The chattering characteristic of sliding mode control isanalyzed when it is applied in distributed control systems （DCSs）.For a DCS with random time delay and packet dropout, a discreteswitching system model with ti...The chattering characteristic of sliding mode control isanalyzed when it is applied in distributed control systems （DCSs）.For a DCS with random time delay and packet dropout, a discreteswitching system model with time varying sampling period isconstructed based on the time delay system method. The reachinglaw based sliding mode controller is applied in the proposedsystem. The exponential stability condition in the form of linearmatrix inequality is figured out based on the multi-Lyaponov functionmethod. Then, the chattering characteristic is analyzed for theswitching system, and a chattering region related with time varyingsampling period and external disturbance is proposed. Finally, numericalexamples are given to illustrate the validity of the analysisresult.展开更多
Rotor and ducted-fan structured unmanned helicopters have shown energy efficiency in low flight speed and hovering, due to the novel ducted-fan structure. However, its aerodynamic characteristics may change dramatical...Rotor and ducted-fan structured unmanned helicopters have shown energy efficiency in low flight speed and hovering, due to the novel ducted-fan structure. However, its aerodynamic characteristics may change dramatically when flight at higher speed,resulting in a wide flight envelope when compared with conventional structured helicopters. Hence, the flight controller is required to schedule itself based on the flight states and guarantees the overall performances of the helicopter on the entire flight envelop. This paper presents a switching system theory based approach to design the optimal controllers over a wide region of flight envelop. In the proposed method, a family of robust controller are designed based on typical operational conditions and the controller is adjusted to guarantee the stability when the switching event is trigged. A hysteresis switching logic is utilized to ensure smooth transient between specific operational subspaces. The stability of the proposed control method was analyzed through Lyapunov theory. Nonlinear simulations based flight dynamics of the prototype helicopter have demonstrated the flexibility and efficiency of the proposed work.展开更多
基金supported by the National Natural Science Fundation of China(5147618751506221)+1 种基金the Natural Science Basic Research Plan in Shaanxi Province of China(2015JQ51792015JM5207)
文摘The chattering characteristic of sliding mode control isanalyzed when it is applied in distributed control systems （DCSs）.For a DCS with random time delay and packet dropout, a discreteswitching system model with time varying sampling period isconstructed based on the time delay system method. The reachinglaw based sliding mode controller is applied in the proposedsystem. The exponential stability condition in the form of linearmatrix inequality is figured out based on the multi-Lyaponov functionmethod. Then, the chattering characteristic is analyzed for theswitching system, and a chattering region related with time varyingsampling period and external disturbance is proposed. Finally, numericalexamples are given to illustrate the validity of the analysisresult.
基金supported by Aeronautical Science Foundation of China(Grant No.20150752011)the Young Elite Scientists Sponsorship Program by China Association for Science and Technology(Grant No.2016QNRC001)
文摘Rotor and ducted-fan structured unmanned helicopters have shown energy efficiency in low flight speed and hovering, due to the novel ducted-fan structure. However, its aerodynamic characteristics may change dramatically when flight at higher speed,resulting in a wide flight envelope when compared with conventional structured helicopters. Hence, the flight controller is required to schedule itself based on the flight states and guarantees the overall performances of the helicopter on the entire flight envelop. This paper presents a switching system theory based approach to design the optimal controllers over a wide region of flight envelop. In the proposed method, a family of robust controller are designed based on typical operational conditions and the controller is adjusted to guarantee the stability when the switching event is trigged. A hysteresis switching logic is utilized to ensure smooth transient between specific operational subspaces. The stability of the proposed control method was analyzed through Lyapunov theory. Nonlinear simulations based flight dynamics of the prototype helicopter have demonstrated the flexibility and efficiency of the proposed work.
