全向移动爬壁机器人设计及其运动特性研究北大核心CSCD

设计了一种在壁面上运动的全向移动机器人。该机器人采用三轮全向运动方式与负压气室附着方式相结合的机械结构,既可以在壁面上灵活地完成平面内三自由度的连续运动,又具有较好的附着鲁棒性。针对机器人系统在壁面上运动时受到重力而导致的与在地面上运动特性之间的差异,推导了机器人各轮压地力关于壁面上朝向角的表达式,并由滑移临界状态推导得到机器人在任意朝向下各方向的最大加速度,最后通过仿真实验验证了各轮压地力模型与滑移临界状态模型的正确性。该研究能够为全向移动爬壁机器人的机械结构设计提供指导,为其路径规划与运动控制提供加速度约束。     

基于麦克纳姆轮的AGV小车

为了实现工业物联网在物流方面的自动化、智能化,解决传统四轮小车运动模式单一的情况,设计了一种基于麦克纳姆轮的AGV小车。该设计以STM32F103ZET6为核心,以多种传感器为载体,实现了小车多输入协同控制运行;以麦克纳姆轮作为驱动轮,使小车具有8个方向前进的方式;采用WiFi通信,完成小车与上位机的信息交互。该设计具有灵活性高、稳定可靠、实时性好的特点。     

基于互补滤波的两轮自平衡小车的实现

要使两轮自平衡小车协同运动、平衡稳定、有效控制,最为关键的首要因素是准确、快速地解算出其运动姿态信息。该文针对姿态信息解算的卡尔曼滤波解算复杂、运算量大等缺点,采用互补滤波将倾角、加速度传感器信息进行数据融合、优化,得到与实际姿态信息相一致的最优估计值。再综合视觉传感器,两轮自平衡小车自动调整运动姿态、及时修正并回归至平衡位置,实现平稳控制。提出利用传感器—倾角、加速度、磁力计、视觉,互补滤波,ARM微控制器,4G通信等多种技术,设计出基于互补滤波的两轮自平衡小车。详细阐述了工作原理、系统架构、硬件设计及姿态信息检测、互补滤波、方向检测等算法。实践表明,基于互补滤波的两轮竞速自平衡小车姿态解算准确快速、运动控制精准、转弯快速。     

基于模糊逻辑的轮式移动机器人运动控制的设计与研究

主要对四轮移动小车的运动轨迹控制部分进行研究,采用模糊控制方法,控制各个电机的功率和转向,实现四轮小车转速较大范围误差调节,加快电机启动速度,达到控制平滑和节能的目的,使运动控制系统兼顾实时性高、稳定性强等设计要点;并可通过模糊控制规则库的扩充,提高小车的灵活性。对运动状态进行闭环控制,通过测量脉冲数检测小车是否按所接收指令运动,以达到一定的控制精度,保证小车运动达到预期目的。     

基于模糊逻辑的轮式移动机器人运动控制的设计与研究

主要对四轮移动小车的运动轨迹控制部分进行研究,采用模糊控制方法,控制各个电机的功率和转向,实现四轮小车转速较大范围误差调节．加快电机启动速度。达到控制平滑和节能的目的,使运动控制系统兼顾实时性高、稳定性强等设计要点：并可通过模糊控制规则库的扩充,提高小车的灵活性。对运动状态进行闭环控制．通过测量脉冲数检测小车是否按所接收指令运动,以达到一定的控制精度,保证小车运动达到预期目的。     

基于关联规则挖掘的全向轮移动机器人目标跟踪控制系统设计

为使全向轮机器人在移动过程中所捕获到的目标对象能够完全符合理想目标设定条件,准确追踪目标节点的运动行为,设计基于关联规则挖掘的全向轮移动机器人目标跟踪控制系统。根据CAN主控框架的部署形式,按需连接核心管控电路与I/O跟踪模块,分别以转向控制器、速度控制器为例,完善全向轮控制结构的物理作用能力,实现机器人目标跟踪控制系统的应用结构部件设计。在此基础上,定义频繁项集合,按照具体的关联规则特征描述结果,确定挖掘程序指令的执行能力,得到准确的关联离散度指标计算结果,实现控制系统的关联规则挖掘,再联合相关硬件设备结构,完成基于关联规则挖掘的全向轮移动机器人目标跟踪控制系统设计。分析对比实验结果可知,随着关联规则挖掘控制系统的应用,全向轮机器人在移动过程中所捕获到的目标对象能够将理想目标完全包含在内,可以辅助全向轮移动机器人更加准确地追踪目标节点的运动行为,符合实际应用需求。     

