移动机械手的跟踪控制

讨论一类不确定非完整移动机械手的跟踪控制问题。在系统惯性参数不精确知道的情况下,提出一种鲁棒控制器。为提高跟踪性能,进一步设计出使跟踪误差指数收敛的控制器。计算机仿真验证了所提出控制律的有效性。     

基于神经动力学的非完整移动机器人跟踪控制

主要研究了非完整移动机器人轨迹跟踪问题。基于后退控制和神经动力学生物激励模型,采用自适应参数调节的方法提出了一种新的跟踪控制器。该控制器能够生成平稳合理的速度,解决了以往大部分跟踪控制器所产生的速度突变问题,并且具有很好的鲁棒性。运用李雅普诺夫稳定性理论证明控制系统的稳定性。对连续、离散轨迹的仿真及与传统后退方法的比较分析验证了该方法的有效性。     

Adaptive Trajectory Tracking Control for Nonholonomic Wheeled Mobile Robots:A Barrier Function Sliding Mode Approach

The trajectory tracking control performance of nonholonomic wheeled mobile robots(NWMRs) is subject to nonholonomic constraints, system uncertainties, and external disturbances. This paper proposes a barrier function-based adaptive sliding mode control(BFASMC) method to provide high-precision, fast-response performance and robustness for NWMRs.Compared with the conventional adaptive sliding mode control,the proposed control strategy can guarantee that the sliding mode variables converge to a pre...     

具有未知视觉参数的非完整移动机器人的自适应动态反馈跟踪控制

基于视觉反馈和标准链式形式,研究了一类不确定非完整移动机器人的轨迹跟踪控制问题.首先,利用针孔摄像机模型,提出了一种新的基于视觉伺服的移动机器人运动学跟踪误差模型.基于这个模型,在具有不确定视觉参数的情形下,利用back-stepping技术,设计出了一种新的自适应动态反馈跟踪控制器,实现了全局渐近的轨迹跟踪,并通过李亚普诺夫方法严格证明了闭环系统的稳定性和估计参数的有界性.仿真结果证明了所提出的控制器的有效性.     

轮式移动焊接机器人弯曲焊缝跟踪控制

分析了轮式移动焊接机器人弯曲焊缝轨迹跟踪问题,建立了机器人的数学模型,采用基于积分backstepping时变状态反馈方法设计了控制器,利用Laypunov方法证明系统是镇定的。针对旋转电弧传感器仅能检测单方向偏差的情况,根据焊枪前端上一时刻和当前时刻的位置对跟踪轨迹的方位角进行估计。控制器在对机器人速度和角速度控制的同时,还对十字滑块进行了控制,使跟踪更加快速、平滑。最后通过数值仿真和机器人实际运动仿真证明了该方法的有效性。     

非完整移动机械手鲁棒自适应模糊控制

考虑系统存在的参数、外界扰动和未建模动态等不确定性,研究非完整移动机械手的鲁棒自适应控制器设计方法.基于用旋量理论建立的非完整移动机械手的动力学模型,设计了移动平台子系统的运动控制器,然后应用非线性反步控制技术和模糊逻辑系统的通用逼近性,用参数化线性模糊逻辑系统逼近非完整移动机械手动力学模型中的不确定项,基于Lyapu...     

基于Haar小波分解的轮式移动机器人轨迹跟踪控制

利用Haar小波在满足机器人动力学约束的前提下 ,对期望轨迹进行曲线分解 ,得到所需的一系列参考点 ,并由这些参考点构造出虚拟小车的运动轨迹 .基于控制Lyapunov函数设计了速度跟踪控制律 ,驱动机器人跟随虚拟小车实现对期望轨迹的跟踪 .该方法的突出特点是可实现对任意复杂轨迹的跟踪控制 ,且不存在速度跳跃点 .仿真实验结果表明它的有效性 .     

