3-DOF并联拟人肩鲁棒自适应控制

针对一类3-DOF球面并联拟人肩的轨迹跟踪问题,提出一种鲁棒自适应算法.考虑系统中存在的参数不确定性和外部扰动,利用该模型的参数性质,由集中不确定性描述此机构的参数不确定性和外部扰动,并证明了集中不确定性范数有界.该控制器通过自适应算法在线学习集中不确定性的上界参数,进而实时补偿了由参数不确定性及干扰引起的误差,避免了参数过于保守而导致的控制器饱和,保证了系统的全局指数稳定.严格的证明和仿真结果验证了此算法的有效性.     

基于无源化方法的移动机器人轨迹跟踪控制

该文将无源化方法应用到机器人轨迹跟踪控制中,根据机器人的动力学模型,采用基于模型及其转换矩阵的时变误差反馈的控制策略,将机器人的动力学过程转变为一个无损系统和关于一个二维向量的无源性映射。构造一个严格输入无源反馈映射,则此闭环系统为严格输出无源的,即此二维向量输出属于L2^n空间。由无源系统输出与轨迹跟踪误差间的转换矩阵形式可知跟踪误差也属于L2^n空间,即轨迹跟踪系统是稳定的。仿真结果表明,此方法控制效果良好,可以无差跟踪任意轨迹。     

一类未知参数非线性系统的自适应无源控制

对一类含有未知参数的本质非线性系统,通常的Backstepping方法无法应用.为此,提出一种基于状态反馈的自适应无源控制对策,通过对非线性系统进行反馈无源化控制,设计自适应无源镇定控制器和自适应无源输出跟踪控制器.设计中适当调节自适应无源控制器参数,能够保证闭环系统稳定且所有信号全局一致有界,从而解决了此类含有未知参数非线性系统的稳定性和输出跟踪问题.仿真算例验证了提出控制方案的有效性,表明系统具有较强的稳定性和跟踪特性.     

具有未校准视觉参数的移动机器人的跟踪控制

基于未校准视觉反馈的非完整运动学系统具有参数不确定性,较一般的运动学系统更加复杂.根据视觉反馈和非完整移动机器人的链式标准形式,研究了具有未标定摄像机视觉参数的移动机器人的轨迹跟踪控制问题.利用固定在天花板上的摄像机系统提出运动学跟踪误差模型,并对该误差系统模型提出了一种动态反馈跟踪控制器;对具有不确定机械参数的动力学模型,提出一种自适应力矩控制器,该控制器保证了实际机器人状态渐近跟踪给定的参考轨迹,并通过Lyapunov方法严格证明了整个闭环系统的稳定性.仿真结果证实了所提出的控制器的有效性.     

拟人机器人关节空间自适应H_∞位置跟踪控制

拟人机器人的建模和控制一直是一种开放的、富于挑战性的问题,研究了一种正交轮式移动车为载体的拟人机器人控制问题。首先建立了系统模型,据此提出一种新的基于NN的自适应H∞位置跟踪控制器,将鲁棒非线性H$控制方法与模型的直接自适应神经网络技术作了自然集成。然后证明了其鲁棒稳定性,并进一步分析了控制器中的重要细节。最后仿真研究验证了该控制器的正确性和有效性。     

基于无源性的全方位移动机器人自抗扰控制

针对全方位移动机器人轨迹跟踪控制中存在的外界干扰和系统参数不确定性问题,提出基于无源性的自抗扰控制方法.该方法通过扩张状态观测器对系统扰动进行估计,并在基于无源性的控制器中加入扰动补偿项以减小外界干扰和参数不确定性对系统的影响;进而,利用系统的无源特性和Lyapunov 理论证明在该控制器作用下闭环系统有界输入有界输出稳定.仿真结果表明,所提出的控制方法响应速度较快,控制精度较高,对系统外扰和模型参数不确定性具有较强的鲁棒性     

