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Summary: In this study, the problem of preview tracking control (PTC) was considered with regard to the linear parameter periodic systems (LPPSs) subject to previewed signals. First, the difference operator approach was extended to derive an augmented error system (AES). As a result, the PTC problem was transformed into a stabilization problem via state/output feedback. Second, sufficient conditions guaranteeing the closed‐loop stability of the augmented error systems were derived, and the design of a periodic controller with preview actions was proposed through the approach of linear matrix inequalities (LMIs). Finally, a numerical simulation was performed to illustrate the effectiveness of the proposed periodic controller. [ABSTRACT FROM AUTHOR]

In this paper, the constrained control of systems evolving on matrix Lie groups with uncertainties is considered. The proposed methodology is composed of a nominal Model Predictive Control (MPC), and a feedback controller. The previous work on the control of systems on manifolds is applied to design the nominal MPC, which generates the nominal trajectory. In the nominal MPC, the state and input constraints on the Lie group are transformed into the constraints on the Euclidean space. While to deal with uncertainties, the feedback control used to track the nominal trajectory is designed directly on the Lie group. The tracking error in the feedback control is proved to be bounded in invariant sets, which are further used to revise the constraints in nominal MPC. We prove that the input‐to‐state stability of the entire system under the proposed control methodology with respect to the disturbances can be achieved. The proposed methodology is applied to the constrained attitude control of rigid bodies with uncertainties. In the application example, the detailed mathematical proof and the comparative numerical simulation are presented to demonstrate the feasibility of the proposed methodology. [ABSTRACT FROM AUTHOR]

In this paper, a protocol for nondestructive parity meter (NPM) of two cat‐state qubits is proposed. The physical model contains two cavities and an auxiliary qubit. For each cavity, the quantum information is encoded on the odd and even cat state, forming a cat‐state qubit. By adjusting the strength of the driving field on the auxiliary qubit, an effective Hamiltonian for cavity‐selective transition is derived. Moreover, reverse engineering based on the effective Hamiltonian is applied to find the evolution path, and the systematic‐error‐sensitivity nullification method is used to select proper parameters of the evolution path. In this way, robust control fields are designed to combat the influence of the systematic errors. Furthermore, the effects of random noise and decoherence on the fidelity of the protocol are considered. Numerical simulations show that the protocol is insensitive to the experimental imperfection, including systematic errors, random noise and decoherence. Therefore, the protocol is expected to expand the vision of realizing NPM. [ABSTRACT FROM AUTHOR]

Since the complexity nonlinearities generated by discontinuous control and event‐triggered scheme, fixed‐time formation in event‐based framework is a more challenging issue compared with the continuous‐time control. This paper focuses on fixed‐time leaderless formation problem for multi‐agent systems with undirected topology. We propose a distributed robust event‐triggered control strategy for the fixed‐time formation where predictor‐based state transformation is employed to deal with input delay and sliding mode technology is implemented to solve bounded disturbances. We also obtain that the upper bound of the formation settling time is only determined by delay time, control design parameters, network connectivity, and independent of the initial conditions. In addition, the lower bound for the interexecution time is calculated to ensure that there is no Zeno behavior occurs. Finally, some numerical simulations are presented to show the effectiveness of the strategies. [ABSTRACT FROM AUTHOR]

In this article, distributed tracking control is studied for multiple Euler–Lagrange systems in the presence of external disturbances and input saturation. Specifically, full‐state constraints, input saturation, communication delays, and unmeasured velocities are all considered simultaneously. First, a novel event‐triggered scheme is developed to save the communication source and reduce computational load. Second, the anti‐saturation compensation algorithm is exploited to compensate for system saturation. Third, an adaptive law is designed to offset external disturbances. Moreover, a high‐gain observer is employed to estimate unmeasured velocities. Theorem analysis shows the stability of the closed‐loop system, and numerical simulations are provided to verify the effectiveness of the proposed control strategy. [ABSTRACT FROM AUTHOR]

In this article, a novel robust finite‐time tracking control scheme is proposed for a class of uncertain nonlinear systems subject to the model uncertainty, external disturbance, and input saturation. A barrier function based disturbance observer (BFDO) with finite‐time convergence performance is developed to estimate the non‐smooth nonlinear compound disturbance, which includes the uncertainty, disturbance of system and input saturation. In addition, an adaptive continuous nonsingular terminal sliding mode controller, based on the barrier function and the estimate of the BFDO is developed. The Lyapunov stability and finite‐time convergence of the proposed control scheme are proved. The effectiveness and performance advantage of the proposed control scheme is demonstrated by numerical simulations and comparison with existing works. [ABSTRACT FROM AUTHOR]