary embodiments of the present disclosure and their descriptions are used to explain the present disclosure and do not constitute an improper limitation to the present disclosure.

[0035] Figure 1 This is a framework diagram of a trajectory planning method for a suspended servo system according to an embodiment of the present disclosure;

[0036] Figure 2 It shows the state, control input, constraint range, and driving force curve of the suspended servo system of the embodiment of the present disclosure, as well as the comparison curve between the servo trajectory of the suspension point and the autonomous motion trajectory of the spacecraft, and the servo error curve.

[0037] in, Figure 2 (a) is the trajectory curve of the trolley and spacecraft. Figure 2(b) is the trolley speed curve. Figure 2 (c) is the trolley following error curve. Figure 2 (d) in the figure is the optimal trolley acceleration and its constraint curve. Figure 2 (e) in the equation is the deflection angle of the suspension rope and its constraint curve. Figure 2 (f) is the angular velocity of the rope deflection and its constraint curve, Figure 2 (g) in the figure is the driving force curve of the spacecraft itself. Figure 2 (h) in FIG. 5 is the control input curve of the preset time tracking controller. DETAILED DESCRIPTION

[0038] The present disclosure will be further described below with reference to the accompanying drawings and embodiments.

[0039] It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of the present disclosure. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present disclosure belongs.

[0040] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present disclosure. As used herein, unless the context clearly indicates otherwise, the singular form is intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0041] Example 1

[0042] In one embodiment of the present disclosure, a method for trajectory planning of a suspended follow-up system is provided. Based on the dynamic model of the suspended follow-up system, a nonlinear state prediction model is established that takes into account the driving force of the spacecraft itself; then, a model predictive control algorithm is used to realize the real-time prediction of the future motion state of the spacecraft and the optimization of the follow-up trajectory of the suspension system; secondly, by comprehensively considering a variety of safety constraints, including the motion acceleration of the suspension system, the deflection angle of the suspension rope and its angular velocity and other key physical quantities, it is ensured that the system effectively avoids safety hazards such as overshoot and oscillation while ensuring high-precision follow-up, and significantly improves the reliability and stability of the overall operation. Finally, the preset time tracking controller designed by state transformation can break through the limitations of traditional asymptotic convergence, and the user can actively set the system convergence time (such as tracking the planned trajectory within 200ms), which is particularly suitable for sudden motion scenarios of spacecraft. The specific steps include:

[0043] Step 1: Construct a dynamic model of the suspension servo system with spacecraft driving force, and construct a nonlinear prediction model of the suspension servo system according to the servo target of the dynamic model of the suspension servo system;

[0044] Step 2: Based on the nonlinear prediction model of the suspension servo system, determine the nonlinear prediction safety servo trajectory planning target;

[0045] Step 3: Based on the safe servo trajectory planning objective, a model predictive control algorithm is used to predict the future motion state of the spacecraft in real time and optimize the servo trajectory of the suspension system. Multiple safety constraints are introduced into the optimization problem to construct a servo trajectory optimization model.

[0046] Step 4: Based on the servo trajectory optimization model, solve the optimal trolley acceleration sequence that can ensure system safety, and use state transformation to design a preset time tracking controller, actively set the system convergence time, so that the trolley of the suspension servo system will track the planned safe servo trajectory within the specified time.

[0047] As an embodiment, the present disclosure provides a trajectory planning method for a suspended follower system, which can dynamically follow the motion of a suspended spacecraft. The specific implementation process is as follows:

[0048] Step 1: Construct a nonlinear prediction model of the suspension servo system considering the spacecraft's own driving force, including: using the Euler-Lagrange equation to construct a dynamic model of the suspension servo system with the spacecraft driving force, setting the servo target of the suspension servo system dynamic model to make the motion trajectory of the trolley follow the motion trajectory of the spacecraft in real time, and constructing a nonlinear prediction model of the suspension servo system according to the servo target of the suspension servo system dynamic model.

[0049] Specifically, using the Euler-Lagrange equation, the following dynamic model of the suspension follower system with spacecraft driving force can be constructed:

[0050]

[0051] Where M is the mass of the trolley, m is the mass of the spacecraft, L is the length of the suspension rope, and g is the acceleration due to gravity. M, m, L, and g are all constants. The variables include the trolley displacement x(t), the suspension rope deflection θ(t), and the spacecraft driving force F(t) and the trolley driving force u(t). is the acceleration of the trolley, is the angular acceleration of the rope deflection. Different from the suspension system in the conventional lifting mode (i.e. the hoisted load has no self-driving force), the dynamic model of the suspension follower system specifically considers the component forces / torques of the spacecraft driving force F(t) on the trolley subsystem and the rope deflection subsystem, which are Fsin 2 θ and FLcosθ.

