晋东南-荆门特高压线路保护浅析

介绍了晋东南—南阳-荆门特高压交流1000kV试验示范工程的线路、变压器、电抗器、断路器等保护的配置情况,重点分析了特高压线路保护联跳三相新功能的技术要求和厂家实现该功能的保护逻辑,论述了采用纵联标识码后光纤差动保护和光纤纵联距离保护在通道自环、同步采样、通讯时钟等通讯方式的设定方法,简要介绍了特高压经高阻接地故障的新特点,并对比分析了南瑞继保和四方线路保护实现上述功能的异同和有别于超高压线路保护的特点。     

基于领航跟随法的多AUV编队控制算法研究

针对已知路径下基于领航者的多自主水下机器人(AUV)编队队形控制问题,提出了一种AUV路径控制和编队协调控制相结合的新型编队控制器。其中,AUV的路径跟踪控制采用反步滑模控制器,将AUV位置、姿态和时变速度跟踪转化虚拟速度控制,使AUV能达到期望的位置、速度等,避免了反步控制中的奇异值问题,并能够很好实现不确定的模型的控制,同时又提高了跟随者协同定位精度;在路径跟踪控制基础上,编队协调控制器将领航者与跟随者的位置误差控制转化为跟随者的速度误差控制,使跟随者能快速达到期望位置,从而使所有AUV实现期望的队形并保持。仿真实验对该控制策略进行了可行性验证,结果表明,该算法提高了编队的响应速度、控制精度和稳定性;再应用3台AUV进行了湖上试验验证,证明了该控制策略的有效性,能有效应用到实际中。     

Precise contour following for biaxial systems via an A-type iterative learning cross-coupled control algorithm

This paper proposes an A-type iterative learning cross-coupled control (CCC) algorithm for biaxial systems. An algebraic equation based contour error model is used as the CCC input. This model has the advantage that it is zero if and only if the real value vanishes. The iterative learning CCC is designed to make its input converge to zero. Hence, it is expected to that the contour error will converge to zero as well. After analyzing the control algorithm convergence condition in the frequency domain, the proposed method is implemented on a motion stage. Experimental results show that the algorithm perfectly follows contours as the cycles approach infinity regardless of whether tracking errors are small or large.     

一种新的移动机器人跟踪控制方法

以前轮转向、后轮驱动的四轮移动机器人为研究对象 ,建立了它的运动学模型 ,提出了一种鲁棒性好 ,实时性强 ,易于实现的跟踪控制方法。此方法将被跟踪路径划分成若干微小线段 ,应用以微小直线段代替曲线的方法 ,来进行分段跟踪。理论分析表明 ,该方法能保证系统的稳定性。采用此方法 ,计算简单 ,实现容易 ,并使得移动机器人跟踪的实时性、精确性得到提高。通过多种参考路径跟踪的仿真计算和实时跟踪控制试验 ,其结果均说明此方法是正确和有效的。     

煤电钻综合保护装置的改进分析

通过分析和计算说明老式煤电钻综合保护装置在漏电保护和执行电路中存在的问题．实践证明,经过改进的新式煤电钻综合保护功能得到了进一步完善,使用更加安全．     

Finite-time path following control for a stratospheric airship with input saturation and error constraint

This paper addresses the finite-time path following control problem for an under-actuated stratospheric airship with input saturation, error constraint, and external disturbances. To handle the adverse effect of input saturation, anti-windup compensators are employed and finite-time convergence of the saturated control solution is established. Error constraints of airship position and attitude are handled by incorporating a tan-type barrier Lyapunov function (TBLF) in guidance and attitude control schemes. Backstepping design is presented with the anti-windup compensators, the TBLF, and nonlinear disturbance observers which estimate the external disturbances. Stability analysis shows that the tracking errors of the airship position converge into a small set around zero within finite-time, the constrained requirements on the airship position and attitude are not violated during operation, and all closed-loop signals are guaranteed to be uniformly ultimately bounded. Compared with the conventional control scheme, simulation results illustrate that the proposed finite-time controller offers a faster convergence rate and a higher path following accuracy for the stratospheric airship.     

