Navigation of an Autonomous Tractor for a Row-Type Tree Plantation Using a Laser Range Finder—Development of a Point-to-Go Algorithm

Pawin Thanpattranon,Tofael Ahamed,Tomohiro Takigawa

doi:10.3390/robotics4030341

Pawin Thanpattranon, Tofael Ahamed + Show 1 more

Open Access

https://doi.org/10.3390/robotics4030341

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Journal: Robotics	Publication Date: Sep 7, 2015
Citations: 31	License type: CC BY 4.0

Affiliation: University of Tsukuba

Abstract

It is challenging to develop a control algorithm that uses only one sensor to guide an autonomous vehicle. The objective of this research was to develop a control algorithm with a single sensor for an autonomous agricultural vehicle that could identify landmarks in the row-type plantation environment and navigate a vehicle to a point-to-go target location through the plantation. To enable such a navigation system for the plantation system, a laser range finder (LRF) was used as a single sensor to detect objects and navigate a full-size autonomous agricultural tractor. The LRF was used to control the tractor as it followed a path, and landmarks were detected “on-the-go” in real time. The landmarks were selected based on data for their distances calculated by comparison with the surrounding objects. Once the landmarks were selected, a target point was calculated from the landmarks, and the tractor was navigated toward the target. Navigation experiments were successfully conducted on the selected paths without colliding with the surrounding objects. A real time kinematic global positioning system (RTK GPS) was used to compare the positioning between the autonomous control and manual control. The results of this study showed that this control system could navigate the autonomous tractor to follow the paths, and the vehicle position differed from the manually driven paths by 0.264, 0.370 and 0.542 m for the wide, tight, and U-turn paths, respectively, with directional accuracies of 3.139°, 4.394°, and 5.217°, respectively, which are satisfactory for the autonomous operation of tractors on rubber or palm plantations. Therefore, this laser-based landmark detection and navigation system can be adapted to an autonomous navigation system to reduce the vehicle`s sensor cost and improve the accuracy of the positioning.

Highlights

Due to the rise in population, the demand and consumption for foods have increased significantly.This creates inevitable problems of labor shortages in agricultural production
The results show that the navigation system could navigate the tractor to run along the test course without collision with the traffic cones (Figure 17)
The root mean square (RMS) differences in position mostly happened at the curve, where the control system tended to drive close to the inner belt of the test course (Figure 17a, 18a)

Summary

Introduction

Due to the rise in population, the demand and consumption for foods have increased significantly. This creates inevitable problems of labor shortages in agricultural production. The implementation of agricultural robotics in outdoor environments can contribute to the ease of operation and reduce human drudgery. Many studies have been performed to develop sensors and control algorithms to solve the problem of the navigation of agricultural vehicles. Research on developing automatic autonomous machines for row-type plantations such as those for palm oil and rubber has attracted significant interest in the last 10 years throughout Asia. As the plantations are normally divided into plots that are not arranged in regular shapes, travelling from plot to plot is needed for continuous operation (Figure 1)

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