This paper focuses on the application of H_∞preview control in automatic carrier landing system(ACLS)for carrier-based aircraft.Due to the mutual movement between aircraft and carrier,the landing process becomes cons...This paper focuses on the application of H_∞preview control in automatic carrier landing system(ACLS)for carrier-based aircraft.Due to the mutual movement between aircraft and carrier,the landing process becomes considerably more challenging compared to a conventional runway landing.ACLS systems mitigate this by predicting deck motion and generating ideal glide slope path for tracking.Although,this predicted glide slope information is available in advance,conventional control structures are still unable to use this future information.H_∞preview control has the ability to utilize this future information for improving tracking response and disturbance rejection.The process of incorporating preview information into ACLS framework and synthesizing the H_∞preview controller is presented.The methodology is verified using the example of F/A-18 automatic carrier landing problem and results are presented.展开更多
For carrier-based unmanned aerial vehicles(UAVs),one of the important problems is the design of an automatic carrier landing system(ACLS)that would enable the UAVs to accomplish autolanding on the aircraft carrier.How...For carrier-based unmanned aerial vehicles(UAVs),one of the important problems is the design of an automatic carrier landing system(ACLS)that would enable the UAVs to accomplish autolanding on the aircraft carrier.However,due to the movements of the flight deck with six degree-of-freedom,the autolanding becomes sophisticated.To solve this problem,an accurate and effective ACLS is developed,which is composed of an optimal preview control based flight control system and a Kalman filter based deck motion predictor.The preview control fuses the future information of the reference glide slope to improve landing precision.The reference glide slope is normally a straight line.However,the deck motion will change the position of the ideal landing point,and tracking the ideal straight glide slope may cause landing failure.Therefore,the predictive deck motion information from the deck motion predictor is used to correct the reference glide slope,which decreases the dispersion around the desired landing point.Finally,simulations are carried out to verify the performance of the designed ACLS based on a nonlinear UAV model.展开更多
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
An optimal preview method is applied to the design of terrain following controller for cruise missile. In this method, tracking errors and control increments are both considered in the quadratic cost function. Integra...An optimal preview method is applied to the design of terrain following controller for cruise missile. In this method, tracking errors and control increments are both considered in the quadratic cost function. Integrating the general optimal servo system with a preview feedforward compensation that feeds forward future command and future disturbance produces an optimal preview servo system. In the terrain following system, the flight altitude of the cruise missile is a command signal, and its future information can be known apriori. Hence, we have designed a terrain following controller with a basic state feedback and a feedforward compensation for future altitude information. Simulation results show that the performance of the terrain following system with such an optimal preview controller has been improved dramatically.展开更多
A valid preview control technique is presented for processing servo systemswith input delay based on extended error systems with input delay. The technique usesthe concept of error systems, establishes extended error ...A valid preview control technique is presented for processing servo systemswith input delay based on extended error systems with input delay. The technique usesthe concept of error systems, establishes extended error systems with input delay and de-rives preview control laws based on minimization of evaluation function. Finally, simula-tion is done on linear direct current motor without brush. The results reveal that the tech-nique proposed herein is valid for improving performance of servo systems.展开更多
The paper presents a preview controller design for ATS （active trailer steering） systems to improve high-speed stability of AHVs （articulated heavy vehicles）. An AHV consists of a towing unit, namely tractor or tr...The paper presents a preview controller design for ATS （active trailer steering） systems to improve high-speed stability of AHVs （articulated heavy vehicles）. An AHV consists of a towing unit, namely tractor or truck, and one or more towed units which called trailers. Individual units are connected to one another at articulated joints by mechanical couplings. Due to the multi-unit configurations, AHVs exhibit unique unstable motion modes, including jack-knifing, trailer swing and rollover. These unstable motion modes are the leading cause of highway accidents. To prevent these unstable motion modes, the preview controller, namely the LPDP （lateral position deviation preview） controller, is proposed. For a truck/full-trailer combination, the LPDP controller is designed to control the steering of the front and rear axle wheels of the trailing unit. The calculation of the corrective steering angle of the trailer front axle wheels is based on the preview information of the lateral position deviation of the trajectory of the axle center from that of the truck front axle center. Similarly, the steering angle of the trailer rear axle wheels is calculated by using the lateral position deviation of the trajectory of the axle center from that of the truck front axle. To perform closed-loop dynamic simulations and evaluate the vehicle performance measure, a driver model is introduced and it ＇derives＇ the AHV model based on well-defined testing specifications. The proposed preview control scheme in the continuous time domain is developed by using the LQR （linear quadratic regular） technique. The closed-loop simulation results indicate that the performance of the AHV with the LPDP controller is improved by decreasing rearward amplification ratio from the baseline value of 1.28 to 0.98 and reducing transient off-tracking by 95.03%. The proposed LPDP control algorithm provides an alternative method for the design optimization of AHVs with ATS systems.展开更多
