A snake inspired robot using ball-gear joints to minimise actuation requirements

In this paper, we discuss the manufacture and testing of a modular snake inspired robot, designed with the specific objective of minimising actuation requirements to enable serpentine movement, whilst still permitting dorso-ventral motion. To achieve this, we use ball gears to increase the range of motion at joints that are connected to the robotic snake body by linkages. While we use different motors to enable both dorso-ventral and lateral kinematics, the research presented here focusses on the lateral (serpentine) kinematics. The serpentine kinetics of the robotic snake are mapped for both linear and non-linear trajectories. We find that despite our robot's use of simple actuation mechanisms, serpentine movements leading to forward motion are possible. The paper instigates new scope for the use of ball gear mechanics to simplify serpentine movement in modular robots, whilst still permitting dorso-ventral kinematics through the same joints.