Aerodynamics of V/STOL flight , Aerodynamics of V/STOL flight , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی

Aerodynamics of V/STOL flight

Robust adaptive backstepping fast terminal sliding mode controller for uncertain quadrotor UAV

This paper describes a general passivity-based framework for the control of flexible joint robots. Recent results on torque, position, as well as impedance control of flexible joint robots are summarized, and the relations between the individual contributions are highlighted. It is shown that an inner torque feedback loop can be incorporated into a passivity-based analysis by interpreting torque feedback in terms of shaping of the motor inertia. This result, which implicitly was already included in earlier work on torque and position control, can also be used for the design of impedance controllers. For impedance control, furthermore, potential energy shaping is of special interest. It is shown how, based only on the motor angles, a potential function can be designed which simultaneously incorporates gravity compensation and a desired Cartesian stiffness relation for the link angles. All the presented controllers were experimentally evaluated on DLR lightweight robots and their performance and robustness shown with respect to uncertain model parameters. Experimental results with position controllers as well as an impact experiment are presented briefly, and an overview of several applications is given in which the controllers have been applied.

A Unified Passivity Based Control Framework for Position, Torque and Impedance Control of Flexible Joint Robots.

Neural network-based adaptive sliding mode control design for position and attitude control of a quadrotor UAV

This paper investigates the design of a robust controller for the trajectory tracking problem of an under-actuated quadrotor UAV subject to the modeling uncertainties and unknown external disturbances. A new robust nonlinear adaptive controller is proposed for orientation and translation tracking by using the Adaptive Nonsingular Fast Terminal Sliding-Mode Control (ANFTSMC) algorithms. The ANFTSM control law: (i) ensures fast convergence, i.e. the quadrotor outputs achieve to the original values in a short finite-time; ( i i ) avoids singularities; ( i i i ) solves the chattering effect; ( i v ) offers robustness against the unknown external disturbances and uncertainties. Furthermore, the system unknown uncertainty and external disturbances upper bound are coped by the proposed control approach. Online estimation of these upper bounds is only introduced by velocity and position measurements. In addition, the control law applies the Lyapunov theory, guarantees the closed-loop stability of the quadrotor system. Finally, various simulations under different scenarios in terms of external disturbances and parametric uncertainties are carried out to evaluate/emphasize the effectiveness of the ANFTSMC strategy proposed in this work. Moreover, a comparative study is accomplished at the end of the present paper and shows clearly the outperformance of the proposed control scheme.

Robust adaptive nonsingular fast terminal sliding-mode tracking control for an uncertain quadrotor UAV subjected to disturbances

Second order sliding mode controllers for altitude control of a quadrotor UAS

Precision trajectory tracking problem for Unmanned Aerial Systems (UAS) is addressed in this work. A novel algorithm that combines a Nonsingular Modified Super-Twisting Controller with a High Order Sliding Mode Observer to enable an aerial vehicle tracking a desired trajectory under the assumption that i) its translational velocities are not available and ii) there are unmodeled dynamics and external disturbances. The proposed Sliding Mode Controller is based on a nonlinear sliding mode surface that ensures that the position and velocity tracking errors of all system’s state variables converge to zero in finite time. Moreover, the proposed controller generates a continuous control signal eliminating the chattering phenomenon. Finally, simulation results and an extensive set of experiments are presented in order to illustrate the robustness and effectiveness of the proposed control strategy.

Robust Trajectory Tracking for Unmanned Aircraft Systems using a Nonsingular Terminal Modified Super-Twisting Sliding Mode Controller

This paper deals with a load transportation problem using single and multiple quadrotor aerial vehicles A control strategy for cooperative load transportation is developed by using consensus strategies for multi agent systems To reduce the swing in the load angle, the Input Shaping technique is used This technique shows that oscillations can be reduced in up to 60% The stability for the strategy is based on a Lyapunov analysis Finally, simulation results are provide to show the effectiveness of the proposed control structure and the notable reduction of the load swing angle

Load transportation using single and multiple quadrotor aerial vehicles with swing load attenuation

This paper presents the regulation and trajectory tracking for a Micro Coaxial Rocket Helicopter (MCR UAV), as well as the control of a mini aircraft. The former vehicle has the characteristic of performing hover and forward flight while the latter vehicle is considered as an external air transporter for the MCR UAV. For control purposes, the helicopter stabilization is based on sliding mode controllers which avoid the chattering generated during the flight and allow the MCR UAV to perform tracking of smooth trajectories, Furthermore a PD controller stabilizes the aircraft in order to execute semi-autonomous flight. A flight computer for these aerial vehicles consists of a homemade embedded system, low-cost sensors, and signal conditioning circuits, analog filters and actuator. The proposed control algorithms are implemented on the embedded system. Simulation and experimental results show the good performance of the developed system during the flight.

Modeling and Sliding Mode Control of a Micro Helicopter-Airplane System

This paper addresses the development and implementation of a testbed for object's manipulation by using unmanned aerial vehicles AR.Drone and the VICON Cameras System. Such testbed allows the user to choose among two development environments to perform aerial manipulation establishing a communication with LabVIEW, ROS and the C++ Qt library; thus, the user can employ the development environment more suitable for his application. This testbed allows us to establish communication between a computer and the A.R. Drone (v1 or v2) via a WiFi connection which sends and receives data using the communication protocol UDP and sockets for connection with the vehicle UDP ports. This platform sends control and navigation commands to the UAVs in order to position them in the space with user interaction by means of a graphical user interface. This testbed enables the implementation of more complex applications, such as complex controllers. In addition, to validate the effectiveness of this testbed, experimental results of aerial manipulation between two quadrotors are presented.

Eduardo S. Espinoza

Papers

Second order sliding mode controllers for altitude control of a quadrotor UAS

Robust Trajectory Tracking for Unmanned Aircraft Systems using a Nonsingular Terminal Modified Super-Twisting Sliding Mode Controller

Load transportation using single and multiple quadrotor aerial vehicles with swing load attenuation

Modeling and Sliding Mode Control of a Micro Helicopter-Airplane System

Multi-UAV testbed for aerial manipulation applications