移动送料机器人地图构建与运动控制研究

移动机器人的地图构建与运动控制是智能移动机器人进行自主导航的基础.针对工业装配生产线的不同工位需要送料的需求,本文以一台轮式差速移动送料机器人为研究对象,利用激光雷达作为传感器,搭建一个装配生产线,设计、实现了基于ROS的移动送料机器人的地图构建与运动控制策略.利用slam_gmapping算法包,实现了机器人在特定装...     

Design and implementation of an adaptive sliding-mode dynamic controller for wheeled mobile robots

This paper designs an adaptive sliding-mode dynamic controller for wheeled mobile robots to implement the trajectory-tracking mission. First, a kinematic controller is introduced for the wheeled mobile robot. Secondly, the adaptive sliding-mode dynamic controller is proposed to make the real velocity of the wheeled mobile robot reach the desired velocity command, although the wheeled mobile robot is even with system uncertainties and disturbances. The convergence of the complete equations of motion of the wheeled mobile robot is proved by the Lyapunov stability theory. Computer simulation results illustrate the effectiveness of the proposed control schemes. Finally, the real-time experiments of the adaptive sliding-mode dynamic controller on the test ground demonstrate the feasibility of practical wheeled mobile robot maneuvers.     

Generalized proportional integral observer based control of an omnidirectional mobile robot

This paper presents an observer based trajectory tracking control system design for an omnidirectional mobile robot with MY wheel-II. MY wheel-II is a switch wheel mechanism. Switch wheeled omnidirectional mobile robots are complicated autonomous switched nonlinear systems. In this paper, the complicated switching dynamics, unmodeled dynamics and input–output cross-couplings are considered as an unknown time-varying perturbation input vector, which is online estimated by means of a generalized proportional integral observer. The original switched nonlinear multi-input multi-output system is then reduced to three decoupled double integrators in an approximate manner. Traditional proportional derivative controllers are then applied to the decoupled double integrators. In addition, only part of the robot model information is used in the control system design. Simulation and experimental tests illustrate the effectiveness of this practical control method.     

轮式机器人滑模轨迹跟踪控制器设计

轮式机器人是一个典型的非完整性系统。由于非线性和非完整特性,很难为移动机器人系统的轨迹跟踪建立一个合适的模型。介绍了一种轮式机器人滑模轨迹跟踪控制方法。滑模控制是一个鲁棒的控制方法,能渐近的按一条所期望的轨迹稳定移动机器人。以之为基础,描述了轮式机器人的动力学模型并在二维坐标下建立了运动学方程,根据运动学方程设计滑模控制器,该控制器使得机器人的位置误差收敛到零。     

Design and implementation of the motion control system of the mobile robot based on PID

A kind of motion control system of the autonomous mobile robot was introduced,and a PID closed-loop control method was proposed that controlling the robot moving along the expected direction and speed effectively through establishing the kinematics model of the autonomous mobile robot.In addition,the modular software program and the hardware system were developed whose main components were the STC12C5A60S2 microprocessor,the MC33886 motor driver chip and hall sensors.Finally,experiments proves the control method and the system effective and stable.     

基于免疫进化算法的轮式移动机器人非完整运动规划

本文阐述了轮式移动机器人非完整运动的最优规划问题,在系统的非完整特性基础上,将轮式移动机器人的运动规划转化为非线性系统最优控制问题。在最优控制中引入了人工免疫算法,替代了传统的迭代方法,提出了基于人工免疫算法的非完整运动规划的最优控制方法。通过抗体编码和亲合力函数给出了算法的具体实现步骤,并且进行了仿真实验。实验结果表明算法的有效性和可行性。     

A cooperative multi-robot architecture for moving a paralyzed robot

In this paper we study the possibility of cooperation between reactive and deliberative based robots, which are generally considered as antinomic approaches. We focus on a case study composed, on the one hand, of an “intelligent” robot that submits failures which prevent it from moving, and on the other hand, of a pool of simple autonomous mobile robots which are able to push. The paralyzed robot can broadcast signals to recruit mobile robots and to be pushed by them. These signals are interpreted as force fields by agents in order to compute their reactive behavior. We present these different robot behaviors and analyse two experiments. We show that the proposed system provides a control loop which is independent of the number of robots pushing on each arm, showing that a combination of multi-agent and deliberative architectures can define intelligent and robust multi-robot systems.     

