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transponder of intensity modulated diffuse light for low cost navigation systems

用于低成本导航系统的强度调制漫射光转发器

基本信息

批准号：
14360147
负责人：
IMOU Kenji
金额：
$ 9.22万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2005
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-14360147/
关键词：
Tractor Position detection Navigation Infrared Modulated light Image processing Speed sensor Ultrasonic ナビーション拡散光

项目摘要

This study was conducted for the purpose of producing a low cost navigation system, which is necessary for the autonomous vehicles and precision farming. In this study, high precision ultrasonic speed sensors, range finding systems and movement vector estimation methods using optical flows have been developed.The authors developed an ultrasonic Doppler speed sensor in the previous study. In this project, the accuracy of the speed sensor was improved to conduct stable measurement even in the case of smooth ground. The sensor showed the good results also in farm teats and indoor tests on the model plants. Farther more, the possibility of vector measurement including the sideslip was confirmed.The one directional diffuse light range finder could measure the distance with the standard error of about 3%. However, the omni directional range finder had the phase difference between the directions, which should be compensated. The standard error was 5 % in cloudy condition, but the accuracy was decreased and measurable range was also decreased under the sunshine. The signal processing units including the amplifiers should be improved. The vehicle position measurement was possible using two fixed stations and one on-vehicle unit, but the problem of the temperature drift still remained.Concerning to the movement determination by optical flow, two programs were developed using the Hough transform to decrease the computation time. The computation time for one measurement was considerably improved into about 0.3s, and the average ratio of the positional error to the movement distance was about 5%. The measurable range of the movement distance was about 30 mm in each of the X and Y-directions, which should be improved for the real time measurement.

本研究的目的是生产一种低成本的导航系统，这是必要的自动驾驶汽车和精确农业。本研究发展了高精度超音波速度感测器、测距系统及利用光流法估测运动向量的方法。在本项目中，提高了速度传感器的精度，即使在光滑地面的情况下也能进行稳定的测量。该传感器在田间试验和室内模型植物试验中也显示了良好的效果。进一步验证了考虑侧滑影响的矢量测距的可行性，单方向漫射光测距仪可以实现3%左右的标准误差。但是，全向测距仪存在方向间的相位差，需要进行补偿。在多云条件下，标准误差为5%，但在日照条件下，准确度降低，可测量范围也减小。包括放大器在内的信号处理单元应得到改进。利用两个固定站和一个车载单元实现了车辆位置的测量，但温度漂移问题仍然存在。关于光流运动确定，为了减少计算时间，开发了两个利用Hough变换的程序。一次测量的计算时间被显著地改进为约0.3s，并且位置误差与移动距离的平均比率为约5%。移动距离的可测量范围在X和Y方向中的每一个上都是大约30 mm，这对于真实的时间测量来说应该被改进。