The requirements of the flexibility of aerospace control system are extensively analyzed in this paper,and the challenges are deeply discussed,which are concentrated on the system level and the device level. The design concept of the flexibility of the system level and the device level is proposed in innovation,and the key technical path of the flexibility of the system level and the device level is further elaborated,such as rapid assembly and interoperability management of system software and hardware,multi-level communication interconnection,flexible integrated conformal layout and analysis,and verification of the adaptability of flexible electronics to the aerospace environment,and the development trend of the flexibility of the aerospace control system is finally visioned in terms of integrating innovative technologies,strengthening cross domain cooperation,establishing standards and specifications,and expanding and deepening applications.
Regarding the significant impact of code generation techniques based on large language models (LLMs) on software productivity and their broad application prospects to the aerospace field,the latest research progress on this kind of technology is reviewed from three aspects: problem background and definition,typical technologies and their potential application scenarios in the aerospace domain,and application evaluation methods,with the aim of providing guidance and insights for related research on code generation techniques in the aerospace domain. Firstly,the basic capabilities of LLMs are discussed on code generation according to the features of code generation problem definition and LLMs structures. Then,the main methods for code generation are elaborated,including pre-training,instruction fine-tuning,prompt engineering and retrieval-augmented generation as well as their potential application scenarios to the aerospace field. Next,due to the perspectives of semantic similarity and validation datasets,the popular methods are reviewed for evaluating the results of LLM-based code generation techniques and their characteristics and limitations are analyzed. Finally,the challenges are presented and future improvements are proposed.
A predictive control method for electromagnetic switching valve is proposed for attitude control of spacecraft. Based on the predicted control time and nozzle layout,the ignition logic of electromagnetic valve is designed and the force of the nozzle is utilized to cancel out each other,so that the control torque action time can be adjusted arbitrarily during the control cycle. The simulation analysis shows that compared with conventional pulse width modulation techniques,the predictive control method allows the solenoid valve to achieve precise attitude control without being limited to the minimum continuous opening time.
A design method for an active disturbance rejection controller based on complementary sliding mode is proposed to address the position and attitude control problem during the point cloud data collection process of quadrotor unmanned aerial vehicle (UAV) that carries a light detection and ranging (LiDAR) for power transmission lines. Regarding the problems of strong coupling,non-linearity,and external disturbance effects under the complex environment of quadrotor UAV,a finite time convergent extended state observer is adopted to estimate the state and lumped disturbances of the quadrotor UAV dynamic system,which introduces the observed lumped disturbances into the active disturbance rejection controller for feedforward compensation. At the same time,complementary sliding mode manifolds are established,and the exponential power function and the integral form of sign function are used to ensure the continuity of the active disturbance rejection controller. Finally,a rigorous proof of the asymptotic convergence of position and attitude tracking errors is provided,which is based on the Lyapunov analysis method,and the simulation results show that the proposed method has higher control precision and can effectively suppress different forms of external time-varying disturbances.
The transfer strategies for multi-objective missions around the Earth-Moon Lagrange points are studied and a two-impulse transfer strategy that allows spacecraft to move between near-rectilinear halo orbits and distant retrograde orbits is designed. Firstly,the spacecraft's orbital dynamics model is established in the synodic frame. Then,the overall design of the transfer strategy is implemented,the relevant optimization variables are analyzed,the objective function and constraints are determined,and the transfer strategy design problem is transfered into a trajectory optimization problem. Furthermore,the feasibility of genetic algorithms and particle swarm optimization algorithms for this specific problem is verified for solving the transfer trajectory. A numerical method is presented through this research by applying genetic and particle swarm optimization algorithms to transfer strategies design of halo orbits,which focuses on recent interest in near-rectilinear halo orbits and distant retrograde orbits. The proposed optimization method has ability of effectively resolving the orbital transfer design problem without prior information and can be applied to various transfer scenarios.
Regarding the ascent trajectory of horizontal take-off and landing reusable launch vehicles,a simplex-pseudospectral loop optimization algorithm is proposed. By optimizing the control parameters of the horizontal run section,the initial value of the ascent section is adaptively generated,and taking a certain horizontal take-off and landing reusable launch vehicle as an example,the trajectory optimization design simulation of the launch vehicle from taking off to climbing to the handover point is completed by using the simplex-pseudospectral double-loop optimization algorithm,which verifies the feasibility and effectiveness of the proposed method. On this basis,the influences of engine thrust and sensitive parameters of the flight trajectory on air-breathing mode flight profile and remaining mass are studied. At the same time,a design method of air-breathing mode power compensation is proposed. By comparing with the conventional design method,fuel consumption is further reduced and the carrying capacity of the reusable launch vehicle is improved.