考虑状态约束与执行器饱和的水下机器人轨迹跟踪控制

针对执行器饱和、模型参数不确定以及海流干扰等因素影响下的水下机器人,提出一种考虑状态约束以及执行器饱和的轨迹跟踪控制器.首先,构建水下机器人水平面轨迹跟踪误差方程;然后,对载体模型参数不确定性产生的模型误差以及海流干扰,设计一个非线性观测器进行估计并用于对控制器进行扰动补偿;接着,引入执行器饱和补偿系统、二阶滤波器以及滤波器误差补偿系统,设计命令滤波反步滑模控制器来控制水下机器人的水平面轨迹跟踪;最后,严格验证命令滤波反步滑模控制器的稳定性并进行数值仿真,验证所提出控制器的有效性.     

基于无模型自适应控制的视觉伺服

传统的机器人视觉伺服控制技术需要已知机器人精确的动力学和运动学模型以及机器人的手-眼参数。然而,由于机器人建模、手-眼标定等过程存在一定误差,因此很难精确获得视觉伺服控制模型,从而影响机器人视觉伺服系统的精度和收敛速度。针对这一难题,本文提出一种基于无模型自适应控制方法（MFAC）的机器人视觉伺服技术。利用视觉伺服系统的输入与输出数据,实现自适应视觉伺服控制,即通过MFAC在线估计机器人伺服控制器中的雅各比矩阵,并结合滑模控制器,实现机器人对目标的快速精确跟踪。实验结果表明,本文提出的方法在系统参数变化引起的未知扰动情况下仍能保证伺服控制器平稳收敛,并且能够减小视觉跟踪误差。     

感应电机转矩跟踪无源控制及自适应观测器设计

针对感应电机高性能转矩跟踪控制和磁链难以直接测量问题,提出了基于无源性的转矩跟踪和自适应磁链观测器控制方案.首先基于感应电机的无源性特性设计了渐近稳定转矩跟踪控制器,重新配置了系统的平衡点,通过注入阻尼提高系统的收敛速度.然后通过将定子电流和转子磁链作为状态变量构建了自适应磁链观测器,简化了观测器结构,根据Lyapunov稳定性理论设计了自适应控制律,实现转子磁链、转速和定子电阻的在线估计.为减小转速估计误差对观测器的影响,给出了观测器增益矩阵的选择方法.仿真结果表明本文所提出的基于自适应观测器的无源控制方案能够有效提高感应电机的动静态性能.     

矩阵变换器输入侧端口受控耗散哈密尔顿算子建模及无源控制

矩阵变换器无中间直流环节,易受电网扰动和负载扰动的影响.针对这一问题,本文设计了矩阵变换器输入侧无源性控制器以改善控制系统特性.首先,在直–交坐标系下建立输入侧的端口受控耗散哈密尔顿(port-controlled Hamiltonian with dissipation,PCHD)算子模型.然后,设计了基于互联和阻尼配置的无源性控制器,用来实现对输入电流快速准确的跟踪.重新配置了系统的平衡点,通过注入阻尼提高系统的收敛速度,并从理论上对闭环系统的渐进稳定性进行了分析.仿真结果表明,系统在非正常工况下仍能保证输入电流为正弦,相比传统偏差修正法,该控制策略具有更好的动态性能和抗干扰能力.     

A novel power line inspection robot with dual-parallelogram architecture and its vibration suppression control

Developing a climbing robot to inspect the power transmission line is a state-of-the-art method. To enhance the obstacle-crossing ability, a novel tri-arm robot with dual-parallelogram architecture (DPA) is developed. The DPA can improve the efficiency to move each arm in 3D space, keep the force on each arm well balanced, and enhance the adjacent-obstacle-crossing ability. Besides that, the centroid of the payload can shift in a large range which could greatly decrease the motor load. The dynamic model of the robot considering the floating base effect and link elastic distortion is constructed, based on which a state feedback controller is proposed to suppress the system vibration caused by the link dynamic coupling, link elastic distortion and external disturbance. A linear matrix inequality-based regional pole placement method is introduced to tune the state feedback gains, and an empirical parameter regulation strategy is employed to compensate the model parameter inaccuracy and state estimation error. Both simulation and real robot experiment results verify the effectiveness of the proposed method for system vibration suppression. The experiments on the prototype robot verify the feasibility of the designed mechanism.     

