Whether launching from the ground or in the air, hypersonic vehicles need the booster to accelerate to a predetermined window, so as to meet the requirements of scramjet engine ignition. Therefore, there is interference suppression between boosters and hypersonic vehicles under the high dynamic pressure, which has become a key technical problem that affects the success of flight tests, especially when the aircraft is statically unstable. A method of variable structure switching‐based control is proposed in this paper for rapid suppression on hypersonic vehicle booster separation interference. Switching control systems in real time according to state changes caused by flow field interference, the method can keep the attitude stability of hypersonic vehicle booster separation under the high dynamic pressure of static instability. The aerodynamic calculation model of the hypersonic vehicle booster separation process is established first, which adopts an unsteady solution and clarifies the aerodynamic interference characteristics of the afterbody on the vehicle in booster separation. Then, according to the characteristics of the flow field, the dynamics of the vehicle in and out of the interference area are converted into subsystems with switching characteristics. Using the dimension reduction and variable structure method, the switching control surface of the control system is established. On the basis of the vehicle state changes caused by flow field, the control system on the orbital change surface can be switched in real time to achieve stable attitude in the process of separation interference. Meanwhile, considering the additional interference torque generated by the afterbody to the vehicle in the separation process, a control system for interference suppression of the booster separation is designed. Simulation results verify that the designed control system can rapidly suppress the booster separation interference when the dynamic pressure is about 150 kPa and the vehicle has the static instability of 5%, thereby realizing the stable attitude of the vehicle.
For hypersonic-vehicle fairing separation, the reliable separation of the fairing and rapid suppression of the separation disturbance are required in scenarios where there is high dynamic pressure and there are abrupt changes in the aerodynamic shape of the aircraft as well as overall parameters. A switching-based control method is proposed in this paper for the interference suppression of hypersonic-vehicle fairing separation, aiming to ensure the stability of the control system in cases of abrupt changes in the controlled object. First, an unsteady-flow calculation method is adopted to clarify the aerodynamic interference characteristics of the aircraft in fairing separation, and the aerodynamic calculation model of the hypersonic-vehicle fairing-separation process is established; then, two states of the aircraft, with and without fairing, are transformed into a subsystem with switching characteristics. The attitude-stability problem in the fairing-separation process is transformed into a problem of solving the arbitrary switching of the switched system by using the linear matrix inequality (LMI) approach. Meanwhile, the control system for interference suppression of the fairing separation is designed by considering the aerodynamic interaction of the fairing movement with the aircraft during the separation. The simulation results showed that the designed control system can realize the reliable separation of the fairing under high dynamic pressure and effectively suppress interference in the separation process.
16 August 2020 in International Journal of Electrical Engineering & Education
A strategy of intercepting the near-space hypersonic aircraft is proposed, which is based on infrared window guidance, change the guidance law from side window constraint to the fixed lead angle, the sliding mode variable structure guidance law with prefix angle constraint is designed. First, setting up the dynamic model for the end of interceptor with direct force/aerodynamic control, deriving the integrated mathematical model of interceptor’s longitudinal guidance and control. Then, by using smooth sliding mode control, the interceptor’s variable structure guidance law with prefix angle constraint is designed. Last, the simulation results show that the designed guidance law can achieve high precision interception for hypersonic vehicle.
14 January 2021 in International Journal of Electrical Engineering & Education
Hypersonic vehicles often use the aerodynamic configuration and light materials such as lifting body and waverider, which leads to the unmatched uncertain control problems caused by strong coupling characteristics and interference during reentry. To solve these problems, firstly, this paper analyzes the key factors and uncertainties that affect the attitude motion of hypersonic vehicle. Secondly, it studies the modeling and verification of rigid body and elastic body of hypersonic vehicle, establishes the error model with disturbance observation compensation, and proposes a new attitude control scheme of hypersonic vehicle, which realizes the stable tracking of attitude angle and improves the uncertainty of key parameters of the system. The simulation results show that the performance index meets the requirements and has good robust performance in the presence of unknown disturbance.