移动机器人计算机控制

根据移动机器人跟踪控制和运动规划的目的,设计了一套计算机控制系统,其中包括计算机控制部分、直流伺服电机驱动部分、视觉系统部分和电机转向分辨电路部分,以及控制程序设计流程。该系统的硬件和软件能够有效快速驱动移动机器人跟踪预定的路径以及完成运动规划。     

三轮全方位移动机器人运动模型及其控制方法研究

全方位移动机器人在二维空间具有完整性约束条件,能够灵活地任意方向移动,受到了广泛的关注。针对三轮全方位机器人的运动控制问题,建立其运动学模型。采用输入变换解耦及状态反馈法实现对坐标位置、方位角等位姿状态的控制,通过仿真实验验证了算法的有效性。最后给出了一种三轮全方位移动机器人硬件设计方案及控制算法软件实现,实际样机运动实验验证了控制方法的可行性与有效性。     

Variable Structure Control of a Differentially Steered Wheeled Mobile Robot

This paper discusses dynamic modeling and robust control of a differentially steered mobile robot subject to wheel slip and external loads. Consideration of wheel slip and external loads is crucial for high load and/or high speed applications because they act as disturbances to the system. Furthermore, a tire model that adequately accounts for the tire/ground interaction is essential and Dugoff's pneumatic tire friction model is utilized herein in deriving the dynamic equations of motion of the mobile robot. It is shown that the dynamic equations satisfy the matching condition, and the variable structure control method is employed to design a tracking controller of the mobile robot. Numerical simulation shows the promise of the developed control algorithm.     

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.     

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。     

Trajectory Tracking Control of Nonholonomic Wheeled Mobile Robots Using Model Predictive Control Subjected to Lyapunov-based Input Constraints

International Journal of Control, Automation and Systems - This paper studies the trajectory tracking control for the nonholonomic wheeled mobile robot (WMR) based on model predictive control...     

轮式移动机器人曲线行走控制的实现

从实用的角度出发,对轮式移动机器人沿曲线轨迹行走的控制进行了研究。设计了电机伺服控制系统和定位模块来实现机器人的运动控制系统功能,并基于移动机器人动力学模型设计了稳定有效的曲线行走控制算法。机器人沿抛物线和椭圆轨迹行走的实验结果表明,移动机器人曲线行走控制的硬件结构和软件功能是可行实用的,该户外轮式移动机器人运动控制系统的结构设计和功能设计符合实用要求,具有一定的应用价值。     

轮式移动机器人预见预测运动控制

针对移动机器人的运动控制问题,该文采用预见预测控制方法加以解决。利用三阶Bezier曲线作为路径生成器生成目标轨迹,并据此设计了最优预见控制器作为系统的前馈补偿;使用扩展卡尔曼滤波器作为预测模型,基于广义预测控制(GPC)实现了PPC运动控制器的设计。仿真实验结果证明了该方法的有效性。     

轮式移动机器人智能变结构控制算法研究

针对参数摄动和存在外部扰动的轮式移动机器人的运动控制问题,设计一种多模态控制和模糊PID控制可相互切换的智能变结构控制器.从轮式移动机器人的运动学特性出发,根据轮式移动机器人误差的状况,提出多模态控制和模糊PID控制相结合的控制方法.同时,多模态控制按照误差的变化情况来划分控制模态,是一种更加合理地模仿人思维的控制方法.仿真结果表明,与传统的PID和模糊PID控制方法相比,能较好地弥补了系统参数摄动的影响,提高了机器人运动控制品质.     

农用轮式移动机器人相对位姿的求解方法

在基于单目视觉的自主导航中，由于农用轮式移动机器人相对于跟踪路径位姿的传统求解算法，往往存在忽视图像中各像素点权重不同和计算效率不理想等缺陷，因此，针对农田环境特点，在分析地面上直线路径透视成像特性的基础上，提出了一种农用轮式移动机器人相对位姿的求解方法。该方法首先建立起被跟踪路径在图像平面上的像素坐标与机器人相对位姿间的关系方程，然后结合Hough变换的思想直接求出位姿值。实验结果表明，该方法不仅可以有效地弥补传统算法的不足，而且测量精度也与当前其他类似研究的水平大致相当。     

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 .     

基于预测控制的全向移动机器人轨迹跟踪

针对全向移动机器人的轨迹跟踪控制问题,在分析与建立全向移动机器人运动学与动力学模型的基础上,研究了基于模型预测控制的移动机器人轨迹跟踪方法;通过对误差模型的线性化描述,并将目标函数以二次项部分与线性部分构成,在满足控制约束的条件下,将采样周期内最小化目标甬数的优化问题转换为二次规划问题的求解;当取预测时域N=5时,机器人在x和y方向的误差范围分别为±5.4%和±4.7%,并在轨迹曲线中曲率半径较小处出现较为明显的抖动,最后对误差产生原因进行了分析与总结,结果表明该方法对全向移动机器人的轨迹跟踪控制是有效可行的.     