[0052] The servoing goal of the system is to make the motion trajectory x(t) of the trolley follow the motion trajectory x(t) of the spacecraft in real time. p (t), that is, x(t) = x p (t), where x p =x+Lsinθ. In fact, from x(t) and x p It is not difficult to see that the control target is equivalent to θ(t) = 0. That is, the rope deflection angle is always kept at zero. However, due to the coupling between the trolley and the rope deflection angle, and the spacecraft's own driving force, it is very easy to make θ(t) ≠ 0. Therefore, in order to ensure the follow-up control effect, θ(t) should be kept as close to zero as possible. In this case, x(t) ≈ x p (t).

[0053] In practical applications, most existing motors typically operate in speed mode, meaning they track a given speed signal. To adapt to this operating mode, this disclosure focuses on designing a trajectory planning method for a suspended servo system, enabling the trolley to track the planned trajectory to achieve the desired servo objective. To this end, based on the trajectory planning objective, this disclosure focuses on the following rope deflection dynamics:

[0054]

[0055] Next, define The required nonlinear prediction model can be constructed as:

[0056]

[0057] The nonlinear prediction model (3) will be used as the prediction model for trajectory planning in the future, where and s(t) can be regarded as the input and output of the prediction model respectively, f(·) represents a function vector, and t represents time. In this disclosure, the trajectory planning goal of the servo system is to solve a reasonable After integrating it, the available trolley speed reference signal can be obtained It can be used for dynamic following of autonomous moving spacecraft.

[0058] Step 2: Safe servo trajectory planning based on nonlinear dynamic prediction, including: determining the safe servo trajectory planning target based on the nonlinear prediction model of the suspension servo system; based on the safe servo trajectory planning target, using the model predictive control algorithm to make real-time predictions of the future motion state of the spacecraft, and optimizing the servo trajectory of the suspension system, introducing multiple safety constraints into the optimization problem, and constructing a servo trajectory optimization model.

[0059] Specifically, based on the above-considered goal of trajectory planning for the servo system, the following performance optimization function can be reasonably constructed in the example disclosed herein:

[0060]

[0061] The performance optimization function J is composed of the system state s(t) and the independent variable to be optimized X t Composition, of which T p represents the prediction time, dτ represents the differential element, τ represents the integral variable, Q1 and Q2 are weighted matrices, s r is the expected value of state s, s(τ) represents the value of s at time τ, s r (τ) represents the time τ s r value.

[0062] Obviously, corresponding to the analysis of the trajectory planning goal of the above servo system, there is naturally s r = 0. In addition, the independent variable X t Specifically, it can be written as:

[0063]

[0064] in, is the predicted input sequence, and for any τ∈[t,t+T p ] is defined as:

[0065]

[0066] Among them, T p represents the prediction time domain, int(·) represents the floor function, δ represents the sampling time and satisfies T p =N p δ.

[0067] Therefore, the following optimization problem can be constructed to plan a feasible trolley acceleration trajectory:

[0068]

[0069] Solving this optimization problem can obtain the optimal trolley acceleration sequence X t * , at this time only take X t * The optimal trolley speed reference trajectory can be obtained by integrating the first element in This cycle repeats, using the trajectory It can achieve real-time tracking of autonomously moving spacecraft. It is worth noting that the disclosed example uses a nonlinear prediction model to complete the tracking trajectory planning task, avoiding the approximate error caused by model linearization, and taking into account the spacecraft driving force, improving the robustness of trajectory planning.

[0070] However, the optimal reference trajectory of the trolley planned above can achieve the tracking target, but it does not take into account the transient performance of the suspended servo system. Therefore, considering the transient performance of the suspended servo system, some safety constraints are added to the optimization problem (7). The safety constraints are as follows:

[0071] (1) Trolley motion acceleration constraint:

[0072]

[0073] (2) Rope deflection constraint:

[0074] θ min ≤θ(t)≤θ max

[0075] (3) Rope deflection angular velocity constraint:

[0076]

[0077] Among them, a min and a max They represent the upper and lower bounds of the trolley acceleration, θ min and θ max They represent the upper and lower bounds of the rope deflection angle, β min and β max The upper and lower bounds of the angular velocity of the suspension rope are respectively represented. The introduction of these constraints can greatly improve the safety and servo performance of the suspended servo system. In this way, a new optimization problem (servo trajectory optimization model) can be constructed as follows:

[0078]

[0079] It can be seen from formula (8) that due to the introduction of the rope deflection constraint, when the constraint is set small enough, the following performance can be better guaranteed because θ(t) is small enough, even if x(t) is close enough to x p (t).

[0080] Step 3: Design a preset time tracking controller. Based on the servo trajectory optimization model, solve the optimal trolley acceleration sequence that can ensure system safety, and use state transformation to design a preset time tracking controller. Actively set the system convergence time so that the trolley of the suspension servo system will track the planned safe servo trajectory within the specified time.

