The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
For low hitting precision, bad robustness and high normal acceleration of traditional torpedo guidance law, the paper designed anti-torpedo torpedo(ATT) guidance law based on variable structure control. State equation of line of sight angle between ATT and target can be achieved from mathematical model of moving relation between ATT and target torpedo, and designed a variable structure controller...
Three-degree-of-freedom trajectory tracking of the stratospheric airship is investigated. With a simplified planar dynamic model, an adaptive backstepping sliding mode controller is designed to keep the airship to globally asymptotically track a desired trajectory. Lyapunov functions are used to ensure the tracking performance when model parametric uncertainty and external disturbances exist. Simulation...
Model-based predictive control is an effective method for control the large scale systems. Method is based on on-lin solution of control task over the control horizon using current and past measurements as well as the system model. Because model and measurement uncertainty, predicted and plant outputs might be different and plant output may exceed plant output constraints. Generated control is not...
This paper investigates the time-varying formation robust tracking problems for high-order linear multiagent systems with a leader of unknown control input in the presence of heterogeneous parameter uncertainties and external disturbances. The followers need to accomplish an expected time-varying formation in the state space and track the state trajectory produced by the leader simultaneously. First,...
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...
For the trajectory tracking in three degrees of freedom underactuated ships with parameters uncertainties and time-varying disturbances, a robust sliding-mode methodology is proposed. The ship's mass matrices are not assumed to be diagonal, as often required in the literature. Based on the coordinate transformations, the nonzero off-diagonal matrices are turned into the diagonal matrices. The controller...
Constant-Power Load (CPL) introduces destabilizing effect to dc-dc converters, which may lead to voltage oscillation or collapse. To mitigate the destabilizing problem brought by CPL, a nonlinear boundary controller is proposed in this paper, which has a nonlinear switching line. The converters' dynamics on the state space plane is analyzed through phase portrait. The proposed controller is verified...
RGB-D scanning of indoor environments is important for many applications, including real estate, interior design, and virtual reality. However, it is still challenging to register RGB-D images from a hand-held camera over a long video sequence into a globally consistent 3D model. Current methods often can lose tracking or drift and thus fail to reconstruct salient structures in large environments...
We present new methods of simultaneously estimating camera geometry and time shift from video sequences from multiple unsynchronized cameras. Algorithms for simultaneous computation of a fundamental matrix or a homography with unknown time shift between images are developed. Our methods use minimal correspondence sets (eight for fundamental matrix and four and a half for homography) and therefore...
In this paper, we consider the leader-follower consensus problem of multi-agent systems governed by second order dynamics with nonlinear terms. Taking into account the external disturbances, a leader-follower consensus tracking algorithm for each agent with high-order sliding mode control method is proposed to make all the followers track the leader. Then we prove that each agent can follow the leader...
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...
This paper presents a robust control scheme for the tracking control of singularly perturbed uncertain systems. The design problem is divided into two parts: tracking the reference trajectory and enhancing the robustness of the dynamic systems. By using the time-scale techniques, dynamic inversion approach and linear parameter-varying methods, a set of singularly perturbed state feedback controllers...
This paper addresses the problem of trajectory tracking control for an unmanned surface vehicle(USV) with unknown disturbances and input saturation. Let the saturation function is divided into a smooth function and a bounded function, the saturation function can be approximated by smooth function and the bounded function which can be treated as a system uncertainty. An auxiliary design system is employed...
This paper presents nonlinear robust trajectory tracking strategies for the hypersonic vehicle whose ailerons are stuck at an unknown angular position. Firstly, a time-varying sliding mode control strategy for general second-order systems is introduced, and the chattering of sliding mode controller is alleviated. Secondly, the dynamics of hypersonic vehicle are transformed into two second-order systems...
A new exponentially stable nonlinear control law is presented for trajectory tracking, hovering, and yaw motion tracking problems. Since linear motion of quadrotors is achieved via roll and pitch angles, a relationship between roll and pitch accelerations and motion trajectory is developed. An exponentially stable trajectory error dynamics is then formulated to derive the roll and pitch moments and...
The performance in any flight system depends on the feedback control scheme. Therefore, in a first stage, we apply as a basis the so-called Model Free Control (MFC) for the development of nonlinear flight control law that could be implemented without much difficulty. As second step, an in-depth discussion with respect to the control performance is highlighted. Due to the novel form that we propose,...
In this paper, we present a novel notion of input-to-state safety (ISSf) for general nonlinear systems which can be useful for certifying system's safety under the influence of external bounded input (or disturbance) signals. We provide sufficient conditions for ISSf using barrier function/certificate which are analogous to the input-to-state stability Lyapunov function.
In this work we consider a variety of notions related to external stability, i.e., input-to-output stability, for nonlinear systems with time delays. As known for delay-free systems, there are different ways of defining precisely the notions of input-to-output stability that are intrinsically different from each other. The main objectives of this work are to illustrate the relations among the different...
A tractor-trailer wheeled robot (TTWR) is a kind of modular robotic system that consist of the tractor and the trailer are mechanically coupled to each other. It is impossible to obtain an exact dynamics model due to unknown parameters, or unpredictable and irregular features, external disturbance. Because of the non-holonomic constraints property, this paper proposes an adaptive robust cascade controller...
Variable structure filter (VSF) is a robust filter for linear uncertain system. In order to remove the chattering caused by high-frequency gain switching of VSF, the smoothing boundary layer (SBL) has been introduced. And similar to Kalman filter, the optimal state estimation of VSF can be got at the optimal smoothing boundary layer (OSBL). However, in practical applications, the statistical characteristics...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.