Thrust Vector Control Research Articles

Керування вектором тяги шляхом вдува продуктів детонації в надзвукову частину сопла

To solve the problem of satellite control and stabilization in emergencies, it is proposed to use a detonation rocket engine, which enables active maneuvering to avoid a collision with space debris. The goal of this work is to study a new way of rocket engine thrust vector control by acting with a detonation shock wave on the gas flow in the nozzle. A detonation wave in a supersonic flow in a nozzle was numerically simulated. The simulation was conducted in a non-stationary plane formulation at different angles of inclination of the detonation gas generator that initiates a detonation shock wave to the combustion chamber axis with the use of SolidWorks application software for the 11D25 engine of the Cyclone-3 third stage. The simulation results were used to pre-optimize the location of the detonation gas generator on the nozzle wall. It was found that the effect of the detonation wave on the main gas flow in the nozzle is caused by two force factors: the first is due to the reactive force produced by the detonation product injection into the nozzle and a high-pressure zone on the wall where the detonation gas generator is mounted, and the second is due to a change in pressure distribution over the nozzle surface. In order to increase the effect of the shock wave, the detonation products must be injected parallel to the main gas flow in the nozzle or at some angle. The simulation showed the drawbacks and advantages of detonation product injection at different angles. The detonation wave effect on a supersonic nozzle flow was studied experimentally. A system was developed to record the shock detonation wave propagation using a heat meter. A special nozzle model and a gas generator were developed to initiate a detonation wave interacting with a supersonic air flow. It was found out how the detonation wave separates the main flow from the nozzle walls in the overexpanded mode. The results may be used in the space-rocket industry to provide upper stage maneuvering to avoid a collision with space debris.

Fluidic Thrust Vector Control of Aerospace Vehicles: State-of-the-Art Review and Future Prospects

Abstract An efficient propulsion system holds the key to the smooth operation of any aerospace vehicle over different flight regimes. Apart from generating the necessary thrust, emphasis has also been laid on vectoring the direction of thrust. The primitive modes of thrust vectoring chiefly focused on mechanical means such as the use of gimbals or hinges. The current state-of-the-art technologies demand more efficient methods for thrust vectoring, which minimize the use of mechanical components. These methods termed fluidic thrust vector control methods, employ secondary jets for achieving the required attitude, and trajectory of the aerospace vehicles such as aircraft, rockets, and missiles. Such methods have greatly helped in reducing vehicle weight, vehicle maintenance requirements, and enhancement of stealth characteristics of such vehicles. This work presents a review of the various fluidic thrust vectoring systems, starting with a brief overview of traditional thrust vectoring systems, followed by a discussion on the various aspects of fluidic thrust vectoring systems. It also highlights the effect of the various geometrical and operating conditions on the performance parameters of the thrust vectoring system such as the thrust vector angle, system thrust ratio, and thrust vectoring efficiency among others. For ensuring the comprehensive character of this work, synthetic jet vectoring techniques have also been included due to their nonmechanical nature and similarities with purely fluidic thrust vectoring techniques.

Study on Double-Resonant Characteristics of Load Simulation System for Electro-Hydraulic Servo Mechanism

The electro-hydraulic servo mechanism and engine realize thrust vector control together. Due to the low natural frequency of the engine, the dynamic characteristics of the test process show the result of double-resonance. The load simulation system can improve the efficiency of production tests and replace the actual engine in the production process. This paper fully considers the resonant problem of the engine, gives the relevant structural design scheme and parameter adjustment method to the load simulation system, and tests and analyzes the resonant characteristics. It aims at changing the resonant characteristics of the load simulation system by designing and adjusting the connection stiffness and torsional stiffness to achieve the real load condition.

Thrust Vector Controller Comparison for a Finless Rocket

The paper focuses on comparing applicability, tuning, and performance of different controllers implemented and tested on a finless rocket during its boost phase. The objective was to evaluate the advantages and disadvantages of each controller, such that the most appropriate one would then be developed and implemented in real-time in the finless rocket. The compared controllers were Linear Quadratic Regulator (LQR), Linear Quadratic Gaussian (LQG), and Proportional Integral Derivative (PID). To control the attitude of the rocket, emphasis is given to the Thrust Vector Control (TVC) component (sub-system) through the gimballing of the rocket engine. The launcher is commanded through the control input thrust gimbal angle δ, while the output parameter is expressed in terms of the pitch angle θ. After deriving a linearized state–space model, rocket stability is addressed before controller implementation and testing. The comparative study showed that both LQR and LQG track pitch angle changes rapidly, thus providing efficient closed-loop dynamic tracking. Tuning of the LQR controller, through the Q and R weighting matrices, illustrates how variations directly affect performance of the closed-loop system by varying the values of the feedback gain (K). The LQG controller provides a more realistic profile because, in general, not all variables are measurable and available for feedback. However, disturbances affecting the system are better handled and reduced with the PID controller, thus overcoming steady-state errors due to aerodynamic and model uncertainty. Overall controller performance is evaluated in terms of overshoot, settling and rise time, and steady-state error.

