Intelligent Integrated Control of Underactuated Mechanical Systems with Second-order Nonholonomic Constraints

This paper describes an intelligent integrated control of an acrobot, which is an underactuated mechanical system with second-order nonholonomic constraints. The control combines a model-free fuzzy control, a fuzzy sliding-mode control and a modelbased fuzzy control. The model-free fuzzy controller designed for the upswing ensures that the energy of the acrobot increases with each swing. Then the fuzzy sliding-mode controller is employed to control the movement that the acrobot enters the balance area from the swing-up area. The model-based fuzzy controller, which is based on a Takagi-Sugeno fuzzy model, is used to balance the acrobot. The stability of the fuzzy control system for balance control is guaranteed by a common symmetric positive matrix, which satisfies linear matrix inequalities.     

欠结构水下机器人的自适应位置跟踪控制器的设计

欠结构水下机器人的控制是一个具有很大难度的课题。研究了一种欠结构多方位智能机器人的跟踪问题，在机器人参数不确定及存在未知环境扰动的情况下，设计出了连续的自适应控制器，使得机器人可以自动地跟踪任意光滑的轨迹，并且跟踪误差收敛于半径为任意小的原点的邻域。Matlab仿真研究表明了该控制方案的有效性。     

Optimal motion planning of an underactuated spacecraft using wavelet approximate method

An optimal motion planning scheme using wavelet approximation is proposed for an underactuated spacecraft. The motion planning of an underactuated spacecraft can be formulated as an optimal control of a drift-free system. A cost functional is used to incorporate the control energy and the final state errors. The motion planning is to determine control inputs to minimize the cost functional. Using the method of wavelet, one can transform an infinite-dimensional optimal control problem to a finite-dimensional one and use Gauss-Newton algorithm to solve it for a feasible trajectory which satisfies nonholonomic constraints. The proposed scheme has been applied to a rigid spacecraft with two momentum wheels. The numerical simulation results indicate that optimal control with wavelet approximation is an effective approach to steering an underactuated spacecraft system from the initial configuration to the final configuration.     

欠驱动机械臂无源-自适应迭代学习控制

针对一类欠驱动串联机械臂,基于其动力学方程的变换,提出了一种分步控制策略。该策略首先利用全驱动关节与欠驱动关节之间的动力学耦合,驱使欠驱动关节达到理想位置进而对其进行锁定。由于欠驱动关节理想夹角的随机性,使得锁定欠驱动关节后的机械臂成为一结构不确定系统。针对此类系统,结合迭代学习和耗散控制理论,提出了一种无源-自适应迭代学习控制方法,使其能够进行轨迹跟踪。通过对三连杆机械臂的仿真验证了其有效性及实用性。     

The mechanism of HIT/DLR prosthetic hand

A multi-sensory five-fingered prosthetic hand has been designed on the basis of underactuated mechanism and coupling principle. The hand is much similar to the adult hand. Three motors actuate the thumb, the index finger and the other three fingers each. The hand comprises 13 joints. Actuated by a motor, the thumb can move along a conic surface, which is superior in appearance. Driven by another motor with springs as transmission elements, the mid finger, ring finger and little finger can envelop objects with complex shape. The sensory system and the appearance design are introduced. It was verified by experiments that the hand has strong capacity of self adaptation and can accomplish accurate and powerful grasp for objects with complex shape.     

船舶运动控制综述与展望

对欠驱动水面船舶的非线性控制做了简要的论述,首先说明了问题的背景和重要意义,其次介绍了欠驱动船舶常用的非线性控制方法,最终提出了该领域的一些开放性的问题。     

平面欠驱动两杆柔性机械臂的全局稳定控制

针对平面欠驱动两杆柔性机械臂,该文提出一种新的控制策略,实现了机械臂的全局稳定控制目标。首先,为机械臂系统引入一个同胚坐标变换,将其变换为一个结构简单的新系统;然后,将新系统分离为线性和非线性2个部分,利用等价输入干扰的概念为新系统设计控制器,以实现新系统的全局稳定控制目标,并通过坐标变换的同胚性使原机械臂系统的全局稳定控制问题得以解决。该文所提控制方法仅需利用机械臂的位置量信息设计控制器,这不仅能降低控制系统成本,而且还能有效避免速度噪音对控制性能的影响。数值仿真结果显示,所提的控制策略在机械臂系统的稳定运动过程及稳定时间等性能方面,均能达到令人满意的控制效果。     

高性能欠驱动水面机器人的有限时间跟踪控制

针对一类非完全对称的高性能欠驱动水面机器人系统,提出一种有限时间收敛的跟踪控制器.利用全局微分同胚变换得到非线性级联系统的形式,将原系统的跟踪控制问题转化为非线性级联系统的控制问题.基于有限时间Lyapunov理论,设计一种有限时间控制器,获得了较高的响应特性和跟踪精度.通过理论分析和仿真实验说明了该方法的有效性和可行性.     

基于滑模反演的欠驱动水面无人艇航向控制

欠驱动无人艇作为一种水上重要的工作平台,其应用范围非常广泛。针对一种欠驱动水面无人艇的运动控制进行研究,首先分别建立其运动学和考虑了风浪干扰的动力学模型,得出了非线性状态空间模型;然后采用基于指数滑模面的滑模和反演相结合的控制算法设计其航向控制器;最后通过仿真和实物实验验证了设计的动力学方程和控制算法的有效性。     

平行单级双倒立摆基于滑模的稳定控制

平行单级双倒立摆相对单级倒立摆、二级倒立摆而言是非线性更强、耦合作用更复杂的不稳定欠驱动系统,从而控制难度更大。本文针对俩摆间无弹簧的平行单级双倒立摆设计了滑模变结构控制律,仿真结果显示该控制律对外部干扰和内部参数变化都有很强的鲁棒性。