A path tracking control system for autonomous mobile robots: an experimental investigation

A path tracking control system developed for autonomous mobile robots driven by wheels is described. In conventional approaches, the path is usually planned by smooth curves with curvature-continuity and a path tracking controller is independently designed to compensate the path error occurring in the navigation. However, smooth path planning is difficult to execute on-line due to the computational burden. In addition, the conventional path tracking algorithm often causes unpredictable tracking motion when large path error occurs. In previous work, the present authors presented a bang-bang path tracking algorithm by which smooth and stable tracking motion could be obtained even for the path given by simple combination of straight lines or circles and its effectiveness was proven via preliminary simulation studies. However, there still remained the problem that the design parameter called landing coefficient could not be optimally chosen and performance verification through real system application was not accomplished. In this study, we improve the algorithm which can determine the design parameters analytically and verify its performance by implementing the algorithm in an actual mobile robot control system designed using a personal computer. To investigate the performance of the control system, a series of path tracking experiments was conducted for a two-wheel driven robot developed in the laboratory.     

Track--Stair Interaction Analysis and Online Tipover Prediction for a Self-Reconfigurable Tracked Mobile Robot Climbing Stairs

This paper analyzes track-stair interactions and develops an online tipover prediction algorithm for a self-reconfigurable tracked mobile robot climbing stairs, which is vulnerable to tipping-over. Tipover prediction and prevention for a tracked mobile robot in stair climbing are intractable problems because of the complex track--stair interactions. Unlike the wheeled mobile robots, which are normally assumed to obey the nonholonomic constraints, slippage is unavoidable for a tracked mobile robot, especially in stair climbing. Furthermore, the track-stair interactive forces are complicated, which may take the forms of grouser-tread hooking force, track--stair edge frictional force, grouser-riser clutching force, and even their compositions. In this paper, the track--stair interactions are analyzed systematically, and tipover stability criteria are derived for a tracked mobile robot climbing stairs. An online tipover prediction algorithm is also developed, which forms an essential part for autonomous and semiautonomous stair-climbing control. The effectiveness of the proposed algorithms are verified by experiments.     

Full-state tracking and internal dynamics of nonholonomic wheeled mobile robots

In the paper, the stable full-state tracking problem is investigated for nonholonomic wheeled mobile robots under output-tracking control laws. Dynamics of such wheeled mobile robots are nonholonomic and pose challenging problems for control design and stability analysis. The dynamics formulated in terms of full-state tracking errors offer some properties that allow better understanding of the internal and zero dynamics of the tracking-error system and more insights to the trajectory tracking stability. Output functions are chosen as virtual reference points for various types of wheeled mobile robots in aid of output controller designs. Sufficient conditions are derived to ensure the stable full-state trajectory tracking under output-tracking control laws. A type (1,1) mobile robot of car-like configuration is studied in detail and further numerical analysis provides more results which are beyond the reach of analytical means. An example and simulation results are presented to confirm the theory and observations.     

Efficient rolling motion for snake-like robots utilizing center of gravity shift

Snake-like robots have attracted attention as robots that can travel over rough terrain where wheeled mobility mechanisms cannot. Previous research on snake-like robots has mainly focused on the biological movement of snakes; therefore, the issue of power consumption caused by driving a large number of actuators still remains unaddressed. In this study, we propose an efficient movement method using the movement of the center of gravity (COG) as a solution to the above-mentioned problem. In the proposed method, the snake-like robot is first transformed into a wheel shape, and then, some motors of the joint are moved to shift the COG and rotate the robot. Therefore, good movement efficiency can be achieved on leveled terrain by the rolling movement, and a snake-like undulating drive with high running performance can be selected on underwater and rough terrain. To realize the proposed movement method, we propose a method for switching between the rotational movement and undulation drive modes. However, the rolling motion with a COG shift needs a design of an appropriate orbit of the eccentric COG and timing of the motion stage transition. In this study, we demonstrate the rolling motion design with a simplified equation of motion. Next, experiments are conducted to verify the traveling efficiency in the proposed rolling mode, and it is proven that the method can achieve twice the traveling efficiency of the undulating motion.     

基于Backstepping和神经动力学的非完整移动机器人点镇定

以非完整移动机器人为控制对象,围绕机器人运动控制中重要的点镇定问题进行深入研究.本文在考虑移动机器人模型和极坐标系下的位姿误差模型基础上,提出一种Backstepping与神经动力学相结合方法,设计具有渐近稳定的点镇定控制器.该控制方法能有效解决因初始误差存在而引起的速度和力矩突变问题,使机器人从静止状态快速收敛到任意...     