自动循迹小车的位置和速度控制

为了实现小车快速平稳的循迹运动,采用5个红外光电传感器检测轨道的偏差,前部安装一个万向轮,通过后部左轮和右轮的速度差来控制小车的转向。分析了小车转弯时的运动轨迹,讨论了左轮和右轮速度与转弯半径等参数之间的关系;设计了位置+速度的串级PID控制模型,采用速度最快策略进行速度分配,确保小车在转向时快速流畅,使小车能够迅速、平稳、准确地沿赛道轨迹运动。该小车的设计方案和串级控制模型也可应用于无人车间自动搬运的AGV小车、自主移动机器人等服务机器人的循迹及定位控制。     

两轮自平衡小车的研究与实现

介绍以飞思卡尔MK60N512VMD100单片机为控制器和以MMA7260加速度传感器及ENC-03角速度传感器等传感器元件作为传感检测系统的两轮自平衡小车系统。阐述了基于加速度传感器和角速度传感器获取两轮小车倾斜角度的滤波算法及其实现、自平衡控制算法及其实现,电机控制策略等相关问题。实验结果表明,此小车具有较好的平衡性和稳定性。     

基于STM32的两轮平衡车设计

近年来,两轮自平衡车的研究与应用获得了迅猛发展.本文提出了一种两轮自平衡小车的设计方案,采用陀螺仪ENC-03 以及MEMS 加速度传感器MMA7260 构成小车姿态检测装置,使用卡尔曼滤波完成陀螺仪数据与加速度计数据的数据融合.系统选用飞思卡尔16 位单片机MC9S12XS128 为控制核心,完成了传感器信号的处理,滤波算法的实现及车身控制,人机交互等.     

基于Arduino/Android的小车蓝牙控制系统的设计与实现

以Arduino单片机的硬件平台为核心控制器,结合Eclipse开发环境和Arduino IDE编程语言完成小车的主控程序,通过Android手机蓝牙客户端与蓝牙模块服务端的通信实现小车的智能策略控制。小车整体采用前桥驱动、后轮转向的布局方式,两轮各用一个直流电机配合齿轮减速机构实现运作。实验表明:该控制系统实现了基于Android手机的蓝牙控制小车的运行功能,实现小车的前进、后退和转弯等多种运动形态。该控制系统结构简单、操作方便,为新型智能控制系统的设计提供了参考依据。     

2020版Euro NCAP碰撞MPDB测试对汽车设计的影响

2020版Euro NCAP更新了汽车碰撞安全试验工况。为研究新工况下的碰撞安全性,以不同质量的车辆作为研究对象,对比2020版Euro NCAP MPDB工况与现行ODB工况下被撞车辆的结构变形以及加速度波形的差异。研究表明:新工况与现行工况下的被撞车辆表现差异明显,对中小型车辆影响较大。针对分析结果提出改进思路,为新车型的碰撞安全性能研发提供参考。     

Collision-free control of an omni-directional vehicle

This study addresses the problem of controlling an omni-directional vehicle with both state and control dependent constraints. The task of the vehicle is to attain its desired final position given in the task space. The control constraints resulting from the physical abilities of actuators driving the vehicle wheels are also taken into account during the robot movement. The problem of collision avoidance is solved here based on an exterior penalty function approach which results in smooth vehicle velocities near obstacles. Provided that, a solution to the aforementioned vehicle task exists, the Lyapunov stability theory is used to derive the control scheme. The numerical simulation results carried out for the omni-directional vehicle operating in both a constraint-free task space and task space including obstacles, illustrate the performance of the proposed controllers.     

On the Generation of Trajectories for Multiple UAVs in Environments with Obstacles

This paper presents a methodology based on a variation of the Rapidly-exploring Random Trees (RRTs) that generates feasible trajectories for a team of autonomous aerial vehicles with holonomic constraints in environments with obstacles. Our approach uses Pythagorean Hodograph (PH) curves to connect vertices of the tree, which makes it possible to generate paths for which the main kinematic constraints of the vehicle are not violated. These paths are converted into trajectories based on feasible speed profiles of the robot. The smoothness of the acceleration profile of the vehicle is indirectly guaranteed between two vertices of the RRT tree. The proposed algorithm provides fast convergence to the final trajectory. We still utilize the properties of the RRT to avoid collisions with static, environment bound obstacles and dynamic obstacles, such as other vehicles in the multi-vehicle planning scenario. We show results for a set of small unmanned aerial vehicles in environments with different configurations.     

Digital RAC with a disturbance observer for underwater vehicle-manipulator systems

Most control methods of underwater vehiclemanipulator systems (UVMS) are based on the computed torque method that is used for underwater robotic vehicles. We have proposed a resolved acceleration control (RAC) method for UVMS. In this article, we propose a disturbance compensation control method for both vehicle and manipulator based on the RAC method. Experimental results using an underwater robot with a vertical planar 2-link manipulator show that the proposed control method has good control performance.     

