A prototype of an autonomous construction vehicle weighing 12 tonnes has demonstrated that it can operate on very difficult terrain without a human operator.
A Swiss-German team has become the first to successfully convert a type of excavator that can 鈥渨alk鈥� on extendable struts and handle steep slopes so that it can operate entirely independent of a human operator. They used the adapted walking excavator to build a 4-metre-tall stone wall and grab trees for mock forestry work. They also used it to dig out a trench containing live ammunition from the second world war, a demonstration of scenarios where autonomous vehicles could be used to limit safety hazards for human operators.
While some autonomous construction vehicles such as dump trucks are already being used in large mines, general wheeled or tracked excavators aren鈥檛 at that point yet. Walking excavators are versatile machines in construction, and were first designed for work on mountainsides.
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Making them autonomous removes humans from potentially dangerous situations, addresses labour shortage issues and means vehicles can operate for longer, says at ETH Z眉rich in Switzerland. He and his colleagues converted the machine using algorithms and new control mechanisms along with lidar, which is used to make a 3D map of its surroundings using pulses of light.
The prototype was programmed to operate both an excavator bucket and a two-finger gripper. The resulting machine was dubbed the Hydraulic Excavator for an Autonomous Purpose (HEAP).
鈥淭here is no excavator I know of that can [autonomously] execute complex tasks such as excavation of free-form embankments or building a dry stone wall,鈥� says Jud. One of the hardest things in converting the excavator from human-operated to a computer running the open-source software Ubuntu in its cabin was adapting the controls to direct the machine鈥檚 hydraulic pumps, he says.
Jud says the autonomous machine is roughly on a par with human operators in terms of the accuracy with which it undertakes tasks, but not yet as fast. The vehicle achieved level 4 out of the 5 levels of autonomy laid out by industry standards for driverless vehicles, meaning it can work independently of humans under normal circumstances, but not in extraordinary ones.
HEAP is a proof of feasibility device for now, rather than something that will be building mountain roads or desert trenches any time soon; Jud says commercialising autonomous walking excavators is 鈥渟till a bit away鈥�.
Automation in Construction