一处室内轮式自主移动机器人的导航控制研究

介绍了一种室内移动机器人CASIA-I.对该机器人的运动机构做了较为详细地阐述,针对该运动机构给出了机器人的运动方程和一种导航控制算法,并根据该算法进行了软件仿真和实物实验.在软件仿真和实物实验两种环境下,机器人都能够实时避开障碍物奔向目标.仿真和实验表明:该移动平台具有良好的可靠性,且该导航控制算法是一种有效的导航算法.     

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．     

EKF-Based Localization of a Wheeled Mobile Robot in Structured Environments

This paper deals with the problem of mobile-robot localization in structured environments. The extended Kalman filter (EKF) is used to localize the four-wheeled mobile robot equipped with encoders for the wheels and a laser-range-finder (LRF) sensor. The LRF is used to scan the environment, which is described with line segments. A prediction step is performed by simulating the kinematic model of the robot. In the input noise covariance matrix of the EKF the standard deviation of each robot-wheel’s angular speed is estimated as being proportional to the wheel’s angular speed. A correction step is performed by minimizing the difference between the matched line segments from the local and global maps. If the overlapping rate between the most similar local and global line segments is below the threshold, the line segments are paired. The line parameters’ covariances, which arise from the LRF’s distance-measurement error, comprise the output noise covariance matrix of the EKF. The covariances are estimated with the method of classic least squares (LSQ). The performance of this method is tested within the localization experiment in an indoor structured environment. The good localization results prove the applicability of the method resulting from the classic LSQ for the purpose of an EKF-based localization of a mobile robot.     

A Stable Switched-System Approach to Collision-Free Wheeled Mobile Robot Navigation

This paper presents a novel switched-system approach for obstacle avoidance by mobile robots. This approach does not suffer from common drawbacks of existing methods, such as needing prior knowledge of obstacles, or local minima or chattering in control laws. We define an attractive and an avoidance vector in obstacle-free and obstacle-avoidance regions, respectively. Next, we define an unified velocity vector, which represents either the attractive vector or the avoidance vector, and drives the robot away from the obstacle and ultimately towards the goal. The avoidance vector differs from the repulsive vector commonly used in potential field approaches, rather it is defined always perpendicular to such a repulsive vector and projects positively onto the attractive vector. The unified velocity vector enables the use of a common Lyapunov function in analyzing the stability of the system under arbitrary switching. Novel switching rules are proposed for obstacles that can be well bounded by a circle in the local subset of SE(2). To better handle large, non-circular obstacles, a separate switching signal is proposed. Through the choice of switching rule, we investigate the chattering problem that can hinder some switching controllers. We present two control laws, one with bounded inputs and one with no bounds on inputs. We prove both control schemes are asymptotically stable and guide the robot to the goal while avoiding obstacles. To verify the effectiveness of the proposed approach, as well as compare the control laws and switching rules, several simulations and experiments have been conducted.     

Disturbance Observer-Based Trajectory Tracking Control for Nonholonomic Wheeled Mobile Robot Subject to Saturated Velocity Constraint

The problem of trajectory tracking control for a nonholonomic mobile robot is discussed in this study, in which both the dynamic behaviors of disturbance adaptability and the velocity saturation constraint are considered simultaneously. To realize this objective, a double closed-loop control structure is presented. On the outer loop, an improved velocity saturated controller based on hyperbolic tangent function is established; on the inner loop, an integral sliding mode controller, which possesses a fast transient response property with less steady-state error, is developed. In addition, to alleviate the inherent chattering behavior of sliding mode technology and enhance the external disturbance adaptability, an adaptive scheme as a disturbance observer is adopted by which one could estimate the uncertain disturbance acting on the mobile wheels rapidly. Simulation results verify the effectiveness of the proposed control theories.     

一维云模型控制器在轮式机器人中的应用

云模型控制理论是智能控制学科的新兴领域,该理论从提出至今,主要以理论研究和仿真实验为主.针对云模型理论的研究现状,提出了基于单片机的一维云模型控制器的设计方法,应用该方法设计的云模型控制器成功地对轮式机器人进行了实时定位控制.实验结果表明,一维云模型控制器可以保证轮式机器人定位系统具有良好的控制性能和较强的干扰性,证明了该设计的有效性和科学性,为今后云模型控制器设计提供了一定的参考.     

Adaptive Motion Control of a Mobile Wheeled Robot Taking into Account the Nonideality of the Drives

Journal of Computer and Systems Sciences International - A method of mathematical modeling is used to study the controlled motion of a wheeled mobile robot in the presence of parametric...