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The positional inaccuracies associated with the GPS/INS measurements make the terminal phase of the normal GPS/INS landing system imprecise. To solve this problem, an adaptive fuzzy data fusion algorithm is developed to obtain more accurate state estimates while the vehicle approaches the landing surface. This algorithm takes the translational displacements in x and y from the mounted Optical Flow...
Quadrotors, like any dynamical system, are subjected to model uncertainties which may cause instability and inaccuracy in navigation. In addition, the presence of input constraints violates the affine property which, as a result, adds additional challenges and complicates designing the control system for quadrotors. In this paper, an adaptive nonlinear control algorithm is designed to overcome these...
This paper presents a new approach for navigating a quadrotor over undulated terrains that can be of great importance for the use of unmanned aerial vehicles in civilian applications such as monitoring of pipes, bridges and buildings. The proposed approach involves the use of a single-beam LiDAR to estimate the terrain profile under uncertainty. The LiDAR is installed at the base of a quadrotor and...
A switching nonlinear control system consisting of multiple Lyapunov functions and an adaptive mechanism is considered for small quadrotors. A typical quadrotor has only four actuators and six degrees of freedom (DOF) which makes it an under-actuated system. Underactuation adds constraints to the control input and complicates designing the control system. In addition, quadrotor control systems suffer...
Payload add or drop occurs commonly in various quadcopter applications. Generally the control parameters of the onboard autopilot or stabilizer are tuned for a particular condition such as no payload or constant payload. Therefore, such mass change may significantly deteriorate the automatic control performance. In our work, a robust adaptive control method is proposed to deal with this challenging...
This paper presents a new methodology to estimate the orientation of a quadrotor using single low cost IMU sensor. The proposed solution uses two extended Kalman filters (EKF) along with a Direction Cosine Matrix (DCM) algorithm. An EKF is used to filter the noise signal of the angular rates measured by a 3-axis gyroscope sensor. Subsequently, a DCM algorithm uses the filtered gyro signal along with...
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