A dual-rate preview control strategy for a type of discrete-time system is proposed based on the theory of multirate control. First, by using the discrete lifting technique, the general dual-rate discrete-time system ...A dual-rate preview control strategy for a type of discrete-time system is proposed based on the theory of multirate control. First, by using the discrete lifting technique, the general dual-rate discrete-time system is converted into a single-rate augmented system. On this basis, the augmented error system is constructed by introducing a first-order difference operator and the previewable reference signal. Then the tracking problem is transformed into a regulator problem of the augmented error system. The optimal preview control law of the augmented error system is obtained by using standard linear quadratic optimal preview control theory, and then the optimal preview controller of the original system is derived. In addition, the necessary and sufficient conditions for the controller are given.Finally, simulation results show the effectiveness of the proposed method.展开更多
An algorithm in which the optimal control law takes the advantage of the correlation between front and rear inputs, i.e., wheelbase preview information, for an active vehicle suspension design is described. Based on s...An algorithm in which the optimal control law takes the advantage of the correlation between front and rear inputs, i.e., wheelbase preview information, for an active vehicle suspension design is described. Based on simulations, the potential improvements from wheelbase preview and the effects of preview time are investigated.展开更多
Previous studies have confirmed in simulation and experiment that an improved control performance can be obtained when the optimal preview control method was applied to an active suspension system for a quarter car mo...Previous studies have confirmed in simulation and experiment that an improved control performance can be obtained when the optimal preview control method was applied to an active suspension system for a quarter car model. In order to investigate the effectiveness not only in riding comfort but also in road handling, an half car model with the hydro pneumatic active suspension system is proposed in this study. Whole preview control method and partial preview control method, in which the road information detected by the front wheel is sent to the controller to decide the input to rear suspension, are taken into design of the active suspension control system. Results of numerical simulation show that satisfactory control efficiency could be achieved in both whole preview control and partial preview control. The comparison of results suggests that whole preview control method can provide better system performance, but the partial preview control method is superior due to its lower cost.展开更多
In this paper,the optimal tracking control problem for discrete-time with state and input delays is studied based on the preview control method.First,a transformation is introduced.Thus,the system is transformed into ...In this paper,the optimal tracking control problem for discrete-time with state and input delays is studied based on the preview control method.First,a transformation is introduced.Thus,the system is transformed into a non-delayed system and the tracking problem of the time-delay system is transformed into the regulation problem of a non-delayed system via processing of the reference signal.Then,by applying the preview control theory,an augmented system for the non-delayed system is derived,and a controller with preview function is designed,assuming that the reference signal is previewable.Finally,the optimal control law of the augmented error system and the optimal control law of the original system are obtained by letting the preview length of the reference signal go to zero.Numerical simulations are provided to verify the presented results.展开更多
基金supported by the National Natural Science Foundation of China (Nos.61973158, 61304223, 61673209)the Aeronautical Science Foundation (NO.2016ZA52009)the Fundamental Research Funds for the Central Universities (Nos.NS2017015, NJ20170005)
文摘This paper focuses on the application of H_∞preview control in automatic carrier landing system(ACLS)for carrier-based aircraft.Due to the mutual movement between aircraft and carrier,the landing process becomes considerably more challenging compared to a conventional runway landing.ACLS systems mitigate this by predicting deck motion and generating ideal glide slope path for tracking.Although,this predicted glide slope information is available in advance,conventional control structures are still unable to use this future information.H_∞preview control has the ability to utilize this future information for improving tracking response and disturbance rejection.The process of incorporating preview information into ACLS framework and synthesizing the H_∞preview controller is presented.The methodology is verified using the example of F/A-18 automatic carrier landing problem and results are presented.
基金supported in part by the National Natural Science Foundations of China(Nos.61304223,61673209,61533008)the Aeronautical Science Foundation(No.2016ZA 52009)the Fundamental Research Funds for the Central Universities(No.NJ20160026)
文摘For carrier-based unmanned aerial vehicles(UAVs),one of the important problems is the design of an automatic carrier landing system(ACLS)that would enable the UAVs to accomplish autolanding on the aircraft carrier.However,due to the movements of the flight deck with six degree-of-freedom,the autolanding becomes sophisticated.To solve this problem,an accurate and effective ACLS is developed,which is composed of an optimal preview control based flight control system and a Kalman filter based deck motion predictor.The preview control fuses the future information of the reference glide slope to improve landing precision.The reference glide slope is normally a straight line.However,the deck motion will change the position of the ideal landing point,and tracking the ideal straight glide slope may cause landing failure.Therefore,the predictive deck motion information from the deck motion predictor is used to correct the reference glide slope,which decreases the dispersion around the desired landing point.Finally,simulations are carried out to verify the performance of the designed ACLS based on a nonlinear UAV model.
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.
