Design and Characterization of a Modular Hybrid Continuum Robotic Manipulator

We present a new design of a multi-DOF modular soft/rigid hybrid robotic manipulator that includes integrated electronics and is composed of several modules which each provide 1-2 degrees of freedom of motion. To control the robot, we present a new variant of the piece-wise constant curvature model made possible due to the geometry of the robot. Embedded inertial measurement units and pressure sensors are the sole sensors used in conjunction with the robot model to determine its kinematics. With the model, the soft robot can be controlled using traditional forward and inverse kinematics. Thus, its sensing and control are relatively simple compared to other soft robots. Additionally, it has a higher payload than other soft robot arms. We present models for each of the robotic joint modules created, as well as a new model for a bellows actuator based on its mechanics. With these models, we perform calculations about the stiffness of each module, and we compare these to experimental data on the modules and entire robot. The modeling introduced in this article had errors of less than 5%, and the robot arm achieved positioning accuracy of less than 1 cm.