A model reference adaptive control(MRAC)with smooth switching scheme was proposed for piecewise linear systems,and the method was utilized in turbofan engine control to avoid the discontinuity of control input.In this...A model reference adaptive control(MRAC)with smooth switching scheme was proposed for piecewise linear systems,and the method was utilized in turbofan engine control to avoid the discontinuity of control input.In this scheme,each sub-region of the operating envelope had its own MRAC controller,and smooth indicator function based smooth switching scheme was introduced to switch multiple controllers smoothly at the boundary of adjacent sub-regions.The Lyapunov stability analysis indicated that the proposed smooth switching scheme can guarantee the convergence of the closed-loop system during the controllers switching.The tracking error system was converted into a switched system to analyze the global stability of the closed-loop system.The advantage of the method was that the chattering of system output and instability caused by asynchronous switching can be eliminated.The simulation illustrates the effectiveness of the proposed control scheme in comparison with the existing MRAC controller with gain scheduling for turbofan engine.展开更多
The experimental studies and numerical simulation were conducted on the effects of the dome fuel distribution ratio on the lean blowout of a model combustor.The experimental results indicate that as the key parameter,...The experimental studies and numerical simulation were conducted on the effects of the dome fuel distribution ratio on the lean blowout of a model combustor.The experimental results indicate that as the key parameter,the dome fuel distribution ratio,increases from 2.06%to 16.67%,the lean blowout equivalence ratio declines obviously at the beginning,and then the decrease slows down,in addition,the amplitude of the pressure fluctuation in the combustor reduces significantly while the dominant frequency keeps basically constant.In order to analyze the experimental results,the numerical simulation is adopted.The temperature and local equivalence ratio distributions are employed to explain the reason why the lean blowout performance improves with the increase of the dome fuel distribution ratio.展开更多
文摘A model reference adaptive control(MRAC)with smooth switching scheme was proposed for piecewise linear systems,and the method was utilized in turbofan engine control to avoid the discontinuity of control input.In this scheme,each sub-region of the operating envelope had its own MRAC controller,and smooth indicator function based smooth switching scheme was introduced to switch multiple controllers smoothly at the boundary of adjacent sub-regions.The Lyapunov stability analysis indicated that the proposed smooth switching scheme can guarantee the convergence of the closed-loop system during the controllers switching.The tracking error system was converted into a switched system to analyze the global stability of the closed-loop system.The advantage of the method was that the chattering of system output and instability caused by asynchronous switching can be eliminated.The simulation illustrates the effectiveness of the proposed control scheme in comparison with the existing MRAC controller with gain scheduling for turbofan engine.
基金the support of the National Natural Science Foundation of China (No. 50876104 and 51676182)
文摘The experimental studies and numerical simulation were conducted on the effects of the dome fuel distribution ratio on the lean blowout of a model combustor.The experimental results indicate that as the key parameter,the dome fuel distribution ratio,increases from 2.06%to 16.67%,the lean blowout equivalence ratio declines obviously at the beginning,and then the decrease slows down,in addition,the amplitude of the pressure fluctuation in the combustor reduces significantly while the dominant frequency keeps basically constant.In order to analyze the experimental results,the numerical simulation is adopted.The temperature and local equivalence ratio distributions are employed to explain the reason why the lean blowout performance improves with the increase of the dome fuel distribution ratio.
