Rubbing shoulders with mobile service robots

This paper is not about the details of yet another robot control system, but rather the issues surrounding realworld robotic implementation. It is a fact that in order to realise a future where robots co-exist with people in everyday places, we have to pass through a developmental phase that involves some risk. Putting a “Keep Out, Experiment in Progress” sign on the door is no longer possible since we are now at a level of capability that requires testing over long periods of time in complex realistic environments that contain people. We all know that controlling the risk is important – a serious accident could set the field back globally – but just as important is convincing others that the risks are known and controlled. In this article, we describe our experience going down this path and we show that mobile robotics research health and safety assessment is still unexplored territory in universities and is often ignored. We hope that the article will make robotics research labs in universities around the world take note of these issues rather than operating under the radar to prevent any catastrophic accidents.

Bringing the farmer perspective to agricultural robots

The research reported in this paper explores autonomous technologies for agricultural farming application and is focused on the development of multiple-cooperative agricultural robots (AgBots). These are highly autonomous, small, lightweight, and unmanned machines that operate cooperatively (as opposed to a traditional single heavy machine) and are suited to work on broadacre land (large-scale crop operations on land parcels greater than 4,000m2). Since this is a new, and potentially disruptive technology, little is yet known about farmer attitudes towards robots, how robots might be incorporated into current farming practice, and how best to marry the capability of the robot with the work of the farmer. This paper reports preliminary insights (with a focus on farmer-robot control) gathered from field visits and contextual interviews with farmers, and contributes knowledge that will enable further work toward the design and application of agricultural robotics.

Optimal sleep-wake scheduling for quickest intrusion detection using sensor networks

We consider the problem of quickest detection of an intrusion using a sensor network, keeping only a minimal number of sensors active. By using a minimal number of sensor devices, we ensure that the energy expenditure for sensing, computation and communication is minimized (and the lifetime of the network is maximized). We model the intrusion detection (or change detection) problem as a Markov decision process (MDP). Based on the theory of MDP, we develop the following closed loop sleep/wake scheduling algorithms: (1) optimal control of Mk+1, the number of sensors in the wake state in time slot k + 1, (2) optimal control of qk+1, the probability of a sensor in the wake state in time slot k + 1, and an open loop sleep/wake scheduling algorithm which (3) computes q, the optimal probability of a sensor in the wake state (which does not vary with time), based on the sensor observations obtained until time slot k. Our results show that an optimum closed loop control on Mk+1 significantly decreases the cost compared to keeping any number of sensors active all the time. Also, among the three algorithms described, we observe that the total cost is minimum for the optimum control on Mk+1 and is maximum for the optimum open loop control on q.

Principle of a Dual Current Source Converter for AC Motor Drives

The principle of operation of a dual current source converter is briefly explained. The combination of two single current source converters (SCSC) to form a ``dual (duplex) current source converter'' (DCSC) is proposed. The DCSC is shown to have the following merits: 1) it retains all the advantages of the SCSC; 2) it reduces the harmonic content of the current waveform considerably; and 3) since the load current is shared equally between two current source converters, ratings of the individual components employed in the circuit are considerably lowered. A DCSC can be an attractive choice for sophisticated large horsepower drives where a good performance of the drive rather than cost is a prime factor. An open-loop control scheme employing the DCSC for an ac motor drive has been successfully implemented in the laboratory. Oscillograms of the improved load current waveforms are shown.

Optimal Sleep-Wake Scheduling for Quickest Intrusion Detection using wireless sensor Networks

We consider the problem of quickest detection of an intrusion using a sensor network, keeping only a minimal number of sensors active. By using a minimal number of sensor devices,we ensure that the energy expenditure for sensing, computation and communication is minimized (and the lifetime of the network is maximized). We model the intrusion detection (or change detection) problem as a Markov decision process (MDP). Based on the theory of MDP, we develop the following closed loop sleep/wake scheduling algorithms: 1) optimal control of Mk+1, the number of sensors in the wake state in time slot k + 1, 2) optimal control of qk+1, the probability of a sensor in the wake state in time slot k + 1, and an open loop sleep/wake scheduling algorithm which 3) computes q, the optimal probability of a sensor in the wake state (which does not vary with time),based on the sensor observations obtained until time slot k.Our results show that an optimum closed loop control onMk+1 significantly decreases the cost compared to keeping any number of sensors active all the time. Also, among the three algorithms described, we observe that the total cost is minimum for the optimum control on Mk+1 and is maximum for the optimum open loop control on q.

AI in locomotion: Challenges and perspectives of underactuated robots

This article discusses the issues of adaptive autonomous navigation as a challenge of artificial intelligence. We argue that, in order to enhance the dexterity and adaptivity in robot navigation, we need to take into account the decentralized mechanisms which exploit physical system-environment interactions. In this paper, by introducing a few underactuated locomotion systems, we explain (1) how mechanical body structures are related to motor control in locomotion behavior, (2) how a simple computational control process can generate complex locomotion behavior, and (3) how a motor control architecture can exploit the body dynamics through a learning process. Based on the case studies, we discuss the challenges and perspectives toward a new framework of adaptive robot control. © Springer-Verlag Berlin Heidelberg 2007.