[0081] Specifically, in order to quickly track the planned trajectory, a preset time tracking controller is designed for the suspension follower system, which can make the system converge to the above-planned safe follower trajectory within the time specified by the user (such as 200ms). Specifically, the dynamic model (1) of the suspension follower system is used to eliminate the acceleration of the rope deflection angle. You can get:

[0082]

[0083] Since this disclosure focuses on the speed working mode of the servo motor, the speed variable is defined as So we can write the following relationship:

[0084]

[0085] in, and They are the control input gain term and the nonlinear dynamic term. In order to achieve preset time tracking, the state transformation is used Build a new system where y v is the transformed system speed state, is a state change function, and T is the tracking time specified by the user. Next, find y v The first-order derivatives of are:

[0086]

[0087] The predefined time trackers designed are as follows:

[0088]

[0089] Where k is the controller gain to be selected, Obviously, after substituting the controller (12) into the new system (11), the following relationship holds:

[0090]

[0091] This means that v Asymptotically converges, which also means that y v is also bounded. Combined again As can be seen from the relationship, when time t approaches the user-set time T, μ will tend to infinity, but from the above analysis, we can know that y v is bounded, so That is, at the time T specified by the user, the trolley of the suspension servo system will track the planned safe servo speed trajectory.

[0092] Simulation experiment

[0093] The simulation parameters in this disclosure example are selected as follows:

[0094]

[0095] Figure 2 The simulation results of the disclosed example are shown, including the state of the suspended servo system, control input, constraint range, the spacecraft's own driving force curve, the comparison curve between the servo trajectory of the suspension point and the autonomous motion trajectory of the spacecraft, and the servo error curve. Figure 2 It can be seen from the figure that the proposed trajectory planning method for the suspension servo system based on nonlinear dynamic prediction can achieve good servo effect, such as Figure 2 As shown in (a); the tracking error e is as follows Figure 2 As shown in (c), it is within ±2mm. In addition, various safety constraints in the planning process are also met. For example, the rope deflection angle θ(t) is very close to zero and is constrained in the range of [-0.1deg, 0.1deg]. This range effectively ensures the tracking accuracy of the follow-up.

[0096] Angular velocity It is constrained in the range of [-0.5deg / s, 0.5deg / s], and the planned trolley motion acceleration is also constrained in the range of [-0.2m / s 2 ,0.2m / s 2 ] within the preset range, and the planned acceleration is smooth. In addition, Figure 2 (g) and Figure 2 (h) shows the change curves of the spacecraft's own driving force F(t) and the trolley's driving force u(t), respectively. The change trends of the two are very similar, which indirectly illustrates the good performance of the method proposed in this invention.

[0097] In summary, the disclosed method can achieve good tracking effect and effectively utilize the suspension system to achieve real-time tracking of the autonomous motion trajectory of the suspended spacecraft.

[0098] Example 2

[0099] In one embodiment of the present disclosure, a trajectory planning system for a suspended follower system is provided, comprising:

[0100] The dynamic model construction module is used to construct a dynamic model of the suspension servo system with spacecraft driving force, and to build a nonlinear prediction model of the suspension servo system according to the servo target of the dynamic model of the suspension servo system;

[0101] A target construction module is used to determine the nonlinear prediction safety tracking trajectory planning target based on the nonlinear prediction model of the suspension tracking system;

[0102] The optimization model construction module is used to use the model predictive control algorithm to predict the future motion state of the spacecraft in real time based on the safe follow-up trajectory planning goal, and to optimize the follow-up trajectory of the suspension system. Multiple safety constraints are introduced into the optimization problem to build a follow-up trajectory optimization model;

[0103] The following control module is used to solve the optimal trolley acceleration sequence based on the following trajectory optimization model, and use state transformation to design a preset time tracking controller, actively set the system convergence time, and within the specified time, make the trolley of the suspension following system track the planned safe following trajectory.

[0104] Example 3

[0105] In one embodiment of the present disclosure, a computer program product is provided, including a computer program. When the computer program is executed by a processor, the method for trajectory planning of a suspended servo system is implemented.

[0106] Example 4

[0107] In one embodiment of the present disclosure, a non-transitory computer-readable storage medium is provided, wherein the non-transitory computer-readable storage medium is used to store computer instructions. When the computer instructions are executed by a processor, the method for trajectory planning of a suspended servo system is implemented.

[0108] Example 5

[0109] In one embodiment of the present disclosure, an electronic device is provided, comprising: a processor, a memory, and a computer program; wherein the processor is connected to the memory, and the computer program is stored in the memory. When the electronic device is running, the processor executes the computer program stored in the memory, so that the electronic device executes the method for trajectory planning of a suspended servo system.

