Using mobile robots to harvest data from sensor fields - [wireless communications in networked robotics]

We explore synergies among mobile robots and wireless sensor networks in environmental monitoring through a system in which robotic data mules collect measurements gathered by sensing nodes. A proof-of-concept implementation demonstrates that this approach significantly increases the lifetime of the system by conserving energy that the sensing nodes otherwise would use for communication.     

机器人激光扫描系统现场标定技术

针对机器人激光 扫描系统现场标定问题,提出了一种基于交比不变性的线结构光传感器标定方法,允许平 面参 照物在传感器测量空间中自由移动,通过摄像机拍摄多幅平面参照物的图像即可对光平面进 行标定;同时, 提出一种定点变位姿的机器人手眼关系标定方法,采用一个直径已知的标准球作为手眼标定 参照物,控制 机器人分别以纯平移运动和变姿态运动的方式带动视觉传感器对标准球的球心坐标进行测量 ,根据固定点 约束标定手眼关系。实验结果表明,本文标定方法有效、快速,可以用于机器人激光扫 描系统现场标定。     

Bio-Inspired Large-Area Soft Sensing Skins to Measure UAV Wing Deformation in Flight

Biological organisms demonstrate remarkable agility in complex environments, especially in comparison to engineered robotic systems. In part, this is due to an organism's ability to detect disturbances and react to them quickly. To address the challenge of quickly sensing these same disturbances in robotic systems, this study proposes and demonstrates large-area soft sensing skins designed to sense disturbances on unmanned aerial vehicles (UAVs) in flight. These skins are enabled by high-resolution soft strain sensors embedded into a large-area skin through a modular molding process that spans feature sizes from tens of microns to 0.675 m. The electronics of the sensing system enable the soft skins to be sampled fast enough to capture dynamic loads on a wing. Overall, the large-area soft sensing skin demonstrates high sensitivity, mechanical robustness, and consistent sensor readings across static and dynamic tests. The use of the soft sensing skin during UAV flight demonstrates that the sensing skin can capture relevant flight dynamics on small UAVs. These results pave the way to large-area soft sensing skins for fast and robust control of a wide variety of robotic systems.     

Integration of task scheduling, action planning, and control inrobotic manufacturing systems

This paper presents a novel approach for solving a challenging problem in the intelligent control of robotic manufacturing systems, i.e., the integration of low-level system sensing and control with high-level system behavior and perception. First, a newly developed event-based planning and control method will be introduced. It will then be extended to a robotic manufacturing system via a hybrid system approach. The tasks of a robotic manufacturing system usually consist of multiple segments of robotic actions, which involve both continuous and discrete types of actions. The max-plus algebra model has been proposed to model such a system. Combined with the event-based planning and control methods, both discrete and continuous actions can be planned and controlled based on the max-plus algebra model. More important, the interactions between discrete and continuous actions can be formulated analytically. A typical parts-sorting task in a robotic manufacturing system is used to illustrate the proposed approach. The experimental results clearly demonstrate the advantages of this method     

Determination and comparison of surface mount component rework cycle times of manual and fully automated robotic rework stations for rework technology selection

The aim of this paper is to provide a complete decision framework to find out when it is appropriate to use an automated robotic rework station for surface mount (SM) component rework. For this purpose, the results of the performance tests on the cell and manual rework cycle times (RCTs) have been determined using experimental studies. These are followed by the comparison of the experimental results, rework effectiveness, parametric rework cycle determination and overall rework cost studies. As a conclusion, a framework has been suggested by comparing automated versus manual rework stations to find out when it is appropriate to use an automated robotic rework cell. Furthermore, it provides manual and automated RCTs for SM components.     