According to the position and attitude control problem of quadrotor unmanned aerial vehicle (UAV) with external disturbances and time-varying loads,a parameter adaptive sliding mode control method is proposed,which is based on the parameter adaptive method and sliding mode control theory.The external disturbances and time-varying loads of quadrotor UAV are estimated and compensated by using parameter adaptive method so that the quadrotor UAV can be enabled to resist the disturbances caused by changes in time-varying loads and the capability of high-precision position and attitude control can be achieved. In the end,the Lyapunov stability theory and simulation results fully verify that the proposed method can effectively degrade the adverse effects of unknown disturbances and time-varying loads on the control system.
A guidance law with variable control weight is proposed,which is based on the optimal control method for intercept different types of maneuvering targets by using air-defense missile. A state equation of relative motion between missile and target in the longitudinal plane is set up,and an indicator function based on variable control weight and line of sight angular velocity constraint is designed,furthermore,the optimal guidance law related to weight coefficients is derived by using the minimum numerical principle. Simulation experiments are implemented for different types of maneuvering targets,and the results indicate that the performance of the optimal guidance approach proposed in this paper is superior to traditional proportional guidance method. The line-of-sight angular velocity convergence is fairly quick,which can form preferable reverse orbit situation. Furthermore,regarding targets under different maneuvering modes,the weight of the optimal guidance law can be adjusted to match the optimal control parameters of each maneuvering target.
Aiming at the orbit determination of non-cooperative continuous low-thrust maneuvering spacecraft,a rapid pre-identification method of thrust acceleration based on single-arc orbit determination is proposed. Based on the relationship between satellite orbit parameters and acceleration,the single-arc orbit determination results of two radar observations with a certain time interval are used to inversely solve the tangential acceleration of the spacecraft under continuous tangential thrust,and fairly smaller solution error is remaining under the condition of sparse data in a short time by using this method Which is applied respectively to the orbital climb of Starlink,OneWeb and the Qianfan constellation. The results show that when the observation interval is greater than 11 h and 15 h separately,the proposed method can realize the rapid pre-identification of the tangential thrust acceleration of Starlink and OneWeb satellites,and the solving error is less than 2%. The calculation results can be used as initial values for precise orbit determination of continuous low-thrust maneuvering spacecraft.
The algorithm of the integrated celestial navigation combined accelerometers with X-ray pulsar sensor is researched. Firstly,the inertial navigation algorithm is provided for spacecraft based on the heliocentric inertial reference frame,and the accelerometer drift is estimated by the phase difference of the inertial navigation and X-ray pulsar sensor in pulsar direction based on PI filter. Then,the algorithm of the integrated celestial navigation combined X-ray pulsar sensor with accelerometers based on the time of arrival (TOA) of the pulsar pulse is proved. Lastly,simulation results show that the algorithm of the integrated celestial navigation is effective.
Based on the upper wind benchmark of the sounding balloon,the upper winds and the precision of corresponding maximum aerodynamic load from the wind profile radar and numerical weather prediction model forecasts from 1st day to 4th day are compared and analyzed. The results show that: the precision of the upper wind from low to high is presented by the wind profile radar and the forecast of the 4th day to the forecast of the 1st day. The precision of the wind profile radar at the altitude of 7.6 km and above is obviously low,and absolute difference is more than 5 m/s; The precision of maximum aerodynamic load from low to high is wind profile radar and the forecast of the 4th day to the forecast of the 1st day. The average absolute differences of the maximum aerodynamic load from wind profile radar and the the forecast of the 1st day to the forecast of the 4th day is respectively showed by 326.72 Pa∙rad,126.53 Pa∙rad,162.26 Pa∙rad,183.15 Pa∙rad and 212.59 Pa∙rad,and the correlation coefficient values are separately recorded by 0.76,0.98,0.96,0.95 and 0.92. Therefore,the precision of the maximum aerodynamic load from the wind profile radar is low,which cannot be used for the safety guarantee of rocket flight and needs to be further improved.
The anti-peak circuit of the timing attitude control system of the launch vehicle adopts a "diode+resistor" circuit and a "resistor+diode+voltage regulator diode" circuit. MULTISIM is used for simulation and experimental verification. It is found that the theoretical solenoid valve shutdown time becomes shorter when anti-peak resistance grows larger,and the voltage regulator diode voltage goes larger,separately. Regarding the same electromagnetic valve shutdown time index requirements,a lower reverse voltage produced by using the method of increasing the voltage regulator than using the method of increasing the resistance; Due to the precisely controlling of the flows of fuel and gas that are ensured to be delivered to the engine in the predetermined ratio and time,the boost valve,relief valve and auxiliary power solenoid valve.play an important role of adjusting regulating pressure and protecting safety in the attitude control system,which maintain the stability of the launch vehicle's attitude and flight safety. Therefore,their shutdown time and anti-peak voltage need to be precisely controlled.