Tag Archives: control systems

167-172 T. Oksanen
Laser scanner based collision prevention system for autonomous agricultural tractor
Abstract |
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Laser scanner based collision prevention system for autonomous agricultural tractor

T. Oksanen

Aalto University, Department of Electrical Engineering and Automation, Otaniementie 17, 02150 Espoo, Finland; e-mail: timo.oksanen@aalto.fi

Abstract:

In manned agricultural vehicles, the automated systems assist the driver by reducing the workload. This is achieved e.g. by using an automatic guidance system to steer the tractor along the desired path. However, increasing automation tends to cause a reduction of awareness, so risks to collide obstacles in the field are higher. In this study, an autonomous tractor was equipped with front side laserscanner (LIDAR) to sense the environment in front. The laserscanner scans the environment at 50 Hz rate. The theoretical maximum range of the sensor is 25 m, but it was found in the tests, that in agricultural field conditions, the feasible range is not more than 7 m, due to the sunlight disturbance. Agricultural vehicles weigh tons, so the deceleration is limited and the limited range causes challenges to detect the obstacle and decelerate without colliding it. The developed algorithm is able to detect solid objects, like electricity poles in the trajectory. The deceleration algorithm is based on the known dynamics and actuator delays of the tractor locomotion system, by taking into account the maximum deceleration rate. In field tests, the system was evaluated in grass fields. In the first test, the system was tested with real electricity poles with no implement. In the second test, the system was tested with a mower and by using artificial obstacles placed into the grass. The system was able to detect the obstacles with high accuracy and stop precisely, but in the corners of the field the system caused false positives when the sensor was sensing beyond the edges of the field plot.

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109-113 M. H. Jorgensen
Agricultural Field Machinery for the future – from an Engineering Perspective
Abstract |

Agricultural Field Machinery for the future – from an Engineering Perspective

M. H. Jorgensen

Department of Mechanical and Manufacturing Engineering, Aalborg University,
Fibigerstraede 16, DK-9220 Aalborg East, Denmark; e-mail: mhj@m-tech.aau.dk

Abstract:

When analyzing agricultural field machinery from an engineering perspective, it appears that the technical development has progressed in a different pattern compared to what is seen in other industrial mechanical or tooling systems. As in other fields, the technical development of agricultural field machinery has brought new technical and engineering elements into use. Especially for tractors and combine harvesters, where modern mechanical and control engineering solutions are implemented. Developing work on implements has more concerned on monitors, sensors and actuators for the classical adjustment elements. It is special for agricultural field machinery, that the overall design and the tooling principles have changed very little even since the time of horse driven units and during the following up-scaling of tractor and implement size, which has continuously taken place until now, where the power of an tractor is more than 10 times bigger, than for the first tractors. When analyzing the design of industrial mechanical or tooling systems, the technological and engineering based development has in many cases been accompanied by change of working principles, operation interactions and of the overall design and layout. The assumption is that the development of agricultural field machinery is in a stage where further up-scaling is not the best solution due to optimization of the overall production economy. Instead it is expected probable, that the next design step will involve a radical redesign of the whole systems for the different types of implements. A logical approach is development of compact integrated tooling systems, where propulsion and tooling systems will be integrated in harmonic systems and the design will be dedicated to specific operations. The sizing then, will be balanced due to a new set of conditions.

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