Projective synchronization problems of a drive system and a particular response network were investigated,where the drive system is an arbitrary system with n+1 dimensions;it may be a linear or nonlinear system,and ev...Projective synchronization problems of a drive system and a particular response network were investigated,where the drive system is an arbitrary system with n+1 dimensions;it may be a linear or nonlinear system,and even a chaotic or hyperchaotic system,the response network is complex system coupled by N nodes,and every node is showed by the approximately linear part of the drive system.Only controlling any one node of the response network by designed controller can achieve the projective synchronization.Some numerical examples were employed to verify the effectiveness and correctness of the designed controller.展开更多
为了提高控制器局域网络(controller area network,CAN)通信的实时性,文章基于时间触发CAN(time-triggered CAN,TTCAN)协议,采用verilog硬件描述语言设计实现TTCAN总线控制器。该控制器可在经典CAN模式与TTCAN模式之间进行切换,同时兼...为了提高控制器局域网络(controller area network,CAN)通信的实时性,文章基于时间触发CAN(time-triggered CAN,TTCAN)协议,采用verilog硬件描述语言设计实现TTCAN总线控制器。该控制器可在经典CAN模式与TTCAN模式之间进行切换,同时兼容可变速率CAN(CAN with flexible data rate,CAN FD)协议下的高速通信。实验结果证明,相较于经典CAN总线控制器,该TTCAN总线控制器能够减少在高总线负载率下周期性报文的发送延时,在全波特率范围内且总线负载率大于等于60%的情况下,能够减少75%以上的CAN报文发送延时。展开更多
森林火灾初期控制尤为重要,目前我国小型的四驱森林消防车的电气控制系统多由传统的电气元件组合而成,存有布线安装复杂、故障率高、操作步骤多等问题。控制器局域网(Controller Area Network,CAN)总线+PLC控制技术具有良好的人机操作...森林火灾初期控制尤为重要,目前我国小型的四驱森林消防车的电气控制系统多由传统的电气元件组合而成,存有布线安装复杂、故障率高、操作步骤多等问题。控制器局域网(Controller Area Network,CAN)总线+PLC控制技术具有良好的人机操作界面、一键式控制功能和安全保护等功能操作简便,以皮卡森林消防车为研究对象,研究了CAN总线技术在皮卡森林消防车上的集成技术应用、软件研发和结合方法,并进行实践测验。结果得出,CAN总线技术可以在该类型消防车上进行安装和使用,不仅促进了皮卡消防车通信系统的先进性和灵活性,同时提高了操作的便捷性、控制的稳定性和准确性,还大幅度提升森林水罐消防车系统的性能及操作性;对拓展森林消防车以及在其他特种车辆的控制系统和功能性具有重要作用和意义。展开更多
A wireless body area network offers cost-effective solutions for healthcare infrastructure. An adaptive transmission algorithm is designed to handle channel efficiency, which adjusts packet size according to the diffe...A wireless body area network offers cost-effective solutions for healthcare infrastructure. An adaptive transmission algorithm is designed to handle channel efficiency, which adjusts packet size according to the difference in feature-point values that indicate biomedical signal characteristics. Furthermore, we propose a priority-adjustment method that enhances quality of service while guaranteeing signal integrity. A large number of simulations were carried out for performance evaluation. We use electrocardiogram and electromyogram signals as reference biomedical signals for performance verification. From the simulation results, we find that the average packet latency of proposed scheme is enhanced by 30% compared to conventional method. The simulation results also demonstrate that the proposed algorithm achieves significant performance improvement in terms of drop rates of high-priority packets around 0.3%-0.9 %.展开更多
A wireless body area network (WBAN) allows integration of low power, invasive or noninvasive miniaturized sensors around a human body. WBAN is expected to become a basic infrastructure element for human health monitor...A wireless body area network (WBAN) allows integration of low power, invasive or noninvasive miniaturized sensors around a human body. WBAN is expected to become a basic infrastructure element for human health monitoring. The Task Group 6 of IEEE 802.15 is formed to address specific needs of body area network. It defines a medium access control layer that supports various physical layers. In this work, we analyze the efficiency of simple slotted ALOHA scheme, and then propose a novel allocation scheme that controls the random access period and packet transmission probability to optimize channel efficiency. NS-2 simulations have been carried out to evaluate its performance. The simulation results demonstrate significant performance improvement in latency and throughput using the proposed MAC algorithm.展开更多
This paper investigates interception missiles’trajectory tracking guidance problem under wind field and external disturbances in the boost phase.Indeed,the velocity control in such trajectory tracking guidance system...This paper investigates interception missiles’trajectory tracking guidance problem under wind field and external disturbances in the boost phase.Indeed,the velocity control in such trajectory tracking guidance systems of missiles is challenging.As our contribution,the velocity control channel is designed to deal with the intractable velocity problem and improve tracking accuracy.The global prescribed performance function,which guarantees the tracking error within the set range and the global convergence of the tracking guidance system,is first proposed based on the traditional PPF.Then,a tracking guidance strategy is derived using the integral sliding mode control techniques to make the sliding manifold and tracking errors converge to zero and avoid singularities.Meanwhile,an improved switching control law is introduced into the designed tracking guidance algorithm to deal with the chattering problem.A back propagation neural network(BPNN)extended state observer(BPNNESO)is employed in the inner loop to identify disturbances.The obtained results indicate that the proposed tracking guidance approach achieves the trajectory tracking guidance objective without and with disturbances and outperforms the existing tracking guidance schemes with the lowest tracking errors,convergence times,and overshoots.展开更多
