Sergio Salazar

Trajectory Control of a Quadrotor Subject to 2D Wind Disturbances

The paper addresses the flight control of a quad-rotor subject to two dimensional unknown static/varying wind disturbances. A model separation is proposed to simplify the control of the six-degrees-of-freedom (6DOF) nonlinear dynamics of the flying robot. Such approach allows to deal with quad-rotor’s 3D-motion via two subsystems: dynamic (altitude and MAV-relative forward velocity) and kinematic (nonholonomic-like navigation) subsystems. In terms of control, a hierarchical control is used as the overall control structure to stabilize the kinematic underactuaded subsystem. A control strategy based on sliding-mode and adaptive control techniques is proposed to deal with slow and fast time-varying wind conditions, respectively. This choice not only provides well tracking control but also improves the estimation of unknown disturbance. The backstepping technique is used to stabilize the inner-loop heading dynamics, such recursive design takes into account a constrained heading rate. Promising simulations results show the validity of the proposed control strategy while tracking a time-parameterized straight-line and sinusoidal trajectory.

Mini Rotorcraft Flight Formation Control Using Bounded Inputs

In this paper, the flight formation control and trajectory tracking control design of multiple mini rotorcraft systems are discussed. The dynamic model of a mini rotorcraft is presented using the Newton-Euler formalism. Our approach is based on a leader/follower structure of multiple robot systems. The centroid of the coordinated control subsystem is used for trajectory tracking purposes. A nonlinear controller based on separated saturations and a multi-agent consensus algorithm is developed. The analytic results are supported by simulation tests. Experimental results include yaw coordination and tracking only.

Flight formation of multiple mini rotorcraft via coordination control

In this paper, the coordination and trajectory tracking control design of multiple mini rotorcraft systems are discussed. The dynamic model of a mini rotorcraft is presented using the Newton-Euler formalism. Our approach is based on a leader/follower structure of multiple robot systems. The centroid of the coordinated control subsystem is used for trajectory tracking purposes. A nonlinear coordinated control design for multiple autonomous vehicle synchronization is developed. The analytic results are supported by simulation tests.

Vision-based Position Control of a Two-rotor VTOL miniUAV

In this paper we address the stabilization of the attitude and position of a birotor miniUAV to perform autonomous flight. For this purpose, we have implemented a Kalman-based sensor fusion between inertial sensors (gyros-accelerometers) and the optical flow (OF) provided by the vehicle. This fusion algorithm extracts the translational-OF (TOF) component and discriminates the rotational OF (ROF). The aircraft’s position is obtained through an object detection algorithm (centroid tracking). Newton-Euler motion equations were used to deduce the mathematical model of the vehicle. In terms of control we have employed a saturated-based control to stabilize the state of the aircraft around the origin. Experimental autonomous flight was successfully achieved, which validates the sensing strategy as well as the embedded control law.

Global stabilisation of the PVTOL aircraft with lateral force coupling and bounded inputs

This work is devoted to prove that the nonlinear control scheme previously proposed by Zavala-Río, Fantoni and Lozano for the global stabilisation of the planar vertical take-off and landing (PVTOL) aircraft with bounded inputs neglecting the lateral force coupling is robust with respect to the parameter characterising such a lateral force coupling, ϵ, as long as such a parameter takes small enough values. In other words, global stabilisation is achieved even if ϵ > 0, provided that such a parameter be sufficiently small. As far as the authors are aware, such a property has not been proved in other existing control schemes when the value of ϵ is not known. The presented methodology is based on the use of embedded saturation functions. Furthermore, experimental results of the control algorithm implemented on a real prototype are presented.

Robust global stabilizing bounded control of a PVTOL aircraft with lateral coupling

Abstract This note provides a detailed stability analysis of a global stabilizing control algorithm for a PVTOL aircraft with lateral coupling (e ≠ 0) and bounded inputs. Such control approach was originally proposed considering e ≠ 0. The analysis furnished here proves the robustness of the original scheme with respect to the existence of lateral coupling. The presented methodology is based on the use of embedded saturation functions and a result of global asymptotic stabilization for cascade systems.