scholarly journals A Switching-Based Interference Control for Booster Separation of Hypersonic Vehicle

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Qin Zhong ◽  
Wenbin Wu
Keyword(s):  
Control System ◽  
Flow Field ◽  
Dynamic Pressure ◽  
Variable Structure ◽  
Hypersonic Vehicle ◽  
Separation Process ◽  
Hypersonic Vehicles ◽  
High Dynamic ◽  
Static Instability ◽  
State Changes

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.

RLV Attitude Control System Design in Reentry Flight Phase

2011 ◽  
Vol 383-390 ◽  
pp. 5548-5552
Author(s):  
Peng Fei Ji
Keyword(s):  
Control System ◽  
Attitude Control ◽  
Sliding Mode ◽  
Dynamic Pressure ◽  
Variable Structure Control ◽  
Variable Structure ◽  
Control Technique ◽  
Nonlinear Simulation ◽  
Flight Phase ◽  
Structure Control

In reentry flight phase of reusable launch vehicle (RLV), its aerodynamic characters alter sharply, going with serious uncertainties and nonlinearities. These factors make the reentry attitude control technique be one of key technique for RLV. In this paper, the sliding mode variable structure control technique is used for reentry attitude control. A specific switch function is defined; a specific exponential reaching law and continuous analogy of sign function are chosen to weaken the chattering brought by the variable structure control technique. RLV is equipped with aerosurfaces and reaction control system (RCS), the arithmetic based on dynamic pressure change is presented. Six-freedom nonlinear simulation with great gain and high frequency disturbance proves that the reentry attitude control technique performs very well, and its control accuracy and robustness are brilliant.

scholarly journals Designing Control System of Hypersonic Vehicle with Dynamic Pressure Constraints Considered

2019 ◽  
Vol 37 (1) ◽  
pp. 41-47
Author(s):  
Hongyang Xu ◽  
Yonghua Fan ◽  
Xi Tong ◽  
Jie Yan
Keyword(s):  
Control System ◽  
Optimal Control Theory ◽  
Dynamic Pressure ◽  
Pressure Control ◽  
Hypersonic Vehicle ◽  
State Equations ◽  
Integral Control ◽  
Pressure Control System ◽  
Scramjet Engine ◽  
Simulation Results

An airbreathing hypersonic vehicle(AHV) generally adopts a scramjet engine as its propulsion, which needs strict conditions of flight dynamic pressure. A new dynamic pressure control system is presented, in which the AHV autopilot directly uses dynamic pressure to track the dynamic pressure command. Firstly, the dynamic pressure model of the AHV is established and the state equations of dynamic pressure control are given. Then, the dynamic pressure control system is implemented using the LQR optimal control theory. The dynamic pressure error is augmented in order to add an integral control to track the dynamic pressure with zero steady error. The structure of the dynamic pressure control system is also obtained. The simulation results show that the dynamic pressure control system has a good performance for guaranteeing the dynamic pressure of the scramjet engine with the disturbance of drag and thrust considered.

Suitability of high-dynamic-pressure-treated milk for the production of yoghurt

2004 ◽  
Vol 21 (6) ◽  
pp. 753-760 ◽  
Author(s):  
Rosalba Lanciotti ◽  
Lucia Vannini ◽  
Paola Pittia ◽  
Maria Elisabetta Guerzoni
Keyword(s):  
Dynamic Pressure ◽  
High Dynamic Pressure ◽  
High Dynamic

Grinding Fluid Flow Field Modeling and Multi-Parameter Numerical Analysis Based on Smooth Model

2010 ◽  
Vol 156-157 ◽  
pp. 948-955
Author(s):  
Guang Yao Meng ◽  
Ji Wen Tan ◽  
Yi Cui
Keyword(s):  
Fluid Flow ◽  
Numerical Analysis ◽  
Flow Field ◽  
Dynamic Pressure ◽  
Grinding Wheel ◽  
Lubricating Film ◽  
Fluid Field ◽  
Grinding Fluid ◽  
Smooth Model ◽  
Area Increase

Relative motion between grinding wheel and workpiece makes the lubricant film pressure formed by grinding fluid in the grinding area increase, consequently, dynamic pressure lubrication forms. The grinding fluid flow field mathematical model in smooth grinding area is established based on lubrication theory. The dynamic pressure of grinding fluid field, flow velocity and carrying capacity of lubricating film are calculated by the numerical analysis method. An analysis of effect of grinding fluid hydrodynamic on the total lifting force is performed, and the results are obtained.

Immersion and invariance adaptive finite-time control of air-breathing hypersonic vehicles

2018 ◽  
Vol 233 (7) ◽  
pp. 2626-2641 ◽  
Author(s):  
Chao Han ◽  
Zhen Liu ◽  
Jianqiang Yi
Keyword(s):  
Control System ◽  
Finite Time ◽  
Control Method ◽  
Sliding Mode ◽  
Second Order ◽  
Hypersonic Vehicles ◽  
Terminal Sliding Mode ◽  
Air Breathing ◽  
Immersion And Invariance ◽  
Time Control

In this paper, a novel adaptive finite-time control of air-breathing hypersonic vehicles is proposed. Based on the immersion and invariance theory, an adaptive finite-time control method for general second-order systems is first derived, using nonsingular terminal sliding mode scheme. Then the method is applied to the control system design of a flexible air-breathing vehicle model, whose dynamics can be decoupled into first-order and second-order subsystems by time-scale separation principle. The main features of this hypersonic vehicle control system lie in the design flexibility of the parameter adaptive laws and the rapid convergence to the equilibrium point. Finally, simulations are conducted, which demonstrate that the control system has the features of fast and accurate tracking to command trajectories and strong robustness to parametric and non-parametric uncertainties.

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