Robust Team Formation Control for Quadrotors

Abstract

In this work, we compare between H∞ and Integral Backstepping (IBS) controllers, while they applied to a leaderfollower formation problem of quadrotors. The controllers were used to control the quadrotors with external disturbances and model parameter uncertainties consideration. Nonlinear H∞ design approach is introduced for a general nonlinear affine system to derive a robust controller by solving a Hamilton-Jacobi inequality. Then robustness conditions of the proposed controller are derived via selecting an appropriate parametrised Lyapunov function. The resultant state feedback controller establishes the asymptotically stability of the closed-loop nonlinear system. IBS controller is derived and the stability analysis is achieved via Lyapunov function. Simulation results show a good performance for both controllers in normal circumstance and H∞ controller perform much better than IBS controller in disturbances circumstance. Experimental results of using H∞ controller show its stability and robustness against the disturbances.

Finite‐time fault‐tolerant formation control for multiquadrotor systems with actuator fault

“…wherel denotes the distance from the rotors to the center of mass,c represents the antitorque coefficient. When the control inputs T and are obtained, the desired angular velocity of rotor l, l , can be calculated through (11).…”

“…The aim in this subsection is to compute the desired rotational speed of each propeller in the ith quadrotor. This inversion can be done by simply inverting the matrix given in (11). Taking into account that the magnitude of rotational speed are always positive, a unique solution can be obtained…”

“…Step 1: According to Theorem 3, the propeller speed subsystem of the ith quadrotor (17) under the control law (58) and (59) is finite-time stable, which means that there exists a moment, ie, Γ 11 , such that̃i l = 0 and implies the boundedness of̃i l anḋ̃i l . According to (11), during the interval [0, Γ 11 ], the actual control inputs for position and attitude subsystem is given by…”

Robust time‐varying formation design for multiagent systems with disturbances: Extended‐state‐observer method

“…Note that the desired formation was time‐invariant in References . However, time‐varying formation configurations are required in many applications due to complex external environments and/or variable mission situations.…”

“…Time‐varying group formation control for multiagent systems with directed topologies was showed in Reference . However, further investigates on disturbance rejections of the time‐varying formation with the influence of external disturbances were not considered in References , and the disturbance rejection methods for time‐invariant formations in References cannot be implemented since the expected formation is time‐varying. To the best of our knowledge, robust time‐varying formation design problems for second‐order multiagent systems with unknown external disturbances have not been investigated extensively.…”