基于空时块编码的飞行器全向无线通信分析

将空时块编码引入飞行器全向无线传输中,用于抑制传统飞行器全向通信中不同天线发送信号在空间中发生干涉的问题.从等效合成天线增益和适合的应用场景两方面对基于空时块编码的传输方案的性能进行分析和讨论.针对不同的传输场景进行了仿真评估.仿真结果表明:使用空时块编码的方案性能与天线数量和天线方向图有关;相比传统方案,采用空时块编码能够有效抑制信号在空间中的深衰减,降低通信链路中断概率,从而大幅改善飞行器全向通信能力.     

A study of tipping stability for omnidirectional mobile robot with active dual-wheel caster assemblies

A holonomic omnidirectional mobile robot with active dual-wheel caster assemblies is proposed as a robotic transport vehicle. With concern to the existence of sudden acceleration and other dynamical effects during maneuver, the tip-over instability monitoring is very important to prevent any unexpected injuries and property damage. This work presents the preventive method of the tip-over occurrence by estimating the tipping direction and stability metrics. The dynamical model of the omnidirectional mobile robot is derived to estimate the net force from the supporting reaction force at each wheel which is caused by the inertial and external forces. The direction of tipping and stability metric is estimated using moments stability measure. The performance of the tip-over prediction for an omnidirectional mobile robot with active dual-wheel assemblies is shown by the conducted simulations.     

First results in omni-directional visual servoing

In this paper, we describe a visual servoing system developed as a human-robot interface to drive a mobile robot toward any chosen target. An omni-directional camera is used to get the 360° of field of view and an efficient tracking technique is developed to track the target. The use of the omni-directional geometry eliminates many of the problems common in visual tracking and makes the use of visual servoing a practical alternative for robot-human interaction. The experiments demonstrate that it is an effective and robust way to guide a robot. In particular, the experiments show robustness of the tracker to loss of template, vehicle motion, and change in scale and orientation.     

一种仿人机器人跑步状态分析模型

依据仿人机器人跑步的动力学特性,通过对仿人机器人虚拟加速度传感器输出的信号进行分析,建立了仿人机器人跑步相关特征值的概率模型.针对仿人机器人的结构,分析了在整个跑步过程中惯性力和弯矩的作用,对跑步状态的影响,获取虚拟加速度传感器输出的信号,采用小波变换分析动态信号,同时进行快速傅里叶变换,在频域上提取能量特征值.使用马氏距离作为稳定跑步的判定标准,并给出了定量描述,在ADAMS软件中搭建仿人机器人,虚拟加速度传感器设置在质心处,进行跑步仿真实验,仿真实验结果表明,该模型能够反映仿人机器人的跑步特性,仿人机器人能够在跑步状态发生改变时,根据跑步特征及时调整步态,保证其稳定性.     

Visuo-inertial stabilization in space-variant binocular systems

Stabilization of gaze is a major functional prerequisite for robots exploring the environment. The main reason for a “steady-image” requirement is to prevent the robot’s own motion to compromise its “visual functions”. In this paper we present an artificial system, the LIRA robot head, capable of controlling its cameras/eyes to stabilize gaze. The system features a stabilization mechanism relying on principles exploited by natural systems: an inertial sensory apparatus and images of space-variant resolution. The inertial device measures angular velocities and linear acceleration along the vertical and horizontal fronto-parallel axes. The space-variant image geometry facilitates real-time computation of optic flow and the extraction of first-order motion parameters. Experiments which describe the performance of the LIRA robot head are presented. The results show that the stabilization mechanism improves the reactivity of the system to changes occurring suddenly at new spotted locations.     

Iterative Path Tracking of an Omni-Directional Mobile Robot

We propose a path-tracking algorithm that is developed using an iterative learning control (ILC) technique and use the algorithm to control an omni-directional mobile robot. The proposed algorithm can be categorized as an open–closed PD-type ILC; it generates robot velocity commands by a PD-type ILC update rule using both previous and current information. When applied to the omni-directional mobile robot, it can decrease position errors and track the desired trajectory. Under the general problem setting that includes a mobile robot, we show that the proposed algorithm guarantees that the system states, outputs and control inputs converge to within small error bounds around the desired ones even under state disturbances, measurement noises and initial state errors. By using simulation and experimental tests, we demonstrate that the proposed algorithm converges fast to the desired path, and results in small root-mean-square (r.m.s.) position error under various surface conditions. The proposed algorithm shows better path-tracking performance than the conventional PID algorithm and achieves faster convergence and lower r.m.s. error than the existing two ILC algorithms.