Applied Off-site and On-site Collective Multi-Robot Autonomous Building Manufacturing

Abstract

Construction is significantly behind other UK sectors in productivity, speed, human safety, environmental sustainability and quality. In addition to inadequate building supply and affordability in the UK, humanitarian demand and economic opportunity for construction is set to increase substantially with global population growth over the next 40 years. However, with an aging work-force and construction considered to be one of the most dangerous working environments, the industry needs to explore radically new approaches to address these imminent challenges. While increased off-site manufacturing provides a partial solution, its methods are not easy to automate. Where individual mass-produced parts can be moved efficiently through production assembly lines that separate workers from dangerous machinery, building manufacturing involves mass-customisation or one-off production at a larger scale. This requires machinery and people to move around, and potentially work inside of a fixed manufacturing job e.g. a prefabricated or on-site house, as various independent and parallel tasks are undertaken in safety-compromised, overlapping work-zones. To address these issues, this project investigates fundamentally new operational and delivery strategy for automation to offer new ways of working with robots.

Automation of shared construction environments requires robotic capabilities to be flexible and adaptive to unpredictable events that can occur (indoors or outdoors). Social insects such as termites, despite their small size and individual limitations, show an ability to work collectively to design and build structures of substantial scale and complexity; by quickly and efficiently organising themselves while also providing flexible, scalable coordination of many parallel tasks. Inspired by this model of manufacture, this project will develop an innovative multi-agent control framework that enables a distributed team of robots to operate in a similar way for the manufacture and assembly of buildings undertaken by off-site manufacture, on-site construction, or hybrid solutions using on-site factories. This requires the enhancement of existing robots, and development of new capabilities for collision avoidance and collaborative working. As many building tasks require specialist equipment, heterogenous teams comprised of different robot platforms such as agile mobile ground vehicles (UGVs), aerial vehicles (UAVs), alongside larger scale industrial robot arm, track and gantry systems, will be able to collaborate, and collectively undertake tasks beyond the capabilities of each individual robot such as lifting objects heavier than any one robot's payload capacity.

To address construction relevant challenges, we will integrate capabilities for additive manufacturing, manipulation and assembly for building and building-component scale manufacture, in addition to computational means for individual robots to make local decisions. The final research deliverable will be the demonstration of the world's first collective multi-robot building manufacturing system that can autonomously build parts such as a façade or roof, assemble a structure, or construct a freeform building pavilion. We will also integrate these technologies within prototype building systems themselves, to create a new type of 'active' building that can use a multi-agent system to self-regulate energy and harvest data to provide a closed operational ecology between design, manufacturing, construction and building use, revolutionizing the way we manufacture, operate and use buildings. Further, evaluation frameworks will be developed to assess multi-robot construction and obtain objective measures for collective systems to deliver greater resource efficiency, quality, speed, safety and up-time compared with established construction methods. In doing so, we will establish new metrics quantifying the impact of these technologies from both economic and environmental perspectives.

Planned Impact

The three main impact beneficiaries are the construction sector, society at large and the environment. The Collective Multi-Robot Autonomous Building Manufacturing system proposed in this application can provide substantial benefits by delivering the world's first autonomous multi-robot solution to off-site and on-site building manufacturing and construction. Such a system engenders the following benefits to the three beneficiaries as follows:

CONSTRUCTION
Global construction market growth is estimated to be worth GBP15 trillion by 2025, with 2 billion in population growth [1]. This represents substantial economic opportunity for the UK construction industry however, there is a predicted 20-25% decline in the construction labour force over the next decade due to an aging work-force [2]. UK productivity is already behind competing nations, with estimates that a G7 worker can achieve a task in 80% of a UK worker's time [2]. Further, Construction is an extremely dangerous activity, accounting for 2-3 times as many worker fatalities and non-fatal injuries than other industries [3]. This research would improve worker safety, provide logistic flexibility and profitability in the following ways:

-Productivity: increased up-time, and continuous manufacture through autonomous and scale-able resource allocation.
-Speed: Parallel operation combined & robot production provides a significant speed boost.
-Flexibility/Adaptation: Enables a shift away from fragmented approaches to a flexible, scale-able solution, by providing a framework which could be incorporated into many different manufacturing activities and utilized in diverse environmental and factory settings.
-Health & Safety: Reducing human labour for heavy lifting, working at height, and incorporation of collision avoidance capabilities for mobile vehicles will significantly decrease the three primary causes of worker fatality and injury [3].
-Quality: Multi-robot collaboration for off-site manufacture & on-site construction will decrease error tolerances of building manufacture and assembly, enabling high-precision design and manufacture, greater performance metrics and finish quality.
-Real-time BIM & Asset Management: Real-time monitoring and ID of BIM building assets will enable a continuous feedback loop between design, construction & digital means of performance evaluation, enabling highly efficient design and project management.

SOCIETY
Affordable buildings: While the UK Government pledged to construct 1 million new homes by 2020 and another half a million by 2022, Parliament noted there is no clear strategy on how to produce the quantity of housing in this period or to address affordability of housing [2]. The construction benefits listed above will significantly reduce the cost of construction and help achieve construction targets through expedited means of construction. Digitalization of construction is estimated to pass on GBP3bn in cost savings to consumers [4].

ENVIRONMENT
Digitalization of construction is estimated to create a 365,000 tCO2e reduction by 2027[4]. Increases in precision of building construction can allow methods such as additive manufacturing to reduce material waste and use, aligning design and filigree material placement with structural performance requirements, and through quantitative analysis possibilities of the autonomous manufacturing process relative to environmental impact performance metrics. The proposed smart building components will also regulate and distribute data and energy throughout buildings adaptively relative to environmental and energy demands, providing local environmental adaptation at sub-building scales, boosting building use environmental efficiency.
1.Construction 2025 Industrial Strategy: government & industry in partnership
2.The Farmer Review of the UK Construction Labour Model: Modernise or Die
3.Health & safety statistics for the construction sector in Great Britain
4.Made Smarter: Review2017