Supercoiled polymer (SCP) artificial muscles exhibit many desirable properties such as large contractions and high power density. However, their full potential as robotic muscles is challenged by insufficient strain or force generation – non-mandrel-coiled SCP actuators produce up to 10-20% strain; mandrel-coiled SCP actuators often lift up to 10-30g of weight. It is strongly desired but difficult to obtain SCP actuators that produce large strain and large force. In this paper, the design, characterization, and modeling of helically wrapped SCP (HW-SCP) actuators are presented, which can produce up to 40-60% strain and lift more than 90g of weight. By adjusting their configuration parameters, their strain and force performance can be changed. Experiments are conducted to characterize the force production, strain, and speed of HW-SCP actuators. A Preisach hysteresis model and a polynomial model are adopted to accurately capture the actuator behaviors. This work contributes to high-performance artificial muscles.

This paper presents a novel manipulator for aerial vehicles to perform grasping and manipulation tasks. The goal is to design a low-cost, relatively light but strong manipulator with a large workspace and compact storage space that can be mounted on an unmanned aerial system. A novel design solution based on the Spiral Zipper, an expanding tube, combined with tether actuators is presented. A model of the system is introduced and the control method and pose estimator are developed and tested with some experiments showing the reliable performance of the overall system. An experiment with a self-sealing suction cup gripper demonstrates manipulation while mounted on the aerial vehicle frame.

The PaintPot manufacturing process is a new way to create low-cost, low-profile, highly customizable potentiometers for position sensing in robotic applications. It uses widely accessible materials, requires no special expertise, and creates custom potentiometers in a variety of shapes and sizes, including curved surfaces. PaintPots offer accuracy and precision performance comparable with commercial (non-customizable) options through a calibration process that trades small computation for cost. This paper includes detailed PaintPot manufacturing and calibration processes, and experiments that validate the accuracy, precision, and lifetime performance of PaintPots, comparable to commercial sensors. We also provide a case-study application in the SMORES-EP modular robot, and show how the PaintPot process can be used to create resistive surfaces capable of sensing position in 2D on planes and spheres.