Better performance of agricultural robots on slopes may now be possible, thanks to a control system designed at the Swiss Federal Institute of Technology Lausanne.
Uneven and sloped terrain can present difficulties for robots performing automated tasks on farms, which often means that attaching a tether to the machine is a practical compromise. Tethers also make robots easy to recover from the field, and can be used for connection to power sources, as well as data transfer.
However, in work to date, they have generally needed to have been attached low on the robot’s structure, in order to prevent them tipping over on sloped surfaces. This not only means that they do not clear surrounding crops, but presents a risk that they could become entangled by obstacles or damaged, said robotics engineer Max Polzin, who set out to address this constraint.
The low attachment of tethers has been necessary as controls have only considered the potential of robots to slip, not tip, he suggested in the journal Advanced Robotics. His new stability criteria for robots on slopes, coupled with a novel control device, appears to solve the problem.
Taller tethers reduce risks
In experiments in a laboratory and a sloped test field in Lausanne, he showed that the new approach allowed a tether to be mounted much higher on a four-wheeled robot than had previously been possible (0.81 metres compared to 0.27 metres).
Such a shift would be advantageous in a number of crop systems with significant slopes, such as vineyards and rice fields in some parts of the world. In these environments, automated weeding, planting and harvesting robots could replace risky manual work, making otherwise-viable sloped areas easier to use.
“The proposed approach has potential applications in steep terrain agriculture and could be expanded to other domains where tethered robots have been advantageous over untethered systems,” said Polzin.
“The results of this work are relevant for advancing the state-of-the-art in tethered robotics and providing novel solutions for agricultural automation.”
Building on the initial work, Polzin’s team are now planning to carry out further large-scale tests on an experimental farm, to further validate the approach.
