Abstract:
Modular manipulators gained popularity for their implicit feature of “reconfigurability”—
that is, the ability to serve multiple applications by adopting different configurations. As
reported in the literature, most of the robotic arms with modular architecture used specific
values of twist angles, e.g., 0 deg or 90 deg. Further, the number of degrees-of-freedom
(DoF) is also kept fixed. These constraints on the design parameters lead to a smaller solution
space for the configuration synthesis problems and may result as no-feasible solution
in a cluttered work-cell. To work in a realistic environment, the task-based customized
design of a manipulator may need a larger solution space. This work deals with the extension
of the modular architecture from conventional values to unconventional values of
design parameters, keeping the degrees-of-freedom also as variable. This results into an
effective utilization of modular designs for highly cluttered environments. A three-phase
design strategy is proposed in the current work. The design strategy starts with the decision
of optimal number of modules required for the given environment in the first phase, which
is followed by task-based “configuration planning” and “optimal assembly” in the second
and third phase, respectively. Three types of modules are proposed with same architecture
and different sizes—heavy (H), medium (M), and light (L). The configuration planning
includes detailed discussion on the type-selection of the modules and their possible combinations.
Comparison of all possible n-link combinations is analyzed based upon the optimized
results with respect to the minimum torque values. Case studies of a power plant
with two different workspaces are included to illustrate the three-phase strategy representing
the importance of modularity in nonrepetitive maintenance tasks.
