欠驱动岸边集装箱起重机防摆控制方法研究综述

针对控制领域的研究热点之一非线性、欠驱动岸边集装箱起重机防摆控制问题,从欠驱动系统的概念和岸边集装箱起重机动力学模型出发,详细分析研究的必要性、国内外研究现状和难点。最后,分析现有控制方法存在的主要问题,并对岸边集装箱起重机防摆控制方法进一步的发展方向进行了展望。     

一类欠驱动系统的非线性输出跟踪控制

针对一类模型结构为非下三角的欠驱动系统,在反步法的框架下研究了其非线性输出跟踪控制问题．鉴于在此类欠驱动系统的反步法设计中,沿用一般下三角系统的偏差难以镇定全部的偏差动态,由此引入了“联系函数”的概念．在反步法设计中,构造了异于下三角系统的偏差,设计了状态反馈跟踪控制器,保证了系统偏差的全局一致渐近稳定性．仿真结果表明...     

一类欠驱动机械系统的模糊与变结构控制

针对体操机器人这类欠驱动机械系统,提出一种模糊与变结构控制策略.首先用逻辑模糊控制实现快速平滑的摇起;然后用模糊变结构控制确保从摇起区快速进入平衡区;最后用基于Takagi-Sugeno模糊模型的模糊控制达到较大范围内的平衡控制.     

一类欠驱动机械系统的全局鲁棒控制

针对具有质心参数不确定性的Acrobot系统,提出一种全局的鲁棒控制方法.首先,给出系统具有质心参数不确定的系统模型;其次在摇起区,分析系统不确定性条件下的能量变化情况,基于能量不断增加的思想设计出摇起控制器;在平衡区,把系统的不确定性转化为模型状态矩阵的不确定性,引入H标准设计方法,得出存在H状态反馈控制器的充要条件,通过求解线性矩阵不等式使系统有效地克服不确定性的影响实现二次稳定;最后通过仿真实验验证了所提方法的有效性.     

欠驱动机器人控制策略综述

欠驱动机器人是指独立控制输人量少于系统自由度的一类机器人,具有重量轻、成本低、能耗低等众多优点,目前已引起学者们的广泛关注,介绍了欠驱动机器人控制器设计的六类策略,分析了各类策略的应用及效果,如何将鲁棒控制与其它控制策略相结合,开发出更实用、性能更优越的控制策略,有待于进一步研究.     

一类非确定欠驱动系统的串级模糊滑模控制

本文针对一类含有非确定项的欠驱动系统提出了一种串级模糊滑模控制方法.该方法先选取状态变量中两个相关联的系统状态构造第一级滑动平面,然后将第一级滑模函数作为一个广义状态,与剩下系统状态中的一个状态构造第二级滑动平面,直到所有的系统状态都包含在内构造最后一级滑动平面.同时考虑到系统模型中存在的不确定项,利用模糊逻辑的逼近功能进行估计,文中采用Lyapunov方法求取了控制器的控制律以及模糊逼近的有关参数的自适应律.该串级模糊滑模控制器能够保证各级滑动平面的稳定性,并且在仿真实验中得到了验证.     

欠驱动基准系统的约束控制

针对一种欠驱动基准系统,具有旋转激励的平移振荡器(translation oscillators with rotating actuator,TORA)系统,本文首次提出了一种具有约束的控制方法.该方法不仅可以保证闭环系统的稳定性,而且能够保证旋转小球在预设的范围内转动.相比已有控制方法,本文所提方法可以预设小球的转动范围以避免不理想的\"循环\"行为.具体而言,首先对系统的总机械能进行了详细分析;随后在其总机械能的基础上通过能量整形构造出一个新颖的能量函数;最后基于所构造的能量函数提出了一种具有约束的控制器,采用Lyapunov方法及La Salle不变性原理证明了相应闭环系统的稳定性.通过与已有方法进行仿真对比可知,本文方法在镇定控制与约束控制方面均表现出良好的控制性能.     

基于DSP的欠驱动体操机器人的摇起控制设计

针对欠驱动机器人控制系统,给出一种基于DSP控制的类人形的三关节欠驱动体操机器人。首先以ADSP2181为核心设计出控制器,通过高速PCI总线与上位机PC通讯,采用直流电机伺服控制。然后依据建立的体操机器人动力学模型提出基于能量增加的正弦和斜坡函数输入方式,经对体操机器人作摇起控制实验,实验显示,设计的三关节欠驱动体操机器人控制系统满足实时性、稳定性和准确性要求。     

欠驱动两足步行机器人侧向稳定控制方法研究

以欠驱动两足步行机器人为对象研究其侧向运动稳定控制问题。首先分析引起机器人侧向运动不稳定的原因,然后提出步宽控制和侧向力矩补偿两种控制策略。步宽控制通过控制机器人侧向落脚位置,使其侧向运动周期与前向周期趋于一致实现侧向运动稳定。力矩补偿控制通过在踝关节引入侧向控制力矩,使侧向运动与前向运动协调一致实现侧向运动稳定。仿真实验表明,机器人实现了稳定的3D动态行走,达到了预期的控制效果。     

Periodic motion planning and control for underactuated mechanical systems

We consider the problem of periodic motion planning and of designing stabilising feedback control laws for such motions in underactuated mechanical systems. A novel periodic motion planning method is proposed. Each state is parametrised by a truncated Fourier series. Then we use numerical optimisation to search for the parameters of the trigonometric polynomial exploiting the measure of discrepancy in satisfying the passive dynamics equations as a performance index. Thus an almost feasible periodic motion is found. Then a linear controller is designed and stability analysis is given to verify that solutions of the closed-loop system stay inside a tube around the planned approximately feasible periodic trajectory. Experimental results for a double rotary pendulum are shown, while numerical simulations are given for models of a spacecraft with liquid sloshing and of a chain of mass spring system.     