Path-Following Control for Thrust-Vectored Hypersonic Aircraft

Thrust vector control (TVC) might be used to control aircraft at large altitudes and in post-stall conditions when aerodynamic control surfaces are ineffective. This study demonstrated that the implementation of the TVC on high-speed aircraft is a reasonable solution and might be an alternative when compared to the complicated reaction control system or large aerodynamic control surfaces. The numerical flight dynamics model of the X-15 experimental aircraft was developed and implemented in MATLAB/Simulink and then used to investigate the proposed solution. The obtained results indicate that the aircraft, equipped with full 3D thrust vectoring and two independent horizontal stabilizers to control the roll angle, was able to achieve flight along the path that was defined by a set of waypoints. This paper also highlights the potential benefits and challenges of using TVC as a control method for aircraft. The results of this study contribute to the growing body of research on aircraft control and simulation. Future work can explore the use of TVC for other aircraft with unique configurations and low maneuverability features.

Research on Multi-axis Synchronous Test Technology based on GLINK Bus

As a rocket engine for thrust vector control system of high reliability and redundancy, high precision, and the requirements of lightweight, servo system for test system can quickly test a certain level and fast data processing of the test location, transient, and frequency characteristic indexes, a rocket motor thrust vector control system using GLINK as control bus. Moreover, the first level servo is an all-in-one machine with four drives and controls, so the test system is required to have the ability to control and test four actuators simultaneously under the GLINK main line. This paper discusses the hardware knowledge of the test system based on the GLINK bus: GLINK bus technology, communication topology of GLINK station card and network card; software function of the test system; multi-axis synchronous test function, and synchronous data processing function developed by LabVIEW.

Parameters to Assess the Operation of Thrust Vector Control Systems in Jet Engines

This paper discusses the parameters for evaluating the effectiveness of various methods of controlling the thrust vector of jet engines. An approach to the multi-parametric optimization of the nozzle structure and the parameters of jet injection into the supersonic flow is developed. The approach is based on a numerical model for a turbulent flow of a viscous compressible gas. A classification of parameters is proposed for evaluating methods for controlling the thrust vector of jet engines.

Thrust Vectoring Control of a Novel Tilt-Rotor UAV Based on Backstepping Sliding Model Method.

In this paper, a control method of a novel tilt-rotor UAV with a blended wing body layout is studied. The novel UAV is capable of vertical take-off and landing and has strong stealth capabilities that can be applied to carrier-borne reconnaissance aircraft. However, the high aspect ratio of blended wing body UAVs leads to a wingtip or oar-tip touchdown problem when adopting the conventional position-attitude control (CPAC) scheme with a large crosswind disturbance. Moreover, when the UAV is subject to interference during reconnaissance, aerial photography, and landing missions, the conventional scheme cannot provide both attitude stability and track accuracy. First, a direct thrust vectoring control (DTVC) scheme is proposed. The control authority of the rotor tilt mechanism was added to enable the decoupling of the attitude and trajectory and to improve the response rate and response bandwidth of the flight trajectory. Second, considering the problems of strong couplings and parameter uncertainties and the nonlinear features and mismatched perturbations that are inevitable in the tilt-rotor, we designed a robust UAV controller based on the backstepping sliding mode control method and determined the stability of the control system through the Lyapunov function. Finally, in the case of crosswire interference during vertical takeoff and landing and the aerial photography missions of the UAV, the numerical simulation of the CPAC scheme and the DTVC scheme was carried out, respectively, and the Monte Carlo random test method was introduced to conduct the statistical test of the landing accuracy. The simulation results show that the DTVC scheme improves the landing accuracy and speed compared to the CAPC scheme and decouples the position control loop from the attitude control loop, finally enabling the UAV to complete the flight control in the VTOL phase.