Motion Control of a Nonholonomic Mobile Manipulator in Task Space

In this paper, the motion control of a mobile manipulator subjected to nonholonomic constraints is investigated. The control objective is to design a computed‐torque controller based on the coupled dynamics of the mobile manipulator. The proposed controller achieves the capability of simultaneous tracking of a reference velocity for the mobile base and a reference trajectory for the end‐effector. The aforementioned reference velocity and trajectory are defined in the task space, such task setting imitates the actual working conditions of a mobile manipulator and thus makes the control problem practical. To solve this tracking problem, a steering velocity is firstly designed based on the first‐order kinematic model of the nonholonomic mobile base via dynamic feedback linearization. The main merit of the proposed steering velocity design is that it directly utilizes the reference velocity set in the task space without requiring the knowledge of a reference orientation. A torque controller is subsequently developed based on a proposed Lyapunov function which explicitly considers the coupled dynamics of the mobile manipulator to ensure the mobile base and end‐effector track the reference velocity and trajectory respectively. This proposed computed‐torque controller is able to realize asymptotic stability of both the base velocity tracking error and the end‐effector motion tracking error. Simulations are conducted to demonstrate the effectiveness of the proposed controller.     

A Smooth Path Tracking Algorithm for Wheeled Mobile Robots with Dynamic Constraints

In order to avoid wheel slippage or mechanical damage during the mobile robot navigation, it is necessary tosmoothly change driving velocity or direction of the mobile robot. This means that dynamic constraints of the mobile robotshould be considered in the design of path tracking algorithm. In the study, a path tracking problem is formulated asfollowing a virtual target vehicle which is assumed to move exactly along the path with specified velocity. The drivingvelocity control law is designed basing on bang-bang control considering the acceleration bounds of driving wheels. Thesteering control law is designed by combining the bang-bang control with an intermediate path called the landing curve whichguides the robot to smoothly land on the virtual target's tangential line. The curvature and convergence analyses providesufficient stability conditions for the proposed path tracking controller. A series of path tracking simulations and experimentsconducted for a two-wheel driven mobile robot show the validity of the proposed algorithm.     

Robust Tracking Control For A Wheeled Mobile Manipulator With Dual Arms Using Hybrid Sliding‐Mode Neural Network

In this paper, a robust tracking controller is proposed for the trajectory tracking problem of a dual‐arm wheeled mobile manipulator subject to some modeling uncertainties and external disturbances. Based on backstepping techniques, the design procedure is divided into two levels. In the kinematic level, the auxiliary velocity commands for each subsystem are first presented. A sliding‐mode equivalent controller, composed of neural network control, robust scheme and proportional control, is constructed in the dynamic level to deal with the dynamic effect. To deal with inadequate modeling and parameter uncertainties, the neural network controller is used to mimic the sliding‐mode equivalent control law; the robust controller is designed to compensate for the approximation error and to incorporate the system dynamics into the sliding manifold. The proportional controller is added to improve the system's transient performance, which may be degraded by the neural network's random initialization. All the parameter adjustment rules for the proposed controller are derived from the Lyapunov stability theory and e‐modification such that uniform ultimate boundedness (UUB) can be assured. A comparative simulation study with different controllers is included to illustrate the effectiveness of the proposed method.     

基于自适应反步法的轮式移动机器人跟踪控制

轮式移动机器人是一种典型的非完整约束系统.基于反步法提出一种自适应扩展控制器,对含有未知参数的非完整轮式移动机器人动力学系统进行轨迹跟踪控制并且Lyapunov稳定性理论保证跟踪误差渐近收敛到零.为了克服速度跳变产生滑动,加入了神经动力学模型对控制器进行改进.以两驱动轮移动机器人为例,利用运动学自适应控制器设计出转矩控制器,有效解决了不确定非完整轮式移动机器人动力学系统的轨迹跟踪问题.仿真结果证明该方法的正确性和有效性.     

基于动力学模型的轮式移动机器人电机控制

针对移动机器人两路电机协同控制问题,提出基于动力学模型的轮式移动机器人电机控制律 （DMMC）．首先推导出质心位置不一定在几何中心的移动机器人运动学模型和动力学模型,并求解出两轮速 度与力矩之间的非线性微分方程．然后,基于两轮速度与力矩间非线性微分方程、电机电气方程和电机机电 方程,推导出移动机器人系统状态方程．最后采用极点配置得到I 型状态反馈控制律．仿真显示,DMMC 法实 现了对输入指令的零稳态误差快速响应．     