基于能量的蛇形机器人蜿蜒运动控制方法的仿真与实验研究

能量作为最基本的物理量之一, 联系着蛇形机器人蜿蜒运动的各个方面. 能量耗散描述了环境交互作用, 能量转换对应着运动的动力学过程, 能量平衡反映了蜿蜒运动的协调性. 提出一种基于能量的蛇形机器人蜿蜒运动控制方法-被动蜿蜒. 通过输出关节力矩控制机器人蜿蜒运动, 由机器人的能量状态调整力矩的大小. 仿真结果显示了被动蜿蜒控制下机器人的构形、角度、力矩、能量状态和转弯特性, 并对控制力矩进行了递归分析. 基于Optotrak运动测量系统构建了被动蜿蜒控制的模拟/物理混合实验系统. 进行了移动实验和拖动实验, 前者改变环境的摩擦特性,后者改变机器人的负载. 仿真和实验验证了蛇形机器人被动蜿蜒控制的有效性和适应性.     

正弦驱动与传感反馈结合的双足机器人仿生行走控制

提出了一种正弦驱动与传感反馈结合的双足机器人仿生行走控制方法．所有关节由正弦振荡器驱动, 较之相互耦合的神经元振荡器更加简单;控制参数具有明晰的物理意义,便于对运动模式进行调节．传感反馈表征 了机器人的运动状态,对于保证机器人的稳定行走起着至关重要的作用．将机器人碰地、碰膝等关键运动状态作为 相位反馈,对控制力矩进行相位重置,协调各关节动作,进而实现控制器、机器人、环境的耦合．同时,从节省能量 和仿生的角度,考虑了关节运动的被动特性,确定了各关节力矩的作用区间．仿真结果表明,该控制方法能实现机 器人稳定行走,并具有良好的能效性和自稳定性.     

一般7R串联机器人标定的仿真与实验

为了标定一般7R冗余度串联机器人的所有几何参数,提出了一种实效的算法．首先,使用D-H矩阵对机器人建立了运动学模型和几何参数识别模型,对雅可比矩阵进行奇异值分解并对分解后的正交阵的最后5行进行初等行变换,以确定需要补偿的几何参数．通过机器人关节角和末端手爪位置的测量数据,计算雅可比矩阵以及手爪位置理论值和实测值的误差,采用最小二乘法对机器人的尺寸参数进行补偿量的计算．仿真过程表明,在有测量扰动的情况下,算法是稳定的和可靠的．最后,对机器人进行了实际的测量和标定,取得了满意的结果．     

On the Complete Coverage Path Planning for Mobile Robots

This paper presents a generalized complete coverage path planning (CCPP) algorithm and its implementation for a mobile robot. The proposed planner contains two concerns: 1) low working time or low energy consumption, and 2) high human safety. For the first concern, we design the optimal path by incorporating two factors: time and energy costs. Describing the working time and energy in terms of a turning parameter simplifies the optimal path design either for minimizing the time or energy cost. For obstacle avoidance in the CCPP, fixed or moving objects are avoided by proposing a field method describing the effects of factors such as working dangerousness and difficulty on the current robot navigation. The human safety is simultaneously guaranteed by this method. Furthermore, a backstepping controller considering constraints imposed on the control input is established to track the optimal route. An implementation of the proposed CCPP for the experimentally mobile robot equipped with this controller is presented; the verification results demonstrate significant performance and practicality of the proposed strategy.     