文摘An optimal preview method is applied to the design of terrain following controller for cruise missile. In this method, tracking errors and control increments are both considered in the quadratic cost function. Integrating the general optimal servo system with a preview feedforward compensation that feeds forward future command and future disturbance produces an optimal preview servo system. In the terrain following system, the flight altitude of the cruise missile is a command signal, and its future information can be known apriori. Hence, we have designed a terrain following controller with a basic state feedback and a feedforward compensation for future altitude information. Simulation results show that the performance of the terrain following system with such an optimal preview controller has been improved dramatically.
文摘A valid preview control technique is presented for processing servo systemswith input delay based on extended error systems with input delay. The technique usesthe concept of error systems, establishes extended error systems with input delay and de-rives preview control laws based on minimization of evaluation function. Finally, simula-tion is done on linear direct current motor without brush. The results reveal that the tech-nique proposed herein is valid for improving performance of servo systems.
文摘The paper presents a preview controller design for ATS （active trailer steering） systems to improve high-speed stability of AHVs （articulated heavy vehicles）. An AHV consists of a towing unit, namely tractor or truck, and one or more towed units which called trailers. Individual units are connected to one another at articulated joints by mechanical couplings. Due to the multi-unit configurations, AHVs exhibit unique unstable motion modes, including jack-knifing, trailer swing and rollover. These unstable motion modes are the leading cause of highway accidents. To prevent these unstable motion modes, the preview controller, namely the LPDP （lateral position deviation preview） controller, is proposed. For a truck/full-trailer combination, the LPDP controller is designed to control the steering of the front and rear axle wheels of the trailing unit. The calculation of the corrective steering angle of the trailer front axle wheels is based on the preview information of the lateral position deviation of the trajectory of the axle center from that of the truck front axle center. Similarly, the steering angle of the trailer rear axle wheels is calculated by using the lateral position deviation of the trajectory of the axle center from that of the truck front axle. To perform closed-loop dynamic simulations and evaluate the vehicle performance measure, a driver model is introduced and it ＇derives＇ the AHV model based on well-defined testing specifications. The proposed preview control scheme in the continuous time domain is developed by using the LQR （linear quadratic regular） technique. The closed-loop simulation results indicate that the performance of the AHV with the LPDP controller is improved by decreasing rearward amplification ratio from the baseline value of 1.28 to 0.98 and reducing transient off-tracking by 95.03%. The proposed LPDP control algorithm provides an alternative method for the design optimization of AHVs with ATS systems.
基金Supported by National Natural Science Foundation of China （60574016）, the National Science Foundation for Distinguished Young Scholars of China （60825304）, and the Taishan Scholar Program of Shandong Province
基金Supported by the National Natural Science Foundation of China(61174209)
文摘A dual-rate preview control strategy for a type of discrete-time system is proposed based on the theory of multirate control. First, by using the discrete lifting technique, the general dual-rate discrete-time system is converted into a single-rate augmented system. On this basis, the augmented error system is constructed by introducing a first-order difference operator and the previewable reference signal. Then the tracking problem is transformed into a regulator problem of the augmented error system. The optimal preview control law of the augmented error system is obtained by using standard linear quadratic optimal preview control theory, and then the optimal preview controller of the original system is derived. In addition, the necessary and sufficient conditions for the controller are given.Finally, simulation results show the effectiveness of the proposed method.
文摘An algorithm in which the optimal control law takes the advantage of the correlation between front and rear inputs, i.e., wheelbase preview information, for an active vehicle suspension design is described. Based on simulations, the potential improvements from wheelbase preview and the effects of preview time are investigated.
文摘Previous studies have confirmed in simulation and experiment that an improved control performance can be obtained when the optimal preview control method was applied to an active suspension system for a quarter car model. In order to investigate the effectiveness not only in riding comfort but also in road handling, an half car model with the hydro pneumatic active suspension system is proposed in this study. Whole preview control method and partial preview control method, in which the road information detected by the front wheel is sent to the controller to decide the input to rear suspension, are taken into design of the active suspension control system. Results of numerical simulation show that satisfactory control efficiency could be achieved in both whole preview control and partial preview control. The comparison of results suggests that whole preview control method can provide better system performance, but the partial preview control method is superior due to its lower cost.
基金Supported by the National Natural Science Foundation of China(61174209).
文摘In this paper,the optimal tracking control problem for discrete-time with state and input delays is studied based on the preview control method.First,a transformation is introduced.Thus,the system is transformed into a non-delayed system and the tracking problem of the time-delay system is transformed into the regulation problem of a non-delayed system via processing of the reference signal.Then,by applying the preview control theory,an augmented system for the non-delayed system is derived,and a controller with preview function is designed,assuming that the reference signal is previewable.Finally,the optimal control law of the augmented error system and the optimal control law of the original system are obtained by letting the preview length of the reference signal go to zero.Numerical simulations are provided to verify the presented results.
