Carrier-based aircraft carrier landing is a special kind of tracking control problem and not suitable for classical control methods,which may miss the desired performance or result in overdesign.Therefore,we present a...Carrier-based aircraft carrier landing is a special kind of tracking control problem and not suitable for classical control methods,which may miss the desired performance or result in overdesign.Therefore,we present an optimal preview control for automatic carrier landing system(ACLS)by using state information of system,as well as future reference information,which can avoid the shortcomings of classical control methods.Since the flight performance of carrier-based aircraft is disturbed by air wake when the aircraft flies near the area of carrier stern,we design a disturbance rejection strategy to ensure that aircraft track the glide path with high precision and robustness.Further,carrier-based aircraft is a complex nonlinear system.However,the nonlinear model of carrier-based aircraft can be linearized at equilibrium landing state and decoupled into the longitudinal model and the lateral model.Therefore,an optimal preview control system is designed.The simulation results of a carrier-based aircraft show that the optimal preview control system can effectively suppress air wake.Tracking accuracy of optimal preview controller is higher than that of the proportional integral differential(PID)control system.展开更多
In order to investigate the injection current uniformity around the induction cell bores, two fully electromagnetic （EM） models are respectively established for a single-stage induction cell and an induction voltage...In order to investigate the injection current uniformity around the induction cell bores, two fully electromagnetic （EM） models are respectively established for a single-stage induction cell and an induction voltage adder （IVA） with three cells stacked in series, without considering electron emission. By means of these two models, some factors affecting the injection current uni- formity are simulated and analyzed, such as the impedances of adders and loads, cell locations, and feed timing of parallel driving pulses. Simulation results indicate that higher impedances of adder and loads are slightly beneficial to improve injection current uniformity. As the impedances of adder and loads increase from 5 Ω to 30Ω, the asymmetric coefficient of feed currents decreases from 10.3% to 6.6%. The current non-uniformity within the first cell is a little worse than that in other downstream cells. Simulation results also show that the feed timing would greatly affect current waveforms, and consequently cause some distortion in pulse fronts of cell output voltages. For a given driving pulse with duration time of 70-80 ns, the feed timing with a time deviation of less than 20 ns is acceptable for the three-cell IVAs, just causing the rise time of output voltages to increase about 5 ns at most and making the peak voltage decrease by 3.5%.展开更多
This paper proposes a static-output-feedback based robust fuzzy wheelbase preview control algorithm for uncertain active suspensions with time delay and finite frequency constraint.Firstly,a Takagi-Sugeno(T-S)fuzzy au...This paper proposes a static-output-feedback based robust fuzzy wheelbase preview control algorithm for uncertain active suspensions with time delay and finite frequency constraint.Firstly,a Takagi-Sugeno(T-S)fuzzy augmented model is established to formulate the half-car active suspension system with consideration of time delay,sprung mass variation and wheelbase preview information.Secondly,in view of the resonation between human’s organs and vertical vibrations in the frequency range of 4–8 Hz,a finite frequency control criterion in terms of H∞norm is developed to improve ride comfort.Meanwhile,other mechanical constraints are also considered and satisfied via generalized H2 norm.Thirdly,in order to maintain the feasibility of the controller despite of some state variables are not online-measured,a two stage approach is adopted to derive a static output feedback controller.Finally,numerical simulation results illustrate the excellent performance of the proposed controller.展开更多
针对自主车辆换道轨迹跟踪精度较低等问题进行了研究。提出了基于轨迹预测的多点预瞄权重增益分配的方法。首先,根据车辆与路径的实时横向偏差以及航向角偏差,建立驾驶员转向模型,获得最优方向盘转角;其次,为了提高车辆换道路径跟踪时...针对自主车辆换道轨迹跟踪精度较低等问题进行了研究。提出了基于轨迹预测的多点预瞄权重增益分配的方法。首先,根据车辆与路径的实时横向偏差以及航向角偏差,建立驾驶员转向模型,获得最优方向盘转角;其次,为了提高车辆换道路径跟踪时的稳定性,采用线性模型预测控制(linear model predictive control,L-MPC)策略设计轨迹跟踪控制器。最后,搭建Carsim&Simulink联合仿真模型,针对不同车速设置对比实验进行分析,结果表明基于轨迹预测的驾驶员模型能较好地跟踪换道轨迹,且稳态行驶下的路径跟踪最大横向误差为8.1%,但在高速极限工况时路径跟踪适应性较差,而L-MPC策略在高速时具有更好的路径跟踪精度及稳定性,其跟踪误差小于4%。展开更多
基金supported in part by the National Natural Science Foundation of China(Nos.61741313,61304223,61673209,61533008)the Jiangsu Six Peak of Talents program(No.KTHY-027)+1 种基金the Aeronautical Science Foundation(No.2016ZA 52009)the Fundamental Research Funds for the Central Universities(Nos.NJ20160026,NS2017015)
文摘Carrier-based aircraft carrier landing is a special kind of tracking control problem and not suitable for classical control methods,which may miss the desired performance or result in overdesign.Therefore,we present an optimal preview control for automatic carrier landing system(ACLS)by using state information of system,as well as future reference information,which can avoid the shortcomings of classical control methods.Since the flight performance of carrier-based aircraft is disturbed by air wake when the aircraft flies near the area of carrier stern,we design a disturbance rejection strategy to ensure that aircraft track the glide path with high precision and robustness.Further,carrier-based aircraft is a complex nonlinear system.However,the nonlinear model of carrier-based aircraft can be linearized at equilibrium landing state and decoupled into the longitudinal model and the lateral model.Therefore,an optimal preview control system is designed.The simulation results of a carrier-based aircraft show that the optimal preview control system can effectively suppress air wake.Tracking accuracy of optimal preview controller is higher than that of the proportional integral differential(PID)control system.
