No abstract

No abstract

No abstract

This paper considers about the control problem for an underactuated quadrotor UAV system with model parameter uncertainty. Backstepping based techniques are utilized to design a nonlinear adaptive controller which can compensate for the mass uncertainty of the vehicle. Lyapunov based stability analysis shows that the proposed control design yields asymptotic tracking for the UAV's motion in x, y, z direction and the yaw rotation, while keep the stability of the closed loop dynamics of the quadrotor UAV. Numerical simulation results are provided to show the good tracking performance of proposed control laws. I. INTRODUCTIONThe automatic control of a quadrotor UAV is not a straight on mainly due to its underactuated properties [1]. The dynamic model of quadrotor UAV has six degree-of-freedom (DOF) with only four independent thrust forces generated by four rotors. It is difficult to control all these six outputs with only four control inputs. Moreover, uncertainties associate with dynamic model also bring more challenge for control design. Different strategies have been proposed to deal with uncertain quadrotor model, such as adaptive control, neural network based control, sliding mode control, H ∞ control and so on. In [2], a direct adaptive control algorithm was designed for the tracking control of a quadrotor UAV's roll, pitch, yaw angles, together with altitude while compensating for the model parameter uncertainties. A reference system corresponding to a virtual UAV which contains a third order oscillator was utilized to track the desired trajectory. In [3], a backstepping based approach was used for quadrotor UAV control, while two neural networks were used to approximate the uncertain aerodynamic components. By dividing the quadrotor's dynamic model into an underactuated subsystem and a full actuated system, [4] designed a sliding mode controller for the underactuated system and a bounded PID controller for the full actuated system, these two controller drove the UAV to reach a desired position with a desired yaw angle while keep roll and pitch angles zero. More literature review for quadrotor UAV control can be found in [5].One of the main parameter uncertainties associated with the quadoror UAV's dynamic model is the unknown mass

Summary We present an asymptotic tracking controller for an underactuated quadrotor unmanned aerial vehicle using the sliding mode control method and immersion and invariance based adaptive control strategy in this paper. The control system is divided into two loops: the inner‐loop for the attitude control and the outer‐loop for the position. The sliding mode control technology is applied in the inner‐loop to compensate the unmatched nonlinear disturbances, and the immersion and invariance approach is chosen for the outer‐loop to address the parametric uncertainties. The asymptotic tracking of the position and the yaw motion is proven with the Lyapunov based stability analysis and LaSalle's invariance theorem. Real‐time experiment results performed on a hardware‐in‐the‐loop‐simulation testbed are presented to validate the good control performance of the proposed scheme. Copyright © 2014 John Wiley & Sons, Ltd.

A Lyapunov-based control strategy is proposed for the regulation of a Cartesian robot manipulator, which is modeled as a flexible cantilever beam with a translational base support. The beam (arm) cross-sectional area is assumed to be uniform and Euler-Bernoulli beam theory assumptions are considered. Moreover, two types of damping mechanisms; namely viscous and structural dampings, are considered for the arm material properties. The arm base motion is controlled utilizing a linear actuator, while a piezoelectric (PZT) patch actuator is bonded on the surface of the flexible beam for suppressing residual beam vibrations. The equations of motion for the system are obtained using Hamilton’s principle, which are based on the original infinite dimensional distributed system. Utilizing the Lyapunov method, the control force acting on the linear actuator and control voltage for the PZT actuator are designed such that the base is regulated to a desired set-point and the exponential stability of the system is attained. Depending on the composition of the controller, some favorable features appear such as elimination of control spillovers, controller convergence at finite time, suppression of residual oscillations and simplicity of the control implementation. The feasibility of the controller is validated through both numerical simulations and experimental testing.

No abstract

No abstract