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In this paper, a robust control strategy is developed for unmanned helicopter prototype to simultaneously deal with random wind disturbances and remote communication delays. First, in the helicopter system modeling, the wind gust is not only treated as bounded external load disturbance, but propeller force-thrust coefficient variation that is caused by wind disturbance is also considered. Then, by equivalently treating the remote communication delays as random input delays, a robust attitude controller with energy-to-energy performance is developed for the helicopter system. Lyapunov-Krasovskii functions are utilized to analyze the stability of the proposed robust attitude controller. The gains of controller are calculated by solving linear matrix inequalities. Finally, by selecting Quanser’s three degrees of freedom(3-DOF) helicopter prototype as the test bench, three groups of comparative tests are carried out respectively, in which electric fan is utilized to generate external wind gusts while random delays are added to the feedback loop. Compared with conventional H-infinity controller, the effectiveness as well as superiority of proposed control approach is well verified.

This paper proposed a robust attitude controller design for unmanned helicopter under remote communication delays. Based on dynamical model of helicopter system, Lyapunov-Krasovskii theory is utilized in the stability analysis of proposed attitude controller design. Energy-to-energy strategy is used to ensure the robust performance of proposed controller against remote communication delays as well as payload disturbances. And the controller gains are obtained by solving a set of linear matrix inequalities (LMI). Based on Quanser's laboratory 3-DOF helicopter platform, both simulation and experimental tests are carried out to show the effectiveness and performance of proposed robust attitude controller. Compared with conventional sliding mode controller, the superiority of proposed controller is demonstrated.

With the consistent tendency of electrification and intelligentization of marine systems in recent years, the electric propulsion system has been a prospective candidate for ships due to its potential in energy saving, environmental protection, high efficiency, and high reliability. However, time-varying delays of communication networks would be induced due to increasing information exchange requirement that caused by the increasing number of devices connecting to the communication networks as well as bandwidth limitation of marine network. Meanwhile, the propeller load is difficult to model due to the complexity of ship dynamics, which increases the uncertainty of marine electric propulsion system. Thus, robust control of the marine electric propulsion system is necessary and challenging. This paper presents a mixed H ∞ ∕ L Q R robust controller design for marine electric propulsion system to address robust speed tracking problem under possible network-induced delays. The propeller dynamic model is built via open-water experimental data to reflect propeller load characteristics. Then, a delay-free model is established for the marine electric propulsion system by using system augmentation technique, with the random network-induced delay characterized by polytopic inclusions and Taylor series expansion. A mixed H ∞ ∕ L Q R robust controller design is proposed for the marine electric propulsion system. Finally, based on a detailed controller area network model, the performance and effectiveness of the mixed H ∞ ∕ L Q R robust controller are demonstrated by comparative simulation tests of a marine electric propulsion system with 4.088 MW permanent magnet synchronous motor (PMSM).