Sliding mode coordination control for multiagent systems with underactuated agent dynamics

In this paper, we develop a new integrated coordinated control and obstacle avoidance approach for a general class of underactuated agents. We use graph-theoretic notions to characterise communication topology in the network of underactuated agents as determined by the information flow directions and captured by the graph Laplacian matrix. Obstacle avoidance is achieved by surrounding the stationary as well as moving obstacles by elliptical or other convex shapes that serve as stable periodic solutions to planar systems of ordinary differential equations and using transient trajectories of those systems to navigate the agents around the obstacles. Decentralised controllers for individual agents are designed using sliding mode control approach and are only based on data communicated from the neighbouring agents. We demonstrate the efficacy of our theoretical approach using an example of a system of wheeled mobile robots that reach and maintain a desired formation. Finally, we validate our results experimentally.     

Sliding mode control of a class of underactuated systems

A sliding mode control approach is proposed to stabilize a class of underactuated systems which are in cascaded form. This class of underactuated systems can represent many real applications after transformations. In the controller design, the sliding surface is designed to stabilize the indirectly controlled modes. Its insensitivity to the model errors, parametric uncertainties and other disturbances and its ability to globally stabilize the system are two advantages of the sliding mode controller.     

Hybrid control for a class of underactuated mechanical systems

This paper considers a stabilizing hybrid scheme to control a class of underactuated mechanical systems. The hybrid controller consists of a collection of state feedback controllers plus a discrete-event supervisor. When the continuous-state hits a switching boundary, a new controller is applied to the plant. Lyapunov theory is used to determine the switching boundaries and to guarantee the stability of the closed-loop hybrid system. This approach is applied to the well-known swing up and balancing control problem of the inverted pendulum     

Hybrid position/force tracking for a class of constrained mechanical systems

We study the hybrid tracking problem for a class of mechanical systems, described by Euler-Lagrange equations of motion, subject to a set of holonomic and/or nonholonomic constraints in a unified fashion. Based on a QR-like decomposition of the constraint Jacobian, it is shown that the constraint-force free and reduced constrained motions of constrained mechanical systems can be naturally separated. A new hybrid control is proposed for the decomposed motions to achieve simultaneous, independent position and force tracking. Some comments about the applicability of main tracking result are given.     

Fault tolerant cooperative control for a class of nonlinear multi-agent systems

This paper studies the target aggregation problem for a class of nonlinear multi-agent systems with the time varying interconnection topology. The general neighboring rule-based linear cooperative protocol is developed and a sufficient aggregation condition is derived. Moreover, it is shown that in the presence of agent faults, the target point is still reached by adjusting some weights of the cooperative protocol without changing the structure of the topology. An unmanned aerial vehicle team example illustrates the efficiency of the proposed approach.     

Affine and predictive control policies for a class of nonlinear systems

The input-state linear horizon (ISLH) for a nonlinear discrete-time system is defined as the smallest number of time steps it takes the system input to appear nonlinearly in the state variable. In this paper, we employ the latter concept and show that the class of constraint admissible N-step affine state-feedback policies is equivalent to the associated class of constraint admissible disturbance-feedback policies, provided that N is less than the system’s ISLH. The result generalizes a recent result in [Goulart, P. J., Kerrigan, E. C., Maciejowski, J. M. (2006). Optimization over state feedback policies for robust control with constraints. Automatica, 42(4), 523-533] and is significant because it enables one: (i) to determine a constraint admissible state-feedback policy by employing well-known convex optimization techniques; and (ii) to guarantee robust recursive feasibility of a class of model predictive control (MPC) policies by imposing a suitable terminal constraint. In particular, we propose an input-to-state stabilizing MPC policy for a class of nonlinear systems with bounded disturbance inputs and mixed polytopic constraints on the state and the control input. At each time step, the proposed MPC policy requires the solution of a single convex quadratic programme parameterized by the current system state.     

Switched seesaw control for the stabilization of underactuated vehicles

This paper addresses the stabilization of a class of nonlinear systems in the presence of disturbances, using switching controllers. To this effect we introduce two new classes of switched systems and provide conditions under which they are input-to-state practically stable (ISpS). By exploiting these results, a methodology for control systems design—called switched seesaw control—is obtained that allows for the development of nonlinear control laws yielding input-to-state stability. The range of applicability and the efficacy of the methodology proposed are illustrated via two nontrivial design examples. Namely, stabilization of the extended nonholonomic double integrator (ENDI) and stabilization of an underactuated autonomous underwater vehicle (AUV) in the presence of input disturbances and measurement noise.