一种表征EDFA放大宽谱光源的噪声估测方法

光纤放大器作为分布式光纤传感系统实现超长距离、超低损耗传输必不可少的光学器件,其噪声特性对于系统整体性能有着至关重要的影响。微分干涉型分布式光纤传感系统中必须使用宽谱光源,同时探测终端也需采用宽谱探测,因此研究EDFA在宽光谱系统中的噪声对于传感系统整体性能的提升有着重要意义。文中研究了EDFA增益对宽谱光源波长与功率的响应关系,得出了可描述这一关系的增益响应曲线,并依此提出了一种可表征EDFA放大宽谱光源的噪声的估测方法,总结了EDFA放大宽谱光源时的噪声规律。     

An intelligent robotic system for rehabilitation of joints andestimation of body segment parameters

An an application of robotics in physical rehabilitation therapy, a robotic system consisting of two planar robot arms, each with two degrees of freedom, is considered. This robotic system, when coupled across a human joint, provides a vehicle for rehabilitation of the joint following surgery or trauma. A novel approach for estimation of body segment parameters is formulated that uses state and output information from the robot system to improve these estimates. In addition, redundant sensors are used to improve the accuracy of the estimates. The dynamic equations for a single robot arm are provided and the system is simulated. Therapeutic applications of the robotic system are discussed and the sensitivity of the measured forces with respect to the robot arm joint angles is studied in order to find an optimum orientation of the system for the best possible estimation. The application of this system to both rehabilitation and sports medicine is also discussed     

Implementation of vision-based planar grasp planning

This research describes the implementation of a vision-based algorithm that is capable of rapidly determining robotic grasp points for planar objects. A representation of the target and a quadtree expansion generate candidate grasps that are compared using a cost function. The approach returns the first acceptable grasp point at a given tree resolution. The system has an execution time on the order of seconds and it is suitable for a large number of planar or near planar objects     

A MULTI-RESOLUTION SPECTRUM SENSING （MRSS） SCHEME UNDER MEASUREMENT-BASED CHANNEL MODELS IN COGNITIVE RADIO

Spectrum sensing is one of the key technologies in Cognitive Radios (CRs). Previous works are accomplished under simple channel models, which may lead to unreliable results when it applied to the over-the-air systems. In this paper, we investigate the performance of a Multi-Resolution Spectrum Sensing (MRSS) algorithm under measurement-based channel models in China. MRSS is a wavelet based algorithm which is suitable for non-stationary, wideband signal analysis. Using statistical modeling, measurement-based channel models are presented under typical urban and suburban scenarios in Shanghai, China. Then, the performance of the MRSS algorithm is evaluated under the measurement-based channel models. Simulation results show that, using MRSS, the performance is always better in the scenarios where Line-Of-Sight (LOS) path exist; also, in LOS scenarios, rich scattering effect helps to increase the performance.     

A mechatronic approach for robotic deburring

This paper deals with the implementation of a mechatronic methodology for the robotic deburring of planar workpieces with an unknown shape performed by an industrial manipulator. The approach is based on the use of a hybrid force/velocity control law and on a correlated suitable design of the deburring tool. Experimental results, obtained with a two degrees-of-freedom SCARA industrial robot manipulator, show the effectiveness of the method.     

基于CFR虚拟阵列天线的AOA室内定位

准确地估计信号的到达角（Angle Of Arrival,AOA）为实现在室内高精度定位提供了可能,为了能够准确地估计室内多径信号的AOA,并提取出直射路径的AOA信息进行定位,本文提出一种利用信道频率响应信息（Channel Frequency Response,CFR）扩展阵列天线的亚米级室内定位系统.首先,采集CFR信息进行AOA和信号到达时间（Time Of Arrival,TOA）的联合估计;其次,提出了一种基于AOA和TOA二维聚类信息的直射路径识别算法;另外,还提出了可视环境（Line Of Sight,LOS）以及非可视环境（Non Line Of Sight,NLOS）的识别算法,可以准确的判断出当前接收机相对发射机是处于LOS还是NLOS环境;最后,利用现有的三天线Wi-Fi设备在室内进行了测角以及定位测试,实验结果表明本文提出的定位系统在室内LOS和NLOS环境下分别可以达到中值误差为0.8m,1.3m的定位精度,可用于室内高精度定位.     

