Design of an auditory guidance system for the blind with signal transformation from stereo ultrasonic to binaural audio

We have designed an auditory guidance system for the blind using ultrasonic-to-audio signal transformation. We first investigated the system requirements, and designed a simple but useful portable guidance system for the blind. The system derives visual information using multiple ultrasonic sensors, and transforms it to binaural auditory information using a suitable technique. The user can recognize the position of obstacles and the surrounding environment. The system is composed of two parts. One is a glasses-type system, and the other is a cane-type system with guide wheels. The former functions as an environment sensor, and the latter functions as a clear-path indicator. Wide-beam-angle ultrasonic sensors are used to detect bojects over a broader range. The system is designed as a battery-supplied portable model. Our design is focused on low power consumption, small size, light weight, and easy manipulation.     

移动机器人的多传感器测距系统设计

在移动机器人的路径规划过程中,必须掌握障碍物的距离信息.基于超声波和红外传感器的测距原理,设计了一种移动机器人多传感器测距系统,可测量0～200 cm距离内存在的障碍物,测量误差小于1 %.采用超声波和红外2种传感器组成3组测距采集系统,采集机器人3个不同方位的障碍物信息,解决了单一传感器测距盲区的问题,并详细介绍了该系统的软件和硬件设计.     

The GuideCane-applying mobile robot technologies to assist thevisually impaired

The GuideCane is a device designed to help blind or visually impaired users navigate safely and quickly among obstacles and other hazards. During operation, the user pushes the lightweight GuideCane forward. When the GuideCane's ultrasonic sensors detect an obstacle, the embedded computer determines a suitable direction of motion that steers the GuideCane and the user around it. The steering action results in a very noticeable force felt in the handle, which easily guides the user without any conscious effort on his/her part     

基于GPS定位与超声波导盲拐杖的设计

针对市场上供盲人使用的导盲拐杖结构简单,功能单一,无法实现较好导盲效果的弱点,设计了一款以单片机AT89C52为主控件,具有GPS坐标定位、超声波测障、语音提示等功能的智能拐杖;介绍了智能拐杖的组成结构和工作原理;在分析GPS信号语句格式和处理流程的基础上,设计了硬件电路和实现软件编程;利用超声波发射和接受电路实现了测障报警功能;基于SYN6288语音合成芯片实现定位、时间信息的语音输出功能;有效地实现了导盲拐杖智能化操作和多功能扩展。     

Recovering the sight to blind people in indoor environments with smart technologies

Assistive technologies for blind people are showing a fast growth, providing useful tools to support daily activities and to improve social inclusion. Most of these technologies are mainly focused on helping blind people to navigate and avoid obstacles. Other works emphasize on providing them assistance to recognize their surrounding objects. Very few of them however couple both aspects (i.e., navigation and recognition). With the aim to address the aforesaid needs, we describe in this paper an innovative prototype, which offers the capabilities to (i) move autonomously and to (ii) recognize multiple objects in public indoor environments. It incorporates lightweight hardware components (camera, IMU, and laser sensors), all mounted on a reasonably-sized integrated device to be placed on the chest. It requires the indoor environment to be ‘blind-friendly’, i.e., prior information about it should be prepared and loaded in the system beforehand. Its algorithms are mainly based on advanced computer vision and machine learning approaches. The interaction between the user and the system is performed through speech recognition and synthesis modules. The prototype offers to the user the possibility to (i) walk across the site to reach the desired destination, avoiding static and mobile obstacles, and (ii) ask the system through vocal interaction to list the prominent objects in the user's field of view. We illustrate the performances of the proposed prototype through experiments conducted in a blind-friendly indoor space equipped at our Department premises.     

一种新颖的基于二分法和模糊控制的移动机器人避障系统

针对超声波传感器波束角窄导致移动机器人存在避障盲区的现状,研究了一种新颖的超声波避障系统。该系统采用六个超声波传感器构成特别设计的超声波阵列,实现无盲区检测中大型移动机器人前方及左右两侧障碍物的位置,充分保障运行安全性;同时在避障算法上,采用二分法和模糊控制相结合的控制算法,简化了模糊控制规则使系统具有很好的智能性和实时性,实现了移动机器人选择最佳避障路径并对新增的动态障碍物进行避障。将此避障控制系统应用于移动机器人上,实验结果表明：在未知环境下,实现对移动机器人周边的无盲区检测,并且能够实时根据周围障碍物的动态情况选择最佳避障路径,避免了其它避障控制算法中易出现的误避障和二次避障的情况。     

