PNG复杂曲面纹理映射的仿真方法

随着PNG图片越来越广泛的应用,所以研究复杂曲面纹理映射的方法有着重要的意义.为了在保持低存储量,小计算量的同时,针对PNG图片的复杂曲面自动纹理映射的变形,根据纹理扰动的缺点.提出了一种改进的复杂曲面纹理映射的方法,通过利用解二次椭圆偏微分方程,来得到任意曲面到平面的共形映射.方法不但可以自动分配纹理坐标到复杂的没有起伏的曲面,而且可以有效地克服复杂曲面的自动纹理映射的变形.避免纹理扰动,很好地解决了纹理的自动映射.     

Stability of solutions of stochastic functional-differential equations with poisson switchings and entire prehistory

The Markov properties of the solutions of Ito-Skorokhod stochastic functional-differential equations (SFDEs) with entire prehistory are considered, the concept of a weak infinitesimal operator is introduced for a Markov process that is a solution of an SFDE, and the strong solution of the SFDE is analyzed for stability. Translated from Kibernetika i Sistemnyi Analiz, No. 1, pp. 123–134, January–February 2009.     

模拟时滞化学反应系统中的DK-Leap算法

最近发展的可精确模拟时滞化学反应系统的动力学状态的时滞随机模拟算法(delay stochastic simulation algorithm,DSSA)的模拟效率很低。本文提出了一个模拟时滞化学反应系统的加速DK-Leap(Delay K-Leap)算法。DK-Leap算法首先确定满足Leap条件的总反应次数K,然后利用得到τ的概率密度函数随机确定时间区间[t,t τ)。由于每个反应通道的反应次数由K确定,该算法可得到较好的模拟精度。数值试验表明DK-Leap算法在模拟时滞化学反应系统时能取得很好的性能。     

点火系对环形线圈车辆检测器辐射干扰的仿真

环形线圈车辆检测器是利用电涡流检测原理工作的一种车辆检测设备,存在易受电磁干扰影响的缺陷.汽车点火系是环形线圈车辆检测器工作环境中存在的强大宽带电磁干扰源.针对汽车点火系对环形线圈车辆检测器可能产生的辐射干扰,采用基于有限积分技术的仿真软件进行了数值仿真.仿真结果表明,在不考虑汽车金属外壳屏蔽作用,并且点火系恰好位于环形线圈正上方的情况下,汽车点火系产生的辐射电场对环形线圈车辆检测器正常工作有严重影响,必须对其采取一定的屏蔽措施.     

Event-triggered control for stochastic systems with multiple delays

This paper investigates the stabilization problem for continuous-time stochastic systems with multiple delays under continuous event-triggered mechanisms, of which both static case and dynamic case are considered individually. In order to avoid zeno phenomenon in every sample path, a suspension time after each successful execution is forced for our event-triggered mechanisms, resulting in intermittent detection of system states. Under such control strategy, we deduce mean square exponential stability of stochastic systems with multiple delays by means of Hanalay-type inequality and obtain a delay-dependent-based and less-conservative stabilization criterion without involving the upper bound of time delays. Besides, a co-design procedure is proposed for linear controller and event-triggered mechanisms. In the end, an illustrative example is presented to show effectiveness of the proposed co-design procedure and contrasts the system performance under static and dynamic event-triggered mechanisms.     

Adaptive neural network dynamic event-triggered control for strong interconnected stochastic nonlinear systems with output constraint

This paper proposes a dynamic event-triggered mechanism based command filtered adaptive neural network (NN) tracking control scheme for strong interconnected stochastic nonlinear systems with time-varying output constraints. By designing a state observer, the unmeasured states of the systems can be estimated. The NNs are utilized to handle the unknown intermediate functions. In the controller design process, the asymmetric time-varying barrier Lyapunov functions are used to guarantee that the systems outputs do not violate the constraint regions. By integrating the command filter with variable separation technique, the controller design process is more simple, and the problem of algebraic-loop can be solved which caused by interconnected functions. According to the Lyapunov stability theory, it can be ensured that all signals of the systems are bounded in probability. Finally, the availability of the developed control scheme can be showed by the simulation example.     

Fully distributed optimization of second-order systems with disturbances based on event-triggered control

This paper studies the distributed optimization problem of second-order multiagent systems containing external disturbances. To reject the external disturbances and lead agents' states to converge to the optimal consensus point, an adaptive event-triggered controller is proposed based on the internal model principle. With the adaptive mechanism, both the controller and the event-triggering condition do not contain the parameters related to global information, such as the maximum Lipschitz constant and the minimum strongly convex constant of local cost functions, and hence the event-triggered controller is fully distributed. By utilizing the event-triggered scheme, the consumption of communication among neighbors and the computing resources are saved. Furthermore, with the Lyapunov analysis framework, the optimal consensus can be proved to achieve and Zeno behavior is excluded from the event-triggering condition. Finally, the effectiveness of the proposed protocol is verified by numerical simulations.     

Nonlinear cascade control of an electro-hydraulic actuator with large payload variation

Electro-hydraulic actuators have been widely used in industrial production, but the unknown variable payload seriously affects its position control accuracy. Therefore, a radial basis function neural network disturbance observer is designed to estimate the lumped disturbance force through strong online learning ability in the absence of force sensor. Besides, a nonlinear cascade controller with double loop structure is proposed in this paper. A global fast terminal sliding mode control method is firstly applied in the outer loop position system, which can eliminate chattering and improve convergence speed comparing to traditional sliding mode control. The inner loop force system adopts a backstepping control method to calculate the actual input of the whole system. Theoretical analysis indicates that the proposed controller is stable even if existing time-variant disturbance. Moreover, three comparative controllers are designed and tested in both simulations and experiments. Comparative results show that the developed method has absolute average errors of 1.14 and 0.49 mm in different position tracking, which means more satisfactory tracking performance compared to the contrast controllers.     

Inverse-compensation-based DETC for nonlinear hysteresis system with disturbance

To control a nonlinear system with both hysteresis and disturbance, it is necessary to establish a hysteresis model and improve the disturbance rejection ability. However, the input signal implicitly involved in the classical hysteresis model can lead to difficulty in constructing a compensator. In this study, a hysteresis model in explicit form is proposed with a bounded auxiliary variable. Then, a model-based inverse is constructed for approximate compensation for the hysteresis. Moreover, the compensation error, which is considered a part of the disturbance, is proved to be bounded. Disturbance estimation triggered control (DETC) is utilized to address the compensation error coupled with the external disturbance. According to the disturbance effect indicator (DEI), DETC can improve the system control performance by considering the disturbance effect judgment. Experimental results are presented to illustrate the potential of the proposed technique.