Development and motion control of a biped walking robot based on passive walking theory

This research aims to develop the biped walking robot that can walk on the horizontal ground and improve walking efficiency by utilizing the theory of the passive walking robot, namely the pendulum principle. For that, two motors were installed on the hip of the robot to generate the control torques to perform a walking motion. The computer simulations with dynamic model were carried out to investigate the walking capability of the system. Experimental robot was developed considering the calculated results. The proportional control law was used in walking experiment. The robot can walk on the horizontal ground with the proposed method.     

Estimation model for kinematic calibration of manipulators with a parallel structure

This article provides an estimation model for calibrating the kinematics of manipulators with a parallel geometrical structure. Parameter estimation for serial link manipulators is well developed, but fail for most structures with parallel actuators, because the forward kinematics is usually not analytically available for these. We extend parameter estimation to such parallel structures by developing an estimation method where errors in kinematical parameters are linearly related to errors in the tool pose, expressed through the inverse kinematics, which is usually well known. The method is based on the work done to calibrate the MultiCraft robot. This robot has five linear actuators built in parallel around a passive serial arm, thus making up a two-layered parallel-serial manipulator, and the unique MultiCraft construction is reviewed. Due to the passive serial arm, for this robot conventional serial calibration must be combined with estimation of the parameters in the parallel actuator structure. The developed kinematic calibration method is verified through simulations with realistic data and real robot kinematics, taking the MultiCraft manipulator as the case. © 1994 John Wiley & Sons, Inc.     

考虑关节柔性的模块机器人动力学参数辨识

提出了一种基于3维运动测量系统Optotrak3020的柔性关节模块机器人动力学模型参数辨识方法.首先将机器人的动力学模型参数化为不包括刚度力矩的线性形式,避免了参数矩阵的标定问题.激励轨迹基于有限的傅里叶级数函数,采用自适应遗传算法得出了优化的傅里叶级数系数.机器人每一关节单独跟随优化激励轨迹进行运动,同时电机位置、...     

Energy-Optimal Design of Walking Machines

In a general definition of robot components given by Wolfram Stadler, communications and power supply are included showing the close relation between robots and walking machines. Both of them are based on mechatronics allowing variable programmable operations.Biped walking represents a complex motion of sophisticated systems in nature as well as in engineering. A young human requires more than 1 year to learn walking while old humans need additional devices for save walking. While passive machines walk only on inclined planes, active machines may walk in all kinds of terrains. However, the active devices known from literature consume so much energy that their operation time is very restricted.In this paper the modeling of walking systems using the method of multibody dynamics is presented including the contact and impact problem inherent to biped walking. The limit cycle of passive motions is investigated as well as the related stability using shooting approaches with optimization techniques. The active machines proposed are controlled using the principles of inverse dynamics and advanced linear control strategies. In particular, the energy consumption between passive and active walking machines is compared by a coefficient of efficiency. At the time being human walking is still the most efficient and it is considered as a benchmark for the mechatronic design of walking machines.     

Distributed structural dynamics control of flexible manipulators —I. Structural dynamics and distributed viscoelastic actuator

Reducing structural dead weight has become of increasing importance in the design of new generation lightweight and high-speed robot manipulators. However, due to the nature of structural flexibility, the dynamic oscillation associated with robot structures can affect the operation accuracy and precision. This work, in two parts, presents a study on the vibration control of elastic or flexible robot structures. Effects of distributed passive (Part I) and active (in Part II) actuators on elastic robot structures are studied. The proposed distributed passive viscoelastic actuator (in Part I) is a layer (or layers) of viscoelastic polymer directly attached to the flexible robot element, the oscillation of which is to be controlled. The passive actuator is activated by the oscillation of the robot structure and it automatically dissipates vibration energy and constrains the undesirable motion to eliminate the disturbance and to maintain a precise robot trajectory. A finite element program capable of analyzing flexible links is developed. Results obtained from the finite element simulation are presented.