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Formation-containment analysis and design problems for high-order linear time-invariant swarm systems with directed interaction topologies are dealt with respectively. Firstly, protocols are presented for leaders and followers respectively to drive the states of leaders to realize the predefined time-varying formation and propel the states of followers to converge to the convex hull formed by the states of leaders. Secondly, formation-containment problems of swarm systems are transformed into asymptotic stability problems, and an explicit expression of the formation reference function is derived. Sufficient conditions for swarm systems to achieve formation containment are proposed. Furthermore, necessary and sufficient conditions for swarm systems to achieve containment and time-varying formation are presented respectively as special cases. An approach to determine the gain matrices in the protocols is given. It is shown that containment problems, formation control problems, consensus problems and consensus tracking problems can all be treated as special cases of formation-containment problems. Finally, numerical simulations are provided to demonstrate theoretical results. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Robust attitude control problem for small-scale unmanned helicopters is investigated to improve attitude control performances of roll and pitch channels under both small and large amplitude manoeuvre flight conditions. The model of the roll or pitch angular dynamics is regarded as a nominal single-input single-output linear system with equivalent disturbances which contain nonlinear uncertainties, coupling-effects, parameter perturbations, and external disturbances. Based on the signal compensation method, a robust controller is designed with two parts: a proportional-derivative controller and a robust compensator. The designed controller is linear and time-invariant, so it can be easily realised. The robust properties of the closed-loop system are proven. According to the ADS-33E-PRF military rotorcraft standard, the controller can achieve top control performances. Experimental results demonstrate the effectiveness of the proposed control strategy. [ABSTRACT FROM AUTHOR]

Time‐varying formation control problems for high‐order linear time‐invariant swarm systems with switching interaction topologies are investigated. A general formation control protocol is proposed firstly. Then using a consensus based approach, necessary and sufficient conditions for swarm systems with switching interaction topologies to achieve a given time‐varying formation are presented. An explicit expression of the time‐varying formation reference function is given. It is revealed that the switching interaction topologies have no effect on the formation reference function and the motion modes of the formation reference can be specified. Furthermore, necessary and sufficient conditions for formation feasibility are presented. An approach to expand the feasible formation set is given and an algorithm to design the protocol for swarm systems with switching interaction topologies to achieve time‐varying formations is provided. Finally, numerical simulations are presented to demonstrate theoretical results. [ABSTRACT FROM AUTHOR]

Abstract: This paper deals with the attitude tracking control problem for a three degree-of-freedom laboratory helicopter, which aims to improve tracking control performances of elevation and pitch channels. The model of each channel is considered as a linear system with equivalent disturbances which contain nonlinear uncertainties, coupling effects, parameter perturbations, and external disturbances. A state-feedback controller is applied to the linear model and a robust compensator is introduced to restrain the effects of equivalent disturbances. The robust properties of the closed-loop control system with the proposed controller are shown better than the standard controller. Experimental results demonstrate the improved performances of the proposed control strategy. [Copyright &y& Elsevier]

This study presents a controller design method to achieve the robust attitude control for uncertain quadrotors. The proposed linear time‐invariant controller consists of a proportional–derivative (PD) controller and a robust compensator. The PD controller is designed for the nominal linear system to achieve the desired tracking and the robust compensator is added to restrain the influence of the uncertainties. It is proven that attitude tracking errors are bounded and the boundaries can be made as small as desired. Experimental results on the quadrotor are given to confirm the effectiveness of this control method. [ABSTRACT FROM AUTHOR]