Leader‐following consensus with disturbance rejection for uncertain Euler‐Lagrange systems over switching networks

In this paper, the leader‐following consensus with disturbance rejection problem of uncertain Euler‐Lagrange systems is studied by the adaptive distributed observer approach. We first present a key lemma that guarantees the existence of an exponentially convergent adaptive distributed observer for linear leader systems without exponential growing modes over jointly connected switching and directed communication networks. This lemma also provides a specific Lyapunov function for the error dynamics of the adaptive distributed observer, which will play a crucial role in establishing one of the main results. A special case of this result where there is no disturbance will extend the existing result for a neutrally stable leader system and undirected communication networks to the case where the communication networks are directed and the leader's positional signal includes the class of ramp signals. Two examples will be given to demonstrate the effectiveness of the new results.     

基于ROS的移动机器人视觉跟随系统设计

视觉跟随是机器人领域中一个比较重要的部分,可以应用在仓储搬运、安防、军事等多种领域。由于传统算法存在当背景比较复杂的情况下无法有效跟踪目标、对跟踪目标和外部环境的分辨率要求高所以只能进行辅助跟踪、计算量大无法满足实时性要求等问题。本文采用KCF算法设计,设计了基于ROS的移动机器人视觉跟随系统,利用循环矩阵在傅里叶空间可对角化的性质,从而使得矩阵运算被转化成元素的点乘,减少了计算量从而提高了运算速度,满足了算法的实时性要求。经过实验和数据分析,本移动机器人可以实时有效的跟随指定目标实现视觉跟随功能。     

Cooperative path following of constrained autonomous vehicles with model predictive control and event‐triggered communications

We present a solution to the problem of multiple vehicle cooperative path following (CPF) that takes explicitly into account vehicle input constraints, the topology of the intervehicle communication network, and time‐varying communication delays. The objective is to steer a group of vehicles along given spatial paths, at speeds that may be path dependent, while holding a feasible geometric formation. The solution involves decoupling the original CPF problem into two subproblems: (i) single path following of input‐constrained vehicles and (ii) coordination of an input‐constrained multiagent system. The first is solved by adopting a sampled‐data model predictive control scheme, whereas the latter is tackled using a novel distributed control law with an event‐triggered communication (ETC) mechanism. The proposed strategy yields a closed‐loop CPF system that is input‐to‐state‐stable with respect to the system's state (consisting of the path following error of all vehicles and their coordination errors) and the system's input, which includes triggering thresholds for ETC communications and communication delays. Furthermore, with the proposed ETC mechanism, the number of communications among the vehicles are significantly reduced. Simulation examples of multiple autonomous vehicles executing CPF maneuvers in 2D under different communication scenarios illustrate the efficacy of the CPF strategy proposed.     

A novel 3D path following control framework for robots performing surface finishing tasks

We describe a novel 3D path following control framework for articulated robots in applications where constant speed travel along a path is desirable, such as robotic surface finishing tasks. Given the desired robot configuration sequence with a list of waypoints along a path, a trajectory optimization scheme based on direct collocation is proposed to determine the Cartesian path and the maximum constant translation speed that are dynamically feasible. Employing the Hermite–Simpson collocation method, a Cartesian path is developed that not only preserves the characteristics of the original motion sequence but also satisfies the physical requirements of the robot kinematics and dynamics. Since joint velocity control is quite common in many industrial robots, we consider a 3D kinematic control in the robot tool frame with control inputs as rate of change of orientation. The objective for the translation motion is to achieve constant speed along the path tangent direction, and that of the orientation control is to orient the robot properly based on the path provided by a converging path planner. We describe the optimization procedure employed with the direct collocation method to obtain the desired Cartesian path, an arc-length based re-parametrization of the desired path, and a path planner that provides a converging path to the desired path. To perform the surface finishing operation, we further present the joint space control law that is converted from the synthesis of the proposed path following and impedance force control in the tool frame. To verify and evaluate the performance of the proposed framework, we have conducted extensive experiments with a six degrees-of-freedom (DOF) industrial robot for several paths that can be employed for surface finishing of a variety of industrial parts.