In this paper,an intelligent control method applying on numerical virtual flight is proposed.The proposed algorithm is verified and evaluated by combining with the case of the basic finner projectile model and shows a...In this paper,an intelligent control method applying on numerical virtual flight is proposed.The proposed algorithm is verified and evaluated by combining with the case of the basic finner projectile model and shows a good application prospect.Firstly,a numerical virtual flight simulation model based on overlapping dynamic mesh technology is constructed.In order to verify the accuracy of the dynamic grid technology and the calculation of unsteady flow,a numerical simulation of the basic finner projectile without control is carried out.The simulation results are in good agreement with the experiment data which shows that the algorithm used in this paper can also be used in the design and evaluation of the intelligent controller in the numerical virtual flight simulation.Secondly,combined with the real-time control requirements of aerodynamic,attitude and displacement parameters of the projectile during the flight process,the numerical simulations of the basic finner projectile’s pitch channel are carried out under the traditional PID(Proportional-Integral-Derivative)control strategy and the intelligent PID control strategy respectively.The intelligent PID controller based on BP(Back Propagation)neural network can realize online learning and self-optimization of control parameters according to the acquired real-time flight parameters.Compared with the traditional PID controller,the concerned control variable overshoot,rise time,transition time and steady state error and other performance indicators have been greatly improved,and the higher the learning efficiency or the inertia coefficient,the faster the system,the larger the overshoot,and the smaller the stability error.The intelligent control method applying on numerical virtual flight is capable of solving the complicated unsteady motion and flow with the intelligent PID control strategy and has a strong promotion to engineering application.展开更多
In this paper, a filtering method is presented to estimate time-varying parameters of a missile dual control system with tail fins and reaction jets as control variables. In this method, the long-short-term memory(LST...In this paper, a filtering method is presented to estimate time-varying parameters of a missile dual control system with tail fins and reaction jets as control variables. In this method, the long-short-term memory(LSTM) neural network is nested into the extended Kalman filter(EKF) to modify the Kalman gain such that the filtering performance is improved in the presence of large model uncertainties. To avoid the unstable network output caused by the abrupt changes of system states,an adaptive correction factor is introduced to correct the network output online. In the process of training the network, a multi-gradient descent learning mode is proposed to better fit the internal state of the system, and a rolling training is used to implement an online prediction logic. Based on the Lyapunov second method, we discuss the stability of the system, the result shows that when the training error of neural network is sufficiently small, the system is asymptotically stable. With its application to the estimation of time-varying parameters of a missile dual control system, the LSTM-EKF shows better filtering performance than the EKF and adaptive EKF(AEKF) when there exist large uncertainties in the system model.展开更多
基金Supported by the National Natural Science Foundation of China (11161027)。
文摘Projective synchronization problems of a drive system and a particular response network were investigated,where the drive system is an arbitrary system with n+1 dimensions;it may be a linear or nonlinear system,and even a chaotic or hyperchaotic system,the response network is complex system coupled by N nodes,and every node is showed by the approximately linear part of the drive system.Only controlling any one node of the response network by designed controller can achieve the projective synchronization.Some numerical examples were employed to verify the effectiveness and correctness of the designed controller.
文摘为了提高控制器局域网络(controller area network,CAN)通信的实时性,文章基于时间触发CAN(time-triggered CAN,TTCAN)协议,采用verilog硬件描述语言设计实现TTCAN总线控制器。该控制器可在经典CAN模式与TTCAN模式之间进行切换,同时兼容可变速率CAN(CAN with flexible data rate,CAN FD)协议下的高速通信。实验结果证明,相较于经典CAN总线控制器,该TTCAN总线控制器能够减少在高总线负载率下周期性报文的发送延时,在全波特率范围内且总线负载率大于等于60%的情况下,能够减少75%以上的CAN报文发送延时。
文摘森林火灾初期控制尤为重要,目前我国小型的四驱森林消防车的电气控制系统多由传统的电气元件组合而成,存有布线安装复杂、故障率高、操作步骤多等问题。控制器局域网(Controller Area Network,CAN)总线+PLC控制技术具有良好的人机操作界面、一键式控制功能和安全保护等功能操作简便,以皮卡森林消防车为研究对象,研究了CAN总线技术在皮卡森林消防车上的集成技术应用、软件研发和结合方法,并进行实践测验。结果得出,CAN总线技术可以在该类型消防车上进行安装和使用,不仅促进了皮卡消防车通信系统的先进性和灵活性,同时提高了操作的便捷性、控制的稳定性和准确性,还大幅度提升森林水罐消防车系统的性能及操作性;对拓展森林消防车以及在其他特种车辆的控制系统和功能性具有重要作用和意义。
基金supported by Inha University Research Grant,Korea
文摘A wireless body area network offers cost-effective solutions for healthcare infrastructure. An adaptive transmission algorithm is designed to handle channel efficiency, which adjusts packet size according to the difference in feature-point values that indicate biomedical signal characteristics. Furthermore, we propose a priority-adjustment method that enhances quality of service while guaranteeing signal integrity. A large number of simulations were carried out for performance evaluation. We use electrocardiogram and electromyogram signals as reference biomedical signals for performance verification. From the simulation results, we find that the average packet latency of proposed scheme is enhanced by 30% compared to conventional method. The simulation results also demonstrate that the proposed algorithm achieves significant performance improvement in terms of drop rates of high-priority packets around 0.3%-0.9 %.
