Practical Time-varying Formation Tracking Research Articles

Cooperative integrated practical time-varying formation tracking and control for multiple missiles system

Cooperative integrated practical time-varying formation tracking and control issues of multiple missiles system with multiple leader missiles and mismatched uncertainties are considered. The follower missiles' states are designed to track the convex combination of the leader missiles' ones while actualizing a predefined time-varying formation. Firstly, this paper establishes the integrated formation tracking and control models of multiple missiles system, where the outer-loop kinematic model and inner-loop dynamic model are considered simultaneously. Then, the integrated practical time-varying formation tracking and control protocol is presented, where the mismatched uncertainties and leader missiles' control input signals are estimated and compensated by employing the distributed extended state observers. Thirdly, an algorithm is presented to give the procedures for designing the protocol, in which the feasible formation tracking constrains are raised, and a series of linear matrix inequalities are solved for obtaining the control parameters. Sufficient conditions for actualizing the designed formation tracking are derived. Finally, a numerical simulation example reveals the effectiveness of the acquired results.

Practical time‐varying formation tracking for multiple non‐holonomic mobile robot systems based on the distributed extended state observers

Practical time-varying formation tracking analysis and design problems for multiple non-holonomic mobile robot systems with directed interaction topologies are investigated by using the distributed extended state observers, where the practical time-varying formation tracking error is controlled within an arbitrary small bound. Different from the previous work, the dynamics of each robot is non-holonomic and the followers are required to form the practical time-varying formation with respect to the leader of unknown control inputs. Besides, the disturbances and the uncertainties are considered in the dynamic model of the follower. Distributed extended state observers are constructed by using only the neighbouring relative information to estimate both the state and the unknown control inputs of the leader simultaneously. A practical time-varying formation tracking protocol is presented based on the distributed extended state observers. The gain matrices of the observers in the practical time-varying formation tracking protocol can be obtained by solving three linear matrix inequalities. Moreover, the stability of the multiple non-holonomic mobile robot system under the proposed protocol is proved by using the properties of the Laplacian matrix and the Lyapunov stability theory. Finally, two numerical simulation examples are given to illustrate the effectiveness of the obtained theoretical results.

Practical Time-Varying Formation Tracking for Second-Order Nonlinear Multiagent Systems With Multiple Leaders Using Adaptive Neural Networks.

Practical time-varying formation tracking problems for second-order nonlinear multiagent systems with multiple leaders are investigated using adaptive neural networks (NNs), where the time-varying formation tracking error caused by time-varying external disturbances can be arbitrarily small. Different from the previous work, there exists a predefined time-varying formation formed by the states of the followers and the formation tracks the convex combination of the states of the leaders with unknown control inputs. Besides, the dynamics of each agent has both matched/mismatched heterogeneous nonlinearities and disturbances simultaneously. First, a practical time-varying formation tracking protocol using adaptive NNs is proposed, which is constructed using only local neighboring information. The proposed control protocol can process not only the matched/mismatched heterogeneous nonlinearities and disturbances, but also the unknown control inputs of the leaders. Second, an algorithm with three steps is introduced to design the practical formation tracking protocol, where the parameters of the protocol are determined, and the practical time-varying formation tracking feasibility condition is given. Third, the stability of the closed-loop multiagent system is proven by using the Lyapunov theory. Finally, a simulation example is showed to illustrate the effectiveness of the obtained theoretical results.

Practical time-varying formation tracking for high-order nonlinear multi-agent systems based on the distributed extended state observer

ABSTRACTPractical time-varying formation tracking analysis and design problems for high-order nonlinear multi-agent systems are investigated, where the time-varying formation tracking error is controlled within an arbitrarily small bound. The states of followers form a predefined time-varying formation while tracking the state of the leader with unknown control input. Besides, the dynamics of each agent has heterogeneous nonlinearity and disturbance. First, a distributed extended state observer is constructed to estimate the follower's nonlinearity and disturbance, and the leader's unknown control input simultaneously. A protocol based on the distributed extended state observer is proposed. Second, sufficient conditions for the multi-agent systems to achieve the practical time-varying formation tracking under the protocol are presented by using the Lyapunov stability theory. Third, an approach is derived to design the proposed protocol by solving a linear matrix inequality. Finally, numerical simulation results are given to illustrate the effectiveness of the theoretical results.