  As an important contributor to GDP growth, the construction industry is
suffering from labor shortage due to population ageing, COVID-19 pandemic, and
harsh environments. Considering the complexity and dynamics of construction
environment, it is still challenging to develop fully automated robots. For a
long time in the future, workers and robots will coexist and collaborate with
each other to build or maintain a facility efficiently. As an emerging field,
human-robot collaboration (HRC) still faces various open problems. To this end,
this pioneer research introduces an agent-based modeling approach to
investigate the coupling effect and scale effect of HRC in the bricklaying
process. With multiple experiments based on simulation, the dynamic and complex
nature of HRC is illustrated in two folds: 1) agents in HRC are interdependent
due to human factors of workers, features of robots, and their collaboration
behaviors; 2) different parameters of HRC are correlated and have significant
impacts on construction productivity (CP). Accidentally and interestingly, it
is discovered that HRC has a scale effect on CP, which means increasing the
number of collaborated human-robot teams will lead to higher CP even if the
human-robot ratio keeps unchanged. Overall, it is argued that more
investigations in HRC are needed for efficient construction, occupational
safety, etc.; and this research can be taken as a stepstone for developing and
evaluating new robots, optimizing HRC processes, and even training future
industrial workers in the construction industry.
