面向机器人运动跟踪的电磁定位系统

电磁定位具有精度高、速度快和易实现等优点,所以对手术、室内和室外机器人跟踪是一个良好的选择。电磁定位以交变电磁信号作为源信号。交变的电流信号激励发射线圈（信号激励部件）在空间中产生交变的电磁场,感应线圈（信号感应部件）在交变的电磁场中输出频率相同的信号。根据输出信号的幅值和相位信息,我们可以计算出感应线圈相对于发射线圈的位置和方向信息。本文面向机器人定位跟踪,介绍电磁定位系统的原理与实现,包括磁场模型、电磁定位算法与系统软硬件的搭建与实验。本文介绍两种不同的激励模式,分别为分时激励3轴正交发射线圈模式与同时激励2轴正交发射线圈模式,两种模式中的感应线圈均采用3轴正交线圈。实验结果表明,定位系统可以达到1 mm的定位精度。     

用于骨科手术机器人的电磁定位方法

针对计算机辅助骨科手术,提出了基于磁偶极子模型的电磁定位方法.该方法以交流线圈为发射源,由电磁定律,接收线圈会产生感应电动势.由磁偶极子模型计算出磁场的空间分布,推导出包含目标位置和方向信息的方程组,利用非线性算法来解方程,从而得到一个稳定的、实时的定位方法.通过仿真验证该模型所需的方程数,实验结果表明该方法是有效的,...     

虚拟现实系统中六自由度电磁跟踪算法的改进

详细讨论了用于虚拟现实的直流式六自由度电磁跟踪系统的传统定位算法的一个改进。本算法中,以正交的三轴发射源和两轴轴探测器作为传感器定位器件,替代了以往的三轴发射源和三轴轴探测器。算法中以脉冲直流信号驱动发射源三轴分时发射,同时接收器两轴探测到相应的三组电磁信号和一个空驱动时间段内的环境磁场信号,通过该过程中获得的包括环境磁场信息在内的９个数据确定了被测对象的方位（位置和姿态）。     

平面电磁定位跟踪系统

通电线圈常被用作电磁定位装置收发器,应用在移动目标或机器人的实时位置跟踪任务中。系统的激励线圈磁场分布模型、信号发生提取电路和定位算法软件都影响系统定位的精度。本文采用磁偶极子模型,针对平面移动目标跟踪定位的特殊情况,设计基于嵌入式系统ARM(STM32)的大范围平面运动的定位系统。系统采用单发射线圈三接收线圈方案,及一种解析法求解目标位置的算法,可以定位离信号源数米范围内的移动目标。从仿真与实验中验证其可以很好的求解平面一类移动目标位置,平均误差在10 cm内。系统的定位精度满足大部分定位需要。     

基于相位自适应的双线圈无线能量传输系统设计

单线圈磁共振耦合无线能量传输系统要求发射端和接收端对齐,限制了系统的实际应用.多线圈发射系统通过配置线圈阵列,利用模拟波束成形算法,改变电压和电流的相对相位,从而控制磁场波束在接收端叠加的相位,实现能量最大传输.设计了一种基于相位控制的无线能量传输系统,通过自适应算法改变发射波形的相位,使接收线圈获得较高的能量.系统简化了功放的设计,实现了接收端全方向高效的能量接收.测试结果表明:系统可以稳定高效地运行.     

电磁定位系统中发射线圈半径优化设计

电磁定位系统中通常以多匝线圈来作为发射装置,以磁偶极子定位模型为基础来实现电磁定位技术.然而传统计算电磁定位的方式,只是将多匝线圈的半径简单归一化为一常数r,而忽视了线圈与线圈之间的差异性.对多匝发射线圈建立起多磁偶板子模型,并利用该模型来修正传统计算公式中多匝发射线圈的半径.仿真实验计算多匝线圈的磁感应强度表明,在环数一定的情况下,随着层数的增加,优化后的效果越明显,对计算接收线圈的感应电动势更为准确.     

单级感应线圈炮最佳初始位置仿真研究

在单级感应线圈炮的发射过程中，影响电磁发射效率的因素有很多。弹丸初始位置就是其中之一。以驱动线圈和弹丸的初始中心距为变量。以弹丸所能达到的最大速度为目标函数。采用轴对称线圈磁场的数值计算方法和微分方程的前向差分法。对单级感应线圈炮系统进行了仿真研究；研究的结果表明，对于给定的单级感应线圈炮系统。确实存在一个最佳的初始位置，使得弹丸的速度能达到最大。并且，通过仿真计算，得出了该最佳初始位置。这为以后的工程实践提供了理论参考。     