Hybrid TOA/AOA estimation error test and non‐line of sight identification in wireless location

In this paper, a modified time‐of‐arrival (TOA) estimation error test and a hybrid time‐of‐arrival/angle‐of‐arrival (TOA/AOA) estimation error test for identification of line of sight (LOS) base stations (BSs) are proposed. The proposed schemes aim to improve the location accuracy of wireless location systems suffering from the non‐line of sight (NLOS) propagation errors. The modified TOA‐based estimation error test is considered a straightforward approach in identifying the LOS‐BS set when the number of LOS BSs is greater than or equal to three. When both TOA and AOA metrics are available, hybrid TOA/AOA squares of normalized estimation errors are formulated by adopting the approximate maximum likelihood (AML) estimation. The proposed hybrid estimation error test scheme is capable of identifying the LOS/NLOS status of each BS, and performing location estimation in the situation where only two LOS BSs exist. Simulation results show that the proposed schemes are capable of correctly identifying the LOS BSs and improving the overall location accuracy. Copyright © 2009 John Wiley & Sons, Ltd.     

Set-based collision avoidance applications to robotic systems

A robotic system can consist of a single or multiple agents with a fixed or mobile base, with full or under-actuation, and possibly redundancy. Collision avoidance is a crucial task for any robotic system and is necessary to ensure safe operation. In this paper, we use a set-based approach to ensure collision avoidance as a high-priority task of a robotic system while simultaneously defining one or more tasks for the system to achieve. The set-based approach is highly generic and flexible, and we present theoretical results, practical implementation and experimental results of the approach applied to a redundant, fully actuated robot manipulator, a full-scale underactuated surface vessel and a multi-agent system of unicycles.     

偏轴反射镜平台视轴稳定技术及建模分析

常规反射镜平台采用方位/俯仰型两框架结构形式,探测器视轴平行于外框架旋转轴。区别于常规反射镜平台,偏轴反射镜平台不再遵循探测器视轴与外框架旋转轴平行的原则,其视轴角速度具有强耦合和非线性的特点。主要研究了这类偏轴反射镜平台的运动学、动力学建模和视轴稳定机理。首先,采用虚拟整体稳定平台技术推导平台运动学方程,并确定了虚拟平台框架类型的选取原则。在此基础上推导了完整的视轴坐标系动力学模型。然后,对载体运动耦合机制进行了分析并给出了控制框图。最后,对视轴运动特性进行仿真分析。仿真结果表明,该平台在视轴指向、力矩耦合等方面具有不同于常规反射镜平台的特性,且由视轴运动非线性引起的视轴交叉耦合力矩大于惯量耦合力矩。     

A foot-wearable interface for locomotion mode recognition based on discrete contact force distribution

The knowledge of plantar pressure distribution is important in understanding human locomotion activities, and its integration with robotic assistive devices is an important potential application. In this paper, we aim to explore the potential of using discrete contact force distribution signals for locomotion mode recognition. A foot-wearable interface comprising a pair of sensing insoles, each with four sensors at selected locations, has been designed to record discrete contact forces during locomotion. Based on the information of discrete contact force distribution, we present a locomotion mode recognition strategy with decision tree and linear discriminant analysis classifiers. To verify the measurement performance of the sensing system, experiments are carried out to investigate the system stability in long term working conditions and its adaptation to different ground surfaces. To evaluate whether discrete contact force signals can be used for locomotion mode recognition, five able-bodied subjects and one amputee subject are recruited and asked to perform six types of locomotion tasks. With the proposed recognition strategy, reliable recognition performance is obtained. The average classification accuracy is 98.8% ± 0.5% for able-bodied subjects and 98.4% for the amputee subject, which is comparable to those obtained from systems based on other sensors. These experimental results indicate that monitoring of discrete contact force distribution is valuable for locomotion mode recognition. Its use can be combined with other sensing systems to achieve better performance of locomotion mode recognition for intelligent assistive device control.     

