  We propose a distributed planning method with asynchronous execution for
multi-agent pickup and delivery (MAPD) problems for environments with
occasional delays in agents' activities and flexible endpoints. MAPD is a
crucial problem framework with many applications; however, most existing
studies assume ideal agent behaviors and environments, such as a fixed speed of
agents, synchronized movements, and a well-designed environment with many short
detours for multiple agents to perform tasks easily. However, such an
environment is often infeasible; for example, the moving speed of agents may be
affected by weather and floor conditions and is often prone to delays. The
proposed method can relax some infeasible conditions to apply MAPD in more
realistic environments by allowing fluctuated speed in agents' actions and
flexible working locations (endpoints). Our experiments showed that our method
enables agents to perform MAPD in such an environment efficiently, compared to
the baseline methods. We also analyzed the behaviors of agents using our method
and discuss the limitations.
