Structural Design of Composite Nonlinear Feedback Control for Nonminimum Phase Linear Systems with Input Saturation

The general design procedure of composite nonlinear feedback (CNF) control does not consider the structure information of the system. As a result, the tuning of the nonlinear feedback gain is very difficult, especially for nonminimum phase systems. In this paper, a novel design method is proposed to construct a CNF control law by using the structure information of the system in a special coordinate basis (SCB) form. First, the system is transformed into the SCB form, in which the system is divided into three parts, i.e., stable zero dynamics part, unstable zero dynamics part, and integration part. For a nonminimuni phase linear system, a virtual linear feedback gain is designed to stabilize the unstable zero dynamics. With this virtual gain, the system can be transformed to an integration system which is connected to a stable system. Then, the CNF control law is tuned only for the integration part of the system. Since the target system is an integration system, the proposed method simplifies the tuning of the nonlinear function in the CNF design

物体在不可压缩流场中所受的流体动力表达式

为统一有粘和无粘不可压缩流场中的流体动力表达式,在允许滑移边界条件的情况下,重新推导了不可压缩流场中运动体的流体动力表达式.根据流场动量定理将流体动力表示为无穷远边界上流场应力的积分与流场动量变化率积分的代数和;再利用导数矩转换(DMT)公式分别将这两个积分结果进行分解,并根据速度在无穷远处的渐近特性将这些分解结果组合并简化成流场第一涡量矩的积分及流场在物面边界上切向速度矩的积分之和,得到了新的流体动力表达式.理论分析和算例证明了这种新的流体动力表达式在无粘流的情况下收敛于Lamb的流体动力表达式,而在有粘流的情况下与涡动力学理论一致.国家自然科学基金(11072028,61273199);;福建省自然科学基金(2016J01030

Speed Control of DC Motor using Composite Nonlinear Feedback Control

This paper presents the design of the composite nonlinear feedback (CNF) control law for DC motor speed control. First, a linear feedback control law is designed such that the closed-loop system under this linear control law has small damping ratio. Then, a nonlinear feedback part is designed based on this linear feedback law. The nonlinear function of the nonlinear feedback part is tuned by formulating the parameter tuning problem into a minimization problem. The minimization problem is solved by Hooke-Jeeves algorithm. The well designed CNF control law results in a satisfied transient performance with small overshoot, and fast rising time and settling time

Parameters Optimization of Robot Arm PID Controllers Based on PSO Algorithm

机械臂的工作环境复杂,对其工作的响应指标要求较高。PId控制受限于机械臂的数学模型的复杂性与不精确性,导致经典的参数整定方法在实际生产中适应性不良或性能欠佳。文章基于MATlAb/SIMulInk将PSO算法(粒子群优化算法)用于机械臂PId控制器的参数优化中,通过对3关节连杆机械臂单次拉伸动作的建模仿真研究,结果表明:使用此方法后,机械臂各关节响应的调节时间和超调量都得到明显的优化。The robot arm always runs in a complex condition,and the demand for its state response performance index is high.PID control is restricted to the complicacy and the inexactitude of robot arm's mathematics model,which leads the classical parameters tuning methods to the maladjustment and the suboptimal performance in real operating.And the PSO algorithm is presented and applied to optimize PID parameters in robot arm based on MATLAB/Simulink.According to the simulation of a stretching movement in a 3-joint-robot arm,the numerical simulation shows that by this method the setting time and overshoot of every joint in the robot arm present optimized distinctly.国家自然科学基金(60704042);福建省自然科学基金(2008J0033

An Improved Graph Drawing Algorithm for Email Networks

This paper addresses the graph drawing problem for email networks. First, the graph drawing problem is formulated as a minimization problem. Then, a genetic algorithm based graph drawing method is proposed by solving the minimization problem. By taking into account the small-world property of the email-networks, the proposed method improved the force-directed graph drawing algorithm to draw the graph more intuitively and aesthetically. It also speeds up the graph drawing algorithm by ignoring repulsive force far away from the vertex, and prevents the nearly disconnected graph from being pushed to the border. Moreover, the key cliques of the email networks are placed in the central of the layout. Experiment tests show that the proposed method has better performance in satisfying the aesthetic criterions and time consumption

