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Ultrasonic Doppler Vector Speed Sensor for Autonomous Tractors

用于自主拖拉机的超声波多普勒矢量速度传感器

基本信息

批准号：
09556052
负责人：
IMOU Kenji
金额：
$ 3.84万
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：
1997
资助国家：
日本
起止时间：
1997 至 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09556052/
关键词：
autonomous vehicle tractor velocimeter ultrasonic wave ultrasonic Doppler speed sensor 自律走行

项目摘要

The purpose of this study is developing a speed sensor for autonomous tractors. Ultrasonic or microwave Doppler speed sensors are used in autonomous driving systems. However, those sensors were originally intended for tractor performance monitoring. The accuracy of those sensors is not enough for position detection. The authors studied on the error factors of ultrasonic Doppler speed sensor, and developed an accurate speed sensor. Results of the study are summarized as follows,1. Improvements of sensitivity and resolution: For most conventional sensors, it was difficult to measure very low speed or reverse motion. The problem was solved by frequency multiplication of the received signal and mixing with a reference signal in the developed sensor. The sensitivity was also improved using a preamplifier and a tuned amplifier.2. Reduction of the error from the change in reflection angle on the ground: An offset parabolic reflector was designed and attached to the sensor to keep the transmission and received waves in the constant direction. An ultrasonic transmitter and a receiver of relatively low frequency were used for the sensor. Accuracy of the measurement on smooth ground surfaces was improved.3. Comparative test: Test equipment for speed sensors was constructed using a 4m long linear actuator. High accuracy of the developed sensors was confirmed by comparison with commercial sensors.4.Experiments of an autonomous tractor: An autonomous tractor was developed using internal sensors and a GPS. Experiments of autonomous driving were carried out on a horizontal forage farm. In the case of 270m driving at a speed of 0.8m/s, the maximum displacement from the reference line was about 0.5m.

本研究的目的是开发一种用于自动拖拉机的速度传感器。超声波或微波多普勒速度传感器用于自动驾驶系统。然而，这些传感器最初用于拖拉机性能监测。这些传感器的精度不足以进行位置检测。研究了超声波多普勒测速传感器的误差因素，研制了一种高精度测速传感器。研究结果如下：1.灵敏度和分辨率的提高：对于大多数传统传感器来说，很难测量非常低的速度或反向运动。该问题通过对接收信号进行倍频并与所开发的传感器中的参考信号混合来解决。同时，使用了一个调谐放大器和一个调谐放大器，提高了灵敏度.减少地面反射角变化引起的误差：设计了一个偏置抛物面反射器，并将其连接到传感器上，以保持发射和接收波的方向不变。传感器采用超声波发射器和相对低频的接收器。提高了在光滑地面上的测量精度.对比测试：速度传感器的测试设备使用4 m长的线性致动器构造。通过与商业传感器的比较，证实了所开发的传感器的高精度。4.自主拖拉机的实验：使用内部传感器和GPS开发了自主拖拉机。在水平式饲料农场上进行了自动驾驶实验。在以0.8m/s的速度行驶270 m的情况下，距基准线的最大位移约为0.5m。