模糊PID控制在轮式机器人上的应用

近年来运动控制技术发展迅速,由于轮式移动机器人系统的非线性和常规PID控制方法的不足,将传统的PID控制技术和普通的模糊控制技术相结合,设计了一种基于参数自整定的模糊PID运动控制系统,具体介绍了运动控制系统的构成、模糊PID控制系统的原理以及模糊HD控制器的设计步骤,并对该控制方案进行数字仿真。     

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。     

松软月面上月球车动力学建模及运动控制研究

通过分析松软月面上车轮下陷原因,建立了车轮与月面相互作用模型,在此基础上对ADAMS进行二次开发,通过等效转换建立了松软月面上月球车仿真模型。由于月球车行走运动时需要考虑能耗、驱动能力等多方面因素,以速度跟踪和驱动能力为控制目标,设计了基于车轮滑转率的协调控制器,并对不同运动工况进行了动力学仿真及分析,验证了所提方法的有效性,为下一步综合设计月球车运动控制策略提供了依据。     

基于切换参数PI控制器的运动控制系统设计与实现

为了提高运行控制系统的控制精度,减少运动过程中的震荡,提出一种基于切换参数PI控制器的运动控制系统;首先运动控制过程中考虑进行PI条件切换,然后利用回调函数,并加入滤波器进行平滑处理,构建了速度控制模块、伺服电机仿真模块,最后采用仿真实验对系统的进行仿真测试;仿真实验结果表明,该运动控制系统可以得到更快、更准确的运动结果,为运动控制系统的设计和调试提供了一种新的研究思路.     

基于状态机的巡线机器人控制系统设计

通过对巡线机器人运动控制系统的分析,提出采用有限状态机实现运动控制系统中的运动保护及机构定位系统的方法.结合巡线机器人运动控制的特殊需求,通过对运动控制系统的时序分析,设计了运动保护及定位系统的状态机.并在可编程器件上实现了巡线机器人运动控制器,从而给出了基于可编程器件设计控制系统的一种方法.     

基于自主行为智能体的月球车运动规划与控制

研究基于自主行为智能体的月球车运动规划与控制方法．在基于自主行为智能体的月球车系统结构基础上,首先设计了月球车运动规划与控制的一组基本行为,对其原理进行证明．通过行为状态机对行为进行选择,如果不能保障月球车安全性能,则由运动规划智能体学习其行为参数,并由神经网络记忆．将月球车运动规划与控制分解为行为设计与学习两个过程,使月球车控制系统易于加入先验知识．同时,月球车运动规划能够满足其机动性与地形传送性约束,保证工程开发的结构化与可实现性．该方法不仅具有实时性,而且对未知环境具有较强的适应能力．仿真研究与实验证明了该方法的有效性．     

基于LabVIEW的仿生型机器马的软件设计

根据开放式运动控制的要求.采用以主计算机作为上位机和以运动控制器作为下位机的方法,设计了一种基于NI运动控制器的6轴并联机器马运动控制系统,并对该系统的功能,硬件结构和软件设计方法进行研究,完成数据及状态显示、机器马运动规划等任务,该系统具有开放性、高速性、实时性和模块化等特点.     

运动控制算法可重构机制

针对步进扫描光刻机运动控制系统调试和运行,提出了一种运动控制算法可重构的机制,实现运动控制算法和关键参数的在线修改;对比分析了不可重构与可重构运动控制软件的设计流程,指出了可重构的优势;为运动控制代码传输设计了VME总线通道并用FPGA实现总线接口,确保运动控制指令的高速稳定传输;设计了运动控制器运算核心DSP的外部接口和运行方式,确保运动控制算法的可控运行;实验结果表明DSP代码可从上位机下载运行,控制系统能灵活的重构运动控制算法,长时间运行稳定,大大提高了光刻机工件台控制系统调试的工作效率。     

标准可加模糊行为系统在避障控制中的应用

为了提高月球车控制系统的可靠性和稳定性,保证其运动规划过程的安全性,并针对月球车运行于非结构化环境中,难以用精确的数学模型描述等特点,将行为控制与模糊控制相结合,提出了月球车运动规划的标准可加模糊行为系统,基于凸和的基本性质,对该系统的有界性、连续性、可导性进行了证明;然后设计了权重系数调整控制器,将趋向目标行为以及避障行为以凸组合的方式进行行为融合,并进行了仿真,仿真结果证明了凸组合方法的有效性以及分析结果的正确性。     

轮式移动机器人与地形交互运动仿真研究

分析了轮式移动机器人（WMR）在不平坦的三维地形上运动的运动学模型,利用速度投影法,得到了一种WMR运动模型的新的形式。基于虚拟现实技术,利用VC + +OpenGL实现了WMR虚拟漫游系统。该系统具有较强的交互性和实时性,为星球探测机器人虚拟导航、遥操作提供了验证平台。     

