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The landing accuracy of a Mars entry vehicle will be degraded duo to uncertain factors in the atmospheric entry process and a novel composite guidance law, having a composite hierarchical framework, is presented to improve the landing accuracy in this paper. It could eliminate the constraint that maximum boundary value of uncertain factors must be known in advance in the multiple sliding surface guidance...
To research the effect on the canard rudder aerodynamic layout for the projectile correction, the steering gear model under different aerodynamic layout was established. Various kinds of aerodynamic parameters were obtained through simulation. Through the establishment of the ballistic model of suitable for less spin correction projectiles, the capability of correcting has been received under the...
In this paper we propose an effective vision-based navigation method that allows a multirotor vehicle to simultaneously reach a desired goal pose in the environment while constantly facing a target object or landmark. Standard techniques such as Position-Based Visual Servoing (PBVS) and Image-Based Visual Servoing (IBVS) in some cases (e.g., while the multirotor is performing fast maneuvers) do not...
In this paper, we propose a revisited form of the so-called Model-Free Control (MFC). Herein, the MFC principle is employed to deal with the unknown part of the plant only (i.e. unmodeled dynamics, disturbances, etc.) and occurs beside an Interconnection and Damping Assignment-Passivity Based Control (IDA-PBC) strategy that is used instead of the PID structure as done in the classical MFC form. Using...
A path optimization strategy for generating energy-aware soaring trajectories for small Unmanned Aerial Systems (sUAS) is presented. Soaring paths are generated using a point-mass dynamics model and deterministic local wind field. The dynamics model, periodic constraints, and an energy-aware cost function are combined into a nonlinear program (NLP) framework to generate energy optimal paths. A dynamics...
This paper presents a computational framework to identify the effects of wind on the dynamics of a quadrotor unmanned aerial vehicle. Then, using the identified model, the strength and the direction of the wind are estimated with the inertial measurements. The proposed approach is based on a geometric numerical integrator on the special Euclidean group, referred to as a Lie group variational integrator...
Pantograph arcing is a more and more prominent phenomenon as the increase of pantograph-catenary interaction, especially when the detachment of pantograph-catenary happens. A large amount of arc models are established on train system in order to analyze the influence of pantograph detachment arcing, but have the limitation of setting the pantograph detachment length to a constant. To solve the problem,...
To solve the ascent guidance of reusable launch vehicle (RLV) under the uncertain condition, a robust guidance method based on combing feedback linearization and H-infinity optimization theory is proposed. The article establishes the RLV ascending dynamic models. According to the characteristics of the ascending flight, the height deviation is converted into a linear relationship with pitch angle...
Guided bombs use different sensors as an input to correct its trajectory to a desired target. Some of them use optical sensors to compute the relative state between the guided system and the target. These systems usually use bang-off-bang controllers to align the line of sight towards the target, producing a quasi-straight path and a fixed attitude angle. The present work proposes an extension of...
In this paper, a control system architecture for control of non-affine in control, open-loop unstable underactuated system is discussed. Passivization of the unactuated (internal) system dynamics achieved through perturbation of trajectories of the actuated states, which are calculated through adaptive dynamic inversion technique, based on Tikhonov's theorem. Performance of the controller is shown...
One of the most challenging problems in aerospace engineering is the analysis of the separation trajectories by which a missile ejected from an aircraft. The attitudes of some static unstable missile are divergent quickly due to aerodynamic interference by the aircraft. Therefore, it is disadvantageous to missile's separation from aircraft safely. The attitude control strategy must be applied to avoid...
There are usually large uncertainties in the aerodynamic parameters of Mars entry vehicles, which inevitably degrades the performance of entry guidance algorithms. The paper presents a backstepping sliding mode controller for drag tracking in Mars entry guidance, which can guarantee the tracking error with finite-time convergence. First, the drag can track the reference trajectory under the virtual...
Entry guidance of a high-lifting vehicle is a complex problem that has attracted the attention of researchers around the world for many years. This paper classifies the previous studies into two categories: trajectory planning-tracking method (TPTM) and predictor-corrector method (PCM). A new trajectory planning method based on the dynamic pressure profile of the vehicle is proposed in this paper...
A method based on variable horizon predictive control is proposed in the paper for nominal trajectory guidance. Firstly, a feasible reference trajectory is generated by the Gauss pseudospectral method. Then, curvature is employed to represent the smoothness of obtained trajectory and predictive horizon is selected according to the curvature. Different predictive control optimal problems are established...
In this paper, a tracking control problem for the unknown longitudinal model of hypersonic flight vehicle is investigated. One remarked advantage is that not only less adjustable parameters are used in the design but also the design is independent of the model. Based on the characteristics of the longitudinal dynamics, The hypersonic flight vehicle system is divided into two subsystems, including...
In this paper, a robust adaptive backstepping control scheme is studied for attitude and altitude control of medium-scale unmanned autonomous helicopter (UAH) with flapping dynamics. A simplified UAH model is established and nonlinear disturbance observer (NDO) is designed to eliminate the effect of unknown external disturbance. The robust adaptive backstep-ping approach is employed to design the...
A predictor-corrector entry guidance method satisfying the constraints of no-fly zone and waypoint is proposed in this paper. First, Gauss pseudospectral method is used to generate a reference trajectory. Based on the reference trajectory some reference points are selected which partition the entry process into several subsections. Then a predictor-corrector guidance law is developed. The trajectory...
Aiming at the improvement of autonomy, adaptability and robustness of the reentry guidance technology, a new predictor-corrector reentry guidance law based on online model identification is proposed under the background of the new generation of reusable aircraft. On the basis of equilibrium glide condition, a feasible control envelope is established to satisfy the reentry constraints. The corresponding...
The PID control technique which is improved by linear extended state observer (LESO) is applied to the design of the flight control system for parafoils with Global Position System(GPS). Firstly, in this paper, the nonlinear dynamics model of the parafoil system is outlined. Then, method of guidance and the theory of LESO is presented in detail. Next, the control system using improved PID control...
Object of this work is hypersonic cruise vehicle which cruises at Mach number beyond 5 in atmosphere. Range of this vehicle is often restricted by the poor aerodynamic, propulsive and structural performances and severe persistent aerodynamic heating. To extend its range, optimal periodic cruise trajectory has been adopted herein to improve fuel efficiency and remit heat accumulation. The performance...
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