非完整约束移动机器人的轨迹跟踪控制

针对非完整约束移动机器人运动学与动力学模型,根据轨迹跟踪控制目标的需要,设计了一种简单的控制器,该控制器结合了运动学控制器设和动力学控制器两部分;针对运动学模型,采用自适应算法对其未知参数进行估计,针对系统动力学模型,采用单层神经网络算法克服未知扰动对系统稳定性的影响,使速度误差尽可能地缩小;在Lyapunov稳定性理论的基础上证明了系统的收敛性和稳定性,该控制算法简单有效,易于实现;仿真结果表明:该控制策略可以实现对移动机器人期望轨迹的稳定跟踪,验证了算法的有效性。     

基于Lyapunov稳定性理论的移动机器人轨迹跟踪控制

针对非完整轮式移动机器人的高度强耦合、欠驱动非线性动力学模型,设计了运动学控制器以及动力学力矩控制器,使得移动机器人轨迹能够跟踪理想轨迹.这种方法的实质是首先设计虚拟速度控制器,输出速度的期望值,然后设计基于模型的力矩控制器.最后通过simulink软件对所设计的系统进行仿真,结果表明对于非完整机器人的轨迹跟踪这种控制...     

An Adaptive Coverage Control for Deployment of Nonholonomic Mobile Sensor Networks Over Time‐Varying Sensory Functions

In this paper we show the Lyapunov stability of an adaptive and decentralized coverage control for a team of mobile sensors. This new coverage approach assumes nonholonomic sensors rather than the holonomic ones usually found in the literature. Furthermore, sufficient conditions are provided to guarantee an ultimate bound for the system when in presence of time‐varying sensory functions. The convergence and feasibility of the coverage control are verified through simulation and experimental results.     

Dynamic Analysis of a Nonholonomic Two-Wheeled Inverted Pendulum Robot

As a result of the increase in robots in various fields, the mechanical stability of specific robots has become an important subject of research. This study is concerned with the development of a two-wheeled inverted pendulum robot that can be applied to an intelligent, mobile home robot. This kind of robotic mechanism has an innately clumsy motion for stabilizing the robot's body posture. To analyze and execute this robotic mechanism, we investigated the exact dynamics of the mechanism with the aid of 3-DOF modeling. By using the governing equations of motion, we analyzed important issues in the dynamics of a situation with an inclined surface and also the effect of the turning motion on the stability of the robot. For the experiments, the mechanical robot was constructed with various sensors. Its application to a two-dimensional floor environment was confirmed by experiments on factors such as balancing, rectilinear motion, and spinning motion.     

一类不确定非完整机器人的时变自适应镇定

通过对质心和几何中心不重合情况下两轮驱动移动机器人镇定问题的研究，提出了一种光滑时变控制律，并针对质心和几何中心距离参数未知的情况，利用自适应技术对其进行了修正. 证明了所提出的控制律可使该类型移动机器人的位姿从任意的初始状态指数收敛到原点．仿真试验验证了本文所提出控制律的有效性．     

Nonlinear Control of a Robot Manipulator with a Nonholonomic Jerk Constraint

We study the control of a prismatic‐prismatic‐revolute (PPR) robot manipulator subject to a nonholonomic jerk constraint, i.e., a third‐order nonintegrable design constraint. The mathematical model is obtained using the method of Lagrange multipliers. The control inputs are two forces and a torque applied to the prismatic joints and the revolute joint, respectively. The control objective is to control the robot end‐effector movement while keeping the transverse jerk component as zero. The main result of the paper is the construction of a feedback control algorithm that transfers the manipulator from any initial equilibrium configuration to the zero equilibrium configuration in finite time. The effectiveness of the algorithm is illustrated through a simulation example.     

一类非完整移动机器人编队控制方法

针对大部分两轮非完整移动机器人轮轴中心与几何中心不重合的特点, 提出一种多机器人协调编队控制算法. 构造队形参数矩阵确定编队形状, 根据领航机器人和相关队形参数生成虚拟机器人, 把编队控制分解为跟随机器人对虚拟机器人的轨迹跟踪. 建立虚拟机器人与跟随机器人之间误差系统模型, 利用Lyapunov 理论设计相应控制器, 从而实现队形保持和变换. 应用microsoft robotics developer studio 4(MRDS4) 搭建3D 仿真平台, 设计3 组实验, 结果进一步验证了所提出方法的有效性.

     

一类不确定非完整动力学系统的鲁棒镇定*

研究了一类不确定非完整动力系统的鲁棒镇定问题,设计了时变镇定律,仿真表明了该镇定律有效性。