Numerical Investigation on the Thrust Vectoring Performance of Bypass Dual Throat Nozzle

Modern aircraft and missiles are gradually integrating thrust vector control systems to enhance their military capabilities. Bypass Dual-Throat Nozzle (BDTN) control is a new fluidic thrust vectoring technique capable of achieving superior performance with large vector angles and low thrust loss. In this study, we analyzed the flow characteristics and performance parameters of BDTN by varying the bypass angle, nozzle convergence angle, and bypass width. The flow governing equations are solved according to a finite volume discretization technique of the compressible RANS equations coupled with the Renormalization Group (RNG) k-ϵ turbulence model for Nozzle Pressure Ratio (NPR = 2~10) to capture the significance of under-expanded and over-expanded jets. Results show that by decreasing the bypass angle from 90° to 35°, there is a 6% increase in vectoring angle while the vectoring efficiency is enhanced by 18%. However, a decrease of 3% in the thrust and discharge coefficients is also observed. When the convergence angle was increased from 22° to 37°, vectoring angle, discharge coefficient, and thrust coefficient increased by 2%, 1%, and 0.26%, respectively. Moreover, vectoring efficiency is also enhanced by 8% by reducing the convergence angle from 37° to 22°. Based on the investigated parameters, it is determined that nozzle convergence angle does not significantly influence thrust vectoring performance, however, bypass width and bypass angle have a significant effect on thrust vectoring performance.

Improved Gust Tolerance of a Cyclocopter UAV Using Onboard Flow Sensing

This paper describes the gust rejection study of a twin-cyclocopter micro air vehicle with two cyclorotors and an anti-torque nose rotor. A gust rejection controller relying on velocity feedback and onboard flow sensing was implemented in a closed-loop feedback system. Tethered experiments were conducted with the vehicle mounted on a 6-DOF stand in front of a synthetic gust generation device capable of providing up to 4 m/s step gust input. Planar gusts along the longitudinal and lateral axis of the cyclocopter and crosswinds were systematically studied. Both pitch control (varying nose rotor rpm) and thrust vectoring control strategies were evaluated to counteract perturbation along the longitudinal axis, while the cyclocopter used differential rotational speed of the cyclorotors for lateral gusts. Results showed that thrust vectoring was more effective than pitch control in reducing displacement from gust. Pitch control using the position feedback controller resulted in a maximum gust tolerance of 2.8 m/s with a duration of 3 s. while thrust vector control using the combined flow feedback and position feedback controller was able to withstand 4 m/s step gust input with 1 s duration with only 0.01 m displacement. In addition, flow feedback was more effective than position feedback in minimizing position error. The cyclocopter was also able to mitigate step gusts of 2.8 m/s in magnitude and 3 s duration with crosswind components at 30 deg from the longitudinal axis. The difference in performance can be attributed to the cyclocopter's unique thrust vectoring capability.

Feasibility of a Morphing Rocket Nozzle for Thrust Vector Control based on Corrugated Composite Laminates

The paper presents technological, experimental and numerical studies aimed at the development of a morphing nozzle in composite material with a deformable divergent section, which is designed to control the vector of thrust in rockets without using mechanisms or localized flexible joints. The nozzle design is characterized by corrugated composite walls and longitudinal elements that make possible a separation of load paths involved in bending response, bearing of internal pressures and related force resultants. Mechanical requirements and conditions of pressure, temperature and gas velocity in the morphing part of the nozzle are defined by selecting and investigating two potential application scenarios. Thereafter, both technological aspects and the assessment of mechanical performances are addressed by designing, manufacturing and testing a composite demonstrator with morphing capabilities. A lightweight and flexible thermal protection system is proposed, designed and numerically analyzed. Finally, a virtual demonstrator of the composite morphing nozzle is developed. Results point out the possibility of manufacturing composite elements with axial load bearing capability that may undergo significant bending deformation without failures. The integration of a flexible thermal protection systems leads to a promising concept for the development of innovative morphing nozzle for rocket engine applications.

Computational study of gas flow characteristics when using intra-nozzle interceptors for thrust vector control

This article proposes the use of cylindrical nozzle interceptors (probes) as an alternative method of rocket engine thrust vector control, which can replace traditional thrust vector control systems. The objective of this paper was to perform a three-dimensional CFD simulation of the gas flow in a rocket engine nozzle with a rod interceptor taken out of the wall without secondary injection, analyzing the calculated flow data and estimating the lateral force. The simulations will be performed in steady-state mode. In the CFD simulations, velocity distribution contours were obtained on the symmetry plane for all positions and values of the interceptor height.