Design and field testing of a rover with an actively articulated suspension system in a Mars analog terrain

This study presents the electromechanical design, the control approach, and the results of a field test campaign with the hybrid wheeled‐leg rover SherpaTT. The rover ranges in the 150 kg class and features an actively articulated suspension system comprising four legs with actively driven and steered wheels at each leg’s end. Five active degrees of freedom are present in each of the legs, resulting in 20 active degrees of freedom for the complete locomotion system. The control approach is based on force measurements at each wheel mounting point and roll–pitch measurements of the rover’s main body, allowing active adaption to sloping terrain, active shifting of the center of gravity within the rover’s support polygon, active roll–pitch influencing, and body‐ground clearance control. Exteroceptive sensors such as camera or laser range finder are not required for ground adaption. A purely reactive approach is used, rendering a planning algorithm for stability control or force distribution unnecessary and thus simplifying the control efforts. The control approach was tested within a 4‐week field deployment in the desert of Utah. The results presented in this paper substantiate the feasibility of the chosen approach: The main power requirement for locomotion is from the drive system, active adaption only plays a minor role in power consumption. Active force distribution between the wheels is successful in different footprints and terrain types and is not influenced by controlling the body’s roll–pitch angle in parallel to the force control. Slope‐climbing capabilities of the system were successfully tested in slopes of up to 28° inclination, covered with loose soil and duricrust. The main contribution of this study is the experimental validation of the actively articulated suspension of SherpaTT in conjunction with a reactive control approach. Consequently, hardware and software design as well as experimentation are part of this study.     

非对称行星探测车行走系统的动力学仿真及运动性能分析

为了提高探测车在崎岖路面中的运动性能,提出了一种非对称轮式探测车行走系统.该车具有整体式超静定结构,6个车轮通过悬挂装置与车身相连,非对称分布于车体两侧,悬架结构可以主动控制来提高探测车在崎岖路面中的运动性能.采用牛顿-欧拉法建立了行走系统的动力学模型,给出了几何和速度约束方程,采用有限差分法求解由微分方程和代数方程构...     

Theory and experiments in SmartNav rover navigation

This paper describes theoretical and experimental results using the SmartNav rule-free fuzzy rover navigation system. SmartNav divides the terrain perceived by the rover into a number of circular sectors, and evaluates each sector using goal and safety preference factors to differentiate between preferred and unpreferred terrain sectors. The goal-preference factor is used to make sector evaluation based on the sector orientation relative to the designated goal position. The safety-preference factors are used to make sector evaluations on the basis of the sector local and regional terrain hazards. Three methods are developed to blend the three sector evaluations in order to find the effective preference factor for each sector. Two sector selection methods are then described in which the sector preference factors are used to find the heading command for the rover. The rover speed command is also computed based on the goal distance and safety-preference factor of the chosen sector. The above navigation steps are continuously repeated throughout the rover motion. Experimental results are presented to demonstrate the navigational capabilities of SmartNav using a commercial Pioneer 2AT rover traversing a simulated Martian terrain at the JPL Mini Mars Yard.

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Evolution of a Prototype Lunar Rover: Addition of Laser-Based Hazard Detection, and Results from Field Trials in Lunar Analog Terrain

This paper presents the results of field trials of a prototype lunar rover traveling over natural terrain under safeguarded teleoperation control. Both the rover and the safeguarding approach have been used in previous work. The original contributions of this paper are the development and integration of a laser hazard detection system, and extensive field testing of the overall system. The laser system, which complements an existing stereo vision system, is based on a line-scanning laser ranger viewing the area 1 meter in front of the rover. The laser system has demonstrated excellent performance: zero misses and few false alarms operating at 4 Hz. The overall safeguarding system guided the rover 43 km over lunar analogue terrain with 0.8 failures per kilometer.     

Ambler: an autonomous rover for planetary exploration

The authors are building a prototype legged rover, called the Ambler (loosely an acronym for autonomous mobile exploration robot) and testing it on full-scale, rugged terrain of the sort that might be encountered on the Martian surface. They present an overview of their research program, focusing on locomotion, perception, planning, and control. They summarize some of the most important goals and requirements of a rover design and describe how locomotion, perception, and planning systems can satisfy these requirements. Since the program is relatively young (one year old at the time of writing) they identify issues and approaches and describe work in progress rather than report results. It is expected that many of the technologies developed will be applicable to other planetary bodies and to terrestrial concerns such as hazardous waste assessment and remediation, ocean floor exploration, and mining     

