This paper presents a new 6 DOF soft robotic
manipulator intended for colorectal surgery. The manipulator,
based on a novel design that employs an inextensible tube to
limit axial extension, is shown to maximize the force exerted
at its tip and the bending angle, the latter being measured
with a soft sensing skin. Manufacturing of the prototype
is achieved with a lost-wax silicone-casting technique. The
kinematic model of the manipulator, its workspace, and its
manipulability are discussed. The prototype is evaluated with
extensive experiments, including pressure-deflection measure-
ment with and without tip load, and lateral force measurements
with and without the soft sensing skin to assess hysteresis. The
experimental results indicate that the prototype fulfils the key
design requirements for colorectal surgery: (i) it can generate
sufficient force to perform a range of laparoscopic tasks; (ii) the
workspace is commensurate with the dimensions of the large
intestine; (iii) the soft sensing skin only results in a marginal
reduction of the maximum tip rotation within the range of
pressures and external loads relevant for the chosen application.