Robot field trial hits the ground

Watching 500 kg robots slipping and sliding on a muddy hillside at a recent demonstration was all part of a day’s work for principal engineer Dr Fiona Stevens McFadden and PhD students Payam Nori Zadeh and Dhanika Ratnayake from Paihau—Robinson Research Institute.

Payam driving the robot in a regional forest at Taupō.
Payam driving the robot in a regional forest at Taupō.

They were part of a multidisciplinary team, sharing with the Lake Taupō Forest Trust the results of a three-year research project. The team included researchers from four other universities—Auckland, Massey, Canterbury, and Otago—as well as Lincoln Agritech and Crown research institute Scion.

“Massey built a large demonstrator robot to integrate the research,” says Fiona. “Our work at Paihau—Robinson is about moving a wheeled vehicle around in rugged environments, which can be anything from a forestry plantation, to a mine or even another planet—anywhere the terrain is unknown, or there are natural hazards, and where GPS signals may be weak.”

The Paihau—Robinson contribution focused on dynamics and control of the robot’s movement. Other researchers worked on different aspects of the robot’s operation such as people detection and avoidance, navigation, mapping the environment, robot learning for autonomous systems, and taking the ‘noise’ out of images to aid navigation.

Concern for safety was a key part of Fiona’s initial interest in this work. “I started looking at behaviours and the sensing required to have a robot operating in a safe manner—for itself, for the environment, and for people,” she says. “I decided to look at wheel/terrain interaction, where you might have a robot rolling over or slipping.

“A lot of safety systems rely on the robot remaining in control in an environment. If the robot loses control, then you’re in trouble. Little research had gone into wheel/terrain interactions, so this looked like a useful place to start.”

Forestry is an ideal industry to test the systems and Payam found it useful to talk with the forestry workers on the day.

“We had planting and harvesting contractors, as well as those who are part of the iwi ownership of the forests and Lake Taupō Forest Trust board, and who also work in the industry. These guys all operate machinery in this sort of environment, have a good understanding of the issues and know what to do to keep themselves safe. They were interested in the work because it’s aligned to their daily jobs,” Payam says.

The robot used at Paihau—Robinson is a research model and not to scale, and the plan is to apply the methodologies to commercial-scale vehicles. Payam is finalising the controller and slip/skid estimators, and finishing field testing, while Dhanika will tackle the roll-over issue, adding prediction and mitigation systems to the work Payam has completed.

Further work will also include exploring commercialisation and real-world applications of the technology to improve safety.