A prescribed time attitude control method based on thrust vector control (TVC) nozzle for solid propulsion satellite

With the development of on-orbit missions, solid propulsion technology is applied to the rapid orbital maneuver of satellites. During solid propulsion maneuver, the position change of the mass center caused by the fuel consumption and the installation error of thruster have brought serious attitude disturbances. For this problem, a novel prescribed time attitude control method is proposed in this paper. Firstly, a dynamics model of the solid propulsion micro-satellite is established, while the thrust direction is adjusted by the thrust vector control (TVC) nozzle. Then, a constraint boundary function is constructed to characterize the strict fixation of the thruster operating time and an adaptive fuzzy observer is developed to quickly estimate the lumped model uncertainties. Using the backstepping method, a novel prescribed time attitude control strategy regardless of initial conditions is designed. Simulation results show that the designed controller can achieve the prescribed time convergence of satellite attitude during solid propulsion orbital maneuver, effectively.

Analysis of load-bearing safety and reliability of solid rocket motor flexible joint structure

Flexible nozzle is the thrust vector control system of a solid rocket engine, and flexible joint is the key component of its load-bearing and changing behavior. It is composed of composite rubber elastic parts with spherical annular structure and metal reinforcing parts with spherical annular structure alternately adhesive. Under the action of complex loads, the flexible nozzle exhibits highly nonlinear mechanical properties. The traditional flexible joint structure with uniform thickness is easily damaged during loading and has large negative mass and short system range. However, the load-bearing swing performance of the system, such as swing center displacement, swing moment, and fatigue life, is difficult to predict, and the safety and reliability of the joint structure cannot be guaranteed. To this end, on the basis of the measured material properties of elastic parts, the Lagrangian structural dynamics algorithm coupling material and geometrically nonlinear, the Design of Experiment multi-objective optimization algorithm and the multi-axial stress fatigue finite element numerical calculation method based on crack propagation combined to design a new lightweight variable-thickness joint. From the mechanical point of view, the failure mechanism and mode of the two joint structures are compared and analyzed, the safety factor is determined, and the load-bearing swing performance of the system is predicted. Results of the ground experiment test of the system prove that variable-thickness flexible joint has better safety and reliability.

Fluidic Thrust, Propulsion, Vector Control of Supersonic Jets by Flow Entrainment and the Coanda Effect

Thrust, propulsion, vector control of supersonic jets has been applied to jet and rocket engines, ejectors, and other many devices. In general, there are two approaches to this type of control, namely mechanical moving systems and fluidic thrust vector control systems without moving parts, with mechanical moving systems being the most common. However, generally speaking, these systems are very complicated, and more simple methods and devices are desired. In this study, an extremely simple method for the thrust vector control of a supersonic jet by a fluidic Coanda nozzle (FC-nozzle) using the entrainment of the surrounding fluid and Coanda effect is newly proposed. The FC-nozzle consists of a pipe nozzle (Pi-nozzle), spacer, and linearly expanded Coanda nozzle (Co-nozzle) with eight suction pipes (Su-pipes) installed to surround the jet from the Pi-nozzle. The jet from the Pi-nozzle flows straight with the entrainment flow of the surrounding fluid. When some Su-pipes are closed, the pressure between the jet and Co-nozzle wall decreases, and subsequently, the jet deflects to the closed side of the Su-pipe and reattaches to the wall by the Coanda effect. The flow characteristics and deflection characteristics of the supersonic jet from the FC-nozzle are examined by the visualized flow pattern using the Schlieren method and measurements of the velocity distribution. As a result, it is shown that by changing the number of Su-pipes and the locations at which they are closed, the deflection angle and circumferential position of the jet from the Pi-nozzle can be easily controlled.

Concept and design of a hall-effect thruster with integrated thrust vector control

Hall-effect thrusters (HETs) are among the most commonly used propulsion systems for attitude and orbit control of satellites. As an arrangement in a cluster or individually, equipped with a mechanical suspension, thrust in all three spatial directions can be generated, but requires additional mechanisms and components. Therefore, the Technische Universität Dresden (TU Dresden) is currently working on a concept for developing a Hall-effect thruster with integrated thrust vector control, which would allow steering in all three spatial directions with just a single thruster. This new concept is intended to work solely by influencing the ion beam and should not have any additional mechanical components. The HET will come with a segmented anode to set different electrical potentials at the anode and cause an inhomogeneous distribution of the electric field within the discharge channel, which results in an inhomogeneous force vector distribution at the exit plane. It is assumed that this will generate turning moments around the center of gravity. Deliberately causing those turning moments can therefore be used for steering with just one thruster. This work presents the concept of the propulsion system, gives an outlook on the advantages of its technology and shows capabilities for space applications.