Autonomous decentralized control for formation of multiple mobile robots considering ability of robot

The purpose of this study is to control multiple mobile robots in formation considering the ability of a robot using the "Leader-Following" strategy. There are three features of this study. First, a performance index that shows mobile robot ability is quantified. Specifically, maximum acceleration and maximum velocity of a robot are defined by maximum admissible rotation and maximum continuous torque of a motor. The performance index is quantified from arrival time on the destination using these parameters. Second, a new controller is proposed based on the performance index, so that robots can be controlled according to robot ability. Third, a compliance controller using a virtual repulsion is suggested in this paper, so that each robot can avoid collision. Finally, simulation and experiments are done in a real-time system using RT-Messenger. RT-Messenger allows robots to transmit information regarding their positions to each other in real time. These results shows the validity of the proposed method.     

Model-Reference Control Approach to Obstacle Avoidance for a Human-Operated Mobile Robot

Because the obstacle-avoidance function is indispensable for providing the safe and easy operation of human-operated robotic systems, this paper deals with the obstacle-avoidance control for a human-operated mobile robot in unknown environments. A general type of two-wheeled mobile robot with inexpensive distance sensors to detect obstacles is considered. Because the robot cannot move in arbitrary directions due to a nonholonomic constraint, we propose a model-reference control approach, in which a reference model generates the desired trajectory to satisfy the nonholonomic constraint, and the robot follows the desired trajectory. The reference model has the steering-like and brake-like functions that are adjusted according to the distance-sensor information. The stability of the proposed control system is analyzed with a linear model. The effectiveness of the proposed method is confirmed by experiments in which several operators handle the robot in an environment with obstacles.     

Multi-hierarchy interaction control of a redundant robot using impedance learning

The control of robots with a compliant joint motion is important for reducing collision forces and improving safety during human robot interactions. In this paper, a multi-hierarchy control framework is proposed for the redundant robot to enable the robot end-effector to physically interact with the unknown environment, while providing compliance to the joint space motion. To this end, an impedance learning method is designed to iteratively update the stiffness and damping parameters of the end-effector with desired performance. In addition, based on a null space projection technique, an extra low stiffness impedance controller is included to improve compliant joint motion behaviour when interaction forces are acted on the robot body. With an adaptive disturbance observer, the proposed controller can achieve satisfactory performance of the end-effector control even with the external disturbances in the joint space. Experimental studies on a 7 DOF Sawyer robot show that the learning framework can not only update the target impedance model according to a given cost function, but also enhance the task performance when interaction forces are applied on the robot body.     

中型组机器人运动控制系统的FPGA设计

以RoboCup中型组足球机器人为实验平台,提出一种基于FPGA的全方位移动足球机器人运动控制系统的实现方法。首先分析和研究三轮全方位移动机器人的运动学特性,建立其运动控制模型,然后以FPGA为主要处理器,设计了PID速度闭环控制算法,实现了对机器人的精确控制。实验发现,该设计方法具有很好的实时性,能够对全方位移动机器人进行快速、准确的控制。     

基于无线传感网络的移动机器人通信研究

文章对无线传感网络在机器人设计中的应用进行了研究,提出了一种基于Ad hoc网络的分布式无线令牌环协议的机器人通信系统实现方案,分析了其在机器人通信系统应用中的可行性.文中给出了基于无线传感网络的机器人通信系统的软硬件设计方案,并对其在移动机器人通信系统中的应用问题进行了探讨,最终提出了无线传感器网络应用于移动机器人通信系统的实现方法.     

A dynamic detection method to improve SLAM performance

Simultaneous localization and mapping (SLAM) technology is a research hotspot in the field of intelligent mobile robot, and many researchers have developed many classic systems in the past few decades. However, most of the existing SLAM methods assume that the environment of the robot is static, which results in the performance of the system being greatly reduced in the dynamic environment. To solve this problem, a new dynamic object detection method based on point cloud motion analysis is proposed and incorporated into ORB-SLAM2. First, the method is regarded as a preprocessing stage, detecting moving objects in the scene, and then removing the moving objects to enhance the performance of the SLAM system. Experiments performed on a public RGB-D dataset show that the motion cancellation method proposed in this paper can effectively improve the performance of ORB-SLAM2 in a highly dynamic environment.     

基于Kinect深度技术的障碍物在线快速检测算法

针对在未知环境中移动机器人自主导航面临的障碍物实时检测问题,提出了一种基于Kinect深度技术的障碍物在线快速检测算法。在深度摄像机标定基础上,分析了摄像机运动造成视频流中的场景变化,重点研究了室内动态背景下的Kinect深度图像特征和障碍物在线快速检测。建立室内动态背景模型,采用背景减除法和连通体分析提取障碍物并归类,实现了对Kinect视频序列图像的在线快速检测。以轮式移动机器人为实验平台,验证了所提出算法的实时性、准确性和鲁棒性。