Inspired by the living bridges formed by ants, swarm robots have been
developed to self-assemble bridges to span gaps and self-disassemble them.
Self-disassembly of bridges may increase the transport efficiency of swarm
robots by increasing the number of moving robots, and also may decrease the
efficiency by causing gaps to reappear. Our aim is to elucidate the influence
of self-disassembly of bridges on the collective flow characteristics of swarm
robots in a single-lane and periodic system with a gap. In the system, robots
span and cross the gap by self-assembling a single-layer bridge. We consider
two scenarios in which self-disassembling bridges is prevented
(prevent-scenario) or allowed (allow-scenario). We represent the horizontal
movement of robots with a typical car-following model, and simply model the
actions of robots for self-assembling and self-disassembling bridges. Numerical
simulations have revealed the following results. Flow-density diagrams in both
the scenarios shift to the higher-density region as the gap length increases.
When density is low, allow-scenario exhibits the steady state of repeated
self-assembly and self-disassembly of bridges. If density is extremely low,
flow in this state is greater than flow in prevent-scenario owing to the
increase in the number of robots moving horizontally. Otherwise, flow in this
state is smaller than flow in prevent-scenario. Besides, flow in this state
increases monotonically with respect to the velocity of robots in joining and
leaving bridges. Thus, self-disassembling bridges is recommended for only
extremely low-density conditions in periodic systems. This study contributes to
the development of the collective dynamics of self-driven particles that
self-assemble structures, and stirs the dynamics with other self-assembled
structures, such as ramps, chains, and towers.Comment: 13 pages, 9 figure