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Path following is a fundamental problem for unmanned air vehicles (UAVs). In this paper, a Lyapunov stable path guidance law is designed to generate the course control command for a small UAV. The control parameters of the guidance law is optimized by the nonlinear model predictive control (NMPC) techinque. The relative simulations with the three different approaches: Lyapunov stable controller with...
To ensure the effectiveness of the RF(Radio Frequency) guided HILS(Hardware-In-the-Loop Simulation) system, the credibility evaluation was necessary. At present, most of the methods were applied in the case of the simulation system input being consistent with the real system input, which is difficult to achieve in some subsystem of the RF guided HILS system. In this paper, the relative complete system...
This paper proposes a nonlinear controller that allows the unmanned air vehicle (UAV) to follow a predefined path. The controller only needs the information of the inertial speed of the UAV and the distance between the vehicle and the desired path. In order to improve the performance of the controller, a parameter of the controller is optimized by using the concept of model predictive control (MPC)...
This paper has presented an implementation of visual based non-GNSS navigation method for small VTOL (Vertically Taking-off and Landing) UAV (Unmanned Aerial Vehicle). A novel method of constructing landmarks is described in detail. It uses a pair of landmarks instead of the general landmark which usually is a single geometry or coding image. The paired-landmark method inherits general landmark methods'...
This paper presents a monocular visual simultaneous localization and mapping (SLAM) system for a small unmanned aerial vehicle (UAV) in GPS-denied environments. A single camera is used to measure the motion of the vehicle and detect features (landmarks) for the map building. The SLAM estimates the positions of the UAV and the features by an extended Kalman filter (EKF), which takes the velocity estimated...
In this paper we present a vision based guidance approach for small unmanned helicopters. The approach is integrated with Hu invariant moments based structural target recognition algorithm for visual acquisition of the target (a helipad) and a guidance model for locating the target. A color filter is designed to eliminate noises from the image by using HSL model. The improved structural target recognition...
This paper has presented an implementation of a RPV control system for a small unmanned helicopter. Both the hardware and the software of the UAV have been described in detail. An EKF-based GPS/INS navigation system is developed with low-cost inertial sensors and a GPS receiver. A chaos-genetic algorithm is proposed in the system identification of the helicopter. A LQG-based RPV (Remotely Piloted...
Focusing on the problem of autonomous flight for a small unmanned helicopter in GPS-denied environments, this paper proposes a navigation system which combines monocular visual and inertial measurements. The homography based visual odometry, as well as the inertial measurement from an IMU, can estimate the motion of a small unmanned helicopter. An extended Kalman filter is used to fuse the estimations...
This paper proposes a nonlinear controller that allows the unmanned air vehicle (UAV) to follow a predefined path. The controller only needs the information of the inertial speed of the UAV and the distance between the vehicle and the desired path. In order to improve the performance of the controller, a parameter of the controller is adjusted by a fuzzy logic rule. Lyapunov stability arguments are...
In this paper, a fuzzy-based threshold method is proposed in image processing of SIFT which is used in visual navigation of small UAVs. By adjusting the thresholds of SIFT online fuzzily, it provides a stable number of features detected from aerial image sequence. The visual navigation estimates the motion of the small UAV by tracking and matching these features extracted from the consecutive image...
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