This article investigates a class of finite-time cooperative tracking problems of heterogeneous mixed-order multiagent systems (MASs) with higher-order dynamics. Different from the previous works of heterogeneous MASs, the agents in this study are considered to have different first-, second-, or even higher-order nonlinear dynamics. It means that, according to different tasks and situations, the following agents can have nonidentical orders or different numbers of states to be synchronized, which is more general for the practical cooperative applications. The leader is a higher-order nonautonomous system and contains full state information to be synchronized for all agents with mixed-order dynamics. Accordingly, the spanning tree is defined based on the specific state rather than on the agent to guarantee that each following agent can receive adequate state information. Distributed control protocols are designed for all agents to achieve the ultimate state synchronization to the leader in finite time. The Lyapunov approach is used for the stability analysis and a practical example of mixed-order mechanical MASs verifies the effectiveness and performance of the proposed distributed control protocols.

In this article, the event-triggered observation-based tracking control issue of nonlinear mixed-order multiagent systems (MASs) under the actuator saturation is investigated. The studied mixed-order MASs include heterogeneous agents which have nonidentical orders of dynamics and different quantities and types of states to be synchronized. To relieve the communication load and decrease the tear and wear due to the frequent regulation of actuators, a distributed cooperative tracking control strategy utilizing the event-triggered mechanism is proposed to realize the final synchronization for all nonlinear mixed-order followers. In addition, the distributed disturbance observer is developed for the heterogeneous followers to lower the impact of unknown dynamics and external disturbances. And, the actuator saturation problem is considered to ensure the wider applicability of the presented control strategy in actual applications. The stability of the controlled mixed-order MASs is proved by Lyapunov theory for ensuring the synchronization of all states under the proposed event-triggered observation-based cooperative control strategy. Finally, the example of unmanned aerial vehicle is utilized to verify the effectiveness of the consensus cooperative control strategy.