基于磁共振无线电能传输系统中三种结构线圈空间磁场分布研究

在磁耦合谐振无线电能传输研究中,采用何种线圈结构能使传输距离达到最远目前还没有一个定论。根据毕奥-萨伐尔定律理论推导了矩形、平面型和圆柱型等三种螺旋线圈的空间磁场分布表达式;提出一种求解磁场空间分布的新算法,并对结果进行了验证。绘出三种线圈在最大半径、匝间距及匝数一致时的空间分布三维图;比较三种不同结构线圈的空间磁场分布规律,为无线电能传输研究中采取何种结构线圈作为系统发送、接收线圈提供理论参考。     

一种磁聚焦技术在磁耦合无线电能传输中的应用

磁耦合谐振式无线电能传输中单发射机功率受限,接收端感应电压难以取得显著提升。可以采用多发射机电路模型,多个发射器同时将功率无线传输到单个接收器。其中发射端采用多线圈阵列模型,与单线圈接收机耦合“共振”传输能量,形成MISO(Multiple Input Single Output)系统。采用磁聚焦技术分析线圈电流组合对系统输出的影响,通过改进粒子群算法(IPSO)求解最优输入解,得到的磁场聚焦性能更好,能量分布更加集中。实验证明,模型可以有效提升接收增益,降低系统损耗。     

基于平面微带线圈无线电力传输效率研究

磁耦合谐振式无线能量传输技术主要是由谐振频率相同的发射线圈和接收线圈构成,在近距离范围内,当工作频率等于发射和接收线圈的谐振频率,线圈之间通过磁场耦合谐振的作用完成能量的传输,是电力传输领域的一个全新的技术方向。在本文中,磁耦合谐振无线能量传输系统由印制在两块FR-4基板上的微带线圈组成,且谐振频率为13.56 MHz的微带线圈分别印制在每块基板的两面。根据FITD(Finite-Integral Time-Domain)算法对磁耦合谐振无线能量传输系统模型进行仿真与分析,在13.56 MHZ的频率下,磁耦合谐振无线能量传输系统的传输效率最大可达到64%。在构建无线能量传输平台后,通过实验测得传输效率可以达到54%。     

Positioning of a mobile robot based on odometry and a new ultrasonic LPS

Odometry is a method that calculates the position and heading angle of a mobile robot using encoders attached to the wheels of the robot. Errors in the position and heading angle in odometry continuously increase as the operating time and moving distance increase. The solution to overcome these accumulated errors is to periodically compensate with the external absolute position information. An ultrasonic local positioning system (LPS) consists of multiple ultrasonic transmitters located in the environment and an ultrasonic receiver. In this study, ultrasonic transmitters are in a line at one side, and four transmitters are grouped for a coverage area. In order to measure the time of flights (TOFs) for an ultrasonic signal, the receiver predicted the transmitted time from each transmitter using a hyperbolic model. Four transmitters emit ultrasonic signals sequentially, and then the receiver calculates the position using the present measured distance and the pre-measured distance. In order to extend the distance that is measured, the receiver collects the ultrasonic signal and executes cross correlation with a sinusoidal signal. The measured distance data of the previous step causes the position error. This error is compensated for by the predicted distance data using a bilinear interpolation method. An extended Kalman filter is designed to combine odometry, a compass sensor, and an ultrasonic LPS. The proposed system provides reliable and accurate position and heading information, regardless of the operating time and moving distance.     

Wireless magnetic resonant energy transfer system based on micro 3D flexible MEMS Litz coils

Wireless magnetic resonant energy transfer system shows more superiority in energy transfer efficiency and relative position parameters than that of inductive coupling system. It has been recognized as the best power supply method for implantable medical devices. The dimension and performance of the resonant coil is the key point that has great effect on the transfer efficiency and implantable applications. In this paper, high Q flexible planar and roll Litz coil is designed and implemented for the wireless energy transfer system. L and Q for 3D Litz coil is calculated and compared by theoretical model. The roll-Litz coil shows better performance in L and Q with smaller size comparing with the planar-Litz coil. Wireless energy transfer system based on two and four resonant coils is build up. The experimental results show that the energy transfer efficiency is improved by using the high Q 3D Litz coils. What’s more the roll-Litz four coil system shows priority in higher transfer efficiency with smaller size comparing with planar-Litz coil system. The efficiency of four-coil transfer system based on roll-Litz coils gets 48 % higher than the two-coil system with 1.0 cm transfer distance, and 10 % higher than the four-coil transfer system based on planar-Litz coils with 1.5 cm transfer distance.     

