Design of a modular continuum robot segment for use in a general purpose manipulator

This thesis presents the development of a tendon driven continuum robot segment with a modular design. This work begins by reviewing existing literature surrounding continuum and modular robotics to better understand the current state of the art; and look for opportunities to make a novel contribution. The proposed design fills gaps in current research by showing a significant lifting capabilities due to a novel interlocking vertebrae system to restrict undesired torsional movement, while allowing bending in two degrees of freedom. Continuum segment modularity is achieved by embedding the actuation, control electronics and a battery in one end of the segment. This avoids the need for a bulky actuation unit and allows a varying numbers of segments; or a range of end effectors; to be connected via a universal interface integrated into the tip and the base. The design was developed through a number of iterations until a final solution was reached. The segment features a continuous flexible core made from soft silicone, combined with rigid 3D printed vertebrae evenly distributed along its length. It is actuated by two antagonistic tendon pairs, each of which is driven by a single geared DC motor in a custom design gearbox assembly. The design features a hollow central bore running its entire length which is demonstrated to be used for fluid flow and a control line channel for a tip mounted end effector. The three design iterations which feature the interlocking vertebrae were subjected to quantitative experiments to evaluate workspace, lifting capabilities and torsional rigidity. Finite element analysis was conducted to verify the strength of key components and optimise geometry. A compact electronics system was created that is capable of wired or wireless control, and allowing external or internal battery power was created. A control system was developed for the final iteration, using kinematics to successfully provide position control. The modular segment was demonstrated in a range of applications; fire fighting drone, a pick and place manipulator, and snake robot. The final segment was capable of lifting a 2.5 kg payload.