基金Project(2010-0020163) supported by Inha University Research and by Basic Science Research Program through the National Research Foundation of Korea(NRF) Funded by the Ministry of Education, Korea
文摘A wireless body area network (WBAN) allows integration of low power, invasive or noninvasive miniaturized sensors around a human body. WBAN is expected to become a basic infrastructure element for human health monitoring. The Task Group 6 of IEEE 802.15 is formed to address specific needs of body area network. It defines a medium access control layer that supports various physical layers. In this work, we analyze the efficiency of simple slotted ALOHA scheme, and then propose a novel allocation scheme that controls the random access period and packet transmission probability to optimize channel efficiency. NS-2 simulations have been carried out to evaluate its performance. The simulation results demonstrate significant performance improvement in latency and throughput using the proposed MAC algorithm.
基金the National Natural Science Foundation of China(Grant No.12072090).
文摘This paper investigates interception missiles’trajectory tracking guidance problem under wind field and external disturbances in the boost phase.Indeed,the velocity control in such trajectory tracking guidance systems of missiles is challenging.As our contribution,the velocity control channel is designed to deal with the intractable velocity problem and improve tracking accuracy.The global prescribed performance function,which guarantees the tracking error within the set range and the global convergence of the tracking guidance system,is first proposed based on the traditional PPF.Then,a tracking guidance strategy is derived using the integral sliding mode control techniques to make the sliding manifold and tracking errors converge to zero and avoid singularities.Meanwhile,an improved switching control law is introduced into the designed tracking guidance algorithm to deal with the chattering problem.A back propagation neural network(BPNN)extended state observer(BPNNESO)is employed in the inner loop to identify disturbances.The obtained results indicate that the proposed tracking guidance approach achieves the trajectory tracking guidance objective without and with disturbances and outperforms the existing tracking guidance schemes with the lowest tracking errors,convergence times,and overshoots.
文摘In this paper,an intelligent control method applying on numerical virtual flight is proposed.The proposed algorithm is verified and evaluated by combining with the case of the basic finner projectile model and shows a good application prospect.Firstly,a numerical virtual flight simulation model based on overlapping dynamic mesh technology is constructed.In order to verify the accuracy of the dynamic grid technology and the calculation of unsteady flow,a numerical simulation of the basic finner projectile without control is carried out.The simulation results are in good agreement with the experiment data which shows that the algorithm used in this paper can also be used in the design and evaluation of the intelligent controller in the numerical virtual flight simulation.Secondly,combined with the real-time control requirements of aerodynamic,attitude and displacement parameters of the projectile during the flight process,the numerical simulations of the basic finner projectile’s pitch channel are carried out under the traditional PID(Proportional-Integral-Derivative)control strategy and the intelligent PID control strategy respectively.The intelligent PID controller based on BP(Back Propagation)neural network can realize online learning and self-optimization of control parameters according to the acquired real-time flight parameters.Compared with the traditional PID controller,the concerned control variable overshoot,rise time,transition time and steady state error and other performance indicators have been greatly improved,and the higher the learning efficiency or the inertia coefficient,the faster the system,the larger the overshoot,and the smaller the stability error.The intelligent control method applying on numerical virtual flight is capable of solving the complicated unsteady motion and flow with the intelligent PID control strategy and has a strong promotion to engineering application.
文摘In this paper, a filtering method is presented to estimate time-varying parameters of a missile dual control system with tail fins and reaction jets as control variables. In this method, the long-short-term memory(LSTM) neural network is nested into the extended Kalman filter(EKF) to modify the Kalman gain such that the filtering performance is improved in the presence of large model uncertainties. To avoid the unstable network output caused by the abrupt changes of system states,an adaptive correction factor is introduced to correct the network output online. In the process of training the network, a multi-gradient descent learning mode is proposed to better fit the internal state of the system, and a rolling training is used to implement an online prediction logic. Based on the Lyapunov second method, we discuss the stability of the system, the result shows that when the training error of neural network is sufficiently small, the system is asymptotically stable. With its application to the estimation of time-varying parameters of a missile dual control system, the LSTM-EKF shows better filtering performance than the EKF and adaptive EKF(AEKF) when there exist large uncertainties in the system model.
