Hovering control for quadrotor aircraft based on finite-time control algorithm

Finite-time control systems usually have better disturbance rejection property and faster convergence performance. For the linearized dynamics of the linear navigation system of an agricultural tractor, a novel control algorithm based on finite-time control technique and saturation method is proposed. Based upon the presented method, the finite-time saturated controller is designed for the linear navigation of an agricultural tractor, and the global stability for the closed loop system is proved. Meanwhile, the selection of parameters in saturated controller just requires some simple mathematical relationships, and the control method has some potential practical applications. Simulation results also verify the effectiveness of the proposed method.

In this paper, the distributed finite-time containment control problem for double-integrator multiagent systems with multiple leaders and external disturbances is discussed. In the presence of multiple dynamic leaders, by utilizing the homogeneous control technique, a distributed finite-time observer is developed for the followers to estimate the weighted average of the leaders' velocities at first. Then, based on the estimates and the generalized adding a power integrator approach, distributed finite-time containment control algorithms are designed to guarantee that the states of the followers converge to the dynamic convex hull spanned by those of the leaders in finite time. Moreover, as a special case of multiple dynamic leaders with zero velocities, the proposed containment control algorithms also work for the case of multiple stationary leaders without using the distributed observer. Simulations demonstrate the effectiveness of the proposed control algorithms.

This paper focuses on finite-time control in the attitude control system of the spacecraft based on the rotation matrix by using homogeneous method. Because the rotation matrix represents the set of attitudes both globally and uniquely, the system can overcome the drawback of unwinding which results in extra fuel consumption. In order to deal with actuator saturations, a finite-time controller is investigated by using the saturation function. Then, based on a novel filter, a finite-time output feedback controller with actuator saturations is designed. Theoretical analysis shows that the proposed controllers can make the attitude error converges to zero in finite time. Numerical simulations also demonstrate that the proposed control schemes are effective.

A finite-time control strategy is proposed to solve the problem of position tracking control for a permanent magnet synchronous motor servo system. It can guarantee that the motor’s desired position can be tracked in a finite time. Firstly, for the d-axis voltage, a first-order finite-time controller is designed based on the vector control principle. Then, for the q-axis voltage, based on a radial basis function (RBF) neural network, an integral high-order terminal sliding mode controller is designed. Theoretical analysis shows that under the proposed controller, the desired position can be tracked by the motor position in a finite time. Simulation results are given to show that the proposed control method has a strong anti-disturbance ability and a fast convergence performance.

The problem of finite-time attitude synchronisation and tracking for a group of rigid spacecraft nonlinear dynamics is investigated in this paper. First of all, in the presence of environmental disturbance, a novel decentralised control law is proposed to ensure that the spacecraft attitude error dynamics can converge to the sliding surface in finite time; then the final practical finite-time stability of the attitude error dynamics can be guaranteed in small regions. Furthermore, a modified finite-time control law is proposed to address the control chattering. The control law can guarantee a group of spacecraft to attain desired time-varying attitude and angular velocity while maintaining attitude synchronisation with other spacecraft in the formation. Simulation examples are provided to illustrate the feasibility of the control algorithm presented in this paper.

This paper considers the problem of finite-time synchronization for a class of second-order nonlinear multi-agent systems with a leader-follower architecture. By using the finite-time control technique and homogenous systems theory, a finite-time state feedback controller is first proposed. Then to address the lack of velocity measurement, a finite-time convergent observer is constructed to estimate the unknown velocity information in a finite time. Finally, an observer-based finite-time output feedback controller is developed. Rigorous proof shows that the systems output can reach synchronization in a finite time and the final consensus states are the leader's states. In addition, for some special second-order multi-agent systems, a bounded finite-time output feedback controller can also be designed.

This paper investigates the finite-time formation control problem for high-order nonlinear multiagent systems (MASs) with the consideration of obstacle avoidance, unmeasurable states and dead-zone input. A neural networks k-filter observer is designed to estimate the unmeasurable states and cope with the problem of dead-zone input. Also, by using an integral-multiplicative tangent Lyapunov-barrier function (LBF), the obstacle avoidance mission can be completed for MASs without dynamic mismatching. Then, combining the finite-time method and the backstepping theory, an output-feedback finite-time controller is designed for high-order nonlinear MASs. Theoretical analysis indicates that the control algorithm can not only make agents accomplish the formation obstacle avoidance task but also guarantee the boundedness of signals in the system. A simulation demonstrates the effectiveness of the proposed control algorithm. Note to Practitioners—This article studies the formation obstacle avoidance problem for MASs which plays an important role in transportation, exploration and rescue activities. Unmeasurable states and dead-zone input, which often occur in practice, are also considered and handled by a neural networks k-filter observer. An integral-multiplicative tangent LBF is utilized to complete the obstacle avoid task which is necessary for actual systems. Moreover, to be more feasible in industrial applications, the finite-time control strategy is used in the controller design.

A robust finite time sliding mode control strategy is proposed in this paper for a flexible air-breathing hypersonic vehicle (FAHV) model with aerodynamic parameter uncertainty. The strong coupling among the aerodynamics, the propulsion system and the flexibility effects makes the problem more challenging. Firstly, to reduce the complexity of the controller design, the FAHV model is transformed into three subsystems (velocity subsystem, altitude and flight path angle subsystem, attack of angle and pitch rate subsystem). Secondly, based on super-twisting algorithm, a novel finite time disturbance observer and an improved sliding mode controller are designed to ensure the finite time stability of each subsystem. The proposed disturbance observer can estimate the uncertainty and the derivative of virtual control in finite time. Finally, simulation results are presented to show the precision and rapidness in tracking the reference trajectory and validate the effectiveness of the designed controller.

Event-triggered finite-time formation control is considered for second-order leader-following multi-agent systems with nonlinear term time delay in this study. Collision avoidance radius is designed for a class of second-order nonlinear multiagent systems to avoid collisions between agents. Collision avoidance control is realised by detecting the flight radius. Control cost is economised, and communication volume is reduced by controlling key nodes and designing an event-triggered control strategy. The system can realise formation control in finite time by designing an FTC function. Some sufficient conditions for the formation of the second-order multi-agent system in finite time are obtained by using Lyapunov stability theory and analysis. The integral sliding mode control algorithm and finite-time stability theory are used to enhance the robustness of the system, and the upper bound of finite time is given. At the same time, the ability of the designed event-triggered function to avoid Zeno behaviour is proven. Finally, the feasibility of the results is verified through a numerical simulation.

Finite-time output feedback attitude control for rigid spacecraft under control input saturation

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Distributed containment control for multiple ocean bottom flying nodes with velocity error constraint and input saturation

Finite-time blended control for air-to-air missile with lateral thrusters and aerodynamic surfaces