基金supported by National Natural Science Foundation of China(No.51307141)partly by the State Key Laboratory of Intense Pulsed Radiation Simulation(Northwest Institute of Nuclear Technology)under Contract SKLIPR 1206
文摘In order to investigate the injection current uniformity around the induction cell bores, two fully electromagnetic （EM） models are respectively established for a single-stage induction cell and an induction voltage adder （IVA） with three cells stacked in series, without considering electron emission. By means of these two models, some factors affecting the injection current uni- formity are simulated and analyzed, such as the impedances of adders and loads, cell locations, and feed timing of parallel driving pulses. Simulation results indicate that higher impedances of adder and loads are slightly beneficial to improve injection current uniformity. As the impedances of adder and loads increase from 5 Ω to 30Ω, the asymmetric coefficient of feed currents decreases from 10.3% to 6.6%. The current non-uniformity within the first cell is a little worse than that in other downstream cells. Simulation results also show that the feed timing would greatly affect current waveforms, and consequently cause some distortion in pulse fronts of cell output voltages. For a given driving pulse with duration time of 70-80 ns, the feed timing with a time deviation of less than 20 ns is acceptable for the three-cell IVAs, just causing the rise time of output voltages to increase about 5 ns at most and making the peak voltage decrease by 3.5%.
基金supported by the National Natural Science Foundation of China(51705084)the Natural Science Foundation of Guangdong Province(2018A030313999,2019A1515011602)+6 种基金the Fundamental Research Funds for the Central Universities(N2003032)the Opening Project of Guangdong Provincial Key Laboratory of Technique and Equipment for Macromolecular Advanced ManufacturingSouth China University of Technology(2019kfkt06,2020kfkt05)the Research Grants of the University of Macao(MYRG2019-00028-FST)Guangdong Regular Institutions of Characteristic Innovation Project(2017KTSCX176)Key Laboratory of Robotics and Intelligent Equipment of Guangdong Regular Institutions of Higher Education(2017KSYS009)the National Key Research and Development Program of China(2017YFB1300200,2017YFB1300203)。
文摘This paper proposes a static-output-feedback based robust fuzzy wheelbase preview control algorithm for uncertain active suspensions with time delay and finite frequency constraint.Firstly,a Takagi-Sugeno(T-S)fuzzy augmented model is established to formulate the half-car active suspension system with consideration of time delay,sprung mass variation and wheelbase preview information.Secondly,in view of the resonation between human’s organs and vertical vibrations in the frequency range of 4–8 Hz,a finite frequency control criterion in terms of H∞norm is developed to improve ride comfort.Meanwhile,other mechanical constraints are also considered and satisfied via generalized H2 norm.Thirdly,in order to maintain the feasibility of the controller despite of some state variables are not online-measured,a two stage approach is adopted to derive a static output feedback controller.Finally,numerical simulation results illustrate the excellent performance of the proposed controller.
文摘针对自主车辆换道轨迹跟踪精度较低等问题进行了研究。提出了基于轨迹预测的多点预瞄权重增益分配的方法。首先,根据车辆与路径的实时横向偏差以及航向角偏差,建立驾驶员转向模型,获得最优方向盘转角;其次,为了提高车辆换道路径跟踪时的稳定性,采用线性模型预测控制(linear model predictive control,L-MPC)策略设计轨迹跟踪控制器。最后,搭建Carsim&Simulink联合仿真模型,针对不同车速设置对比实验进行分析,结果表明基于轨迹预测的驾驶员模型能较好地跟踪换道轨迹,且稳态行驶下的路径跟踪最大横向误差为8.1%,但在高速极限工况时路径跟踪适应性较差,而L-MPC策略在高速时具有更好的路径跟踪精度及稳定性,其跟踪误差小于4%。
基金supported by the National Natural Science Foundation of China(No.51876089)the Postgraduate Research&Practice Innovation Program of Nanjing University of Aeronautics and Astronautics(No.xcxjh20210204)the Open Foundation of the State Key Laboratory of Fluid Power and Mechatronic Systems(No.GZKF-202005)。