基于解耦控制的SCARA机器人轨迹跟踪控制器设计

SCARA型机器人的控制问题由于其动力学模型中没有重力矩项的作用而得以简化,由于在实际应用中经常要求其高速运动,则对具有强耦合的哥氏力与向心力的控制就成为制约其系统性能的重要问题。提出通过线性变换对机器人系统解耦,将高阶系统转化为解耦的低阶系统进行控制的方法,并且应用极点配置对解耦的系统求解机器人控制器。该方法无需测量关节速度和加速度,只需要测量关节位置信号。所提出的控制器既能保证闭环系统全局渐进稳定,又能通过对线性化系统闭环极点的配置来获得期望的闭环系统响应性能。仿真实验证明了所提出的控制器设计方法的可行性。

基于B/S模式的机器人监控平台的研究

针对目前移动机器人本体研究平台存在局限性的问题,设计出一种基于B/S模式的机器人软件控制系统。系统的实现采用了Java和Vc相结合的方式,在利用Java语言的JNI技术解决接口问题的同时,为了充分利用现有软件模块,提出了一种新型的控制架构,使得整个系统更加完善。通过实验验证了此方法的有效性,有效的提高了系统的可维护性,可扩展性以及可复用性,最终很好实现了控制机器人的目的。

基于MontaVista Linux的开放式机器人控制器研究与实现

本文提出了一种基于MontaVista Linux操作系统的开放式机器人控制器,该系统采用CAN总线作为控制器的系统总线。由于MontaVista Linux操作系统的开放性和良好的移植性,使得系统可以方便扩展、定制不同的应用软件模块和操作系统模块,并且在各种硬件平台间具有良好的移植性。同时由于采用CAN总线作为系统总线,使得系统可灵活配置且可以通过现场总线与其它设备共享数据。

高性能机器人控制系统的研究

本文介绍了高性能机器人控制器的研制情况.该系统具有较高的控制精度,可完成对机器人和多个外部轴的协调控制.为便于国内用户使用,实现了中文界面功能键驱动的汉字编程示教盒.为适应机器人生产线的需要,提供了丰富的联网功能和生产线监控诊断功能.目前该系统已用于新松公司的6kg工业机器人产品中.

井下救援机器人控制系统的仿真与实现

本论文以新松公司和山东省科学院的《井下探测救援机器人的研究》项目为依托，展开井下探测救援机器人控制系统的研究。 我国的煤炭资源十分丰富，是世界上最大的煤炭生产国和消费国。我国煤矿大多数为矿工开采，不安全因素很多，矿井自然条件差，加上技术和管理等诸多方面不到位，使得我国煤矿矿井灾害事故频繁发生，人员伤亡十分惨重，煤矿安全形势已经十分严峻。 传统的救援方法只能通过提升绞车、移动式风车等设备清除垃圾，向井下通风，然后再搜救遇险矿工。这种方式危险性大，伤亡人数多，救援周期长，效率低。因此，迫切需要研发替代或部分替代救险队员进入矿井灾害现场进行环境探测和完成搜救任务的煤矿救援机器人，这对煤矿安全生产，建立特种危险环境下的工业救援体系具有十分重要的意义。 本文以沈阳新松公司的井下救援机器人为研究对象，对移动机器人控制体系结构进行了研究。主要工作如下： 从分析当前的体系结构入手，针对井下救援机器人的具体特点和设计要求，设计了一种以混合式体系结构为基础的移动机器人分布式体控制器。这种结构使用一种基于服务的概念，各个服务提供相当的功能，任意组合服务可以获得相应功能的机器人控制器。服务内部基于纵向的层次划分和横向的功能划分，并融合了特定的反应式行为。 本系统的特点是：自主与监控相结合，动作与感知相结合的行为，采用分布式程序的开发方法并且具有相当程度的开放性。在微软的机器人开发仿真平台上对该体系进行了实验仿真，并在新松公司井下救援机器人开发中实现了该系统。

除草机器人机械臂的逆向求解与控制

设计了一种基于机器视觉导航和杂草识别的除草机器人模型,该机器人能沿作物行间自主行走并能准确地识别和"清除"杂草。设计了除草机器人的机械臂除草执行系统,求取了机械臂运动学逆解,用VC++开发了控制程序。试验显示,图像处理算法所需时间少,能够适应户外自然光线在一定范围的变化,机械臂能够平稳动作并精确定位杂草目标。

一种FPGA的嵌入式可重构机器人控制系统

提出一种基于FPGA的可重构嵌入式微处理器控制系统.在FPGA中嵌入两个NiosⅡ软核,用VHDL语言编写用户自定义组件.在一个由NiosⅡ软核组成的处理器上实现PWM信号生成、编码器信号处理以及多电机同步伺服运算等,在另一个处理器实现机器人任务管理.该控制系统针对微小型爬壁机器人的控制系统设计,不仅具有良好的实时多任务处理能力,而且具有可重构的特点,因而可应用于一类微小型机器人控制系统以提高其设计的灵活性.

基于QNX实时系统的行为辅助机器人控制系统

论文设计研制了行为辅助机器人验证平台,以此平台为基础可以针对行为辅助机器人进行力控制研究。针对机器人力控制的实际要求,设计了行为辅助机器人柔性关节结构,辨识了系统参数。基于QNX实时操作系统设计了控制系统软件。机器人控制系统软件主要包括传感器数据采集和控制算法两部分,可以满足柔性关节控制需求。

小型爬壁机器人系统设计与应用

针对一种小型的双足爬壁机器人,设计开发了基于DSP2812处理芯片的控制系统.该机器人系统采用双足真空吸盘式结构和用3个电机驱动5个关节的欠驱动结构.双足真空吸盘式结构使其可以在光滑的墙面和天棚行走,又能够在交接面之间完成跨步行走.而欠驱动结构减少了电机的数目,从而减小了机器人的尺寸和降低了机器人的质量和能量消耗,但它也给机器人的控制和运动规划带来了新的挑战.已完成的系统设计包括运动模式设计、关节控制、通信模块设计和吸盘足控制等.实验结果证明了所提出方案的可行性.