By Karen L. Edwards.
Collective robotic construction (CRC) specifically concerns embodied, autonomous, multirobot systems that modify a shared environment according to high-level, user-specified goals.
A Science Robotics study published this March states that ‘the increasing need for safe, inexpensive, and sustainable construction, combined with novel technological enablers, has made large-scale construction by robot teams an active research area.’
The study notes that 54% of the human population currently live in cities and that number is expected to grow to 66% by 2050. The researchers feel that collective robotics can help meet the construction demand in the midst of an ongoing labor shortage. CRC could also make construction safer for workers, with the Department of Labor citing that 20% of all worker injuries occur in construction.
The researchers were inspired by the extensive use of collective construction in nature for building nests, protection barriers, traps and mobility scaffolds. Where animal construction relies on reactive behaviors and ‘low-bandwidth communication,’ robots can rely on high-resolution sensors, high-speed communication and GPS to communicate their exact location for completing specific tasks.
Construction materials used in CRC are divided into two categories – discrete and continuous. Discrete materials would be square, rectangular or homogenous bricks, struts and sandbags. Continuous materials would be things like two-component foam, concrete and fibers.
The study says that “challenges pertain to CRC hardware, especially in relation to coordination, communication, and multimodal sensing.” The robots need to be able to adequately communicate and coordinate with nearby robots for success. “As more advanced sensors such as radar, depth cameras, laser imaging and ranging systems, and GPS become cheaper and more readily accessible, they may play a bigger role in the field. ”
The researchers reference two published systems, UAVs and climbing robots, that can be used to develop a metric that measures constructed volume relative to time, the number of robots used and the volumetric size of each robot. “A flying robot [UAV] has higher energy expenditure and lower payload than a climbing robot but may fly directly between material cache and deposition sites. Reversely, climbing robots can carry more but have to traverse through previous construction.”
The study is the first step in really determining how robotics can make an impact in construction. Further study is needed to develop performance metrics, evaluate the reliability of CRC and it’s ability to adapt to changes in movement, or expected behaviors of the other robots. There also needs to be more research in order to determine where humans fit into the CRC picture to oversee work, make adjustments and corrections when there is an error and in the support and maintenance of the robots.