An approach to neural control of a class of strict-feedback nonlinear systems

研究一类不确定严反馈非线性系统的跟踪控制问题.通过采用单一神经网络逼近系统的所有未知部分,提出一种新的鲁棒自适应控制设计方法.该方法能直接给出实际控制律和自适应律,有效地解决现有方法中存在的控制设计复杂和计算负担重等问题.稳定性分析表明,闭环系统所有信号是半全局一致最终有界的,并且通过调整控制参数可使跟踪误差任意小.仿真结果验证了所提出方法的有效性.The problem of tracking control is studied for a class of uncertain strict-feedback nonlinear systems.A new robust adaptive control design approach is presented by approximating all the unknown parts of the system with a single neural network.By using this approach,the actual control law and the adaptive law of the controller can be given directly,and the problems,such as control design complexity and high computational burden,are dealt with effectively.The stability analysis shows that the closed-loop system signals are semi-globally uniformly ultimately bounded,and the tracking error can be made arbitrary small by choosing control parameters.Simulation results show the effectiveness of the proposed approach.国家自然科学基金项目(61074017;61074004;61273137;51209026); 辽宁省高等学校优秀人才支持计划项目(2009R06); 中央高校基本科研业务费项目(017004

Robust Controller Design of New Style Satellite′s Attitude Movement

研究H∞/μ综合方法在新型卫星姿态运动的鲁棒控制器设计中的应用.讨论新型卫星姿态运动中卫星姿态控制以及挠性体振动抑制和液体晃动抑制等问题，同时阐述一个确定低阶控制器阶数的判据.The robust controller design of liquid satellite′s attitude movement was studied by using H ∞/μ method.Attitude control, as well as the suppression of the flexible structure′s vibration and the liquid sloshing, was discussed.A test for deciding the order of reduced order controller was formulated.中国空间技术研究院预研资

Output feedback CNF control for output regulation problem of linear system with input saturation

Conference Name:2013 25th Chinese Control and Decision Conference, CCDC 2013. Conference Address: Guiyang, China. Time:May 25, 2013 - May 27, 2013.To improve the transient performance, the composite nonlinear feedback (CNF) control technique is introduced to solve the output regulation problem of linear systems with input saturation. Under the assumption that both the states of plant and exo-system are not measurable for feedback, an full state observer is designed to construct an output feedback CNF control law. The output feedback CNF controller is constructed based on a state feedback control law that solves the output regulation problem and the state observer. The solvability of the output regulation problem by output feedback CNF control is established which shows that the nonlinear feedback part does not change the solvability condition of the output regulation problem. The introducing of nonlinear feedback part in the CNF control law provides an extra degree of freedom to improve the transient performance. By appropriately choosing the linear feedback gain and the nonlinear feedback gain in the CNF control law can significantly improve the transient performance of the controlled output which is illustrated by a disturbance rejection problem. ? 2013 IEEE

Structural Design of Composite Nonlinear Feedback Control for Multivariable Systems with Input Saturation

This paper investigates the design of the composite nonlinear feedback (CNF) control law for multivariable linear systems with input saturation. In the existing design procedure of the CNF control for multivariable systems, the nonlinear function is given by an m dimensional matrix in a diagonal form, where m is the number of system inputs. However, the inputs and the outputs of the system are coupled heavily in many cases. Thus, it is very difficult to tune the nonlinear functions of the diagonal matrix in the design of the CNF control. This paper proposes a more efficient design procedure for the CNF control by using the structure information of the system in a special coordinate basis (SCB) form. The proposed design procedure gives a clear map on how to select the structure of the nonlinear feedback gain, and how to tune the nonlinear functions in the CNF control