[0110] The present disclosure is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present disclosure. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0111] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 The steps for the function specified in one or more boxes.

[0112] Although the above describes the specific implementation methods of the present disclosure in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present disclosure. Those skilled in the art should understand that on the basis of the technical solution of the present disclosure, various modifications or variations that can be made by those skilled in the art without creative work are still within the scope of protection of the present disclosure.

Claims

1. A trajectory planning method for a suspended servo system, characterized in that: include: Construct a dynamic model of the suspension servo system with spacecraft driving force, and construct a nonlinear prediction model of the suspension servo system based on the servo target of the dynamic model; Based on the nonlinear prediction model of the suspension servo system, the safe servo trajectory planning target of the nonlinear prediction is determined; Based on the goal of safe servo trajectory planning, a model predictive control algorithm is used to predict the future motion state of the spacecraft in real time and optimize the servo trajectory of the suspension system. Multiple safety constraints are introduced into the optimization problem to construct a servo trajectory optimization model. Based on the servo trajectory optimization model, the optimal trolley acceleration sequence is solved, and the preset time tracking controller is designed by using state transformation. The system convergence time is actively set, so that the trolley of the suspension servo system will track the planned safe servo trajectory within the specified time.

2. A trajectory planning method for a suspended servo system according to claim 1, characterized in that: The Euler-Lagrange equation is used to construct a dynamic model of a suspension servo system with a spacecraft driving force. The servo target of the dynamic model of the suspension servo system is to make the motion trajectory of the trolley follow the motion trajectory of the spacecraft in real time. According to the servo target of the dynamic model of the suspension servo system, a nonlinear prediction model of the suspension servo system is constructed.

3. The trajectory planning method of a suspension-type servo system according to claim 1, characterized in that: The nonlinear prediction model of the suspension servo system is the prediction model for servo trajectory planning. The input and output of the prediction model are determined. The trajectory planning goal of the servo system is to solve the optimal input of the prediction model. After integrating the input of the prediction model, a usable trolley speed reference signal is obtained for dynamic following of the autonomous moving spacecraft.

4. The trajectory planning method of a suspended servo system according to claim 1, wherein: Based on the goal of safe servo trajectory planning, a performance optimization function is constructed. The performance optimization function consists of the system state and the independent variables to be optimized. The model predictive control algorithm is used to make real-time predictions of the future motion state of the spacecraft and optimize the servo trajectory of the suspension system. A servo trajectory optimization model is constructed to plan a feasible trolley acceleration trajectory.

5. The trajectory planning method of a suspended servo system according to claim 1, characterized in that: The optimization problem is solved to obtain the optimal trolley acceleration sequence. Considering the transient performance of the suspended follow-up system, safety constraints are added to the follow-up trajectory optimization model. The safety constraints include trolley motion acceleration constraints, rope deflection constraints, and rope deflection angular velocity constraints.

6. The trajectory planning method of a suspended servo system according to claim 1, characterized in that: Based on the following trajectory optimization model, a preset time tracking controller is designed using state transformation. In order to achieve preset time tracking, a new system is constructed using state transformation, which can enable the system to converge to the planned safe following trajectory at the time specified by the user.

7. A trajectory planning system for a suspended servo system, characterized in that: include: The dynamic model construction module is used to construct a dynamic model of the suspension servo system with spacecraft driving force, and to build a nonlinear prediction model of the suspension servo system according to the servo target of the dynamic model of the suspension servo system; A target construction module is used to determine the nonlinear prediction safety tracking trajectory planning target based on the nonlinear prediction model of the suspension tracking system; The optimization model construction module is used to use the model predictive control algorithm to predict the future motion state of the spacecraft in real time based on the safe follow-up trajectory planning goal, and to optimize the follow-up trajectory of the suspension system. Multiple safety constraints are introduced into the optimization problem to build a follow-up trajectory optimization model; The following control module is used to solve the optimal trolley acceleration sequence based on the following trajectory optimization model, and use state transformation to design a preset time tracking controller, actively set the system convergence time, and within the specified time, make the trolley of the suspension following system track the planned safe following trajectory.

8. A computer program product comprising a computer program, characterized in that When the computer program is executed by a processor, the trajectory planning method of a suspended servo system according to any one of claims 1 to 6 is implemented.

9. A non-transitory computer-readable storage medium, characterized in that The non-transitory computer-readable storage medium is used to store computer instructions. When the computer instructions are executed by the processor, a trajectory planning method for a suspended servo system according to any one of claims 1 to 6 is implemented.

10. An electronic device, characterized in that: include: A processor, a memory, and a computer program; wherein the processor is connected to the memory, the computer program is stored in the memory, and when the electronic device is running, the processor executes the computer program stored in the memory to enable the electronic device to implement a trajectory planning method for a suspended follower system as described in any one of claims 1 to 6.

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