The Tin Woodman first appeared in Frank Baum鈥檚 The Wonderful Wizard of Oz 120 years ago. Now real robot foresters are making their debut, planting trees rather than cutting them down.
The robotic foresters are the work of robot makers Milrem in partnership with the University of Tartu, both based in Estonia. Two versions are under development based on the company鈥檚 range of driverless ground vehicles. One type is a planter, the other a brush cutter, and both are autonomous. Both are the size of a small car and weigh about a tonne.
The planter carries more than 300 seedlings at a time and will plant a hectare of new forest in 5 to 6 hours, totalling between 1000 to 3500 seedlings depending on the species. It also records the exact location of each tree. Armed with this data, the brush cutter, equipped with a cutting tool and precision sensors, removes vegetation around the seedlings.
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Gert Hankewitz at Milrem Robotics says the robot foresters鈥� tracks exert less pressure on the ground than human feet and won鈥檛 damage the soil. Precise navigation is challenging, though, and requires a combination of laser-based LIDAR sensors, cameras and GPS.
LIDAR provides a 3D geometric representation of the environment, but gives relatively little data. High-resolution camera images fill in the gaps. 鈥淎ll the data is fused in real-time, complementing each other, and making autonomous driving in a forest a possibility,鈥� says Hankewitz.
The cameras are also used for image recognition, and provide a visual display for the operator if they need to drive the robot manually. The plan is for the robots to be largely autonomous, which presents challenges in surroundings which are unstructured and chaotic, unlike the open roads faced by self-driving cars and other robots.
Developers are tackling this with machine learning, using simulations for conditions which may not occur frequently in real life. This means the robotic foresters should be able to tell whether they can cross a given slope, ditch or stream, for example, without getting stuck.
鈥淭he robotic foresters will carry out the operation almost autonomously,鈥� says Hankewitz. 鈥淭he human operator, who will supervise four or five robotic foresters, will intervene only when necessary.鈥�
The hope is that the robot foresters will cost less than manual forest replanting or mechanised approaches with excavators.
Many countries around the world are looking to plant huge numbers of trees to help fight climate change. There are several plans to plant a trillion trees, which would add to the 3 trillion we currently have.
Andrew Davison at Imperial College London says that in a cluttered forest the cameras and LIDAR sensors should complement each other and enable the robots to identify obstacles and plot a course as they go.
鈥淭his is one of many interesting applications emerging which show that mobile robotics technology is maturing fast and enabling robots to tackle new types of task in difficult environments,鈥� says Davison.
Development of both robots is scheduled to be completed this year.