Adaptive localization and mapping with application to planetary rovers

Future exploration rovers will be equipped with substantial onboard autonomy. SLAM is a fundamental part and has a close connection with robot perception, planning, and control. The community has made great progress in the past decade by enabling real‐world solutions and is addressing important challenges in high‐level scalability, resources awareness, and domain adaptation. A novel adaptive SLAM system is proposed to accomplish rover navigation and computational demands. It starts from a three‐dimensional odometry dead reckoning solution and builds up to a full graph optimization that takes into account rover traction performance. A complete kinematics of the rover locomotion system improves the wheel odometry solution. In addition, an odometry error model is inferred using Gaussian processes (GPs) to predict nonsystematic errors induced by poor traction of the rover with the terrain. The nonparametric GP regression serves to adapt the localization and mapping to the current navigation demands (domain adaptation). The method brings scalability and adaptiveness to modern SLAM. Therefore, an adaptive strategy develops to adjust the image frame rate (active perception) and to influence the optimization backend by including high informative keyframes in the graph (adaptive information gain). The work is experimentally verified on a representative planetary rover under a realistic field test scenario. The results show a modern SLAM systems that adapt to the predicted error. The system maintains accuracy with less number of nodes taking the most benefit of both wheel and visual methods in a consistent graph‐based smoothing approach.     

Game theory basis for control of long-lived lunar/planetary surface robots

Current and future NASA robotic missions to planetary surfaces are tending toward longer duration and are becoming more ambitious for rough terrain access. For a higher level of autonomy in such missions, the rovers will require behavior that must also adapt to declining health and unknown environmental conditions. The MER (Mars Exploration Rovers) called Spirit and Opportunity have both passed 600 days of life on the Martian surface, with extensions to 1000 days and beyond depending on rover health. Changes in navigational planning due to degradation of the drive motors as they reach their lifetime are currently done on Earth for the Spirit rover. The upcoming 2009 MSL (Mars Science Laboratory) and 2013 AFL (Astrobiology Field Laboratory) missions are planned to last 300–500 days, and will possibly involve traverses on the order of multiple kilometers over challenging terrain. This paper presents a unified coherent framework called SMART (System for Mobility and Access to Rough Terrain) that uses game theoretical algorithms running onboard a planetary surface rover to safeguard rover health during rough terrain access. SMART treats rover motion, task planning, and resource management as a Two Person Zero Sum Game (TPZSG), where the rover is one player opposed by the other player called “nature” representing uncertainty in sensing and prediction of the internal and external environments. We also present preliminary results of some field studies. Terry Huntsberger is a Principal Member of the Technical Staff in the Advanced Robotic Controls Group at NASA’s Jet Propulsion Laboratory in Pasadena, CA, where he is the Manager for numerous tasks in the areas of multi-robot control systems, and rover systems for access to high risk terrain. He is an Adjunct Professor and former Director of the Intelligent Systems Laboratory in the Department of Computer Science at the University of South Carolina. His research interests include behavior-based control, computer vision, neural networks, wavelets, and biologically inspired system design. Dr. Huntsberger has published over 120 technical articles in these and associated areas. He received his PhD in Physics in 1978 from the University of South Carolina. He is a member of SPIE, ACM, IEEE Computer Society, and INNS. Abhijit Sengupta is a Senior Member of Engineering Staff in the Advanced Concepts and Architecture Group of the Jet Propulsion Laboratory in Pasadena, California. His research interest includes distributed architecture, algorithm design and fault-tolerant computing and he has more than 100 publications in these and other related areas. Prior to joining JPL in 2001, he was a Professor in the Department of Computer Science and Engineering at the University of South Carolina. He received his Ph.D. in 1976 in Electronic Engineering from the University of Calcutta.     

Systematic kinematics analysis and balance control of high mobility rovers over rough terrain

The paper proposes a systematic method for kinematics modeling, analysis and balance control of a general high mobility wheeled rover traversing uneven terrain. The method is based on the propagation of position and orientation velocities starting from the rover reference frame and going through various joints and linkages to the wheels. The concept of an extended DH table is introduced for rovers and mobile robots, and equations of the motion are set up in a compact form. Actuation kinematics and balance control are formulated for rovers traversing bumpy terrains. To illustrate the proposed kinematics modeling and balancing, the method is applied to a high mobility rover and simulation results with various terrains are presented.     

An intelligent terrain-based navigation system for planetary rovers

A fuzzy logic framework for onboard terrain analysis and guidance towards traversable regions. An onboard terrain-based navigation system for mobile robots operating on natural terrain is presented. This system utilizes a fuzzy-logic framework for onboard analysis of the terrain and develops a set of fuzzy navigation rules that guide the rover toward the safest and the most traversable regions. The overall navigation strategy deals with uncertain knowledge about the environment and uses the onboard terrain analysis to enable the rover to select easy-to-traverse paths to the goal autonomously. The navigation system is tested and validated with a set of physical rover experiments and demonstrates the autonomous capability of the system