Design of BLDCM servo controller based on TMS320F28377D

To meet the application requirements of high-precision and fast-response thrust vector control from a solid rocket motor, a digital and integrated servo controller for four brushless direct current motors was designed and implemented. The controller hardware system proposed in this paper includes control circuit module and drive circuit module. The former mainly includes power conversion circuit, DSP system circuit, A/D circuit, SPI communication interface circuit, and SCI communication interface circuit. The later mainly includes three-phase full-bridge six-arm drive circuit and optocoupler isolation circuit. The three closed-loop control strategies of position, speed and current based on PID control algorithm are adopted, and the mathematical model of the motor is established in Matlab/Simulink for verification. The structure composition and working principle of the servo controller are briefly introduced, and the hardware design scheme, software workflow and control strategy are described in detail. Experimental results show that the response speed and control accuracy of the proposed controller meet the technical requirements.

Sliding-Mode Control and Strategic Thrust-Vectoring Based Aircraft Flat Spin Recovery With Altitude Loss Minimization

Spin recovery from a fully-developed-oscillatory-stable-flat spin is performed in this article using thrust vector control (TVC) and compared with the conventional mode of recovery. TVC dynamics is modeled and then added to the standard aircraft dynamics. TVC command is designed as a function of angle of attack in the pitch and yaw direction and optimally used with aircraft primary controls (APCs). The APC is designed using the sliding-mode control technique. The spin recovery profile is demonstrated on F-18 high alpha research vehicle to test the efficacy of the proposed algorithm. Results show that with the combined strategic use of TVC and APC, spin recovery time is drastically reduced because of reduced saturation of APC. Thus, altitude decrease during spin recovery also reduces, thereby gaining on final exit altitude to level flight, compared to recovery using only APC. Thus, TVC is proven in this article to be a powerful corrective contributor to spin recovery, increasing margin of safety in terms of excessive altitude loss.

Dual Synthetic Jets Actuator and Its Applications—Part II: Novel Fluidic Thrust-Vectoring Method Based on Dual Synthetic Jets Actuator

A novel fluidic thrust-vectoring (FTV) control method based on dual synthetic jets actuator (DSJA) is proposed and evaluated. Numerical simulations are governed by the compressible Unsteady Reynolds-Averaged Navier–Stokes (URANS) equations. According to the results, DSJA is capable of deflecting a primary jet with a velocity of 100 m/s and a height of 50 mm by approximately 18 degrees with a momentum coefficient of 1.96%. It produces comparatively linear control characteristics in almost all deflection angles evaluated (0~23 degrees). The low pressure generated by DSJA, the ejecting enhanced by DSJA, and the co-flow effect produced by the accelerated secondary jet all play roles in the deflection of the primary jet. Since the primary jet is strong enough, the potential of DSJA to provide thrust vector control is revealed.

Experimental Investigation on Jet Vector Deflection Jumping Phenomenon of Coanda Effect Nozzle

The Coanda effect nozzle is a fluid thrust vectoring technology that uses the Coanda effect to control jet vector deflection. The jumping phenomenon often occurs in the process of controlling jet vector deflection. This phenomenon leads to the nonlinearity of thrust vector control. It destroys the control performance of the aircraft and brings potential dangers to the safety of the aircraft. The jumping phenomenon occurs in an unsteady flow field different from the traditional flow phenomenon. The flow structure in an unsteady flow field changes with time, so it is not easy to control by the traditional active flow control method. This paper explains the reasons for the jumping phenomenon from two aspects: flow field stability and flow structure. Secondly, the unsteady flow field with the jumping phenomenon is studied and analyzed by a flow visualization experiment and dynamic force measurement. Furthermore, the dynamic modal decomposition (DMD) method is used to extract the characteristic frequencies of the critical vortices causing jets to jump in unsteady flow fields. Finally, a pulsed jet with the same characteristic frequency is used to control the varying vortices in the unsteady flow field. The experimental results show that the active flow control method, which extracts the characteristic frequency of the critical flow field structure by DMD, effectively suppresses the jumping phenomenon in the unsteady flow field. It also linearizes the process of jet nonlinear vector deflection.