基于K近邻和动态时间规整算法的盲人物联网手杖系统

针对盲人出行时的安全和监护问题,提出了一种基于机器学习算法的盲人物联网手杖系统的设计,该系统具有避障、定位、报警和通信等多种功能。首先,该系统具有红外线避障和超声波测距避障的基本功能,可以用于盲人日常出行对路况障碍物的检测,并且实时利用语音和电机震动给予提醒;其次,该系统还具有远程通信求助功能,可以向指定号码发送求助短信及电话;同时,系统还加入了全球定位系统（GPS）、加速度计陀螺仪姿态角度解算功能和以K近邻（KNN）和动态时间规整（DTW）算法为基础的异常姿态报警功能,它能将各类信息数据传输至云端服务器存储;最后,采用微信小程序代替原生APP作为监护操作界面,并提供一键报警、天气查询、盲人安全资讯等功能。测试实验结果表明,所提系统的姿态识别成功率达到了86%,正确率比姿态角系统提高将近31%。该盲人物联网手杖系统可以极大地提高盲人出行的安全性,使盲人能够在发生意外时及时求助,实现了对盲人姿态的安全监护和定位监护。     

NavBelt and the Guide-Cane [obstacle-avoidance systems for the blind and visually impaired]

NavBelt and GuideCane are computerized devices based on advanced mobile robotics obstacle-avoidance technologies. NavBelt is worn by the user like a belt and is equipped with an array of ultrasonic sensors. It provides acoustic signals via a set of stereo earphones that guides the user around obstacles or "displays" a virtual acoustic panoramic image of the traveler's surroundings. One limitation of the NavBelt is that it is exceedingly difficult for the user to comprehend the guidance signals in time to allow fast walking. A newer device, called GuideCane, effectively overcomes this problem. The GuideCane uses the same mobile robotics technology as the NavBelt but is a wheeled device pushed ahead of the user via an attached cane. When the GuideCane detects an obstacle, it steers around it. The user immediately feels this steering action and can follow the GuideCane's new path easily without any conscious effort. This article describes the two devices, including the mechanical, electronic, and software components, user-machine interface, and some experimental results.     

Are electronic white canes better than traditional canes? A comparative study with blind and blindfolded participants

Visually impaired individuals often rely on assistive technologies such as white canes for independent navigation. Many electronic enhancements to the traditional white cane have been proposed. However, only a few of these proof-of-concept technologies have been tested with authentic users, as most studies rely on blindfolded non-visually impaired participants or no testing with participants at all. Experiments involving blind users are usually not contrasted with the traditional white cane. This study set out to compare an ultrasound-based electronic cane with a traditional white cane. Moreover, we also compared the performance of a group of visually impaired participants (N = 10) with a group of blindfolded participants without visual impairments (N = 31). The results show that walking speed with the electronic cane is significantly slower compared to the traditional white cane. Moreover, the results show that the performance of the participants without visual impairments is significantly slower than for the visually impaired participants. No significant differences in obstacle detection rates were observed across participant groups and device types for obstacles on the ground, while 79% of the hanging obstacles were detected by the electronic cane. The results of this study thus suggest that electronic canes present only one advantage over the traditional cane, namely in its ability to detect hanging obstacles, at least without prolonged practice. Next, blindfolded participants are insufficient substitutes for blind participants who are expert cane users. The implication of this study is that research into digital white cane enhancements should include blind participants. These participants should be followed over time in longitudinal experiments to document if practice will lead to improvements that surpass the performance achieved with traditional canes.

     

在动态环境中移动机器人导航和避碰的一种新方法

本文提出了基于超声传感器的信息,将改进的栅格 和回归预测法结合起来,应用于具有静态和动态障碍物的动态环境中,移动机器人THMR-Ⅱ 的导航和避碰的一种新方法．对栅格法的改进就是以障碍物为单位记录信息量,结果比原来 以栅格为单位记录的信息量少得多,克服了栅格法中存在环境信息存储量大的问题,提高了 实时性．对回归预测法也作了改进,并把它们结合起来,在求得最佳候选扇区后,使移动机 器人躲避了静态和动态障碍物,实现了导航,最终到达目标．通过三种仿真实验,结果表明 作者提出的方法是正确和有效的．     

Obstacle avoidance algorithm for visual navigation using ultrasonic sensors and a CCD camera

An obstacle-avoidance algorithm is presented for autonomous mobile robots equipped with a CCD camera and ultrasonic sensors. This approach uses segmentation techniques to segregate the floor from other fixtures, and measurement techniques to measure the distance between the mobile robot and any obstacles. It uses a simple computation for the selection of a threshold value. This approach also uses a cost function, which is combined with image information, distance information, and a weight factor, to find an obstacle-free path. This algorithm, which uses a CCD camera and ultrasonic sensors, can be used for cases including shadow regions, and obstacles in visual navigation and in various lighting conditions. This work was presented in part at the 7th International Symposium on Artificial Life and Robotics, Oita, Japan, January 16–18, 2002     

路口导盲及马路障碍物检测提醒系统的设计

为了帮助盲人自行通过路口并检测提醒盲人道路上的障碍物情况,设计制作了一个路口导盲及马路障碍物检测提醒系统,该系统通过超声波模块检测障碍物信息,通过方向传感器模块和无线通信模块获取盲人的朝向信息和盲人当前朝向路口的红绿灯信息,并利用震动模块和语音模块对盲人进行提醒。最后制作出系统实物并模拟验证了该系统是有效可行的。     