三维梯度矢量瞬变电磁仪的建模及其仪器研制

为了探索和解决瞬变电磁物探在空间信息解析方面存在多解性问题,提出三分量梯度矢量瞬变电磁法模型和仪器方案,解决瞬变电磁探测深度的计算依赖于地层电导率和磁导率的问题。新型模型和仪器采集探测点的二次场三分量数据,得到其梯度矢量方向和大小,结合测点之间的距离和空间三角函数关系,计算出探测方向中低阻体的方位和距离。新型瞬变电磁仪在煤矿工作面的超前探测得到试用,验证预期效果,推广到物探工程应用中。     

The localization of a mobile robot using a pseudolite ultrasonic system and a dead reckoning integrated system

In this paper, an integration system is proposed to improve the positioning performance of a mobile robot by fusing a Pseudolite Ultrasonic System (PUS), an absolute position measurement system using direct ultrasonic waves, with a Dead Reckoning (DR) odometer. As an integration algorithm of the absolute position measurement system and DR, two methods are proposed. In the loosely coupled method, the PUS and the DR calculate the position independently and a Kalman filter estimates the position using position information from the PUS and the DR. In the tightly coupled method, the PUS provides the distance between the ultrasonic transmitters and receivers without calculating the position directly and the DR provides the translational and rotational displacement of the mobile robot. The Kalman filter then estimates the position using information from the PUS and the DR. In addition, to improve the positioning performance in case the line-of-sight (LOS) between the ultrasonic transmitter and receiver is blocked due to obstacles, a positioning failure detection algorithm and reckoning methods are proposed. The positioning performances of the proposed PUS/DR integrated systems and the validity of the positioning failure detection algorithm are verified and evaluated by experiments.     

Concurrent localization of multiple robots

A concurrent localization method for multiple robots using ultrasonic beacons is proposed. This method provides a high-accuracy solution using only low-price sensors. To measure the distance of a mobile robot from a beacon at a known position, the mobile robot alerts one beacon to send out an ultrasonic signal to measure the traveling time from the beacon to the mobile robot. When multiple robots requiring localization are moving in the same block, it is necessary to have a schedule to choose the measuring sequence in order to overcome constant ultrasonic signal interference among robots. However, the increased time delay needed to estimate the positions of multiple robots degrades the localization accuracy. To solve this problem, we propose an efficient localization algorithm for multiple robots, where the robots are in groups of one master robot and several slave robots. In this method, when a master robot calls a beacon, all the group robots simultaneously receive an identical ultrasonic signal to estimate their positions. The effectiveness of the proposed algorithm has been verified through experiments.     

Application of Localization Based on the DC Magnetic Field that Occurs in the Environment on Wheel-Type Mobile Agricultural Robots

A wheel-type mobile robot is simply able to localize with odometry. However, for mobile agricultural robots, it is necessary to consider that the environment is uneven terrain. Therefore, odometry is unreliable and it is necessary to augment the odometry by measuring the position of the robot relative to known objects in the environments. This paper describes the application of localization based on the DC magnetic field that occurs in the environment on mobile agricultural robots. In this research, a magnetic sensor is applied to scan the DC magnetic field to build a magnetic database. The robot localizes by matching magnetic sensor readings against the magnetic database. The experimental results indicate that the robot is able to localize accurately with the proposed method and the cumulative error can be eliminated by applying the localization results to compensate for the odometry.     

一种新的基于RFID的室内移动机器人自定位方法研究

针对室内移动机器人自定位算法定位精度不高、定位误差存在波动的问题,提出了一种RTFL(RFID tag floor based localization)定位算法与RSSI定位算法相结合的室内移动机器人自定位方法。由RTFL定位算法给定机器人位置估算初值和机器人所在的范围,然后通过基于RSSI的机器人自定位系统进行机器人位置的进一步精确定位。求解过程中,通过遗传算法求解极大似然方程组,并且提出了染色体的筛选和剔除策略。仿真实验结果表明：该方法在有效的时间内完成定位,平均定位误差为0.1572m,与传统的改进方法0.33214m的定位误差相比,降低了近一倍。并且新方法受环境影响较小,鲁棒性较好,能够很好的满足室内移动机器人的定位要求。     

基于信标导引的目标方位估计方法

基于准确测量目标方位进而快速实施救援的需要,采用无线信标、电子磁罗盘和卫导组合技术,设计了一种集发射端信标信号全向发射、接收端信标信号定向接收、数字化声谱处理、干扰野值剔除、信标方位精确测量、信标距离概略估计等功能于一体的户外搜救导引系统。并研究分析了一种基于信标导引的目标方位估计方法,该方法通过接收远程、配属在合作目标端信标发射的声波脉冲信号并进行FFT变换,进而通过分析频谱的特征参数来对目标的方位进行准确测量,对目标的距离进行概略估计;测试结果表明该方法比较适合郊区和城市等户外环境中对合作目标进行快速探测搜救和远程监视的需要。