Multibeam Selection for Indoor MIMO Systems: Two Cases of Study

The performance of multiple-input multiple-output (MIMO) systems using beam selection is investigated in this paper. Based on the results of a channel sounding campaign carried out at the University of Manitoba for line-of-sight (LOS) and non-line-of-sight (NLOS) scenarios, it was possible to contrast the results of transmitter, receiver and joint beam selection in rich scattering environments. The channel was characterized in the 1-2.4 GHz frequency band with a multipath delay resolution better than 5.8 ns. The beam selection was performed by exhaustive search method. The results led us to important conclusions regarding the beam selection procedure and its potential to improve the indoor channel capacity. In LOS, the single input single output (SISO) system that favours the maximum power direction of arrival (DOA) maximizes the capacity. Capacity improvements are observed by increasing the number of receiver beams (RBs) only at high signal-to-noise ratios (SNRs) for omnidirectional transmission. The best performance in transmitter beam selection in LOS is observed by increasing the number of transmitter beams (TBs) for high SNRs. In the case of NLOS, the capacity performance is improved when more than a single beam is used in either, transmitter or receiver side. The joint transmitter-receiver beam selection exhibits best capacity performance only for large SNRs in LOS while the SISO systems outperforms any joint beam selection alternative for low SNRs. In contrast, in NLOS environments, the use of joint beam selection shows a constant capacity performance improvement starting from lower SNR than in the LOS case     

Online electromyographic control of a robotic prosthesis

This paper presents a two-part study investigating the use of forearm surface electromyographic (EMG) signals for real-time control of a robotic arm. In the first part of the study, we explore and extend current classification-based paradigms for myoelectric control to obtain high accuracy (92-98%) on an eight-class offline classification problem, with up to 16 classifications/s. This offline study suggested that a high degree of control could be achieved with very little training time (under 10 min). The second part of this paper describes the design of an online control system for a robotic arm with 4 degrees of freedom. We evaluated the performance of the EMG-based real-time control system by comparing it with a keyboard-control baseline in a three-subject study for a variety of complex tasks.     

Influence of an Optimized Thermoelectric Generator on the Back Pressure of the Subsequent Exhaust Gas System of a Vehicle

Numerous research projects in automotive engineering focus on the industrialization of the thermoelectric generator (TEG). The development and the implementation of thermoelectric systems into the vehicle environment are commonly supported by virtual design activities. In this paper a customized simulation architecture is presented that includes almost all vehicle parts which are influenced by the TEG (overall system simulation) but is nevertheless capable of real-time use. Moreover, an optimized planar TEG with minimum nominal power output of about 580 W and pressure loss at nominal conditions of 10 mbar, synthesized using the overall system simulation, and the overall system simulation itself are used to answer a generally neglected question: What influence does the position of a TEG have on the back pressure of the subsequent exhaust gas system of the vehicle? It is found that the influence of the TEG on the muffler is low, but the catalytic converter is strongly influenced. It is shown that the TEG can reduce the back pressure of an exhaust gas system so much that its overall back pressure is less than the back pressure of a standard exhaust gas system.     

An Intelligent Robotic System Capable of Sensing and Describing Objects Based on Bimodal,Self-Powered Flexible Sensors

This study presents an intelligent soft robotic system capable of perceiving, describing, and sorting objects based on their physical properties. This work introduces a bimodal self-powered flexible sensor (BSFS) based on the triboelectric nanogenerator and giant magnetoelastic effect. The BSFS features a simplified structure comprising a magnetoelastic conductive film and a packaged liquid metal coil. The BSFS can precisely detect and distinguish touchless and tactile models, with a response time of 10 ms. By seamlessly integrating the BSFSs into the soft fingers, this study realizes an anthropomorphic soft robotic hand with remarkable multimodal perception capabilities. The touchless signals provide valuable insights into object shape and material composition, while the tactile signals offer precise information regarding surface roughness. Utilizing a convolutional neural network (CNN), this study integrates all sensing information, resulting in an intelligent soft robotic system that accurately describes objects based on their physical properties, including materials, surface roughness, and shapes, with an accuracy rate of up to 97%. This study may lay a robotic foundation for the hardware of the general artificial intelligence with capacities to interpret and interact with the physical world, which also serves as an interface between artificial intelligence and soft robots.     

An experimental study of planar impact of a robot manipulator

An experimental study of planar impact of a robot manipulator with a stationary rigid surface is presented. Using the data collected from a series of experiments, this paper investigates the post-impact behavior for different pre-impact conditions such as the configuration of the robot, the angle and the velocity of impact. A better understanding of the post-impact behavior for various pre-impact conditions can lead to improved control strategies during impacts in robotic manipulation. Potential applications of this study include robotic assembly and contact tasks. Further, this study could be seen as a preliminary experimental work on impact of general kinematic chains.