Non-visual navigation of spreadsheets

The problem of non-visual navigation of the information in Excel? spreadsheet is that using current technologies, no overview is available for the user about different components found in the spreadsheet. Several attributes associated with spreadsheets make them not easy to navigate by individuals who are blind. The large amount of information stored in the spreadsheet, the multi-dimensional nature of the contents, and the several features it includes cannot be readily linearized by a screen reader or Braille display (e.g., charts and tables). A user-centered design paradigm is followed to build an accessible system for non-visual navigation of Microsoft Excel? spreadsheet. The proposed system provides the user with a hierarchical overview of the navigated components in an Excel? spreadsheet. The system is multi-modal, and it provides the user with different navigation and reading modes for the non-visual navigation of a spreadsheet. This will help the users in adapting the non-visual navigation according to the task the user needs to accomplish.     

自主湖水环境监测船的运动控制系统设计

设计自主湖水环境监测船的运动控制系统,包括由GPS和电子罗盘构成的导航系统、超声传感器避障系统、太阳能和蓄电池配合的自主能源供给系统。采用超声、红外传感器和机械卡环设计自动泊位装置。基于坐标系变换,建立自主船的运动学模型。针对双电机的转速控制,设计实现三层递阶控制器及滑膜变结构转速控制算法。实验结果表明,滑膜控制能较好地排除水流速度的突变干扰,差动转向平稳,自主船可实现自动泊位和能源自给,运动控制系统稳定,速度响应小于4 s,大角度转向响应小于13 s。     

基于模糊控制的盲人避障系统设计

文章基于多个超声波传感器对地面信息的采集,利用模糊控制算法将采集的信息转化为指引盲人避障的语音提示。该系统采用超低功耗的MSP430单片机作为主控单元,外围设计了五路超声波传感器采集全方位的路面信息。通过分析路面信息,从而给出盲人前进方向以及前进的速度语音提示,实现盲人避障的功能。     

一种多传感器智能导盲装置的设计

为提高盲人出行方便度,设计了一种多传感器智能导盲装置,采用6对超声波传感器分上下两组探测障碍物,对多种数据源、多个传感器的采集信息进行融合处理,借助LM35温度传感器实现测量准确度的提高,并基于蓝牙技术实现了无线语音分段提示.实验结果表明该装置可以感测到的有效距离约为30～4000mm,实际值相对误差控制在2与％以内,满足盲人日常行为中的使用需求.     

基于ARM的智能导航盲杖系统设计

针对目前市场上盲用导航产品的不足,采用基于ARM11的S3C6410微处理器和基于Win CE软件,设计了智能导航盲杖系统.通过GPS模块,该系统可以提供盲用定位与导航功能.利用超声波测障模块,系统能够实现一定范围内的障碍物告警,极大地解决了盲人独立出行困难的问题.     

智能穿戴超声波测距可定位导盲腰带研究与设计

采用超声波原理,以STC89C52单片机作为主控核心,设计一款智能穿戴超声波测距可定位导盲腰带。该装置可以给处于行走状态的盲人进行道路障碍的实时探测,障碍物的实时距离信息以语音播报方式实现传送,使盲人获取其周围环境情况,并通过附带GPS定位、GSM通信功能保障盲人出行安全。此腰带设计采用的设备成本较低并易于批量生产,测距误差小,作为盲人出行的辅助工具有较高的实用价值。     

Reactive navigation in dynamic environment using a multisensorpredictor

A reactive navigation system for an autonomous mobile robot in unstructured dynamic environments is presented. The motion of moving obstacles is estimated for robot motion planning and obstacle avoidance. A multisensor-based obstacle predictor is utilized to obtain obstacle-motion information. Sensory data from a CCD camera and multiple ultrasonic range finders are combined to predict obstacle positions at the next sampling instant. A neural network, which is trained off-line, provides the desired prediction on-line in real time. The predicted obstacle configuration is employed by the proposed virtual force based navigation method to prevent collision with moving obstacles. Simulation results are presented to verify the effectiveness of the proposed navigation system in an environment with multiple mobile robots or moving objects. This system was implemented and tested on an experimental mobile robot at our laboratory. Navigation results in real environment are presented and analyzed.     

Fuzzy logic techniques for navigation of several mobile robots

In this paper, navigation techniques for several mobile robots as many as one thousand robots using fuzzy logic are investigated in a totally unknown environment. Fuzzy logic controllers (FLC) using different membership functions are developed and used to navigate mobile robots. First a fuzzy controller has been used with four types of input members, two types of output members and three parameters each. Next two types of fuzzy controllers have been developed having same input members and output members with five parameters each. Each robot has an array of ultrasonic sensors for measuring the distances of obstacles around it and an infrared sensor for detecting the bearing of the target. These techniques have been demonstrated in various exercises, which depicts that the robots are able to avoid obstacles as well as negotiate the dead ends and reach the targets efficiently. Amongst the techniques developed, FLC having Gaussian membership function is found to be most efficient for mobile robots navigation.