project specification

Modular Robotic System

A modular robot to gain a greater understanding of the practical issues that will impact the design of modular robotic equipment for use in space. This hardware also serves a dual purpose in supporting near-term terrestrial robotics research. The robot is heterogeneous, consisting of modules of several different types each designed to perform a particular simple function.

Specifications

Module size60 x 60 mm
Module weight115 - 125 g
Microcontroller25 MHz Atmel FPSLIC microcontroller/FPGA
Servohigh-precision brushless DC servomotors
SensorsQuantum Tunnelling Composite
Software simulation environmentC++

Overview

The robot is heterogeneous, consisting of modules of several different types each designed to perform a particular simple function. The modules are all designed for quick and easy manual reconfiguration, in this case using thumb-screws. The robot has been iteratively developed, hence there are two generations.

First-generation hardware

This version includes three module types: a rotational actuator module, a five-connector hub module, and a power and communications module. The joints are hinge-type actuated modules. The hub has a structure with five connection points arranged to provide a variety of connection angles including 90 degrees and 120 degrees. It is possible to construct both rectangular and hexagonal lattices for use in assembling larger structural configurations. The hub modules also provide power distribution and communications switching between neighboring modules.

The battery and communications module allows the robot to operate fully autonomously or in a tethered mode. The robot has passive “foot modules” to protect the other modules and to provide
a more uniform surface for locomotion.

Second-generation hardware

The gendered connectors of the first system are replaced with hermaphroditic connectors. Two new module types are added. The first is an actuated wheel intended for rover-like locomotion. The second module type is a digital camera that transmits images wirelessly to a controlling computer. The second generation system is redesigned with high-precision brushless DC servomotors and backlash-free harmonic gearboxes. The feet modules have tactile sensing capabilities based on QTC force sensors.

Simulation

A physics-based software simulation environment for modular robots in C++ has been developed which allows to construct robots using a variety of module types and to extend the simulation by adding additional types with compatible connectors.

References

Summarizes related work in modular robotics, and discusses a number of potential applications for modular robotics to future space exploration missions. Describes the design and manufacture of initial prototype hardware. Outlines a simulation and design environment capable of automated morphology.

Matthew D. Hancher, Gregory S. Hornby.

Wevolver 2022